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| Photo from https://www.thenational.ae/lifestyle/can-plant-based-degradable-plastic-solve-the-problem-1.746423 |
With the recent series of Blue Planet highlighting the magnitude of plastic pollution in our oceans, the general public have taken a greater interest in reducing the plastic we use which is definitely not a bad thing considering the fact that annually eight million tonnes of plastic waste enters our oceans. We as a society are heavily dependant on plastics with even the most eco-friendly of households still throwing away a large amount of plastic. 300 million tonnes of plastic are made each year 10% of which is recycled and just over 40% of plastics only being used once before discarded. Needless to say I get very excited when I see supermarkets seeing biodegradable bin liners and cling film but are these truly environmentally friendly and a permanent solution to our plastic problem?
Firstly, there is a major difference between bioplastic and bio-degadable plastic. Bioplastic are made from completely renewable sources that are biologically based ranging from corn oil to starches. these mean these breakdown naturally in the environment and are 100% compostable as they only contain organic matter. Bio-degradable plastics are still chemical based and still include petroleum based chemicals but have additives that causes a quicker breakdown in the environment. The words photodegradable and oxydegradable are probably a better way to describe these types of plastics. Due to the chemical content, there can still be toxic residue produced meaning these plastics cannot compost as some of the chemical residue can inhibit plant growth, unlike the bioplastics. There have also been reports that bio-degradable plastics still produce micro plastics which are easily ingested by fish and plankton and bioaccumulate up the food chain. It has been reported that in the North Atlantic Ocean, 73% of fish have ingested some form of plastic. Even though these bags do produce less plastic fragments and breakdown quicker than conventional plastic, bioplastic seems to be a better solution to this problem as it stops plastics from entering the ecosystem. However, my view is any option is still better than producing more conventional plastic.
Ignoring these differences, I thought it would be interesting to compare the differences between biodegradable plastics and conventional, petroleum based plastics. The first major advantage is that there is a lower oil consumption, mainly during the manufacturing process. Globally, 8 to 10% of all oil is used to created plastic and in the USA alone, 12 million barrels are used every year just for carrier bags. The lower fossil fuel consumption will lead to less CO2 emissions and subsequently a reduction in the enhanced greenhouse effect. However it does put into question if we would actually be saving oil because it will more than likely still be used, just for other purposes. Despite this, biodegradable plastics produce, on average, 0.8 tons of CO2 during production which is much lower than conventional plastic that produces 3.2 tons. This means the carbon footprint is significantly lower as well as reduced consumption of finite resources. Obviously 100% bioplastics are renewable but biodegradable plastics still require far less oil.
Another key advantage is the quicker rate of decomposition means that landfill and solid waste will be produced. Although there will be a need for composters, this will result in a much cleaner environment and the impact of plastic on biodiversity will be reduced. Considering that annually roughly 10,000 turtles consume carrier bags (as they mistake them for jellyfish) and decline should be accepted and the quicker rate of decomposition should help to reduce this number.
One main disadvantage is more of a social issue (presented by environmental sceptics) and is that it will encourage people to litter. To some extent I agree with this statement because one of the key points of anti litter campaigns is the environment and laziness could kick in. Would all of the general public stop to pick up their rubbish if they knew it would biodegrade? It is also worth pointing out this is still not the solution to litter and our waste problem as even though the residence time is significantly shorter, they still remain in our environment for a long period of time which could still lead to ingestion by wildlife and pother issues such as water pollution.
Another issue is cost. Not only are biodegradable plastics more expensive to make (due to a more complex manufacturing process) but they are also more expensive for consumers. As a student, I can say that my peers would be less likely to spend more on the simple things like bin liners and other single use items. This may also be the same issue for families or others on a budget. Even though they may only be £2 extra, to some that is a meal or a drink out. Given the choice many people will chose the cheaper option and until we can reduce the manufacturing process I fear that petroleum based plastics will still be the norm.
Whilst I believe bio-plastics are the future, the technology is very limited meaning it will be a while before they completely replace 'normal' plastic. They say you vote with your dollar (or pound) so as consumers we need to make small changes to the biodegradable options to encourage supermarkets to invest in bio-plastics.
References -
- https://news.nationalgeographic.com/news/2015/02/150212-ocean-debris-plastic-garbage-patches-science/
- https://www.ecowatch.com/22-facts-about-plastic-pollution-and-10-things-we-can-do-about-it-1881885971.html
- https://www.explainthatstuff.com/bioplastics.html
- http://www.craftechind.com/pros-cons-biodegradable-plastic/
- https://plastics.americanchemistry.com/Life-Cycle-Assessment-for-Three-Types-of-Grocery-Bags.pdf
