An outright ban on the common use of plastic
"microbeads" from products that enter wastewater is the best way to
protect water quality, wildlife, and resources used by people, a group of
conservation scientists suggest in a new analysis.
These microbeads are one part of the microplastic problem in
oceans, freshwater lakes and rivers, but are a special concern because in many
products they are literally designed to be flushed down the drain. And even at
conservative estimates, the collective total of microbeads being produced today
In an article just published in the journal Environmental
Science and Technology http://pubs.acs.org/journal/esthag,
scientists from seven institutions say that nontoxic and biodegradable
alternatives exist for microbeads, which are used in hundreds of products as
abrasive scrubbers, ranging from face washes to toothpaste. Around the size of
a grain of sand, they can provide a gritty texture to products where that is
"We're facing a plastic crisis and don't even know
it," said Stephanie Green, the David H. Smith Conservation Research Fellow
in the College of Science at Oregon State University, and co-author of this
"Part of this problem can now start with brushing your
teeth in the morning," she said. "Contaminants like these microbeads
are not something our wastewater treatment plants were built to handle, and the
overall amount of contamination is huge. The microbeads are very durable."
In this analysis, and using extremely conservative
methodology, the researchers estimated that 8 trillion microbeads per day are
being emitted into aquatic habitats in the United States - enough to cover more
than 300 tennis courts a day. But the other 99 percent of the microbeads -
another 800 trillion - end up in sludge from sewage plants, which is often
spread over areas of land. Many of those microbeads can then make their way into
streams and oceans through runoff.
"Microbeads are just one of many types of microplastic
found in aquatic habitats and in the gut content of wildlife," said
Chelsea Rochman, the David H. Smith Conservation Research Postdoctoral Fellow
at the University of California/Davis, and lead author on the analysis.
"We've demonstrated in previous studies that
microplastic of the same type, size and shape as many microbeads can transfer
contaminants to animals and cause toxic effects," Rochman said. "We
argue that the scientific evidence regarding microplastic supports legislation
calling for a removal of plastic microbeads from personal care products."
Even though microbeads are just one part of the larger
concern about plastic debris that end up in oceans and other aquatic habitat,
they are also one of the most controllable. With growing awareness of this
problem, a number of companies have committed to stop using microbeads in their
"rinse off" personal care products, and several states have already
regulated or banned the products.
The researchers point out in their analysis, however, that
some bans have included loopholes using strategic wording. Many microbeads are
used in personal care products that are not "rinse off," such as
deodorants and cleaners. And some regulations use the term
"biodegradable" to specify what products are allowed - but some
microbeads can biodegrade just slightly, which may allow their continued use.
If legislation is sought, "new wording should ensure
that a material that is persistent, bioaccumulative, or toxic is not added to
products designed to go down the drain," the researchers wrote in their
"The probability of risk from microbead pollution is
high, while the solution to this problem is simple," they concluded.
All the authors on this study were funded by the David H.
Smith Postdoctoral Research Fellowship Program, which works to develop
science-based policy options for conservation and environmental issues. Other
collaborators were from the University of Wyoming, University of
California/Berkeley, Wildlife Conservation Society, College of William and
Mary, and Georgia State University.