UNITED STATE S ENVIRONMENTAL P R OTECTI O N A GENCY

WAS HIN G T O N D.C

. , 20460

MEMORANDUM PC Code: 101103

DP Code: 415383

December 3, 2013

Subject:

To:

From:

Through: Environmental Fate and Effects Division's Response to Public Comments on Registration Review: Preliminary Problem Formulation for Pymetrozine

Steven Snyderman, Chemical Review Manager

Patricia Parrott, Chief

Risk Management and Implementation Branch III

Pesticide Re-evaluation Division (7508P)

Rochelle Bohaty

, Ph.D.,

## Chemi~ Katherine R. Stebbins

, Biologist

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Environmental Fate and Effects Division (7507P)

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Dana Spatz, Branch**Chief~ ~** 

Environmental Risk Branch III

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## ~~1.1>/'6 Rosanna Louie-Juzwiak, RAPL /1)

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Environmenta l Fate and Effects Divis i on (7507P)**.**

This document contains the Environmental Fate and Effects Division's (EFED's) responses to Sygenta's comments on the Pymetrozine Registration Review Preliminary Problem formulation that

are within the purview ofEFED (e

. g., comments submitted related to the environmental fate, drinking

water exposure and ecological assessments)

. Each comment received is numbered and includes the

text within EPA's assessment for which a comment was received, a summary of the comment

received

, and then EFED's response to the comment.

1

. EPA Preliminary Problem Formulation: "Parent

, CGA-23199

, CGA-359009

, . CGA-23199

were not detected below 0- 6 inch depth" for the bareground plot (pg. 13).

Comment Summary: CGA-294849 was also not detected below the 0-6" depth.

EFED RESPONSE : EFED confirmed that CGA-294849 was also not detected below the 0-6" depth

in the bareground plot [pg. 11 of the Terrestrial Field Dissipation (TFD) Study Data Evaluation (DER) MRIDs 44471703, 44411333, 44411337

, 44411339, 44411332, 44411336, 44411335, and

4464 7904)]. This information will be considered as part of the registration review risk assessment.

2. EPA Preliminary Problem Formulation: "MRID 44647901, 44411334, 44471703, 44647904

, 44411338

, 44647903 (supplemental) Analytical methods were inadequate for detecting CGA

### 1

### 2 249257, storage stability for the CGA-180777, CGA-249257, and CGA-359009 were inadequate” pg. 13.

Comment Summary: An additional amendment to the final report (MRID 45387803) was not

included in this review. This amendment incl udes additional storage stability data for CGA215944, CGA-359009, CGA-249257, CGA-294849, GS-23199, and CGA-180777.

EFED RESPONSE: The amendment to the final report (MRID 45387803) was reviewed. Thisstudy provides additional storage stability data for the CGA-180777, CGA-294849 and GS23199. These data indicate that the aforementioned chemicals were stable during the TFD storage period. However, this amendment does not provi de additional storage stability data for CGA249257 and CGA-359009 nor does it address the problems associated with the analytical methods

for CGA- 249257. This additional information will be considered as part of the registration review risk assessment; however, additional data are still lacking for CGA-249257 and CGA359009.



### 3. EPA Preliminary Problem Formulation: “Parent and CGA-359009 were not detected below 0- 6 inch depth” for the cotton plot (pg. 13).

Comment Summary: CGA-294849 was also not detected below 0-6" depth.

EFED RESPONSE: EFED confirmed that CGA-294849 was also not detected below the 0-6" depth in cotton plot (pg. 12 the TFD DER MRIDs 44471703, 44411333, 44411337, 44411339, 44411332, 44411336, 44411335 , and 44647904)]). This information will be considered as part of the registration review risk assessment.



### 4. EPA Preliminary Problem Formulation: “MRID 44411334 (supplemental) 44647902 & 44647901 Analytical methods were inadequate for detecting CGA-249257, storage stability for the CGA-180777, CGA-249257 and GA-3590 09 were inadequate,” pg. 13.

Comment Summary: Storage stability data for CGA-359009 and CGA-249257 included inMRID 44411334 span 0-353 days. The longest sample holding time was 318 days for CGA359009 with the exception of 3 reanalyzed sa mples. No appreciable losses for CGA-359009 relative to fresh spikes were observed under fr eezer storage conditions. An additional amendment to the final report (MRID 45387801) was not included in this review. This amendment includes additional storage stability data for CGA-2948 49, GS-23199, and CGA-180777. These chemicals exhibited no appreciable losses under freezer storage conditions.

EFED RESPONSE: An additional amendment (MRID 45387803) to the final report (MRID 45387801) was not included in the problem form ulation. This amendment includes additional storage stability data for CGA-294849, GS-23199, and CGA-180777. These data indicate that the aforementioned chemicals were stable during the TFD storage period. However, this amendment does not provide additional storage stability data for CGA-249257 and CGA-359009 nor does it address the problems associated with the analyti cal methods for CGA- 249257. This information will be considered as part of the registration review risk assessment; however, data are still lacking for CGA-249257 and CGA-359009.



### 5. EPA Preliminary Problem Formulation: “No residues were not detected below 0-6 inch depth” for the bareground plot (pg. 14).

### 3 Comment Summary: No residues were detected below the 0-6 inch depth for the bareground plot.

EFED RESPONSE: This typographical error will be corrected and accurately reflected in the registration review risk assessment.



### 6. EPA Preliminary Problem Formulation: “No residues were not detected below 0-6 inch depth,” in the tomato plot (pg. 14).

Comment Summary: No quantifiable residues were detected below the 0-6 inch depth for the tomato plot.

EFED RESPONSE: This typographical correction will be reflected in the registration review

risk assessment.



### 7. EPA Preliminary Problem Formulation: “MRID 44411338, 44647903 (supplemental) analytical methods were inadequate for det ecting CGA-249257, storage stability for the CGA294849 and GS-23199 were inadequate” pg. 14.

Comment Summary: An additional amendment to the final report (MRID 45387802) was not included in the problem formulation. This ame ndment includes additional storage stability data for CGA-294849, GS-23199, and CGA-180777. None of these analytes exhibited appreciable losses under freezer storage conditions; therefore Sy ngenta believes the storage stability data are sufficient to support the terrestrial field dissipation studies.

EFED RESPONSE: The amendment to the final report (MRID 45387802) was reviewed. Thisstudy provides additional storage stability data for the CGA-180777, CGA-294849 and GS23199. These data indicate that the aforementioned chemicals were stable during the TFD storage period. However, this amendment does not provi de additional storage stability data for CGA249257 and CGA-359009 nor does it address the problems associated with the analytical methods

for CGA- 249257. This information will be considered as part of the registration review risk assessment; however, data are still lacking for CGA-249257 and CGA-359009.



### 8. EPA Preliminary Problem Formulation: “Bobwhite quail ( Colinus virginianus ); NOAEC = 100 mg a.i./kg; LOAEC = 300 mg a.i./kg based on number of 14-day old survivors of eggs set; MRID 44024911 (Acceptable)” pg. 22

Comment Summary: Consistent with the original st udy report, no treatment-related effects

were detected in the variables tested and th e NOAEC value should be 300 mg a.i./kg based on statistical analysis of the dataset with the removal of the outlier in the highest treatment group (Cage 64 - assumed to have an infertile male or female, infertility was not treatment related).

EFED RESPONSE: The EFED reviewer agrees that one replicate in the highest treatment level (cage 64) is an outlier (as a result of an infertile male or female) and this replicate was removed from the dataset in a second analysis within the DER review. After the replicate pen was removed from the analysis, the percentage of 14-day old survivors of eggs set at the highest treatment level (300 ppm) was still significantly less than the control (Dunnett’s, α = 0.05) and the reviewer believes that this response is a treatment related effect. Hence, the resulting NOAEC is 100 mg a.i./kg.

### 4 9. EPA Preliminary Problem Formulation: “Storage stability for the CGA-180777, CGA249257, and CGA-359009 were inadequate. Becau se CGA-359009 is one of the identified residues of concern, submission of storag e stability studies are needed” (pg. 29).

Comment Summary: Storage stability data for CGA-359009 in soils from California, Georgia,

and New York are included in the terrestrial fi eld dissipation studies and related amendments: MRID 44411338, 44471703, 45387803, and 44411334. Although there is an apparent loss of recovery in the Georgia soil at the last time point, this is not consistent with studies from California and New York which cover longer time spans and show no appreciable losses. Existing data demonstrate CGA-359009 is stable und er freezer storage conditions and sufficiently support the terrestrial field dissipation studies.

EFED RESPONSE: Storage stability studies for CGA-359009 in California and New York soils suggest stability in these two soils under the storag e conditions; however, data are lacking for the Georgia soil or a rationale on why CGA-359009 was stable in California and New York soils, but not stable in the Georgia soil. The storage stab ility of CGA-359009 in the Georgia soil remains an uncertainty.



### 10. EPA Preliminary Problem Formulation: “Results are not consistent between hydrolysis studies (MRIDs 44024964 and 44024963) for pH 5, with half-lives ranging from 12 to 28 days. Because hydrolysis appears to be an important route of dissipation in acidic environments, additional abiotic hydrolysis data for pH 5 are needed.” pg. 28.

Comment Summary: Results are not consistent between studies at pH=5 (at 25 °C). Half-lives range between 5 d and 12 d. At pH=7 and pH =9 (at 25 °C) the compound is relatively stable.

EFED RESPONSE: The three hydrolysis studies (MRIDs 44024962, 44024963, and 44024964) submitted to EPA for pymetrozine were reexamin ed. The inconsistencies between hydrolysis half-life values (ranges from 16.9 to 26.8 d using non-linear single first order kinetic model) for pH 5 were confirmed. Reported a nd recalculated half-life values are shown in the table below for pH 5. In the absence of new data, the hydrolysis half-life of pymetrozine at pH at 5 will be assumed to be 28 days.

Source

Classification pH 5

DT 50 Value 1 Comments

MRID 44024962 (triazine ring labeled) supplemental 12.1 days Value reported in DER and preliminary problem formulation; values was calculated using linear regression of log transformed concentration data for parent 22.0 days Value calculated using non-linear single first order model 2
14.9 Value calculated using DFOP model 2

MRID 44024963

Supplemental (triazine ring-labeled) 28.4 days Value reported in DER and preliminary problem formulation; values was calculated using linear regression of log transformed concentration data for parent 26.7 days Value calculated using non-linear single first order model 2

MRID 44024964 Draft DER; Supplemental (pyridine ring-labeled) 14.4 days Value reported in DER and preliminary problem formulation; values was calculated using linear regression of log transformed concentration data for parent 16.9 days Value calculated using non-linear single first order model 2
11.6 days Value calculated using IORE model 2

1. DER noted that hydrolysis of pymetrozine was biphasic; however, due to the discrepancy in the half-life values the quality of the data are questionable.

2. DT50 were calculated using nonlinear regression and single first-order (SFO), double first- order

### 5 in parallel (DFOP), or indeterminate- order equa tion (IORE). The equations can be found in the document, Standard Operating Procedure for Using the NAFTA Guidance to Calculate Representative Half-life Values and Characterize Pesticide Degradation, Agency December 21,

2012.



### 11. EPA Preliminary Problem Formulation: In the aqueous photolysis experiment “A major degradate (up to 28.9% AR) was not identified. Id entification of this transformation product is needed to rule out the potential that it is a residue of toxicological concern. In absence of the data, this residue may be considered as part of a TTR approach in modeling to account for this uncertainty” (pg. 28).

Comment Summary: “ID via HPLC between 92 and 97% AR ((pyridinyl-label); 21-24% CGA215944 and 71-73% CGA-300407 and 98% ((triazinyl-label); 23-24% CGA-215944, 65-68% CGA-2155525) and 23% CGA249257)...[critical endpoints listed]”

EFED RESPONSE: The comment received is unclear. EFED interpreted the comment as suggesting that the unidentified residues could be either CGA-215944 or CGA-215525; however, the major (28.9%) transformation product not identified in the study cannot be identified by EFED as the necessary data were not supplied to support this comment. Additional data that indentifies this unidentified major (28.9%) tran sformation product would reduce uncertainty. In absence of the data, this residue may be consider ed as part of a TTR approach in modeling to account for this uncertainty. If this comment was misinterpreted, the commenter should clarify the comment and submit any supporting data that has not previously been reviewed by the Agency.



### 12. EPA Preliminary Problem Formulation: Soil Photolysis: A large amount of unextracted residues (>75%) was observed in the irradiated samples compared to the dark control (<20%) at study termination.” pg. 28.

Comment Summary: MRID 45208702 employed four extraction techniques and removal of bound residues was improved; more components identified, however, approximately 30% of applied radioactivity (AR) not identified (pyrid inyl-label) and approximately 50% of AR not identified (triazine-label). Non single first order kinetics was observed; however, in all previous studies first order kinetics was observed. All residues higher than 10% were identified.

EFED RESPONSE: MRID 45208702 will be considered as part of the registration review process; however, the extraction methods [extrac tion 1) 80:20 acetonitrile:water and extraction 2) 3:1 acetonitrile:water] employed in this study prio r to fractionation are not considered exhaustive. Residues extracted using extraction methods 1 and 2 were identified at concentrations greater than 10%. Nevertheless, up to 11% and 13% of the applied radioactivity was reported as “residue” and not identified in the cited study (MRID 45208702), for the control and irritated samples. Furthermore, a large amount (up to an additional 30%) of radioactivity was isolated as part of extraction 3 (fractionation) and not identifie d. No data are available to determine if the isolated radioactivity was associated with residues that could have been extracted using a solvent system other than the acetonitrile and water system s mentioned above (extractions 1 and 2) or if the residues are truly bound residues). Additiona l solvent systems should have been explored prior to fractionation (extractions 3 and 4). While soil photolysis does not appear to result in the formation of unique phototransfo rmation products, additional information would reduce the uncertainty associated with the unextracted/uniden tified residues in both so il photolysis studies.

### 6 13. EPA Preliminary Problem Formulation: “Current guidelines recommend aerobic soil

metabolism data be submitted for a total of five different soils. In the absence of these data the

calculated aerobic soil metabolism half-life value will be multiplied by 3 to generate model input values. This adjustment factor is applied to account for the uncertainty associated with the variation in transformation in different soil systems.” pg. 28.

Comment Summary: Several additional aerobic soil metabolism half-life values as well as

maximum observed concentrations of a numbe r of transformation products were cited.

EFED RESPONSE: The half-life values and the maximum observed concentrations provided cannot be verified by EFED as the necessary data were not supplied to support this comment received on the preliminary problem formation. The cited study should be submitted for the Agency to review.

Any additional data to address this issue will be c onsidered as part of the registration review risk

assessment. In absence of these data , the calculated aerobic soil metabolism half-life value will be multiplied by 3 to generate model input values. This adjustment factor is applied to account for the uncertainty associated with the variation in transformation in different soil systems.



### 14. EPA Preliminary Problem Formulation: Aerobic aquatic metabolism “data have not been

submitted to the EPA. In absence of these data th e calculated aerobic soil metabolism half-life input values will be multiplied by 2 (6 times the aerobic soil half-life value) to generate model input value for aerobic aquatic metabolism. This ad justment factor is applied to account for the uncertainty associated with the difference between aerobic soil and aerobic aquatic metabolism.” pg. 29.

Comment Summary: Aerobic aquatic metabolism half-life values as well as maximum observed

concentrations of a number of tran sformation products were cited.

EFED RESPONSE: The half-life values and the maximum observed concentrations cannot be verified by EFED as the necessary data were not supplied to support this comment received on the preliminary problem formation. The cite d study should be submitted for the Agency to

review.

Any additional data to address this issue will be c onsidered as part of the registration review risk

assessment. In absence of these data the calculated aerobic soil metabolism half-life input values will be multiplied by 2 (6 times the aerobic soil half-life value) to generate model input value for aerobic aquatic metabolism. This adjustment fact or is applied to account for the uncertainty associated with the difference between aerobic soil and aerobic aquatic metabolism



### 15. EPA Preliminary Problem Formulation: “Anaerobic Aquatic Metabolism: Current guidelines recommend anaerobic aquatic metabolism data be s ubmitted for a total of two different sediment: water systems.” pg. 29.

Comment Summary: Anaerobic aquatic metabolism half-life values as well as maximum

observed concentrations of a number of transf ormation products were cited for one sediment

water system.

EFED RESPONSE: The half-life values and the maximum observed concentrations cannot be verified by EFED as the necessary data were not supplied to support this comment received on

### 7 the preliminary problem formation. The cited study should be submitted for the Agency to

review.

Any additional data to address this issue will be c onsidered as part of the registration review risk

assessment.



### 16. EPA Preliminary Problem Formulation: “Consistent with the Agency's responsibility under the Endangered Species Endangered Species Act (E SA), the Agency will evaluate risks to federally listed threatened and/or endangered species (“listed species") from registered uses of pesticides in registration review. These asse ssments will be conducted in accordance with standard EPA procedures and good scientific judgment.

Comment Summary: Syngenta has submitted a document to the registration review docket summarizing the types of refinements that should be considered for an endangered species assessment (Risk Assessment Considerations Concerning the Potential/Impacts of Pesticides on Endangered Species, Syngenta Report Number TK0181948).

EFED RESPONSE: EPA will considered the submitted doc ument and plans to address concerns raised for assessing the risks of pesticides to lis ted species based on the recommendations of the April 2013 National Academy of Sciences (NAS) re port. EPA will address concerns specific to pymetrozine in connection with the development of its registration review decision document.

The NAS report, available at http://www.na p.edu/catalog.php?record_id=18344, outlines recommendations on specific scientific and techni cal issues related to the development of pesticide risk assessments that are compliant with the Endangered Species Act and the Federal Insecticide, Fungicide, and Rodenticide Act. In November, the EPA, along with the U.S. Fish & Wildlife Service (USFWS), the National Marine Fi sheries Service (NMFS) (collectively, the Services), and the U.S. Department of Agriculture (USDA), released a summary of their joint Interim Approaches for assessing risks to listed species from pesticides. The Interim Approaches were developed jointly by the Agencies in r esponse to the NAS’ recommendations and reflect a common approach to risk assessment shared by the Agencies as a way of addressing scientific differences between EPA and the Services. The jo int Interim Approaches were released prior to the stakeholder workshop held on November 15, 2013. EPA is presenting the joint Interim Approaches at the December 2013 PPDC and SFIREG meetings, allowing additional opportunities for stakeholders to comment on the Interim Approaches. The Agencies will consider public comments on the Interim Approaches prior to implementing them. The Agencies intend to jointly implement these approaches as part of a phased iterative process. EPA will refine its listed species risk assessments based on these interim approaches. The details of the joint Interim Approaches are contained in the white paper “Interim Approaches for NationalLevel Pesticide Endangered Species Act Assess ments Based on the Recommendations of the National Academy of Sciences April 2013 Report, ” dated November 1, 2013, available at http://www.epa.gov/espp/2013/nas.html.