President Obama and the U.S. Congress may not get along very well, but they just teamed up to give the country a welcome New Year's gift: no more microbeads.

Microbeads are tiny plastic specks that pose a big problem for aquatic ecosystems. Found in products from toothpaste to body wash, the miniature exfoliants easily drain into waterways, where they're eaten by fish and pass up the food chain.

After several states banned microbeads — starting with Illinois in 2014 — U.S. lawmakers drafted the Microbead-Free Waters Act of 2015 earlier this year. The bill is designed to phase out microbeads in consumer products over the next five years.

While Congress has grown increasingly divided in recent decades, microbeads have proven to be a rare source of bipartisanship. Not only was the bill co-sponsored by a Republican and a Democrat — U.S. Reps. Fred Upton, R-Michigan, and Frank Pallone, D-New Jersey — but it was unanimously passed by the U.S. House of Representatives on Dec. 7. It then went to the U.S. Senate, which also unanimously passed the measure on Dec. 18, before moving on to Obama's desk for presidential approval.

Obama finally signed the bill into law on Dec. 28, a major victory in the struggle against plastic pollution. The new law "prohibits the manufacture and introduction into interstate commerce of rinse-off cosmetics containing intentionally-added plastic microbeads," although this will happen in stages. The first steps take effect on July 1, 2017, when the production of certain microbead products becomes illegal, followed by more specific production and sales bans in 2018 and 2019.

microbeadsA sample of microbeads collected from Lake Erie in 2012 by the 5 Gyres Institute. (Photo: 5 Gyres Institute)

Global plastic production has exploded in the past 60 years, from 1.9 million tons in the 1950s to 317 million tons in 2012. On top of more obvious garbage like plastic bags and bottles, this includes minuscule microplastics — both the crumbs of larger debris and the intentionally tiny microbead exfoliants. These plastics contain toxins, due to their own non-biodegradable materials as well as chemicals they absorb from the environment. According to U.S. researchers, plastic debris accumulates pollutants like PCBs at up to 1 million times the levels found in seawater.

Whatever its size and wherever it's discarded, plastic pollution tends to collect in water bodies, where it can be eaten by animals that mistake it for food. This directly endangers wildlife in some cases — like when sea turtles eat plastic forks or seabirds eat cigarette lighters — but it may also raise more insidious risks as it sneaks up the food chain. A 2015 study, for example, found that many seafood samples contained small fragments of plastic, whose toxins are known to bioaccumulate.

Because microbeads are used in products like shampoo, body wash and toothpaste, they typically are washed into water sources like the Great Lakes, which hold one-fifth of Earth's fresh surface water. In 2012, a research cruise by the 5 Gyres Institute found 1.7 million pieces of microplastic in Lake Erie alone, revealing a density of plastic pollution that's even higher than most ocean samples.

"These beads wash straight down your drain after washing your face, and directly into your watershed," according to 5 Gyres, which has spent years campaigning against microbeads. "No sewage treatment system can capture them."

The new law is drawing widespread praise from environmental advocates, especially given its broad definition of microbeads. By defining them as "any solid plastic particle that is less than five millimeters in size and is intended to be used to exfoliate or cleanse the human body or any part thereof," it closes a potential loophole by preventing manufacturers from simply switching to different types of plastic.

"It's a banner day for Lake Michigan and the Great Lakes — we now have a bipartisan law on the books to cleanse dirty microbeads from all our nation's waters," Upton says in a statement released this week. "Microbeads may be tiny plastic, but they are wreaking big time havoc in our waters. We came together, Republicans and Democrats, and got the job done."

Russell McLendon ( @russmclendon ) writes about humans and other wildlife.