Correlation of heavy metals content in shell and tissue of smoked Corbicula Fluminea (Etak)

Bivalve bio accumulate metals are useful as sentinel organisms for assessing the bioavailability of metal contaminants in aquatic ecosystems. Malaysian clams can be contaminated with toxic and heavy metals which are cumulative poison through long term ingestion. Corbicula fluminea which is one of the income sources that has become potentially important traditional food in Kelantan, was categorized as filter feeder organism which accumulate heavy metals from contaminated river or water stream and being absorbed from the shell into the soft tissue. Frequently, tissue metal concentrations are used by environmental monitoring studies to evaluate the potential exposure and the effects scenarios. However, bivalves may accumulate certain metals such as Cd, Cr, Cu, Fe, Pb and Zn to a significant extent in shells. As the water contamination increase at continuous rate, this clam was suspected contaminated. Lately, there are numerous reports in local newspapers that claim cause of health effects due to eating contaminated C. fluminea. Currently, there is no specific analysis showed the heavy metals content correlation between the shells and tissue from the contaminated C. fluminea. There may have a possibilities whether the heavy metals content from the tissue being effected from the shells, which is more exposed to the environmental problem and smoked method. Therefore, the purpose of this study is to analyse the heavy metals correlation between the shells and tissues content of smoked C. fluminea to achieve the permeable limits set by Malaysian Food Regulation 1985 (MFR) and FAO/WHO (1984). In this research, the contamination of C. fluminea was identified in term of heavy metal contamination across this smoked processing stage. The heavy metal analysis (Cd, Cr, Cu, Fe, Pb and Zn) were carried out using acid digestion and identified using Perkin Elmer PinAAcle 900F Atomic Absorption Spectrometer. Experimental results revealed that there is no correlation between the shells and the tissues in term of heavy metals contamination. The results showed all the heavy metals concentrations (µg/g) in the soft tissue of smoked C. fluminea (Cd: 1.16±0.09 µg/g, Cr: 3.42±0.32 µg/g, Cu: 34.93±7.02 µg/g, Fe: 211.23±24.20 µg/g, Pb: 2.34±0.24 µg/g and Zn: 110.62±11.96 µg/g) while for the shell (Cd: 0.48±0.16 µg/g, Cr: 6.08±0.70 µg/g, Cu: 0.56±0.07 µg/g, Fe: 25.86±2.64 µg/g, Pb: -60.72±5.29 µg/g and Zn: 9.53±0.91 µg/g). The range of heavy metals accumulated in soft tissues and shells were as followed: Soft tissues (Fe > Zn > Cu > Cr > Pb > Cd) ; Shells (Fe > Zn > Cr > Cu > Cd > Pb). The results obtained were compared with the permissible limits set by Malaysian Food Regulations 1985 (Cd: 1.0 µg/g, Cu: 30.0 µg/g, Pb: 2 µg/g and Zn: 100.0 µg/g) and FAO/WHO 1984 (Cr: 13 µg/g and Fe: 100.0 µg/g). The results of heavy metals indicated that the Cd, Cu, Pb, Fe and Zn are beyond the permissible limits set by Malaysia Food Regulation 1985 and FAO/WHO (1984). This study successfully determine the baseline concentration of the heavy metals content in shell and soft tissue of C. fluminea and their possible source from the environment.