Soils Quality Assessment in Kambele Gold Mining Area using Multivariate Statistical Analysis Approach

Abstract

This study assesses soil quality in the Kambele gold mining area (Eastern Cameroon) through integrated physico-chemical characterization, pollution index calculation, multivariate statistical analysis, and spatial mapping. Thirty surface soil samples (0-5 cm depth) were collected in June 2021 using systematic random sampling across the 30 km² study area. Physico-chemical parameters (pH, electrical conductivity, organic matter, moisture content) and heavy metal concentrations (Cr, Ni, Cu, Zn, Pb, Fe, Mn, As) were determined using XRF spectrometry (Skyray EDX POCKET III). Results reveal acidic soils (pH 5.12-6.22) with elevated electrical conductivity (96-416 μS/cm) and variable organic matter (0.30-1.42%). Heavy metal concentrations show significant contamination exceeding WHO guidelines for Pb (max 114 ppm), Cu (485 ppm), Ni (655 ppm), As (60 ppm), and Fe (121,611 ppm). Comprehensive pollution assessment using 15 indices (EF, Igeo, CF, PI, PLI, PIVector, MEC, CSI, Cdeg, Nemerow, Potential Ecological Risk, ExF, mCd) indicates moderate to extreme contamination, with Cu and Ni showing the highest enrichment. Principal Component Analysis (PCA) explains 72.83% of total variance, identifying three contamination sources : natural pedogeochemical background (PC1 : 49.93%), mining-related inputs (PC2: 22.90%), and mixed anthropogenic sources (PC3: 12.07%). Spatial kriging maps reveal heterogeneous contamination patterns with identified hotspots at Djengou washing station (E28) and site E8. Human health risk assessment indicates non-carcinogenic hazard indices exceeding USEPA thresholds for children (HI > 1) at multiple locations, primarily driven by As, Pb, and Cu exposure. These findings underscore the urgent need for targeted remediation strategies, including phytoremediation for moderately contaminated areas, soil amendments for pH adjustment, and containment measures for severe hotspots. This study provides the first comprehensive environmental baseline for Kambele, supporting evidence-based policy interventions and community health protection measures.