As a result, clients across industrial consumer sectors – automotive, textile, personal care and cleaning products, electronics, food and beverage, chemical manufacturing, medical devices, and others – have turned to Gradient to address various PFAS issues. PFAS represent a class of thousands of individual compounds, each with their own set of physicochemical properties. Many PFAS are highly stable and unreactive, while retaining the ability to repel both water and oil and reduce surface tension lower than other surfactants. The stability of these PFAS is attributed to their chemical structure, particularly the carbon-fluorine bond.
Gradient has extensive experience evaluating PFAS, from their potential accumulation in humans and ecosystems, to their source identification, fate and transport in the environment, and potential toxicity. Additionally, we are well versed in PFAS risk assessment and remedial decision-making, as well as in identifying where PFAS may be present in products, manufacturing processes, and supply chains, including historical reviews. Gradient’s PFAS experts include chemists, toxicologists, ecotoxicologists, epidemiologists, hydrologists, air quality and transport scientists, risk assessors, and database programmers who have experience in both long-chain PFAS (e.g., perfluorooctanoic acid [PFOA] and perfluorooctane sulfonic acid [PFOS]) and short-chain PFAS and fluoropolymers, including polytetrafluoroethylene (PTFE).
Gradient Expertise:
Publications:
Zhang, J; Zhao, S; Reid, K. 2025. “Navigating Consumer Product PFAS Regulations Across State Lines – Practical Strategies for Product Stewards.” To be presented at the PSX Conference, Houston, TX, September 16-18.
Prueitt, RL. 2025. “The Pivotal Role of Toxicology Data in Regulation.” Presented at the PLASTICS’ Fluoropolymers Conference 2025, Fort Meyers, FL, February 4-5.
Yeh, A; Prueitt, RL; Kerper, LE; Beck, BD. 2025. “Evaluating dermal absorption of perfluorooctanoic acid (PFOA) and implications for other per- and polyfluoroalkyl substances (PFAS).” Regul. Toxicol. Pharmacol. 156:105766. doi: 10.1016/j.yrtph.2024.105766.
Clyde, P; Zic, K; Rice, J. 2023. “Domestic Wastewater as a Nonpoint Source of PFAS Contamination in the US.” Presented at the SETAC North America 44th Annual Meeting, Louisville, KY, November 12-16.
Tuit, C; Calder, B; Ritter, E. 2023. “The Challenges of Finding and Mitigating PFAS in Supply Chain.” Presented at the Society for Chemical Hazard Communication (SCHC) Annual Meeting, Arlington, VA, September 30-October 5.
Campbell, J; Clewell, H; Cox, T; Dourson, M; Ethridge, S; Forsberg, N; Gadagbui, B; Hamade, A; Naidu, R; Pechacek, N; Peixe, TS; Prueitt, R; Rachamalla, M; Rhomberg, L; Smith, J; Verma, N. 2022. “The conundrum of the PFOA human half-life: An international collaboration.” Regul. Toxicol. Pharmacol. 132:105185. doi: 10.1016/j.yrtph.2022.105185.
Boomhower, SR; Kerper, LE; Chien, J; Beck, BD. 2020. “A Comparison of PFAS Serum Concentrations in the General Population to Points of Departure Used in Regulatory Guidance.” Presented at the Society of Toxicology (SOT) 59th Annual Meeting and ToxExpo, virtual.
Pizzurro, DM; Seeley, M; Kerper, LE; Beck, BD. 2019. “Interspecies differences in perfluoroalkyl substances (PFAS) toxicokinetics and application to health-based criteria.” Regul. Toxicol. Pharmacol. 106:239-250. doi: 10.1016/j.yrtph.2019.05.008.
Lemay, JC; Slagowski, NL; Kerper, LE; Sharma, M. 2019. “Occurrence, Distribution, and Bioaccumulation of Per- and Polyfluoroalkyl Substances (PFAS) in Minnesotan Freshwater Environments.” Presented at Battelle’s 10th International Conference on Remediation and Management of Contaminated Sediments, New Orleans, LA, February 11-14.
Project Examples:
PFAS Reporting Support. Gradient provided one-stop-shop services for a large commercial product manufacturer on Canadian and US federal and state obligations for PFAS reporting. We provided scoping assistance, drafted and disseminated surveys to hundreds of suppliers, gathered and compiled information from internal and external sources within a custom-built database, and assisted with reporting. At the end of the project, we also provided a due diligence, audit-ready package documenting the processes, assumptions, and decisions made within the project.
Comments on Proposed PFAS Standards in Groundwater. Gradient provided written and oral testimony on behalf of a client to a state pollution control board regarding proposed amendments to groundwater quality standards by the state’s environmental protection agency for six different PFAS. We commented on the agency’s methodology for selecting toxicity values for each of the six PFAS.
PFAS Fate and Transport Assessment at a Municipal Solid Waste Landfill. To support an administrative hearing regarding a landfill expansion permit, Gradient evaluated potential impacts to groundwater and surface water quality near the landfill. We compared chemical concentrations in landfill leachate, groundwater monitoring wells, and nearby surface water with regulatory benchmarks. We used multiple lines of evidence, including an evaluation of the effectiveness of the landfill liner system and temporal evolution of PFAS concentrations in leachate, to estimate the scale of potential surface water impacts if the landfill was expanded.
PFAS Source Evaluation and Forensics. Gradient conducted site research and evaluated the composition and extent of PFAS present at multiple locations throughout the US. Our evaluation included a review of PFAS source characteristics, and fate and transport of PFAS from industrial facilities, landfills, and fire training areas to soil, groundwater, surface water, and sediment. Gradient also evaluated PFAS synthesis process chemistry, compounds associated with specific processes (e.g., electrochemical fluorination [ECF] and telomerization), and changes in chemical characteristics due to environmental mechanisms to forensically draw conclusions regarding the sources of PFAS being observed in environmental samples.
PFAS State of Knowledge. Gradient researched the scientific state of knowledge and history of PFAS analytical chemistry method development for environmental and biological matrices, ecotoxicity, and bioaccumulation. We developed historical timelines and documented the growth in the scientific knowledge based on a review of the scientific literature, public disclosures, and technical reports. These reviews were critical in understanding data quality standards relevant for different analytical methods, matrices, and time periods, as well as the scientific evolution of PFAS ecotoxicity and bioaccumulation characterization.
Testing and Validating PFAS Product Contents. Gradient provided technical support for PFAS product testing, risk assessment, and regulatory compliance for multiple products. We developed sampling and analysis plans, selected testing laboratories, validated analytical results, and interpreted those results.
Assessment of Human Health Risks from Alleged PFAS in Oil and Gas Operations. Gradient evaluated allegations of PFAS use in hydraulic fracturing of unconventional natural gas wells and potential health risks. We assessed the evidence behind claims of PFAS presence in these activities, evaluated the potential for releases to occur, and characterized the transport and fate of released materials in the context of existing regulations. We also evaluated the epidemiology and experimental animal data on various health outcomes and assessed the consistency of research findings and their relevance to human health risk assessment.
In the News:
Another Deadline Extension for PFAS Data Reporting and Recordkeeping Under the Toxic Substances Control Act: Submission Period – May 12, 2025
California Department of Toxic Substances Control Releases Draft 2024-2026 Safer Consumer Products Work Plan – June 11, 2024
