Ocean Safe Biodegradeable Plastic

VIMS Makes Ocean-safe Biodegradable 'Plastic' from Bacteria

For one week last August, Hampton Roads followed the progress of a sickly young sei whale as she swam erratically in the rivers and creeks of the Chesapeake Bay before she finally died.

A necropsy found the whale had ingested a sharp, rigid shard from a plastic DVD case, which sliced her stomach lining and prevented her from feeding.

The news that a bit of plastic trash killed a great whale saddened but didn't surprise the Stranding Response Team at the Virginia Aquarium and Marine Science Center in Virginia Beach.

As the aquarium's research coordinator Susan Barco told National Geographic earlier this month, "It was a preventable death."

Barco was referring to the proper disposal of trash before it reaches the open ocean.

But to marine biologists at the Virginia Institute of Marine Science (VIMS) in Gloucester Point, there's another reason why that whale didn't have to die.

It's called polyhydroxyalkanoates — or PHAs.

PHAs are benign granules naturally produced by bacteria throughout nature that can mimic many of the useful properties of plastics, but in a marine environment biodegrade into water, carbon dioxide and other simple molecules.

Just like plastics, these biopolymers can be fashioned into microbeads, pulverized into powder or melted and extruded into molds — perhaps even for a DVD case.

But unlike plastics, which last forever in the environment, breaking down into smaller and smaller bits over the years, PHAs get gobbled up quickly by aquatic microbes and return to nature.

"So it's kind of like the perfect material, because it's already naturally found in the environment," said Kirk Havens, director of the Coastal Watersheds Program at VIMS.

Ghost pots

Several private companies are exploring the commercial potential of PHAs to replace at least some of the nearly 300 million tons of plastics produced globally every year, much of it ending up in landfills or loosed upon the world.

A recent study found that about 300,000 tons of plastic pieces large and small are floating on the world's oceans. That's considered a conservative estimate, in part because it doesn't include the microplastics that escaped researchers' survey nets, or the "potentially massive" amounts of plastics embedded in beaches or the seabed, ingested by organisms or simply suspended in the water column. These findings appeared last month in Plos One, an international, peer-reviewed online science journal.

VIMS, too, is exploring commercial uses for PHAs, from microbeads for skin care products to escape panels for crab pots.

They first stumbled on the concept a few years ago while mapping out different sediment types on the bottom of the Chesapeake Bay using side-scan sonar.

Curious to find out just how many of these "ghost pots" were littering the bay and what their impact on the environment and bay fisheries is, the researchers hired watermen to go out and pull them up. Over four winters, the watermen found more than 34,000 lost traps in the bay, with nearly 32,000 animals still trapped inside.

According to VIMS biologist Kory Angstadt, Virginia watermen work about 300,000 blue crab pots every year, losing an average of 60,000 of them to storms, accidents or abandonment.

His colleague, Donna Bilkovic, said they estimate as many as a million blue crabs die every year inside ghost pots in Virginia's portion of the bay, with an annual impact to the fishery of about $300,000. They're partnering now with the National Oceanic and Atmospheric Administration (NOAA) on a two-year field study to refine their figures and come up with a baywide assessment of the impacts of ghost pots on blue crabs and other marine species.

The biologists believe one solution to the crab carnage is to use PHAs to make biodegradable escape panels, or rings, for crab traps. They came up with a design, and soon expanded into escape panels for lobster, fish and other trap types.

VIMS' affiliate, the College of William and Mary in Williamsburg, patented the use, then licensed the technology to a Richmond-based company called Mobjack Binnacle Products, which promotes the biopanels' potential for "fuller harvests for watermen."

The panels are pricier than regular plastic versions (roughly 20 cents for a plastic crab pot panel, for instance, versus $1.50 for the biopanel on Mobjack's site), but the scientists say the cost should drop once manufacturing picks up, and tout the long-term environmental and economic benefits.

The biopanels degrade only when in the water. So each time a pot is hauled out, even for a moment, Havens said, ultraviolet light knocks back the bacteria consuming it, interrupting the process.

"So the panel lasts a lot longer," said Havens. "But if you lose the pot and it sits on the bottom out of the sunlight, then the panels get consumed a lot faster."

Microbeads, major problems

Around the same time as the biopanel work, tiny plastic microbeads used in a host of personal care products began popping up in science literature and the news, under fire for polluting waterways and damaging wastewater treatment plants as they essentially sand-blast through the systems.

Microbeads are used in products from exfoliants to toothpastes to laundry detergent. Some states and municipalities as well as federal agencies are now trying to ban their use in cosmetics and toiletries.

Plastic microbeads are especially troublesome in aquatic environments, Havens said, because they float and attach to other floating pollutants, such as PCBs (polychlorinated biphenyls), making them a literal poison pill when ingested by various organisms.

When those organisms get eaten by larger ones, the poisons and the plastics aggregate up the food chain, even to the family dinner plate. Once they become part of the food web, VIMS says, microplastics are there to stay.

The biologists quickly recognized the potential of ocean-safe PHAs for the multibillion-dollar cosmetics industry.

Using a $60,000 grant from the Virginia Innovation Partnership in 2013, they began to develop biodegradable microbeads made from soil-dwelling bacteria as a material substitute for the synthetic versions. The tiny biobeads range in size from the gritty width of a human hair to the consistency of talcum powder.

Jason McDevitt at William and Mary's Technology Transfer Office said the college has filed for a method-of-use patent on their particular formulation.

"We don't have the only possible alternative, but we have an alternative that we think is a very good one," McDevitt said. "Because it's a genuine drop-in replacement without the problems of others, like crushed walnuts."

They're also working with the Hampton Roads Sanitation District to determine how completely their microbeads will biodegrade in the wastewater treatment system.

Biobeads would also come at a cost, although Havens estimates it would be minimal — perhaps adding 2 cents to the price of a 12-ounce, $8 bottle of lotion.

VIMS is expanding its PHA work into other areas, he said, including biodegradable shotgun wads, which are produced by the billions every year, get used by duck hunters and are turning up in increasing numbers during beach cleanups. Seabirds such as the albatross spot the spent wads floating in the water and, mistaking them for squid or other prey, gobble them up.

Source: Daily Press

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