Look before you leap or look before you push us

It must have seemed like a good idea at the time. Having been fiercely criticised for its handing out of sing use plastic bags the international supermarket chain Tesco came up with a bright idea; they would make their familiar free plastic bags biodegradable.

Simple. They would add small amounts of metal to the plastic which they use to make up the bags. The bags would then break down in the presence of oxygen and daylight and hooray, Tesco would save the planet. The bags (known as oxo biodegradable bags) went into product more than eighteen months ago and Tesco virtuously handed out them at the rate of two billion a year.

Good intentions are not enough to save the environment. Things are rather complex and you cannot rely on a bright idea without thinking it through properly and doing the research otherwise you run the risk of your bright idea causing more harm than it mends. We do rush into things, without thinking them through; that is why we have wind turbines that generate electricity intermittently, over subsidised photovoltaic panels and low energy light bulbs that may end up creating atmospheric mercury without creating that much light.

Having produced their biodegradable bags with a flourish of publicity, Tesco left it to others to study the real environmental impact of their bags. In this case DEFRA (theUK’s Department of Environment, Food and Rural Affairs) organised the study appointingLoughboroughUniversityto study and report on them.

You can read the report at http://wales.gov.uk/docs/desh/publications/100602wasteoxydegradableen.pdf . It concludes that the bags do break down more quickly provided they are exposed to ultra violet light and oxygen, but the breakdown does not take eighteen months but somewhere between two and five years before the bags degrade to small fragments. However, they only degrade to small fragments, and do not degrade into substances that can be mixed with compost; in fact mixing the bags with compost (that you might be tempted to do with a biodegradable bag) will adversely affect the quality of the compost.

The researchers are not sure what the environmental effect of plastic fragments in the soil will be on animals that eat it. There is no evidence that it is harmful, but no evidence that it is not harmful. Further the bags are difficult to recycle with under plastics. This makes the bags unlikely to be recycled or if mixed with other normal plastic waste makes the recycling harder.

The metal additive made the bags weaker and made them unsuitable for being reused; you would more likely throw them away where they would not degrade because when the bags are used in landfill (as most of them are) they will not degrade at all; there is no ultraviolet light underground.

Of their decision to take the biodegradable oxo biodegradable plastic bags out of use Tesco said

“We took the decision to remove the biodegradable additive because we believed it contributed towards bags becoming weaker and to help better promote their re-use and recycling at end-of-life. This decision was underpinned by a detailed review of the science to help us understand the full life-cycle environmental impacts of our carrier bags.”

It is a shame that Tesco did not themselves commission and pay for the research before they put this type of bag into the environment. They did not look before they leapt. You are supposed to to that so that you know the consequences of your action but as with so many corporate decisions the consequences of leaping do not  affect the company as much as they affect the environment. Looking before they leap is costly for companies like Tesco whose actions have great and adverse effect upon the environment. The problem is that the consequences of their actions, their leap, affect us more than them. It is not a case of looking before they leap but looking before they push us.

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