Rivers and streams are important conduits for microplastic particles from terrestrial sources to marine environments. Submerged macrophytes are expected to influence microplastic short-term retention by altering local hydrodynamics and trapping microplastics. However, their impact in longitudinal transport processes remains unclear. We investigated the fate of three particle types - polystyrene (PS), polyethylene terephthalate (PET), and tire wear particles (TWP) - within replicated 45 m stream mesocosms which varied in vegetation densities of the macrophyte Elodea nuttallii (comprising either 0%, 25%, or 100% density, n = 3). Following a controlled pulse release, microplastic concentrations were quantified in the water column, sediment, and macrophyte biomass. Retention within macrophytes was strongly particle-specific ( p = 0.007): TWP accumulated at the highest levels, with spatial variability being reduced under high vegetation density (T 100 ), whereas PET and PS consistently exhibited low accumulation across treatments. Apparent distance-decay rates revealed consistent particle-specific transport behaviors across water and sediment compartments. Streambed accumulation was significantly affected by particle type and distance ( p < 0.001), whereas vegetation density showed no significant overall effect ( p = 0.903). However, significant vegetation × distance and vegetation × particle interactions indicated that vegetation effects depended on stream position and particle identity. In both sediment and water samples, PS concentrations declined markedly with increasing distance, PET showed a moderate decrease and persisted downstream, while TWP remained constant across distance and compartments. These results indicate that particle-specific properties and transport distance dominate microplastic dynamics in streams, while vegetation modulates local retention depending on stream position and particle type. This highlights the function of small, vegetated streams with limited filtration capacity as temporary particle-specific sinks for microplastics. They may act as secondary sources of microplastics within fluvial networks, thereby affecting the timing and magnitude of downstream microplastic transport. Considering the substantial contribution of small streams to river networks in terms of total flow length, their capacity to temporarily retain and subsequently remobilize microplastics may have important implications for catchment-scale plastic budgets and in a wider context the transfer from terrestrial to marine environments.
Textile-derived fibers and particles are increasingly recognized as an important source of human and environmental exposure. While synthetic textile particles have been intensively studied as a major source of micro- and nanoplastic (MNP) pollution, textile emissions in real-world environments are far more diverse and include synthetic, natural and biobased materials. Regardless of their origin, these materials release highly complex particulate mixtures that vary widely in size, shape and chemical composition, and exhibit diverse fibrous and non-fibrous morphologies. Despite growing concern regarding the potential health impacts of released particles, current in vitro studies often lack environmental relevance as they rely on simplified, size-standardized, or pristine test materials that fail to mimic the complexity of real-world textile emissions. To address this challenge, we established a standardized, water-based Gyrowash extraction workflow to obtain sterile and environmentally relevant particle suspensions directly derived from textiles. The workflow preserved fiber integrity while providing sterile e.g. cell-culture-compatible samples that can be accurately quantified. The protocol was further optimized to enable a reproducible assessment of material-driven effects in the Calu-3 lung epithelial cell model. Optional steps for advanced physiochemical characterization are included to facilitate comprehensive material analysis and identification of potential contamination sources. Overall, this workflow provides a robust and standardized platform for obtaining representative textile-derived particle samples and supports more realistic and comparable investigations of their health effects.
Anthropogenic microparticles, including microplastics, have become a pervasive, global environmental issue in all biomes. In marine systems, their impacts on large pelagic predators remain poorly quantified, limiting our ability to understand exposure pathways and ecological consequences. Salmon sharks (Lamna ditropis), regionally endothermic predators in the North Pacific, may be vulnerable to microparticle ingestion due to their high energetic demands, broad diet, and exploitation of coastal and offshore habitats known to contain relatively high amounts of pollution. To assess exposure in this species, we analyzed stomachs from 18 salmon sharks collected off the Oregon coast between 2022 and 2024 and evaluated differences across ontogenetic and sex classes as well as microparticle counts in their prey. Anthropogenic microparticles were found in every shark stomach, with an average (± SD) of 25.6 ± 23.0 microparticles per stomach. Anthropogenic microparticles were dominated by fibers and fragments, with white and black being the most common colors. µFTIR spectroscopy confirmed approximately 16
Human health risk assessment for microplastics (MPs) rests on an implicit assumption: that ingestion exposure estimates can be translated into internal tissue dose and lifetime accumulation burden. This Critical Review evaluates whether the available human evidence base can support that translation, and argues that it cannot, not because of data scarcity alone, but for a structural reason: the underlying toxicokinetic (TK) systems are structurally non-identifiable under the measurement designs currently in use. Using a scoping review of 22 eligible studies to map empirical baseline data, we executed a synthetic dependency and sensitivity demonstration using a literature-anchored synthetic dataset and probabilistic Monte Carlo simulations to evaluate the structural integrity of commonly used intake–elimination assumptions. Quantitative analyses are restricted to microplastics of 1 μm or larger; nanoplastics (< 1 μm) are treated qualitatively throughout, because the analytical methods that detect them and the toxicokinetic evidence available for them differ substantially from those for microplastics. While this dependency simulation yields a seemingly robust and near-perfect relationship between estimated ingestion and faecal excretion (r = 0.949; no significance test is reported, as the variables are dependent by construction), we demonstrate that this correlation is a purely mathematical artifact of the model’s structural architecture rather than evidence of biological coupling. Individual clinical biomonitoring correlations (such as in tissue biopsies or fluids) are fundamentally uncoupled from ingestion paths due to unmeasured multi-route confounding. Synthesizing 22 studies across human biomonitoring, ex vivo organoid, animal, and in vitro mechanistic evidence, we show that no dataset co-measures intake and elimination in the same individuals and that tissue detections aggregate unattributed multi-route (ingestion, inhalation, dermal) burdens; fixed-fraction retention models are therefore fitted to structurally under-determined systems. We formalize this with a convolution model of multi-route tissue burden and demonstrate, via probabilistic simulation of a literature-anchored synthetic intake–excretion dataset, that the near-perfect intake–excretion correlations that arise when excretion is defined as a fixed fraction of intake (Pearson r ≈ 0.88–0.98 across Monte Carlo conditions) are a consequence of model construction, not evidence of biological coupling. We then derive the minimum identifiability conditions, longitudinal, same-subject, route-resolved intake–elimination–retention measurement that any valid human MP-TK model must satisfy and translate these into concrete study-design and reporting requirements. Reframing the field’s central problem from “insufficient data” to “structurally uninformative data” reorients microplastic risk assessment toward the specific measurements that would make quantitative body-burden modelling possible.
With 250–300 billion plastic-lined paper cups used worldwide each year, disposable coffee cups are a substantial yet underrecognized source of micro- and nanoplastics (MNPs) exposure. Whether MNPs released during routine use occur at biologically relevant levels remains unclear, as producing liner-derived particles in the quantities required for toxicity assays is difficult, and most studies instead use commercially manufactured spheres. In this study, we pair realistic particle generation with quantified consumer exposure to compare estimated intake against concentrations producing measurable biological responses. Femtosecond laser ablation of cup liner films produced irregular polyethylene (PE) MNPs spanning 1–2000 nm, over 80
