Photo courtesy: Kazi Faiza Tasnim Neha

Owls don’t have eyeballs like many other animals. They have eye tubes or cylinders, rod-shaped eyes that do not move in their sockets as eyeballs do. Instead, owls have to move their bodies or heads in order to look around.

Fact Factory Album

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Photo courtesy: Kazi Faiza Tasnim Neha

“A Grizzly bear’s bite is strong enough to crush a bowling ball”

Grizzly bears have a bite-force of over 8,000,000 pascals, enough to crush a bowling ball. Grizzly bears have a muscular hump on the upper back, which helps differentiate them from other bears in the wild.

Fact Factory Album

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Carbon Reduction for  Sustainable Development

-A way to Sustainable Development

Dr. Mohammad Ekramol Islam
Professor of Mathematics
Dean, Faculty of Business &
Treasurer, Northern University Bangladesh
Chief Editor, Journal of Business & Technology
Editor, Nature Study Digest
Email. meislam2008@gmail.com

Introduction:

Jan Baptist
van Helmont

Carbon compounds have the great ability to form polymers at different temperatures and therefore, they form the basis of all lives on Earth. For the existence of life, energy is a must. So, the Carbon-Nitrogen cycle provides some of the energy produced by the Sun. In 1640, the Flemish chemist Jan Baptist Van Helmont (1580-1644) first observed Carbon Di-oxide to burn charcoal in a closed vessel. A.L. Levoisier. (1743-1794) proposed the name ‘Carbon’ in 1789 fr

Levoisier

om the Latin carbo meaning ‘Charcoal’. In 1815, Sir Humphry Davy (1778-1829) received a letter from some Newcastle miners, which told of the danger they faced from Methane gas. The gas often filled the mine and could be sparked off by the candle they used in their helmets to light their work. The resulting fire and explosion caused many deaths. Sir Davy separated the flame from the gas and introduced a new lamp named ‘Davy Lamp’ for mining, which became popular that time and was widely used. In the same year, George Stephenson, the railway engineer, invented a safety lamp for miners. Later in 1823, Humphry Davy and Michacel Faraday successfully liquefied Carbon Di-oxide at elevated (higher than normal) pressure.arbon is one of the very few elements known from the ancient time. It is the 15th among the most abundant elements in earth’s crust and 4th of most abundant elements on earth by mass, after hydrogen, helium, and oxygen. It is the 2nd most abundant element in a human body (18.5% appx.), the 1st being the Oxygen.

Development:  

Humphry Davy

Development can be defined as “The process in which someone or something grows or changes and becomes more advanced”. For examples; (a) Transportation: It can be cars, buses, ships etc. (b) Consumptions: It can involve anything from packed foods, refrigeraton, frozen food etc. But this traditional development is not free from danger as for transportations or producing consumer goods requires energy, and if the energy came from the fossil fuel, may contribute to air pollution – a threat to human existance. We know, resources are limited and demands are unlimited, and it is true that, human beings play the main role in development. Therefore, they must be very conscious about their development as well as their existence in this World.

Malthus

In 1779 Thomas Robert Malthus (1766-1834) wrote “Famine should be the last, the most dreadful resource of nature. The power of population is so superior to the power of the Earth to produce subsistence for man, that premature death must in some shape or other visit the human race.”

In support of Malthus’s philosophy, Professor Paul R. Ehrlich of Stanford University and his wife Anne Ehrlich have written a book entitled “The Population Bomb” in 1968. Later, they presented the ‘IPAT model’ in support, which can be represented as –     I = P × A × T

That is, the impact ‘I’ of any group or nation in the environment is the product of its population size ‘P’, multiplied by a per capita affluence ‘A’ as measured by consumption, which in turn, is multiplied by a measure of the damage done by the technologies ‘T’, involved in another way.

Pollution = (Population) × (Goods/Pollution) × (Pollutants/Goods)

Relevancy of Development and Carbon

We have already mentioned that Carbon compounds form the basis of all known lives on earth because of their ability to form polymers at different temperatures. Food, cloths, shelter, health, and medication are the basic needs of human beings. For satisfying these needs, we have invented a lot of things including different vehicles, consumer’s goods, and residential infrastructures etc. Industrial revolution has the huge contribution to satisfy needs of the people and to make their lives comfortable. We are very much aware of the fact that the main motto of industrial revolution was replacing muscle power with machine power. But to run machines, we need energy or power. Producing power generates a lion share of Carbon compounds globally. The main sources of Carbon emission based on data of  2015 is given in Chart-1:

Chart-1: Main sources of Carbon emission

Electricity production generates the largest share of CO₂ gas emission. Approximately 67% of our electricity comes from burning any form of fossil fuel, mostly coal and natural gas. Over 90% of the fuels for transportation are Petroleum based, which include Gasoline and Diesel – both compounds of Carbon. Carbon emission from industry occurs due to certain chemical reactions, necessary to produce goods from raw materials, and burning of fossil fuels for energy. It is obvious, we have a very close connection to Carbon or Carbon compounds for our development.

Why Carbon is so harmful?

a) Human activities in the name of development emit about 29 billion tons of Carbon Di-oxide per year, while volcanoes emit between 0.2-0.3 billion tons. At present, half of the CO₂ released from the burning of fossil fuels remains in the atmosphere and is not absorbed by vegetation and marine water. CO₂is the primary greenhouse gas emitted through human activities. CO₂ is naturally present in the atmosphere as part of the Earth’s Carbon cycle (natural circulation of Carbon is in the atmosphere, oceans, soil, plants, and animals). Human activities for their development are altering the Carbon cycle both by adding more CO₂ to the atmosphere and at the same time reducing the ability of natural sinks of CO₂, like deforestation. A list of sovereign states and territories is prepared by European Commission and Netherlands Environmental Assessment Agency in 2015, based on CO₂ emission due to certain forms of human activity. According to the agency the global CO₂ emission by 2015 was 36,061,710 kilo ton. The top 10 largest CO₂ emitter countries (shown in Chart-2) produce 27,336,892 kilo ton, which accounts for 75.81% of the total global emission.

Chart-2: The top 10 largest CO₂ emitter countries

Bangladesh, with a population of 170 million, contributes only 0.14% to the global emission of CO_2. It is due to its population and economic growth, which are leading the country towards an increased demand of energy.

b) Carbon Di-oxide gas can be toxic and very harmful to the human beings. Increasing the CO₂ gas levels higher than 5% in the room is enough to kill a human being.

c) Increased CO₂ gas in the atmosphere can destroy ozone layer. As the consequences of ozone layer depletion, people can suffer from high blood pressure, headache, twitching the muscles and skin cancer.

d) Rising the levels of CO₂ gas stimulates sympathetic nervous system which may be dangerous in some patients already having systematic hypertension.

We cannot ignore the term development but have to find out the way where development will take place without harming our mother planet and the way in sustainable development. Common use of the term sustainability began with the 1987 publication of the World Commission on Environment and Development Report “Our Common Future” and then defined sustainable development as “Development that meets the needs of the present without compromising the ability of future generations to meet their own needs” and described that it contained three major sections, viz.,

1. Healthy Environment
2. Healthy Economy
3. Healthy Society

A Healthy Environment:

A list of environmental indicators for sustainable development is given below:

If all the indicators belong to the normal range, it is satisfactory; but by analyzing the indicators discussed above, it is clear that development creates problems even Carbon is not associated with them. Some of those factors can cause maximum damage to life and property like, acid rain, mainly caused by Sulphur Di-oxide and Nitrogen oxides can lead to devastating consequences. They react with water in the atmosphere to form Suphuric and Nitric acids, which return to Earth’s surface as acid rain, destroying huge number of organisms and infrastructures. On the other hand, the main pollutants associated with poor air quality are – Sulphur Di-oxide (SO₂₎, Nitrogen oxides (NO_x) Particulates (PM₁₀) and volatile organic compounds (VOC_s), which can be mentioned specially, as they can create respiratory problems, particularly among the young and aged people.

 Socio-Economic Indicators

If we analyze the above factors, we can observe that the better the socio economic condition more the Carbon emission and it is true that Carbon and Carbon compound are the main culprits for environmental pollution. So, it’s the challenging issue for the present world to continue the development for the mankind without compromising with environmental damages. Hence, for a sustainable development (i.e., to reduce Carbon), we have to popularize the following concepts:

More GDP > More energy & transportation > More production > More consumption > More population

a) By Popularizing the Green Energy

For ensuring sustainable development we have to ensure the use of renewable energy or green energy instead of traditional or non-renewable energy. Brief descriptions of green energies are given in the following table:

b) By Adopting the Green Technology:

Use of green technologies helps us to reduce Carbon or Carbon-compound by using the energy in the efficient way. According to a recent research from the American Council for an Energy Efficient Economy (www.aceee.org), today it takes less than half the energy to produce a dollar of economic output as it did in 1970. According to Nastu 2008, by using green technology, steel manufacturing companies, and computer systems, increase the energy efficiency by 16.7% and 2.8 million percent respectively. On the other hand, some organizations in Japan have become successful in reducing their Carbon emission to 0; listed in the table:

c) By Green Transportation:

It is any sort of transportation or vehicle, which has no negative impact on the environment. Bicycle, electric scooters, bikes, solar cars, and train are green vehicles, which are powered by solar, electric, wind, or bio-fuel energy. Such public transports (buses, trains) are considered as green transports. Green or cleaner transportation has been introduced in some countries, like Brazil, where cars run on bio-fuel i.e., Ethanol or Ethanol-petrol mixture, obtained from specially grown crops. In many countries, cars are now running with compressed natural gas (CNG) as fuel.

 d) By Avoiding Bomb Method:

Bombs are used for extraction of stones which involves use of dynamites that cause the destruction of the pristine environment of the area that is covered by the bomb. For example, ‘Bomb method’ has destroyed the pristine environment of Sylhet’s Jaflong area, which is considered one of the most attractive tourist spots in the country.

e) By developing Carbon Capture and Storage Technologies

f) By Applying Polluters’ Pay Principle:

We can suggest implementing the polluters’ pay principles which means that in all situations costs of cleaning up are borne by polluters themselves and not by the tax payers. This is because awareness does matter for ensuring sustainable development.

g) By Reducing Dependence on Chemical Fertilizers and Pesticides:

It is done by adopting new methods for their more efficient uses such as:-

• Granular System of Fertilizer Application (GSFA)
• Integrated Plant Nutrition Management (IPNM)
• Integrated Pest Management (IPM) by Promoting Organic Agriculture (OA)

h) By Popularizing 7-R Concepts:

The 7-R concept and their brief description are given in the table below:

i) By popularizing the use of Eco-friendly Infrastructure Ingredients.

Conclusion:

The main purposes of Carbon reduction for sustainable development are to regulate the exploitation of natural resources and to protect environmental degradation. It is done to maintain environmental quality, balance ecosystems, preserve biodiversity, and regulate exploitation of natural resources. The Carbon reduction is also done to adopt engineered technology without creating adverse effects on environment. Along with that, formulation of suitable environmental rules and regulations, and their effective implementation is also important. Obviously, the Carbon molecules, we have so far added to the atmosphere, will not go away overnight. But by understanding the impact of Carbon and Carbon compounds, if we take positive steps towards the reducing of our emissions; we may avoid the worse effects of upcoming Climate changes. To do that we have to be aware of ourselves, create awareness among people, and have to work as a global community, otherwise each and every one of us is going to suffer the consequences in the days to come.

References:

1. S. Energy Information Administration (2016).
   Electricity Explained – Basics
2. http://www.learner.org/interactives/garbage/solidsolut.htm
3. https://www.wikihow.com/Reduce-Solid-Waste
4. 2.epa.gov/recycle
5. d esig nrulz.com/produ ct-d esig n/2012/11/45-ideas-of-how-to-recycle-plastic-bottles/
6. emag.suez-environnement.com/en/a-second-life-for-waste?gclid=CPGRqfKP37oCFcM34godLwcAhQ
7. ca Irecyc le.ca.gov/reducewaste/ho me/
8. epa .gov/regio n9/waste/solid/reduce.htm
9. Bigghan Chinta; January 2018.

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Nature Study Society of Bangladesh (NSSB)
Activity Report 2013-2014
Nature Study Society of Bangladesh (NSSB) is a non-profitable, non-political and non-government voluntary organization, dedicated for the conservation of nature and its resources. Established in 1996 with the active Life Members of Notre Dame Nature Study Club, it was registered under the Societies Registration Act, 1860 (Registration No: S-3543(332/04) on Jan. 13, 2004.
As NSSB is a leading-edge multi-disciplinary organization, it has been working for the advancement of environment-friendly sustainable development, awareness building and educational programs keeping a good pace with such organizations home and abroad, since its beginning on August 30, 1996. A few of the notable activities that the organization (NSSB) has performed during 2013-2014 are mentioned below –

NSSB Activities during 2014
Participation in Channel-I Prokriti-Mela 2014
Nature Study Society of Bangladesh (NSSB), in collaboration with Notre Dame Nature Study Club (NDNSC) took part in “Grameen Phone Cahnnel-I Prokriti-Mela 2014” on January 18, 2014. The day-long colorful festival was organized by one of the most renowned environmental organization “ Prokriti-O-Jibon Foundation” at its own premises. Notre Dame Nature Study Club was honored with the Life-time achievement award by the Prokriti-O-Jibon Foundation, an honor awarded every year to persons or organizations with notable contribution to nature or environment. Fr. Dr. Hemanto Pius Rozario, CSC, Principal, Notre Dame College and Mr. Mizanur Rahman Bhuiyan, Founder of the club and Founder Chairman, NSSB, received the Crest of Honor for the Club from the Directors of Prokriti-O-Jibon Foundation and Chennel-I. The CEO of Grameen Phone (a Notredamian) was present on the occasion in presence of the members of NDNSC and NSSB with all participants of the Prokriti-Mela 2014.

Conduction of the GROUND TRAINING PROGRAM (GTP)
The GTP is a foundation training program mandatory for the members of any Nature Study club and is conducted under the supervision of Nature Study Society of Bangladesh (NSSB) and its Units. It is a cornerstone to the members as the history, ideologies, aims and objectives, activities and policies of such a club are introduced elaborately to the newcomers. Mr. Mizanur Rahman Bhuiyan, the Founder of Notre Dame Nature Study Club (NDNSC) and also the Founder Chairman of Nature Study Society of BD (NSSB), introduced it first at Notre Dame College in 1987 for a better understanding and development of the club-members. Now, the training is conducted by trained NSSB members, under his able guidance, at Notre Dame College and many other places where a Nature Study Club is established. This year, GTP was conducted for NDNSC members on January 17, 2014 (Friday); about 80 members participated; Mr. Bhuiyan conducted the training.
Conduction of Photography Training Program (PTP) for the students of Notre Dame College
Nature and Wildlife photography is one of the major activities of NSSB. Apart from contributing to the photography, NSSB provides a 14 days Basic Photography Training Program (PTP) to its members and units of the society as well as to all Nature Study Clubs under our monitoring. Like every year, NSSB trainers conducted the Photography Training Program (PTP) to NDNSC members. The training was organized by the club and 48 members participated and certified. The training was guided by Mr. Shuhan Syeed, Director, NSSB and Life Member, NDNSC; other notable NSSB trainers were Mr. Redhwan Bashar, Mr. Salman Bin Sultan, Mr. Rounak Saha Niloy and Mr. Diptungshu Mazumder Ratul, all Life Members of NDNSC.
Participation in the “WORLD WILDLIFE DAY” Rally
Fifty NDNSC members along with a good number of NSSB members participated the rally and subsequent seminar on the ‘World Wildlife Day’ on 3rd March, 2014, organized by the Govt. Forest Department, with a view to protect the wildlife of Bangladesh. The colorful rally started from the Doel Chattor and ended at the Press Club. A beautiful fair was also organized by the department, where lots of environmental organizations placed their stalls to share their activities towards the conservation of wildlife in Bangladesh. The team was guided by Mr. Biplob Dev, Director, NDNSC and Life Member NSSB.

Field Trip at Ramna Park, Dhaka

A field Trip was held at Ramna Park, Dhaka on March 17, 2014 along with NDNSC members. The participants observed the natural beauty of the park and prepared a list of flora and fauna under observation from 7:30 am to 11 am. The trip was guided by Mr. Shuhan Syeed, Director of NSSB and Life Member of NDNSC.

Participation in the “International Forest Day” Rally
The Govt. Forest Department organized a rally on March 21, 2014 in order to observe “The International Forest Day”. Five members of NSSB and 30 members of NDNSC took part in the rally and the following seminar. The whole team was guided by Mr. Biplob Deb, Director, NDNSC and Life Member, NSSB. Considering ‘Save Forest for Life and Livelihood’ as the theme, the festive rally started from the Shangshad Bhaban and ended at the Ban Bhaban. The Honorable Minister of Forest and Environment, Mr. Anwar Hossain Monju was the Chief Guest on the occasion.

Field Trip at Bangabandhu Safari Park, Gazipur
A day-long field trip was held at Bangabandhu Safari Park, Gazipur on April 04, 2014; Two NSSB members and 47 NDNSC members participated. The trip was supported by the Govt. Forest Department and was guided by Mr. Biplob Deb, Director, NDNSC and Life Member, NSSB. Mr. Stephen Don Sarker, Faculty, Dept. of Chemistry, Notre Dame College also participated the trip. Members observed the natural beauty of the Safari Kingdom, Core Safari Park, and made out a list of the Flora and Fauna under observation.

Report by – Salman Bin Sultan
Life Member, NDNSC &
Corporate Member, NSSB

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Environmental Governance – Perspective, Bangladesh

– Which the Country is struggling to Improve, despite its Legislative and Institutional Arrangement

Dr. Mohammad Tarikul Islam
Former UN Development Practitioner
Associate Prof., Dept. of Govt. & Politics, JU
Visiting Research Fellow, Univ. of Oxford, UK
Email. t.islam@juniv.edu

Introduction

Environmental governance is a concept in political ecology or environmental policy related to identifying the elements needed to achieve sustainability and resilience. It is entwined with different aspects of sustainable development and is crucial not only to the well-being of the people but also for their very survival, particularly for those who depend on natural resources and the environment to manage livelihood. A large number of social, economic, and political conflicts and issues are also linked to environmental resources. Environmental governance, well-thought-out as the expanded management of policies engaging social and environmental actors, intends to meet this crisis by combining the experience and knowledge of relevant social agents and institutions.

Understanding the Concept of Environmental Governance

Environmental governance has been defined in several ways: i) “The whole range of rules, practices and institutions related to the management of the environment in its different forms (conservation, protection, exploitation of natural resources, etc.)” ii) “All the processes and institutions, both formal and informal, that encompass the standards, values, behaviour and organizing mechanisms used by citizens, organizations and social movements as well as the different interest groups as a basis for linking up their interests, defending their differences and exercising their rights and obligations in terms of accessing and using natural resources and, iii) “the formal and informal institutions, rules, mechanisms and processes of collective decision-making that enable stakeholders to influence and coordinate their interdependent needs and interests and their interactions with the environment at the relevant scales[1].

At the international level, global environmental governance is “the sum of organizations, policy instruments, financing mechanisms, rules, procedures, and norms that regulate the processes of global environmental protection. Key principles of environmental governance are[2].

• Embeds the environment in all levels of decision-making and action.
• Conceptualizes cities and communities, economic and political life as a subset of the environment.
• Emphasizes the connection of people to the ecosystems in which they live.
• Promotes the transition from linear systems (like garbage disposal with no recycling) to circular systems.

Management, considered as the pluralist management of policies and social and environmental actors, intends to meet this crisis by pooling the experience and knowledge of each of the social agents and institutions concerned. The increasing scale and gravity of environmental problems in terms of climate change, loss of biological diversity and degradation of ecosystem services threaten to block any possible attempts at a solution by the various stakeholders, and are already restricting the prospect of economic development in many countries and region[3].

Environmental protection measures remain insufficient in the face of the warnings of the scientific community. The crisis related to environmental management causes by the accelerated and probably irrevocable impact of human activities on nature calls for collective responses by international institutions, governments, and citizens[4]. In order to facilitate for enforcement of environmental management, participation of relevant stakeholders across level has essence. At the local level, participation of all stakeholders (for example, NGOs, communities, local government, and the ministry of environment for the country in question) contributes to the success of an environmental management process, whilst the exclusion of some of these stakeholders makes it more difficult.

Milieu of environmental management in Bangladesh

Bangladesh is recognized to be one of the most ecologically vulnerable countries in the world, highly vulnerable to climate change as a result of its unique geographic location, hydro-geological characteristics like dominance of floodplains, low elevation from the sea and lastly the socio-economical characters like high population density, high levels of poverty, and overwhelming dependence on nature. The physical environment of Bangladesh is diverse, and there is a mix of both traditional and modern methods of land use, all very closely adapted to the heterogeneous conditions. This complexity of environment and utilization patterns has important implications for the vulnerability and depletion of the natural resource base. The high population density, low economic growth, lack of institutional infrastructure, an intensive dependence on agriculture and agricultural products, geographical settings, and various other factors, all contribute to make the country weak in its economic development and quality of life. Figure 1 & 2 below illustrates the disaster vulnerability of Bangladesh since it became an independent nation in 1971.

Figure-1: Disaster and climate profile of Bangladesh (UNDP Bangladesh, 2012)

Figure-2: Disaster calendar of Bangladesh (World Food Programme, 2011)

In line with the Stockholm mandate 1972, the government of Bangladesh actively participated in the generic process of protecting global environment. In order to put the Stockholm mandate into effect, the Bangladesh government had promulgated the first Water Pollution Control Ordinance in 1973 as well as the Environment Pollution Control Ordinance in 1977. To carry out the environmental programme on ground, in 1985 Department of Pollution Control Ordinance was established and it has been renamed and structured as Department of Environment (DOE) afterward.

The idea of environmental protection through national efforts was first recognized and declared with the adoption of the Environmental Policy 1992. While formulating environmental policy, different actors and factors played some direct and indirect roles. All the actors, whether external or internal, played pertinent roles in the formulation of the environmental policy. In the context of the environment, the Government of Bangladesh formulated an Environment Policy in 1992.  Key elements of the environment policy are maintenance of the ecological balance and overall progress and development of the country through protection and improvement of the environment; protection of the country against natural disasters; identification and regulation of all types of activities which pollute and degrade the environment.

The Government of Bangladesh has recognized climate change as an important issue and attempts are being made to incorporate potential response measures for reducing impacts of climate change into overall development planning process. It is being increasingly recognized that the adverse impacts of climate change in an already vulnerable country such as Bangladesh will put additional stress on overall development of the country. The National Adaptation Programme of Action (NAPA) is prepared by the Ministry of Environment and Forest (MoEFCC), Government of the People’s Republic of Bangladesh in 2005 as a response to the decision of the Seventh Session of the Conference of the Parties (COP7) of the United Nations Framework Convention on Climate Change (UNFCCC)[5].

The basic approach to NAPA preparation was along with the sustainable development goals and objectives of the country where it has recognized necessity of addressing environmental issue and natural resource management with the participation of stakeholders in bargaining over resource use, allocation, and distribution. Besides, to meet the threat of climate change by undertaking adaptation measures through utilization of internal and external resources, Bangladesh launched a Bangladesh Climate Change Strategy and Action Plan in 2009.

Formal responsibilities of overall environment sector are vested with the Ministry of Environment and Forest (MoEFCC). However, many other institutions, directly and indirectly, are involved in managing or shaping the environment sector. These embrace public sector, private sector, and civil society institutions. The MoEFCC bears the responsibility for working with other ministries to ensure that environmental concerns are given due recognition in their development program. The Ministry has an active role to play in policy advice and coordination of the implementation of action plans across all sectors. MoEFCC is also responsible for reviewing and monitoring the impact of development initiatives on the environment across all sectors.  Department of

Environment (DoE), one of the dedicated wings of MoEFCC is entrusted with the responsibilities of implementing environmental program on ground. Besides, other ministries of the government are tangled with a basis for addressing fundamental issues of environmental management in Bangladesh.

Challenges to Environmental Governance

Bangladesh’s top-down decision-making system, however, has its diffuseness as the central government makes decisions while local government and administration implement policies. The overall decision-making process is suffering from a dearth of feedback process from the lower to upper-levels, resulting in inadequate reflection of the actual ground-level situation in policies and systems. On the other hand, the decision-making process provides no adequate channels for communication among decision-makers, the public, relevant actors (civil society members and non-state actors) and the media. As a result, non-state actors show less interest in undertaking initiatives in responding to policies, and the community for whom environmental protection programs are designed does not play a positive role in participation that limit the effectiveness of implementation, largely[6].

Existing environmental policy guidelines don’t offer operative apparatuses to deal with climatic change; even environment policy did not mention explicitly the term climate change and its adverse impacts. Formal or informal dialogues between governmental agencies particularly MoEFCC and DoE as well as polluters are not witnessed in the process of environmental policy implementation in Bangladesh. Institutional capacity of the concerned ministries for implementing the various action measures is not passable.

Conversely, neither the fledgling MoEFCC nor DoE has developed the institutional capacity to extensively fight problems of environmental management and protection. Inadequacy in transparency and public consultation at decision-making process resulting in weakness of MoEFCC and DoE to care for environmental governance. In addition, there are a number of underlying causes which are apparently liable for poor environmental governance in Bangladesh, including a lack of institutional capabilities, untrained human resources, a lack of awareness, low community participation in resource management, and a paucity of research and lack of coordination among different stakeholders (governments, UN agencies, NGOs, private sector, and civil society).

The necessary reforms represent a slow process that requires time, energy, money and, above all, diplomatic negotiation. And a serious environmental crisis has proved incapable of generating a unanimous response from all countries. Persistent divisions are slowing down progress towards properly organized global environmental management. Like many other countries, common obstacles and challenges Bangladesh is facing for safeguarding environmental governance include:

• Environmental regulations seem ineffective due to lack of funding, imbalance, and absence of links with the economy, and the limited application of Multilateral Environment Agreements (MEAs)[7].
• Limited financial resources and insufficient direct investment in the environment are responsible for promotion of environmental management.
• Lack of coordination among different stakeholders (governments, UN agencies, NGOs, private sector and civil society) hinders the smooth application of management towards environmental issue. There is increasing recognition that environmental issues are interdependent, not only with development and with sustainable economic growth, but with trade, agriculture, health, peace and security. Despite this fact, there is no permanent cooperation with stakeholders addressing these issues/challenges in the developing countries.
• There is an imbalance between international environmental management and other international trade and finance programs.
• The lack of political will also prevents the environmental question being incorporated into the key domain of the macro economy, particularly in the World Trade Organization (WTO), whilst market forces continue to generate errors and distortions that speed up environmental degradation and make it difficult to apply environmental decisions. Global Environment Facility[8] (GEF) is not administered precisely to provide an avenue for the developing countries to cope with the challenges encountered due to climate change impact[9].

Way forward

To guarantee the achievability of all national policies relevant to environment, MoEFCC and DoE should adopt mitigation and adaptation process to build up central database and management information system (MIS). Existing environmental policy needs to be reformed with the climatic vulnerability considerations. Clear policy direction is essential to solve the trans-boundary water issues with India accelerating bilateral negotiations as well as uplifting the Joint River Commission. It is important to launch community awareness and information dissemination in order to have the stakeholders involved and concerned. These campaigns would also give the opportunity to understand what the perception and views of the public on environment, climate change, and adaptation are.

Changes in institutional, administrative, and organizational arrangements would be necessary to enhance the effectiveness of political decisions. This would be preceded by an examination of the existing bodies in charge of climate change issues: national climate change committees, their degree of representativeness and corresponding power and functions. Better coordination/integration of the different sectoral departments would be encouraged and institutionalized to render the services aiming at attaining governance for environmental protection. Efforts to be directed to find out possible way forward to ensure accountability and efficiency of the local government managing natural resources and environment.

Relevant stakeholders should also play a major role to streamline the environmental governance by the way of Information collection and dissemination; Policy development consultation; Policy implementation; Assessment and monitoring; and Advocacy for environmental justice. We should bear in mind that, NGOs and other civil society groups are not only stakeholders in governance, but also a driving force behind greater international cooperation through the active mobilization of public support for international agreements. Due to their critical role in service delivery and implementation, civil society organizations have long been recognized as “partners” of the UN system, especially in environmental negotiations. Above all, the United Nations system, including international finance and development agencies, and all intergovernmental organizations and forums should, in consultation with non-governmental organizations complement the efforts of the Government of Bangladesh to accelerate the enforcement of legislations pertaining to environmental governance.

N.B. –

1. This paper was previously appeared in LSE (London School of Economics and Political Science, UK) South Asia Blog.
2. Mohammad Tarikul Islam is a former UN Development Practitioner, and Associate Professor of Government and Politics at Jahangirnagar University in Bangladesh and Visiting Research Fellow at the University of Oxford, United Kingdom. He can be reached at :  islam@juniv.edu

References:

[1] Roussel Marie, Institutional Failures of the Global Environmental Management, (University of Adelaide: Australia, 2007), 45.

[2] L Tacconi, Developing environmental management research, (Environmental Conservation: London, 2011), 66.

[3] K Bakker, an uncooperative commodity: privatizing water in England and Wales (Oxford University Press: Oxford, 2004), 13.

[4]  MT Islam, Climate negotiations: how does Bangladesh fare? (LSE: London, 2018), 2.

[5]  MT Islam, des institutional pite legislative and arrangements, Bangladesh is struggling to improve environmental governance (LSE: London, 2018), 2.

[6]  MT Islam, despite legislative and institutional arrangements, Bangladesh is struggling to improve environmental governance (LSE: London, 2018), 3.

[7] A multilateral environmental agreement (MEA) is a legally binding agreement between three or more states relating to the environment. It is effective from 1972. They are predominantly produced by the United Nations. It is called a bilateral environmental agreement if the agreement is between two nation states.

[8] The Global Environment facility (GEF) GEF unites 182 countries in partnership with international institutions, civil society organizations (CSOs), and the private sector to address global environmental issues while supporting national sustainable development initiatives. Today the GEF is the largest public funder of projects to improve the global environment. An independently operating financial organization, the GEF provides grants for projects related to biodiversity, climate change, international waters, land degradation, the ozone layer, and persistent organic pollutants.

[9] UNEP, International Environmental Management and the Reform of the United Nations (UNEP: New York, 2008), 29.

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The Environmental Challenges
-Options for Sustainable Development in Bangladesh

Md. Oly Ullah Chowdhury
Lecturer in GED, 
Northern University Bangladesh
E.mail. olydu92@gmail.com

Introduction

The Environmental stability of human settlement now is an international concern; but since the Industrial Revolution in 1760 to the recent past, people have thought about the economic growth in almost all development strategies and programs. They exposed little concern about the environment that could be affected by taking such strategies and programs. That’s why the people have indiscriminately deforested and subsequently industrialized and modernized their habitations. Consequently, the level of greenhouse gases like, Carbon Di-oxide, Carbon Monoxide, Sulphur Di-oxide, Sulphur Monoxide, etc. have increased considerably. This resulted in the gradual disrupting the Eco-systems, especially food chains and food webs along with the rise of global tempreture. This situation is melting down the polar icebergs at an alarmingly higher rate and increasing the seawater level throughout the world. As a whole, the global environment and its biodiversity are under constant threat at present, and it is believed that two-thirds of the global wildlife may perish within the last decades of this century.

Bangladesh, as a developing country, should be more conscious and take responsibility for such environmental degradation and related natural disasters, to overcome its present vulnerable condition. Scientists have already predicted that a considerable part of Bangladesh’s coastal region may be submerged shortly due to the recurrent natural disasters like, Sidr, Aila, Bulbul etc. as well as situational problems like, inundation, drought, water logging, over-salinity, etc. Our coastal and low lying habitats are already threatened, despite all measures taken so far. So, we have to take sustainable initiative to resolve these problems immidiately. If such an initiative is not taken or delayed, the result will be even direr than the present. As Allah (ZS) has gracefully revealed in the Holy Quraan,“Struggle dominates on the terrestrial and aquatic environment, only due to human (evil) actions, that He (Allah) may make them taste a little part of that, which they have done themselves, so that they may get back (to good deeds). (Verse, 30:41)”.

Sustainable Development and Bangladesh

The term ‘Sustainable Development’ was first coined in a book written for the UN Stockholm Conference on Human Environment. Sustainable Development refers to organizing principles of development; the aim of it is to create an eco-friendly sustainable world for our future generations. According to Brundtland Report ‘Sustainable development is a development that meets the needs of the present without compromising the ability of the future generations to meet their own needs’ (UN, 1987). Many models have so far clarified the concept of sustainable development, of which the Four Sphere’s model is most conspicuous. According to it, for sustainable development, an environmental aspect cares about environmental protection, energy efficiency, use of natural resources, and environmental justice. If we consider the environmental aspects as the main concern, then our perambulation will be escalated in the Politics, Economics, Cultural Yard, and Society at large (Social Inclusion and Civil Rights. Sustainable development is possible if the social environment, economy, and politics are preferably related to the developmental work through the best use of natural energy.

If we consider environmental aspects to be a major concern, then our development in politics, the economy, the cultural arena, and the social arena (social inclusion and civil rights) will be further developed.

Four Spheres Model of Sustainable Development

The Intensity of Major Environmental Disasters in Dhaka

The atmosphere is a mixture of gases, predominantly N₂ (78.09%), O₂ (20.94%), Argon (0.93%), CO₂ (0.032%) and some other gases (less than 1%) (Shukla, R.S. and Chandel, P.S.2003). According to a World Bank report, Air pollution causes 15,000 deaths in Bangladesh each year. In 1995, the average Ozone absorption in Mexico City was about 0.15 parts per million, ten times of that of natural atmospheric absorption and twice the maximum permitted volume in Japan or United States. The density of lead in the air of Dhaka is 463 Nanograms per cubic meter, which is ten times more than the acceptable standard and many times more than the above-mentioned cities, even than the most polluted city – Mexico (Ahmed, Shakeel,2011). Now, the question is, why is the intensity of air pollution is more in a developing country like Bangladesh? One of the facts behind this is the  Exhaust fumes out of vehicles, burning of fossil fuels, such as coal, oil, or gas, harmful off-gassing from materials, such as paint, plastic production, and so on (Shukla, R.S. & Chandel, P.S.,2003). The national ambient air quality of Bangladesh and volume of pollutants in the air of Dhaka city are revealed below-

Source: Department of Environment (DOE), 1997

It is appraised that on an average, 870 million acre-feet of river water flows annually across our boundaries, the average amount of rainfall in the country is about 203 million acre-feet (Gain, Philip.,2002). The surface water of the country is vulnerable from untreated industrial sewage and municipal manures, excess pollution from chemical fertilizers and pesticides and oil, lubes emission in the coastal area from the operation of sea and river ports and ship breakage. The rivers that are sealed to Dhaka city like Buriganga, Turag, and Balu have contaminated more than the others have. The pollution spot near the Buriganga Third Bridge, releases a huge amount of toxic chemical waste out of Hazaribagh Tannery through Bashila Canal. There are about 149 tanneries in this area, which produce daily about 18,000 liters of melted and about 115 metric tons of solid wastes, most of which are released into the Turag river through Bashila and Katasur Canals (Binte Amin, Fahima,2015). According to Mott Macdonald International Ltd’s report of 2007, the total amount of solid waste generated every day in DCC area is about 7500 to 8000 tons. Another worst pollution spot is near the Tongi Bridge that originates massive pollutants loading from the Tongi Industrial Area. This industrial area retains about 29 heavy industries. This constellation of industries of the capital produces 7,159 kg wastes daily (Binte Amin, Fahima,2015).

Due to noise pollution, millions of people in Bangladesh have become susceptible to several health risks, ranging from deafness to cardiac arrests. On the streets of the city, noise pollution is a common scenario, initiated by hydraulic horns of vehicles, microphones, and cassette players (Islam, Sirajul. 2003). According to the World Health Organization (WHO), commonly 60 dB (decibel) sound can make a man deaf shortly and 100 dB sound can cause complete deafness.

According to the Noise Pollution (Control) Act 2006,

The noise level was above 130 dB at Farmgate, 120dB during daytime at Gabtoli, Arambagh intersection, Gulshan-2 intersection, Gulistan intersection, Mirpur 10 intersection, Banglamotor, New Market, Mascot Plaza of Uttara, and Jagannath University (DoE, 2006). It is seen that the noise level of the south parts of Dhaka City has become terrible, which is shown in the table.

The environmental degradation happens due to the unwise activities of people, which may sometime turn into a disaster. Earth-quake, landslide, soil erosion due to cutting of bank-vegetation, arbitrary destruction of forests, emissions of toxic gases and the release of toxic chemicals etc. are all anthropogenic disasters. According to FAO, there is left only 11.1% of forested land area in the total country. Bangladesh has lost an average 3.5% of forest land from 1990 to 2010. If this happens, then gradually the country will turn into a barren desert, which we are already observing in different parts of Rajshahi area. The country’s temperature has been increasing, at an unstable rate, resulting in recurrent natural disasters, earthquake, surge, tornedo, tidal bores etc., like – Sidr, Aila, Nargis, Phony, Bulbul etc.

Risk Reduction Strategy and Sustainable Development of Bangladesh

As a considerable period like 10 to 15 years is required to understand the Climatic condition and changes from the regular weather physiographic reports, to implement any correlated operation to save the environment of Bangladesh in a sustainable way, we need to plan for a long-term action policy.

Conservation of Biodiversity for Sustainable Development

Human beings, to a substantial magnitude are directly or indirectly dependant upon biodiversity for their existance. Due to the increase in population, urbanization, and industrialization, we are pushing the environment into an alarming threat. Since, it is almost impossible to recover whatever we have already lost due to our own actions, so our immediate task should be to protect the existing resources in a sustainable way for our future generations. Conservation of Biodiversity can be depicted with two methods: In-situ and Ex-situ conservation – (Shukla, R.S. & Chandel, P.S.,2003).

Supply Management and Sewage Disposal

Dhaka is recognized as one of the Mega cities in the developing countries of the world. Its population size is about 10 million and the population density (persons per sq. km) of greater Dhaka city is about 30,000. Though, for Small Income Community (LIC) people, the density upsurges to 220,000, which is more than 7 times paralleled to that of Dhaka city (A.Khan,Taqsem). In the city of such population density, there is almost no plan to remove man-made wastes. Most initiatives taken so far such as drains or conduit pumps to remove garbage are probably filled up with rigid wastes like polythene, plastic bag or sags, creating water logging at many parts of the city after a short time downpour. Worst of all, is the condition of river-water, which has being over-polluted. This is due the throwing of all sorts of rubbish into the river-water like – Buriganga, Turag etc. So, to get rid of such a curse, we have to take some long-term and sustainable action plans.

• To eradicate such problems, generally three methods are applied for sewage disposal like, Soaking pits, Septic tank, and Municipal sewage disposal plants. According to the requirements of the city, Bangladesh Govt. has to take proper initiatives to adopt anyone of those.
• The terminal releasing point of sewage systems of Dhaka city should be moderated for not to release the waste into the river, but should be recycled for re-use or burried deep into the soil for degradation.
• The existing drains in the city should be expanded and controlled through warnings to public, for not to release their household wastes/dirts directly into the drain, but in the supplied bins placed on certain pick up points.
• To create awareness among the people, publicity programs, seminars, symposia etc. can be organized, directly or through mass media and volunteers especially, young people should be engaged to propagte about health hazards and safety measures.

Human Movement and Environmental Sustainability

Replace, regulate, and restore model of pollution management

Govt. authorities, NGOs and the public need to commit together to achieve a sustainable environmental development. There are large number of NGOs in Bangladesh, who have to enroll for working for such development, like- framing of environmental policies, protecting endangered and vulnerable faunal or floral Species, mobilizing public volunteers and mass people for such sustainability. It is known that, the widespread use of gas, fuel, oil and other energy resources has been leading us towards global warming, which is mostly responsible for Climate change. So, in order to stop pollution here, we all must work together, hand in hand. A prescribed approach for such strategies can be taken from the following boxes, a model for anti-pollution campaign (Rutherford, Jill. 2009).

Meanwhile, the Bangladesh government has taken several steps to protect the environment, like- National strategy and action plan 2009, Organized with three other donor countries (Sweden, Denmark, UK), Bangladesh has launched a common trust fund from development partners to implement a long-term strategy, which is named as Bangladesh Climate Change Resilience Fund (BCCRF). The fund currently comprises of USD 125 million, and will be offered to finance the operation of the national strategy and action plan, within the following six supports:

• Food security, social protection and health,
• Comprehensive disaster management,
• Infrastructural development
• Research and knowledge management,
• Mitigation and low-Carbon development
• Capacity building and institutional strengthening

(SIDA, Common Donor fund will assist Bangladesh to adopt).

Concluding Remarks

Now, talks about Global warming and Climate change have been the sweltering issues around the world. Environmental scientists believe that already one-third of mammals, fishes, reptiles, and other animals have been extinct due to Climate change. In Bangladesh we have already been observing their impacts. One of the reasons is that, we ourself are pushing the environment towards such disasters, by burning fossil fuel, cutting down our forests, releasing hazardous gases like – CO₂, NO₂, CH₄, CFC, etc. In addition to government’s initiative to protect us from disasters and to make natural balance sustainable for the future generation, we need to realize the necessity of achieving an eco-friendly environment. In collaboration with the Govt., we have to strive hard in a scientific way to achieve our esteemed goal to achieve a balanced sustainable and livable environment especially in Bangladesh.

References:

1. Islamic Foundation Bangladesh, 2016. “Surah Rum Ayat No. 41: Al Quran-ul-Karim”. Dhaka: Efa publications.
2. UN, 1987. “Our Common Future: Brundtland Report: A World Commission on Environment and Development.”
3. Shukla, R.S. and Chandel, P.S.2003. Plant Ecology and Soil Science. India: Rajendra Ravindra Printers (Pvt.) Ltd, Ram Nagar, New Delhi-11005.
4. Ahmed, Shakeel. 2011. “Air Pollution Kills 15,000 Bangladeshis Each Year”. PATIMES: American Society for Public Administration. Available at: https://patimes.org/air-pollution-kills-15000-bangladeshis-each-year/.
5. Gain, Philip. 2002. Bangladesh Environment. Published by: Society for Environment and Development (SEHD), Lalmatia, Dhaka-1207.
6. Binte Amin, Fahima. 2015. “Water Pollution of most of the water source in Bangladesh” 24^th march 2015. Foreign Affairs Insights & Review (FAIR). Available at:http://fairBangladesh.net/about-fair/.
7. Islam, Sirajul. 2003. Banglapedia: National Encyclopedia of Bangladesh, Dhaka: Asiatic Society of Bangladesh.
8. DoE, 2006. Department of Environment, Government of the people’s Republic of Bangladesh.
9. Khan, Taqsem. “Dhaka Water Supply and Sewerage Authority: Performance and Challenges”. Dhaka WASA, Bangladesh.
10. Hassan, J.B.Alam . International Journal of Engineering Research and Applications (IJERA) ISSN: 2248-9622 , Vol. 3, Issue 2, March -April 2013, pp.1032-1040.
11. Rutherford, Jill. 2009. Environmental Systems and Societies, Oxford University Press, Oxford, New York.
12. 2014, “Common Donor fund will assist Bangladesh to adopt”.Department for Asia, North Africa and Humanitarian Assistance. Available at:https://www.sida.se/English/where-we-work/Asia/Bangladesh/examples-of results/Common-Donor-Fund-Will-Assist-Bangladesh-to-adapt/.

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Ecosystem Goods & Services (EG&S) in Bangladesh
-A Review of the unattended benefits of Natural Resources

Suriya Ferdous  
Postgraduate in Environmental Science 
National Consultant, Rio Conventions Project,
United National Development Program (UNDP), Bangladesh
Email. suriya.ferdous@gmail.com

Murtaza Khan Lodi
Postgraduate in Anthropology
Natural Resource Management and Organic Farming Specialist 
Email. murtaza.lodi@gmail.com

ABSTRACT

Majority of the world’s population depend on their surrounding landscapes for multiple ecosystem good and services (EG&S) that underpin their livelihoods. The utilization and values of EG&S from solar, air, water, food, medicine, raw materials, timber etc supply to biodiversity conservation towards sustainable development have set mutual phenomena across and within different settings to human society. Ecosystems, either for productive or protective purposes, also have the potential to mitigate land degradation, meet demand for environmental regulating services such as Carbon sequestration, water regulation and air filtration, and for cultural services such as recreation and spiritual values. With broad 05 types of ecosystem diversities further categorized in 25 bio-ecological and 30 agro-ecological zones, Bangladesh is provided boundless supplies of natural good and services from its geo-morphological setting, physiographic benefits and numerous biological diversities in forests, rivers, estuaries and marine. The importance and values of EG&S in Bangladesh have been in the centre of discussion and this is expected to continue with the alleviated growth of population and standard of living and as the crucial drivers for achieving the sustainable development goals.

INTRODUCTION

The importance and value of ecosystem goods and services are now widely acknowledged for its positive role in planet, people, and prosperity – three main pillars of sustainable development. The implication has been linked to policy and decision making as an innovative strategy for the improved management of land, water, and living resources that can promote conservation and at the same time fostering human well-being. Fair understanding of the connection and transfer between the EG&S and human and/or living beings is necessary for making the actual perception on the whys and wherefores the EG&S has no alternatives to the earth’s survival and sustaining. Terms of definitions below provide ideas of the nature, functions, and connectivity of different environmental units.

Environment[1]: includes water, soil, air, flora, fauna, and “all those elements which in their complex inter-relationships form the framework, setting and living conditions for mankind, by their very existence or by their impact”. Environment is defined by including

• Ecosystems and their constituent parts
• All natural and physical resources
• Social, economic, aesthetic, and cultural conditions which affect the environment or which are affected by changes to the environment.

Ecosystem[2]: The biotic community and the abiotic environment interact and function together as a system called the ecological system or ecosystem. The elements of abiotic (non-living environment) are air, water, soil, and the basic elements and compounds of the environment: climatic regime and physical factors (Temperature, Relative Humidity etc), inorganic substances (water, Carbon, Nitrogen, Sulphur, Phosphorus, etc), and organic substances (proteins, carbohydrates, lipids, etc). The biotic components are comprised of: producers (largely green plants), consumers (chiefly human and animals), and decomposers (mainly microorganisms like bacteria, fungi, etc).

Biological Diversity[3]: or biodiversity means the variability among living organisms from all sources including, inter alia, terrestrial, marine, and other aquatic ecosystems and the ecological complexes of which they are part: this includes diversity within Species, between Species and of ecosystems. Biodiversity is therefore, the sum of all life on our planet includes all the different Species of plants, animals and micro-organisms (Species diversity), all the genetic variability within these Species (genetic diversity) and all the diversity of the ecosystems formed by the different combinations of Species (ecosystem diversity). According to the Millennium Ecosystem Assessment project[4], biodiversity is a necessary underlying component of ecological goods and services, whereas biodiversity itself is also sometimes referred to as an actual EG&S.

These units of nature are intrinsically linked with one another collectively caters the constituents of sustainable environmental management and ensures human well-being at the end. This review article tends to briefly highlight the unattended services, goods, and drivers of the environment, which are valuably incorporated to the human benefits.

ECOSYSTEM GOODS & SERVICES – The Millennium Ecosystem Assessment has defined[5] Ecosystem Services as “the benefits people derive from ecosystems”. Besides providing services or goods like food, wood and other raw materials, plants, animals, fungi and micro-organisms provide essential regulating services such as pollination of crops, prevention of soil erosion and water purification, and a vast array of cultural services, like recreation and a sense of place. The ranges of natural environment and ecosystem resources are utilized as ecosystem goods and services for the sake of human benefits are presented below.

Key Ecosystem Goods and Services from natural resources

Ecosystems are also expected to play a key role in achieving recently adopted, global restoration targets such as the Bonn Challenge (to restore 150 million ha of degraded and deforested land by 2020)

Figure 2: Linkages between ecosystem and human well-being[6]

The New York Declaration on Forests as well as the objectives of Article 5 of the Paris Climate Change Agreement[7]. As a whole, ecosystems have the potential to provide a wide array of goods, services, ecological functions, as well as direct benefits to society and the environment. The linkages and translation between ecosystem structure, ecological function (including supporting services), and ecosystem services are highlighted in the following illustration.

ECOSYSTEM GOODS & SERVICES: BANGLADESH FACTS

On the basis of both biotic and abiotic components of ecosystems, the world is divided into five Global Ecological Domains and 20 Global Ecological Zones (GEZs). Bangladesh belongs to two of these zones, viz. Tropical Rain Forest GEZ (33%) and Tropical Moist Deciduous Forest GEZ (67%) of the Tropical Domain of the Global Ecological Domains. The central, north-eastern and south-eastern forests belong to Tropical Rain Forest GEZ[8].

Bangladesh is categorized under five broad Ecosystem Diversity[9]: Forest Ecosystem, Wetlands Ecosystem, Homestead Ecosystem, Coastal and Marine Ecosystem and Agro-ecosystem hosting 40 protected areas, 13 ecologically

Critical areas, and 25 bio-ecological zones[10]. The country is also living place of coastal and marine biodiversity with the estimated richness[11] as follows:

• 4,500 Species Invertebrates
• 3,733 plant Species
• 3,611 taxa of Angiosperms
• 706 Species birds representing 7.2% world’s bird population
• 442 Species Fish, 36 Species marine Shrimp
• 336 Species Mollusk – Snail, 03 Species Lobsters
• 100 Species migratory shore Birds and 76 sp. inland migratory Birds
• 42 Species Mammals, 35 Species Reptiles and 08 Species Amphibians
• 24 Species Snakes, 09 Species Dolphins, 03 Species Whales
• 16 Species Crabs, 03 Species Crocodiles
• 07 Species Tortoises, 168 Sea-weeds
• 03 Species Sponges, 03 Species Otters, 01 Species Porcupines

In line with the abovementioned key EG&S, Bangladesh enjoys marketed goods, materials and non-materials services from the vast natural capitals available in the country’s terrestrial and marine landscape. Natural capital[12], similar to the concept of economic capital, includes the natural environment and ecosystem resources, such as soils, forests, and wetlands that provide environmental assets and services essential to life. Examples of natural capital and the EG&S provided in the country is briefly shown in the following Table-1.

Table 1: Examples of Natural Capital and the EG&S Provided in Bangladesh

In accordance with the international development obligations and global target settings, Bangladesh has made series of big steps progressed fulfilling its commitment in protecting the ecosystems, existing richness in biodiversity, reducing environmental pollution, and thus ensuring sustainable development at community level. Major milestones of Bangladesh achieved by Bangladesh in response to the biological conservation are as follows:

• Inclusion of new Article 18A in the Constitution of the People’s Republic of Bangladesh articulated “ The State shall endeavor to protect and improve the environment and to preserve and safeguard the natural resources, bio-diversity, wetlands, forests and wild life for the present and future citizens”.
• Bangladesh is signed and ratified numbers of international Conventions and Protocols e.g. United National Convention for Biological Diversity (UNCBANGLADESH), Cartagena Protocol on Biosafety, Nagoya Protocol, Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES), Convention on the Conservation of Migratory Species of Wild Animals, World Heritage Convention, Ramsar Convention, United Nations Framework Convention on Climate Change (UNFCCC) and United Nations Convention to Combat Desertification (UNCCD).
• Bangladesh prepared the 1^st generation NBSAP in 2004 as per 2010 Biodiversity Targets and published the 2^nd generation NBSAP in 2016 as per Aichi Biodiversity Targets in compliance with the Article 6 of the UNCBANGLADESH in 1992 which called for an overarching framework for implementing the Convention through the development of National Biodiversity Strategy and Action Plans (NBSAP).
• Bangladesh submitted the Fifth National Report to the Convention on Biological Diversity (Biodiversity National Assessment 2015) in 2015.
• Bangladesh has enacted important Acts, Policies, and Rules related to Environment and biodiversity. Key instruments are:
  • Bangladesh Biological Diversity Act, 2017
  • National Environment Policy, 2017
  • Ecologically Critical Areas Management Rules, 2016
  • National Agricultural Policy, 2013
  • Bangladesh Biosafety Rules, 2012
  • Wildlife Protection and Security Rules, 2012
  • The National Water Policy, 1999
  • The National Fisheries Policy, 1998
  • The National Forestry Policy, 1994
• Bangladesh declared and managed ecological critical areas and protected areas and established the innovative livelihoods strategy such as community-based adaptation and mitigation, co-management etc.
• Bangladesh successfully implemented several technical high-value projects involving community participation such as National Capacity Development for Implementing Rio Conventions through Environmental Governance, Community Based Ecosystem Conservation, and Adaptation in Ecologically Critical Areas of Bangladesh (CBA-ECA Project), Integrated Protect Area Co-management, Community Based Eco-System Restoration in the Chattogram Hill Tracts and so on.

ASSESSMENT OF ECOSYSTEM GOODS AND SERVICES

Assessment of EG&S can serve many purposes[13], (i) raising clarity and awareness of the relative importance of the ecosystem to the government, policy makers, investors, non-governmental organizations and local communities, (ii) supporting new opportunities to link the natural resources with markets for identified goods and services, (iii) providing guidance for decision makers in understanding user preferences and relative values that people place on ecosystem services, (iv) generating information for designing new and modifying existing ecosystem so as to maximize their contributions to local communities, broader society and the global environment (v) informing land use planning and (vi) consolidating an efficient use of invested funds by identifying the means the EG&S can achieve greatest benefits.

The importance of the concept ‘ecosystem services’ was elevated by the publication of the Millennium Ecosystem Assessment (MA) in 2005, a work involving over 1300 scientists. A wide spectrum of methods has been proposed to assess the availability and use of provisioning ecosystem services. These include site-scale and landscape-scale modeling, biophysical observations, social-ecological patches and economic studies[14].

Under NBSAP Strategy-1: Recognize the value and importance of biodiversity, Bangladesh also conducted few assessments and valuations of the existing EG&S, mostly completed at project level. As for example, Economic valuations of different ecosystems e.g., Sundarban, Values of Protected Areas (PAs) as well as the documentation of biodiversity etc.

CONCLUDING CONSIDERATION

Although there are ecological, cultural and economic importance of these goods and services, the ecosystems and biodiversity are still being degraded and lost at an unprecedented scale. One major reason for this is that the value (importance) of ecosystems to human welfare is still underestimated and not fully recognized in every day planning, management and decision-making, in other words, the benefits of their services are not, or only partly, captured in conventional market economics. Valuation (assessment) can be done in different ways as valuation needs to be driven by local needs, by means of assessing the total contribution that ecosystems make to human well-being.

Standard operating procedure, certification of responsible ecosystem management is a demand of present age of Rio+20. Proper assessment of the EG&S and subsequent documentation, reliable monitoring, maintenance guarantee, embedded knowledge co-generation still call for effective actions from the government of Bangladesh. Inclusive and participatory monitoring of ecosystem goods and services may have a large potential, especially in local and data scarce environments where conventional data and knowledge generation practices may not be sufficient to support policy and practice. Participatory data and knowledge co-generation may not only support a better management of ecosystem but also their adaptive use for improving local livelihoods.

The magnitude of available EG&S in Bangladesh is close to unlimited; unfortunately, with the huge burden of bulging population in small country, the goods and services provided by the environment remained unattended. Consequently, pollution never ended, lands are still degraded, more Species enlisted as endangered, forest cover is lowered than the national mandatory requirements, and natural hazards occurred more frequent unprecedented. It’s a high time to call for another integrated environmental management action so that a long-lasting linkage among service provider (ecosystem) – provision (goods and services) – service receiver (individual) can be on place.

References:

[1] Ahmed S, Dr, 2018. Environment, Ecosystem, Biodiversity, Climate Change Issues and Management presentation made in the Training and Trainers on Rio Conventions, Dhaka, Bangladesh.

[2] Ahmed S, Dr, 2018. Environment, Ecosystem, Biodiversity, Climate Change Issues and Management presentation made in the Training and Trainers on Rio Conventions, Dhaka, Bangladesh.

^[3]  DoE, 2018. Training Module on Rio Conventions, Rio Project, Department of Environment (DoE), Ministry of Environment and Forests (MoEFCC).

[5]https://www.iucn.org/commissions/commission-ecosystem-management/our-work/cems-thematic-groups/ecosystem-services data taken on 28 April 2018.

[6] Illustrated by the Author with inspiration from collection sources: Jennifer T. et al, 2017. Incorporating ecosystem services into environmental management. Volume 137, March 2017, Pages 486-503; and Ahmed S, Dr, 2018. Environment, Ecosystem, Biodiversity, Climate Change Issues and Management presentation made in the Training and Trainers on Rio Conventions, Dhaka, Bangladesh

[7] Himlal Barala, C, Manuel R., Guariguatab, Rodney J. Keenanc, 2016. A proposed framework for assessing ecosystem goods and services from planted forests. Ecosystem Services 22 (2016) 260–268, Elsevier.

[8] Department of Environment, 2015. the Fifth National Report of Bangladesh to the Convention on Biological Diversity. Department of Environment, Ministry of Environment and Forests, Government of the Peoples Republic of Bangladesh.

[9] https://www.thebangladesh.net/bio-ecological-zones-of-bangladesh.html#info data taken on 26 April 2018.

[10] Nishat, A., S.M. Huq, B. Imamul., P. Shuvashish, A.A.H.M Reza, and M.A.S. Khan (eds.), 2002. Bio-ecological Zones of Bangladesh. IUCN Bangladesh Country Office. Dhaka, Bangladesh.

[11] Ahmed S, Dr, 2018. Environment, Ecosystem, Biodiversity, Climate Change Issues and Management presentation made in the Training and Trainers on Rio Conventions, Dhaka, Bangladesh. and  Department of Environment, 2015. the Fifth National Report of Bangladeshto the Convention on Biological Diversity. Department of Environment, Ministry of Environment and Forests, Government of the Peoples Republic of Bangladesh.

[12]https://www.gov.mb.ca/agriculture/environment/ecological-goods-and-services/index.html data taken on 25 April 2018

[13] Himlal Barala, C, Manuel R., Guariguatab, Rodney J. Keenanc, 2016. A proposed framework for assessing ecosystem goods and services from planted forests. Ecosystem Services 22 (2016) 260–268, Elsevier.

[14] Laura Vang Rasmussen, Ole Mertz, Andreas E. Christensen, Finn Danielsen, Neil Dawson, Pheang Xaydongvanh, 2016. A combination of methods needed to assess the actual use of provisioning ecosystem services Ecosystem Services 17 (2016) 75–86.}]

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মিলিবাগ

– আজহারুল ইসলাম।

মিলিবাগ; ছবিঃ সংগৃহীত।

যারা গাছপালা পছন্দ করেন তারা নিশ্চয়ই মিলিবাগের সাথে পরিচিত আছেন। এটা একধরনের পোকা যার আক্রমনে উদ্ভিদের অনেক ক্ষতি সাধন হয়। এরা সাধারনত সিস্টের চারিপাশে তুলার মত একটা আবরন তৈরি করে ফলে অনেক রকম পেস্টিসাইড ব্যবহার করেও আশানুরূপ ফলাফল পাওয়া যায়না।

আমরা গাছের পাতায় ও ডালপালায় যে ধরনের মিলিবাগ দেখতে পাই তা হলো স্ত্রী পোকা এরা এক স্থান থেকে অন্য স্থানে চলাফেরা করতে পারেনা। পুরুষ মিলিবাগ উড়ে বেড়াতে পারে সুতরাং এরা গাছের সুবিধা জনক স্থানে বসে স্ত্রী মিলিবাগ কে ক্যামিকেল সিগনাল পাঠিয়ে বলে এখানে প্রচুর খাবার আছে তুমি চলে এসো কিন্তু স্ত্রী মিলিবাগ তখন এই সিগনালে সাড়া দিতে পারে না যেহেতু এরা চলাচলে অক্ষম।

পুরুষ মিলিবাগের এই সিগনাল এক ধরনের কালো পিঁপড়ার এন্টিনায় ধরা পড়ে ও তাৎক্ষনিক ভাবে এরা মিলিবাগের সংষ্পর্শে ছুটে গিয়ে দুজনে সিমবায়োটিক বুঝাপড়া সেরে নেয়। কিছু শর্ত সাপেক্ষে পিঁপড়া বাহক হিসেবে স্ত্রী মিলিবাগকে পুরুষ মিলিবাগের কাছে পৌঁছে দেয়। বিনিময়ে মিলিবাগ খাবার গ্রহন করার পর তাদের মিষ্টি বিষ্ঠা গুলো পিঁপড়াকে ভক্ষন করতে দেয়। এভাবেই চলতে থাকে এদের লাইফ সাইকেল। সুতরাং যেখানেই মিলিবাগের আক্রমন সেখানেই পিঁপড়ার আনাগোনা দেখা যায়।

মিলিবাগের আক্রমন হতে বাঁচতে হলে এর বাহন পিঁপড়া ধ্বংশ করতে হবে অথবা এদের যাত্রা পথে ব্যারিকেড দিতে হবে তাহলে আপনার প্রিয় উদ্ভিদকে এদের আক্রমণ থেকে রক্ষা করতে পারবেন। এছাড়া মিলিবাগ আক্রান্ত গাছে প্রথম জোরে পানি স্প্রে করে এদের সিস্টের চারপাশে সৃষ্ট তুলার মত আবরন সরিয়ে দিয়ে আধা ঘন্টা পর পেস্টিসাইড স্প্রে করলে আশানুরূপ ফলাফল পাওয়া যাবে।

মিলিবাগ; ছবিঃ সংগৃহীত।

ছবিঃ সংগৃহীত।

The post মিলিবাগ appeared first on NSSB.

Anticancer Activities of  Nigella sativa (Black Cumin)
– A Devine gift for a Cancer-free World

Md. Asaduzzaman Khan
Dept. of Biochemistry, School of Biological Sc. & Technology
Central South Univ., Changsha, Hunan 410013, P R China
The Research Center of Preclinical Medicine, South-west Medical Univ., Luzhou, Sichuan  646000, P R China
Life Member, NSSB
asadkhanbmj@yahoo.com

Han-chun Chen
Dept. of Biochemistry, School of Biological Sc. & Technology
Central South Univ., Changsha, Hunan 410013, P R China
chenhanchun@mail.csu.edu.cn

Mousumi Tania
Dept. of Biochemistry, School of Biological Sc. & Technology
Central South Univ., Changsha, Hunan 410013, P R China

Dianzheng Zhang
Dept. of Biochemistry/Molecular Biology,
Philadelphia College of Osteopathic Medicine, Philadelphia, PA  19131, USA

Abstract

The Black Cumin (Nigella sativa) has been used as traditional medicine for centuries. The crude oil and thymoquinone (TQ) extracted from its seeds and oil is effective against many diseases like cancer, cardiovascular complications, diabetes, asthma, kidney disease etc. It is effective against cancer in blood system, lung, kidney, liver, prostate, breast, cervix, skin with much safety. The molecular mechanisms behind its anticancer role is still not clearly understood, however, some studies showed that TQ has antioxidant role, and it improves body’s defense system; induces apoptosis and controls Akt pathway. Although the anti-cancer activity of N. sativa components was recognized thousands of years ago but proper scientific research with this important traditional medicine is a history of last 2-3 decades. There are not so many research works done with this important traditional medicine and very few reports exist in the scientific database. In this article, we have summarized the actions of TQ and crude oil of N. sativa against different cancers with their molecular mechanisms.

Key words: Traditional medicine, Nigella sativa, Thymoquinone, Antioxidant, Anti-cancer mechanism

Introduction

Cancer is one of the major threats of modern life, which is considered as the second cause of death after myocardial infarction (Grundy, 1991). Millions of people die every year in different types of cancer despite tremendous efforts to find methods of control and cure. In the last century great advances have made in modern medical science to control disease. But many diseases like cancers are not yet curable fully. To find out new and authentic therapies, scientists are working with traditional or folk medicines in parallel of modern medicine. Nigella sativa has been used for medicinal purposes for centuries. It has been originated from Southeastern Asia and also used in ancient Egypt, Greece, Middle East and Africa. In Islam, it is regarded as one of the greatest forms of healing medicine available (Nigella-sativa-research.com, 2010; Wikipedia, 2010). It is a flowering plant, of which seed is used as a spice. The seed is called black cumin in English, while in old Latin it was called as ‘Panacea’ meaning ‘cure all’; in Arabic it is termed as ‘Habbah Sawda’ or ‘Habbat el Baraka’ translated as ‘Seeds of blessing’. It is also known as ‘Kalo jeera’ (in Bangladesh), ‘Kalonji’ (in India) and ‘Hak Jung Chou’ in (China) (Aggarwal et al., 2008). Both seeds and oil extracted from this plant are used in medicinal purposes.

The active ingredients of N. sativa have beneficial effects against many diseases, including cancers. For example, it is effective in the diminishing the risk of atherosclerosis  by decreasing the serum low density lipoprotein cholesterol level and increasing the serum high density lipoprotein cholesterol levels (Dahri et al., 2005; Nader et al., 2010); it exerts therapeutic and protective effect in diabetes by decreasing morphological changes and preserving pancreatic beta-cell integrity (Kanter et al., 2009) and by beneficially changing the hepatic enzyme activities (Pari and Sankaranarayanan, 2009); it is effective against hypertension (Khattab and Nagi, 2007; Dehkordi and Kamkhah, 2008); it has a potent antihistaminic effect on airways of asthmatic patients (Boskabady et al., 2010); its components are promising agents to complement Schistosomiasis specific treatment (El Shenawy et al., 2008); its oil protects kidney tissue against oxygen free radicals, preventing renal dysfunction and morphological abnormalities (Bayrak et al., 2008; Uz et al., 2008; Ragheb et al., 2009). For thousands of year, the seeds, oils and extracts of N. sativa have been used as an anticancer agent by Unani, Ayurveda and the Chinese system of medicine that have originated from the Arab, Ind-Bangla and China, respectively. The modern scientific research with the investigation of anticancer activity of N. sativa is comparatively recent affair (for the last 2-3 decades). There are not so many research works done in this field and very few review articles exist in this area. We have searched the scientific databases like Pubmed, Web of Science, and Google scholar and summarized the current scientific information about the anticancer activities of N. sativa with mechanisms of action.

Role of N. sativa as an anticancer agent

Many active ingredients have been found in the seeds of N. sativa. The seeds contain both fixed and essential oils, proteins, alkaloids and saponin (Ali and Blunden, 2003). Ghosheh et al. (1999) described the quantification of four pharmacologically important components: thymoquinone (TQ), dithymoquinone (DTQ), thymohydroquinone (THQ), and thymol (THY), in the oil of N. sativa seed by HPLC. Much of the biological activities of the seeds have been shown to be due to thymoquinone, the major component of the essential oil, which is also present in the fixed oil (Ali and Blunden, 2003). TQ is considered as potent anti-oxidant (Badary et al., 2003), anti-carcinogenic and anti-mutagenic agent (Bourgou et al., 2008; Khader et al., 2010) (structure of thymoquinone is shown in Figure 1a). Moreover, TQ is a relatively safe compound, particularly when given orally to experimental animals (Al-Ali et al., 2008). Alpha (α)-hederin, a pentacyclic triterpene saponin (structure: Figure 1b) isolated from the seeds of N. sativa, was also reported to have potent in vivo antitumor activity (Swamy and Huat, 2003).

 Figure 1. Chemical structure of anti-tumor agents isolated from N. sativa.
(a) Thymoquinone (source: PubChem-CID 10281),
(b) Alpha-hederin (source: PubChem- CID 73296)

(a) Thymoquinone (source: PubChem-CID 10281)

(b) Alpha-hederin (source: PubChem- CID 73296)

Sativa seeds or oils or its active ingredients like TQ are effective against different cancers:

Blood Cancer

El-Mahdy et al. (2005) reported that TQ exhibits anti-proliferative effect in human myeloblastic leukemia HL-60 cells. Derivatives of TQ bearing terpene-terminated 6-alkyl residues were tested in HL-60 cells and 518A2 melanoma by Effenberger et al. (2010). They found the derivatives induce apoptosis associated with DNA laddering, a decrease in mitochondrial membrane potential, and a slight increase in reactive oxygen Species. Swamy and Huat (2003) observed that α-hederin also induced death of murine leukemia P388 cells by a dose- and time-dependent increase in apoptosis.

Breast Cancer

Aqueous and alcohol extracts of N. sativa were found to be effective in vitro in inactivating MCF-7 breast cancer cells (Farah and Begum, 2003). N. sativa, in combination with melatonin and retinoic acid reduced the carcinogenic effects of DMBA (7, 12-di-methylbenz(a)anthracene) in  mammary carcinoma of rats (El-Aziz et al., 2005). Terpene-terminated 6-alkyl residues of TQ were tested in MCF-7/Topo breast carcinoma by Effenberger et al. (2010). They found the derivatives inducing cell death by apoptosis.

Colon Cancer

Gali-Muhtasib et al. (2004) suggested that TQ is anti-neoplastic and pro-apoptotic against colon cancer cell line HCT116. Salim and Fukushima (2003) demonstrated that the volatile oil of N. sativa has the ability to inhibit colon carcinogenesis of rats in the post-initiation stage, with no evident adverse side effects. Norwood et al. (2006) suggested TQ as chemotherapeutic agent on SW-626 colon cancer cells, in potency, which is similar to 5-flurouracil in action. However, on HT-29 (colon adenocarcinoma) cell, no effect of TQ was found (Rooney and Ryan, 2005).

Pancreatic Cancer

Chehl et al. (2009) showed that TQ, the major constituent of N. sativa oil extract, induced apoptosis and inhibited proliferation in PDA (pancreatic ductal adenocarcinoma) cells. They also suggested TQ as a novel inhibitor of pro-inflammatory pathways, which provides a promising strategy that combines anti-inflammatory and proapoptotic modes of action. TQ also can abrogate gemcitabine- or oxaliplatin-induced activation of NF-kappa B, resulting in the chemosensitization of pancreatic tumors to conventional therapeutics (Banerjee et al., 2009). The high molecular weight glycoprotein mucin 4 (MUC4) is aberrantly expressed in pancreatic cancer and contributes to the regulation of differentiation, proliferation, metastasis, and the chemoresistance of pancreatic cancer cells. Torres et al. (2010) evaluated the down-regulatory effect of TQ on MUC4 in pancreatic cancer cells. But in a study, Rooney and Ryan (2005) did not find any preventive role of TQ on MIA PaCa-2 (pancreas carcinoma) cells.

Hepatic Cancer

The cytotoxic activity of N. sativa seed was tested on the human hepatoma HepG2 cell line by Thabrew et al. (2005), and 88% inhibitory effect on HepG2 was found after 24-hour incubation with different concentrations (0-50 mg/ml) of the N. sativa extract. Nagi and Almakki (2009) reported that oral administration of TQ is effective in increasing the activities of quinone reductase and glutathione transferase and makes TQ a promising prophylactic agent against chemical carcinogenesis and toxicity in hepatic cancer

Lung Cancer

Swamy and Huat (2003) mentioned the antitumor activity of α-hederin from N. sativa against LL/2 (Lewis Lung carcinoma) in BANGLADESHF1 mice. Also, Mabrouk et al. (2002) showed that supplementation of diet with honey and N. sativa has a protective effect against MNU (methylnitrosourea)-induced oxidative stress, inflammatory response, and carcinogenesis in lung, skin and colon. However, Rooney and Ryan (2005) reported that α-hederin and TQ, the two principal bioactive constituents of N. sativa enhance neither cytotoxicity nor apoptosis in A549 (lung carcinoma), HEp-2 (larynx epidermoid carcinoma) cells.

Skin cancer

Topical application of N. sativa extract inhibited two-stage initiation / promotion [dimethylbenz [a] anthracene (DMBA)/croton oil] skin carcinogenesis in mice. Again, intraperitoneal administration of N. sativa (100 mg/kg body wt) 30 days after subcutaneous administration of MCA (20-methylcholanthrene) restricted soft tissue sarcomas to 33.3% compared with 100% in MCA-treated controls (Salomi et al., 1991).

 
Fibrosarcoma

TQ from N. sativa was administrated (0.01% in drinking water) one week before and after MCA treatment significantly inhibited the tumor incidence (fibrosarcoma) and tumor burden by 43% and 34%, respectively, compared with the results in the group receiving MCA alone. Moreover, TQ delayed the onset of MCA-induced fibrosarcoma tumors. Also in vitro studies showed that TQ inhibited the survival of fibrosarcoma cells with IC50 of 15 mM (Badary and Gamal, 2001). Oil of N. sativa also decreased the fibrinolytic potential of the human fibrosarcoma cell line (HT1080) in vitro (Awad, 2005).

Renal Cancer

Khan and Sultana (2005) reported the chemo-preventive effect of N. sativa against ferric nitrilotriacetate (Fe-NTA)-induced renal oxidative stress, hyper-proliferative response, and renal carcinogenesis. Treatment of rats orally with N. sativa (50 -100 mg/kg body wt) resulted in significant decrease in H₂O₂ generation, DNA synthesis, and incidence of tumors.

Prostate Cancer

TQ, from N. sativa, inhibited DNA synthesis, proliferation, and viability of cancerous (LNCaP, C4-B, DU145, and PC-3) but not non-cancerous (BPH-1) prostate epithelial cells by down-regulating AR (androgen receptor) and E2F-1 (a transcription factor) (Kaseb et al., 2007). In this study, they suggested TQ as effective in treating hormone-sensitive as well as hormone-refractory prostate cancer. Yi et al. (2008) found that TQ blocked angiogenesis in vitro and in vivo, prevented tumor angiogenesis in a xenograft human prostate cancer (PC3) model in mouse, and inhibited human prostate tumor growth at low dosage with almost no chemotoxic side effects. Furthermore, they observed that endothelial cells were more sensitive to TQ-induced cell apoptosis, cell proliferation, and migration inhibition compared with PC3 cancer cells. TQ also inhibited vascular endothelial growth factor-induced extracellular signal-regulated kinase activation but showed no inhibitory effects on vascular endothelial growth factor receptor 2 activation.

Cervical Cancer

Shafi et al. (2009) reported that methanol, n-Hexane, and chloroform extracts of N. sativa effectively killed HeLa (human epithelial cervical cancer) cells by inducing apoptosis. Effenberger et al. (2010) tested terpene-terminated 6-alkyl residues of TQ on multidrug-resistant KB-V1/Vb1 cervical carcinoma and found the derivatives inducing cell death by apoptosis.

Molecular mechanisms of N. sativa action against cancer

Cancers are the abnormal cell growth caused by genetic alteration. So, any agent which has anti-cancer activity, either protect genetic material from alteration or kill the genetically altered cancer cells. The active ingredients (mainly TQ) from N. sativa act on cancer cell to help to kill them by several molecular pathways.

El-Mahdy et al. (2005) suggested the apoptotic mechanisms behind the anti-proliferative effect of TQ (from N. sativa) on myeloblastic leukemia HL-60 cells. They reported that TQ induces apoptosis, disrupts mitochondrial membrane potential, and triggers the activation of caspases 8, 9 and 3 in HL-60 cells. The apoptosis induced by TQ was inhibited by a general caspase inhibitor, z-VAD-FMK; a caspase-3-specific inhibitor, z-DEVD-FMK; as well as a caspase-8-specific inhibitor, z-IETD-FMK. Moreover, the caspase-8 inhibitor blocked the TQ-induced activation of caspase-3, PARP cleavage and the release of cytochrome c from mitochondria into the cytoplasm. In addition, TQ treatment of HL-60 cells caused a marked increase in Bax/Bcl2 ratios due to upregulation of Bax and downregulation of Bcl2 proteins. Their results indicated that TQ-induced apoptosis is associated with the activation of caspases 8, 9 and 3, with caspase-8 acting as an upstream activator and activated caspase-8 initiates the release of cytochrome c during TQ-induced apoptosis. TQ action was also found as pro-apoptotic against colon cancer cell line HCT116 (Gali-Muhtasib et al., 2004). It was showed that the apoptotic effects of TQ are modulated by Bcl-2 protein and are linked to and dependent on p53. TQ also down-regulates the expression of NF-kappa B-regulated antiapoptotic (IAP1, IAP2, XIAP Bcl-2, Bcl-xL, and survivin) gene products (Sethi et al., 2008). Torres et al. (2010) found TQ inducing apoptosis by the activation of c-Jun NH(2)-terminal kinase and p38 mitogen-activated protein kinase pathways in pancreatic cancer cell.

TQ has also been reported to be active in controlling Akt pathway. Yi et al. (2008) found that TQ effectively inhibited human umbilical vein endothelial cell migration, invasion, and tube formation by suppressing the activation of AKT and extracellular signal-regulated kinase. Xuan et al. (2010) found that LPS  (lipopolysaccharides: a bacterial component)-induced phosphorylation of prosurvival kinases Akt and ERK1/2 was abrogated by TQ in dendritic cells.

NF-kappa B plays a key role in regulating the immune response, and incorrect regulation of NF-kappa B has been found to be linked to cancer (Albensi and Mattson, 2000). Sethi et al. (2008) found that TQ suppressed tumor necrosis factor-induced NF-kappa B activation in a dose- and time-dependent manner and inhibited NF-kappa B activation induced by various carcinogens and inflammatory stimuli. The suppression of NF-kappa B activation is correlated with sequential inhibition of the activation of I kappa B alpha kinase, I kappa B alpha phosphorylation, I-kappa-B-alpha degradation, p65 phosphorylation, p65 nuclear translocation, and the NF-kappa B-dependent reporter gene expression. Also Oberg et al. (2009) reported that a herbal melanin (HM) from N. sativa modulates cytokine production and suggested it as a ligand for TLR4 (toll-like receptor 4). They investigated the possibility that the HM-induced cytokine production is via an NF-kappa B signaling pathway and found that HM induced the degradation of I kappa B-alpha, a key step in the activation of NF-kappa B. Moreover, addition of I kappa B kinase (IKK) specific inhibitors effectively inhibited the observed HM-induced production of IL-8 and IL-6 by TLR4-transfected HEK293 (embryonic kidney 293) cells and THP-1 (Human acute monocytic leukemia) cells (Oberg et al., 2009).

Many studies showed that N. sativa oil or TQ has antioxidant activity and increases the activities of antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT) glutathione peroxidase (GPx) etc (Ebru et al., 2008; Barron et al., 2008; Ismail et al., 2010). And antioxidant enzymes are clearly related to cancer- mostly their increased activities are beneficial against different types of cancer (Khan et al., 2010). Administration of N. sativa oil or TQ can lower the toxicity of other anti-cancer drugs. In addition to these cancer inhibiting properties, components of N. sativa have cancer protective roles. Ibrahim et al. (2008) reported that N. sativa oil administration has a protective effect against the CCl₄-mediated suppression of CYP (drug-metabolizing cytochrome P450 enzymes). And genetic abnormalities and polymorphisms of CYP enzymes are associated with cancer (Sim and Ingelman-Sundberg, 2006; Chen et al., 2008). Radiotherapy is one of the most common strategies for treating human cancers but this treatment is somehow risky for normal tissue. Cemek et al. (2006) showed that N. sativa and glutathione treatment significantly antagonize the effects of radiation. Therefore, N. sativa may be a beneficial agent in protection against ionizing radiation-related tissue injury. Assayed (2010) investigated the radio-protective potential of N. sativa crude oil against hemopoietic adverse effects of gamma irradiation. He found that irradiation resulted in significant reduction in hemolysin antibodies titers and delayed type hypersensitivity reaction of irradiated rats, in addition to significant leukopenia and significant decrease in plasma total protein and globulin concentration and depletion of lymphoid follicles of spleen and thymus gland. Furthermore, there was a significant increase in malondialdehyde concentration with a significant decrease in plasma GPx, CAT and erythrocyte SOD activities. But oral administration of N. sativa oil before irradiation considerably normalized all the above-mentioned criteria; and produced significant regeneration in spleen and thymus lymphoid follicles. Thus N. sativa oil is recognized as a promising natural radio-protective agent against immunosuppressive and oxidative effects of ionizing radiation.

Figure 1: Possible mechanisms of thymoquinone (TQ) action

(1) TQ induces apoptotic cell death in cancerous tissues by up-regulating expression of apoptotic genes (caspases and bax) and down-regulating expression of anti-apoptotic genes (e.g., bcl 2); (2) TQ suppresses Akt activation by dephosphorylation and thus blocks cancer cell survival; (3) TQ deactivates NF-kappa B pathway by inducing cytokine production, and thus control oncogenic expression; (4) TQ increases the activities of antioxidant enzymes and protects cell against cancer; (5) TQ protects normal cells’ injury caused by ionizing radiation in the treatment of cancer; (6) TQ prevents CYP450 enzymes from damage. ‘+’ indicates increasing effect and ‘-’ indicates decreasing effect.

Concluding remarks

The anti-cancer activities of N. sativa components were recognized thousands of years ago but proper scientific research with this important traditional medicine is a very recent story. More research works should be emphasized behind this because it is a safe and promising anticancer agent. Specially, researchers should investigate the active ingredients more broadly, because, there is very few authentic reports about the chemical composition of seeds or oil of N. sativa exist. Also, the exact molecular mechanisms of thymoquinone and other components on different cancers should be investigated with more emphasize because current understandings are mostly unclear. For example, it is reported that N. sativa oil can protect cells from radiation, but the molecular mechanisms behind this is not properly understood. Currently, in some parts of the world, there is a renaissance of interest in traditional remedies. Many investigators now believe that traditional medicine is a promising source of new therapeutics against cancer. Extensive research with N. sativa may contribute to the discovery of new anticancer strategies.

[This article was first published in Afr J Tradit Complement Altern Med. (2011) 8(S):226-232]

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30.   Ismail, M., Al-Naqeep, G. and Chan, K.W. (2010). Nigella sativa thymoquinone-rich fraction greatly improves plasma antioxidant capacity and expression of antioxidant genes in hypercholesterolemic rats. Free Radic. Biol. Med., 48: 664-672.

31.   Kanter, M., Akpolat, M. and Aktas, C. (2009). Protective effects of the volatile oil of Nigella sativa seeds on beta-cell damage in streptozotocin-induced diabetic rats: a light and electron microscopic study. J. Mol. Histol., 40: 379-385.

32.   Kaseb, A.O., Chinnakannu, K., Chen, D., Sivanandam, A., Tejwani, S., Menon, M., Dou, Q.P. and Reddy, G.P. (2007). Androgen receptor and E2F-1 targeted thymoquinone therapy for hormone-refractory prostate cancer. Cancer Res., 67: 7782-7788.

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36.   Khattab, M.M. and Nagi, M.N. (2007). Thymoquinone supplementation attenuates hypertension and renal damage in nitric oxide deficient hypertensive rats. Phytother. Res., 21: 410-414.

37.   Mabrouk, G.M., Moselhy, S.S., Zohny, S.F., Ali, E.M., Helal, T.E., Amin, A.A. and Khalifa, A.A. (2002). Inhibition of methylnitrosourea (MNU) induced oxidative stress and carcinogenesis by orally administered bee honey and Nigella grains in Sprague Dawely rats. J. Exp. Clin. Cancer Res., 21: 341-346.

38.   Nader, M.A., el-Agamy, D.S. and Suddek, G.M. (2010). Protective effects of propolis and thymoquinone on development of atherosclerosis in cholesterol-fed rabbits.  Arch. Pharm. Res., 33: 637-643.

39.   Nagi, M.N. and Almakki, H.A. (2009). Thymoquinone supplementation induces quinone reductase and glutathione transferase in mice liver: possible role in protection against chemical carcinogenesis and toxicity. Phytother. Res., 23: 1295-1298.

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41.   Norwood, A.A., Tan, M., May, M., Tucci, M. and Benghuzzi, H. (2006). Comparison of potential chemotherapeutic agents, 5-fluoruracil, green tea, and thymoquinone on colon cancer cells. Biomed. Sci. Instrum., 42: 350-356.

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43.   Pari, L. and Sankaranarayanan, C. (2009). Beneficial effects of thymoquinone on hepatic key enzymes in streptozotocin-nicotinamide induced diabetic rats. Life Sci., 85: 830-834.

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Covid-19 Pandemic: What we know till now?

Md. Asaduzzaman Khan, PhD
Investigator / Scientific Professor,
Key Laboratory of Epigenetics and Oncology,
The Research Center for Preclinical Medicine,
Southwest Medical University, Luzhou, Sichuan, China.
E-mail: asadkhan@swmu.edu.cn / asadkhanbmj@yahoo.com,
Phone: +8619111859312 (CN), +8801984199420 (BD) 

The novel corona virus outbreak from Wuhan city (in December 2019) has become pandemic, and till 4th April, the official death toll reached nearly 60000 worldwide, while the total number of cases crossed one million [1]. The number of cases and death might be much higher, as most of the developing and underdeveloped countries are unable to test this virus and the related deaths are not counted.

Officially this virus has been named as ‘SARS-CoV-2’or ‘Covid-19’. In recent history, this Covid-19 pandemic has become the most deadly disaster, and in fact the world has never experienced such pandemic, where most of the countries have sealed their borders and all the global programs have been postponed, which affected business, economy, academia, sports, entertainment etc. worldwide.

The first Covid-19 case been reported in Wuhan city of China, which was found to be linked with a sea food market and wild animal food market. Initially it was thought that the virus had been transmitted to human from snake, but later scientists indicated that pangolin might be the carrier to transfer to human. The world health organization (WHO) indicates Covid-19 as of unknown etiology.

As usual, the politicians throughout the world started playing the blame game. USA blamed China (that they were making Biological weapon, and Covid-19 was a leakage), and China blamed USA-Israel (that they sent biological weapons to China through military). But what science says, is, “No, the coronavirus wasn’t made in a lab; genetic analysis shows it’s from nature” [2,3]. Actually the more we know, we get into more mystery. Genome analysis suggests that two coronaviruses (one from bat, another from pangolin) mighthave combined to form Covid-19, and thus, this might be a chimeric virus [4]. Whatever the etiology is, the fact is, covid-19 has become pandemic and deadly. We need to stop it through prevention and treatment.

How to prevent or stop transmission?

I was reading a paper last month “The Lessons of the pandemic”, which was published more than hundred years ago in 1919, in Science magazine [5]. That paper suggested “avoid needless crowding, smother your coughs and sneezes, wash your hands before eating”. Unfortunately after one hundred years, still we have to be taught and forced to do the same things.  Did we learn anything from history? May be not, unfortunately. We must have to learn and practice these hygiene to avoid Covid-19 spread. Also as this virus can be transmitted through air droplets, a protective mask is helpful. Also a new term ‘social distancing’ has been suggested to keep a distance of one meter between individuals. However, personally I feel the appropriate word should be ‘physical distancing’, not social distancing. As of today, there is no specific treatment for covid-19, and so testing and identifying virus carriers, isolating them and keeping a safe physical distance between individuals are most appropriate measures to control virus spread till now.

When we are talking about social distancing, we also need to think about social solidarity. Some days ago, I was reading an interesting article “Social distancing prevents infections, but it can have unintended consequences” [6], which I could relate with another article “We Need Social Solidarity, Not Just Social Distancing” [7]. It’s so important to keep a balance between distance and closeness. We need to fight against pandemic conditions with solidarity. Sometimes I am afraid, this distancing will make a severe impact on mental health and adverse effect on human relationships too. People from different professions should work in synchronization, in cooperation, with respecting each others. One important thing is after this pandemic, the world will not remain same, and there is a possibility of mass starvation and famine. People need to help poor and victims and work together to build a new world after this disaster.

Covid-19 pathophysiology

This Covid-19 spread so fast, and these viruses have very special feature on their spike, furin binding site, which can easily bind to host cell furin protein and easily enters into host cells [8]. Another important mechanism is, Human pathogenic coronaviruses (SARS-CoV, & SARS-CoV-2/ COVID-19) bind to their target cells through angiotensin-converting enzyme 2 (ACE2), which is expressed by epithelial cells of the lung, intestine, kidney, and blood vessels. The expression of ACE2 is substantially increased in patients with type 1 or type 2 diabetes, who are treated with ACE inhibitors and angiotensin II type-I receptor blockers (ARBs). Hypertension is also treated with ACE inhibitors and ARBs, which results in an upregulation of ACE2. ACE2 can also be increased by thiazolidinediones and ibuprofen. Experimental evidence suggest that ACE2 expression is increased in diabetes and treatment with ACE inhibitors and ARBs increases ACE2 expression. Consequently, the increased expression of ACE2 would facilitate infection with COVID-19. So, diabetes and hypertension treatment with ACE2-stimulating drugs increases the risk of developing severe and fatal COVID-19 [9].

Current progress in drug and vaccine

People all over the world are asking for drugs or vaccine. But it’s not an overnight process. It needs time. There is an interesting article by professor Shibo Jiang, “Don’t rush to deploy COVID-19 vaccines and drugs without sufficient safety guarantees” [10], which states that we must urgently develop measures to tackle the new coronavirus — but safety always comes first. Vaccine may come after one to two years if the trials are successful. The Japanese antiviral drug Flavirapir has showed success in treating mild cases, and many other antiviral drugs are on pipeline, but their clinical success is not yet confirmed [11]. An anti-malarial drug also showed some success and in some cases, approved under strict management, but misinterpretation about this drug made serious controversy after misuse in Nigeria [12]. An epidemiological study also proposed that BCG vaccination (from past) might have beneficial effect on covid-19 [13], but this is not proved experimentally and clinically. Personally I believe, this has very less chance to be effective. However, blood plasma from coronavirus survivors can be an effective short-term treatment for patients [14]. This old treatment strategy can give a new hope.

What lesson this virus outbreak gives us about nature?

As a nature lover and thinker of environmental biology, I am deeply concerned about the relationship between environmental damage and viral attacks. Bats are primary carrier of viruses, and environmental damages are one of the reasons for this. Read this interesting article “Bats are not to blame for coronavirus. Humans are” [15]. I was reading another interesting but alarming article by environmental editor of The Guradian [16] “Coronavirus: ‘Nature is sending us a message’, says UN environment chief”, where he says that destruction of wildlife and the climate crisis is hurting humanity, and covid-19 is only a sign of beginning of more damage. He also suggested, to prevent further outbreaks, the experts said, both global heating and the destruction of the natural world for farming, mining and housing have to end, as both drive wildlife into contact with people.

Let’s hope for an ending of covid-19 pandemic, let’s work together in solidary to eradicate the damage, let’s love and make our environment better for future.

References:

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Solid Waste Management in Dhaka City
– A Review on the Present Status and Possible Solutions 

A. H. M. Safayet Ullah Prodhan
Dept. of Biochemistry & Molecular Biology,
Jahangirnagar Univ., Savar, Dhaka-1342
Email : sapu.polock@gmail.com

Aflatun Kaeser
Dept. of Public Administration,
Jahangirnagar Univ., Savar, Dhaka-1342
Email : akzilany777@gmail.com

Abstract

Municipal Solid Waste Management (MSWM) is one of the main environmental problems in Dhaka, the capital city of Bangladesh. About 5000 tons of waste is being generated in Dhaka city every day among which only about more than half portion is properly collected and dumped. So, a huge amount of waste is being mistreated every day. In the present study an effort was made to represent the current waste management (WM) scenario of Dhaka city, how Dhaka City Corporation (DCC) is trying to cope with the WM problem, public concern about some WM practices, the problems created by improper WM system and some possible solutions to the WM problems.

Key words: Dhaka City Corporation; Solid waste; Recycling; Waste to energy.

1. Introduction

Dhaka is one of the most densely populated cities in the world having a population of about 20 million in an area of just 360 km². The total population is growing at a high rate of 1.4%; where as her urban population is growing at a faster rate of 3.4% per annum. The estimated population here by 2040 is 40 million. So, with the increasing rate of population, the rate of waste management problem of the city is also rising keeping a pace to it. In 1985 the total amount of solid waste in the city was 1040 tons/day, which rose to 3500tons/day in 1999 and might rise to 30000tons/day by the year 2020. Though a massive amount of municipal solid waste having 80% organic content and 50-70% moisture is generated every day, only about 50% of the waste is collected properly by DCC and dumped as landfill ^{[1] [2] [3]}. The improper management leaves behind a huge amount of uncollected waste, which has been creating environmental hazards in the city.

Dhaka City Corporations DCC, North, and South, have been trying to mitigate the problem taking new initiatives, but the problem seems to be aggravating more and more day by day. This huge waste seems to be beyond control of the DCC alone until the city dwellers come forward together to solve it.

The area required for land filling is increasing proportionally with the growth of waste. It is estimated that by 2020, the required area for landfill will be 206.31 acre to 309.46 acre with the collection efficiency of 50% to 75%.^[3] Though from the definition of waste we know that “Waste is an unwanted material that lacks financial value regardless of the time or season because there is no demand for such an item in the market”^[4]. But, this idea can be proved wrong by reusing and recycling the waste in a proper way. There are a number of recognized Waste-to-Energy (WtE) technologies in the world right now, which can turn the unwanted waste into energy. Moreover, the waste can be decomposed to create fertilizers. So, in lieu of being a burden, the waste of Dhaka city can become a blessing to the citizens if subjected to modern technology.

So, a comprehensive review on the scenario and problems of the waste management has been a demand of the time for a probable solution to the problem and at the same time turn this huge waste into resources. To perform the present work, we analyzed a number of research works, review articles, different online sources and reports of different government, non-government and international organizations on waste management on Dhaka city as well as other cities of the developed and developing countries. The aim of this review is to demonstrate the current waste management process in a proper way so that the existing problems related to it are minimized. At the same time, the work refers to possible ways and means to convert the municipal solid waste into resources. We strongly believe, if brought into practice, this could help the citizens of Dhaka and other cities to live a better life in an eco-friendly, congenial and sustainable environment, for present and future.

2. Existing Waste Management of Dhaka City Corporation

Primarily The DCC (Dhaka City Corporation) is liable for collecting and managing waste in Dhaka, Bangladesh. In spite of limited waste management service of Dhaka, door-to-door community based waste collection from households to local dust bins is considered as a success. Informal waste recycling systems are also highly fruitful in waste recycling and job creations for the poor.

Wastes are normally collected in a non-segregated manner and placed into little containers at households. Wastes are then collected by organizations delegated by DCC in vans to the secondary collection points. Waste trucks then carry the wastes to the landfill sites. A significant portion of the solid waste is operated by an informal market to be recycled. Scavengers (Tokais) collect the recyclable items from landfills and open dustbins and then sell those to a waste recycling dealer (Bhangari). Besides, the Hawkers buy recyclables from door to door and trade with the Bhangari. The items are then washed, dried and sorted by the recycling dealers and traded in the market.

Figure 1: Existing solid waste management system in DCC [5]

DCC does not have the capability to perform regulatory administration of these wastes. Besides, there are no laws to regulate the management of these wastes. So, these wastes are constantly being mixed with solid waste. ^[7]

DCC is divided into DCC (North) having 36 wards and DCC (South) Having 56 wards. In Dhaka, all the wastes are sent for landfilling in Matuail and Amin Bazar dumping ground. Wastes from 55 wards of Dhaka city are dumped in Matuail, and wastes from 36 wards are dumped in Amin Bazar. 852391 ton waste has been transported by DNCC to the landfill in 2016-2017 which is 24.77% higher than 2015-2016. The typical features of open dump sites in Dhaka city and waste collection trend (in tonnes) in DNCC since 2014-15 are presented below:

Table. 1: Typical features of Landfill sites in Dhaka City ^[8]

DCC (North) might have to manage over 5637728 ton waste in next 5 years. Growth percentage of waste collection in 2015-17 and projected waste volume in DNCC between 2017-18 and 2021-22 is appended in charts below:

Figure 2: Waste collection trend in tones in DNCC from 2014-15

Figure 3: Projected waste volume in DNCC during the period between 2017-18 and 2021-22 [7]

Figure 4: Waste collection growth percentage in DNCC [7]

Figure 5: Projection of future landfill requirement of Dhaka [9]

Landfill demand for disposal of MSW of Dhaka assessed by projecting population and waste generation for the period 2007-2025 is represented in the table below:

Table 2: Population, waste generation and waste volume in Dhaka city (2007 – 2025) ^[10]

3. Initiatives taken by DCC for Solid Waste Management

Around six thousands mini bins were installed at different points of Dhaka in earlier 2016. But the bins were installed not for houses or business entities, but for pedestrians so that they can put light garbage into those instead of hither and thither. But the pedestrians do not use the bins as was expected. They throw wastes on the street or footpaths. However, the street vendors prefer the bins. ^[11]

Figure 6: A man discarding an empty water bottle in a bin set up by DCC [12]

DoE has introduced a program by building two waste management plants, which will use solid waste collected from different parts of Dhaka to create compost fertilizer. One such plant will be in Matuail under Dhaka South City Corporation (DSCC) and the other in Amin Bazar under Dhaka North City Corporation (DNCC). Each of the plants will be capable of producing 20 tones compost fertilizer per day from solid waste. DCC expects producing fertilizer out of those plants by early 2018.^[13]

Figure 7.1: Before STS Construction

Figure 7.2: After STS Construction

Figure 7.3: Inside the STS

Construction STS in Dhaka has been a noticeable development in waste management. Construction of 52 STS in DNCC has enabled DNCC to remove great number of waste containers from the roads ^[7]. 45 STSs were planned to be built in DSCC by this time, but only 12 has been completed so far^[14]. DNCC plans to build 2-4 STSs in each of 36 wards. In areas of primary collection, the Primary Waste Collection Service Provider (PWCSP), an NGO is coordinating collections from households to STS. In 2016-17, 340 private operators were registered with the PWCSPECIES There are also unregistered operators, who collect wastes from households to STS. Containers on the street were bottlenecks in traffic movements, which were also solved by the construction of STS.

4. Public Concern about Waste Management in the City

Door-to-door service and waste dumping %: A study got some data showing that 88 % of upper group, 75 % of middle group and only 30 % of lower group received door-to-door collection service. 51 % of lower group households dumped their waste in vacant lands/river, while only 5% of upper group and 4% of middle group do that.

Figure 8: Door-to-door service and waste dumping % in Dhaka

Waste Segregation, Recycling & Composting: The same study shows that 70% of upper group, 68 % of middle group, and 75 % of lower group were not willing to participate in waste segregation activities. 88% of upper group, 95% of middle group and 100% of lower group were not willing to participate in recycling activities. 91% of upper group, 88% of middle group and only 29% of lower group give or sell recyclable waste. 80% of upper group, 83% of middle group and 96% of lower group were not participating in any community activities. 85% of upper group, 96% of middle group and 98% of lower group were not willing to participate in composting activities. 77% of all respondents replied that they were willing to participate in activities on solid waste management in their communities.^[15]

Figure 9: Waste segregation, recycling, composting and community activity status of diff. group of people in Dhaka

Another study expresses that, people ranked natural environment as 6 among 8 sectors suggested for government funding and solid waste dumping as 3 among 8 environmental problems. On average the respondents in Dhaka were willing to pay only 13 TK (0.18 USD) waste collection service charge per month. ^[16]

5. Physical Composition of DCC Solid Waste

Cultural tradition, food habitat socio-economic and climate conditions affect the composition of MSW. Typical characterization of MSW in Dhaka is reflected below:

Figure 10: Typical characterization of MSW in Dhaka [9]

6. Present status of Solid Waste in Dhaka City

The Dhaka City Cooperation estimated that, of the total daily generation of 3500 tons of solid waste (The value is found higher in some recent studies), among them 400 tons go to road side and open space.^[6]That means about 11.5% waste remains untreated and these wastes pollute environment. The DCC clearly states that, its collection system cannot cope with the task of handling the large volumes of refuse produced by the ever-growing numbers of city dwellers, and that only 40-50% of the solid waste produced is being collected. 50% of the daily generated waste remains uncollected in the city and disposed at official dump sites. Only 14-17% of the total municipal budget is used for solid waste management which is approximately 0.5 USD per capita per year. As a result, the uncollected waste is primarily dumped illegally in the neighborhood’s streets, wastewater drains, ponds, lakes etc. or managed informally. Uncollected waste has been recognized as the root of inferior environment such as scattered garbage, offensive odor, drain clogging, water pollution and mosquitoes.^[6]

7. Probable solutions to present problem of Solid Waste Management in Dhaka City

To solve the existing problems regarding waste management in Dhaka city, we have to focus on three sectors:

• Smart dumping and transportation of waste
• Energy generation from waste
• Fertilizer generation from waste

7.1. Smart Dumping and Transportation of Waste

In existing waste management system, the dustbins are located on street and therefore when wastes are overflowed they fall on the street and thus cause environmental pollution. Besides, the dustbins cover a large area of street and hamper traffic movement resulting in traffic jam. Underground dust containers can be the best solution to such problems.

In this system, (like in India) the dustbin is kept underground in the form of a large bin, with a relatively narrow opening through which the wastes are deployed inside. By this process the waste is kept underground and thus there is almost no risk of pollution and street clogging. The process is shown below in systematic order:

Figure 11.1 – A personnel is deploying waste in the underground bin

Figure 11.2 – The waste is deployed from a Van

Figure 11.3 – Collection of waste from the Underground bin

Figure 11.4- Reinserting the bin in the Underground chamber

7.2. Energy Generation from the Waste

Waste to energy (WtE) option means waste treatment process generating energy in the form of electricity, heat, or transport fuels. WtE is considered as one of the eight technologies having significant potential to contribute to future low-Carbon energy system by the world economic forum report “Green Investing: Towards a Clean Energy Infrastructure” published in 2009.^[8] It is interesting to note that the electrical energy generation potential increases from 456,900 MWh in 1995 to 1,894,400 MWh in 2025, and the electrical energy recovery from urban solid waste generation of Dhaka city can supply a significant portion of the consumption requirement of electrical energy of the city.^[18] Various technologies can be utilized for energy conversion from waste. Each of these WtE solutions has specific features, and can be more or less feasible depending on many parameters. The following list gives an overall picture of the available options of WtE technologies:

Figure 12: Current waste to energy technologies [19]

7.2.1.1. Incineration

The complete oxidation of the combustible materials present in the solid waste is referred to as incineration of MSW. Initially, the moisture contained in the solid waste is evaporated and volatilized by the heat in the combustion chamber. The actual combustion process is then begun by the ignition of resulting gases in the presence of combustion air which converts waste fuel into heat, flue gas, and ash. A high-pressure superheated steam is produced from water by the heat, which is then sent either to the steam turbine to produce electricity which is incorporated with generator, or used to supply process steam.

Figure 13: Model of an incinerator [20]

C + O₂ CO₂; oxidation of Carbon

½ O₂ + H₂ H₂O; oxidation of hydrogen

N + O₂ NO₂ (NO_X); oxidation of Nitrogen

S + O₂ SO₂ (SO_X); oxidation of sulfur ^[21]

Some of the generated gases are toxic. So, they should be removed before emission. SCR system is used for the reduction of NO_X as well as PCDD/F. The main reactions involved are:

C₁₂H_nC_l8 nO₂ + (9 + 0.5 n) O₂→ 12CO₂ + (n-4)H₂O + (8-n)HCl
and
C₁₂H_nC_l8 nO + (9.5 + 0.5 n) O₂→ 12CO₂ + (n-4)H₂O + (8-n)HCl

Volatile inorganic compounds and heavy metals are totally or partly evaporated. These substances are transferred from the input waste to the flue-gas and the fly ash it contains. A mineral residue fly ash (dust) and heavier solid ash (bottom ash) are created. ^[22] They affect the energy balance through its mean heat capacity, even though does not particularly participate in the combustion process. Ferrous and non-ferrous metals can be recaptured and the remaining ash can be enhanced to be used for building and road construction.^[19]

A study shows that incineration of MSW from Chinese cities present some unique challenges because of its low caloric value (3000-6700 kJ/kg and high water percentage (~50%). So, MSW has to be co-fired with coal in a CFB incinerator. ^[23]

7.2.1.2. Thermal Gasification

Gasification plant thermally treats fuels without allowing enough oxygen for complete combustion. It is typically smaller and more flexible than combustion plants and typically consumes 25 to 350 thousand tonnes of waste per year. ^[25]Either the heat required for this process is provided by partial combustion to gasify the rest or heat energy is provided by using an external heat supply. The solid waste is broken down into useful byproducts that contain a mixture of hydrogen, Carbon Di-oxide  and Carbon monoxide. The produced syngas can be used for various applications after syngas cleaning process. After cleaning,high quality fuels, synthetic natural gas (SNG) and chemicals can be produced by it. Syngas can be used in a more efficient gas turbines and/or internal combustion engines or it can be burned in a conventional burner that is connected to a boiler and steamturbine. ^[19]  Some of the chemical reactions involved in thermal gasification are given below

CH₄ + H₂O → CO + 3H₂O (CH₄ decomposition – endothermic)

CO + H₂O→CO₂ + H₂ (Water gas shift reaction – exothermic)

C + H₂O → CO + H₂ (Heterogeneous water gas shift reaction – endothermic)

C + CO₂→ 2CO (Boudouard equilibrium – endothermic)

The overall equation of global gasification reaction is written as follows; waste material is described by its ultimate analysis (CH_xO_y):

CH_xO_y +wH₂O +mO₂ +3.76mN₂→ aH₂ +bCO +cCO₂ +dH₂O +eCH₄ +fN₂ +gC

Here w is the amount of water per mole of waste material, m is the amount of O₂ per mole of waste, a, b, c, d, e, f and g are the coefficients of the gaseous products and soot (all stoichiometric coefficients in moles). ^[26]

Figure 14: Schematic of overall process for 100 TPD thermal plasma Gasification plant [26]

During Pyrolysis organic waste is heated in the absence of air in between 500-800°C to produce a mixture of gaseous (Syngas) and/or liquid fuels (Tar) and a solid (Char), inert residue (mainly Carbon).^[28] The pyrolysis temperature and the rate of heating determines the quantity of H_2, CO, CH₄ and other hydroCarbons and their proportion.^[19] The lower temperature pyrolysis processes are used for maximizing the production of bio-oil which is a potential precursor to the production of many other chemicals in a bio-refinery context. The higher temperature pyrolysis processes have been developed in order to maximize the production of syngas, which is more easily converted to electricity. ^[28]

Reactions involved in pyrolysis of MSW:

Primary reaction:

The primary decomposition reaction of the solid waste sample can be represented by equation 1. The decomposition is a single reaction with no competitive selectivity towards any of the products formed. Where, k is the reaction rate constant for decomposition of waste sample to form char (Sp), tar (Tp) and gaseous (Gp) products. a, b and c are the yield coefficients (kg of product formed/kg of reacted biomass).

Sample  → ^kaG_p + bT_p + cS_p … … … (1)

Secondary reaction:

The tar obtained from primary decomposition reactions cracks during the secondary decomposition reaction. Equation 2 correlated the thermal decomposition of tar.

bT_p  → ^kseG_s +  fS_s  … … … (2)

Here G_s is the representation of total gases and S_s is the total char and refractory tar produced during tar (produced from primary decomposition) decomposition. e and f are the corresponding yield coefficients (referring to the initial biomass since the coefficient b has been considered in the equation; and k_s is the reaction rate constant. However, poly-ethylene (PE) cracking takes place through two parallel reactions as seen in Equation 3.

BT_p  →  ^ks1 G _s ,

BT_p  →  ^ks2 S _s … … … (3)

Here, B is the coefficient of tar containing PE; and k _s1 and k _s2 are the reaction rate constant for the two parallel decomposition reaction to form gaseous and solid (char and refractory tar) product respectively. ^[28]

Figure 15: Fluidized bed pyrolysis reactor [31]

7.2.2.1. Fermentation

Fermantation is a process by which organic waste is converted into an acid or alcohol (e.g. lactic acid, ethanol) or hydrogen in the absence of oxygen by microorganisms (e.g. yeast, bacteria) leaving a nutrient-rich residue. There can be dark fermentation or photo fermentation. Fermentation leads to ethanol, biodiesel, and hydrogen which are good sources of energy. Methane can be produced from these substances by methanogenesis. ^{[19] [20] [32]}

Figure 16: Scheme of anaerobic metabolism pathways [32]

Production: An optimal sized bio-ethanol fermentation plant produces about 200,000-300,000 tons of ethanol per year.^[19]

7.2.2.2. Anaerobic Digestion

Micro-organisms in controlled conditions convert biomass into biogas comprising primarily of methane and Carbon Di-oxide , and a stabilized residue known as digestate, a source of nutrients used as fertilizer. This process is called anaerobic digestion.^[34]As MSW is normally rich in carbohydrates, proteins, and minerals, it has been widely used as raw material for anaerobic digestion.^[33] The overall conversion method can be described as a three-stage procedure which may occur simultaneously in an anaerobic digester. These stages are: (i) hydrolysis of insoluble biodegradable organic substance; (ii) generation of acid from small soluble organic molecules; and (iii) methane synthesis. The three-stage scheme involving various microbial Species can be presented as follows: (1) hydrolysis and liquefaction; (2) acidogenesis and (3) methane fermentation.^[32] The time of operation per cycle, meaning how long it takes for the organic waste to be processed by an AD plant, is usually 15 to 30 days.^[19]Efficiency of an AD process depends on the type of waste used as feedstock and the vessel used to host the procedure. ^[35]

The synthesis of methane, which is the final product of anaerobic digestion, happens by two major ways. Acetic acid, hydrogen, formic acid, and methanol can be used as energy sources by the various methanogens. The overall reaction is:

CH₃COOH → CH₄ + CO₂

Bacteria that utilize acetic acid are from acetoclastic group which comprises two main genera: Methanosarcinaand Methanothrix. Some methanogens use hydrogen to reduce Carbon Di-oxide  to methane (hydrogenophilic methanogens) according to the following overall reaction:

4H₂+ CO₂ → CH₂ + 2H₂O^[32]

Biogas can be used to generate electricity, process steam, or in the transportation sector as fuels and consists of 60%-70% methane (CH₄), 30%-40% Carbon Di-oxide (CO₂). ^[35]The bio-fertilizer is generated which is pasteurized to make it pathogen free and can be applied twice a year on farmland. The technology is widely used to treat wastewater and can also be effectively employed to treat organic wastes from domestic and commercial food waste, to manures and biofuel crops.^[19]

7.2.2.3. Landfill Gas Capture

Landfills are a significant source of greenhouse gas emissions, and methane in particular can be captured and utilized as an energy source. Organic materials that decompose in landfills produce a gas comprised of roughly 50% methane and 50% Carbon Di-oxide , called landfill gas (LFG). Methane is a potent greenhouse gas with a global warming potential that is 25 times greater than CO₂. Capturing methane emissions from landfills is not only beneficial for the environment as it helps mitigate climate change, but also for the energy sector and the community.

Applications for LFG include direct use in boilers, thermal uses in kilns (cement, pottery, bricks), sludge dryers, infrared heaters, blacksmithing forges, leachate evaporation and electricity generation to name a few. LFG is increasingly being used for heating of processes that create fuels such as biodiesel or ethanol, or directly applied as feedstock for alternative fuels such as compressed natural gas, liquefied natural gas or methanol. The projects that use cogeneration (CHP) to generate electricity and capture the thermal energy are more efficient and more attractive in this sense.

The process of capturing LFG involves partially covering the landfill and inserting collection systems with either vertical or horizontal trenches. Both systems of gas collection are effective, and the choice of design will depend on the site-specific conditions and the timing of installation. They can also be employed in combination and an example is the utilization of a vertical well and a horizontal collector. As gas travels through the collection system, the condensate (water) formed needs to be accumulated and treated. The gas will be pulled from the collection wells into the collection header and sent to downstream treatment with the aid of a blower. Depending on the gas flow rate and distance to downstream processes, the blowers will vary in number, size, or type. The excess gas will be flared in open or enclosed conditions to control LFG emissions during start up or downtime of the energy recovery system, or to control the excess gas, when the capacity for energy conversion is surpassed.

Figure 17: Landfill gas system[38]

7.2.3. Chemical Conversion

7.2.3.1. Esterification

The Esterification process involves the reaction of a triglyceride (fat/oil) with alcohol in the presence of an alkaline catalyst such as sodium hydroxide. A triglyceride has a glycerin molecule as its base with three long fatty acids attached. The alcohol reacts with the fatty acids to form a mono-alkyl ester, or biodiesel, and crude glycerol, used in the cosmetic, pharmaceutical, food and painting industries. The alcohol used is usually either methanol, which produces methyl esters, or ethanol, with ethyl esters. The base applied for methyl ester is potassium or sodium hydroxide, but for ethyl ester the former base is more suitable.

Figure 19: Base Catalyzed Transesterification reaction [40]

Figure 18: Biodiesel production process [39]

Waste Concern says, if recyclable materials including organic waste for composting is seperated, the total waste can be reduced upto 60-70%. Only 15% of total waste which are recyclabe items is being collected by 87000 waste pickers leaving behind a large amount organic waste from which a huge amount of organic fertilizer can be generated. They conducted a survey in Dhaka and surrounding areas which says that 94% of the farmers are willing to buy compost but the yeild is so little that the organic matter in soil was found less than 1% against the critical level of 3%. ^[40]

Figure 20: Fertilizer generation process from waste

Fertilizer can be produced by biologial treatment of waste like anaerobic digestion and composting. Anaerobic digestion is discussed earlier. Various types of composting methods can be used to generate organic manure from municipal solid waste. Static pile and contained pile composting, vermi composting, bin composting, windrow composting, rotatory drum composting, tunnel composting and in-vessel composting are some of the common composting procedures. An overview of the composting procedures is represented in the table below:

8. Concluding Remarks

Though a number of possible ways are discussed to eradicate the waste management problem from Dhaka city and turn the waste into resources, we couldn’t discriminate between the waste-to-energy techniques. Each of the waste-to-energy process has great potential to convert the hidden power of municipal solid waste into resources because of greater organic portion in the waste of Dhaka. But as there are financial boundaries for the govt. of a developing country like Bangladesh, it’s better implementing the biochemical and chemical procedures initially as well as steps to generate fertilizers by composting as these processes are cost-effective. The practice of proper, scientific, and hygienic management of waste and at the same time turning it into energy or resource, could ensure a safer life of people and at the same time ensure a sustainable healthy atmosphere for our future generations. There is a huge gap between the researchers, policy makers and the public, who are the main executives of the target. So, the research findings should not be poorly considered in policy making like that is going on now. At the same time, researches should be public benefit oriented as well as the research paper’s language should be up to an understandable level of the policy makers, stake holders and the public. The policy makers should build a bridge between the researcher and the public by formulating   sustainable and practicable policies. Only this trio joint-venture can solve the monumental waste management problem in our country and likewise all over the globe. At the same time the Government and the public should come forward with enthusiasm to time to time to support and modify the policy to make it more time worthy and eco-friendly.

9. Limitations

Though our target was to publish a complete article with the most recent information about the solid waste management of different developed cities in the world, but due to certain limitations and insufficiency of time, it could not be fully possible. So, we had to depend on some earlier publications in cases. Moreover, latest data of different topics and places on waste management are lacking. We also observed major deviations of the same value in different articles in some cases and could not have enough time to confirm with those publications. But, our next target is to prepare a complete scientific paper with latest substantial data with reference about all aspects of Solid Waste Management of the city and the recommendations for the way out of such environmental problems.

10. Acknowledgement

Authors are grateful to Nature Study Society of Bangladesh (NSSB) for the active cooperation and support rendered for the review work.

11. Abbreviation

AD – Anaerobic digestion

CFB – Circulating Fluidized Bed

CHP – Combined Heat and Power

DCC – Dhaka City Corporation

DNCC – Dhaka North City Corporation

DoE – Department of Environment

DSCC – Dhaka South City Corporation

JICA – Japan International Cooperation Agency

LFG – Landfill Gas

MSW – Municipal Solid Waste

MSWM – Municipal Solid Waste Management

MW – Mega Watt

MWh – Mega Watt Hour

NGO – Non-government Organization

PCBs – Polychlorinated Biphenyls

PCDD/F – Polychlorobenzodioxins / polychlorodibenzofurans

PWCSP – Primary Waste Collection Service Provider

SCR – Selective Catalytic Reduction

SNG – Synthetic Natural Gas

STS – Secondary Transfer Station

USD – United States Dollar

VOCs – Volatile Organic Compounds

WM – Waste Management

WtE – Waste to Energy

[N.B.-This article was earlier published in the Journal Book – Environmental Thoughts, Part-1, 2019;  (ISBN: 978-984-93766-2-0)]

Referrences:

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সর্পিল আকার ধারন করা লিয়ানা

আজ আমার সিরুর কথা খুব মনে পড়ছে। আমাদের বাড়িতে বেশ বড় সুপারি বাগান ছিলো প্রতি বছর নভেম্বর ডিসেম্বর মাসে পাকা সুপারি বাজারে বিক্রি করার হিড়িক পড়ে যেতো এমন সময় সিরু এসে হাজির হতো। সে বিশাল বাগানের একপাশের একটি গাছে উঠে আর নামতো না,একটু শরীর ঝুলিয়ে এক গাছ থেকে অন্য গাছে চলে যেতো এভাবেই বানরের মত এই গাছ থেকে ওই গাছে নিজেকে ট্রান্সফার করে তখন আমাদের অনেক আনন্দ দিয়েছে। ছেলেবেলায় সিরু ছিলো আমাদের কাছে হিরু, কত কল্পনা ছিলো ইচ্ছে ছিলো আমিও বড় হয়ে সিরুর মত এক গাছ থেকে অন্য গাছে যাবো, বাচ্চাদের অনেক আনন্দ দিবো! সিরু হয়ে উঠাই ছিলো আমার প্রতিজ্ঞা ও প্রথম পছন্দ। যাই হোক আমার সিরুর মত হয়ে উঠা হলো না সুপারি গাছের একহাত উপরেও কখনো উঠতে পারিনি।

কিছুদিন আগে বোটানিক্যাল গার্ডেনে ঘুরতে গিয়েছিলাম সেখানে অনেক পুরানো কিছু গাছের মধ্যে প্রাকৃতিক ভাবে লিয়ানা এক গাছকে আরেক গাছের সাথে বনে বসবাস কারি প্রানীদের চলাচলের জন্য সংযোগ স্থাপন করে দিয়েছে যাকে দেখলে মনে হয় প্রাকৃতিক সেতু। আসলে লিয়ানা হলো এক প্রকার কাষ্ঠল লতা যা অনেক মোটা হয় ও অন্য গাছের উপর বেয়ে উঠে নিজেদের বংশ বিস্তার করে। তবে লিয়ানা শ্রেণীবিন্যাসকৃত কোন নির্দিষ্ট উদ্ভিদের গন,পরিবার বা প্রজাতি নয় অর্থাৎ একাধিক পরিবারের ভিন্ন ভিন্ন প্রজাতিকে একত্রে আমরা লিয়ানা বলতে পারি।

লিয়ানার উপর দিয়ে বানর হেটে যাচ্ছে

গহীন অরন্যে এইসব লিয়ানা বনের ইকোসিস্টেম ও ফুড চেইনে অত্যন্ত গুরুত্বপূর্ণ ভুমিকা পালন করে যেমন কিছু মাংশভোজী প্রানীরা অন্য প্রানীদের উপর নির্ভরশীল এমতাবস্থায় এই সব লিয়ানাকে নির্ভর করে শিকার ধরে অথচ লিয়ানা না থাকলে কখনোই শিকার ধরতে পারতো না। এছাড়া যে সকল মানুষ বনের উপর সরাসরি নির্ভর করে জীবিকা নির্বাহ করে তারা গহীন বনের মধ্যে নদী পাহাড় পাড়ি দেয়ার জন্য লিয়ানাকে ব্যবহার করে জীবন্ত সেতু তৈরি করে একস্থান থেকে অন্য স্থানে যাতায়াত করতে সক্ষম হয়।

লিয়ানার তৈরি জাল

গহীন অরন্যে লিয়ানা ও অন্য উদ্ভিদের মধ্যে প্রতিযোগীতা শুরু হয়। স্বাভাবিক ভাবে লিয়ানা পরাশ্রয়ী ও আরোহী কাষ্ঠল লতা তাই এদের প্রধান ও একমাত্র ভরসা হলো অন্য বৃক্ষ, কিন্তু বৃক্ষ এদের এড়িয়ে চলার চেস্টা করে। বিজ্ঞানীরা অনেক বছর যাবৎ পর্যবেক্ষণ করে দেখেছেন লিয়ানার অত্যাচারে অনেক উদ্ভিদ বাঁকা হয়ে উপরের দিকে বৃদ্ধি পায় আবার নাছোড়বান্দা লিয়ানা কখনই আশ্রয়দাতা উদ্ভিদকে ছাড়তে চায় না। এই প্রতিযোগীতার মধ্যে যে যাকে পরাজিত করতে পারে তারই জয় হয়। তবে কিছু কিছু উদ্ভিদ লিয়ানার শিশু অবস্থা টের পেয়ে এলিলো কেমিক্যাল নিঃসরণ করে ফলে শুরুতেই এদের বিস্তার রোধ হয়ে যায়। এখানেও প্রকৃতি বিজ্ঞানি চার্লস ডারউইনের বিখ্যাত উক্তিটি প্রযোজ্য “সারভাইবাল অব দ্য ফিটেস্ট”।

বেত জাতীয় লিয়ানা

বনজীবি মানুষ গুলো তাদের খাদ্য বস্ত্র ও বাসস্থানের জন্য সরাসরি লিয়ানার উপর নির্ভরশীল। কারন কিছু বেত জাতীয় লিয়ানা পাওয়া যায় যা দিয়ে মূল্যবান আসবাবপত্র তৈরি করা হয় তারা এই সব লিয়ানা সংগ্রহ করে চড়া দামে বিক্রি করে জীবিকা নির্বাহ করে। এছাড়া বাসস্থান তৈরির কাঁচামাল হিসেবে এইসব লিয়ানা ব্যবহার করে। লিয়ানা গুলো চমৎকার ভাবে বাঁকানো শেপ নিয়ে বৃদ্ধি পেতে থাকে পরিপক্ক অবস্থায় এইসব লিয়ানা বিভিন্ন প্রকার শোপিস, আসবাবপত্রের ডিজাইনের জন্য ব্যবহার কল্পে মূল্যবান সামগ্রী হিসেবে বিক্রয় করা হয়।

লিয়ানার তৈরি জীবন্ত সেতু

এছাড়া বিভিন্ন প্রকার মেডিক্যাল ইন্সট্রুমেন্ট, মিউজিক্যাল ইন্সট্রুমেন্ট তৈরিতে বিশেষ কিছু লিয়ানা ব্যবহার করা হয় যা অত্যান্ত উঁচু মূল্যে বিক্রয় করা হয়। আজকাল বিজ্ঞানিরা মানবদেহে ভাঙ্গা হাড়ের বিকল্প হিসেবে লিয়ানা ব্যবহারের চেষ্টা করছে, তবে এই বিষয়টি এখনো গবেষনার পর্যায়ে আছে, হয়ত একদিন এমন সুসংবাদ আমরা পেয়ে যাবো যে, লিয়ানাকে মানুষের হাড়ের বিকল্প হিসেবে ব্যবহার করতে কোন বাধা নেই।

দ্বিখন্ডিত আকারের লিয়ানা

আশ্চর্য ব্যাপার হলো গহীন অরণ্যে এইসব লিয়ানা গুলো প্রায় ৫০০ থেকে ৪০০০ ফিট পর্যন্ত লম্বা হতে পারে ও ৫০-৬০ বছর ধরে এরা নিরবিচ্ছিন্ন ভাবে বনে বসবাসরত প্রানীকুলের জন্য অক্সিজেন(O2) সরবরাহ করে থাকে। এছাড়া বিশাল বন তার বক্ষে ধারন করে থাকে বিশাল এক প্রাণীকুলের সুতরাং এদের জন্য দৈনন্দিন প্রচুর খাদ্যের প্রয়োজন হয়। একটি সমীক্ষায় দেখা গেছে এই লিয়ানা বনে বসবাসকারী প্রাণীকুলের মোট খাদ্য চাহিদার ৬০% যোগান দিয়ে থাকে। একটা ব্যাপার খুবই পরিস্কার যদি লিয়ানার বংশবৃদ্ধি কমে যায় তাহলে খাদ্য ঘাটতিতে অনেক প্রয়োজনীয় প্রাণী নিশ্চিহ্ন হয়ে যাবে। এককথায় বলা চলে গহীন অরণ্যের ইকোসিস্টেম তথা পরিবেশের জন্য লিয়ানা খুবই অগুরুত্বপূর্ণ ভূমিকা পালন করছে।

সিরু হলো একজন মানুষের নাম, তার ভাল নাম ছিল সিরাজ, এলাকার লোকজন তার নাম সংক্ষিপ্ত করে সিরু বলে ডাকতো। বর্তমানে সে বেঁচে নেই।

ছবিঃ গুগলের সৌজন্যে।

The post গহীন অরণ্যে জীবন্ত সেতু লিয়ানা appeared first on NSSB.

River and River Basin Diversity of Deltic Bangladesh
– A Review on the Country’s Rivers and River Basins

Niamul Naser, Ph.D

Professor of Zoology
Faculty of Biological Sciences
University of Dhaka, Dhaka
Email: mnnaser@du.ac.Bangladesh

Introduction

Rivers are the key point of natural resources, integrated with the culture and civilization of related people. Early civilizations like in ancient Egypt (River Nile), Mesopotamia (River Tigris–Euphrates), ancient China (River Yellow and Yangtze) and Indus valley (River Indus) still bears the sign of social system – a history of mankind.  In Indian sub-continent, the Indus valley civilizations namely Harappa and Mohenjo-Daro are noted for their ancient cultural ramifications and urban designs.  These cultures were ruined due to the change in courses of mighty river Indus. It has been stated by some historians that, communities of these civilizations migrated from the Hindu Kush mountain valley to the other side of Himalayas, crossing the Thor desert, to settle in the source valley of river Ganges. In Bangladesh all major cities and cultural hubs are situated by the major rivers.   Cultural city like ancient Rajshahi, Khulna, Barishal , and Dhaka are situated beside the Padma, Rupsha, Kitonkhola and Buriganga rivers respectively. There were regular steamer services from most of these cities to Kolkata in British-Indian regime.  Thus the higher educated society and intellectuals were the domiciles of these cities.  It has been noted that the renowned Noble laureate Poet Rabindranath Tagore wrote the best songs and poems in his life, while enjoying the natural beauty in moon-lit nights in rivers on his Bazra (large boat), whenever he came to see his Jaminder (landlord) assets in Jashore (the then Jashore of the Bengal).

Bangladesh, a riverine country is famous for its rivers and their geographical positions. According to the Bangladesh Water Development Board (BWDB 2011) 57 are trans-boundary in nature of 407 rivers. Most of the rivers flow from north to south and finally discharging the water into the Bay of Bengal. Three of Asia’s most mighty rivers, the Ganges-Padma, the Brahmaputra-Jamuna and the Meghna flow through Bangladesh. The country’s major rivers have originated mainly from outside of the country. These rivers carry 1.2 trillion cubic meter of water along with more than 1 billion tons of sediment every year from the catchment area outside the country (BWDB 2011). This sediment is carried out by numerous tributaries and distributaries throughout the country, making them more dynamic especially in the rainy season. As a result, due to their drainage capacity the rivers frequently change their courses, creating sedimentation loaded sand bars (chars), some of which even rise up during the dry seasons.

For many reasons water is one of the main resources of Bengal delta. The land, crops, fisheries, economic growth, and development of the country is highly influenced by the rivers. River of Bangladesh carries the major fresh water resources providing support to diverse aspects of the country, like agriculture, fisheries, and navigations.  From the time immemorial the river-fish and other aquatic animals play an important role in the biodiversity and nutritional resource of protein food for human and animals alike. About 80% percent of the dietary protein in the country comes from fish and fish products. Moreover, during monsoon, due to rain and trans-boundary inflow of water, cause the country’s major rivers, their tributaries and distributaries to overflow, resulting in inundation and water logging, which turns into devastating flood in some years, causing enormous loss of life and property that hinders development. But on the other hand, a fresh deposit of rich silt replenishes the used soil fertility in those flood-affected areas. Rivers also drain excess of water into the Bay of Bengal that comes from monsoon rainfall. Thus, the river system of Bangladesh is a valuable resource of the country, though it causes considerable loss in time to time.

Naming of Rivers

Rivers of Bangladesh are named in many fascinating ways, depending upon their locations and pathways. Usually rivers of Bangladesh are considered feminine in gender as they produce natural resources. However, few rivers are regarded as male, like the Brahmaputra, Kapathakhya, etc. Some story can create a unique name for a river like, the Karnophuli. It was said that a tribal girl lost her flower, she used as her earring in the river, so it is named in this way; Karno (=ear) and phuli (=flower).  In many instances, same rivers are also named after their change of courses. Like the Ganges originated in the Himalayas, but as it entered the Bangladesh territory, it was named as the Padma.  The river Brahmaputra after entering into Bangladesh has changed its name as the Jamuna and after it joined the river Padma, it is called the Meghna.  The famous river Gorai (89 km) in its course, before falling into the Bay of Bengal is named differently, as Modhumati river (137 km) as it crosses Magura district, and Baleswar river (146 km) as it passes through Sundarbans.

Special Rivers and their Segments

Trans-boundary Rivers

A trans-boundary river is a river that crosses at least one political border, either a border within a nation or an international boundary (Banglapedia, 2012). In Bangladesh, when a river crosses an international boundary or in other words, when a river is shared by more than one country, is called a trans-boundary river. There are 57 such trans-boundary rivers in Bangladesh. Among these, 54 rivers enter here from India and the rest 3 from Myanmar. The rivers like Ganges, Brahmaputra, and Barak are the major trans-boundary rivers, which bring more than 90 % percent of water from the upper riparian areas.  In notable areas like the Padma in Rajshahi and the Modhumati in Satkhira, demarcate the political boundary between Bangladesh and India. Likewise, the river Naaf in Cox’s bazar demarcates the border between Bangladesh and Myanmar.  The trans-boundary rivers play an important role in the political relationships among the riparian countries, particularly between India and Bangladesh. The list of trans-boundary rivers are given in the river list tables with asterisk ‘*’marks.

Tributaries

Tributaries are small rivers, which originate from different sources and fall into a river.  For instance, river Tista is the tributary of river Jamuna, while river Surma and Kusiara are tributaries of river Meghna.

Distributaries or branches

When a river in its course is diverted out into a smaller river is known as a distributary or branch.  These branches may lead towards the sea alone, or joining another river or gain with the same river in its course. For instance, Ichamoti, Gorai, Arial Khan are the distributaries or branches of river Padma.

Confluence

When different rivers unite they form a confluence.  River Padma and Jamuna unite to create a confluence near Goalundo Ghat. But, before meeting together they also formed the river Meghna near Chandpur.

Estuarine and coastal rivers

Estuary is a place where rivers meet the sea, and the river-led freshwater mixes with marine water. The Meghna river estuary is the largest in the country; besides, estuaries of Nijhum Dweep, Naaf River, and Sundarban, are also notable in the coastal region of Bangladesh.

Some Selected Rivers of Bangladesh

River Padma is a trans-boundary river with our neighboring country India.  It originates from a sub-glacial melt-water cave at the base of Himalayan glacier (Gadgetry) known as Gurumukhi, about 21 km south-east to the Gadgetry. From the Hindukosh ice-burg of the Himalayan Mountain, India, it flows as the Hindu religion’s sacred river Ganges or Ganga (in Hindi). In its course as it joins the river Yamuna in Allahabad, river Gomti in Varanasi, rivers Ghaghara and Gandak in Patna and river Kosi in Kurshila of India, the Ganges enters into the Bangladesh territory as the river Padma through the Godagari upazilla of Chapai Nowabgonj district. The Padma is famous for its famous epic “Padma Nodir Majhii” (The boatman of Padma River), was written by eminent writer Manik Bondopadhay long ago in 1862, focusing on the living standard and hardship of a boatman’s life. The river is also famous, home and abroad, for its tasty Hilsa fish. However, this national fish of Bangladesh is no longer available in the upstream Padma as it was profound earlier. This is due to the siltation barrier in Hilsa migration route due to low water flow, caused by the Farakka barrage, India.

River Halda raises from the Badnatali hill ranges in Chattogram Hill Tracts and enters into Chattogram district through Fatikchhari upazilla. From there it flows to south-west and falls into the river Karnafuli at Kalurghat. Its total length is about 81 km, of which 29 km. up to Nazirhat is navigable by big boats throughout the year, while the next 16 to 24 km to Narayanhat is navigable by small country boats. The Halda river also has several hill streams flowing down into it from the Chattogram Hill Tracts to its east, watering and irrigating the entire Halda basin up to Kalurghat before falls into the Karnafuli river. This river is very important as its morphological and hydrological nature has embraced it as to be the one and only natural carp spawning ground in Bangladesh.

River Kobadak is famous for the poem written on it by eminent poet Michael Madhusudan Dutta (1824-1873), who was born in Jashore district, in Sagardari village under Keshabpur Upazilla, which stands by this river.  Once the river-water was as clear as the eye of a bird, and thus named thus as ‘Kapotaksha‘ (Kapotaksa), which means the ‘pigeon-eyed’ in Sanskrit.  At present, the river flows as an offshoot branches from river Bhairab, flowing south to meet river Shibsa, next to Kopilmoni at Paikgachha UZ., in Khulna district. The river has lost its navigability in many places and at present, receives only the local rainwater during the monsoon (Banglapedia, 2012).

River Kocha is the only known natural ground for Golda prawn (Macrobrachium rosenbergii) broods, the silver treasure of Bangladesh.  Kocha river is a large river that exists in the southern part of our country. It forms by the union of two mighty rivers Modhumoti and Shondha near Hularhat. By merging two rivers it got a new name Kocha river, which continues its course to the Bay of Bengal (Banglapedia, 2012).

Poshur river was the cultural route of the then Bengal under British-India.  The steam-engine shipping line followed the Kolkata to Khulna route through this river in the Sundarbans. Situated at the south-western part of Bangladesh and a distributary of the Padma, this river continues as Rupsa river in Khulna district. It has been named differently at different parts. Like, it is called Shibsa River within the Sundarbans, and again Kunga River as it flows towards the sea. It is the deepest river in Bangladesh (Banglapedia, 2012) and all its distributaries are tidal in nature.

Gorai-Madhumati river is one of the longest rivers in Bangladesh and a distributary of the river Padma.   The upper reach is called the Gorai, and the name changes to Modhumoti in the middle and Baleswer at the end near Sundarbans reserve forest.  The river runs through Kustia, Jashore, Faridpur, Khulna and Barguna districts of Bangladesh.  Noble laureate poet Rabindranath Tagore used to live for some time at Shilaidaha by the river Padma, close to Gorai River at Kustia, as his grandparents were from that area.  He named the river as Gouri for some memorial cause.  Famous spiritual poet Lalan Shah was buried in Kustia close to this river.

Tista is an important river of the northern region of Bangladesh. This trans-boundary river’s name comes from ‘Tri-Srota’ or triple-flows. At present, it accumulates the water of Karotoa, Atrai and Jamuneshwari rivers to Chalanbeel.  It originates in the Chitamu Lake in Sikkim of Himalayas at an altitude of about 7,200 m. and comes down first to Darjeeling plain and then to the Duar plain of West Bengal (India). It enters Bangladesh through the Kharibari border of Nilphamari district. A number of old channels that were occupied by this river and Karotoa  river through which it joined the Padma are still known together as the Buri Tista river or Old Tista.  There is an irrigation dam at the Tista barrage, Hatibandha, Nilphamari on this river, which is the largest of its kind in Bangladesh.

Classification of Rivers

On the basis of characteristics of rivers of the world, scientists have developed several classification systems. Rivers can be classified by its living things (Biotic status), its physical shape, and features (Topography), for recreational purposes (whitewater), and by the Strahler Stream Order.

Biotic Classification

Biotic classification identifies the sensitivity to and recovery time from environmental disturbances of specific habitats. A microhabitat is considered as highly sensitive to disturbance, but has a quick recovery time. In contrast, wetlands are less sensitive to disturbance, but require a longer period to recovery from the effects of an environmental disturbance.

Biotic classification refers to the type of ecosystem found in a particular river. This classification includes the purest, cleanest rivers as well as the most contaminated. One common system divides rivers into 3 principal zones: potamon, rhithron, and crenon.

The Potamon zone describes the downstream area of a river. Most of the plain land rivers of Bangladesh fall in to this category.  This area of river has slower water flowing speeds, its temperature is generally warmer than other areas of the river. In some state the potamon zone is characterized by a sandy river bed and lower oxygen content.

The Rhithron zone describes the upstream area of the river. It is characterized by faster and more turbulent flowing speeds.  Most of the rivers of hilly region of Bangladesh (Greater Sylhet and Chattogram hill tracts, Cox’s Bazar etc) are fallen in this category.  These rivers flow faster and the water temperature is relatively cooler with a higher oxygen level than the potamon.

The Crenon zone describes the area near the origin of the river. This zone is suBangladeshivided into the eucrenon, which is the spring zone, and the hypocrenon, which is the headstream zone. Very few of the hill rivers of Bangladesh including tip of the origin of Halda river is under this zone.  This is where the river gets its start, its flow speeds are much slower than those found in the rhithron zone.  This zone has lower oxygen levels and colder temperatures in characterized as seen in the origin of major rivers of Bangladesh, specially Padma (Ganges) river, Brahmaputra river in mount Everest area of Tibet, Nepal and India and Surma river from Barak river of Meghalaya hills of India.

The Stream Order

The dendritic arrangement of the channels of a river throughout its drainage basin is well known. Several suggestions for ranking streams forming this type of pattern have been proposed. The most widely accepted is that whereby streams are categorized according to order in a hierarchy defined as follows: first-order streams are those having no tributaries, second-order streams are formed by the union of two first order streams, third order streams by the union of second order streams and so on. In its original form the system provided for one stream, usually the longest, of each category to be extended headward in such a way that the main channel of the river extends continuously from source to mouth (Horton, 1945) (see Fig. 1 and 2). Later modifications of the system suppressed this idea in favour of the more simple classification of all streams of the same order into one class (Horton 1945; Strahler, 1952 ).

Schematic representation of stream order in river systems (1, shows the origin of flow)

Schematic representation of stream order in river systems

Figure 1. Schematic representation of stream order in river systems (1, shows the origin of flow)

Topographic Classification of Rivers

Topographic classification refers to the physical makeup, shape, and features of the river. Rivers fall into 1 of 3 categories: Bedrock, Alluvial, or a mixure. In Bangladesh we do not have Bedrock Rivers.  Most of the rivers are Alluvial that are characterized by the presence of floodplains (the land next to rivers that is frequently flooded) and channels (the river route) that have been formed in loosely consolidated sediment. Flooding is an important component of alluvial rivers as it maintains the primary route filled with water and allows for the formation of oxbow lakes, side channels, and wetlands. As alluvial river water flows, it erodes the banks of the river and deposits the resulting sediment into the floodplains or sandbars in the middle of the river. These rivers are further categorized by the pattern of their water flow – in other words, the direction the river flows in. These classifications include: wandering, straight, braided, meandering, and anastomose. The habitats within alluvial rivers range from deep pools to shallow and turbulent waters. In Bangladesh, all oxbowlakes are created in Jashore-Kustia area.  There been several thousand of wetlands in Bangladesh called beels.  Challan beel is one of the notable beel of Bangladesh.  There are many beels in Sylhet region. They combine to create haors.  The list of haor is given in Table 1.  A large man-made artificial lake was created in 1960 at Kaptai UZ of Rangamati district for hydroelectric power generation.

Mixed Bedrock-Alluvial rivers, as the name suggests, combine the previous features. These rivers flow through layers of bedrock and areas of deep alluvial deposits.  Rivers of the Eastern hill region like Sangu, falls under this category.

Chronological Classification

Researchers are able to determine the age of rivers by studying their erosion patterns. For example, young rivers are characterized by their rapid flow, lack of tributaries, and deep rather than wide channels. Mature rivers have less steep grades than the young rivers and are characterized by the presence of several tributaries and a rapid discharge speed. The river Meghna can be classified under this category. Old rivers can be identified by their flood-plains. Finally, Rejuvenated rivers have gradients and are raised by tectonic movement. River Teesta and Old Brahmaputra fall under this category.

White-water Classification

In addition to being important components of healthy ecosystems and a source of freshwater resources, rivers also provide recreational opportunities around the world. One of the most popular river activities is whitewater rafting, or navigating the river in boats and over a wide variety of waves and speeds. In order to prepare for a rafting trip, knowing the whitewater classification is important. The International Scale of River Difficulty includes 6 classifications. Bangladesh still does not have such rivers.

• Class I: River difficulty is easy with fast flow and small waves.
• Class II: River difficulty is novice with wide rivers and medium-sized waves.
• Class III: River difficulty is intermediate with irregular waves that can take over a canoe.
• Class IV: River difficulty is advanced with powerful waves, holes, and restricted passages. These rapids require fast boat handling and the risk of injury to swimmers is considered moderate to high.
• Class V: River difficulty is expert with violent waves, dropoffs, and complex passages. These turbulent rapids continue for long distances before calmer pools are reached.
• Class VI: River difficulty is extreme and exploratory; it is considered extremely dangerous. These rapids come with a high possibility of error and are so difficult to navigate that rescue may be impossible.

Strahler Stream Order

Proposed in 1952, the Strahler Stream Order is based on the Strahler number, which is used to demonstrate the complexity of branching numbers. It applies this same concept to rivers and creates a type of pyramid order based on tributary numbers. The order classifications range from the 1st order to the 12th order. Headwaters, for example, belong to the 1st order, while the Amazon River belongs to the 12th. Researchers have determined that approximately 80% of the world’s rivers and tributaries belong to the 1st and 2nd orders. These waterways are typically located on steep inclines from which they flow downward at a quick pace until joining the next order of waterway. The larger the order number, the larger and slower the river.

Bangladesh Scenario

National Water Management Plan (NWMP) has divided Bangladesh into 8 hydrological regions: North West, North East, North Central, Eastern Hills, South West, South Central, South East and Rivers & Estuary. The BWDB arranged the rivers of Bangladesh into 6 hydrological regions: North West, North Central, North East, Eastern Hills, South East and South West. BWDB combined the South Central and South West region as designated in the NWMP to form the South West region. All the rivers of the country are covered within these 6 regions. The regions are bounded by the major rivers like the Jamuna, the Padma, the Meghna, the old Brahmaputra, etc. All the river systems ultimately fall into the Bay of Bengal. The area wise (Map, see below) distribution of the hydrological zones are given in Table 1.

A brief description of the 6 Hydrological regions are given below:

North West Hydrological Region:

The North-west Region consists of highlands of Bangladesh.  In total 8 districts of Rajshahi division and 9 districts of Rangpur division. The region is bounded by the Brahmaputra-Jamuna in the east and the Padma in the south. There are 115 rivers including 19 transboundary rivers in this region (BWDB, 2005). Along with the two major rivers i.e. Brahmaputra-Jamuna and  Padma, additional Atrai, Dharla, Teesta, Dudhkumar, Karatoya, Mahananda, are significant in many ways. All of them are biotically potamon in nature. The names of rivers of the region recorded by  BWDB (2005) is given in Box 1.

Box 1.

Rivers of North-West Hydrological Region of Bangladesh (BWDB, 2005). 

The * denotes the trans-boundary rivers.

Akhira-Maccha,  Atrai, Atrai (Dinajpur), Atrai (Naogaon-Natore)*, Atrai (Pabna), Alai, Alai Kumari (Burail), Ichamati (Dinajpur), Ichamati (Pabna), Ichamati (Bogura), Ichamati (Bogura-Sirajganj), Iramati, Karatoya*, Karatoya (Nilphamari), Kageshwari, Katakhali (Gaibandha), Kala, Kalapanim Kaludaha, Kumlal-Nautara, Kurum, Kulik*, Khar Kharia-Tilai, Khalsadingi, Gadai, Gaveshwari, Ganges (Padma)*, Gangnai, Gidari, Girai, Guksi, Gobra, Gohala, Garaiya Khal, Ghaghat, Ghirnai, Ghoramara*, Chawai, Chiknai, Chikli, Ciri, Chhiri, Chungabhanga, Satnai, Choto Dhepa, Choto Jamuna, Choto Sinua, Tangon*, Dahuk*, Dhepa, Talma*, Teesta*, Teesta (Panchagarh), Tirnai (Thakurgaon), Tirnai (Panchagarh), Tulshi Ganga, Dudhkumar*, Deonai-Charalkata-Jamuneshwari*, Dharla*, Dhaijan, Dhum, Narth, Nalshisa, Naleya, Nagar Upper*, Nagar Lower (Bogura-Natore), Narode, Palimari, Pagla*, Patharghata, Pathraj, Punarbhaba*, Petki, Fakirni, Phulkumar, Brahmaputra-Jamuna*, Baral Upper (Baral-Nandakuja), Baral Lower (Pabna), Bangali, Badai, Barnai, Banni, Burail, Bullai, Burikhora, Buri Teesta*, Berong, Belan, Besani, Borka, Bhadai (Bogura), Bhulli, Versha, Mahananda Upper  Panchagarh)*,Mahananda Lower (Nawabganj), Maila, Maldaha, Musakhan, Monas, Jamuna (Panchagarh), Ratnai (Lalmonirhat), Ramchandi, Rakhasini-Tetulia (Tulai)*, Lenga, Lona, Shib, Sati-Sarnamati-Bhateshwari, Shemlajan, Shirmakhali Khal, Singimari, Sui, Sinua, Shoz, Harabati, Hura Sagor.

Hydrological Map of Bangladesh

North East Hydrological Region:

The region consists of most the Haor wetland areas, which are Sunamganj, Sylhet, Maulvibazar, Habiganj, Netrakona, and parts of Sherpur, Mymensingh, Kishoreganj and Brahmanbaria districts. There are eighty seven rivers including 20 transboundary rivers in this region. The Indian Barak River reaches the border with Bangladesh at Amalshid in Sylhet district and bifurcates to form the steep and highly flashy rivers the Surma and the Kushiyara. Except some distance one, most of these rivers are in rhithron zone.  The names of rivers of the region recorded by BWDB (2005) are given in Box 2.

Box 2.

Rivers of North-East Hydrological Region of Bangladesh (BWDB, 2005).

The * denotes the trans-boundary rivers.

Atrakhali, Abua (Nandia Gang), Amri Khal, Isdhar Khal-Barbhanga, Updakhali, Umiyam*, Karnajhora, Kharno-Balja*, Koris, Kacha Matia, Kapna, Kamarkhal, Kamarkhali, Kaldahar-Kanyakul, Kalni, Kalapani Jhora, Kushiyara*, Korangi, Khazenchi, Khasimara, Khepa, Khowai*, Gumai, Ghagtia, Ghanura-Bagala (Bukha), Ghora Utra, Chamti, Chitalkhali*, Chela, Jaflong-Dauki, Jalia Chara (Bholaganj), Jalukhali (Chalti)*, Juri*, Dauka, Dhala*, Dudhda, Dolta, Dhanu, Dhalai-Bishnai, Dhalai (Maulvibazar)*,Nokla-Sundrakasi, Narasunda, Naljur, Noya Gang (Khasiamara)*, Naya Gang (Jaintiapur), Netai*, Patnai Paikartala, Pabijuri-Kusi Gang-Kusiya,  Piyain (Sylhet-Sunamganj)*, Piyain (Sunamganj-Netrakona), Old Surma, Pora Khal-Khaiya, Botor Khal, Bar Gang, Baulai (Balua), Bathail, Baloi, Bijna-Guinggajuri, Bibiana, Bekra, Betair, Bedori Khal, Bhabna-Bashia-Bahia Gang, Bhogai Kangsho*, Magra, Manu*, Mora Surma, Moharoshi, Mohasingh,  Malijhi, Mirgi, Jadukata-Rakti*, Lungla*, Lain, Lauranjani, Lubha,  Saiduli-Baruni, Satar Khali, Sari Gowain*, Sinai, Singua, Sutang*, Surma, Sonai-Bordal*, Someswari*, Someswari (Dharmapasha), Someswari (Sreebardi-Jhenaigati).

North Central Hydrological Region:

The North Central Region is bounded by the three major rivers viz. Brahmaputra-Jamuna in the west, the Padma in the south, the upper Meghna River in the south-east and the old Brahmaputra in the north-east. The region consists of 8 districts including the Capital Dhaka. The region has 61 rivers including 1 transboundary river. Among these rivers, the rivers Padma, old Brahmaputra, Sitalakhya, Dhaleswari, Buriganga, Kaliganga, Bangshi, Turag and Balu are important rivers. Some of the rivers are noted for high pollution level and all rivers are in potamon zone. The name of rivers of the region recorded by BWDB (2005) is given in Box 3.

Box 3.

Rivers of North Central Hydrological Region of Bangladesh (BWDB, 2005).
The * denotes the trans-boundary rivers.

Aiman-Akhila, Aiman-Mobari, Arial Khan (Narsingdi), Ichamati (Manikganj), Ichamati (Serajdikhan), Ilishmari, Alongjani, Katakhali, Kaliganga (Manikganj), Khiro (Trishal), Khiro (Bhaluka), Gangdubi, Gazikhali, Goallar Khal, Chatal, Chapai, Chilai, ,Joypara Khal, Jharkata, Jinjiram*, Jhinai, Tungi Khal, Tanki Khal, Taltala Khal, Turag, Tulashikhali Khal, Dhaleswari, Nagda Khal, Nangla, Naljuri Khal, Nangli, Padma, Pagaria-Shila, Paruli Khal, Paharia, Old Dhaleswari, Old Brahmaputra, Pungli, Bangshi, Bangshi (Savar), Brahmaputra (Narsingdi-Munshiganj), Baksatra, Bajja-Medhua, Banar Upper, Banar Lower, Balu, Buriganga, Bairan, Boshkhalir Khal, Mora Jinjiram, Mahari, Menikhali, Labundha, Louhajang, Sitalakhya, Saldha, Suti, Sutia, Sonakhali Khal, Hai, Haridoya.

Eastern Hills Hydrological Region:

The physiography of the Eastern Hills Region is different than that of the other regions of the country. The high altitude nature of the region causing fewer rivers than the others.Over the hundreds and thousands of years, most ofthe rivers of Bangladesh has changed its course. But the rivers of this region has not changed that much. There are 16 rivers in this region. The region has 3 transboundary rivers with Myanmar. The region is separated from Myanmar by the Tuilanpui (Shajal Lui) River. The rivers Karnafuli, Shangu, Matamuhuri, and Naf are some of the major rivers in this region.  Except some crenon zone distribution, most of these rivers are in rhithron zone. The names of rivers of the region recorded by BWDB (2005) is given in Box 4.

Box 4.

Rivers of Eastern Hills Hydrological Region of Bangladesh (BWDB, 2005).
The * denotes the trans-boundary rivers.

Ichamati (Rangamati), Eidgoan, Karnafuli, Kasalang, Chingri (Chengi), Dolu Khal-Tankabati Khal, Naf*, Bura Matamuhuri, Bakkhali, Bharuakhali Khal, Bholakhal, Maini, Matamuhuri*, Rangkhaing, Sangu*, Halda.

South East Hydrological Region:

This is a small pocket area in south-east Bangladesh with 24 rivers including 9 trans-boundary rivers in this region. Thetrans-boundary Rivers originating in India enters Bangladesh and discharges into the Meghna River. Along with the Meghna, the rivers Shalda, Titas, Feni, and Gomti etc. are some of the important rivers of this region. The names of rivers of the region recorded by BWDB (2005) are given in Box 5.

Box 5.

Rivers of South East Hydrological Region of Bangladesh (BWDB, 2005).
The * denotes the trans-boundary rivers.

Arsi-Nalia , Kakri*, Kasti, Gomti*, Ghungghur, Little Feni, Dakatia, Dasadia, Titas, Titas (Narsingdi Sadar-Bancharampur), Dhanagoda, Feni*, Bijni*, Buri, Vulua, Mahuri*, Meghna (Upper), Meghna (Lower), Lahar, Longon, Bolvodra, Salda*, Selonia*, Sonai*, Hawra*.

South West and South Central Hydrological Region:

This region includes the mangrove wetland the Sundarbans reserve forest.  There are 102 rivers including 5 transboundary rivers in this region. The region is bounded by the Padma in the north, the Meghna Lower River in the east and the Bay of Bengal in the south. The rivers Arial Khan, Bhairab, Garai, Kumar, Rupsa etc. are some of the important rivers of this region. The names of rivers of the region recorded by BWDB (2005) are given in Box 6.

Box 6.

Rivers of South West Hydrological Region of Bangladesh (BWDB, 2005).
The * denotes the trans-boundary rivers.

Atharbanki, Arial Khan, Atai, Andarmanick, Afra, Arpangasia, Ichamati-Kalindi*, Kacha, Kapotakshi, Kumar (Chuadanga), Kumar (Faridpur-Gopalganj), Kumar (Upper), Kumar (Lower), Koyra, Karulia, Kankshiali, Kazibacha, Katakhali (Narail), Katakhal (Tungipara), Kaliganga (Pirojpur), Kirtonkhola, Khairabad, Kholpetua, Garai, Gunkhali, Galghasia (Gutia Khali), Gulisakhali, Ghagar, Ghasiakhali, Chatra, Chunkuri, Chandana-Barasia, Chatkhali, Chitra (Chuadanga), Jhap Jhapia, Tarki, Tiakhali, Dhaki, Tetulia (Barisal), Teliganga-Ghengrail, Daratana-Poylahara, Darir Gang, Deluti, Nunda-Otra, Nabaganga, Naria Khal, Nehalganj-Rangmatia, Patuakhali, Putimari, Old Passur, Passur, Pandab, Panguchhi, Palang, Fatki, Bogi, Burirswar-Payra, Baleswar, Badurgachha, Bishkhali, Bisarkand-Bagda Khal, Bishnu-Kumarkhali, Begabati, Betna*, Belua, Bhadra, Bhubaneswar, Bhairab, Bhairab (Bagerhat)*, Bhairab-Kobadak, Bhola (Bagerhat), Mongla, Mukteshwari Teka, Madhumati, Morirchap-Labangabati, Mathabhanga*, Madar Gang, Madaripur Bil Route, Malancha, Minaj, Rupsa (Khulna), Rabnabad, Raimangal*, Lohalia, Sakbaria, Satla-Harta-Natherkanda, Saildaha, Sibsa, Solmari, Sugandha, Shaynda, Soya-Harinbhanga, Shapmara-Habra (Khutikkhali), Salta, Sirajpur Haor, Hari, Harihar, Hamkura, Haria, Haparkhali, Habarkhali, Hisna-Jhanja.

River Biodiversity

Rahman (2005) updated fish list for Bangladesh as 265 Species and most of these found in the open water wetlands and river ecosystem (Table 2).  The recent IUCN red list assessment showed that 64 Species are threatened category, of which 9 Species are Critically Endangered (CR), while 30 Species are Endangered (EN) and 25 Species are Vulnerable (VU) (Table 2). It is alarming that, 40 Species are Data Deficient (DD) and the number of fish Species assessed was only 253. There is an urgent need of policy making, for the management of rivers in the country (Naser 2016) to protect these fishes and their habitats.

Table 2

The Freshwater Fishes of BANGLADESH (Rahman 2005) and their IUCN Red List (IUCN BANGLADESH 2015) Status.

(Some of the orders are separated due to taxonomical reasons by the author).

 ¹Order is separately shown in Rahman (2005) but in IUCN Red list (IUCN Bangladesh 2015) kept under family Channidae, order Perciformes;   ²Orders are separately shown in IUCN Red list (2015);  ³Shown as suborder of Perciformes in Rahman (2005);  ⁴Shown as suborder of Cypriniformes in Rahman (2005);  ⁵Shown as suborder of Clupeiformes in Rahman (2005).

Conclusion

Rivers play a vital role in Bangladesh geomorphology, culture, heritage, and biodiversity. The conservation of rivers and their eco-ethological and physiographic aspects are very necessary for a country’s endemic ecosystem and economic growth. As a great population of this country led a river-based life for their livelihood and economy; the future protein sources and agricultural outfit of the country mostly depend on a better planning, giving riverine economy the most priority. Above all, to maintain a sustainable nature based economic growth in the country, a transboundary agreement for the use of rivers and their resources is most essential (Naser 2016).  This will help the region form the Himalayan Nepal to the hilly Indian states and the plainland Bangladesh in future ahead.

References:

1. Banglapedia 2012. Banglapedia- the National Encyclopedia of Bangladesh, Asiatic Society of Bangladesh, Dhaka Bangladesh. Web version. http://en.banglapedia.org. accessed on 12.1.2019.
2. 2005. Rivers of Bangladesh. In Bengali. Bangladesh Water Development Board. Dhaka, Bangladesh, 621p.
3. Horton, R.E. 1945. Erosional development of streams and their drainage basins: hydro-physical approach to quantitative morphology. Geological society of America bulletin 56 (3): 275- 370.
4. IUCN Bangladesh. 2015. Red List of Bangladesh Volume 5: Freshwater Fishes. IUCN,. International Union for Conservation of Nature. Dhaka, Bangladesh. 360p.
5. Naser, M.N. 2016. Transboundary issues for protecting diversity of fish and fisheries in rivers of Bangladesh. Chapter 8, in Giri S.S. ed. Policy Framing on Fish Biodiversity Management in Transboundary Rivers of South Asia. SAARC Agriculture Centre, Dhaka, Bangladesh. 125-142pp.
6. Rahman, A.K.A., 2005. Freshwater fishes of Bangladesh, second edition. Zoological Society of Bangladesh, Department of Zoology, University of Dhaka, Dhaka-1000. 394p.
7. Strahler, A.N. 1952. Hypsometric (area-altitude) analysis of erosional topology. Geological society of America bulletin 63(11): 1117-1142.

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Conservation Initiative of Endangered Phayre’s Langur (Trachypithecus phayrei)   
– In the North Eastern Forests of Bangladesh

Tanvir Ahmed

Research Assistant, Bangladesh Hoolock Gibbon Project,
Department of Zoology, Jagannath University, Dhaka
Member of IUCN Primate Specialist Group,
Section for Human-Primate Interaction
Email : shaikot2023jnu@gmail.com

Background:

There are 10 Species of non-human primates (here after primates) in Bangladesh – one Species of Loris, five Macaques, three Langurs and one lesser Ape (Brandon-Jones et al.2004; IUCN Bangladesh 2015). Primates are the most threatened group of mammals in the country; 90% of them are threatened. Three Species are Critically Endangered while five Species are Endangered nationally (IUCN Bangladesh 2015).

Phayre’s Langur (Trachypithecus phayrei) is a globally “Endangered” primate (Bleisch et al. 2008) which is “Critically Endangered” in Bangladesh (IUCN Bangladesh 2015). It’s distribution is limited to few south and south-east Asian countries – Bangladesh (Sylhet and Chottogram division), China, India, Lao PDR, Myanmar, Thailand and Vietnam. Gettins and Akonda (1982) estimated 1300 individuals of the Species in Bangladesh while Ahsan (1984) reported 1050 individuals. Molur et al. (2003) concluded the existing population is less than 100 that reveals a sharp decline of more than 80% of its population over it’s the last three generations. However, there is no precise estimation of the population abundance available in Bangladesh. Due to lack of such baseline information, conservation of Phayre’s Langur is not effective, although numbers of protected areas harbor their population in the northeast Bangladesh. To initiate Species specific conservation effort for the Phayre’s langur it is highly required to have insights on their current status, habitat and threats affecting their survival. With the financial support by The Rufford Foundation, UK, a survey was carried out since March 2018 to September 2019 in 5 northeastern forests of Bangladesh with the following objectives:

1. To assess the population status of Phayre’s Langur in 5 northeastern forests of Bangladesh.
2. To assess the threats facing the Langur across the landscape.
3. To promote awareness campaign towards biodiversity conservation ensuring active participation of local communities.
4. To develop management recommendations for the Species.

Study Sites:

Northeastern forests of Bangladesh (Moulovibazar and Habigonj district) is in Sylhet Hills bio-ecological zone (Nishat et al. 2002) and a part of Indo-Burma biodiversity hotspot (Stanford 1991). Our study sites (Satchari National Park, Lawachara National Park, Rema-Kalenga Wildlife Sanctuary, Rajkandi Reserve forest and Patharia Reserve Forest) bound between N24.07 E91.25 and N24.36 E91.13 bordering two Indian states Tripura and Assam. The forests are semi-evergreen in nature consisting of hill forests, shrubs and mixed bamboo vegetation. Topography of these areas is hilly and ranging from 50 to 300 meter above sea level. Numerous streams and swampy areas criss-cross the region. The areas are surrounded by industrial plantation of tea and rubber or agricultural and rural settlement. As s result, the natural forests of the sites had shrank over the last few decades and become fragmented and patchy. Still a few of the globally endangered Species (e.g. Hoolock Gibbon, Phayre’s Langur, Assam Roofed Turtle, White-rumped Vulture etc.) (IUCN Bangladesh 2015) are supported by the forests indicating their conservation importance.

Methodology:

1. Population Survey: Surveys were being carried out in pre-established forest trails, roads and dried streamlines of the forests. A group of 2–5 people walked from approx. 06:00 to 11:00 h and 14:00 to 18:00h with regular short stops to search for the animals. The movement were quiet monitoring a fixed velocity of about 1.5km/h. In detection of Phayre’s Langur, perpendicular distance of the centre of animal group (cluster) in their first detected location were measured from transects (Buckland et al. 2001). Sighting time, GPS co-ordinates, elevation, vegetation type, number of individuals and age-sex composition data were collected.
2. Threats and People’s Attitude Survey: Threats to Phayre’s Langur, local people’s forest use and tourist’s activities into the habitats were noted during field observation. Informal personal interviews by were conducted to determine the context of human-monkey conflict and local people’s attitude towards the Langur and other wildlife in the landscape. A few questionnaires in Bangla were prepared for interviewing fringe villagers, former hunters, poachers and the forest stuffs.
3. Conservation Initiatives: We arranged community consultation meetings, enlightening school going students towards biodiversity conservation, awareness campaigns and publishing news in popular portals towards sustainable conservation of the Species.

 Findings at a glance:

According to complete counting of Phayre’s Langur during distance sampling based population data collection, a total of 376 individuals were recorded belonging to 36 groups in 5 study sites of Northeastern Bangladesh (Figure 1). The mean group size was 10.44 ± 5.37 (4 to 26 individuals). Altogether 47% of all the recorded individuals were adult, of which, 38% were adult males and 62% adult females. Population density following distance sampling base data analysis in each site will be presented later in peer-reviewed articles. About 33% of the recorded population were found in less protected Rajkandi and Patharia Hill Reserve Forest where populations are vulnerable to hunting by local ethnic communities and trading. Moreover, habitat destruction, fragmentation and illegal logging were also found besides unregulated extraction of feeding plants such as Bamboo (Figure 2). Besides, lack of public awareness, poor law implementation, electro-caution and trading for zoos were also recorded affecting population in long term survival.

Figure 1: Phayre’s Langur Population in Northeast Bangladesh

Figure 2: Threats affecting Phayre’s Langur in Northeastern forests

We developed conservation education programs for the local people who are directly or indirectly depends on forests for their livelihood. As an initiative, we focused on building their trusts on project activities, engaging them into awareness campaigns, enriching their understanding of ecosystem services of the forests and the conservation importance of wildlife in their area focusing Phayre’s Langur. Conservation materials were distributed among different communities. We arranged 2 major community consultation programs in Rema-Kalenga Wildlife Sanctuary and Rajkandi Reserve Forest ensuring active participation of local leaders, community people, forest departmental staffs and stakeholders. Our focus was to enlighten the local people about their economic development through primate based eco-tourism development in local scales and encourage them to be trained eco-tourist guide. We helped four local people of different forest sites to develop their skills in this respect. Now they voluntarily collect information of wildlife hunting, trading and other illegal activities into the forests and share with local forest departmental staffs and the project members for necessary steps. In addition, stickers, posters and sponsor logo embedded T-shirts were distributed among forest stuffs, local communities and students.

Conservation Implications:

Ecologically Phayre’s Langur is valuable for the forest regeneration activities through seed dispersals and pollinations. This animal is an important attraction to the tourists; visitors pay the local guides and forest departments to see the animals entering in the protected areas. So, it enables local communities to income generation for their livelihood. But the quick expansion of agricultural activities through lemon gardening, paddy cultivations and monoculture plantation into the protected areas are threatening the Species and other wildlife in the area. Illegal hunting for bush meat and trading for local Zoo have also impacts on the Langur population. This complex situation demands kin attention of Bangladesh Forest Department and NGOs to promote alternative livelihood strategy of local people to decrease their forest dependency. Eagerness of local government and law enforcement authorities can have important steps to maintain the forest’s rules and regulations. Moreover, establishment of more protected areas in Rajkandi and Patharia Hill Reserved forests will be the most important steps. This baseline research findings will help policy makers in decision making and to fix up priorities in conservation of this nationally critically endangered primate.

Conclusion:

Conservation efforts are baffled not to be in the right scale. Besides, success is almost invisible shortly because it requires long term programs. Our initiatives has already stepped forwards making a baseline initiative for sustainable conservation of Phayre’s Langur in Bangladesh. Publishing articles along with management prescriptions are the required further steps to continue. The project members (Md. Sabit Hasan, Shimul Nath, Sajib Biswas and the author) ensure to continue work on the Species collaborating NGOs and resource persons in the field.

 Cited Literatures:

1. Ahsan, M.F. 1984. Study of primates of Bangladesh: determination of population status and distribution of non-human primates in Bangladesh with emphasis on Rhesus monkey. Unpublished M. Phil thesis. University of Dhaka, Dhaka.
2. Brandon-Jones, D., Eudey, A.A., Geissman, T., Groves, C.P., Melnick, D.J., Morales, J.C., Shekelle, M. and Stewart, C.B. 2004. Asian primate classification. International Journal of Primatology 25(1): 97–164.
3. Buckland, S.T., Anderson, D.R., Burnham, K.P., Laake, J.L., Borchers, D.L. and Thomas, L. 2001. Introduction to Distance Sampling. Oxford: Oxford University Press.
4. Bleisch, B., Brockelman, W., Timmins, R.J., Nadler, T., Thun, S., Das, J.and Yongcheng, L. 2008. Trachypithecus phayrei. The IUCN Red List of Threatened Species 2008.
5. Gittins, S.P. and Akonda, A.W. 1982. What Survives in Bangladesh?  Oryx 16(03). DOI: 10.1017/S003060530001752x.
6. IUCN Bangladesh. 2015. Red List of Bangladesh Volume 2: Mammals. International Union for Conservation of Nature, Bangladesh Country Office, Dhaka, Bangladesh, pp. xvi+232pp.
7. Molur, S., Brandon-Jones, D., Dittus, W., Eudey, A., Kumar, A., Singh, M., Feeroz, M.M., Chalise, M., Priya, P. and Walker, S. (eds.). 2003. Status of South Asian Primates: Conservation Assessment and Management Plan (CAMP) Workshop Report, Coimbatore, India.
8. Nishat, A., Huq, S.M.I., Barua, S.P., Khan, A.H.M.A.R. and Moniruzzaman, A.S. (Eds). 2002. Bio-ecological Zones of Bangladesh. IUCN Bangladesh Country Office, Bangladesh, Dhaka, xii + 141pp.
9. Stanford, C.B. 1991. The Capped Langur in Bangladesh: Behavioral ecology and reproductive tactics. Contribution to Primatology. Vol. 26. Basel: S. Karger.

N.B. – Tanvir Ahmed is passionate to primate ecology and conservation. During undergraduate and Master’s degree at Dept. of Zoology, Jagannath Univ., he was involved in studies on Rhesus Macaque, Pig-tailed Macaque and Bengal Slow Loris. At present, he is leading the Phayre’s Langur project, as well as assisting studies on population, ecology and conservation of Western Hoolock Gibbon in Bangladesh.

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Parasitic Infestation in Nandus nandus (Ham.-Buch.)
-A Review with a few Biological Aspects

Dr. Hamida Khanum
Professor, Dept. of Zoology, DU
E.mail. hamida_khanum@yahoo.com

Dr. Sharmin Musa
Professor, Dept. of Zoology, DU
E.mail. sharminsumi@yahoo.com

Md. Rahat Hossain
Dept. of Zoology, DU
E.mail. rahathossaindu1213@gmail.com

Abstract

The commonly known Meni or Bheda fish in Bangladesh, Nandus nandus (Ham.-Buch.), is an important fish-food of high nutritive value in South Asian countries. The natural population of this fish has been declining rapidly due to some parasitic infections, which has escalated due to the lack of scientific management, anthropogenic disturbances, unhabitable water quality, and such related factors. The overall prevalence and intensity of parasitic infestation revealed through different studies were 63.75% (4.53), 71.67% (4.52) and 55% (3.72), recorded recorded till date. But, a relationship between the infestation of parasites and the body length of N. nandus was not found. Those studies had showed that the intestine of the fish was the most susceptible organ and Allocreadium species (73.12 %) was the most abundant parasitic Species.

Introduction

The Gangetic leaffish, Nandus nandus is a fresh and brackish-water bentho-pelagic Species of the family Nandidae. It is distributed throughout the Indian sub-continent including Bangladesh, India, Malaysia, Myanmar, Pakistan, Thailand, and Vietnam (Froese and Pauly 2016). It is very important for its fat but high concentration of protein, lipid, calcium, phosphorus, and other useful elements as human nutrients (Chowdhury 2001). However, unfortunately the natural populations are declining fatally due to reckless fishing, habitat destruction (IUCN Bangladesh 2000) pollution, diseases and other ecological changes to their territory (Hossain et al. 2015c). As a result, this fish is categorized as vulnerable in Bangladesh (IUCN Bangladesh 2000) although globally categorized as least concern (IUCN 2014).

The production and growth of this fish are hampered by various ecological and biological factors and also by diseases and of the factors, helminth parasites play a major role. (Parveen and Sultana 2014). Government statistics show that the per capita fish intake has declined from 12 kg./Annum in 1960 to 6.5 kg./Annum in 1990 indication that fish production could not keep pace with increasing population (Statistical year book of Bangladeh 2010). In N. nandus, parasites infect almost all organs of the host like, gills, skin, fin, intestine, stomach, kidney, and muscles (Hossain 2012). Parasitic infestation is a global thread particularly in the tropics and is therefore an essential area for proper attention to be given by the scientists for sustainable aquaculture production (Chandra 2006). The World Health Organization (2004) has estimated that the number of people currently infected with fish-borne trematodes alone exceeds 18 million, and many more are at risk. According to Parveen and Sultana (2014), the common Species of helminths found in N. nandus of Bangladesh are trematodes (Clinostomum giganticum, C. complanatum and Euclinostomum multicaecum), cestodes (Bothriocephalus species and Senga ophiocephalina), acanthocephalans (Pallisentis nandai, P. ophiocephali and Neoechinorhynchus species) and nematodes (Porrocaecum species, Contracaecum species and Gnathostoma spinigerum). Among ectoparasites, Trichodina species, Chilodonella species, Dactylogyrus species, Ichthyophthirius multifilis and myxosporean spores are found in the gills of N. nandus in winter season (Ahmed et al. 2009).

Methodology

Data was collected through extensive review of literatures from different sources. We used PubMed, Google, Google Scholar, and Research Gate to search relevant information using different keywords. Information from books, other published articles etc. were also used to accumulate data on parasitic infestation in Nandus nandus.

Results

Female individuals of N. nandus showed comparatively higher parasitic infestation than males (Table 1). Prevalence and intensity of parasites do not depend on the different length of N. nandus. Intestine was the most infected internal organ by different parasites followed by body cavity and stomach. The highest prevalence was found for Allocreadium species (73.12 %) in intestine, Clinostomum species (56.25%) in stomach and C. giganticum (22%) in body cavity.

Table 1. Comparartive information of parasitic infestation in N. nandus based on sex.

Table 2. Prevalence and intensity of parasitic infestation in different length groups of host fish Nandus nandus.

Table 3. Prevalence and intensity of parasites in N. nandus based on different organs.

Discussion

All the previous studies done in different times by different researchers suggested a high prevalence and intensity of parasitic infestation. This high prevalence may be associated with lack of scientific management, man-made disturbances, water quality deterioration and many other causes (Ahmed et al. 2009). Parveen and Sultana (2014) and Parveen et al. (2007) separated the samples into male and female groups and found significantly higher prevalence in female (74.07% and 65.21%) than in male (42.31% and 41.17%) respectively (Table-1). Similar results were observed by Sultana (2015), Khanum et al. (2008) and Rahman and Saidin (2011). They concluded that this might be due to lower physiological resistance to female fishes rather than the ecological conditions. This is however not in agreement with Hossain (2012) (unpublished MS thesis), who reported higher (73.53%) prevalence in male than in female (69.23%). This may be due to the difference in the source of fish hosts used in the two studies.

Parveen and Sultana (2014) and Hossain (2012) conducted their experiment on parasitic infestation in Nandus nandus based on organelle distribution and found the highest prevalence of parasites (47.19% and 73.33%) respectively (Table 3) in the intestine. Similar results also observed by Sultana (2015) and Khanum et al. (2011).  For this experiment, Parveen and Sultana (2014) kept the collected endoparasites in 70% ethyle alcohol but Hossain (2012) kept each organ of the host in 0.75% NaCl solution. In the study of Hossain et al. (2017) samples were instantly chilled in ice on site and preserved with 10% buffered formalin upon arrival in the laboratory. Ahmed et al. (2009) preserved the parasites in Alcohol, Formalin and Acetic Acid for detailed study.

The highest prevalence of parasitic infection in N. nandus was in summer and the lowest in winter recorded from the studies of Parveen and Sultana (2014). Lafferty and Kuris (1999) reported that the factor responsible for this is eutrophication. In contrast, Sultana (2015) and Ahmed et al. (2009) found that the prevalence and intensity was higher in winter than in summer and autumn. This may be due to the sudden fall down of temperature and reduced antibody production in winter (Ahmed et al. 2009). Whereas, Hossain (2012) observed that the higher prevalence was in rainy season than in summer and winter seasons.

Parveen and Sultana (2014) separated the host fishes into three length groups and showed the prevalence in small fishes is less than large fishes and the highest intensity in medium length group and lowest in small length group (Table 2). Hossain (2012) separated the host fishes into four length groups and observed the highest prevalence in intermediate length group. Sultana (2015) and Mofasshalin et al. (2012) found the same result. The present study suggests that in N. nandus, age, sex, length, physiology, season of the year and other environmental factors mainly influence the parasitic infestation.

References:

1. Ahmed, G.U., Hossain, M.M., and Hassan, M.M. 2009. Seasonal variation of disease and pathology of a perch, Nandus nandus (Hamilton,1822) from Ox-bow Lake fisheries in Bangladesh. Eco-friendly Agril. J. 2(8): 761-767.
2. Chandra, K.J. 2006. Fish Parasitological Studies in Bangladesh: A Review. Agric. Rural Dev. 4(1-2): 9-18.
3. Chowdhury, M.B.R. 2001. The occurrence of nematode parasites in Nandid fish. Bangladesh J. Agricult. Sci. 10: 37-42.
4. Donald, B. Jyrwa, Thapa, S. and Tandon, V. 2014. Helminth parasite spectrum of edible freshwater fishes and fish-borne zoonoses in Meghalaya, Northeast India. Parasite Dis. 40(2): 312-329.
5. Froese, R. and Pauly, D. 2016. World wide web electronic publication. Available at (http://www.fishbase.org).
6. Hamilton, F. 1822. Fishes of the Ganges. Archibald constable and company, Edinburgh, pp. 96.
7. Hossain, M.I. 2012. Helminth infection in Nandus nandus and Colisa fasciatus. MS thesis, Department of Zoology, University of Dhaka, pp. 54-89.
8. Hossain, M.Y. 2014. Threatened fishes of the world: Mystus vittatus (Bloch, 1794) (Siluriformes: Bagridae). J. Fish. 72: 183-185.
9. Hossain, M.Y., Hossan, M.A., Khatun, D., Nawer, N., Parvin, F., Rahman, O. and Hossain, A. 2017. Growth, condition, maturity and mortality of the Gangetic Leaffish Nandus nandus (Hamilton, 1822) in the Ganges River (Northwestern Bangladesh). Jordan J. Biol Sci . 10(1): 57-62.
10. Hossain, M.Y., Hossan, M.A., Pramanik, M.N.U., Nawer, F., Ahmed, Z.F., Yahya, K., Rahman, M. M., and Ohtomi, J. 2015c. Threatened Fishes of the World Labeo calbasu (Hamilton, 1822) (Cypriniformes: Cyprinidae). J. Fish. 73: 134-136.
11. IUCN Bangladesh. 2000. In: Red Book of Threatened fishes of Bangladesh. The World Conservation Union, Dhaka, Bangladesh, pp. xi+116.
12. 2014. In: Red List of Threatened Species. Available at (https://www.iucn.org/red-list).
13. Kabata, Z. 1985. Parasites and diseases of fish cultured in Tropics. Taylor and Francis Ltd, London, pp. 318.
14. Khanum, H., Bugum, N. and Begum, A. 2008. Infestation of helminth parasites in the Panna micrdon ( Bleeker , 1849). Dhaka Univ. J. Biol. Sci. 17(1): 51-57.
15. Khanum, H., Bugum, N. and Begum, A. 2011. Seasonal prevalence, intensity and organal distribution of helminth parasites in Macrognathus aculeatus. Dhaka Univ. J. Biol. Sci. 20(2): 117-122.
16. Lafferty, K.D. and Kuris, A.M. 1999. How environmental stress affects the impacts of parasites. Oceanogr. 44: 925-931.
17. Margolis, L., Esch, G.W., Holme, J.C., Kwis, A.M. and Schad, G.A. 1982. The use of ecological terms in parasitology (Report of an adhoc committee of the American Society of Parasitology). J. Parasitology. 68(1): 131-133.
18. Mofasshalin, M.S., Bashar, M.A., Alam, M.M., Alam, G.M., Moumita, D., Mazlan, A.G. and Simon, K.D. Parasites of three Indian minor carps of Rajshahi, Bangladesh. Asian J. Anim. Vet. Adv. 7(7): 613-620.
19. Nahida, T.K., Khatun, A. and D’silva, J. 1994. The histopathology of infested organs in Nandus nandus (Hamilton). Ninth Zool. Conf. Bangladesh, pp. 51-54.

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Bats of Bangladesh  
-The Flying Mammals of the Dark

Prof. (Dr.) A N M Aminoor Rahman

Head of the Dept. of Gynecology,
Obstetrics, & Reproductive Health
Director (Outreach Center)
Former Dean, Faculty of Veterinary
Medicine & Animal Science, BSMRAU, Gazipur-1706
E.mail. aminoor69@yahoo.com

Mammals, are the most intelligent vertebrates, which have well-adapted over the last millennia,  distributing over and very successfully inhabiting almost all the habitats of the world, ranging from the Arctic to the Antarctic region. This highly developed chordate have traversed the land, water and sky, inhabiting anywhere of these biomes from the trees to the ocean. Their morphological evolution has allowed them to adopt various methods of locomotion, from flying to swimming and to become arboreal or fossorial, inhabiting the land, fresh water, or marine habitats.

All mammals possess four unique characteristics, like – i. The presence of mammary glands – functional in suckling females but non-functional in others (vestigial in males); ii. The presence of a neo-cortex (a part of brain); iii. The presence of hair all over the body; and iv. The presence of a Pinna (outer part of ear) and three Ossicles in the middle ear (Malleus, Incas, and Stapes). Besides, a few other unique characteristics are found in some mammals but not all. They are warm blooded or endothermic animals (except naked Mole Rat). Their five Species are oviparous (egg-laying, Monotremes), but others are viviparous (give birth to babies) and have a placenta for feeding and growing of the fetus during gestation.

Among the mammals, bats are the only group capable of true flight. With extremely elongated fingers and a wing membrane stretched between, the bat’s wing anatomically resembles the human hand. Out of 5,676 living mammalian Species worldwide bats represent about 22%, with about 1,240 Species. In Bangladesh, out of 129 Species of mammals bats represent 27.9%, with about 36 Species. They are also among the only mammals known to feed on blood. Common misconceptions and fears about bats have led many people to regard them as the creatures of dark and unclean disease carriers. Therefore, bats are always hated and neglected in many countries including Bangladesh. The myths those are known to many countries including our motherland about bats are mostly exaggerated. But they are actually very helpful and performing the vital ecological roles of pollinating flowers and dispersing fruit seeds; many tropical plant Species depend entirely on bats for the distribution of their seeds. They are also controlling the population of crop-destroying insects.

Bats are mammals of the order Chiroptera. The word Chiroptera derived from the ancient Greek word cheir means “hand” and pteron means “wing”, which means their forelimbs form webbed wings, making them the only mammals, naturally capable of true and sustained flight. In contrast, some other mammals can also occasionally fly, like the gliding of Opossums for a short distance. Bats do not flap their entire forelimb like birds, instead they flap their spread-out digits, which are very long and covered with a thin membrane, Patagium. The Chiroptera is divided into two sub-orders: 1) Macro-chiroptera, popularly known as Megabats, which are less specialized and largely fruit-eating, commonly known as flying fox, and 2) Micro-chiroptera, popularly known as Microbats, which are highly specialized and echo-locating bats. Megabats tend to be larger than microbats, but some microbats are actually larger than some megabats. About 70% of bat Species are insectivores and most of the rest are frugivores (fruit eaters). A few Species, such as the fish-eating bat, feed from animals other than insects, along with Vampire bats, which are haemato-phagous (feeding on blood).

The largest Species of bat is the Giant Golden-crowned Flying Fox with a weight up to 1.6 kilogram (kg) and wingspan up to 1.7 meter (m). The smallest bat in the world is the Kitti’s Hog-nosed bat which is only 30-40 millimeter (mm) long, 15 mm wingspan and weight is only 2.0-2.6 gram (g). It is also the smallest mammals of the world with the Etruscan Shrew being the other contender. Out of 35 known Species of bats in Bangladesh, Flying Fox (Pteropus giganteus) is the largest which is 23-25 centimeter (cm) long. Its wingspan is 1.2-1.5 m and weight is 0.6-1.6 kg. On the other hand, Least Leaf-nosed Bat (Hipposideros cineraceous) is the smallest bat as well as mammals of Bangladesh which is only 3.7 cm long.

Bats live all over the globe, with the exception of extremely cold regions. They mostly prefer warmer areas that are closer to the equator, and can be found in rain forests, mountains, farmland, woods, and cities. Bats have two strategies for weathering the cold. Some migrate to warmer areas, while others go into torpor. In this short-term form of hibernation, a bat reduces its metabolic rate, lowers its body temperature, and slows its breathing and heart rate. Except their ecological roles bats are economically important, as they consume insect pests, reducing the need for pesticides. They live in crevices, tree hollows, furrows in rocks and walls, caves, abandoned buildings, under the bridges and road culverts, large trees and old wells. Under each roosting place there are usually be a pile of droppings that stink. The same roost is used for ages’ unless disturbed. Bats live together in groups called colonies, which contain 100-1,000 or more bats. They are also nocturnal, meaning that they sleep during the day and are awake at night. Some may fly up to 50 kilometers (km) to find food during their nightly journeys. In the day, they sleep upside down from trees or the roofs of caves, holding on with their sharp claws.

Bats have a keen sense of smell and sound. All fruit bats except the Egyptian Fruit Bat use the sense of smell and vision for locating food and shelter while all the insect bats and the Egyptian Fruit Bat use echolocation. The nose of many Species has become modified and works as a sensory organ. Echolocation is a remarkable phenomenon in the animal world. Insect bats have a perfect mechanism of echolocation. The insect bats produce high frequency, supersonic sound waves through the mouth or the nostrils. The Egyptian Fruit Bat produces the sound with the help of the tongue. These sound waves hit objects such as the prey or obstacles and will rebound as echoes that are picked up by the bat ears. Insect bats have an acute sense of hearing.

Most bats eat flowers, fruits, nectar, pollen, leaves, and different types of small insects, though it depends on the type of bat. Megabats usually eat fruits, and microbats generally eat insects. The Malayan Flying Fox has a big appetite. It can eat half its body weight every day. The Vampire Bat outdoes even that, though, eating twice its weight in one day. The Brown Bat can eat up to 1,000 small insects in an hour. Some bats will squeeze fruits in their mouths and drink the juices. Vampire Bats like a juice of a different type, though. They do indeed drink blood, mainly from cattle and deer, but they don’t suck blood, like the legends say. Rather, they make a V-shaped cut and then lick up the blood.

Bats have some unique mating behaviors not seen in other animals. Male and female bats meet in hibernation sites, called hibernacula, where they breed. Bats ‘swarm’ around in huge numbers, chasing each other and performing spectacular aerobatics. It’s not clear how the bats choose their mates, but it may be that females seek out the most agile males. During the swarming event, breeding pairs go off to secluded spots in the cave to mate in private.  A pregnant female carry her offspring for a gestation period of 40 days to 6 months. Then, she gives birth to one offspring, called a pup. The pup usually weigh about one-fourth as much as its mother at birth. Soon after birth the offspring crawls up the mother’s body till it reaches one of the two pectoral nipples; it hold on to the nipple till the time of weaning. All baby teeth are of the same size and used just for getting a good grip on to a teat. Young bats drink milk from their mothers to survive, much like other mammals. The mothers and pups stay in groups, separate from the males. The other mothers help take care of the pup until it is old enough to care for itself.

The classification or taxonomy of bats, according to the Integrated Taxonomic Information System (ITIS), is therefore:

• Kingdom: Animalia
• Phylum: Chordata
• Subphylum: Vertebrata
• Class: Mammalia
• Order: Chiroptera
• Suborder: Macrochiroptera, Microchiroptera
• Family: There are 16 families in the suborder Microchiroptera, and only one in Macrochiroptera: Pteropodidae, which includes flying foxes and Old World fruit bats.
• Genera: There are 187 genera of bats.
• Species: There are more than 950, and perhaps as many as 1,240 Species of bats.

Bats constitute the largest mammalian community in Bangladesh; however, till today little population data on fruit bats is available while data on population of other insectivorous bats is very scanty. Some of the bat Species found in Bangladesh is described below:

1. Flying Fox (Pteropus giganteus, Family: Pteropodidae):

Also known as Indian Flying Fox, Indian Fruit Bat or Greater Indian Fruit Bat. Bangla name is Boro Badur, Badur, or Chompa Badur. Body length 23-25 cm, has no tail, wingspan 0.6-1.6 m and weight 1.2-1.5 kg. This is the biggest and most conspicuous of all bats found in the country. Head is deep chestnut-brown, neck and back are chestnut-brown, and belly is dark yellow-brown. Wings are huge and black with a long claw in the first digit of forearm. Feet are large with claws in all five digits. Long ears are black. Flying Foxes are nocturnal and crepuscular and live in colonies of hundreds or thousands of individuals. Diet consists of fruit juices like litchi, mango, guava, fig etc. They mainly roost in large trees such as banyan, fig, tamarind etc. Breeds year round; mating occurs from July to Oc­to­ber and births take place from Feb­ru­ary to May. They are polyg­y­nan­drous that is female mate with different males. After 140-150 days of gestation female gives birth to 1-2 offspring. Young become mature after 1.5 years. Lifespan is up to 31 years in captivity. Flying fox is very common and is widely distributed throughout the country in all types of habitat.

2. Fulvous Fruit Bat (Rousettus leschenaultia, Family: Pteropodidae):

Also known as Leschenault’s rousette. Bangla name is Kolabadur or Tamatey Kolabadur. Length 10-11 cm and weight 60-100 g. Newborn weigh only 12 g. Fur on the upper part of the body is fulvous-brown and in the under part is gray or grayish-brown. Long hairs are seen on chin and neck. Rest of the body fur is short and sparse. They are nocturnal and lives in colonies of 2-3 thousands or more individuals. Diet includes different types of fruits including banana. Day time roosts include caves, deserted buildings, disused tunnels etc. Information on breeding is scanty, but may breed 1-2 times a year. Young weaned in 35-40 days. Female and male may attain sexual maturity in five and fifteen months, respectively. Lifespan is not known. They are common and distributed almost throughout the country including the Sundarbans.

3. Short-nosed Fruit Bat (Cynopterus sphinx, Family: Pteropodidae):

Also known as Greater Short-nosed Fruit Bat. Bangla name is Boncha Kola Badur, Boro Boncha Kola Badur, Boncha Nak Kola Badur or Boro Boncha Nak Kola Badur. Body length 10 cm, wingspan 48 cm and weigh only 63.5 g. Newborn is 13.5 g with a wingspan of 24 cm. This medium-sized bat has a rela­tively long snout. Fur is very fine and silky. Upper part of the body is bright orange or brown to grey-brown with paler un­der ­part. Juveniles are lighter than adults. They are nocturnal and crepuscular. Diurnal roosts include tents made by males with leaves and stems, the underside of palm leaves, the crevices of banyan, peepul, palm or coconut tree etc. Their diet includes fruits mainly banana, guava and mahua; but also eat flowers and leaves. They live in agricultural lands to forested regions, grasslands, or mangroves. They breeds twice a year; mainly during February to March and August to September. After 3-5 months of gestation, female give births to a single offspring. Female become sexually matures in 5-6 months and male in a year. Lifespan is up to ten years in captivity. They are common and widely distributed throughout the country in diverse habitat.

4. Lesser Mouse-tailed Bat (Rhinopoma hardwickii, Rhinopomatidae):

Also known as Hardwicke’s Lesser Mouse-tailed Bat, Lesser Rat-tailed Bat or Long-tailed Bat. Bangla name is Choto Indurleji Chamchika or Choto Indur Leja Badur. This is a small bat with a very long, mouse-like tail. Body length is 6.2-7.1 cm, tail 5.7-7.0 cm and weight 6-14 g. The fur is usually brown-gray, tending towards darker brown on the back and lighter grey on the underside. Face is furless with black eyes and a flat, thin snout. Ears are large in proportion to the head. The long, thin tail is only partially enclosed within a flap of skin, known as the tail membrane. These nocturnal and crepuscular bats roosts both in small (4-10) and large (up to 500) groups and eats mainly insects, especially beetles, moths etc. They live in hot and dry climate. Roosting sites include dry scrub, rocky areas, caves, abandoned buildings, wells etc. Breeds between February to April and after 95-100 days of gestation female give births to one offspring. Lactation last for 20 days and young can fly in 5-6 weeks. Male and female become mature, respectively, in 16-17 and 8.5-9.0 months of age. This rare Species is known to be found in Chattogram hill tracts and Khulna division including the Sunderbans. However, IUCN Bangladesh (2015) considered this as a Data Deficient Species.

5. Long-winged Tomb Bat (Taphozous longimanus, Emballonuridae):

Also known as Seath-tailed Bat. Bangla name is Lomba Dana Minar Chamchika or Thole Chamchika. Body length 7-9 cm, tail 2-3 cm and wingspan 40 cm. Female is larger than male. Fur is short, dense, and soft. Upper part is reddish-brown and under part is paler. Females are darker and juveniles are gray. Wings are narrow and dark brown. Males have well developed gular sacs. Ears stand straight. The Species is nocturnal and crepuscular. Except breeding season, male and female live in different unisexual colonies from 1-20 individuals together. Colonies of females are usually bigger. Diet is mainly insects, especially termites, cockroaches, beetles etc. Can live in different types of habitats and diurnal roosts includes caves, old buildings, wells, hollows in banyan and peepul trees etc. Female give births twice a year. Young are weaned after 4 weeks and become fully mature in 2 months. Previously the Species was only known to occur in St. Martin’s Island. However, IUCN Bangladesh (2015) considered this as a Data Deficient Species.

6. Greater False Vampire Bat (Megaderma lyra, Megadermatidae):

Also known as Indian False Vampire Bat or False Vampire Bat. Bangla name is Bhuyo Daini Badur, Daini Badur or Daini Chamchika. Body length 6.5-9.5 cm and weight 40-60 g. Upper part is dark slaty-gray and under part is whitish. Broad wings have grayish-black membranes. Large, elongated, and grayish black ears joined two-third of their length. Snout is naked with two oval-shaped nose-leaf. No tail. They are nocturnal and crepuscular. Colony size varies from a single individual to several hundreds. Diet includes insects, moths, frogs, rodents, small birds etc. Diurnal roosts include deserted houses, old buildings, caves, temples, forts, caves etc. Mating takes place between November and January. After 150-160 days of gestation females give birth to one or sometimes two pups from April to June. Males reach sexual maturity by 15 and female by 19 months of age. Lifespan is 5-20 years. They are common, widely distributed throughout the country and presumably has a large population.

7. Lesser False Vampire Bat (Megaderma spasma, Megadermatidae):

Also known as Lesser False Vampire or Common Asian Ghost Bat. Bangla name is Choto Bhuyo Daini Badur, Daini Badur or Daini Chamchika. Body length is 3.9 cm, wingspan is 30.0 cm and weight is 34 g. The fur is bluish-gray along the back and brown­ish-gray along the un­der­side. Ears are rounded, which are joined at the base. The short tail does not extend outside the membrane. They are nocturnal and crepuscular. Usually found in wet areas. At day time they roost in groups of 3-30 in­di­vid­u­als in hollow trees, caves, old build­ings, any other large, shel­tered struc­ture etc. Although, they are in­sec­ti­vorous; but can eat lizards, small rep­tiles, small ro­dents etc. Mat­ing sea­son is from No­vem­ber to Jan­u­ary. After 150-160 days of gestation usu­ally one, rarely two offspring are born be­tween April and June. This rare bat Species is recorded from forested areas of Khulna division including the Sunderbans. However, IUCN Bangladesh (2015) considered this as a Data Deficient Species.

8. Intermediate Leaf-nosed Bat (Hipposideros larvatus, Hipposideridae):

Also known as Intermediate Round-leaf Bat or Horsefield’s Leaf-nosed Bat that belongs to family. Bangla name is Majhari Pata Nak Chamchika. Body length 7.5 cm, tail 4.3 cm and weight 17.4-24.8 g. The diagnostic feature of this Species is the three lateral accessory leaflets on each side of the nose-leaf. Fur colour is dark gray-brown or reddish-brown, and the ears and nose-leaf are dark gray or brown. Ears are broad and roughly triangular in shape. They are nocturnal and crepuscular. Colony may contain several hundred bats, often shares their roosts with other bat Species. Mainly eat beetles, but can also take moths, butterflies, flies, mosquitoes, termites and other insects. Diurnal roosting place includes caves, abandoned mines, rock crevices, culverts, old buildings etc. Nothing is known about their breeding and lifespan. They are uncommon and found in mixed evergreen forests of Sylhet and Chattogram divisions; also recorded from Netrokona District.

9. Painted Woolly Bat (Kerivoula picta, Family: Vespertillionidae):

Also known as Painted Bat. Bangla Name is Rongin Chamchika or Komola-badami Chamchika. Body length is 3.1-5.7 cm, tail is 3.2-5.5 cm, wingspan is 18-30 cm and weight is 5 g. It is relatively a small bat. Body hairs are long, wooly and dense and colour is bright orange or scarlet with black wings and orange along the fingers. Naked ears are relatively large with rounded tips. Muzzle is very hairy with naked nostrils. Older males are brighter than females. They are nocturnal and crepuscular. Gen­er­ally fly in cir­cles close to the ground with a weak, flut­ter­ing flight. They are found in homestead, banana plantations etc. Roost singly, in pairs or in groups of only 2-6. Often roosts in tree hol­lows and trunks, fo­liage, huts, build­ings, even weaver or sunbird nests. Eat small insects. Although not much known about reproduction and lifespan, however, they have nuclear family units- that is, a mother, a father, and young. Breeds between June to August. Female give birth to a single offspring. This uncommon bat is distributed throughout the forested areas, especially Dhaka Division, of Bangladesh. However, IUCN Bangladesh (2015) considered this as a Data Deficient Species.

10. Coromendal Pipistrelle (Pipistrellus coromendra, Vespertillionidae):

Also known as Indian Pipistrelle or Little Indian Bat. Bangla name is Chamchika, Cham Badur or Khude Chamchika. Body length 3 cm, tail 3 cm, wingspan 19-22 cm and weight 9-13 g.  Coat colour is chocolate-brown at a glance. Wing membrane, face and ears are blackish-brown. Possess fairly dense and short fur. Tip of muzzle are naked. Ears are small, triangular shaped and have blunt tips. Female is larger than male. They are nocturnal and crepuscular. Diurnal roosting places includes crevices between logs, crevices in walls, under the ceilings and roofs of houses, under the bark of big banyan trees, dense vegetation, old buildings etc. Roost solitary or small family groups, sometimes up to 18 individuals. Diet includes flying insects and mosquitoes. Breed 3 times a year. Female usually give births to 2 pups in April, July to August and October to November. They are very common and widely distributed in different habitat type throughout the country.

11. Asiatic Yellow Bat (Scotophilus heathii, Family: Vespertillionidae):

Also known as Asiatic Greater House Bat, Greater Asiatic Yellow House Bat, Greater Asiatic Yellow Bat, Common Yellow Bat or Asiatic Greater Yellow House Bat. Bangla name is Boro Holdey Chamchika or Rongila Chamchika. Body is robust with a long tail. Body length 8-9 cm, tail is 5.9 cm, wingspan is 40 cm., and weight is 48-52 g. Adults are yellowish bronze-brown above and bright yellow to reddish below. Wing membrane is blackish brown. Fur is short and dense except on neck. Muzzle is blunt, naked, and dark. Young is dark grayish-brown. They are nocturnal and crepuscular. The Species is a low flyer and flies at a steady speed. They can live in a variety of habitat types, including urban areas. Roost singly or in colonies of up to 50 individuals. Diurnal roosts include crevices and cracks in old buildings, among the leaves and crowns of palms, in hollows of trees and among banana leaves etc. No information is available on their foods. Not much information is available on reproduction, breeding, and lifespan. However, female give births to 1-2 offspring in April to May after 115 days of gestation. They are uncommon and distributed throughout the forested areas of Sylhet and Chattogram division.

12. Dormer’s Bat (Scotozous dormer, Family: Vespertillionidae):

Also known as Dormer’s Pipistrelle. Bangla name is Dormarer Chamchika or Dormarer Badur. This medium-sized bat’s head-body length is 4.89 cm and tail is 3.53 cm. Upper part is gray-brown with some hair tips almost silver in colour. Under part is paler with all hair tips white or pale buffy-white. Ears, naked areas of face and membranes are uniform mid-brown. The Species is nocturnal and crepuscular. Flies with rapid wings beat, but not a fast flier. They live in dry forests, plantations, rural gardens, urban areas, near human habitations etc. Day time roosts in cracks, crevices, holes in old temples, old disused buildings, holes in large trees etc. Usually roosts in colonies of 2-24 individuals. They are insectivorous; eat beetles, moths, grasshoppers, crickets, winged termites etc. Not much information is available on reproduction. But breeds throughout the year. This Species has been categorized as Least Concern in the view of its wide distribution throughout the country.

Bats provide important ecological services worldwide and are among the most neglected mammals in Bangladesh. For instance, though the fruit bats cause occasional damage to fruits, however, they play major roles in plant pollination, seed dispersal, and forest regeneration, while insectivorous bats control harmful crop insects and serious disease vectors. Excessive exploitation of natural resources, alteration of habitats and cutting down of tall trees have depleted the bat populations in Bangladesh. Therefore, urgent measures should be taken to save the bats from fast decline in Bangladesh. Last remaining roosting trees of the flying fox needs to be saved from cutting by declaring these as national property. Bats in Bangladesh made international news in 2001 when the first outbreak of Nipah virus occurred. In other regions, bats are known to carry other zoonotic diseases such as Ebola, SARS, Hendra and MERS. Risks of bat-related disease outbreaks have increased due to habitat destruction and wildlife trade bringing bats into closer contact with human beings. To safeguard environmental and public health, increased research on bats is needed from ecological, conservation and medical standpoints. According to IUCN Bangladesh (2015) out of 35 Species of bats found in Bangladesh 6 are Near Extinct, 18 are Data Deficient and 11 are List Concern. Natural history and biology of most of the bat Species in Bangladesh is still unknown. Therefore, research should be done to unveil the biology and natural history of bats of Bangladesh. Even there are chances to discover some more new Species of bats in Bangladesh. On the other hand, proper knowledge about bats must be disseminated by the government, NGOs, biologist, and media for their survival and keep the nature balanced. There is also an urgent need for making the public aware about the beneficial aspects of all bats and removing the century-old misconceptions about bats.

References:

1. Bates, P.J.J. & D.L. Harrison (1997). Bats of the Indian Subcontinent. Harrison Zoological Museum, Kent, United Kingdom, xvi+258pp.
2. Corbet, G.B. & J.E. Hill (1992). The Mammals of the Indomalayan Region: A Systematic Review. Oxford University Press, Oxford, United Kingdom, 488pp.
3. Francis, C.M. (2008). A Guide to the Mammals of Southeast Asia. Princeton University Press, Princeton, New Jersey, 392pp.
4. Hasan, M.K., Khan, M.M.H. and Feeroz, M.M. (2014). Amphibians and Reptiles of Bangladesh- A Field Guide. Arannayk Foundation, Dhaka. 191 pp.
5. Islam, N (2013). A first for bat in Bangladesh. Bats, 31(1):13-14.
6. Khan, M.A.R. (2001). Status and distribution of bats in Bangladesh with notes on their ecology. Zoos’ Print Journal 16(5): 479–483.
7. Khan, M.A.R. (2015). Wildlife of Bangladesh: Checklist and Guide. Chayabithi, Dhaka. 568 pp.
8. Khan, M.M.H. (2008). Photographic Guide to the Wildlife of Bangladesh. Arannyak Foundation, Dhaka. 488pp.
9. Kruskop S.V. (2013). Bats of Vietnam: Checklist and an Identification Manual. Joint Russian-Vietnamese Science and Technological Tropical Centre, Zoological Museum of Moscow M.V. Lomonosov State University, Moscow, 316pp.
10. Racey, P.A. (2009). Reproductive assessment in bats, pp. 249–264. In: Kunz, T.H. & S. Parsons (eds.). Ecological and Behavioral Methods for the Study of Bats – 2nd Edition. Johns Hopkins University Press, Baltimore, 901pp.
11. Rahman, A.N.M.A. (2015). Wildlife of Bangladesh, Department of Film & Publication, Ministry of Information, Dhaka, Bangladesh.
12. Rahman, A.N.M.A. (2017). Bats: The most neglected mammals of Bangladesh. Bangladesh Quarterly, 37(4):55-
13. Simmons, N.B. (2005). Order Chiroptera, pp. 312–529. In: Wilson, D.E. & D.M. Reeder (eds.). Mammal Species of the World: A Taxonomic and Geographic Reference – 3rd Edition. 1. Johns Hopkins University Press, Baltimore, 1–743pp.
14. Srinivasulu, C. & B. Srinivasulu (2005). A review of chiropteran diversity of Bangladesh. Bat Net – CCINSA Newsletter 6(2): 5–11.

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রুবাইয়াত-ই-তাবাসসুম

স্নাতকোত্তর শিক্ষার্থী
প্রাণরসায়ন ও অনুপ্রাণবিজ্ঞান বিভাগ
ঢাকা বিশ্ববিদ্যালয়

কোন রোগ কতটা ভয়ানক, তার ভয়াবহতা যাচাই করার অন্যতম জনপ্রিয় একটি উপায় হল রোগবাহী জীবাণুর বেসিক রিপ্রোডাকশন নাম্বার নির্ণয় করা। একজন রোগাক্রান্ত রোগী তার মাধ্যমে আরো কতজনকে আক্রান্ত করতে পারে, সেই সংখ্যাই হল বেসিক রিপ্রোডাকশন নাম্বার, অথবা R₀ (আর-নট)। জিকা ভাইরাসের ক্ষেত্রে এ সংখ্যাটা ৬.৬ পর্যন্ত হতে পারে, হামের ক্ষেত্রে ১২-১৮, মৌসুমী জ্বরের ক্ষেত্রে ১ এর কিছুটা বেশি, আর কোভিড ১৯ এর ক্ষেত্রে ২ থেকে ২.৫। সাধারণ জ্বর আর কোভিড ১৯ এর ক্ষেত্রে আর-নট এর তফাৎটা খুব বেশি না, আর এ দুয়ের লক্ষণগুলোও কম বেশি এক ই হওয়ায় মনে হতে পারে, দুয়ের মধ্যে ভয়াবহতায় পার্থক্য নেই।

যদি আর-নট নাম্বারের দিক তাকাই, ১০রাউন্ড যাবার পর একজন সাধারণ জ্বরে আক্রান্ত রোগী সর্বোচ্চ ৫৬ জনকে আক্রান্ত করতে পারে। আর-নট কে ২ ধরে এক ই মডেল কোভিড ১৯ এর ক্ষেত্রে দাঁড় করালে, ১০ রাউন্ড পরে একজনমাত্র রোগী থেকে আক্রান্ত রোগীর সংখ্যা দাঁড়াচ্ছে ২০৪৭!

কোভিড ১৯ এ আক্রান্ত হবার পর ৫- ১৪ দিন পর্যন্ত সময় লেগে যেতে পারে লক্ষণ প্রকাশ হতে। লক্ষন প্রকাশ না হবার আগ পর্যন্ত এই যে সুপ্তাবস্থা, রোগাক্রান্ত মানুষ তখন কাজ করে নীরব বাহক হিসেবে। অর্থাৎ, তার অজান্তেই সে রোগ ছড়িয়ে বেড়াচ্ছে!

মৌসুমি জ্বরের ক্ষেত্রে দেখা যায়, বেশিরভাগ মানুষ এর বিরুদ্ধে ইতোমধ্যে প্রতিরক্ষা ব্যবস্থা তৈরি করে ফেলেছে শরীরে, কারণ ভাইরাসটা তাদেরকে এর আগেও আক্রান্ত করেছে। তখন জ্বর তাদেরই হয়, যারা প্রতিরক্ষা ব্যবস্থা তৈরি করেনি শরীরে ঐ নির্দিষ্ট ভাইরাসের বিরুদ্ধে। যেহেতু করোনা ভাইরাস একদম ই নতুন, কারও শরীরেই স্বাভাবিকভাবে এর বিরুদ্ধে প্রতিরক্ষা ব্যবস্থা নেই, তাই বলা যায়, পৃথিবীর প্রায় সব মানুষের ই এর দ্বারা আক্রান্ত হবার আশংকা আছে।

কোভিড ১৯ এ পৃথিবীজুড়ে এ পর্যন্ত মাত্র ৩ মাসে আক্রান্ত হয়েছে ২১,৭২,০৩১। এর মধ্যে সুস্থ হয়েছেন ৫,৫৪,২৩২ জন, মৃত্যু হয়েছে ১,৪৬,২০১ জনের ! আমেরিকাতে আক্রান্তের সংখ্যা এ পর্যন্ত সর্বাধিক, এবং সুস্থ হয়ে ফিরে আসার সংখ্যার ভিত্তিতে জার্মানি সবচেয়ে এগিয়ে। জার্মানির মত এরকম আরো কটা দেশের সাফল্যের পিছনে যে ব্যাপারটা সবচেয়ে বেশি ভূমিকা রেখেছে, তা হল, যত বেশি টেস্ট, তত কম ভয়াবহতা।

এখানে বিশেষত উল্লেখ করতে হয়, দক্ষিণ কোরিয়ার কথা। অন্য দেশের মত শুরুতে তাদের দেশে আক্রান্তের সংখ্যা বেশ বাড়তে থাকলেও ক্রমশই তারা তা কমিয়ে আনতে সক্ষম হয় ২০১৫ সালে অর্জিত তাদের অভিজ্ঞতা কাজে লাগিয়ে। সে বছর এক প্রকার করোনাভাইরাস মার্স (মিডল ইস্ট রেসপিরেটোরি সিন্ড্রোম)  নামে এক রোগের প্রাদুর্ভাব ঘটিয়েছিল। ১০৮৬ জন দক্ষিণ কোরীয় মার্স ইনফেকশনের স্বীকার হয়েছিলেন তখন। ২০১৫ সালেই এই ভাইরাসের প্রাদুর্ভাব শেষ হলেও সরকারিভাবে পরিকল্পনা তারা চালিয়ে গিয়েছিলেন, যাতে এরকম ভাইরাস আবার ফিরে এলে ক্ষয়ক্ষতির পরিমাণ কম হয়। হয়েছেও তাই, ফেব্রুয়ারির মধ্যেই তারা হাজার হাজার টেস্টকিট বানিয়ে ফেললেন। তারা ডায়াগনোস্টিক টেস্টের প্রয়োজনীয়তা আগেই উপলব্ধি করেছিলেন, প্রস্তুত ছিলেন ক্ষয়ক্ষতির জন্যে, তাই ক্ষতির মাশুল ও তাদের দেওয়ার কথা ছিল তুলনামূলকভাবে অনেক কম। কিন্তু ঝামেলা বাধাল কোভিড ১৯ এ আক্রান্ত দক্ষিণ কোরিয়ার ৩১ নং রোগী, যাকে মিডিয়ায় Patient 31 বলে উল্লেখ করা হয়। তিনি একাই লোকসমাগমে এসে বহু সুস্থ লোককে আক্রান্ত করার বাহক হিসেবে কাজ করেছিলেন (পূর্বে উল্লেখিত আর-নট এর ব্যাখ্যাতেই বলা হয়েছে)।  এরপরে কর্তৃপক্ষ Contact Tracing এর মাধ্যমে খুঁজে বের করেন কারা পেশেন্ট ৩১ এর সান্নিধ্যে এসেছিলেন। দেখা গেল প্রায় ৯০০০ লোক প্রত্যক্ষ অথবা পরোক্ষভাবে এর শিকার হয়েছেন। তাদের সবাইকে টেস্ট করে আইসোলেশনে পাঠানো হয়। এরপর সমগ্র দক্ষিণ কোরিয়াজুড়ে প্রায় বিনামূল্যে এর জনগণকে টেস্ট করতে সরকারি ও বেসরকারি টেস্টিং সেন্টার ঝাঁপিয়ে পড়ে । প্রায় ৬০০র ও বেশি জায়গায় দিনে ২০,০০০ পর্যন্ত মানুষকে টেস্ট করা হয়েছে।যাকেই তারা কোভিড ১৯ পজিটিভ পেয়েছে, সাথে সাথে তার সান্নিধ্যে যারা এসেছে (কন্ট্যাক্ট ট্রেসিং), তাদের সবাইকে আইসোলেশনে পাঠানো হয়েছে।

সবচেয়ে কার্যকরী যে পদক্ষেপটা তারা নিয়েছে, তা হল, আক্রান্ত ব্যক্তি কে কোথায় যাচ্ছে, সব তথ্যই তারা ডেটাবেসে হালনাগাদ করে জনগণের জন্যেও উন্মুক্ত করেছে এবং যখন ই অন্য কেউ সে লোকেশনের ধারে কাছে যাচ্ছে, জিপিএস এর মাধ্যমে ট্র্যাক করে তাদের মোবাইলে ইমার্জেন্সি এলার্ট পাঠানো হয়েছে।এর মাধ্যমে মানুষ জানতে পারল সে কোনভাবে কোভিড ১৯ এ আক্রান্ত রোগীর পথ দিয়ে গেছে কিনা, আর গেলেও সে সাথে সাথে টেস্ট সেন্টারে গিয়ে টেস্ট করে জেনে নিচ্ছে সে আক্রান্ত হল কিনা। ফলে আমাদের মত বিশাল সময়ব্যাপী লকডাউনেও তাদের পড়তে হয়নি।

পৃথিবীব্যাপী ছড়িয়ে পড়া এ ভাইরাসের বিস্তার রোধে গবেষকরাও বসে নেই। বেশ কিছু ভ্যাক্সিন এর ক্লিনিক্যাল ট্রায়াল ইতোমধ্যে শুরু হয়ে গেছে। তেমন ই একটি হল mRNA-1273। এটি করোনাভাইরাসের স্পাইক প্রোটিনকে কোড করে। অন্য সব ভ্যাক্সিনের মতই, এটি প্রতিরক্ষাকারী, রোগদানকারী নয়। কোন ওষুধকে পার্শ্বপ্রতিক্রিয়ামুক্ত এবং রোগ দমনে কার্যকরী প্রমাণ করতে হলে একে ৪টি ধাপ অতিক্রম করতে হয়। এই mRNA-1273 আপাতত মাত্র ধাপ ১ এ আছে। মার্চের ৩ তারিখে প্রথম ৪৫জন সুস্থ ও প্রাপ্তবয়স্ক ব্যক্তির (পুরুষ এবং গর্ভবতী নয় এমন নারী) ওপর এ ভ্যাক্সিন প্রয়োগ করা হয়। আশা করা যাচ্ছে, ২০২১ এর জুন মাস পর্যন্ত লেগে যাবে সব ধরণের যাচাই বাছাই প্রক্রিয়া শেষ করতে।

চারিদিকে হৈচৈ ফেলে দেয়া যে এন্টিভাইরাল ওষুধটার কথা এখন বলব, নাম Remdesivir। এটি ইতিমধ্যেই ক্লিনিক্যাল ট্রায়ালের ধাপ ৩ এ সাফল্যের সাথে উত্তীর্ণ হয়ে গেছে। ২১ শে ফেব্রুয়ারি থেকে শুরু হওয়া এর ক্লিনিক্যাল ট্রায়ালে ৪৪০জনে এটি প্রয়োগ করা হয়েছে। এর ট্রায়াল ডিজাইন টা আগেরটা থেকে কিছুটা ভিন্ন। যারা নিশ্চিতভাবেই জানে যে তারা কোভিড ১৯ এ আক্রান্ত, শুধু তাদের ক্ষেত্রেই এটি প্রয়োগ করা হবে।  এটি ডাবল ব্লাইন্ড, অর্থাৎ যাকে দেয়া হচ্ছে এবং যে মনিটর করছে, কেউ ই জানেনা যা ইনজেকশনের মাধ্যমে রক্তবাহী শিরায় ওষুধ টা কাকে দেয়া হয়েছে! কারণ, এখানে ট্রায়ালে ২ গ্রুপে ভাগ করে ফেলা হয়। এক গ্রুপ হল কন্ট্রোল গ্রুপ, যাদেরকে Remdesivir এর মতই দেখতে হুবুহু “কিছু একটা” (সাধারণত নিরপেক্ষ কিছুই দেয়া হয়।প্রতিটা ওষুধে তাদের সক্রিয় উপাদানের সাথে অনেক নিষ্ক্রিয় উপাদান ও যোগ করে দেয়া হয় ওষুধের স্থায়িত্ব বাড়ানোর জন্য। সেরকম ই নিষ্ক্রিয় উপাদানের সমন্বয়ে, কিন্তু Remdesivir এর সক্রিয় উপাদানকে বাদ দিয়ে ওষুধের অনুরূপ ফর্মুলা ড্রাগ বানিয়ে কন্ট্রোল গ্রুপকে দেয়া হয়।একে প্লেসিবো ইফেক্ট বলে। ) দেয়া হয়, কিন্তু আদতে সেটা Remdesivir নয়! শুধু বাহ্যিকভাবে দেখতে তারা অনুরূপ। আরেক গ্রুপ থাকে টেস্ট গ্রুপ, যাদের আসলেই Remdesivir দেয়া হচ্ছে। ফলাফলকে দুই ভাগে ভাগ করা হয়ঃ মুখ্য ফলাফল ও গৌণ ফলাফল। মুখ্য ফলাফল এর অন্তর্ভুক্ত হল Remdesivir দেয়ার ১৫ দিনের মধ্যে রোগী মৃত্যুবরণ করল কিনা, হাসপাতালে গেল কিনা, সুস্থ হল কিনা। গৌণ ফলাফল হল আক্রান্ত হবার দিন থেকে ২৯ দিনের মধ্যে ALT, AST, Creatinine, Glucose, Hemoglobin ইত্যাদির পরিবর্তন পরিমাপ করা। এই সব যদি ব্যাটে বলে মিলে যায়, তাহলেও এই পরীক্ষা নিরীক্ষা শেষ হতে আশা করা যাচ্ছে ২০২৩ লেগে যাবে, অন্তত ওয়েবসাইট তাই বলছে।

আরেকটি এন্টিভাইরাল ওষুধ যা ধাপ ২ উত্তীর্ণ হয়েছে, তার নাম Deferoxamine।এটিও আগেরটির মতই ডাবল ব্লাইন্ডেড ট্রিট্মেন্ট। এ ওষুধের মূল উপাদান হল ডেসফেরাল, যা মূলত শরীরের লৌহ উপাদানকে আটকে ফেলে, যাকে আমরা বলি chelate করে ফেলা। ৩ থেকে ৯৯ বছর বয়সী কোভিড ১৯ পজিটিভ রোগীদের ক্ষেত্রে এটি প্রয়োগ করা হচ্ছে, অবশ্যই তাদের অনুমতি সাপেক্ষে। এটিও আগেরটির মতই রক্তবাহী শিরায় ইনজেকশনের মাধ্যমে দেয়া হয়। এর ক্লিনিক্যাল ট্রায়াল শেষ হবার সম্ভাব্য সময় ২০২১ এর মার্চ! বেশ দেরি।

যেহেতু এখনো কিছুই নিশ্চিতভাবে আবিষ্কৃত হয়নি, ততদিন পর্যন্ত লকডাউনে বসে আসুন নিজেরা বাঁচি , পৃথিবীটাকে বাঁচাই ! আর যদি দক্ষিন কোরিয়ার মতই এত কড়াকড়ি লকডাউনে থাকতে না চান, তবে তাদের মতই aggressive testing method এ যেতে হবে। সরকারের সদিচ্ছা আর কার্যকরী পদক্ষেপ, সাথে অবশ্যই জনগণের চেষ্টাই নির্ধারণ করবে মৃত্যুর মিছিলে আরো কত প্রাণ ঝরে যাবে, নাকি আবারও প্রাণের বাংলাদেশ দিনের আলো ফোটার সাথে সাথে হাসবে আগের মত হাজারো মুখরিত প্রাণ বুকে ধরে। সেই সুদিন আসুক শিগগির ই!

তথ্যসূত্রঃ

১।  COVID-19 Dashboard by the Center for Systems Science and Engineering (CSSE) at Johns Hopkins University. (Last updated: April 17, 2020 5.38 p.m). Retrieved from  https://www.arcgis.com/apps/opsdashboard/index.html#/bda7594740fd40299423467b48e9ecf6

২। Vox. (April 1, 2020). “Coronavirus is not the flu. It’s worse”. Retrieved from https://www.youtube.com/watch?v=FVIGhz3uwuQ&t=14s

৩। Vox. (April 10, 2020). “The big lesson from South Korea’s coronavirus response”. Retrieved from https://www.youtube.com/watch?v=BE-cA4UK07c&t=6s

৪। National Institute of Allergy and Infectious Diseases (NIAID). (April 13, 2020). “Safety and Immunogenicity Study of 2019-nCoV Vaccine (mRNA-1273) for Prophylaxis SARS CoV-2 Infection (COVID-19)”. NIH. Retrieved from https://clinicaltrials.gov/ct2/show/NCT04283461

৫। National Institute of Allergy and Infectious Diseases (NIAID). (April 6, 2020). “Adaptive COVID-19 Treatment Trial (ACTT)”. NIH. Retrieved from https://clinicaltrials.gov/ct2/show/NCT04280705

৬। Dr. Yadollah Shakiba, Kermanshah University of Medical Science. (April 6, 2020). “Application of Desferal to Treat COVID-19”. NIH. Retrieved from https://clinicaltrials.gov/ct2/show/NCT04333550?cond=COVID-19&draw=2&rank=1

The post কোভিড ১৯ ও আমাদের হাতিয়ারঃ কতটা প্রস্তুত পৃথিবী? appeared first on NSSB.

পদ্ম ফুল

– আজহারুল ইসলাম।

আফ্রিকার গহীন অরন্যে এক ধরনের উদ্ভিদ বাস করে সাধারণ উদ্ভিদের মতই এদের বাহিরের চেহারাটা বেশ নিরীহ। এরা সর্পিল ডালাপালা মেলে উঁৎ পেতে বসে থাকে শিকারের আশায়,হঠাৎ ভুল করে কোন জীব জন্তু বা মানুষ এদের নাগালের মধ্যে গিয়ে পড়লেই সরু লিকলিকে ডালপালা গুলি প্রসারিত হয়ে অক্টোপাসের মত তাকে আস্টে পিষ্টে বেঁধে ফেলে। তারপর বিষাক্ত কাঁটার ঘায়ে শিকারকে আচ্ছন্ন করে ধীরে ধীরে তার রক্ত মাংশ হজম করতে থাকে। কয়েকদিন পর এদের বাহুপাশ শিথীল হলে দেখা যায় শিকারের হাড়গুলো শুধু অবশিষ্ট আছে। ঘোড়াসহ একজন ঘোড়সোয়ার কেও এরা এইভাবে হজম করার ক্ষমতা রাখে। ছেলেবেলায় দাদির মুখে আফ্রিকার জঙ্গলে প্রাপ্ত উদ্ভিদ সম্পর্কে এই রোমাঞ্চকর ও চিত্তাকর্ষক গল্প শুনে মনে মনে শুধু ভাবতাম কবে বড় হবো আর আফ্রিকার জঙ্গলে অবস্থিত মানুষ খেকো উদ্ভিদ সরেজমিনে পরিদর্শন করতে যাবো। কিন্তু বড় হয়ে যখন জেনেছি মানুষ খেকো গাছের সঙ্গে বাস্তবতার খুব অল্পই সম্পর্ক আছে। তখন এই গল্পগুলিকে একান্তভাবেই মানুষের চিন্তাশক্তি বা দুশ্চিন্তাশক্তির ক্রমবিকাশ বলেই মনে হয়েছে।

তবে কিছু কার্নিভোরাস উদ্ভিদ আছে যারা ছোট ছোট পোকামাকড়, ব্যাঙ ইত্যাদি প্রাণীকে ফাঁদে আটক করে তাদের খাদ্য গ্রহন করে। আমরা জানি প্রায় সকল উদ্ভিদেরই পুষ্টি গ্রহণ পদ্ধতি একই রকম হয়ে থাকে। অর্থাৎ এরা মাটিস্থ পানি ও খনিজ লবন এবং বায়ুর কার্বন ডাইঅক্সাইডকে(Co2) কাজে লাগিয়ে খাবার প্রস্তুত করে। কিন্তু কার্নিভোরাস উদ্ভিদ গুলো পুষ্টির জন্য প্রাণীর উপর নির্ভরশীল হয় অর্থাৎ সহজে বলতে গেলে এরা প্রাণীদের ভক্ষণ করে। কথাটা অবাস্তব মনে হলেও পৃথিবীতে অবস্থিত এমন উদ্ভিদ কেই মাংসাশী উদ্ভিদ (Carnivorous plants) বলে এবং এদের মধ্যে ভেনাস ফ্লাইট্র্যাপ (Venus Fly trap, Dionaea Muscipula) একটি অন্যতম উদ্ভিদ। এই উদ্ভিদকে পতঙ্গভূক (Insectivorous Plants) উদ্ভিদও বলা হয়।

পাতা সহ পদ্ম পুকর

পৃথিবীতে উদ্ভিদই মনে হয় যেন আদর্শ অহিংস জীবন যাপন করে থাকে।এদের আক্রমণ করলে কোন প্রতি-আক্রমণ করে না এদের বংশ নির্বংশ করার পরিকল্পনা করলেও কোন প্রতিবাদ করে না। উদ্ভিদের অহিংস নীতির কারনেই হয়ত এরা বেঁচে থাকে শত শত বছর। জীব সৃষ্টির সূচনা লগ্ন থেকেই জলে স্থলে অন্তরীক্ষে উদ্ভিদের আধিপত্য অব্যাহত আছে। প্রাণশক্তিতে ভরপুর উদ্ভিদ নিজেদের টিকিয়ে রাখার জন্য কত রকম কৌশল অবলম্বন করে তা নিয়ে বিজ্ঞানিরা অক্লান্ত পরিশ্রম করেও সবকিছু উন্মুক্ত করতে পারেননি। ৪০-৫০ হাজার বছর পর্যন্ত ঘাপটি মেরে পড়ে থাকা পদ্মের বীজ অনুকুল পরিবেশ পেলে অঙ্কুরোদগম হয়। এমন কথা শুনলে অনেকের ধারনা হবে এটাও আফ্রিকার মানুষ খেকো উদ্ভিদের মত শুধুই রোমাঞ্চকর ও চিত্তাকর্ষক গল্প।

পদ্মের বর্ণ, পাপড়ি,পাতা সবকিছুই সুন্দর,তাই আমরা যাকিছু সুন্দর তাকে পদ্মের সাথে তুলনা করি। সুলক্ষণা সুন্দরী নারীকে অনেকে পদ্মিনী বলে আখ্যায়িত করে থাকেন। ভারতে কৃতিত্বপূর্ণ কাজের জন্য পদ্মভূষণ উপাধি দেয়া হয়। শুনেছি পৃথিবী সৃষ্টির সূচনালগ্নে পদ্মের সৃষ্টি হয়েছিলো। বাংলাদেশের খালে বিলে পদ্মের বাসস্থান দেখা যায়। কবি সাহিত্যিকরা পদ্মের রূপ দেখে এদের সৌন্দর্য বর্ননা করতে সামান্য কৃপণতা করেননি। তারা বিমুগ্ধ চিত্তে লক্ষ্য করেছিলেন কোমল চাঁদের আলোর স্পর্শে পদ্ম দলমেলে কেমন হেসে উঠে, আবার প্রখর রোদের স্পর্শে কেমন কুণ্ঠিত হয়ে দল গুটিয়ে নেয়। পদ্ম একান্তভাবে ভারতবর্ষের উদ্ভিদ হলেও চীন জাপান অস্ট্রেলিয়া ও আমেরিকায় এদের পাওয়া যায় তবে ইউরোপে এদের আধিপত্য খুবই সীমিত।

কিছুদিন আগে বিজ্ঞানী মহলে পদ্মবীজের আয়ুষ্কাল নিয়ে হৈ-চৈ পড়ে গিয়েছিলো। জাপানী বিজ্ঞানীরা হঠাৎ দাবি করে বসলেন তাঁরা দেখেছেন ১০-২০ হাজার বছরের পুরানো পদ্মের বীজ মাটির নিচে চাপা পড়ে থাকা অবস্থা থেকে উপযুক্ত পরিবেশে নিয়ে আসলে অঙ্কুরিত হতে পারে। কিন্তু সেদিন তাদের কথায় কেউ কর্ণপাত করেনি। বরং অনেকের কাছে তারা উপহাসের পাত্র হয়েছিলেন। সম্প্রতি চীনে মাঞ্চুরিয়া হ্রদের তলদেশ থেকে ৪০-৫০ হাজার বছর পুরানো কিছু পদ্ম বীজ পাওয়া যায়,বীজের খোসাগুলো ফসিলে পরিনত হয়ে গিয়েছিলো। এই ফসিলের বৈশিষ্ট্য ও মাটির তলায় অবস্থানের খুঁটিনাটি বিবরণ পরীক্ষা নিরীক্ষা করে বিশেষজ্ঞরা এদের প্রাক-ঐতিহাসিক সম্পর্কে নিশ্চিত হয়েছেন।

পদ্মের বীজ

এরপর কয়েকজন বিজ্ঞানীর তত্ত্বাবধানে এই বীজগুলো ওয়াশিংটন ন্যাশানাল পার্কে এবং ক্যালিফোর্নিয়া বোটানিক্যাল গার্ডেনে অঙ্কুরিত করার চেষ্টা করা হয় এবং তাঁদের সে প্রচেষ্টা সফল হয়েছে। প্রায় ৪০-৫০ হাজার বছরের দীর্ঘ নিদ্রা ভঙ্গ করে অবশেষে পদ্মের ভ্রুণ আবার বীজ থেকে বেরিয়ে বিকশিত কিশলয়ে সূর্যের আলো পান করছে। বিজ্ঞানীদের গবেষনায় এটাও প্রমানিত হয়েছে এই সুদীর্ঘ কাল ধরে বীজের মধ্যে ভ্রুণ সম্পুর্ন জীবিত অবস্থায় ছিলো নইলে এই অঙ্কুরোদগম সম্ভব ছিলো না। এই বেঁচে থাকার জন্য তাকে প্রতি মুহুর্তে শ্বাস-প্রশ্বাস নিতে হয়েছে আর যথেষ্ট পরিমান বীজপত্রের জন্য খাদ্য সঞ্চয় করতে হয়েছে। কিন্তু কোন বিশেষ শক্তির প্রভাবে বা রাসায়নিক ক্রিয়ার প্রভাবে পদ্ম বীজ প্রায় ৫০ হাজার বছরের সুদীর্ঘ জীবন লাভ করলো সেটা জীব বিজ্ঞানীদের কাছে এক নতুন চ্যালেঞ্জ হিসেবে দেখা দিয়েছে। বিজ্ঞানীরা তাঁদের গবেষণা কালে দেখেছিলেন পদ্ম বীজের খোসাটি পাথরের মত শক্ত হয়ে গিয়েছিলো এবং বাহির থেকে পানি ও বাতাস প্রবেশ সম্পুর্ন বন্ধ হয়ে গিয়েছিলো। তাহলে কিভাবে এই বীজ এত বছর বেঁচে ছিলো এই নিয়ে বিজ্ঞানী মহলে আলোড়ন সৃষ্টি করেছে, হয়ত একদিন এই অন্ধকার উন্মোচিত হবে সাধারন মানুষ জানতে পারবে এই মৃত্যুঞ্জয়ী উদ্ভিদ সম্পর্কে।

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