@misc{Ijioma, author = {Ijioma, Uche Dickson}, title = {Delineating the impact of urbanization on the hydrochemistry and quality of groundwater wells in Aba, Nigeria}, series = {Journal of Contaminant Hydrology}, volume = {Vol. 240}, journal = {Journal of Contaminant Hydrology}, issn = {0169-7722}, doi = {10.1016/j.jconhyd.2021.103792}, pages = {1 -- 13}, abstract = {Groundwater samples from 61 randomly selected tube-wells in densely residential (DR) and sparse residential (SR) parts of Aba, Nigeria were analysed to elucidate the influence of urban land-use on the quality and characterize the hydrochemistry of the groundwater. Twelve water quality indicators: temperature, pH, EC, and TDS (physicochemical), as well as HCO3, Cl, SO4, NO3, Na, K, Ca, and Mg (major ions) were analysed for each well. The results of the analyses were grouped based on the influence of land-use on the wells. The descriptive statistics, Piper, Chadha's, and bivariate scattered plots, as well as index of base ion-exchange, and Friedman nonparametric statistical test were used to delineate and ascertain the significance of the urban impact on the quality of the groundwater wells. The results showed that the groundwater pH is acidic (3.7-5.6), and the mineralization low, with TDS ranging between 6.5 mg/l - 365 mg/l. The statistical mean and standard deviation (±S.D) of the remaining quality indicators were found within the limits set by WHO in all the wells. The Piper and Chadha's plots revealed four dominant water-types with spatial differentiation in the area. Though there are several mixed water-types in the SR area, the Na-HCO3 water-type is dominant and represents the background hydrochemistry of the groundwater in the area. Whereas, Mg, Ca-Cl, water-types predominates in the DR wells. Other dominant water-types found between the SR and DR areas are Na-Cl and Ca-HCO3 types. The rapid compositional change and local alteration in the hydrochemistry of the groundwater were impacted by some identified urban land-use practices, which introduce additional major ions in the groundwater solution. The mixed water-types found in the SR wells were influenced by factors such as the direction of flow and mixing of the groundwater reservoirs impacted by the hydrochemistry of the DR groundwater, which were upstream to the SR wells. The results of indicators such as EC, TDS, Cl, and NO3, when compared showed observable local deterioration moving from wells in the SR to wells in the DR area. This was supported by the Friedman statistical test which revealed statistical significance of some urban practices on the quality of the groundwater. These results highlight the current quality status and harmonize the reports of previous studies which have characterized the hydrochemistry of the groundwater in the study area.}, language = {en} } @misc{IjiomaWendlandHerd, author = {Ijioma, Uche Dickson and Wendland, Frank and Herd, Rainer}, title = {Characterizing groundwater vulnerability in developing urban settings using DRASTIC-LuPa approach: A case study of Aba City, Nigeria}, series = {Academic Journals, African Journal of Environmental Science and Technology}, volume = {Vol. 15}, journal = {Academic Journals, African Journal of Environmental Science and Technology}, number = {12}, issn = {1996-0786}, doi = {10.5897/AJEST2021.3068}, pages = {540 -- 559}, abstract = {The impact of certain unregulated land-use activities harms the quality of water resources and reduces the sufficiency of drinking water in many developing countries. This study aimed to capture the impact of such activities and evaluate the specific groundwater vulnerability using a modified DRASTIC approach. The DRASTIC-LuPa was proposed and implemented for Aba City, Nigeria by incorporating land-use and the impact of pumping layers to the "intrinsic" DRASTIC parameters. The results of the analysis revealed that the area classified as "low" was 15 and 79.1\% as "medium" and 5.9\% as "high" vulnerability classes for the DRASTIC. Whereas for the DRASTIC-LuPa model 3.2\% for "low", 54.3\% for "medium", 41.8\% for "high" and 0.7\% for "very high" were found. The transitions in the vulnerability classes of areas displaying "high" and "very high" found in the DRASTIC-LuPa model represent the impact of urban hotspots observed in the area. This result implies that groundwater protection measures should be implemented in the area designated with "low" and "medium" vulnerability classes and used for abstracting clean water for drinking purposes. The proposed model enhances the predictability and guarantees better transferability of the approach in urban settings with similar urban trends.}, language = {en} }