On January 14, 2025, the U.S. Environmental Protection Agency (EPA) released a draft risk assessment, or scientific evaluation of the potential human health risks associated with the presence of toxic per- and polyfluoroalkyl substances (PFAS) chemicals in biosolids, also known as sewage sludge.
According to EPA the findings for the draft risk assessment show that there may be human health risks associated with exposure to the “forever chemicals” PFOA or PFOS with all three methods of using or disposing of sewage sludge – land application of biosolids, surface disposal in landfills, or incineration. Once finalized, the assessment will help EPA and its partners understand the public health impact of forever chemicals in biosolids and inform any potential future actions to help reduce the risk of exposure.
Draft Risk Assessment
The EPA’s draft risk assessment focuses on a specific and narrow population of people that EPA considers most likely to be exposed to PFOA or PFOS from the land application of biosolids or through consumption of products from land where biosolids were used as fertilizer. The draft risk assessment scientifically models hypothetical human health risks for people living on or near sites impacted by PFOA or PFOS or for people relying primarily on those sites’ products (e.g., food crops, animal products or drinking water). The preliminary findings of the draft risk assessment indicate that there can be human health risks exceeding EPA’s acceptable thresholds, sometimes by several orders of magnitude, for some scenarios where the farmer applied biosolids containing 1 part per billion (ppb) of PFOA or PFOS (which is near the current detection limit for these PFAS in biosolids).
These modeled scenarios include farms with one application of biosolids at a rate of 10 dry-metric-tons per hectare and 40 consecutive years of biosolids land application at this same rate. The modeling in this assessment also finds human health risks exceeding the EPA’s acceptable thresholds in some scenarios where biosolids containing 1 ppb of PFOA or PFOS are placed in an unlined or clay-lined surface disposal unit. Once finalized, EPA will use the risk assessment to help inform future risk management actions for PFOA and PFOS in sewage sludge.
For the incineration scenario, risk is not quantified due to significant data gaps. EPA recognizes that certain “hot spots” and specific farming operations may have higher levels of PFOA or PFOS if contaminated sludge was applied, and that further collaboration with impacted operations and other federal agencies will be important to fully understand risks and support impacted farmers. The actual risks from exposure to PFOA or PFOS will vary at farms that land-apply biosolids or at biosolids disposal sites based on the amount of PFOA or PFOS applied, as well as geography, climate, soil conditions, the types of crops grown and their nutrient needs and other factors.
Under EPA’s PFAS Strategic Roadmap, the agency has provided tools to restrict PFAS from entering the environment and to hold polluters accountable, including increasing reviews of new PFAS before they enter commerce and encouraging states to use their Clean Water Act permitting authorities and industrial pretreatment programs to require industrial dischargers of PFAS to remove them before sending their effluent to the environment or to wastewater treatment plants. Moving forward, EPA is working to set technology-based limits on discharges from several industrial categories—including PFAS manufacturers, electro- and chrome-platers and landfills—under the agency’s Effluent Limitations Guidelines program.
Where Do PFOA and PFOS End Up?
Landfills and the solid waste industry face the larger challenge of being held accountable even though they are not PFAS or PFOS generators, because these products used by consumers or manufactured with the substances ultimately end up in landfills or wastewater treatment plants.
EPA and State Actions on Forever Chemicals
Under EPA’s PFAS Strategic Roadmap, the agency has made progress in establishing some standards to protect communities from PFAS pollution. These actions include finalizing the nation’s first drinking water standards for PFAS, holding polluters accountable to clean up PFAS across the country and declaring PFOA and PFOS hazardous substances under the Superfund law.
Several states have begun monitoring for PFAS in sewage sludge and published reports and data that are publicly available. Some states continue to collect additional sewage sludge PFAS monitoring data.
Where to Find the Sludge Risk Assessment
Draft Sewage Sludge Risk Assessment for Perfluorooctanoic Acid (PFOA) and Perfluorooctane Sulfonic Acid (PFOS), will be available for public comment for 60 days following announcement in the Federal Register. Learn more about the draft risk assessment and how to comment on it. Also read about other recent EPA actions to help address PFAS in Biosolids. EPA will hold a public webinar on Wednesday, January 15, 2025 at 12:00pm ET. Register for the webinar using the webinar registration link.
PFOA and PFOS Removal or Destruction
While this blog is an alert to upcoming regulatory policy or discussion, there are a number of proven methods to remove PFOA and PFOS from effluent liquids, wastewater, landfill leachate, and biosolids. Please use our free resources to learn more.
The objective of this study was to evaluate a cross-section of full-scale on-site landfill treatment systems to measure changes in PFAS concentrations. Leachate samples were collected before and after treatment from 15 facilities and were evaluated for 26 PFAS, including 11 perfluoroalkyl carboxylic acids (PFCAs), 7 perfluoroalkyl sulfonic acids (PFSAs), and 8 perfluoroalkyl acid precursors (PFAA-precursors). The transformation of precursors was evaluated by the total oxidizable precursor (TOP) assay. Results showed no obvious reductions in total measured PFAS (∑26PFAS) for on-site treatment systems including ponds, aeration tanks, powdered activated carbon (PAC), and sand filtration. Among evaluated on-site treatment systems, only systems fitted with reverse osmosis (RO) showed significant reductions (98-99 %) of ∑26PFAS in the permeate. Results from the TOP assay showed that untargeted PFAA-precursors converted into targeted short-chain PFCAs increasing ∑26PFAS in oxidized samples by 30 %, on average.
Overall, the results of this study confirm the efficacy of RO systems and suggest the presence of additional precursors beyond those measured in this study. SCS is part of the technical advisory group for this collaboration of the schools in Florida and the EPA. SCS’s Liquid Management Practice is helping the group with on-site work at landfills.
Chen Y, Zhang H, Liu Y, Bowden JA, Tolaymat TM, Townsend TG, Solo-Gabriele HM.
Waste Manag. 2022 Sep 6;153:110-120. doi: 10.1016/j.wasman.2022.08.024. Online ahead of print.
PMID: 36084369
The following universities with EPA are affiliated with the study:
SCS Engineers is hosting a panel on proposed PFAS regulations as EPA continues to work on its goal of adding PFOA and PFOS as hazardous constituents under CERCLA – aka Superfund. EPA is also considering adding certain PFAS as hazardous constituents under Appendix VIII of the Resource Conservation and Recovery Act or RCRA, giving EPA authority to require RCRA corrective action for PFAS at RCRA sites. With data for about 14 PFAS constituents, including some of the newer ones commonly known as GenX, and based on toxicity data, the EPA supports the development of standards for risk-based concentration levels and risk screening levels for ingesting PFAS.
In July’s client webinar, our panelists aim to bring clarity and advice to those operating landfills that may become subject to regulations. The free webinar features a panel of speakers clarifying the recent plans, headlines and health advisories surrounding PFAS, as well as sharing some promising leachate treatment options. SCS’s engineers, scientists and landfill operations experts will speak during the forum and answer your questions. They are also available for follow-up after the 2 p.m. July 21 webinar.
Landfill operators who manage waste streams, leachate and sludges possibly laden with PFAS can attend this event and learn about the latest regulatory changes and proposals surrounding PFAS.
Reprint from a Recycling Today article by Managing Editor Bob Gaetjens.
As the EPA considers regulating PFAS, SCS Engineers helps bring clarity and advice to those operating landfills that may become subject to regulations.
Per- and polyfluoroalkyl substances (PFAS) are under the sharp gaze of the U.S. Environmental Protection Agency (EPA), which plans to determine how toxic the substance is.
There now is data for about 14 PFAS constituents, including some of the newer ones commonly known as GenX. Based on toxicity data, the EPA supports the development of standards for risk-based concentration levels and risk screening levels for ingesting PFAS. The state of Maine announced earlier this year a ban on PFAS in landfill leachate.
The EPA is considering whether to propose that perfluorooctanoic acid (PFOA) and perfluorooctanicsulfonic acid (PFOS) be classified as hazardous PFAS constituents under Appendix VIII of the Resource Conservation and Recovery Act (RCRA), giving the federal agency the authority to require corrective action for PFAS and RCRA sites.
It is with this background that SCS Engineers is hosting a webinar featuring a panel of speakers clarifying the recent plans, headlines and health advisories surrounding PFAS, as well as sharing some promising leachate treatment options. SCS’s engineers, scientists and landfill operations experts will be featured during the forum and can be available for follow-up after the 2 p.m. July 21 webinar.
Landfill operators who manage waste streams, leachate and sludges possibly laden with PFAS can attend this event and learn about the latest regulatory changes and proposals surrounding PFAS.
Certificates of attendance are available for attendees who registered on Zoom and attended the live session.
Corporate Headquarters
3900 Kilroy Airport Way Suite 300
Long Beach, CA 90806
Telephone
1 (800) 767-4727
1 (562) 427-0805 | FAX
Contact Us
