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Plastic problem all wrapped up? The National, 10.12.2008

New biodegradable shopping bags that disintegrate after a few years are an improvement over the old kind that can survive for centuries, but environmentalists warn that they must be considered only a part of the solution to the problem of pollution. Jo Wadham reports.

Strong, durable, waterproof and flexible, plastic is pretty fantastic. Unfortunately, it has a major drawback: it takes between 400 and 500 years to decompose, and 80 per cent of plastic packaging is used once and then discarded. Plastic, whilst useful, has become a scourge of environmental and animal welfare advocates across the world. But what if plastic could be made to degrade more quickly? This is what a UK company, Symphony Environmental Technologies plc, claims to have done with the creation of a new additive to plastic, d2w.

D2w is added to the raw polypropylene or polyethylene pellets in the plastic production process to create end products with a defined lifespan. This means that they have a period of usability before the plastic weakens, fragments and ultimately disappears. For a plastic shopping bag this may be between nine months and one year. For agricultural film, the lifespan can be preset according to the farmer’s requirements. These plastics are called ‘oxo-biodegradable’ because they require oxygen to break down into carbon dioxide, water and some biomass.

Plastic is made up of carbon and hydrogen atoms bound together in long, entangled chains that give it its strength. While d2w’s exact chemical makeup is guarded with the same secrecy as Coca Cola’s recipe, it consists of metal salts that act as catalysts for the oxidation process by weakening carbon bonds and reducing the molecular mass of the material to the point at which oxidation can occur. Oxygen atoms then bond with the hydrogen to form water and with the carbon to make carbon dioxide. Micro-organisms also help to consume the carbon and hydrogen.

Symphony Environmental, through its UAE-based agent, Eco Polymers, hopes to supply d2w across the Middle East. They already supply nearly all the large plastic producing factories. These factories are then able to provide their clients with degradable plastic bags. The Abu Dhabi Cooperative and Dubai Municipality are using them already, and the LuLu hypermarket chain has just made the decision to use d2w in its bags.

Peter Lonsdale, the retail operations manager for LuLu in Abu Dhabi, describes the decision to use oxo-biodegradable plastic bags as “part of our corporate and social responsibility. We can still offer carrier bags and help the environment at the same time”. He adds that LuLu is considering bringing in a “bag for almost life” containing d2w, which would last for three years. At the end of the bag’s life the customer could exchange it for a new one.

“We don’t want to stop at carrier bags either. We will look at packaging: milk cartons, plastic packaging and cling film. This is the start of a long journey for us. More education is needed in the UAE regarding the environment. This is part of our responsibility as well: to reuse, and use less, carrier bags.”

For the plastics manufacturers, the only additional cost is d2w itself. And Symphony Environmental’s ambitions are not confined to the Middle East. As Winston Pryce, general manager of Eco Polymers, explains, “our aim is to get d2w into every kilo of plastic that is made”.

While there are many who have called for a total ban on the production of plastic, few have offered a sustainable alternative. Mr Pryce is clear that “there is no economic or environmental advantage in paper.” He suggests that we look at the environmental impact of producing paper and jute bags from beginning to end because “a paper mill uses huge quantities of water, huge quantities of electricity, huge quantities of chemicals”. Furthermore, “a paper bag of equivalent strength [to plastic] will be at least 10 times as thick and heavy, so the logistic cost will be higher – more ships, more lorries”. As for jute, he argues that using scarce arable land to produce jute rather than food in times of food scarcity is not a sensible allocation of resources. In addition, both paper and jute produce methane when they degrade, which is 20 times more powerful as a greenhouse gas than carbon dioxide.

Plastic, on the other hand, can be made from naphtha, a by-product of oil production. Any naphtha not used to make polyolefins is flared off as waste at the refinery. As Mr Pryce says it isn’t really very “green” to import jute to make bags when plastic can make use of a material produced in abundance in this region.

However, plastic made with d2w is not the perfect solution. While the plastic degrades, it will fragment. Above ground, where the plastic can be oxidised, this process may take just weeks. At a landfill, it could be up to two years. As additional refuse is placed on top of a d2w bag, the oxygen supply gets cut off, possibly at a stage when the bag is only partially degraded into fragments. Some scientists are concerned about the potential danger to the environment and animal life of such plastic fragments persisting in the environment, and some claim that even microscopic fragments of plastic in the sea pose a threat to marine life.

Producers of biodegradable bags made from maize or wheat starch argue that oxo-biodegradable bags should not be called biodegradable, as they do not compost as quickly as their products. The Oxo-biodegradable Plastics Association (‘OPA’), the chair of which is Symphony Environmental Technologies’ chief scientist, agrees that it is unacceptable to have plastic fragments in the soil. However, it argues that by this stage the oxo-biodegradable bag no longer has the properties of plastic and will be “bio-assimilated” meaning that it will become part of the environment just “ straw, leaves and twigs.” Mr Pryce adds that a fragmented bag will take up less room in a landfill and will have spilt any organic matter that may have been placed inside it. Significantly, the OPA maintains “oxo-biodegradability is not a disposal option” but aims mainly to address the plastic litter problem. “The main benefit of oxo-biodegradable [bags] is not for plastic waste that gets into landfill, but for plastic waste which gets into the environment, where it will accumulate for many decades”. Other degradable plastics, such as those with a  starch base, have their own drawbacks. They cannot be recycled like their oxo-biodegradable counterparts, and when they degrade they emit methane.

D2w could be seen as encouraging a shift in attitude from “reduce, reuse, recycle” to “use it once or twice and watch it disappear”. Oxo-biodegradable bags can be recycled with other plastics, but the fact that they will degrade could absolve consumers of their duty to dispose of plastic responsibly. If the bags are not recycled and allowed to degrade, there will be associated carbon dioxide emissions.

Of course, degradable carrier bags can be re-used by the consumer, but only for a limited period. Symphony can, if there is the demand for it, produce tougher, washable, fabric-like bags, with a d2w-controlled lifespan of five years, such as those contemplated by LuLu Hypermarkets. This would encourage a sensible approach by shoppers towards consumption and disposal of plastic. The demand needs to be there first: shops need to believe this is what their customers want.

Bags with a limited life span are, according to the OPA, “a low cost insurance against the accumulation of plastic waste in the environment”. The Emirates Environmental Group (EEG), a non-government organisation, while welcoming the new technology of oxo-biodegradable bags, emphasises that this does not release individuals from their responsibility to the environment. Furthermore, as Habiba Al Marashi, chairperson of the EEG states, “the government should come up with regulations to limit the use of plastic bags while encouraging the wider availability of re-usable alternatives like jute bags, cloth shopping bags, among others. The degradable plastic should only be one of the alternatives”.

According to Mr Pryce, however, d2w is “the solution to the plastic pollution problem… There is no viable alternative to plastic”. But its real value may be in its use in conjunction with a nationwide education policy about responsible disposal and a commitment to recycling. It is an insurance policy, yes, but if we really want to protect the environment, we should do as the EEG advises: “We should reduce our waste by reducing our consumption and that is by balancing our needs and wants. We should pick the items that we could re-use and recycle from the things that we want to throw away. We do not need high technology to do this, just our good old fashioned common sense.”

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