Assessment of groundwater quality near a dumpsite and evaluation of human health risk in southeast Maseru, Lesotho

Abstract Inadequate management of municipal solid waste (MSW) is a global environmental concern for human health and ecosystems. In Lesotho, open dumping is the oldest method of solid waste disposal that threatens nearby water bodies, especially groundwater. There is under-presentation of monitoring data from the Ts’osane dumpsite, and this study intended to address the gap. The study investigated groundwater quality and level of non-carcinogenic health hazard for residents who consume the groundwater. Chemical oxygen demand (COD), chlorides (Cl), copper (Cu), electrical conductivity (EC), iron (Fe), lead (Pb) and pH) were analysed from 30 samples for five private boreholes within the 900 m radius from the dumpsite, following the American Public Health Association (APHA) standard methods. Data analysis entailed descriptive analysis, and correlation coefficient established relationships amongst the parameters. Hazard Quotient (HQ) and Hazard Index (HI) were used to assess communities’ risk. The results were as follows: Cl (191–288.7 mg/L), COD (54–82.25 mg/L), Fe (0.18–1.22 mg/L) and Pb (0.05–0.08 mg/L) and were in the order Pb > Fe > COD > Cl. The mean of 1173 µS/cm for EC was slightly below the permissible threshold of 1500 µS/cm. Cl, COD, Fe and Pb exceeded the World Health Organisation (WHO) limit for drinking water. The dumpsite may have influenced groundwater quality, however, health risk assessment revealed that HQ and HI were below 1, indicating a low likelihood of adverse health effects. The study recommends utilisation of anti-seepage systems to avert further seepage of pollutants into groundwater.