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.
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.
A Risk Assessment Process for Establishing Negligible Risk Earlier in National-Scale Endangered Species Assessments
Matt Kern, Katherine Kapo, Nathan Snyder, Josh Amos, Megan Sebasky, Dan Perkins, Gregg Hancock and Amelie Schmolke (Waterborne Environmental). “A Risk Assessment Process for Establishing Negligible Risk Earlier in National-Scale Endangered Species Assessments”. Presentation. CLA RISE. April 2016.
PostersAgriculture and Food2016
Modeling Watershed-Scale Cover Crop Impact on Nitrate Availability and Transport
Presented at the 2016 Hypoxia Task Force Meeting in St. Louis, MO.
Daniel Perkins, PhD., Rohith Gali, PhD. (Waterborne) and Caroline Wade (Illinois Corn Growers Association).”Modeling Watershed-Scale Cover Crop Impact on Nitrate Availability and Transport“.Poster. Hypoxia Task Force Spring 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.
Three Estuarine Mixing Scenarios for Pesticide Risk Assessment
Session: Environmental Fate, Transport & Modeling of Agriculturally-Related Chemicals
Time: 1:30PM – 1:55PM
Location: Regency Ballroom C1 – Loews Philadelphia Hotel
The US EPA, the National Marine Fisheries Service, the US Fish & Wildlife Service, and pesticide registrants are focused on accurately assessing the potential risks of pesticides to threatened and endangered species. Currently, the EPA’s Office of Pesticide Programs assesses risk with a modeling system, the Pesticide in Water Calculator (PWC), which couples the daily-time-step, field-scale numerical-solution model Pesticide Root Zone Model (PRZM) with the Variable Volume Water Model (VVWM). The VVWM has various receiving water mixing scenarios, including estuarine and coastal zones, but none of the scenarios consider tidally-driven sea water stratification and sediment transport processes. This creates a significant gap in understanding the exposure component of pesticide risk assessment, since the toxicology data component – – pesticide toxicity to marine and estuarine organisms – – is usually complete and available. We propose to create three distinct marine/estuarine mixing scenarios for incorporation into the VVWM: salmonids in the Pacific Northwest, coral in the Hawaiian Islands or the Florida Keys, and crustaceans in the Chesapeake Bay. The diverse scenarios include a coastal embayment or a marine shoreline, a salt wedge estuary, and a drowned eroded river valley. The biology of target species will drive the development of each scenario; e.g., the coral reef embayments will not have high TSS concentrations (coral doesn’t grow in high TSS environments). A key consideration will be the exchange coefficient, i.e., the exchange of conservative substances due to tidal circulation. The full semi-diurnal tide will be considered so that times such as the slack tide period, when many of the organisms are feeding and there is low mixing, will be fully considered. The study will characterize the circulation, geometry, and aquatic chemistry of each habitat. Water, salt, and pesticide mass balances based on box model volume elements will be constructed that represent multiple vertical and horizontal segments. A key phase will be testing the models against field data for each scenario.
Stuart Cohen (Environmental & Turf Services), Louis Thibodeaux (Louisiana State University), Craig Jones (Integral Consulting), Martin Williams (Waterborne Environmental), Sandra Haefner (Environmental & Turf Services). “Three Estuarine Mixing Scenarios for Pesticide Risk Assessment”. ACS Philadelphia Presentation. August 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.
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.
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.