Friday, January 19, 2024

It’s Debatable: Milfoil herbicide

Invasive Eurasian watermilfoil.

Editor’s note: This “It’s Debatable” column ran in the Jan/Feb 2024 issue of Adirondack Explorer magazine.  In this regular column, we invite organizations and/or individuals to address a particular issue. Click here to subscribe to the magazine, available in both print and digital formats:

The Question: Should ProcellaCOR be used to kill park milfoil?

Scientific evidence missing:

Adirondack communities are increasingly using the contested pesticide ProcellaCOR to kill invasive milfoil without scientific knowledge of what harm it might do to other plants, invertebrates, fish and the quality of the water itself in the lakes we love and enjoy.

Adirondack Park Agency (APA) approvals for ProcellaCOR’s use cannot rely on limited information and assumptions. We need scientific planning, monitoring and assessment. As a lake scientist, I believe we have to make decisions based on what we know, not what we hope.

An APA representative has noted ProcellaCOR’s “growing track record.” But the only record is its increased use in park lakes without scientific follow-up on broader effects. Officials “assume ProcellaCOR will negatively impact native plants …but ultimately be beneficial.” We have no idea whether that’s true. Long-term benefits, including the return of native plants and animals, has yet to be verified.

It is said that ProcellaCOR targets milfoil, presumably without harming other species. But it also targets valuable natives like Nitella, a vital macroalga. ProcellaCOR is an endocrine disruptor intended to kill aquatic plants and it does for a period. But we don’t know what collateral damage it might be doing to the food chain.

Among effects yet to be studied is the phenomenon known as “chemical drift” in which ProcellaCOR might move from the application site affected by milfoil to non-targeted waters. The US Environmental Protection Agency (EPA) permit label restricts its use to still waters. Yet ProcellaCOR applied in Minerva Lake spread beyond the application site to include the whole lake, becoming a possible danger to wetlands and other sensitive areas.

The EPA toxicity test uses only a small number of plant and animal species found nationwide and do not cover important Adirondack species. It’s our job to investigate further.

I have provided detailed comments to the APA regarding the Lake George Park Commission’s application filed in March of 2022, urging a careful scientific approach to avoid damaging the lake and potentially even the people who swim in it and drink the water.

I grew up on Lake George in the days when DDT used to kill insects also left us without loons and bald eagles. It took 40 years for them to return. We cannot repeat the chemical mistakes of the past. We must learn all we can to make the best-informed decisions.

Dr. Carol D. Collins, limnologist, author of papers on algae and macrophytes, developer of mathematical models of lake ecosystems, Lake George

Chemical option is justifiable:

With the recent state permit granted for the use of ProcellaCOR in Paradox Lake, there has been much discussion among lake associations regarding its usage. We agree that ProcellaCOR may well have a role in current aquatic invasive species management, but that role must be carefully defined and monitored and should only be considered when all other options have been explored and undertaken.

The use of a wide-spectrum herbicide should not be considered lightly, but as a last attempt to remediate an invasion of milfoil whose growth is beyond the capacity of hand harvesting and the means to afford such harvesting methods.

In the early stage of invasion, the year-over-year growth of Eurasian milfoil is typically linear, with a moderate growth each year that can be effectively managed with traditional harvesting methods. There are conditions, however, that increase the growth rate beyond the ability to control it – these include increased boat traffic which can fragment and spread the plants; prevailing winds that also contribute to fragment spread; and most importantly, unmanaged areas within the lake that spread into areas that were once well-managed.

When these situations arise, and the growth rate becomes exponential year-over-year, then ProcellaCOR becomes a viable alternative, provided other criteria are met. But to justify ProcellaCOR application, there must be a quiescent water body, a well-known lake bottom topography, the absence of human consumed lake water in the vicinity of the planned usage and minimal impact on native aquatic species – plant and animal. Most importantly, a plan for multi-year testing of ProcellaCOR and its metabolites must be in place before application, not only within the application area, but within the entire lake body and in any outlets from the lake into creeks, streams and rivers. And, once the ProcellaCOR is applied, continued lake bottom monitoring and harvesting as needed is important so as to not allow further spread or reinvasion.

We acknowledge that the product is relatively new, and that experience with ProcellaCOR within the Adirondack Forest Preserve is limited to two lakes at present, but the use outside the Adirondacks is becoming widespread. The current available research has shown little cause for health concerns in aquatic animal life or in humans who use the waterways after treatment.

Adaptive lake management for invasive species abatement is ideally suited for most milfoil invasions in their early stages. But when infestations have grown beyond the ability to economically control growth using methods such as hand or vacuum harvesting, then ProcellaCOR is a viable alternative to consider.

Scott Ireland, executive director, Adirondack Lakes Alliance; president, Schroon Lake Association, Schroon Lake

Photo at top: Invasive Eurasian watermilfoil. Explorer file photo by Mike Lynch.

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The Adirondack Almanack publishes occasional guest essays from Adirondack residents, visitors, and those with an interest in the Adirondack Park. Submissions should be directed to Almanack editor Melissa Hart at

22 Responses

  1. Nathan says:

    we never learn from Racheal Carlson and her book “Silent Spring”

    In 20 years it will be a demon like DDT, by the time it’s dangers are discovered species will be gone or nearly gone…Same stupid idea, let’s use poison to solve every problem.

    Fresh glass of water? ( with 20PPM of percellacor). I would rather not have our children discovering cancer, sterility down the road!
    every dangerous chemical was once thought safe, only through time was it found to not be safe. But hey let’s dump it in every lake, stream, river and aquifer. drink it, eat in in our fish, animals who drink from waterways. ADA FAILS AGAIN!!

    • AdirondackAl says:

      This comment exemplifies why comment sections for articles are of limited value.

      • Pat Smith says:

        Yes Al, just be quiet and do as the bureaucrats and politicians tell you to do and don’t ask questions. Sheeple!

        • Rob says:

          So it is wrong to do as the bureaucrats and politicians say in this example but ok to follow their lead for climate change, using taxpayer dollars for affordable housing, let them tell us no more gas stoves or heating our home with natural gas to name a few. Good double standard

          • Pat Smith says:

            No double standard, the current renewable energy plan the state is following is destined to be an absolute disaster. Again bureaucrats and politicians, with no real understanding of how the grid works, creating laws and policies.

      • Nathan says:

        You are correct, you gave a great example!!! Cheers for pointing out in such a clear and precise way!

    • Samantha says:

      If you actually watched the agency presentation or researched anything in the application materials you would have seen the application is like 5 parts per billion. Billion, not million. Stop fear-mongering. That’s equivalent to less than a thimble in a swimming pool. There’s higher concentrations of gasoline and oil entering these same waters from motorboats and nearby roads. Lake George consistently has a septic/sewage leaking issue. Why don’t you push to ban motor boats and more homes along the lakeshore?

      • Rob says:

        Oh don’t say that. There are already a number of people who want to ban boats on lakes. It bothers them to have to listen to the noise

      • nathan says:

        Oh and how fast does it break down as an artificial chemical?? or does it merly dilute into the enviroment? You don’t think that it can build up over time in an aquifer? DDT was banned 50 years ago and is still found in the body fat of Penguins of Antartica where it was never even used within a thousand miles…Gasoline and oil are not nearly as toxic as most common *-icides. To be honest there should be a ban on 2 strokes and cleaning station at every boat launch. There are much more stringent requirements for sewage fields by lakes. So learn more facts before you swallow the hook and line?

        • Rob says:

          Why should 2 strokes be banned?? There are stringent requirements when sewage fields near lakes are built. They aren’t tested enough through their life. Don’t I just read a majority of them near Lake George are failing?? Before we know it taxpayers will be paying for them to be replaced

          • nathan says:

            4 strokes are much cleaner by 20-100X times cleaner, more fuel efficient. old 2 strokes are 40:1 or even a few at 25:1 oil mix. 4 strokes are way cleaner for the enviroment and does not require catalytic converters (yet) or extreme costs. Not having billowing clouds of smoke behind the boat or in the marina is just common sense. I retired my old outboards to wall hangers and restored my johnson 69 1.5 Hp as memories as a kid. now use electric trolling motor or 4 stroke

            • Boreas says:

              The smoke is just part of it. That smoke is what comes out of the water because the exhaust is under water. The water strips out much of the oil in the smoke and leaves it as a slick on any body of water it is on. Logic would suggest a ban on sensitive waters within the Park.

              I have an old 9.9 hp Merc that I start up every year or two to make sure it works. I run it with the prop in a tank. When I am done, the tank has quite an oil slick and stinks like bejeezus. Not even safe to dump on the ground. I try to mop most of it up with an oil-absorbent pad. I should donate it to the Smithsonian.

              • Nathan says:

                lol, Your sentimental from old times like me. i often test run in 55 drum and it does leave quiet a mess. i have couple old ones, mercury9.9, but it sits now on a stand no longer used. After i used a 5 hp 4 stroke one time, i was shocked at how much cleaner and longer the run time on a tank. so i switched over and retired the oldies. nice not leaving a rainbow slick anymore!

        • Samantha says:

          The breakdown is in the presentation too. 2-6 days in aquatic setting, 3-8 days in sediment, 3-4 weeks for its metabolites in the sediment. Gasoline is a known carcinogen and known to be toxic. The EPA, DEC and Canadian authorities have all said procella cor (a synthetic hormone, not a traditional -icide) is safe to humans, fish and animals. The tests done now are a lot more thorough than back when DDT was around (there was no EPA so…..).

          Will save you the trouble from having to google it so it can answer your other questions you may have:

          • Nathan says:

            you go right on believing the company film.
            1)how safe are the break-down compounds?
            2) how much genetic damage does it do while active to plants, waterlife?
            3) A company does cost analysis, profit versus lawsuit losses. They still sell 2,4-d and it’s very well known how cancerous, how Atrazine is used a billion pounds a year and is super genetic disaster. A product that kills or damages anything is not safe at some level and time acrues those damages. Samantha sounds like a rep for procellor and need to stop trying to fool people!

          • Boreas says:

            Chemical breakdown numbers are only meaningful for single, short term applications of a chemical. The mere fact that this chemical may break down to become “safe” means that it is NOT a once-and-done treatment. The milfoil will return and the water body will need to be re-treated – ad infinitum. So as far as the aquatic environment is concerned, the chemical becomes an integral part of the ecosystem in the lake – good or bad. Then you start looking at acquired resistance in the target organism and potential long-term side effects in others. Another consideration – what is the effect of loading the lake with huge amounts of dead/dying milfoil after initial treatment?

            I suppose I am a pessimist, but once any invasive species is introduced, the cat is out of the bag. Even though early mitigation and elimination of an “inoculation” can be successful, it is rare. Choked lakes throughout the country is too late. Destruction of ash forests is too late. These interlopers are all looking for a way to expand their range. Humans are the perfect facilitators. With rapid, global travel, we need to accept – however reluctantly – of slow, global homogenization of species diversity around the planet. Once humans are gone, Nature will eventually get back to normal.

  2. Boreas says:

    Eradicating an invasive species is virtually impossible. You may be able to kill off milfoil in one body of water, but what good will that do? It will just find its way back from water bodies that aren’t treated. Do we need another possible “forever chemical” in our water bodies?

    • Fly in the Ointment says:

      Yes! The cure may be far worse than the disease. Why risk it? This herbicide has not had years of testing. In fact, most of the testing was done by the manufacturer. Have we all gone insane?

      • Long_Term_Matters says:

        U.S Government standards for acceptable levels of radiation exposure have been decreased by a factor of over 100,000 since the 1950’s, as we learn more about the dangerous long term effects of radiation exposure. Longitudinal research takes decades, and is expensive, so most research focuses on short term effects only. So we are unleashing a synthetic hormone into our lakes that has only been evaluated for relatively short term impact, primarily by the manufacturer. This is a failed regulatory model. What could possibly go wrong ?

    • nathan says:

      you got the exact point!

  3. Paul says:

    Sorry, how is just residing in the town where the agency might move be a conflict for the director.

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