Mercury, Cadmium and Lead Levels in Three Commercially Important Marine Fish Species of in Sri Lanka
B.K.K.K. JINADASA1*, L.R.S. RAMEESHA, E.M.R.K.B. EDIRISINGHE AND R.M.U.S.K. RATHNAYAKE
Most heavy metals which bio-accumulate in fishes, especially predatory species do not have any biological significance or beneficial use, but due to the presence of heavy metal fish can pose a health risk to consumers. The objective of this research is to determine mercury (Hg), cadmium (Cd), and lead (Pb) levels in samples of yellowfin tuna, Thunnus albacores (n=25), swordfish, Xiphias gladius (n=35), and red snapper, Lutjanus sp (n=12). Samples were prepared by dividing edible parts into small pieces and homogenizing. Total Hg was measured by cold vapor atomic absorption spectrometry whereas the Pb and Cd were analysed by graphite furnace atomic absorption spectrometry after microwave-assisted digestion. Swordfish contains highest mercury and cadmium concentrations while yellowfin tuna contained the highest lead concentrations. The mean concentrations of heavy metals in fish muscles were found to be 1.24± 0.72 mg/kg (Hg), 0.13±0.83 mg/kg (Cd) and 0.03±0.04 mg/kg (Pb) in swordfish and 0.39± 0.19 mg/kg (Hg), 0.02±0.02 mg/kg (Cd) and 0.06±0.06 mg/kg (Pb) in yellowfin tuna. In red snapper concentrations were 0.17± 0.06 mg/kg (Hg), 0.02±0.01 mg/kg (Cd) and 0.04±0.05 mg/kg (Pb).