Total mercury and methylmercury in commercial marine species from the Goa coast: Constraints on risk assessment and environmental issues

摘要

Mercury (Hg) is a toxic element which accumulates in fish and other aquatic organisms from various sources and poses potential risk to the consumers. Methylmercury (MeHg), the common organic species of mercury, usually forms in aquatic environments and is known for neurotoxicity. In this study, the concentration of total Hg and MeHg in 12 commercial species of fish, shellfish, prawn, and crab from coastal areas of Goa were investigated. The total Hg contents varied between 18.5-260 mu g/kg; while the concentration of MeHg had a range of 7.2-129 mu g/kg. Both the ranges were well below the values recorded at other polluted coastal sites and also meet the permissible limits for human consumption. The interspecies comparison shows species from pelagic and benthic habitats with different food habits have significant difference in body loads of total Hg and MeHg, which increases across the trophic levels. The exposure to higher level of Hg in sediment is likely responsible for enhanced bio-concentration of Hg in benthic species as compared to the values in pelagic fishes.