连霍高速郑商段路旁土壤重金属积累及潜在风险

以连霍高速郑商段不同通车时间的湾刘（通车11 a）和小王庄断面（通车4 a）为研究对象，根据距离公路远近不同布设土壤采样点，用原子吸收分光光度法测定土壤Cd、Cu、Pb、Zn、Ni和Cr含量.在计算表层土壤重金属积累速率和通量的基础上，探讨了路旁土壤重金属的分布特征、积累状况及潜在污染风险.结果表明，Cu、Pb和Cd是典型的交通源重金属，其含量在公路两侧随距离的增加呈先增加后减少的趋势，含量峰值出现在离路基25～50 m之间.湾刘断面土壤Pb、Cd、Cu的平均含量分别为14.52、 1.32、 73.54 mg·kg^-1，小王庄断面分别为12.41、 0.98、 43.64 mg·kg^-1.大部分样点Pb、Cu和Cd的积累速率和通量为正值，且Cu>Pb>Cd，小王庄断面大于湾刘断面. 2个断面土壤Cd已经发生污染；Cu的潜在污染风险在百年时间尺度之内，大部分样点在未来5～30 a中可能发生污染，潜在风险大；Pb的潜在污染风险都在千年尺度以上，潜在风险极小.

Accumulation and Potential Risk of Heavy Metals in Roadside Soils Along the Section of Zhengzhou-Shangqiu,Lianyungang-Huoerguosi Highway

Two typical sampling transects along the Zhengzhou-Shangqiu section,Lianyungang-Huoerguosi highway,were chosen to investigate the accumulation of heavy metals in roadside soils.The highway section at Wanliu transect has been operated since 1994,and that at Xiaowangzhuang section since 2001.Soil samples were collected along the two transects according to the distances from the highway.In laboratory,the concentrations of Cd,Cu,Pb,Zn,Ni and Cr in the soils were measured using AAS.The accumulation of these meta...