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Microplastics in our Nation's waterways

Microplastics are the miniscule plastic fragments (smaller than 0.04 inch) that fall off of decomposing plastic bottles and bags, and are intentionally manufactured into some toothpastes and lotions. Scientists have found microplastics nearly everywhere, particularly in lakes, rivers, and aquatic animals.

Where in our waterways are microplastics found?

Studies have found particles in


of freshwater fish1

Fish Picture


particles per serving of commercially-cultured oysters


particles per serving of commercially-cultured mussels2

Oyster Picture

1 particle for every


gallons of Great Lakes tributary water3

On average


particles per square foot of river sediment4

Stream Picture



particles per square mile of Great Lakes water5

Great Lakes Picture

What are the known risks of microplastic pollution?

Microplastics can be harmful to humans, as well as wildlife through:

  • The physical hazards of ingesting plastic particles (fish, birds, and other animals can experience digestive obstruction, impaired reproduction, other adverse biological effects, and even death)
  • The unhealthy additives found in plastic particles (some additives have been associated with cancer and endocrine disruption)
  • The contaminants that accumulate on plastic particles (polychlorinated biphenyls (PCB's), polycyclic aromatic hydrocarbons (PAH's), organochlorine pesticides, trace metals, and even pathogens have been found at high concentrations on microplastics)
Male coaster brook trout.

Can we kick the microplastics habit?

We’re trying. In 2015, the U.S. Congress passed Public Law 114-114 to ban the sale of cosmetics containing plastic microbeads. The ban takes effect in 2018.

The ban addresses microbeads alone, in part because early studies indicated that microbeads were the most common type of microplastic found in aquatic ecosystems. However, those early studies all took place in lakes. Is the same true in rivers?

Microplastics in rivers

U.S. Geological Survey and State University of New York Fredonia scientists sampled rivers flowing into the Great Lakes3 to find out which kinds of microplastics are most commonly found in rivers, and which rivers contain the most microplastics particles.

These scientists found that rivers carry many different kinds of microplastics, and were surprised to learn that plastic microbeads make up only a small fraction of all microplastics.

The USGS scientists found that fibers composed an average of 71% of the total number of microplastics particles found in samples of river water.

Microplastic sample

Hover over the following graph for more information.

How are plastics getting into our rivers?

That turns out to be a tricky question. USGS scientists plotted the microplastics data for the river water samples collected at various locations. Then they compared those data to land-use types found at those same sampling locations to determine if there seemed to be any patterns in the data.

Hover over the data on the graph below for more information.

Though the relationship is modest, it appears that urban watersheds tend to be associated with rivers that have high concentrations of microplastics in the water, which is especially true for plastic fragments, films, and foams. However, scientists were surprised to find no apparent pattern between land use and the most commonly observed microplastic type - fibers.

What's next?

While the ban on plastic microbeads has raised public awareness, the microplastics story is large and complex. Studies like this one conducted by USGS and SUNY Fredonia scientists and funded by the Great Lakes Restoration Initiative are bringing us toward a better understanding of the many forms and fates of microplastics in our Nation's waterways.

Piping Plover


1. Sanchez W, Bender C, Porcher JM. Wild gudgeons (Gobio gobio) from French rivers are contaminated by microplastics: preliminary study and first evidence. Environmental research. 2014 Jan 31;128:98-100 10.1016/j.envres.2013.11.004

2. Van Cauwenberghe L, Janssen CR. Microplastics in bivalves cultured for human consumption. Environmental Pollution. 2014 Oct 31;193:65-70 10.1016/j.envpol.2014.06.010

3. Baldwin, A.; Corsi, S.; Mason, S. Plastic Debris in 29 Great Lakes Tributaries: Relations to Watershed Attributes and Hydrology Environmental Science & Technology. 2016 Sept. 14; 10.1021/acs.est.6b02917

4. Castañeda, R.; Avlijas, S.; Simard, M.;Ricciardi, A. Microplastic pollution in St. Lawrence River sediments. Canadian Journal of Fisheries and Aquatic Sciences 2014, 71(12) 1767-1771. 10.1139/cjfas-2014-0281

5. Eriksen, M.; Mason, S.; Wilson, S.; Box, C.; Zellers, A.; Edwards, W.; Farley, H.; Amato, S. Microplastic pollution in the surface waters of the Laurentian Great Lakes. Mar. Pollut. Bull. 2013, 77 (1-2) 10.1016/j.marpolbul.2013.10.007

6. Rochman, C.M., Browne, M.A., Halpern, B.S., Hentschel, B.T., Hoh, E., Karapanagioti, H.K., Rios-Mendoza, L.M., Takada, H., Teh, S. and Thompson, R.C., Policy: Classify plastic waste as hazardous. Nature. 2013, 494: 169-171 10.1038/494169a