Easy to make, hard to get rid off.
A world without plastics seems unimaginable today, yet their large-scale production and use only dates back to ~1950. The rapid growth in plastics adoption since is extraordinary, surpassing most other man-made materials. Plastic is cheaper, lighter, and more versatile than most other materials making it ideal for applications that go from consumer packing to construction.
The problem is, that none of the commonly used plastics are biodegradable. As a result, they accumulate, rather than decompose, in landfills or the natural environment (1). Just in NSW, Plastic packaging and so-called single-use plastic items make up 60% of all litter. These items take thousands of years to break down and in the process, they are causing great harm to our natural environment and wildlife.
Where do plastics end up?
Figure 1. Global production, use, and fate of polymer resins, synthetic fibers, and additives (1950 to 2015; in million metric tons).
The only way to permanently eliminate plastic waste is by destructive thermal treatment, such as combustion or pyrolysis. Thus, near-permanent contamination of the natural environment with plastic waste is a growing concern with global evidence of plastic debris has been found in all major ocean basins (1) as well as in freshwater systems and land habitats.
Plastic waste is now so ubiquitous in the environment that it has been suggested as a geological indicator of the proposed Anthropocene era (2).
There are essentially three different fates for plastic waste.
- First, it can be recycled or reprocessed into a secondary material (3). Recycling delays, rather than avoids, final disposal, however, contamination and the mixing of polymer types generate secondary plastics of limited or low technical and economic value.
- Second, plastics can be destroyed thermally. Although there are emerging technologies, such as pyrolysis, which extracts fuel from plastic waste, to date, virtually all thermal destruction has been by incineration, with or without energy recovery. The environmental and health impacts of waste incinerators strongly depend on emission control technology, as well as incinerator design and operation.
- Finally, plastics can be discarded and either contained in a managed system, such as sanitary landfills, or left uncontained in open dumps or in the natural environment.
As of 2015, approximately 6300 Mt of plastic waste had been generated, around 9% of which had been recycled, 12% was incinerated, and 79% was accumulated in landfills or the natural environment. (4)
References
- D. K. A. Barnes, F. Galgani, R. C. Thompson, M. Barlaz, Accumulation and fragmentation of plastic debris in global environments. Philos. Trans. R. Soc. B 364, 1985–1998 (2009).
- J. Zalasiewicz, Colin N. Waters, Juliana Ivar do Sul, Patricia L. Corcoran, Anthony D. Barnosky, Alejandro Cearreta, Matt Edgeworth, Agnieszka Gałuszka, Catherine Jeandel, Reinhold Leinfelder, J.R. McNeill, Will Steffen, Colin Summerhayes, Michael Wagreich, Mark Williams, Alexander P. Wolfe, Yasmin Yonan, The geological cycle of plastics and their use as a stratigraphic indicator of the Anthropocene. Anthropocene 13, 4–17 (2016).
- N. H. Mutha, M. Patel, V. Premnath, Plastics material flow analysis for India. Resour. Conserv. Recycl. 47, 222–244 (2006).
- Geyer, Roland, Jenna R. Jambeck, and Kara Lavender Law. “Production, use, and fate of all plastics ever made.” Science advances 3.7 (2017): e1700782.
