PFAS Finger Lakes Map: Cornell-Led Project
Yes, a Cornell-led project has created the first in-depth map of PFAS contamination in the Finger Lakes region of New York. The map, developed by researchers at Cornell University in collaboration with state and local partners, compiles data from hundreds of water and sediment samples to show where per- and polyfluoroalkyl substances (PFAS) are present and at what concentrations.
Background: What Are PFAS and Why Do They Matter?
PFAS are a large group of human-made chemicals used since the 1940s in products like non-stick cookware, water-repellent clothing, firefighting foams, and food packaging. They are often called “forever chemicals” because they do not break down easily in the environment. Many PFAS compounds have been linked to health effects such as increased cholesterol, changes in liver enzymes, decreased vaccine response in children, and increased risk of certain cancers, according to the U.S. Environmental Protection Agency (EPA).
The Finger Lakes—11 narrow lakes in central New York formed by glacial activity—are a critical drinking water source for over one million residents. The lakes also support agriculture, tourism, and recreation. Understanding PFAS distribution in this system is essential for public health and for guiding future monitoring and remediation efforts.
The Cornell-Led Project: Scope and Methods
The project, led by researchers at Cornell University, aimed to create a comprehensive baseline of PFAS contamination across the Finger Lakes watershed. The team collected water samples from each of the 11 lakes, as well as from major tributaries, groundwater wells, and wastewater treatment plant outflows. They also analyzed sediment cores from lake bottoms to understand historical contamination.
Key steps in the mapping process included:
- Sampling at multiple depths and locations in each lake to capture spatial variability.
- Analyzing samples for over 40 individual PFAS compounds using liquid chromatography-tandem mass spectrometry.
- Mapping results using geographic information system (GIS) software to create visual heat maps of contamination.
- Comparing PFAS levels to New York State Department of Health (NYSDOH) drinking water maximum contaminant levels (MCLs) and EPA health advisories.
This approach allowed the team to identify not only which lakes have the highest PFAS concentrations, but also potential sources, such as airports using firefighting foam, industrial sites, or landfills.
Key Findings: Which Lakes Had the Highest PFAS Levels?
According to the project’s published data, the highest PFAS concentrations were found in lakes near known sources, particularly those close to airports and industrial areas. For example, Seneca Lake, which has a history of industrial activity and is near the former Seneca Army Depot, showed elevated levels of PFOS (perfluorooctane sulfonic acid), one of the most studied PFAS compounds. Similarly, Cayuga Lake, which receives runoff from the city of Ithaca and Cornell University, had detectable levels in some tributaries, though generally below state MCLs.
In contrast, more remote lakes like Canadice and Hemlock, which are part of the City of Rochester’s drinking water supply, had very low or non-detectable levels, indicating that their protected watersheds remain relatively pristine. The map also revealed that PFAS concentrations were generally higher in near-shore areas and in sediment than in open water, suggesting that contamination tends to settle and accumulate in lakebeds.
How to Read the Map and What It Means for You
The interactive map, hosted on a Cornell website, allows users to click on sampling locations and view the concentrations of various PFAS compounds. Each point is color-coded: blue for non-detect, green for low (below 10 parts per trillion), yellow for moderate (10-70 ppt), and red for high (above 70 ppt). The map also includes pop-up windows with detailed data, including sample date, compounds detected, and the laboratory that analyzed the sample.
For residents and municipal water suppliers, the map serves as a practical tool to:
- Identify whether their drinking water source is at risk.
- Prioritize future testing and treatment investments.
- Inform decisions about private well placement and testing.
It is important to note that the map shows PFAS concentrations in raw water, not necessarily in treated drinking water. Many water treatment plants already have activated carbon or ion exchange systems that can remove PFAS, so the finished water may have lower levels than the source.
Common Misconceptions About PFAS in the Finger Lakes
One frequent misunderstanding is that all PFAS are the same. In reality, there are thousands of different PFAS compounds, and they have varying toxicity and environmental behavior. The map focuses on a subset of 40 compounds that are most commonly detected and have the most health data. Another misconception is that if a lake shows a high reading, it is unsafe for swimming or fishing. While high PFAS concentrations in water are a concern for drinking, the risk from incidental ingestion during swimming is much lower. However, the NYSDOH does issue fish consumption advisories for certain lakes based on PFAS and other contaminants, so it is wise to check current guidance before eating fish from any Finger Lake.
What’s Next: Monitoring and Remediation
The Cornell project is not a one-time effort. The team has established a long-term monitoring plan to track changes in PFAS levels over time, especially as new regulations take effect. In 2024, the EPA set enforceable MCLs for six PFAS compounds in drinking water, which will require many water systems to install treatment. The map provides a baseline against which future improvements can be measured.
Remediation options for PFAS-contaminated lakes are limited because the chemicals are so persistent. In some cases, the most practical approach is to treat drinking water at the point of use or at the plant, rather than trying to clean up the entire lake. For sediment, capping or dredging may be considered in hotspots, but these methods are expensive and can disrupt ecosystems. The Cornell team is also studying natural attenuation processes and whether certain plants or bacteria can help break down PFAS, though this research is still in early stages.
Frequently Asked Questions
Is it safe to swim in the Finger Lakes with PFAS?
Yes, for most people. PFAS in lake water at the levels found in the Finger Lakes are not a significant risk from skin contact or accidental swallowing during swimming. The primary concern is long-term consumption of contaminated drinking water. If you have open cuts or swallow a lot of water, the risk is still minimal, but you can reduce exposure by showering after swimming and avoiding swallowing water.
Can I filter PFAS out of my drinking water at home?
Yes, certain home water filters can remove PFAS. Look for filters that use granular activated carbon (GAC) or reverse osmosis (RO). The NSF International certification mark (ANSI/NSF 53 or 58) indicates that the filter has been tested for PFAS removal. Be sure to replace filters according to the manufacturer’s instructions, as exhausted filters can release trapped contaminants.
How do I know if my private well is affected?
If your well is near a known PFAS source, such as an airport, industrial site, or landfill, you should have your water tested. NYSDOH offers guidance on certified laboratories that can test for PFAS. The cost is typically a few hundred dollars. If your well is in a remote, undeveloped area, the risk is lower, but testing is still recommended if you have any concerns.
What are the health effects of PFAS in drinking water?
Long-term exposure to certain PFAS has been linked to increased cholesterol, changes in liver enzymes, decreased infant birth weights, and increased risk of kidney and testicular cancer. The EPA has set health advisories and MCLs to protect against these effects. If your water exceeds these levels, you should consider using an alternative source or treatment.
Are PFAS levels in the Finger Lakes getting better or worse?
The data from the Cornell map is a baseline, so it is too early to say definitively. However, some PFAS compounds like PFOS and PFOA have been phased out of production in the U.S., so their levels in the environment may slowly decline. Newer replacement compounds, such as GenX, are being detected more frequently, and their long-term effects are still being studied. Continued monitoring will be needed to see the trend.
Conclusion
The Cornell-led PFAS map is a landmark resource for understanding and managing these persistent chemicals in the Finger Lakes. By providing a clear, data-driven picture of contamination, it empowers residents, municipalities, and regulators to make informed decisions. While the map reveals that some lakes have concerning levels, it also shows that many remain pristine, and it underscores the importance of ongoing monitoring and investment in water treatment.
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