沈抚污灌区土壤重金属污染潜在生态风险评价

Assessment of Heavy Metal Pollution Using Potential Ecological Risk Indexes in the Shen-Fu Sewage Irrigation Regions

目的评价沈抚污灌区土壤重金属污染的潜在生态风险。方法于2003—2004年,采集了辽宁省沈抚东陵灌区13个自然村的农田土壤样本,并采用地质累积指数法和潜在生态危害指数法对沈抚灌区土壤重金属污染进行潜在生态风险评价。结果沈抚污灌区土壤中的主要重金属污染物是Hg、Cr、Pb、Ni、Cu,其中,Hg的富集程度最高,平均富集系数达到了2.65。地质累积指数法评价结果显示,重金属的污染程度顺序依次为Hg>Pb>Cd>Cu>Ni>As>Cr,整个区域中Hg、Pb、Cd达到了轻度-中等污染水平;潜在生态危害指数法结果显示,重金属的潜在生态危害程度顺序为Hg>Cd>Pb>As>Cu>Ni>Cr,整个灌区土壤重金属污染的潜在生态危害为中等危害水平,其中Hg的生态危害指数已达强度危害。统计分析结果显示,各重金属元素污染之间不存在相关性。结论长期的污灌造成了灌区土壤重金属的严重污染。

Objective To assess the environmental risk of heavy metal pollution in the soil of Shen-Fu sewage irrigation regions. Methods The soil samples were collected from thirteen villages in the Dongling sewage irrigation regions of Liaoning Province from 2003 to 2004.The geoaccumulation index and potential ecological risk index were used to assess the environment risk of heavy metal pollution in the soil of Shen-Fu sewage irrigation regions. Results Hg,Cr,Pb, Ni and Cu were the main pollutants among heavy metals in the soil,and Hg had the highest enrichment index,the average enrichment index value of which reached 2.65. The evaluation result of the geoaccumulation index methods showed that the pollution degree of the heavy metals ranked as follows, Hg〉Pb〉Cd〉Cu〉Ni〉As〉Cr, and the pollution level of Hg, Pb, Cd pollution level reached light-middle. While the results of the potential ecological risk index showed an order of pollution degree ,Hg〉Cd〉Pb〉As〉Cu〉Ni〉Cr. The potential ecological risk index of the whole regions had reached the middle level, and that of Hg had already reached the degree of strong hazard. Conclusion The long-term sewage irrigation has caused serious heavy metals pollution in the soil of irrigation regions.