Lead (Pb) Contamination of Self-Supply Groundwater Systems in Coastal Madagascar: Estimates of Blood Lead Levels (BLLs) in Children

Households in coastal Madagascar rely on locally manufactured pitcher-pump systems to provide water for drinking, cooking, and household use. These pumps typically include components made from lead (Pb). In a field study of 18 household pitcher pumps in the city of Tamatave, concentrations of Pb were frequently observed to exceed the World Health Organization (WHO) provisional guideline of 10 μg/L. Under first-draw conditions (after a pump had been inactive for 1 h), 67% of samples were in excess of 10 μg/L Pb, with a median concentration of 13 μg/L. Flushing the pump systems before collecting water resulted in a statistically significant (p < 0.0001) decrease in Pb concentrations: 35% of samples collected after flushing exceeded 10 μg/L, with a median concentration of 9 μg/L. We modeled the ingestion of Pb with the integrated exposure uptake biokinetic model (IEUBK) to predict blood lead levels (BLLs) in children, thereby characterizing potential health risks. We modified the IEUBK model to account for the use of contaminated water in preparation of the top three foods in the Malagasy diet (rice, corn, cassava). Results indicate that this route may contribute up to 60% of overall Pb uptake in children, and therefore we conclude that the IEUBK model should be modified when applied to a developing-world context. The modified IEUBK predicts that as high as 94% of children could experience elevated BLLs (> 5 µg/dL) in households or communities where the Pb concentration is at the high end of our field observations.