Paradigms to assess the human health risks of nano- and microplastics

Abstract

Human exposure to nano- and microplastics (NMPs) has raised major societal concerns, yet no framework to assess the risks of NMPs for human health exists. A substantial proportion of plastic produced worldwide is not properly disposed and persists in the environment for decades while degrading. Plastic degradation generates a size continuum of fragments, including nano- and microplastic particles, with numerous associated environmental pollutants and plastic additives, and microbial communities colonising their surfaces. The ubiquitous presence of NMPs, their availability for uptake by organisms and their potential to act as vectors for toxicants and pathogens render risk assessment a priority on the political agenda at the global level. We provide a new, fully integrated risk assessment framework tailored to the specificities of NMPs, enabling an assessment of current and future human health risks from NMPs. The framework consists of four novel paradigms to the traditional risk assessment methodology. These paradigms deal with techniques in NMP analysis, gaps in empirical data, theoretical and modelling approaches and stakeholder engagement. Within the proposed framework, we propose how we can use research experiences gained so far to carry out the different steps of the assessment process, and we define priorities for further research.

Development and application of a health-based framework for informing regulatory action in relation to exposure of microplastic particles in California drinking water

“…A detailed discussion of the Tier 1 evaluation process used to inform this study is presented in Gouin et al, [ 42 ]. Noting that the availability of quantitative in vitro to in vivo extrapolation (“QIVIVE”) models are currently not available, and which represents an important research need (Romeo et al, [ 97 ]; Noventa et al, [ 77 ]; Gouin et al, [ 42 ]), the discussion presented here is thus largely limited to the results reporting dose–response relationships from mammalian in vivo studies. Specifically, the derivation of a screening level for use in estimating a health-based threshold for informing regulatory and monitoring activities is based entirely on results obtained from in vivo studies.…”

“…While methods exist for quantitatively extrapolating from in vitro to in vivo systems for soluble contaminants (e.g., predicting estrogenic potencies of bisphenol A—Punt et al, [ 89 ]), methods are currently under development for insoluble (i.e. particulate) contaminants (Romeo et al, [ 97 ]), and while useful as screening tools for potential effects, in vitro studies cannot (yet) be unconditionally used for human health risk assessment (Noventa et al, [ 77 ]). Accordingly, only in vivo studies were screened and prioritized for further assessment.…”

A Children’s Health Perspective on Nano- and Microplastics

“…For instance, ongoing mother-child cohort studies should include aspects of exposure to NMPs, such as sampling in child-relevant materials and questionnaire data on plastics use and contact. Growing the knowledge base about child health and plastics requires the development of a joint terminology and consensus on appropriate quality standards, as well as the establishment of technical, scientific, and science-policy forums to exchange data, knowledge, and ideas; some of this work has already started (Noventa et al 2021;Zarus et al 2021). Importantly, outputs should be co-created and communicated with stakeholders, such as families and children themselves.…”

The Biological Effects of Polystyrene Nanoplastics on Human Peripheral Blood Lymphocytes

“…The source and origin of both MPs and NPs are ubiquitous in the environment, as most MPs are the product of continuous degradation and fragmentation of large plastics, in addition to the intentional addition of micron-sized plastic or fiber particles in many consumer products, such as facial scrubs, paints, textiles, etc. On the other hand, NPs are derived from the further degradation of MPs [ 7 ]. Due to their ever-presence in different environments, making humans vulnerable to frequent exposure via several known and unknown pathways, it is imperative to assess their possible harmful effects on human health [ 7 ].…”

“…On the other hand, NPs are derived from the further degradation of MPs [ 7 ]. Due to their ever-presence in different environments, making humans vulnerable to frequent exposure via several known and unknown pathways, it is imperative to assess their possible harmful effects on human health [ 7 ].…”