Cornell University students have tested more than 500 water samples from 300 bodies of water, building a public map of PFAS contamination that covers all 11 Finger Lakes and smaller waterways across the region. Their results show generally low concentrations in the lakes, alongside higher readings in some standing waters near airports and fire-training sites.
The students screened samples for 24 common per- and polyfluoroalkyl substances, or PFAS, according to a Cornell Chronicle report on the project. Their interactive map is intended to let residents see where samples were collected and how results vary by location; a sample from a stream or pond is not a test of anyone's tap water.
Where the higher readings appeared
Cornell civil and environmental engineering professor Damian Helbling began hearing from residents in 2023 as federal regulators moved to limit certain PFAS in drinking water. People wanted to know what was in nearby lakes, creeks and ponds, but Helbling said there was little local data to answer them.
Undergraduates in his research group started sampling in 2024. They collected water from lakes and tributaries as well as smaller ponds and places where rainwater persistently pools. Alex Van Den Hende, then a student, built the public-facing map before the first sample was taken; the team has continued refining it as the dataset grew.
The students found that PFAS concentrations across the Finger Lakes were generally low. The higher readings, including some above New York state guidance values, were largely in standing water near airports and fire-training stations. Aircraft de-icing fluids and firefighting foams appear to contribute at those sites, Cornell reported, and readings there declined over time.
Those higher-reading sites are not drinking-water sources and often are isolated from other waterways, Cornell reported. That limits the immediate implications of the results, but does not erase the contamination or establish that every place in the region has been tested. The researchers said the region's large volume of surface water may dilute PFAS, though that explanation is not proof of a source or fate for every chemical detected.
PFAS are persistent chemicals used in many products. Exposure to some compounds has been linked to health problems, but this surface-water sampling alone cannot determine an individual resident's exposure or health risk. The results also vary by chemical, site and sampling time; an overall regional finding should not be applied to an unsampled creek, private well or municipal drinking-water system.
A baseline for future monitoring
Helbling said repeated sampling across many sites gives the region a baseline against which later measurements can be compared, particularly if new industries arrive. The students hope to use the dataset to identify places where monitoring or source control should be a priority, and to help shape state PFAS monitoring in other regions.
Current team members include chemical engineering student Madeline Adams and civil engineering student Gregory Pepin. Helbling's group meets weekly with graduate researchers studying how to trace PFAS sources, how the chemicals change in the environment and how they might be captured or destroyed.
The team has presented its work at nearly a dozen conferences and meetings of watershed groups and municipal organizations, with help from the Cornell-based New York State Water Resources Institute. Helbling said communicating the science to residents has been an important part of the project, not just collecting samples.
The institute and the New York State Department of Environmental Conservation have funded the work. As more samples are added, the map can help residents distinguish broad regional patterns from specific places that warrant closer attention.
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