Microplastics have become ubiquitous in natural and built environments, which has caused concern regarding potential harm to human and aquatic life. Microplastics – plastic particles ranging in size from five millimeters (mm) to one nanometer (nm) – have been found in every ecosystem on the planet from the Antarctic tundra to tropical coral reefs.1
Microplastics are microscopic pieces of plastic that break down from common plastic materials – such as food wrapping, tires, and synthetic fabrics – and end up in our environment. They vary in shape, size and morphology. The majority of these microplastics get washed away by rain, enter watersheds, and eventually end up in marine sediments. Sediments are under almost every water body and are primarily organic and mineral matter. They are important ecosystems and a major sink for contaminants but are often overlooked because they exist below the surface.2
According to one recent article from Remediation Technology “microplastics from tires can account for 30-40% of plastics pollution in the environment.” 4
Environmental Contamination
The plastics are often present in composites with nanomaterials such as carbon nanotubes or graphene oxide that maximize desirable properties like strength, conductivity, and antibacterial activity. Assuming current trends in production and no improvements in waste management, releases of microplastics into the environment may grow to 90 metric tons per year by 2030.5
Microplastics can occur as primary plastics that are introduced into the environment by industrial spills. However, most microplastic environmental contamination comes from the mechanical breakdown of plastic products such as pipes, plastic cups and bottles, carpet, and other plastic consumer and industrial products. These are known as secondary microplastics. Studies suggest that some bottled drinking water may even contain miniscule plastic particles introduced by the container and cap. 6
Health Concerns/Effects
Definitive evidence linking microplastic consumption to human health is currently lacking. However, results from correlative studies in people exposed to high concentrations of microplastics and model animal/cell culture experiments suggest that effects of microplastics could include provoking immune and stress responses and inducing reproductive and developmental toxicity. Further research is required to explore the potential implications of this recent contaminant in our environment in more rigorous clinical studies.7
The accumulation of microplastics worldwide has led to increasing amounts in not only marine life and nature, but also is now highly suspected in humans as well. A study was recently published that claimed microplastics were found within human blood.6
The health concern of microplastics for humans occurs from the ingestion of chemicals used in their manufacture or of pollutants that concentrate on the porous surface of the particles.6 Particles (<150 micrometers) can be ingested by living organisms, migrate through the intestinal wall and reach lymph nodes and other body organs. The primary pathway of human exposure to microplastics has been identified as gastrointestinal ingestion, pulmonary inhalation, and dermal infiltration.
Microplastics may pollute drinking water, bioaccumulate in the food chain, and release toxic chemicals that may cause disease, including certain cancers. They may pose acute toxicity, (sub) chronic toxicity, carcinogenicity, genotoxicity, and developmental toxicity. In addition, microplastics may pose chronic toxicity (cardiovascular toxicity, hepatotoxicity, and neurotoxicity). The toxicity of microplastics primarily depends on the particle size distribution and monomeric composition/characteristics of polymers.8
“Given the variety in plastics, there is no standard or ‘one size fits all’ method for quantifying microplastics in environmental samples. It makes it difficult to compare data and results of various studies when there are hundreds of methods used across the world.” What concerns us is that everywhere we look – arctic, deep-sea trenches, human plasma – we find plastic. The more we look, the more we find,” says Environmental Protection Agency (EPA) chemist Michaela Cashman, Ph.D., the lead author on a recent EPA-led study that developed a new method for identifying microplastics.2
Conclusions
Microplastics have infiltrated every part of the planet. They have been found buried in Antarctic sea ice, within the guts of marine animals inhabiting the deepest ocean trenches, and in drinking water around the world. Plastic pollution has been found on beaches of remote, uninhabited islands and has shown up in sea water samples across the planet. One study estimated that there are around 24.4 trillion microplastic fragments in the upper regions of the world’s oceans. Microplastics are spread widely in soils on land too and can even end up in the food we eat. Unwittingly, we may be consuming tiny fragments of plastic with almost every bite we take.9
EPA and other organizations are actively researching microplastics; however, there is admittedly much more work to be done including determining the short- and long-term effects on human health and the environment.
Additional Resources
HETI’s Certified Industrial Hygienists, Professional Engineers and Environmental Specialists are available to assist clients with a variety of services to help assess and/or characterize the safety and impact of microplastics in their organizations.
References:
1 Microplastics Research | US EPA
2 Making Microplastic Identification More Accessible | US
4 RemediationTechnology@products-bnp.com,
5 Assessing Effects of Nano- and Microplastics in Aquatic Environments | Science Inventory | US EPA
6 Microplastics – Eurofins USA
9 How microplastics are infiltrating the food you eat – BBC Future