Biodegradable plastics, often found in bottles and plastic bags, may not be part of the solution to ocean pollution as once marketed, according to a United Nations report published Monday, because they don’t break down well in marine environments.
The report, written by the UN’s top environmental scientists, says although biodegradable plastics were specifically designed to “be more susceptible to degradation,” they won’t solve the problem of litter in oceans because most plastic is extremely durable.
Plastics that break down in the environment were once thought of as an alternative that could possibly reduce the amount of waste in the ocean, but the rate at which they break down depends heavily on environmental conditions, the report stated.
There is also a lack of scientific evidence that biodegradation will occur any more rapidly than unmodified polyethylene, which is non-biodegradable, it said.
In ocean settings, the principal weathering agent is through UV irradiation, which is most pronounced on shorelines. Once the plastic is in the water, it is difficult to estimate the extent of biodegradation, but it is considered to be “extremely slow” due to decreased UV exposure and lower temperatures and oxygen levels, the report said.
The report also says that many biodegradable plastics require temperatures found in industrial composters — around 122 degrees Fahrenheit — “to breakdown completely into its constituent components of water, carbon dioxide, methane, on a reasonable or practical timescale.”
To read the full story, visit http://www.newsjs.com/url.php?p=http://abcnews.go.com/US/breakdown-biodegradable-plastics-ocean-extremely-slow-report/story?id=39345322.