陕北黄土丘陵区农田土壤重金属污染及潜在生态风险评价

Evaluation of Heavy Metal Contamination and Its Potential Ecological Risk to the Farmland Soils in Loess Hilly Area of North Shaanxi Province

通过对陕北黄土丘陵区农田土壤样品的采集、监测,运用地累积指数法和潜在生态风险指数法,重点分析评价了对土壤环境及人体危害较大的重金属元素Cd、As、Cr、Pb的污染程度及其潜在生态风险。结果表明:陕北黄土丘陵区农田土壤重金属处于无污染到中污染状态,污染程度具有Pb>As>Cr>Cd的特征;陕北黄土丘陵区农田土壤重金属处于轻微的潜在生态风险,重金属潜在生态危害由强至弱依次为Cd>As>Pb>Cr;陕北黄土丘陵区农田土壤Pb污染程度较高,主要是由于石油生产运输过程中的Pb排放通过大气沉降进入土壤环境引起的,土壤Pb、As的污染也与人为长期不合理使用含Pb、As农药有关。

The monitored soil samples were collected from farmland soils in loess hilly area of North Shaanxi Province, and this article evaluated the pollution degree and potential ecological risk of heavy metals （Cd, As, Cr and Pb） that could seriously endanger the soil environment and human health by using the geo-accumulation index and potential ecological risk index methods. The results indicated that the soil heavy metals were in a condition of no-to-moderate pollution in loess hilly area of North Shaanxi Province, with the contaminated degree of soil heavy metals of As 〉 Cr 〉 Cd 〉 Pb. The degree of potential ecological risk was in a light level of loess hilly area in North Shaanxi Province, and potential ecological risk of heavy metals in decreasing order was as Cd 〉 As 〉 Pb 〉 Cr. The contaminated degree of Pb in the farmland soil was in a higher condition in loess hilly area of North Shaanxi Province, which is associated with Pb from the production and transportation of oil with atmospheric precipitation into soil environment and the long-term irrational use of pesticides contained Pb and As.