Escalating asm impacts on wetlands in umzingwane catchment

Artisanal and small-scale gold mining (ASM) within Zimbabwe’s Umzingwane catchment has intensified, resulting in pronounced degradation of wetland and fluvial ecosystems. This study employs spatial analysis from Land-sat land cover data, systematic field groundtruthing, and comprehensive physicochemical assessment of surface water and sediment to quantify ASM-induced environmental perturbations. Field investigations documented extensive channel incision, riparian zone disruption, and rudimentary artisanal recovery operations. Analytical results from six Ncema River sampling sites revealed chromium and chloride concentrations exceeding WHO potable water standards, with moderate enrichment of iron, manganese, sulfate, and phosphate, while mercury, cyanide, and arsenic were undetectable. Sediment profiles exhibited elevated iron, manganese and sulfate peaks consistent with active sulphide mineral oxidation processes. Spatial distribution patterns of contamination correlate an increase in ASM pit density since 2022, as delineated by satellite imagery. Policy analysis indicates fragmented institutional governance, archaic legislative frameworks, and deficient enforcement mechanisms constraining effective wetland and riverine protection. The integrated spatial, geochemical, and regulatory datasets reveal an escalating socio- ecological disturbance jeopardizing water security, agricultural productivity, and regional biodiversity. Immediate implementation of protective wetland buffer zones, statutory legislation reform emphasizing wetland conservation, and targeted ecosystem restoration focusing on sediment stabilization and riparian revegetation are imperative to mitigate irreversible environmental degradation.