Environmental Forensic Investigation of PFAS Migration from Historical Industrial Operations into Groundwater, Surface Water, and Public Drinking Water Systems
Project Overview
Per- and polyfluoroalkyl substances (PFAS) have become one of the most significant emerging contaminants confronting environmental scientists, regulators, utilities, and industrial facilities. Because many PFAS compounds are highly persistent, mobile in groundwater, resistant to conventional wastewater treatment, and capable of bioaccumulating in environmental media, investigations often require multidisciplinary evaluations integrating environmental chemistry, hydrogeology, contaminant fate and transport, engineering, toxicology, exposure assessment, and environmental forensic science (Buck et al., 2011; Cousins et al., 2020).
RoseyFields was retained to perform an independent environmental forensic evaluation involving historical industrial PFAS releases associated with a large manufacturing operation. The objective of the investigation was to reconstruct historical PFAS source areas, evaluate multiple environmental release mechanisms, characterize contaminant migration through soil, groundwater, surface water, and engineered water management systems, and assess potential impacts to surrounding environmental receptors and public drinking water supplies. Rather than focusing on a single release mechanism, the investigation evaluated the cumulative influence of decades of industrial activities, wastewater management practices, waste disposal operations, stormwater controls, and hydrogeologic conditions that could contribute to regional PFAS occurrence.
The investigation required integration of historical operational records, regulatory information, hydrogeologic data, groundwater monitoring results, surface water sampling, drinking water system information, and environmental chemistry. Particular emphasis was placed on differentiating potential primary source areas from secondary transport mechanisms, evaluating groundwater flow directions, assessing surface water interactions, and understanding how historical waste management practices could influence long-term PFAS migration. Because PFAS compounds exhibit unique environmental behavior compared with traditional contaminants, conventional assumptions regarding degradation and attenuation were carefully evaluated using current scientific understanding.
An important component of the forensic assessment involved evaluating how multiple environmental pathways interacted over time. Historical wastewater discharges, landfill disposal practices, biosolids management, stormwater conveyance systems, groundwater recharge, and hydraulic connections between surface water and aquifers were considered together rather than independently. This systems-based approach provides a more scientifically robust understanding of PFAS transport than evaluating individual environmental media in isolation and is increasingly recognized as best practice in complex environmental forensic investigations (ITRC, 2024; U.S. EPA, 2024).
The project also required assessment of potential exposure pathways extending beyond the immediate industrial property. Public water systems, groundwater resources, connected surface waters, and downstream environmental receptors were evaluated to understand how historical releases could migrate through interconnected hydrologic systems over extended periods. Such investigations require careful consideration of contaminant persistence, groundwater flow dynamics, engineered water infrastructure, and historical operational changes that may influence present-day environmental conditions.
By integrating hydrogeology, environmental chemistry, contaminant fate and transport, engineering controls, analytical chemistry, and environmental forensic reconstruction, the investigation developed a comprehensive conceptual site model capable of supporting scientific evaluation of PFAS occurrence while identifying data gaps, refining potential source areas, and informing future environmental decision-making. This multidisciplinary approach exemplifies the type of complex environmental forensic investigations increasingly required for emerging contaminants and demonstrates the value of combining multiple scientific disciplines when evaluating historical industrial contamination (Brusseau, 2018; National Academies of Sciences, Engineering, and Medicine, 2022).
Chemicals of Concern
The primary chemicals evaluated during this investigation were per- and polyfluoroalkyl substances (PFAS), a diverse class of synthetic fluorinated compounds widely used in industrial manufacturing because of their exceptional resistance to heat, water, oil, and chemical degradation. Their strong carbon-fluorine bonds make PFAS highly persistent in the environment, leading to their designation as “forever chemicals.” Unlike many conventional contaminants, PFAS generally resist biological degradation and can remain in soil, groundwater, sediments, and surface water for decades after their original release (Buck et al., 2011; Cousins et al., 2020).
The investigation primarily focused on several widely studied PFAS compounds that are commonly associated with historical industrial activities. Perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) received particular attention because they have historically been among the most extensively manufactured PFAS compounds and are frequently detected at industrial facilities worldwide. Both compounds exhibit exceptional mobility in groundwater, persistence in aquatic environments, and bioaccumulative potential. Numerous toxicological and epidemiological studies have associated long-term exposure with adverse health outcomes, prompting increasingly stringent regulatory standards and widespread environmental investigations (ATSDR, 2021; U.S. EPA, 2024).
Additional PFAS compounds identified within the analytical datasets included shorter-chain fluorinated compounds such as perfluorobutanoic acid (PFBA) and perfluorobutane sulfonate (PFBS), along with intermediate-chain compounds including perfluorohexane sulfonate (PFHxS). Although these compounds generally bioaccumulate less than longer-chain PFAS, they often exhibit greater mobility in groundwater due to reduced sorption to soil organic matter. Consequently, shorter-chain PFAS can migrate considerable distances through aquifers and may become widespread within regional groundwater systems once released (ITRC, 2024).
A distinguishing characteristic of PFAS contamination is that environmental releases rarely involve a single compound. Instead, industrial operations frequently produce complex mixtures containing multiple PFAS with differing physical and chemical properties. These compounds vary in chain length, functional groups, environmental mobility, partitioning behavior, persistence, and toxicological characteristics. Evaluating the complete PFAS fingerprint, rather than focusing solely on individual analytes, provides valuable information for source attribution and improves understanding of contaminant migration pathways within complex environmental systems (Buck et al., 2011).
The investigation also evaluated how PFAS interact with engineered wastewater systems and environmental media. Unlike many organic contaminants, conventional wastewater treatment processes generally do not destroy PFAS. Instead, treatment often redistributes these compounds between treated effluent, residual biosolids, and other waste streams. Consequently, wastewater treatment facilities may function as secondary transport mechanisms rather than complete removal systems. Historical disposal or beneficial reuse of biosolids can therefore create additional pathways for PFAS migration into soils, groundwater, and nearby surface waters if contaminated residuals are managed outside the original industrial source area (Lindstrom et al., 2011; Washington et al., 2010).
Because PFAS possess diverse transport characteristics, the investigation evaluated contaminant occurrence across multiple environmental media, including groundwater, surface water, soils, stormwater management features, and engineered water infrastructure. This multimedia approach is particularly important because PFAS migration is governed not only by groundwater flow but also by surface water interactions, infiltration, engineered drainage systems, and historical waste management practices. Understanding these interconnected transport mechanisms is essential for accurately reconstructing historical releases, identifying potential source areas, evaluating exposure pathways, and supporting scientifically defensible environmental forensic conclusions (Brusseau, 2018; ITRC, 2024).
Methods
A multidisciplinary environmental forensic investigation was conducted to evaluate the historical release, migration, and environmental behavior of PFAS associated with industrial manufacturing operations. The investigation integrated environmental chemistry, hydrogeology, groundwater modeling, surface water hydrology, environmental engineering, contaminant fate and transport, analytical chemistry, toxicology, and exposure assessment to develop a scientifically supported conceptual understanding of PFAS occurrence throughout the surrounding environment. Rather than relying on a single dataset, multiple independent lines of evidence were synthesized using a weight-of-evidence approach to evaluate potential source areas, reconstruct historical release mechanisms, characterize contaminant migration, and assess potential exposure pathways (ASTM International, 2021; U.S. EPA, 2024).
The investigation began with a comprehensive review of historical operational information, environmental monitoring records, engineering documentation, regulatory reports, and publicly available environmental databases. Historical manufacturing practices, wastewater management systems, waste disposal activities, stormwater infrastructure, and process modifications were evaluated to identify potential mechanisms through which PFAS may have entered the environment. This historical reconstruction provided the foundation for developing a conceptual site model that identified potential primary source areas, secondary transport mechanisms, and the environmental processes governing long-term contaminant migration (Interstate Technology & Regulatory Council [ITRC], 2024; Cousins et al., 2020).
Hydrogeologic evaluations were performed to characterize regional groundwater flow, aquifer properties, hydraulic gradients, recharge conditions, and hydraulic connections between groundwater and adjacent surface water bodies. Geological mapping, groundwater elevation measurements, monitoring well data, and available hydrogeologic investigations were integrated to evaluate contaminant migration within both shallow and deeper groundwater systems. Particular emphasis was placed on understanding how groundwater flow direction, aquifer heterogeneity, recharge variability, and surface water interactions influence the long-term transport of highly mobile PFAS compounds. Evaluating these hydrogeologic processes is essential for accurately interpreting contaminant distributions and distinguishing potential source areas from downgradient migration (Freeze & Cherry, 1979; Fetter, 2018).
Environmental monitoring data from groundwater, surface water, soils, drinking water systems, and other available environmental media were reviewed to characterize PFAS occurrence throughout the study area. Historical analytical results were evaluated to identify concentration trends, compare contaminant fingerprints among environmental media, assess temporal changes in groundwater quality, and evaluate whether observed contaminant distributions were consistent with expected contaminant fate and transport processes. Where appropriate, statistical evaluations, quality assurance documentation, duplicate samples, laboratory qualifiers, and detection frequency analyses were incorporated to improve confidence in the interpretation of environmental monitoring results while minimizing uncertainty associated with isolated detections or analytical variability (U.S. EPA, 2009; ASTM International, 2021).
Finally, engineering evaluations, hydrogeologic analyses, environmental chemistry, groundwater and surface water monitoring, contaminant fingerprinting, toxicological literature, and exposure assessment were integrated into a comprehensive conceptual site model describing the complete source-to-receptor pathway. This multidisciplinary framework allowed the investigation to evaluate historical industrial releases, contaminant persistence, groundwater migration, surface water transport, wastewater management practices, and potential human exposure using accepted environmental forensic methodologies. By integrating multiple scientific disciplines, the investigation provides a technically rigorous foundation for environmental consulting, regulatory investigations, remediation planning, environmental due diligence, and expert witness services involving complex PFAS contamination scenarios (National Academies of Sciences, Engineering, and Medicine, 2022; Brusseau, 2018).
Results
The environmental forensic investigation demonstrated that multiple independent lines of scientific evidence supported a conceptual model in which historical industrial activities contributed to the release of PFAS into interconnected environmental media through multiple transport mechanisms operating over extended periods. Rather than identifying a single release pathway, the investigation demonstrated that the observed environmental distribution was more consistent with cumulative releases associated with historical manufacturing operations, wastewater management practices, stormwater conveyance systems, and long-term contaminant migration within regional hydrogeologic systems. Integrating environmental chemistry, groundwater investigations, engineering evaluations, historical operational information, and analytical data provided a scientifically robust framework for understanding the occurrence and movement of PFAS throughout the study area (U.S. EPA, 2024; Interstate Technology & Regulatory Council [ITRC], 2024).
Hydrogeologic analyses demonstrated that groundwater represented one of the principal pathways for long-term contaminant migration. Evaluation of groundwater elevations, hydraulic gradients, aquifer characteristics, and monitoring data indicated that PFAS movement generally followed established groundwater flow patterns while being influenced by local hydrogeologic heterogeneity and hydraulic connectivity between shallow and deeper water-bearing units. The investigation further demonstrated that groundwater migration could not be evaluated independently of surrounding surface water systems because hydraulic interactions between streams, drainage features, wetlands, and aquifers influenced contaminant transport and distribution throughout the study area. Developing an accurate conceptual hydrogeologic model was therefore essential for interpreting environmental monitoring data and evaluating potential source attribution (Freeze & Cherry, 1979; Fetter, 2018).
Evaluation of environmental monitoring data demonstrated that PFAS occurred across multiple environmental media rather than being confined to a single compartment of the environment. Groundwater, surface water, and other sampled media exhibited contaminant distributions that were consistent with the environmental persistence and mobility of PFAS described in the scientific literature. The investigation also found that evaluating PFAS fingerprints, concentration gradients, and the relative distribution of individual compounds provided considerably greater insight into contaminant sources and transport mechanisms than evaluation of individual analytes alone. This fingerprinting approach strengthened source attribution by allowing environmental professionals to compare chemical signatures across multiple environmental media and potential release pathways (Buck et al., 2011; Cousins et al., 2020).
Engineering evaluations further demonstrated that wastewater management systems, stormwater infrastructure, and historical waste handling practices may influence the long-term movement of PFAS through both engineered and natural environmental pathways. Because conventional wastewater treatment processes generally redistribute rather than destroy PFAS, the investigation highlighted the importance of evaluating the complete water management system, including wastewater treatment, residual solids management, stormwater conveyance, and groundwater recharge, when reconstructing historical contaminant releases. Considering these interconnected pathways provided a more comprehensive understanding of contaminant migration than evaluating individual environmental systems independently (Lindstrom et al., 2011; U.S. EPA, 2024).
Finally, the investigation demonstrated the value of integrating environmental chemistry, hydrogeology, engineering, analytical chemistry, toxicology, contaminant fate and transport, and environmental forensics within a multidisciplinary weight-of-evidence framework. No individual dataset alone fully characterized the occurrence or migration of PFAS; however, combining historical operational information, groundwater and surface water monitoring, hydrogeologic analyses, contaminant fingerprinting, engineering evaluations, and peer-reviewed scientific literature produced a scientifically defensible conceptual site model describing the complete source-to-receptor pathway. This integrated approach provides a strong technical foundation for environmental consulting, regulatory investigations, remediation planning, environmental due diligence, and expert witness evaluations involving complex PFAS contamination and other emerging environmental contaminants (National Academies of Sciences, Engineering, and Medicine, 2022; ASTM International, 2021).
Conclusions
This environmental forensic investigation demonstrated the importance of evaluating PFAS contamination using a multidisciplinary scientific framework that integrates environmental chemistry, hydrogeology, groundwater and surface water investigations, engineering, contaminant fate and transport, analytical chemistry, exposure assessment, and environmental forensic science. Because PFAS are highly persistent, mobile, and capable of migrating through multiple interconnected environmental media, evaluating only a single environmental pathway provides an incomplete understanding of contaminant behavior. By synthesizing multiple independent lines of evidence, the investigation developed a scientifically supported conceptual site model describing the long-term movement of PFAS from historical industrial activities through groundwater, surface water, engineered water management systems, and potential human exposure pathways (U.S. EPA, 2024; Interstate Technology & Regulatory Council [ITRC], 2024).
The investigation demonstrated that understanding PFAS migration requires evaluating the interaction between industrial operations, wastewater management practices, hydrogeologic conditions, groundwater flow systems, and surface water hydrology rather than considering these processes independently. Engineering evaluations and hydrogeologic analyses showed that historical releases may be influenced by multiple transport mechanisms operating simultaneously over extended periods, while environmental monitoring data demonstrated the importance of interpreting contaminant occurrence within the context of regional groundwater flow, hydraulic connectivity, and contaminant persistence. This integrated systems approach provides a more scientifically defensible evaluation than investigations relying solely on individual sampling events or isolated environmental datasets (Freeze & Cherry, 1979; Fetter, 2018).
The investigation further highlighted the importance of chemical fingerprinting and multimedia environmental assessment for source attribution. Evaluating the distribution of multiple PFAS compounds across groundwater, surface water, soils, and engineered water systems provides substantially greater insight into contaminant sources and migration pathways than evaluating individual analytes alone. Integrating analytical chemistry with hydrogeologic interpretation, engineering evaluations, and contaminant fate and transport principles reduces uncertainty while improving confidence in identifying historical release mechanisms and understanding long-term environmental behavior. As regulatory standards for PFAS continue to evolve, comprehensive environmental forensic investigations will remain essential for supporting scientifically sound environmental decision-making and effective risk management (Buck et al., 2011; Cousins et al., 2020).
This case study illustrates the growing role of environmental forensic science in addressing complex contamination involving emerging contaminants whose behavior spans multiple environmental media and extends over decades of industrial operation. By integrating environmental chemistry, hydrogeology, engineering, analytical chemistry, toxicology, exposure science, groundwater modeling, and contaminant fate and transport, RoseyFields provides scientifically rigorous evaluations capable of addressing challenging environmental investigations involving PFAS and other persistent contaminants. These multidisciplinary investigations support environmental consulting, regulatory investigations, remediation planning, environmental due diligence, and expert witness services through objective, evidence-based scientific analyses that are consistent with accepted environmental science and current regulatory guidance (National Academies of Sciences, Engineering, and Medicine, 2022; ASTM International, 2021).
This investigation was conducted under the direction of Dr. Paul Rosenfeld, an environmental scientist and environmental forensic expert with extensive experience in PFAS investigations, groundwater and surface water contamination assessment, source attribution, contaminant fate and transport, exposure assessment, and environmental litigation support. Dr. Rosenfeld’s work focuses on complex environmental contamination matters involving historical industrial releases, PFAS migration through groundwater, surface water, stormwater systems, wastewater infrastructure, soils, and public drinking water supplies, as well as the evaluation of long-term multimedia exposure pathways affecting surrounding communities. His expertise includes reconstructing historical release mechanisms through the integration of hydrogeology, groundwater modeling, surface water hydrology, environmental chemistry, contaminant fingerprinting, wastewater and stormwater engineering, toxicology, exposure science, and regulatory analysis to determine whether industrial operations and water management practices are consistent with observed environmental conditions and potential human health impacts. Through RoseyFields LLC, Dr. Rosenfeld provides environmental forensic analysis, environmental due diligence, regulatory and compliance support, remediation evaluation, toxic tort and personal injury case assessment, and expert witness testimony involving PFAS contamination, industrial wastewater releases, groundwater and surface water migration, public drinking water impacts, and long-term environmental and human health risks associated with persistent contaminants.
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