TITLE:
Heavy Metal Contamination Assessment in Soils and Surface Waters around an Abandoned Mine Site in Jiko Village, North-Central Nigeria
AUTHORS:
Hammed Rasheed, Abdullahi Suleiman, Waheed Gbenga Akande
KEYWORDS:
Heavy Metals, Abandoned Mine Site, Soil and Water Contamination, Artisanal and Small-Scale Mining (ASM), North-Central Nigeria
JOURNAL NAME:
Journal of Geoscience and Environment Protection,
Vol.14 No.5,
May
28,
2026
ABSTRACT: Six soil and eight water samples were collected from the abandoned mine site at Jiko village, near Minna Metropolis, Northcentral Nigeria, to determine the concentrations and contamination status of selected heavy metals (Pb, Zn, Cu, Ni, Cr, Fe, Mn, As, and Cd). The study evaluates contamination levels using established geochemical indices and assesses associated environmental implications. Mean concentrations in soils are Pb (77.09 ppm), Zn (68.82 ppm), Cu (44.08 ppm), Ni (78.23 ppm), Cr (183.84 ppm), Fe (41,466.34 ppm), Mn (525.69 ppm), and As (0.071 ppm), with the order of abundance: Fe > Mn > Cr > Ni > Pb > Zn > Cu > As. In water, mean concentrations are Pb (0.78 ppm), Zn (0.55 ppm), Cu (0.25 ppm), Ni (0.53 ppm), Cr and Cd (below detection limit), Fe (19.61 ppm), Mn (3.53 ppm), and As (0.060 ppm), following the order: Fe > Mn > Pb > Zn > Ni > Cu > As. The concentrations of Pb, Zn, Cu, Ni, Cr, and Fe in soils exceed average crustal abundance values, indicating enrichment relative to natural background levels. In water samples, Pb, Ni, Mn, Fe, and As exceed the permissible limits set by the Nigerian Standard for Drinking Water Quality (NSDWQ) and World Health Organization guidelines, indicating deterioration of water quality. Contamination indices reveal varying degrees of metal enrichment. The geo-accumulation index (Igeo) indicates that all analysed metals, except As, fall within the extremely contaminated category. The contamination factor (CF) shows considerable contamination for Pb, Cu, Ni, and Cr, moderate contamination for Zn, Fe, and Mn, and low contamination for As. Similarly, the enrichment factor (EF) indicates moderate enrichment for Pb, Cu, Ni, and Cr, while other metals fall within deficiency to minimal enrichment. These results demonstrate that mining activities have modified the geochemical baseline of the study area. Although Pb appears to be predominantly geogenic, its enrichment suggests additional contributions from artisanal mining activities. Field observations further indicate significant ecological degradation, including loss of farmland and vegetation, proliferation of open mining pits, and contamination of surface waters. The elevated concentrations of heavy metals, particularly Pb, Ni, Mn, Fe, and As in water, highlight potential environmental and public health risks. This study provides baseline data on contamination around the abandoned Jiko mine site and demonstrates that abandoned mine environments remain active sources of pollution long after mining activities have ceased. Continuous environmental monitoring and appropriate remediation strategies are therefore required to mitigate long-term ecological and public health impacts.