Hydrogeochemistry mechanism contrasts between low and high sulfate in limestone aquifers at the massive coalfield in Anhui province, China

Autor: Jiying Xu, Herong Gui, Caifang Wu, Yan Guo, Jun Li, Chen Li, Jiayu Chen
Jazyk: angličtina
Rok vydání: 2022
Předmět:
Zdroj: Water Supply, Vol 22, Iss 8, Pp 6978-6993 (2022)
Druh dokumentu: article
ISSN: 1606-9749
1607-0798
DOI: 10.2166/ws.2022.265
Popis: High sulfate mine groundwater at the Huaibei coalfield has exceeded the permissible limit (250 mg/l) of World Health Organization, posing serious threat to nearby water resource. A total of 28 samples were collected from Taiyuan formation aquifer (TA) and Ordovician aquifer (QA). In view of the mean concentration in two aquifers, the TA and OA were identified as high sulfate group and low sulfate group. The contrast on hydrochemical characterization and water-rock interactions were analyzed to reveal the mechanism of sulfate enrichment in mine groundwater. Compared with low sulfate groundwater, the high sulfate groundwater possess a higher content of TDS, Na+ and Cl−, which elevated by 3.83, 4.0 and 3.29 times, respectively. The low sulfate groundwater is controlled by Ca-Na-HCO3 type (82%), whereas the high sulfate groundwater is dominated by Na-SO4-HCO3 type (88%). The geochemical process of low sulfate groundwater is influenced by dissolution of carbonate minerals and weak ion exchange. The mechanism of sulfate enrichment in mine groundwater are predominately controlled by both silicate and carbonate minerals weathering, strong ion exchange interaction and competitive effect. The outcomes enhance understanding of the mechanism of high sulfate mine water and provide theoretical support for mine wastewater treatment. HIGHLIGHTS Hydrogeochemistry mechanism contrasts between low and high sulfate in limestone aquifers were studied.; Water environment for high sulfate mine groundwater was revealed from comparative analysis with low sulfate mine groundwater.; Corresponding minerals dissolution dominated the hydro-chemistry process together with ion exchange and competitive effect.;
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