三峡水库水体几种主要阴离子变化特征

为了了解三峡水库典型阴离子(Cl^-、NO^3-、SO₄^2-)随时间、水位的变化特征，选取三峡水库重庆段长江干流涪陵珍溪、忠县石宝寨和开县长江支流汉丰湖为调查点，每2个月1次，连续1年在调查点设置断面分层采集水样，利用离子色谱仪分析水样中典型阴离子Cl^-、NO^3-、SO₄^2-浓度随时间、水位的变化特征，并初步分析了变化原因。结果表明：全年研究区SO₄^2-浓度为14.67±1.71 mg/L，Cl^-浓度为10.66±4.88 mg/L，NO^3-浓度为1.89±0.15 mg/L，随季节变化差异均较为显著(CV＞43%)，且库区水位变化对干流阴离子含量影响较大；涪陵、忠县和开县各不同采样点之间阴离子浓度变化差异也均较为明显(CV＞40%)。春季总离子浓度（平均为13.02 mg/L）普遍高于其他3季。

Variation Characteristics of Main Anions in Water Bodies of the Three Gorges Reservoir Area

In order to investigate the changing characteristics of concentrations for typical anions （CI-, NOr, and SO42-） along with the variation of time and water level in water bodies of the Three Gorges Reservoir, Fuling, Shibaozhai in Zhongxian, which are located in the main stream of Yangtze River, and Hanfeng Lake, which is located in the Branch of Yangtze River, were selected as study sites. During the whole year, sections were set in investigate spots for stratified water sampling, and CI-, NO3- and SO42- in water samples were continuously monitored by an Ion chromatography once every two months, with the causes of there change being preliminary analyzed. The results showed that the whole year in research area, ion concentration of SO42-, CI- and NO3- were 14.67_＋ 1.71 mg/L, 10.66＋4.88 mg/L and 1.89_＋0.15 mg/L respectively, and they all displayed significant variations along with seasonal change, with a coefficient variation larger than 43%. Meanwhile, the change of water levels at the dam＇ s reservoir had great influence on the content of anions in main stream. Variations of anion concentration in different sampling different, with a coefficient variation larger than 40%. sites between Fuling, Zhongxian and Kaixian were quite The total ionic concentration of reservoir area in spring,an average of 13.02 mg/L, was much higher than that in other seasons.