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Tiny plastics causing big problems in our oceans


There is growing concern over the problem of plastic pollution in the marine environment. Over 5.25 trillion pieces of plastic, weighing 269,000 tons, are believed to be spread throughout the earth’s oceans. Plastics decay slowly and often travel far from their origin in ocean currents, leading to accumulation in the marine environment and even the remote oceans around Antarctica, which contain approximately 50,000 plastic particles per square kilometre. Larger plastic items tend to degrade into smaller plastics and can become ‘microplastics’ (generally classified as plastics smaller than 5mm in size). Primary microplastics, including microbeads, are manufactured deliberately.

But what are microbeads? And why are they so bad?

Microbeads are a primary microplastic used in personal care products including exfoliating scrubs and toothpastes. They are also used as an abrasive in products such as cleaning agents. Microbeads and other microplastics (such as fibres coming off clothes) find their way into fresh and marine water systems as they are not captured by wastewater and sewage treatment systems. While larger plastics often float on the ocean, concentrating in the centre of gyres (circular oceanic currents) and shallow ocean sediment, microplastics settle in greater concentrations on deep ocean sediment. This means microplastics may affect deep sea organisms as well as marine life in shallower waters.

Marine species as diverse as turtles, birds and whales can be harmed when they ingest, or become entangled in, plastics. Consumption can occur accidentally or by purposely eating what is mistaken for prey. As ingested plastic can build up in the stomach, the amount of food that an individual can eat and absorb is limited, reducing fitness. It can also cause internal injury and death through intestinal tract blockage in many species. Species higher up the food chain can also ingest plastic by eating individuals who have accumulated plastic.

Marine vertebrates can absorb the toxins in ingested plastics into their body. Studies have shown that polychlorinated biphenyls (PCBs) from plastic in the stomach can be absorbed into tissue of seabirds and sea turtles. Fish can also bioaccumulate toxins from plastics, such as polycyclic aromatic hydrocarbons, PCBs and polybrominated diphenyl ethers. These endocrine-disrupting toxins can change hormone levels, increase rates of some diseases, and cause reproductive problems and death. They can be harmful to marine species even at very low levels.

Could this affect human health?

Even as early as the 1970s, before global plastic production increased dramatically, a study found over half the fish species examined for plastic ingestion contained polystyrene particles. In some species, up to one third of the individuals sampled had ingested plastic. Recently, plastic has been found in fish and molluscs (such as mussels and oysters) sold for human consumption. For example, a sample of fish bought at an Indonesian market showed that 55% of species and 28% of individuals had plastic in their gastrointestinal tract. Cleaning molluscs before eating does not remove all the particles; they can remain in the tissue, circulatory system and/or digestive tract.

Humans can ingest microplastics from seafood. One study estimated that approximately 90 plastic particles are ingested from an average 250g serving of mussels and 50 particles from an average serving of six oysters. The number of particles will be affected by the concentration of microplastics present in the marine area. It is possible that ingested plastic particles may move from the gastrointestinal tract to other parts of the body. This depends partly on the size of the particles, with microscopic particles able to move from the gut in humans. Humans could be exposed to toxins contained in plastics by ingesting the plastics in seafood or eating seafood that has raised levels of toxins.

What is being done?

In December 2015, state, territory and federal ministers announced a voluntary removal of microbeads from personal care, cosmetic and cleaning products sold in Australia by July 2018. Strengthening this, the federal Environment Minister, Greg Hunt, announced in February this year that he will implement a legal ban by 1 July 2017 if the voluntary phase out is not effective.

Other countries, including the United States and Canada, have already moved to ban personal care products containing microbeads. Some cosmetic manufacturers are voluntarily phasing out microbeads. All major Australian supermarket chains have reportedly committed to banning microbeads from their own-brand personal care products by the end of 2017.

Greg Hunt has proposed using Australia’s product stewardship legislation to ban microbeads. The Product Stewardship Act 2011 (Cth) aims to reduce the environmental and health impacts of products throughout their lifecycle. The Environment Minister publishes an annual list of products being considered for product stewardship arrangements and must give 12 months’ notice before regulating a particular product. The most recent list includes products containing plastic microbeads.

However, a Senate Committee recently recommended that the Australia Government immediately ban personal care products containing microbeads, based on evidence of the environmental damage caused by microbeads.

Mechanisms to enact an immediate ban on microbeads include amending the Cosmetics Standard 2007, made under the Industrial Chemicals (Notification and Assessment) Act 1989 (Cth). The Standard currently sets out requirements for products like sunscreens and could be amended to specify that certain products, such as facial cleansers and toothpaste, must not contain microbeads. It is an offence to import or manufacture a product that does not meet the Standard. Since most products containing microbeads are likely to be imported from overseas, they could also be listed under the Customs (Prohibited Imports) Regulations 1956. These regulations prohibit the importation of a wide range of goods and chemicals into Australia, but would not prevent Australian manufacture of products containing microbeads.

Numerous options exist to ban products containing microbeads in Australia. However, microbeads are only one source of microplastic pollution. Given the consequences of microplastics in the ocean, including their possible effects on marine ecosystems, marine species and human health, solutions to deal with other sources of microplastics, including larger plastics, are also needed. Such solutions will require a cooperative approach from all levels of government in Australia as well as industry.

 

Co-authored by Sophie Power and Emily Hanna