| 盐城地区地下水溶质来源及其成因分析 |
| 摘要点击 1809 全文点击 768 投稿时间：2021-07-09 修订日期：2021-09-16 |
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| 中文关键词 地下水 水化学组成 控制因素 人类活动 盐城地区 |
| 英文关键词 groundwater hydrochemical composition controlling factors human activities Yancheng area |
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| 中文摘要 |
| 位于淮河下游典型冲海积平原区的盐城，地下水具有开发利用程度高，浅层水显著咸化的特点.在浅层地下水空间采样的基础上，通过各要素空间分布、Pipper、水化学侵蚀模式和富集因子法，研究离子的主要来源及其成因，探讨人类活动的作用.结果表明：①浅层地下水中溶解性总固体（TDS）范围为211~3790 mg·L-1，其中，微咸水样品占30.28%.阴、阳离子浓度顺序分别为：HCO3->Cl->SO4>2-NO3-和Na+>Ca2+>Mg2+>K+，但从Ⅰ、Ⅱ类水至Ⅴ类水中，随TDS值增大，居支配地位的阴、阳离子分别由HCO3型向Cl/SO4型和Ca型向Na型演化.②初始的Ⅰ、Ⅱ类水体中，Na+应主要源于钠长石的风化侵蚀，而Ca2+、Mg2+和HCO3-应存在共同的岩石风化来源；之后的水质演化过程中，导致TDS值升高，甚至超标的因素不限于岩石风化，蒸发浓缩和离子交换作用也非常值得关注.③水体中Cl-和SO42-主要来源于海盐源输入，所占比例整体上由西部的Ⅰ、Ⅱ类淡水区向东部微咸水区逐渐增加；然而，Ca2+、K+和HCO3-主要源于地壳源，且Ca2+存在因饱和而沉淀的现象.④人类活动补给的NO3-，受农业化肥污染较弱，仅限于Ⅰ、Ⅱ类和Ⅲ-1（500 mg·L-1-1）类水中；城市污水排放主要作用于Ⅲ类水体，而农业有机肥形成的硝酸盐主要分布在Ⅳ、Ⅴ类水中，即江苏射阳大米主产区内，应是区域生态农业发展的成果之一. |
| 英文摘要 |
| Affected by human activities and climate change, the deterioration of groundwater quality could continue to intensify, and it is difficult to repair after being polluted. In order to reduce the vulnerability of groundwater safety, it is urgent to strengthen research on groundwater quality. To analyze the characteristics of hydrochemical composition and control factors and to explore the impact of human activities, groundwater sampling was conducted in the alluvial and marine plains of Yancheng area, where industrial and agricultural activities were intense. The results showed that:① the TDS value of shallow groundwater was between 211 and 3790 mg·L-1, of which, brackish water samples accounted for 30.28% in Yancheng. The order of the concentration of anions and cations was:HCO3->Cl->SO42->NO3- and Na+>Ca2+>Mg2+>K+. However, from Type Ⅰ/Ⅱ water to Type Ⅴ water, with the increase in TDS value, the dominant anions and cations evolved from HCO3 type to Cl/SO4 type and from Ca type to Na type, respectively. ② In the initial Type Ⅰ/Ⅱ water bodies, Na+ should have mainly originated from the weathering erosion of albite, whereas Ca2+, Mg2+, and HCO3- should have had a common rock weathering source. In the subsequent water quality evolution process, the factors that led the TDS value to increase, or even to exceed the standard, were not limited to rock weathering, and the effects of evaporation-concentration and ion exchange were also very worthy of attention. ③ The enrichment factor analysis showed that the Cl- and SO42- were mainly from the input of sea salt sources, and their proportions were gradually increasing from the freshwater areas of Type Ⅰ/Ⅱ in the west to the brackish water areas in the east. However, Ca2+, K+, and HCO3- were mainly derived from crustal sources, and Ca2+ was precipitated due to saturation. ④ The NO3- derived from agricultural fertilizers was limited to water of category Ⅰ/Ⅱ and Ⅲ-1 (500 mg·L-1-1). Discharge of urban sewage mainly affected Type Ⅲ water bodies. The nitrates formed by agricultural organic fertilizers were mainly distributed in the water of Type Ⅳ and Ⅴ, which was the main rice-producing area of Sheyang, Jiangsu, and the SO42- formed by human activities in this area could be ignored. These should be one of the achievements in the development of regional ecological agriculture. |
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