Contaminants Evaluation As Indicators Of Water Quality In Ago-Iwoye, Southwestern, Nigeria

Abstract

The study evaluates some functional parameters of well water in a densely populated university town, Ago-Iwoye, South-western, Nigeria. Well water samples were collected at ten sites across the town. Analysis of the presence of Coliform count, Salmonella count, standard plate count, physicochemical properties (14 elements and 2 physical parameters) as indicators of water contaminants in the wells in the study area were carried out on the water samples. 40 % of the well samples were contaminated with coliform while 20% were contaminated with salmonella indicating the source of contamination (fecal contaminant). Further analysis revealed that most of the wells have their mineral values within the tolerant level according to WHO standard, however the two most toxic chemicals from the recommendations of WHO were identified in wells 2,3,5 and 10 with values exceeding tolerant level of 0.05 mg/l for lead and 2.56mg/l value for nitrate in well 2.Results confirm the presence of bacteria growth of such samples, highly dangerous to life. Also wells 2, 4, & 8 were contaminated with excess concentration of Iron (Fe) mineral which could make the water tasty and have bacteria growth while wells 1, 2, 3, & 7 have excess concentrations of Copper (Cu) mineral which could cause a stringent taste. Introduction Well water is the major source of water for the purpose of human activities (consumption inclusive), and agricultural sector in the rural area of Ago-Iwoye. Ago-Iwoye is geographically located on longitudes 3 degrees 50 minutes and 3 degrees 56 minutes East, and latitudes 6 degrees 55 minutes and 7 degrees North. Geologically, it is within the basement complex of Southwestern Nigeria, comprising the migmatites and porphhyroblastic gneiss. The wells are approximately between 5 to 55 m deep, even though waste products are disposed by septic tanks and the minimum distance required between septic tanks and wells should be about 30 m (Lamka et al., 1980), this was not so with the wells at the study area as some wells close to septic tanks are about 10-20 m away. Water, we know, is a solvent whose main sources are; rivers, springs, wells and other water bodies and once such water is available for drinking then it may serve as a route of exposure to contaminants (Cantor, 1997). The importance of well water, which is the main source of drinking water in the study area, is for the existence of human society (Agriculture sector and human consumption) and most importantly for body detoxification through drinking since more water in essence can build a stronger immune system. According to (Quinlan, 1990), well water is an important and integral part of the hydrological cycle, its availability then depends on the rainfall and recharge conditions. If a bacterial water quality problem is detected, it could be occurring in the water system, the well or less likely the aquifer (Wood et al., 2002). The quality of well water is getting severely affected because of the wide spread pollution of surface water. Besides, discharge of untreated wastewater through bores and leachate from unscientific disposal of solid waste also contaminates well water, thereby reducing the quality of fresh water resources. It has been shown that in the presence of any