Statement on the findings presented in the Toxicological Profile for Mercury issued by the US ATSDR

The European Food Safety Authority (EFSA) was requested by the European Commission to deliver a statement on the findings presented in the Toxicological Profile for Mercury issued by the US Agency for Toxic Substances and Disease Registry (ATSDR) in 2024. The statement was endorsed by the CONTAM Panel before approval by EFSA. Although some key methodological steps were not fully reported in the ATSDR document, it is unlikely that any major or relevant publications would have been missed. Based on the results presented by ATSDR (2024), including a new 28-day study in rats, there is no need for an update of the 2012 EFSA risk assessment for inorganic mercury, because EFSA considered this study not suitable to derive a reference point for dietary risk assessment. Consequently, the tolerable weekly intake (TWI) of 4 μg/kg body weight (bw), expressed as mercury, is still valid. For methylmercury, varying reporting approaches on the rationale for the methodological choices made during hazard characterisation appear to be the main driver of the differing guidance values. There is no clear indication that the minimal risk level (MRL) for methylmercury derived by ATSDR (0.1 μg Hg/kg bw/day, corresponding to 0.7 μg Hg/kg bw/week) is scientifically more robust than the TWI (1.3 μg/kg bw per week, expressed as mercury) established by EFSA in 2012. Consequently, the current EFSA TWI of 1.3 μg/kg bw per week, expressed as mercury, remains valid. Despite this, the advances in risk assessment methodology and the new evidence becoming available since the last EFSA assessment might merit an update of the 2012 Opinion.