PFAS contamination is widely recognized by regulators and researchers, but closed, unlined landfills remain an important and often overlooked source pathway.
Landfills have, often unknowingly, been accepting per- and polyfluoroalkyl substances (PFAS) waste for decades. Many landfills constructed before the 1990s were not subject to modern liner requirements, allowing pollutants to seep into surrounding soil, groundwater and surface water, or be emitted as landfill gas.
Based on published studies cited in the EM Magazine article:
- ~ 84% of PFAS remain in the landfill
- ~ 10% are carried away in contaminated drainage water (leachate)
- ~ 6% escape into the air.
PFAS contamination in drinking water is increasingly recognized by some regulators, including the U.S. Environmental Protection Agency, as a significant public health concern. It can also contribute to contamination of waterways and wetlands, where PFAS may accumulate in fish and wildlife over time, extending exposure risk beyond the original source.
With around 13 million people living within a mile of a landfill, and 1,946 municipal landfill facilities built before 1990, the question is increasingly urgent: how can decision-makers identify potential hotspots and implement protective measures?
In this article for the Air & Waste Management Association’s EM Magazine, Narayanan Raghupathi, vice president, environmental engineering, WSP in the U.S., outlines a framework for assessing PFAS risk and helping determine where action may be needed most.
For example, many closed, unlined landfills are in rural or long-established communities that rely on private wells and nearby surface waters for drinking, recreation and food. Early detection, clear communication and targeted mitigation strategies are commonly used to help inform and manage risk-reduction efforts.
Studies conducted by the U.S. Environmental Protection Agency have highlighted the potential impacts PFAS can have on human health and the environment.
“Understanding how PFAS persist, migrate and interact with groundwater and surface water can help prioritize site investigations and implement protective measures,” explains Raghupathi.
Management and mitigation approaches include interim measures, such as improving surface water controls and treating affected wells, as well as long-term strategies to capture and contain PFAS at the source.
As PFAS regulations continue to evolve, practical solutions and community engagement are expected to help play a role in reducing risks to both human health and the environment.
