composting

Just like regular plastic, oxo-degradable plastic is made from oil or natural gas by-products, and according to the Oxo-Biodegradable Plastics Association (OBPA), degradation is possible by adding a chemical substance that decreases the material’s molecular weight over a given time period.

This additive process helps to speed up oxidation of the plastic, which then breaks down as long as the necessary elements of oxygen and microorganisms are available, such as air, soil, landfill, compost, and litter (Ecosafeplastics.com).

Proponents of oxo-degradable plastics claim various science-backed advantages, such as recycling safe and food safe, and also state that the oxo-plastics will biodegrade. However, this is where the debate gets a bit blurry because there is as of yet no one standard for the exact definition of “biodegradability.” According to a recent article from the European Plastics News, the ISO 17088 for example “requires that total biodegradation must be achieved within six months.” For oxo-degradable plastics biodegradation can be a whole lot longer – beyond twelve months.

Also, the Biodegradable Products Institute (BPI) says they have not yet seen any science backed “biodegradable” plastics that will break down completely in landfills within twelve months and leave no residue as per consumers’ expectations.

According to the US Federal Trade Commission (FTC) Green Guide, a product or package qualifies as biodegradable if it “completely breaks down and returns to nature, decomposing into elements found in nature within a reasonably short period of time after customary disposal.”

Oxo-degradable plastics will leave residues behind in the environment after degradation. Even though these microscopic pellets are not toxic and will not emit methane or nitrous oxide (OBPA 2010), they still remain in the environment and thus, the “biodegradability” argument continues.  

One major argument for oxo-degradable plastic is that as long as oil and gas extraction continues for energy consumption, it makes sense to use the associated by-product. Some sources question the use of limited land and water resources for example to produce bio-plastics such as PLA (corn plastic) which requires special industrial composting at 140 degrees. On the other hand, our dependence on non-renewable resources has to shift sooner rather than later so we would be wise to incorporate the available alternatives and help to optimize them.

In addition to the increasing use of PLA, there are agricultural fiber based products available on the market that are made from renewable resources, such as palm, bamboo, bulrush, and bagasse. These products are 100 percent compostable in the backyard compost and once broken down, make a healthy contribution to the soil as humus.

There are concerns that the majority of consumers will still toss compostable plastic packaging into their regular recycling or waste collection bins, especially since the infrastructure for curb side pickup of compost is not yet readily available in many municipalities. However, consumer awareness and responsibility is on the rise and an increasing number of individuals compost and sort their recyclables.

Statistics Canada says that in 2006, 30% of Canadians did compost their kitchen waste through a curb side program. In addition, many municipalities are starting to add compost to their curb-side pickup. Vancouver, my hometown, for example, has just announced their commitment to start a curb side compost program on Earth Day, April 22, 2010. Stay tuned to this blog for a discussion on Vancouver’s new composting initiative.

More links of interest:

Oxo-biodegradable Plastics Association

Symphony Environmental

Ecosafe

The Packer: Debate arises on sustainable packaging

PlasticsNews.com: Bioplastics industry joins oxo-degradable debate

Edie.net: ‘Degradable’ plastic not so environmentally fantastic, study reveals

Biodegradable polymers market to grow at 13% through 2014

The Truth About Bioplastics