Environmental Forensic Investigation of PFAS Drinking Water Contamination, Community Exposure Assessment, Environmental Transport, and Public Water System Evaluation
Project Overview
Per- and polyfluoroalkyl substances (PFAS) have emerged as one of the most significant environmental contamination issues facing public water systems worldwide. Because these synthetic fluorinated compounds are highly resistant to environmental degradation, PFAS released during industrial manufacturing may persist for decades in groundwater, rivers, reservoirs, sediments, and drinking water supplies. Environmental forensic investigations involving PFAS-contaminated water systems require integration of environmental chemistry, hydrogeology, contaminant fate and transport, environmental engineering, exposure assessment, toxicology, historical site reconstruction, and public water system evaluation to characterize contaminant migration, identify exposure pathways, evaluate treatment effectiveness, and assess long-term community exposure. Unlike investigations limited to individual groundwater plumes, PFAS drinking water investigations frequently involve complex interactions among industrial releases, surface water transport, groundwater migration, municipal water treatment, water distribution systems, and human exposure through public drinking water supplies.
This environmental forensic investigation involved a comprehensive technical evaluation of PFAS contamination associated with historical fluorochemical manufacturing and its subsequent migration into public drinking water systems. The investigation integrated historical environmental monitoring data, public water system records, environmental sampling results, engineering evaluations, hydrogeologic information, exposure assessment reports, epidemiological studies, environmental chemistry, and toxicological literature to characterize contaminant occurrence and evaluate potential community exposure. The reviewed documentation included screening-level human exposure assessments, historical environmental monitoring programs, municipal water sampling, river and reservoir investigations, groundwater evaluations, conceptual site models, public water system distribution information, PFAS epidemiological studies, and engineering documentation describing treatment system performance. Collectively, these independent technical resources provided a comprehensive scientific basis for reconstructing contaminant migration from historical industrial sources through multiple environmental media into municipal drinking water systems.
The investigation was conducted using accepted principles of environmental forensics, environmental engineering, hydrogeology, contaminant fate and transport, exposure assessment, environmental chemistry, human health risk assessment, and historical site reconstruction. Particular emphasis was placed on evaluating how PFAS released from industrial operations migrated through interconnected groundwater and surface water systems before entering public water supplies serving surrounding communities. The technical evaluation recognized that characterization of drinking water exposure requires considerably more than measurement of contaminant concentrations alone. Scientifically rigorous exposure assessment also requires understanding the operation of municipal water treatment facilities, distribution system hydraulics, source water characteristics, historical treatment upgrades, blending practices, and long-term changes in water supply management. These engineering considerations directly influence contaminant concentrations delivered to consumers and therefore represent essential components of environmental forensic investigations involving public water systems.
An important objective of the investigation involved reconstructing historical community exposure through integration of environmental monitoring and epidemiological evidence. Historical monitoring programs documented PFAS concentrations in surface water, groundwater, municipal drinking water, sediments, fish tissue, and other environmental media over multiple decades. These environmental data were evaluated together with published epidemiological investigations examining serum PFAS concentrations among residents relying upon contaminated public water supplies. By integrating environmental measurements with biomonitoring and exposure modeling, the investigation developed a scientifically supported framework for evaluating long-term community exposure and assessing how changes in water treatment and source water management influenced human exposure over time. The investigation further considered the effectiveness of advanced treatment technologies—including granular activated carbon (GAC), biologically active carbon (BAC), ion exchange systems, and reverse osmosis—in reducing PFAS concentrations within treated drinking water supplied to affected communities.
Chemicals of Concern
The principal contaminants evaluated during this investigation were perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS), together with other members of the broader family of per- and polyfluoroalkyl substances (PFAS). These synthetic fluorinated compounds have been manufactured since the mid-twentieth century for use in fluoropolymer production, surface coatings, stain-resistant materials, aqueous film-forming foams, food packaging, metal plating, textiles, and numerous industrial applications. Their unique carbon-fluorine bonds impart exceptional thermal and chemical stability, making PFAS resistant to hydrolysis, photolysis, microbial degradation, and many natural environmental transformation processes. Consequently, PFAS released into the environment frequently persist for decades while migrating through groundwater, rivers, lakes, reservoirs, and public drinking water systems. The reviewed technical documentation specifically identified industrial releases, wastewater discharges, air emissions, and historical manufacturing waste streams as important mechanisms through which PFAS entered surrounding environmental systems.
Among the PFAS compounds evaluated, PFOA received particular attention because of its historical use in fluoropolymer manufacturing, widespread environmental occurrence, extensive toxicological database, and documented association with drinking water contamination near fluorochemical manufacturing facilities. Historical environmental monitoring programs measured PFOA concentrations in soils, groundwater, surface water, sediments, municipal drinking water, fish tissue, and other environmental media to characterize contaminant migration and evaluate potential exposure pathways. The reviewed exposure assessments also developed scenario-specific exposure estimates for residents, recreational users, workers, and other potentially exposed populations by integrating measured environmental concentrations with accepted exposure modeling methodologies. These evaluations illustrate the multidisciplinary nature of environmental forensic investigations involving persistent contaminants that migrate through multiple environmental media before reaching human receptors.
The investigation likewise evaluated PFOS, another extensively studied PFAS compound historically used in industrial manufacturing and commercial products. Like PFOA, PFOS exhibits exceptional environmental persistence and bioaccumulation potential and has been detected in drinking water supplies, surface waters, sediments, fish tissue, wildlife, and human serum throughout the world. Environmental monitoring programs included in the reviewed documentation measured PFOS together with other PFAS compounds to evaluate contaminant distributions within rivers, reservoirs, municipal water systems, and treatment facilities. Surface water investigations demonstrated that PFAS may be transported considerable distances downstream from original industrial release locations, emphasizing the importance of watershed-scale investigations rather than limiting environmental evaluations to facility boundaries. Sampling results from the Tennessee River system documented measurable PFOS and PFOA concentrations at multiple upstream, downstream, raw water, finished water, and background sampling locations, illustrating the value of comprehensive monitoring networks for characterizing contaminant transport within large river systems.
The reviewed documentation further recognized that drinking water represents one of the principal human exposure pathways for many PFAS compounds. Environmental investigations therefore evaluated not only contaminant occurrence within source waters but also treatment system performance, municipal distribution systems, water blending practices, and long-term operation of public water utilities. Evaluation of drinking water systems is particularly important because treatment technologies differ substantially in their ability to remove PFAS. Conventional drinking water treatment processes typically provide limited removal of many PFAS compounds, whereas advanced treatment technologies—including granular activated carbon, ion exchange resins, biologically active carbon, and reverse osmosis—may substantially reduce finished water concentrations when properly designed and maintained. Consequently, engineering evaluation of treatment system performance represents an integral component of scientifically rigorous PFAS exposure assessments. Internal technical documentation reviewed during the investigation specifically identified implementation of MIEX treatment, biologically active carbon systems, reverse osmosis upgrades, and water purchasing strategies as factors requiring consideration when reconstructing historical drinking water exposure.
The investigation also incorporated contemporary understanding of PFAS environmental fate and transport. Unlike many conventional organic contaminants, PFAS remain mobile within groundwater while also undergoing long-range transport through rivers, reservoirs, and regional surface water systems. Historical white papers, environmental monitoring programs, and engineering evaluations described contaminant release mechanisms, environmental transport, environmental distribution, human exposure scenarios, and ecological considerations associated with fluorochemical manufacturing. Understanding these environmental processes is essential because present-day contaminant distributions frequently reflect decades of cumulative releases combined with long-term hydrologic transport, water treatment practices, and environmental persistence. Integration of environmental chemistry with hydrogeology and public water engineering therefore provides the scientific foundation necessary for evaluating long-term PFAS contamination affecting municipal drinking water supplies.
Methods
The investigation was conducted using accepted principles of environmental forensics, hydrogeology, environmental engineering, environmental chemistry, contaminant fate and transport, exposure assessment, toxicology, and public water system evaluation. Because PFAS contamination affecting municipal drinking water systems often develops over multiple decades through numerous interconnected environmental pathways, the investigation integrated historical environmental monitoring, engineering documentation, hydrogeologic evaluations, public water system records, exposure modeling, epidemiological studies, toxicological literature, and environmental chemistry into a comprehensive technical framework. Rather than relying upon any individual environmental medium or monitoring program, the investigation synthesized multiple independent datasets to reconstruct contaminant migration, characterize historical community exposure, and evaluate changes in drinking water quality resulting from treatment upgrades and source water management. This multidisciplinary approach is consistent with accepted environmental consulting practice for evaluating widespread PFAS contamination affecting public water supplies.
A primary component of the investigation involved historical site reconstruction. Historical manufacturing records, environmental investigations, regulatory documentation, engineering reports, and historical environmental monitoring programs were reviewed to identify the origin of PFAS releases, characterize historical manufacturing practices, and reconstruct contaminant migration over time. Evaluation of historical operations included review of manufacturing processes, wastewater discharges, air emissions, waste management practices, environmental monitoring programs, and historical remedial actions that influenced PFAS movement throughout surrounding environmental systems. Historical reconstruction provided the scientific foundation necessary to relate present-day environmental conditions to decades of industrial activity and long-term environmental transport.
The investigation relied extensively upon surface water and groundwater investigations to characterize contaminant migration from historical industrial sources to municipal drinking water systems. Environmental monitoring data included sampling of rivers, reservoirs, tributaries, groundwater, municipal water supplies, sediments, fish tissue, and other environmental media. Groundwater evaluations examined hydraulic conditions, groundwater flow directions, contaminant migration pathways, and the interaction between groundwater and adjacent surface water systems. Surface water investigations characterized contaminant transport within major river systems, evaluated downstream migration, and identified public water intakes potentially affected by historical PFAS releases. These investigations demonstrated the importance of evaluating entire watershed systems rather than limiting environmental assessments to individual industrial facilities because PFAS may remain mobile over substantial distances through interconnected hydrologic systems.
An important component of the investigation involved public water system evaluation. Engineering documentation describing municipal water treatment facilities, raw water sources, finished water quality, treatment upgrades, water distribution systems, storage facilities, blending practices, and purchased water supplies was reviewed to understand how PFAS concentrations changed before water reached consumers. Evaluation of treatment system operation included assessment of source water characteristics, treatment performance, operational modifications, and engineering improvements implemented to reduce PFAS concentrations within finished drinking water. The investigation also considered how changes in water treatment technology—including implementation of granular activated carbon (GAC), biologically active carbon (BAC), ion exchange treatment, MIEX systems, and reverse osmosis—altered contaminant concentrations delivered through municipal distribution systems. These engineering evaluations provided important context for interpreting historical exposure because drinking water concentrations often changed substantially following treatment upgrades or modifications to water supply operations.
The technical evaluation further incorporated environmental chemistry and contaminant fate and transport analysis. Historical white papers, environmental monitoring data, and engineering evaluations were reviewed to understand how PFAS migrated through groundwater aquifers, rivers, reservoirs, wastewater systems, sediments, and drinking water infrastructure following environmental release. Particular attention was devoted to the persistence of PFAS, their resistance to environmental degradation, their mobility within aquatic systems, and the physical and chemical mechanisms governing contaminant transport. Evaluation of environmental fate and transport also considered the influence of river flow, reservoir hydraulics, groundwater discharge, sediment interactions, and seasonal hydrologic variability on contaminant distribution. Understanding these environmental processes is essential because historical releases may continue contributing to drinking water contamination decades after original manufacturing activities have ceased.
The investigation also incorporated human exposure assessment using accepted environmental health methodologies. Screening-level human exposure assessments integrated measured environmental concentrations with estimates of drinking water consumption, incidental soil ingestion, recreational water use, fish consumption, dermal contact, inhalation, and other relevant exposure pathways. Rather than focusing exclusively on drinking water, the technical evaluation considered cumulative exposure across multiple environmental media while recognizing that municipal drinking water frequently represented the dominant contributor to long-term community exposure. Exposure assessments also evaluated differing receptor populations, including residents, children, recreational users, workers, and other potentially exposed groups, allowing environmental conditions to be interpreted within the context of realistic human activities and accepted exposure science.
The investigation further reviewed epidemiological studies and biomonitoring information describing PFAS exposure among populations relying upon contaminated public water supplies. Published epidemiological investigations, serum biomonitoring programs, and community exposure studies were evaluated to compare measured environmental concentrations with biological indicators of long-term PFAS exposure. Internal technical evaluations also compared environmental monitoring results with findings from large community health investigations involving drinking water contamination, providing additional scientific context for interpreting historical exposure. Integration of environmental measurements with epidemiological evidence strengthened the technical evaluation by linking environmental contaminant occurrence with established exposure science and published public health research.
Geographic information systems (GIS) and spatial analysis also supported the environmental forensic investigation. Mapping of industrial facilities, river systems, reservoirs, municipal water intakes, treatment plants, distribution networks, and surrounding communities allowed investigators to evaluate contaminant migration across large geographic areas. Spatial analyses helped identify relationships among contaminant sources, environmental transport pathways, water supply infrastructure, and potentially exposed populations while supporting conceptual understanding of contaminant movement throughout the watershed. Integration of GIS with environmental monitoring and hydrogeologic investigations provides a scientifically rigorous framework for evaluating regional drinking water contamination associated with persistent environmental contaminants.
Finally, the investigation employed a weight-of-evidence methodology integrating historical site reconstruction, environmental chemistry, groundwater investigations, surface water monitoring, public water system engineering, exposure assessment, epidemiology, toxicology, and environmental monitoring into a unified environmental forensic assessment. Each category of technical information contributed unique scientific insight regarding contaminant sources, environmental migration, treatment effectiveness, and human exposure. By evaluating these independent datasets collectively rather than in isolation, the investigation reduced uncertainty associated with any individual monitoring program or engineering evaluation and developed a scientifically supported reconstruction of historical PFAS contamination affecting public drinking water systems. This multidisciplinary methodology represents current best practice within environmental consulting, environmental litigation support, expert witness investigations, and environmental forensic science involving widespread PFAS contamination of municipal drinking water supplies.
Results
Review of the available technical documentation demonstrated that comprehensive evaluation of PFAS contamination affecting public drinking water requires integration of environmental chemistry, hydrogeology, environmental engineering, exposure science, epidemiology, and long-term environmental monitoring. Although the reviewed materials encompassed multiple watersheds, numerous municipal water systems, and decades of environmental data, the investigation consistently demonstrated that combining environmental monitoring with engineering evaluations and exposure assessment provides the most scientifically rigorous framework for reconstructing historical community exposure. Collectively, the reviewed screening-level exposure assessments, environmental monitoring programs, public water system investigations, engineering reports, toxicological evaluations, and epidemiological studies established a comprehensive scientific basis for understanding the movement of PFAS from historical industrial sources into municipal drinking water supplies serving surrounding communities.
One of the principal findings of the investigation was that surface water and groundwater functioned as interconnected transport pathways for historical PFAS releases. Environmental monitoring programs documented measurable PFAS concentrations within rivers, reservoirs, tributaries, groundwater, municipal water supplies, sediments, and aquatic biota, demonstrating that contaminants released from industrial operations migrated well beyond facility boundaries through regional hydrologic systems. Rather than remaining localized near manufacturing areas, PFAS were transported downstream through major river systems and subsequently entered public water supplies serving numerous communities. These findings reinforce a fundamental principle of environmental forensics: persistent contaminants frequently migrate through multiple interconnected environmental media, requiring watershed-scale investigations rather than evaluations limited to individual industrial properties.
The investigation further demonstrated the importance of historical environmental monitoring in reconstructing long-term contaminant migration. Monitoring programs conducted over multiple years documented changing PFAS concentrations within raw water, finished drinking water, groundwater, sediments, and aquatic environments. Long-term environmental records allowed investigators to evaluate temporal trends in contaminant occurrence, identify periods of increasing or decreasing concentrations, and assess how engineering modifications influenced water quality over time. Because PFAS remain environmentally persistent, historical monitoring data provided valuable insight into contaminant behavior that could not be obtained from isolated sampling events alone. Integration of these long-term datasets strengthened the environmental forensic evaluation by establishing continuity between historical releases and present-day environmental conditions.
Another significant finding involved the role of municipal water treatment systems in reducing community exposure. Engineering documentation described implementation of advanced treatment technologies, including granular activated carbon (GAC), biologically active carbon (BAC), magnetic ion exchange (MIEX), reverse osmosis, and modifications to water supply operations intended to reduce PFAS concentrations within finished drinking water. The reviewed engineering evaluations demonstrated that treatment system upgrades and operational changes substantially influenced contaminant concentrations delivered to consumers. These findings emphasize that evaluation of community exposure requires understanding not only environmental contamination but also the engineering performance of public water systems responsible for treating and distributing drinking water. Historical reconstruction of treatment system improvements therefore represents a critical component of exposure assessment because consumer exposure frequently changes following implementation of improved treatment technologies.
The investigation also demonstrated the value of screening-level human exposure assessments for evaluating multiple exposure pathways simultaneously. Rather than considering drinking water exposure in isolation, the reviewed technical evaluations incorporated groundwater, surface water, fish consumption, incidental soil ingestion, recreational activities, dermal contact, and other potential exposure pathways into cumulative exposure assessments. Although municipal drinking water represented the principal exposure pathway for most community members, consideration of multiple environmental media provided a more comprehensive understanding of overall PFAS exposure. These findings illustrate the importance of integrated exposure science in environmental forensic investigations involving persistent contaminants distributed across numerous environmental compartments.
Review of the epidemiological literature and biomonitoring information further demonstrated that community exposure investigations benefit from integrating environmental measurements with biological evidence of exposure. The reviewed materials compared measured PFAS concentrations in drinking water with serum PFAS concentrations reported in published epidemiological investigations, allowing environmental monitoring data to be interpreted within the context of documented human exposure. Technical presentations comparing environmental concentrations with findings from the C8 Health Project further illustrated how biomonitoring and epidemiological research can complement environmental investigations by providing independent evidence regarding long-term human exposure associated with contaminated public water supplies. Rather than relying solely upon environmental sampling, integration of biomonitoring data strengthened the scientific foundation supporting exposure reconstruction.
The investigation additionally demonstrated the importance of engineering evaluations and environmental chemistryin interpreting monitoring data. Historical white papers, engineering reports, and environmental monitoring consistently recognized that PFAS exhibit exceptional environmental persistence, remain highly mobile within aquatic systems, and resist many conventional drinking water treatment processes. These characteristics explain why historical industrial releases continued influencing water quality long after original manufacturing activities had changed or ceased. Evaluation of environmental chemistry alongside engineering system performance therefore provided a more complete understanding of contaminant occurrence than environmental monitoring alone.
Collectively, the reviewed documentation demonstrated that environmental forensic investigations involving PFAS-contaminated drinking water benefit substantially from integrating hydrogeology, environmental chemistry, engineering analysis, public water system evaluation, exposure assessment, toxicology, epidemiology, and long-term environmental monitoring into a unified scientific framework. No individual dataset independently described the complete history of contamination or community exposure. However, when environmental monitoring, treatment system evaluations, watershed investigations, exposure assessments, epidemiological studies, and engineering documentation were considered together, they provided a scientifically supported reconstruction of contaminant migration and long-term public exposure.
Conclusions
The available technical documentation provides a comprehensive scientific foundation for evaluating PFAS contamination affecting public drinking water systems using accepted principles of environmental forensics, hydrogeology, environmental engineering, contaminant fate and transport, environmental chemistry, exposure assessment, toxicology, and historical site reconstruction. Although PFAS investigations frequently involve multiple decades of industrial operations and complex regional water systems, integration of multiple independent scientific datasets allows contaminant migration and community exposure to be reconstructed using well-established environmental methodologies.
The investigation demonstrated that historical environmental monitoring, groundwater investigations, surface water evaluations, public water system engineering, exposure assessments, epidemiological evidence, and toxicological information each contribute unique scientific insight regarding contaminant occurrence and human exposure. When evaluated collectively through a weight-of-evidence framework, these independent datasets provide a more complete and scientifically defensible understanding of environmental contamination than reliance upon any individual monitoring program or engineering evaluation.
Review of the available documentation also illustrates the importance of evaluating drinking water contamination within the broader context of watershed hydrology and municipal water system operation. Environmental investigations that integrate contaminant transport, treatment system performance, water distribution infrastructure, and exposure science provide a more technically accurate assessment of community exposure than evaluations based solely upon measured drinking water concentrations. This multidisciplinary perspective is particularly important for persistent contaminants such as PFAS, whose environmental behavior is strongly influenced by regional hydrology, engineering controls, and long-term environmental persistence.
More broadly, this investigation demonstrates how modern environmental consulting integrates hydrogeology, environmental chemistry, environmental engineering, contaminant fate and transport, exposure assessment, toxicology, epidemiology, public water system engineering, and historical reconstruction to evaluate complex PFAS contamination affecting municipal drinking water supplies. These multidisciplinary investigations provide scientifically supported evaluations of contaminant migration, community exposure, and engineering performance while remaining grounded in objective technical analysis, peer-reviewed science, and accepted environmental engineering methodologies.
This investigation was conducted under the direction of Dr. Paul Rosenfeld, an environmental scientist, environmental forensic expert, and exposure assessment specialist with more than twenty-five years of experience evaluating complex environmental contamination involving drinking water supplies, groundwater systems, industrial manufacturing, and persistent environmental contaminants. Throughout his career, Dr. Rosenfeld has investigated contamination involving PFAS, petroleum hydrocarbons, volatile organic compounds, metals, pesticides, asbestos, combustion products, ethylene oxide, and numerous other contaminants affecting public water systems, groundwater resources, occupational environments, and surrounding communities.
References
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