Microplastics

While research on microplastics has expanded in recent years, substantial gaps remain in understanding their characteristics, sources, environmental fate, and potential health effects. These include how to detect and quantify them, trace their movement through environmental media, and assess actual exposure levels and potential risks. The global plastics and chemical industries are contributing to the scientific knowledge base by supporting credible research and advocating for policies grounded in evidence and feasibility.¹ The Plastics Industry Association (PLASTICS) aligns with the WHO’s position that further research is needed ²and is leading initiatives to reduce plastic waste and prevent its entry into the environment.

What are Microplastics?

Definitions of microplastics vary but typically focus on particle size, often without sufficient consideration of composition or analytical feasibility. PLASTICS supports refining these definitions to align with evolving detection technologies and meaningful distinctions in composition and behavior. The most commonly cited size range for microplastics is 5 millimeters (mm) down to 1 nanometer (nm).³ The International Organization for Standardization (ISO) further classifies “large microplastics” as 1-5 mm and “microplastics” as 1 micrometer (um) to 1 mm.⁴ Consistent and technically grounded definitions are critical to ensure that policy decisions reflect science capability and material science.

Microplastics are generally described as belonging to one of two broad categories: primary and secondary microplastics. Primary microplastics are intentionally manufactured small particles, such as microbeads in personal care products or controlled-release fertilizers. Secondary microplastics, by contrast, result from the breakdown of larger plastic items through physical, chemical, and biological processes. These fragments can originate from a range of sources, including paint, tire wear, textiles, and geotextiles. ⁵

Environmental and Human Health

Studies have reported the detection of microplastics in various environmental media, food sources, and human tissues. However, detection alone does not equate to demonstrated harm. The current scientific evidence is limited by a lack of standardized, validated methods for detecting, identifying, and quantifying microplastics across complex sample types, including complex foods⁶, air samples⁷, tissues⁸, and others. These analytical challenges contribute to significant uncertainty about exposure levels, toxicological relevance, and potential health effects.

Leading scientific and regulatory agencies have reviewed the current evidence and generally conclude that the available data are insufficient to establish health risks from typical levels of microplastic exposure. These organizations consistently emphasize the need for more research, better methods, and improved data transparency.

The World Health Organization (2022)⁹: “Strengthening of the evidence necessary for reliable characterization and quantification of the risks to human health posed by NMP [nano- and micro-plastics] will require active participation by all stakeholders in developing and making available standard methods”

The US FDA (2024)¹⁰ : “While some studies suggest there may be impacts to human health from exposure to microplastics and nanoplastics, the overall scientific evidence does not demonstrate that levels of microplastics or nanoplastics found in foods pose a risk to human health”

The German Federal Institute for Risk Assessment (BfR, 2025)¹¹: “According to the current state of knowledge, there is no reliable toxicological evidence of health risks from the ingestion of microplastics via food.”