Estimation of fish consumption and methylmercury intake in the New Jersey population

Despite scientific attention to the toxicology of methylmercury (MeHg), little is known about population-based exposure to this compound. In this study, fish consumption and MeHg intake were estimated based on a seven-day recall survey of fish consumption among 1000 randomly selected New Jersey residents. Survey data were reported on a per-meal basis, and the fish species/dishes consumed at each meal were identified. Portion sizes for each meal were reported or estimated. To correct a possible bias due to underrepresentation of infrequent consumers, several schemes for weighting fish consumption data were investigated. MeHg concentration for most fish species was estimated from the National Marine Fisheries Service database or from recent United States Food and Drug Administration data. Commercial fish accounted for about 95% of all consumption. Mean fish consumption is estimated for all New Jersey adult consumers at 50.2 g/day (90th percentile = 107.4 g/day) and for women 18-40 years old (childbearing age) at 41.0 g/day (90th percentile = 88.1 g/day). Mean MeHg intake is estimated for all New Jersey adult consumers at 7.5 micrograms/day (90th percentile = 1.79 micrograms/day) and for women 18-40 at 6.3 micrograms/day (90th percentile = 14.8 micrograms/day). When MeHg concentrations are adjusted to account for the possible overestimation of current concentrations by the 20-year-old National Marine Fisheries Service database, it is estimated that MeHg intakes may be about 70-80% of unadjusted estimates. Based on these analyses, it is estimated that 21-30% of New Jersey women 18-40 and 5-8% of all New Jersey adults exceed their respective U.S. Environmental Protection Agency Reference Doses for MeHg. Because of uncertainty associated with the Reference Doses, exceeding the U.S. Environmental Protection Agency guidelines does not necessarily correspond to adverse effects on consumers or their fetuses.