Microbeads are manufactured solid plastic particles of less than one millimeter in their largest dimension. They are most frequently made of polyethylene but can be of other petrochemical plastics such as polypropylene and polystyrene.
They are used in exfoliating personal care products, toothpastes, and in biomedical and health-science research.
Microbeads can cause plastic particle water pollution and pose an environmental hazard for aquatic animals in freshwater and ocean water. In the United States, the Microbead-Free Waters Act of 2015 phased out microbeads in rinse-off cosmetics by July 2017. Several other countries have also banned microbeads from rinse-off cosmetics, including Canada, France, New Zealand, Sweden, Taiwan, and the United Kingdom.
Types
Microbeads are manufactured solid plastic particles of less than one millimeter in their largest dimension when they are first created, and are typically created using material such as polyethylene (PE), polyethylene terephthalate (PET), nylon (PA), polypropylene (PP), and polymethyl methacrylate (PMMA). The most frequently used materials are polyethylene or other petrochemical plastics such as polypropylene and polystyrene. Microbeads are commercially available in particle sizes from to . Low melting temperature and fast phase transitions make them especially suitable for creating porous structures in ceramics and other materials.
Regional differences
The parameters for what qualifies as a microbead change subtly based on location and the corresponding legal jurisdiction; minor distinctions in the definition may be encountered from one country to another. For example, the U.S. official definition for a microbead, as per the Microbead-Free Waters Act 2015 laid out by Congress, is "any solid plastic particle less than 5 millimeters in size that was created with the intention of being used to exfoliate or cleanse the human body." On the other hand, Environment and Climate Change Canada (ECCC), the governmental agency responsible for Canada's microbead ban, settled on a definition which includes only plastics with diameters between 0.5 microns and 2 millimeters; although a diameter range of 0.1 microns to 5 millimeters was initially proposed, the definition was revised after consultation with members of industry and meeting resistance from plastic manufacturers who claimed that many of their raw materials (for example, those needed to make bottles for soft drinks) would be covered by the ban, affecting their business unduly. While the intent clause in the American law leaves open a loophole for producers of other equally frivolous and environmentally destructive products to potentially exploit in the future—as long as their use case does not involve grooming or personal care—the Canadian law has already been criticized publicly for its overly restrictive nature, which could cripple its efficacy in practice; in response to the revised definition, concerned conservation groups (including the Sierra Club of Canada) have raised warnings about the law's wording, fearing that Canada may "become a dumping ground for [those] microbead-containing products" which are now banned in the United States.
Use
Microbeads are added as an exfoliating agent to cosmetics and personal care products, such as soap, facial scrub, and toothpastes. They may be added to over-the-counter drugs to make them easier to swallow. In biomedical and health science research, microbeads are used in microscopy techniques, fluid visualization, fluid flow analysis, and process troubleshooting.
Sphericity and particle size uniformity create a ball-bearing effect in creams and lotions, resulting in a silky texture and spreadability. Smoothness and roundness can provide lubrication. Colored microspheres add visual appeal to cosmetic products.
Environmental effects
When microbeads are washed down the drain, they subsequently pass unfiltered through sewage treatment plants and make their way into rivers and canals, resulting in plastic particle water pollution. A team of researchers from Uppsala University published and subsequently retracted a study (at least one researcher was found to have fabricated results) which stated that one of the various animals affected by microbeads was perch, a freshwater fish. The beads can absorb and concentrate pollutants like pesticides and polycyclic hydrocarbons. Microbeads have been found to pollute the Great Lakes in high concentrations, particularly Lake Erie. A study from the State University of New York, found anywhere from 1,500 to 1.1 million microbeads per square mile on the surface of the Great Lakes.