Comparative Assessment of Water Quality Parameters and Microbial Loads in Selected Well Water as an Index of Pollution

Groundwater is an essential resource for drinking and its quality is extremely important to human health, monitoring it will offer tangible protection for man and other living creatures. This study assessed and compared water quality parameters and microbial loads in selected groundwater as an index of pollution in Iseyin, part of geopolitical zone in Oke-ogun areas of Oyo State. Water samples were collected from three different well water in Iseyin based on their nearness to dumpsites, hospital and area assumed to be clean. The physico-chemical parameters were examined using standard laboratory procedures. Heavy metal concentrations were analysed using spectrophotometry methods. Microbial loads of the water samples were examined by membrane filter and media were prepared following the manufacturer’s instructions. Pollution index of water samples were determined by Arithmetic Index (WQI) and Nemerow’s Pollution Index. The result showed highest turbidity values in January (A; 29.57±21.89, B; 132.17±0.29 Ntu and range of 1.77±0.15-75.33±0.58 Ntu across stations in the wet seasons. Biological Oxygen Demand values ranged from 3.60±0.00-28.43±36.52 mg/L and 4.57±0.58-14.57±0.06 mg/L across dry and wet months. Highest values of Electrical Conductivity and Phosphate across sampling stations were also recorded. Other Parameters were within the recommended limits of World Health Organization (WHO) and Nigeria Standard for Drinking Water Quality (NSDWQ). However, heavy metal concentrations revealed Lead as Below Detective Limits while its presence in some stations were higher than the limits. Zinc revealed highest values in Jan (16.17±0.15 mg/L) at station C, and May (8.80±0.10 mg/L) in station A. Copper and Iron were at peak in many stations both dry and wet months. Microbial loads revealed highest coliform and viable counts in many water samples examined. Water quality indices indicated high pollution status of the groundwater samples. The study concludes that majority of water samples examined were highly contaminated with highly suspended particles that resulted into high values of EC, nutrient influx, heavy metal contamination particularly those water samples collected near dumpsites and hospital as a result of anthropogenic impacts. This study recommends serious water treatment before consumption and regular monitoring of the water sources.