Acute Toxicity of Metals: Cu, Pb, Cd, Hg and Zn on Marine Molluscs, Cerithedia cingulata G., and Modiolus philippinarum H

Present study was intended to compare the acute static renewal toxicity tests on marine snail, Cerithidae cingulata and bivalve, Modiolus philippinarum that were performed with Cu, Cd, Pb, Zn and Hg. The 96 h LC sub(50)values for C.cingulata were 0.521, 9.193, 15.507, 8.990 and 0.053 mg.l super(1) and the 96 h LC sub(50)values for M.philippinarum were 0.023, 0.221, 2.876, 2.337 and 0.007 mg.l super(1) in respective metals. This study indicated that mercury was highly toxic to both C.cingulata and M.philippinarum. While lead was resistant metal to both marine molluscs tested. Order of increasing toxicity of metals to C.cingulata was Hg > Cu > Zn> Cd > Pd and to M.philippinarum was Hg > Cu > Cd > Zn > Pb. Safe level concentrations for all 5 metals were also calculated. The LC sub(50)values of the present study may be useful in deriving marine water quality standards in the coastal waters of Gulf of Mannar.