Groundwater Quality Assessment In Aka-Offot Industrial Layout, Uyo, Akwa Ibom State, Nigeria

Abstract

Groundwater quality assessment was carried out on water samples from five boreholes collected through simple random sampling method during wet and dry seasons within Aka-Offot Industrial Layout, Uyo and a non-industrialized area (control site). The aim was to assess their quality by determining their physico-chemical properties and heavy metals for comparison with the control site and the world’s threshold standards. Water samples were collected with polyethylene bottles that were initially rinsed with 10% hydrochloric acid then with sample water. Two samples were collected from each borehole. One was for physico-chemical properties determinations while the other one was for heavy metal analysis. HNO₂ was added in the samples for heavy metal analysis for preservation of the metals. The samples were stored in an ice-packed cooler kit to the laboratory for analysis. The results revealed that the temperature of the water was slightly above WHO standard but fell below FEPA standard; turbidity and electrical conductivity fell within the permissible limits. The water was acidic because the mean pH value was lower than the permissible limit; dissolved oxygen was significantly low while biological oxygen demand was higher than the permissible limit signifying high load of organisms and impurities in the water. The total dissolved solid, ammonium, nitrate and sulphate were below the permissible limits. The mean values of Fe, Pb, Zn, Cr and Co fell below the permissible limits. For Cd, it’s dry season mean value was a little above WHO permissible limit but fell below FEPA standard while the dry season mean value of Mn was above FEPA’s permissible limit but all of them fell within the WHO limit. However, industrial wastes disposed in this area have had adverse effects on the groundwater. Therefore, adequate waste management method is one of the recommendations prescribed for a healthy and sustainable environment.