'Degradable' plastic bags are no such thing, claim experts
The plastic bags sold in Israel as "degradable" are in practice no such thing, warn experts.
Ironically perhaps, just yesterday the ministerial legislative committee approved the bill proposed by Dov Khenin of Hadash to ban regular plastic bags and promote the use of degradable or cloth bags instead.
Concern for the planet has been prodding growing numbers of consumers to pay more for "biodegradable" plastic bags, sold in green packages bearing a picture of trees. The package claims that the bags are "ecological and protect the environment."
The snag is that because of how Israel handles its trash - burial - the bags do not in fact degrade, and cause no small degree of environmental damage, claim some experts.
Most of Israel's would-be degradable plastic bags sold by Sano and Hogla Kimberley Nikol. The bags are made by a production process called OXO Biodegradable. During the process, a chemical is added that breaks down the plastic molecules over time.
The manufacturers promise that the substance completely destroys the bag in 24 months, aided by light, oxygen, heat and humidity. This is where the rub lies.
At first light, oxygen and heat degrade the plastic into small bits. During the second stage, micro-organisms in the ground are supposed to finish the job, exactly as they would organic material."The main problem with this story is that when bags like that are buried in garbage dumps, where all Israeli garbage goes, there's no oxygen or light," explains Michal Eitan, former chief operating officer at Check Point Software Technologies and now an expert on sustainability in business.
The Knesset's research and information center also studied the subject and agrees. "The efficacy of degradable plastic is badly diminished if products made from that substance are buried in the ground and in dumps," writes the center.
But even if the "degradable" plastic bags were left in the open air, they wouldn't fully degrade, says Eitan, because they wouldn't reach the stage of degradation by micro-organisms.
During the production process, a substance is added to the plastic that makes it vulnerable to sunlight, says Gal Ostrovsky, an expert on trash and recycling at the Israel Union for Environmental Defense. "They think that will make the [plastic bags] disappear. But it doesn't meet the definitions of 'degradable bag,'" he says.
Eitan claims that everywhere the "degradable" plastic bags came into use, lawsuits ensued over truth in advertising. Manufacturers were forced to reword their claims on the packages, she says.
The companies that make the bags and chemical additive disagree. They have studies showing the bags can degrade up to a depth of three meters below ground level, they say.
Then there's NAPCOR, the North American organization for recycling plastic bottles. Its name stands for "The National Association for PET Container Resources," PET being a widely used plastic packaging material. NAPCOR recently called on food companies to eschew use of these degrading chemicals in packaging until their efficacy is proven.
One of NAPCOR's concerns, shared by many a green group in Israel and elsewhere, is that unless degradable and nondegradable plastics are handled separately, they could wind up being recycled together - creating plastic products that fall apart in sunlight and air.
Another potential hazard is that the substance in the plastic causing its degradation could become airborne and enter the food chain, with unknown effects.
The only 100% degradable bags are made of natural substances. But they are expensive, costing three to four times the price of your usual plastic baggie. And they aren't widely available in Israel.
To test whether a bag degrades, says Ostrovsky, one has to check whether it meets European standard 13432EN.
The bags made by Sano and Hogla-Kimberley using the OXO method do not meet that standard.
Ostrovsky is also a member of the standards board, whose function is to create an Israeli standard for degradable bags.
"The public doesn't know exactly what it's buying, so the standard will require the companies to divulge whether the bags degrade biologically, and how long it takes," says Anna Dotan of the Plastics Engineering department at the Shenkar College engineering and design school, who also sits on the standards board.
Dotan begs to note that the jury's still out on "degradable" plastic bags - there's no consensus. The bags currently being sold in Israel as "degradable" will degrade in two years under laboratory conditions, she says. But when they're buried with yesterday's sandwich and your old boot, and no sunlight and heat reach them, they don't degrade.
The bottom line, say the researchers, is that people should use less "disposable" bags, period.
Both Sano and Hogla-Kimberley dismiss the allegations about the danger to plastic products that may contain some of the chemical after recycling: The concentration would be too low, they say. Michal Bahat of Nikol's products department claims that the bags do degrade: "There's enough oxygen and heat, and there are studies showing so," she says.
Sano: "Degradable ecological bags have all the required approvals [attesting to] 100% degradation, even non-toxic degradation (such as methane), including degradation of the bags underground. The requirements of the European standard for OXO products have been defined and the standard is in the process of final approval. Sano's bags meet all the requirements."