How should we dispose of PFAS waste from contaminated sites in Canada?
January 09, 2020
January 09, 2020
Despite our steadily evolving understanding of the negative health impacts of PFAS, disposal of PFAS-contaminated waste remains unregulated
Slowly but surely, we’re learning more about per-and polyfluoroalkyl substances (PFAS). Today, when we look at remediating a contaminated site impacted by PFAS, we have a better understanding of what concentrations of PFAS might cause negative health impacts on humans. But an area that remains largely undefined and unregulated is how to best dispose of soil and groundwater with elevated PFAS concentrations. What should happen to these materials? We need to think about waste management and PFAS.
First, some background. PFAS, a class of human-made fluorine-containing organic chemicals, were developed in the late 1930s and, due to their combined water- and oil-resistant properties, have been widely used in industrial applications both as fluorosurfactants (for example, in aqueous film-forming foam for firefighting) and as heat-, oil-, grease-, and stain-resistant coatings (such as on textiles and in food packaging). Out of a suite of thousands of PFAS parameters, perfluorooctanesulfonate (PFOS) and perfluorooctanoic acid (PFOA) are the two most commonly known, and both are considered toxic and persistent.
Given the negative health consequences for humans understood to be associated with exposure to various PFAS, we have been seeing, internationally, the development of guidelines, standards, and—in some jurisdictions—regulations for specific PFAS in different types of environmental media, such as drinking water, groundwater, and soil. For example, in 2018, Health Canada established drinking water guidelines (DWGs) for PFOS and PFOA, as well as drinking water screening values (DWSVs) for nine additional PFAS.
And yet, despite our steadily evolving understanding of the negative health impacts of specific PFAS, the disposal of PFAS-contaminated waste remains unregulated. When I say “waste,” I’m referring to the impacted soil or water that we might manage at a contaminated site. But the issue of PFAS in the waste stream can stretch much further.
Landfilling typically serves as a common and accessible disposal method for most PFAS impacted waste. But, over the past year, the uncertainty of the long-term consequences and management of PFAS in landfill leachate has gained attention. Various US states have commenced sampling programs for PFAS in landfill leachate, and many US landfills now refuse to accept PFAS-contaminated soil and groundwater generated from remediation programs at impacted sites. Recently, the United States Environmental Protection Agency awarded $6 million to research the potential environmental impacts of PFAS in waste streams.
As more focus is placed on potential sources of PFAS contamination in the environment, we may see landfills in Canada refusing to accept PFAS-contaminated soil and groundwater from impacted sites.
Interestingly, we aren’t yet seeing this same focus on PFAS waste in Canada. In fact, despite the advancement of DWGs and DWSVs by Health Canada, Canada seems woefully behind many international governments in advancing policy and regulation regarding PFAS at all. To date, only British Columbia has established regulated standards for PFAS in environmental media (e.g., groundwater, drinking water, and soil). Even there, the list is short and select.
That said, the conversation around PFAS in Canada is growing. Generally, it starts with focus on source water protection, and trickles into discussions around brownfield redevelopment, property liability, insurance claims, and even excess soil management. Even if we set aside consideration of the disposal of PFAS-contaminated soil and groundwater from impacted sites, the widespread use of PFAS within commercial products means that these chemicals are commonly observed within the waste stream. It would seem naive to think PFAS waste disposal will not be part of this growing conversation.
Waste managers should pay attention. Canada is home to more than 2,000 active landfills. While some of these landfills have leachate collection and treatment systems (many don’t), the typical treatment process does not include mechanisms to treat PFAS. Waste generators should also pay attention. As more focus is placed on potential sources of PFAS contamination in the environment, we may see landfills in Canada refusing to accept PFAS-contaminated soil and groundwater from impacted sites.
Part of the challenge in managing PFAS waste will be understanding what kind of waste it is: hazardous or nonhazardous. In Canada, policy and regulation for waste management is generally formed at the provincial level. Decisions on how waste is to be managed flow from understanding how bad (or how hazardous) the waste may be. This understanding is usually developed by analyzing overall contaminant concentrations in the waste and testing their potential to leach and migrate to groundwater. Applying this same process to PFAS waste is quickly hindered by the lack of available laboratory methods for PFAS leach testing and the lack of established PFAS values to compare the results. But understanding whether the PFAS waste is “hazardous” or “nonhazardous” is important; the costs for disposing of hazardous waste can be four or more times higher than non-hazardous waste.
Given the lack of policy or regulation for the PFAS-contaminated sites we support in Canada, our team has had to be proactive. We have developed site-specific, or client-specific, best management practices frameworks for handling PFAS-impacted material generated as part of the investigation or remediation process. When making decisions within these frameworks, we consider relevant guidance at an international, national, and provincial level. Internationally, the Stockholm Convention on Persistent Organic Pollutants indicates PFAS waste should be either stored in a controlled landfill that protects against leaching to the environment or thermally destroyed at a very high temperature (minimum of 1,100oC). The Basel Convention on the Control of Transboundary Movements of Hazardous Wastes and Their Disposal indicates that wastes containing more than 50 mg/kg of PFOS must be disposed of in a manner that either destroys or irreversibly transforms the PFOS content, or in an “otherwise environmentally sound manner”—which perhaps we can assume means a controlled landfill.
Both the Stockholm and Basel Convention guidelines acknowledge that incineration at high temperatures is the only demonstrated method to destroy PFOS. Waste incinerators do exist in Canada—although there are far fewer of them than there are landfills. As a result, incinerators may be less accessible. Waste incineration is also generally much more costly than landfilling, so a good understanding of when it is the right option for PFAS waste is important. In Canada, we now have some values available at a Federal level to support that decisioning. In BC, there are provincially regulated values that can be considered.
Ideally, in the short-term, we should see a more focused effort from regulators to develop guidance and regulation specific to PFAS, including handling and disposing of PFAS waste from contaminated sites. In the interim, evolving site-specific PFAS waste decision frameworks can be an effective solution for supporting responsible management of PFAS-containing waste.