Potential health risk assessment of selected metal concentrations of Indian backwater oyster, (Crassostrea madrasensis) from Puttalam lagoon, Sri Lanka

Abstract Oysters are considered as a nutritious seafood, but they can adversely effect on human health due to bioaccumulation potential. The current study was conducted to determine the health risks of mercury(Hg), lead(Pb), cadmium(Cd), arsenic(As), magnesium(Mg), zinc(Zn), iron(Fe) and copper(Cu) in cultured and wild Crassostrea madrasensis collected from Sri Lanka. The samples were collected over 13 months from July 2014-July 2015 and monthly variations of metal concentrations and influence of environment were studied between cultured and wild C.madrasensis . Metal concentrations were analyzed using Atomic Absorption Spectrophotometer and compared with published international standards. The accumulation order of metal concentrations was Zn>Mg>Fe>Cu>Pb>Cd>As>Hg. The mean Hg, Cd, Pb, As, Mg and Fe concentrations showed monthly variations, but not varied within cultured and wild oysters (p>0.05). A significant variation was observed in both month and source of oysters for Zn and Cu concentrations. A positive correlation was observed for mean Cd and Fe concentrations with temperature while other metals were not. The mean Hg concentrations were well below the maximum levels given by Australia New Zealand Food Standards Code (FSANZ2003) and Commission Regulation (EC1881/2006) and China (GB 2762-2017) while the mean Pb concentration was exceeded standards. The Cd level exceeded the EC (1881/2006) while not other two standards. The weekly intakes of Hg, Cu, Fe, and Zn from C.madrasensis were well below the Provisional Tolerable Weekly Intake (PTWI) while, the intake of Cd exceeded PTWI. Hence, the investigation indicated the health risk of consuming C.madrasensis emphasizing continuous monitoring to assure consumer’s health and export-oriented market.