Assessment of heavy metal pollution at the urban Maputsoe dumpsite, Lesotho and the associated ecological risks

Heavy metals are recognized as critical environmental pollutants due to their toxicity, persistence, non-biodegradability, bioaccumulation potential, and limited metabolic elimination in humans. Despite Maputsoe’s industrial activity and proximity to residential and school areas, no prior studies have evaluated heavy metal contamination at its solid waste dumpsite. This study investigated the concentrations of six heavy metals (Cu, Fe, Mn, Pb, Cr, and Cd) in dumpsite soils using Atomic Absorption Spectrophotometry. Geochemical parameters were also assessed, and pollution severity was evaluated using five indices: enrichment factor (EF), geo-accumulation index (Igeo), ecological risk factor (Eir), contamination factor (Cf), and degree of contamination (Cd). The mean metal concentrations (mg/kg) followed the order: Fe (373 ± 66.97) > Mn (41.98 ± 2.95) > Cu (31.58 ± 3.91) > Pb (29.59 ± 11.54) > Cr (7.56 ± 1.81) > Cd (3.05 ± 0.20). Pb and Cd exceeded background levels at specific locations and were identified as the primary contaminants. Ecological risk index (Eir) values classified Cd as the most hazardous metal, posing considerable risk at S1, moderate at S2, and very high risk at S3. All other metals exhibited low ecological risk across sites. Pearson’s correlation analysis revealed strong associations (p < 0.01) among Mn, Pb, and Cd, suggesting a shared anthropogenic source, likely textile industry waste. A separate correlation between Fe and Cr implies a different origin. Based on these findings, immediate remediation is recommended, along with continuous monitoring to support informed environmental management and safeguard public health in the Leribe District.