Hair methylmercury levels in U.S. women

The scientific community has recently focused its concerns on possible developmental delays in infants exposed to methylmercury via maternal fish consumption. In this study, the authors reported levels of methylmercury in hair specimens that corresponded to 2820 monthly seafood consumption diaries recorded by U.S. women of childbearing age. In this study, the geometric mean hair methylmercury level for diarists who reported some seafood consumption was 0.36 ppm (one geometric standard deviation [GSD] range = 0.14-0.90 ppm); the corresponding value for diarists who reported no seafood consumption was 0.24 ppm (one GSD range = 0.09-0.62 ppm). Therefore, the mean hair methylmercury level associated with seafood consumption was 0.12 ppm (one GSD range = 0.05-0.32 ppm). The results of this study provide evidence that levels of methylmercury in the U.S. population are quite low. There is a significant contribution to hair methylmercury from sources other than seafood. It is not likely that maternal hair methylmercury levels in the range found in our study would be associated with adverse health effects in children.