Spatial Distribution and Variability of Groundwater Quality in State Capital and Contiguous Local Government Areas under Urbanization Expansion

Abstract

The objective was to investigate groundwater quality in boreholes located in Uyo urbanized state capital, and four contiguous Local Government Areas (LGAs) of Ibiono Ibom, Ikot Ekpene, Itu and Nsit Ubium, under Coastal Plain Sands(CPS) formation, for spatial and temporal variability of groundwater quality and compatibility with Nigerian Standards for Drinking Water Quality (NSDWQ)indicating prospects of pollution diffusion due to urbanization spread. Standard examination methods were employed as well as morphological and bacteriological counts. Data on waterquality properties were statistically analyzed using SPSS software version 17 for descriptive statistics, covariance (CV), ANOVA and for percentage compatibility computations. Data on Uyo samples showed the lowest values while Ibiono showed median values; heavy metals showed highest spatial variability at CV ≥ 35%. Significant difference (P < 0.1) was observed in temporal variability between 2013 and 1993 values (20 years interval). The suggested causes were: spread of pollution by construction ruts, stagnant polluted water, and vehicular traffic commuting urban-rural areas, open uncontrolled dumping of various solid/organic wastes, insanitary handling of water and wastewater and low standard of borehole drilling in rural-urban fringe adjusting to suburbanization. Compatibility with NSDWQ varied per parameter and location but were generally within acceptable standards; however, iron, lead and cadmium in the contiguous LGAs were higher in concentrations and should be periodically monitored. Bacterial counts, especially coliform count exceeded standard MPN and called for sanitation intensification.