Estimates of Blood Lead Levels (BLLs) for Children in Coastal Madagascar: Accounting for Dietary Uptake of Lead (Pb)

Thousands of households in coastal Madagascar that employ pitcher-pump systems to provide water for domestic use may be at risk for harmful exposure to lead (Pb), which leaches from locally manufactured pump system components. The Integrated Exposure Uptake Biokinetic model (IEUBK) can predict blood lead levels (BLLs) in exposed children, thereby characterizing potential health risks. However, it is unclear if the existing methodology of the IEUBK accounts adequately for dietary Pb contributions from contaminated cooking water. Therefore, aims of this study are (1) to develop a method for modifying the IEUBK to account for contaminated cooking water, (2) to quantitatively estimate the importance of dietary Pb uptake (relative to other routes of Pb exposure) in coastal Madagascar, and (3) to estimate BLLs of children in that area, accounting for dietary uptake. Results show that if the Pb concentration in household drinking and cooking water is low (<= 4 mu g/L), Pb in cooking water is not a major route of exposure; predicted BLLs in children are low regardless of whether the dietary component is modified. However, the importance of dietary intake increases with water concentration: if the household aqueous Pb concentration increases from 4 to 24 mu g/L, corresponding to the 90th percentile concentration measured in a field campaign, then the estimated dietary contribution to total Pb uptake can exceed 50%. Based on median measured Pb concentrations (11 mu g/L), 7-14% of children in households using pitcher-pump systems in coastal Madagascar would present with BLLs > 5 mu g/dL (i.e., levels implicated in developmental health issues); however, this number could exceed 90% in households or communities where the water concentration is particularly high. An important conclusion is that the IEUBK should be modified when applied to a developing-world context, where preparation of a starch food staple like rice may present considerable Pb exposure; omitting dietary uptake in cooking water potentially ignores the dominant route of Pb exposure.