Hydrochemistry assessment of groundwater quality in Al-Ain city, UAE

Groundwater is the main source for irrigation purposes in Al-Ain city. Urbanization and agricultural activities are considered potential sources of groundwater pollution in this area. Therefore, assessment of groundwater quality is very important to detect and prevent contamination for effective groundwater management. This paper focuses on the impact of urbanization on the groundwater resources of the gravel alluvial aquifer in the vicinity of Al-Ain city (northeast of Abu Dhabi Emirate). Groundwater samples were collected from 28 wells in Al-Ain city. The chemical monitoring revealed high spatial variability in chemical parameters as influenced by climate, matrix aquifer changes in geological formations, and water table depth. Results show that changes in groundwater chemistry in the aquifer are mainly controlled by evaporation, silicate mineral dissolution, evaporite dissolution, cation exchange, and mixing by upward leakage from Jabal Hafit limestone aquifer. The concentration increases were accounted for primarily by dissolved sodium, chloride, and sulfate. The high total dissolved solids (TDS) of shallow groundwater beneath the city of Al-Ain (up to 5640 mg/L) are mainly controlled by evaporation. Groundwater quality was better in the northeast and the east areas (near Oman Mountains) compared to the south area (northern edge of Jabal Hafit).