【摘要】 生态功能区在涵养水源、保持水土、维系生物多样性等方面具有重要的作用。本文以位于南岭生态功能区的流域——武水流域为研究对象,采集流域上游交通运输用地、采矿用地、工业用地、耕地及林地5种土地利用类型土壤样品,分析7种重金属Cd、As、Cu、Hg、Ni、Pb、Zn的含量特征,采用内梅罗综合污染指数评价重金属污染的程度,Hakanson潜在生态风险指数法评价土壤重金属潜在生态风险,并应用主成分分析法探究重金属污染的来源。研究结果显示,武水河上游地区土壤重金属Cd、As、Cu、Hg、Ni、Pb、Zn平均含量分别为1.28、72.44、54.62、0.27、68.32、72.29和158.42mg/kg,均高于土壤背景值,其中采矿用地土壤重金含量除Hg外均高于其他类型土壤。均值状态下土壤中Cd和As单因子污染指数分别为5.07、3.25,其中采矿用地中Cd单因子污染指数可达13.59;土壤重金属综合污染指数表明,采矿用地污染最为严重,其次是工业用地,林地呈安全状态。潜在生态危害指数评价结果显示,采矿用地和工业用地达到了强生态危害,其他类型土壤为轻微生态危害,而采矿用地土壤中Cd达到极强生态危害,As为强生态危害。土壤重金属来源研究结果表明,As、Cd、Cu和Zn来源于矿山开采及工业活动,Ni和Hg主要来源于成土母质,Pb则来源于交通运输。研究认为:武水流域上游区土壤重金属污染情况较为严重,Cd和As是区内主要的风险因子,主要来源于矿山开采以及工业活动。更多还原

【Abstract】 BACKGROUND: Eco-functional areas play an important role in soil and water conservation and biodiversity conservation. The Wushui River is a watershed located in the Nanling ecological function area. However, study on the content and potential ecological risk of heavy metals in the soil of the upstream area of the watershed is scarce.OBJECTIVES: To investigate the degree of heavy metals pollution and the potential ecological risk of soils in the upper reaches of the Wushui River.METHODS: The soil samples of five land utilization types in the upper reaches of the Wushui River Basin, including mining, industrial, and cultivated land and forest, were collected to analyze the contents of seven heavy metals Cd, As, Cu, Hg, Ni, Pb and Zn in the soil. The Nemerow comprehensive pollution index was used to evaluate the degree of heavy metal pollution, and the Hakanson potential ecological risk index was used to evaluate the potential ecological risk of heavy metals in soil. Principal component analysis was used to investigate the source of heavy metal pollution. RESULTS: The results show that the average concentrations of Cd, As, Cu, Hg, Ni, Pb and Zn in the upper reaches of the Wushui River were 1.28, 72.44, 54.62, 0.27, 68.32, 72.29 and 158.42 mg/kg, respectively, which higher than the soil background values. The contents of the heavy metals, except mercury in mining land, were higher than those in other types of soils. The single factor pollution index of heavy metals in the mean state show that Cd and As were heavy pollution elements with factors of 5.07 and 3.25, respectively. In mining land, the Cd single factor pollution index reached 13.59. Heavy metal pollution in mining land was the most serious, followed by industrial land. Forest was in a safe state. Potential ecological hazard index evaluation results showed that Cd reached a very strong ecological hazard and As was a strong ecological hazard in mining land. Mining land and industrial land reached a strong ecological hazard, industrial land reached a moderate ecological hazard, and other types of soils were slightly ecologically harmful. The results showed that As, Cd, Cu and Zn came from industrial and mining activities, Ni and Hg mainly came from parent materials, and Pb came from transportation.CONCLUSIONS: Heavy metal pollution of soil is relatively serious in the upstream area of the Wushui River Basin. Cd and As are the main risk factors in the area, mainly deriving from mining and industrial activities.更多还原