STUDY OF CONCENTRATION OF SOME TOXIC AND ESSENTIAL ELEMENTS IN MARINE WATER, SEDIMENT AND THEIR IMPACT ON MARINE BIOTA

摘要

Baseline concentrations of Pb, Cd, Hg, Cr. Co, Ni, Mn, Cu, Fe, Zn have been studied in marine water from Cox's Bazar sea beach in Bangladesh using FAAS followed by pre-concentration method. To find out any impact of these metals on marine environment, sediment and snail from the same location were also analyzed. The levels of Pb, Cd, Cr, Co, Ni, Mn, Cu, Fe, and Zn except Hg were significantly high in marine environment of Bangladesh. For comparison water, sediment and snail from reference area were also analyzed. Significant differences in metal concentrations were observed between contaminated and reference area. Levels of metal in low tide water and sediment were much higher than that of high tide ones. The concentrations of Pb, Cd, Co, Cr, Ni, Mn, Cu, Fe and Zn in water were found in the range (μg/L) 107.36 - 266.67, 23.43 - 36.12, 64.44 - 112.68, 10.59 - 55.56, 80.89 - 180.83, 52.58 - 138.54, 17.82 - 43.42, 316.77 - 1667.70 and 9.44 - 48.48, respectively. Concentrations of these metals in sediment (mg/kg) were 7.03 - 16.67, 0.59 - 1.46, 4.93 - 20.83, 35.40 - 90.2, 14.14 . 44.04, 196.76 - 678.67, 2.94 - 8.39, 7759 - 27924 and 20.61 - 43.67, respectively. The level of toxic elements was found much higher in water, sediment and snail compared to reported values. The unusual death of snail may be due to the elevated levels of toxic metals in marine water and sediment.