PEREC researchers recently received a National Science Foundation (NSF) Rapid Response Research grant to collect and share data on the Potomac River sewage spill that occurred earlier this year.
Researchers from George Mason University’s Potomac Environmental Research and Education Center (PEREC) are leading an intensive study of the Potomac River Estuary following one of the largest sewage spills in U.S. history. Beginning in January 2026, ~240–300 million gallons of untreated wastewater entered the river after a major sewer line collapse. The research team is investigating how this sewage pulse of synthetic compounds, heavy metals, pesticides, fertilizers, antibiotics, PFAS, pathogens, and nutrients may have impacted water quality, aquatic life, and the overall health of the estuary.
To capture the river’s response, the scientists are collecting monthly surface, bottom water, and sediment samples at eleven locations spanning the freshwater reaches to brackish downstream waters. They will quantify the diversity of bacterioplankton, phytoplankton, zooplankton, invertebrate, and fish communities in the river along with water quality parameters such as nutrient concentrations and clarity. These rapid-response monitoring data collected shortly after the spill will be compared with a unique long-term dataset collected by Mason researchers since 1984. Together, these records provide an unprecedented opportunity to examine how a major pollution event reshapes river ecosystems and to track the earliest stages of ecological change.
The project will generate publicly accessible data that may inform future public health advisories, recreational use decisions, and environmental management strategies throughout the Potomac River watershed. Researchers also hope the study will serve as a model for responding to future sewage spill events across the nation. Graduate, undergraduate, and high school students will also participate in fieldwork, sample processing in the laboratory, data analysis, and public outreach.