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Heavy metal pollution was reported in commercially valuable freshwater edible fish in the Buriganga River, Bangladesh. The concentrations of As, Pb, Cd, Cr, Zn, and Cu were investigated in the muscle, gill, stomach, intestine, and liver of Heteropneustes fossilis caught at three stations to assess the degree of fish pollution by heavy metals. Significant differences in concentrations of analyzed elements were observed among different tissues, but not among the stations. The ranges of the measured concentrations (μg/g dry weight) in the tissues of H. fossilis were as follows: arsenic concentration was (0.2-0.4), (0.82-0.90), (3.29-3.99), (2.20-2.80), and (2.41-2.90), that of lead was (1.79-2.20), (4.95-6.55), (10.36-13.38), (5.74-9.70), and (18.20-18.79), that of cadmium was (0.3-0.4), (2.87-4.27), (1.03-1.63), (1.55-4.59), and (2.25-5.50), that of chromium was (1.40-1.70), (3.52-3.72), (2.28-5.29), (2.77-3.79), and (4.25-8.65), that of zinc was (24.47-28.82), (16.82-18.80), (20.22-22.20), (22.86-26.68), and (60.82-67.80), and that of copper was (7.80-8.50), (6.22-6.81), (38.21-44.25), (17.07-21.03), and (43.24-47.30) in the muscle, gill, stomach, intestine, and liver, respectively. This research showed that the liver appeared to be the main heavy metal storage tissue, while the muscle had the lowest levels of analyzed metals. The concentrations of metal in the muscles not exceeded the acceptable levels for a food source for human consumption.

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A field experiment was conducted at the central research farm of Bangladesh Agricultural Research Institute, Gazipur for two consecutive years to verify the yield response of wheat variety Prodip to different doses and split applications of N fertilizer to determine appropriate N dose and application method for increasing NUE and grain yield of wheat. The treatments comprised of 12 combinations of three doses of nitrogen (80, 100, and 120 kg/ha) from urea, which were assigned in the main plots and four methods of N splitting viz., application of all N as basal; 2/3 rd basal plus 1/3 rd as top dress at crown root initiation (CR1) stage; 1 / 2 basal plus 1 / 2 as top dress at CR1 stage; and 1/3 rd basal with 1/3 rd as top dress at CR1 plus 1/3 rd as top dress at 1st node stage which were tested in the sub plots. Higher yield was achieved from N rate of 120 kgiha applied as three equal splits of one-third as basal during final land preparation, one-third as top dressing during CR1 and the rest one-third top dressing at first node stage. The yield advantage of wheat due to N treatments was attributed to higher thousand grain weight and spikes/m 2 . Nitrogen content in wheat grain and straw was not affected significantly by different N treatment and their combinations, whereas plant N uptake was significantly influenced by N rate and N splitting and also due to the interaction of N rate and N splitting. Total N uptake was maximum under N rate of 120 kg/ha applied as three equal splits as 1/3 rd basal with 1/3 rd as top dress at CR1 plus 1/3 rd as top dress at 1 st node stage. Split applications of sub-optimal dose of N (80 kg/ha) resulted in negative gain in apparent NUE, but split applications, especially three split applications (1/3 rd basal, 1/3 rd at CR1, and 1/3 rd at 1 st node stage) of higher dose of N (100 and 120 kg/ha) resulted in positive gain in apparent NUE.

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The efforts of modern civilization to create an environment to meet human aspirations have successfully resulted in constant improvements of our lifestyle, but it has increased risks to human and ecological health. This situation has motivated many scientists throughout the world to analyze the environmental factors that can affect our health or ecology and to calculate the levels of risk. In Bangladesh development activities and utilization of the river pose a great threat to the health of the existing natural environmental system, particularly for the important river Buriganga of the capital city, Dhaka, due to the pollution of the river water. A study was carried out to observe the ecological health hazards of the Buriganga river and their risk to human health. Several random samples of water were collected from different spots on the river from September to December 2006. The samples were analyzed to determine water quality and associated environmental health risks. The study revealed that the water is high in biological oxygen demand (BOD), chemical oxygen demand (COD), phosphate (PO4 -3), ammonia, organic matters and nutrients, etc. It also revealed huge environmental health risks and possible ecological disruption of this river. Finally, the research recommends a sustainable policy framework on how the pollution could significantly be reduced by using different appropriate measures. Key words: Environmental health risk, ecological disruption, sustainable policy, water quality, Buriganga river, Bangladesh  doi: 10.3126/hn.v3i0.1915 Hydro Nepal:Journal of Water, Energy and Environment Issue No. 3, July 2008. Page: 25-28