Risk assessment of methylmercury based on internal exposure and fish and seafood consumption estimates in Taiwanese children

Fish and seafood consumption is a major source of human exposure to methylmercury (MeHg). This study evaluated the potential health risk of MeHg in Taiwanese children from fish and seafood consumption using a toxicokinetic model, hazard quotients and hazard indices (HIs). Two biomonitoring programs provided an important resource for blood specimens for assessing MeHg exposure in human populations. For internal exposures, total mercury (THg) was measured as a biomarker of MeHg in whole blood (WB) and red blood cells using inductively coupled plasma mass spectrometry and cold-vapor atomic absorption spectroscopy, respectively. The THg concentrations were used to estimate MeHg concentrations. Consumption of fish and seafood was assessed using the National Food Consumption database in Taiwan, while mercury concentrations in edible fish and seafood were collected from published studies in Taiwan. Our results indicated that 1) the highest median THg (representing estimated MeHg) daily intakes were found to decrease with increasing age in children consuming saltwater fish for age groups 0-3, 4-6, 7-12, and 13-18 years: 0.03 > 0.02 > 0.017 > 0.007 (mu g kg-BW-1 day(-1)); 2) HI greater than one, based on WB-THg, was found in 28% of 4-6-year-old children and 3) internal exposure estimates based on WB-THg, though slightly higher, were comparable to those based on fish and seafood consumption. The results support the use of dietary intake estimates as surrogates for internal blood MeHg levels in Taiwanese children to assess their exposure.