JECFA 61st Meeting — Methylmercury (WHO TRS 922)
Summary
The Joint FAO/WHO Expert Committee on Food Additives 61st meeting (Rome, June 2003, report published 2004 as WHO TRS 922) re-evaluated methylmercury and established the international provisional tolerable weekly intake of 1.6 µg MeHg/kg body weight per week, replacing the prior PTWI of 3.3 µg/kg/wk. The 1.6 µg/kg/wk PTMI is anchored on developmental neurotoxicity observed in cohort studies of children exposed in utero through maternal seafood consumption (Faroe Islands and Seychelles cohorts), with a 6.4 µg MeHg/L maternal hair concentration as the no-observed-adverse-effect level translated to dietary intake.
| Parameter | Value |
|---|---|
| PTWI | 1.6 µg MeHg/kg b.w./week |
| Prior PTWI (replaced) | 3.3 µg MeHg/kg b.w./week |
| Critical endpoint | Developmental neurotoxicity (in utero exposure through maternal seafood) |
| Cohort basis | Faroe Islands and Seychelles |
| Maternal hair NOAEL anchor | 6.4 µg MeHg/L (calculated from BMDL) |
| Establishing meeting | JECFA 61st (June 2003) |
| Report | WHO Technical Report Series 922, 2004 |