ABSTRACT

Heavy metals applies to the group of metals and metalloids with atomic density greater than 4g/cm’ They occur naturally in rocks, but most of their occurrences originate from anthropogenic sources. Heavy metals may contaminate the surface water and groundwater resulting in deterioration of drinking and irrigation water. Water samples of Iyinna spring was studied from January to June 2017 in three stations and compared with national and international standards to evaluate its heavy metal content as well as assess its potential human health risk. The water samples were collected from below the surface of water using a 1 litre sampler and were transferred to a prewashed plastic bottle where they were acidified with Nitric acid. The concentrations of eight heavy metals (Manganese, Copper, Lead, Iron, Zinc, Cadmium, Chromium and Nickel) were determined by atomic absorption spectroscopy (AAS). The range of metal concentrations recorded were as follows: Manganese (0.06 - 0.52 mg/l), Copper (0.02 - 0.15 mg/l), Lead (0.01 - 0.72 mg/l), Iron (1.12 - 5.10 mg/ 1), Zinc (0.21 - 0.90 mg/l), Cadmium (0.01 - 0.43 mg/l), Chromium (0.01 - 0.24 mg/l) and Nickel (0.005 - 0.25 mg/l). Some of the values recorded such as Fe, Cd, Cr, and Pb exceeded national and international standards. Oneway analysis of variance (ANOVA) test showed that there was no significant difference in the metals in the stations. Correlation analysis showed positive and significant relationship among the metals. The human health risk assessment showed that Hazard Quotient of Fe, Cd, Cr and Pb were all greater than unity and pose potential health risk for both adults and children. The Hazard Index of the water for the 3 stations was of high risk. This study showed that the metals were of geogenic source rather than anthropogenic which makes it more difficult to manage.