Three different brick kilns from the same parent material, young Brahmaputra and Jamuna floodplain were selected to assess the lead and cadmium accumulation. Soils and plants from four points such as 250, 500, 1000 and 1500 m away from kilns were collected based on the predicted brick kilns emission distance. Lead (92 mg kg -1 to 214 mg kg -1 ) was found in the elevated levels near brick kiln soils. The alarming news is that plant uptake of Pb in the nearest areas of the brick kilns were significantly higher than the areas far from the brick production location and Pb ranges from 7 to 543 mg/kg. Results showed that both soils and plants from 500 m to 1000 m distance received maximum Pb. The amount of Pb significantly decreases with the increasing distance from the brick kilns. Cadmium varies within the permissible limit in both soils and plant.

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Experiment was carried out to assess the concentration of Zn, Cu, Pb, Fe and Mn in agricultural soil and plant near selected brick kilns. Soils and plants samples were collected from four points such as 250, 500, 1000 and 1500 m away from brick kilns. Three metals were found at elevated levels in the soils near brick kilns such as, Pb (92.5 to 214 mg/kg), Zn (86 to 156 mg/kg) and Cu (24.7 to 46.9 mg/kg). It may be caused due to burning of poor quality coal and fire woods. The uptake of heavy metals in the nearest areas (250 m) of the brick kilns was significantly higher than the areas far from the brick production and their concentrations range from 7 to 543 mg/kg for Pb, 23 to 101 mg/kg for Zn, 10 to 41 mg/kg for Cu, 35 to 1309 mg/kg for Fe and 26 to 126 mg/kg for Mn. Results indicated that soils and plants accumulated maximum amount of micronutrients within 500 to 1000 m distance from brick kilns significantly decreased with distance. Iron and manganese were not polluting the soils near brick kilns but affecting the plants. Therefore, it can be suggested that no agricultural crops should be grown within 1000 m distance from a brick kiln.Dhaka Univ. J. Biol. Sci. 25(1): 75-81, 2016

An investigation was conducted to assess the air quality impact and possible health risk of solid waste disposal on surrounding environment of Matuail landfill site in Dhaka city. Three different locations were selected for soil and plant samples. Leachate samples were collected from active dumping area and fish samples from treated leachate pond. Seven different locations were selected for air quality and health risk assessments. It is found that Cu, Zn and Pb concentrations were high in the soil of dumping and abandoned areas that exceeded the permissible limits. The heavy metal concentrations in plant samples did not show any significant contamination except Cu, Zn and Pb that also exceeded the permissible limits. The concentrations of DO, BOD, COD and TDS of the untreated leachate were found 1.34 mg L 1 , 96 mg L 1 , 1343 mg L 1 and 7120 mg L 1 , respectively that exceeded inland surface water standard but after treatment its concentrations were found within the permissible limits. The presence of heavy metals in leachate sample was not contaminated as it was below the toxic limits. The bioaccumulation of fish sample from treated pond is extremely high of Fe, Mn, Pb and Ni that exceeded the WHO's permissible limits. The air quality results showed that the Matuail landfill surrounding sites did not have an adverse effect. The air pollutants such as NOx, SO2, SPM, PM10, PM2.5 and CO contents are within national standard limits. Overall, the risk assessments demonstrated that potential air emissions from the Matuail Landfill site do not pose public health risks. It is clear that if the dumping landfill site is properly managed by segregating the waste according to their source, then this waste could be used as compost or organic manures. However, by maintaining disposal sites with controlled placement and proper treatment of the waste may reduce the possible adverse impact on air, human health and agrienvironmental eco-systems. Further investigation on the impacts related to the final disposal of solid waste and the future landfill requirement at different composting and a comparative study is suggested.

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