Oral Presentation Society of Environmental Toxicology and Chemistry Australasia 2021

Quantification of selected microplastics in Australian urban road dust (#110)

Stacey O'Brien 1 , Elvis Dartey Okoffo 1 , Cassandra Rauert 1 , Jake W O'Brien 1 , Francisca Ribeiro 1 , Stephen D Burrows 1 , Tania Toapanta 1 , Xianyu Wang 1 , Kevin V Thomas 1
  1. Queensland Alliance for Environmental Health Sciences, The University of Queensland, Woolloongabba, QLD, Australia

Microplastics (1 – 5000 µm) are pervasive in every compartment of our environment. However, little is understood regarding the concentration and size distribution of microplastics in road dust, and how they change in relation to human activity. Within road dust, microplastics move through the environment via atmospheric transportation and stormwater run-off into waterways. Human exposure pathways to road dust include dermal contact, inhalation and ingestion. In this study, road dust along an urban to rural transect within South-East Queensland, Australia was analysed using Accelerated Solvent Extraction followed by pyrolysis Gas Chromatography-Mass Spectrometry (Pyr-GC/MS). Polypropylene, polystyrene, polyethylene terephthalate, polyvinyl chloride, poly (methyl methacrylate) and polyethylene were quantified. Microplastic concentrations ranged from ~0.5 mg/g (rural site) to 6 mg/g (Brisbane city), consisting primarily of polyvinyl chloride (29%) and polyethylene terephthalate (29%). Size fractionation (<250µm, 250 to 500µm, 500 to 1000µm, 1000 to 2000µm and 2000 to 5000µm) established that the <250µm size fraction contained the majority of microplastics by mass (mg/g). Microplastic concentrations in road dust demonstrated a significant relationship with the volume of vehicles (r2= 0.63), suggesting traffic, as a proxy for human movement, is associated with increased microplastic concentrations in the built environment.