Abstract
Twenty-four groundwater samples were collected at different
depths within the Dammam aquifer and Quaternary deposits. A
detailed hydro-chemical study of water samples was conducted,
including physical properties; Hydrogen number (pH), total
dissolved solids (TDS), and electrical conductivity (EC), while
the chemical analysis included the major anions; SO4-2, Cl-,
HCO3-, and major cations; Ca+2, Mg+2, Na+, and K+, in addition
to the minor element (NO3-). The results indicate a neutral to
slightly alkaline water with pH of 7.17 which characterized by
hard water that is neutral- slightly alkaline water. The TDS exceeds
the permissible limits for drinking, with an average of 2787
ppm, which represents slightly brackish water. Conductivity EC
indicates heavily mineralized water with EC of 4310.8 μs/cm. The
predominant cation was Mg+2, and Na+, while the predominant
anions were SO4-2, and Cl-. The prevalent cation in the aquifer
Na+ of 49%, followed by Ca+2 of 30%, Mg+2 of 17%, and K+
of 4%, while the prevalent anion was SO4-2 of 48%, Cl- of 31%,
and HCO3- of 21%. Groundwater is classified as unsuitable for
drinking, while it is suitable for irrigation. The water type is Na-
SO4 affected by the interaction between aquifer material (Halite,
dolomite, and calcite), and the groundwater in contact.