Chengdu Medical College, Chengdu 610500, Sichuan, PR China.
Key Laboratory of Bio-Resources and Eco-Environment (Ministry of Education), College of Life Sciences, Sichuan University, Chengdu 610064, Sichuan, PR China.
Sci Total Environ. 2019 May 15;665:531-537. doi: 10.1016/j.scitotenv.2019.02.034. Epub 2019 Feb 5.
Cadmium (Cd) and lead (Pb) that accumulates in the surface soil of railway rock-cut slopes may migrate to nearby croplands. It is important to determine whether backfill soil type influences the transportation of Cd and Pb in the surface soil. Representative rock-cut slopes, backfill soil of 100% rock fragments, 100% agricultural soil, and 50% agricultural soil and 50% rock fragments (n = 2 for each type) were selected. The pollution and migration levels of Cd and Pb and the soil quality and erodibility were investigated. The soil concentrations of Cd and Pb on the rock-cut slopes were much higher than those of China soil quality standard. Soil erosion was the most important factor that influences the migration of Cd and Pb in the slopes. Increasing the percentage of agricultural soil in the backfill soil resulted in decreasing the diffusion of Cd and Pb by reducing soil erosion. The backfill soil affected the soil quality and erosion durability, which, in turn, affected the transportation of Cd and Pb in the runoff. The soil quality index (SQI) accurately reflects the soil quality and can serve as an indicator of the migration of Cd and Pb on the surface soil of the slopes. Therefore, agricultural soil was more appropriate to use as a backfill soil in slope revegetation practice than was the rock fragment, which was helpful for decreasing the environmental risk of Cd and Pb on the slopes.
铁路岩质边坡表土中积累的镉（Cd）和铅（Pb）可能会迁移到附近的农田。确定回填土类型是否会影响表土中 Cd 和 Pb 的迁移非常重要。选择了具有代表性的岩质边坡、100%岩屑回填土、100%农业土壤以及 50%农业土壤和 50%岩屑（每种类型各 2 个）。调查了 Cd 和 Pb 的污染和迁移水平以及土壤质量和抗蚀性。岩质边坡表土中的 Cd 和 Pb 浓度远高于中国土壤质量标准。土壤侵蚀是影响边坡中 Cd 和 Pb 迁移的最重要因素。增加回填土中农业土壤的百分比会通过减少土壤侵蚀来降低 Cd 和 Pb 的扩散。回填土会影响土壤质量和侵蚀耐久性，进而影响径流中 Cd 和 Pb 的迁移。土壤质量指数（SQI）准确反映了土壤质量，可以作为边坡表土中 Cd 和 Pb 迁移的指示。因此，在边坡植被恢复实践中，农业土壤比岩屑更适合用作回填土，这有助于降低边坡上 Cd 和 Pb 的环境风险。
