Pesky plastic: The true harm of microplastics in the oceans

Co-authored by Jessica Perelman

Plastics break down in aquatic environments and get consumed by fish, zooplankton and invertebrates. Credit: Archipelagos Institute.
Plastics break down in aquatic environments and get consumed by fish, zooplankton and invertebrates. Credit: Archipelagos Institute.

Pollution is evidently a major concern when talking about environmental protection in light of human development, but waste that ends up in the oceans is oftentimes overlooked. This is in part because many people do not come face-to-face with it on a daily basis, and the effects caused by contaminating the world’s waterways have not yet reverberated back to affect humans in a substantial way. This “out of sight, out of mind” mentality keeps people from truly understanding the consequences of marine pollution and heedless disposal of waste items. From solid garbage to sewage disposal to fertilizer runoff, more than 80% of waste that ends up in the ocean is generated on land, and one of the major contributors to this mess is plastic. As useful as it is, plastic is a substance that is made to last and does not biodegrade significantly. With numerous recycling and reusable product initiatives circulating today, including water bottles and grocery bag usage to name a few, it seems that strong actions are being taken to minimize the amount of plastic that end up in the environment, which will ultimately help keep it out of the oceans.

There is a certain type of plastic, however, whose damaging effects are not yet widely recognized by the public, and these are microplastics. Microplastics are particles less than five millimeters in size that deteriorate from larger plastic pieces that have entered the oceans. The issue with them has recently come into light due to the use of plastic microbeads in personal care products such as exfoliating shower gel, toothpaste, and makeup, which all wash down the drain. These plastic ingredients can comprise up to 90% of such products, and according to a 2012 survey, 4,360 tons of microbeads were used throughout all European Union countries in that year alone. In light of growing apprehension regarding ocean pollution, and considering the broad range of products from which this pollution originates, it is no shock that tiny plastic particles can accumulate to such quantities as 93-236 thousand tons floating in the oceans as predicted by a recent study in Environmental Research Letters. It is concerning, however, that this amount is 37 times greater than previous estimates because it speaks to just how much more abundant these pesky products are becoming, and how much of an impact they can realistically have on marine wildlife.

A study completed in 2015 from Environmental Science & Technology alarmingly found that eight trillion microbeads were entering aquatic environments throughout the United States every day. This troubling statistic poses the question of how such massive quantities of microplastics are impacting aquatic wildlife, a topic discussed in the recent article, “More Plastic, Fewer Oysters?” via National Geographic’s Ocean Views. The article addresses the harm that consumption of microplastics has had on crustaceans and other filter feeders, and it seems that adding microplastics to the diet of oysters proves that this can have major repercussions on a number of marine organisms. As reiterated from the study by the French Institute for the Exploitation of the Sea, “Oysters that consume microplastics eat more algae and absorb it more efficiently…[their] ability to reproduce is almost halved.” This information is eye opening, laying a platform from which to look deeper into the issue. What is the seriousness of such health implications? Filter feeding organisms are vital components of marine food webs, and their demise could mean severe threats to numerous trophic levels, and perhaps to the humans who rely on these species as a source of food.

Tiny zooplankton like this one readily ingest microplastics in marine habitats. Credit: Matthew Cole, et al., courtesy of the journal "Environmental Science & Technology."
Tiny zooplankton like this one readily ingest microplastics in marine habitats. Credit: Matthew Cole, et al., courtesy of the journal “Environmental Science & Technology.”

Another concern with these foreign particles entering the oceans is that the chemicals comprising microplastics are causing reproductive complications in oysters, which is a very important point to address. Chemical toxins such as DDT and BPA have been found to adhere to microplastic particles according to a Global Microplastics Initiative, which then “enter the food chain when ingested by aquatic life, accumulating in birds, fish, marine mammals and potentially humans.” Could there be further implications of such chemicals to the well being of this broad range of organisms? If accumulation of microplastic toxins can affect reproduction, then it is likely to affect other biological functions within various marine species. Microplastics have already been found inside the bodies of so many organisms, and if attempts to mitigate this problem are going to be successful, it is imperative to understand the full extent of damage that the products are causing.

This past December, President Obama signed a bill banning the use of microbeads in all personal care products. This act is an indication that microplastic pollution is a genuine concern to the highest levels of government and will continue to damage aquatic habitats and waterways if preventative action is not taken immediately. The bill, along with new ideas such as The Ocean Cleanup project, which proposes a method to remove 70,000 metric tons of plastic from the oceans within 10 years, are leading the elimination effort in the right direction. But targeting microplastics will be a much greater endeavor, and eradicating the trillions of tiny particles that have already entered the oceans will be the next big challenge in ocean conservation.

Microbeads are a major source of microplastic pollution and are found in everyday personal care products. Credit: UNEP's Global Programme of Action
Microbeads are a major source of microplastic pollution and are found in everyday personal care products. Credit: UNEP’s Global Programme of Action

About the author: Jessica Perelman is a student at the University of Southern California studying biological sciences. She will be attending veterinary school in the fall and plans to pursue a career in wildlife and conservation veterinary medicine.


  1. Tom Sprehe
    Baltimore, Maryland USA
    July 9, 8:24 pm

    On behalf of many of my solid waste engineering and management colleagues, I would like to express our collective “Whoops!” at this whole marine plastics issue. Here is a problem on the scale of global warming, or bigger, and only now are we waking up to the basic lack of solid waste sanitation in many part of the world (like the whole world). Policy and regulation takes time. The antecedent litter loading on land, coupled with the acceleration of plastic into the economies of developing countries, many without basic SW sanitation, implies an urgency to address the problem. In the US there is a huge opportunity to prevent this problem by litter prevention, or at worse point source interception at tributaries.

    As old William Donald Schaefer used to say, “Do it NOW!”

  2. Jude
    March 15, 11:49 am

    One ‘personal care’ item continually overlooked is the plastic, pearlized, radiant, colored, tampon applicator. It is rags to riches for Proctor & Gamble and Kimberly Clark because of a social silence on a taboo subject.
    At sewage treatment plants, they are separated and ground up to ‘coffee ground size’ (1.5mm) and released directly into rivers and oceans. This ubiquitous item is flushed (and ladies don’t lie) and no thought its given to where it goes. I blame the companies as the ‘Regular’ cardboard model is usually located on bottom shelf out of sight and many young women are not even aware of it.
    Scientists, why has this item never been drawn to public attention?

  3. Kelly
    January 5, 8:34 pm

    Second Paragraph, Second Sentence:
    “Microplastics are particles less than five millimeters in size that deteriorate from larger plastic pieces”

    That probably should read “Five Micrometers”.

    • Carl Safina
      January 5, 9:20 pm

      It’s a non-error. Plastic less than 5mm is considered microplastic. Nanometer-sized is included, but 5mm is the top of the range. I double-checked various resources, including NOAA Marine Debris Program: 

  4. Emad Kamil Hussein
    August 25, 2016, 2:20 pm

    It is so nice article, I am considering this contamination is our responsibility as a researcher to make dramatic solution.
    Regards, Emad

  5. Sofia
    May 17, 2016, 6:04 pm

    I just didnt like the picture on the side that wasnt a part of the article because it was a shark eating a seal ( ew ) :- (. Other than that, it was a good article and I enjoyed reading it.

  6. Dannielle Green
    May 10, 2016, 4:25 am

    Nice article. On the point of phytoplankton, I think this could be a really important impact with cascading effects. Our research also found that microplastics in sediment could reduce the biomass of microphytobenthos (microalgae in sediments):

  7. John Turner
    Massapequa Park, NY
    April 9, 2016, 5:31 pm

    For those readers of this excellent overview living in Suffolk County, New York be aware that the Suffolk County Legislature is currently considering a legislative ban (Introductory Resolution 1207-Spencer) on one-use plastic bags which pose a problem to marine life who ingest it when whole and upon photo-degradation whence the microplastic problem, highlighted in the article, kicks in.

    If the substance of this article upsets you or, better yet, motivates you to do something, a great way to act upon your concern is to communicate your support of the ban to your Suffolk County representative.

  8. Dane Lavery
    Kobe, Japan
    April 6, 2016, 8:10 pm

    For those of you concerned about PCBs in seafood please refer to this link as it might be of interest:

  9. Frank Mancuso
    United States
    April 6, 2016, 2:26 pm

    We need not pause to consider climate it’s way too late. The oceans are vomiting up their suffocating toxic sea life all over the world. It has been recently discovered that phytoplankton is ingesting marine micro plastic. What is generally not known is as marine plastic decomposes it absorbs PCBs spelling the demise of phytoplankton. Phytoplankton supplies over one-half the world’s oxygen supply or every second breath. It is in decline as is ocean oxygen levels and atmospheric oxygen levels. A drop of a couple of percentage points will end it all, some cities are just about there.

    • Carl Safina
      April 6, 2016, 3:28 pm

      Thank you for your comment. You’re right, marine microplastics are harmful not only because they’re not a natural food source, but because they prove toxic to phytoplankton and the animals that consume phytoplankton. You can read more about this issue in another recent piece we wrote on oyster fertility and marine microplastics: