Pollution Assessment And Health Risk Assessment Of Rare Earth Elements In Soil Of Ebinhu Watershed

As a important environmental factor,soil is the indispensable important part of human existence,in recent years,due to the rapid development of urbanization and industrialization process,lead to many settlement or discharge pollutants containing rare earth elements in soil,these pollutants can through the food chain finally enter human body,cause a harm to human body,The pollution problem of rare earth elements has gradually attracted the attention of scholars at home and abroad.In this paper,the rare earth elements in the soil of Ebi Lake Basin were taken as the research object.Firstly,the content characteristics of rare earth elements were analyzed by combining geo-statistics and mathematical statistics.Then,the pollution characteristics of rare earth elements were evaluated and analyzed by using geoaccumulation index method and potential risk index method.Finally,the health risk model was used to evaluate the health risk of rare earth elements in the soil of the study area,and the risk early warning was made by using the Hessen probability curve.The specific results are as follows:(1)in the study area in the soil in the ebinur lake basin of five kinds of rare earth element descriptive statistics analysis,it is concluded that Gd,Er,two kinds of rare earth element background value is higher than the average of xinjiang,Sm,Sc and Y three rare earth element background values is less than the average of xinjiang,but the Sc and Y the maximum and the minimum concentration of two kinds of elements is large,There are many high value areas in the study area.According to the inverse distance interpolation diagram,the high value areas of the five elements are mainly concentrated in the confluence of Ebi Lake and Kuitun River,the middle and upper reaches of Boltala River,the middle and lower reaches of Raba Bay and most areas of the lower reaches of Kuitun River.(2)According to the average geoaccumulation index of the five rare earth elements,the geoaccumulation index is at the level of zero pollution,and 2.5%,3.1% and 1.9%of the sampling sites of Gd,Er and Sm are at the level of two moderate pollution,respectively.According to the analysis of single item potential ecological risk index,GD,ER,SM and SC had a few points with high 2-level risk,while most of the other points were at the level of 0 and 1 slight risk.According to the comprehensive potential ecological risk,it can also be analyzed that most of the points are at level 0 and 1 with slight risk,and a few of the points with high risk are at level 2.(3)Through experiments and data processing,the average value of rare earth elements in wheat,maize and soybean were 9.53μg/kg,7.62μg /kg and 9.18μg /kg,respectively.By the health risk assessment model and comparison with the control area can be concluded that studies in different sex,different age of the crowd every day in the intake of rare earth elements content in crops is lower than the control area,the intake of rare earth elements are lower than the daily intake(ADI)value,and through the calculated results can be seen that EDI value and decreased with the increase of age.In particular,it can be seen that the EDI of children aged 2-12 is higher than that of other populations,while the EDI of people aged over 13 does not change much,and the results are similar to those of the control area.The average daily exposure of children and adults through the digestive tract,respiratory tract and human skin was calculated,and the results showed that the average daily exposure of children and adults through the three ways was lower than the allowable value,which was considered as a healthy state.(4)Through enrichment factor analysis,it can be found that the enrichment factors of Gd and Er have a large range of variation.The samples with slight enrichment of Gd level 1 account for 92.73%,and those with moderate enrichment of Gd level 2 account for 0.6%.6.67% of the samples come from soil sources,and 0.7% of the samples show that Gd comes from soil sources and human sources.The results indicate that Gd element is slightly enriched to moderately enriched.According to the enrichment factor analysis,the proportion of slightly enriched samples in level 1 was 75.8%,and that in level 2 was 1.8%.22.4% of the samples came from soil sources,and 1.8% of the samples showed that Er came from soil sources and anthropogenic sources,which indicated that Er was slightly enriched to moderately enriched.Most of the sample sites of Sm and Y elements were in the non-enrichment state,and the preliminary conclusion was that the five elements were mainly mixed by natural sources and anthropogenic sources.Correlation studies show that Sc,Gd and Y may have similar sources.The correlation coefficients between ER and Gd,Sc and Y are all small,indicating that ER element is relatively independent.The study of Hessen probability curve shows that the pollution superposition of Er element is more serious.