Levels of toxic metals in edible fish from a wetland of India

The present study revealed that fish cultivated in East Calcutta (Kolkata) Wetland (a Ramsar site) and marketed in markets of South Kolkata had heavy metals lead, cadmium, and mercury above the standard tolerance limit and arsenic was found to be below the limit. These fish mainly Oreochromis niloticus Linnaeus and Labeo rohita Hamilton on being cooked had contamination of lead, mercury, cadmium and arsenic at lower levels compared to uncooked fish but were above the tolerance limit except in case of arsenic. Mercury content of both water and fish of this wet land reached such a level, which may be injurious to human health. Heavy metal released from effluents after reaching wetland water are transferred to fishes cultivated in these ponds and finally to human beings through food chain. So the food we unknowingly consume and assume it to being safe might be contaminated with hazardous toxic heavy metals.