Health Assessment of Heavy Metals in Roadside Soils at Different Operation Time: A Case Study of Zhengzhou-Shangqiu Section Along the Lianyungang-Horgas Highway
基于不同通车时间的路旁土壤重金属健康风险:以连霍高速郑州—商丘段为例

Two sample transects of Wanliu and Xiaowangzhuang on the Zhengzhou-Shangqiu section along the Lianyungang-Horgas highway were chosen to investigate the health risks of heavy metals (Cd, Cu, Pb, Zn, Ni and Cr) in roadside soils. Wanliu transect was opened in 1994, and Xiaowangzhuang in 2001.Mixed topsoil samples (0-15 cm) were collected at 0, 5, 15, 25, 35, 50, 100, 200, 300 and 1500 m from the highway. Concentrations of soil heavy metals were measured with the method of AAS. Based on the health risk models recommended by US EPA, noncarcinogen and carcinogen health risks of soil heavy metals were evaluated. The results showed that the heavy metal concentrations and the health risks increased with the increase in operation time, indicating that the operation time might play a decisive role in heavy metal accumulations in roadside soil. Both the heavy metal concentrations and their health risks showed skewed distribution or cubic polynomial distribution with the distance from the highway roadbed. The highest concentration and the highest health risk occurred between 15-50 m from the highway roadbed. HQ and HI at bothsampling sites were lower than 1, which meant that there was no non-carcinogen risk. CRCrand TCR at both sample sites were beyond the standard suggested by US EPA, which meant there was possibly carcinogenic risk, but lower than the lenient standard raised by some other experts (10-6-10-4). The contribution rate of CRCrto TCR reached 97.83%, and Cr was the major carcinogen risk factor.