Abstract:
Heavy metals pollution in aquatic environments known as a major problem contributed to
human health risks. The studies on this pollutant through bioindicators organisms such
oyster from species Crassostrea iredalei is important to control their sources and to
manipulate the pollutants. The concentrations of Cd, Mn, Cu, Zn and Pb in tissue of
Crassostrea iredalei, sediment and surrounding water was measured and the data was
analysed using one way ANOVA and correlation test to detect the relationship between
sampling periods and between oyster tissue , sediment and water. The highest
concentration of metals in oyster tissue was Zn (940.65 ± 531.4 μgig), followed by Cu
(40.08 ± 24.35 μgig), Mn (22.56 ± 42.72μglg), Cd (2.42 ± 1.46 μgig) and Pb (1.15 ± 2.97
μgig). Concentrations of Cd, Cu and Zn were exceeded the maximum level allowed
according to Food Act 1983. Metals in sediment were dominated by Mn (381.78 ±
237.56 μgig) and Zn (41.04 ± 17.24μglg), others were Pb (20.66 ± 8.95 μgig), Cu (7.02 ±
2.49 μgig) and Cd (0.41 ± 0.12 μgig). Concentrations of heavy metals in surrounding
water were Zn (300.96 ± 492.08 μg/L), Pb (14.49 ± 19.75μglL), Cu (6.97 ± 8.6lμglL),
Mn (5.43 ± 5.94μglL), Cd (1.96 ± 2.44 μglL). There was no correlation between metal
concentration in oyster tissue and in sediment for all five metals. Otherwise only Zn
represented strong positive (r = 0.650) (p < 0.05) relationship in oyster tissue and
surrounding water.
