Health Risk Assessment of Groundwater from Selected Areas of Ijebu North, Ogun State, Nigeria

Safe drinking water is essential to all forms of life and poor water quality is a critical public health concern in many rural areas. This study examined the water qualities and health risk indices of the groundwater samples from selected areas of Ijebu-North Local Government Area of Ogun State, Nigeria. The samples were evaluated for physico-chemical, total metal load, microbial load, targeted health hazard quotient (HQ), health hazard indices (HI), water quality indices (WQI), heavy metal evaluation indices (HMEI), heavy metal toxicity indices (HMTI), heavy metal pollution indices (HMPI) and the environmental water quality index (EWQI) parameters. The results obtained indicate variations in the parameters assessed which were mainly within the World Health Organization recommended limits for drinking water. The hardness, nitrate, the total coliform count and confirmatory fecal coliform counts, iron and cadmium contents were higher than recommended limits. Using the WQI ratings, 25% of the groundwater samples were 'excellent' and 'suitable' for drinking while 75% were unsuitable for drinking. HEI of the groundwater varied from 'medium' to 'high' class while HMPI varied from low to medium and HMTI was in a high class for all the water samples. EWQI values placed Awa and Ijebu Igbo borehole water samples as the best water samples and Oru well water as the worst water sample. Cluster analyses show that Awa and Ijebu Igbo boreholes clustered together and have similar qualities distinct from other locations. Proper treatment of the water samples before use as they can pose health hazards is recommended.