Hydrochemical and Quality Assessment of Groundwater Resources in Al-Madinah City, Western Saudi Arabia

Abstract

Fifty-four groundwater samples were collected from Hamra Alasad in Al-Madinah City. The chemical and microbial characteristics of the samples were analyzed and compared with their respective standards. The results revealed that 90.7% of the samples showed higher amounts of NO3. However, 59.3% of the samples were found unfit for irrigation purposes due to a high salinity hazard. Most of the groundwater samples were highly saline, yet no sodicity hazards were anticipated as predicted by sodium adsorption ratio (SAR). Generally, the soluble cations and anions, dissolved salts, boron, and NO3− exceeded the maximum permissible limits for drinking water in most of the samples; however, Pb, Cd, As, Zn, Cu, Ni, Co, Fe, Mn, and Cr were within the permissible limits. Furthermore, 42.6%, 24.1%, 18.5%, 14.8%, 1.9%, and 37.0% of the samples were infected by a total coliforms group, fecal coliform, Escherichia coli, Staphylococcus sp., Salmonella sp., and Shigilla sp., respectively. The water quality index revealed that 3.7% of the samples were good for drinking (class II), and 9.3% were very poor (class IV). The remaining samples were unfit for drinking (class V) due to high salinity and/or microbial contamination. Durov and Piper diagrams revealed that the majority of water samples were of the calcium sulfate–chloride type. Overall, 87% of water samples were inappropriate for drinking purposes, while 77.8% were unsuitable for irrigation.