Trace elements in groundwater near an abandoned mine tailings dam and health risk assessment (NE Zimbabwe)

Abstract

Groundwater from shallow hand-dug wells at an abandoned gold mine tailings dam was characterised for selected physicochemical parameters during dry and wet seasons of 2018 and 2019. Health risk exposure of the local population (adults and children) through ingestion and dermal exposure was assessed. Groundwater quality parameters were lower than international drinking water quality guidelines (p < 0.05). The parameters
were significantly influenced by season of the year (As, Cl⁻, SO₄²⁻), nature (As, Cd, Cl⁻, Fe, NO₃−, SO₄²⁻), depth (Cd, Cl⁻, Fe, Ni, SO₄²⁻) and direction of the well (Cu, Cl⁻, Fe, NO₃−, Pb, SO₄²⁻) (p < 0.05) relative to the tailings dam. Groundwater did not pose non-carcinogenic risk due to studied trace elements. However, arsenic had the potential to cause medium to high cancer risk to the local population. We propose re-vegetation of the tailings dam, diversion of surface tailings drainage to a containment pond and the provision of continuous piped water supplies.