贺州市西湾街道土壤重金属污染溯源与健康风险评价OA

[Objective]This study took Xiwan Subdistrict of Hezhou City as the research area,systematically collected 213 topsoil samples,and determined the contents of 8 elements including Cu,Pb,Zn,Cr,Ni,Cd,As and Hg,to explore potential heavy metal pollution that may be caused by industrial activities,agricultural production and human settlement.[Methods]Methods such as single pollution index,Nemerow integrated pollution index and human health risk assessment were employed to comprehensively evaluate the degree of heavy metal pollution and associated risks.[Results]The results showed that:(1)The average contents of soil heavy metals in Xiwan Subdistrict ranked in descending order as follows:Zn(134.28×10-6)>Cr(78.84×10-6)>Ni(59.22×10-6)>Pb(44.37×10-6)>As(43.38×10-6)>Cu(41.25×10-6)>Cd(0.71×10-6)>Hg(0.21×10-6).Except Cr,the contents of 7 other elements exceeded the soil environmental background values of Guangxi Zhuang Autonomous Region.(2)The single pollution index assessment indicated that 24%of Cd samples were classified as severely polluted,making Cd the primary pollution factor.The Nemerow integrated pollution index of all samples ranged from 0.41 to 32.94,with moderate and severe pollution accounting for 16%and 27%respectively,confirming the existence of pollution to a certain extent in the study area.(3)Correlation analysis,cluster analysis and PMF model complemented and verified each other,and jointly identified four main heavy metal sources in the study area:Cd and Ni were mainly from industrial sources;Pb,Cr,Zn and Cu were from natural sources;Hg was from domestic sources;and As was from domestic and agricultural sources.(4)The human health risk assessment showed that As was the main non-carcinogenic and carcinogenic factor in the soil.[Conclusions]The heavy metal pollution in the surrounding soils of Xiwan Subdistrict was generally affected by industrial activities.It is recommended to strengthen the monitoring of As and Cd elements to avoid adverse impacts on community health.