婺源景区旅游公路两侧重金属横向变异分析与评价

以婺源景区车流量最大的东线旅游公路为研究对象,并以车流量少的浙源-庐坑路段土壤为对照样。通过合理布样、精确检测以及风险评价,确定旅游公路沿线重金属Cu、Pb、Zn、Cd分布状况和污染程度。结果显示:鹤西-李坑、晓起-江岭、汪口-江湾、江湾路段沿横向变化情况为重金属含量随着横向距离的增加而下降,其峰值位于距路基0 m或5 m处,受地形、风向的影响,导致各个路段部分测点某些重金属左侧含量高于右侧,或者右侧高于左侧,且各个路段的分割点不同;公路土壤重金属分布受自身和外在因素综合作用的程度不同,故各个路段Zn、Cd、Pb、Cu超标范围不同;采用潜在生态风险指数法对四个路段的评价结果为潜在生态危害最大的重金属是Cd,等级为强,综合潜在生态危害最大的是江湾路段,等级为中等,需要指出的是,Cu的污染系数和超标范围为四个重金属之最,其危害也应不容忽视。

Lateral Variation Analysis and Evaluation of Heavy Metals in Roadsides of Wuyuan Scenic, China

We selected eastern tourist road of Wuyuan Scenic, China with the largest traffic flow as study object,and chose Zheyuan-Likeng section with the smallest traffic flow as the contrast. Cu, Pb, Zn, and Cd distributions and extent of contamination were determined by rational sampling, detection and risk assessment. Results include the following three respects. (1) Heavy metal contents decrease with increasing lateral distance, and the four sections with peak values are 0 m or 5 m away from roadbed,as Hexi-Likeng section, Xiaoqi-Jiangling section, Wangkou-Jiangwan section, and Jiangwan section. Certain heavy metals in left side are higher than the right side at different measuring point of each section, inflected by terrain and wind direction; (2) Zn, Cd, Pb, and Cu in each section are different at the scope exceeding the local background values because integrated internal and external factors influencing distribution of heavy metals in roadside soil are different; We adopted potential ecological risk index to evaluate pollution condition of four sections. Result show that Cd has the highest potential ecological risk,and Jiangwan section has the highest integrated potential ecological risk. The risk of Cu should not be overlooked as the pollution coefficient and scope of Cu exceeding the standard mostly in the four heavy metals.