Assessment of the multilevel correlations of the pollution indicators and lithological vulnerabilities in a passive limestone mining and cement producing environment

Abstract

This study presents the assessment of the air, soil, and water quality within the residential communities around two passive limestone mining/cement factories. The associations between the pollutants were tested across the media, within each medium, between the layers, and between two groups of the communities. The mean values for the PM1.0, PM2.5, and PM10 were 65.8 µgm−3, 50.1, and 73.7, respectively, in the air; for the Mn, Fe, Cu, Zn, Cr, K-40, U-238, and Th-232 were 0.433 g/kg, 8.950, 0.005, 0.054, 0.104, 161.57 Bq. kg−1, 61.10, and 15.85, respectively, in the topsoil; 0.365 g/kg, 8.259, 0.004, 0.029, 0.057, 71.84 Bq. kg−1, 16.37, 4.66, respectively, in the subsoil; and for the Mn, Fe, and Zn were 0.190, 1.499, and 0.256 mg/l, respectively, in the water. The PM10, Fe, and K-40 were the most abundant pollutants. The Co and Mn, Zn and Cu, Fe and Cu, the absorbed dose rate (ADR) and K-40, and ADR and U-238 correlated significantly. Though the Ibese group was more polluted than the Ewekoro group, the generally low levels of the pollutions were confirmatory of the earlier suspicions of the mining/production activities. The 2nd lithological layer at 0.5 to 1.9 m depths or the 3rd lithological layer at 1.1 to 7.69 m depths for the Ibese group and the 1st layer at the surface or the 2nd layer at 0.5 m depth for the Ewekoro group are protective layers for the groundwater that must not be exploited, given the three classes of groundwater vulnerability indices observed in the area.