PHYSICO-CHEMICAL AND BIOLOGICAL ANALYSIS OF HAND DUG WELLS IN ISOKO NORTH LOCAL GOVERNMENT AREA OF DELTA STATE, NIGERIA

Abstract

The study is aimed at assessing the quality of water from shallow hand-dug wells in Isoko North Local Government Area of Delta State from the month of September to November, 2015. The people in the study area highly depend on this source of water for drinking and domestic activities. Water samples were collected from nine sites (W1, W2, W3, W4, W5, W6, W7, W8& W9) from the study area. These samples were examined for trace heavy metals(Mn, Fe, Zn and Cd) using Atomic Absorption Spectrophotometer (AAS), bacteriological contamination (Total coliform and E.coli) and some physicochemical parameters. The results obtained were studied and compared with World Health Organization (2011) standard. The pH values obtained ranged from 4.22 to 6.08 showing that the water samples were slightly acidic. COD, DO and BOD values obtained all exceeded the permissible limit of WHO standard showing that the water from the study area may cause detrimental effect to human life. Phosphates and sulphates contents were higher than the WHO(2011) permissible limit. The microbiological analysis showed that the total coliform and E.coli count recorded values were not within WHO permissible limit which is an indication of fecal contamination. All other physic-chemical parameters (temperature, turbidity, electrical conductivity, total hardness, nitrate and chloride) were within the acceptable WHO(2011) Permissible limits. The water samples from the wells have higher level of heavy metals: Mn, Fe, Zn and Cd were found to be above the permissible limits of WHO (2011) specifications of 0.05 mg/l, 0.03mg/l, 0.05mg/l and 0.05 mg/l for Mn, Fe, Zn, and Cd respectively. The results obtained showed that the water from the study area were contaminated making the water unfit for drinking. Contamination of this water source may have been caused by closeness of water source to pit latrine, domestic refuse dumps, stagnant water, bad sewage system and other human activities. Consequently, these ground water sources in this study require treatment before they will be good for human consumption.