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Case Study 13: PFAS Fate and Transport Modeling

Comprehensive PFAS Fate and Transport Modeling, Air Dispersion Analysis, and Human Health Risk Assessment for a Fluorochemical Manufacturing Facility

RoseyFields conducted a comprehensive environmental impact and human health risk assessment to evaluate legacy and ongoing contaminant releases from a large-scale fluorochemical manufacturing complex. We evaluated the environmental persistence, mobility, and toxicity of a complex suite of per- and polyfluoroalkyl substances (PFAS), specifically focusing on highly persistent long-chain PFAS, their ammonium salts, short-chain replacement chemicals, and proprietary manufacturing byproducts. The core objective of our investigation was to characterize the extent of historical contamination across multiple environmental media resulting from decades of complex industrial operations, unmonitored waste streams, and historical emission control deficiencies.

To accurately assess contaminant migration and trace residential exposure pathways, our team performed extensive environmental modeling and fate and transport analyses. We utilized advanced, regulatory-approved air dispersion modeling to reconstruct historical atmospheric stack emissions, evaluating the aerial transport and subsequent deposition of contaminants onto surrounding communities. In parallel, we conducted surface water mass-balance reconstructions to estimate historical contaminant loading and concentrations in major downstream waterways used for public drinking water supplies. This rigorous multi-pathway approach allowed us to quantify the complex atmospheric and hydrologic mechanisms driving long-range, off-site contaminant migration directly to residential receptors.

Building upon our environmental modeling, RoseyFields conducted a targeted human health risk assessment to evaluate the specific exposures experienced by the surrounding community. We successfully identified and characterized the affected residential populations by spatially and temporally correlating our air dispersion isopleths and modeled surface water concentrations with specific residential histories and public water system distribution areas. By synthesizing reconstructed historical concentrations with recent public water system monitoring data, we quantified cumulative human exposures through both the inhalation of impacted ambient air and the ingestion of contaminated drinking water. This analytical framework provided a scientifically grounded evaluation of both carcinogenic and non-carcinogenic residential risks, demonstrating our ability to seamlessly integrate complex environmental forensics with precise human exposure modeling.

This investigation was conducted under the direction of Dr. Paul Rosenfeld, an environmental scientist and environmental forensic expert with extensive experience in environmental exposure assessment, toxicology, air quality, environmental fate and transport, risk assessment, and environmental forensics. Through RoseyFields LLC, Dr. Rosenfeld provides scientific consulting, environmental forensic analysis, regulatory support, and expert witness services involving environmental contamination, human exposure, and public health. His technical oversight helped ensure that the methodologies, scientific interpretations, and conclusions presented in this case study are consistent with accepted scientific principles and current best practices.