Environmental Technology & Innovation 22 (2021) 101486 Contents lists available at ScienceDirect Environmental Technology & Innovation journal homepage: www.elsevier.com/locate/eti Evaluation of underground water quality for drinking and irrigation purposes in New Valley Governorate, Egypt Ahmed A. Abdelhafez a,b,∗ , Mohamed H.H. Abbas c , Mona H.M. Kenawy d , Ahmed Noureldeen e , Hadeer Darwish f , Ashraf M.G. Ewis g , Mahdy H. Hamed a a Department of Soils and Water, Faculty of Agriculture, New Valley University, Egypt b National Committee of Soil Science, Academy of Scientific Research and Technology, Egypt c Department of Soils and Water, Faculty of Agriculture, Benha University, Egypt d Soils, Water and Environment Research Institute (SEWRI), Agricultural Research Center (ARC), Egypt e Department of Biology, College of Sciences, Taif University, P.O. Box 11099, Taif 21944, Saudi Arabia f Department of Biotechnology, College of Sciences, Taif University, P.O. Box 11099, Taif 21944, Saudi Arabia g Department of Soils and Water, Faculty of Technology and Development, Zagazig University, Egypt article info Article history: Received 27 September 2020 Received in revised form 29 January 2021 Accepted 5 March 2021 Available online 9 March 2021 Keywords: Underground water Irrigation Drinking Potentially toxic elements (PTEs) abstract Underground water is the main and probably the only source of drinking and irrigation in New Valley Governorate (Egypt). To assess water suitability for such purposes, 30 well-water samples (80–1300m depth) were collected from three oases i.e., El-Kharga, Baris and El-Dakhla. The pH values of these waters ranged from 6.5 to 7.88. SO 2− 4 was the dominant anion in such waters while Ca 2+ was the dominant cation. Concentrations of both ions (SO 2− 4 and Ca 2+ ) exceeded the maximum allowable limits for drinking and irrigation purposes. Although sodium adsorption ratio (SAR) values did not exceed ‘‘10’’ in all waters samples; however, Mg-hazards and low infiltration rate might threaten the suitability of water for irrigation in many locations. Concentrations of Zn, Mn, Cu, Pb, Cd, As and Se were below the maximum allowable concentrations suggested by FAO for irrigation water. On the other hand, Fe was the only potentially toxic element (PTE) whose concentrations exceeded the permissible levels of WHO regulations for drinking water. According to the principal component analysis (PCA), these metals were originated from natural (Fe, Mn, Zn and Cu) and anthropogenic (As, Pb, Cd and Se) sources. Their existence represents potential chronic threats to children, particularly Fe, Mn, Pb and As. Moreover, the majority of water samples were within the moderate grade of irrigation quality index while exhibited low grades for the drinking quality index. Accordingly, more attention should be paid towards improving the quality of underground water in New Valley governorate for either drinking or irrigation purposes. © 2021 Elsevier B.V. All rights reserved. 1. Introduction Water is the source of life for all living organisms and human being. On earth, there exists about 37 Mkm 3 of fresh water available (Sarath Prasanth et al., 2012); however, there is a substantial need for more water resources; especially, in developing countries to meet the growing demands for water (Abdelhafez et al., 2020). In particular, water scarcity problem is notable in countries of North Africa which suffer from limited rainfall (Steyl and Dennis, 2010). They depend mostly on underground water from aquifers to satisfy their needs (Abouelmagd et al., 2012). This hidden water resource ∗ Corresponding author at: Department of Soils and Water, Faculty of Agriculture, New Valley University, Egypt. E-mail address: ahmed.aziz@aun.edu.eg (A.A. Abdelhafez). https://doi.org/10.1016/j.eti.2021.101486 2352-1864/© 2021 Elsevier B.V. All rights reserved.