Spatial distribution and human health risk assessment of heavy metals in groundwater of Kolo- Creek and Environs, Eastern Niger Delta, Nigeria

This study investigated the distribution of heavy metals and human health risk assessment of them in the groundwater of Kolo Creek and environs, Niger Delta, Nigeria. Groundwater samples were collected from ten geo-referenced borehole points drilled to depths of 6 m. An Atomic Absorption Spectrophotometer (AAS) was utilised to ascertain the pollutant concentrations in the conserved samples. The average mean concentrations of the heavy metals (Cu = 0.43 mg/l, Zn =0.97 mg/l), (Cr, Cd, Hg, and Al not detected) in this study area for the two seasons were below international recommended limits except Pb = 0.019 mg/l and Fe = 35.57 mg/l which are above the international recommended limits of 0.01 mg/l and 0.3 mg/l respectively. The HI average (non-carcinogenic risk) value (1.561) for adults in all the locations is greater than 1, suggestive of likely health problems. The average HI value for children in all the locations is also greater than 1 (3.698), three times the value of adults also suggestive of greater health problems due to presence of the metallic contaminants in the children compared to the adults. The average CR (carcinogenic risk) value for Pb in adults and children in all locations exceeded (> 10−6) suggesting the possibility of cancer risk due to the intake of contaminated groundwater. Therefore, the results show that the children are at greater risk of cancer threefold more than the adults.