Are plant based plastic alternatives sustainable? Here’s what you need to know

 The world is facing a plastic crisis. Each year between 5 and 13 million tonnes of plastic end up in the ocean, and the amount of plastic produced and consumed is expected to double by 2030. As a result, many people are looking for alternatives to traditional plastic products. Plant-based plastics are often seen as a potential solution to this problem, but are they truly sustainable?

Bioplastics are a common plastic alternative. They are made from renewable resources such as corn, sugarcane, and vegetable oil. They are typically labelled as biodegradable and compostable, meaning they can be broken down into smaller parts. Additionally, they often require less energy and water to manufacture than traditional oil-based plastics.

However, bioplastics have their own set of sustainability issues. For instance, many bioplastics are made from crops that require large amounts of water and fertilizer, and their production can lead to soil degradation and water pollution. Additionally, bioplastics may not be as durable as traditional plastics, meaning they may need to be replaced more often.

Bioplastics are definitely not the same as your fruit and veg leftovers. For a bioplastic to be described as biodegradable it needs to pass the EN13432 test for industrial composting – this means it must disintegrate in 12 weeks and biodegrade within 6 months in an industrial facility, with 90% or more converted to CO2. Certainly not the same as your carrot peelings! Biodegradable plastics just mean the material can be broken down into smaller parts – however what remains after this process may still be harmful to the environment. If bioplastics are incinerated, they can release toxic gases into the atmosphere.

Compostable bioplastics need certain conditions to correctly break down and can’t be thrown on your compost heap. Compostable packaging needs the specific conditions on an industrial anaerobic composting facility. They are currently not collected by any council in the UK, meaning these compostable plastics have to be put in your regular rubbish bin. Compostable bioplastic is not a solution to plastic pollution and is only better than the traditional plastic option if there is a system in place to have it correctly composted after use. For example, PLA (polylactic acid) is a compostable polymer which is made from plant based sources like corn starch and sugar cane. Often used for plastic bottles and coffee cups it is not recyclable.

What about recyclable bioplastics? Some bioplastics like bio-PET are recyclable, but most are not, and since public collection facilities do not generally exist for bioplastics, they are very rarely recycled.

Reusable cups all try to replace single use plastic cups with a more sustainable option. One such alternative is the bamboo cup. Do they offer a truly sustainable alternative to the single use plastic cup? Sadly not.

Bamboo cups can not be made from bamboo fibres alone. They need the addition of melamine resins (plastic) to hold the cups together. The chemicals involved in making these cups are toxic to both people and the environment which has sustainability implications. As they contain melamine they will not biodegrade and can not be composted in industrial facilities. They can also not be recycled in traditional recycling plants – leaving incineration for energy as the only option.

A survey done in 2019 by the German consumer organization Stiftung Warentest, shows most bamboo cups release significant amounts of toxins into the drinks inside. These bamboo cups can degrade when put in the microwave or dishwasher, or even when filled with hot liquids.

Furthermore, Bamboo fibres are not authorized as additive for plastic food contact materials. Therefore, placing these bamboo/melamine food utensils on the European market is illegal.

We then look at recycled plastics as an option for a reusable cup. While still composed of plastics, items made from recycled plastics are passed off as being the sustainable alternative. But is that true?

Recycling single use plastic into something of use is applaudable and definitely better than manufacturing more virgin plastic. But plastic can only be recycled 2 or 3 times in its lifetime, meaning virgin plastics have to be mixed in with recycled plastics to make a new product. So reusable cups made from recycled plastic are not endlessly recyclable, like glass or steel options would be, and will need new plastics added in to turn them into a new product at their end-of-life.

Alongside that, if using cups made from recycled plastic bottles or coffee cups you need to consider you own exposure to microplastics. These microplastics can enter our drinks from these recycled plastic cups and the affect this has on our health has still to be fully understood.

While these plastic alternatives may have some advantages over traditional plastics, they are not a silver bullet solution to the plastic crisis. The EU is planning to ban problematic bioplastics, and the EU single-use plastics directive calls for a sustained reduction in single-use materials, including bio-based and biodegradable plastics. Will the UK adopt a similar stance?

We need to consider that plastic is not endlessly recyclable, so when recycling it we should be making items with long lifespans – something like home insulation will last for years compared to the months a recycled plastic cup may last for. We also need to be aware that options like bamboo cups, sold as a natural reusable alternative to plastic, in fact still contain plastics and can’t be recycled or composted so are not a good step towards a circular economy.

Ultimately, to reduce plastic pollution we need to say no to single use plastics, whether they are traditional oil-based plastics or bioplastics. When looking for alternatives to single use plastic we should look towards items that are endlessly recyclable and are designed to have a long lifespan. For the reusable bottle and cup industry that would mean looking at either a reusable bottle or cup made from steel or glass. Both materials are endlessly recyclable and last a long time.