Abstracts: ISEE 21st Annual Conference, Dublin, Ireland, August 25–29, 2009: Symposium Abstracts: Symposia Presentations
Neurotoxicity from prenatal exposure to methylmercury has been studied but no firm conclusions have been reached on the dose-response relationship, especially at levels of exposure less than 10 ppm. This study has enrolled a total of 1700 pregnant women and their children in Slovenia, Croatia, Italy and Greece to assess the impact of mercury exposure through fish consumption during pregnancy on child neurodevelopment. We present here results at baseline on levels of total mercury (THg) and methylmercury (MeHg) in maternal hair in relation to fish consumption patterns during pregnancy and estimate correlations between THg and MeHg concentrations in maternal hair and between maternal and cord blood.
Maternal hair, blood, and cord blood samples are collected at different times during pregnancy and after delivery. THg in hair is analysed by CV-AAS and, in subjects whose hair THg exceeds 1 ppm, MeHg in hair and blood samples is determined by gas chromatography. We assessed fish consumption through food frequency questionnaires administered during pregnancy and 1–3 months after delivery, respectively.
Mean THg in hair is 0.94 ppm, with 69% <1 ppm and 10% >2 ppm. Less than one serving/week of fresh fish is consumed by 45% of mothers and >3 servings/week by 8%, with a correlation between hair THg and fresh fish consumption (rs = 0.45, P < .0001) during pregnancy. In paired samples, THg in maternal hair and maternal blood are highly correlated (r = 0.88, P < .0001) as well as MeHg in maternal blood and THg in maternal hair (r = 0.78, P < .0001). There is a moderate correlation between THg in maternal hair and MeHg in cord blood (r = 0.57, P < .0001). In maternal hair samples with THg >1ppm, 98% of total mercury is methylmercury.
Current mercury levels in hair are low, but there is a correlation between consumption of fresh fish and hair THg levels.