Characterisation of Hydro-Geochemical Processes Influencing Groundwater Quality in Rural Areas: A Case Study of Soutpansberg Region, Limpopo Province, South Africa

Abstract

Groundwater is often the main or only source of fresh water supply in arid to semi-arid rural areas owing to decreasing rainfall patterns, reduced availability of surface water and socioeconomic activities. It is important to understand the hydro-geochemical processes influencing groundwater quality for improved management and sustainability of resources and to improve rural livelihoods. To understand the hydro-geochemical process influencing the hydro-geochemistry of the Soutpansberg region, this study assessed groundwater quality data from 12 boreholes and 2 geothermal springs collected between 1995 and 2017. This study indicated that the majority of the samples were classified as fresh groundwater dominated by Ca-HCO3 and mixed Ca-Mg-Cl types. Gibbs diagrams, Pearson correlations, bivariate plots and saturation indexes suggested that rock dominance processes, such as weathering of silicates, dissolution of carbonates and halite minerals and ion exchange processes, were the main hydro-geochemical processes influencing the groundwater quality in the Soutpansberg region. The high concentration of F− in the geothermal spring was attributed to the dissolution of fluorite mineral. Point source anthropogenic inputs from fertilisers were attributed to the high concentration of NO3− in the groundwater. This study recommends that research outputs should be used to influence and support policy change and groundwater allocation in arid to semi-arid rural environments for improved management of resources and livelihoods. This study further recommends that suitable deflouridation and denitrification techniques be applied to improve the quality of groundwater for drinking purposes.

Water quality, geochemistry and human health risk of groundwater in the Vyeboom region, Limpopo province, South Africa

“…The temporal changes in the origin of the recharged water and hydrological human factors may also cause periodic changes in groundwater quality 5 . Thus, in order to ensure the quality of groundwater, previous research has recommended that scientific investigations should be used as a decision support system for policy adoption and groundwater designation in rural arid to semi-arid environments 7 .…”

“…Collins Chabane municipality covers an area of approximately 5003 km 2 with an estimated population of 347,975. Research has shown that in the Soutpansberg region (which includes Vhembe district) factors such as weathering of silicates, ion exchange processes as well as dissolution of carbonates and halite minerals are hydro-geochemical processes which influence the quality of groundwater 7 . The main land use activities are residential settlements, agriculture and natural forests.…”