The Dangerous Couple: Illegal Mining and Water Pollution—A Case Study in Fena River in the Ashanti Region of Ghana

Abstract

The threat posed by illegal mining to the quality of water resources in Ghana has become a major public concern due to the closing down of some water treatment plants in the country. This study aimed to investigate heavy metal pollution in Fena River due to the illegal mining activities. The study was based on 72 samples from six sampling points for a period of 12 months (January–December). Six heavy metals such as lead (Pb), cadmium (Cd), copper (Cu), mercury (Hg), iron (Fe), and zinc (Zn) in water were investigated from Fena River in the Amansie Central District in the Ashanti Region of Ghana. The ranges of the heavy metals in water were BDL–1.041, 0.01–0.703, BDL–0.24, 0.17–16.43, 0.46–1.02, and BDL for Pb, Cd, Cu, Fe, Zn, and Hg. Three metals exceeded the safe drinking water guidelines making water generally unsafe for drinking and domestic purposes. According to Nemerow’s pollution index results, three metals, namely, Cd, Pb, and Fe, were the principal metal pollutants in the study area, whereas Hg, Cu, and Zn were found not to contribute to the pollution effect. However, of the polluting metals, only Cd polluted all the six sampling sites, whereas Pb polluted five out of the six sampling sites. The most striking of the results is the absence of mercury in all the sites studied. The findings from the water quality index confirm that only two of the sites recorded marginal water quality, whereas the remaining four sites recorded poor water quality. The high levels of heavy metals polluting water and the deteriorating water quality are due to the illegal mining activities occurring within and around Fena River.