2014—2019年某市农村地区自备井水中硝酸盐含量及影响因素分析

Content of Nitrates and Its Influencing Factors in Well Water in Rural Areas of a City, 2014—2019

目的了解某市农村地区自备井水中硝酸盐含量特征,为改善农村饮用水水质提供科学依据。方法 2014—2019年,在某市的4个涉农区,分别于枯水期和丰水期采集自备井水厂的出厂水和末梢水,测定其硝酸盐浓度。用t检验和方差分析比较自然对数转换后的硝酸盐浓度在不同年份、区域、水期类型和水源类型之间的差异。结果共采集水样2 787份,水样中硝酸盐的中位数为3.70 mg/L,达标率为84.71%,不同年份、区域、水期类型和水源类型水样中硝酸盐水平的差异均有统计学意义(P<0.05)。2017年硝酸盐浓度水平最高,2014年最低。在所研究区域中,东南部区域的水样中的硝酸盐水平较西北部高,丰水期水样中的硝酸盐水平较枯水期高,浅井中的硝酸盐水平较深井高。结论年份、区域、水期类型和水源类型均是影响某市农村地区自备井水中硝酸盐水平的重要因素。针对硝酸盐含量过高地区应实施优先改水措施并加强水质卫生监测和水源保护。

Objective To investigate the characteristics of nitrate content in well water in rural areas of a city, and to provide a scientific basis for improving rural drinking water quality. Methods From 2014 to 2019, samples of finished water and terminal water were collected from wells in four rural areas of the city during both dry season and wet season, and the concentration of nitrates was determined. The t-test and an analysis of variance were used to investigate the differences in nitrate concentration after logarithmic transformation among different years, regions, water periods, and types of water source. Results A total of 2 787 water samples were collected, with a median nitrate concentration of 3.70 mg/L and a rate of reaching the standard of 84.71%. There were significant differences in nitrate concentration among different years, regions, water periods, and types of water source(P <0.05), with the highest nitrate concentration in 2017 and the lowest nitrate concentration in 2014. For the regions analyzed, the water samples in southeastern regions had a significantly higher nitrate concentration than those in northwest regions;the water samples in wet seasons had a significantly higher nitrate concentration than those in dry seasons;the water samples from shallow wells had a significantly higher nitrate concentration than those from deep wells. Conclusion Year, region, water period, and type of water source are important influencing factors for nitrate concentration in well water in rural areas of the city. For areas with a high nitrate concentration, priority should be given to the reform of drinking water, and water quality monitoring and water source protection should also be strengthened.