Mercury in Marine, Freshwater and Aquaculture Species from South India and Human Exposure Risk Assessment

Abstract

We report concentrations of methylmercury (MeHg) and total mercury (THg) in marine, freshwater and aquaculture species from a major fisheries landing center in the east coast of India, Nellore. Concentrations of MeHg were in the range 1.67–105.25 ng/g ww (wet weight). Aquaculture species had lower mercury concentrations than naturally caught marine or freshwater species (p < 0.05). While none of the 242 analyzed samples had MeHg greater than the limits stipulated by food and safety authority in India (250 ng/g) or other countries, dietary exposure analysis for a subsistence fish consuming Indian population for which fish consumption patterns were known revealed that there was a 14.3% probability of exceedance of the US EPA reference dose of 0.1 µg/kg BW/day. The US EPA one-box pharmacokinetic model slightly better predicts the observed hair mercury concentrations in this population when the MeHg absorption efficiency in the human gastrointestinal tract is 1–72% (with a median of 14%) as suggested recently rather than the 91–97% used more commonly.