Bivalves as Bio-Indicators for Heavy Metals Detection in Kuala Kemaman, Terengganu, Malaysia

Background/Objectives: The objective of this work is to collect representative sample of bivalves, soil and water from Kuala Kemaman. It performs analysis of heavy metal existence and estimate the heavy metals concentration from the collected samples. Method: First sampling allocation for bivalves, water and soil after sampling pre–treatment was applied to remove any impurities from bivalve samples. Digestion by acid was done after drying. Then, analysis was carried out by using atomic absorption spectrophotometer (AAS). Estimation was done in triplicate and results were expressed in ppm on average basis with support of standard reference materials that were always with high confidence interval of the certified values. Findings: High concentration exceeds the Malaysian Food Regulation (MFR 1985) permissible limits for cadmium (Cd) and lead (Pb) were found in bivalve tissues of Polymesoda Expansa and Anadara granosa. However, copper (Cu) and zinc (Zn) levels were below the allowable limit. Heavy metals concentrations in both bivalves (μg/g dry wt) were ranged between 2.3–5.9, 12.8–15.9, 6.8–10.2, 22.9–56.5 and 7–3 for Cd, Cu, Pb, Zn and Fe respectively. Polymesoda Expansa showed a higher tendency to accumulate high concentration of Cu, Zn and Fe. At the same time, Anadara granosa showed a higher tendency to accumulate higher concentration of Cd and Pb, even though samples were collected from the same area. For iron, there is no permissible level according to MFR 1985. However, Fe was slightly higher than WHO 1993 (set value; 5 ppm). Analysis of soil and water for the samples collected from the same area showed that heavy metals concentrations were under permissible level set by Malaysian Food Regulation (MFR), World Health Organization (WHO) and USEPA (1993) regulations. Applications/Improvements: Results show that Anadara granosa have a tendency to accumulate higher concentration of Cd and Pb compared to Polymesoda Expansa where it has a higher tendency to accumulate Cu, Zn and Fe. The concentration of heavy metals in soil and seawater were below the permissible level. In this work, only one time sampling was carried out. Therefore, it is recommended to perform regular monitoring in seasonal basis in order to obtain a clearer picture about the environmental situation in Kuala Kemaman and nearby areas.