As editor of All along we've been reading about how plastic marine debris will float in the ocean for centuries, killing wildlife and causing havoc.
Now the latest problem is that the plastic won't last forever -- it's degrading faster than scientists expect, and the chemicals being left behind will kill more wildife and cause more havoc.
The news comes from a widely-covered speech by Katsuhiko Saido, a chemist at Nihon University in Chiba, Japan, who led a team of scientists that looked at the marine debris problem. Saido spoke this week at a meeting of the American Chemical Society in Washington.
According to a report from National Geographic News, the team collected ocean water samples from around the world and found that they all contained derivatives of polystyrene.
The toxic compounds the team found don't occur naturally in the ocean, and the researchers thought plastic was the culprit.The scientists later simulated the decomposition of polystyrene in the sea and found that it degraded at temperatures of 86 degrees Fahrenheit (30 degrees Celsius).
Left behind in the water were the same compounds detected in the ocean samples, such as styrene trimer, a polystyrene by-product, and bisphenol A, a chemical used in hard plastics such as reusable water bottles and the linings of aluminum cans.
The National Geographic News version of the story is one of the more complete that I've seen. It notes that water temperatures in much of the ocean are much cooler than 86 degrees Fahrenheit.
A few weeks ago, if someone had told me that scientists had discovered that plastic marine debris was breaking down in the ocean, I would have thought that was good news.
Apparently I would have been wrong.
Really, the best solution to this problem is to stop creating marine debris in the first place -- and to work toward a solution to clean up what's already out there.
Comments (3)
It should not surprise anyone -- well anyone who has worked with PVC pipe like a few million home owners, gardeners and plumbers; or anyone who has picked up old brittle plastic bags by the side of the road -- to hear that plastic breaks down. Ultra violet light has long been known to break the bonds in common polymers, hence the addition of UV stabilizers to many plastics. The stabilizers work by absorbing the UV rays, but that eventually breaks the stabilizers down, then the UV is absored by the polymers and they start breaking down.
Take a look at the taillights in older cars that have spent a lot of time in the sun -- you will notice that they have become hazy -- another sign of breakdown.
The best place for unwanted (i.e. no recycle value) plastics is in a modern landfill.
Of course, too many people are sloppy pigs, so we end up with enormous masses of plastics in the ocean. People -- too irresponsible to properly use useful items like plastics.
Posted by Bill | August 20, 2009 8:01 PM
Posted on August 20, 2009 20:01
Contrary to some media reports stemming from an August 19 press conference (and news release associated with it) during the American Chemical Society National Meeting in Washington, the chemical styrene is not a known human carcinogen and polystyrene plastic neither contains, nor does it break down into bisphenol A (BPA).
The press conference focused on new, as-yet-unpublished research led by Katsuhiko Saido of Nihon University, Chiba, Japan, suggesting that plastics – notably polystyrene -- in the oceans break down, leaving products of their decomposition, including styrene monomer and styrene dimers and trimers. During the press conference, no mention was made of styrene’s potential carcinogenicity, nor was there any mention of a relationship between polystyrene and BPA, although one of the researchers did cite BPA as a potential breakdown product of PET (polyethylene terephthalate) plastic.
Styrene monomer is the building-block chemical from which polystyrene is made. No authoritative body anywhere in the world considers styrene to be a known human carcinogen. Any specific statement concerning the researcher’s findings about polystyrene would be premature at this time since we have not seen and are not familiar with this work. -- Joe Walker for the Styrene Information and Research Center, Arlington, Va., www.styrene.org
Posted by Joseph Walker | August 21, 2009 11:57 AM
Posted on August 21, 2009 11:57
Looks like more bolonium. Scientists should know how to quantify and compare. How much trimer, and why is this degradation product singled out? How do they know that it is toxic, how does it affect fish and people, and at what concentrations? (Look at the hordes of people who apply botulism toxin to their skins, and the others who subject themselves to solar degradation.)
How soluble is the trimer in water (I doubt that it is significant) and does it degrade further?
Maybe he covered all these things (I didn't read the whole article, but am judging from your report), but somehow I doubt it.
The whole 30 C issue is suspect, not only because the oceans are colder, but because PS does not degrade at such temperatures -- far below extrusion/molding temps, and below even ambient temp in many warehouses and trucks. However, PS foam floats and is thus exposed to UV degradation. Did they consider or simulate this?
What about PE, which is a common target of the ocean police?
As for the bisphenol A, this has nothing to do with polystyrene, and its presence is hard to explain, as even if its residual amount separated in salt water from PC, that resin is too costly to be used in disposable packaging, so the pigs can't even throw it away.
Saido comes with high credentials, so he should know better. Nihon U is the largest U in Japan (over 60K students), and Saido (age 62) is a N-U graduate, and an assoc professor in the college of pharmacy. His 31 listed publications start with one entitled "Plastics as Sources of Environmental Pollutants," and are concentrated in this field: endocrine disrupters (BPA?), polystyrene and phthalates. He knows a lot about PS degradation, so he went looking for it.
It all looks like more junk science with a university blessing, taking advantage of a scared public's chemophobic fears.
Allan Griff
Posted by Allan Griff | August 22, 2009 9:04 AM
Posted on August 22, 2009 09:04