Do Biodegradable Plastics Really Work?

Dr. David Wiles, board member of EPI’s International Scientific Advisory Board (ISAB), responds to a common question posed many times in the media such as the article found here: http://motherjones.com/environment/2009/05/do-biodegradable-plastics-really-work

Do  Biodegradable  Plastics  Really  Work?

The correct answer is Certainly, YES.

Let’s see where Ramani went wrong!

In trying to answer the question “Just how long does it take for conventional plastics to break down?” Ramani should have noted that there are dozens of different kinds of plastics available commercially and there is no single answer to the question for all these  different materials. His answers to subsequent questions make it clear that he’s talking primarily about polyolefins. Frequently he includes irrelevant consideration of compostable products. What follows here is a correction of his misleading/incorrect statements that do not apply to the oxo-biodegradable polyolefins developed by EPI.

1^st Question ….the time for conventional plastics to break down.

Considering PE and PP, Ramani is wrong when he says that “conventional petroleum-based plastics never really go away.” In fact, they do break down into pieces too small to be seen with the naked eye when their molecules have oxidized, become water-wettable (polar) and have been reduced in size (e.g., molar mass< 5000). These molecular fragments are, however, biodegradable. Moreover, neither the oxidation nor the biodegradation ceases just because the plastic fragments become “too small to be seen with the naked eye.” The oxidation products of the polyolefins are biodegradable and all arable land is active microbiologically, as are landfills. Conventional polyolefins truly “go away” although the abiotic oxidation can take many years. EPI technology speeds up (by a factor of 100 or more) the oxidation of polyolefins and biodegradation follows relatively rapidly.

2^nd Question …broken down plastics are better than litter.

Oxo-biodegraded polyolefins are indeed better than litter. The visual pollution ceases to exist and the molecular fragments will biodegrade leaving no harmful residue. Ramani’s convoluted answer is irrelevant since oxo-biodegradable plastics cannot be part of the contamination of the oceans to which he refers.

3^rd Question …biodegradable plastics are indeed “neat.”

Ramani likes the concept of biodegradable plastics although, as we shall see in later answers, he is leading up to the incorrect assumption that the only “truly” biodegradable plastics are those that are in fact compostable. He would like people to accept that biodegradable really means compostable. This is completely wrong, as he is well aware. He “explains” that some companies are making conventional plastic that degrades quickly and then are “throwing around claims about biodegradability that are unproven…” Let the record show that oxo-biodegradable polyolefins produced using EPI technology have been proven repeatedly to degrade quickly and the degradation products biodegrade.

4^th Question  …biodegradable plastics break down in a landfill.

Ramani incorrectly says that “usually, nothing breaks down in a landfill.” He also refers to “this oxygen-free [landfill] environment” although there is irrefutable evidence in the scientific literature that aerobic biodegradation persists for months after landfill disposal of MSW. Specifically, it has been shown over and over again (in 3 different countries) that EPI’s oxo-biodegradable PE oxidizes in commercial landfills and that the oxidation products will biodegrade. After the landfill becomes anaerobic, EPI – PE no longer oxo-biodegrades; it does not undergo anaerobic biodegradation to produce methane although much of the organic material in MSW does. It is microbial activity that keeps the temperature ‘inside’ landfills so high.

5^th Question …how to avoid fake biodegradable plastics.

Ramani’s answer here is wrong again. He confuses biodegradable plastics with compostable plastics.      As noted above these are not the same thing. Most commodity plastics will, after use and disposal, either be recycled or end up in a landfill. Recycling of oxo-biodegradable polyolefins is a good thing; oxo-biodegradation in a landfill is a good thing. Compostable plastics, on the other hand, cannot be included in the conventional plastics recycling stream. Most plastics do not need to be compostable.

6^th Question …best way to get rid of biodegradable plastic.

Ramani is wrong again! Real biodegradable plastics should not be sent to a commercial composting facility even if you can find one nearby. Real biodegradable plastic should be used, re-used and finally collected for recycling. Yes, EPI – based PE is readily recyclable; compostable plastics must not be included in the normal recycling programs.

Readers, what are your comments or thoughts after reading the Mother Jones article and my response?