Hudson River mink populations are declining because of PCB contamination from General Electric's past practice of dumping the chemicals into the river, according to a new federal study.
The U.S. Fish & Wildlife Service said the cat-size semi-aquatic mammals, known for their soft fur, are exposed to high levels of PCBs, or polychlorinated biphenyls, because of their diet of fish and small animals, and because they live in the river.
The dangers to mink are documented in a new peer-reviewed, multi-year study commissioned by the Hudson River Natural Resource Trustees, who are documenting the environmental impacts of the PCB dumping from GE plants in Hudson Falls and Fort Edward between 1946 and 1977.
The Natural Resource Trustees, which also include the state Department of Environmental Conservation, operate separately from the Environmental Protection Agency-supervised river cleanup, in which GE spent $1.7 billion to remove PCBs from the river between Hudson Falls and Troy. Many environmentalists contend more dredging is needed, a view shared by the DEC.
The debate about whether GE should be required to do more cleanup continues, with GE officials contending they've met all EPA mandates. The EPA is reviewing whether the dredging work done between 2009 and 2015 was successful.
"The DEC remains committed to a fully protective cleanup of the Hudson River. The job is far from done," said DEC officials, in a prepared statement issued Friday. "The study released [Thursday] is further evidence of GE’s failure to complete the cleanup and EPA’s years of failed oversight. New York will continue to use all legal tools to vigorously challenge the EPA and hold GE accountable for the costs of a full cleanup. The Hudson River and its communities must not be left to suffer the consequences of pollution for generations to come."
Mink have historically inhabited Capital Region rivers and streams. Four centuries ago, the trapping of fur-bearing mammals like beaver and mink was a prime reason Europeans settled in the Capital Region, and the species resonates in the public's mind with an era in which mink coats were synonymous with high social fashion.
In the new study, scat-detecting dogs helped researchers find and collect mink excrement. Individual mink in the region were identified through DNA, and experts used that information to estimate population density, ultimately concluding that approximately 40 percent fewer mink live along the Hudson River than in the Mohawk River. The primary distinction between these two rivers, according to the trustees, is the Hudson River’s PCB contamination.
“Decades of PCB contamination continue to have severe and adverse effects on entire populations of animals, such as mink, in the Hudson River,” said Kathryn Jahn, the Department of the Interior’s case manager for the Hudson River Natural Resource Damage Assessment. “Habitat and wildlife restoration, or land protection, by General Electric to help address this problem could begin at any time.”
The study of mink populations was published in June 2018 in Nature’s Scientific Reports research journal, with on-river research done in 2013 and 2014. Fish & Wildlife said the Mohawk River was chosen for its lower ambient PCB levels and similar habitat features, making it a viable comparison for the study.
In the Hudson River study area, a total of 108 mink were detected, compared to 208 in the Mohawk River study area. Mink density estimates were 1.12 mink per square kilometer in 2013 and 1.18 mink per square kilometer in 2014 in the Hudson, and 1.84 mink per square kilometer in 2013 and 1.97 mink per square kilometer in 2014 in the Mohawk River study area.
“PCBs have demonstrable detrimental effects on aquatic ecosystems, including mink, and these effects are likely to be profound and long-lasting, manifesting as population-level impacts,” wrote the authors, who are affiliated with the University of Massachusetts, Amherst; U.S. Geological Survey; and state Department of Environmental Conservation.
Previous studies have shown Hudson River mink have higher levels of PCBs in their systems than other mink, and that captive mink fed a diet that includes PCB-contaminated fish suffer ill effects and die younger than other minks. High PCB levels have also been found in Hudson snapping turtles, bull frogs and birds.
The trustees are documenting natural resource injuries from the PCB contamination, with the goal of spurring GE to future action aimed at restoring the environment. Fish & Wildlife spokeswoman Meagan Racey said the trustees expect GE to reimburse the cost of the studies, through negotiations.
In a statement, GE said PCB levels in the river have declined since the dredging project ended three years ago, and the river remains home to "robust and thriving" wildlife populations.
"The Hudson River is an environmental success story," said Mark Behan, of Behan Communications in Albany, a firm hired by GE for its public relations efforts regarding the dredging. "A limited study of comparative mink scat does nothing to diminish the historic Hudson River cleanup that reduced PCB levels of sediment by 92 percent, or the ongoing environmental recovery of the river as a whole," Behan continued. "Indeed, all signs point to continued progress."
The Natural Resource trustees include the National Oceanic and Atmospheric Administration, U.S. Fish & Wildlife, and DEC.