Why ban plastic bags? Make them degradablePosted on March 6, 2012 by DrRossH in Plastic Waste News
Where do we start with such a marketing snow job done in that above article.
First for Annelisa, these bags Symphony talk about are not biodegradable. They are called Oxodegradable. They are degradable only, which means they fragment into little pieces the blow around the environment which is a worse problem as now we have small fragments of plastic getting into food chains, into the soil and waterways.
There are landfill biodegradable bags and they are made by adding a small amount of additive to the plastic media. This is a similar procedure to how the Symphony product is added in. The difference from there on is hugely beneficial however. Landfill biodegradable bags will not fragment and get into the environment, they will biodegrade in a landfill environment (which oxodegradable bags will not do). They can be recycled in main stream recycling to make new bags, which oxodegradable bags cannot do. They do not require oxygen or sunlight to work which oxodegradable plastics do. The list of benefits of landfill biodegradable plastics goes on. Causing plastic to fragment into little bits is not a cure for litter, it exacerbates it.
The claim of oxodegradable bags biodegrading is not supported by any testing with certified results. There is a reason for that. First the bag has to break down into little fragments. To do this is needs heat and some need sunlight. The heat that is used in the tests to cause the oxidation or breakdown is higher that the heat levels the bag would ever see loose in the environment. Then to go on and say these plastic fragments then biodegrade requires a scientific test to measure the CO2 given off. This is the problem, they can’t measure the CO2 given off by these little fragments. Instead they used a heat process on the plastic then mixed it with soil. Then they looked at a microscope of the plastic and saw it had been colonised by microbes and made the conclusion it was biodegrading. No actual test results cited. One review of their test method had this to say. ” ASTM D6954-04 states under ‘Scope‘ that “accelerated oxidation data must be obtained at temperatures and humidity ranges typical in that chosen application and disposal environment, for example in soil (20°C to 30°C), landfill (20°C to 25°C) and composting facilities (30°C to 65°C)”. It is not clear from the claim or the cited documents how thermal treatment at 70°C for 7 days complies with the standard, given that the soil temperature to 15-20cm (the oxygen rich portion) is usually that of air temperature.” It is also not clear from the report which of the referenced reports in ASTM D6954-04 is being addressed by the microscopic examination.
They are correct we would not have large pieces of plastic floating in the pacific garbage patch, had an oxodegradable additive been used in the plastic. What we are more likely to have then is a soup in the ocean full of tiny plastic fragments. Fish would be eating these constantly as they can’t separate the plastic bits out from the plankton. There is already I read 6 times as much plankton sized bits of plastic as there are plankton in the pacific garbage patch. Imagine what that would jump to if we made all the plastic fragment into tiny bits. We would have plastic laden fish, which in turn get eaten by birds and bigger fish and up the food chain all this plastic soup would go, claiming victims all along the way.
So we should be very careful when listening to great claims by manufacturers about their products as they are not telling us about their down sides at all.
As for plastic bags at the grocery stores. Look at the Tesco fiasco last year where they dumped Symphony products as the bags were failing in the store.
Plastic bags should be banned and people will just get used to taking their reusable bag after a few mishaps like Annelisa has experienced. One day we won’t even remember these disposable plastic bags thankfully. People of the future will look back and say what were you thinking back then?