We can't find the internet
Attempting to reconnect
Something went wrong!
Hang in there while we get back on track
Evaluating microplastic particles as vectors of exposure for plastic additive chemicals using a food web model
AI summary Read the abstract
Researchers used a bioaccumulation model to estimate how much chemical exposure humans and wildlife receive specifically from ingesting microplastic particles — versus other environmental routes — and found that microplastics only become a meaningful source of chemical additives when ingestion rates are high and the plastic contains substantial concentrations of hydrophobic chemicals. The work helps clarify when microplastics are a significant chemical vector, finding that health risks from this pathway are likely negligible at currently estimated ingestion rates.
Microplastic particles (MPs) represent potential hazards for humans and wildlife, including as vectors for chemical exposure (e.g. plastic additives and pollutants sorbed from the surrounding environment). The leaching of chemicals from MPs has been identified as a potential exposure pathway but the relative magnitude of this pathway under environmentally relevant conditions remains unclear. Here, we describe a modification of the ACC-HUMANSTEADY bioaccumulation model to include dietary exposure to MPs containing either accumulated chemicals from the surrounding environment or embedded plastic additive chemicals (PACs). Chemical transfer to humans and wildlife is described using two-film resistance concepts assuming spheroidal particles of different sizes. The relative contribution of MPs and environmental media to the estimated daily chemical intake in humans was assessed in various exposure scenarios, for a range of hypothetical chemicals with varying octanol-water and air-water partition coefficients (KOW and KAW, respectively; i.e. 0 < log KOW <8 and − 5 < log KAW < 3). Results imply that MPs could act as sources of exposure to chemical additives when the ingestion rate of 1 μm MPs is ≥ 10 mg d− 1, and the concentration of hydrophobic plastic additive is ≥ 5% wt wt− 1. The contribution made by MPs as vectors of exposure decreased with increasing particle size and decreasing ingestion rates of MPs. Human health risks were evaluated for four specific PACs to illustrate the application of the model for risk assessment. Risks were negligible when the ingestion rate of MPs was < 100 μg d− 1. Uncertainties are high regarding the characterization and quantification of ingestion of MPs by humans and wildlife, including particle sizes and polymer composition, as well as on the presence of PACs in MPs. These data gaps need to be addressed if the issue of MPs as vectors of chemical exposure is to be fully understood. The work illustrates that mechanistic models, which account for all major exposure pathways, can be used to identify the importance of different exposure pathways, help prioritize research needs and support decision making.
More Papers Like This
Evaluating nano- and microplastic particles as vectors of exposure for plastic additive chemicals using a food web model: Implications for risk to human health
AI summary Read the abstract
This review evaluated nano- and microplastic particles as vectors for chemical exposure, examining how plastic additives and sorbed environmental contaminants leach from particles under environmentally relevant conditions. The analysis found that while leaching occurs, risks to human health at realistic environmental concentrations require further quantification.
Microplastic as a Vector for Chemicals in the Aquatic Environment: Critical Review and Model-Supported Reinterpretation of Empirical Studies
AI summary Read the abstract
Researchers critically reviewed the widespread hypothesis that microplastics transfer harmful chemicals to marine animals after being ingested. Using new modeling calculations, they found that for most organisms in most scenarios, the contribution of microplastics to chemical exposure is actually very small compared to what animals absorb through water and food. The study suggests that while microplastics are a legitimate environmental concern, their role as a significant chemical delivery vehicle has been overstated in much of the scientific literature.
Weight of Evidence for the Microplastic Vector Effect in the Context of Chemical Risk Assessment
AI summary Read the abstract
This study critically evaluates the evidence for microplastics acting as vectors that increase organism exposure to plastic-associated chemicals, finding that the vector effect is generally minor compared to other exposure routes in realistic environmental scenarios.
Bioaccessibility of plastic-related compounds from polymeric particles in marine settings: Are microplastics the principal vector of phthalate ester congeners and bisphenol A towards marine vertebrates?
AI summary Read the abstract
Researchers studied whether microplastics are a major pathway for delivering harmful plastic chemicals like phthalates and bisphenol A to marine animals during digestion. They found that while microplastics do release these compounds under simulated gut conditions, the amounts were relatively low compared to other environmental sources. The study suggests that microplastics may not be the primary route of chemical exposure for marine vertebrates, though they still contribute to the overall burden.
Modeling the Role of Microplastics in Bioaccumulation of Organic Chemicals to Marine Aquatic Organisms. A Critical Review
AI summary Read the abstract
Researchers reviewed mathematical models used to predict whether swallowing microplastics causes aquatic animals to absorb more toxic chemicals, finding that the effect depends on whether contaminants are more concentrated in the plastic or in the animal's tissues. In real-world conditions where animals are already exposed to contaminants, microplastics may actually pull chemicals out of tissues as often as they add them, complicating the assumption that microplastic ingestion always increases contamination.
Research digests by email
When a large batch of papers lands in the Atlas, we read through it and send a short write-up of what stood out.