Degradable PE shopping bags a real threat to environment?

According to a recently completed study by a Berlin interest group, some kinds of degradable polyethylene (PE) shopping bags may be harmful to health, recycling, and the environment. The accusations by the International Biodegradable Polymers Association (IBAW) don''t cover all PE bags, just those using metal-based additives that are included to promote plastics breakdown during the waste process.

Such materials have been marketed since the 1980s. The group''s position paper looked at claims by additives producers that say their products allow PE bags to become oxo-degradable, biodegradable, or compostable. Harald Käb, IBAW chairman says none of the products studied meet European standard EN13432, which defines whether plastics packaging is biodegradable or can be composted.

Käb says these additives initiate decomposition and produce small, brittle matter but degradation remains slow-too slow to meet the criteria of the EU standard. Resulting PE dust accumulates, can become wind born, and affect plant and animal life by accumulating in feed and ground cover. Käb also says marine life suffer from such plastics residue.

Additives to initiate the decomposition such as cobalt, can be harmful since they are carcinogenic and in high dosages could affect worker health, he says. The IBAW criticizes that such bags containing metal-based additives are advertised to solve littering problems.

"Even if the bags are collected in plastics recovery schemes, the concept is hardly an innovative and favorable one. The additives destabilize plastics recyclates of mixed origin, leading to a reduced technical and economic value of [the] recycled plastics," he says. -Robert Colvin; [email protected]