Tag Archives: biodegradability

Story shines light on new, but controversial, degradable plastic.

Story shines light on new, but controversial, degradable plastic.

Posted by Evan Beach at Apr 16, 2010 09:30 AM | Permalink

An article in The Telegraph is one of the few media stories to focus on the ongoing controversy about so-called ‘oxo-degradable plastics.’

ShareThis

A public relations battle has erupted between different parts of the plastics industry over a new kind of degradable plastic.  Manufacturers that produce plastics from starch, sugar and other biological sources challenge claims about the environmental benefits of the new plastics.  They are pitted against companies that make the chemical additives involved. Both of these parties have financial interests at stake.

The Telegraph brings an unbiased voice to the debate by reporting on a new British government-funded scientific review.  The government report is not a “study” in the usual sense – no experiments were done by the authors – rather it is a summary of the work of dozens of scientists from around the world.

The article does an excellent job of covering most of the major issues involved. But, the reporter could have done more to highlight areas where there is uncertainty due to a lack of scientific evidence one way or the other.

The oxo-degradable technology involves adding small amounts of a metal-based additive that make plastics sensitive to the damaging effects of oxygen.  It can be added to everyday plastics like polyethylene (PE) that ordinarily are highly stable.  According to the government report, there is no question that plastics containing the additive can break down in the presence of light and heat, whereas without the additives the plastics persist.

But beyond that, there is a great deal of uncertainty. In particular, do the oxo-degradable plastics break down when buried in soil or in landfills?  Will microorganisms attack and digest the carbon in the plastic to make carbon dioxide? Some biodegradable plastics  – like polylactic acid (PLA) – do this without additives.

The Telegraph highlights many of the concerns raised by the government review.  For example, oxo-degradable plastics could disrupt plastic recycling facilities, might persist in a landfill, could break down too slowly to have any impact on littering and the small fragments might harm wildlife. The article also reports on product labels that might lead a consumer to dispose of the plastics in improper ways.

What the reporter could have clarified is the state of the science. The review emphasizes that its major limitation is the “lack of hard evidence produced by systematic, well-controlled studies carried out by independent parties.”  In other words, the jury is still out on many of the key issues.

The reporter mentions this uncertainty in the beginning, but only clearly communicates the lack of research with respect to bioaccumulation of plastic fragments in animals.  It would have been helpful to explain that there is not enough science to judge the other environmental issues as well.  The report found that not enough research had been done to determine whether the plastics could be degraded by microbes or break down when buried in a landfill. Similarly, if light and heat broke the plastic down into a fine powder, there is no research to show if it might act as a sponge for other pollutants. Oxo-degradable plastics may or may not be environmentally friendly by all these measures, and without further study, it’s too early to know which side of the industry is right.

The article also left out perhaps the most surprising recommendation of the government review: that the best way to dispose of an oxo-degradable plastic is to incinerate it.  If it goes up in flames, all other questions of degradability – bio- or otherwise – become moot, and the environmental impacts would be essentially the same as an ordinary plastic.

The Telegraph should be commended for bringing issues related to oxo-degradable plastic to readers’ attention, as this coverage will help inform consumers to make environmentally-friendly decisions when choosing products.