2026 Environmental Health Program Highlights

The Environmental Health Program advanced understanding of per- and polyfluoroalkyl substances (PFAS) and other contaminants across diverse ecosystems. Research revealed how PFAS move through water, wildlife, and landscapes, helping clarify where exposures may occur. Studies within the Chesapeake Bay and Delaware examined how wildlife responds to contaminants, supporting early identification of potential ecological risks. Whereas soil surveys in northern New England showed that low pH, not proximity to PFAS sources, best predicted background PFAS levels, related groundwater studies demonstrated long‑distance PFAS migration to coastal seepage zones and highlighted that integrating plume characterization, groundwater‑flow modeling, and geophysical tools improves detection of coastal PFAS discharge and informs new multi‑site sampling strategies. A USGS study that leveraged field-realistic PFAS mixture exposure in fish demonstrated an innovative approach for linking real-world exposure profiles to biological responses, an emerging methodology likely to shape how future contaminant-mixture studies are designed. 

6PPD‑quinone is an emergent contaminant associated with ozone degradation of tires. Studies documented acute mortality in juvenile coho salmon exposed to roadway runoff containing 6PPD‑quinone and developed new methods for detecting this contaminant in fish tissue. This work provides foundational methods for documenting the occurrence and effects of 6PPD‑quinone in the environment. 

Safe drinking water remains a top priority for communities across the country, and USGS scientists this year advanced understanding of both the systems that deliver water and the tools used to evaluate its safety. One study screened water from private wells, public supplies, and bottled water using laboratory tests that measure biological activity rather than individual chemicals alone. The research found that samples from all three water types could activate biological pathways related to metabolism, oxidative stress, hormone signaling, and metal response, suggesting that standard chemical testing alone may not fully capture how low-level contaminant mixtures affect biological processes. These findings point to an opportunity to pair traditional chemical monitoring with newer effects-based tools for a more complete picture of drinking water safety. 

Complementing this work, a separate transdisciplinary review examined the more than 60 million people in the U.S. and Canada who rely on private wells, which fall outside the national regulations that govern public water systems. The review highlighted persistent challenges, including inconsistent state and local data on well locations and water quality, and the fact that fewer than one third of private well owners test their water regularly. It also outlined opportunities for researchers, communities, and policymakers to work together to close these gaps, from improving data infrastructure to better understanding the behavioral and financial barriers that keep households from testing and treating their water. Together, these studies underscore the value of combining scientific innovation with community engagement to protect drinking water quality across all supply types.