Heavy metal contamination and health risks in Katoro's artisanal gold mining soils, Tanzania
Year: 2025
Type: article
Abstract: This study assessed heavy metal contamination in surface soils from artisanal gold mining areas in Katoro, Tanzania, evaluating ecological and human health risks. Thirty-six soil samples were systematically collected from three mining villages (Bingwa, Isenye, and CCM) at varying distances ranging from 30 to 90 m from active mining pits alongside twelve control samples from a non-mining area for comparison purposes. Concentrations of Cr, Cu, Ni, Zn, Pb, and As in soil samples were analyzed using energy-dispersive X-ray fluorescence spectrometry (EDXRF). Results revealed severe contamination, with Cr (117–1255 mg/kg), Cu (81–104 mg/kg), and Ni (89–271 mg/kg) exceeding permissible limits. The geoaccumulation (Igeo) index indicated moderate to heavy contamination (Class II-III) for Cr, Cu and Ni. Meanwhile, the ecological risk assessment showed moderate risk (ERI = 154.41) across the study area highest being in Isenye village (ERI = 204.46). Health risk models identified ingestion as the primary exposure pathway, with hazard indices (HI) below 1, suggesting negligible non-carcinogenic risks. However, lifetime cancer risks for As (1.21×10⁻⁴) and Cr (3.59×10⁻³) surpassed acceptable thresholds (1×10⁻⁴), indicating significant carcinogenic concerns, particularly for children. These findings underscore the urgent need for remediation and stricter regulations to mitigate contamination from artisanal mining activities.
Source: Tanzania Journal of Science
Authors: Innocent J. Lugendo, Venance Mwesiga
Language: English
Topic: Heavy metals in environment
Subfield: Pollution
Field: Environmental Science
Domain: Physical Sciences
Open Access status: diamond
OpenAlex ID: W4415653307
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