Residents question Lake Iroquois herbicide proposal

Observer file photo  Last summer, milfoil was removed from Lake Iroquois manually. This summer, a chemical herbicide treatment is planned.
Observer file photo
Last summer, milfoil was removed from Lake Iroquois manually. This summer, a chemical herbicide treatment is planned.

DEC grants $41K for ‘aquatic nuisance control’

By Jason Starr

Observer staff

This summer will mark the biggest investment yet in Lake Iroquois’ ongoing battle with invasive Eurasian milfoil. But the remedy chosen by the Lake Iroquois Association advocacy group involves the application of an herbicide that several shoreline residents wary.

The Vermont Department of Environmental Conservation announced the grant award on March 31. The money comes from the state’s Aquatic Nuisance Control program.

Last summer, the Lake Iroquois Association tried manual removal of milfoil from the lake bottom using professional divers, but the problem persisted.

“In the last few years, the milfoil infestation has gotten significantly worse,” said Lake Iroquois Association board member Jaime Carroll. “It’s affecting people’s ability to swim and paddle, and it’s out-competing the native plants. We are seeing a reduction in species diversification.”

The Department of Environmental Conservation issued tentative approval in March for application of the herbicide SePro Sonar. The product’s label lists the active ingredient as fluridone and says the product is “harmful if swallowed, absorbed through skin or inhaled. Avoid … contact with skin, eyes or clothing.”

For a lake that borders three towns, is a source of drinking water for shoreline residents and a popular swimming spot, these product qualities are cause for concern, several residents have said in comments submitted to the DEC.

Vermont Lake and Shoreland Permit Analyst Misha Cetnar provided an anonymous list of resident comments to Williston Town Manager Rick McGuire on April 4 — about halfway through the 30-day comment period on the DEC’s tentative approval.

The volume of comments prompted McGuire and his counterpart in Hinesburg to request a public information meeting on the issue. That meeting is scheduled for 6-8 p.m. May 4 at Hinesburg Town Hall.

The comments describe the herbicide as unproven and risky and question whether sufficient oversight will be provided for the contractor hired to apply it to the lake.

“This chemical has never been tested for carcinogenic and other health effects,” one resident wrote to the DEC. “Declaring it to be safe is wrong. There is not enough data to show that it is safe since the necessary testing has never been done.”

“Are we willing to take that risk,” asked another commenter, “especially in children who love to swim and play in the lake and inevitably will drink or aspirate some of the water?”

Another resident wrote:” “We take our water from the lake for drinking and bathing. We know that other residents around the lake use the water for the same purposes. How can we be assured that the contractor hired to apply the Sonar knows about each water source and to stay a safe distance away from it? The lake is not that big.”

Carroll, who researched several milfoil removal options for the Lake Iroquois Association, maintains that the chemical treatment is a good option. It’s been researched and proven successful in other Vermont bodies of water, he said.

“We are certainly cautious with any use of chemicals,” Carroll said, noting that the chemical treatment would be a first for Lake Iroquois. “We will treat it and test for it. It doesn’t persist in the environment and it doesn’t bio-accumulate.”

If the program is approved, it will account for the majority of the $41,000 grant, McGuire said. The grant will also help pay for the association’s summer greeter program (see sidebar). The program staffs the lake’s primary boat launch with greeters who check boats and trailers for invasive species and educate visitors about the milfoil problem.

Boats are the primary vehicle carrying milfoil from one body of water to another.

Greeters will also employ a boat pressure washer for the first time this season to remove any invasives from boat hulls before they enter the lake.