Determination of Water Quality and Selected Heavy Metal in Mud Clams (Polymesoda expansa) as Bioindicator at Benting Lintang, Besut, Terengganu

Anthropogenic activities are the main cause of water quality deterioration which causes severe impacts on aquatic animals and human health. Mud clams (Polymesoda expansa) mostly eaten by people in Southeast Asia especially Terengganu can be exposed to the heavy metal contamination because of their filter feeder behaviour. This study aims to determine the water quality index (WQI) and investigate the selected heavy metal (Cr, Ni, Cu, Zn, Pb) contamination using Lokan (Polymesoda expansa) as a bioindicator at Benting Lintang, Besut, Terengganu. Analysis of water quality parameters was conducted In-situ and Ex-situ which involves 3 stations along the Benting Lintang water body. The heavy metal analysis was determined by using the acid digestion method and ICP-OES. The statistical analysis ANOVA shows the p-value is less than 0.05 proved there are significant different of heavy metal in mud clams between wet and dry season. The water quality at all stations during wet and dry season categorized at class II except station 2 during dry season falls on class III. The class II water quality shows that recreational activities can be done at the study location while extensive treatment is required at the station 2 during dry season. Heavy metal accumulated in mud clams for Cr, Ni and Cu in both seasons still in permissible limit according to FDA (2007), FAO (1983) except Pb and Zn exceeded the limit by Malaysia Food Regulation 1985 (2011). As a conclusion, mud clams are a good bioindicator for heavy metal determination in their surroundings. Frequent water quality monitoring and heavy metals analysis in mud clams should be conducted to ensure food safety and human health in future.