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Bioplastics: in or out of the loop?

By July 9, 2020August 27th, 2020No Comments

As more companies and consumers are drawn towards the novelty of bioplastics, are we jumping the gun and is it too soon to tell whether the benefits will outweigh the costs?

Bioplastics, or bio-based plastics are plastics made from any type of renewable biomass materials, such as vegetable fats, corn and wood pulp. Some companies are even experimenting with making bioplastic polymers out of “air”, or a combination of carbon dioxide and light. Although bioplastics reduce reliance on fossil fuels and can be an efficient way to re-use organic materials, such as food waste and saw-dust they aren’t necessarily the silver bullet.  

One of the main ‘green’ selling points of bioplastics is that they will degrade or compost. However, with many bioplastics having similar properties to petroleum-based plastic this is only partially true and only under specific conditions. As a rule of thumb:   

“Not all bio-based plastics are compostable and not all compostable plastics are bio-based.” 

While some bioplastics may degrade naturally in a home composting bin, some will only do so if they make it to the correct industrial facility where they degrade under very high temperature conditions. These types of facilities are in short supply in the UK, with the result being that many bioplastics end up landfill or in oceans where they will not necessarily break down. Last year, a Footprint investigation revealed that despite best efforts, bio-based compostable packaging from the UK Houses of Parliament were incinerated due to problems arising within the waste collection supply chain.   

Bioplastics are almost indistinguishable from regular plastics, contributing to plastic recycling stream contamination. Furthermore, others have suggested that bioplastics have minimal end of life value to composters to sustain a market for collection, making a stronger case for supporting established markets for recycling existing materials.  

When it comes to environmental credentials, some studies do suggest that replacing conventional petroleum-based plastics with bio-based plastics reduces carbon emissions, but it is too soon to tell whether the benefits will outweigh the costs. According to Jenna Jambeck, professor at the University of Georgia, bio-plastics currently raise more questions than answers: “Where is it grown? How much land does it take up? How much water is needed?” she asks.  

The effect which an influx of bioplastics could have on consumer recycling behaviour is also questionable. A study from Wageningen University indicated that consumers are more likely to incorrectly dispose of compostable bio-based packaging than regular plastic packaging – even when disposal instructions were placed on the wrapper. Furthermore, one could ponder the ethics of using increasingly scarce cropland to make single-use packaging, rather than feed a growing population.  

While bioplastics remain an attractive idea and perhaps a novel way to reuse materials such as food waste, achieving success appears a long way off and if not done carefully can cause hindrance and disruption to a circular economy. Rather than adding new materials to an already complex mix, the focus should be on strengthening and making more robust the solutions that are readily available – like plastic recycling.