Plastics and the Marine Litter Debate
The packaging industry continues to be roiled by the debate around the use of plastics and their potential impact both in the marine environment and more generally through littering and unmanaged waste disposal.
This article discusses the causes of litter from packaging, considers actions that can be taken to minimize such littering and ponders the trade-offs that might be associated with moving away from plastic packaging.
The Causes of Litter
When thinking about what actions are appropriate to reduce the environmental impacts of unmanaged waste, it is first worth considering those factors that contribute to littering in the first place. These cover a range of diverse topics including social norms and expectations, market conditions, regulations and laws, waste management technology and infrastructure.
Lack of social responsibility – people who litter intentionally, or just through carelessness, must take much of the blame. This behavior embodies a lack of a sense of social responsibility for their local environment by litterers, which may be given license by a general acceptance of littering by society in general.
Lack of regulations and laws – the perceived social acceptability of littering (or, at least, the lack of sufficient social disapproval) is closely linked to the inadequate enforcement of legislation on littering. When there are no perceived personal consequences, there is little incentive to change behavior.
Packaging design – design has a very important role to play in managing the littering issue. Moving away from single-use packaging to reusable options will require a change in mindset by consumers but can certainly be achieved (witness the success of the UK plastic bag tax in changing consumer behavior during the “weekly shop”).
A lot can also be done to make packaging easier to reuse and recycle, and to be made from materials that have higher quantities of recycled content, which further reduces manufacturing burdens.
Design solutions can also be developed to make unintentional littering more difficult, for example by replacing or redesigning tamper-proof tear-off strips that are easily mislaid or accidentally discarded, even by well-meaning and responsible consumers.
Inadequate infrastructure – there needs to be sufficient waste treatment capacity and appropriate technologies available to effectively collect and manage the waste that is generated by society. This is a critical problem in many emerging economies where such infrastructure may be completely lacking, but this is an issue for many more developed countries too.
Economy of recycling – one of the issues contributing to litter is the low value of recycled packaging material and the high costs of treatment. If recycled material is more expensive than virgin material, there is no incentive for packaging manufacturers to use it.
The Influence of Material Choice
Why banning plastics will not save the environment
One of the biggest influences on the environmental performance of packaging is the choice of materials used.
In the debate on marine litter, plastics have been identified as the major culprit. As a result, a common knee-jerk reaction has been to propose banning plastic packaging entirely. In the UK there has been much discussion on potential bans on plastic straws, cotton buds and disposable coffee cups with plastic linings. Iceland, a supermarket chain, has even introduced “plastic-free” aisles and promised to phase out plastic in its own-brand products.
However, before making such decisions, it is important to consider the wider consequences. Plastics are widely used in packaging, due not only to their low cost, but because they have a number of desirable physical characteristics, including flexibility, low mass, strength, impact resistance and good barrier properties.
In most cases, a ban on plastic means that some other type of packaging material will be required to take its place. This material may not perform as well on the above measures and will often have their own environmental challenges and impacts. When selecting among materials it is important to understand the consequences and potential trade-offs associated with each choice.
Making material substitutions may be the best thing to do in some applications, but not all. The UK plastic bag tax has reduced the number of disposable plastic bags used by around 90% since it was introduced. But a study by the UK Environment Agency found that the carbon footprints of some possible replacement materials were very high. A cotton tote bag would have to be reused 131 times just to break even in terms of greenhouse gas emissions—if some of the disposable bags are actually reused as bin-liners then even more reuses are required just to reach parity .
Replacing plastics with natural fibres may mean that we solve the problem of marine litter at the cost of creating another problem—deforestation.
Researchers in Scotland also recently reported that a total ban on plastics in packaging could lead to a tripling of greenhouse gas emissions, because the alternative materials used have higher carbon footprints that the plastics they replace .
Similarly, replacing plastics with natural fibres may mean that we solve the problem of marine litter at the cost of creating another problem—deforestation—to make room for growing the source crops needed for this substitution.
So, the apparently straightforward response of simply banning plastics in packaging may not result in an equally straightforward outcome that is better for the planet overall. It can be difficult to balance and judge the relative importance of different types of environmental impact. In many cases, substituting other materials in place of plastic may make sense, but these need to be evaluated on a case by case basis and with consideration of a range of potential impacts, not just marine litter.
If we accept that, for some packaging applications, plastics do provide some environmental benefits compared to alternative materials, what types of plastic should we use?
Biodegradable or compostable polymers could be one way to greatly reduce the problems of marine litter, as they have the potential to naturally degrade over time. However, often these polymers, such as polylactic acid (PLA) need industrial composting conditions to decompose rapidly, requiring relatively high temperatures of around 60 degrees C, and specific moisture levels. They will not break down in your home compost. Indeed, new research has shown that such “biodegradable” plastics may remain largely intact even after three years of being buried in soil or floating in the ocean . To be fair, the compostable—presumably “home compostable”—plastic did perform much better, completely disappearing from the marine environment within three months, although even this did not fully decompose in soil, even after three years.
Biodegradable polymers may have some additional problems of their own.
Depending on the source crops and the energy sources used for processing these into finished biopolymers, the environmental burdens associated with manufacturing these materials can vary greatly.
They may compete for land with other applications such as food crops, and so potentially contribute to deforestation.
The waste management infrastructure required for dealing with biodegradable/compostable polymers is generally incompatible with that for recycling conventional plastics.
Recycling and recycled content
Another option is to focus on recyclability and favor conventional plastics that are easy to recycle, such as PET, PP and PE, while avoiding materials such as PVC and PS that are less easy to recycle or that have other environmental issues of concern.
Additionally, we can seek to increase the proportion of recycled content in the plastics we use. Companies such as Danone and Coca Cola have set targets to reach 50% recycled content in their plastic packaging. The UK Government recently held a public consultation over proposals to tax plastic products with less than 30% recycled content more heavily, to provide a price incentive to encourage the use of recycled content. Higher recycled content products should have the dual virtues of both reducing the environmental impacts associated with packaging manufacturing and increasing the value of secondary plastics, thereby further incentivising recycling and making it less likely that packaging waste is discarded as litter.
The Role of Packaging Design
Packaging designers and innovators have an important role to play in improving the environmental performance of packaging. Below I discuss some key eco-design guidelines for developing packaging that is easier to recycle and more difficult to inadvertently litter.
Design for reuse and recycling
Currently, a key focus is to try to eliminate “one-way” or “single-use” packaging (packaging that is used once and then discarded) in many applications.
As with the carrier bag example discussed earlier, it is important to understand how many times the product would have to be reused to achieve acceptable performance for other environmental impacts. This can help product designers achieve the optimal solution.
Packaging designers and innovators have an important role to play in improving the environmental performance of packaging.
For example, some companies have started selling reusable stainless steel straws to replace disposable plastic straws. Is this an optimal solution? Stainless steel is a very high impact material. How many times must a reusable stainless steel straw be reused for it to have a carbon footprint equivalent to the plastic straws it replaces? Would a robust, reusable and recyclable plastic straw, with a much lower manufacturing impact, actually be a better choice for this application?
Staying on the topic of straws, it was interesting to read that McDonalds has replaced its plastic straws with paper ones in all its stores in UK and Ireland as "part of wider efforts to protect the environment." However, it has now admitted that the new paper straws cannot be recycled by their waste solution providers, whereas the replaced plastic straws could . Is this progress?
Minimise the number of different materials used
Reducing the number of materials used in a packaging design makes it easier to recycle as fewer parts have to be separated. There is also a trend toward moving to use mono-materials for composite films. Traditionally, such films comprise different materials that are glued together, rendering them nearly impossible to recycle. Some producers are now offering films that still contain multiple layers, but made of compatible materials that can be recycled together (e.g., composites made of different PE film layers).
Avoid “tear-off bits”
Many packaging formats have small parts or film coverings that need to be torn off to access the product. Often these are related to tamper-proof seals and other security features that play an important role in ensuring product safety.
However, such “tear-off bits” are easily mislaid and inadvertently littered even by conscientious consumers. Innovative packaging developers should aim to redesign such features so that they remain attached to the packaging or can be eliminated entirely.
Avoid colored and black plastic
In general, you should avoid colored and black plastic, because the value of recyclate from colored packaging is lower than that for clear packaging—clear polymers provide the greatest flexibility for recycling into other products.
Black plastic packaging made using carbon black as a pigment is also difficult to separate using near infra-red sensors that are commonly used in Materials Recovery Facilities, limiting the ability to recycle it. “Detectable” black pigments are available, but this would still result in recyclate that is of lower value than clear plastic.
In general, you should avoid colored and black plastic, because the value of recyclate from colored packaging is lower than that for clear packaging.
Some companies are starting to market “natural” recycled plastic packaging that contains no additional pigments. The color of the packaging will vary somewhat from batch to batch, depending on the input material, but this provides a use for lower grades of recyclate, containing darker colored flakes, that might otherwise end up being incinerated or landfilled.
The options available for treating waste packaging at end of life also have a critical role to play in determining environmental performance and should be considered by innovation teams when looking at new packaging designs.
Consistent waste infrastructure
It greatly helps consumers to understand what to do with their waste packaging if there is consistent messaging from packaging manufacturers and the same options are available to everyone. This consistency is also essential in ensuring that the growing demand for recycled plastic can be met.
In some countries, such as the UK, collecting and managing municipal waste is the responsibility of local authorities, with little or no overall coordination at a national level. This means that the choice of which materials to collect for recycling and how such collection is managed varies greatly depending on region. Because different options are available in each location, it is hard to promote a single message for what the best choice is for a given packaging format, and this can confuse and frustrate consumers.
Happily, this may change, as the UK Government has recently undertaken a public consultation exercise on improving consistency in recycling collection. Hopefully this will result in actions to improve alignment on waste management options across local authorities.
Separation and treatment of biodegradable and non-biodegradable polymers
Waste management companies regard biodegradable and non-biodegradable polymers as incompatible in terms of treatment options and seek to keep these classes of plastic separate. Biopolymers are considered a contaminant in conventional plastic waste streams and reduce the value of the waste plastic collected. Equally, discarded conventional plastic will contaminate a bio-degradable polymer waste stream as it will not decompose and so will reduce the value of the resulting compost. Plastics Recyclers Europe, a trade body representing recycling organizations, notes that “Mixing the traditional and biodegradable plastics in the waste streams puts in jeopardy current efforts to increase plastics recycling rates. With the increasing production of biodegradable products, it is essential to implement separate collection schemes for bio-waste.” 
It will be challenging to get consumers to reliably separate these plastics at source. So, to be effective, waste contractors will have to sort after collection.
Some UK local authorities collect compostable waste, but biodegradable/compostable polymers are not accepted in these collections, presumably because of the high likelihood of accidental contamination with non-biodegradable plastics. This means that even if biodegradable polymers are used in packaging, it is very difficult to dispose of them such that they will end up getting composted once discarded. Currently it is more likely that waste management companies end up incinerating or landfilling biodegradable polymers, although incineration with energy recovery may be a relatively favorable option for these materials.
Even if biodegradable polymers are used in packaging, it is very difficult to dispose of them.
In short, if we are to use biodegradable polymers extensively in our packaging mix, it will be necessary to better manage their separation and treatment at end of life. Manufacturers of such packaging options may need to take more responsibility for promoting and enabling the infrastructure necessary to achieve this.
New technologies for recycling
Most plastics recycling relies on tried and tested mechanical reprocessing, whereby the polymers are sorted, shredded, cleaned and re-extruded back into secondary granulate. However, chemical recycling technologies, such as pyrolysis and gasification (amongst others), have been used and tested at a relatively small scale for a number of years. These processes can break down waste polymers into their component chemicals that can be used to make virgin-equivalent quality plastics, as raw materials for other chemical processes, or can be turned into fuels.
Chemical recycling may prove to be particularly attractive as a recycling route for less widely recycled polymers, or for low grade mixed polymers, for which mechanical recycling is not economical. These may include plastics that only arise in small volumes or that are hard to sort, composite films or material that is heavily contaminated. If these technologies can be used at scale (and shown not to have their own environmental issues), they would potentially represent a significant improvement in how we deal with polymer wastes.
Improve infrastructure in emerging economies
As has been widely reported, a study by researchers from the Helmholtz-Centre for Environmental Research GmbH – UFZ, found that around 90% of plastic that ends up in the ocean comes from just ten river systems in Africa and in South and Southeast Asia . A major reason for this is the critical lack of waste management infrastructure in the countries through which these rivers pass. One of the most effective actions to reduce marine litter will be to improve this infrastructure.
Thankfully some groups are working to make this happen. Organizations such as Circulate Capital provide funding for private capital investment to support the recycling value chain in South and Southeast Asia. Meanwhile Plastic Bank seeks to improve infrastructure and incentivise collection of waste plastic by paying an above market rate for plastic waste and enabling waste collectors to trade plastic for money, goods or services.
It must also be noted that much of the marine litter that comes from these regions is ultimately sourced from more developed countries such as those in North America and Europe. For many years these countries have outsourced the problem of dealing with their packaging waste by exporting it to other, invariably poorer, countries that often lack the resources necessary to manage it responsibly.
Countries that produce packaging waste must now find ways to manage this themselves.
This is unsustainable, especially now that China and other receiving countries are closing their borders to most types of imported waste. As is right and proper, countries that produce packaging waste must now find ways to manage this themselves. This also means that improving waste infrastructure is not only a priority for emerging economies: more developed countries must devote resources to developing and improving their own waste infrastructure if they are to reduce the environmental impact and extract more value from their waste streams by diverting material to recycling rather than to landfills or incineration.
Influencing Consumer Behavior
Ultimately, much of the responsibility for littering rests with the consumer. It is up to the individual to ensure that packaging is disposed of responsibly. A number of actions can be taken to incentivise good habits and behavior. Many of these tie in with previously discussed points regarding packaging design and waste infrastructure.
Better labelling - clear on-pack labelling and guidance on how waste packaging should be treated can help consumers make the right choice when selecting disposal routes—should it go into the recycling bin or general waste?
Provide incentives to increase reuse and recycling - deposit-return schemes encourage people to return used packaging for reuse or recycling by charging a small additional fee on purchase that is refunded when the packaging is returned. It is also increasingly common for coffee shops and cafes to provide discounts to customers who bring their own reusable cups.
Campaign to make littering socially unacceptable – we can change behavior and adjust social norms thorough societal pressure. Drunk driving used to be commonplace, but with effort and campaigning, it is now no longer tolerated. If littering is seen to be shameful, and litterers shunned, maybe it can also be made socially unacceptable.
Enforce penalties for littering/fly tipping, etc - in the UK, millions of pieces of litter are dropped every day, but few culprits will end up being fined or face other consequences. This encourages a sense of impunity among litterers. There is little incentive to change behavior if there are no consequences for wrong-doers.
The debate around plastics and marine litter has been raging for a couple of years now and shows no sign of abating. Simply banning plastic packaging will not result in net benefits for the environment, as alternative packaging materials will have their own, different, environmental problems.
It does make sense to review the packaging materials that we use to ensure these are the most environmentally friendly available, but we should do this in a broader context than just by focusing on marine litter. It is also important for us to include climate change, deforestation and other environmental impacts in such assessments.
When selecting materials for packaging and the packaging specification itself, it is important to consider whether we can design so as to reduce the chance of littering, to make it easier to recycle or to have a longer life and be reused. We must also think about whether the waste management infrastructure in the location where the products will be sold is sufficient to separate and recycle the materials used in the packaging.
Finally, as a society, we need to put the right financial incentives in place and apply sufficient social pressure to influence consumer behavior such that more waste packaging is collected and processed appropriately, and not discarded as litter.
 Schmidt, C., Krauth, T., Wagner, S. (2017): Export of Plastic Debris by Rivers into the Sea. Environ. Sci. Technol. DOI: 10.1021/acs.est.7b02368 (https://pubs.acs.org/doi/10.1021/acs.est.7b02368)