基于地统计技术的地下水硝酸盐的污染源解析研究

Sources Apportionment of Groundwater Nitrate Using Statistical Technology

为研究郑州市中牟县地下水硝酸盐的污染机制,该文于2020年6-8月采集了该地区地下水样品93组,联合应用水化学理论、多元统计技术和地统计技术等手段,分析了该区域内地下水硝酸盐的空间变化特征和污染机理,识别了地下水中硝酸盐的污染来源。结果表明:中牟县地下水中NO_(3)^(-)浓度范围介于0.20~338 mg/L,均值是42.4 mg/L,有19.4%的样品超出了地下水质量标准的Ⅲ类标准(88.6 mg/L),表明该地区地下水已经受到人类活动的显著影响。土地利用类型对中牟县地下水中硝酸盐浓度有显著影响,表现为湿地地下水中硝酸盐的平均浓度(0.511 mg/L)显著低于农业用地(61.7 mg/L)和住宅用地(43.8 mg/L)。地下水硝酸盐的空间分布特征表现为沿地下水流向,硝酸盐的浓度逐渐增加。中牟县北部地区,受到黄河河水的稀释,地下水硝酸盐浓度较低,水质较好,而研究区的东部和南部,由于受到农业活动的强烈影响,地下水水质较差。中牟县地下水硝酸盐的主要污染来源是生活污水和农业施肥,基于GIS空间插值分析可将源解析结果呈现在区域上,为地下水水环境保护提供空间数据支撑。

In order to identify the pollution mechanism of nitrate in Zhongmu County,Zhengzhou City,a total of 93 groups of groundwater samples were collected in June-August,2020.The spatial distribution,pollution mechanism and pollution sources of nitrate in groundwater were identified by combining the water chemical,multivariate statistical technology and geostatistical technique.The results showed that the mean concentration was 42.4 mg/L(range from 0.20 to 338 mg/L)and there were 19.4%samples concentration exceeded quality standard in China(88.6 mg/L),therefore,the groundwater has suffered serious effect from human activities.There were significant differences between the mean levels of nitrate resulting from the different land use,and showed that the mean concentration of nitrate in wetland(0.511 mg/L)was significant lower than in agriculture land(61.7 mg/L)and residential land(43.8 mg/L).The spatial distribution of nitrate in groundwater shows that the concentration of nitrate increases gradually along the groundwater flow direction.The northern part of Zhongmu County was diluted by the Yellow River,resulting in lower nitrate concentrations and better water quality,while in the eastern and southern parts of Zhongmu County,the groundwater quality was poor due to it was affected by agricultural activities.The mainly sources of NO_(3)^(-)pollution was the domestic sewage and chemical fertilizer in the study areas.Based on GIS spatial interpolation analysis,the source analysis results can be showed in the region,which can provide spatial data support for groundwater environmental protection.