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crossed the maximum permissible limit. In dry season the level of pollution was much high than in wet season. That indicates the water of Buriganga was not safe for drinking purposes, irrigation, fisheries, recreational activities and various industrial uses for most of the times of year.

In Bangladesh, the tannery solid wastes are converted to protein-concentrate to be used as poultry feed, fish feed, and in production of organic fertilizers. Over the last several years it is a common phenomenon in the largest tanning area of the country, the Hazaribagh tannery area at the south-east part of Dhaka city. One of the major concerns of these activities is the heavy metals, especially chromium, used in the tanning processes. A total of 18 samples were collected to study the heavy metal status of protein-concentrate production in the tanning area at various stages from the source to the final product, and to compare this with the imported ones. The various types of solid waste processing for protein-concentrate production were covered in sampling, and along with the heavy metal status these processes were studied comprehensively. The maximum chromium content of the solid waste was found to be 3.2 %. The final products sampled at two different places contained as high as 2.49 % and 1.94 % chromium. Cadmium, lead, arsenic, and mercury contents of all samples were also determined. The detected maximum and minimum concentrations of these elements were found to be: 3.888 ppm and 0.991 ppm for cadmium, 30.114 ppm and 7.577 ppm for lead, 2.212 ppm and 0.099 ppm for arsenic, and 13.916 ppm and 0.166 ppm for mercury.

In the north-eastern part of Dhaka the 'Turag River' extends over Ashulia thana with a few branches. The north-eastern part of Ashulia thana mainly constitute low lands with a physiography of Madhupur Tract interlaced with Brahmaputra Floodplain. Monsoon extends over these lands from May to October and from July to October these lands remain flooded with a water depth of more than 180 cm to less than 275 cm due to surface runoff of rain water and overflow of the river canals. The area under water during this four month period can be used for economic applications such as various types of fishery as well as enhancing the present recreational applications. For these purposes the physical, chemical, and biological aspects of the water are studied to evaluate its suitability for the applications. The study was held over the period of July through December, 2006, samples being taken once every month. The physical parameters covered transparency, odor, temperature, salinity, EC, TSS, and TDS. The chemical parameters of water studied were pH, DO, BOD 5 , COD, hardness, NO 2 ---N, NO 3 ---N, PO 4 3---P, SO 4 2---S, Cl-, Na, K, Ca, Fe, Ni, Cu, Zn, Cd, Pb, and Hg. Among the biological parameters 'phytoplankton' and 'zooplankton' were qualitatively identified in microscopic observation up to genera. From July to October the water was transparent and of good odor, temperature ranged from 28.2 O C to 24.6 O C, salinity within 0.58 to 0.83 mg/L, EC within 250 to 608 µ mho/cm, TSS 0.42 to 0.82 mg/L, and TDS within 2.8 to 5.2 mg/L. Among the chemical parameters, pH ranged from 6.6 to 7.4, DO within 6.4 to 6.9 mg/L, BOD5 within 1.5 to 3.28 mg/L, COD within 3.04 to 12.89 mg/L, hardness 26.08 to 37.5 mg/L, NO 2 --N from undetectable to maximum 0.562 mg/L, NO 3 --N within 0.539 to 2.158 mg/L, PO 4 3 --P 2.35 to 2.75 mg/L, SO 4 2 --S 0.23 to 0.29 mg/L, Cl-1.65 to 6.16 mg/L, Na 3.6 to 12.5 mg/L, K 9.7 to 11.5 mg/L, Ca 6.52 to 14.82 mg/L, Fe 0.1269 to 0.5062 mg/L, Ni 0.028 to 0.050 µg/L, Cu 0.028 to 0.043 mg/L, Zn 0.023 to 0.048 µg/L, Cd 0.0023 to 0.0043 µg/L, Pb 0.043 to 0.093 µg/L, and Hg was not detected at ppb level. Among the biological parameters a number of phytoplankton were identified covering the classes of Bacillariophyceae, Chlorophyceae, Euglenophyceae, and Cyanophyceae. The zooplanktons included the orders Cladocera and Copepoda within the class Crustacea of phylum Arthropoda.

Two pot experiments were conducted at the Dept. of Soil, Water and Environment, University of Dhaka to examine the effects of Zn on red amaranth (Amaranthus sp.) and rice (Oryza sativa). The soil collected from Bhaluka, Mymensingh (Chandra series), had the following general characteristics; pH 6.0, E.C 134 μS cm-1, organic matter 2.20%, organic carbon 1.27%, total N, P, K 0.024, O.07 and 0.05 % respectively. The total Zn content was 20 ppm and the texture was silty loam. Four Zn levels were maintained by treating the experimental soils with 0, 200, 300 and 400 mg Zn/kg soil. Roots & shoots of red amaranth and rice were collected after 45 and 90 days of sowing respectively. A significant impact of zinc was observed on growth and yield of red amaranth and rice. The concentration of zinc increased with increasing zinc treatment in red amaranth and rice roots, shoots and grain. The length of roots and shoots, the fresh and dry matter production  decreased with increasing zinc levels for red amaranth. In case of Rice the length of roots, shoots and spikelets increased with increasing zinc levels and the highest was observed at 200 ppm Zn. The fresh and dry matter production at first decreased at 200 ppm Zn but increased at 300 and 400 ppm Zn for Rice. The results showed that zinc influenced the growth and yield of red amaranth and rice. Keywords: Zinc; Toxicity; Treatments; Yield; Uptake; Heavy metal.DOI: 10.3329/jbayr.v1i1.6836Journal of Bangladesh Association of Young Researchers Vol.1(1) 2011 pp.79-91

In Bangladesh, among the routes of chromium eco-toxicity, feeds and fertilizer production from tanned skin-cut wastes is the most direct one leading to food chain contamination. The tanning industries of Hazaribagh are processing some 220 metric tons of hide a day with an associated release of 600 -1000Kg of tanned skin-cut waste (SCW) resulting from per ton processed hide. The SCW are protein-rich and are unscientifically used to produce protein-concentrates for poultry and fish feeds, and organic fertilizer. In view of the facts, a huge migration of chromium can happen into poultry products, fish and vegetables, and further bio-magnify into food chain. The target population of this phenomenon is also huge. Regional bio-concentration of chromium was investigated in commercially produced chicken eggs. Though the routes of distribution of this hugely produced protein-concentrates from SCW are unknown, eggs were sampled from Dhaka and its nearby other seven districts covering the central region of Bangladesh. Twelve eggs were randomly sampled from each district's egg stock market while albumen and yolk in each egg were studied separately for all studies. Out of the 192 samples from 96 eggs, dry weight basis mean chromium concentration was found to be 1.9016 ppm with a sample standard deviation of 0.1502. The concentration levels were ranged from maximum of 19.8051 ppm to undetectable levels. Single poultry egg was found to contain a mean chromium content of 23.3809 µg, which exceeds adequate daily dietary intake of children up to 8 years of age as well as corresponds to major part for other age groups. The region-wise physical properties of the eggs were also studied which included USDA size grading by whole weight at raw condition, whole weight ratio of raw condition to complete boiled condition, weight ratio of boiled shell-albumen-yolk, moisture content of albumen of boiled eggs, and moisture content of yolk of boiled eggs. The mean whole weights of eggs at raw condition were within the range of 39.9568 g ('peewee' as per USDA size grading) to 62.4047 g ('large' as per USDA size grading), the mean whole weight ratio of raw condition to complete boiled

Heavy metal pollution is associated with public health concerns. The study was conducted at the vicinity of the Tejgaon industrial area (8 km 2 ) adjacent to Dhaka City Corporation. To investigate the seasonal extent of soil-water ecosystems pollution with chromium discharged from the industries, municipality, and slums, and its transfer co-efficiency into plants or crops.Composite soil, plant and water were randomly collected from industrial sites by GPS guided sampling procedure during wet and dry seasons, processed, and analyzed. Soils were analyzed for particle size distribution (sand, silt and clay), pH, electrical conductivity (EC), total organic carbon,