Microplastics

Airborne microplastics (MPs) are a global issue, and there is an urgent need to prevent their spread in the environment. Sensitive and reliable methods are also needed to assess their deposition and effectively evaluate risk in terrestrial ecosystems. Current automated monitoring devices are expensive and do not enable large-scale mapping of MP deposition. As with other persistent atmospheric contaminants, developing accurate, cost-effective and easily applicable biomonitoring methods would therefore be highly beneficial. Cryptogams are among the most suitable biomonitors of airborne contaminants, and preliminary surveys show that epiphytic lichens accumulate higher concentrations of MPs in urban areas and near landfills than in control sites. However, the interaction between lichen thalli and MPs is weak and, as discussed in this review, the anthropogenic fibres and plastic fragments intercepted and retained by lichens probably do not reflect the levels in bulk atmospheric deposition. While emphasizing the need for studies evaluating the effectiveness of cryptogams in accumulating different types of airborne MPs under various meteorological conditions, this review also suggests directing future research efforts toward mosses, which seem to accumulate much higher concentrations of MPs than lichens in both active and passive biomonitoring surveys.

Microplastics (MPs) are synthetic environmental pollutants increasingly linked to adverse human health effects. To study their biological impact, researchers require access to environmentally relevant MPs that can be accurately tracked in biological systems. However, most ambient MPs are composed of non-conjugated polymers that lack intrinsic fluorescence, limiting their utility in live-cell or in vivo imaging. Addressing this challenge, we present two alternative labeling approaches that enable visualization, tracking, and quantification of MPs. First, we stained nylon and polypropylene MPs with Rhodamine 6G, a fluorescent dye known for its stability and compatibility with in vivo applications. These labeled MPs retained strong fluorescence in murine lung tissue for up to one week, as confirmed by fluorescent microscopy. Second, we conjugated aminated polystyrene microspheres with IRDye-800CW, a near-infrared fluorophore that enables high-resolution imaging with minimal tissue autofluorescence via an In Vivo Imaging System and confocal microscopy. In vivo experiments revealed organ-specific accumulation of IRDye-labeled MPs, with a 2.8-fold increase in the liver and a 5-fold increase in spleen compared to controls, detectable up to 72 h post-injection. These labeling strategies provide researchers with practical tools to visualize and study the biodistribution of MPs in biological systems, advancing efforts to understand their health implications.

Plastic pollution is a major environmental concern. In humans, ingestion through contaminated seafood is a recognized exposure route to microplastics, which may impact gut health. However, the extent to which microplastics interfere with digestion and nutrient absorption remains unclear. To this end, the present work aimed to assess, for the first time, the influence of microplastic particles (polyethylene terephthalate, PET, and polylactic acid, PLA) on the digestibility of three selected seafood species (gilthead seabream, Sparus aurata; Atlantic salmon, Salmo salar; and hard clam, Mercenaria mercenaria) using an in vitro human digestion model. Furthermore, this study evaluated the potential degradability of microplastics along the gastrointestinal tract and examined how particle type and exposure level (10 or 20 particles) may influence seafood digestibility. Protein digestibility in S. aurata and S. salar filets was ~86%, while in M. mercenaria it was ~73%, regardless of microplastic presence or quantity. PET and PLA integrity was affected differently by digestion, with PLA showing greater surface degradation. These findings provide preliminary insight into the mutual interactions between microplastics and the human digestive process, highlighting the importance for further research into how the leaching of plastics additives may or may not influence the bioaccessibility of essential nutrients.