JECFA — Methylmercury Provisional Tolerable Weekly Intake (1.6 µg/kg b.w./week)

The Joint FAO/WHO Expert Committee on Food Additives, at its 61st meeting in June 2003 (report published 2004 as WHO Technical Report Series 922), established the provisional tolerable weekly intake for methylmercury at 1.6 µg MeHg/kg body weight per week, replacing the prior PTWI of 3.3 (JECFA 61st). The PTWI is anchored on developmental neurotoxicity observed in cohort studies of children exposed in utero through maternal seafood consumption (Faroe Islands and Seychelles cohorts), translated from a maternal hair NOAEL of 6.4 µg MeHg/L through standard pharmacokinetic conversion (JECFA 61st).

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 through maternal seafood)
Cohort basis	Faroe Islands and Seychelles
Maternal hair NOAEL	6.4 µg MeHg/L
Establishing meeting	JECFA 61st (June 2003)
Report publication	WHO Technical Report Series 922, 2004

The EFSA 2012 re-evaluation lowered the EU TWI to 1.3 µg/kg b.w./week with adjustment for n-3 long-chain polyunsaturated fatty acid coefficients in fish (EFSA Hg 2012); the JECFA 1.6 PTWI remains the international Codex-aligned value (JECFA 61st).

Sources

• JECFA 61st — JECFA 61st meeting, 2003 (WHO TRS 922, 2004). Evaluation of Certain Food Additives and Contaminants.