Application of hydrochemistry and stable isotopes (δ34S, δ18O and δ37Cl) to trace natural and anthropogenic influences on the quality of groundwater in the piedmont region, Shijiazhuang, China. (August 2016)

• Record Type: Journal Article
• Authors: Zhou, Jianwei; Zhang, Yanpeng; Zhou, Aiguo; Liu, Cunfu; Cai, Hesheng; Liu, Yunde
• Is Part Of: Applied geochemistry. Volume 71(2016:Aug.)
• Page Start: 63
• Page End: 72
• Publication Date: 2016-08
• Subjects: Groundwater pollution -- δ34SSO4 and δ18OSO4 -- δ37Cl -- Multiple solute sources -- Bacterial sulfate reduction; Environmental geochemistry -- Periodicals; Water chemistry -- Periodicals; Geochemistry -- Social aspects -- Periodicals; Geochemistry -- Periodicals; 551.9
• DOI: 10.1016/j.apgeochem.2016.05.018
• Languages: English
• ISSNs: 0883-2927

Abstract

Abstract: Because of their frequent association with man-made products, increasing SO 4 2 − and Cl − concentrations are often important indicators of deterioration of groundwater quality. The integrated use of hydrochemistry and multi-isotopic approaches (δ 34 S, δ 18 O and δ 37 Cl) was applied in Shijiazhuang area, China, to characterize SO 4 2 − and Cl − sources; and to evaluate factors, including natural processes and anthropogenic activities, that affect groundwater quality. In the plain area, the SO 4 2 − concentrations of the surface water and shallow groundwater (mean 2.42 mmol/L and 2.06 mmol/L, respectively) were generally higher than those of the deep groundwater (mean 0.69 mmol/L). The natural waters in the mountain area (mean 4.36 mmol/L) had higher SO 4 2 − contents than those in the plain area (mean 1.73 mmol/L). The shallow groundwater samples collected in the southern part of the plain area had higher Cl − concentrations than other samples. The SO 4 2 − in natural waters showed variable δ 34 S and δ 18 O values, ranging from +8.7‰ to +21.7‰ and from +5.9‰ to +11.4‰, respectively. The δ 37 Cl values fell in a narrow range of −0.22‰ to +0.64‰ with a mean value of +0.14‰. The hydrochemistry of samples is in part controlled by water-rock interaction processes, but also influenced by anthropogenic activities. The variations of δ 34 S and δ 18 O values indicate gypsum, oxidation of inorganic sulfide minerals, and detergents are the primary sources of sulfate in the samples. Bacterial SO 4 2 − reduction is an important reaction affecting the SO 4 2 − concentrations in the deep groundwater of the plain area. The plot of δ 37 Cl and 1/Cl − combined with the δ 37 Cl information of potential Cl − sources suggests that the dissolved Cl − in natural waters is mainly sourced from dissolution of Cl-bearing minerals, import of wastewater, and precipitation. Given the above, the elevated concentration of SO 4 2 − and Cl − in the groundwater could be mainly attributed to mining activities in the mountain area and input of wastewater from domestic and industrial activities. Highlights: Isotopic compositions of groundwater sulfate and chloride were determined. Mixing between a variety of natural and anthropogenic sources controlled groundwater quality. Dominant pollution sources were mining (in mountain areas) and wastewater (in plain areas). Bacterial sulfate reduction has affected the deep groundwaters.