Exposure and hazard data are instrumental to assess (human) health risks. The current state of the art is limited with regard to key technologies to assess exposure levels and hazards of MNP. POLYRISK will develop and provide standard operating procedures (SOPs) to perform physico-chemical analyses of microplastics (above 100 nm) in airborne, blood and water samples. In particular for innovative analyses in complex matrices (e.g. blood) will have potential impact with regard to execution of future studies into health effects of MNP. A particular expertise of POLYRISK is the possibility to analyse MNP of nanosize (<50 nm, using). The technology applied (AFM-PIFM) will enable answering specific questions, but will not likely be implementable as quantitative technology.
The test strategy foreseen for hazard assessment for MNP will be a tiered one, and includes fit-for-purpose in vitro test methods, as much as possible using human cells. Such a strategy was already proposed for toxicity testing of nanoparticles, but needs adaption for the case of MNP. A similar challenge is dosimetry of particles in cellular in vitro methods. Special for MNP is the complex chemistry, which combines MNP specific chemicals and leachates with adsorbed environmental (chemical and microbial pollutants). POLYRISK aims to offer innovative exposure technologies and provide new information on effects of weathering and aging of MNP. POLYRISK will focus on immunotoxicological effects MNP, in particular those that are inflammation-related. Selection of methods used is guided by the recently defined key events of inflammation. These methods will be used to test virgin as well as laboratory aged MNP and particles collected during the scenario studies. Together with exposure and health effect findings obtained in our unique and human-relevant scenario studies, POLYRISK will potentially provide unique data allowing direct in vitro to in vivo translation of MNP’s effects.
Selection of in vitro test methods of POLYRISK are centered around key event (KE) of inflammation, that have been recently defined as hubs of many inflammatory adverse outcomes (Villeneuve et al 2018). These KE include cellular activation, release of inflammatory mediators and recruitment of leukocytes. We will use methods to assess KE-related effects but also methods to assess in vitro exposure, in particular uptake of MNP by epithelial cells and leukocytes. With these methods we have already provided new insights (van den Berg et al) and expect to deliver additional mechanistic insights. This knowledge will be of strategic importance in safety-by-design R&D of new MNP.
Need for science based input for policy making and regulation.
POLYRISK is providing a state of the art risk assessment framework, that is adjusted to logically combine existing regulatory guidances for fibres, polymer of low concern, and particles. POLYRISK will thus potentially contribute to an innovative Integrated Approach to Testing and Assessment (IATA) and a novel human risk assessment framework for MNP. Such a IARA and HRA will impact on policy making and regulation.
Society is increasingly concerned about the overwhelming plastic worldwide environmental pollution. Knowledge on potential health effects of MNP on human health is barely available and highly needed. With its unique project approach, combining high-end physico-chemical analytical technologies, with tiered in vitro approaches to test MNP’s immunotoxicity and human exposure and effect studies, POLYRISK will be able provide required information to better substantiate existing concerns.
