Traffic-related microplastic particles, metals, and organic pollutants in an urban area under reconstruction

Ida Järlskog; Ann-Margret Strömvall; Kerstin Magnusson; Helén Galfi; Karin Björklund; Maria Polukarova; Rita Garção; Anna Markiewicz; Maria Aronsson; Mats Gustafsson; Malin Norin; Lena Blom; Yvonne Andersson-Sköld

doi:10.1016/j.scitotenv.2021.145503

Traffic-related microplastic particles, metals, and organic pollutants in an urban area under reconstruction

Sci Total Environ. 2021 Jun 20:774:145503. doi: 10.1016/j.scitotenv.2021.145503. Epub 2021 Feb 7.

Authors

Affiliations

¹ VTI, Swedish National Road and Transport Research Institute, SE-581 95 Linköping, Sweden; Geology and Geotechnics, Department of Architecture and Civil Engineering, Chalmers University of Technology, SE-412 96 Gothenburg, Sweden. Electronic address: ida.jarlskog@vti.se.
² Water Environment Technology, Department of Architecture and Civil Engineering, Chalmers University of Technology, SE-412 96 Gothenburg, Sweden.
³ IVL, Swedish Environmental Research Institute, Kristineberg, SE-451 78 Fiskebäckskil, Sweden.
⁴ Sustainable Waste and Water, City of Gothenburg, SE-424 23 Gothenburg, Sweden.
⁵ Kerr Wood Leidal Associates Ltd., 200 - 4185A Still Creek Drive Burnaby, British Columbia V5C 6G9, Canada.
⁶ VTI, Swedish National Road and Transport Research Institute, SE-581 95 Linköping, Sweden.
⁷ Engineering and Sustainability, NCC Infrastructure, NCC, SE-405 14 Gothenburg, Sweden.
⁸ Urban Transport Administration, City of Gothenburg, SE-403 16 Gothenburg, Sweden.
⁹ Water Environment Technology, Department of Architecture and Civil Engineering, Chalmers University of Technology, SE-412 96 Gothenburg, Sweden; Sustainable Waste and Water, City of Gothenburg, SE-424 23 Gothenburg, Sweden.
¹⁰ VTI, Swedish National Road and Transport Research Institute, SE-581 95 Linköping, Sweden; Geology and Geotechnics, Department of Architecture and Civil Engineering, Chalmers University of Technology, SE-412 96 Gothenburg, Sweden.

PMID: 33609838
DOI: 10.1016/j.scitotenv.2021.145503

Abstract

In urban environments, particularly areas under reconstruction, metals, organic pollutants (OP), and microplastics (MP), are released in large amounts due to heavy traffic. Road runoff, a major transport route for urban pollutants, contributes significantly to a deteriorated water quality in receiving waters. This study was conducted in Gothenburg, Sweden, and is unique because it simultaneously investigates the occurrence of OP, metals, and MP on roads and in stormwater from an urban area under reconstruction. Correlations between the various pollutants were also explored. The study was carried out by collecting washwater and sweepsand generated from street sweeping, road surface sampling, and flow-proportional stormwater sampling on several occasions. The liquid and solid samples were analyzed for metals, polycyclic aromatic hydrocarbons (PAH), oxy-PAH, aliphatics, aromatics, phthalates, and MP. The occurrence of OP was also analyzed with a non-target screening method of selected samples. Microplastics, i.e. plastic fragments/fibers, paint fragments, tire wear particles (TWP) and bitumen, were analyzed with a method based on density separation with sodium iodide and identification with a stereo microscope, melt-tests, and tactile identification. MP concentrations amounted to 1500 particles/L in stormwater, 51,000 particles/L in washwater, and 2.6 × 10⁶ particles/kg dw in sweepsand. In stormwater, washwater and sweepsand, MP ≥20 μm were found to be dominated by TWP (38%, 83% and 78%, respectively). The results confirm traffic as an important source to MP, OP, and metal emissions. Concentrations exceeding water and sediment quality guidelines for metals (e.g. Cu and Zn), PAH, phthalates, and aliphatic hydrocarbons in the C₁₆-C₃₅ fraction were found in most samples. The results show that the street sweeper collects large amounts of polluted materials and thereby prevents further spread of the pollutants to the receiving stormwater.

Keywords: Micro-litter; Road dust; Stormwater pollutants; Street sweeping; Tire wear particles.