7th SETAC World Congress/37th SETAC North America Annual Meeting
The 7th SETAC World Congress/37th SETAC North America Annual Meeting and all business and social events will be held at the Rosen Shingle Creek Resort in Orlando, FL. This years North America SETAC meeting is special because it combines the annual NA meeting with the World Congress and it expected to draw record crowds. This 5-day event will draw more than 2,500 scientists, assessors, regulators and managers from academia, business and government, representing 40 plus countries, provides a unique networking opportunity and a chance for cross-collaboration long after the closing session.
This year we have several platform and poster presentations on our crop protection and home and personal care product work. A full list of our presentations and posters can be found here>>
On Sunday, November 6 from 1:00-5:00pm, Waterborne’s Vice President, Chris Holmes, will be partnering with American Cleaning Institute to teach the Environmental Exposure and Risk Assessment for Formulated Consumer Products short course in St. John’s 30 room. More information on this short course can be found on the SETAC website: https://orlando.setac.org/program/scientific-program/trainingcourses/
We do our best to make presentations available for download after the conference while honoring client guidance on dissemination. If you have questions about any of these presentations, please contact Casey Wisch at email@example.com.
Waterborne's Presentations & Posters
Home & Personal Care ProductsPresentations
A Framework for Dynamic Estimation of Environmental Concentrations of Microplastics in WWTP Effluents and Receiving Waters at a National Scale
Down-the-drain exposure models provide a valuable screening-level tool for estimating environmental exposure to product ingredients which are treated and discharged at municipal wastewater treatment plants. Microplastics, plastic particles smaller than 5 mm diameter, enter wastewater treatment plants (WWTP) due to a variety of sources. Exposure modeling was performed using the iSTREEM® model, a publicly-available web-based model supported by the American Cleaning Institute (www.istreem.org) which estimates spatially-explicit concentrations of chemicals in effluent and receiving waters across the U.S. WWTP influent loadings of microbeads were estimated using per-capita usage derived from market manufacture survey (Gouin et al 2015) combined with individual facility population served and flow estimates within the iSTREEM® model. The analysis used multiple values for removal during treatment based on total suspended solid removal data and a wide range of in-stream decay rates, resulting in a variety of potential environmental exposure estimates. The removal and decay rates have a non-linear effect across the varying facilities & stream segments in the US landscape. Therefore, we developed an approach which leverages the advantages of the iSTREEM® model (national scope, individual facilities, and distributions of output) with the ability to screen for potential concern based on uncertain (and dynamic) removal and decay rates. This allows for flexibility in modeling the environmental concentration of microbeads regardless of size, weight, or physicochemical properties. We developed a 2-dimensional matrix with removal rate and decay rate as the primary axes. The individual cells within the array will then correspond to a reasonable worst-case Predicted Environmental Concentration (PEC) (e.g. 95th percentile) based on the national iSTREEM® results. These concentrations are based on a proxy quantity of microbeads which can be easily scaled. Therefore, with the matrix it is possible to supply an approximate removal and decay rate for the microplastic of interest and assess the estimated exposure by scaling the matrix value using the relationship between the substance quantity of interest and the proxy. This matrix framework can be used to help inform environmental exposure assessments by readily providing concentrations based on varying model inputs on WWTP removal and in-stream decay rates for microplastics, which continues to evolve as more research is conducted.
Nikki Maples-Reynolds, Chris M. Holmes, Raghu Vamshi (Waterborne), Iain A. Davies, Beth A. Lange (Personal Care Products Council), Scott Dyer (The Procter & Gamble Company). “A Framework for Dynamic Estimation of Environmental Concentrations of Microplastics in WWTP Effluents and Receiving Waters at a National Scale.” Presentation. SETAC NA. 2016.
Developing Population Models for Pesticide Risk Assessments: A Systematic Approach (For Herbaceous Plants)
Population models have been recognized as important tools in pesticide risk assessments for species listed under the Endangered Species Act. However, not many population models for this specific purpose have been developed to date. A systematic, transparent approach to developing population models for pesticide risk assessment would ease the development of new models and the assessment and adaptation of existing models for this kind of risk assessment. We introduce a decision guide for the development of population models of herbaceous plants to be applied in pesticide risk assessment.
The guidance walks the model developer through necessary steps that consider the specific questions to be addressed by the model, the life history of the species, and the data availability for species and habitat characteristics as well as pesticide exposure and effects. The guidance can either be applied to a single species or can be used to address a group of similar species. The resulting minimal conceptual model can serve as a blueprint for the implementation of a new model or to assess the applicability of an existing model for use in the context of pesticide risk assessment.
Population- or species-level risk assessment is an extensive task given the number of species currently listed. Population models provide a tool to link population-level dynamics, species and habitat characteristics as well as exposure and effect information in a single approach. Developing such models in a systematic, transparent way will increase their applicability and credibility, reduce development efforts, and result in models that are readily available for use in risk assessments with varying compounds and exposures. We present the systematic approach for developing population models for herbaceous plant species and intend that the approach be adapted to provide model development guidance for other organism groups as well.
Amelie Schmolke*, Katherine Kapo (Waterborne Environmental), Richard Brain (Syngenta Crop Protection), Pamela Rueda-Cediel (University of Minnesota), Valery E. Forbes (University of Minnesota). “Developing Population Models for Pesticide Risk Assessments: A Systematic Approach (For Herbaceous Plants)“. Poster. SETAC NA 2016.
Approaches for Mapping the Habitat of Listed Species without Federally Declared Critical Habitat
Spatially explicit sub-county habitat for federally listed species based on defensible scientific approaches allows for greater confidence and more realism in assessing the potential risk that pesticides have to listed species. Currently, refined spatial habitat information for a large number of listed species remains unresolved. Of the nearly 1,680 listed species in the US, approximately 788 have federally declared Critical Habitat suitable for use in national scale regulatory assessments. In the draft Biological Evaluations for three organophosphate compounds published in the spring of 2016, USEPA incorporated species range maps provided by The Services to make effects determinations for nearly all listed species; however, these range maps are not yet publicly available.
This poster presents a study to explore approaches for efficiently generating spatial habitat using current data sources and techniques. While the habitat generated cannot represent “Critical Habitat”, it should represent the physical and biological features occupied by the species. The goal is spatial data of appropriate accuracy and resolution for use with potential pesticide use sites in national-scale pesticide risk assessments. The science applied must be transparent and instill confidence in stakeholders that the data are representative and protective of the listed species.
Federal Registry, USFWS reports, and NatureServe species profiles are highlighted as sources of textual habitat descriptions to inform both suitable habitat delineation and subsequent refinements to represent the often localized distributions of many endangered species. Tiered habitat maps are presented that show a tapering view from range to the biophysical habitat parameters selected to represent suitable habitat. Several terrestrial, plant, and/or aquatic species across taxonomic groups are showcased.
Josh Amos, Megan Sebasky*, Brian Kearns (Waterborne Environmental), Steve Kay (Pyxis).”Approaches for Mapping the Habitat of Listed Species without Federally Declared Critical Habitat“. Poster. SETAC NA. 2016.
Assessment of Available Monitoring Data and Modeled EEC Values for an Herbicide (Linuron) in the US and Canada
The purpose of his study was to compile a dataset of monitoring data for an herbicide (linuron) used in North America to create a geospatial illustration of the water monitoring locations and to compare these results to the outputs of standard Tier 2 models. Water quality monitoring records were collected for a 25-year period (1986 – 2015). Over 115,000 sample results were obtained for Canada and the US. Monitoring data for the U.S. was available primarily online. Much of the information for Canada was requested from regulatory agencies and other organizations, and, to a lesser degree, available online. Of the 115,000+ records that were collected 89% are associated with the US and 11% of the monitoring data is for Canada. A majority of the data in both the Canada and the US are for surface water (~60%) and for groundwater (~39%), while results for drinking water are less commonly reported (0.02%). About 1% of the monitoring data indicated that the herbicide was detected. In addition to standard percentile assessments, geo-spatial statistics were applied to identify ranges of sampling density for monitoring and to determine if spatial-temporal trends are present in the data. Monitoring data were compared to standard USEPA and PMRA modeling scenarios. The results indicated that no correlation exists between modeled data and observed data for linuron.
Gerco Hoogeweg*, Isha Khanijo, Stephanie Herbstritt (Waterborne), Kevin Henry, Luis Castro, and Jonathan Akins (TKI). “Assessment of Available Monitoring Data and Modeled EEC Values for an Herbicide (Linuron) in the US and Canada“. Presentation. SETAC NA. 2016.
An Evaluation of Endpoints from Benthic Invertebrate Chronic Toxicity Tests Based On Draft US FIFRA Guidance – Part II
Session: Science of Sediment Toxicity Testing: Method Advances, Interpreting Results and Use of Data in Ecological Risk Assessments
Session Start Time: 8:00AM
Location: Exhibit Hall
Authors: Jennifer Gates*, Mark Cafarella (Waterborne), Theodore Valenti (Syngenta), Kent Kabler (Syngenta), Alan Samel (Dupont), Alan Jones (Dupont), John Green (Dupont), Jane Staveley (Exponent), Bibek Sharma (FMC), Sean McGee (Bayer), Matt McCoole (Bayer), Jiafan Wang (BASF), Maike Habekost (BASF), Hank Krueger (Wildlife International), Susan Thomas (Wildlife International), Michael Bradley (Smithers), Christian Picard (Smithers), Jeff Giddings (CSI), Imad Saab (CropLife)
On October 26, 2007, sediment chronic toxicity testing with benthic aquatic invertebrates became a conditional requirement as part of the Office of Pesticide Program’s ecological effects data requirement contained in 40 CFR Part 158 Subpart G. Studies are now required for any pesticides with soil partition coefficient (Kd) ≥ 50, log Kow ≥ 3, or Koc ≥ 1000. Due to the novelty and complexity of the study designs, it is important to gain a critical understanding of the relative sensitivities of required test endpoints within and among tests. At the 2015 SETAC North America annual meeting, the CropLife America (CLA) Ecotoxicology Work Group Sediment team presented a poster detailing key findings from a sediment toxicity testing database that was compiled by CLA. For the Chironomus dilutus life-cycle tests, larval survival, growth and emergence were the most sensitive parameters, whereas endpoints based on reproduction or adult survival (i.e., number of days to death) were consistently less sensitive. For chronic sediment studies with amiphipods (Hyalella azteca and Leptocheirus plumulosus), survival, growth, and reproduction proved to be important parameters to measure and each parameter yielded the most sensitive endpoint for certain studies. This presentation will provide an update and recommendations for streamlining relevant endpoint selection, as well as more closely consideration of the variability within control responses and subsequent implications.
Jennifer Gates, Mark Cafarella (Waterborne Environmental), Theodore Valenti (Syngenta), Kent Kabler (Syngenta), Alan Samel (Dupont), Alan Jones (Dupont), John Green (Dupont), Jane Staveley (Exponent), Bibek Sharma (FMC), Sean McGee (Bayer), Matt McCoole (Bayer), Jiafan Wang (BASF), Maike Habekost (BASF), Hank Krueger (Wildlife International), Susan Thomas (Wildlife International), Michael Bradley (Smithers), Christian Picard (Smithers), Jeff Giddings (CSI), Imad Saab (CropLife). “An Evaluation of Endpoints from Benthic Invertebrate Chronic Toxicity Tests Based On Draft US FIFRA Guidance – Part II“. Poster. SETAC NA. 2016.
A Spatially-Distributed Modeling Framework to Integrate Effects of Agricultural Best Management Practices: A Midwest Case Study
The federal pesticide risk assessment framework does not currently quantitatively account for off-field transport and exposure effects of best management practices (BMPs). Within the agricultural landscapes of the U.S., numerous structural and cultural BMPs are currently in place, mostly developed from NRCS programs to address agrichemical and soil loss reduction, natural resource conservation, and yield increase. In this work, a Midwest watershed was used as a case study for development of a spatially-distributed modeling approach to quantitatively evaluate potential impact of pesticide reduction (load and/or concentration) from multiple BMPs at multiple scales. This framework included a hydrologic and chemical transport model that was paired with stream flow and routing components to represent upland hydrologic processes, land management practices, and a flowing, receiving water body. Within the upland model, specific sub-areas were modeled separately to represent various structural BMPs, based on their physical location. Furthermore, cultural BMPs were also incorporated into the upland model to different degrees to evaluate model sensitivity. A baseline scenario was developed and used to define comparative difference between addition (adoption) and elimination of BMPs in a step-wise fashion. As part of the baseline scenario, relevant literature values and publically-available environmental data were used to inform model parameterization. This modeling framework can be used to explore how BMPs may be considered in a regulatory framework, addressing issues such as: BMP adoption rate and viability, weather-dependent behavior, and frequency and extent of BMP efficacy.
Dan Perkins, Rohith Gali, Matt Gloe, Brian Jacobson (Waterborne), Clint Truman (Syngenta). ” A Spatially-Distributed Modeling Framework to Integrate Effects of Agricultural Best Management Practices: A Midwest Case Study.” Poster. SETAC NA. 2016.
Advances in the Refined National-Scale Drinking Water Assessment Framework: Case Study Chlorpyrifos
In the US pesticide regulatory scheme for human dietary exposure, estimates of the surface-derived drinking water contribution are assessed with simple scenario-based modeling techniques. Such estimates can be a useful and conservative approach in a tiered risk assessment to systematically eliminate potential concern; however, the limited conclusions that can be reached are often not adequate to address the true extent of potential exposures. The current work focuses on advances in national-scale drinking water concentration estimation techniques, using chlorpyrifos as a case study. The method incorporates spatially-distributed environmental and management information in a risk framework at the watershed (HUC12) scale. Concepts of standard scenarios to create conservative, regionally representative (at an extent wider than HUC12) estimates of exposure patterns were applied and then were distributed at the HUC12 watershed scale by matching them with HUC12-specific cropping patterns derived from five years of cropland data layer (CDL) data. As a conservative first approximation, it was assumed that a drinking water source co-occurs within every HUC12 where applications were made to labeled crops. In this way, HUC12-specific exposure estimates were derived for all chlorpyrifos-labeled crops. Then, county-level community water system (CWS) locations were included to eliminate risk concern from HUC12 watersheds that did not co-occur with a CWS. Results from this first approximation eliminated concern in 83% of HUC12 watersheds with labeled crop(s). The impact of refinements and assumptions on the remaining 17% of HUC12 watersheds was further explored. Potential refinements included higher-resolution rainfall, soils, runoff and erosion data inputs, more realistic environmental fate, application timing and application type information, and percent crop treated. Significant impact was observed from the inclusion of these refinements, with at least 92% of the remaining HUC12 watersheds yielding a conclusion of no concern. Characterization of potential risk in a spatially-distributed fashion increases risk characterization accuracy/certainty because of the inclusion of best-available data to inform estimates of exposure and co-occurrence. In conclusion, it was discovered that spatially-distributed environmental and management factors must be considered to increase certainty and characterize potential risk, rather than relying solely on a scenario-based approach.
Dan Perkins*, Nathan Snyder, Josh Amos, Kendall Jones (Waterborne), Patrick Havens (Dow AgroSciences), Nick Poletika (Risk Analysis Solutions). “Advances in the Refined National-Scale Drinking Water Assessment Framework: Case Study Chlorpyrifos.” Poster. SETAC NA. 2016.
Exposure Assessment Modelling Approach to Non-Target Plants Through Runoff from Agricultural Fields
The U.S. EPA uses the screening model, TerrPlant, to estimate exposure to non-target terrestrial plants from a single application of pesticide. Audrey III is a higher tier exposure model that has been developed by U.S. EPA to estimate exposure to plants in a Plant Exposure Zone (PEZ). The objective of this study was to investigate the magnitude and likelihood of exposure of non-target plants to pesticide residues through runoff from agricultural field to an adjacent PEZ. TerrPlant and AUDREYIII will be compared to two vegetative filter models: PRZM-Buffer and VFSMOD. PRZM-Buffer is a modified version of the Pesticide Root Zone Model (PRZM), a rainfall-runoff simulation model, to simulate pesticide fate and transport in a PEZ. VFSMOD is a vegetative filter strip (VFS) model designed to simulate VFS processes to remove sediment and pesticides from field runoff/erosion. Current EPA Tier II scenarios for PRZM were used to represent main field simulations. Movement of pesticide through the PEZ and the concentrations for the segments were modeled with the PRZM-Buffer model and VFSMOD. Results from these two models will be compared to each other and to U.S. EPA models TerrPlant and AUDREYIII. Multiple widths of buffers were assessed to determine distance required for soil concentrations to drop below level of concern for non-target crop.
Amy Ritter, Mark Cheplick, Dean Desmarteau, Nathan Snyder (Waterborne Environmental). “Exposure Assessment Modelling Approach to Non-Target Plants Through Runoff from Agricultural Fields.” Poster. SETAC NA. 2016.
Application of a Population Model for a Threatened Plant Species in Herbicide Risk Assessment
Extrapolating from organism-level endpoints, as generated from standard pesticide toxicity tests, to populations is an important step in threatened and endangered species risk assessments. Population modeling approaches can be used as tools to estimate potential risk from pesticides to sensitive populations by integrating multiple sub-lethal and lethal effects simultaneously and by accounting for differences in species’ life histories.
We apply a population model for a threatened herbaceous plant species, Boltonia decurrens, to estimate the potential population-level impacts of different herbicides. We combine conservative in-habitat exposure scenarios with dose-response curves for growth and survival of standard test species, and apply those in the species-specific model. In the model, a yearly herbicide exposure from drift is linked to dose-response curves derived from vegetative vigor tests and affects established plants. Dose-response curves derived from seedling emergence tests are applied to model the effects of exposure from herbicides transported via runoff to emerging seedlings. Exposures are distributed across the simulated habitat applying the RegDISP model for spray drift, and a combination of the Pesticide Root Zone Model (PRZM) and the Vegetative Filter Strip Model (VFSMOD) for runoff. The distributed exposure modeling approach makes it possible to assess potential effects of herbicides on plant populations growing in habitats that border chemical use areas/fields and can be used to assess the effectiveness of mitigation measures such as in-field spray buffer zones.
We show that responses of organism-level endpoints are not proportional to modeled population-level effects of pesticides. Specifically, comparison of dose-response curves from standard toxicity test species with the output of the population model demonstrates that the most sensitive organism-level endpoint is not predictive of population-level impacts. In addition, the model results suggest that in-field spray buffer zones can considerably reduce potential effects on populations of B. decurrens growing at the edge of a field. Our case study presents how species-specific population models can be applied in pesticide risk assessment bringing organism-level endpoints, exposure assumptions and species characteristics together in an ecologically relevant context.
Amelie Schmolke, Dan Perkins, Amy Ritter, Dean Desmarteau (Waterborne), Richard Brain (Syngenta), Pernille Thorbek (Syngenta), Valery E. Forbes (University of Minnesota). “Application of a Population Model for a Threatened Plant Species in Herbicide Risk Assessment.” Presentation. SETAC NA. 2016.
Refined Aquatic Exposure Estimates based on Species Data from the Pilot Biological Evaluations
The draft biological evaluations (BEs) released by USEPA assessing three pilot chemicals utilized a regionalized assessment methodology for assessing exposure to endangered species living in aquatic environments. Aquatic exposure was assessed using several fixed receiving water (habitat) dimensions, referred to as aquatic bins. The BEs also included a detailed summary of USFWS information regarding habitat waterbodies and species locations. In this presentation, a tiered exposure assessment methodology is proposed that builds off of the scenario based exposure methodologies, but also extends beyond and utilizes species relevant data as early in the process as feasible. Refinements addressing habitat hydrodynamics with appropriate modeling approaches will be presented as refinements using readily available modeling tools and conservative assumptions. In the presentation of results, USEPA clearly identified extreme exposure predictions and expressed desire for ideas on refinements. This presentation seeks to answer that call in a species relevant and specific manner that allows for scaling to the appropriate chemical use footprint with focus on species habitat area. Results allow for use in screening level deterministic risk assessments. They can be further integrated with surrogate species dose response curves or sensitivity distributions for a species focused probabilistic risk expression. Temporal analysis could also be derived from the results. Implementing a species focused analysis framework using actual habitat data to inform model refinements also provides the opportunity to incorporate mitigating factors in the exposure assessment. Model tools should incorporate naturally occurring landscape mitigating factors (i.e. landscape based treatment buffers from listed stream habitats, percent crop area) as well as label or management based mitigation measures (i.e. drift buffers or protected lands). The goal of a national assessment should be to generate relevant exposure estimates by including best available data in a pragmatic way.
Nathan Snyder, Raghu Vamshi, Josh Amos, Amy Ritter, Daniel Perkins, Ph.D., Kendall Jones, Rohith Gali, Ph.D. (Waterborne). “Refined Aquatic Exposure Estimates based on Species Data from the Pilot Biological Evaluations“. Poster. SETAC NA 2016.
Endangered Species Risk Assessment Approaches for a Data-Rich Insecticide-Carbaryl
National-scale endangered species risk assessments for crop protection products continue to be challenging due to the large amount of data and uncertainties involved in these analyses. The variety of use patterns, volume of environmental fate and ecological effects data, overall diversity and number of federally listed species, and other factors can substantially add to the complex nature of these assessments. At the same time, this volume of information greatly enhances the assessor’s ability to increase the overall reliability and relevance of the risk assessment to listed species by allowing for more specific surrogacy assignments and exposure reflecting actual use patterns in potential proximity to species habitat areas. The insecticide carbaryl is an example of a well-studied crop protection product with decades of use experience and whose rich database allows for a pragmatic and detailed endangered species risk assessment. Like most products, biological sensitivity ranges are based on factors such as mode of action, receptor sites, metabolism etc. This information is crucial to understand differences in sensitivities between and within species taxa so that toxicity data can be better related to potential effects to specific listed species. Equally important is the thorough understanding of species habitats and locations so that exposure estimates can be accurately characterized. The full range of exposures and effects must then be uniquely related to use patterns, geographies and listed species for risk to be appropriately characterized to populations. In this paper, we will demonstrate examples of how this data can be collected, analyzed and applied to a national scale risk assessment for carbaryl. The pragmatic use of these best available data will allow for a more accurate and species focused risk estimate so that resources can appropriately be directed to stressors and listed species.
Home & Personal Care ProductsPresentations
Spatial Improvements Leading to Advances in Down-the-Drain Chemical Exposure Modeling with iSTREEM® 2.0
iSTREEM® (“in-stream exposure model”) is a publicly-available web-based model (www.istreem.org) that estimates down-the-drain chemical concentrations in waste water treatment plant (WWTP) effluents, drinking water intakes (DWI), and in streams impacted by domestic waste water effluent across the continental U.S. and a number of watersheds in Canada under mean annual and low-flow (7Q10) conditions. Major upgrades to the model’s underlying data were made by incorporating higher-resolution and more current spatial datasets, leading to the release of iSTREEM® 2.0. The presentation provides an overview of the development of iSTREEM® 2.0, including how specific data needs were addressed and major assumptions considered in developing the model. The model river network was upgraded to a higher-resolution hydrologic dataset based on the USEPA and USGS NHDPlus version 2, which constitutes about 228,000 river segments totaling 243,000 river miles across continental U.S. For all the river segments, estimated mean annual flows were derived from NHDPlus, but low flows (7Q10) were exclusively developed for iSTREEM® 2.0. WWTP and associated facility level information were derived from the most recent USEPA Clean Watershed Needs Survey 2012 dataset, which includes about 13,000 facilities accounting for a total population of 175 million and effluent flow of 25,000 MGD. WWTP facilities were associated to the river network by applying techniques developed by USEPA. Enhancements to the model algorithm has made it possible to run the simulations efficiently and examine chemical exposure at a detailed spatial scale over a large geography (river basins or U.S.). Model simulation results are accessible to users in tabular (MS Excel) and spatial (MS Access) data formats for easy interpretation and further customization. A case study comparing prior version of the model and latest iSTREEM® 2.0 for the U.S will be presented to examine the impact of recent upgrades to model results – with focus on the national distribution of flows (mean and 7Q10’s), effluent PEC’s, water use, dilution factors, and receiving surface water PEC’s. The developments to iSTREEM® improves its utility as a tool to support environmental exposure assessments by a variety of users for environmental risk assessments across multiple commodity groups (personal care products, pharmaceuticals, food additives, pesticides, etc.).
Raghu Vamshi, Katherine Kapo, Chris Holmes (Waterborne), Paul DeLeo, Darci Ferrer (American Cleaning Institute). “Spatial Improvements Leading to Advances in Down-the-Drain Chemical Exposure Modeling with iSTREEM® 2.0“. Presentation. SETAC NA Orlando. 2016.
Home & Personal Care ProductsPosters
A Spatial Approach for Estimating the National Distribution of Sewer Residence Times for Wastewaters in the U.S.
Sewer residence time can have a significant influence on the environmental fate and transport of wastewater constituents, including down-the-drain household consumer product ingredients. In this study, best-available data resources and geoprocessing tools were used to develop a spatial approach for estimating the national distribution of sewer residence times for wastewaters in the U.S. Case studies estimating sewer residence times for two municipalities demonstrated that road networks could be used as a spatial proxy for sewer networks when the latter data is not available. The approach was then extrapolated to a national dataset of >3,400 wastewater treatment plant (WWTP) facilities across the U.S. to estimate the national distribution of sewer residence times, with an estimated national median sewer residence time of 3.3 hours. Sewer residence times for smaller WWTP facilities (< 1 million gallons per day) were comparatively shorter than larger facilities, however the latter comprised a greater proportion of the overall national wastewater volume. The sewer residence time distributions derived in this study can be combined with in-sewer biodegradation data to estimate WWTP influent concentrations of down-the-drain household consumer product ingredients as part of a national-scale probabilistic risk assessment.
Katherine Kapo, Raghu Vamshi, Megan Sebasky (Waterborne), Michael Paschka, Kathleen McDonough (P&G). “A Spatial Approach for Estimating the National Distribution of Sewer Residence Times for Wastewaters in the U.S.” Poster. SETAC NA 2016.
A Risk Assessment Process for Establishing Negligible Risk Earlier in National-Scale Endangered Species Assessments
The stepwise endangered species risk assessment process detailed in the Interim Approach combined with more recent approaches communicated by the Federal Agencies (hereafter referred to as “Agency Methods”) in the draft Organophosphate Biological Opinions has yielded useful insights regarding the utility and practical limitations of these methods for risk assessment screening purposes. Agency Methods, while conservative by design, do not clearly incorporate opportunities to take advantage of readily-available information and simple strategies that can optimize the screening ability of the process while maintaining adequate conservatism desired for listed species protection. When strictly following Agency Methods, the number of listed species and habitats where risk is presumed, and therefore require a jeopardy evaluation, is excessive but the level of species relevance and best use of data lacking. As a result, the effectiveness of a tiered assessment process is greatly reduced. Further, the boundary between approaches and refinements used in Step 1 (“May Affect/No Effect”) and Step 2 (“Likely/Not Likely to Adversely Affect) can become unclear and even irrelevant due to the iterative nature of risk assessment. Regardless of the formal step outlined, there is a practical continuum of refinements and approaches that can be applied to effects and exposure analyses to establish negligible risk earlier in the risk assessment. The framework and decision criteria used within the framework should not be such that “Likely to Adversely Affect” decisions are commonly reached due to arbitrary limitations without fully utilizing available species habitat and biological data, species relevant exposure estimates, and surrogate ecotoxicity data. To that end, a systematic process for efficiently and effectively determining negligible risk for species and their habitats early in an assessment is presented. The approach is based on a set of fundamental “best-practices” developed from experience in conducting listed species assessments.
Matthew Kern, Nathan Snyder, Joshua Amos, Katherine Kapo (Waterborne Environmental). “A Risk Assessment Process for Establishing Negligible Risk Earlier in National-Scale Endangered Species Assessments“. Presentation. SETAC NA 2016.