地下水硝酸盐污染特征及其对供水成本的影响研究

Research on the Characteristics of Nitrate Pollution in Groundwater and Its Impact on Water Supply Costs

摘要: 地下水硝酸盐污染已成为威胁饮用水安全和增加供水成本的重要环境问题。本研究以华北某农业灌溉区为对象，通过采集30组地下水样品(覆盖农业区、村庄和河流补给区)，采用紫外分光光度法(HJ 84-2016)测定硝酸盐浓度，结合SPSS 26.0和ArcGIS 10.8进行统计分析、空间插值及主成分分析，量化硝酸盐污染特征及其对供水成本的影响。结果显示：研究区地下水硝酸盐(以$N{O}_3^{-}$ 计)浓度范围为8.7~56.3 mg/L，平均值28.6 mg/L，超标率(GB 5749-2022, ≤10 mg/L)达63.3%，农业区井(均值35.2 mg/L)污染显著高于村庄井(22.1 mg/L)和河流补给井(12.5 mg/L)。主成分分析提取3个主成分(累计贡献率76.8%)，其中农业氮肥施用(贡献率52.3%)和生活污染(25.5%)为主要污染源。成本模型表明，硝酸盐浓度每升高10 mg/L，单位水处理成本增加1.2~2.5元，大型供水厂(5万吨/天)成本较小型厂低30%~40%。研究为农业区地下水污染防控和供水系统经济运行提供了数据支撑。

Abstract: Groundwater nitrate pollution has become an important environmental issue that threatens the safety of drinking water and increases the cost of water supply. This study took an agricultural irrigation area in North China as the object. By collecting 30 groups of groundwater samples (covering agricultural areas, villages and river recharge areas), the nitrate concentration was determined by ultraviolet spectrophotometry (HJ 84-2016), and statistical analysis, spatial interpolation and principal component analysis were conducted in combination with SPSS 26.0 and ArcGIS 10.8 and quantified the characteristics of nitrate pollution and its impact on water supply costs. The results show that the concentration range of nitrate (calculated as $N{O}_3^{-}$ ) in groundwater of the study area was 8.7~56.3 mg/L, with an average of 28.6 mg/L. The over-standard rate (GB 5749-2022, ≤10 mg/L) reached 63.3%. The pollution of Wells in agricultural areas (average 35.2 mg/L) was significantly higher than that of village Wells (22.1 mg/L) and river recharge Wells (12.5 mg/L). Principal component analysis extracted three principal components (with a cumulative contribution rate of 76.8%), among which agricultural nitrogen fertilizer application (contribution rate 52.3%) and domestic pollution (25.5%) were the main pollution sources. The cost model indicates that for every 10 mg/L increase in nitrate concentration, the unit water treatment cost increases by 1.2 to 2.5 yuan. The cost of large water supply plants (50,000 tons per day) is 30% to 40% lower than that of small plants. The research provides data support for the prevention and control of groundwater pollution in agricultural areas and the economic operation of water supply systems.