Microplastic refers broadly to all solid plastic particles of 5mm or less found as litter in oceans and other waterways. Solid, plastic microbeads are just one contributor to microplastic litter. The leading sources of microplastic litter include particles from the wearing of vehicle tires washed off into roads, fibers from the washing and breakdown of textiles, and the breakdown of larger plastic litter, especially discarded packaging.
Studies from around the world, including research by independent scientists and environmental advocacy groups, have shown that microbeads from all sources, not just personal care products, are among the smallest contributors to microplastic litter in marine environments. Microbeads from personal care products have been estimated to make up 0.1-1.5% of all sources of microplastic litter emitted to the North Sea marine environment. In a detailed assessment of all primary and secondary microplastic emissions in Norway, tire dust was likely the largest contributor to microplastic concentrations in the Baltic Sea, whereas consumer products were likely the smallest contributor. In Denmark, 0.9% of the total microplastic emission to the aquatic environment was from primary microplastics and only 0.1% from cosmetic products. Tire dust contributed 60% of the total microplastic emission. Scientists also reported that land-based microplastic emissions to the marine environment were dominated by tire dust.
Microplastics detected in monitoring studies in 2018 are of secondary origin (i.e., fragments of larger plastic items that have degraded or fibers unintentionally released from clothing). Sources of secondary microplastics are important to understand for effective policy or mitigation measures to reduce microplastics in the environment. According to the study authors, a great deal of regulatory focus has been placed on primary microplastics, yet reducing or banning them, including cosmetic microbeads, may only have a limited impact on reducing overall environmental microplastic loads. A similar conclusion was reached in 2015.
Available data indicate that WWTPs remove a significant proportion of microbeads. Primary treatment processes in WWTPs can remove an average of 65% of the total microplastic inflow load. Secondary and tertiary treatment options can remove up to 99% of the total microplastic inflow load. A study of Danish WWTPs predicted environmental release rates of only 0.3% of the incoming microplastic mass. Since most microplastics detected in WWTP discharge are plastic fibers and fragments with microbeads representing only a small portion, even smaller amounts of microbeads are released into the environment.
Even though microbeads can move through the size exclusion meshes used in the treatment plants, many are likely to float due to their density and subsequently removed by skimmers in the primary treatment process. If microbeads are not floating, they will sink to the bottom of settling tanks or clump together with the help of chemicals in order to be removed. Therefore, only a very small fraction of the microbeads would remain in the aqueous treatment process and be released into the marine environment with discharge water.
Microplastics have been detected in fish, invertebrates and avian species. However, consistent with water and sediment microplastic occurrence data, the most significant proportion of microplastics detected is made up of fibers and fragments, with only a small proportion being microbeads. A study of 400 fish from the North Sea yielded two microplastics in a single fish. Fish and plankton sampled over the course of 30 years in the Baltic Sea showed no significant increases in internal microplastic concentration. Approximately 20% of the fish sampled contained microplastics, and 93% of these microplastics were fibers.
The ingestion of microplastics must be considered in conjunction with defecation rates for a meaningful interpretation of the presence of microplastics in organisms. Few laboratory microplastics exposure studies on fish and invertebrate species examine defecation rates, particularly at concentrations similar to those found in the environment. Laboratory studies demonstrated low microplastics gut retention times in fish and invertebrates, as concluded in other studies from 2013, 2014 and 2016, providing further evidence that accumulation will be minimal.
While microplastics transfer into the environmental food chain has been demonstrated in laboratories, artificial conditions used in those studies are not representative of environmental conditions, and any study results should be interpreted with caution. The transfer of microplastics into the food chain has yet to be proven.
Effective studies with microplastics have explored a range of endpoints, including survival, growth, reproduction, molting and biochemical endpoints. However, assessing potential harm from microplastics in the environment must be risk-based because occurrence does not necessarily equate to impact. Even when an effect is seen in a laboratory, it does not mean the same effect will occur in a natural environment. There is limited evidence to suggest that microplastics are causing harm in a natural environment, which is supported by another ecotoxicological risk assessment of microplastics that revealed levels of microplastics found in the natural environment do not exceed levels shown to impact wildlife.
Personal care products are part of an innovative industry that supports reducing plastic litter in waterways. Manufacturers continue to closely follow ongoing scientific research to better understand microplastics’ sources, scope and potential environmental effects.
Studies in 1988, 2013 and 2016 of the possible correlation of persistent, bioaccumulative and toxic substances (PBTs) in wild species with environmental levels of microplastics provide little proof that microplastics are responsible for observed contamination of organisms. Several studies in 2008 and 2017 have observed less transfer from plastics than from other more abundant and naturally occurring particles (e.g., sediment), suggesting that the transfer of contaminants from plastic is not significant. The 2018 critical review of available studies concluded that significant evidence for microplastics acting as a vector for PBTs into organisms has not yet been demonstrated. Laboratory and modeling evidence suggests that the impact of this exposure pathway is minimal.
Reformulating a product can be complicated, time-consuming and challenging because it is not as simple as switching one ingredient for another. A variety of experts must first confirm that any new ingredient meets all regulatory, safety and environmental requirements. Before a reformulated product can go to market, companies must ensure that alternative ingredients:
– meet federal and state safety regulations,
– are available in sufficient quantities and
– can be built into existing or new manufacturing processes.
Learn more about the product reformulation process.
In the U.S., cosmetics are regulated by the U.S. Food and Drug Administration (FDA) under the Federal Food, Drug, and Cosmetic Act (FD&C Act) and the Fair Packaging and Labeling Act (FPLA). All cosmetics products and their ingredients are subject to the same safety requirement under the FD&C Act – companies have a legal responsibility to ensure that their products and the ingredients used in them are safe for consumers and must maintain detailed records substantiating the safety of each product before they are marketed to the public. Product safety is also established though strict adherence to the principles of Quality Assurance and Good Manufacturing Practices.
Peer-reviewed research (i.e., studies validated through the accepted scientific standard of review and critique by fellow scientists) has not shown that plastic microbeads used in cosmetics and personal care products harm humans. Additionally, the FDA stated, “… we do not have evidence suggesting that plastic microbeads, as used in cosmetics, pose a human health concern.”
Product safety and environmental stewardship is a priority for personal care products companies. The industry is committed to working with environmental and conservation NGOs and scientists, among others, to do its part in finding pragmatic solutions to plastic litter in oceans and waterways – for the benefit of consumers and the marine environment. The personal care products industry took swift, early action on environmental protection by addressing concerns about microbeads, even though microbeads make up a very tiny fraction of microplastic litter in waterways. This included voluntarily removing microbeads from rinse-off personal care products. The industry worked with NGOs, lawmakers and others to advocate for the Microbead-Free Waters Act, which took effect nationwide in July 2017. The ban also applied to products that are both cosmetics and over-the-counter (OTC) drugs, such as toothpaste, as of July 1, 2018. Cosmetics and personal care product companies work with stakeholders across the globe to address microplastic litter, investing in research and initiatives to comprehend and help solve the problem. Real solutions to plastic and microplastic in waterways must address the true, leading sources of this litter: larger plastic debris that harms wildlife by ingestion and entanglement.
National Center for Biotechnology Information (NCBI), Scientific Research, ScienceDirect, and Publishing (SCIRP), and American Chemical Society (ACS)