Mercury and cadmium distribution in yellowfin tuna (Thunnus albacares) from two fishing grounds in the Indian Ocean near Sri Lanka.

Mercury (Hg) and cadmium (Cd) are contaminants of great environmental concern due to their natural and anthropogenic origin, their ability of bioaccumulate through the food chain and their harmful effects on human health. In this study, the Hg and Cd accumulation in the muscle of 65 yellowfin tuna (Thunnus albacares) collected from two different catching sites of the Indian Ocean near Sri Lanka were evaluated. The samples were mineralized using microwave accelerated digestion, and the metals were detected by atomic absorption spectroscopy (AAS). The metal levels were not significantly different between the two sites (p > 0.05), and the average Hg and Cd concentrations were 0.48 ± 0.35 mg/kg and 0.017 ± 0.024 mg/kg, (wet weight basis) respectively. Only 6 (9.2%) and 2 samples (3.1%) exceeded the European Commission limits for Hg (1 mg/kg) and Cd (0.01 mg/kg), respectively. A comparatively strong positive correlation was observed between the THg concentration and the weight of the fish. However, there was no clear relationship between the concentration and size for Cd. These findings provide an understanding of the Hg and Cd distribution in yellowfin tuna in two fishing grounds in the Indian Ocean near Sri Lanka.

Mercury and cadmium in swordfish and yellowfin tuna and health risk assessment for Sri Lankan consumers.

Commercially important marine fish, yellowfin tuna (YFT), and swordfish (SF), collected from the Indian Ocean around Sri Lanka were analysed for mercury (Hg) and cadmium (Cd) content. The ranges for Hg were < 0.07-1.60 and < 0.07-4.30 mg/kg, while for Cd < 0.006-0.134 and 0.006-0.180 mg/kg in YFT and SF, respectively. In SF 13.3% and in YFT 9.2% exceeded the 1 mg/kg limit for Hg, while 3.1% of YFT exceeded the 0.1 mg/kg limit for Cd. All other samples were well below the maximum limits. Human health risk assessment was investigated using Estimated Daily Intake, Total Hazard Quotient, Hazard Index, and Provisional Tolerable Weekly Intake values for Hg and Cd. The data indicated that the current YFT and SF consumption pattern in Sri Lanka poses no threat to consumer's health. However, further research and awareness on food safety aspects is needed on specific groups such as children and for areas in which consumption of seafood is high.