广州石化工业区周边农业土壤重金属污染现状与潜在生态风险评价

The Status Quo and Potential Ecological Risks' Assesment of Heavy Metals in Agricultural Soils near a Petrochemical Complex in Guangzhou

采集广州石化工业区周边包括菜地、果园和林地表层土壤（0~20 cm）,分析土壤Zn、Cu、Pb、Cd、Hg和As的含量,利用污染指数和潜在生态风险指数评价了土壤污染状况和潜在生态风险。结果表明,土壤Zn、Cu、Pb、Cd、Hg和As的含量分别为158.6 mg kg-1（19.6~386.1 mg kg-1）,33.6 mg kg-1（3.6~294.3 mg kg-1）,67.1 mg kg-1（25.4~182.1 mg kg-1）,0.22 mg kg-1（0.02~1.00 mg kg-1）,0.61 mg kg-1（0.03~2.40 mg kg-1）和4.40 mg kg-1（0.01~15.50 mg kg-1）。参照中国土壤环境质量二级标准,土壤受到了不同程度的Hg、Zn、Cu和Cd的污染,其中Hg污染最为严重;土壤重金属元素的潜在生态危害性为Hg〉Cd〉Cu〉Pb〉Zn〉As,其中Hg和Cd是主要的生态风险的贡献因子。不同土地利用方式下土壤污染程度和潜在生态风险均为菜地〉果园〉林地。

Surface soils（0-20 cm） were collected from vegetable field,orchard,and woodland around a petrochemical complex in Guangzhou,and the concentrations of Zn,Cu,Pb,Cd,Hg and As in soils were determined,and soil pollution status and potential ecological risk were assessed according to soil pollution index and Hakanson＇s ecological risk index.The results indicated that the concentrations of Zn,Cu,Pb,Cd,Hg and As in soils were 158.6 mg kg-1（19.6-386.1 mg kg-1）,33.6 mg kg（3.6-294.3 mg kg-1）,67.1 mg kg-1（25.4-182.1 mg kg-1）,0.22 mg kg-1（0.02-1.00 mg kg-1）,0.61 mg kg-1（0.03-2.40 mg kg-1） and 4.40 mg kg-1（0.01-15.50 mg kg-1）,respectively.In accordance with standard Ⅱof Environmental Quality Standard for Soils,soils were polluted by Hg,Zn,Cu and Cd to some extent,especially Hg.The order of potential ecological risk for heavy metals was Hg Cd Cu Pb Zn As,while Hg and Cd were dominant contributors for ecological risk.The extent of soil heavy metal contamination and potential ecological risk under different land-use types was vegetable field orchard wood land.