First Draft Statement on the Effects of Mercury on Maternal Health

This is a paper for discussion. This does not represent the views of the Committee and should not be cited.

Introduction

1.               As part of the current programme of work on the maternal diet initiated by the Scientific Advisory Committee on Nutrition (SACN), the COT agreed to prioritise papers on iodine, vitamin D, dietary supplements, and heavy metals including lead, mercury, cadmium, and arsenic, each to be considered in separate papers.

2.               In March 2025, the discussion paper on the on the effects of mercury on maternal health was presented to the Committee (TOX/2025/03). This paper was a review of the available data on toxicity of inorganic mercury and methylmercury (MeHg) to maternal health focusing on maternal outcomes and development effects on the fetus or embryo. In the current statement a summary of the toxicity of mercury has been provided but most of the studies identified by literature searches in the discussion paper have not been included in this statement as the Committee concluded the recently published data only confirmed the current knowledge on the toxicity of inorganic and MeHg and did not constitute a basis for revising the current health-based guidance values (HBGVs).

3.               Since the review of the discussion paper, at the request of the Committee, a section on exposure to mercury from dietary supplements has been included in this draft statement and the absorption, distribution, metabolism, and excretion (ADME) section has been simplified and checked for consistency. The UK Governments advice on foods to avoid during pregnancy has been reiterated in the conclusions and the fact that inorganic mercury and MeHg could not be separated in the exposure data has also been addressed in the conclusions.

4.               The draft statement (Annex A) includes a summary of ADME and toxicity of mercury, the derivation of HBGVs for MeHg and inorganic mercury, an exposure assessment from all major sources including food, drinking water, soil and air, the risk characterisation and conclusions.

Questions for the Committee  

5.               The Committee are asked to consider the following questions:  

a)    Are Members content with the layout and structure of the statement? 

b)    Do Members agree with the risk characterisation and conclusions? 

c)     Does the Committee have any further comments on the content of the statement?