新疆“金三角”地区重金属污染及潜在生态风险评价

Assessment of heavy metal pollution and potential ecological risks of soils in the “Golden Triangle”region,Xinjiang

以新疆"金三角"地区为研究对象,采集156份土壤样品,对土壤中6种重金属进行测定,采用土壤重金属富集系数和潜在生态风险指数对污染状况进行分析,运用相关性、地统计学和GIS技术对重金属空间分布和来源进行研究.结果表明,研究区土壤重金属Cu、Zn、Cd、Pb、As、Ni的平均含量分别为54.44、107.18、0.76、21.78、17.32、40.63 mg·kg^(-1).富集系数结果表明Cd呈现中度富集,其余重金属为轻度富集.研究区土壤重金属潜在生态风险指数平均值为230.87,呈现为较高生态风险,Cd是最主要的生态风险因子.分析空间分布图和污染来源结果表明,研究区中东部重金属Cu,Zn,Pb和As含量较高,工业活动和城市人类活动是其主要来源;研究区西南部Ni含量较高,采矿和母质风化是其主要来源;Cd主要分布在研究区西南部和东北部,主要来源可能是农药、化肥的大量使用,地膜的广泛应用以及采矿产生的粉尘.

One hundred and fifty six soil samples were collected from the ＂Golden Triangle＂region in Xinjiang and analyzed for concentrations of Cu,Zn,Cd,Pb,As and Ni. In addition,enrichment factors（ EF） and ecological risk index（ RI） were employed for metal pollution and ecological risk assessment,respectively. Correlation analyses,Geostatistical and GIS technology were used to make the spatial distribution maps and identify the sources of metal pollution. The results showed that the mean values of Cu,Zn,Cd,Pb,As and Ni were 54. 44,107. 18,0. 76,21. 78,17. 32 and40.63 mg·kg^-1,respectively. The results of EF showed that Cd fell into the moderate enrichment group; other metals fell into the minor enrichment group. The mean value of RI was 230.87 in soil,indicating high ecological risk,and Cd was the key factor for the metal pollution in soil. The spatial distribution maps and the metal pollution sources showed that Cu,Zn,Pb and As in the mid-east part of the study area were polluted by industrial activities and urban human activities; The high values of Ni were found in the southwest area,and mining and weathering of parent rock were the main sources of Ni. Cd was widely distributed in the southwest and northeast parts of the study area and may be attributed to pesticide,chemical fertilizer and the widely use of plastic film.