Microplastic fibres released in synthetic cloth washing have been shown to be a source of microplastics into the environment. The annual emission of polyester fibres from household washing machines has earlier been estimated to be 150,000 kg in a country with a population of 5.5 × 10⁶ (Finland). The objectives of this study were (1) to quantify the emissions of synthetic textile fibres discharged from five sequential machine washes (fibre number and length) and tumble dryings (fibre mass) and (2) to determine the collection efficiency of two commercial fibre traps. The synthetic fabrics were five types of polyester textiles, one polyamide and one polyacryl. The number of fibres released from the test fabrics in the first wash varied in the range from 1.0 × 10⁵ to 6.3 × 10⁶ kg⁻¹. The fibre lengths showed that the fleece fabrics released, on average, longer fibres than the technical sports t-shirts. The mass of fibres ranged from 10 to 1700 mg/kg w/w in the first drying. Fibre emissions showed a decreasing trend both in sequential washes and dryings. The ratio of the fibre emissions in machine wash to tumble drying varied between the fabrics: the ratio was larger than one to polyester and polyamide technical t-shirts whereas it was much lower to the other tested textiles. GuppyFriend washing bag and Cora Ball trapped 39% and 10% of the polyester fibres discharged in washings, respectively.

Only scarce information is available about the abundance of microplastics (MPs) in Nordic lakes. In this study, the occurrence, types, and distribution of MPs were assessed based on the lake water and sediment samples collected from a sub-basin of Lake Saimaa, Finland. The main goal was to estimate the possible effect of the local wastewater treatment plant (WWTP) on the abundance of MPs in different compartments of the recipient lake area. Collected bottom sediment samples were Cs-137 dated and the chronological structure was utilized to relate the concentrations of MPs to their sedimentation years. Raman microspectroscopy was used for the MPs' identification from both sample matrices. In addition, MPs consisting of polyethylene (PE), polypropylene (PP) and polystyrene (PS) were quantified from lake water samples by pyrolysis-gas chromatography-mass spectrometry to provide a complementary assessment of MPs based on two different analysis methods, which provide different metrics of the abundance of microplastics. MPs concentrations were highest in sediment samples closest to the discharge site of WWTP effluents (4400 ± 620 n/kg dw) compared to other sites. However, such a trend was not found in lake water samples (0.7 ± 0.1 n/L). Overall, microplastic fibers were relatively more abundant in sediment (70%) than in water (40%), and the majority of detected microplastic fibers were identified as polyester. This indicates that a part of textile fibers passing the WWTP processes accumulate in the sediment close to the discharge site. In addition, the abundance of MPs was revealed to have increased slightly during the last 30 years.

Microplastics, including tyre and road wear particles, have been detected in every environmental compartment in both urban and remote areas. However, their contribution to atmospheric particulate matter is still sparsely explored. These airborne micro- and nanosized particles are continuously inhaled and pose risks to the environment and public health. The objectives of this study were to develop and validate a thermoanalytical method for the quantification of microplastics in urban particulate matter. Aerosol particles smaller than 10 µm in aerodynamic diameter (PM₁₀) were sampled at the kerbside in Helsinki, Finland, during spring 2024. The samples were pretreated by homogenization and thermal desorption prior to chemical analysis by micro-furnace pyrolysis–gas chromatography–mass spectrometry. The developed method was validated in terms of selectivity, limits of quantification, linear range, trueness, precision, and measurement uncertainty. Instrument quantification levels were 8–270 ng. Expanded measurement uncertainties were 25–30% and 50–70% for the studied tyre wear rubbers and thermoplastics, respectively. Polyethylene, polyethylene terephthalate, polypropylene, polystyrene, and tyre and road wear particles were detected in urban PM₁₀ samples, and their sum accounts for 1–3% of total PM₁₀. These results represent the level of airborne microplastic particles to which people can be exposed in urban environments. Graphical Abstract

Biodegradable mulching films have been developed as an alternative to conventional agricultural plastics; however, concerns persist regarding the microplastics (MPs) generated during their degradation. This study investigates the mobility and fate of polybutylene adipate terephthalate (PBAT) fragments derived from biodegradable mulching films in surface runoff and infiltration under two scenarios: bare and cultivated soil. Six experimental units with soil amended with PBAT fragments (0.5 wt% in the upper 4 cm of soil) were used. Barley (Hordeum vulgare) was cultivated in three of the units. Irrigation and simulated rainfalls were applied, and natural rainfall was monitored. Runoff and infiltration water were collected over a 5-month period, and soil samples were analysed after harvesting. Results show that most biodegradable MPs remained in the topsoil. Cultivation enhanced MP retention, with 70% of particles found in the 0-5 cm layer and 29% in the 5-10 cm layer, compared with 50% and 7%, respectively, for bare soils. This suggests that vegetation reduces MP losses via runoff while promoting their movement towards deeper soil layers. Indeed, MP mobilization by runoff was very low in bare soils (1.6%), and cultivation further limited surface transport (0.02%). Less than 0.001% of MPs infiltrated through the unsaturated zone. The type of water-input event strongly influenced MP mobilization: high-intensity rainfall increased runoff-driven transport in bare soils, while the volume of infiltrating water conditions increased the penetration of MPs to deeper soil layers. Overall, this study provides critical insights into the behavior of biodegradable plastics in soil ecosystems.