蚌埠市土壤重金属污染与生态风险评价

Assessment of Heavy Metal Pollution and Potential Ecological Risk of Urban Soils in Bengbu City of China

以蚌埠市土壤重金属污染为研究对象,选取20个采样点,采集表层2～15cm土壤样品,四酸消解后,用火焰原子吸收光谱法测定Cr、Cd、Cu、Pb的含量,三酸消解后,用原子荧光法测定As的含量;分别采用单因子污染指数法、综合污染指数法和潜在生态危害指数法,对蚌埠市土壤重金属污染进行评价。结果表明,土样中Cd、Cr、Pb、Cu和As含量分别在2. 00～8. 00mg·kg^(-1)、47. 25～123. 50 mg·kg^(-1)、5. 50～146. 50 mg·kg^(-1)、3. 75～57. 75 mg·kg^(-1)和0. 13～1. 77 mg·kg^(-1)之间变化,均值分别为4. 64 mg·kg^(-1)、77. 86 mg·kg^(-1)、92. 88 mg·kg^(-1)、20. 51 mg·kg^(-1)和0. 67 mg·kg^(-1),分别为安徽省土壤背景值的55. 41、1. 24、3. 57、1. 06和0. 08倍;各重金属单因子污染指数均值由大到小依次是Cd> Cr> Pb> Cu> As,潜在生态危害程度由大到小依次为Cd> Pb> Cu> Cr>As,土壤重金属污染属重度污染,综合潜在生态危害程度强。可见,蚌埠市土壤重金属污染严重,存在较强的潜在生态危害。

To understand the contamination levels of heavy metals in urban soils of Bengbu city,evaluate their potential ecological harm,and provide scientific references for environmental protection and restoration of heavy metals in Bengbu city.Soil samples were collected in 20 sites of Bengbu city.Chromium(Cr),cadmium(Cd),Copper(Cu),and lead(Pb)in soil samples were tested by flame atomic absorption spectrometry,and arsenic(As)by atomic fluorescence.The single factor pollution index,comprehensive pollution index,and potential ecological harm index were used to evaluate the soil heavy metal pollution of Bengbu city,respectively,in this study.The contents were 2.00~8.00 mg·kg^-1 for Cd(mean:4.64 mg·kg^-1),47.25~123.50 mg·kg^-1 for Cr(mean:77.86 mg·kg^-1),5.50~146.50 mg·kg^-1 for Pb(mean:92.88 mg·kg^-1),3.75~57.75 mg·kg^-1 for Cu(mean:20.51 mg·kg^-1),and 0.13~1.77 mg·kg^-1 for As(mean:0.67 mg·kg^-1),severally.The mean contents of Cd,Cr,Pb,Cu and As in Bengbu soil samples were 55.41,1.24,3.57,1.06,and 0.08 times to the soil background values of Anhui province,respectively.The mean of each single factor pollution index of heavy metals ranged with a high-to-low order of Cd>Cr>Pb>Cu>As,and the potential ecological harm degree presented with the order of Cd>Pb>Cu>Cr>As.In conclusion,the heavy metals pollution in soils was severe,and there was a strong potential ecological harm in urban soils of Bengbu city.