نوع مقاله : مقاله پژوهشی

نویسندگان

• Parisa Piroozfar ¹
• Samad Alipour ²
• Soroush Modabberi ³
• David Cohen ⁴

¹ Ph.D. Student, Department of Geology, Faculty of Sciences, Urmia University, Urmia, Iran

² Professor, Department of Geology, Faculty of Sciences, Urmia University, Urmia, Iran

³ Associate Professor, School of Geology, University of Tehran, Tehran, Iran

⁴ Associate Professor, School of Biological, Earth and Environmental Sciences, New South Wels University, Sydney, Australia

چکیده

This study investigated the hydrogeochemistry and environmental water quality of rivers in Sarough watershed using the major ion chemistry and explored multivariate statistical methods for identification of processes which release the solutes in natural waters. Totally, 38 samples were collected along the main streams of the watershed. The mean concentrations of major cations (Na, K, Mg, Ca) and anions (Cl, NO₃, CO₃, HCO₃, SO₄) were measured about 15, 4.6, 10.5, 61, 30, 4.49, 89, 156 and 107 mg/l, respectively. The results indicated that the river waters in the Sarough watershed were neutral and fresh water in nature (mean values: pH=7.7 and TDS= 315.8 mg/l). Most of the water samples were categorized in hard and very hard water classes with mean value for TH=197 mg/l and were under-saturated regarding with major carbonates, sulfates and evaporate minerals in most of samples. The major water types were Ca–HCO₃–SO₄, Ca–Mg–CO₃ and Ca–SO₄–HCO₃. The Na, Cl and NO₃ concentration in all water samples fell within the accepted limit of national and international standards for drinking water. Nevertheless, Ca, Mg and SO₄ content in some samples were higher than the maximum desirable limits. Schuler diagram showed that majority of the water samples were good and acceptable for drinking. Evaluating the quality of river water for irrigation purposes using Wilcox diagram and SAR, EC and RSC indices indicated that majority of the water samples were suitable for irrigation. The results of multivariate statistical techniques such as correlation coefficient matrix, CA and PCA indicated the strong association between Na-K-Cl-SO₄ and Ca-Mg-CO₃-TH. It was assumed that weathering of carbonates (limestone/dolomite formations, calcareous marl formation and travertine) in the area were common source of Ca, Mg and HCO₃. Also, travertine springs were considered as active point sources which release these elements into the drainage system. Meanwhile, dissolution of halite and gypsum in red marl formations (lower part of Qom F. and Upper Red F.) were the main processes considered as the origin of Na, K, Cl and SO₄ in river water of study area.

کلیدواژه‌ها

• Water quality assessment
• Sarough watershed
• Hydrogeochemistry
• PCA
• Piper Diagram

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