Document ID: EPA-HQ-OPP-2012-0303-0006
Agency: epa
Document Type: Supporting & Related Material
Title: 
Posted Date: 2013-07-03T04:00Z

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
                         WASHINGTON, D.C. 20460      

                                                    	OFFICE OF CHEMICAL SAFETY 
                                                       AND POLLUTION PREVENTION
	

MEMORANDUM

Date: APR-19-2013    

SUBJECT:	Ethalfluralin:  Petition for the Establishment of Tolerances on Rapeseed subgroup 20A and Sunflower Subgroup 20B; Request for Registration of Sonalan[(R)] 10G (EPA Reg No. 62719-184) and Sonalan[(R)] HFP (EPA Reg No. 62719-188) on Rapeseed subgroup 20A and Sunflower Subgroup 20B.

 
PC Code:  113101
DP Barcode:   D401523
Decision No.: 462704
Registration No.: 62719-184 & 62719-188
Petition No.: 2E8007
Regulatory Action: Section 3 Registration 
Risk Assessment Type: Single Chemical/Aggregate
Case No.: None
TXR No.: None
CAS No.: 5523-68-6
MRID No.: None
40 CFR: 180.416

FROM:	Mohsen Sahafeyan, Chemist/Risk Assessor
		Yung G. Yang, Toxicologist
		Risk Assessment Branch VI
		Health Effects Division (7509P)

THROUGH:	Felecia Fort, Branch Chief
		Risk Assessment Branch VI
		Health Effects Division (7509P)
		
TO:	Laura Nollen and Barbara Madden, Minor Use Team
      Risk Integration, Minor Use, and Emergency Response Branch
		Registration Division (7505P)
		

This document provides the Health Effects Division (HED) human health assessment for the proposed establishment of tolerances and registration of new uses of the herbicides ethalfluralin on Rapeseed subgroup 20A and Sunflower Subgroup 20B.

Introduction

Ethalfluralin [N-ethyl-N-(2-methyl-2-propenyl)-2,6-dinitro-4-(trifluoromethyl)-benzenamine] is a selective preemergence herbicide registered for use on a variety of food and feed crops. The Interregional Research Project #4 (IR-4) has requested conversion of existing sunflower and canola/rapeseed tolerances to Rapeseed subgroup 20A and Sunflower subgroup 20B for  Sonalan[(R)] 10G (EPA Reg No. 62719-184) and Sonalan[(R)] HFP (EPA Reg No. 62719-188) with concurrent removal of tolerances for ethalfluralin in or on  rapeseed and sunflower.  Sonalan[(R)] 10G is a granular formulation containing 10% ethalfluralin and Sonalan[(R)] HFP is an emulsifiable concentrate formulation containing 3 lb/gal ethalfluralin.  Both formulations are currently registered for preemergence control of certain annual grasses and broadleaf weeds in crambe, dry beans, dry peas, peanuts, rapeseed, safflower, soybeans, and sunflower.  The petitioner, IR-4, is proposing the following tolerances on the food commodities as shown below.
            
Commodity
Proposed Tolerance (ppm)
Rapeseed subgroup 20A
0.05 
Sunflower subgroup 20B
0.05

Proposed Use

The proposed use pattern for all Rapeseed subgroup 20A and Sunflower subgroup 20B is similar to the existing registered use for canola/rapeseed and sunflower seed.  The current total maximum use rate for Sonalan HFP formulation (3 lb ai/gal) on rapeseed is 2 (1/2) pt/acre (0.94 lb ai/A), on sunflower is 4 (1/2) pt/acre (1.7 lb ai/A) and on safflower is 3 pt/acre (1.1 lb ai/A).  The current total maximum use rate for Sonalan 10G formulation on rapeseed is 9.5 lb ai/A, on sunflower is 17.0 lb ai/A, and on safflower is 11.5 lb ai/A.  Grazing or foraging crops grown in treated soil is restricted.

Toxicity Data and Endpoint Selection
      
The last assessment of the toxicity database for ethalfluralin was included in the most recent comprehensive risk assessment (Ethalfluralin:  Human Health Risk Assessment for (IR-4) Proposed Uses on Dill and Potato, J. R. Tomerlin, 11/2/07.  However, 40 CFR Part 158 was modified in 2007 to include the requirement for a neurotoxicity screening battery and an immunotoxicity study.  In 2012, the Hazard and Science Policy Council (HASPOC) determined that the acute and subchronic neurotoxicity studies as well as a subchronic inhalation toxicity study are not needed for the registered uses of ethalfluralin based on a weight-of-evidence approach considering all the available hazard and exposure information (Ethalfluralin:  Summary of Hazard and Science Policy Council (HASPOC) Meeting of December 6, 2012:  Recommendations on the need for inhalation and neurotoxicity battery (acute and subchronic) studies, Kristin Rury, Feb. 2013, TXR number 0056533).  However, the immunotoxicity study remains a data requirement at this time.  Although an immunotoxicity study has not been received by the Agency, there is relatively little concern as there are no indications of immunotoxicity in the toxicology database; it does not appear that ethalfluralin directly targets the immune system.  Additionally, ethalfluralin does not belong to a class of chemicals (e.g., the organotins, heavy metals, halogenated aromatic hydrocarbons) that would be expected to be immunotoxic.  Furthermore, the Agency does not believe that conducting an immunotoxicity study will result in a lower point of departure (POD) than that currently used for overall risk assessment; therefore, a database uncertainty factor (UFDB) is not needed to account for the lack of the study.  The selected Point of Departures (PODs) and toxicological endpoints and profile from the most recent human health risk assessment do not require modification.  
	
The toxicology database concerning infants and children is considered to be complete with the exception of an immunotoxicity study.  Submitted studies included developmental rat and rabbit, and 2-generation reproduction in rats.  HED has fully evaluated the toxicity database of ethalfluralin with respect to the potential for special sensitivity of infants and children, and concludes that there is low concern for pre- and postnatal susceptibility for infants and children.  The FQPA safety factor has been reduced to 1X because (1) the toxicity database is adequate to characterize potential pre- and postnatal risk for infants and children; (2) no reproductive or developmental effects were observed in rats; and (3) although there were slight developmental effects observed (skeletal malformations) in rabbits (fetuses), they were seen in the presence of maternal toxicity.  Additionally, the dose chosen for acute dietary risk assessment is protective of the slight developmental effects observed in the rabbit developmental toxicity studies.  

Residue Data

No residue data were submitted with this petition.  Rapeseed (canola varieties) and sunflower seed are representative commodities for subgroup 20A and 20B respectively for which there are adequate residue data.  Since the proposed use rates for all commodities in crop subgroup 20A and 20B are similar to those of rapeseed and sunflower seed, no further residue data are required.  Residues in the field trials for canola and sunflower seed were non-detectable.  

Aggregate and Occupational Risks

The reported dietary risk estimates from exposure to food and water from the 2007 risk assessment was <1% of the population adjusted doses (PADs) for both acute and chronic exposures.  The cancer risk estimate was 2 X 10[-6].  The action associated with this petition, i.e., expansion of registered crops from representative crops to crop subgroups 20A and 20B, is not expected to result in acute and chronic dietary exposures (food + water) above 1% of the acute and chronic PADs that were reported in the 2007 assessment.  The change in cancer risk estimate from 2007 risk assessment is also expected to be minimal because the increase in consumption from the additional commodities in crop subgroup 20A and 20B and change in ethalfluralin residue levels in drinking water are expected to be minimal.  There are also no livestock feed items for the commodities in the crop subgroups 20A and 20B and therefore, there is no concern for exposure from livestock.

There are currently tolerances on representative crops of crop subgroups 20A and 20B.  These registered crops, rapeseed seed and sunflower seed, in addition to registered safflower seed are by far the most consumed commodities in crop subgroups 20A and 20B.  Other commodities in crop subgroup 20A and 20B have low consumptions and are not expected to contribute any significant amount to food exposure. 

The major contributor to ethalfluralin dietary exposure is drinking water; the exposure estimate for the cancer assessment was based on monitoring data.  HED has reviewed the most recent water monitoring data to ensure there have not been significant changes from the 2007 assessment.  Data from USDA's Pesticide Data Program (PDP) and US Geological Survey, National Water-Quality Assessment Program (USGS/NAWQA) still show that there have been no detectable or very limited detectable residues of ethalfluralin in sampled drinking water and surface/ground water.  PDP sampled 3515 samples of drinking water between 2006 and 2011 and there were not detects at a limit of detection (LOD) between 30 and 400 parts per trillion (ppt).  Likewise, there has been a very low detection frequency (0.8%) of ethalfluralin in the USGS/NAWQA monitoring data in the last search by The Environmental Fate and Effects Division, EFED (EFED Registration Review Problem Formulation for Ethalfluralin, M. Barratt and J. Housenger, D382172, 03/14/11).  A new search also showed that from 2006 until the last sampling year, 2008, there was only one detect at 0.0011 ppb from 489 total samples, further minimizing concern for change in cancer risk from exposure to drinking water.  Residues in drinking water are not expected to change significantly from registration of crop subgroups 20A and 20B as the application rates for crop group 20A and 20B are the same as the currently-registered representative crops and there are far higher acreage of rapeseed and sunflower as compared to the combined acreage of other commodities in crop subgroups 20A and 20B.  

At this time, there are no current or proposed residential uses for ethalfluralin.  Therefore, aggregate exposure and risk consist of only the dietary (food + water) pathway of exposure.  Aggregate acute, chronic and cancer risks are not of concern for the proposed and existing uses.

HED concludes that the proposed uses on Crop Groups 20A and B will not significantly increase aggregate exposures and risk estimates for ethalfluralin from the most recent risk assessment (Ethalfluralin:  Human Health Risk Assessment for (IR-4) Proposed Uses on Dill and Potato, J. R. Tomerlin, 11/2/07).  

Since the use pattern for Sonalan[(R)] 10G and Sonalan[(R)] HFP on rapeseed subgroup 20A and sunflower subgroup 20B is identical to the currently registered crops, occupational risk estimates will be the same as those for rapeseed seed and sunflower seed, and are not of concern.  

Adequacy of the Proposed Tolerances

The petitioner, IR-4, is proposing the following tolerances on the food commodities as shown below.

Commodity
Proposed Tolerance (ppm)
Current Tolerance for Representative Crop (ppm)
Rapeseed subgroup 20A
0.05 
0.05 (for Rapeseed, seed)
Sunflower subgroup 20B
0.05
0.05 (for Sunflower, seed)

Proposed tolerances for residues of ethalfluralin on crop subgroups 20A and 20B commodities are identical to the tolerances for this chemical on the currently-registered rapeseed seed and sunflower seed, which are representative commodities for those crop subgroups.  Since the use patterns on crop subgroups 20A and 20B commodities are the same as their representative crops, rapeseed seed and sunflower seed, HED agrees that these tolerance levels are appropriate.  At present, there is no Codex or European MRLs for ethalfluralin and therefore, there are no concerns for international harmonization. 

Conclusions

The toxicity database for ethalfluralin is considered complete except for an immunotoxicity study.  Adequate residue data are available to support the proposed use on crop subgroups 20A and 20B commodities, which have identical use patterns as the currently-registered representative commodities for those crop subgroups (rapeseed seed and sunflower seed).  There will be no increase in aggregate exposure or risk from food or drinking water sources as a result of the proposed use; aggregate risk estimates are not of concern for ethalfluralin based on the most recent comprehensive risk assessments for that compound.  Occupational exposures and risks are not of concern.  Therefore, HED has no objections to granting the proposed registration of Sonalan[(R)] 10G and Sonalan[(R)] HFP on crop subgroup 20A and crop subgroup 20B and establishing tolerances as described below with simultaneous revocation of ethalfluralin individual tolerances on  rapeseed, seed, sunflower, seed and safflower, seed.  

The Petitioner should revise the proposed tolerance expressions for ethalfluralin, as follows:

      Tolerances are established for residues of the herbicide, ethalfluralin, including its metabolites and degradates, in or on the commodities in the table below.  Compliance with the tolerance levels specified below is to be determined by measuring only the residues of ethalfluralin [ N -ethyl- N -(2-methyl-2-propenyl)-2,6-dinitro-4-(trifluoromethyl)benzenamine].
      
            
Commodity
Recommended Tolerance (ppm)
Rapeseed subgroup 20A
0.05 
Sunflower subgroup 20B
0.05
      
      
Ethalfluralin individual tolerances on rapeseed, seed, sunflower, seed and safflower, seed, each at 0.05 ppm should also be simultaneously revoked.