Report from a seminar jointly organized by the Norwegian Environment Agency and the Norwegian Institute of Public Health
Micro- and Nanoplastics from a Human Health Perspective
Report
|Published
|This report summarizes a national seminar organized by the Norwegian Environment Agency and the Norwegian Institute of Public Health on plastics and human health, bringing together invited researchers and health and environmental authorities working on plastic-related issues related to human health.
Key message
Key findings and knowledge gaps identified during the seminar are:
- Micro- and nanoplastic particles are widespread in the Norwegian environment, and humans are continuously exposed through air, food, water and everyday products.
- Major knowledge gaps remain regarding exposure levels, health effects, and how to measure micro- and nanoplastic particles reliably. This limits current risk assessment and the ability to set safe levels.
- There is increasing evidence from laboratory studies that micro- and nanoplastics can affect cells, but it is still unclear whether current exposure levels cause harm to human health.
- Plastics contain a very large number of chemicals, many of which are insufficiently studied. People are exposed to complex mixtures of these chemicals, and some have been linked to health effects, particularly during early life stages.
- There is an urgent need for coordinated, long-term research and collaboration across research areas on possible health effects, improved monitoring of exposure in the population, and better harmonized analytical methods and protocols to strengthen the scientific basis for risk assessment and regulation.
- Reducing exposure to plastic particles and hazardous chemicals, improving transparency about chemicals in plastics, and developing safer and more sustainable materials are important steps to protect human health in the future.
Summary
The seminar “Micro- and Nanoplastics from a Human Health Perspective” was aimed at summarizing the existing knowledge on micro- and nanoplastics (MNP) exposure, plastic-related chemicals, health impacts and analytical challenges for relevant authorities and to identify knowledge gaps and research needs. The workshop was jointly organized by the Norwegian Environment Agency (NEA) and the Norwegian Institute of Public Health (NIPH).
The seminar, which brought together presentations on the current state of research from Norwegian and international research institutions, panel discussions with governmental bodies, and active audience engagement, provided a shared overview of existing knowledge and highlighted key considerations for how Norway can strengthen research and regulatory efforts to better protect human populations from potential adverse health effects of MNPs and plastic-associated chemicals.
MNP exposure
Human exposure to MNPs can occur through multiple sources. MNPs are found in air, water, soil, fauna and flora throughout Norway, as presented in this seminar. Speakers identified agriculture as a key source of MNPs in food systems, while car tires contribute most to MNPs in urban environments. Biologically, it is plausible that the smallest particles (smaller than 1 to 2 µm), often referred to as nanoplastics, can cross biological barriers in the human body. Based on numerous recent reports, there is consensus in the scientific community that nanoplastics are present in the human body, while there are uncertainties on the amounts and their fate within our bodies.
Analyses of MNPs in human samples
Measuring MNPs of a size range smaller than 1 µm in human tissues is challenging due to limitations of available analytical instrumentation and contamination of samples during collection and processing. In addition, interferences caused by organic residues after incomplete sample preparation can give an overestimation of the amount of plastics in biological tissues. On the other hand, loss of MNPs during sample preparation is difficult to monitor, due to the lack of suitable reference samples, potentially causing underestimation. To address these challenges, strict protocols need to be applied to ensure robust and sensitive data reporting. A combination of high-end analytical methods for the detection of MNPs in biological tissues, and particularly human samples, is needed according to international expert groups. Progress in developing new sensitive methods, harmonized analytical protocols and standardization applicable in human samples is an ongoing process with international efforts.
Human health impacts of MNPs
Evidence is emerging that MNPs cause cellular effects such as oxidative stress, inflammation, impacts on membrane integrity and intercellular communication when tested in vitro. In most of these studies, relatively high doses of MNPs were used. An increasing number of scientific papers lists adverse health outcomes that may be associated with MNP exposures, but causal relationships are far from being demonstrated. At this point in time, we do not have enough data linking exposure of MNPs to potential health effects in humans. The presence of plastics in the human body is not automatically a hazard to human health.
Hazard assessment of MNPs
Currently we are still in the phase of hazard identification. Studies to benchmark the hazards of MNPs towards the hazards of other already better-studied particles should assist in the hazard assessment (e.g. inorganic nanoparticles, asbestos). To advance hazard assessment of MNPs, nanoplastics with varied polymers, shapes, composition, and surface chemistry are essential for toxicological testing and biomonitoring. A thorough characterization of the MNPs intended for toxicological testing is needed while effective cellular exposure must be demonstrated. Given continuous human exposure to MNPs, more knowledge of the health effects associated with chronic exposure is needed to support hazard and risk assessment. This requires well-designed and well-conducted experimental and epidemiological studies.
Chemicals in plastics
Based on the PlastChem report and its updated version, more than 16,000 chemicals may be present in plastics, including additives, monomers, and non-intentionally added substances. Hazard data is lacking for these chemicals, and information on human exposure is limited. Humans are continuously exposed to complex mixtures of plastic-associated chemicals through food, drinking water, air and dust, building materials, and everyday consumer products. While some migration and biomonitoring data exist, large knowledge gaps remain for most substances.
Human biomonitoring studies in Norway, including the Environmental Biobank (a sub-study of the Norwegian Mother, Father and Child Cohort Study, MoBa), show widespread human exposure to plastic chemicals such as phthalates, bisphenols, PFAS, and flame retardants in children and adolescents. Importantly, many chemicals lack defined safety thresholds and hazard data, and current assessments do not adequately address mixture effects. If these samples can also be used for the biomonitoring of MNPs is highly uncertain due to the lack of appropriate protocols in place during sampling collection.
Epidemiological findings from the MoBa-based NeuroTox-study indicate that prenatal exposure to plastic-related chemicals is associated with adverse neurodevelopmental outcomes such as ADHD, autism, and lowered cognitive function in children. More broadly, these chemicals have been linked to reproductive, metabolic, and cardiovascular disorders, as well as certain cancers, with fetal development appearing particularly sensitive. For most of these health effect associations, we lack a mechanistic understanding.
Large knowledge gaps persist regarding the persistence, bioaccumulation, mobility, and toxicity of many substances associated with plastics. Ongoing research initiatives, such as the PARC PlasticLeach project, aim to address some of these gaps by identifying and characterizing hazardous chemicals that leach from plastic products and by generating data to support regulatory action. In parallel, continued development of resources such as the PlastChem database is improving transparency on chemical use, occurrence, and possible hazards, thereby supporting prioritization in both research and policy development.
Key priorities and outlook
Overall, there is a clear and urgent need for holistic research on MNPs and plastic-associated chemicals and human health, including toxicological testing, improved biomonitoring, improved exposure characterization, and assessment of mixture effects. In addition, sound regulatory action to limit MNP exposure, phasing out chemicals of concern, increasing transparency on chemical composition of plastics, the development of safer and more sustainable plastic materials is needed to reduce potential risks to human health.
During the seminar, it was recognized that possible health effects of plastics are complex cross-sectorial topics, and interlinked collaboration across universities, research institutes, authorities, municipalities and industry is needed. Several ideas for the way ahead were discussed: 1) A follow-up seminar was suggested, including participation from municipalities, NGOs and industry for knowledge dissemination, exchange of insights, and identifying solutions to limit human exposure. 2) Establishing a national research center on plastics and human health combining many research fields by expanded biomonitoring, improved chemical characterization and well-designed experimental and epidemiological studies. Both MNP and chemicals in plastics are in scope of the proposed center.