Investigating the changes in chemical quality characteristics of Ardestan plain underground water resources during 1995-2019.

Objectives: Considering the importance of underground water sources, continuous evaluation of their quality should be considered to prevent chemical pollution. Therefore, the purpose of this research is to investigate the changes in the chemical quality of water in the Qanats (aqueducts) and wells of Ardestan Plain during the years 1995 to 2019. Methods: This research was conducted retrospectively in 2021 based on the data collected by Ardestan Department of Natural Resources during the period of 1995-2019. Data were analyzed by SPSS software, version 2016 and compared to Iranian drinking water quality standards. Results: Data showed that Total Dissolved Solids (TDS) and the Total Hardness of well water were increased 367.3, 168.8 respectively. These parameters were increased by 188.1 and 90 mg L^-1 for Qanat water, respectively. And other water quality parameters were increased including magnesium, calcium, sulfate, bicarbonate, chloride and Electrical Conductivity (EC). The trend of TDS and TH showed that in the all of the well water exceeded from the drinking water standard especially in 2019. Conclusion: Paying attention to the process of chemical changes of water in the Ardestan plain reminds us that in the future, water sources will be at risk of damage, especially in the low-altitude parts of the plain. [ABSTRACT FROM AUTHOR]