Africa, Environment, Headlines

ENVIRONMENT-SOUTH AFRICA: How Friendly is Biodegradable Plastic?

IPS Correspondent

CAPE TOWN, Jul 7 2009 (IPS) - Awareness of pollution and the amount of waste going into limited landfill space is encouraging the growing adoption of products with biodegradable plastic packaging. But environmentalists are challenging the claims made for these green products.

"Policymakers have tended to concentrate on waste which can be collected, and have encouraged people to reduce, re-use, and recycle, but in no country in the world will all the waste be collected, and some will always remain to disfigure the landscape," says Michael Stephens, deputy chair of Symphony Environmental Technologies, manufacturers of oxo-biodegradable plastic.

"This is particularly true of plastic, which can accumulate in the environment, polluting the land and the oceans for decades, and perhaps for hundreds of years. However, Symphony’s d2w oxo-biodegradable plastic will self-destruct if it gets into the open environment. Oxo-bio plastic is made from a by-product of oil refining which used to be wasted, so nobody is extracting or importing extra oil to make it."

Biodegradable plastic contains chemical additives which its promoters say allow it to break down after disposal, instead of remaining in the environment. There are two main kinds of this plastic, hydro-biodegradable and oxo-biodegradable.

Last year, Symphony clinched a deal to supply oxo-biodegradable plastic packaging to Albany Bakeries, a subsidiary of South African food giant Tiger Brands. Symphony says the packaging will degrade in less than six months, leaving behind no fragments or harmful residues.

Critics like Bruno de Wilde, lab manager at Organic Waste Systems, a Belgian consulting company that tests biodegradability of consumer products, are not convinced.

"To be beneficial to the environment, a polymer (plastic) should disappear completely. In biodegradation, this means a natural conversion to CO2 and water," explained de Wilde. He Wilde warns that the minuscule plastic fragments a piece of oxo-bio plastic degrades into may enter the food chain and pose health risks.

Stephens rejects this challenge. "Symphony’s d2w plastic degrades by a two-stage process. The first phase is abiotic oxidation in which the d2w formulation breaks the molecular chains within the polymer. When the molecular weight has reduced to 40,000 Daltons or less, the material is no longer a plastic, but a material which can be bio-assimilated by naturally-occurring micro-organisms in the same way as nature’s wastes. At the end of the process there is only water, CO2, biomass and trace-elements."

Exactly long it will take for a given piece of oxo-biodegradable plastic to fully break down is impossible to say, because this depends on the conditions under which it is disposed of: temperature, or exposure to sunlight, for example, will affect the speed of breakdown. But, says Stephens, as long as oxygen is present, independent tests show that d2w plastic will degrade more quickly than natural materials like leaves or straw – and far more quickly than ordinary plastics.


A major dispute between critics and promoters of oxo-bio plastic is what is the appropriate test of this claim. Symphony says its product has been independently tested against British and European guidelines for food and soil safety, as well as biodegradability. Critics however point out that it has not been certified in line with widely-used EU standard EN 13432 for "packaging recoverable through composting and biodegradation" (which closely resembles a U.S. standard, ASTM-6400).

South Africa lacks its own certification system for biodegradable products and Muna Lakhani, national coordinator of Durban-based Institute for Zero Waste in Africa, says this is a weakness. "[The government is] far too quick to allow companies to release products without any sort of oversight," he says. "The number of new chemical products released every year, with zero requirements for environmental, social and health impact assessment, is of great concern."

The Oxo-biodegradable Plastics Association, an industry grouping, doesn't believe EN 13432 – particularly the requirement of compostability – is appropriate to their products, and has pushed for a review.

"Composting of organic waste makes sense, but compostable plastic for shopping bags, food packaging, shrink-wrap etc. does not," says Stephens. "It is up to 400 percent more expensive than ordinary plastic; it is thicker and heavier and requires more trucks to transport it; it uses scarce land and water resources to produce the raw material, and substantial amounts of hydro-carbons are burned and CO2 emitted, by the tractors, trucks, and other machines employed."


A different challenge to the environmental credentials of oxo-biodegradable plastics is that they can only be safely and successfully recycled if they are captured into the recycling stream within a few days of use.

"In waste collection you don't know how old plastics are, so it is likely that in the mechanical sorting process, oxo-biodegradable plastics could end up in the manufacture of other products and continue to degrade," says David Hughes, executive director of the Plastics Federation of South Africa, who has convinced industry heavyweights like Coca-Cola and Woolworths to steer clear of oxo-biodegradable plastic.

"Recycling companies won't want to take products made from oxo-biodegradable plastics. This will disrupt the recycling industry which is creating jobs in South Africa," he added.

Not so, says Stephens, any concerns over recycling should be directed at starch-based or hydro-biodegradable plastics.

"There is no issue at all (with oxo-biodegradable plastic) unless the recyclate is intended for long-life film products such as building films. These are usually made from virgin polymer, or from recyclate whose provenance is known. Long-life films should not be made from mixed rubbish whose provenance is unknown."

The entry of any new product generates debate and it is still too early to assess the impact of oxo-biodegradable plastics on the environment and economy of South Africa.

Zero Waste's Lakhani urges caution. "Legislation tends to kick in only when harm is done, so there is no application of the precautionary principle," says Lakhani.

He calls for environmental activists to lobby the national Department of Environmental Affairs and Tourism as well as the health department to ensure South Africa's environmental regulations match international standards.

"I would like to see a body established that would aim to phase out unsustainable and unsafe products and processes, including many plastics, and be tasked with replacing these with safe, local, renewable and job-creating alternatives," added Lakhani.

*The original of this story, moved Apr. 15, failed to accurately present the views of the manufacturers of d2w.

Republish | | Print |