Preliminary assessment for physicochemical quality parameters of groundwater in Oqdus Area, Saudi Arabia

The shortage of renewable water resources in Saudi Arabian makes groundwater a major water stock basis in many provinces. Therefore, regular monitoring is essential. This study was conducted to assess groundwater quality in the Odqus area, Saudi Arabia, for domestic and irrigation uses. Water samples were collected from 51 wells in July and August of 2013, and analyzed for pH, levels of total dissolved solids (TDS), total hardness (TH), and the content of major anions and cations. The results indicated that the pH, NO3, NO2, Br and F in all samples were below the local drinking water guideline: SASO (Saudi Standards, Metrology and Quality Organization) values, although a small fraction of samples (7.14%) were above the recommended TDS content. Correspondingly, only a slight percentage of the samples failed the tests for K, Na, Cl, and SO4 ions (1.96%, 5.88%, 7.84% and 5.88%, respectively). Despite the majority (98%) of the samples were below the SASO recommended maximum standard for TH in groundwater (500mgL−1), however, most of the samples were classified as moderately hard (58.82%) or hard (33.33%), with a minute fraction of samples classified as very hard (7.84%). This classification is likely related to the accessibility of Ca and Mg because a significant percentage of the samples failed the guidelines for Ca and Mg concentration (64.70% and 35.29%, respectively). The Perceptible variation in almost all investigated parameters might be related to local geological formations and agricultural activities due to the absence of other anthropogenic pollution sources. Sodium adsorption ratio (SAR) and Wilcox classifications, indicate that the majority of samples are adequate for irrigation proposes.