Table 1 Summary of priority research initiatives to advance microplastic research
Category | Recommendation | Priority Research Initiatives |
|---|---|---|
Particle Characterization | Identify microplastic characteristics that best predict hazards through extensive particle characterization and toxicity screening | • Comparative studies to determine the relative toxicities of different types of microplastics • Detailed particle characterization beyond size, polymer, and morphology (e.g., volume, surface area, associated chemicals, charge, functionalization, particle behavior, biomolecular corona) to allow potential correlations between particle metrics and observed effects |
Better characterize microplastic hazards by conducting toxicity tests using polydisperse, environmentally relevant distributions of microplastic particles | • Toxicity studies using well characterized, environmentally relevant mixtures of particles (e.g., diverse morphologies, polymers, sizes, etc.) • Toxicity studies using understudied but environmentally prevalent and well characterized microplastic types (e.g., fibers, tire wear particles, paint, recycled plastics) • Toxicity studies using weathered particles obtained using well-described methods | |
Threshold Development | Design experiments to generate robust dose/concentration-response data for health-based threshold development | • In vivo and in vitro toxicity studies with a sufficient number (3 minimum) and range of concentrations (including environmentally detected) to determine dose/concentration-response relationships |
Toxicological Pathways | Connect microplastics to existing or novel adverse outcome pathways | • More fully describe key events across levels of biological organization leading to negative impacts following microplastic exposure |
Increase the relevance of in vitro studies for hazard characterization by developing a framework for extrapolating in vitro results to in vivo effects | • Development of quantitative in vitro to in vivo extrapolation (QIVIVE) approaches to connect in vitro concentration-effect relationships to in vivo dose-response relationships • Development of physiologically based kinetic (PBK) models to predict particle kinetics in vivo | |
Exposure Characterization | Characterize understudied microplastic exposure routes | • Describe microplastic exposure and toxicity in sediment-dwelling aquatic organisms • Comprehensive microplastic exposure assessment for human health |