Zhang Hong-Xin, Wu Ya, Luo Wei-Yu, Chen Wen, Liu Huai-Qing
Wuhan Center of China Geological Survey, Wuhan 430205, China.
NO.4 Geological Party, Guangdong Geological Bureau, Zhanjiang 524049, China.
Huan Jing Ke Xue. 2020 Nov 8;41(11):4924-4935. doi: 10.13227/j.hjkx.202002187.
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 O and H) were analyzed. The results show that groundwater pH values, total hardness, concentrations of K, TDS, Cl, and SO are low, while HSiO and NO concentrations are relatively high. For pores and fissures water, hydrochemical types are mainly Mg-Ca-HCO, Mg-Ca-HCO-Cl, and Cl loadings are significantly increased along the flow path. Ca-Cl, Na-Ca-HCO-Cl, and Na-Ca-Mg-HCO-Cl types predominate in shallow pore water. For middle-deep pore water, the types are primarily Mg-Ca-HCO, Na-Ca-Mg-HCO, K-Na-HCO-SO, and concentrations of K, Na, Cl, and SO 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, Ca, and HCO are mainly derived from silicate weathering, and NO 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 NO type, and displays a pollution trend. Our results contribute to the sustainable utilization of groundwater in the study area and other similar areas.
地下水是雷州半岛重要的供水水源。2018年8月，在雷州半岛北部的岭北地区采集了5个地表水样品、18个浅层孔隙水样品、14个中深层孔隙水样品和27个孔隙裂隙水样品。分析了主要离子浓度以及氢、氧同位素组成（氧和氢）。结果表明，地下水的pH值、总硬度、钾、总溶解固体、氯和硫酸根浓度较低，而偏硅酸根和硝酸根浓度相对较高。对于孔隙和裂隙水，水化学类型主要为Mg-Ca-HCO₃、Mg-Ca-HCO₃-Cl，且沿水流路径氯含量显著增加。浅层孔隙水以Ca-Cl、Na-Ca-HCO₃-Cl和Na-Ca-Mg-HCO₃-Cl类型为主。中深层孔隙水的类型主要为Mg-Ca-HCO₃、Na-Ca-Mg-HCO₃、K-Na-HCO₃-SO₄，且钾、钠、氯和硫酸根浓度沿水流路径适度增加。我们发现，该地下水来源于大气降水，地下水中的氯和钠源自海洋大气降水，镁、钙和碳酸氢根主要来源于硅酸盐风化，硝酸根主要来源于化肥。浅层孔隙水和裂隙孔隙水受蒸发浓缩影响，而阳离子交换对中深层孔隙水很重要。地下水中硝酸盐的毫克当量比达到28.3%。考虑硝酸盐后，50.85%的采样水为NO₃型，呈现污染趋势。我们的研究结果有助于研究区及其他类似地区地下水可持续利用。
