TRAVERSE CITY — A black, arsenic-tainted muck coated portions of Boardman River bottom after an October breech at Brown Bridge Dam and resulting flood, and one riverfront resident worries the substance might prove harmful to humans.
Dave Downer lives with his wife Sally on land that straddles the Boardman. The Downers’ property sustained only minor damage after an Oct. 6 flood caused by construction crews as they prepared to empty an upstream pond, a step in a massive, multi-million dollar project to remove dams upstream from Boardman Lake and return the river to a more natural state.
But the Downers worried about changes they saw in the waterway, including the post-flood appearance of dense silt.
“This is a river where you could always see the bottom,” Sally Downer said. “It turned black. It smelled.”
The silt has cleared up some, but in mid-December Sally and a friend noticed another change as they kayaked along the river. They found large deposits of black muck — Dave Downer said it resembles tar — settled on river bottom.
In January, Dave Downer collected a sample of the dark, viscous material and sent it to Traverse City-based SOS Analytical lab for testing.
Testing results showed levels of arsenic in the muck that exceed the Michigan Department of Environmental Quality’s cleanup criteria, he said, findings that trouble the Downers.
“If that’s the case, we have lost a tremendous recreational asset,” Dave Downer said. “Hundreds and hundreds of people come down this river every year. When my kids come here, and my grand kids, I don’t know if I’m going to let them swim in the river.”
Dave Downer recently shared results of the lab test with fellow members of the Brown Bridge Advisory Committee, a group that works with local government officials and other agencies on river-related matters. He said he had the muck tested as a private citizen.
Steve Largent works for the Grand Traverse Conservation District. The district serves as support staff to the Brown Bridge advisory group. Largent is also a non-voting member of the Boardman River Dams Implementation Team, the public-private group that oversees the dam removal project. Largent reserved judgment on Downer’s tainted muck findings.
“I wouldn’t raise a red flag right now,” he said.
Dams naturally trap large levels of sediment. Project officials expected some of that sediment to move downstream during the removal process, he said. He said it’s difficult to determine if the dam breech and flooding swept more sediment into the stream than expected.
The Downers said they don’t care to point fingers or pin responsibility for the black muck’s appearance.
“It’s not to criticize anybody or anything,” Sally Downer said. “It’s just to say, ‘it’s here and let’s take care of it before this summer.’”
Ben Bifoss, Traverse City manager and a member of the dam implementation team, said a cleanup plan is being devised with AMEC, the engineering firm hired to remove Brown Bridge dam. The plan will be submitted to the DEQ.
Bifoss doesn’t know what the plan will entail, but he said residents shouldn’t be concerned, based on information he’s seen.
Brian Jankowski, a district supervisor for the DEQ in Cadillac, said officials are assessing where sediment was deposited in the Boardman and where it needs to be removed.
He would not comment further on that process, or on Dave Downer’s test results.
“There’s just too many entanglements from an enforcement and a litigation standpoint for me to comment at this time,” Jankowski said.
Arsenic is a naturally occurring element found in relatively low levels in most soil.
Arsenic compounds commonly were used as pesticides in the first half of the 20th century, but the federal government began to restrict some of those pesticides in the second half of the century. The federal Occupational Safety and Health Administration classified inorganic arsenic as a carcinogen in 1978. The Environmental Protection Agency also listed inorganic arsenic as carcinogenic in 1980.
Ingestion and inhalation are the most common and serious forms of exposure to arsenic.
Ingesting high levels of arsenic can be lethal. Ingesting or inhaling lower levels of the element can lead to nausea, vomiting, a darkening of the skin and the appearance of small warts, according to the Agency for Toxic Substances and Disease Registry.
Skin contact with inorganic arsenic can cause redness and swelling.
Sally Downer has spent her entire life along the shores of the Boardman. Her family acquired the property where she and Dave live in the 1940s, and Sally said she’s developed a deep connection with the river.
“It becomes a part of your soul,” she said. “You go through a grieving process when something like this happens.”