Pollution level and reusability of the waste soil generated from demolition of a rural railway

Railways are typically considered polluted from years of train operation. However, the pollution level of railway in a rural area, which is less exposed to hazardous material from trains and freights, is rarely assessed. This study evaluated common railway pollutants such as heavy metals, total petroleum hydrocarbons (TPHs) and polycyclic aromatic hydrocarbons (PAHs) and their chemical properties in the waste soil generated from the renovation of an old railway in rural area of Wonju, South Korea. Furthermore, lab-scale cultivation tests of peas (Pisum sativum) were performed to assess reusability of the waste soil as a soil amendment. Carbonaceous materials were found in the upper layer of the railway (0 to 40 cm) and the concentration of common railway pollutants was comparable to those of the agricultural land nearby. Specifically, total aromatic and aliphatic TPHs were below detection limit; and total PAHs < 1.0 mg kg(-1) was 1000-times less than railway functional parts. Applying the carbonaceous waste soil improved the water holding capacity of soil by approximately 10% and sprouts formed on the soil with 10% waste soil composition had greater fresh weight, stem length, and root length than the control. Although this investigation was confined to a small length of the railway route, the results confirm environmental safety and the potential value of the waste generated from rural railways for the first time. (C) 2018 Elsevier Ltd. All rights reserved.