Tyre wear particles in soils alongside different roads in the Canton of Solothurn

Summary

In Switzerland, 9000 tons of tyre wear particles (TWP) enter the environment every year. This corresponds to over 60 % of the total annual microplastic input (Steiner, 2020). Studies about the emission of TPW are mostly based on model calculations and only few direct measurements of TWP loads in soils exist (Baensch-Baltruschat et al., 2020). This lack of empirical data is partly attributed to the limited availability of generally accessible and standardized extraction and analysis protocols.
The aim of the presented work was the implementation of a method proposed by Grunder et al. (2023) and Foetisch et al. (2023) for the cost-effective analysis of TWP in soils at the Research Institute of Organic Agriculture (FiBL).
60 soil samples were collected from permanent grassland at 15 different road sites and defined distances from the road (1, 2, 5, 10 m) in the canton Solothurn. The analysis of the extracted TWP was performed optically using a Stereomicroscope at 40fold magnification. For the quantification, a colour-based approach using a machine learning pixel segmentation algorithm was used. This poster presents the results of the analysis of the first 20 soil samples.
In the context of my thesis in MAS Environmental Technique and -management at the FHNW, TWP of 20 soil samples from 4 of the 15 sampling areas have been extracted and analysed using the method described above. Numbers of TWP were comparable between sites and particle numbers decreased with increasing distance from the road. The results are presented in this poster