(Updated Aug.19; adds comment from EPI) British food store and retail chain Tesco has opted to revert to standard polyethylene carrier bags and stops use of bags containing an additive that can help plastics oxo-degrade over time. Tesco says its decision is based on data showing these biodegradable bags actually are not very environmentally sustainable. For Symphony Environmental Technologies Plc, a supplier of such additives, the move appears driven more by concerns of profitability and less over environmental worries. And EPI, another supplier of these additives and the company whose additives had been used in Tesco's shopping bags, says Tesco's reasoning—that the additives were weakening the bags' strength— doesn't hold water.
Tesco began offering it customer degradable plastic bags in late 2005, and last year gave away about 2 billion of them. Additives in the polyethylene used to make the bags helps them degrade into water, carbon dioxide and biomass in 18 months or so, depending on conditions. The bags can be re-used as well. But a number of recent studies have questioned the environmental friendliness of oxo-degradable plastics, among them England's National Non-Food Crops Center (NNFCC), which has posted papers of the negative impact of the oxo-degradable bags such as that these do not degrade in composting centers.
Symphony, which supplies the d2w additive for oxo-degradation of plastics, was not the supplier of the additives that had been used in the Tesco bags, thinks Tesco should have called it and asked for its additives. In a statement the supplier wrote, "These bags were made with additive supplied by one of our competitors, and they were weak because they were not suitably made. This has nothing to do with degradability. We are supplying bags made with our d2w degradable technology to supermarkets all over the world and we do not get complaints that they are unfit for purpose. We offered to make the bags for Tesco but there was no response.
"Similarly, we cannot see that recyclability has anything to do with it. Our d2w bags can be made with recyclate, and can themselves be recycled together with normal plastics during their useful life which, in the case of a shopping bag is normally 18 months...By contrast bio-based plastics cannot be recycled."
This last has been a sore point for Symphony and its competitors, who face competition from suppliers and processors of bio-based plastics such as polylactic acid (PLA) as both sides strive for approval from customers, consumers and legislators. Indeed, the European Bioplastics trade group published a position paper in which it distance itself from oxo-degradable plastics, claiming these did not function as promised, left potentially harmful residue and could encourage littering.
For EPI, Tesco's statement that it noticed bags were weaker than before is a half-truth. Tesco, claims EPI, has had its processor downgauge the thickness of the bags and has had it increase the use of talc fillers and recycled content in the recipe. EPI says those changes caused bags to weaken, not its OBP oxo-degradable additives.
Continued Symphony, "Campaigns to reduce the use of plastic bags, and to make them from recyclate, are all very well, but what is to happen to the bags and other plastic products which escape collection? They will lie or float around for decades in the environment if they are not degradable.
"We think that the real reason why Tesco have taken this action is to save money. This is a pity, because the on-cost is very small, and Tesco had set an example to supermarkets around the world by supplying their customers with degradable carrier- bags." Tesco now supplies shopping bags that have about 15% recycled plastics content in them.
As we reported earlier this week the European Union is considering a ban of thin plastic shopping bags for the entire EU, a move being strongly opposed by industry.