[Levels of mercury in hair among pregnant women in Iceland].

Introduction: To limit exposure to methylmercury several countries have implimented specific advice on fish intake to pregnant women as well a measuring compliance through regular human biomonitoring. Despite fish intake being relatively high in Iceland, human biomonitoring data on mercury is scarce.

Materials and mehods: We measured mercury in hair from 120 pregnant women recruited in 2021 from the the Reykjavik Capital area. At recruitment, information on fish intake during the past four months was recorded. Hair mercury concentrations were compared to existing health based guidance values and associatons with fish intake was explored.

Results: Mean (standard deviation) mercury concentration in hair was 0.48 μg/g (0.33). All participants had concentrations in hair below 1.8 μg/g, which corresponds to the hair value that the tolerable daily intake set by the European Food Safety Authority is derived from, while 5% had concentrations above 1.1 μg/g, which corresponds to the hair value that the US-EPA reference dose is derived from. Mean mercury concentrations in hair increased in a dose dependent manner (p for trend p<0.001) from 0.25 μg/g among women who consumed fish ≤ 3/month (n=24) and up to 0.80 mg/g among those consuming fish 3-4/ week (n=16). The few (n=3) women who reported to have eaten shark (p<1/month) were all at the higher end of the exposure distribution.

Conclusion: Our results suggest that exposure is generally below the tolerable daily intake set by EFSA but may in some women exceed the reference dose established by the US-EPA.