Brave new world: nature making new type of rock from plastic waste

news
10 June 2014

A new type of rock created by melted plastic trash has been discovered by researchers on a beach in Hawaii, Live Science reported on Monday.

The new rock material, dubbed by scientists as plastiglomerate, is the result of melted plastic trash on beaches mixing with sediment, basaltic lava fragments and organic debris such as shells.

Estimated to be able to persist in the environment for hundreds to thousands of years, plastics are notorious for environmental degradation as they do not break down easily.

At Hawaii's Kamilo Beach, Captain Charles Moore, an oceanographer with the Algalita Marine Research Institute in California, found that plastic, if melted, can actually become one with rocks, sediment and other geologic materials.

"He found some plastic had been melted to rocks, and other pieces of natural material had also been stuck on it," said the study's lead author Patricia Corcoran, a geologist at the University of Western Ontario in Canada.

"He didn't know what to call it. It's possible other people have found [the plastic conglomerates] at other locations before Captain Moore did, but nobody had thought to report it or identify it," Corcoran said.

Two types of plastiglomerates, in-situ and clastic, were discovered by the researchers at Kamilo Beach.

In-situ plastiglomerate is rarer than the clastic variety, and forms when "plastic melts on rock and becomes incorporated into the rock outcrop," Corcoran told Live Science, adding that the melted plastic can also get into the rock vesicles, or cavities.

Clastic plastiglomerates are loose rocky structures, composed of a combination of basalt, coral, shells, woody debris and sand that have been glued together by melted plastic.

After finding plastiglomerates at Kamilo Beach, Moore hypothesized that molten lava had melted the plastic to create the new rock.

However, the researchers found that lava had not flowed in that area since before plastics were first invented.

"The researchers then concluded that people inadvertently created the plastiglomerates after burning plastic debris, either intentionally to try to destroy the plastic or accidentally by way of campfires," Corcoran said. "The team believes the material could be present at a lot of other beaches around the world, particularly in areas where people camp or live."

"I would say that anywhere you have abundant plastic debris and humans, there will probably be plastiglomerates," Corcoran said.

The plastiglomerate is described in the journal GSA Today.

 





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