The problem of plastics accumulating in the ocean has been widely documented, with 8 million metric tons (9 million tons) to 11 million metric tons of land-based plastics entering the world's ocean annually, in addition to hundreds of thousands of tons of abandoned plastic fishing gear (at least 640,000 tons), termed "ghost gear", being left in our marine areas each year. Without a large-scale shift in the world's use and management of plastics, especially single use plastic, this will only get worse. In fact, some projections even indicate that there may be more plastic than fish in the ocean by 2050.
In recent years, the issue of tiny plastic particles, termed microplastics (5 mm or less in size), has gotten increasing attention. These microplastics are able to escape wastewater treatment plants and flow with the discharge water straight into our aquatic and marine areas, becoming bioavailable to wildlife from plankton to top tier predators. Some microplastics, like plastic microbeads, were actually designed to be micro sized to help with skin exfoliation, while other plastics, like plastic bottles and containers, start out as larger products but break down overtime into smaller and smaller plastic pieces.
But there’s another microplastic problem that may be even more concerning and harder to address, and it's showing up in our ocean, on our beaches, in the food we eat, in the water drink, and even in the air we breath, called plastic Microfibers. Efforts to combat this problem range from source reduction legislation, such as bans on plastic bags, polystyrene, and plastic cigarette filters; beach cleanups; and even the use of skimmer devices in harbors to much larger proposed cleanup devices in the open ocean.
The definition of microplastics has varied between research papers, so in an effort to standardize the definition of microplastics, the Southern California Coastal Water Research Project (SCCWRP) worked with global experts in the realm of microplastic research and the California State Water Resources Control Board, to officially establish the first agency-adopted definition: "solid polymeric materials to which chemical additives or other substances may
have been added, which are particles which have at least three dimensions that are greater than 1 nanometer and less than 5,000 micrometers. Polymers that are derived in nature that have not been chemically modified (other than by hydrolysis) are excluded". Defining microplastics was the first step in a California state mandate (SB1422) set to establish (1) mandated monitoring of drinking water by 2021, and (2) a statewide management strategy for microplastics in the ocean off California. The next step will be developing standardized testing methods (currently in development) and determining heath-based guidance levels (learn more here).
Almost Everywhere We Look, We Find Microplastics
Beyond shorelines and beaches, researchers have started expanding studies to test for plastic microfibers in other areas, from the tissues and stomaches of marine life to drinking water sources, and the results all continue to point to the same result- plastic microfibers may be the most ubiquitous human-made pollutant. Studies have identified microplastics, including microbeads and microfibers, in:
- Tap Water - In 2017, Dr. Sam Mason worked with OrbMedia to conduct an international study on microplastics in tap water. A total of 159 water samples collected and analyzed from five continents, with 83% of the samples containing microplastics (of those microplastics, 99.7% were microfibers). In the United States, 94% of tap water samples contained plastic.
- Bottled Water - In 2017, Dr. Mason and Orb Media conducted a similar study but focused solely on microplastics in bottled water from all over the world. A total of 259 bottles from 11 brands were purchased from 19 locations in 9 countries, with 93% of bottled water samples containing microplastics. An average of 325 microplastic particles (larger than 6.5 micrometers) were found per liter of bottle water (ranging from 0 to 10,000 particles per liter). Nestle bottled water contained the highest amount of plastic particles.
- Air - In 2014, a study in France tested indoor and outdoor air for plastic microfibers. Indoors, researchers found an average of 3-15 microfibers/cubic meter of air, while outside they found an average of 0.2-0.8 microfibers/cubic meter air. Alarmingly, researchers found evidence of atmospheric deposition with an average of 29-280 plastic particles/square meter/day. In 2019, another study in France confirmed the potential for atmospheric deposition of microplastics, documenting the deposition of 365 microplastics/square meter/day in a remote area of the French Pyreneese Mountains. Microplastics included particles, fibers, and films.
- Salt - In 2018, Incheon National University and Greenpeace East Asia published a study that tested commercial food-grade salt for the presence of microplastics. Of the 39 salt brands tested from 16 countries on six continents, the amount of microplastics found ranged from from 0-1674 plastic particles/kg sea salt (with one outlier of 13,629 plastic particles per kg), 0-148 plastic particles per kg rock salt, and 28-462 microplastics per kg lake salt.
- Honey - In 2013, chemists Gerd and Elisabeth Liebezeit tested 19 honey samples from five countries (Germany, France, Italy, Spain and Mexico) for the presence of "non-pollen particulates", and found that 100% of samples contained microplastics.
- Seafood - A 2015 study found that one in three shellfish, and one in four finfish sampled at a California fish market contained microfibers, and these fish were headed straight for the dinner table. It is estimated that people could be unknowingly ingesting 11,000 microfibers each year from shellfish consumption, and 178 microfibers from eating a single mussel. A 2019 study tested deep-sea larvaceans and pelagic red crabs, and found microplastics in every animal specimen surveyed.
- Beer - In 2014, chemists Gerd and Elisabeth Liebezeit tested 24 German beer brands for plastic particles, with 100% of samples containing microplastics. Microplastics identified included a range of fibers, particles, and granules.
Environmental and Health Risks
More research and data on ingested microplastics is needed, but so far we know that plastics can cause negative human health impacts, including DNA damage, endocrine disruption, cancer, and diabetes. The EPA also found that “in controlled studies, these chemicals have been shown to release from plastic after it is ingested by a variety of marine species,” meaning that whatever consumes the plastic could also absorb the chemicals from the material. Not only are these chemicals harmful to the wildlife that consumes them, but many toxins are also known to bioaccumulate in the body. This means that they work their way up the food chain, eventually reaching humans.
Some direct excerpts from a report by the Marine Debris Program, NOAA, are particularly illuminating :
- Chemical toxicants associated with marine debris (e.g., metals or metal oxides leaching from fish hooks and marine paints, legacy organic pollutants, halogenated compounds, and plasticizers) inevitably enter the body if the debris is ingested.
- Plastics leach out over time, because plastics are essentially solidified oil.
- Microplastics have a high surface area to volume ratio and a large potential to collect toxicants, like pesticides. Because this accumulates on the surface of microplastics over time, microplastics can contain chemicals that we have long prohibited, such as aqueous metals, halogenated persistent organic pollutants (e.g., polychlorinated biphenyls (PCBs)), and others that cause proven harm.
- Finally, although studies on the direct physiological impacts of ingested debris on marine organisms are relatively rare, studies from other research fields (e.g., veterinary science) give an indication of likely effects. For example, female goats fed plastic rope exhibited no clinical signs of disease over fifty days, yet serious damage to the digestive tract was observed on necropsy, including: lesions, increased thickness in the muscle tissue surrounding the plastic, and reduced thickness of mucosal layers.
Because microplastics are insidious in our daily lives, it’s no surprise that microplastics appear in the rain of protected lands in the United States. While their impact on the ecological development of soil and natural life is under current research, the early indications of toxicity that related evidence poses is concerning beyond measure.
So what are the solutions? There appear to be no easy answers except reducing the use plastics at the source. As Kyle Van Houtan, chief scientist at Monterey Bay Aquarium and a co-author of a 2019 study on microplastics in water columns eloquently says “The ubiquitous presence of plastic pollution throughout the water column points to source reduction—making and using less plastic in the first place—as one of the most effective means of solving this issue... It may be virtually impossible to remove existing microplastic from the deep sea.. But when we slow the flow of plastic from land, we can help prevent the increasing accumulation of plastic in our global ocean.”
The issue of microplastics is gaining more attention as new research comes to light. In the U.S., lawsuits under the Clean Water Act have been used as a mechanism to create new standards and best management practices for pre-production plastic pellets, known as nurdles, and bills have been introduced to specifically regulate those pellets under the Clean Water Act.
At the federal level, the Plastic Pellet Free Waters Act was introduced in September 2020. This act would require the EPA to finalize a rule within 60 days to, “Prohibit the discharge of plastic pellets or other pre-production plastic materials from facilities and sources that make, use, package, or transport those materials; and update all existing permits and standards of performance to reflect those prohibitions.”
See these articles to read more about legislative solutions for the most pernicious microplastics — Microfibers and Microbeads.
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- Lau, W.W.Y. & Shiran, Y., et al. 2020. Evaluating scenarios toward zero plastic pollution. Science
- World Animal Protection. 2018. Ghosts beneath the waves: Ghost gear's catastrophic impact on our oceans, and the urgent action needed from industry.
- Rustagi et al. 2011. Public health impacts of plastics: An overview. Indian J Occup Environ Med. 15(3): 100–103
- National Oceanic and Atmospheric Administration Marine Debris Program. 2014. Occurrence and Health Effects of Anthropogenic Debris Ingested by Marine Organisms https://marinedebris.noaa.gov/occurrence-and-health-effects-anthropogenic-debris-ingested-marine-organisms
- Brahney, J. et al. Plastic rain in protected areas of the United States. Science. Vol. 368, No. 6496, pp. 1257-1260.