Health Risk Assessment of Trace Elements in Groundwater Around Marble Mine in Owa-Kajola, Southwestern Nigeria

This study was carried out to assess health risk of trace elements in groundwater around marble mine in Owa-Kajola, Southwestern Nigeria. Groundwater samples were collected from twenty (20) hand dug wells and analyzed for trace elements (Cd, Cr, Cu, Fe, Mn, Pb and Zn. The results show that concentrations of Cd (0.016 ppm) and Pb (0.20 ppm) are above recommended limits of WHO and NSDWQ which attributed to geogenic and anthropogenic sources. The average values of exposure dose in Fe and Zn are 8.898 mg/kg/day and 3.769 mg/kg/day respectively and above standard limits. In children, average Cd is 0.622 mg/kg/day which is < 1 while other trace elements are higher in values. The hazard quotient (HQ) and hazard index (HI) values in adults and children are < 1 and these show that groundwater in study area is low non-carcinogenic risk. The average values for chronic daily intake (CDI) are < 1 and groundwater is less risk. The average carcinogenic risk values computed for Cd (6E-05 to 2E-04), Cr (8E-04 to 3E-03) and Pb (5E-02 to 2E-01) exceeded the recommended values of 10E-6 and 10E-4 in both adults and children with health implications such as kidney disease, lung cancer among others. High concentrations of some trace elements in analyzed groundwater could be from geogenic and anthropogenic sources in study area. Regular monitoring of groundwater in study area is recommended.