Julie Lawson, director of the Trash Free Maryland Alliance, has a new weapon in her fight against waterborne plastic pollution. It’s a glass jar filled with brown water from the Chesapeake Bay, and she takes it everywhere she goes.

She takes her jar to community events and meetings with grant makers. The Maryland General Assembly is next on her list. People have asked to borrow it.

“I think I need a check-out system,” Lawson said.

The water in the jar looks like over-steeped tea, swirled with dark bits of fragmented leaves. The content that matters most to Lawson’s cause is quite tiny, but still visible: colored specks of plastic. Lots of them.

Last November, these plastic bits were floating on the surface of the Chesapeake Bay. Lawson collected them during a four-day “trash trawl” that took place in November with help from the 5 Gyres Institute, a nonprofit organization that works to reduce plastic pollution in the world’s oceans.

The world’s oceans have five large, rotating currents called gyres, where debris — mostly plastic —concentrates. A study led by the 5 Gyres Institute has found that at least 6 trillion pieces of plastic with a total weight of approximately 270,000 tons are floating on the surface of the world’s oceans.

Scientists and activists in the Chesapeake region are increasingly concerned about conditions closer to home.

“We know the Bay’s tributaries are polluted with plastic and we have some understanding of plastic pollution in the ocean, but very little has been done to look at plastics in the Bay,” Lawson said. “We wanted to see what was out there.”

People often think of plastic pollution as bottles and bags clumped along shorelines and storm drains. They might recall images of birds and turtles that have been tangled in plastic or swallowed it.

But eyesores and physical hazards are just part of the problem. That plastic trash we see makes its way into the water, and over time, breaks down into tiny bits.

Plastic often contains toxic components, which are part of the basic structure and are added for special purposes. These can leach into the water or be swallowed by wildlife, where they have the potential to work their way up the food chain to affect human health.

Toxins in the water or sediment from other sources can also attach to plastic debris and travel with it.

Plastics are made with different combinations of chemicals and their composition determines what they may release, said Laura Johnson, who leads the Trash Free Waters program for the EPA. “But if these plastics are in the water releasing toxins, that’s a problem for water quality. If organisms are eating them, does that mean it’s a risk for us, too?”

There are more questions than answers. The problem is worsened because most waterborne plastic persists in a form that most people rarely see — tiny bits called microplastics.

Some plastics are designed to be small, like the beads used as abrasives in toothpaste and facial scrubs, or the fibers in fleece clothing and cigarette butts. But bulky items break down into microplastics, too.

“Plastic is a synthetic polymer that breaks and cracks and get abraded,” said Lance Yonkos, a professor at the University of Maryland who has studied microplastics in Chesapeake tributaries. “If you start out with a soda bottle, in a year you could have thousands of microplastics.”

Plastic doesn’t degrade like organic material, so it stays in the water for a long time. “It floats around, it goes to the bottom, it gets eaten,” Yonkos said. “And it hasn’t been demonstrated yet that this stuff goes away. The vast majority of microplastics from the past few decades may still be a polymer in some form and still out there in the environment.”

The 5 Gyres study estimates that microplastics in the world’s oceans — smaller than one-fifth of an inch — have accumulated into a total weight of at least 35,540 tons.

In the past, Lawson used water samples drawn from the Pacific Ocean to raise awareness of microplastics with people in the Chesapeake region. But for most audiences, the problem seemed vast and far away.

After Trash Free Maryland received a grant from the Chesapeake Bay Trust last fall, Lawson arranged a partnership with the 5 Gyres Institute to conduct sampling in the Bay. They sailed out of Anne Arundel County on four consecutive days in November, slowly pulling a manta trawl through the surface of the water.

The trawl gets its name because it looks like a manta ray built from metal parts. Two “wings” support a central box with an opening that collects the water it moves through. The water is filtered down a long tapering net, which resembles a tail, made from very fine mesh.

The sample is eventually collected from a narrow sack at the end of the net. Large debris is removed with a sieve.

On the first day, calm waters allowed more plastics to rise to the surface. “We had optimal conditions,” Lawson said.

Jeff Corbin, the EPA’s senior adviser on the Chesapeake Bay, was on board to see what they’d find. He didn’t expect much, because microplastics in the oceans have been documented in places where currents tend to collect them. Bay water moves differently, without bringing debris to predictable locations.

Corbin was surprised by what the team retrieved. “They emptied the sample into a bucket so things could float to the top, and there were all these colored specks — white, blue, pink,” Corbin said. “It looked like little paint chips floating all over the surface of the water.”

Stiv Wilson of the 5 Gyres Institute, who directed the trash trawl, said he’d seen samples with similar densities drawn from the Pacific Ocean.

“I thought microplastics were more of an offshore problem for the ocean,” Corbin said. “I was very surprised to see it two miles offshore in the Chesapeake Bay.”

Weather conditions varied over the next few days and not every sample delivered dramatic results.

“We didn’t always have the eye-popping density you see in the ocean, but it was still compelling to see the presence of microplastics on such a very consistent level,” Lawson said.

The trawl was not a scientific study but a snapshot that Lawson hopes will draw more attention and funding to the problem.

Little research has taken place on microplastics in the Bay so far and there is no data to allow an accurate comparison of findings in the Bay with those in other places.

The study by Yonkos at the University of Maryland, conducted in partnership with the U.S. National Oceanic and Atmospheric Administration, California Department of Health and the I.M. Systems Group, looked at the density and weight of microplastics in four of the Bay’s Maryland rivers: the Patapsco, Magothy, Rhode and Corsica.

Researchers collected 15 samples from each river during 2011. They found more microplastics in the Magothy and Patapsco Rivers — which are closer to urban areas — than in the Rhode or the Corsica.

“This is a good, sound, first cut that confirms exactly what you’d expect,” Yonkos said. “When you get close to denser populations, you find more plastics. It’s also suggestive of abundance after big rains, but that’s a topic that needs more work.”

Environmental groups and some governments in the Bay region are already trying to reduce plastics in local waterways.

Most of these groups are doing the hard physical work of collecting the trash after it gets in the water.

Trash traps have been installed in the Anacostia River watershed. A “trash wheel” in Baltimore lifts debris out of the Jones Falls before it reaches the Inner Harbor. The Alice Ferguson Foundation has been sponsoring cleanups and related projects for a trash-free Potomac for more than 20 years

Volunteers with Clean Virginia Waterways have also been at work for two decades. “Plastics are the majority of what we find,” said Clean Virginia Waterways director Katie Register. “Cigarette butts usually take the lead. People don’t think of them as plastic, but those white fibers that look like cotton are actually plastics with toxins in them.”

Register, who recently helped develop a marine debris reduction plan for Virginia, said cleanups are one necessary part of the solution. Consumers also need to make different choices by using less plastic and asking corporate producers to use less, too.

“There is a big role for corporations in reducing the amount of disposables,” Register said.

In October, California became the first state to ban plastic bags. About 13 million bags are distributed in the state each year. The ban will be implemented first in large grocery stores and over the next year be required in smaller stores.

Local governments on Hawaii’s four main islands have also banned plastic bags.Proponents of the bag bans point to these two examples and note that if California, the nation’s largest state, can institute such a ban, it could happen in other states.

Some governments have passed bills that reduce the use of plastic bags and bottles by instituting a fee, but there is debate over how well such programs achieve their intended goals. The District of Columbia set a 5-cent fee on disposable bags, both paper and plastic, that took effect in 2010.

Lawson would like to see Maryland institute a statewide law to reduce or ban the use of plastic bags and hopes that the jar of plastic-riddled water from the Chesapeake Bay will help make the case. “This shows that it’s a local problem,” Lawson said, “not just some monster from the deep.”