

EPA REGISTRATION DIVISION - COMPANY NOTICE OF FILING FOR PESTICIDE PETITION

Docket ID Number: EPA-HQ-OPP-2016-0651

EPA Registration Division Contact: Sidney Jackson (703) 305-7610

Interregional Research Project Number 4 

Pesticide Petition Number: 6E8510

   EPA has received a pesticide petition (PP), 6E8510, from the Interregional Research Project Number 4 (IR-4), IR-4 Project Headquarters, Rutgers, The State University of New Jersey, 500 College Road East, Suite 201 W, Princeton, NJ  08540 proposing in cooperation with Valent U.S.A. Corporation, 1600 Riviera Avenue, Suite 200, Walnut Creek, California 94596, pursuant to section 408(d) of the Federal Food, Drug, and Cosmetic Act (FFDCA), 21 U.S.C. 346a(d), to amend 40 CFR part 180 by:
      
 Establishing a tolerance for residues of the sum of clethodim, 2-[(1E)-1-[[[(2E)-3-chloro-2-propenyl]oxy]imino]propyl]-5-[2-(ethylthio)propyl]-3-hydroxy-2-cyclohexen-1-one, and its metabolites containing the 5-(2-ethylthiopropyl)cyclohexene-3-one and 5-(2-ethylthiopropyl)-5-hydroxycyclohexene-3-one moieties and their sulphoxides and sulphones, calculated as the stoichiometric equivalent of clethodim in or on the raw agricultural commodities Almond, hulls at 0.2 parts per million (ppm); Brassica, leafy greens, subgroup 4-16B at 3.0 ppm; Leaf petiole vegetable subgroup 22B at 0.60 ppm; Leafy greens subgroup 4-16A at 2.0 ppm; Nut, tree, group 14-12 at 0.2; Okra at 1.5 ppm;     Onion, green, subgroup 3-07B at 2.0 ppm; Stalk and stem vegetable subgroup 22A at 1.7 ppm; Vegetable, brassica, head and stem, group 5-16 at 3.0 ppm; and Vegetable, fruiting, group 8-10, except okra at 1.0 ppm; and


 Removing established tolerances for residues of the sum of clethodim, 2-[(1E)-1-[[[(2E)-3-chloro-2-propenyl]oxy]imino]propyl]-5-[2-(ethylthio)propyl]-3-hydroxy-2-cyclohexen-1-one, and its metabolites containing the 5-(2-ethylthiopropyl)cyclohexene-3-one and 5-(2-ethylthiopropyl)-5-hydroxycyclohexene-3-one moieties and their sulphoxides and sulphones, calculated as the stoichiometric equivalent of clethodim in or on the raw agricultural commodities Asparagus at  1.7 ppm; Brassica, head and stem, subgroup 5A at 3.0 ppm; Brassica, leafy greens, subgroup 5B at 3.0 ppm; Leaf petioles subgroup 4B at 0.60 ppm; Leafy greens subgroup 4A at 2.0 ppm; Onion, green at 2.0 ppm; Turnip, greens at 3.0 ppm; and Vegetable, fruiting, group 8-10 at 1.0 ppm.
      

EPA has determined that the petition contains data or information regarding the elements set forth in section 408(d)(2) of the FFDCA; however, EPA has not fully evaluated the sufficiency of the submitted data at this time or whether the data support granting of the petition.  Additional data may be needed before EPA rules on the petition.

A.  Residue Chemistry

       Plant metabolism.  The metabolism of clethodim is adequately understood for the 
      purpose of granting the proposed tolerances.

       Analytical method.  Practical analytical methods for detecting and measuring levels of clethodim have been developed and validated in/on all appropriate agricultural commodities and respective processing fractions.   The LOQ of clethodim in the methods is 0.2 ppm, which will allow monitoring of food with residues at the levels proposed for the tolerances.

       Magnitude of residues.  Residue data has been submitted which adequately support the requested tolerances.

B. Toxicological Profile

A summary of the toxicological endpoints for clethodim used for human risk assessment is discussed in EPA's January 30, 2014 Clethodim Preliminary Risk Assessment for Registration Review.  As noted the toxicology database for clethodim is complete and sufficient for selecting toxicity endpoints and points of departure (PODs) for risk assessment.  The acute reference dose (aRfD) of 1 mg/kg/day was calculated from the NOAEL from an acute neurotoxicity study and an uncertainty factor of 100X.  The chronic reference dose (cRfD) of 0.3 mg/kg/day was calculated from the NOAEL from the carcinogenicity study in mice and an uncertainty factor of 100X.  Clethodim is not carcinogenic so a cancer assessment was not performed.  The requirement for a subchronic inhalation study was waived by EPA (HASPOC, TXR 0056491, 2/20/2013).  

C. Aggregate Exposure

 Dietary exposure.  
   
      i.  Food. An acute and chronic dietary analysis was conducted to estimate exposure to potential clethodim residues in/on the following crops and food items: root and tuber vegetables, leaves of root and tuber vegetables, bulb vegetables, leafy vegetables, brassica leafy vegetables, legume vegetables (succulent and dry), fruiting vegetables, cucurbit vegetables, berries, cranberry, strawberry, asparagus, peanuts, cotton, sunflower, safflower, canola (rapeseed), flaxseed, hops, mint, sesame, basil, alfalfa, clover, field corn, and incurred secondary residues in meat, poultry, and milk.  All listed crops have approved tolerances, except for leaves of root and tuber vegetables.  EPA conducted a conservative unrefined assessment including tolerance levels residues and 100% crop treated were modeled with DEEM version 7.81 (G. Orrick, DP412704, 6/24/2013). 
        The addition of the proposed uses to the approved uses of clethodim is expected to make a negligible incremental contribution to the dietary burden and therefore, the risk assessment has not been repeated to include these minor uses.

      ii.  Drinking water. Drinking water concentrations were calculated by the Environmental Fate and Effects Division (EFED) using Pesticide Root Zone Model Ground Water (PRZM GW).  The highly conservative maximum screening-level acute and chronic Estimated Drinking Water Concentrations (EDWCs) of 1.43 and 1.15 ug/L, respectively) from the alfalfa use pattern were used in the dietary assessment.  Details can be found in EPA's January 30, 2014 Clethodim Preliminary Risk Assessment for Registration Review.

         a.  Acute Dietary (Food and Drinking Water) Exposure Results and Characterization  - Based on EPA's January 30, 2014 Clethodim Preliminary Risk Assessment for Registration Review, Dietary Risk Estimates (Food + Drinking Water), the acute dietary (food and drinking water) exposure is estimated at 10% of the acute Population Adjusted Dose (aPAD) for the general U.S. population and 29% of the aPAD for all infants (<1 year old), the population subgroup with the highest estimated acute dietary exposure to clethodim.
   
         b.  Chronic Dietary (Food and Drinking Water) Exposure Results and Characterization  -  Based on EPA's January 30, 2014 Clethodim Preliminary Risk Assessment for Registration Review, the chronic dietary (food and drinking water) exposure assessment is estimated at 12% of the chronic Population Adjusted Dose (cPAD) for the general U.S. population and 30% of the cPAD for all infants (<1 year old), the population subgroup with the highest estimated chronic dietary exposure to clethodim.

2.  Non-dietary exposure.  Clethodim is currently registered for use on several agricultural crops and a variety of non-food uses, including residential landscaped areas.  EPA noted in its 2014 Preliminary Risk Assessment for Registration Review short term residential exposure to Clethodim may occur from ornamental plants beds, landscapes, trees, shrubs and ground cover. The results of the aggregate assessment (food, water and residential) indicate that total short-term aggregate margins of exposure (MOEs) are not of concern (i.e. an MOE >= 100) with baseline attire (shorts, short-sleeved shirt, shoes and socks). 

D. Cumulative Effects  

Section 408(b)(2)(D)(v) requires that the Agency must consider "available information" concerning the cumulative effects of a particular pesticide's residues and "other substances that have a common mechanism of toxicity." EPA does not have, at this time, available data to determine whether clethodim has a common mechanism of toxicity with other substances or how to include this pesticide in a cumulative risk assessment.  For the purposes of this tolerance action, EPA has not assumed that clethodim has a common mechanism of toxicity with other substances.

E. Safety Determination  

FFDCA section 408 provides that EPA shall apply an additional margin of safety, up to ten-fold, for added protection for infants and children in the case of threshold effects, unless EPA determines that a different margin of safety will be safe for infants and children.  The toxicological database for evaluating prenatal and postnatal toxicity for clethodim is complete with respect to current data requirements, and there are no special prenatal or postnatal toxicity concerns for infants and children.  EPA has concluded that reliable data support reduction of the FQPA Safety Factor for protection of infants and children to 1X.   

       U.S. population. 
Based on EPA's January 30, 2014 Clethodim Preliminary Risk Assessment for Registration Review, Dietary Risk Estimates (Food + Drinking Water), the acute and chronic dietary (food and drinking water) exposure is estimated at 10% and 12% of the acute and chronic Population Adjusted Dose, respectively, for the general U.S. population.  Aggregate exposures below 100% of the cPAD are generally considered to represent a reasonable certainty of no harm to exposed populations.  Valent USA concludes that there is a reasonable certainty that no harm will result to the U.S. population (or any sub-populations) by including the incremental additional exposure resulting from the proposed uses of clethodim.

       Infants and children.  Based on EPA's January 30, 2014 Clethodim Preliminary Risk Assessment for Registration Review, Dietary Risk Estimates (Food + Drinking Water), the acute and chronic dietary (food and drinking water) exposure is estimated at 29% and 30% of the acute and chronic Population Adjusted Dose, respectively, for the general U.S. population.  Aggregate exposures below 100% of the cPAD are generally considered to represent a reasonable certainty of no harm to exposed populations.  Valent USA concludes that there is a reasonable certainty that no harm will result to the U.S. population (or any sub-populations) by including the incremental additional exposure resulting from the proposed uses of clethodim.

F. International Tolerances 

The U.S. residue definition is harmonized with Codex, but not Canada.  Canada's tolerance expression includes clethodim and its metabolites containing the 2-cyclohex-1-enone moiety, but does not include the sulphoxides and sulphones.   

The following Codex Maximum Residue Limits (MRL) have been established for clethodim.

                                   Commodity
                                Codex MRL (ppm)
Bean, dry
                                      2.0
Onion, bulb, subgroup 3-07A
                                      0.5
Peanut
                                      5.0
Potato
                                      0.5
Sugar beet, roots
                                      0.1
Sunflower, seed
                                      0.5
Tomato
                                      1.0

