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Tiny pieces of harmful plastic, called microplastics, are prevalent in many rivers that flow into the Great Lakes, according to a study published today in the journal Environmental Science & Technology. Results are also illustrated on a new USGS microplastics website.

Microplastics fall off decomposing bottles and bags, wear off of synthetic clothing and are manufactured into some toothpastes and lotions. Scientists with the U.S. Geological Survey and State University of New York at Fredonia studied 107 water samples collected from 29 Great Lakes tributaries in Minnesota, Wisconsin, Indiana, Michigan, Ohio and New York, and found microplastics in all samples. Together, these 29 tributaries account for approximately 22 percent of the total river water that flows into the Great Lakes.

Microplastics, organic material and other debris in a sample from the Milwaukee River, Milwaukee, Wisconsin. (Austin Baldwin, USGS, Public domain)

“These microplastics, which are harmful to animal and possibly human health, will continue to accumulate in the Great Lakes well into the future,” said Austin Baldwin, a USGS scientist and the lead author of the report. “Our findings can help water managers better understand the types and sources of microplastics in rivers, and which rivers are the most polluted with microplastics.”

Baldwin noted that the study underestimates the actual microplastic concentrations in the rivers because the scientists sampled large microplastics greater than 0.33 millimeters (mm). The majority of microplastics are smaller than 0.1 mm.

Key findings from the study include:

The highest concentration of microplastics was detected in the Huron River at Ann Arbor, Michigan, at 32 particles per cubic meter, or p/m3; High levels of microplastics were also detected in the Buffalo River at Buffalo, New York (31 p/m3), the Ashtabula River near Ashtabula, Ohio (23 p/m3), and the Clinton River near Mt. Clemens, Michigan (21 p/m3); The median concentration of microplastics in all samples was 1.9 p/m3; Urban watersheds had the highest concentrations of microplastics; and Microplastics were also present in streams in forested and agricultural areas.

The scientists found various forms of microplastics in the river samples: fibers, fragments, films, foams, and pellets or beads. Plastic fibers, which come from items such as synthetic clothes, diapers and cigarette butts, were the most common type detected, at 71 percent of the total particles. The least common form found in the river water was microbeads, which are the only form banned by the United States Congress. This ban has not yet taken effect.

“We were surprised by the small amount of plastic beads and high amount of fibers found in the samples,” Baldwin said. “These unexpected findings demonstrate how studies like ours are critical to better understanding the many forms and fates of microplastics in the environment.”

Ingested microplastics can cause digestive and reproductive problems, as well as death, in fish, birds and other animals. Unhealthy additives in the plastic, including flame retardants and antimicrobials, have been associated with cancer and endocrine disruption in humans. Also, pollutants such as pesticides, trace metals and even pathogens can accumulate at high concentrations on microplastic particles.

Scientists have found microplastics nearly everywhere. Aside from rivers, microplastics are also common in lakes and oceans, in freshwater and marine fish, oysters and mussels, and in sediment. They are deposited onto land and water surfaces from the atmosphere.

The Great Lakes Restoration Initiative funded the new study. For more information on USGS microplastics research, please visit the USGS Great Lakes Restoration Initiative website.

USGS scientists Pete Lenaker and Nic Buer collect a microplastic sample at the Manitowoc River, Manitowoc, Wisconsin. (Austin Baldwin, USGS, Public domain) Collecting a microplastics sample using a neuston net, Milwaukee River, Milwaukee, Wisconsin.(Austin Baldwin, USGS, Public domain)

 

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https://www.usgs.gov/news/widespread-plastic-pollution-found-great-lakes-tributaries

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A hibernating little brown bat with a white muzzle typical of white-nose syndrome. (Greg Turner, Pennsylvania Game Commission, public domain)

The bat-killing fungus recently detected for the first time in western North America is genetically similar to strains found in the eastern United States and did not likely originate in Eurasia, according to a study published today in the journal mSphere.  

The findings have implications for resource managers battling the spread of the devastating disease white-nose syndrome (WNS) in North American bats.

Results of the U.S. Geological Survey and USDA Forest Service study provide clues about the origin of this strain of the Pseudogymnoascus destructans fungus, or Pd. This fungus causes WNS and was recently found on a bat near North Bend, Washington, about 1,300 miles from the previous westernmost detection in Nebraska. Because Pd is also present in Eurasia and North Bend is located near an international port, the scientists studied DNA from the Washington fungus to determine if it had roots abroad.

“Although it remains unclear how Pd reached Washington, this finding guides us to look to North America as the source,” said Jonathan Sleeman, director of the USGS National Wildlife Health Center (NWHC), where the Washington bat was confirmed Pd positive. “Now that Pd has been identified in the western U.S., it’s critical to continue working with resource managers to help conserve imperiled bat species, which are worth billions of dollars per year to North American agriculture and forestry.”

In March 2016, a little brown bat found sick near North Bend tested positive for WNS. Following this discovery, the USGS NWHC provided DNA from the fungus on the bat’s skin to a laboratory at the Forest Service’s Northern Research Station (NRS) for genetic analysis.

“The severity and potential ecosystem-level effects of WNS in North America make it one of the most serious wildlife diseases ever recorded,” said Daniel Lindner, a research plant pathologist with the Forest Service’s NRS and a co-author on the study. “We have made a lot of progress in understanding WNS and in monitoring its spread, but more work is needed to determine how disease impacts will vary among bat populations in eastern and western North America.”

Scientists at the Forest Service’s NRS sequenced DNA from multiple strains of Pd, including the fungus cultured from the Washington bat, to determine that it most closely matched fungal strains from eastern North America.

White-nose syndrome was first documented in New York state in 2006 and has rapidly spread westward in North America to neighboring states and into Canada. The disease has killed millions of beneficial, insect-eating bats and threatens several formerly abundant bat species with extinction.

Bats showing signs of infections with Pseudogymnoascus destructans, the fungus that causes white-nose syndrome. (Kim Miller, USGS, public domain)

Based on the current understanding of Pd distribution in North America, scientists cannot determine if the fungus reached Washington from the east by bat movements or through human activities. However, ongoing surveillance efforts coordinated through the multiagency WNS response effort continues to provide insights on the spread of WNS, the impacts of this disease on bat populations and the potential for population recovery.

The national WNS response effort is coordinated by the U.S. Fish and Wildlife Service and involves federal, state and non-governmental organizations, including representatives from the bat conservation and caving communities.

"These results confirm that Pd is capable of movement far across North America. They do not, however, change the importance of taking precautions to reduce the risk of spread by humans,” said Jeremy Coleman, National WNS Coordinator for the U.S. Fish and Wildlife Service. “There's much we don’t know about how Pd will affect populations of western bats, so it is critical to limit spread as much as possible until we can improve survival of susceptible bats."

WNS is not known to pose a threat to humans, pets, livestock or other wildlife.

For more information about WNS, please visit the USGS National Wildlife Health Center and Forest Service’s Northern Research Station websites.

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https://www.usgs.gov/news/deadly-bat-fungus-washington-state-likely-originated-eastern-us

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While exposure was low at most sites, USGS scientists found high concentrations of dioxins and furans in tree swallow eggs from Midland, Michigan, and from the Saginaw River and Bay.​​​​​​​ (Thomas W. Custer, USGS)

Birds at most study sites in the Great Lakes basin were minimally exposed to most environmental contaminants, with the exception of high exposure to dioxins and furans in central Michigan, according to research published today.

Scientists with the U.S. Geological Survey collected tree swallow eggs from 69 sites across the Great Lakes in 2010-2015, including 27 sites designated as Areas of Concern, or AOCs, by the Great Lakes Water Quality Agreement. They tested the eggs for 26 pesticides and other contaminants that could have harmful effects on bird reproduction and development. While exposure was low at most sites, the scientists found high concentrations of dioxins and furans in eggs from Midland, Michigan, and from the Saginaw River and Bay AOC downstream of Midland.

“Our findings are valuable for wildlife managers tasked with protecting birds in the Great Lakes basin, and can be used to assess Beneficial Use Impairments at AOCs across the Great Lakes,” said Christine Custer, a USGS scientist and the lead author of the study.

Scientists tested the eggs for industrial products that can negatively affect animal health, such as polychlorinated biphenyls, or PCBs. The findings showed that:

Only six AOCs exceeded the PCB concentration of two micrograms per gram (mg/g), which is considered elevated;  Mean concentrations of PCBs in the eggs were 10 to over 20 times below the lower limit at which egg hatching begins to be affected, which is 20 mg/g; Other organic contaminants, including p,p'-dichlorodiphenyldichloroethylene, or DDE; mirex; heptachlor; chlordane; and polybrominated diphenyl ethers, were at or below background concentrations, or did not differ between AOCs and non-AOCs. 

Dioxins and chlorinated dibenzo furans are a pollutant that results from high temperature burning, such as incinerators, and during the production of some industrial chemicals such as PCBs and herbicides. The findings specific to Midland and the Saginaw River and Bay AOC included:

The mean concentration of dioxins and furans was highest in Midland eggs at 475 picograms per gram (pg/g). For comparison, the lower limit for hatching effects is 181 pg/g; The mean concentration of dioxins and furans in eggs from a site in the Saginaw River and Bay was 242 pg/g; The other 67 Great Lakes sites had mean dioxin and furan concentrations below 87 pg/g; and High dioxin and furan exposure at these locations confirms earlier reports.

“Remediation efforts are planned, underway or completed by U.S. EPA at numerous AOCs, which should further reduce bird exposure to many of these pollutants,” Custer said.

Over 90 collaborators assisted with the project, including all levels of government, private companies and corporations, non-governmental organizations and private citizens.

The Great Lakes Restoration Initiative and the USGS Contaminant Biology Program funded the study, which was published today in the journal Environmental Toxicology and Chemistry.                                             

For more information on bird health in the Great Lakes region, please visit the USGS Upper Midwest Environmental Sciences Center website.

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https://www.usgs.gov/news/low-levels-contaminants-found-great-lakes-tree-swallow-eggs

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