沈哈高速公路两侧土壤重金属污染特征及评价

为探讨高速公路对农田土壤重金属污染的影响，对沈哈高速公路两侧农田60个土壤样品Ph、Cu、Zn、Cd分布状况进行了分析。结果表明，高速公路两侧在距路肩0—320m范围内，Cu、Pb和Zn全量和有效态含量总体上呈现随距离增加而降低的趋势，Cd的变化规律不明显。高速公路两侧的土壤已不同程度出现重金属富集现象，其中Pb属轻度污染且主要集中在东侧距路肩20m处，Cd属重度污染。受研究地点主导风向的影响，高速公路东侧农田土壤的Ph含量明显高于西侧。高速公路旁土壤重金属以Ph、Cd污染为主，污染物主要来源于汽车尾气。

Pollution Characteristics and Assessment of Heavy Metals in Farmland Soil Beside Shenyang-Harbin Super- highway

In order to further understand the effect of superhighway on the heavy metal pollution of farmland soils, sixty soil samples were collected from the arable layer （0-20 cm） of farmland beside the selected section of Shenyang-Harbin superhighway and the contents of Pb, Cu, Zn and Cd were examined. Results showed that both total and available Cu, Pb and Zn concentrations decreased with increasing distance away from the superhighway within 320 m range, while no significant variation principle was observed for Cd. According to the standard of single index grade for farmland soil heavy metal cumulating pollution, the tested soil was slightly polluted by Pb and higher content of Pb occurred in the east 20 m sites away from the superhighway, and was heavily polluted by Cd within the sample range. As affected by the predominant wind direction in the study site, Pb concentration in farmland soil was higher on the east side than on the west side of the superhighway. Both Cd and Pb were identified as the main pollutants, and the exhaust fuel emission from vehicles was considered as the main pollution source leading to the soil heavy metal accumulations.