Chemistry of Groundwater of Al-Ahsa Oasis Eastern Region Saudi Arabia and Its Predictive Effects on Soil Properties

Abstract

Saudi Arabia is an arid and the largest country in the middle east with a total land area of 2.253 x 10(6) km2. Recent urban and rural expansion has shown manifold increases in water use in various sectors. Water resources are limited and non-renewable coupled with unpredicted scanty rainfall. In order to meet the rising water needs, evaluation of water quality is important for allocation to various uses. A total of 101 well water samples were collected from Al-Ahsa Oasis. Water samples were analyzed for total salt concentration, pH, Ca, Mg, Na, K, HCO3, Cl, SO4, NO3, F and B contents. Soil Salinity Development (SSD), adjusted sodium adsorption ratio (adj.SAR), adjusted sodium adsorption ratio (adj. R(Na)) and Exchangeable Sodium Percentage (ESP) were calculated. The EC of groundwater ranged between 1.23 and 5.05 dS m(-1). Sodium was the most abundant cation followed by Ca, Mg and K in descending order. Chloride was the most abundant anion followed by SO4 and HCO3 in groundwater of Al-Ahsa Oasis. A significant correlation was found between Na and Cl (R2 = 0.936). Thermodynamics calculation revealed that an appreciable amount of Ca and Mg is associated with Cl and SO4 ions. The SAR and ESP values are within the permissible limits according to Ayers and Westcot, 1985. The NO3 concentration is within safe limits for drinking purpose according to WHO (1998) standards. The Saturation Indices (SI) indicated that groundwater is under-saturated (negative SI) with respect to certain minerals (for example: calcite, dolomite, gypsum, anhydrite, halite, pyrite, fluorite and aragonite) and oversaturated (positive SI) with respect to some other minerals (For example: Goethite, Siderite and hematite). The negative saturation index (SI) reveals that most of minerals are in un-saturated state and will dissolve more Ca and Mg into the soil solution after irrigation. A good relationship exists between Cl and other ions (Na, Ca and Mg) as well as between SO4 and Ca and Mg ion of groundwater. The salinity and sodicity hazards of groundwater of Al-Ahsa Oasis were classified as C3S1 and C4S2 i.e., high salinity with medium sodicity problems. The predicted soil salinity suggested application of 15-20% leaching requirements to keep soil salinity within permissible limits. Cultivation of slight to moderate salt and sodium tolerant crops is recommended for optimal agricultural production and efficient water use.

Chemical Composition and Amounts of Mineral Elements in Honeybee-Collected Pollen in Relation to Botanical Origin

“…For example: the electrical conductivity of groundwater used for irrigation in Al-Ahsa oasis ranged between 1.23 and 5.05 dS m-1 with Na as the most abundant cation. The groundwater of Al-Ahsa Oasis is mainly Na and Ca water rather than Ca and Mg dominant water (Al-Zarah, 2008). The mineral elements in the selected bee pollen showed a predominance of Na (35.54,35.32,26.91,31.50,and 28.44 % of the total mineral quantified), K (34.92,34.73,26.53,31.16,and 28.06 %),Ca (11.69,14.62,23.33,19.80,and 22.27 %) and Mg (15.11,12.75,19.39,14.67,and 17.73 %) for sunflower, summer squash, date palm, rape, and alfalfa, respectively.…”

Studies of Al Asfar and Al Uyoun Evaporation Lakes Water Quality and the Potential of Its Reuse in Agriculture Activities, Al Hassa Area, KSA

“…Al Uyoun Lake Hydrogeology and hydrochemistry of groundwater of Al Hassa area have been reported in many studies (Etewy, et al, 1983;Al-Mahmoud, 1987;Abderrahman, 1988;Edgell, 1989;Al Dakheel and Al Safarjalani, 2005;Al Safarjalani and Almadini 2007;Al-Zarah, 2007 and2008;and Al Dakheel, 2009). …”

Monthly Variations of Physico-Chemical Properties from a Man-Made River in Saudi Arabia

“…Several criteria for water quality requirements had been recognized which serve as guidelines for use in determining the suitability of water for various uses. In Saudi Arabia, the quality of water is currently receiving considerable attention from environmental and water scientists (Al-Redhaiman and Magid, 2002;Al-Turki and Magid, 2003;Al-Matroud, 2003;Al-Zarah, 2008;Al-Turki, 2009;Al-Hawas, 2002). Therefore, assessment of water quality is a major N requirement in the planning stages of any new development.…”