November 7, 2022

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Geosyntec to Present on Innovation and Sustainability at SETAC

Geosyntec will deliver six presentations, co-chair a technical session, and sponsor a nontechnical session at the Society of Environmental Toxicology and Chemistry (SETAC) North America 43rd Annual Meeting in Pittsburgh, Pennsylvania on November 13 through 17, 2022.

Presenters from Geosyntec include Jason Conder, Ph.D. (California), Jean Zodrow, Ph.D., (Colorado), Rachel Zajac-Fay (Florida), Kaylin McDermett, Ph.D. (Pennsylvania), Caitlin Johnson, Ph.D. (Massachusetts), Zach Pandelides, Ph.D. (Mississippi), and Florent Risacher, (Ottawa). Other Geosyntec staff attending are Amanda McNally, P.E., James Culp, P.G., Heather Tahon, BCES, Ron Arcuri, P.G. (Pennsylvania), Christine Julias, P.E. (New Jersey), and Regina Gray, Ph.D. (Maine). They will be available at Booth #29 for questions and networking during the conference.

The SETAC North America 43rd Annual Meeting will be focused on "Bridging Innovation and Sustainability" as its theme.

SETAC is a not-for-profit, worldwide professional organization comprised of about 5,300 individuals and institutions in over 90 countries dedicated to the study, analysis and solution of environmental problems, the management and regulation of natural resources, research and development, and environmental education. Its mission is to support the development of principles and practices for protection, enhancement and management of sustainable environmental quality and ecosystem integrity.

Conference Participation

Title: Re-Thinking the Kinetics of Metals in Sediment Passive Samplers Using Reverse Tracers
Presenter: Florent Risacher, Geosyntec
Type: Platform
Session: Quantifying the Fate and Effects of Metals: Balancing Complexity with Practicality
Date/Time: Tuesday, November 15, 2022 at 10:00 a.m. EDT
Abstract: Measuring metal availability in sediment porewater can be a powerful tool for assessing the ecological risk of contaminated sediments, planning remedial actions, or measuring remedial success. Passive sampling using diffusion-based dialysis samplers ("peepers") are widely used for measuring the availability of metal in sediment porewater. Peepers function by allowing the sampled water to equilibrate with lab-provided water contained in an isolated compartment via passive diffusion through a semi-permeable membrane. After an equilibration period, the peeper is retrieved, and the peeper solution is analyzed for metals (e.g., Zinc, Mercury) and reported as a concentration in water that can be compared to a criteria or used in fate modeling.

Title: Early developmental exposure to Δ9-tetrahydrocannabinol causes persistent multigenerational hyperactivity and altered brain mitochondrial function in zebrafish
Presenter: Zach Pandelides, Geosyntec
Type: Poster
Session: 1.11 | Poster Only: Environmental Toxicology and Stress Response
Date: Tuesday, November 15, 2022
Abstract: A major constituent of cannabis, Δ9-tetrahydrocannabinol (THC), is a contaminant of emerging concern due to limited information on its environmental impact. Due to THCs known modes of action, evaluation of the potential adverse neurological effects following exposure to THC during early development is crucial. Following exposure to 0.08, 0.4, or 1 μM THC from 6-96 hours post fertilization (hpf) in wild-type (5D) zebrafish, latent behavioral effects caused by THC were assessed at 120 hpf (larval), 3 weeks post fertilization (wpf) (juvenile), 11 wpf (onset of sexual maturity) and 24 wpf (adult). Using the larval photomotor response test (LPR), hyperactivity in the dark phase was evident in fish exposed to 0.4 μM THC. Open field tests (OFT) conducted at 3 and 11 wpf indicated dose-dependent hyperactivity and increased thigmotaxis at the two highest THC concentrations. Effects on thigmotaxis did not persist into adulthood. Yet, adult zebrafish behavior in the OFT revealed significant hyperactivity (increased velocity) amongst both sexes of fish exposed to 0.4 or 1 μM THC. Furthermore, hyperactivity in the 120 hpf LPR test persisted into the F1 generation, offspring of the developmentally exposed fish at all concentrations tested. Developmental exposure to THC also caused significant changes to the size of the F0 fish by 24 wpf, with significantly lower and higher weights in fish exposed to the lower and higher THC concentrations, respectively. Developmental exposure to THC also caused persistent alterations in brain mitochondrial function such as increased basal oxygen consumption rate and reserve capacity. The role of cannabinoid receptor 1 (CB1) in mediating THCs effects on behavior was also measured using cnr1-/- zebrafish, which suggested that the anxiety-like behavior was mediated by CB1 but hyperactivity was not. Collectively, these results showed that exposure to THC during a critical period of development caused behavioral and mitochondrial alterations that persisted into adulthood and the F1 generation. This work was supported by the National Institute on Drug Abuse R21DA044473-01.

Title: Sensationalized News and Emerging Contaminants: A Cautionary Tale from PFAS applied to Microplastics
Presenter: Rachel Zajac-Fay, Geosyntec
Type: Platform
Session: Risk Communication: Strategies for Cross Communication among different Science Disciplines with Risk Issues
Date/Time: Wednesday, November 16, 2022 at 10:00 a.m. EDT
Abstract: Risk communication is an essential aspect of risk assessment and toxicology yet it can be an overlooked tool. We live in the Digital Age where information is quickly and widely disseminated through all forms of media. With this abundance of information, scientists and science communicators specializing in emerging contaminants face a unique challenge in interpreting and communicating their findings. Published literature can easily be misconstrued and sensationalized for a news headline, which can cause unnecessary alarm from the public, create mistrust between the public and scientists, and cause confusion regarding actual toxicological information. We have seen this with PFAS, and we are seeing it with microplastics. Microplastics are one of the latest emerging contaminants that has come into the public eye; the quantity of peer reviewed literature has exploded in the past few years. With this new hot topic comes headlines such as, "You're eating a credit card worth of plastic each week." This presentation will explore the issues of sensationalizing toxicity of emerging contaminants, provide a case study using PFAS and lessons learned, discuss relevant microplastic headlines, and provide tools and best practices that scientists and science communicators can use when communicating emerging contaminants.

Title: Assessing potential perfluoroalkyl substances (PFAS) trophic transfer to crickets (Acheta Domesticus)
Presenter: Kaylin McDermett, Geosyntec
Type: Platform
Session: PFAS and related compounds in terrestrial and aquatic wildlife: exposure, uptake, tissue distribution, and toxic effects
Date/Time: Wednesday, November 16, 2022 at 2:00 p.m. EDT
Abstract: Although many studies have assessed the bioaccumulation of perfluoroalkyl substances (PFAS) in plant tissues, to date, there has been minimal research on the bioaccumulation of PFAS in soil invertebrates that results from consuming PFAS-contaminated media. This study focused on two different consumption pathways in a population of crickets: individuals consuming PFAS-contaminated alfalfa (Medicago sativa), and individuals consuming PFAS-spiked drinking water. Alfalfa was grown in a greenhouse and irrigated with PFAS-spiked water (~1 ppm) containing seven unique PFAS. The alfalfa was then harvested and fed to crickets. Another population of crickets was supplied with PFAS-spiked drinking water at similar concentrations for direct consumption. Alfalfa tissue accumulation of PFAS and subsequent consumption by the crickets resulted in overall similar cricket tissue concentrations to the crickets who consumed PFAS-spiked water directly. This indicates that source concentration (water) may play a key role in assessing bioaccumulation of PFAS up the food chain. Additional critical information about PFAS chain-length on bioaccumulation to the crickets was also explored, and bioconcentration factors (BCFs) for the seven PFAS of interest were calculated. To our knowledge, this is the first study which has assessed not only the direct potential of PFAS trophic transfer from contaminated vegetation, but also highlights the similarities in bioaccumulation, regardless of ingestion pathway or plant accumulation. As PFAS bioaccumulation and biomagnification in food webs are topics that remain in question, this work aimed to provide more understanding of how PFAS enters the food web through soil invertebrates.

Title: Polycyclic Aromatic Hydrocarbon Concentrations in Plasma Samples are Associated with Cardiovascular Risk Biomarkers in a Near-Roadway Study Human Population
Presenter: Caitlin Johnson, Geosyntec
Type: Poster
Session: 4.20 Poster Only: Chemistry and Exposure Assessment
Date: Wednesday, November 16, 2022
Abstract: Polycyclic aromatic hydrocarbons (PAHs) are air pollutants associated with multiple adverse health effects in humans. PAHs exposure in humans is typically determined by measuring hydroxylated PAH metabolites in urine, but little is known about plasma concentrations of un-metabolized PAHs. The goal of this study was to quantify 15 PAHs in the plasma from a near-highway study population and assess relationships between plasma PAH concentrations and cardiovascular risk biomarkers. Plasma samples from 58 non-smokers were analyzed using high-resolution gas chromatography mass spectrometry. Anthracene, phenanthrene, fluoranthene, pyrene, and benzo[ghi]perylene were detected in > 70% of plasma samples and their joint relationship with each of four cardiovascular risk biomarkers (interleukin-6 (IL-6), c-reactive protein (hsCRP), tumor necrosis factor receptor II (TNF RII), and fibrinogen) was investigated using weighted quantile sum regression and Bayesian kernel machine regression. Models of IL-6 indicated positive (p < 0.001) nonlinear relationships with benzo[ghi]perylene, fluoranthene, and pyrene. For hsCRP, positive nonlinear associations (p < 0.05) were found with anthracene, phenanthrene, and benzo[ghi]perylene; however, fibrinogen and TNF RII were not significantly (p > 0.05) associated with any plasma PAH concentrations. Results of this study suggest PAH levels in human plasma are associated with biomarkers of cardiovascular risk and support further evaluation of relationships between PAHs in plasma and adverse health effects.

Title: Validation of Food Web Models for PFAS
Presenter: Jean Zodrow, Geosyntec
Type: Platform
Session: PFAS and related compounds in terrestrial and aquatic wildlife: exposure, uptake, tissue distribution, and toxic effects
Date/Time: Thursday, November 17, 2022 at 2:00 p.m. EDT
Abstract: Food web models allow ecological risk assessors to use concentrations of per- and polyfluoroalkyl substances (PFAS) in abiotic media (soil, sediment, water) to predict concentrations of PFAS in wildlife diet items, enabling estimation of site-specific dietary doses for wildlife, a critical part of ecological risk assessments (ERAs) at PFAS-impacted sites. While food web models provide a useful tool for ERA, there are concerns that food web models for PFAS have not met the level of validation obtained by food web models routinely used for ERAs of other chemicals (e.g., polychlorinated biphenyls, metals, pesticides). This concern can lead to a lack of confidence around food web modeling for PFAS which prevents utilizing food web models at PFAS-impacted sites. Abiotic media concentrations and other data important for food web modeling have emerged at many PFAS sites in the last few years since food web models for PFAS were first developed, allowing a robust validation of these models. Data from these field studies, including abiotic media such as surface water and sediment at aquatic sites and soil at terrestrial sites, can be used to generate predictions of PFAS in tissue (using food web models) that can be compared to the measurements of PFAS in biota (invertebrates, fish, plants). In this way, the food web model accuracy can be assessed, providing an important validation of the models for use in site-specific ERAs. In this study, several aquatic and terrestrial PFAS-impacted sites with high quality data were selected for validation. Model-predicted concentrations of PFAS (primarily perfluoroalkyl carboxylates and sulfonates) in biota (i.e., invertebrates, plants, and fish) were generally within a factor of 5 of the measured values. Importantly, the model predictions generally agreed with measurements in terms of identifying the biota with the highest concentrations of PFAS at the sites. This validation effort provides confidence in PFAS food web modeling and helps identify areas of continued uncertainty and refinement of modeling efforts.

Title: Can we Apply a Site-Specific Ecological Risk Assessment Framework for Microplastics?
Presenter: Rachel Zajac-Fay, Geosyntec
Type: Platform
Session: Microplastics in the Environment and Risk Assessment: A One-Health Perspective
Date/Time: Thursday, November 17, 2022 at 2:40 p.m. EDT
Abstracts: Microplastic toxicity literature for ecological receptors are being published every month. Microplastic state of science is quickly evolving and may lead to the development of regulations, at which point the potential ecological risks posed by microplastics will need to be evaluated in a manner like other regulated chemicals. Although laboratory studies have shown that exposure to microplastics can cause toxic effects in some organisms, these effects still need to be applied to site-specific exposure scenarios to assess risk to ecological receptors at a particular site. Although multiple papers in the past year have proposed microplastic risk assessment frameworks to capture their diverse properties and assess multiple exposure sources for receptors, many data gaps still exist that prevent site-specific ecological risk assessments from being completed.
Fundamental data gaps, such as sampling and analysis, quality control, and data reporting, also still exist that contribute to uncertainty in assessing microplastics. Can the proposed frameworks be applied to a site-specific approach, or can a new framework be developed following the EPA's 8-step ecological risk assessment framework for CERCLA sites? Using the EPA CERCLA paradigm, this presentation will consider how an ecological risk assessment for microplastics can be applied to individual sites by walking through the EPA process. This includes problem formulation (such as selecting appropriate endpoints used in risk decision making); exposure and effects assessments (such as developing direct toxicity values, uptake factors, and wildlife toxicity reference values); and risk characterization (calculating hazard quotients). As microplastics are widespread in the environment, another uncertainty to address is how to factor in an assessment of background concentrations that are unrelated to the site. This presentation will discuss the importance of resolving data gaps so that site-specific ecological risk assessments can be performed and decisions regarding investigations and potential remediation can be made for individual sites.

Title: Considerations for the Use of Zebrafish Toxicity Data for PFOS Aquatic Life Criteria Derivation
Presenter: Jason Conder, Geosyntec
Type: Poster
Session: PFAS and related compounds in terrestrial and aquatic wildlife: exposure, uptake, tissue distribution, and toxic effects
Date/: Thursday, November 17, 2022
Abstract: Zebrafish (Danio rerio) is among the most sensitive aquatic species to perfluorooctane sulfonate
(PFOS). Effect benchmarks from laboratory zebrafish PFOS toxicity studies in PFOS-spiked water strongly influence PFOS aquatic life criteria calculated by environmental regulatory agencies and other
researchers. This presentation will present a review of PFOS effects benchmarks for lethality, growth, and reproduction endpoints from more than 20 zebrafish toxicity studies, including a recent multi-generational study (currently in peer review) conducted by the US Army Corps of Engineers Engineer Research & Development Center (ERDC) and the Sediment Management Work Group, in collaboration with the US Environmental Protection Agency (USEPA). Review results from most acute studies (approximately 7 days or less) indicate LOEC (lethality, malformations) and EC50 values for PFOS are generally greater than 1,000 µg/L. Twelve key studies examining longer exposures (including multigenerational exposures of 300 days or more) indicate chronic thresholds that are one order of magnitude lower. For example, the multi-generational ERDC study found that 100 µg/L resulted in highly variable impacts on mortality, ranging from 0% to 40% among the three generations evaluated (no significant effects on growth or reproduction were observed). This result was consistent with 10 of the other 11 chronic zebrafish studies, which indicated LOEC values (various endpoints) in the 40 to 400 µg/L range. The study that noted an exception to this general observation (Keiter et al., 2012) found a 5-10% reduction in growth at exposures as low as 0.6 µg/L. This study was excluded from calculations conducted for USEPA's April 2022 draft ambient water quality chronic criterion for PFOS in freshwater, primarily because it was limited in scope (only 3 PFOS dose levels and only 2 replicates per dose) and limited in measurement of PFOS in exposure water. Given the limitations of the Keiter et al. (2012) study and the 2- to 3-order of magnitude difference between its 0.6-µg/L threshold value and values from the other chronic studies, the Keiter et al. (2012) study should not be quantitatively included in criteria calculation or site-specific decisions to protect fish. Overall, the weight of evidence indicates that that the thresholds for ecologically relevant chronic effects of PFOS in fish are in the 40 to 400 µg/L range.

Technical Session Title: Risk Communication: Strategies for Cross Communication among difference Science Disciplines with Risk Issues
Co-Chair: Rachel Zajac-Fay, Geosyntec
Session: Session 7.06
Date/Time: Wednesday, November 16, 2022 from 10 a.m. to 12:40 p.m. EDT

Non-Technical Session: Geosyntec is sponsoring the "Gender and Equity Allyship in the Workplace: A Conversation with Aurora Sharrard"
Date/Time: Tuesday, November 15, 2022 from 5:30 to 7:30 p.m. EDT

More Information

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