PFAS within Landfills, Leachate and Generic Wastes

Only a small contingent of states have promulgated drinking water maximum contaminant level (MCL) standards for per- and poly­flu­o­roalkyl substances (PFAS) below the federal advisory of 70-parts per-trillion (ppt). And yet, a growing number of state agencies are actively sampling for PFAS to determine their occurrence, levels and potential envi­ron­men­tal pathways. The California State Water Resources Control Board (CSWRCB) has been actively inves­ti­gat­ing and sampling for PFAS since 2019, and many experts believe new MCL standard(s) are forthcoming for drinking water and potentially for biosolids and waste streams.

California state officials are sampling for PFAS in phases, concen­trat­ing on sites they suspect have been impacted the most. Phase one includes airports and landfills, which represent two of the likeliest depositories for these resilient compounds. Airports were easy targets because of their historical use of aqueous film forming foams (AFFFs), which intrin­si­cally contain PFAS, while landfills represent the end-point for PFAS-containing products like furniture, textiles and carpeting. In this edition of Breaking Down PFAS, we will look closer at landfills and why they serve as important battle­grounds in the fight against PFAS.

There are an estimated 4,700 PFAS used globally for industrial, business and personal uses, making them difficult to track. With the potential to release PFAS into the environment via infil­tra­tion, surface runoff, leachate, evaporation or off-gas emission, landfills are useful vantage points to study these pervasive chemicals. Visit any municipal landfill, and you will likely run across shampoo bottles, non-stick pans, fast-food packaging and scores of other PFAS-laden waste. In some cases, PFAS can migrate into the soil and or surface water and groundwater. The fate of PFAS within landfills is controlled by a combination of biological and abiotic processes. 

Further compli­cat­ing sampling and treatment is the presence of PFAA precursors within the leachate, such as fluo­rotelomer carboxy­lates (FTCAs). Recent studies have shown that landfill leachates may contain precursors, which can be converted into persistent and non-biodegrad­able perflu­o­roalkyl acids (PFAAs) in the environment or during wastewater treatment processes. Through oxidation, FTCA compounds can transform into perflu­o­roalkyl carboxy­lates (PFCAs, e.g. PFOA and PFHxA), associated with potential health effects. This can happen through microbial activities or chemical oxidation, processes associated with conven­tional wastewater treatment, as well as within natural systems. That means that traditional treatment processes actually have the potential to convert these precursors into more toxic and persistent PFAAs. In some cases, researchers have discovered higher concen­tra­tions of PFAS in treated leachate than in its raw state. 

• Publicly-owned treatment works (POTWs) may set more stringent restric­tions on leachate acceptance.
• Envi­ron­men­tal liability will likely increase for landfill leachate.
• Leachate collection/management systems may be impacted.
• Data accuracy—no EPA approved method for analysis of PFAS in leachate at this time.
• Traditional leachate treatment tech­nolo­gies may not work for targeted PFAS removal.

The significant amount of PFAS observed and or suspected within landfills has led to increased concern over leachate management. In Vermont, statewide studies discovered PFAS in both lined and unlined landfills. “PFAS in landfill leachate is pervasive and has been detected at significant concen­tra­tions with respect to the EPA guideline of 70 ppt, with the potential for adverse envi­ron­men­tal impacts,” reads a report from the state Agency of Natural Resources. Similar studies are underway in Michigan, New Hampshire, New York and California. EPA has recently awarded projects to identify source, occurrence, trans­for­ma­tion and treatment of PFAS within wastewater and biosolids.

The current phase of California’s sampling initiative focuses on wastewater treatment plants, another critical stop on the PFAS trail. Beginning this October, publicly-owned treatment works (POTWs) will be required to sample and analyze influent and effluent, as well as reverse osmosis concentrate, for dozens of specified PFAS. And while California has not yet released an MCL for any specific PFAS, the state recently lowered its response levels from 70 ppt to 10 ppt for PFOA and 40 ppt for PFOS. As PFAS in excess of the response levels is found in water supply wells, the water treatment facility will either have to notify customers, provide treatment or possibly shut down the affected source. 

Breaking Down PFAS will be providing ongoing coverage of these state-by-state sampling efforts. For more information on what is happening in your area, reach out to one of our PFAS experts below.