Water Quality Assessment of Hand Dug Wells, Boreholes and Surface Water in Sobe, Edo State and Hand Dug Wells in Elegbeka, Ondo State, Nigeria

Abstract

Quality assessment of groundwater and surface water sources was done for twenty-five water samples in rural communities Sobe (15 samples) located in Owan West Local Government Area of Edo State and Elegbeka (10 samples) located in Ose Local Government Area of Ondo State. Shallow hand-dug wells and principal sources of water in these communities as boreholes are few and not accessible to all and sundry. Physicochemical and biological analyses of the twenty-five water samples were done under strict compliance with modern laboratory techniques to appraise the quality of water for domestic, agricultural and industrial purposes for both wet and dry season samples. Sampling was done in month of February (dry season) and September (wet) 2011 and the samples were also collected in duplicates. The pH reading of water obtained in Sobe dry season 5.30 to 6.94, Elegbeka dry season 6.08 to 7.60 and Sobe wet season 4.96 to 6.57 and Elegbeka wet season 5.32 to 7.15. The turbidity reading of water obtained in Sobe dry season 0.29 to 216 FAU, Elegbeka dry season 0.85 to 63.8 FAU, Sobe wet season 0.14 to 47.4 FAU and Elegbeka wet season 0.18-35.3 FAU. The TDS reading of water obtained in Sobe dry season 6.7 to 234.5 mg/l, Elegbeka dry season 26.8 to 582.9mg/l, Sobe wet season 26.8 to 1118 mg/l and Elegbeka wet season 87.1 to 1353mg/l. The electrical conductivity reading of water obtained in Sobe dry season 10.0 to 350 µscm, Elegbeka dry season 40.0-870.0 µscm, Sobe wet season 40 to 16780 µscm and Elegbeka wet season 130 to 2020 µscm. Analysis of heavy metals such as Lead, Zinc, Cadmium and Chromium, was also conducted. Results obtained from the analysis gives ranges of concentration of lead in samples from 0.1mg/l – 0.2mg/l. Chromium concentration ranges was minimum of 0.2mg/l to maximum of 3.7mg/l in well 1 dry season sample of Elegbeka. Cadmium concentration ranges from both Sobe and Elegbeka were not much, but when present were far above NAFDAC permissible limits. Results obtained from the analysis reveals that the groundwater is likely to be influenced by the geochemistry of the bedrock as well as anthropogenic activities such as indiscriminate refuse dumps which are particularly all over Elegbeka community. Mirco-organism such as total bacteria count and E.coli were recorded in samples. This can be attributed to infiltration of leachates from pit latrines and refuse dumps making the water unfit for human consumption but none-the-less suitable for irrigation purposes. Water table of the wells in Sobe and Elegbeka community were subject to seasonal yielded fluctuations and generally very low in the peak of the dry season. Concentrations of the heavy metals was also generally higher in the dry season than the wet season.