新乡市农村浅层地下水健康危害及污染源识别

Health risk assessment and the pollutant source identification of the shallow groundwater in Xinxiang rural areas

应用健康风险评价模型和多元统计方法,对河南省新乡市农村地区浅层地下水2015年11月的水质数据(30眼地下水监测井,15个水质指标)进行分析,评估了对当地农村人口造成的健康风险,探索污染物的空间分异特征,并识别对应污染源。结果表明:30眼监测井的Cr6+、Pb、Cd、Hg、As指标均满足Ⅲ类地下水水质标准,但有29眼监测井存在超标因子,浅层地下水污染形势严峻;污染物通过饮水途径所致健康风险均大于可接受风险水平(1×10-6),浅层地下水不适宜直接饮用;监测井可以划分为A组、B组、C组,A组水体受到原生地质污染、营养污染和盐类污染的共同影响,B组受有机污染、盐类污染影响,C组受原生地质污染、盐类污染、营养污染、有机污染的多重作用。

The paper has done an investigation of the contamination status-in-situ of the shallow groundwater in November 2015 in Xinxiang rural areas by selecting 30 groundwater samples respectively and independently from the 30 villages in the city suburbs,and examined and checked them by using 15 parameters（ CODMn,NH＋4-N,Cr6 ＋,F-,VP,CN,Pb,Cd,Fe,Mn,Hg,As,TH,SO2-4,Cl-） for all the samples. For the research purpose,we have first of all done a single-index evaluation analysis for the monitoring results in the paper. The health risks have been assessed through the US EPA health risk assessment model on the basis of the exposure parameters of the pollutant particles in Henan rural areas. And,then,we have adopted the multivariate statistical techniques,including the cluster analysis,discriminant analysis and the factor analysis in the paper in hoping to make out and clarify the spatial characteristics and the corresponding sources of the groundwater pollutants in the shallow aquifer in the city. The results demonstrate that： among the five indexes of the aforementioned five aspects,including Cr6 ＋,Pb,Cd,Hg and As,the groundwater quality can only meet the 3 rd level of water quality standard（ GB/T 14848—1993）,whereas the five indexes of the aforementioned five aspects from the 29 kinds of samples of the water samples gained from the monitoring wells have been found exceeding the standard indexes. More seriously speaking,on the whole,the health risks caused by the pollutants found from the drinking water samples prove to be significantly higher than the utmost allowable level recommended by ICRP（ 1 × 10-6）,among which,Cl-turns out to be the chief pollution contributor.Thus,it can be seen that the shallow groundwater in the areas under investigation is not fit for drinking directly. Furthermore,the30 monitoring wells under investigation can be divided into three groups,group A,group B and group C,by using the cluster analysis method（ CA）,with the water pollutant samples presented in the said three groups separately for the spatial difference. The results of the constituent factors analysis（ FA） show that： When the FA is applied to the data sets of the 3 groups,the testing results gained from the 3,2 and 3 latent factors have been found accounting for 86. 729%,74. 658% and 92. 451% of the total variance. The contamination situations can be stated as follows：For group A,due to the effects made by the local natural geologic environment,the nutrient pollution and salty pollution have been found being the chief contaminants,whereas,for group B,the water pollutants have been identified more likely from the organic pollutants and salty pollutants. As to group C,the natural geologic environment,the salty pollution,the nutrient pollution and the organic pollution can all make their own individual or mixed effects.