Elevated childhood exposure to arsenic despite reduced drinking water concentrations — A longitudinal cohort study in rural Bangladesh

Abstract

ObjectivesThe aim of this study was to evaluate the massive efforts to lower water arsenic concentrations in Bangladesh. MethodsIn our large mother–child cohort in rural Matlab, we measured the arsenic concentrations (and other elements) in drinking water and evaluated the actual exposure (urinary arsenic), from early gestation to 10years of age (n=1017). ResultsMedian drinking water arsenic decreased from 23 (2002–2003) to <2μg/L (2013), and the fraction of wells exceeding the national standard (50μg/L) decreased from 58 to 27%. Still, some children had higher water arsenic at 10years than earlier. Installation of deeper wells (>50m) explained much of the lower water arsenic concentrations, but increased the manganese concentrations. The highest manganese concentrations (~900μg/L) appeared in 50–100m wells. Low arsenic and manganese concentrations (17% of the children) occurred mainly in >100m wells. The decrease in urinary arsenic concentrations over time was less apparent, from 82 to 58μg/L, indicating remaining sources of exposure, probably through food (mean 133μg/kg in rice). ConclusionDespite decreased water arsenic concentrations in rural Bangladesh, the children still have elevated exposure, largely from food. Considering the known risks of severe health effects in children, additional mitigation strategies are needed.