[co-author: Ellen Hartley, MLISc]
In light of the increasing reports highlighting the presence of micro- and nanoplastics (MNPs) in our food and beverages, it is essential for the scientific community and media to approach these findings with a balanced perspective.
Recent Findings and Public Concerns
Recent studies have detected higher levels of MNPs in bottled water than previous estimates, with some research indicating up to 240,000 particles per liter. This notable increase in observed concentrations has raised public concern about potential human health impacts and led to litigation. However, the mere presence of MNPs does not necessarily equate to a health risk. The key question remains: At what exposure levels do these particles begin to pose a real threat to human health? The answer to this is complex and requires a comprehensive evaluation of the nature of the MNPs, relevant toxicological data, and food- and beverage-specific exposure assessments.
Advances in Detection and Research
The surge in reported findings of MNPs in foods and beverages can be attributed to two factors:
- Increased research interest in MNPs
- Advancements in analytical techniques with increased sensitivity.
While we can now detect and quantify contaminants that were previously invisible, a scientific understanding of the potential health risks associated with MNPs requires further consideration.
Variability and Complexity of MNPs
MNPs are highly variable, differing in size, shape, and composition. They can originate from various synthetic polymers and may contain functional additives such as plasticizers or flame retardants and pigments or dyes. MNPs have also been reported to adsorb and carry unrelated chemicals on their surfaces, thus serving as vectors for other environmental pollutants and potentially increasing the toxicity of the MNPs as they enter the human food chain. The extent and conditions under which this occurs are still under investigation, emphasizing the importance of considering the chemical makeup and behavior of these particles in various environmental contexts, rather than making broad generalizations based on MNP presence alone.
Hazard and Dose-Response Assessments
The toxicological characterization of MNPs is only slowly emerging because it was long assumed that the bioavailability of these insoluble high-molecular weight polymers is negligible. However, hazards associated with MNP ingestion and effect thresholds must be studied to derive safe human exposure levels. Different materials and co-contaminants might exert toxicity in different target tissues and at different doses. No-observed-adverse-effect levels can differ depending on size and shape of MNPs, even if their composition is unchanged. Only a comprehensive integration of safety data that is specific to the MNPs of interest can yield insights for assessing human safety. Aggregate exposure from multiple sources and combined exposure to different MNPs further complicate risk assessment of MNPs from food and beverages.
The environmental persistence and biodegradation of MNPs are critical factors that need further elucidation. Some plastics may degrade into harmless breakdown products, while others persist in the environment, posing long-term ecological risks and increasing the chances of MNPs entering the human food chain. The rate and extent of these processes vary widely depending on the type of plastic, environmental conditions, and presence of biofilms. Understanding these dynamics is crucial for assessing the true impact of MNPs on ecosystems and human health.
Towards a Balanced Understanding
The detection of MNPs in food and beverages warrants attention, but scientists and the media must maintain a critical eye. The presence of these particles does not inherently signify a health crisis. Instead, it should prompt a careful examination of their sources, pathways of exposure, and interactions with other environmental factors. By adopting a measured and evidence-based approach, we can better discern the real risks and develop effective strategies to mitigate potential impacts on human health.
Supporting Scientific Studies and Research
Alqahtani, S., S. Alqahtani, Q. Saquib, and F. Mohiddin. 2023. Toxicological impact of microplastics and nanoplastics on humans: Understanding the mechanistic aspect of the interaction. Front. Toxicol. 5:1193386. Available online at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10375051/
Amobonye, A., P. Bhagwat, S. Raveendran, S. Singh, and S. Pillai. 2021. Environmental impacts of microplastics and nanoplastics: A current overview. Front. Microbiol. 12:768297. Available online at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8714882/
Balch, B. 2024. Microplastics are inside us all. What does that mean for our health? AAMC. Available online at: https://www.aamc.org/news/microplastics-are-inside-us-all-what-does-mean-our-health
Contie, V. 2024. Plastic particles in bottled water. NIH Research Matters. Available online at: https://www.nih.gov/news-events/nih-research-matters/plastic-particles-bottled-water. National Institutes of Health, Bethesda, Maryland.
Fang, C., Y. Luo, and R. Naidu. 2023. Microplastics and nanoplastics analysis: Options, imaging, advancements and challenges. TrAC Trends in Analytical Chemistry 166:117158. Available online at: https://www.sciencedirect.com/science/article/pii/S0165993623002455
Food Safety Magazine Editorial Team. 2024. New microscopic detection technique reveals more plastic in bottled water than previously known. Food Safety Magazine. Available online at: https://www.food-safety.com/articles/9152-new-microscopic-detection-technique-reveals-more-plastic-in-bottled-water-than-previously-known.
Kwon, J.-H., J.-W. Kim, T.D. Pham, A. Tarafdar, S. Hong, S.-H. Chun, S.-H. Lee, et al. 2020. Microplastics in food: A review on analytical methods and challenges. Int. J. Environ. Res. Public Health. 17(18):6710. Available online at: https://ideas.repec.org/a/gam/jijerp/v17y2020i18p6710-d413759.html
Sutkar, P.R., R.D. Gadewar, and V.P. Dhulap. 2023. Recent trends in degradation of microplastics in the environment: A state-of-the-art review. Journal of Hazardous Materials Advances 11:100343. Available online at: https://www.sciencedirect.com/science/article/pii/S2772416623001146
