Evaluation of groundwater resources for drinking and agricultural purposes, Abar Al Mashi area, south Al Madinah Al Munawarah City, Saudi Arabia

A hydrogeochemical study was conducted on the groundwater of south Al Madinah Al Munawarah City, Saudi Arabia, to assess the quality of groundwater for drinking and irrigation uses. Groundwater samples have been collected and analyzed for major and some trace constituents from the study area. The nitrate concentration in most groundwater samples of the study area exceeded the safe limits for drinking purposes, whereas the concentrations of phosphate, boron, and trace constituents were below the maximum permissible limit for drinking purposes; Cr in two samples showed high content over the recommended limits of drinking purposes. Uncontrolled abstraction of groundwater in Abar Al Mashi area caused many environmental problems including water resource depletion and contamination. Correlations between chloride and major ions were positive and may be attributed to impact of agricultural activities on groundwater chemistry. Groundwater of the study area was classified into six water types. The chemical water types of groundwater in the study area contain CaHCO₃ in the eastern and southeastern parts and NaCl in western and northwestern parts, reflecting different land use characteristics and pollution sources. Piper diagram showed that almost all the samples fall in one zone, indicating similar chemical signature. Groundwater can be used safely for drinking with special treatments to eliminate the effect of increased concentrations of total dissolved solids, nitrate, and chromium. The groundwater of the study area can be used safely for irrigation on clay soil; however, specific crops should be selected according to their salt tolerance.