| 雷州半岛岭北地区地下水水文地球化学特征 |
| 摘要点击 2353 全文点击 789 投稿时间：2020-02-26 修订日期：2020-05-19 |
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| 中文关键词 水化学 氢氧同位素 水文地球化学过程 地下水 雷州半岛 |
| 英文关键词 hydrochemistry H and O isotopes hydrogeochemical processes groundwater Leizhou Peninsula |
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| 中文摘要 |
| 地下水是雷州半岛重要的供水水源.本研究在雷州半岛岭北地区开展了水化学和氢氧稳定同位素调查，报道了区域地下水水化学特征；基于水化学及同位素地球化学理论和方法揭示了控制水质的主要水文地球化学过程.结果表明，地下水pH、总硬度、TDS以及K+、Cl-、SO4-质量浓度较低；H2SiO3和NO3-质量浓度较高.孔洞裂隙水水化学类型以Mg-Ca-HCO3和Mg-Ca-HCO3-Cl型为主，Cl-沿径流方向增加明显；浅层孔隙水以Ca-Cl、Na-Ca-HCO3-Cl和Na-Ca-Mg-HCO3-Cl型为主；中深层孔隙水以Mg-Ca-HCO3、Na-Ca-Mg-HCO3和K-Na-HCO3-SO4型为主，K+、Na+、Cl-和SO4-沿径流方向有所增加.地下水受大气降水补给，Cl-和Na+起源于海洋性大气降水，Mg+、Ca2+和HCO3-源自硅酸盐矿物水解，NO3-主要来自化学肥料；浅层孔隙水、裂隙孔洞水受蒸发浓缩作用影响，中深层孔隙水受阳离子交换作用影响.计入硝酸盐后，50.85%的NO3型水指示着地下水具有污染趋势.本研究结果为可持续开发利用区域地下水提供了依据. |
| 英文摘要 |
| Groundwater is an important source of water supply in the Leizhou Peninsula. In August 2018, five surface water samples, 18 shallow pore water samples, 14 middle-deep pore water samples, and 27 pore fissure water samples were collected in the Lingbei area, the northern part of the Leizhou Peninsula. Major ion concentrations, as well as H, O isotope composition (of δ18O and δ2H) were analyzed. The results show that groundwater pH values, total hardness, concentrations of K+, TDS, Cl-, and SO42- are low, while H2SiO3(aq) and NO3- concentrations are relatively high. For pores and fissures water, hydrochemical types are mainly Mg-Ca-HCO3, Mg-Ca-HCO3-Cl, and Cl- loadings are significantly increased along the flow path. Ca-Cl, Na-Ca-HCO3-Cl, and Na-Ca-Mg-HCO3-Cl types predominate in shallow pore water. For middle-deep pore water, the types are primarily Mg-Ca-HCO3, Na-Ca-Mg-HCO3, K-Na-HCO3-SO4, and concentrations of K+, Na+, Cl-, and SO42- are modestly increased along the flow path. We find that the groundwater is of meteoric origin, groundwater Cl- and Na+ originate from marine atmospheric precipitation, Mg+, Ca2+, and HCO3- are mainly derived from silicate weathering, and NO3- principally arises from chemical fertilizer. Shallow pore water and fissure pore water are affected by evaporation concentration, whereas cation exchange is important for middle-deep pore water. The milligram equivalent ratio of nitrate in groundwater reaches 28.3%. After taking into account the nitrate, 50.85% of the sampling water is NO3 type, and displays a pollution trend. Our results contribute to the sustainable utilization of groundwater in the study area and other similar areas. |
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