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Clasen, T.

Publications and source records attributed to Clasen, T..

2 recordsLinked to original sources
bioRxiv2020

Microbiological water quality of Managed Aquifer Recharge systems in the salinity-prone southwest coastal Bangladesh

Managed aquifer recharge (MAR), a hydro-geological intervention designed to dilute groundwater salinity, pumps pond water treated through a slow sand filter into the underground aquifers. We evaluated the microbiological safety of the resulting MAR water at sites from three districts in southwest coastal Bangladesh. We collected monthly paired pond-MAR water samples from July 2016-June 2017 and enumerated fecal coliforms and E. coli using the IDEXX quanti-tray technique, by the most probable number (MPN) method. We used WHO risk categories for microbiological quality; no risk (<1 MPN), low risk (1-10 MPN) and moderate to high risk (>10 MPN per 100 mL water). We estimated the difference in mean log10 MPN in pond and MAR water using linear mixed effect models with random intercepts and cluster adjusted robust standard error. Almost all pond water samples (292/299, 98%) had moderate- to high-risk level (>10 MPN) fecal coliforms and E. coli (283/299, 95%). In contrast, 81% (242/300) of MAR water samples had no or low risk level fecal coliforms (0-10 MPN), of which 60% (179/300) had no fecal coliforms. We detected no or low risk level E. coli in 94% (283/300) of MAR water samples of these 80% (240/300) had no E. coli. MAR samples had lower mean log10 MPN fecal coliforms (-2.37; 95% CI: -2.56, -2.19) and E. coli (-2.26; 95% CI: - 2.43, -2.09) than pond water; microbial reductions remained consistent during the wet (May-October) and dry seasons. MAR-systems provided water with reduced fecal indicator bacteria compared to infiltered pond water.

microbiology↗
bioRxiv2019

Can individual and integrated water, sanitation, and handwashing interventions reduce fecal contamination in the household environment? Evidence from the WASH Benefits cluster-randomized trial in rural Kenya

Combined water, sanitation, and handwashing (WSH) interventions have the potential to reduce fecal pathogens along more transmission pathways than single interventions alone. We measured Escherichia coli levels in 3909 drinking water samples, 2691 child hand rinses, and 2422 toy ball rinses collected from households enrolled in a two-year cluster-randomized controlled trial evaluating single and combined WSH interventions. Water treatment alone reduced E. coli in drinking water, while a combined WSH intervention improved water quality by the same magnitude but did not affect levels of fecal indicator bacteria on child hands or toy balls. The failure of the WSH interventions to reduce E. coli along important child exposure pathways is consistent with the lack of a protective effect from the interventions on child diarrhea or child growth during the trial. Our results have important implications for WSH program design; the sanitation and handwashing interventions implemented in this trial should not be expected to reduce child exposure to fecal contamination in other similar settings.

microbiology↗