Artisanal and small-scale mining effects on freshwater resources: a case study of the Oda River in the Ashanti Region of Ghana

Abstract Artisanal and small-scale mining (ASM) have rendered freshwater resources across the globe unsafe for consumption, posing health risks. The study assessed 15 water quality parameters using standardised water examination protocols. Twenty-four water samples were analysed from the upstream, midstream, and downstream of the Oda River, and the results were compared with the Ghana Standards Authority (GSA) and the World Health Organisation (WHO) water quality benchmarks. The concentrations of electrical conductivity (EC), total dissolved solids (TDS), pH, lead (Pb), cadmium (Cd), mercury (Hg), arsenic (As), fluoride (F), copper (Cu), and cyanide (CN) were within permissible limits. However, the turbidity concentrations are 694, 1755, and 1658 NTU (> 5.0), the total suspended solids (TSS) concentrations are 438, 1380, and 1360 mg/L (> 0), iron (Fe) concentrations are 9.0, 34.0, and 20.0 mg/L (> 0.3 mg/L), faecal coliform concentrations are 180, 145, and 180 MPN/100 mL, and Escherichia coli ( E. coli ) concentrations are 83, 125, and 235 MPN/100 mL (> 0 MPN/100 mL) exceeding the recommended standards. The Principal Component Analysis (CPA) and Hierarchical Cluster Analysis (HCA) suggest low ASM impact in the upstream compared to the midstream and downstream. The Comprehensive Pollution Index (CPI) values of 172.62 in the upstream, 468.68 in the midstream, and 401.31 in the downstream (> 2.0) indicate severe pollution of the Oda River. The study provides invaluable information on the effects of ASM activities on freshwater quality, ecosystems, and public health. The study concludes that ASM activities in freshwater basins obstruct SDG-6 attainment in Ghana and should be banned or properly regulated.