WATERBORNE EVENTS

Society of Environmental Toxicology and Chemistry (SETAC)

SETAC North America 45th Annual Meeting

October 20th-24th, Fort Worth, Texas

Join Waterborne Environmental at the upcoming SETAC conference on October 20th-24th in Fort Worth, Texas! Our Waterborne experts will deliver oral presentations and present posters (abstracts below), and meet with colleagues within the industry. If you'd like to set up a meeting, please contact Waterborne's SETAC lead, Nathan Snyder, at snydern@waterborne-env.com.

Posters
Oral Presentations
Upcoming Events
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Waterborne Short Course

Posters

October 22 (Tuesday)  Exhibit Hall – Fort Worth Convention Center

1.20.P-Tu-078 - Assessing Surrogacy Options in Lepidoptera via Trait-Based Analyses

Paul Glaum1, Eric Peterson2, Maura Roberts1, Nathan Snyder1, Sarah Terrell1 and Maxime Vaugeois3, (1)Waterborne Environmental, Inc., (2)Syngenta Crop Protection, United Kingdom, (3)Syngenta Crop Protection, LLC

Abstract

Under the Endangered Species Act (ESA), an Ecological risk assessment (ERA) must be conducted for species designated as listed (threatened and endangered) for the registration of a chemical compound. However, laboratory experiments required to describe organismal response to chemical exposure are not possible with listed species, thereby limiting the development of critical ecotoxicological data. Surrogate species can be used in lieu of listed species in laboratory work, but this raises the important question of how to best choose surrogate species. Our project aims to develop methodologies to identify potential surrogacy options for listed Lepidopteran species based on large, multi-faceted trait datasets. To that end, we collated multiple global, continental, and national published datasets covering physiological, life-history, geographic, ecological, and evolutionary information for thousands of Lepidopteran species and integrated them into a centralized accessible database. With aid from representatives from USFWS, USGS, and academia, we identified the most descriptive and immediately operational trait variables to serve as inputs in multiple unsupervised learning algorithms aimed at clustering species based on our collated trait dataset. Results presented here detail how potential surrogate options are chosen and the unique benefits offered by different clustering algorithms, such as higher interpretability in k-means clustering vs increased flexibility of hierarchical clustering. Overall, our results indicate that comprehensive trait data across species can facilitate the search and development of surrogacy options.

Waterborne Presentations

Monday, November 14th, 10AM - 12:40PM, Session 5.06.T-06; Convention Center – Ballroom A 

Title:  Incorporating Climate Changes Scenarios to Understand Future Water Stress and Modeling its Impact on Consumer Product Chemical Exposure to the Environment. Authors: Raghu Vamshi, Waterborne Environmental, Inc., Brenna Kent, Waterborne Environmental, Inc., Scott Dyer, Waterborne Environmental, Inc. and LeTourneau University, Andrea Carrao, Kao USA, Inc.

Abstract:  Increased demand from a growing human population coupled with expansive evidence of climate change have intensified stresses on water availability and supply. The number of regions experiencing water stress is increasing, and municipalities are grappling with this stress by investing in water conservation, reuse, and recycling technologies. These methods will enable freshwater to be used in water stressed areas, however – they may require innovations in consumer products that are dependent on water for their function and disposal. Water stress in the U.S. was examined by evaluating datasets considering historic, current, and future water availability and use scenarios. Inclusion of anticipated climate change events required datasets that incorporated scenarios of estimated future population and per capita water use with high spatial resolution for the U.S. These datasets captured predicted temporal trends for the years 2020-2050 and were integrated with EPA’s Clean Water Needs Survey data, which represents municipal wastewater treatment plant infrastructure across the U.S. The consolidated information was used to develop current and future water use scenarios. The influence of future water use scenarios on down-the-drain chemical exposures were predicted by evaluating four consumer product chemicals with various phys/chem properties. Results from the modeling provided a quantitative forecast of the potential impacts of water stress on down-the-drain chemical exposure and potential risk. Incorporating spatial and temporal variation in water stress and its impact to the risk of chemicals in the environment, through the lens of future scenarios, provides a new dimension in the development of consumer products. Incorporating these issues into product development, now, will ensure that both consumers and the environment will be appropriately stewarded, especially considering future environmental challenges.

October 22 (Tuesday)  Exhibit Hall – Fort Worth Convention Center

5.14.P-Tu-176 - Development of a Mechanistic Fish Population Model to Assess Indirect Effects of Environmental Chemical Exposure

Paul Glaum1, Chiara Accolla1, Alan Samel2, Nathan Snyder1 and Paul Whatling3, (1)Waterborne Environmental, Inc., (2)Global Regulatory Sciences, FMC Corporation, (3)FMC Corporation

Abstract

The development and implementation of mechanistic ecological population models are an increasingly important component in efforts to understand and manage risk, especially with endangered species. Mechanistic population models can integrate the most current relevant data at the organismal level to forecast population dynamics under a wide variety of exposure conditions and realistic scenarios. This provides a particularly unique utility when considering indirect effects of environmental exposure at population levels far outside the ‘in vivo’ scope of laboratory experiments. An important example of this involves indirect effects on listed species via trophic links to directly affected prey organisms. The modeling platform developed here can provide forecasts of the population-level consequences on different benthic and pelagic freshwater fish species experiencing exposure-based dietary limitations. The capabilities of the model are demonstrated by presenting a modeling study of the indirect effects of an applied chemical on populations of small freshwater fish species via induced reductions of the insects in their diets. The model is a matrix model, structured for flexible integration of empirical data to inform, among other traits, biologically realistic bounds on species life history, dietary options, weight/fecundity relationships, and exposure scenarios. This assessment shows how differences in these traits manifest into different outlooks for indirect population exposure to a range of concentrations and the types of actionable inference that can follow.

October 24 (Thursday)  Exhibit Hall – Fort Worth Convention Center

5.15.P-Th-073 - What Can Twenty Years of Headwater Stream Monitoring Tell Us About Chemical Presence in the Environment and the Effects on Watershed Conditions

Jennifer Trask1, Zechariah Stone2, Sarah Terrell2, Natalie Walk3, Nathan Snyder2, Sarah E Crawford4, Richard Brain5 and Mark White6, (1)Waterborne Environmental Inc., Leesburg, United States, (2)Waterborne Environmental, Inc., (3)Field Programs - Environmental Assessment, Waterborne Environmental, Inc., (4)Syngenta, Canada, (5)Syngenta Crop Protection LLC, (6)Syngenta Crop Protection, LLC

Abstract

The United States (US) Environmental Protection Agency (EPA) required monitoring of a finite number of lotic headwater streams within watersheds highly susceptible to runoff as part of the 2003 reregistration review of atrazine. The purpose of the program was to monitor concentrations during seasonal runoff patterns relative to a conservative aquatic level of concern (LOC) defined by the sensitivity of aquatic plant communities to atrazine exposure. Designing a study to capture concentrations at both low and high stream flow, including peak periods, and combining this with a collection of key environmental data was necessary to enable a thorough and comprehensive understanding of the mechanics and patterns of atrazine transport.

Today, the Atrazine Ecological Monitoring Program (AEMP) continues after two decades of watershed monitoring. The study collects daily (or near daily) atrazine concentrations alongside high resolution environmental data at stream headwaters within watersheds classified among the upper 20th centile of vulnerability according to the USGS Watershed Regressions For Pesticides Model (WARP). While the program has been conducted in several phases, in total, monitoring has occurred at 77 sites across 13 states for a minimum of two years. Sampling locations were identified on 1st to 3rd order streams at the outlets of watersheds and were equipped with an integrated real-time data delivery system of weather stations, automatic samplers, stream stage measurement stations, and water quality sondes. Early program designs required four-day grab samples coupled with event-based sample collection. As the program matured, the expansion to daily composite sampling was supported through multiple Science Advisory Panels and the desire to support regulatory water model calibration to further refine, characterize, and contextualize potential ecological risks. Many sites have been waived from monitoring over the years for various reasons by EPA and as a result nine sites remain in the program. The presentation will discuss experiences, learnings, and recommendations.

Waterborne Short Course

Oral Presentations

October 22 (Tuesday) at 11:40 am Room 203 A - Fort Worth Convention Center

5.14.A.T-06 - An Agent-Based Model of Fathead Minnow for Lower and Higher Tiers of Ecological Risk Assessment

Chiara Accolla1, Paul Glaum1, Nika Galic2 and Maxime Vaugeois3, (1)Waterborne Environmental, Inc., (2)Syngenta AG, Switzerland, (3)Syngenta Crop Protection, LLC

Abstract

Mechanistic effect models are valuable and relevant tools that can help overcome some major challenges in ecological risk assessment (ERA), such as extrapolation across scales of biological organization, chemicals, and species challenges. In particular, models can extrapolate data generated from standard test species and consider those characteristics, like life-history traits, that could influence the susceptibility of the exposed populations of listed species.

In this study, we built on the existing literature and developed an agent-based model (ABM) for fathead minnow (FHM) to be used as a standard model for diverse ERA purposes. FHM is the most widely used small fish for different regulatory applications in ecotoxicology in North America. Consequenty, data on its life cycle and ecotoxicological laboratory experiments are available. The model is based on Dynamic Energy Budget theory, and lethal and sublethal effects have been implemented through toxicokinetic-toxicodynamic models and by altering different metabolic pathways through physiological modes of action. To ensure transparency, we followed the model-development guidance Pop-GUIDE (Population modeling Guidance, Use, Interpretation, and Development for ecological risk assessment), an approach applicable across regulatory statutes and assessment objectives that greatly facilitates the standardization of modeling development and use in ERA. The model has been developed to integrate different life-history traits, exposure scenarios and routes, as well as environmental variables of interest. Therefore, it can be easily adapted to represent different fish species, and can be applied to estimate risks of different compounds.

We first present two case studies showing population-level effects of exposure to chlorothalonil and diazinon. Then, we show how the model could be applied to listed species by comparing the results on FHM with those of a previously published model on listed Cyprinidae. Ultimately, we show that our model could benefit ERA in two ways: (i) by simulating population-level effects for FHM that could possibly be integrated into lower-tier risk assessment; (ii) by extrapolating exposure effects to listed species populations and better guide higher-tier risk assessment.

Waterborne Presentations

Monday, November 14th, 10AM - 12:40PM, Session 5.06.T-06; Convention Center – Ballroom A 

Title:  Incorporating Climate Changes Scenarios to Understand Future Water Stress and Modeling its Impact on Consumer Product Chemical Exposure to the Environment. Authors: Raghu Vamshi, Waterborne Environmental, Inc., Brenna Kent, Waterborne Environmental, Inc., Scott Dyer, Waterborne Environmental, Inc. and LeTourneau University, Andrea Carrao, Kao USA, Inc.

Abstract:  Increased demand from a growing human population coupled with expansive evidence of climate change have intensified stresses on water availability and supply. The number of regions experiencing water stress is increasing, and municipalities are grappling with this stress by investing in water conservation, reuse, and recycling technologies. These methods will enable freshwater to be used in water stressed areas, however – they may require innovations in consumer products that are dependent on water for their function and disposal. Water stress in the U.S. was examined by evaluating datasets considering historic, current, and future water availability and use scenarios. Inclusion of anticipated climate change events required datasets that incorporated scenarios of estimated future population and per capita water use with high spatial resolution for the U.S. These datasets captured predicted temporal trends for the years 2020-2050 and were integrated with EPA’s Clean Water Needs Survey data, which represents municipal wastewater treatment plant infrastructure across the U.S. The consolidated information was used to develop current and future water use scenarios. The influence of future water use scenarios on down-the-drain chemical exposures were predicted by evaluating four consumer product chemicals with various phys/chem properties. Results from the modeling provided a quantitative forecast of the potential impacts of water stress on down-the-drain chemical exposure and potential risk. Incorporating spatial and temporal variation in water stress and its impact to the risk of chemicals in the environment, through the lens of future scenarios, provides a new dimension in the development of consumer products. Incorporating these issues into product development, now, will ensure that both consumers and the environment will be appropriately stewarded, especially considering future environmental challenges.

October 22 (Tuesday) at 2:50 pm Room 201 A - Fort Worth Convention Center

5.10.T-05 - Sampling Design and Model Selection to Evaluate the Exposure of Sunscreen and Cosmetic Ingredients to Marine and Freshwater Ecosystems using the MERCI Modeling Framework

Maura Roberts1, W. Martin Williams1, Ryan Heisler2, Scott D Dyer3, Todd Gouin4, Amelie Ott5, Nicola Hefner6, Eva Klingelmann7, Sascha Pawlowski8, Juliet Hodges9, Arnaud Franck Boivin10, Ahmed Tlili6 and Iain Davies11, (1)Waterborne Environmental, Inc., (2)International Collaboration on Cosmetics Safety (ICCS), (3)Biology & Kinesiology, LeTourneau University, (4)TG Environmental Research, United Kingdom, (5)International Collaboration on Cosmetics Safety (ICCS), New York, United States, (6) DSM- Firmenich, Switzerland, (7)Symrise AG, Germany, (8)GBP/RA, BASF SE, Germany, (9)Safety & Environmental Assurance Centre, Unilever, United Kingdom, (10)L'Oréal, France, (11) PCPC (Personal Care Products Council)

Abstract

Sampling design and model selection for environmental risk assessment are guided by the relevant fate and transport processes, and ultimately, by the specific study questions pertaining to exposure. A tiered modeling framework called MERCI (Models to Evaluate direct Release of Cosmetic Ingredients into natural waters) has been proposed and tested to evaluate the potential environmental exposure of marine and freshwater organisms to ultraviolet radiation filters (UV filters) and cosmetic ingredients. The framework consists of four levels of assessment, ranging from simple, dilution-based screening assessments to complex, 3-dimensional circulation models and a toolbox to address uncertainty and specific questions that may arise during environmental risk assessment. This tiered modeling system includes an initial conservative screen of potential risk with minimal effort and information, and progressive tiers that introduce additional processes, input requirements, and complexity to improve the accuracy of predictions. Specific models are identified for each tier based on the environmental fate processes represented by that model, the governing equations and transparency of model code, input parameter requirements, the availability of model support, acquisition cost, and established acceptance by regulatory agencies. The selection of a particular model and model tier within the MERCI framework depends on the problem statement as well as data availability, and the hydrodynamics of the system being modeled. This presentation provides a roadmap for appropriate sampling and study design, where guidance is missing, and model selection within the MERCI framework, based on the desired captured processes and specific study questions pertaining to risk assessment. Our recommendations are based on model testing for three hydrodynamically different study sites, and sensitivity analyses conducted to identify the relative importance of model inputs.

October 23 (Wednesday) at 1:30 pm Room 202 CD - Fort Worth Convention Center

5.02.B.T-01 - Identification of Agricultural Best Management Practices Using Remote Sensing

Andy Jacobson1, Zechariah Stone1, Nicholas Guth1, Maura Roberts1, Sarah Terrell1 and Richard Brain2, (1)Waterborne Environmental, Inc., (2)Syngenta Crop Protection LLC

Abstract

The United States (US) Environmental Protection Agency (EPA) has proposed a menu of runoff mitigation measures, as part of both their Endangered Species Act (ESA) workplan and their draft herbicide strategy, to protect listed species identified as potentially at risk from predicted pesticide exposures, based on the Agency’s screening-level, risk assessment approach. To evaluate the potential ramifications of the Agency’s proposed mitigation measures, an inventory of existing, agricultural best management practices (BMPs) for pesticide runoff in the contiguous US is needed. However, due to the number of funding sources available for conservation practice implementation, including federal, state, local, non-governmental organization (NGO), and private sector sources, as well as the fact that agricultural BMPs are often voluntarily adopted by growers without the support of conservation programs or funding, it is impossible to get an accurate accounting of implemented BMPs. Furthermore, federal and state reporting of BMP adoption/implementation is often limited to state-level aggregation, or county-level at best.

Therefore, due to recent improvements in satellite imagery, in both resolution and re-visit period, remote sensing and artificial intelligence (AI) were utilized to develop a comprehensive system for the unsupervised identification of existing, implemented agricultural BMPs. While a remote sensing approach may not be applicable to all agricultural BMPs, it can be used globally to improve future inventories by identifying both permanent (e.g., grassed waterways, terraces) and non-permanent (e.g., cover crops, conservation tillage) practices. Using existing datasets of identified BMPs and their corresponding locations, the developed system was trained, tested, and evaluated based on its accuracy for BMP identification. Ultimately, the BMP identifications resulting from this developed system may be utilized to evaluate the potential ramifications of the EPA’s proposed menu of mitigation measures, as well as to refine future pesticide risk assessments.

Waterborne Short Course

Sunday, November 13th, 1 - 5PM – Convention Center – 303

Training Course 08: Down-the-Drain Disposal: Environmental Exposure and Risk Assessment for Formulated Consumer Products. Chairs: Ryan Heisler, American Cleaning Institute, Raghu Vamshi, Waterborne Environmental, Inc.

Abstract: Formulated household and personal care products have become omnipresent, with our reliance on many of these products for long-term health, comfort, and safety. These products have also garnered the attention of regulators and researchers because of their widespread use and disposal. The chemical safety of formulated consumer products is a high priority for product manufacturers and ingredient suppliers who seek to ensure a clean and healthy future. One accepted method used to ensure the environmental safety of formulated products is applying risk assessments based on chemical hazards and their potential exposure. 

Potential exposure estimations include environmental (ecological) exposures through releases to aquatic environments, air, or soil. This short course aims to detail the methods used by product manufacturers and regulators to assess environmental exposures associated with formulated consumer products such as home and personal care products to understand related risks of their disposal, post-use, into the aquatic environments, i.e., U.S. surface waters. The focus will be on the fundamentals of risk assessment, emphasizing tiered aquatic environmental exposure assessment. Applications will include both lower (Tier I) and higher tier (Tier II) probabilistic modeling of environmental exposures in aquatic environments across regional and national geographies.

Waterborne Presentations

Monday, November 14th, 10AM - 12:40PM, Session 5.06.T-06; Convention Center – Ballroom A 

Title:  Incorporating Climate Changes Scenarios to Understand Future Water Stress and Modeling its Impact on Consumer Product Chemical Exposure to the Environment. Authors: Raghu Vamshi, Waterborne Environmental, Inc., Brenna Kent, Waterborne Environmental, Inc., Scott Dyer, Waterborne Environmental, Inc. and LeTourneau University, Andrea Carrao, Kao USA, Inc.

Abstract:  Increased demand from a growing human population coupled with expansive evidence of climate change have intensified stresses on water availability and supply. The number of regions experiencing water stress is increasing, and municipalities are grappling with this stress by investing in water conservation, reuse, and recycling technologies. These methods will enable freshwater to be used in water stressed areas, however – they may require innovations in consumer products that are dependent on water for their function and disposal. Water stress in the U.S. was examined by evaluating datasets considering historic, current, and future water availability and use scenarios. Inclusion of anticipated climate change events required datasets that incorporated scenarios of estimated future population and per capita water use with high spatial resolution for the U.S. These datasets captured predicted temporal trends for the years 2020-2050 and were integrated with EPA’s Clean Water Needs Survey data, which represents municipal wastewater treatment plant infrastructure across the U.S. The consolidated information was used to develop current and future water use scenarios. The influence of future water use scenarios on down-the-drain chemical exposures were predicted by evaluating four consumer product chemicals with various phys/chem properties. Results from the modeling provided a quantitative forecast of the potential impacts of water stress on down-the-drain chemical exposure and potential risk. Incorporating spatial and temporal variation in water stress and its impact to the risk of chemicals in the environment, through the lens of future scenarios, provides a new dimension in the development of consumer products. Incorporating these issues into product development, now, will ensure that both consumers and the environment will be appropriately stewarded, especially considering future environmental challenges.

Wednesday, November 16th, 10AM - 12:40PM, Session 5.18.T-08; Convention Center –304/305 

Title:  SolBeePop: Assessing Risks of Pesticide Exposures to Populations of Solitary Bees in Agricultural Landscapes, a Modeling Approach. Authors: Amelie Schmolke, Waterborne Environmental, Inc., Nika Galic, Syngenta Crop Protection, Vanessa Roeben, Bayer Crop Science, Thomas G. Preuss, Bayer Crop Science, Mark Miles, Bayer Crop Science, Silvia Hinarejos, Sumitomo Chemical.

Abstract: Solitary bees, including both wild and managed populations, are important pollinators of crops and wild flower communites. Solitary bees can potentially be exposed to pesticides via multiple routes of exposure which may differ between species and between solitary bees and the Western honey bee (Apis mellifera) which is currently used as surrogate for risk assessments across bee species. Species-specific traits may additionally interact with the potential for exposures and effects, including, for instance, phenology, reproductive rates and flower preferences. We are presenting a population model for solitary bees in agricultural landscapes, SolBeePop. The model was developed to simulate a variety of species by using species-specific ecological traits as model parameterizations. Model parameterizations for several species (Osmia bicornis, O. cornifrons, O. cornuta, O. lignaria, Megachile rotundata, Nomia melanderi, and Eucera (Peponapis) pruinosa) were compiled from the literature whereby data availability varied by species. The model can simulate the diverse life cycles of the species and can be used to explore the importance of uncertainties in data to the population dynamics. Exposures to a pesticide through multiple exposure routes can be considered, such as nectar, pollen, and nesting materials. Effects are implemented using a simplified toxicokinetic-toxicodynamic model, BeeGUTS, adapted specifically for adult bees while an exposure-response functions is applied to simulate effects to developing in-nest life stages. We calibrated and validated the model with control data from semi-field studies conducted with O. bicornis. We applied the model across the model species to assess the impacts of different trait combinations on population dynamics, exposures and population-level effects in relevant landscape scenarios. The model provides a valuable tool for higher-tier pesticide risk assessments across species of solitary bees in agricultural landscapes.

Wednesday, November 16th, 10AM - 12:40PM, Session 5.11.T-03; Convention Center –Ballroom B 

Title: Modeling pesticide effects on multiple threatened and endangered Cyprinid fish species to support decision making. Authors: Chiara Accolla, Waterborne Environmental, Inc., Amelie Schmolke, Waterborne Environmental, Inc., Andy Jacobson, Waterborne Environmental, Inc., Colleen Roy, Waterborne Environmental, Inc., Valery E. Forbes, University of Minnesota, Richard Brain, Syngenta Crop Protection, Nika Galic, Syngenta Crop Protection.

Abstract: Mechanistic models are invaluable in ecological risk assessment (ERA) because they facilitate extrapolation of organism-level effects to population-level effects while accounting for species life history, ecology, and vulnerability. Therefore, models are particularly useful for assessing potential risks of pesticides to threatened and endangered species, for which data collection and laboratory tests are challenging or impossible. We developed a model framework to compare the potential effects of the fungicide chlorothalonil across several listed species of cyprinid fish and explored species-specific traits of importance at the population level.  The model is an agent-based model based on the dynamic energy budget (DEB) theory. As a case study, we considered four listed species of Cyprinidae: Humpback chub (Gila cypha), Spikedace (Meda fulgida), Topeka shiner (Notropis topeka), and Devils River minnow (Dionda diaboli). Potential direct lethal and/or sublethal effects on individual fish were considered as well as indirect effects through reduction in prey. We calibrated four effect sub-models to account for different effect pathways based on experimental data from exposure to chlorothalonil. Toxicokinetic-toxicodynamic models were used for representing direct effects, whereas indirect effects were described by decreasing food availability. Exposure profiles were constructed based on a degradate (hydroxychlorothalonil), given the relatively short half-life of the parent chlorothalonil.  We performed two kinds of simulations (i) we applied all effect sub-models simultaneously and considered different exposure magnification factors (EMFs); (ii) we sequentially added the different effect sub-models to test their relative importance. We demonstrated that exposure affected population dynamics depending on species-specific life-history traits and processes (i.e., density dependence). Different EMFs were required to achieve a comparable population decrease across species. Moreover, sequentially adding effect sub-models resulted in different outcomes depending on the interplay of life-history traits and density-dependent compensation effects. We conclude by stressing the importance of using models in ERA to account for species-specific characteristics and ecology, especially when dealing with listed species and in accordance with the necessity of reducing animal testing.

Waterborne Posters

Title: Mechanistic effect models: A brief history to highlight benefits and obstacles in using them for chemical risk assessment. Authors: Chiara Accolla, Waterborne Environmental, Inc., Valery E. Forbes, University of Minnesota, Nika Galic, Syngenta Crop Protection, Sandy Raimondo, US Environmental Protection Agency, Amelie Schmolke, Waterborne Environmental, Inc., Maxime Vaugeois, Syngenta Crop Protection.

Abstract: Although mechanistic effect models are widely recognized as potentially valuable tools, they are still not regularly used or accepted for regulatory Ecological Risk Assessments (ERA). There are several possible reasons for this, including the lack of trust and transparency in the modeling process, but more importantly the mismatch between the endpoints they yield and those that have been traditionally applied and the lack of “bright lines”.

This presentation aims to open a thorough discussion among all the parties involved in the risk assessment process to understand how we could enhance the use of mechanistic effect models in different regulatory contexts. To this end, we present a brief history of mechanistic effect models for ERA and give an overview of their goals within the ERA context. We show some examples of effect models developed within different stakeholders (US EPA, academia, business) and highlight their similarities and differences. 

In this context, we suggest focusing on a few important points:

  • Define standardized outputs of interest, such as population abundance, population decline, recovery, or extinction probability and how these outputs can be applied in decision making.
  • Determine which and how environmental scenarios  should be applied across models.
  • Find agreement on those model features deemed essential to represent populations such that risks can be adequately assessed.
  • Underline the importance of identifying model use and objectives before model development and ensure transparency and consistency in the overall process. 

We also tackle some common issues linked to model acceptance and conceptual misunderstandings. For example, models are currently often newly developed or adapted for the context of a specific risk assessment and thus, include different processes relevant to the system and objectives. This reduces consistency across models and increases the effort involved in reviewing them.  Moreover, there are different points of view regarding how to best use data obtained from surrogate species, how to deal with data gaps, and how to address model uncertainty. In conclusion, we hope to foster dialog among stakeholders to ensure the use of the best available science in a standardized way to support ecological risk assessments of chemicals.

Title: Analysis of the Fate and Transport of SARS-CoV-2 in Wastewater and Surface Waters in the US Using iSTREEM®, Authors: Raghu Vamshi, Waterborne Environmental, Inc., Brenna Kent, Waterborne Environmental, Inc.

Session title: 4.14 – Innovative Analytical Approaches for Understanding Environmental Contaminants of Emerging Concern

Abstract:  The ongoing pandemic of coronavirus disease 2019 (COVID‑19) caused by severe acute respiratory syndrome coronavirus 2 (SARS‑CoV‑2) is taking a huge toll on humankind.  Infected people excrete the virus through their feces which is conveyed to wastewater treatment plants (WWTP) where its genetic material, RNA, can be detected.  SARS‑CoV‑2 may remain active while being transported in water through the WWTP and into receiving waters.  Therefore, it is critical to determine the distance the virus may travel and whether surface water, including drinking water, is at risk.  Modeling the fate of viruses in WWTPs and surface water on a national level could be an additional evaluation of monitoring efforts.   iSTREEM®, a tool used for modeling the fate and transport of down-the-drain materials, was used to estimate viral concentrations in effluent at WWTPs and surface water for the continental U.S.  Inputs for modeling included the viral load, removal in WWTPs, and in-river decay which were based on monitoring data, current literature, and expert opinions.  This analysis indicated that WWTPs are highly efficient in removing SARS‑CoV‑2.  Residual RNA fragments were either removed or diluted in the surface waters and were not measured above current detection limits.  Treatment of drinking water will result in even greater loss of viral fragments, if present, indicating that SARS‑CoV‑2 most likely does not pose a health risk in the U.S. via drinking water.  This is the first study to provide quantitative data at a national scale to support these claims.

Title: Evaluating Subsurface Movement of PFAS Compounds Using Both One and Multi-Dimensional Modeling Approaches, Authors: Colleen Roy, Waterborne Environmental, Inc., Brenna Kent, Waterborne Environmental, Inc., Gerco Hoogeweg, Waterborne Environmental, Inc., Amy Ritter, Waterborne Environmental, Inc., Raghu Vamshi, Waterborne Environmental, Inc.

Session title: 4.14 – Innovative Analytical Approaches for Understanding Environmental Contaminants of Emerging Concern

Abstract:  Per- and polyfluoroalkyl substances (PFAS) are used in in numerous consumer products and industrial applications. Not only are PFAS widely used, but they also cover a vast chemical group with thousands of distinct compounds. Because of this, they have become a ubiquitous occurrence in the environment. Several small and large-scale monitoring programs have shown widespread presence of these compounds in air, surface and ground water, and soil media. As awareness of these chemicals continues to increase, concerns due to their persistence and toxicity to environmental and human health also grows. Through their PFAS Strategic Roadmap, USEPA has been prioritizing ongoing work to better understand and eventually reduce the potential exposure and risks caused by these chemicals. USEPA has also included 29 PFAS to be monitored under the fifth Unregulated Contaminant Monitory Rule (UCMR 5) between 2023 and 2025. In addition to monitoring data, reliable modeling tools to evaluate the fate and transport of these chemicals are critical to the development of risk assessment and remediation strategies. To date, limited work has been done to better understand the fate and transport of these complex chemicals in the environment using existing modeling approaches. Rising public interest and increasing regulatory action has made the need for modeling an important next step in advancing the understanding of these persistent chemicals. This work will focus on applying standard modeling approaches to understand the fate and transport of PFAS. Two models, HYDRUS and GeoPEARL, were used to simulate PFAS measured at contaminated sites. Previously, these models were applied to simulate PFOA and PFOS in groundwater at an airport which had been used as firefighter training site, exposing the area to AFFF. This work has been expanded to include sites with other potential PFAS sources such as landfills. Results from modeling were compared with available groundwater monitoring data for these sites. The practical utility of the standard modeling approaches for application to address the PFAS challenges over small and large geographies are discussed.

Title: Right-Sizing UV Filter Exposure Estimates – A Critical Need. Authors: Nikki Maples-Reynolds, Waterborne Environmental, Inc., Scott Dyer, Waterborne Environmental, Inc and LeTourneau University, Brenna Kent, Waterborne Environmental, Inc., Colleen Roy, Waterborne Environmental, Inc., Raghu Vamshi, Waterborne Environmental, Inc., W. Martin Williams, Waterborne Environmental, Inc., Todd Gouin, TG Environmental Research, Nicola Hefner, DSM, Eva Klingelmann, Symrise, Sascha Pawlowski, BASF, Amelie Ott, Cosmetics Europe.

Session title: 2.06 – Detection, toxicity and environmental risk of UV filters in aquatic ecosystems

Abstract:  Per- and polyfluoroalkyl substances (PFAS) are used in in numerous consumer products and industrial applications. Not only are PFAS widely used, but they also cover a vast chemical group with thousands of distinct compounds. Because of this, they have become a ubiquitous occurrence in the environment. Several small and large-scale monitoring programs have shown widespread presence of these compounds in air, surface and ground water, and soil media. As awareness of these chemicals continues to increase, concerns due to their persistence and toxicity to environmental and human health also grows. Through their PFAS Strategic Roadmap, USEPA has been prioritizing ongoing work to better understand and eventually reduce the potential exposure and risks caused by these chemicals. USEPA has also included 29 PFAS to be monitored under the fifth Unregulated Contaminant Monitory Rule (UCMR 5) between 2023 and 2025. In addition to monitoring data, reliable modeling tools to evaluate the fate and transport of these chemicals are critical to the development of risk assessment and remediation strategies. To date, limited work has been done to better understand the fate and transport of these complex chemicals in the environment using existing modeling approaches. Rising public interest and increasing regulatory action has made the need for modeling an important next step in advancing the understanding of these persistent chemicals. This work will focus on applying standard modeling approaches to understand the fate and transport of PFAS. Two models, HYDRUS and GeoPEARL, were used to simulate PFAS measured at contaminated sites. Previously, these models were applied to simulate PFOA and PFOS in groundwater at an airport which had been used as firefighter training site, exposing the area to AFFF. This work has been expanded to include sites with other potential PFAS sources such as landfills. Results from modeling were compared with available groundwater monitoring data for these sites. The practical utility of the standard modeling approaches for application to address the PFAS challenges over small and large geographies are discussed.

Title: A New Software Tool for Promoting Standardization of Conceptual Diagrams for Mechanistic Effect Models. Authors: Kristin Crouse, University of Minnesota; Valery Forbes, University of Minnesota; Chiara Accolla, Waterborne Environmental, Inc.; Thomas Banitz, Helmholtz Centre for Environmental Research - UFZ, Germany; Nika Galic, Syngenta Crop Protection, Switzerland; Volker Grimm, Helmholtz Centre for Environmental Research - UFZ, Germany;  Sandy Raimondo, Office of Research and Development (ORD), U.S. Environmental Protection Agency; Amelie Schmolke, Waterborne Environmental, Inc.; and Maxime Vaugeois, Syngenta Crop Protection.

Session title: 5.03 – Benefits and Obstacles in Using Mechanistic Effect Models for Chemical Risk Assessments

Abstract: Due to lack of guidance, risk assessors and risk managers have shown reluctance to use mechanistic effect models for ecological risk assessment. Recent efforts have promoted guidance in documentation (e.g., ODD, TRACE), evaluation (e.g., TRACE, Pattern-Oriented Modeling) and development (e.g., Pop-GUIDE). However, guidance is still needed for how to build conceptual model diagrams, which visually communicate the salient details of a model to a general audience. Currently, modelers create conceptual model diagrams using a wide variety of approaches, such that two modelers depicting the same model would likely yield vastly different diagrams. To reduce individual bias in diagram construction, we propose a new software tool that produces standardized and consistent diagrams for any kind of mechanistic effect model. Users will visit a public webpage and answer a series of questions about their model. The software will generate a visual diagram from these responses, which the user can download for free. The diagram will include information on key elements of a mechanistic effect model, including: (1) properties of the environment such as spatial heterogeneity, external drivers, or chemical exposure; (2) organism characteristics such as life-history traits, behavior, and energetics; (3) other key features such as density dependence and stochasticity; and (4) important model outputs such as abundance, biomass, and more. In the generated diagram, these elements are both listed as text and depicted visually to show their connections, thus highlighting the main features of the model while being consistent across models. We expect that our standardized diagrams will be quick and simple to understand, capturing the key features of the model without going into too much detail, and be applicable to a wide range of model types and complexities. Ultimately, these improvements will promote transparency in model descriptions and will cultivate trust among modelers, assessors and managers.