Investigation of Microbial Ecology and Degradation Potential in Lead-Contaminated Soils of Plateau State Mining Communities

Artisanal gold mining in Plateau State, North Central Nigeria, has caused severe lead soil contamination in communities such as Yelwa and Barkin Ladi, with significant child health consequences, yet the microbial ecology of these contaminated soils and the degradation potential of resident microorganisms remain unstudied. This study investigates microbial community composition and heavy metal tolerance in lead-contaminated soils from artisanal mining communities in Plateau State. Soil samples from mining waste piles, processing areas, and adjacent residential soils were collected, with control soils from uncontaminated farmland. Total culturable bacteria, heavy metal-tolerant bacterial populations, and minimum inhibitory concentrations for lead were determined. 16S rRNA gene amplicon sequencing characterised community structure. Lead biosorption and bioprecipitation potential were evaluated for dominant resistant isolates. Microbial diversity was significantly reduced in high-lead soils, with Proteobacteria and Actinobacteria dominating resistant communities. Bacillus cereus, Lysinibacillus sphaericus, and Cupriavidus metallidurans were identified as lead-tolerant species with high biosorption capacity. Biosorption efficiencies ranged from 52 to 79 percent in batch experiments. 16S rRNA sequencing confirmed dysbiosis in heavily contaminated samples, with sulphate-reducing bacteria enrichment suggesting active lead precipitation pathways. The study provides the first microbial ecology dataset for Plateau State lead-contaminated mining soils and identifies candidate organisms for bioremediation trials. Keywords: lead contamination, microbial ecology, bioremediation, artisanal mining, Plateau State