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Toxicity of chromium, copper and zinc to freshwater clam (<i>Galatea paradoxa</i>) (Born, 1778) (Bivalvai, Donacidae))

LLC Ugwu
BO Mgbenka
NB Ekanem


The toxicity of copper (Cu), Chromium (Cr) and Zinc (Zn) on freshwater clam, Galatea paradoxa Born (=Egerea radiate Lamarck was investigated in three static bioassays for 96 hours. The three toxicants were introduced at 0.5, 1.0, 10.0, and 15.0mgL-1 concentration in river water to twelve (12) clams (mean weight: 250 ±0.2g) in 10litres capacity plastic basins. Three other basins devoid of any of the metals were used as control. The results revealed that death occurred in the water treated with toxicants but no death occurred in the control experiment, indicating that all deaths recorded were due to the toxicants. The 96-hour LC50 values obtained were 2.51mgL-1 for copper, 91.2mgL-1 for zinc indication that copper was most toxic to the clams followed by zinc and chromium.

Bio-Research Vol. 3(1) 2005: 72-76