Unveiling the hidden threat to human health: groundwater contamination in the largest mining enclave of southwestern Ghana

This study evaluates the chemistry of groundwater, significant pollutants, pollution sources, and related health issues in the Tarkwa Nsuaem Municipality (TNM) in Ghana, which has the highest concentration of mining firms in West Africa and is dominated by artisanal and small-scale mining activities. To accomplish this, previous studies from the TNM were synthesized, and the quality of the groundwater in the municipality was discussed using previously published research from different areas of the municipality. The findings of this review revealed that bacteriological contamination of groundwater in the municipality is high, especially in Abekoase, Samahu Quarters, Aboso, Tarkwa Railway Quarters, Jerusalem, Nkamponase, GAG Mile 7 No. 2, Tarkwa Community Center and Teberebie Roadside. This is because of the unhygienic conditions surrounding the groundwater sources in these areas. In addition, hand-dug wells in the Akoon and Benso communities had high concentrations of nitrate (NO₃⁻). The NO₃⁻ contamination is largely due to agricultural run-off and the leaching of mining explosive residues. High iron (Fe) levels in groundwater have mainly been reported in the Nsuta manganese mining enclave. Simpa, Tarkwa Senior High School, Aboso, Nsuta, and Nsuaem are the areas most affected by groundwater manganese (Mn) contamination. The concentration of lead (Pb) in Nkamponase, Tarkwa Community Center, and UMaT is slightly higher than the guideline value of the World Health Organization (WHO). Nearly all the settlements in the TNM have mercury (Hg) concentrations in groundwater that are higher than the WHO guideline value. Weathering, dissolution, hydromorphic dispersion of Fe, Mn, and Pb-bearing ore minerals, acid mine drainage, and artisanal and small-scale mining operations in the municipality are the causes of heavy metal mobilization in groundwater. People are at risk of water-borne diseases and various types of cancer due to groundwater contamination; thus, urgent measures must be taken by stakeholders to curtail the menace.