On Wednesday, the 5 Gyres Institute published a landmark paper that presents the first-ever global estimate of plastic ocean pollution. It is the culmination of six years of data gathered from 24 expeditions undertaken by researchers throughout the world and over 50,000 nautical miles.
Plastic, unlike organic matter, does not biodegrade over known timescales. Instead, it fragments and disperses under the influence of sunlight and other weathering processes. When plastic breaks down into microplastic particles, it can easily pass through water filtration systems and into rivers and oceans. This is to say nothing of the macroscale plastic that washes into harbors after every rain, accumulates on beaches and in the stomachs of marine creatures.
The 5 Gyres Institute is a non-profit organization dedicated to the elimination of plastic waste. In 2012, it shocked the nation when it discovered a huge concentration of microplastic in the Great Lakes, an average of 43,000 plastic particles per square kilometer. Since that time it has worked to raise awareness of the issue, even helping to craft model legislation for a federal ban on cosmetic products containing plastic microbeads.
In its latest paper, published December 10 in the journal PLOS ONE, the Institute reports that there are some 5.25 trillion plastic particles floating in the ocean, with a collective weight of about 269,000 tons.
“When The 5 Gyres Institute formed, we set out to answer a basic question: how much plastic is out there?” says Dr. Marcus Eriksen, Director of Research and co-founder of the 5 Gyres Institute, in a press release. “There was just no data from the Southern Hemisphere, Western Pacific or Eastern Atlantic. After six long years and a wide-reaching collaboration, we have completed the most comprehensive plastic pollution study to date. We’ve found microplastic ocean pollution, in varying concentrations, everywhere in the world.”
This plastic pollution is not limited to the garbage patches formed in the five subtropical ocean gyres (vortices where ocean currents converge and both natural and artificial debris accumulates); it has been measured in remote regions of the planet, in coastal sediments, the circulatory system of mussels, in both Northern and Southern Hemispheres and in the Arctic.
“Our findings show that that the garbage patches in the middle of the five subtropical gyres are not final resting places for floating plastic trash,” Eriksen said. “Unfortunately, the endgame for microplastic is dangerous interaction with entire ocean ecosystems. We should begin to see the garbage patches as shredders, not stagnant repositories.”
The natural UV- and oxidative-fragmenting that affects plastic is exacerbated by ocean waves and the multitude of fish and sea life that graze on it in the gyres. And while the direct environmental impact of plastic is still unknown, the hazard it poses to animals is well-documented. Plastics can absorb toxins such as PCBs, DDT, pesticides, flame retardants, mercury and other organic pollutants. When marine animals mistake microplastic for plankton or other food, they absorb these toxins into their system. When these grazers are eaten by predators, the toxins are passed on, bioaccumulating up the food chain until they end up on your plate.
As Eriksen explains, “The garbage patches could be a frightfully efficient mechanism for corrupting our food chain with toxic microplastics.”
Plastic in all its forms poses another hazard to marine ecosystems, as turdles, nets and floating debris can transport microbes, algae, invertebrates and fish to non-native regions and potentially disrupt existing habitats.
Of note is the fact that 5 Gyres discovered less miscroplastic on the surface than expected. This “suggests removal processes are at play,” the authors of the report write, including UV degradation, ingestion by organisms, decreased buoyancy due to ingestion and then defecation by organisms, and suspension in the water column. The authors acknowledge that fragmentation could be breaking microplastics down into even smaller particles than their nets could catch (smaller than 0.33 mm). Recent studies have also demonstrated some organisms and bacteria may be able to consume and eliminate plastic naturally.
As the authors note, Plastic Europe, a trade organization representing plastic producers and manufacturers, reported 288 million tons of plastic produced globally in 2012. The 268,940 tons of plastic reported in the “All Gyres Paper” is just 0.1 percent of that volume, and though 5 Gyres stresses that its estimate of global weight is in fact “highly conservative,” it does not account for the “potentially massive amount of plastic present on shorelines, on the seabed, suspended in the water column, and within organisms.”
One of the driving goals of 5 Gyres is to make companies responsible for the entire life cycle of their plastic products.
In an email to Planet Experts, Dr. Eriksen wrote, “We don’t need to focus on cleaning the oceans. Most of that 5.25 trillion particles are less than the size of a grain of rice, and they are globally distributed. In time, all of that waste will rest on the sea floor. We REALLY need to focus all efforts on not making more waste.”
Dr. Eriksen will be hosting a Reddit AMA today to discuss the findings of the “All Gyres Paper.”
Update 12.16.14 – The American Chemistry Council, an industry trade association for chemical companies (including plastics makers), reached out to Planet Experts in response to this report. Keith Christman, ACC’s Managing Director of Plastics Markets, speaks about efforts ACC is making to curb plastic pollution in this interview with Planet Experts.