Coupling hydrochemistry and stable isotopes (δ2H and δ18O) to identify the major factors affecting the hydrochemical evolution of groundwater in the Western Yellow Sea Coast, China. (March 2022)

• Record Type: Journal Article
• Authors: Wang, Zhenyan; Su, Qiao; Wang, Shu; Gao, Zongjun; Liu, Jiutan
• Is Part Of: Applied geochemistry. Volume 138(2022)
• Publication Date: 2022-03
• Subjects: Groundwater -- Hydrochemistry -- Stable isotopes -- Coastal zone -- Seawater intrusion; Environmental geochemistry -- Periodicals; Water chemistry -- Periodicals; Geochemistry -- Social aspects -- Periodicals; Geochemistry -- Periodicals; 551.9
• DOI: 10.1016/j.apgeochem.2022.105221
• Languages: English
• ISSNs: 0883-2927

Abstract

Abstract: Groundwater, as an invaluable freshwater resource, has a significant impact on the social and economic development of coastal areas. The Western Yellow Sea coast (WYSC), located in the eastern part of China, is considered one of the most prosperous areas in terms of economic development, with considerable demand for water. In this study, a total of 160 groundwater samples were collected in the field, for which the Ca 2+, Mg 2+, Na +, K +, Cl −, SO4 2−, HCO3 −, F −, Br −, δ 2 H, and δ 18 O contents were determined. We studied the chemical characteristics, sources of dissolved substances, hydrogeochemical processes, and the difference between the chemical characteristics of groundwater in two areas of the WYSC, the Shandong part (SDP) and Jiangsu part (JSP). The results indicate that the major sources of dissolved substances in the groundwater of WYSC were mineral dissolution and seawater intrusion (SWI). SDP was mainly affected by mineral dissolution, whereas JSP was significantly affected by SWI. The major source of groundwater recharge in the WYSC was precipitation; moreover, the groundwater recharge was affected by seawater and evaporation. The groundwater in the SDP was affected by modern SWI, whereas that in JSP was affected by palaeo SWI. SWI not only directly changes the chemical composition of groundwater via mixing but also indirectly changes it by influencing the hydrogeochemical processes. SWI can also lead to the formation of high-fluoride groundwater. Therefore, feasible measures should be incorporated to prevent SWI and ensure drinking water safety for the inhabitants. Highlights: Mineral dissolution and seawater intrusion dominance the groundwater chemical composition of Western Yellow Sea coast. Groundwater evolution in coastal aquifers of Shandong part is slightly affected by modern seawater intrusion. Groundwater evolution in coastal aquifers of Jiangsu part is strongly affected by palaeo seawater intrusion. Seawater intrusion resulted in high-fluoride groundwater in coastal aquifers.