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“The health of the world’s ocean is in serious decline – and human health is suffering as a result,” per the Woods Hole Oceanographic Institution website. Why this somber declaration? Plastics, the most prevalent type of debris found in our oceans, and microplastics, debris less than five millimeters in length and often invisible to the eye.
Two Categories of Culprits
Primary microplastics are designed to be small (e.g., microbeads) and used in commercial products such as cosmetics. Secondary microplastics are formed by the progressive breakdown of larger plastic items, such as polyethylene (plastic bags, bottles), polystyrene (Styrofoam, food containers), polyvinyl chloride (plumbing), and nylon (rope, thread). These items undergo degradation through different methods, including mechanical, heat, UV light, oxidation, and bio-degradation by living organisms such as bacteria. For a good review of this topic read this article.
One striking example of a secondary source of microplastics is the Great Pacific Garbage Patch. Located between California and Hawaii, the Great Pacific Garbage Patch is the largest accumulation of plastic in the world, consisting of 1.8 trillion pieces of plastic that weigh an estimated 80,000 tons. For more information on this topic click here.
Invasion of Our Waterways
The exact number of microplastics entering the ocean is not well known. One study estimated that in the United States alone,100 tons of microplastics enter the oceans annually. According to one review microplastics may enter water sources in a number of ways, including:
deterioration of larger plastic fragments;
direct release of microparticles via urban wastewater treatment;
accidental loss of industrial raw materials during transport or transshipment at sea or into surface waterways;
degraded plastic waste.
In addition, a recent study by the International Water Association concluded that because of a lack of technology to filter microplastics, they may enter the environment through wastewater sludge originated from fertilizer for agriculture.
Prevalence in Marine Life
Microplastics are widespread: from the equator to Arctic sea ice and from shorelines to the deep sea. Indeed, researchers have found that “plastics in the surface waters of the Great Pacific Garbage Patch break down into microplastics that sink down into the deep sea,” as noted on The Ocean Cleanup website. And, according to the Royal Society Open Science, a study of 90 deep-sea crustaceans from six different marine ecosystem trenches found microplastics in 75 percent of the specimens. In 2016, the United Nations Food and Agriculture Organization reported the presence of microplastics in up to 800 species of fish, crustaceans, and mollusks. Photo-degradation plays a role in degrading marine plastics at the surface of the water into microplastics.
The Harm
Once in the environment microplastics can take hundreds or even thousands of years to decompose. During this process, they can cause damage to the environment, often entering the food chain when ingested by zooplankton, small fish, and crustaceans. In fact, microplastics have been discovered throughout the food chain, from plankton to whales. Although the exact mechanisms of toxicity are still being researched, studies have suggested that microplastics can have detrimental effects on organisms through multiple mechanisms, including physical, chemical, and microbial:
microplastic ingestion may cause physical blockage, internal injury, and false satiety leading to severe malnutrition of marine life. They may also cause suffocation by lodging in the gills of air-breathing organisms;
microplastics may act as vectors for harmful microorganisms;
microplastics may release toxic chemicals, “plasticides,” that can be ingested; these toxins can be passed up the food chain to humans.
One study estimated that Chinese shellfish consumers could be exposed to 100,000 microplastics each year. Although microplastics threaten our food, safety studies on direct effects on human health are needed.
What Can We Do?
Although more research is needed to better understand the prevalence of microplastics in the marine environment, their effect on humans, and solutions to the problem, we can all take action to help:
avoid plastic products and use compostable products;
reduce single-use plastics (e.g., straws, plastic utensils);
utilize reusable bags when shopping, not plastic bags;
demand that your elected officials, through phone calls, emails, and mail, take an active role in passing legislation to prohibit the distribution of single-use plastics.
On Long Island, we have multiple organizations that bring awareness to microplastics pollution and work toward solutions. Among them:
Multiple national organizations exist to help bring awareness to the microplastics problem. Among them:
