Society of Environmental Toxicology and Chemistry

We are thrilled to announce that our upcoming spring meeting has garnered an exceptional response from professions and students across the region. The accepted abstracts cover a wide range of environmental and toxicological research topics. We look forward to exploring the insights and advancements they bring to the environmental science community.

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PLATFORM ABSTRACTS

Field Demonstrations of In-Situ Sequestration and Degradation of PCBs in Sediments with Bioamended Activated Carbon

Kevin R Sowers and Upal Ghosh 

Abstract: While PCB biodegradation was first observed in the field nearly four decades ago, engineering for field-scale remedies has been elusive.  In this work, anaerobic organohalide respiring bacteria and aerobic PCB oxidizing bacteria were grown in production-scale bioreactors and applied to sediments using a pelleted AC agglomerate (SediMite™) as a delivery system. The innovative aspect of the technology is the application of large numbers of PCB-transforming microorganisms to circumvent the threshold PCB concentration for growth. The bioamended AC serves not only as a solid substrate for the delivery of the microorganisms but also adsorbs and concentrates hydrophobic PCBs in close proximity to the biofilm of PCB-transforming bacteria. We conducted field applications of bioamended AC at several sites in the US, including a Superfund site. Methods were successfully developed for production-level inoculation systems to deploy active PCB-transforming microorganisms for full-scale treatment of PCB impacted sediments.  Pilot-scale studies have shown reductions of total PCBs in the field demonstrating a 72% reduction of total PCBs 15 months after treatment in an industrial cooling pond, and 77% reduction of total PCBs 4.3 years after treatment in a wastewater treatment pond.  An ongoing project is demonstrating the technology at the New Bedford Harbor Superfund site.  These field studies show the effectiveness and engineering scalability of bioremediation as an in situ strategy to help address the widespread need to reduce contamination of the aquatic food web from exposure to sediment-bound PCBs.  

Acknowledgements: This work was supported by the National Institutes of Environmental Health Sciences, Small Business Innovation Research (R43ES032365 and R44ES032365), and U.S. Department of Defense, Environmental Security Technology Certification Program (ER-201215). The authors declare the following competing financial interest(s): Several authors are co-inventors of patents related to the technology described in this paper for which they are entitled to receive royalties. K.R.S. is a co-inventor of U.S. Patent Nos. 6,946,248 and 7,462,480 B2 issued to the University of Maryland Baltimore County (UMBC) and Medical University of So. Carolina. K.R.S. and U.G. are co-inventors of U.S. Patent No. 8,945,906 issued to UMBC. U.G. is a co-inventor of US Patent No. 7,101,115 B2 issued to Stanford University and U.S. Patent No. 7,824,129 issued to UMBC. In addition, U.G. and K.R.S. are partners in a startup company (RemBac Environmental) that has licensed the three former technologies; U.G. is a partner in a startup company (Sediment Solutions) that has licensed the latter technology.

Adaptive Management under the Upper Hudson River Habitat Operation, Maintenance, and Monitoring Program

Authors: WSP (Chelsea Krieg, Juliana Atmadja, Kenneth Takagi, Mike Traynor, Chris Bradley), USACE – Kansas City District (Kathy Baker), EPA Region II (Gary Klawinski, Mike Cheplowitz)

The Hudson River Superfund Site remains one of the largest remedial efforts in the country. The project was of the first projects of its kind and many aspects of the remedial design, from dredging techniques and cap installation to habitat reconstruction and monitoring, had not been attempted at its scale. This necessitated the developing large-scale implementation practices, monitoring assessment, and a unique success criteria evaluation.

The Hudson River Superfund Site extends from Hudson Falls, NY to the Battery in New York City, encompassing a 200-mile stretch of the Hudson River. The Site is divided into multiple Operable Units (OUs). This discussion focuses on OU2, the 40 miles of the Upper Hudson River (UHR) between Fort Edward, NY and the Federal Dam in Troy, NY. This project is currently in Operation, Maintenance, and Monitoring (OM&M). The OU2 remedy included dredging and capping (2009 and 2011 to 2015), and habitat reconstruction (2010 to 2016), resulting in the establishment of over 120 acres of riverine fringing wetland and submerged aquatic vegetation habitat.

Between the Record of Decision (ROD; 2002) and preparation of the OM&M plan (2011) habitat assessment involved extensive data collection and interagency collaboration to support development of habitat assessment methods, statistical analyses, and derive success criteria. Project documents anticipated implementing the reconstruction in an adaptive management framework. Since initial development of the UHR Habitat Monitoring, Maintenance, and Adaptive Management (MM&AM) program, new large-scale, high-resolution, survey technologies and data collection techniques have emerged. Throughout this process, adaptive management has afforded the project the flexibility to adjust field assessment methods, determine assessment-scale, and success evaluation approach which has been critical for a comprehensive and effective habitat management program. This presentation discusses how the UHR MM&AM program and future work have been shaped by the lessons learned over the 23 years since the ROD, 14 years since the development of the work plan, and 13 years since initial reconstruction.

 

Effects of pH and dissolved organic matter on PFAS accumulation at air–water interfaces in groundwater

Authors: Ewuola Akinola Ayoola, PhD. and Erica R. McKenzie, PhD.

Per- and polyfluoroalkyl substances (PFAS) can be persistent groundwater contaminants whose subsurface transport is strongly influenced by accumulation at interfaces. Due to their surfactant like properties, PFAS accumulate at air–water interfaces, which affects vadose zone migration.  However, quantitative experimental data linking pH and dissolved organic matter to interfacial enrichment are limited. In this study, we employed a glass slide dipping approach in synthetic groundwater to directly investigate the combined effects of pH and dissolved organic matter (DOM) on PFAS enrichment at the air–water interface. For a given perfluorinated chain length, sulfonates accumulated most strongly at the interface, followed by fluorotelomer sulfonates, then carboxylates; hexafluoropropylene oxide dimer acid showing the least enrichment. Interfacial enrichment increased systematically with perfluoroalkyl chain length due to increased hydrophobicity. PFAS enrichment varied systematically with DOM concentration. Compared to a DOM-free system, at low DOM concentrations (0.5–25 mg L⁻¹), enrichment was enhanced, while higher DOM levels suppressed air–water interfacial accumulation, particularly for short-chain compounds. Under low-DOM conditions (5 mgL⁻¹), long-chain sulfonates demonstrated pronounced enrichment, with PFDS reaching enrichment factors up to 67.1. PFAS surface enrichment declined with increasing pH, implicating electrostatic repulsion and competitive displacement by natural organic matter as key mechanisms governing enrichment. Universally, the ether compound HFPO-DA showed minimal air–water interfacial accumulation. Statistical analysis (two-way ANOVA, p < 0.05) confirmed significant independent and interactive effects of pH and DOM on PFAS surface enrichment. These findings demonstrate the influence of groundwater chemistry on PFAS enrichment in unsaturated systems.

 

Tracking PCB Sources with passive sampling: A Seasonal Assessment of pollutant dynamics in the Tidal Christina River

Azmat Naseem(anaseem1@umbc.edu), Upal Ghosh (ughosh@umbc.edu), Nathalie Lombard (nlombard@umbc.edu)(UMBC, Baltimore, MD, USA). Kim Brinson (KBrinson@brightfieldsinc.com, Brightfields Inc.), John Cargill (John.Cargill@delaware.gov, DNREC)

Background/Objective:
The Christina River, a tidally influenced urban tributary in northern Delaware, represents a critical, yet under-characterized urban waterway that typifies the challenges of historical contamination repositories in tidal systems. Elevated levels of polychlorinated biphenyls (PCBs), dieldrin, and chlordane have led to Clean Water Act regulations and necessitated fish consumption advisories. However, existing PCB data remain fragmented, limiting contamination assessments and management decisions. This study aims to address data gaps in pollutant dynamics, bioaccumulation, and seasonal variability using passive samplers to refine the site conceptual model, define key sources, and guide remediation strategies.

Approach/Activities:
Polyethylene (PE) passive samplers preloaded with performance reference compounds (PRCs) were deployed at 48 locations in the Christina River and Brandywine Creek along both sides of the river to measure freely dissolved PCBs in surface water and sediment porewater during Spring and Summer 2024, Spring 2025. PRC-corrected results were used to quantify equilibrium concentrations and assess hydrodynamic influences. Paired comparisons, ANOVA, and correlation analyses were used to evaluate differences across river reaches and relationships among contaminant classes. Ongoing work involves developing a mass-balance load framework to quantify the relative importance of tributary, sediment, and atmospheric pathways, expressed as annualized loads.

Results/Lessons Learned:
The thermodynamic profile across the Christina River reveals a consistent 'Source-to-Sink' transition. Reach E functions as a multi-contaminant source where petrogenic PAHs and legacy PCBs bypass the sediment's carbon-carrying capacity, while Reach F effectively sequesters both industrial and agricultural legacy loads, acting as a regional environmental buffer. Critically, sites exhibiting critical source behavior in one season maintained that designation in subsequent seasons, validating that high-priority sites identified through passive sampling represent persistent contamination rather than transient concentration spikes.

 

Managing Environmental Data on Contaminated Sites: Approaches, Tools, and Lessons Learned

Colin Mills, HDR (Professional)

Environmental Data is what we base our decisions on. It’s at the core of our businesses, applications, and technical practices. Good data management practices start before the first pump is lowered down a well or the first sampling device breaks ground. Environmental Data Management (EDM) is a complex topic that requires a depth of knowledge and skills from multiple backgrounds, but it doesn’t have to be overly difficult or utilize expensive software to manage and utilize. This presentation will demonstrate approaches and tools used to set up environmental projects and present some specific examples of how prior planning can prevent poor performance or undesired outcomes later. It will also cover ways to scale your data management and analysis to the job at hand. Large and complex sampling programs benefit from a well-established data management program but what about that one-off job with only a handful of samples? This presentation will include some nifty tricks using common software along with more advanced techniques to process, manage and analyze data using complimentary tools and methods.

 

1,4-dioxane groundwater ex-situ process: from pilot testing through operation

Andrew Wadden, HDR (Professional)

This presentation follows the development and implementation of an ex-situ treatment process for 1,4‑dioxane within the groundwater extraction and treatment system (GWET) of a former landfill Superfund site, highlighting the progression from early pilot testing through full-scale remedial design, construction, and system operation. The Remedial Investigation identified 1,4‑dioxane impacts to groundwater in the overburden and bedrock aquifers that the pre-existing GWET system was unable to treat, as 1,4-dioxane is recalcitrant with physical properties that make conventional groundwater treatment technologies ineffective.  To address these limitations, pilot studies were conducted to evaluate the performance, reliability, and operational feasibility of multiple technologies, including advanced oxidation process (AOPs), co-metabolic bioaugmentation, and adsorption.  The results of the pilot studies served as the basis for the remedial design.  Construction of the system was recently completed and is currently in operation.  This presentation will follow the lifecycle of the 1,4-dioxane treatment process discussing each phase and the lessons learned.

 

Unpacking the Rt 31 Sludge Disposal Site: PFAS monitoring in fish from the Musconetcong River

Daniel R. Millemann¹, Brian Henning²

¹NJDEP Division of Science & Research

² NJDEP Bureau of Freshwater and Biological Monitoring

Per- and polyfluoroalkyl substances (PFAS) are a class of contaminants that have become increasingly studied due to their widespread occurrence and concerns with human health effects. Historical textile mills and manufacturing facilities have been linked to concerning levels of PFAS contamination as a result of direct discharge to surface waters or disposal of waste sludge applied to agricultural lands as fertilizer. The Rt. 31 Sludge Disposal Site in Washington Towsnship, New Jersey, has been identified as a priority site for investigation due to extensive soil and groundwater contamination above current health thresholds. Two small spring fed tributaries of the Musconetcong River originate within the area of concern and have elevated concentrations of PFAS in their surface water The Musconetcong River is a National Wild and Scenic River and receives nearly 10% of New Jersey’s total annual allotment of hatchery reared rainbow trout. Edible muscle tissue from American eel, redbreast sunfish, and rainbow trout collected during 3 sampling events from 3 different sites along the Musconetcong River were tested for PFAS to determine potential impacts to natural resources and provide a basis for the development of fish consumption advisories, if needed. Average fillet PFOS concentrations for rainbow trout captured in the Musconetcong River ranged between 1.1 and 4.9 µg/kg by site, with a sub-sample of fish collected directly from the hatchery having the lowest average concentration (0.27 µg/kg). Average concentrations in resident fish ranged from 9.6 – 18 µg/kg at the reference location, depending on species. From the two locations associated with impacted tributaries, average concentrations in resident fish ranged from 17-29 µg/kg. The highest average fillet concentrations found were from an opportunistic sample of American eels (79 µg/kg) and brown trout (51 µg/kg) directly from an impacted tributary. Results are also presented on additional testing of opportunistically captured fish specimens as well as mercury (Hg) and polychlorinated biphenyls (PCBs) results for relevant species.