Estimation of human maximum tolerable intake for methylmercury based on two recent studies in monkeys

Results of long-term toxicity studies of methylmercury (MeHg) in monkeys have been reported. The aim of this study was to estimate the threshold body burden, blood level and threshold daily intake (TDI) of MeHg for monkey and human. The concepts of this study stood on that body burden of MeHg would follow the accumulation theory, and that the more intake of MeHg, the earlier the neurotoxicity appeared, vice versa. The threshold blood level (TBL) of monkey was estimated to be 0.71 as Hg mg/L and the body burden was estimated to be 4.83 as Hg mg/kg. The TDI was estimated to be 0.025 as Hg mg/kg day. In human, the TBL was estimated with compensation by elimination constants of human and monkey. The blood threshold limit and TDI of human were estimated to be 0.33 as Hg mg/L and 0.0046 as Hg mg/kg day, respectively. The estimated body burden was 0.46 as Hg mg/kg.