Risk assessment of the anthropogenic activities (quarrying) and heavy metal profile in mining environment.

Abstract

The need to generate internal revenue by most individuals and government in Nigeria has led to the establishment of quarries in different parts of Ebonyi state of Nigeria. This study was aimed at determining the risk associated with the heavy metal burden in the state. Soil samples from the quarrying environments designated as MS1, MS2, and MS3 were analyzed for the metal profile using inductively coupled plasma optical emission spectrometry (ICP-OES). The result showed that the mean concentration of metals which is a representation of the whole sites showed a higher concentration of Ca (40.065 ± 1.011ppm), Mg (12.450 ± 8.815ppm), K (16.631 ± 14.670ppm), and Mn (19.539 ± 3.225ppm) while Na (1.326 ± 0.117ppm) was low. The heavy metal profile showed Pb (0.120 ± 0.027ppm), Fe (27.718 ± 1.523ppm), Zn (2.227 ± 0.570ppm), Cu (6.267 ± 1.402ppm), Ni (1.856 ± 0.472ppm), Mo (1.758 ± 0.258ppm), Cd (0.023 ± 0.006ppm), Cr (0.037 ± 0.011ppm), etc. Hg was found to be below detectable limit while the Cs was not radioactive. The mean values were found to be lower than the permissible limit of each metal. The pollution index (PI) was calculated for the different sites, and the result reveals that MS3 (0.0426) had a higher PI when compared to MS1 (0.0341) and MS2 (0.0317). Therefore, the PI of the sites showed MS3 > MS1 > MS2. These results showed that the environment is still as safe as PI < 1. The geoaccumulation index also showed a safe environment since its values were less than 0 which means that the environment is practically uncontaminated. Other risk determining parameters showed that the three locations were still within a safe level. Although the results of the study have shown a safe environment, it is still necessary to keep close monitoring of the heavy metal profile of the environment, since these metals can bioaccumulate in living tissues with time.