EVALUATION OF GROUNDWATER QUALITY IN THE EASTERN DISTRICT OF ABU DHABI EMIRATE, UAE

摘要

In this paper, chemical data (major ions) have been used to improve the understanding of the ground water salinity, and in particular, to evaluate the ground water quality in the shallow unconfined alluvial aquifer beneath the city of Al Ain (northeastern part of Abu Dhabi Emirate). Ground water samples were collected for chemical data from 28 wells in 2012. The chemical monitoring revealed high spatial variability in chemical parameters as influenced by climate, matrix aquifer changes in geological formations, water table depth, and the under Jabal Hafit limestone aquifer. Results show that changes in ground water chemistry in the aquifer is 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 sulphate. The high total dissolved solids (TDS) of shallow ground water beneath the city of Al Ain (up to 5640 mg/L) is mainly controlled by evaporation. In general, the ground water quality was good. Many of the chemical constituents analysed in each sample are within the primary drinking water standards. Ground water south of the study area (northern edge of Jabal Hafit) shows a poorer quality than the northeast and the east areas (near Oman Mountains).