Plastic bags - Environmental Audit Committee Contents

3  Disposal and recycling of bags

50. Currently, over 8 billion carrier bags are used in England each year (para 4), and only a very small proportion are recycled, with most going to landfill or incineration.[113] However, plastic bags are a small proportion of waste overall, making up less than 1% of the 28 million tonnes of household waste a year. In contrast, food waste is 7 million tonnes (25%) and packaging 5 million tonnes (18%).[114] WRAP conclude "Given the low tonnage and the low degradation rate, the (non-litter) environmental impacts of actions related to plastic carrier bags are likely to be small, when compared to some other areas of waste and resource management (such as food waste prevention)."[115]

Proposed exemption for biodegradable bags

51. The Government has proposed an exemption for biodegradable bags, which would involve "ambitious standards".[116] It is "looking for UK industry to develop biodegradable plastic carrier bags that have low environmental impacts while still being useful to consumers".[117] Defra has set out that:

In an ideal world every single-use carrier that we use would have a number of functions and characteristics:

  • It would break down in all environments (marine, terrestrial, composting plants and AD plants) at the end of its service life and at a rate of degradation that offsets the rate of accumulation.
  • It would perform its function as a carrier bag well.
  • When it breaks down it would degrade quickly into demonstrably harmless products.[118]

Based on current evidence, Defra believe that there is no bag that meets these requirements. The Minister told us:

    At the moment I think it would be fair to say that I cannot see a product on the market that would meet the aspiration that we would have for that exemption. So I think this is something that we would see coming forward. We have made provision for that to happen, but we don't see a product out there that meets those criteria.[119]

52. Research by Loughborough University for Defra in 2010 concluded that there is currently no agreed standard for biodegradability:[120]

    The term biodegradable does not specify the extent, time-scale or conditions under which biodegradation has taken place. Compostable is more precisely defined. According to the European standard on compostable packaging materials, EN13432, a biodegradation level of at least 90% must be achieved in less than six months for a plastic to be described as compostable.[121]

There are however two main types of bag described in differing contexts as 'biodegradable':

i)  'Bioplastic': often made from corn-starch, and often blended with conventional plastics.

ii)  'Oxo-degradable plastic': largely made from naphtha, but with additives (usually metal salts) that, when exposed to ultra-violet light or dry heat and mechanical stress, break the plastic into small particles which may then be further degraded by micro-organisms.[122]

53. We received a range of evidence relating to the proposed biodegradability exemption, which showed often opposing views about the extent to which particular materials might be safely recycled and about potential harm in the natural environment. The Oxo-biodegradable Plastics Association maintained that their product would meet the criteria for an 'ideal bag': "fit for purpose, can be reused, recycled, will safely degrade and biodegrade if not collected, will not generate methane in the landfill and will cost little or no more than the ordinary plastic bag."[123] However, we received evidence from recyclers (paras 55-58) and an expert in how plastics degrade in the natural environment (paras 59-62) that contradicted that view.

54. Defra state that "standards are yet to be developed"[124] for the bag exemption. Barry Turner of PAFA described as "strange ... that this exemption is being proposed without us knowing quite what type of material they have in mind".[125] David Newman of Polythene Industries told us that the exemption for biodegradable bags "came completely out of the blue. It was a complete surprise".[126] Jessica Baker, of Chase Plastics and the British Plastics Federation Recycling Working Group told us that recycling groups only met with Government once before the policy was announced:

    Obviously we were quite surprised that, a week later, the carrier bag tax was announced and also the exemption for biodegradable was announced. I think we found that quite intriguing, because obviously Defra had given us the impression that it was the start of the debate, whereas, obviously, we felt then that, actually, decisions had probably already been taken. Although we did try and engage, up to that point we felt that we had been ignored.[127]

Professor Richard Thompson, a Marine Biologist, told us:

    I have acted as an adviser to Defra and the EU for a number of years. ... I was curious to understand the motivation behind the exemption. It was the biggest surprise of all within the proposals.[128]

However, Michael Stephen of Oxo-biodegradable Plastics Association said that they had had more meetings with Defra:

    We did have some meetings with officials at Defra—one meeting before and one meeting after the round table that Jessica Baker referred to. I, too, was rather surprised at how quickly the policy came out after the round table.[129]

The Defra Secretary of State, Owen Patterson, told the Environment, Food and Rural Affairs Committee in October that he took some responsibility for the proposed exemption:

    I am also very taken by the idea of a genuinely biodegradable bag ... You can partly blame me for this; I was really hoping that if we scoured the world we would find this technology.[130]

    The policy around the exemption for biodegradable bags appears rushed and taken before reviewing existing evidence or considering the concerns of all stakeholders.

55. We heard evidence about the best 'end of life' options for plastic bags, and also how different bags perform in the natural environment. It is clear from analysis done by the Environment Agency that different bag types require different processes at disposal (Figure 3).
Figure 3: End-of-life options for different bag types
Type of carrier bag Landfill Incineration Mechanical recycling Composting
Thin single-use High-density polyethylene (HDPE) plastic bag
HDPE bag

with a prodegradant additive ('Oxo-biodegradable')

Starch bag
Paper bag
Low-density polyethylene (LDPE) bag—thin bag for life
Non-woven PP bag-Thicker bag for life
Cotton bag

Source Environment Agency, 'Life cycle assessment of supermarket carrier bags: a review of the bags available in 2006' Table 3.2

56. We received extensive evidence from organisations involved in recycling plastics about the potential impact of dealing with biodegradable plastic bags. Recyclers were concerned that increasing the use of biodegradable plastics would threaten the viability of the UK recycling industry. Regain Polymers told us:

    The danger that biodegradable plastic presents to existing markets is simple. Once it becomes recognised that degradable plastic is routinely present in the UK plastic waste stream, confidence in recycled plastic will evaporate and not only will we fail to find new markets for the plastics we so ardently wish to recycle but those markets that already exist will themselves disappear. Far from biodegradable plastic bags being given an exemption to the proposed carrier bag tax, the use of any biodegradable plastics should be discouraged.[131]

Similarly, British Polythene Industries stated that they were:

    totally opposed to any exemptions for biodegradable bags, this would be environmental madness. Far from benefiting the environment, any exemption would inevitably lead to an increase in the use of carrier bags containing a degradable additive, these bags would—after use—enter and contaminate the plastic films waste stream. This contamination would cause huge damage to the UK plastic films recycling industry and inevitably lead to a reduction in the amount of waste plastic films recycled in the UK.[132]

Industry Council for Research on Packaging and the Environment told us that "the proposed exemption for biodegradable bags will result in the closure of UK plastics reprocessing with consequent job losses."[133]

57. Recyclers told us that they are concerned about two issues. First, that oxo-biodegradable materials would contaminate the waste stream because the additives that cause the plastic to degrade will remain in recycled products and lower the quality and durability of their products. Jessica Baker of Chase Plastics told us that recyclers "cannot have degradability built into long-life products, because it is just too dangerous".[134] She stated "It will not take long, if there is any doubt—even a shred of doubt—about the ability of our reprocessed products to remain stable, before the market disappears."[135] Oxo-biodegradable Plastics Association referred to a South African study that concluded that oxo-biodegradable plastic could be recycled without affecting the performance of the recycled plastic,[136] but we also received other evidence which reached the opposite conclusion.[137] Defra acknowledged that there are differing views on whether oxo-degradable products can be safely recycled.[138]

58. The second concern was that starch-based 'bioplastic' bags would damage recycling machines. Mike Baxter, of British Polythene Industries,[139] told us that "if starch-based products get into our recycling machines they will stop. LDPE [Low-density polyethylene] recycles at 200°C; starch is at a 150°C. We know, because every so often it gets in."[140]

59. UK recycling of household plastic film, including thin-gauge carrier bags, is still in its infancy. Over recent years, many major supermarkets have introduced collection points at the front of stores for plastic film and used carrier bags: an estimated 60% of UK stores now have these facilities. The collected plastic film (including bags) is baled in the UK, then most is exported to China for reprocessing.[141] Plasrecycle has recently built the first plant in the UK to reprocess carrier bags into a clean plastic granulate for reuse as new bags or black sacks. They believed that the promotion of degradable bags through the proposed exemption would be a "very bad idea since such bags, both bio-degradable and oxo-degradable cannot be separated from conventional non-degradable bags, so the whole stream will go to disposal rather than recycling".[142] Defra, who have commissioned research in this area, believed that:

    the solutions to these issues raised by recyclers lie mainly in the fields of improved detection and separation technology, e.g. the use of physical indicators such as colours or fluorescence, or better control of materials aid physical separation.[143]

Jessica Baker told us, however, that that she had asked a sorting machine manufacturer whether their infrared technology would be able to separate out oxo-degradable from conventional plastics:

    The answer was no. They could separate out starch, but obviously it is on a throw-out basis. So you either keep the starch and throw away all the plastic, or you keep the plastic and throw away the starch. It is not economically viable and it is not practical.[144]

    It appears to us that Defra is trying to use innovation to justify a rushed and flawed policy proposal to allow an exemption for biodegradable bags.

60. We heard that currently the only accepted standard for biodegradability is compostability (paragraph 51), but bags meeting that standard will not degrade as quickly in the natural environment as in specialist composting plants. Waitrose told us that "biodegradable bags (paper/natural materials) are not designed to degrade in anaerobic landfill conditions and could release methane under such conditions",[145] contributing to climate change. Professor Thompson told us:

    to call something biodegradable ... we are talking about it degrading in industrial composting at 50° C, with specific conditions of pH and humidity after it has been pre-shredded ... Material that at the moment is called biodegradable will not biodegrade in the sense that I imagine most members of the public would expect it to, which is harmlessly and quickly in the natural environment. It is going to do so in a commercial composter.[146]

61. Professor Thompson has examined how quickly plastic bags degrade in the marine environment. He found that compostable plastic disappeared after 16-24 weeks, but approximately 98% of other plastics (including oxo-biodegradable plastics) remained after 40 weeks, in part due to a lack of light reaching the bags under water.[147] Oxo-biodegradable Plastics Association pointed to other research that showed that oxo-biodegradable bags can degrade more quickly in laboratory tests.[148] We also heard that as the degradability rate of oxo-biodegradable bags is influenced by heat and light, they are likely to take longer to degrade in the UK than in warmer climates.[149]

62. The Irish Government considered that "biodegradable bags still take a considerable time to degrade and while their use may be preferable in a final treatment situation, such bags will continue to form a visible nuisance where discarded as litter".[150] Waitrose told us:

    The only benefit of a biodegradable bag therefore, is with regards to litter. However, existing types of bio (plastic) bags still take years to decompose. We need to be changing behaviour, not condoning the discarding of bags into the environment with the hope they will break down before they cause damage to marine life or unsightly litter.[151]

63. Plastic bags can cause harm to wildlife, particularly in the marine environment, and it is not clear that biodegradable bags significantly reduce that harm. The Marine Conservation Society highlighted a study of Green and Loggerhead Turtles which showed all types of bags degrading in their intestines insufficiently slowly to reduce morbidity.[152] We also received evidence, notably from Professor Thompson, indicating that even small particles of degrading plastic may present significant marine health risks.[153] Defra told us "Marine microplastics have been shown to absorb pollutants from the marine environment and are sometimes ingested by marine organisms. This is a cause for concern although at the moment we are not able to assess this harm."[154] The Defra Secretary of State told the Environment, Food and Rural Affairs Committee that "current [plastic bag] technologies ... in the marine environment would lead to real damage".[155]

64. The Government should remove the proposed exemption for biodegradable bags. It presents risks to recyclers and might cause as much harm to the natural environment and wildlife as new or recycled bags.

The need for a clear, consistent and coherent approach to waste

65. Axion Recycling suggested that waste management systems should not mix biodegradable materials with those that do not degrade.[156] David Newman explained how Italy had chosen to prioritise compostable bags, in order to support a food waste collection and composting system:

    We decided in Italy that the most important element of our waste strategy was the organic waste stream. The organic waste stream is 30% to 40% of our waste stream. It is today 40% of all our recycling in Italy.

    Therefore, it was critical to us that this waste stream is as uncontaminated as possible. That is why the perfect plastic bag for us in our country is a compostable plastic bag, because we can then use that to collect our organic waste in our households and send it to composting and to anaerobic digestion, therefore decontaminating the organic waste stream. That is the answer from the experience we come from. That is a strategic vision of the whole waste system that we have in [Italy].[157]

Jessica Baker noted, however, that such an approach would not currently be appropriate in the UK:

    Italy's situation is entirely different from that of this country. Our whole waste management legislation for the past 15 years has not been geared up to twice-a-week collections of food waste in a compostable bag. ... We have twice-weekly collections. The majority is now in a commingled collection. Unfortunately, that would mean that any compostable bag that was handed out in a supermarket would be a general-purpose bag. It would end up in the commingled waste stream and therefore would contaminate the whole of the domestic plastic household waste stream, and would not be able to be reprocessed.[158]

66. As Local Councils are responsible for waste disposal, it would be difficult to introduce a national policy that fits with every local authority's approach. The Co-op have trialled the sale of compostable bags for people to use to carry shopping home but then reuse for local authority food waste collection and home composting, but the pilots are restricted to local authority areas with a compatible waste strategy:

    As additional local authorities introduce food waste collection, low-cost accessible provision of caddy-liners in schemes such as this will only serve to improve resident engagement while minimising increased burdens on local authority budgets. The fact that we only sell the bags in areas where the local authority will accept them means that management of their suitability for anaerobic digestion is built in.[159]

A 5p carrier bag charge would have little impact on these schemes. Compostable bags are expensive to produce and currently retail at a cost price of 6p, which is cheaper than the cost of buying a roll of bags for composting. As the price of these bags is higher than 5p an exemption from the charge is unnecessary.[160]

67. There is a need for the Government to take a long-term approach to support the investment needed to meet recycling targets and ensure the financial sustainability of the sector. Jessica Baker of Chase Plastics told us how important recycling is for meeting the Government's "ambitious recycling targets for plastic", stating that recycling plastic bags "is going to be a means by which we could meet the new targets". The first plant in the UK to reprocess carrier bags and other post-consumer films back into plastic granulate for reuse in new bags has only recently opened, partly publicly-funded.

68. Defra's proposed exemption for biodegradable bags is risky and unnecessary. The decision to exempt biodegradable bags was rushed and taken without considering its coherence with wider strategies for reducing and managing waste, and the exemption could also undermine the reduction in bag use from the 5p charge. It is important that the Government gets the proposals for the carrier bag charge right, as it is one of the simplest and most effective ways of reducing resource use and helping people act in a way that has wider environmental benefits. The Government's waste management strategy needs to be clear, consistent and easy to understand in order to secure reduced carbon emissions, improved rates of recycling and avoid contamination of waste disposal streams. Gains in other areas could be far more important than can be generated by bags alone. We will return to these wider issues on waste in a subsequent inquiry.

113   Environment Agency, 'Life cycle assessment of supermarket carrier bags: a review of the bags available in 2006' Report SC030148 Back

114   WRAP (BAG 031), para 6 Back

115   WRAP (BAG 031), para 5 Back

116   Defra, Single-Use Plastic Bag Charge for England: Call for Evidence, November 2013,para 45 Back

117   Defra, Single-Use Plastic Bag Charge for England: Call for Evidence, November 2013,para 40 Back

118   Biodegradable Plastic Carrier Bags Solutions through Innovation' Defra research call Back

119   Q68 Back

120   The process where the material breaks down and is colonised and metabolised by microbes Back

121   Loughborough University (2010) EV0422 'Assessing the Environmental Impacts of Oxo-degradable Plastics Across Their Life Cycle' p1 Back

122   Defra Q and A Back

123   Q108 Back

124   Defra (BAG 032), para 22 Back

125   Q47 Back

126   Q88 [Mike Baxter] Back

127   Q87 [Jessica Baker] Back

128   Q89 [Professor Thompson] Back

129   Q90 Back

130   Oral evidence taken before the Environment, Food and Rural Affairs Committee on 29 October 2013, Departmental Annual Report 2012-13 HC741 Departmental Annual Report Q105 Back

131   Regain polymers (BAG 002, paras 4-5: Back

132   British Polythene Industries (BAG 007)  Back

133   INCPEN (BAG 008) Back

134   Q145 Back

135   Q103 Back

136   Oxo-biodegradable Plastics Association (BAG 026), para 33; Roediger report (2012) Back

137   European Plastics Converters (EUPC) (BAG 006); OPA disagree with this- Oxo-biodegradable Plastics Association (BAG 026), para 34 Back

138   Defra Q and A  Back

139   BPI is "the largest manufacturer/recycler of polythene film and bags in Europe"-Q87 Back

140   Q105 Back

141   WRAP (BAG 031), para 24 Back

142   Plasrecycle (BAG 003) Back

143   Biodegradable Plastic Carrier Bags Solutions through Innovation' Defra research call, p27 Back

144   Q111 Back

145   Waitrose (BAG 027), para 3.9 Back

146   Q117 Back

147   O'Brine, T. and Thompson, R. 'Degradation of plastic carrier bags in the marine environment'. Marine Pollution Bulletin, 2010. 60(12): p. 2279-2283 Back

148   Qq131-133 Back

149   Additional evidence from Mr Newman (BAG 039), para 5.5. Back

150   Irish Government Biodegradable bags Back

151   Waitrose (BAG 027), para 3.11 Back

152   Marine Conservation Society (BAG 013)  Back

153   Professor Thompson submitted evidence that states "It is unlikely that a material can be developed... that will also completely degrade into harmless constituents within a sufficiently rapid timescale (i.e. a time scale that would prevent the negative impacts on wildlife, aesthetics and economy) when the bag becomes litter in the environment" (BAG 030) para 2.He was also a joint author of an article in the journal Nature (494 pp169-171, 14 February 2013) titled 'Policy: Classify plastic waste as hazardous'. In addition, the European Parliament published a 'Green Paper: On a European Strategy on Plastic Waste in the Environment' in March 2013 states (p6) "micro-plastics... may have a high potential for contaminating the food chain through predator-prey interaction"  Back

154   Defra (BAG 032), para 18 Back

155   Oral evidence taken before the Environment, Food and Rural Affairs Committee on 29 October 2013, Departmental Annual Report 2012-13 HC741 Departmental Annual Report Q105 Back

156   Axion (BAG 014), p2 Back

157   Q104 Back

158   Q105 Back

159   Co-operative Group (BAG 040, para 4.2. Back

160   Co-operative Group (BAG 040); Currently Oldham Council subsidises compostable bags at 3p, but this only makes sense when the alternative is free, and continued subsidy is unlikely to be the best use of public funds. It would not be desirable to make a compostable bag cheaper than a conventional bag as it could lead people to thoughtlessly take this kind of bag because it is cheaper without intending to use its correct disposal. Guidance and possibly regulation around the correct disposal of these bags would be necessary in any case.  Back

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Prepared 6 February 2014