Concentration of arsenic and mercury in the oysters (Crassostrea iredalei) from Setiu Lagoon, Terengganu

Abstract

The objectives of this study are (1) to determine the concentration of arsenic and mercury in the oysters from the Setiu Lagoon, (2) to show the relationship between the concentration of arsenic and mercury in the oysters, water and sediment and (3) to compare the concentration of the arsenic and mercury to the Malaysian Food Act 1983 safety level whether the oysters are safe for consumption. The arsenic concentration range in the sediment, oysters and water in this study were 9.00 to 36.10 µg/g, 8.20 to 43.90 µg/g (dw) and 0.90 to 4.37 µg/L. While for the mercury concentration, there were in the range of 0.35 to 0.79 µgig in sediment, 0.60 to 0.90 µg/g (dw) in oysters and 0.20 to 13.20 in water. As for the relationship, there were significant association of mercury in the water with the water quality parameter and the time of sampling. While for the arsenic concentration, the relationship between oysters, sediment and water were significantly correlated. There were low correlation between oyster-sediment and water-sediment. The oyster and the water show a moderate correlation (P<0.01) between them. The BCF was higher in the oyster/water than oyster/sediment. Setiu Lagoon was contaminated by arsenic and mercury. The safety limits of the water were exceeding the limit that had been state by WHO, 1993. While for the sediment, the concentration of arsenic and mercury were too high than the earth crust.