A test materials strategy has been established covering relevant polymer particles (such as PE, PET, PP, PS) and made available for method testing and validation. We have continued to focus on organizing the supply of test materials and supporting material characterization for exposure, fate and hazard assessment. Tasks included the selection and characterization of additional MNPs (in particular of sub-micro- and nanosized as well as fiber materials), evaluation of analytical techniques, physicochemical material characterization for exposure and hazard testing, and method validation. Collaborative efforts led to the development of protocols for sample preparation and purification, and analytical techniques suitable for MNP identification, detection and measurement. Additionally, in vitro digestion models and leaching approaches were established to simulate MNP translocation and bio-transformation in the gut, and the leaching of additives from NP particles and how this may change the overall toxicity. Also, inter-laboratory comparison studies (ILS) have been implemented to ensure method accuracy and reliability for particle detection and size measurement.
We have also delivered significant achievements in the development and validation of computational models for understanding MNP fate and behaviour after ingestion and inhalation. Studies on bottled water, food (still ongoing), indoor/outdoor air and personal care products provided valuable insights into real human exposure levels. Investigations into MNP effects on the human gut microbiome and chronic ingestion studies have been started. Close collaboration across the project facilitated the validation of human tissue digestion and exposure monitoring and biomonitoring protocols. Furthermore, a quality assurance/quality control document was drafted to ensure a high data quality and methodological consistency in MNP research.
Substantial progress was made in toxicity testing of MNPs, focusing on cell viability, cellular uptake, barrier integrity, and immunotoxic effects. Studies encompassed a wide range of in vitro models simulating acute and sub-acute exposure scenarios, human tissues and organs. Investigations into particle transport across biological barriers and bioaccumulation studies provided valuable insights. Collaborative efforts are ongoing to establish inter-laboratory comparisons of in vitro and in vivo studies also by engaging in CUSP meetings to facilitate knowledge exchange.
Work progress has also been made to enhance human health risk assessment for MNPs and associated chemicals through an Integrated Approach to Testing and Assessment (IATA). We are developing decision support systems and prospective risk assessment tools to guide regulatory decision-making. Ambitious publications are planned to address risk assessment approaches and regulatory gaps, with a focus on supporting relevant EU policies and regulations.
We are also testing critical methodologies and strategies developed in the project through a number of case studies. Activities included method validation for occupational exposure monitoring and human biomonitoring, investigation of MNP surfaces to serve as potential vectors for pathogens and contaminants, and preliminary studies on long-term effects of MNPs through uptake in the lung and the food-web. Regular coordination meetings are organised across WPs to ensure feedback and method improvement and standardization.
All project findings achieved so far have been actively disseminated, to engage stakeholders, and shape policy discourse, also within CUSP. Efforts included the development of dissemination plans, web portals, training workshops, and policy recommendations. Collaborative engagement across sectors significantly enhanced PlasticsFatE's visibility and influence, contributing to broader efforts addressing MNP-related challenges.
