March 2025 - MABA Biosolids Spotlight 

Provided to MABA members by Bill Toffey, Effluential Synergies, LLC 

SPOTLIGHT on Dr. Linda S. Lee and Her Research Group

“Go slow on the regulations. Go fast on the research.”  

This is Dr. Linda Lee’s consistent message to regulators, policymakers, business leaders and agency employees, and to the public. One of her PFAS anecdotes is the failure of the Air Force to address the widespread detection of PFAS in groundwater at a military site when first brought to their attention. Per- and poly-fluoroalkyl substances, or PFAS, were intentionally put in aqueous film-forming foams (AFFFs) in the 1960s to facilitate extinguishing hydrocarbon fires fast. At the time, Dr. Lee explains, PFAS compounds were not understood to persist nor that they could lead to adverse health effects. Slow response to their presence has led to decades of continued discharge of a class of recalcitrant fluorinated compounds during firefighting training at hundreds of military bases as well as airports, which has contributed to much of the widespread contamination we currently face. Dr. Lee has witnessed how this has been followed now by numerous regulations, sparking expensive actions and existential threats to many corners of society, no less to the corner biosolids practitioners inhabit. Dr. Lee uses this story to remind audiences, also, to be wary of quick substitute formulations not yet subjected to research, which in time may show up as hazardous.

Dr. Linda S. Lee is a Distinguished Professor of Agronomy at Purdue University, with a joint appointment in Environmental & Ecological Engineering (EEE). Renowned nationally and internationally, Dr. Lee is a leading authority on environmental chemistry, focusing particularly on the fate and exposure aspects of contaminants, with a significant emphasis on per- and poly-fluoroalkyl chemicals (PFAS) over the past two decades.  Her contributions to environmental chemistry and PFAS research have positioned her as a key figure in addressing pressing environmental challenges.

Linda S Lee, PhD, Distinguished Professor of Agronomy at Purdue University

Dr. Lee’s work is characterized by a commitment to bridge the gap between scientific research and practical application. She excels in conducting both laboratory and field-scale studies that directly address stakeholder needs, translating complex scientific findings into actionable strategies for regulatory agencies, environmental managers, farmers, and homeowners. Her dedication to stakeholder engagement is evident in her active participation in congressional briefings, her support for farmers navigating PFAS-impacted agriculture, and her work with regulatory bodies.

A strong advocate for collaboration, Dr. Lee encourages interdisciplinary research, fostering partnerships across various fields, including human health effects, ecotoxicity, and green manufacturing. Her extensive publication record, comprising nearly 200 papers within top environmental chemistry journals, underscores her significant contributions to the field. Her earlier research encompassed polyaromatic hydrocarbons, pesticides, antibiotics, hormones, and metalloids. Dr. Lee holds a few patents related to environmental remediation technologies.   

Her research program is driven by user-inspired challenges. This brought her to focus on PFAS and unregulated organic chemical (UOC) fate, mitigation, and remediation in various systems. Dr. Lee's group was among the first in the U.S. to focus on PFAS behavior, beginning in the mid-2000s. Her work has been instrumental in understanding PFAS environmental occurrence, soil affinity, and microbial degradation. She developed and optimized analytical tools for detecting PFAS at increasingly lower concentrations, contributing to a deeper understanding of PFAS transport and transformation.  Her early research revealed the role of PFAS structure in solubility and sorption and microbial transformation of precursor PFAS that can lead to PFOA and PFOS. These findings were among those that informed EPA's efforts to reduce fluorotelomer alcohol residuals and to phase out bioaccumulative long-chain PFAS. Her biotransformation studies also highlighted the challenge for bioremediation strategies to exacerbate PFAS issues.  Her research has since moved from lab-based to field-based studies and with projects, and looking beyond PFAS, as her current research projects include EPA-funded research grant to the Water Research Foundation: Unregulated Organic Chemicals in Biosolids: Prioritization, Fate and Risk Evaluation for Land Applications and collaborating on a SERDP-funded project assessing ecotoxicity of PFAS alternatives.

Field sampling a watershed for PFAS with Dr. Lee in the background supervising her graduate students

Dr. Lee's extensive speaking engagement includes 58 invited talks in the past four years, addressing diverse stakeholder groups. She has delivered keynote addresses at conferences, contributed to NAS initiatives, and advised on regional biosolids studies and EPA panels. She has also advised the State of California on PFAS regulations and pesticide total maximum daily load limits.  She has participated in high-level workshops, including the 2024 USDA workshop on PFAS in agriculture and food systems, and serves on the NAS Committee assisting the USDA in addressing PFAS on agricultural land.  She has presented to diverse audiences, including the Products Stewardship Society and the Wastewater Engineers and Technology Trade (WWETT) Conference, providing critical insights into PFAS regulations and challenges. 

Dr. Lee's research has had tangible impacts on environmental policy and agricultural practices. Her work extends to empowering local emergency planning committees and facilitating discussions on urban soil quality. Her research on PFAS in fast-food packaging influenced legislation in Washington and California, contributing to the phase-out of PFAS use in packaging materials and other consumer products.  Notably, her team's work on hormones in manure led the EPA to a science-based decision against regulating manure applications as a means of controlling natural hormones in the waterways, preventing significant financial burdens on the farming community. Furthermore, her research has enabled farmers to reduce PFAS in food and feed products while maintaining economic viability.   

Education and mentorship are central to Dr. Lee's mission. She has mentored 44 students, with a significant proportion now holding tenured faculty positions, working in chemical and pharmaceutical companies, engineering/consulting firms, and government agencies. She has developed and facilitated numerous educational programs, demonstrating her dedication to enhancing student success. Most of Dr. Lee’s science journal publications have authors from within her group who are PhD students and post docs, as exemplified in these eight 2024 and 2025 papers to date:

• Sources and Pathways of PFAS Occurrence in Water Sources: Relative Contribution of Land-Applied Biosolids in an Agricultural Dominated Watershed

• Evaluating sorbents for reducing per- and polyfluoroalkyl substance mobility in biosolids-amended soil columns

• Understanding the impact of pre-digestion thermal hydrolysis process on PFAS in anaerobically digested biosolids 

• Fate of per- and polyfluoroalkyl substances at a 40-year dedicated municipal biosolids land disposal site

• Per- and polyfluoroalkyl substances behavior: Insights from autothermal thermophilic aerobic digestion - Storage nitrification-denitrification reactors

• Analysis of multi-class unregulated organic compounds in soil and biosolids using LC-MS/MS. Environmental Pollution,

• State of the Science and Regulatory Acceptability for PFAS Residual Management Options: PFAS Disposal or Destruction Options,

• Evaluation of PFAS Extraction and Analysis Methods for Biosolids.

Biosolids practitioners can look forward to these early-career scientists who are lead authors of these papers to be the next generation guiding us through the current PFAS challenge and importantly going on to study “unregulated organic compounds.”  Her group was the cover story in CSA News in November 2022: When Chemicals Go to the Dark Side: The Unintended Consequences of Emerging Contaminants.

The cover of the November 2022 CSA News (the monthly magazine of the tri-societies Crop Science, Soil Science and Agronomy) with two graduate students Lynda Peter and Ariana Lazo taking water samples for PFAS 

Lynda Godwin Peter picture from Purdue University’s spotlight on graduate ag researchers.

Lynda Godwin Peter's Nigerian upbringing, steeped in both science and humanities, fueled her passion for environmental research. She earned her environmental science degree from the University of Benin, focusing on soil science, driven by Nigeria's water contamination challenges. Her master's at Tennessee State University explored heavy metal remediation. Discovering Dr. Linda Lee's work on PFAS at Purdue University, she joined the lab in 2020. Peter was featured in a Purdue “spotlight” on graduate ag research in January 2025 for her PhD research investigation into PFAS, and she is the central image on the cover of the CSA News magazine.  Her focus on PFAS is its movement from biosolids in soil to water sources, quantifying long-term risks using field studies, lab analysis, and modeling. Utilizing advanced instrumentation, she measures PFAS at parts-per-trillion levels, addressing their toxic effects. Peter actively contributes beyond research, representing Purdue's agronomy department in the Graduate Student Senate and serving on the Ag Alumni Board. She has presented at international conferences, published her findings, and mentored undergraduates. As she completes her PhD, Peter aims for a postdoctoral position in PFAS research, aspiring to a faculty role. Outside academia, she pursues gardening, running, drawing, and baking, finding parallels between pie-making and chemistry.

Youn Choi, PhD and Post Doc

Youn Choi is a PhD graduate of Dr. Lee’s group as well, who came back to fill the Analytical Chemist position in her group. Choi has been instrumental to Dr. Lee for enabling her to collaborate with so many groups. She has become an expert in PFAS analytical methods for various media, and particularly in non-target analysis with high resolution mass spectrophotometry.  Dr. Lee says of Choi, “she is my eyes, hands and feet in the daily supervision and mentoring within the lab. She is amazing and does not get enough credit where credit is due. She is instrumental in much of what we are able to do, including a key to supporting much of the PFAS adverse human and biota health effects we serve as collaborators!” 

Caroline Rose Alukkal, PhD and Post Doc

Caroline Rose Alukkal is a Ph.D. scholar in Interdisciplinary Ecological Science & Engineering with the department of Environmental and Ecological Engineering.  With a bachelor's degree in biotechnology engineering and a master's degree in environmental science and engineering, she possesses a diverse wealth of expertise to understand environmental challenges and respond with innovative solutions. Currently, her focus is on quantifying PFAS, with a primary emphasis on wastewater resource recovery facilities (WWRFs) and biosolids for their sustainable management. Alukkal is developing analytical tools for the unknown fluorinated precursors.  She is actively involved in research on technologies for remediate PFAS risk in soils.  Her happiness is rooted in enhancing the quality of the environment and in educating others about its importance.

For more information, contact Mary Baker at [email protected] or 845-901-7905.