Investigation of geochemical interactions of groundwater resources of Kamarderaz anticline plunge using statistical methods, Southwest of Izeh city

Karstic aquifers are one of the most important freshwater resources, and in some areas, they are the only available water resources. These resources have significant challenges, including reduced quality and increased pollution. Izeh city in the southwest of Iran intensively depends on karstic water resources due to lack of access to surface water streams. Accordingly, five water wells were drilled to supply part of the city's and surrounding villages' drinking water in the Kamarderaz anticline plunge. During the drilling in the Atabaki area, two wells encountered H2S gas penetration and increased Ec during drilling, making the wells cumbering. The chemical parameters of water resources were measured to investigate the causes of qualitative changes in 4 states during two seasons in spring and summer over 2017-2018. Na /Cl, Br /Cl, I /Cl ion ratios, and Total Organic Carbon Index (TOC) was used to differentiate salinity sources, water sources mixing with brine, and the infiltration of hydrocarbons into water. In this study, statistical analysis, including PCA and AHC, was used to more accurately investigate the factors affecting the qualitative changes in the region. According to the statistical analysis in the area, two factors of carbonate mineral dissolution, evaporation and brine infiltration, have simultaneously affected the water quality, especially in the western part of the plunge anticline. TOC analysis and Na /Cl, Br /Cl, and I /Cl ratios illustrated the mixing of water and oil brines and infiltration of hydrocarbons.