Study On The Influence Of Newly Built Lead-battery Agglomeration Area On The Characteristics Of Heavy Metals In The Surrounding Soil

Battery manufacturing is an important part of new energy industry and one of the basic industries for developing strategic emerging industries.It occupies an important position in China’s national economic construction.However,along with the process of industrialization,there will be modern environmental problems,so the reformation of the industry is an indispensable part of the sustainable development.In this study,a new lead-acid battery agglomeration area in a county of northern Zhejiang after upgrading was taken as the research object,and the investigation of its impact on the surrounding soil environment after six years of operation was carried out,in order to provide scientific basis for the prevention and control of heavy metals and the sustainable development of the industry.173 samples of surface soil around the lead-acid battery agglomeration area were collected and the contents of Hg,As,Cu,Zn,Pb,Cd,Ni,and Cr in the soil were determined.This method that contained the single factor index,Nemero comprehensive index and potential ecological risk index was used to evaluate soil environmental quality,then for the heavy metals that are enriched in the soil,the risks to human health was evaluated by human health risk assessment model.In addition,the spatial distribution characteristics of heavy metals were studied by spatial interpolation and spatial autocorrelation analysis.Finally,the sources of heavy metals were determined by multivariate statistical analysis,including correlation analysis,stepwise regression analysis and principal component analysis.The main findings are as follows:（1）Among the 8 soil heavy metals,the average contents of As(8.42 mg kg^-1),Zn(120.88 mg kg^-1),Pb(53.67mg kg^-1),and Cd(0.26mg kg^-1)were higher than the regional mean background values,its points accounted for 40.46%,65.32%,69.36%,and 54.91%,respectively.The soil showed a state of enrichment dominated by the four elements;Cu,Zn,Pb,and Cd existed at points that exceed the screening value of agricultural land soil pollution risk（GB 15618-2018）,accounting for 4.05%,8.09%,9.83%,and 30.06%,respectively,but the average content of each element is lower than that standard limit.（2）Based on the screening of agricultural land soil pollution risks,the single factor index（P_i）of heavy metals on the soil was less than 1,the potential ecological risk index（E_rⁱ）of single metals was less than 40,and the Nemerow comprehensive index(P_sum=0.69)was less than 0.7,the total potential ecological risk index of multi metals（RI=40.04）was less than 110,that was to say,the environmental condition of soil was within the safe range;The exceeding rate of Cu,Zn and Pb was less than 10%,all of which were light pollution points.The exceeding rate of Cd was more than 30%,of which the proportion of moderate pollution points was more than 10%,and there were more than moderate ecological risk points.The other 7 elements were all at slight ecological risk points,that was,Cd was the main element affecting soil quality in the study area;Taking P_sum and RI as the research objects,it was found that more than 40%of the sampling points were above the alert level,and scattered points were at moderate level of ecological hazard.（3）In terms of non-carcinogenic and carcinogenic risks,the risks of four soil heavy metals（As,Zn,Pb and Cd）on human body through hand-to-mouth ingestion,skin contact and respiratory inhalation were negligible.The two risk rates of hand-to-mouth ingestion were higher in children than in adults,and opposite in skin contact,while the former was higher in children than in adults under breath inhalation,while the latter was opposite;As was the main element that caused non-carcinogenic and carcinogenic risks to children and adults,hand-to-mouth ingestion was the main source that affected human health,followed by skin contact and respiratory inhalation.（4）Hg decreased gradually from the outside to the inside on the whole,which was mainly related to natural factors and was only affected by man-made sources at the edge of the study area;As was significantly affected by the characteristics of single point in space,and its distribution was scattered.It was mainly affected by geological processes such as ore weathering and industrial activities;The high value area of Cu was mainly located in the southeast to northwest axis,but the influence degree of man-made pollution source was small.Cu was locally affected by industrial and agricultural activities;The content of Zn in most areas was higher than the background value,which was mainly affected by industrial and agricultural activities;The high value area of Pb was mainly distributed near the lead-acid battery agglomeration area and the southwest and southeast corner of the research area,but most areas were not affected,which was affected by some lead-acid battery enterprises and regional agricultural activities;The distribution of Cd and Pb was similar,but the autocorrelation scale of Cd was larger than that of Pb,which was mainly affected by the compound source of industrial and agricultural sources;The contents of Ni and Cr in the whole study area were almost all lower than the background value,and neither of them showed significant spatial characteristics,mainly from natural factors.（5）After six years of operation,only some of the enterprises in the new lead-acid battery agglomeration area have affected Pb and Cd,and the diffusion distance was not large,which showed that the technology improvement of the industry has made some achievements in heavy metal emission reduction.If the supervision and the environmental awareness of the enterprise can be strengthened,more significant results will be seen.Meanwhile,it also shows that this regulation method can provide a good reference for the promotion and transformation of the old battery factories or agglomeration areas,which is conducive to promoting the sustainable development of the lead battery industry and maintaining and protecting the soil environmental quality of the region.