Quality assessment of qanat water for drinking and agricultural uses in Tehran

Abstract

Underground water is one of the water resources applied to multiple uses in Tehran City. Hence, today, water resources management and investigation is of high importance and necessity. In the present study, 19 Qanat selected of 65 Qanat of Tehran were identified and sampling was conducted to assess the water quality and quantity. Principal variables such as EC, TDS, pH, TH, DO and others like as Cl, K, Na, etc., were measured and analyzed. The concentration of anions and cations was measured by titration method. Due to low amount of DO and high amount of some cations and anions available in the studied water, sampled Qanat water was reported unacceptable for drinking use based on the determined standards of Environmental Protection Agency. Although pH value of the sampling Qanat water was within the standard limit for different uses, but pH parameter is not to be considered as a determinant factor, because drinking water needs to have several other parameters within permissible limits. According to available standards, all Qanat water is useable for agricultural purposes. Also, quality situation of Tehran Qanat water was reported in Good, Acceptable and medium limits based on Schoeller Diagram.