地下水中硝酸盐的含量不仅对水质产生影响，也会显著影响地下水的水化学分类，本文以福建省晋江市为例，对浅层地下水中硝酸盐含量特征及与其他水化学指标的关系进行了分析。结果显示：地下水中硝酸盐绝对含量总体偏高，在阴离子毫克当量百分比中所占比重已超过硫酸盐，对地下水水化学类型产生显著影响。NO3–相对含量较高的样品，往往具有低矿化度，低pH值，高r(Na+)、r(Cl–)比，且属于氯化物型水的特征。利用 r(NO3–)/r(Cl–)可判别地下水在天然条件下的浓缩或稀释效应，亦可结合目标污染物的绝对含量变化，判断其是否属于人为污染抑或天然水动力条件下的浓缩稀释效应。%The content of nitrate in groundwater not only influences water quality but also significantly affects the groundwater hydrochemical classification. An analysis of nitrate content characteristics of shallow groundwater in Jinjiang City shows that nitrate absolute content of groundwater is high and the anion percentage of MEQ proportion has exceeded the sulfate, which has a significant impact on groundwater chemical types. Samples with higher NO3– relative content often have the characteristics of low salinity, low pH, and high r(Na+)/r(Cl–), and belong to chloride water type. r(NO3–)/r(Cl–) can be used as a criterion to judge the water concentration effect or dilution effect under natural conditions, and can also be used to confirm the artificial pollution or concentration effect under the natural hydrodynamic conditions in combination with the change of absolute content of target pollutants.
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