Research Plan for Combination of X-ray Dispersive Fluorescence Spectrometer and Inspection Vehicle to Screen Harmful Chemical Species on Railroad Tracks (R5)

초록

To quickly find hot spots where the ground is contaminated with harmful or dangerous chemical species, screening methods applicable to railroad tracks have been developed by Railway Technical Research Institute (RTRI). For heavy metals, an X-ray dispersive fluorescence spectrophotometer (XRF) has been devised to determine these elements including cadmium, lead, selenium, mercury, arsenic and chromium on railroad tracks on site in a short time or five minutes. Basically, it is not easy to apply XRF analysis to soil samples, which are not dry sometimes. In this manner to use XRF for soil samples collected from railroad tracks, a simple way has been developed to rapidly dry soil samples before applying XRF analysis to the sample. This effort enables screening railroad tracks to confirm the location of hot spots polluted with such heavy metals. In the meanwhile, an inspection vehicle has been developed separately by Korea Railroad Research Institute (KRRI) to easily collect soil samples directly from railroad tracks, which is equipped with a probe to drill the ground and sample soil as well as analytical instruments to analyze the sample in the vehicle on site. This vehicle enables soil sampling on railroad tracks wherever needed and determining pollutants immediately thereafter. However, there will be a limit to load all analytical instruments on the vehicle and prepare time to analyze. This is because the analytical manner is based on techniques for laboratory use which would take a long time. Furthermore, the vehicle shall be run between trains on service lines, which is sometimes a short interval or a few minutes. The sample shall be put in a treatment process before applying it to such analytical technique. It would take at least one hour or longer for each sample. Thus, quick and simple analytical ways are also desired for the analysis on the vehicle. To enhance both the technologies to quickly analyze soil samples or easily collect them on site from the ground, a combination of the XRF detection system and inspection vehicle is planned. At this seminar, the performance of the XRF analysis and an outline of the inspection vehicle will be shown. The plan for assembling the technologies will also be discussed. Basically, a simple test is to be planned to optimize the analytical condition using the XRF equipment for its application to railroad track, in which the chemical condition of the soil must be different from those of soils present at places where human-being activity is normally performed. The equipment should be brought to railroad tracks to directly apply it to the actual soil in tracks. As is to be expected, high concentrations of lead might interfere with the determination of arsenic, if any. In case it is hard to quickly dry soil samples after collecting them from railroad tracks, this would also adversely affect the accuracy of analysis. In railroad tracks, inhomogeneous soil samples are expected. Furthermore, it would be difficult to simply collect samples avoiding large size soil particles. These inconvenient conditions should thoroughly be checked in railroad track investigations. After confirming the XRF detector performance for soil samples from railroad tracks, loading the detector on the inspection vehicle is planned. This process can make sure of the XRF detector performance and secure the detector application to the vehicle step by step. One of the goals in this research work is to develop inspection systems for railroad pollution. Furthermore, remediation of polluted railroad tracks will easily be planned with the data to be given by this inspection system.