Contribution of household drinking water intake to arsenic and lead exposure among Uruguayan schoolchildren

Abstract

Background: Food and water are common exposure sources of arsenic and lead among children. Whereas dietary sources of these toxicants are fairly well-studied, the contribution of drinking water to toxicant exposures is not well characterized in many populations, particularly in the Global South.

Objective: To assess the extent to which consumption of household drinking water contributes to arsenic and lead exposure among Uruguayan schoolchildren with low-level exposure.

Methods: Children, aged 5-8 years, were enrolled into the Salud Ambiental Montevideo study during 2009-2013 from schools in Montevideo, Uruguay. Participants reported water intake as part of two 24-h dietary recalls. Concentrations of arsenic were measured in first morning void urine samples, and adjusted for urinary specific gravity. Lead concentrations were measured in venous blood samples. Drinking water samples were collected from participants' homes and toxicant concentrations measured. Data analyses involved a triangulation approach. First, multivariable linear regressions estimated the associations between toxicant exposure through drinking water, calculated for each child as the product of water intake and water toxicant concentration, and the respective toxicant biomarker concentrations among children with complete data on all variables (Sample A; n = 40). Second, regressions were repeated for participants with complete data on all variables except water intakes (Sample B; n = 195), after water intakes were imputed. Finally, models were constructed for participants of Sample B (n = 195) based on drinking water intakes assumed to be fixed at 25th, 50th, 75th percentile intakes of participants in sample A.

Results: Toxicant exposure via drinking water intake was low. The triangulation approach revealed no associations between toxicant exposure through household water intake and the respective toxicant biomarker concentrations.

Conclusion: Studies with larger samples and repeated measures are needed to confirm these findings. Nevertheless, it appears that at low water toxicant concentrations, typical water consumption is not a major contributor to children's exposure.

Keywords: Arsenic; Children; Drinking water; Lead; Uruguay.