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An estimated 8 million tonnes of plastic waste are dumped into our oceans each year. With public demand for alternatives to petrochemical plastics so high, new technologies are creating ‘eco-friendly’ materials to combat the problem: But do they really offer a solution?
Plastic Pollution Problem
Since the 1950s, it is estimated that a staggering 8.5 billion tonnes of plastics have been produced, with only 9% having been recycled. Plastic is fundamentally designed to be durable and long-lasting, and has a range of useful applications across most major industries, yet over the past few years our dependence on plastic has been under scrutiny, due to the amount that has accumulated in the natural environment. Over 70% of all waste found on beaches is plastic, and tiny plastic particles, invisible to the naked eye, have been found in our fish, seafood and even sea salt.
Typical Materials and Issues
The most common synthetic plastic is polyethylene (PE). Primarily used in packaging, such as plastic bags and bottles, it constitutes over one third of all plastics on the market. Due to its ductility, versatility and relatively low production costs, PE is widely used for single-use plastics: goods which are used for an average of 12 minutes, yet with a lifetime of hundreds of years. Unfortunately, most synthetic plastics have an equally long lifetime and do not readily biodegrade - posing a huge strain on our landfills and natural environments. Although many plastics are recyclable; consumer apathy and improper recycling infrastructure means that a huge proportion of technically recyclable plastics still make their way to landfill or, ultimately, the oceans. An added concern is that, when exposed to solar radiation, many plastics release greenhouse gases which further contribute to climate change and drive a whole different host of environmental issues.
Biodegradable Plastics
The heightened concern surrounding plastic pollution has seen the rise of new developments in of “biodegradable” and “compostable” plastics. In theory, these materials aim to limit the effects of plastic pollution by replacing typical plastics with materials which will degrade much more quickly and readily in the environment. Oxo-biodegradable plastics became a popular starting point: Plastics with additives susceptible to heat, light and moisture, to catalyse the degradation process. Unfortunately, studies showed only a few percent decrease in plastic surface area over a 40-week period compared to a standard plastic, and that they were also non-recyclable by traditional methods which caused problems in local recycling facilities. Perhaps the largest criticism is that these are still comprised of petrochemicals which will leech into the environment one way or another, regardless of the time period over which they biodegrade.
Bioplastics Made from Raw Materials
Some plastics have been derived entirely from raw biomass sources such as food waste, corn starch and vegetable fats. At first glance, these bioplastics seem to offer a solution to the plastic pollution problem, but they have been criticised as merely displacing the issue and providing consumers with a false sense of eco-security. The most common bioplastic is Polylactic acid (PLA) which is derived from fermented plant starch. A large number of retailers, especially within the food and drink industry, are now sourcing PLA products to replace traditional disposable plastics such as straws, coffee lids and cutlery. Whilst these materials may biodegrade more readily, they still have very specific temperature and pH requirements to do so; conditions not typically found in local composting sites, and almost never achieved in landfills.
Ditching the Disposable Mindset
There is criticism that the rules for achieving ‘eco-friendly’ status are too weak, and that manufacturers should be required to be more transparent about the true environmental impact of their products. As awareness of plastic pollution continues to grow, there are more and more innovations aimed at producing truly ‘earth-friendly’ products to replace disposable plastics, such as home-compostable disposables. However, consumers are being urged to turn away from single-use items wherever possible, opting instead for simple switches which have a cumulative effect: buying a reusable water bottle and coffee mug, bringing bags to the supermarket, reusing food containers and repurposing everyday items for continued use.
References
- Plastic pollution facts https://www.globalcitizen.org/en/
- Plastics: The Facts 2017 https://plasticseurope.org/
- Production, use, and fate of all plastics ever made. Roland Geyer, Jenna R. Jambeck, and Kara Lavender Law, 2017 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5517107/
- Spotlight on: oxo-biodegradable plastics
- “Biodegradable” Plastics: A Myth of Marketing? lK.G.Harding, T.Gounden & S.Pretorius, 2017 - https://www.sciencedirect.com/science/article/pii/S2351978916301901
- Production of biodegradable plastic from agricultural wastes. N.A.Mostafa, Awatef A.Farag, Hala M.Abo-dief, Aghareed M.Tayeb, 2018 https://www.sciencedirect.com/science/article/pii/S1878535215001100
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