Chemical and Isotope Studies of Zakher Lake and Its Possible Risk on the Geoenvironment, Al Ain, United Arab Emirates

Abstract

This study concerns the occurrence of pollutants in Zakher Lake, Al Ain, UAE, which are relevant to the water supply and impact on ecosystem. Lake water and sediment samples were collected from the lake and were analyzed for different chemical and physical properties. In-situ measurements of temperature, pH, EC and TDS and Rn-222 activity were carried out using a WTW-COND-330I and RAD7 instrument with errors of < 5%. The analyses of trace and major elements were performed using inductively coupled plasma optical emission spectroscopy (ICP-OES) Varian 715 with errors < 5%. The results reveal high concentrations of Na, K, Mg and Ca, Fe, Mn, Al, Sr, Ba and Pb in water samples of the lake, which are higher than permissible limits for drinking and irrigation. Variable concentrations of these elements were found in the sediment samples. In addition, radon isotope (Rn-222) data in the lake water indicate activity values below the detection limit of the instrument. The high concentrations of major and trace elements support the idea that the water is polluted. The sources of water to the lake are considered mainly anthropogenic due to the relatively high activity of Rn-222 in surrounding groundwater wells that is not detected in the lake water. Consequently, the lake water is not suitable for drinking, domestic or irrigation purposes and may be considered as a source of environmental hazard in the area.