MSU study: Dioxin has no adverse
effects on birds, mink in Tittabawassee River flood plain
Updated: Monday, June 20, 2011, 9:56 PM
By Lindsay Knake | The Saginaw News
KOCHVILLE TWP. — A Michigan State University study found several species of
animals living in the Tittabawassee River downstream of Midland were as healthy
as those found elsewhere.
At Monday's Saginaw-Tittabawassee Rivers Contamination Community Advisory Group meeting, MSU Professor Matthew Zwiernik presented findings from the university’s seven-year wildlife study that measured exposure and impact of dioxins and furans on wildlife in Tittabawassee River basin.
Several bird species and American mink that lived near the Tittabawassee River downstream from Midland had higher furan and dioxin exposure in their tissue and diet than animals living along the Pine River and Tittabawassee River upstream of Midland, Zwiernick said.
Animals in all locations showed no differences in individual and population health measurements, he said.
"We were unable to identify with any certainty any furan-associated adverse effects," he said.
Dioxins and furans, chemical byproducts of combustion, are found in sediment along the river system downstream of Midland. They are linked to past emissions by Dow Chemical Co. and other industries.
The $5 million MSU study was funded by Dow and began in fall 2003. The grant from Dow was unrestricted, Zwiernick said. The researchers gave Dow a 30-day notice prior to publishing studies in a peer-reviewed journal.
"They were pretty awesome at keeping their noses out of it," he said.
More than 4,000 professors and students were involved in the study and spent more than 20,000 hours in the field. MSU has released 20 papers in peer-reviewed publications, with seven to 10 more to come, Zwiernick said.
Dow spokeswoman Mary Draves said the study shows the wildlife along the Tittabawassee River is thriving.
Lisa Williams, a U.S. Fish and Wildlife Service contaminants specialist, said she agrees with the main points of the study, but there are still questions regarding wildlife such as fish and juvenile birds that return to the area and reproduce.
"There may still be some risk to some organisms," she said. "Overall the news is very good."
Researchers studied animals that lived and foraged within the flood plain that researchers believed would have high exposures. The study included American mink, great horned owls, eastern bluebirds, great blue herons, American robins, wood ducks, kingfishers, hooded mergansers, tree swallows and house wrens. Researchers collected information about dietary exposure, tissue-based exposure and individual and population health measurements from 6,000 birds and 50 mink in the field.
The MSU researchers collected reference data upstream of Midland from Sanford, the Pine and Chippewa rivers from the Chippewa Nature Center and data downstream of Midland in Freeland Festival Park, Imerman Park and the Shiawassee National Wildlife Refuge.
Zwiernick spoke in-depth about mink, a species whose diet consists of about 50 percent fish. The researchers measured individual health of about 50 trapped minks including body weight, age, nutritional scales and liver weight.
"The mink appeared to be healthy," Zwiernick said.
In stomach content and furan concentrations in livers of mink trapped in the floodplain and reference areas, researchers found the mammals' exposure to dioxin was great enough to be of concern, but they did not find any health differences in mink living in the Tittabawassee River compared to mink living in uncontaminated areas.
In laboratory studies, Zwiernick said, the study found 10 female mink fed a diet with four times the amount of furans in the Tittabawassee River were unaffected in reproduction and individual health. Their kits also were unaffected.
About 10 members of the public attended the meeting, held at Saginaw Valley State University in Kochville Township, along with officials from the Michigan Department of Environmental Quality, U.S. Environmental Protection Agency and the U.S. Fish and Wildlife Service.
Michelle Hurd Riddick, a member of the Bay City-based environmentalist group The Lone Tree Council, said the study will be a significant factor in future decisions in the cleanup process.
However, the study does not answer what is happening to the fish and the people who eat the fish, she said.
Hurd Riddick said she remains concerned that the study did not meet the EPA's ecological risk assessment basic guidelines.
For additional articles like this one, go to the Tittabawassee River Watch web site www.trwnews.net for complete coverage of the Tittabawassee River Dow Chemical dioxin contamination saga. . The Newspaper / Media page of our site contains an extensive archive of media articles dating back to January 2002. The source organization's web site link is listed to the right of the article, visit often for other news in our area. The Newspaper / Media page may be accessed by scrolling down to the bottom of the CONTENTS section and clicking on the Newspaper/Media link.