Use of I-geo and enrichment factor in assessing soil pollution status around auto-mechanic workshop clusters in Yenagoa, Bayelsa State, Nigeria

Abstract

Heavy metals could be induced into new environments either naturally or anthropogenically. Anthropogenic input of heavy metals into soils has been on the increase in recent years in various towns and cities as it is a major means through which heavy metals that were not indigenous to a given geographical area could be introduced into new environments. The need to ascertain the exact anthropogenic activities responsible for discharge of heavy metals into man's environment can never be over-emphasized. Therefore, this work focused on ascertaining the current pollution status and contributory source of heavy metals around soils of auto-mechanic workshop clusters in Yenagoa Metropolis, Bayelsa State, Nigeria. Three upper soil layers (0 to 15 cm, 15 to 30 cm and 30 to 45 cm) were sampled over three distant extremes (0 meter, 50 meters and 100 meters) and analyzed. Values of i-geo showed that Zn (2.23) showed moderate to highly polluted geogenically while Pb (0.76), Cu (0.79), Cd (0.77), Co (0.63), Cr (0.65), Ni (0.83), Hg (0.48), Mn (0.94) and Fe (-0.13) showed unpolluted to moderately polluted geogenically around soils of auto-mechanic workshop clusters in the Yenagoa Metropolis. Enrichment factor has shown that Zn (1.47) was not delivered through anthropogenic but geogenic sources while Pb (11.54), Cu (10.18), Cd (13.54), Co (4.02), Cr (15.35), Ni (13.48), Hg (8.89) and Mn (4.16) were respectively delivered anthropogenically. Fe (1.00) was the normalizer. The progressive contamination scenario observed in soils of the auto-mechanic workshop clusters in this work were mainly attributable to anthropogenic activities arising from unprofessional ways artisans adopted in disposal of heavy metal-bearing wastes onto soils of the study area. This calls for serious concern as progressive deterioration of soil quality induces negative health and environmental effects which has tendencies for affecting living organisms, on the long run.