Maternal-infant biomarkers of prenatal exposure to arsenic and manganese

Because arsenic (As) and manganese (Mn) are able to pass the placenta, infants among exposed populations may be exposed toconsiderable levels in utero. The main objective of this paper is to evaluate infant toenails, hair, and cord blood as biomarkers ofprenatal exposure to As and Mn and determine the relationship between maternal and infant As and Mn concentrations in thesebiomarkers. Of the 1196 pregnant women in Bangladesh who were monitored throughout pregnancy until 1 month post-partumand completed all study visits, we included 711 mother–infant pairs who had at least one maternal and one infant biomarker ofexposure available for analysis. Toenail and hair samples were collected from the women during the first trimester and 1 monthpost-partum and from the infants at the age of 1 month. Cord blood was collected at the time of delivery. Maternal toenailconcentrations were correlated with infant toenail concentrations for As and Mn (n=258, r=0.52, 95% CI: 0.43–0.60, Po0.0001 andr=0.39, 95% CI: 0.28–0.49, Po0.0001), respectively. Similarly, maternal hair concentrations were correlated with infant hair As(n=685, r=0.61, 95% CI: 0.56–0.65, Po0.0001) and infant hair Mn (n=686, r=0.21, 95% CI: 0.14–0.28, Po0.0001). Cord blood Aswas correlated with infant toenail and hair As, although cord blood Mn was only correlated with infant toenail. Toenails and cordblood appear to be valid biomarkers of maternal–fetal transfer of As and Mn, whereas hair may not be a suitable biomarker forin utero exposure to Mn.Journal of Exposure Science and Environmental Epidemiology advance online publication, 26 August 2015; doi:10.1038/jes.2015.45Keywords: arsenic; cord blood; fetal transfer; manganese; toenailsINTRODUCTIONConcentrations of arsenic (As) and manganese (Mn) in Bangla-desh’s drinking water have been of great public health concernwith ~31% of water samples exceeding 50μg/l of arsenic (WHO’sguideline is 10μg/l) and 42% exceeding WHO’s former health-based guideline of 400μg/l of manganese (as of 2011, there is noWHO guideline for Mn).