中国东南地区偏酸性地下水的分布及影响因素

Distribution and Its Influence Factors of Weak Acidic Groundwater in South East China

地下水酸化可以改变地下水水质、减弱土壤中硝化作用以及引发土壤和地下水的重金属污染。基于1 861组地下水样品p H值和相关水化学分析资料,讨论了东南地区偏酸性地下水的自然分布,分析了影响因素和地下水的酸化现象。结果显示:东南地区偏酸性地下水主要分布在北纬30o 40'以南,地下水p H值与酸雨频率呈显著的负相关关系,和降雨p H值呈显著正相关关系。偏酸性地下水分布区基本与酸雨带重合。地下水p H值与TDS正相关,与Cl-摩尔分数和Al,Ca摩尔比呈负相关关系,表现出酸雨淋滤后的软化现象。典型城市30 a跨度资料显示地下水呈现酸化趋势,酸化过程同时伴随有硝化现象。本研究对正确认识偏酸性地下水分布特征,了解酸雨影响下的地下水酸化趋势,预防地下水酸化污染具有重要意义。

Acidification of groundwater could change the water quality, weaken nitrification in soil and lead to heavy metal pollution in soil and groundwater. Based on the analysis of p H value and the related chemical indexes of 1 861 groundwater samples collected from South East China, the natural distribution characteristics and its influence factors has been discussed. The result showed that the weak acidic groundwater was mainly distributed to the south of N30° 40′. The groundwater p H value has showed negative correlation with the acid rain frequency and positive correlation with the p H value of precipitation. The mainly weak acidic groundwater distribution zone coincides with the acid rain zone. The p H value of groundwater showed positive correlation to TDS, and negative correlations to the percentage of milligram equivalent of Cland the ratio of Al^（3＋） and Ca^（2＋）, which could indicate the softening after the acid rain leaching. The data of typical city with30-year interval confirms the acidification of groundwater. The process of groundwater acidification. This study is extremely important to recognize the distribution characteristic of weak acidic groundwater, the acidification trend of groundwater under the influence of acid rain and the prevention of groundwater pollution caused by acidification.