PWG-EPA Meeting  -  Discussion of Pollinator Framework
Video Conference  -  Microsoft Teams
28 October 2020

Participants:
Company
Name
EPA Attendees

Pesticide Re-evaluation Division
Cathryn Britton, Branch Chief, Branch V 

Moana Appleyard, Senior Regulatory Advisor, Branch II 

Kevin Costello, Branch Chief, Branch II 

Melanie Biscoe, Senior Regulatory Advisor, Branch V

Khue Nguyen, Team Leader, Branch V

Katherine Stebbins, Pollinator Team Rep, Branch III

Samantha Thomas, Chemical Review Manager, Branch V


Environmental Fate and Effects Division
Keith Sappington, Senior Advisor, Branch V

Greg Orrick, Risk Assessment Process Leader, Branch I

Justin Housenger, Branch Chief, Branch V

Tom Steeger, Senior Advisor, Branch IV


PWG Attendees

FMC
Jill Holihan, Tim Formella, Bibek Sharma
Valent/MGK
Julie Schlekau, Steve Ditto
BASF
Dave Haughey
Bayer
Jan Brill, Ona Maune
Phasera
Paul Hendley
Waterborne
Jennifer Collins

Minutes:

 Introduction by C. Britton
 Success in regulating pyrethroids as a class in the aquatic risk assessment
 Interest in applying a similar approach for pollinator risk assessment
 EPA memo addressing bridging approaches will be released in the near future
 Presentation by P. Hendley (refer to meeting slides - - Pyrethroid Pollinator Study Approach Proposal 201028.pptx)
 As effective insecticides, pyrethroids typically fail Tier I screening-level risk assessment for pollinators
 Due to similar mode of action, environmental fate properties and behavior, PWG proposes a bridging framework for efficient use of resources and streamlined data generation for the pollinator risk assessment process.
 Investigation of existing pyrethroid study data
 Not all studies have been submitted to EPA at this time
 Tier I studies: 56 total studies 
 Endpoints were normalized based on application rates to express a relative potency for direct comparison purposes
 Pyrethroids have similar toxicity to pollinators when normalized for application rate and PWG believes that additional Tier 1 data generation beyond the available studies will not likely provide new information relevant to the risk assessment process. 
 Two questions from K. Sappington: (1) confirmation of the graph and units (clarified dual axis presentation); (2) asked about larval chronic units (cumulative dose, not adjusted per day).  K. Sappington also expressed importance of the Tier 1 data set for understanding chronic effects, endangered species etc.
 Semi-field and field studies: 67 studies
 Most are EU studies (typically lower application rates than US rates)
 Extremely wide range of study objectives, designs, and measured endpoints
 Non-systemic nature of pyrethroids is reflected in residues (peak at Day 1 with sharp declines after)
 Only applications during bloom generated impacts, which were rate-dependent and transient (only individual effects, no colony level effects)
 Reduced effects in field studies relative to tunnel studies
 All pyrethroids exhibited repellency (reduced flight intensity and reduction in foraging) even at the lower EU rates.
 Question from K. Sappington:  Consideration of exposure from spray drift which would apply to crops where the compound is NOT being applied during bloom (or to non-blooming crops)
 P. Hendley response : We will need to consider spray drift, and the lower use rate data from EU may be able to help us do so.
 RT25 data:  
 Seven studies covering a wide range of older protocols (1977  -  2019)
 PWG Proposal:
 RT25 study currently lacks a standard protocol  -  thus results can be highly variable 
 If a reliable and comparable RT25 protocol can be developed, PWG proposes to use this test as a mechanism to select representative pyrethroid products for higher tier testing: no further higher tier studies
 RT25 >6 hours: RT25 data used to select representative pyrethroid products (example, one mid and one long RT25 product) for higher Tier studies
 Since this approach depends on a reliable test protocol for pyrethroids, PWG proposes to support PRTF by determining applicability for pyrethroids by doing testing in 2021.
 Then in 2022, if consistent and reliable protocol can be generated, PWG would propose performing RT25 studies on all PWG pyrethroid products with labels for application at bloom to bee-attractive crops.
 PWG considers this proposal to be pragmatic and efficient due to:
 Long history of use with low incidents, now with additional label protections
 Non-systemic nature of pyrethroids
 Repellency to pollinators and other taxa
 Allows targeted yet conservative data generation for efficient use of resources
 Discussion
 Questions on Slides (K. Sappington)
 From Tier I data summary, not seeing a big difference between acute and chronic studies.  They have seen one set of data he would like to take a look at the acute-to-chronic ratios Using the unadjusted data. For fast-acting mode of action, we should expect to see early toxicity effects in the chronic exposure studies.
 Expect to see a lower acute-to-chronic ratio?
 Action Item:  J Collins and P. Hendley will go back to original data and provide the acute-to-chronic ratios.
 Larval chronic values are quite low  -  are these cumulative or normalized on a per-day basis?
 Values presented are cumulative (not per day)
 General Feedback on Proposal
 Tier I data generation 
 Need to further discuss the need for additional data generation for Tier I studies
 Full characterization of acute and chronic toxicity is useful for analysis of patterns
 They are still concerned about chronic effects
 Would like to see it taken through to BeeRex RQ
 Also desirable for endangered species assessment
 Use of RT25 data is highly dependent on protocol development and what that reflects in the field -  -  from a combination of K. Sappington and T. Steeger.
 
 Exposure may be impacted by plant physiology
 Accessibility of leaves, pollen and nectar to spray and post-spray absorption characteristics of leaves etc. may influence bee exposure
 RT25 might not give the full picture of various plant matrices -  -  i.e. EPA questioning the relevance of alfalfa
 PWG Clarification:  RT25 would be used as a means for selecting surrogates and grouping pyrethroids, and the field or semi-field study will take into account the plant-specific matrices.
 T. Steeger raised a concern about timeframe since the proposal relies upon the RT25 protocol.
 Quoted that they saw RQs that varied by up to a 100 fold 
 PRTF is looking at standardization of cage size and plant cutting  -  variability of weathering will also need to be considered and thus a final agreed protocol may be several years out.
 PWG answer : PWG proposes to conduct tests in 2021 to help move the standardized protocol along in order to determine if the protocol works adequately for pyrethroids  as soon as possible.  EPA is welcome to conduct a protocol review to approve the testing we are proposing.
 PWG comment: In 2022 we expect to have data with reduced uncertainty- especially because we will be having studies run with the same protocol under relatively similar conditions.  
 PWG comment: Delays for improving testing methods are often the case for moving regulatory science forward.
 Tier I Testing and Acute Pollinator Strategy (C. Britton)
 Typically EPA would first focus on Tier I studies before we move along to the need for field and semi-field studies
 We need to remember that we are talking about data generation for use in a regulatory strategy that will be several years down the road (maybe five to seven year)
 Acute policy is out there, but our understanding of pollinator risk may change by the time we are trying to use these data
 EPA is looking for the best possible data that can be generated today to help inform those future decisions.
 RT25 and consideration of residue data (K. Sappington)
 EPA will need to consider the RT25 concept further 
 RT25 studies do not reflect consumption and consists of an acute dermal exposure
 He personally considers the biggest area of refinement for pyrethroids will be on the residue studies. 
 He hypothesized that residue profiles are likely to show a very steep decline, so there may be more value in considering residue studies; may eliminate oral risk
 PWG Action Item: We can go back to look to find one or two more recent studies that have sufficient data to estimate residue profiles in the higher tier studies from the data compilation
 Jill stated that PWG can provide rationale that the selection of conservative and worst-case scenarios covers us for other scenarios.
 B. Sharma: Actual residue values would provide utility but with the numbers and combinations of uses and geographies, the resource involved is very extensive and so we would be looking for an approach to streamline the selection of residue data generation.
 K. Sappington: Significant opportunities to bridge with residue data.  May indicate that there is no risk for oral toxicity.  Would be interested in residue studies from the tunnel and field studies.  Hypothesizes that the measured residues would be an order of magnitude lower than the expected residues using the EPA models.  Rapid decline after D0/D1
 B. Sharma: Tunnel studies are done on worst-case crops
 Tier I data generation 
 PWG commented that If we just move forward with generating additional data  it may result expending significant effort that will not move us forward in the risk assessment process
                        
 Tim Formella then raised the possibility that DCIs will be issued and other pyrethroid registrants may start generating data
 C. Britton: Do we engage and share data with other non-PWG companies? EPA has interest in reducing the overall burden and testing.  
 EPA is starting the DCI process now  -  but internal logistics mean the publication may be  months away
 Other comments:
 We may have difference in how we view the importance of the Tier I data
 C. Britton reiterated desire to minimize unnecessary studies. EPA believes that residue data will be useful; PWG is not convinced and the potential costs from large numbers of studies would be excessive
 The point about the non-systemic nature of pyrethroids seems to be accepted by EPA 
 K. Sappington said that he thought we were aligned when thinking about exposure: non-systemic, short-lived from an oral perspective
 Continue to have dialog on the process beyond the DCI, as occurred for the aquatic risk assessment
 Bridging concept for the generation of data
 Consider this meeting an initial conversation on approach
 Continue meetings to discuss and agree upon a general approach for a conceptual framework.
 EPA would appreciate seeing PWG's notes
