نوع مقاله : مقاله پژوهشی
نویسندگان
1 دانشگاه شهید بهشتی
2 استاد آبهای زیرزمینی دانشگاه شهید بهشتی
3 شهید بهشتی
چکیده
کلیدواژهها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
Karstic springs, which are one of the main sources of drinking water supply in Khuzestan, are highly vulnerable to contamination. The aim of this research is to investigate the hydrochemistry of major ions and determine the origin of sulfates in sulfuric springs, non-sulfuric springs (springs contaminated with oil), and oil brines in southwestern Iran using stable sulfur isotopes. For this purpose, six samples of sulfuric groundwater, seven samples of non-sulfuric groundwater, and six samples of oil brines were collected and analyzed for major ions and stable isotopes δ34SSO4 and δ18OSO4. Hydrochemical composition diagrams were used to infer the rock/water interaction and identify hydrogeochemical processes. Isotopic diagrams of δ34SSO4 and δ18OSO4, as well as combined diagrams of sulfates and major ions, were used to identify the origin of sulfates. Groundwater samples exhibit three specific anionic facies: sulfate-calcic resulting from gypsum dissolution, bicarbonate-calcic from calcite dissolution, and chloride-sodic from contamination by oil brines. Based on hydrogeochemical and isotopic composition diagrams, three interacting processes of water and rock (gypsum dissolution, carbonate dissolution, and halite dissolution) in the karstic aquifers under study were identified. Among these processes, gypsum dissolution appears to be the primary contributor to the composition of solute in karstic aquifers. The isotopic values of δ34SSO4 in groundwater range from 18.06 to 33.06, and the values of δ18OSO4 range from 11.07 to 16.07, indicating that sulfate is derived from the interaction of water and evaporitic rocks (gypsum dissolution in the Gachsaran Formation or gypsum present in carbonate reservoirs).
کلیدواژهها [English]
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