The Relationship between Hydro-Climatic Variables and <em>E. coli</em> Concentrations in Surface and Drinking Water of the Kabul River Basin in Pakistan

Abstract

Microbial water contamination is a risk for human health, as it causes waterborne diseases like diarrhea. <em>E. coli</em> is a faecal indicator microorganism. Climate variables, such as temperature and precipitation, influence <em>E. coli</em> concentrations in surface and drinking water resources. We measure and statistically analyse <em>E. coli </em>concentrations in drinking and surface water in the Kabul River Basin. <em>E. coli</em> concentrations are very high in the basin. Drinking and bathing water standards are violated. Water temperature, surface air temperature, discharge and precipitation were positively correlated with <em>E. coli</em> concentrations. Precipitation induced runoff transports of <em>E. coli</em> from agricultural lands to Kabul River and high temperature coincides with high precipitation and discharge. A linear regression model was developed to assess the net effect of the climate variables on <em>E. coli</em> concentrations. We found that climate variables accounted for more than half of the observed variation in <em>E. coli</em> concentrations in surface (R² = 0.61) and drinking water (R² = 0.55). This study indicates that increased precipitation together with higher surface air temperature, as expected in this region with climate change, were significantly correlated with increased <em>E. coli</em> concentrations in the future. Waterborne pathogens are expected to respond similarly to hydro-climatic changes, indicating that disease outbreaks could well become more frequent and severe.