Browsing by Author "Njoku, Adora Olivia"
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Item Application of artificial neural network and multi‑linear regression techniques in groundwater quality and health risk assessment around Egbema, Southeastern Nigeria(Published by Journal of Environmental Earth Sciences, 2023-01-24) Akakuru, Obinna Chigoziem; Adakwa, Chidi Bello; Ikoro, Diugo Okereke; Eyankware, Moses Oghenenyoreme; Opara, Alexander Iheanyi; Njoku, Adora Olivia; Iheme, Kenneth Obinna; Usman, AyatuThis paper examined the efficiency of artificial neural network (ANN) and multivariate linear regression (MLR) models in the prediction of groundwater quality parameters such as ecological risk index (ERI), pollution load index (PLI), metal pollution index (MPI), Nemerow pollution index (NPI), and geoaccumulation index (Igeo). 40 groundwater samples were collected systematically and analyzed for mainly heavy metals. Results revealed that adopting measured parameters is effective in modeling the parameters with high level of accuracy. Contamination factor results reveal that Ni, Zn, Pb, Cd, and Cu have relatively low values < 1 within the region while the Iron values ranged from low contamination to very high contamination (> 6). PLI, MPI, and ERI results indicated low pollution. NPI results indicated that the majority of the samples were heavily polluted. Quantification of Contamination results revealed that most of the sample's quality was geogenically influenced. Igeo results revealed that most of the samples had extreme pollution. The health risk assessment results revealed that children are substantially prone to more health risk more than adults. The ANN and MLR models showed a high effective tendency in the prediction of ERI, PLI, MPI, NPI and Igeo. Principal component analysis results showed appreciable variable loadings while the correlation matrix results reveal that there exists weak and positive correlation amongst elements. Based on the outcome of this study, this research recommends the use of ANN and MLR models in the prediction of groundwater quality parameters as they yielded positive, reliable, acceptable, and appropriate accuracy performances.Item Electro‑geohydraulic estimation of shallow aquifer characteristics of Njaba and environs, Southeastern Nigeria(Saudi Society for Geosciences and Springer Nature Switzerland, 2023) Akakuru, Obinna Chigoziem; Onyeanwuna, Uzochi Bright; Opara, Alexander Iheanyichukwu; Iheme, Kenneth Obinna; Njoku, Adora Olivia; Amadi, Chinyere. C.; Akaolisa, Casmir Zander2023 Abstract The study investigated the use of electro-geophysical method as an alternative to pumping test method in the estimation of geo-hydraulic characteristics of shallow aquifers in Njaba and environs, Southeastern Nigeria. This was done to ascertain the aquifer potentials of the study area. Twenty-three geo-electric resistivity soundings were acquired using ABEM Terrameter SAS-4000 and Schlumberger configuration with maximum half-current electrode spacing of 500 m. Geo-electric layers were determined using FORTRAN 2D Resistivity Software. The results indicate an undulating topography, with elevations ranging from 361 to 1336.9ft. Spread 5 m, 20 m, 50 m, 100 m, 150 m, 200 m, 250 m, 300 m, 400 m, and 500 m were probed, which gave their corresponding resistivity values at different depth slices. Results showed a fairly increasingreducing- increasing trend of resistivity values. An averaged high resistivity value can be traced to the presence of the sand lithology of the Benin Formation in the region. Aquifer depth of 79.2 to 115 m was observed in the study area, showing a semi-deep aquifer system. Aquifer thickness of 23.4 to 48.5 m was observed in the studies, with a mean value of 37.71 m. Aquifer resistivity ranges from 28,700 to 990Ωm, indicating clean sand and sand with little clay admixtures, respectively. Average longitudinal conductance (in Ω−1) of 0.00611693 and transverse resistance of 407,178.1739 was recorded in the study area. Hydraulic conductivity (in m/day), as obtained from a new model, showed a high value of 27.90068 and a low value of 0.0852, an indicator of fairly clean sand. Transmissivity ( m2/day), from a new model developed for the study area, ranges from 430.0877 to 23.552. The storativity value ranges from 0.0001515 to 0.00113139, indicating a confined aquifer, while average aquifer diffusivity of 1,398,057.749 was recorded. Altogether, aquifer vulnerability and hydro-geochemical studies of the environment are recommended, to ascertain the protective capacity of the aquifer from the surface pollutants and the quality of water in the study area, respectively.