Assessment of Heavy Metal Exposure and Cancer Risks for Communities Proximal to Gubi Dam Agricultural Area, Bauchi State, Nigeria

This study assessed the levels of some heavy metals (Cr, Mn, Fe, Cu, Ni, Cd, Hg, As, Pb) that were detected using Atomic Absorption Spectroscopy (AAS). Soil samples were collected at different depths (0-5, 5-10, 10-15cm) using a spiral Auger from five different agricultural locations (S1 – S5) around Gubi Dam, Bauchi State. The Concentration of those selected heavy metals in the soil samples was below the maximum recommended limits. Also, the carcinogenic health risk of heavy metals (Cr, Ni, As, Pb) and noncarcinogenic health risk of (Cr, Mn, Cu, Ni, Cd, Hg, As, Pb) in fifteen (15) soil samples collected at different depth of 0 – 5cm, 5 – 10cm and 10 – 15cm from Gubi Dam agricultural locations. The assessment was carried out using three different pathways: ingestion, dermal contact, and inhalation for children and adults with respect to average ages of 15 years and 70 years, respectively. In comparison, the result revealed that cancer risk (CR) levels of Cr Ni and Pb were found to be within the safer limit of 1.00E-06 – 1.00E-04, except As (1.14E-04mg/kgd-1, 1.52E-04mg/kgd-1, 1.03E-04mg/kgd-1) in adult through oral ingestion at sampling locations S1, S2, and S4 respectively, which exceeded the threshold limit; hence the population around the study area are possibly at a verge of CRs induced by As. Similarly, the study further revealed the CR levels in adults are greater than those for children, while the levels of the contact risk factors revealed in the order of ingestion > Dermal > Inhalation. Also, the noncarcinogenic health risk assessment with respect to Hazard Quotient (HQ) and Hazard Index (HI) revealed that the HQ values of all the heavy metals were found to be lower than the threshold limit of 1mg/kgd-1 with the exception of Cd (3.62E+00mg/kgd-1) in children through injection at S1 sampling location recorded a higher value above the standard limit. Likewise, the HI results were also within the accepted limit, except Cd (6.39E+00mg/kg) in soil at sampling point S1 recorded a higher value of above the safe limit. Therefore, findings from HQ and HI show that the populace around the study area might result in potential health risks concerning Cd.