The unique mangrove eco-system of the Sundarbans must be saved from any further degradation.

Bangladesh faces a number of environmental problems due to its geographical location and setting, high density of population, poor socio-economic development, inefficient resource management and institutional framework. A study on Bangladesh state of environmental has been able to identify five environmental issues on a priority basis as points of national concern. On the basis of the methodology used by the Organization for Economic Cooperation and Development which is termed Pressure-State-Impact-Response (P-S-I-R) framework analysis, these key environmental issues have been critically analyzed. Some appropriate and necessary responses with regards to policies/programmes will be proposed so as to alleviate further environmental deterioration, thereby enhancing and modifying the environmental conditions positively, as well as improving the environmental quality of life in Bangladesh.
In identifying the basic environmental issues of Bangladesh, two major criteria were kept in mind. First, the severity of the present environmental degradation, and the anticipated future trends that have critical implications for attaining sustainable development and the quality of life; Second, the priority, ability and willingness of the country to minimize the degradation processes, and to take protection measures against them. With these in mind, five environmental issues have been selected to be evaluated using the P-S-I-R framework. The identified key issues include land degradation (with impact on ecology and quality of life), water pollution and scarcity (impact on ecology and quality of life), air pollution (impact on environment and health), biodiversity (impact on ecology, development and quality of life) and natural disaster (impact on environment, development and quality of life).
The P-S-I-R framework adopted in this analysis can be defined as follows: Pressures are termed as any fundamental, natural and manmade forces that influence the state of the environment. State refers to the prevailing conditions of the environment resulting from the pressures, which might lead to various impacts that can influence human health and well being, as well as the socio-economic conditions of the society, with an adverse effect on the ecological balance. Finally, response defines an attempt to mitigate the impacts, through formulation, enactments, and enforcement of necessary laws and regulations by the government, through its relevant agencies.
The five key environmental issues:
Land degradation
The rapid population growth coupled with poverty, lack of proper land use and other driving forces, have led to over-exploitation of natural resources like land in Bangladesh.
Land degradation varies according to regions, seasons and years due to the diverse nature of the driving forces and their subsequent causes. Land degradation in the flood plains is chiefly attributable to improper use of fertilizer and pesticides. In the coastal areas it is partly due to the nature of shrimp culture which requires letting in saline water into empoldered shrimp beds. Erosion of topsoils in the hilly districts has increased. Excessive irrigation of agricultural lands may also contribute to soil degradation. For example: it was observed in Chandpur irrigation project area that deficiency of zinc content in the soil had occurred through leaching. The deficiency was corrected simply by injecting zinc into the soil of the affected areas. Soil resources development institute (SRDI) has found that nitrogen deficiency is a common phenomenon in the country.
Water pollution and scarcity
The seasonal/regional availability and the quality of surface and ground water, highly influence the environmental as well as the economic growth and development of Bangladesh. Spatial and seasonal availability of surface and groundwater is highly responsive to the monsoon climate and physiography of the country. Upstream withdrawal for consumptive and non-consumptive uses also influences availability. The surface water quality is affected by untreated industrial effluents, municipal waste water and run off from the surface of the agricultural lands treated with pesticides and chemical fertilizers. Pollution problems in the rivers close to the industrial areas are exceedingly high. For example: The dissolved oxygen (DO) level in the Buriganga has been found to be very low, and hence toxic. The Sitalakhya, Turag and Balu are also highly polluted.
The water quality in Dhaka is so poor that the Environment Department of Bangladesh in a report said that “the water from surrounding rivers can no longer be considered as a supply source for human consumption. The aquatic environment for living organisms can be affected and bioaccumulation of harmful substances in the water-dependent food chain can occur. Excessive abstraction under pressures of increasingly larger population may further lower the ground water table and expose certain areas to serious scarcity and even land subsidence". Furthermore, the level of arsenic contents in the ground water is of major concern in Bangladesh.
Air pollution
In urban areas particularly in Dhaka and Chittagong the air quality has deteriorated. Two major sources of air pollution are vehicular emissions and industrial emissions. Emissions include odour, smoke, carbon monoxide, lead, un-burn carbon, nitrogen oxides and sulphur dioxide. A study on the presence of the suspended air particulate mass (APM) revealed that the concentration of APM in these two cities exceeds the threshold limits set by the Department of Environment. Department of Environment Report. Scientific Studies say that the density of lead in the air of Dhaka city in the dry season reaches 463 nanograms (one nanogram is one billionth of a gram) per cubic metre, the highest in the world. The lead concentration in the polluted air of Mexico City is 383 nanograms and Mumbai, it is 360 nanograms per cubic metre .
Recently, a number of measures have been put in place by Bangladesh government to control air pollution in the major urban centres. Some of these measures include; banning the use of two stroke engine vehicles, introduction and promotion of increased use of compressed natural gas (CNG) in vehicles in place of gasoline and the supply of only unleaded petrol since the leaded gasoline is one of the major air pollutants.
Biodiversity
Bio diversity in Bangladesh is significant. Rivers and inland water bodies support over 200 indigenous fish species and 150 species of birds. The marine water bodies harbour about 442 species of fish and 36 species of shrimps as well as significant number of crabs and turtles. The Sundarbans, one of the largest mangrove forests in the world, supports 300 species of plants, 400 species of fish and over 200 species of birds. It also serves as the feeding area of migratory birds during winter.
However like other sectors of Bangladesh ecology, the diverse biological resources are also threatened by human intervention through destruction and degradation of land, denuded forest and aquatic habitats. The threat is most visible in the fisheries and forestry sectors. Forest areas already small as a proportion of the total land area, is being depleted by the combined pressure from timber extraction, encroachment by expanded agricultural activities and by the land grabbers. The forest area like Madhupur, which used to be the home of many species of flora and fauna, has thinned out significantly in recent years.
Shrimp culture, owing to the method, has an adverse effect on soil condition, vegetation and crop production in the area. These are mainly due to intrusion of saline water into the shrimp beds and deposition of suspended silt that comes along with the saline water. Overfishing under conditions of population pressures has depleted the fish resources. Despite the presence of a law prohibiting the catch of fish below certain specified size, large quantities of Hilsa fry (Jhatka) are caught every year and find their way into small markets.
Bangladesh is a signatory to the Rio convention on bio-diversity and as such is bound by the international guidelines for conservation of plants and animal lives. A focus on biodiversity has been emphasized on forest and environment. There is a great potential in Bangladesh for biodiversity based sustainable development. In line with this, the Bangladesh National Biodiversity Strategy and Action Plan is under preparation as a part of the World Convention on Biological Diversity. In spite of all these, there is need to formulate and apply a wise and sustainable yield and harvest methodology as well as management plan that will be applied on the field, so that these biological resources are not over-exploited.
Natural disasters
Bangladesh is widely known as a land of natural disasters. On average, there are 6.14 natural disasters per year. Quick onset disasters are pretty regular. In 2007, there was a landslide in Chittagong, which killed around 150 people, two cyclones that made land fall, a tornado in the south-west, and many small earthquakes. Slow onset-events like river flooding, compliment the quick disasters. Bangladesh has not the resources to cope with these problems, and as such many people die than would in other places. Thus, the situation necessitates huge resource requirements for disaster management, including mitigation, recovery and preparedness. A timely and accurate alert system regarding impending disasters will help reduce the loss of life and property.
Conclusion
The status of the five key environmental issues in Bangladesh shows that the environmental condition of the resource base is degrading, despite several policy measures undertaken by the different branches of the government. Rapid population growth, improper use of land, poor resource management and uncontrolled discharge of pollutants from industries and vehicles are major causes of deterioration. Main underlying reasons includes lack of institutional capabilities, untrained human resources, lack of awareness, low community participation in resource management and a paucity of research for enabling policy makers to take proper environmental decisions. Addressing these deficiencies only will enable these countries most especially Bangladesh in its progress towards attaining sustainable environment and development.
The writes are, respectively, a Visiting Professor from Bangladesh and a Master's Student at the University of Ghent, Belgium. e-mail; [email protected]