Determination of potential groundwater sites using geological and geophysical techniques in the Cross River State, southeastern Nigeria

Okereke, C.S.; Esu, E. O.; Edet, Aniekan

doi:10.1016/s0899-5362(98)00053-0

Cited by 53 publications

(21 citation statements)

References 3 publications

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“…The aquifer is composed of unconsolidated fine-medium-coarse-gravelly sand and gravel. The groundwater is unconfined, but the occurrence of clay of various thicknesses in places gives rise to a semiconfined condition and multiaquifer system (Okereke et al, 1998). Groundwater recharge is through precipitation and the surrounding Calabar and Great Kwa River.…”

Section: Geology and Hydrogeologymentioning

confidence: 99%

Concentrations of heavy metals and hydrocarbons in groundwater near petrol stations and mechanic workshops in Calabar metropolis, southeastern Nigeria

Nganje¹,

Edet²,

Ekwere³

2007

Environ. Geosci.

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A B S T R A C TGroundwater and soil samples from 16 locations near petrol stations (PS) and mechanic workshops (MW) around Calabar, Nigeria, were analyzed for heavy metals and hydrocarbons to determine their concentrations and assess the impact of the PS and MW on groundwater in the area. Results show that mean concentrations of arsenic, cadmium, chromium, copper, iron, mercury, manganese, nickel, lead, and zinc in groundwater are higher than the reference data (maximum admissible concentration, baseline value, and control site value). The mean concentration of total organic content in soil is low (4.03%), but the mean concentrations of total petroleum hydrocarbons (46.87 mg kg À 1 ) and naphthalene (340.00 mg g À 1 ) in the soil are high in comparison to the reference data. The mean concentrations of parameters in soil and groundwater are higher where PS and MW are located near each other (PS/MW). The mean total hydrocarbon content (0.66 mg L À 1 ) and total polycyclic aromatic hydrocarbon ( P PAH) (66.64 mg L À 1 ) in groundwater are higher than the maximum admissible concentration of 0.1 mg L À 1 and 0.2 mg L À 1 , respectively. The concentration of PAH compounds with mean concentrations greater than 1 mg L À 1 are of the order phenanthrene > anthracene > fluorene > benzo(b)fluoranthenebenzo(k)fluoranthene pyrene > naphthalene. The ratios of phenanthrene/anthracene, fluoranthene/pyrene, and benzo(a)anthracene/ chrysene and factor analysis indicate several sources for the PAH. The most important sources include anthropogenic (petrogenic, pyrolytic) and natural.

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Section: Geology and Hydrogeologymentioning

confidence: 99%

Concentrations of heavy metals and hydrocarbons in groundwater near petrol stations and mechanic workshops in Calabar metropolis, southeastern Nigeria

Nganje¹,

Edet²,

Ekwere³

2007

Environ. Geosci.

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“…This condition implies that the underlying aquifer repository is vulnerable to surface contamination due to the seemingly low values of the aquifer longitudinal conductance which will be far less than unity. In some VES values, the vertical extent of the gravelly materials is transitional at variable depths by fissures, weathering, joints, fractures, doming, baking and lineaments which impact the sand-clay intra-lithologic sequence secondary porosity [25][26][27]. The development of these structures, which are known to be pathways for the circulation of water in the previously impervious hardened materials, is an indicator of the post-depositional processes that the intra-lithologic argillaceous materials have undergone [24,27,28] .Gowd [27] has also discussed the importance of these secondary structures on the ground water yield in a compacted limestone environment.…”

Section: Resultsmentioning

confidence: 99%

A survey of the repository of groundwater potential and distribution using geoelectrical resistivity method in Itu Local Government Area (L.G.A), Akwa Ibom State, southern Nigeria

2013

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Vertical electrical sounding (VES), employing a Schlumberger electrode configuration, was used to investigate the sediments and aquifer repositories in Itu Local Government Area of Akwa Ibom state, southern Nigeria. This was done in sixteen (16) locations/communities with the maximum current electrode spread ranging between 800-1000m. The field data were interpreted using forward and iterative least square inversion modeling, which gives a resolution with 3-5 geoelectric layers. The observed frequencies in curve types include 31.25% of AKH, 18.8% of AAK and HK and 6.25% of K, QHK, AKH, KA and KHQ, respectively. These sets of curves show a wide range of variabilities in resistivities between and within the layers penetrated by current. The presence of K and H curve types in the study area indicates the alteration of the geomaterials with limited hydrologic significance to the prolific groundwater repository. A correlation of the constrained nearby borehole lithology logs with the VES results shows that the layers were all sandy formations (fine and well sorted sands to gravelly sands or medium to coarse-grained sands as described by nearby lithology logs) with some wide ranges of electrical resistivity values and thicknesses caused by electrostratigraphic inhomogeneity. The geologic topsoil (motley topsoil) is generally porous and permeable and as such the longitudinal conductance (S) values for the covering/protective layer is generally less than unity of Siemens (S < 1Ω −1 ), the value considered for efficient protection of the underlying aquifers by the topmost and overlying layer. The spatial orientations and the leveling patterns of the most economically viable potential groundwater repository within the maximum current electrode separations has been delineated in 2-D and 3-D contoured maps. The estimated depth range for the desired groundwater repository is 32.6-113.1m and its average depth value is 74.30m. The thickness of this layer ranges from 27.9-103m while its average depth has been evaluated to be 63.02m. Also, its resistivity range and average value have been estimated to be 507-5612Ωm and 3365.125Ωm

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“…In the study area, few of the published works have been on location of aquifers and borehole sitting using electrical resistivity (Edet, 1993;Okereke et al, 1998;Okon-Umoren, 1999) as well as delineation of Coastal Plain Sands into upper and lower aquifers (Edet & Okereke, 2002;Amah & Esu, 2008). Edet (2004) on the basis of CALOD index concluded that the upper aquifer was more vulnerable to surface contaminants than the lower aquifer.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of Groundwater Potentials of the Calabar Coastal Aquifers

Amah¹,

Ugbaja²,

Esu³

2012

JGG

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This article presents the results of groundwater site evaluation scheme and quality assessment of coastal aquifers in Calabar, South-eastern Nigeria based on ground water potential index (GWPI) scale, developed for this study. The GWPI consists of ten input parameters, namely: lithofacies (L), aquifer thickness (b), transmissivity (T), storativity (S), specific capacity (SC), static water level (SWL), formation resistivity (FR), chloride (Cl) contents, total dissolved solids (TDS) and Escherichia coli (E-coli). The groundwater potential index (GWPI) is computed as the sum of the products of weights and ratings assigned to each of the input parameters. The GWPI index varying between 20 and 60, is divided into three classes: high (> 40), medium (30-40), and low (< 30). The GWPI index, is then used to demarcate the study area into three hydrogeologic ground water potential zones. These are:(i) Northern zone 1 (transitional, low GWPI) (ii) Central zone 2 (coastal plain sands, high GWPI) (iii) Southern zone 3 (coastal alluvium, medium GWPI).The central zone 2 has the highest GWPI rating. The implication of this rating is that the aquifers in the central and southern zones 2 and 3 are more prolific water bearing than the transitional zone 1 that lies between the Coastal Plain Sands and the argillaceous sediments of the Calabar Flank. This is in agreement with the mean specific capacity (SC) and transmissivity ( Lithofacies, saturated thickness of the aquifer, static water level, transmissivity and storativity are the most important parameters which influence ground water availability in the study area. The GWPI results further reveal that E-coli (3-50 counts/100ml), chloride (Cl -) (2.5-21.0 mg/l) and static water level (SWL) (2.3-28.7 m) remain the most significant parameters that contribute to groundwater pollution particularly in the southern zone of the study area. In the near future, water quality in aquifer will be affected due to poor management of human waste-disposal/salt water intrusion, thereby limiting the availability of potable water for domestic and industrial uses.

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Determination of potential groundwater sites using geological and geophysical techniques in the Cross River State, southeastern Nigeria

Cited by 53 publications

References 3 publications

Concentrations of heavy metals and hydrocarbons in groundwater near petrol stations and mechanic workshops in Calabar metropolis, southeastern Nigeria

Concentrations of heavy metals and hydrocarbons in groundwater near petrol stations and mechanic workshops in Calabar metropolis, southeastern Nigeria

A survey of the repository of groundwater potential and distribution using geoelectrical resistivity method in Itu Local Government Area (L.G.A), Akwa Ibom State, southern Nigeria

Evaluation of Groundwater Potentials of the Calabar Coastal Aquifers

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