PFAS in Water: Why We’re Missing 96% of the Problem
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- Video: Concentrating on Chromatography: PFAS in Water: Why We’re Missing 96% of the Problem
🎤Dr. Leigh Terry (University of Alabama)
In this episode of Concentrating on Chromatography, we sit down with Dr. Leigh Terry from the University of Alabama to explore one of the biggest challenges in environmental analysis today: understanding—and accurately measuring—PFAS in water systems.
While most regulatory methods focus on a small number of compounds like PFOA and PFOS, there may be thousands of PFAS compounds in the environment—and much of that burden goes undetected.
In this episode, we cover:
- Why PFAS are called “forever chemicals” (and why that label is evolving)
- The limitations of targeted LC-MS/MS methods
- What the fluorine mass balance problem reveals about PFAS destruction
- How combustion ion chromatography (CIC) helps measure total organofluorine
- Why “99.99% removal” doesn’t always mean what you think
- Where PFAS actually end up in wastewater treatment systems
- The most effective technologies for PFAS removal today
- Why drinking water may only account for ~20% of total PFAS exposure
Key Insight:
Even when analyzing dozens of PFAS compounds, researchers may only be capturing a small fraction of total organic fluorine—raising major questions about how we monitor and regulate these contaminants.
Video Transcription
In this episode of Concentrating on Chromatography, Dr. Leigh Terry discusses PFAS contamination in drinking water, the analytical challenges associated with measuring these compounds, current treatment technologies, and future directions for monitoring and regulation. The conversation highlights how analytical chemistry, environmental engineering, and public health intersect in addressing one of today's most discussed classes of emerging contaminants.
Understanding PFAS and Their Significance
The University of Alabama Water Quality Research Center
Dr. Leigh Terry is part of the University of Alabama's Center for Water Quality Research. The center operates an analytical laboratory focused on drinking water quality and the detection of contaminants at extremely low concentrations.
The laboratory specializes in:
- Drinking water analysis
- Organic contaminants
- Emerging contaminants
- PFAS monitoring
- Water quality research
Their work supports both research initiatives and practical solutions for water utilities and environmental agencies.
Why Focus on PFAS?
Although PFAS compounds have existed since the 1940s, public awareness has increased dramatically only in recent years.
According to Dr. Terry, several factors contributed to the rapid growth of PFAS research:
- Increased media attention
- New regulatory initiatives
- Growing evidence of human exposure
- Expanding research opportunities
- Greater understanding of potential health risks
PFAS are not new contaminants. Rather, society is only beginning to understand their prevalence in the environment and their potential impacts on human health.
The Development of Standardized PFAS Methods
One major advancement in PFAS analysis has been the development of standardized EPA methods.
These methods allow:
- Consistent testing procedures
- Comparable results between laboratories
- Regulatory monitoring
- Reliable data interpretation
Dr. Terry notes that many of these standardized approaches began appearing around 2018–2019, providing a common framework for analytical laboratories and researchers.
How Large Is the PFAS Universe?
Many people are familiar with PFOA and PFOS, two of the most heavily studied PFAS compounds. However, these represent only a small fraction of the broader PFAS family.
PFOA and PFOS are often referred to as:
- Legacy PFAS compounds
- Original PFAS contaminants
- Early commercial PFAS chemicals
The challenge is that even minor modifications to molecular structure create entirely new PFAS compounds.
Researchers estimate:
- Thousands of PFAS compounds exist
- Some estimates exceed 10,000 compounds
- Exact numbers depend on how PFAS are defined
Scientific debate continues regarding classification and definition, making precise counting difficult.
Why PFAS Are Called "Forever Chemicals"
Dr. Terry notes that the phrase "forever chemicals" has become widely used, although she suggests the terminology could benefit from rebranding.
PFAS persistence results from two key chemical properties.
1. Amphiphilic Structure
PFAS molecules contain:
- A water-loving (hydrophilic) head group
- A water-repelling (hydrophobic) fluorinated tail
This unusual combination allows PFAS to partition between:
- Water
- Solids
- Air-water interfaces
- Foam
Unlike many organic compounds, PFAS can interact effectively with multiple environmental phases.
2. Extremely Strong Carbon–Fluorine Bonds
The carbon–fluorine bond is among the strongest bonds in organic chemistry.
As Dr. Terry explains:
- Large amounts of energy are required to break these bonds
- Natural degradation processes are often ineffective
- Destruction can require highly aggressive treatment conditions
These properties make PFAS extremely persistent in both environmental systems and biological organisms.
Toxicity, Regulations, and Environmental Behavior
Understanding PFAS Toxicity
One of the biggest challenges in PFAS regulation is the incomplete understanding of toxicity.
Dr. Terry explains that EPA regulations generally consider three factors:
- Presence in drinking water sources
- Toxicity to humans
- Availability of practical treatment options
While some PFAS compounds are known to be harmful, many others remain insufficiently studied. Furthermore, PFAS often occur as mixtures rather than individual compounds.
This creates important scientific questions:
- What is the toxicity of individual PFAS?
- What is the toxicity of PFAS mixtures?
- How should cumulative exposure be evaluated?
These uncertainties continue to drive active research.
What Happens to PFAS in Wastewater Treatment Plants?
PFAS do not behave like many conventional contaminants.
Rather than remaining fully dissolved in water, they often accumulate at interfaces such as:
- Water-solid interfaces
- Water-air interfaces
- Foam layers
- Biological solids
As a result:
- Some PFAS accumulate in biosolids
- Some partition into foam
- Some remain in treated effluent
Their distribution depends on wastewater composition and treatment processes.
Regulatory Monitoring and Targeted LC-MS Analysis
Current EPA regulations focus on targeted analysis of specific PFAS compounds.
Examples include:
- PFOA
- PFOS
Drinking water regulations currently establish maximum contaminant levels (MCLs) for these compounds at extremely low concentrations.
Advantages of targeted LC-MS analysis include:
- Clearly defined analytes
- Established regulatory limits
- High analytical sensitivity
- Reliable quantitation
However, limitations remain:
- Only a small subset of PFAS is measured
- Many PFAS compounds remain undetected
- Total PFAS burden may be underestimated
As Dr. Terry notes, targeted analysis provides only part of the overall picture.
The Fluorine Mass Balance Problem
One of the most important concepts discussed in the interview is fluorine mass balance.
When PFAS degrade, fluorinated fragments may remain in the environment.
This creates a critical question:
Are treatment technologies truly destroying PFAS, or merely transforming them into shorter-chain PFAS compounds?
To answer this, researchers perform fluorine mass balance calculations using:
- Targeted PFAS analysis
- Fluoride measurements
- Total organic fluorine measurements
A successful destruction process should ultimately convert PFAS into fluoride ions rather than simply producing smaller PFAS molecules.
Advanced Analysis, Treatment Technologies, and Future Directions
Combining Targeted and Bulk Fluorine Measurements
Dr. Terry's group complements targeted LC-MS analysis with measurements of total organic fluorine.
Approaches include:
- Absorbable Organic Fluorine (AOF)
- Extractable Organic Fluorine (EOF)
- Combustion Ion Chromatography (CIC)
In these methods:
- Organic fluorine is captured
- Samples are combusted
- Released fluoride is quantified
This provides insight into total fluorinated content, although contributions may originate from sources beyond PFAS, including pharmaceuticals and consumer products.
Surprising Findings from Combined Analysis
One important finding from wastewater studies was that targeted PFAS measurements accounted for only a small fraction of total organic fluorine.
Dr. Terry reports that:
- Approximately 4% of measured AOF could be explained by targeted PFAS compounds
- The majority of organic fluorine remained unidentified
This suggests that environmental fluorine chemistry is considerably more complex than currently represented by routine monitoring programs.
Preventing PFAS Contamination in the Laboratory
PFAS analysis requires exceptionally strict quality control.
Dr. Terry's laboratory routinely:
- Tests every new batch of SPE cartridges
- Tests carbon tubes before use
- Uses DI water blanks
- Verifies consumables labeled as PFAS-free
- Collects field blanks
- Monitors analytical blanks throughout workflows
These practices help prevent contamination from laboratory materials and consumables, a common challenge in ultra-trace PFAS analysis.
Current PFAS Treatment Technologies
Three technologies currently dominate PFAS removal in drinking water treatment:
- Granular Activated Carbon (GAC)
- Ion Exchange Resins
- Reverse Osmosis (RO)
Selection depends on:
- PFAS concentration
- Water quality
- Local operating conditions
- Utility infrastructure
Although many emerging technologies are being investigated, these remain the most widely implemented solutions.
Membrane Filtration and Pretreatment
Dr. Terry collaborates with colleagues studying membrane-based PFAS treatment.
Her own work focuses on pretreatment through biological filtration.
The strategy involves:
- Removing natural organic matter
- Reducing membrane fouling
- Improving membrane performance
- Extending operational efficiency
This integrated approach demonstrates how multiple treatment technologies can work together to improve PFAS removal.
Regional Monitoring Projects
The University of Alabama team participates in EPA-supported monitoring efforts along the Gulf Coast.
Their observations indicate:
- PFAS rarely occur alone
- Multiple PFAS compounds frequently co-occur
- Contamination often originates from identifiable point sources
Examples include:
- Industrial facilities
- Manufacturing operations
- Military installations
- Carpet manufacturing facilities
Source identification remains a critical component of environmental monitoring programs.
Future Directions for PFAS Monitoring
Looking ahead, Dr. Terry sees several opportunities for improvement.
Desired advances include:
- In situ monitoring technologies
- Portable detection systems
- Reduced analytical complexity
- Lower instrument costs
- Less expensive consumables
- Faster analysis workflows
Current PFAS testing requires substantial expertise, specialized instrumentation, and rigorous quality control, making widespread implementation challenging.
Dr. Terry's Perspective on Long-Term Solutions
When asked what major PFAS challenge she would most like to solve, Dr. Terry offered a broader perspective.
Rather than focusing solely on remediation, she emphasized prevention.
Her view is that society should:
- Better evaluate chemical toxicity before commercialization
- Assess risks before large-scale deployment
- Reduce introduction of harmful compounds into the environment
- Support utilities tasked with contaminant removal
She notes that water utilities often bear the responsibility of removing contaminants they did not create, highlighting the need for broader societal and regulatory support.
Final Thoughts
Dr. Terry encourages consumers to:
- Learn where their drinking water originates
- Read annual water quality reports
- Stay informed about local water quality
- Consider appropriate home filtration where needed
At the same time, she emphasizes confidence in municipal water systems and the importance of continued investment in water quality research, monitoring, and treatment technologies.
Conclusion
PFAS remain one of the most complex challenges in environmental chemistry and water treatment. Through advanced analytical methods such as LC-MS/MS, combustion ion chromatography, fluorine mass balance approaches, and large-scale monitoring programs, researchers like Dr. Leigh Terry are helping improve our understanding of these persistent contaminants.
The interview highlights that solving the PFAS challenge will require a combination of better analytical tools, improved treatment technologies, stronger regulatory frameworks, and a greater emphasis on prevention before contaminants enter the environment.
This text has been automatically transcribed from a video presentation using AI technology. It may contain inaccuracies and is not guaranteed to be 100% correct.
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