OFFICE OF CHEMICAL SAFETY AND POLLUTION PREVENTION UNITED STATES ENVIRONMENTAL PROTECTION AGENCY WASHINGTON, D.C. 20460



### RE: Meeting between Dow AgroSciences (DAS) and EPA to Discuss DAS’ Proposal for Developing a Chlorpyrifos Higher Tier Ecological Risk Assessment

List of Documents

1. Meeting Summary Page 1 2. Meeting Sign in Sheet Page 2 3. DAS Talking Points for the Meeting Page 3

Meeting Summary

On Monday, December 12, 2011, EPA’s Office of Pesticide Programs met with Dow AgroSciences (DAS) to discuss their proposal for developing a chlorpyrifos higher tier ecological risk assessment. DAS is planning to convene its own panel to generate a higher

-tier ecological risk assessment in the next 1

-2 years and wanted to discuss this proposal with the Agency. Areas discussed included fate and transport of chlorpyrifos and the chlorpyrifos oxon, endangered species, modeling of exposures in aquatic and terrestrial systems, and effects in aquatic and terrestrial systems. DAS will also be submitting to the Agency a bibliography of published papers since 2000 dealing with chlorpyrifos.

### Name

# J~L Wo Dow AgroSciences and EPA Chlorpyrifos EcoriskMeeting December 12,2011

Affiliation Phone Number E-mail



# keu5s PA:Afu;Vl- 

# GV'..41 E;Fc;p 

## f<J3**-?oS'~f?fJ/o** PAtvc,bVt,

## MtW5~**~Vl4-:.** '-- ·/

## \(o.so.v~no.**~\e:Juz.wa~** e\/A (

## E~et::> ?o3

## ~ 3o5

- 003 

### 7

## lOU.l~juzwco.lt..

## foSCl.V\t\<A@~.

## Talking points for the meeting of Dow AgroSciences Chlorpyrifos Panel with EPA on December 12, 2011

Participants in the Meeting Prof. John P. Giesy, Chair, DAS Chlorpyrifos Panel Prof. Keith Solomon, Co-Chair, DAS Chlorpyrifos Panel Dr. Nick Poletika, Science Leader, DAS Dr. Darin Lickfeldt, Regulatory Manager, DAS



## 1 Purpose ofthe meeting
Dow AgroSciences will be using our own panel over the next 1-2 years to generate a higher-tier risk assessment much like we did for the Human Health risk assessment submitted in October 2011. We want to be open and transparent throughout this process to make sure the areas of greatest concern with regards to Chlorpyrifos are addressed by our analysis. Therefore, we need a better understanding of areas of greatest concern or areas that need better definition. We hope to get a better understanding of where data gaps exist from EFEDs perspective. What additional data/analysis' would be useful to have 1-2 years from now?

Members ofthe panel include:

Prof. John P. Giesy, Ph.D., FRSC, Prof. 

### & Canada Research Chair in Environmental Toxicology University of Saskatchewan

Prof. Keith R. Solomon, Ph.D., Emeritus Prof. University of Guelph

Dr. Jeff Giddings, Ph.D. Compliance Services, Inc.

Dr. Dwayne Moore, Ph.D. lntrinsik Environmental Sciences, Inc

Other expert(s) will be added as needed and as issues are identified at this meeting and when the data are assembled.

Page 1 of4

## 2 Questions ofclarification from the problem formulation

2.1 Mode(s) ofaction
1. How will EPA incorporate metabolic activation of chlorpyrifos into the conceptual model for exposure and/or effects? 2. Is EPA considering synergism ofchlorpyrifos in its conceptual model ofeffects? 3. How will EPA integrate other potential effects such as those modulated by the endocrine system into the conceptual model ofeffects?



### 2.2 Fate and transport of chlorpyrifos
1. How will EPA consider movement to and accumulation in distant locations in the conceptual model for exposures?


### 2.3 Fate, transport, and toxicity of chlorpyrifos oxon and other products of degradation
1. How is EPA planning to consider fate of chlorpyrifos oxon in environmental media? 2. How will exposures to the oxon be incorporated into the conceptual model of exposures? 3. How does the EPA plan to consider degradates such as trichlorophenol?



### 2.4 Bioconcentration and bioaccumulation
1 . Whatwill the approach be for aquatic systems? 2. Whatwill the approach be for terrestrial systems?


### 2.5 Modeling ofexposures in aquatic and terrestrial systems
1. Will EPA model both maximum and typical application rates and intervals? What

use patterns are of particular interest to EPA in their assessment? 2. Is EPA planning to refine the conceptual model(s) for direct and indirect exposures in aquatic systems? 3. Is EPA planning to refine the conceptual model for exposures of terrestrial organisms? 4. Is EPA planning on conducting food web modeling for assessing risk to avian predators, such as through relay toxicity? 5. How will EPA refine the conceptual model for exposure of birds to the oxon? 6. Will EPA consider using chlorpyrifos-specific nomograms instead ofthe standard Kenaga nomograms? 7. Will EPA consider using more advanced methods than the current LD50s/ff method for characterizing exposures to granularformulations in birds? 8. For the flowable formulation, will EPA conduct higher tier assessments for birds and mammals (i.e., beyond standard T-REX analysis)? 9. Will herps, such as frogs and salamanders be included in the terrestrial assessment? 10.Will EPA model the concentrations of chlorpyrifos in flowing water, estuaries, and otherwater bodies where exposure will differ from the standard pond scenario? 11. How is EPA planning to model the exposure ofsediment-dwelling organisms?

Page 2 of4 t

### 2.6 Effects in aquatic systems
1. Is EPA planning to refine the conceptual model(s) for direct and indirect effects in aquatic systems? 2. How will data from microcosms, mesocosms and field studies be incorporated into the characterization ofeffects? 3. How will EPA assess risk to aquatic vascular plants if toxicity data are unavailable? 4. How will bioavailability of chlorpyrifos in different kinds of sediment be taken into account in assessing effects on benthic organisms? 5. When results of toxicity tests are available from multiple studies on the same species, possibly including both GLP and non-GLP studies, what criteria will EPA

use in selecting endpoints for the risk assessment (e.g., lowest reported value, geometric mean, ecological relevance, reliability)? 6. Is EPA planning to use population models to estimate risk to sensitive aquatic species?



### 2.7 Effects in terrestrial systems
1. Will EPA be refining the conceptual model(s) for direct and effects? 2. How will EPA incorporate incident data and field studies into the conceptual model for effects? 3. When results oftoxicity test are available from both GLP and non-GLP studies on the same species and endpoint, will EPA give preference to the GLP study results? 4. Can EPA provide insight into how the pollinators portion of the assessment will be conducted? 5. Are effects on plants a concern and ifso how will they be evaluated?


### 2.8 Endangered species
1. Will EPA be issuing guidance on the conduct of National Endangered Species Assessments in the near future so that we can better understand their planned approach? 2. How will information provided by registrants about the location, biology, and ecology ofT&E species be incorporated into EPA's ES assessment? 3. To what level of resolution will spatial modeling ofexposures be considered? 4. How will habitat preference be considered (e.g., if the T&E species only found at higher elevations and thus not susceptible to runoff exposure)? 5. How will sensitivity be considered (e.g., T&E plants likely not be at risk for chlorpyrifos even in close proximity)? Said another way, will risk to T&E species be estimated using toxicity data for closely related surrogate species, or will only the most sensitive species in each major taxonomic group (e.g., fish, aquatic invertebrates, birds, mammals) be used? 6. Will indirect effects be assessed in the context of the specific food and habitat requirements of individual T&E species? 7. Does EPA intend to work with registrants to develop mitigations to reduce risk to T&E species before requesting consultation with the Services?

Page 3 of4

### 2.9 Concentrations in aquatic systems
1. How will EPA be updating the data on concentrations in aquatic systems from the situation in 2007? 2. Does the EPA plan to use data on concentrations measured in targeted monitoring programs from states such as CA and the Pacific Northwest? 3. If concentrations measured in targeted monitoring programs indicate that the standard aquatic exposure model overestimates chlorpyrifos concentrations, will the monitoring data be used to support more realistic assumptions in the model?



## 3 Published papers for 2000-present

1. The panel will describe for EPA the database of papers that has been developed. The panel is willing to share all of this information and our summaries of the information contained in the papers with EPA.

Page 4 of 4