Environmental Forensic Investigation of Historical Chemical Releases, Fugitive Dust Transport, and Human Exposure at a Former Industrial Waste Disposal Facility
Project Overview
Historical industrial waste disposal facilities present some of the most complex challenges in environmental forensic science because contaminants may remain in soils, sediments, groundwater, surface water, and airborne dust for decades after disposal activities have ceased. Reconstructing historical contaminant releases requires integrating environmental chemistry, atmospheric science, hydrogeology, engineering, toxicology, exposure science, and environmental modeling to understand how chemicals migrated through multiple environmental media over time. In many cases, incomplete historical records and evolving site conditions require investigators to synthesize numerous independent lines of evidence into a scientifically defensible conceptual site model that explains contaminant sources, transport mechanisms, and potential human exposure pathways (U.S. EPA, 1989; ASTM International, 2021).
RoseyFields conducted a comprehensive environmental forensic investigation involving a former industrial waste disposal facility that historically accepted a variety of municipal and industrial wastes. The objectives of the investigation were to reconstruct historical disposal operations, identify the primary contaminants of concern, evaluate contaminant migration through air and environmental media, develop quantitative estimates of historical human exposure, and assess potential human health risks associated with long-term environmental contamination. The investigation emphasized historical site reconstruction, contaminant fate and transport, air dispersion modeling, environmental sampling interpretation, and quantitative exposure assessment while integrating engineering principles with environmental chemistry and toxicology.
A major focus of the investigation involved evaluating the generation and transport of contaminated fugitive dust during multiple historical phases of site activity. Operational waste handling, heavy equipment movement, soil disturbance, wind erosion, and subsequent recreational use of disturbed soils all represented potential mechanisms for transporting contaminated particulates beyond the disposal area. Because many persistent organic contaminants strongly adsorb to soil particles, evaluating airborne particulate transport was essential for understanding long-term contaminant migration and potential residential exposure. Historical aerial imagery, engineering evaluations, environmental sampling results, contaminant distributions, and atmospheric dispersion modeling were integrated to reconstruct how contaminants may have migrated under changing site conditions throughout several decades of operation and post-operational land use (Cowherd et al., 2006; U.S. EPA, 2017).
In addition to evaluating airborne transport, the investigation examined contaminant occurrence within soils, indoor dust, groundwater, and other environmental media to characterize complete source-to-receptor pathways. Historical environmental monitoring data were evaluated together with toxicological information, exposure assumptions, and statistical analyses to estimate long-term human exposure under representative residential and recreational scenarios. This multidisciplinary approach illustrates how environmental forensic investigations can integrate engineering, environmental chemistry, atmospheric modeling, industrial hygiene, toxicology, epidemiology, and quantitative risk assessment to provide scientifically rigorous evaluations of historical contamination while protecting confidential client information. (ATSDR, 1998; National Academies of Sciences, Engineering, and Medicine, 2013)
Chemicals of Concern
The principal chemicals of concern evaluated during this environmental forensic investigation were polychlorinated biphenyls (PCBs) and polychlorinated dibenzo-p-dioxins and dibenzofurans (commonly referred to collectively as dioxins). These persistent organic pollutants have historically been associated with industrial manufacturing, waste disposal, combustion processes, and chemical production. Their exceptional environmental persistence, strong affinity for soils and organic matter, resistance to natural degradation, and tendency to bioaccumulate make them among the most important contaminants encountered during complex environmental forensic investigations. Even decades after disposal activities cease, these compounds may remain within soils, sediments, surface water, groundwater, and airborne particulate matter, creating long-term opportunities for human and ecological exposure (ATSDR, 1998; WHO, 2016).
Dioxins represent a family of chlorinated organic compounds that are generally formed unintentionally during certain industrial processes and combustion activities involving chlorinated materials. Individual dioxin congeners exhibit varying toxicities, and environmental investigations commonly express results using toxic equivalency (TEQ) methodology, which converts individual congeners into a single toxicity-weighted concentration relative to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), the most toxic member of the group. Because dioxins strongly adsorb to fine soil particles and organic matter while degrading very slowly in the environment, contaminated soils can remain a continuing source of airborne particulate emissions when disturbed by construction activities, wind erosion, recreational use, or other soil-disturbing operations (Van den Berg et al., 2006; U.S. EPA, 2012).
PCBs were also evaluated because they have historically been used in numerous industrial applications, including electrical equipment, hydraulic fluids, plasticizers, heat-transfer systems, and other commercial products. Although their manufacture has been prohibited in many countries for decades, PCBs remain widespread environmental contaminants due to their chemical stability and persistence. Similar to dioxins, PCBs bind strongly to soils, sediments, and suspended particulate matter, allowing contaminated dust to become an important transport mechanism under appropriate environmental conditions. Long-term exposure to PCBs has been associated with developmental effects, immunotoxicity, endocrine disruption, liver toxicity, reproductive effects, and increased risks of certain cancers, making them a frequent focus of environmental investigations involving historical industrial waste disposal (ATSDR, 2000; IARC, 2016).
An important aspect of this investigation involved evaluating how both dioxins and PCBs migrated through multiple environmental media rather than remaining confined to the original disposal area. Historical waste handling activities, heavy equipment operation, exposed soils, wind erosion, and other mechanical disturbances can generate contaminated fugitive dust capable of transporting particle-bound contaminants beyond the source area. Once deposited, these contaminants may accumulate in residential soils, outdoor surfaces, indoor dust, and other environmental media where long-term human exposure may occur through incidental soil and dust ingestion, dermal contact, or inhalation of resuspended particulates. Understanding these interconnected transport mechanisms is essential when reconstructing historical exposure pathways and evaluating contaminant fate and transport over extended periods (Cowherd et al., 2006; U.S. EPA, 2017).
Because both dioxins and PCBs persist for decades while exhibiting similar environmental transport characteristics, evaluating their occurrence together provides a more comprehensive understanding of historical waste disposal practices, contaminant migration, and potential human exposure. Integrating environmental chemistry, contaminant fingerprinting, historical site operations, atmospheric transport, environmental sampling, toxicology, and quantitative exposure assessment strengthens source attribution while providing a scientifically rigorous basis for evaluating long-term environmental contamination. This multidisciplinary approach is fundamental to modern environmental forensic investigations involving persistent organic pollutants and historical industrial waste management sites (ASTM International, 2021; National Academies of Sciences, Engineering, and Medicine, 2013).
Methods
A multidisciplinary environmental forensic investigation was conducted to evaluate historical contaminant releases associated with a former industrial waste disposal facility and to reconstruct the environmental processes responsible for long-term human exposure. The investigation integrated historical records review, environmental chemistry, atmospheric science, engineering, hydrogeology, geographic information systems (GIS), air dispersion modeling, exposure assessment, toxicology, epidemiology, and quantitative human health risk assessment to develop a scientifically supported conceptual site model describing the complete source-to-receptor pathway. Rather than relying upon a single dataset, multiple independent lines of evidence were evaluated using a weight-of-evidence framework to characterize historical site conditions, identify contaminant transport mechanisms, and estimate potential human exposure over several decades (ASTM International, 2021; U.S. EPA, 1989).
The investigation began with a comprehensive review of historical operational records, aerial photographs, engineering documentation, regulatory files, historical environmental investigations, and available environmental monitoring data. Historical site activities were evaluated to identify potential contaminant source areas, reconstruct waste management practices, and determine how operational changes influenced contaminant migration over time. Historical aerial imagery and engineering information were particularly valuable for identifying periods of active waste handling, exposed soil conditions, changes in land cover, and post-operational site activities that may have influenced fugitive dust generation and long-term environmental transport. These historical evaluations formed the foundation for developing a comprehensive conceptual site model that integrated changing site conditions with contaminant fate and transport processes (ASTM International, 2021; U.S. EPA, 2017).
Atmospheric transport of contaminated particulate matter was evaluated using accepted air dispersion modeling techniques to estimate the migration of fugitive dust generated during historical site operations and subsequent post-operational land use. Representative emission scenarios incorporated soil disturbance associated with waste handling, heavy equipment operation, vehicle traffic, wind erosion, and other mechanisms capable of suspending contaminated soil particles into the atmosphere. Emission factors derived from established regulatory guidance were combined with meteorological information, source characteristics, terrain effects, and deposition parameters to estimate airborne particulate concentrations and long-term contaminant deposition. Geographic information systems were used to evaluate predicted deposition patterns relative to surrounding environmental receptors and to compare modeled results with historical environmental sampling data (U.S. EPA, 2017; Cowherd et al., 2006).
Environmental monitoring data from multiple media, including soil, indoor dust, groundwater, surface water, and other available environmental samples, were evaluated to characterize contaminant occurrence and migration throughout the surrounding environment. Historical analytical results were reviewed to identify concentration trends, evaluate contaminant distributions, compare observed concentrations with representative background conditions, and assess whether measured environmental data were consistent with predicted transport pathways identified through atmospheric modeling and historical site reconstruction. Statistical analyses, including upper confidence limit calculations where appropriate, were used to develop representative exposure point concentrations for quantitative risk assessment while minimizing uncertainty associated with environmental variability (U.S. EPA, 2009; U.S. EPA, 1989).
Finally, quantitative exposure assessment and human health risk assessment were performed by integrating contaminant concentrations, exposure assumptions, toxicological reference values, and established regulatory methodologies. Potential exposure pathways—including incidental ingestion of contaminated soil and dust, dermal contact, and inhalation of resuspended particulate matter—were evaluated for representative residential and recreational scenarios. Toxicity-weighted concentrations for dioxins were calculated using internationally accepted toxic equivalency methodologies, while cumulative cancer risks and non-cancer hazard indices were estimated using current U.S. Environmental Protection Agency guidance. Integrating environmental chemistry, engineering analyses, atmospheric modeling, exposure science, and toxicology provided a scientifically rigorous framework for evaluating historical environmental contamination and demonstrating the multidisciplinary capabilities required for complex environmental forensic investigations (Van den Berg et al., 2006; U.S. EPA, 1989).
Results
The environmental forensic investigation demonstrated that multiple independent lines of scientific evidence supported a conceptual model in which historical waste disposal activities resulted in the long-term migration of persistent organic contaminants through several interconnected environmental pathways. Historical site reconstruction, environmental sampling, atmospheric dispersion modeling, engineering analyses, and quantitative exposure assessment collectively indicated that contaminant transport occurred through both direct and indirect mechanisms over extended periods. Rather than relying on a single source of information, the investigation integrated environmental chemistry, contaminant fate and transport, toxicology, and engineering principles to evaluate the complete source-to-receptor pathway using a multidisciplinary weight-of-evidence approach (ASTM International, 2021; U.S. EPA, 1989).
Historical site evaluations demonstrated that contaminant migration varied substantially throughout the operational and post-operational history of the disposal facility. During active waste management, soil disturbance associated with waste placement, heavy equipment operation, grading activities, and material handling likely generated contaminated fugitive dust capable of transporting particle-bound contaminants beyond the disposal area. Following the cessation of waste disposal activities, exposed soils remained susceptible to wind erosion and repeated mechanical disturbance, creating additional opportunities for long-term contaminant redistribution. Engineering evaluations indicated that changing site conditions—including vegetation cover, surface stabilization, access restrictions, and land use—significantly influenced the magnitude and frequency of fugitive dust emissions over time (Cowherd et al., 2006; U.S. EPA, 2017).
Air dispersion modeling demonstrated that contaminated particulate matter released during representative historical activities could be transported beyond the source area under typical meteorological conditions before depositing onto nearby environmental surfaces. Predicted deposition patterns were generally consistent with the spatial distribution of contaminants identified during environmental investigations, supporting atmospheric transport as a scientifically plausible mechanism contributing to off-site contaminant migration. Integrating engineering emission estimates with atmospheric dispersion modeling provided an independent line of evidence supporting historical contaminant movement and complemented environmental sampling data collected over multiple decades (U.S. EPA, 2017; American Meteorological Society & U.S. EPA, 2019).
Evaluation of environmental sampling results further demonstrated that persistent organic contaminants occurred across multiple environmental media, including soils, indoor dust, and other depositional environments, reflecting the long-term environmental persistence of particle-associated contaminants. The investigation found that integrating historical sampling data with statistical analyses, contaminant distributions, and representative background concentrations provided a more scientifically robust interpretation than relying on individual analytical results alone. Long-term depositional media, particularly indoor dust, provided valuable information regarding cumulative historical contaminant loading because they integrate airborne particulate deposition over many years rather than representing only short-term environmental conditions (ATSDR, 1998; U.S. EPA, 2009).
Finally, quantitative exposure assessment demonstrated the importance of evaluating cumulative human exposure across multiple completed exposure pathways rather than considering individual pathways independently. Integrating historical environmental concentrations, contaminant fate and transport, exposure science, toxicological reference values, and risk assessment methodologies allowed the investigation to estimate representative long-term residential and recreational exposures under realistic environmental conditions. By combining environmental chemistry, engineering analyses, atmospheric science, toxicology, and quantitative risk assessment within a comprehensive environmental forensic framework, the investigation provided a scientifically defensible evaluation of historical contaminant migration and human exposure that supports environmental consulting, regulatory investigations, remediation planning, and expert witness services involving complex contaminated sites (National Academies of Sciences, Engineering, and Medicine, 2013; U.S. EPA, 1989).
Conclusions
This environmental forensic investigation demonstrated that evaluating historical contamination at former industrial waste disposal facilities requires a comprehensive, multidisciplinary scientific approach integrating environmental chemistry, engineering, atmospheric science, hydrogeology, exposure assessment, toxicology, quantitative risk assessment, and environmental modeling. Because persistent organic contaminants may remain in environmental media for decades after disposal activities have ceased, reconstructing historical releases requires the integration of historical operational information, environmental sampling, contaminant fate and transport, and engineering analyses to develop a scientifically supported conceptual site model. The weight-of-evidence approach employed in this investigation strengthened the evaluation of contaminant sources, migration pathways, and potential human exposure while reducing uncertainty associated with any individual dataset (ASTM International, 2021; U.S. EPA, 1989).
The investigation demonstrated that airborne transport of contaminated fugitive dust represented an important mechanism for distributing particle-bound contaminants beyond the original disposal area. Engineering evaluations, historical site reconstruction, and atmospheric dispersion modeling collectively demonstrated that waste handling activities, heavy equipment operation, exposed soils, wind erosion, and subsequent land use all contributed to varying degrees of contaminant transport throughout the site’s operational and post-operational history. Evaluating these changing site conditions over time provided a more scientifically accurate understanding of historical exposure potential than considering only present-day environmental conditions. Integrating atmospheric science with environmental chemistry and historical engineering information proved essential for reconstructing long-term contaminant migration (Cowherd et al., 2006; American Meteorological Society & U.S. EPA, 2019).
The investigation further demonstrated the importance of evaluating multiple environmental media when assessing long-term human exposure to persistent organic contaminants. Contaminants associated with airborne particulate matter may accumulate in soils, indoor dust, surface water, sediments, and other depositional environments where they remain available for human exposure long after their initial release. Combining environmental sampling, statistical analyses, toxic equivalency calculations, exposure assessment, and quantitative human health risk assessment provided a comprehensive evaluation of cumulative exposure across multiple completed pathways. This integrated methodology substantially improved confidence in the environmental forensic reconstruction while providing a scientifically defensible framework for evaluating historical contamination and potential health risks (Van den Berg et al., 2006; ATSDR, 1998).
This case study highlights the critical role of environmental forensic science in investigating historical contamination involving persistent organic pollutants and complex environmental exposure scenarios. By integrating historical site reconstruction, environmental chemistry, atmospheric dispersion modeling, engineering analyses, geographic information systems, contaminant fate and transport, toxicology, and quantitative risk assessment, RoseyFields provides scientifically rigorous evaluations capable of addressing some of the most technically challenging environmental investigations. These multidisciplinary investigations support environmental consulting, regulatory investigations, remediation planning, environmental due diligence, and expert witness services through objective, evidence-based scientific analyses that improve understanding of contaminant sources, environmental transport, historical exposures, and potential human health risks while remaining consistent with accepted environmental science and current regulatory guidance (National Academies of Sciences, Engineering, and Medicine, 2013; U.S. EPA, 1989).
This investigation was conducted under the direction of Dr. Paul Rosenfeld, an environmental scientist and environmental forensic expert with extensive experience in contaminated site investigations, historical waste disposal reconstruction, fugitive dust transport analysis, exposure assessment, and human health risk evaluation. Dr. Rosenfeld’s work focuses on complex environmental contamination matters involving dioxins, PCBs, persistent organic pollutants, contaminated soils and indoor dust, air dispersion modeling, contaminant fate and transport, multimedia exposure pathways, and long-term residential and recreational exposure scenarios affecting surrounding communities. His expertise includes reconstructing historical release mechanisms through the integration of historical site operations, environmental chemistry, atmospheric modeling, hydrogeology, geographic information systems (GIS), toxicology, quantitative exposure assessment, and regulatory risk evaluation to determine whether historical industrial waste 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 dioxin and PCB contamination, fugitive dust transport, contaminated soil and indoor dust exposure, source attribution, and long-term environmental and human health risks associated with historical industrial waste disposal operations.
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