October 7, 2025
Since releasing our scientific study and press release on the persistence of ProcellaCOR in Lake George sediments, we’ve received many thoughtful questions from community members and the media. Some of these questions reflect curiosity about science and others focus on what the findings mean for Lake George. Several touch on the broader issue of how aquatic invasive species should be managed in the future, in Lake George and beyond.
We want to address as many of these questions as we can in one place, to both clarify what our research shows and to explain what it doesn’t. Our goal is transparency: sharing information, acknowledging what we don’t know yet and outlining the next steps that we believe should guide decisions moving forward.
Below, you’ll find answers to some of the most common and important questions raised so far. If you don’t see your question here, we encourage you to continue reaching out. We’ll continue listening and we’ll update our community as soon as we can.
Thank you for your continued engagement and support.
SCIENCE & FINDINGS
If ProcellaCOR breaks down quickly in the water, why does it matter if it’s found in sediments?
Sediments are home to organisms like chironomids (tiny midges) and other organisms that are an essential part of the lake’s food web.
Persistence of the herbicide in sediments means that there is a chance there is continuous, long-term exposure of the chemical to these organisms.
Unlike temporary disturbances to these tiny midges during activities such as hand-harvesting, this chemical exposure doesn’t go away in days or weeks. Our study shows that the chemical has lasted in the lake’s sediments for more than a year.
Does persistence in sediments prove ecological harm?
We are not sure. But persistence does indicate a higher ecological risk and the need to research this question further.
Our study shows persistence that prior assumptions and reviews of the herbicide did not account for.
How is your research different from previous studies or reviews from the EPA or others?
EPA approvals mostly relied on short-term laboratory and limited field studies.
Our work is the first long-term field study of sediments, showing real-world behavior in the environment of the herbicide over an extended time.
What’s the difference between surface and sediment cores, and why does that matter?
In our study, surface samples represent the top few centimeters of sediment. Sediment cores are deeper samples, in our study about 15 centimeters for most cores, and can reveal how the chemical migrates within the sediment.
How is it possible for the chemical to be in the sediment but not the water? How do we know it isn’t in the water?
ProcellaCOR is designed to move out of the water column relatively quickly, which is why it’s often described as “short-lived” in water. But the chemical has a strong attraction to organic material, and lake sediments are rich in this material. This means that the herbicide moves from water into the sediment, where it can bind to the organic material and persist for a long time.
When our team tested water samples, we generally saw ProcellaCOR disappear from the water within hours, consistent with prior studies. But when we looked deeper in the lakebed, we found the parent compound and its degradants persisting for more than a year.
This is why our study is significant: it shows that even if water tests read as a “non-detect,” the chemical can still be present in the sediments, where organisms live and where long-term exposure to these organisms could occur.
What exactly are the breakdown products you found?
In addition to the parent herbicide florpyrauxifen-benzyl, we detected its degradants, the chemical compounds it breaks down into as it moves through the environment.
These degradants are florpyrauxifen, hydroxy-florpyrauxifen, hydroxy-FPB, dechloro-FPB and dechloro-florpyrauxifen (see Figure 3 from our study).
These degradants are part of why long-term monitoring is important: while they are expected in any herbicide application, their persistence in sediments is poorly understood.
Our findings show that most of these remain detectable for more than a year after application.
Are the amounts of the herbicide and its breakdown products declining over time?
It’s unclear. We’ll better understand the long-term trends in the concentration of the herbicide after we sample the bays again next year.
Did lake circulation play a role in the fate and transport of ProcellaCOR?
Yes. Lake George is a large lake with complex water currents. Our research found that lake circulation likely explains the spatial pattern of toxic degradants and the parent compound within and just outside the dilution zones of each bay.
This lake circulation reinforces that what happens in a lab setting or a small pond may not reflect real-world behavior of a chemical in a dynamic lake ecosystem like Lake George.
LAKE GEORGE ECOLOGY
Why are chironomids important?
Chironomids are small midges, belonging to the scientific order Diptera (flies), that spend most of their life in lakebed sediments.
Fish and other animals depend on them as a food source, since these types of invertebrates are an important component of the food web.
If chironomids are chronically stressed or reduced, this could impact other parts of the food web.
Why didn’t you research fish and birds?
Our study focused on water, plants and sediments because they are the most direct points of contact with herbicides after application.
Directly studying invertebrates, fish and birds would require more planning than we were afforded due to the timing of the herbicide application.
HUMAN HEALTH & SAFETY
Is drinking water safe?
Nothing in our data indicates human health or drinking water risks. Our concern is ecological, not drinking water or recreation.
Should people who eat Lake George fish be concerned?
Nothing in our data suggests human health risk from eating Lake George fish at this time.
Do your scientific findings impact swimming or fishing?
Recreational use of Lake George remains safe.
MANAGEMENT & POLICY
Does this mean chemicals should never be used in Lake George?
The LGA is open to all possible lake management tools, and we support effective management of invasive species. But, in Lake George, hand-harvesting has proven effective for nearly 40 years.
Since 2009, the LGA has invested nearly $2 million into the Lake George hand-harvesting program, and we invest our time into assisting the Lake George Park Commission (LGPC) and contracted divers as needed.
We believe a comprehensive management plan should be created prior to any other potential future use of chemicals in Lake George.
What about other Adirondack Lakes that have used or want to use ProcellaCOR?
We believe that our findings point to the need for caution and further study of ProcellaCOR’s long-term use. At the least, we hope that the New York State Department of Environmental Conservation (DEC) and the Adirondack Park Agency (APA) consider our new science in future permitting.
We plan to expand our own research in other lakes where ProcellaCOR has been used to understand long-term persistence in these ecosystems, especially where the herbicide was used earlier than it was in Lake George (pre-June 2024).
How will the LGA work with the LGPC and other agencies moving forward?
We’ve already shared our findings with the LGPC, the DEC and the APA. We believe the best next step is a collaborative, science-based management plan that weighs all methods and evaluates long-term risks.
Creating a management plan for Lake George would fall on the organization that has regulatory and enforcement capabilities for the Lake, which is the Lake George Park Commission.
What is a management plan?
A management plan provides a science-based roadmap for how invasive species are controlled in Lake George. It should weigh the effectiveness and risks of all methods, establish protocols for monitoring and ensure long-term decisions aren’t made on short-term assumptions. It should include a robust stakeholder engagement process to ensure all perspectives and input are considered when making management decisions.
The LGA’s Executive Director Dr. Brendan Wiltse is a NALMS Certified Lake Manager and has helped create management plans for other Adirondack Lakes. We believe that, including the LGA, the LGPC has access to several knowledgeable regional stakeholders it could tap into to ensure that science, a full suite of management tools and other considerations are weighed to create an effective Lake George Aquatic Invasive Species Management Plan.
Do we know the Lake George Park Commission's plan to assess further?
In a recent Lake George Mirror article, the Park Commission did state that it has “no plans to treat milfoil beds in other bays in Lake George with ProcellaCOR in 2026.” We commend the LGPC for stating this publicly, but we do not know what this means for post-2026 Lake George treatment or assessments.
The Park Commission did conduct its own post-treatment plant surveys up to 60 days after and those can be found here. Some LGA staff have conducted milfoil plant monitoring days in 2025 with the LGPC, but we are not aware of the LGPC’s plan to conduct more in-depth assessments since application or going forward.
We will continue to advocate for a science-based, collaborative management plan before any further chemical use is considered.
What about the benefits of ProcellaCOR’s ability to kill milfoil? How do you weigh the risk versus reward of its use?
While ProcellaCOR does kill Eurasian Watermilfoil effectively in the short-term, the question we are investigating is the long-term impacts of chemical use on the Lake George ecosystem.
Our findings show that the herbicide can persist longer in the environment than previously thought, which raises ecological concerns.
Hand-harvesting has managed Eurasian Watermilfoil effectively in Lake George for nearly four decades, and we believe that proven, non-chemical methods should remain the primary choice while science continues to evaluate risks of chemical treatments.
PROCESS & TRANSPARENCY
Why are you publishing this study now?
We have successfully been a lake protection organization for 140 years, since 1885, because we’ve long advocated for the protection of the plants, animals and people that depend on a clear and clean Lake George.
So, this commitment to keeping Lake George clear and clean for at least another 140 years is tied to the community of people that support our work.
This means sharing our findings now with our members and the greater Lake George and New York communities while going through the time-intensive peer-review process.
What does “pre-print” mean?
A pre-print is a full scientific study shared publicly before or during peer review. It allows transparency and invites early scrutiny while the peer review process is underway.
In our pre-print version of our study, published on bioRxiv, we have several co-authors spanning multiple organizations, including the LGA, Paul Smith's College and the Darrin Fresh Water Institute. We in part conducted our research with these co-authors and other organizations as a first layer of rigor and fairness, before the formal peer-review process is initiated.
How long does peer review take?
Scientific peer review can take anywhere from a few months to a year. During the formal peer review process, independent experts in the field provide critical review of the manuscript to ensure it meets the highest scientific standards.
What’s next for the research team?
Continued sediment monitoring in Lake George, ecological surveys of plants and animals in the treated bays, and sampling in other Adirondack lakes. We are committed to long-term study.
Doesn’t RPI have an institute on the Lake with scientists who could help?
Yes. The Darrin Fresh Water Institute in Bolton has long been a pillar of Lake George science and research, first established in the 1960s and first supported by The FUND for Lake George (now the LGA) in the 1970s. Some of the scientists involved in our research and report are from this Institute, in addition to scientists from Paul Smith’s College.
How was this research funded?
The LGA’s members, who provide monetary donations and support to our organization, along with the LGA’s scientific partners, supported this work. This means that our research was independent with no industry funding.
Please consider contributing to our organization if you find our research insightful, useful, or want to back real-world science in the Queen of American Lakes, the largest water body wholly within the Adirondack Park.
ProcellaCOR Research Takeaways
These FAQs reflect the many thoughtful questions that we’ve received, and we hope the conversation continues. Science takes time. But so does building trust and understanding among our community and partners.
Ultimately, our research shows that ProcellaCOR behaves differently in Lake George than previously assumed, which raises new questions about its long-term persistence and ecological impacts. While drinking water and recreation remain safe, ecological uncertainties remain and demand careful attention.
Our commitment is to continue our research, share what we learn as openly as possible and advocate for management decisions that are grounded in rigorous science and a long-term lens. We value our continued partnerships with the Lake George Park Commission, Department of Environmental Conservation, Adirondack Park Agency and other key stakeholders.
Together, we can ensure that decisions about Lake George are made with its long-term ecological health always at the center. Lake George is an invaluable resource and cornerstone in so many families’ multi-generational stories. The Lake deserves nothing less than our utmost care.
