Dear Friends--Yet another article that shows the use of "compostable" plastic bags to be of dubious value. Tom
>Date: Thu, 16 Aug 2007 10:14:05 -0700 >From: "Chura, Neil" <[EMAIL PROTECTED]> >To: "Fostering Sustainable Behavior Listserv" <[EMAIL PROTECTED]> >Subject: The Dirt on Compostable Plastic Bags? - from Clean Calgary > Association > >The article below has been copied from the Clean Calgary Association >newsletter. It presents some sobering thoughts for any that breathed a big >sigh of relief with the arrival of compostable plastic bags into the >retail landscape. If this research is sound -- and I'd like to hear what >other people think -- then reusable cloth bags for shopping are really the >no-brainer, sustainable solution. Furthermore, with 'sugar coating' on >corn-starch shopping bags quickly disappearing, it would seem that there >really is no sustainable way to throw things into the landfill. In short, >zero-waste is really the only policy option. > >Cheers, Neil > > > >Know your Shopping Bags > >Over the last year weve witnessed plastic bag bans in San Francisco and >Leaf Rapids Manitoba, the introduction of the $960 designer hand-wrought >silk shopping bag, and more recently, in an attempt to green their >operations, a trend towards degradable and compostable bags by retailers. >Here in Calgary Ive been handed compostableplastic bags at Mountain >Equipment Co-op, degradableplastic bags at Community Natural Foods, and if >thats not confusing enough, Planet Organic is now supplying customers with >oxo-biodegradableplastic bags. It now seems that the long-despised plastic >bag is facing some tough competition but how do these alternatives measure >up and what can a person do with them once theyve unloaded their precious >contents? > >Before getting into the details, simply put, compostableplastics are made >from farmed products like cornstarch and are broken down by >microorganisms. Degradableand oxo-biodegradableplastics are made from >fossil fuels and additives, breaking down when exposed to heat, moisture >and/or ultraviolet (UV) radiation. Because each of these bags has unique >qualities, they must be differentiated before deciding whether they should >be placed in the garbage, compost or recycling bin. > >According to the American Society for Testing and Materials (ASTM), an >international body that has established standards for compostable and >degradable plastics, compostable plastics are "capable of undergoing >biological decomposition in a compost site&, such that the plastic is not >visually distinguishable and breaks down to carbon dioxide, water, >inorganic compounds, and biomass&, [leaving] no toxic residue." >Compostable bags do not undergo this ideal transformation when placed in a >landfill, however. This is because modern-day landfills are largely void >of oxygen. When compostable items, including grass clippings, leaves, >fruit and vegetables, coffee grinds, newspapers, etc. enter a landfill, >methane gas is created. This is problematic because methane - a greenhouse >gas - is 20 times more effective at trapping heat than carbon dioxide. In >2003 alone, as a result of compostable materials, Calgarys landfills >emitted as much greenhouse gases as nearly 75,000 sport utility vehicles >(SUVs) driving for an entire year. Methane release from landfills will >only increase if consumers start adding compostable plastic bags to their >garbage. > >As for recycling, compostable plastics are not intended to be recycled and >when they enter the mix, they create all sorts of headaches for recyclers. >Plastics and compostable plastics have very different properties and >several local plastic recyclers have stated that mixing the two results in >serious product quality issues and therefore cannot be done. If consumers >are to truly make good use of their compostable bags, they must be composted. > >The other degradableplastic bags, including oxo-biodegradableplastics, are >simply fossil fuel-based plastics that have been modified with additives >so that they degrade faster. Large molecules are broken into smaller >molecules or fragments by moisture, heat or exposure to UV light and once >the fragments are small enough they will biodegrade. It should be noted >that there are no requirements for this to be done by naturally occurring >microorganisms, meaning that degradable plastics, as defined under the >ASTM standard, cannot be claimed to be compostable. They can, however, be >recycled at the various green recycling bins around Calgary and unlike >standard plastic bags that may hang onto their contents for hundreds of >years in a landfill, degradable and oxo-biodegradable bags are likely to >decay in as little as twenty four months. > >It's important to understand the difference between these bags and the >impact they can have on the environment. >Replacing normal plastic with degradable and compostable bags is not >without problems and this information should not deter citizens from >making the best shopping bag choice not using a bag at all! With 55 >million plastic bags going home with Canadians each and every week, >individuals can make a meaningful contribution to the problem by simply >loading up a reusable bag. If, however, you find yourself with one of the >alternatives, remember if it says compostable, compost it. If it doesnt, >do your part and recycle it. Tom Shelley 118 E. Court St. Ithaca, NY 14850 607 342-0864 [EMAIL PROTECTED] http://www.myspace.com/99319958 _______________________________________________ RSS, archives, subscription & listserv information for: [email protected] http://lists.mutualaid.org/mailman/listinfo/sustainabletompkins free hosting by http://www.mutualaid.org
