Document Type : Original Article
Department of Environmental Sciences and Engineering, Roudehen Branch, Islamic Azad University, Roudehen, Iran.
Department of Environmental Sciences, Department of Environmental Sciences and Engineering, Roudehen Branch, Islamic Azad University, Roudehen, Iran.
Qanat is a valuable source of groundwater, the maintenance of which requires quantitative and qualitative monitoring. Since the Qanat water is currently used in some parts of Iran for drinking and agricultural purposes, its quality management is of great importance. The purpose of this study was to evaluate the water quality of Qanat in the eastern areas of Tehran.
Water sampling was performed from eight Qanats in the east Tehran in triplicate (mother well, one of the access shafts and outlet) based on standard methods during the summer of 2020. The measured parameters included pH, total dissolved solids, electrical conductivity, CO32-, HCO3-, Na2+, Ca2+, Mg2+, K+, Cl-, NO3, SO42-, total hardness and total alkalinity, whose quality was assessed according to the World Health Organization and the Food and Agriculture Organization. Groundwater Quality Index (GWQI) was used to classify the water quality of Qanats.
The lowest (56.05) and the highest (2058.58) GWQI scores corresponded to Qanats 5 (Elimon) and 8 (Aminabad) with good and very poor quality, respectively. There was a decrease in the water quality in Qanats 8 (Aminabad), 7 (Sulaymaniyah), 6 (Mehdiabad) and 2 (Majidieh) in East Tehran, respectively.
The studied Qanats were in the range of good to very poor. The reasons for difference in water quality were due to the direction of anthropological pollutants and geological structures. To control the water quality of Qanats in the east of Tehran, the quality monitoring network is recommended to be designed for various pollutants and optimized for the long term.