SESSION:
Advances in Aquatic and Terrestrial Plant Ecotoxicology and Risk Assessment
TITLE:
Addressing Variability in EPA-FIFRA Non-Target Terrestrial Plant Testing
AUTHOR:
Clifford Habig (Compliance Services International)
ABSTRACT:
EPA typically requires non-target terrestrial plant (NTP) testing for registration of outdoor-use pesticide products. Two laboratory greenhouse tests are generally required, seedling emergence testing and vegetative vigor testing. Testing is required on multiple species for both tests. Spacing between test concentrations ranges from 2-fold to 4-fold. Primary test endpoints include percent emergence, percent survival, and plant growth (height and weight). Point estimate test endpoints used for risk assessment are expressed as an EC25 and a NOEC for each species; the EC25 is used to evaluate potential risks to non-endangered species, while the NOEC is used to evaluate potential risks to endangered species. EC25 values for each test species are calculated using regression analysis and the NOEC is calculated using hypothesis testing compared to the controls. However, the guideline design for both tests, and particularly the seedling emergence test, often results in high variability within a test group (including the controls) and between test groups within a test. There is also frequently high variability between tests conducted under different greenhouse conditions. This high variability results in considerable uncertainty in the EC25 and NOEC values, and therefore, the resulting risk assessments. This high variability and uncertainty is generally not acknowledged in lower-tier NTP risk assessments. Clear dose-response curves may not occur with data for a given species, resulting in large confidence bounds on the EC25. Similarly, the variability may result in a poorly defined NOEC, due to either a lack of statistically significant differences despite 10-20% inhibition of a test endpoint or due to inverse dose responses, with greater effects occurring at lower test concentrations than higher test concentrations. Examples of several datasets will be presented, with discussion of different approaches and interpretations of these data sets, and how these interpretations impact the potential off-site endangered species and non-endangered species risk assessments for herbicide products.
SESSION:
Advancing Endangered Species Risk Assessment and Mitigation from National-scale to Species-centric Assessments Using 'Best Available' Data
TITLE:
AMMPS: Informing Discussions on Avoidance, Minimization, and Mitigation for Pesticides and Species
AUTHORS:
Leah Duzy, Ashlea Frank (Compliance Services International); Tony Burd (Syngenta); Lula Ghebremichael (Syngenta Crop Protection, LLC); Ya-Wei Li (Environmental Policy Innovation Center); Dan Campbell (Independent Consultant)
ABSTRACT:
Under the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA), the registration of a pesticide requires compliance with the Endangered Species Act (ESA) which includes evaluating the potential risk of the use of the pesticide on ESA-listed species and designated critical habitats. For the agencies responsible for registration and consultation, this can be an extensive exercise involving many complex datasets and processes, as demonstrated in recent draft biological evaluations and draft biological opinions from the US Environmental Protection Agency (EPA), the US Fish and Wildlife Service, and the National Marine Fisheries Service (collectively, the Services). For the pesticide registrant seeking registration, this can present an opportunity to explore ways to adequately protect ESA-listed species while also considering what is feasible for the end-user. We developed a tool that indexes factors that are important to the analysis of risk, as well as imperilment and conservation needs of each ESA-listed species. With these factors, AMMPS, a tool for informing discussions on avoidance, minimization, and mitigation for pesticides and species, sequences species so that the registrant, EPA, and the Services can have informed discussions about conservation measures that may be the most appropriate for each species in the FIFRA/ESA assessment and consultation process. The objective of this presentation is to demonstrate AMMPS using an herbicide used on cultivated land in the contiguous United States as a case study.
TITLE:
Conservation, Pesticides, and Endangered Species
AUTHORS:
Ashlea Frank, Leah Duzy (Compliance Services International); Timothy Fredricks (Bayer CropScience); John Marton (Corteva Agriscience); Tony Burd (Syngenta Crop Protection LLC)
ABSTRACT:
American farmers and ranchers play a key role in the stewardship of their land and surrounding ecosystems on which we all rely. A productive agricultural system includes pest and nutrient management techniques, many of which can be conservation practices, such as edge-of-field filter strips, that help improve and protect the soil, air, and water quality. These conservation practices can also limit the inadvertent and undesirable movement of pesticides beyond the application area thereby reducing potential pesticide exposure of surrounding habitats. The Federal Insecticide, Fungicide, Rodenticide Act Endangered Species Task Force (FESTF) is exploring how various conservation practices can serve to prevent or reduce pesticide exposure to threatened or endangered species and their designated critical habitat. The goal of the efforts being explored by FESTF is to identify options for how new and existing conservation practices and measures can be both achievable and realized within the framework of pesticide risk assessment and the Endangered Species Act. This presentation will provide an overview of FESTF’s efforts, detail a pilot program, and discuss next steps.
SESSION:
Trends in Environmental Risk Assessment of Pesticides
TITLE:
Compilation and Statistical Analysis of Pollen and Nectar Pesticide Residue Levels: Applications to Tier 1 and Refined RUDs for Pesticide Risk Assessment
AUTHORS:
Larry Brewer (Compliance Services International); Timothy Fredricks (Bayer CropScience); Silvia Hinarejos (Sumitomo Chemical Agro Europe); Max Feken (Syngenta); Timothy Joseph (Landis International, Inc.); Verissimo Sa (Dow AgroSciences); William Warren-Hicks (ECOSTAT)
ABSTRACT:
Honey bee dietary risk assessment of pesticides requires knowledge of the residue levels in nectar and pollen, either following foliar application to crops, trunk/stem injection, soil application or seed treatment. Current Tier 1 bee risk assessment in the United States relies on an exposure estimation and risk assessment model called BeeREX. This model uses a Residue Unit Dose (RUD) approach to estimate residues in nectar and pollen based on the upper‐bound pesticide residue values from US Environmental Protection Agency’s (US EPA) T‐REX model (version 1.5) of residues measured on a variety of plant matrices assembled for the purpose of dietary risk assessment in birds and mammals. Specifically, the RUD for ‘long grass’ residues are used within BeeREX as a surrogate for residues in nectar and pollen. In comparison, European Union (EU) Tier 1 risk assessment uses a database of nectar and pollen residue data. The US EPA has recently received residue study data from several pesticide registrants that can be used to adequately describe the distribution of pesticide residues that occur in pollen and nectar relative to application rate, method of application, and crop. By combining the EU and US EPA variety of plant matrices, especially nectar and pollen databases a statistically refined estimation of RUD values can be calculated. The calculated nectar and pollen RUD values will then inform the BeeREX model with exposure data relevant to the bee risk assessment.
TITLE:
Field Endpoints: Linking Pesticide Field Study Measurement Endpoints to Protection Goals for Pesticide Risk Assessment
AUTHORS:
Jennifer Stafford, Larry Brewer (Compliance Services International); Audrey Bone (Duke University); Steven Levine (Bayer AG – Crop Science Division); Daniel Edwards (BASF Corporation); Alan Jones (FMC Corporation); Spencer Mortensen (BASF Corporation); Richard Brain (Syngenta Crop Protection Inc.); Kevin Henry (NovaSource / Tessenderlo Kerley, Inc.); Mano Basu (CropLife America)
ABSTRACT:
Field studies of pesticide exposure and effects have been conducted for decades. EPA first published guidance for such field studies in 1982, including designs incorporating aquatic organisms, birds and mammals, and aquatic and terrestrial plant species. Further information on semi-field and field testing was issued as recently as 2014, when EPA released guidance for pollinator field studies. These studies present additional opportunities for refinement and addressing uncertainties of a tiered ecological risk assessment paradigm, when needed. However, well-established laboratory-based acute and chronic effect studies that meet specific data quality requirements and which are focused on individuals remain the backbone for FIFRA ecological risk assessment and Endangered Species Act risk assessments. Field effects studies can produce data that are complex, susceptible to confounding factors, and often difficult to interpret; thus limiting their application in some risk assessment scenarios. However, carefully designed and rigorously executed field effects studies can also provide data that are superior to laboratory studies by addressing effects at the population level and above, by examining population dynamics, species diversity, species abundance, recovery, and other relevant higher-tier endpoints. Ideally, a focused field study design can maximize these benefits while minimizing the shortcomings inherent to these study designs. For example, flexibility in study design should facilitate focus on compound-specific, use-specific, target organism-specific, and/or process-specific considerations. Further, simple designs employing straight-forward endpoints to measure and interpret in field studies should be prioritized over more complex, resource-intensive designs that do not add proportional value to the risk assessment. This paper assesses the current status of field study use in pesticide risk assessment, review a number of relevant field study designs, and describe how these attributes can be aligned with assessment endpoints and specific protection goals for both FIFRA and ESA in order to better inform risk assessments.
TITLE:
Weight of Evidence for Threatened and Endangered Species: A Case Study
AUTHORS:
David Campana, Leah Duzy, Ashlea Frank, Jeffrey Giddings (Compliance Services International)
ABSTRACT:
Systematically reviewing multiple lines of information from independent sources to assess if a particular conclusion is supported through a “weight of evidence” framework is a common scientific process used to evaluate studies with conflicting outcomes. Using a weight of evidence framework has been used to evaluate the available evidence of effects of an action or activity for a variety of topics. There has been interest and effort from pesticide registrants, regulators, and the larger scientific community in recent years to refine and institute a common method under the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) due to the variety of different methods used to conduct a weight of evidence. The objective of presentation is to outline and identify lines of evidence that are relevant to a weight of evidence for a pesticide endangered species evaluation under FIFRA. We use a case study to illustrate how the weight of evidence can be used to evaluate the effects of pesticides on species listed under the Endangered Species Act as part of a pesticide registration or registration review. The case study focuses on bifenthrin use and usage in cotton and assumes a risk hypothesis that the use would adversely impact the Cape Fear shiner (Notropis mekistocholas), an endangered fish. The weight of evidence focuses on assembling data to introduce both the proposed action (pesticide registration) and the ESA-listed species under evaluation, as well as consultation and conservation activities that together have been established on the landscape and the status of the species.
SESSION:
When Standardized Regulatory Tests Are Not Enough
TITLE:
Weight of Evidence Assessment to Confirm the Low Bioaccumulation Potential of Bifenthrin As Defined Under Canada’s Toxic Substances Management Policy
AUTHORS:
Dwayne Moore (Instrinsik Ltd); Jeffrey Giddings (Compliance Services International); Jon Arnot (ARC Arnot Research & Consulting); James Armitage (AES Armitage Environmental Sciences, Inc.); Alan Samel (FMC Corporation); Rosa Trevisan (FMC Corporation); Theresa Geil (FMC Corporation)
ABSTRACT:
The purpose of this research was to assess the bioaccumulation potential of the pyrethroid insecticide, bifenthrin, against the bioaccumulation criterion listed in the Canadian Toxic Substances Management Policy (TSMP). The bioaccumulation assessment was carried out using a weight-of-evidence (WoE) approach that considered the quality and results of aquatic laboratory, mesocosm and field studies, refined bioaccumulation modeling, and a comparison of the bioaccumulation potential of bifenthrin to other pyrethroids. The WoE assessment was carried out as prescribed by the OECD Series on Testing and Assessment No. 311 guidance. To be considered bioaccumulative under the TSMP, the bioconcentration factor (BCF) of bioaccumulation factor (BAF) calculated for the compound must exceed 5000 L/kg wet weight (ww). The estimated bioconcentration factors (BCFs) from the most reliable regulatory laboratory bioconcentration studies with fish and bifenthrin ranged from 1030 to 1414 L/kg ww and BAFs from reliable mesocosm and field studies were well below 5000 for fish. Mass balance food web bioaccumulation modeling conducted under different exposure conditions, not calibrated to the measured results of the field study, generated predicted BAFs for fish very close to the field measured values and were well below the TSMP criterion of 5000. Laboratory bioconcentration, modeling and depuration studies with fish were also examined for 5-7 other pyrethroids. As a class, BCFs, whether measured or predicted, were infrequently above 1000 and never exceeded the TSMP criterion of 5000. High-quality studies have demonstrated that pyrethroids, including bifenthrin, are rapidly metabolized and detoxified in organisms, which is the primary reason for their low bioaccumulation potential. The four lines of evidence, including laboratory data, mesocosm and field data, mass balance food web modeling and information from other pyrethroids, all support the conclusion that bifenthrin is not bioaccumulative as defined under the TSMP. Because the confidence in each line of evidence is high and the different approaches corroborate one another, we have high confidence in the conclusion.
