Alarms raised about herbicide runoff as planting season nears

A cornfield in Vermont. File photo by Roger Crowley/VTDigger
Over the next three months corn farmers around the state will begin applying one of the most common soil and surface-water contaminants in the United States, the herbicide atrazine, and environmental advocates say it will cause serious harm to Vermont’s aquatic life.

Researchers believe this chemical caused or contributed to Missisquoi Bay’s intersex smallmouth bass. More than half the male fish in Missisquoi Bay bear eggs, and atrazine is known to cause abnormal feminization of various animals.

A recent study prepared for the Lake Champlain Basin Program found atrazine levels in streams feeding Missisquoi Bay and St. Albans Bay that are high enough to be toxic to plant life, but officials at the Agency of Agriculture, Food and Markets say they’re not worried.

Mississquoi Bay from the Tyler Place.
Missisquoi Bay. File photo by Cindy Hill
Atrazine will be applied to cornfields around the state through June, but it’s found in Vermont streams only when storms cause rainwater runoff from fields where it’s been applied, said Cary Giguere, the agency’s agrichemical program manager. The agency doesn’t monitor atrazine levels on days between rainstorms, Giguere said, but previous monitoring has shown that concentrations of the chemical decrease dramatically once the rain stops, often to the point of being undetectable.

Atrazine was observed in Jewett Brook, which drains into St. Albans Bay, at levels many times what the Environmental Protection Agency says is toxic to plants.

The study found levels of up to 26 parts per billion in 2015, according to the report.

The chemical is acutely toxic to nonvascular plants, like algae, at levels below 1 part per billion, according to the EPA. It’s acutely toxic to vascular plants, such as duckweed, at levels below 5 parts per billion. The EPA defines “acute” in this instance as relating to exposures of fewer than 10 days.

In the worst-case scenario, Giguere said, this means some duckweed and algae might die off. But there’s already far too much algae in St. Albans Bay and Missisquoi Bay, where the atrazine levels are the highest, he said. Blue-green algae blooms that occur annually in these areas are primarily because of phosphorus in fertilizer farmers use that runs off into nearby surface waters.

In other words, Giguere said of atrazine: “It’s not a concern yet.”

However, it should be, said James Ehlers, executive director of the advocacy group Lake Champlain International.

Giguere is right that atrazine will kill off algae and duckweed, Ehlers said, but he’s wrong to think that shouldn’t be a concern.

“His remarks are everything that’s wrong with the Agency of Agriculture’s attitude toward the natural world,” Ehlers said.

Ehlers said Giguere was confusing algae with bacteria.

“Blue-green algae is not algae, it’s bacteria,” Ehlers said. But green algae, he said, is a key component of Vermont’s aquatic ecosystems.

Several scientists contacted for this story said they couldn’t provide any definite conclusions on the effects of atrazine upon blue-green algae, or cyanobacteria. A 2006 study from the University of Nebraska found that, as previous studies had found, “green algae appear very sensitive to atrazine, while cyanobacteria and diatoms appear more tolerant.”

“The Agency of Ag continues to flash their ignorance and wear it as if it’s a badge of honor,” Ehlers said. “That the Agency of Agriculture would be unaware of the distinction (between cyanobacteria and algae) is extremely unsettling.”

It’s not trivial, either, that atrazine is found in Jewett Brook at levels five times what’s needed to kill off plants like duckweed, Ehlers said.

Blue-green algae bloom
A blue-green algae bloom in St. Albans Bay. Photo courtesy of Gould Susslin
“Algae is part of the food chain, and duckweed is part of the habitat” for wildlife, he said.

Duckweed is a plant commonly found in slow-moving water and in wetlands. Both duckweed and green algae are effective enough at removing phosphorus and other contaminants from water that they’re used to treat sewage. Phosphorus is the key pollutant in Lake Champlain that drives toxic blue-green algae — or cyanobacteria — blooms.

A further concern with the herbicide has to do with when its concentrations are highest in Vermont waterways, Ehlers said. Atrazine is applied when many fish and amphibian species are hatching, Ehlers said, and are most susceptible to developing intersex traits.

Giguere has said atrazine is not associated with the fact that 60 percent of Missisquoi Bay’s male smallmouth bass bear female sex characteristics.

Giguere said atrazine is among the most highly regulated substances in Vermont. A license is required to buy atrazine, he said, and four Agency of Agriculture staffers monitor farmers and applicators to ensure this and other pesticides are used according to manufacturers’ instructions.

But the Lake Champlain Basin Program report, written by Giguere’s former employee, retired Agency of Agriculture chemist Nat Shambaugh, states that there are no regulatory limits governing what concentrations of atrazine and other pesticides are allowed in surface waters.

In testimony to legislators in April, Shambaugh said the Agency of Agriculture “has no ongoing long-term surface water monitoring program for pesticides, (and) surface water monitoring for corn herbicides such as atrazine is being de-emphasized.”

That’s a problem, said Jon Groveman, Vermont Natural Resources Council’s policy and water programs director.

Atrazine is banned in Europe, he said. And just because farmers in the United States use the chemical according to the manufacturers’ instructions, he said, that doesn’t mean atrazine isn’t reaching unsafe levels in Vermont waterways.

“Whatever the labels are saying is not stringent enough to protect atrazine from getting out into the environment,” Groveman said. “From our perspective, this is a dangerous poison that’s not being controlled sufficiently.”

Groveman and Ehlers have both asked the Agency of Agriculture to exercise its authority to restrict use of atrazine, he said, “but the Agency of Agriculture has declined” to do so.

“We’re working on another request, or maybe a petition,” Groveman said.

Shambaugh could not be reached for comment.

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  • Peter Allan Burmeister

    Faces change at the top of the Agency of Agriculture’s organizational chart, but its policies that allow conventional dairy farms to defile the environment, while producing milk that no one wants or needs, remain the same, no matter who is Governor, no matter who is Ag Secretary. Surplus milk gets dumped into manure pits almost daily, while herbicide and pesticide runoff continually flows into streams and lakes. And the farm lobby seeks government subsidies to shore up the price of this worthless commodity. What is wrong with this bizarre picture? When will governmental authorities wake up to the fact that conventional dairy, far from being an “economic engine” for Vermont is actually a drain on our resources, both financial and natural? In this greenest of states, it is a tragic catastrophe that we allow industrial pollution to go unchecked, unregulated and ignored especially when the product that causes it has virtually no economic value.

  • Jason Brisson

    Lake Champlain is under assault by herbicides, manure runoff, and municipal sewage…our lake, our water, our future.
    Humans create the problems, humans need to solve the problems too.

    • Christopher Daniels

      Can’t put it much better than that.

  • george boomhower

    Again, the picture depicting a blue green algae bloom in St Albans bay was 2015 or before. Last year, 2016, was a nearly pristene water year for St Albans Bay, the Georgia Shore, Lake Carmi and, I understand, maybe even the Misissquoi Bay, I didn’t observe that one. The reasons? Less snow melt runoff, lighter spring rains, 15 years after the double flood years of 2011 and hopefully less corn planted. This last would be encouraging. Less corn???
    George Boomhower. Essex.

  • Kai Mikkel Førlie

    Thanks Dept. Of Ag for protecting the residents and environment of Vermont from the threat of persistent groundwater contamination by an industrial toxic that’s banned in Europe! Oh, wait…. 🙁

  • Patty Smith

    Leaders in Montpelier need to take a wholistic, multidisciplinary, approach to natural resources management, agricultural planning and economic development. Conventional dairy farming is a disaster for farmers and our shared environment. Regions that have banned the use of agrochemicals have seen tremendous economic growth, while improving local quality of life and helping to clean our toxic world. Living soil also sequesters CO2–not so with chem-treated dead zones. Incentives for transitioning to organic agriculture are needed to help farmers remain economically viable. Let’s truly “Green Up” Vermont.

  • Peter Starr

    Lake Champlain is turning in to a toilet bowl and no one will care until it is too late!

  • John Klar

    “A recent study prepared for the Lake Champlain Basin Program found atrazine levels in streams feeding Missisquoi Bay and St. Albans Bay that are high enough to be toxic to plant life, but officials at the Agency of Agriculture, Food and Markets say they’re not worried.”

    So let me get this straight. VAAFM is enforcing new RAP’s on tiny little farms (with 5 cows or horses) while turning a blind eye to atrazine because it is killing off the consequences from phosphorous run-off, and they’re not worried because it only runs off fields when it rains… When are citizens going to comprehend that the VAAFM is the enemy of a healthy ecosystem and a co-conspirator with industrial interests? VAAFM creates more and more rules to stifle small farms in exchange for ever-growing powers (and paychecks) for its bureaucratic self.