On-site sanitation impacts on water resources near Taylors Halt, KwaZulu-Natal, South Africa.

Abstract

As many as 2.5 billion people worldwide lack basic sanitation, where every year millions suffer from diarrhoea, cholera and other related illnesses as a result. On-site sanitation is a practical and viable solution, but the growing number of on-site sanitation systems pose a risk of lateral movement of contaminants during intense rainfall and threaten precious water resources. The aim of the study was to determine the lateral movement of on-site sanitation contaminants in the near surface hillslope through-flow, from Pour-flush and Ventilated Improved Pit latrine systems. This was done by observing the nitrate, phosphate, ammonium, sulphate, chloride, calcium, magnesium, sodium and potassium electrical conductivity and Escherichia coli values in the near-surface hillslope through-flow at different study sites. The results indicate that the on-site sanitation systems periodically impact the near surface groundwater, where the maximum values for nitrate, phosphate and Escherichia coli were 1656.5 mg/l, 206.2 mg/l and 241920 MPN/100 ml, respectively. On numerous occasions, several of the hillslope through-flow samples exhibited values well above the drinking water limits defined by the WHO and SANS. The presence of a near surface semi-pervious layer, water table depth and soil texture had a significant impact on the movement of contaminants in the groundwater. The results of this study will contribute to the improvement of existing scientific knowledge, and the development of guidelines for on-site sanitation suited to rural and peri-urban areas in developing nations.