Assessment of selected heavy metals Perna viridis mussel and surface seawater in the coastal area of Pasir Gudang, Malaysia

Abstract

Owing to its nutritional values, consumption of cultured marine bivalve such as P. viridis has gained popularity in many countries including Malaysia. Besides, the use of P. viridis as biomonitoring agent for heavy metal pollutions in coastal waters has also been suggested. The previous study on levels of heavy metal contaminants in P. viridis collected from Kampung Pasir Putih, Pasir Gudang, Johor was reported in 2013. Because temporal changes might have occurred at this important harvesting site, this present research acquires public health consideration. Concentrations of lead (Pb), cadmium (Cd) and copper (Cu) as well as mercury (Hg) in the soft tissue of P. viridis and surface seawater sampled from the site during January to March 2015 were investigated using Flame Atomic Absorption Spectrometry (FAAS) and Flow Injection Mercury System (FIMS), respectively. Results revealed significantly higher concentrations of these heavy metals in P. viridis (p < 0.05) than that of surrounding surface seawater samples. Alarmingly, the ranges of concentrations for Pb (4.27-6.55 µg/g) and Cd (1.55-2.21 µg/g) in P. viridis mussel (wet weight) exceeded the maximum permitted proportion prescribed by the Malaysian Food Act. Furthermore, the concentrations of Pb (2.62-3.62 mg/L), Cd (0.72-0.78 mg/L), Cu (0.27-0.38 mg/L) and Hg (0.21-1.49 µg/L) in surface seawater samples exceeded the Malaysia Marine Water Quality Criteria and Standards (MMWQCS). While no significant correlation (p > 0.05) was found between Hg (r = -0.110) in P. viridis mussel and the surrounding surface seawater, significant correlations (p < 0.05) were observed for Pb (r = 0.787), Cd (r = -0.620) and Cu (r = -0.794). Considering the high concentrations of heavy metals found in both P. viridis and surface seawater at the study site, the negative impacts on human health following consumption of this seafood product could not be ruled out. Therefore, continuous assessment on this aspect proves to be relevant.