Effects of High Temperature and Heavy Precipitation on Drinking Water Quality and Child Hand Contamination Levels in Rural Kenya

Abstract

Climate change may impact human health through the influence of weather on environmental transmission of diarrhea. Previous studies have found that high temperatures and heavy precipitation are associated with increased diarrhea prevalence, but the underlying causal mechanisms have not been tested and validated. We linked measurements of Escherichia coli in source water (n = 1673), stored drinking water (n = 9692), and hand rinses from children <2 years old (n = 2634) with publicly available gridded temperature and precipitation data (at ≤0.2 degree spatial resolution and daily temporal resolution) by the GPS coordinates and date of sample collection. Measurements were collected over a 3-year period across a 2500 km2 area in rural Kenya. In drinking water sources, high 7-day temperature was associated with a 0.16 increase in log10 E. coli levels (p < 0.001, 95% CI: 0.07, 0.24), while heavy 7-day total precipitation was associated with a 0.29 increase in log10 E. coli levels (p < 0.001, 95% CI: 0.13, 0.44). In household stored drinking water, heavy 7-day precipitation was associated with a 0.079 increase in log10 E. coli levels (p = 0.042, 95% CI: 0.07, 0.24). Heavy precipitation did not increase E. coli levels among respondents who treated their water, suggesting that water treatment can mitigate effects on water quality. On child hands, high 7-day temperature was associated with a 0.39 decrease in log10 E. coli levels (p < 0.001, 95% CI: −0.52, −0.27). Our findings provide insight on how climate change could impact environmental transmission of bacterial pathogens in Kenya. We suggest water treatment is especially important after heavy precipitation (particularly when preceded by dry periods) and high temperatures.

Effects of weather extremes on fecal contamination along pathogen transmission pathways in rural Bangladeshi households

“…A previous study in Bangladesh found that safe storage of tubewell water in a container with a narrow mouth, tight-fitting lid and spigot significantly improved stored water quality and reduced diarrhea 34 . In a recent study in Kenya, heavy rainfall and extreme temperature were associated with increased E. coli in source water from boreholes, springs, and wells while heavy rainfall but not extreme temperature was associated with increased E. coli in stored drinking water 14 . In the same study, heavy rainfall did not increase stored water contamination among households that treated their water 14 .…”

“…In a recent study in Kenya, heavy rainfall and extreme temperature were associated with increased E. coli in source water from boreholes, springs, and wells while heavy rainfall but not extreme temperature was associated with increased E. coli in stored drinking water 14 . In the same study, heavy rainfall did not increase stored water contamination among households that treated their water 14 . Our findings suggest that treatment and safe storage of drinking water is especially important following extreme rainfall and temperature.…”

“…Others have hypothesized that children may have cleaner hands during higher rainfall and temperatures because they may spend less time playing outside and/or have more water available for handwashing 14,36 . Children in our study were young (85% ≤3 years, 30% ≤1 year).…”

“…Data on weather effects on other fecal-oral transmission pathways are scarce. A single study to date has found lower E. coli counts on children's hands following increased temperature but not heavy rainfall in Kenya 14 .…”

Implications of Dynamic Interactions between Meteorological Patterns and Surface Water Quality on Environmental Health&amp;#8212;A Case Study of the Nairobi River

“…Temperature plays a critical role in shaping water quality parameters, exerting a significant influence on aquatic ecosystems and human health. Several studies have emphasized the intricate relationship between temperature and water quality indicators, highlighting the importance of understanding these dynamics in the context of climate change (Osman et al, 2024;Powers et al, 2023; Surface Water: The Importance of the Water Temperature, 2024; Water Science School, 2024).…”