Abstract:
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.
