An intervention analysis for the reduction of exposure to methylmercury from the consumption of seafood by women of child-bearing age

A previously developed exposure model was used [Risk Anal. 22 (2002) 689] to assess the effectiveness of various advisory scenarios on minimizing mercury (Hg) blood levels via the consumption of commercial seafood, both finfish and shellfish. This exposure model was developed to predict levels of Hg in blood in women of child-bearing age in the US based on the frequency of seafood consumption, the amount of seafood consumed per serving, and the types of seafood consumed. Steady-state relationships that employed descriptive statistics to account for toxicokinetic variation were used to predict levels of Hg in blood. The model incorporates an uncertainty dimension that is intended to represent the range of plausible interpretations of the data. The predictability of the model was confirmed via the use of National Health and Nutrition Examination Survey (NHANES) blood Hg data. In the present analysis, the model was used to predict the impact of limitations in the amount or types of seafood consumed on blood Hg levels. Specifically, simulations for various advisory scenarios were developed on the basis of limitations on total consumption of seafood, elimination of the consumption of certain species altogether, and/or a combination of both. In the baseline model, the median (uncertainty) estimates for the 50th, 95th, and 99th per capita population percentiles were 1.25, 8.2, and 16.1 ppb blood Hg, respectively. After restriction of seafood consumption to no more than 12 oz/week, the median (uncertainty) estimates for the 50th, 95th, and 99th per capita population percentiles were 1.22, 6.8, and 10.6 ppb blood Hg, respectively. Elimination of MeHg species, with average concentrations above 0.6 ppm, resulted in very modest decrements in Hg blood levels, in comparison to either the baseline or the reduced consumption scenarios. These results suggest that strategies to reduce MeHg exposure by reducing the amount of fish consumed (e.g., 12 oz/week) are more effective at eliminating the high end of the exposure distribution than are strategies intended to change the types of fish consumed.