GROUNDWATER QUALITY ASSESSMENT USING BOREHOLE WATER SAMPLES IN UTE-UREKPOKI COMMUNITY IN BENIN CITY, SOUTH WESTERN NIGERIA

ABSTRACT

Groundwater samples were collected from Ute-Urekpoki Community of Benin City in Edo State, Nigeria, whose major source of water supply is via groundwater, with the view of accessing their quality for consumption. A total of twelve (12) borehole samples were obtained from various points in the study area and analysed for physico-chemical contaminants using standard methods. This analysis was done to confirm the potability of the water which is being consumed by the residents. Results of the analysis of the groundwater in the study area showed that some of the water samples met the minimum requirements of the Nigeria Standard for Drinking Water Quality (NSDWQ) and World Health Organization (WHO) for sulphate, chloride and Total Dissolved Solids (TDS). Generally, heavy metals exceeded the standard for almost all the samples. However, 75% of the water samples were slightly acidic as they fell below the NSDWQ range limit of 6.5-8.5. Furthermore, all the water samples exceeded the NSDWQ limit of 400mg/L for hardness. Cadmium was also found to exceed the NSDWQ limit of 0.003mg/L in all water samples while 50% of the water samples slightly exceeded the 0.5mg/L limit for Iron. The presence of cadmium in most of the water samples suggests that there is high risk in consuming water from these boreholes. Cadmium is a very toxic metal which bio-accumulates in the body. This leads to neurological problems as well as organ failure which ultimately lead to death. Similar experiments conducted by other students in the past five years suggest that the problem of cadmium is persistent. Due to the life threatening effect of cadmium on humans, it is generally concluded that water from the study area should not be consumed without treatment. This can be done using reverse osmosis.