Search

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 µg/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 µg/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 µg/L), 7–14% of children in households using pitcher-pump systems in coastal Madagascar would present with BLLs > 5 µg/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.

Fifty biological sand filters (BSFs) housed in 70-L plastic containers were built and installed in the West Pokot County of Kenya. Half of the BSFs were installed in June 2010; the remainder were installed in June 2012. BSF performance was analyzed during June 2012 and 2015. Performance indicators included the removal of turbidity and fecal and total coliforms. In 2012, 17 of the original 25 BSFs installed were operational, and their performance was evaluated. In 2015, 15 of the BSFs were operational. BSF performance during 2015 showed an average fecal coliform removal of 98.9%. The most common reasons provided to explain why the BSF installed was no longer in use included the family moved and the BSF was too heavy to carry, and the effluent pipe broke. Relative affluence was observed using the Progress out of Poverty Index (PPI)™. With an increase in elevation, we noted a decrease in PPI. The average PPI for homesteads with operation BSFs was 10 points higher than homes where the BSFs were in disrepair. An assay to estimate Escherichia coli presence and concentration was modified, and the results were compared with more traditional field enumeration methods. The field assay used a five-compartment bag to quantify the most probable number (MPN) of E. coli to provide a low-tech option to field workers in developing country to test the viability of drinking water sources. We used a Hach medium, varying from that prescribed by Aquagenx. Results from using the modified method compared well with the more traditional field assay.

Thousands of 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 this study, concentrations of Pb in water were monitored at 18 household pitcher pumps in the city of Tamatave over three sampling campaigns. Concentrations of Pb frequently exceeded the World Health Organization's provisional guideline for drinking water of 10 μg/L. Under first-draw conditions (i.e., after a pump had been inactive for 1 h), 67% of samples analyzed were in excess of 10 μg/L Pb, with a median concentration of 13 μg/L. However, flushing the pump systems before collecting water resulted in a statistically significant (p0.0001) decrease in Pb concentrations: 35% of samples collected after flushing exceeded 10 μg/L, with a median concentration of 9 μg/L. Based on measured Pb concentrations, a biokinetic model estimates that anywhere from 15% to 70% of children living in households with pitcher pumps may be at risk for elevated blood lead levels (5 μg/dL). Measured Pb concentrations in water were not correlated at statistically significant levels with pump-system age, well depth, system manufacturer, or season of sample collection; only the contact time (i.e., flushed or first-draw condition) was observed to correlate significantly with Pb concentrations. In two of the 18 systems, Pb valve weights were replaced with iron, which decreased the observed Pb concentrations in the water by 57-89% in one pump and by 89-96% in the other. Both systems produced samples exclusively below 10 μg/L after substitution. Therefore, relatively straightforward operational changes on the part of the pump-system manufacturers and pump users might reduce Pb exposure, thereby helping to ensure the continued sustainability of pitcher pumps in Madagascar.