Geophysical Assessment of Vulnerability of Surficial Aquifer in the Oil Producing Localities and Riverine Areas in the Coastal Region of Akwa Ibom State, Southern Nigeria

Abstract

1D resistivity sounding survey was combined with geological and geohydrochemical information in order to examine the aquifer vulnerability. Ten Schlumberger soundings were executed along one profile on the basis of proximity to functional boreholes. Ten samples of groundwater from nearby boreholes were checked for concentrations of significant trace element in the laboratory. The resistivity and geohydrochemical information were employed to examine the level of protection and the associated possible risk of the groundwater repository in the mapped area. The interpreted overburden parameters (resistivities and thicknesses) of water repositories were deployed to determine the integrated electrical conductivities (IEC) and susceptibility of hydrogeological units to surface contaminations. Based on results, Eket and Onna on the southern part of Nsit Ubium have IEC which reflect medium to poor protection capacity based on slightly protected and vulnerable protective layers above the underlain groundwater within the approximate depth range of 15-30 m. Nsit Ubium, the northern zone of the survey area, has a wide range of resistivity which creates windows or vulnerable pathways for percolation of waste pollutants from the surface which flow at the deeper layer. However, layers within 15-25 m depth provide good protection to their underlying aquifer based on IEC which are >1  -1 . Hydrochemical parameters also show higher values that are beyond the 2006 World Health Organization (WHO) standards. The integration of resistivity data and the hydrochemical data showed that the dominant topmost cover layers of the study areas are grossly vulnerable due to drainable pores in the formation.

Assessment of spatial distrilbution of porosity and aquifer geohydraulic parameters in parts of the Tertiary – Quaternary hydrogeoresource of south-eastern Nigeria

“…The prominent human activities which have negative impact on the Niger Delta environment include industrial (hydrocarbon exploration and exploitation, noise pollution, gas flaring, oil spillage, waste dis-posal), removal of backshore vegetation, construction of barges and other coastal control works, dredging of river, agricultural (excessive and uncontrolled application of pesticides, herbicides and inorganic fertilizers) practices (George et al, 2013). Others human activates that degrade the region include municipal waste disposal, urbanisation and mining (Ezeigbo and Ezeanyim, 2006;George et al, 2017aGeorge et al, , 2017b. Consequently, environmental problems such as coastal and riverbank erosion, flooding, land degradation, loss of biodiversity, loss of soil fertility and deforestation are now predominant in the area (UNEP, 2011;Kadafa, 2012; include municipal waste disposal, urbanisation and mining (Ezeigbo and Ezeanyim, 2006;George et al, 2017aGeorge et al, , 2017b.…”

“…Others human activates that degrade the region include municipal waste disposal, urbanisation and mining (Ezeigbo and Ezeanyim, 2006;George et al, 2017aGeorge et al, , 2017b. Consequently, environmental problems such as coastal and riverbank erosion, flooding, land degradation, loss of biodiversity, loss of soil fertility and deforestation are now predominant in the area (UNEP, 2011;Kadafa, 2012; include municipal waste disposal, urbanisation and mining (Ezeigbo and Ezeanyim, 2006;George et al, 2017aGeorge et al, , 2017b. The water resources of the area which the settlers of the region used for their domestic, agricultural, industrial and social needs are now degraded by both natural and anthropogenic sources (UNEP, 2011, Saliha et al, 2017.…”

Geoelectrohydraulic investigation of the surficial aquifer units and corrosivity in parts of Uyo L. G. A., Akwa Ibom State, Southern Nigeria

“…It is the major source of drinking water and is useful in the agricultural and industrial sectors, and a good knowledge of the aquifer repositories is a concern for its sustainable and effective use (Edet and Worden 2009;Evans et al 2010;George et al 2015aGeorge et al , 2016aGeorge et al , 2017aObiora et al 2015). Since the aquifer in the coastal regions is shallow, residents drilling for potable groundwater do not care about getting geophysical information about the area before drilling.…”