From microbeads to fibres from fleece and other textiles, microplastics are finding their way into marine ecosystems and entering the food chain.
Authors: Peter Ross and Marie Noel, Ocean Pollution Research Program, Coastal Ocean Research Institute, an Ocean Wise initiative
Reviewer: Leah Bendell, Professor, Biological Science, Faculty of Science, Simon Fraser University
Banner Photo Credit:Ocean Wise
Visible plastic debris has long been recognized as a significant threat to charismatic species such as seabirds, marine mammals, and turtles, but microplastics are now emerging as a concern around the world. Microplastics is a generic term that includes thousands of different human-made polymers. They are defined as plastic particles smaller than five millimetres in size and are categorized in the following simple way:
- Primary microplastics, which include any deliberately made particles including microbeads for toothpaste, personal care products and industrial abrasives, and nurdles, the commercial feedstock of specific polymers then used for manufacturing of plastic products.
- Secondary microplastics, which refer to the particles resulting from the breakdown of larger items, such as beverage and food containers, bags, ropes, and textiles.
Microplastics are increasingly seen as a threat to the marine environment due to their wide distribution, persistence, and risk of adverse health effects in marine life. Despite the never-ending stream of new studies, significant gaps continue to hamper our understanding of source, fate in the environment, and effects of these microplastic particles.
Why is it important?
Microplastics can be found in the environment in the form of small fragments, sheets, fibres, pellets, and granules. Microplastics have been found in sediment and seawater throughout coastal B.C. (Figure 1). Concentrations in seawater were higher near the coast compared with offshore areas, suggesting that human activities on or adjacent to land are resulting in the contamination of marine waters. Fibres were the dominant type of microplastics found in water samples (Figure 2).
It was shown that microplastics are being eaten by species of zooplankton. This highlighted concerns about the vulnerability of ocean food webs and the potential for microplastics to get into Indigenous, commercial, and recreational seafoods as well as into wildlife such as seabirds, seals, and whales. In fact, it was estimated that adult salmon feeding in the Strait of Georgia could be eating as many as 91 microplastic items per day, and humpback whales could be ingesting as many as 300,000 microplastic items per day! Microplastics have been detected in various species of fish as well as filter feeding whale species.
Uptake of microplastics by wild and cultured shellfish was also reported – something that could be partly mitigated by a depuration period (storing live animals in clean water after harvest) for several days before human ingestion. In Europe, it was estimated that the average mollusc consumer could ingest between 1,800 and 11,000 microplastics particles per year! Humans don’t eat the digestive tract of other types of seafoods, so depuration really only make sense for shellfish.
While studies on the effects of microplastics on living organisms that ingest them are limited, it is suggested that, once ingested, potential negative impacts include false satiation, blockage of internal organs, transfer between tissues, and possible accumulation of toxins.
What is the current status?
Microplastic pollution represents a recent topic of scientific and public interest, such that little trend information on contamination of the ocean environment exists. However, the escalating global production and use of plastics, of which only five percent is recycled, provides a stark indication of likely trends in the environment (Figure 3).
What is being done?
At the national level, regulations are in place in some countries for one particular type of microplastics – microbeads – found mostly in personal care products. Prior to a ban, it was estimated that the United States was releasing enough microbeads to cover more than 300 tennis courts daily. Now microbeads are banned in the United States, the United Kingdom and Canada.
As fibres have been shown to be the main type of microplastics found in the ocean, the Ocean Pollution Research Program (at the Coastal Ocean Research Institute, an Ocean Wise initiative) is teaming up with Mountain Equipment Coop (MEC), Patagonia, Arc’teryx, Recreational Equipment Inc. (REI) and MetroVancouver to lead some research on microfibres and shed light on the source, transport, and fate of this particular type of microplastics.
Ocean Wise is conducting various research projects to increase our understanding of the sources of microplastics in the marine environment, the efficiency of our wastewater treatment plants for removing microplastics, as well as the effects of microplastics on ocean creatures. This will help develop efficient and local-specific mitigation measures preventing further increase of plastic pollution.
What can you do?
Individual and Organization Actions:
- Be plastic wise and reduce your plastic waste, for example avoid single-use plastic like plastic bags and plastic cups. Educate yourself and become a leader by promoting your knowledge in your community (Figure 4)
- Install filtering devices on your washing machines to trap fibres being released from your clothes during the wash.
- Choose natural over synthetic textiles.
- Participate in shoreline cleanups to reduce the amount of garbage and plastics circulating in the marine environment.
Government Actions and Policy:
- Ban single-use plastics such as plastic bags, coffee cups, drinking cups, cutlery, Styrofoam, straws, and takeout containers.
- Adopt zero-waste goals and enforce regulations.
- Support microplastics-related research.
- Support educational programs for all ages.
- Support development of recycling technologies and local facilities.
- Enforce recycling regulations.