Distribution characteristics and source analysis of sulfate in the main rivers of Heze city, China

Throughout the last few decades, sulfate concentrations in streamwater have received considerable attention due to their dominant role in anthropogenic acidification of surface waters. In order to determine the cycle of riverine sulfate, affected by natural weathering and anthropogenic activities, the Zhuzhaoxin River Basin and Dongyu River Basin in Heze City, China are selected. The conventional hydrochemical characteristics, distribution characteristics of sulfate concentration, and distribution characteristics of sulfur and oxygen isotopes are analyzed and texted. The results are as follows: the concentration of SO₄^2- in the surface water of the study area increased gradually from upstream to downstream. In the study area, the δ³⁴S_SO4 and δ¹⁸O_SO4 value in the surface water of Zhuzhaoxin River Basin ranges from +8.0‰ to +22.3‰ and +7.3‰ to +10.5‰, respectively, while the values of Dongyu River Basin are between +9.3‰ ∼ +9.5‰ and +4.2‰ ∼ +8.1‰. The main sources of SO₄^2- in the Zhuzhaoxin River Basin are domestic sewage, industrial and mining wastewater and the evaporation of dissolved salt rock, and their average contribution rates are more than 50% and 30%, respectively; the main sources of SO₄^2- in the Dongyu River Basin are agricultural activities and atmospheric precipitation, and their average contribution rates are more than 60% and 20%, respectively.