Assessment of the impact of pit latrines on groundwater contamination in hopley settlement, Harare, Zimbabwe

Abstract

A study was conducted to assess the water quality of the groundwater sources and possible impacts of pit latrines on the groundwater for selected boreholes and wells. The City of Harare’s peri-urban settlement of Hopley predominantly uses pit latrines for excreta disposal. This puts groundwater at risk to contamination thereby threatening human health. Pit latrine density around groundwater points was assessed using a Geographical Information System (GIS). The pit latrine density ranged from 0 to 5 latrines in a 15 m radius to 3–63 latrines in a 100 m radius. From the analysis of the water samples, it was observed that on average, only 63% and 48% of samples met drinking water quality standards set by the World Health Organization guidelines and Standards Association of Zimbabwe limits. Principal component analysis (PCA) showed that only three components had an eigenvalue of over 1 that explained 76.9% of the total cumulative variance of the observed variable. From the PCA, key parameters in groundwater contamination were nitrates, electrical conductivity, chlorides, ammonia, and thermotolerant coliforms. The spatial variation of the selected water quality parameters suggests that water points at the lowest end of the settlement had the poorest water quality. The point-of-use treatment is recommended for wells.