Trace elements contamination of soils around gold mine tailings dams at Obuasi, Ghana

Abstract

This study investigated the issue of tailings dams as a potential source of trace elements contamination
in soils at the Obuasi gold mine in Ghana. Soil samples taken from depths of up to 12 cm and within a radius of 400 m from the tailings dams (active and recommissioned), were analysed for As, Cu, Pb and
Zn using atomic absorption spectrometry. Average concentrations of As, Cu, Pb and Zn in soils around
the active tailings dams were respectively 581±130, 39.64 ± 3.02, 24.22 ± 2.62 and 72.64 ± 8.01 mg/kg.
Soils in the vicinity of the decommissioned tailings dam registered increased values - 1711 ± 172, 71.44
± 5.27, 38.67 ± 3.59 and 168.1 ± 36.2 mg/kg for As, Cu, Pb and Zn respectively. Both types of tailings dams impacted adjoining soils with greater concentrations of the trace elements when compared to undisturbed control soils. Arsenic was above the Netherlands intervention value of 55 mg/kg dry weight, even in control soils. The following trend of accumulation was observed in the soils: As>Zn>Cu>Pb. Improved tailings management strategies, among other factors, might have influenced the reduced
level of trace elements contamination at the active tailings dams’ site.