Mark Hilton takes a look at plastic packaging, as the issue of its environmental impact has never been higher on the agenda

There has probably never before been such widespread concern about the impact of plastic packaging.

It seemed a niche issue just a couple of years ago – but the effects that littered plastics in particular are having on the environment have now reached mainstream prominence as part of the wider Circular Economy (CE) agenda. Recent weeks [at time of writing] have seen the impacts of plastic litter made manifest on David Attenborough’s Blue Planet II series, and condemned on newspaper front pages. Even the Treasury has taken heed, with Budget 2017 announcing a call for evidence on ‘how the tax system or charges could reduce the amount of single-use plastics waste’.

Of course, the plastics that are littered tend to be the ones used to package the subset of products that are most often consumed on the go – drinks, crisps, confectionary and the like. However, a far wider range of foods come in plastic packaging, and according to Defra only 38 per cent of the UK’s plastic packaging is currently recycled – despite the majority of councils now collecting bottles, pots, tubs and trays. That means a great deal of plastic packaging is ending up being landfilled or burned, when it could be used far more beneficially and with lower environmental impact.

Plastic is tremendously useful, and has many advantages in fulfilling food packaging’s primary purpose – making sure that food gets to its destination in good condition and with plenty of shelf life. The environmental benefits of avoiding food waste are huge, and moving away from certain types of plastic packaging is only an attractive option if there are alternatives that can achieve the same benefits and yet still allow a lower overall carbon footprint, ideally with less litter and more recycling.

Care has to be taken when switching materials. Paper-based packaging can seem an obvious choice for some food products as it fits the image of healthy foods, is easy to recycle and will compost. Cardboard, however, generally needs a greater weight of packaging to do the same job as plastic, and assuming both are recycled, the carbon footprint of card will tend to be larger. Packaging also often needs to provide a ‘barrier’, for example to grease, moisture and gasses, which further complicates the picture. Plastic barrier films are often used which make both cardboard and plastic packaging harder to recycle.

Bio-degradable polymers may seem attractive, but they do not degrade easily out in the open as litter, and are currently hard to distinguish from regular plastics in waste management streams, causing issues for both plastics recyclers and centralised composting sites. Bio-polymers however can be useful where they can be easily identified (e.g. colour coded composting bags) and in terms of reducing the overall carbon impact of packaging when blended with regular polymers; as is the case with the Coca-Cola Plantbottle which can be recycled easily with other PET packaging.

Litter issues aside (which need a different approach from recycling), regular plastics often remain a good choice, but more needs to be done to increase the size of the sweet spot that allows excellent food protection and greater recyclability. One of the biggest frustrations for councils and waste companies is the widespread use of black plastic for food packaging. Sorting plants separate different polymers using near infra-red (NIR) technology, but infra-red beams are absorbed by carbon black, rather than reflecting them. Without separating black PET from black PP for example, the material becomes low value and hard to use. China has been a huge market for UK mixed plastic, but is closing the door to low quality material. That makes effective separation of polymers and colours of increasing importance.

There are very few absolutely compelling practical reasons to use black plastic, the main one being to completely protect products from UV deterioration due to exposure to light. For the most part, the reasons why it is used are aesthetic; for example to show off the redness of meat and is often used as a signifier of high quality ranges. There are already solutions in the form of alternative black pigments that are NIR detectable (proven through trials back in 2007), although these add a little cost. Some supermarkets are now using dark grey plastics that can deliver much the same aesthetic benefits and are compatible with NIR sorting.

Another rationale for the use of black plastic is that it provides a use for many other coloured plastics; they can be recycled together and black pigment added to provide a uniform colour. Dark grey would allow this practice to continue, but producers could help still further by trying to avoid adding coloured pigments to plastics in the first place. If more plastic packaging is clear (rather than opaque, which still presents problems), it will be easier to recycle and be more attractive – and more valuable – to reprocessors.

Some of the more proactive supermarkets are moving along the simplification agenda, replacing black packaging where possible with clear, and also by reducing the range of polymers in play and by making them easier for recyclers to identify. By focusing on the three main polymers that already have good markets, namely PET, LDPE/HDPE and PP, whilst limiting the range of additives and barrier films that restrict recyclability, helps to minimise the costs of sorting and reprocessing whilst improving the value of the resulting recyclate. This all helps to ensure a viable and stable UK reprocessing sector.

Financial incentives, like those that could result from a tax or charge, have the potential to drive innovation, and there are a number of developments that could help get rid of unnecessary plastics and improve the recyclability of those that are. There are now recyclable barrier papers on the market for confectionary, for example, that have no plastic laminate or metallised layer.

There can, of course, be a case for more complex and less recyclable packaging if this increases food protection and shelf life, however it is critical that such packs can be identified. That’s something that better marking and tracking of items could help with and manufacturers are exploring the use of simple fluorescent markers to aid identification and printed and embossed ‘watermark’ technology (which will eventually replace product barcodes) to give far richer and more readily scanned information about the key characteristics of the material used.

There is no shortage of packaging innovation, but that doesn’t always mean lower carbon footprint or greater recyclability in the short term. There is also a wide range of good environmental practice within individual firms and through industry initiatives, but unfortunately market forces and voluntary action alone seldom seem to provide the mass market changes that are required to move plastic packaging quickly towards a more circular economy.

What the UK food and drink sector needs in this regard is carefully considered government action that drives the CE agenda whilst providing a level playing field through regulatory and/or economic stimulus. It is to be hoped that the forthcoming call for evidence around potential charges or taxes for single use packaging will be the first step in making this a reality, without imposing undue costs on consumers.

Mark HiltonMark Hilton is Resource Efficiency Lead at Eunomia, based in the company’s Manchester office. Established in 2001, Eunomia Research & Consulting Ltd (Eunomia) is a Bristol-based, independent consultancy dedicated to adding value to organisations through the delivery of improved outcomes. Working throughout the UK, other EU Member States and beyond, Eunomia’s consultants have experience and expertise in environmental, technical and commercial disciplines.