Appraisal of changes in groundwater quality of Tasouj aquifer and approaches to improve the quality of water from this aquifer

Review of long-term changes in groundwater quality help to understand the quality of aquifer and manage it to improve and stay in good shape. Since the water needed for drinking and farming of Tasouj plain is provided from groundwater resources, it is important to study the process of changes in the quality of these resources. Quality changes of this resources are affected by many factors; one of these factors is the proximity of this aquifer to Lake Urmia and extra withdrawal of these resources in Tasouj aquifer. In this study, changes in Total Solids Solubility (TSS) and its effect on Electrical Conductivity (EC) of groudwater along with existing Chloride, changes in taken samples in the aquifer area during the 10-year period has been studied. The results clearly show the increasing trend of EC in relation to the increase in total soluble materials and the deterioration in groundwater quality. Also, the high correlation coefficient obtained from the comparison of Cl and TDS with EC, which are R2 = 0.94 and R2 = 0.87, respectively, expresses direct impact of water quality of this aquifer to Cl. It is noteworthy that the trend of Cl changes in the aquifer has been rising over the past ten years and gained from 4.69 to 8.36 in the term of the study period. Considering that corrosion of chlorine and strong desire for interaction with metals such as iron, manganese and zinc, Sodium thiosulfate Sodium thiosulfate can reduce the high proportion of water-soluble metals by eliminating chlorine.