Vehicles are unique indoor environments, with interiors dominated by plastic/synthetic materials and exposure to extremes of temperature and radiation, leading to substantial potential for emissions of plastic additives from vehicle materials and subsequent exposure to drivers and passengers. Flame retardants (FRs) and per- and polyfluoroalkyl substances (PFAS) were measured in 30 dust samples collected from dashboards, seats, and trunks of cars of the same make and model (year of manufacture 1996-2021) to evaluate levels in dust and time patterns in additive use across cars of different ages. PFAS were detected in all dust samples at low levels, while FRs were detected in all samples, with some compounds consistently exceeding µg/g levels, especially tris(1,3-dichloro-2-propyl) phosphate (TDCIPP) and decabromodiphenyl ether (BDE-209), substantially higher than in other indoor environments. Although cars were of the same model, large variations were observed in FR concentrations in dust between cars, emphasizing the challenge in generalizing FR exposures from vehicle dust. Concentrations of BDE-209 in vehicle dust did not decrease over the 1996-2021 period, suggesting that restrictions on DecaBDE have had limited impact, likely due to exemptions in regulations for the automotive industry. The high FR levels indicate ongoing use of both organophosphate and brominated FRs in vehicles on the European market, although flammability standards for interior car materials are not mandated by European regulations, and the continued presence of long-restricted FRs suggests the presence of recycled plastics in vehicles; this potential exposure source may be increasing as vehicle producers aim to improve material circularity.

• Keywords
• Cars, Dust exposure, Flame retardants, PFAS, Time trends,
• MeSH
• Automobiles * statistics & numerical data   MeSH
• Halogenated Diphenyl Ethers analysis   MeSH
• Air Pollutants * analysis   MeSH
• Environmental Monitoring * MeSH
• Organophosphates * analysis   MeSH
• Dust * analysis   MeSH
• Flame Retardants * analysis   MeSH
• Air Pollution, Indoor * analysis   statistics & numerical data   MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Halogenated Diphenyl Ethers MeSH
• Air Pollutants * MeSH
• Organophosphates * MeSH
• Dust * MeSH
• Flame Retardants * MeSH

Passive samplers based on diffusive gradients in thin hydrogel films (DGT) were recently modified for sampling of polar organic compounds in water. However, since the sampling rates of the commonly used DGT design with the surface area of 3.1 cm2 are low, we propose to increase them by applying a two-sided design with a larger sampling surface area of 22.7 cm2. The sampler design consists of two sorptive hydrogel disks compressed between two diffusive hydrogel disk layers strengthened by nylon netting and held together by two stainless steel rings. Sorbent/water distribution coefficients (KSW) were determined, and the sampler was calibrated for monitoring 11 perfluoroalkyl substances and 12 pharmaceuticals and personal care products in water at laboratory conditions using a closed system with artificial flow generated by submersible pumps. A field performance test was conducted at five locations in the Morava River basin in Czech Republic. The median value of laboratory-derived sampling rates was 43 mL day-1 with extreme values of 2 mL day-1 and 90 mL day-1 for perfluorotridecanoic and perfluoroheptanoic acids, respectively. The log KSW values of tested compounds ranged from 3.18 to 5.47 L kg-1, and the estimated halftime to attain sampler-water equilibrium ranged from 2 days to more than 28 days, which is the maximum recommended exposure period, considering potential issues with the stability of hydrogel. The sampler can be used for assessment of spatial trends as well as estimation of aqueous concentration of investigated polar compounds.

• Keywords
• Diffusive gradients in thin films (DGT), Hydrogel, Passive sampling, Polar organic compounds, Water monitoring,
• MeSH
• Water Pollutants, Chemical analysis   MeSH
• Diffusion MeSH
• Fluorocarbons chemistry   MeSH
• Hydrogels chemistry   MeSH
• Heptanoic Acids chemistry   MeSH
• Organic Chemicals chemistry   MeSH
• Rivers chemistry   MeSH
• Sepharose chemistry   MeSH
• Water MeSH
• Publication type
• Journal Article MeSH
• Geographicals
• Czech Republic MeSH
• Names of Substances
• Water Pollutants, Chemical MeSH
• Fluorocarbons MeSH
• Hydrogels MeSH
• Heptanoic Acids MeSH
• Organic Chemicals MeSH
• perfluoro-n-heptanoic acid MeSH Browser
• Sepharose MeSH
• Water MeSH