With the global population expanding with each generation, human beings have increased the pressures placed upon the marine environment with this pressure often taking the form of marine pollution. Marine pollution is a major problem, particularly for coastal areas, and this is having a knock-on effect for the communities reliant upon them. One key area of concern in coastal areas is that of marine litter and its biggest contributor, plastics.
It has been shown that 10% of all plastics produced end up in the marine environment (Thompson 2006). Not only do plastics pose considerable dangers to aquatic life due to entanglement and ingestion (which can lead to fatality), it is also extremely slow to breakdown and so persists in the ocean years after it has entered the water. If global plastic production was to halt now, the plastic in the world’s oceans would not disappear completely for at least 1,000 years (van Sebille et al. 2012). From an Irish perspective, marine litter is a major issue with 57% of all coastal waters containing varying degrees of marine litter, with almost half of this being made up of plastics (Moriarty et al. 2016).
Floating plastics tend to aggregate within circulating ocean currents, also known as gyres, with the largest being found in the Pacific Ocean (Kaiser, 2010). This “garbage patch” is the largest of the 6 located in the oceans around in the world, including the Atlantic. It is thought that there is more plastic located in these patches than there is marine life (van Sebille et al., 2012), with the majority of the plastics, comprising of smaller particles known as microplastics.
So what are Microplastics?
Microplastics are smaller pieces of plastic (approx. 5mm in length), that are produced when larger plastic debris are broken down by UV radiation. Microplastics also occur within the marine environment in the form of microbeads. Microbeads are very small pieces of manufactured polyethylene (PE) plastic (see also: polypropylene (PP), polyethylene terephthalate (PET), polymethyl methacrylate (PMMA) and polytetrafluoroethylene (PTFE)) that are utilised in everyday beauty and hygiene products (toothpaste, soap exfoliators). These micrometer-sized particles are too small for water treatment facilities to filter and process and as such they have entered our waters and now outnumber larger debris significantly (Browne et al.).
What are the effects?
As UV radiation degrades these plastics to microscopic sizes, many of their toxic material components enter the marine food chain (Teuten et al., 2009) which in turn can impact on ecophysiological functions performed by marine organisms (Browne et al. 2013, 2390). In a recent study, Browne et al. (2013, 2391) have shown for example that microplastics ingested by lugworms ‘accumulated large enough concentrations of pollutants or additives to reduce survival, feeding, immunity, and antioxidant capacity’. This has greater implications for marine organisms as a whole. The larger surface area of these particles also causes the aggregation of emerging contaminants, which can also enter the food chain (Lusher et al., 2015) resulting in knock on effects to the physical health of people in coastal areas, and inland.
Good News for our Environment?
These numbers are rather alarming and the effects warrant a great degree of concern and action. Some positive steps have however been taken to combat the polluting of our marine environment with plastics through education, policy making and activism. Positive moves have for example been made by the USA and the UK in tackling the production and use of microbeads in cosmetics and other body care products. The USA were the first to initiate a ban on microbeads in commercial products in 2015 when it enacted federal legislation on the matter with the Microbead-Free Waters Act being passed by N.Y. State Assembly by a vote of 108 to 0. They have pledged to fulfill this ban by mid 2017. In the UK many companies had begun phasing out the use of microbeads amid growing concerns from the public and conservationists with surveys by the Cosmetic, Toiletry & Perfumery Association showing a 70% reduction in use. However MPs have begun the process to ban microbeads from healthcare products and have guaranteed a full ban by the end of 2017. This is an important development in the conservation of our marine environment and it is hoped that all EU member states will follow suit in order to protect our collective coastal environments.
Browne, M. A., Niven, S.J., Galloway, T.S., Rowland, S. J. & Thompson, R.C. (2013) Microplastic Moves Pollutants and Additives to Worms, Reducing Functions Linked to Health and Biodiversity.
Darwin, J. (2008) Poison in the Well: Radioactive Waste in the Oceans at the Dawn of the Nuclear Age. Rutgers University Press.
Kaiser, J. (2010) The dirt on ocean garbage patches. Science (New York, N.Y.), 328(June), 1506.
Lusher, A. L., Hernandez-Milian, G., O’Brien, J., Berrow, S., O’Connor, I., & Officer, R. (2015) Microplastic and macroplastic ingestion by a deep diving, oceanic cetacean: The True’s beaked whale Mesoplodon mirus. Environmental Pollution, 199, 185–191.
Moriarty, M., Pedreschi, D., Stokes, D., Dransfeld, L., & Reid, D. G. (2016). Spatial and temporal analysis of litter in the Celtic Sea from Groundfish Survey data: Lessons for monitoring. Marine Pollution Bulletin, 103(1-2), 195–205.
Teuten, E. L., Saquing, J. M., Knappe, D. R. U., Barlaz, M. A., Jonsson, S., Björn, A., Takada, H. (2009) Transport and release of chemicals from plastics to the environment and to wildlife. Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences, 364(1526), 2027–45.
van Sebille, E., England, M. H., & Froyland, G. (2012). Origin, dynamics and evolution of ocean garbage patches from observed surface drifters. Environmental Research Letters, 7, 044040.