(in German)

Background: Railway sleepers impregnated with tar oils (creosote) containing polycyclic aromatic hydrocarbons (PAH) and contaminated soil from industrial wasteland require professional waste management. The maximum workplace concentration (MAK) committee has classified pyrolysis products from organic materials, such as tar oils from lignite and anthracite coal as carcinogens according to category 1. Benzo[a]pyrene (BaP) is used as the reference substance for exposure assessment when working with materials containing PAH. Acceptable and tolerable concentrations of 70 ng/m3 and 700 ng/m³, respectively, are used for the assessment of inhalative exposure according to the technical rule for hazardous substances (TRGS) 910. Dermal uptake of PAH is of particularly high relevance.

Aim: The aim of this study was to check if the acceptable concentrations can be complied with.

Material and methods: Accompanied by consecutive occupational protective measures, air monitoring and biological biomonitoring using 1‑hydroxypyrene (1-OHP) as internal marker were performed in two railway sleeper recycling companies and a thermal soil remediation company.

Results: Workplace measurements showed results exceeding the acceptable and the tolerable concentrations by up to three times for critical tasks. The results of biological monitoring did not correlate with those of air monitoring; however, biological monitoring enabled the efficiency of applied protective measures to be checked. In some cases concentrations of 1‑OHP up to 350 µg/g creatinine were found. At the end of this study most of the results were in the range of the German BAR value (the biological reference value for workplace substances).

Discussion: A successful implementation of the risk-related concept according to TRGS 910 therefore seems to be possible.

Please download the article "Exposure to PAH during recycling of railway sleepers and thermal remediation of contaminated soil" (in German only).