Page 1 of 26 **UNITED STATES ENVIRONMENTAL PROTECTION AGENCY WASHINGTON, D.C. 20460**  **OFFICE OF CHEMICAL SAFETY AND POLLUTION PREVENTION**  **MEMORANDUM** Date: August 31 , 2010 Subject: Glufosinate Ammonium . Petitions for the Establis hment of Permanent Tolerances in/on Citrus Fruits (Crop Group 10), Pome Fruits (Crop Group 11 ), Stone Fruits (Crop Group 12) , Olives and Sweet Corn . Summary of Analy tical Chemistry

and Residue Data. **PC Code:** 128850 **DP Barcode No.:** D372625 **Decision No.:** 42439 7 **Registration No. :**  264 - 646 **Petition No.:** 9F7655 and 9E7604 **Regulatory Action:** Tolerance Petition **Risk Assessment Type:** Residue Chemistry **Case No.:** NA **T XR No.:**  NA **C AS No.:**  77182 - 82 - 2 **MRID No.:** 47915701, 4791570 2 , 4791570 3 , 4791570 4 , 4791570 5 , 47915706, 47915707, 47915708, 47828201 , 47828202 and 47828203 **40 CFR:** §180. 473

**FROM :**  Id eliz Negrón - Encarnación, Ph.D., Chemist

Risk Assessment Branch V Health Effects Division (7509P) **THROUGH :**  William H. Donovan, Ph.D., Chemist

Risk Assessment Branch V Health Effects Division (7509P) Jack Arthur, Chief Risk Assessment Branch V Health Effects Division (7509P ) **TO :**  Sidney

Jackson, Barbara Madden, RM Team 05 James Stone, RM Team 23 R egistration D ivision (RD) (7505P) Tom Myers, Risk Manager Pesticide Re - E valuation Division (PRD) (7508P)Glufosinate Ammonium Summary of Analytical Chemistry and Residue Data D372625

Page 2 of 26 **Executive Summary** Technical glufosinate ammonium is a racemic mixt ure of the D and L enantiomers; only the L enantiomer is herbicidall y active. The compound is a non - selective herbicide and acts as an inhibitor of glutamine sy

nthetase which leads to poisoning of the plant by ammonia. Glufosinate ammonium is currently

r egistered for use on both transgenic and nontransgenic crops. The transgenic plants currently registered (canola, sugar beet, corn, soy bean) and the transgenic plants requested for registration (rice and cotton) have been engineered to express phosphiothrion acetyl - transferase (PAT) which enables the plant to metabolize glufosinate ammonium into N acetyl - glufosinate. The petitioners have proposed application of L iberty® 280 SL (24.5 % glufosinate ammonium; soluble concentrate; EPA Reg. No. 264 - 829 ) to Citr us Fruits (Crop Group 10), Pome Fruits (Crop Group 11), Stone Fruits (Crop Group 12) and Olives . However, the crop field trials were performed with RELY 200SL(18.19% glufosinate ammonium; soluble concentrate; EPA Reg. No. 264 - 660). For the intended purp ose of establishing tolerances, the RELY 200SLdata will be considered acceptable to amend the Liberty label to included uses for the mentioned RACs. The Li berty® label may

include use directions to support a three applications to the soil at a maximum rate of 1.5 lb ai/A , 14 - day retreatment interval ( RTI ) , and 14 - day pre harvest interval ( PHI ) for citrus fruits, pome fruits and olives for a maximum seasonal rate of 4.5 lb ai/A . For stone fruits, the studies submitted support two applications to the soil with a m aximum rate of 1.5 lb ai/A, 28 - day

RTI , and 14 - PHIfor a maximum seasonal rate of 3.0 lb ai/A. The product label prohibits application through irrigation equipment and by aircraft. The Interregional Research Project No 4 submitted crop field tria l data to support the use of glufosinate ammonium on transgenic sweet corn. Twelve crop field trials were conducted in EPA regions 1, 3, 5, 10 and 11. Two foliar applications of L iberty Herbicide at a rate of 0.375 lb ai/A for a total of 0.75 lb ai/A wer e performed with a retreatment interval (RTI) of 14 - 1 6 day s. Ammonium sulfate was included in the tank mix. Sweet corn ears, forage and stover were harvested 30 to 50 day s following the final application. Stover was dried for 5 to 13 day s after harvest. Based on the metabolism and magnitude of the residue studies, the Metabolism Assessment Review Committee (MARC) concluded that the residues of concern in the crops studied, for tolerance expression and risk assessment purposes, are glufosinate ammonium, N - acetyl - glufosinate, and glufosinate propanoic acid (D282757, T. Bloem, 9 - May- 2002). HED concludes that the results from the currently

available metabolism studies may be translated to citrus fruit s, pome fruits, stone fruits, olives and sweet corn . A dequate enforcement and multiresidue analy tical methods are available for glufosinate ammonium, N - acetyl glufosinate, and glufosinate propanoic acid . Inthe current studies, r esidues of glufosinate amm onium, N - acetyl - glufosinate, and glufosinate propanoic acid were determined using one of three methods . A Gas Chromatography (GC) with flame photometric detection method currently

used for enforcement purposes (BK/01/99) was used for the analy sis of peach samples. A method very

similar to the enforcement method HRVA - 5 was used for the analy sis of sweet corn samples. A Li quid Chromatography /Mass Spectrometry

/Mass Spectrometry ( LC /MS/MS ) method developed by Bayer was used for the analy sis of orange, lemon, grapefruit,Glufosinate Ammonium Summary of Analytical Chemistry and Residue Data D372625

Page 3 of 26 prune, pear, cherry , olive, olive oil, orange oil and prunes . The method described in Bayer CropScience report number GL - 001 - P07 - 01 , “ An Analy tical Method for the Determination of Residues of Glufosinate in Crop Matrices Using L C/MS/MS ” residues were quantitated by liquid chromatography

/mass spec troscopy

/mass spectroscopy ( LC /MS/MS ). The limit of quantitation (LOQ) is reported to be 0.0 5 ppm for each analy te . The method was adequate for data collection based on concurrent method recoveries. Control samples were fortified with glufosinate ammonium, N - acetyl - glufosinate, and glufosinate propanoic acid at 0.05, 0.5 ppm for all commodities . All recoveries were between the acceptable range of 70 - 120 % . With the current petition, f rozen storage stability was demonstrated for glufo sinate residues in pe aches stored frozen for 730 day s (24.3 months) and N - acetylglufosinate and 3 - methylphosphinico - propanoic acid residues stored frozen for 778 days (25.9 months). Previously submitted and reviewed frozen storage stability data indicate that glufosinate ammon ium and glufosinate propanoic acid are stable for 730 day s on frozen apples, corn grain, and soy beans (PP#8F3607, J. Garbus, 8 - Aug - 1990) , and for 24 months on oranges and 6 months on kiwi. Blueberry storage stability

data results showed that glufosinate ammonium and glufosinate propanoic acid were stable in/on frozen blueberry samples for 693 day s and 664 day s, respectively

(D271110, T. Bloem, 20/June/2002). Additional storage stability data indicated that glufosinate ammonium, N - acetylglufosinate, and gl ufosinate propanoic acid are stable for 12 months on transgenic soy bean seed, forage and hay ; for 3 months on soy bean oil and meal; for 6 months on transgenic corn grain, fodder and forage; and for 24 months on transgenic sugar beet tops and roots (D211531 and D219069, M. Rodriguez, 7 - Mar - 1996; D257629, T. Bloem, 9 - Jul 1999 ). These data are adequate to validate the storage interval and conditions for the samples analy zed as part of the current study . **Regulatory Recommendations and Residue Chemistry Deficiencies**  Provided revised Section B and F are submitted as specified below there are no residue chemistry deficiencies that would preclude granting a registration for the requested uses of glufosinate ammonium on citrus fruit s, pome fruits, stone fruits, olives and sweet corn . The submitted data support the following tolerance s for glufosinate ammonium residues of concern in/on the following raw agricultural commodit ies :

Citrus f ruit (CG 10) ................................ ................ ... 0.1 5 ppm Pome f ruit (CG 11) ................................ .................... 0.25 p pm Stone f ruit (CG 12) ................................ ................... 0.25 ppm Olives ................................ ................................ ......... 0.15 ppm Corn, sweet, kernels plus cob with husks removed .... 0.25 ppm Corn, s weet, f

orage ................................ ....................... 1.6 ppm Corn, s weet, s tover ................................ ......................... 10 ppm A revised human health risk assessment including glufosinate ammonium uses on citrus fruit s , pome fruits, stone fruits, olives and sweet corn is being prepared as a separate document. Revised Section B - Label use directions should match crop field trial use pattern to include maximum application rates, RTI , and adjuvant uses.Glufosinate Ammonium Summary of Analytical Chemistry and Residue Data D372625

Page 4 of 26 Revised Section F

– Proposed crop commodity definitions and tolerance levels should be revised to those recommended in Table 9. **Background** The chemical structure and nomenclature of glufosinate ammonium, N - acetyl - glufosinate, and glufosinate propanoic acid are presented in Table 1 while the phy sicochemical properties are presented in Table 2. **TABLE 1. Test Com** **pound Nom enclature.**  Compound

P N H 2 O O H O C H 3 - O N H 4 + Common name Glufosinate ammonium Company experimental name AE F039866 , HOE 039866 IUPA C name ammonium - DL - homoalanin - 4 - yl - (methyl) - phosphinate CAS name butanoic acid, (±) - 2 - amino - 4 - (hydroxymethylphosphinyl) - , monoammonium salt CAS registry number 77182 - 82 - 2 End - use product (EP) RELY 200 SC Compound

P HO C

H 3 O O

H O Common name Glu - PPA , AE F061517, G lufosinate propanoic acid , HOE 061517 Chemical name 3 - methylphosphinico - propionic acid or 3 - (Hydroxymethylphosphinyl) propanoic acid Compound

P H O CH 3 O O

O H N H CH 3 O

Common name Glu - NAG, AE F085355, N - acetylglufosinate, HOE 099730 Chemical name 2 - (Acetylamino) - 4 - (hydroxymethyl phosphinyl) butanoic acidGlufosinate Ammonium Summary of Analytical Chemistry and Residue Data D372625

Page 5 of 26 **Table 2. Physicochem** **ical Properties of the Technical Grade Test Com pound.** 

Parameter Value 1 Melting point/range (°C) 215 - 218 pH 4.7 Density (g/cm3 ) 1.32 Water solubility (g/L at pH 5) 13 70 Solvent solubility at room temp (g/L) methanol: 5.73; DMSO: 0.049; polyethylene glycol: 0.047; acetonrile, toluene, acetone, ethyl acetate, and hexane: <0.00025 Vapor pressure at 25 ° C (torr) <7.50 x 10 - 9 Dissociation constant, pK a 9.15 ± 0.07 Octanol/water partition coefficient (Log KOW) 9.77 x 10 - 5 UV/visible absorption spectrum (nm) >190 1 Source: D ER for MRID 46573701, Tom Bloem, 2005 **860.1200 Directions for Use**  For the application of glufosinate ammonium in/on citrus, pome fruit, stone fru it and olives, the petitioner has submitted undated draft labels in conjunction with each petition for the 2.34 lb/gal SL formulation ( Li berty® 280 SLHerbicide ; EPA Reg. No. 264 - 829 ). A summary of the proposed/registered crop use patterns in this document is listed in Table 3. Li berty® 280 SLHerbicide is presently registered for use on canola, field corn, silage corn, cotton, soy

bean, bushberries, lingonberry , juneberry , salal, tree nuts, grape vineyards and potato. T he petitioner submitted residue fi eld trials to establish tolerances for glufosinate ammonium and two metabolites in/on citrus, pome fruit, stone fruit and olives . For this RELY 200, a soluble concentrate formulation containing 1.64 lb ai/A was applied to the soil near the base of the tre es. IR - 4 submitted field trials to support the use of glufosinate ammonium in/on transgenic sweet corn. With this purpose, f oliar applications of L iberty® Herbicide on transgenic sweet corn were performed. End - use products equivalent to the L iberty® Her bicide may

be registered for use on transgenic sweet corn based on the data generated in these crop field trials.Glufosinate Ammonium Summary of Analytical Chemistry and Residue Data D372625

Page 6 of 26 **Table 3**  **. Summary of Directions for Use of**  **Glufosinate Am mo**  **nium (2.34 lb/gal; EPA Reg. No. 352**  **- 515)**  **. 1**  Applic. Timing, Type, and Equip. Appl ic. Rate

(lb ai/A) Retreat.

Interval (days) Max. No. Applic. Per Season Max. Seasonal

Applic. Rate (lb ai/A) PHI

(days) Adjuvant Use Directions

and Limitations

Broadcast, banded or spot treatment Stone Fruit Do not apply this product through any type of irrigation system. Do not apply this product aerially. Do not graze, harvest, and/or feed treated orchard cover crops to livestock. Do not make spot spray applications to suckers. **1.5 28**  **2** 3.0 14 non - ionic antifoam

2 Pom e Fruit **1.5 14**  **3** 4.5 14 non - ionic antifoam

2 Citrus **1.5 14**  **3** 4.5 14 non - ionic antifoam

2 Olives **1.5 14**  **3** 4.5 14 non - ionic antifoam

2 Foliar treatment Transgenic Sweet Corn Must be applied with ammonium sulfate. 0.3 65 **1 4**  2 0.73 50 **Do not use** 1 The numbers in bold are not in the label but correspond to the use pattern proposed based on the field trials. 2 A non - ionic antifoam adjuvant may be added to the tank mixture at the application rate used in the field trials. Conclusions . The proposed use directions s hould specify the maximum application rate and retreatment interval; therefore, the petitioner may revise the product label to specify the conditions used in the field trials studies. The Li berty® label may include use directions to support a three applic ations to the soil at a maximum rate of 1.5 lb ai/A, 14 - day retreatment interval (RTI ), and 14 - day pre harvest interval (PHI) for citrus fruits, pome fruits and olives for a maximum seasonal rate of 4.5 lb ai/A. For stone fruits, the studies submitted sup port two applications to the soil with a maximum rate of 1.5 lb ai/A, 28 - day RTI , and 14 - PHIfor a maximum seasonal rate of 3.0 lb ai/A. A non - ionic antifoam adjuvant was included in the herbicide mixture in some field trials for citrus fruits, peach, plum, pear and olives; therefore, the use directions may

include the use of this adjuvant on the crops specified but the corresponding use rate should reflect the one used in the crop field trials. For transgenic sweet corn, the crop field trials support the following use pattern: two foliar applications of L iberty Herb icide at a maximum rate of 0.365 lb ai/A for a total seasonal maximum rate of 0.7 3 lb ai/A, a 14 - day RTI , and a 50 - day

PHIfollowing the final application. Moreover, as stated in the label use directions for sweet corn, ammonium sulfate must be added to the pesticide mixture. **860.1300 Nature of the Residue –**  **Plants and Livestock**  No plant or animal metabolism data were submitted with the subject petitions. The nature of the residue of glufos inate ammonium in livestock and plants has been adequately delineated. HED has previously

reviewed metabolism studies conducted with nontransgenic (corn, soy bean, apple,Glufosinate Ammonium Summary of Analytical Chemistry and Residue Data D372625

Page 7 of 26 and lettuce; 8F3607, J. Garbus, 14 - Oct - 1988 & 8 - Aug - 1990) and transgenic (corn, soy be an, sugar beet, canola, and rice; D227386, M. Rodriguez, 7 - Mar - 1996; D257629, T. Bloem, 9 - Jul 1999; 45204405.der.wpd) crops. The transgenic corn, soy bean, sugar beet, canola, and rice investigated in the metabolism studies were engineered to express PAT which acetylates glufosinate (herbicidally

active) to form N - acetyl - glufosinate (not herbicidally active). Based on the metabolism and magnitude of the residue studies, the Metabolism Assessment Review Committee (MARC) concluded that the residues of conc ern in the crops studied, for tolerance expression and risk assessment purposes, are glufosinate ammonium, N - acetyl - glufosinate, and glufosinate propanoic acid (D282757, T. Bloem, 9 - May- 2002). HED concludes that the results from the currently

available me tabolism studies may be translated to citrus fruit, pome fruit, stone fruit and sweet corn . Glufosinate propanoic acid was the only metabolite identified in the nontransgenic studies (2 - 40% total radioactive residue (TRR); only soy bean leaf, corn stove r, and apples were analy zed). The petitioner demonstrated that 40% of the TRR in nontransgenic corn stover was incorporated into protein, starch, cellulose, and lignin. Glufosinate ammonium, N - acetyl - glufosinate, and glufosinate propanoic acid were the m ajor residues identified in the transgenic crops (40 - 98% of the TRR). The petitioner demonstrated that for transgenic sugar beet leaves, surface residues are composed of a nearly

equal mixture of the D and L enantiomers of glufosinate ammonium while interior residues are composed of almost exclusively D enantiomer of glufosinate ammonium. This indicates that only

the Lenantiomer of glufosinate ammonium was acetylated to form N acetyl - glufosinate. There are no feedstock item s associated with this petiti on; however, the nature of the residue in livestock commodities has been assessed and have been determined to be the same as in plants ( D271110, T. Bloem, 20/June/2002 ). **860.1340 Residue Analytical Methods** Enforcement methods D335330 , T. Bloem, 09/12/2 007 Two analy

tical methods have been validated by the Analy

tical Chemistry

Branch (ACB) for enforcement of the currently established tolerances: **(1)** method HRAV - 5A was validated by ACB for the determination of glufosinate ammonium and glufosinate propano ic acid in/on apple, grape, almond, soy

bean seed, corn grain, and corn forage (PP# 8F3607, J. Garbus, 14 - Sep - 1989) and **(2)** method BK/01/99 was validated by ACB for determination of glufosinate ammonium, N acetyl - glufosinate, and glufosinate propanoic acid in/on canola seed and sugar beet root (D258420, T. Bloem, 19 - Aug - 2000). Both methods involve extraction with water, anion exchange chromatography , derivatization with trimethylorthoacetate, silica - gel column clean - up, and quantification via gas chromatogr aphy with flame photometric detection (residues expressed as glufosinate free acid equivalents). Method BK/01/99 includes a cation ion - exchange column prior to derivatization which fractionates glufosinate ammonium and N - acetyl - glufosinate and allows for speciation of these compounds (both compounds are derivitized to the sameGlufosinate Ammonium Summary of Analytical Chemistry and Residue Data D372625

Page 8 of 26 compound). This step can be eliminated if separation of these two compounds is unnecessary . The methods do not distinguish between the D and L enantiomers of glufosinate ammonium and N - acetyl - glufosinate. Based on the similarity

in the two methods and the results from the petition method validations (PMVs), HED concludes that method BK/01/99 is a suitable method for enforcement of sweet corn, stone fruit, pome fruit, citrus fruit and olive tolerances. Data - collection methods Three methods were used for quantitation of glufosinate ammonium and its two metabolites. For peach samples, r esidues of glufosinate ammonium and its two metabolites, 3 - methylphosphinico propanoic acid an d N - acetylglufosinate were analy zed from their derivatives AE F064706 and AE F070951 by

using a gas chromatograph equipped with a flame photometric detector operating in the phosphorous mode. This method is equivalent to the enforcement method BK/01/99 but instead of following the general procedure, the optional speciation process (optional method, Section 3.2) is followed to quantify the parent and its two metabolites separately . Quantitation is based on the use of a calibration curve. The limit of quantitation for each analy te is 0.05 ppm. Concurrent recovery

data was obtained for peach samples by spiking the samples with the corresponding standards before the extraction process. For sweet corn, a similar method to the enforcement method HRVA - 5 was us ed for quantitation . Inthis method the analy

tes were extracted from samples with deionized water , the sample was cleaned through an anion exchange resin, derivatized with trimethylorthoacetate/glacial acetic acid to AE F064706 and AE F070951 , and cleaned through a silica solid phase extraction column . The parent and N - acetylglufosinate are derivatized to the same analy te, AE F064706 , while glufosinate propanoic acid is derivatized to AE F070951 . The residues were subsequently measured by

gas chromatograp hy with flame photometric detection in phosphorous mode , and reported as glufosinate free acid equivalents . Modifications were performed to add clarity to the extraction procedure. T o prove the extraction efficiency in sweet corn , this method was validate d by

obtaining recoveries of glufosinate ammonium and glufosinate propanoic acid but to support it u se in transgenic sweet corn IR - 4 submitted with the current petition recovery data for N - acetylglufosinate. The method was validated with triplicate sample s of sweet corn ears at levels 0.0480 and 0.480 ppm, forage at 0.048 and 1.06 ppm, and stover at 0.048, 0.480 and 5.32 ppm. The recoveries of N - acetylglufosinate in/on sweet corn were between 78% and 113% for all matrices. The method L OQ was determined t o be 0.05 ppm for each analy te. For orange, lemon, grapefruit, cherry , plum, pear and olive, r esidues were determined using a method described in Bayer Report Number GL - 001 - P07 - 01 , “ An Analy tical Method for the Determination of Residues of Glufosinate in Crop Matrices Using LC/MS/MS ” . Orange, lemon, grapefruit, cherry , plum, pear and olive raw agricultural commodities and processed samples were analy

zed for residues of glufosinate ammonium and its two metabolites, glufosinate propanoic acid and N - acetylgl ufosinate using liquid chromatography with tandem mass - spectral detection (L C/MS - MS) (Method Number GL - 001 - P07 - 01).Glufosinate Ammonium Summary of Analytical Chemistry and Residue Data D372625

Page 9 of 26 Briefly , for extraction from orange, lemon, grapefruit, cherry , plum, pear and olive RACs and prunes process commodity , a sub - sample was extracted by shaking the sample in the presence of water for 30 minutes at room temperature. An internal standard was added to the sample vial and then an aliquot of the extract was mixed with methanol and purified through a SAX SPE column. The eluent was dried, reconstitut ed, and injected onto the L C/MS/MS for quantification of the residues. For e xtraction of the olive o il and citrus oil matrix , an oil aliquot was dissolved into hexane and shake in the presence of water at room temperature two separate ti mes. The water layers were decanted and combined. An aliquot of the water extract was mixed with acetone and evaporated to dry

ness. The residue was reconstituted into 1 mLdiluting solvent (85:15 mixture of acetonitrile/diluting buffer) and injected onto L C/MS/MS . An electrospray interphase in positive mode was used for ionization of the sample. Since the analy tes elute at a similar retention time, specificity is achieved by mult iple reaction monitoring of glufosinate ammonium (152.7/134.0 m/z), N - acetylg lufosinate (223.7/117.0 m/z) and glufosinate propanoic acid (155.7/137.0 m/z) . Qu antification of the residues was based on the use of a calibration curve and the deuterated analy

tes as internal standards. Based on the lowest level of method validation (LLM V), the limit of quantitation (L OQ) was 0.05 ppm for each analy te. C oncurrent method recovery data was obtained for c itrus , pome fruit, stone fruit and olive raw agricultural and processed commodities . The recovery

of the parent and its two metabolites was based on relative recovery studies in which a known amount of the analy te and deuterated analy

te were added during the sample preparation process and the recovery was calculated by

measuring the response of the analy te with respect to its deuterated f orm. For orange, lemon, grapefruit, cherry , plum, pear, peach and olive , the method was validated for glufosinate ammonium and its two metabolites at levels of 0.0 5 ppm and 0.5 0 ppm. The average recoveries obtained from these commodities were between 78.7 % and 110%. For orange oil, olive oil and plums, the method was validated at 0.05 ppm and at 0.8 ppm only

for plum. The average recoveries were within 80.3% and 112%. Average recoveries for all RAC and processed commodities were within the acceptable range of 70 - 120% . Conclusions . There are adequate residue analy tical methods for tolerance enforcement. Also, the method s used for data collection was adequate based on the method recoveries , precision and the range of levels tested which included the LO Q and tolerance level . **860.1360 Multiresidue Methods** Glufosinate ammonium, glufosinate propanoic acid , and N - acetyl - glufosinate were not quantitatively

recovered from any

of the FDA Multiresidue Testing Protocols. This information has been forwarded to FDA (PP#8F3607, J. Garbus, 14 - Aug - 1988; PP#5F4578, M. Rodriguez, 10 - Oct - 1995).Glufosinate Ammonium Summary of Analytical Chemistry and Residue Data D372625

Page 10 of 26 **860.1380 Storage Stability** Reference DER s : 47828201.der.doc and 47915705.der.doc. Previously

submitted and reviewed frozen storage stability data indicate that gluf

osinate ammonium and glufosinate propanoic acid are stable for 24 months on frozen apples, corn grain, and soy beans (P P#8F3607, J. Garbus, 8 - Aug - 1990), for 24 months on oranges and 6 months on kiwi ( study

pending approval ) . Moreover, blueberry storage sta

bility data was submitted with the petition for tolerances in the bushberries crop group (D271110, T. Bloem, 20/June/2002). The results showed that glufosinate ammonium and glufosinate propanoic acid were stable in/on frozen blueberry

samples for 693 day s and 664 day s, respectively . Additional storage stability data indicated that glufosinate ammonium, N - acetyl glufosinate, and glufosinate propanoic acid are stable for 12 months on transgenic soy bean seed, forage and hay ; for 3 months on soy bean oil and me al; for 6 months on transgenic corn grain, fodder and forage; and for 24 months on transgenic sugar beet tops and roots (D211531 and D219069, M. Rodriguez, 7 - Mar - 1996; D257629, T. Bloem, 9 - Jul - 1999). Frozen storage stability

for glufosinate residues was investigated in peaches stored frozen for 730 day s (24.3 months) and N - acetylglufosinate and 3 - methylphosphinico - propanoic acid residues stored frozen for 778 day s (25.9 months) under the same storage conditions as those of the field samples . The storage stability study started when the field samples arrived at the analy tical laboratory

the fortified samples were stored under the same conditions as the field samples. Average storage stability

results ranged from 87 % to 95% for glufosinate ammonium , from 70 % to 78% for 3 - methylphosphinico - propanoic acid, and from 77 % to 80% for N - acetylglufosinate. However, the storage stability period do not cover the actual storage duration for peaches, 791 day s (26 months). The number of day s not covered by the storage stability

studies was 61 for glufosinate ammonium and, 13 for 3 - methylphosphinico - propanoic acid and N - acetylglufosinate. Since the storage stability recoveries for glufosinate ammonium were quite high and just a few day s were not covered for the two meta bolites, on this time HED will considered the peach storage period covered by the interval of demonstrated storage stability . Storage stability

was also demonstrated in sweet corn ears (765 and 914 days)), forage (793 day s) and stover (812 day s) spiked w ith glufosinate ammonium and glufosinate propionic acid at < - 10 o C. Average storage stability results were from 64.2 to 92.4% while the results corrected for the mean concurrent recoveries were from 89.1 to 112% after over two years of frozen storage. T his storage stability

study support the stability

of glufosinate and glufosinate propionic acid for 914 day s for ears, and 793 day s for forage and 812 day s for stover. Based on the storage stability results the interval of demonstrated storage stability w ill be considered to cover the sweet corn storage period for ears (197 - 950 day s), forage (146 - 788 day s) and stover (143 - 810 day s) samples. The stability

of the N - acetylflufosinate was not assessed during this study which is a metabolite relevant to transg enic sweet corn. Previous storage stability studies performed up to 6 months on nontransgenic field corn show the stability of this residue but this interval do not covers the study period. However, the stability of N - acetylglufosinate in peach samples w as demonstrated up to 778 day s which covers the storage period of 10 of the 12 samples of sweet corn ears and most of the forage and s tover samples; therefore, the sweet corn data will be considered acceptable for the current petition.Glufosinate Ammonium Summary of Analytical Chemistry and Residue Data D372625

Page 11 of 26 To translate storag e stability data to all RACs, HED guidelines require that stability is proven for at least five diverse crops. Indeed, the data available covers this requirement: oilseed (transgenic soy bean seed, 12 months), nonoi ly grain (transgenic corn grain for 6 months and nontransgenic corn grain for 24 months (N - acetylglufosinate not assessed) ), fruit or fruiting vegetable (orange for 24 months and blueberries for 21.8 months , N - acetylglufosinate not assessed), leafy vegetable (sugar beet tops, 24 months), and root crop (sugar beet root, 24 months). Based on the available storage stability data and since acceptable percent recoveries were attained for fortified samples run concurrent to the treated samples, HED concludes that the storage intervals and conditions fo r the samples collected as part of the orange, lemon, grapefruit, cherry , plum, pear, peach and olive field trial s are acceptable. The storage durations and conditions of samples from the crop field trials submitted to support th ese petition s are presente d in Table 4 . The storage stability

of glufosinate ammonium, glufosinate propanoic acid and N acetylglufosinate has been established in some processed commodities. These are stable under frozen conditions for 3 m onths on soy bean oil and meal, and for 9 m onths on sugar beet pulp, molasses, and sugar beet refined sugar (D211531 and D219069, M. Rodriguez, 7 - Mar - 1996; D286447, T. Blo em, 11 - Dec - 2002). Storage stability studies for olive oil, orange oil and prunes processed commodities haven’t been submitted w ith the current petition. These studies are recommended in OPPTS 860.1380 and OPPTS 860.1520 guidelines. However, under certain circumstances HED waives these studies. The storage intervals for olive oil (3.7 months) and prunes (4.4 months) can be suppo rted based on the available storage stability studies for soy

bean oil and a wide variety

of RACs. The orange oil commodity was stored for 9.2 months. Storage stability for orange oil will not be requested at this time based on the following: residue leve ls were <LOQ in the RAC and processed commodity after applying exaggerated rates (5x) of the end use product, and storage stability has been demonstrated on a wide variety of RACs for at least 2 years and some processed commodities for at least 9 months.Glufosinate Ammonium Summary of Analytical Chemistry and Residue Data D372625

Page 12 of 26 **TABLE 4 .**  **Summary of Storage Conditions.** Matrix (RAC) Analytes Storage Tem p (°C) Actual Storage

Duration 1 Interval of Demonstrated Storage Stability (months) Citrus, fruit Glufosinate

ammonium, and Glufosinate Propanoic Acid <0 336 days (11.2 months) Concurrent s torage stability data was

submitted for residues in/on peach showing a stability period of 730 days for g lufosinate ammonium, and 778 days for glufosinate propanoic acid , and N - acetylglufosinate (MRID 47915705). In ad dition, concurrent studies in transgenic sweet corn were submitted showing stability of glufosinate and glufosinate propanoic acid for 914 days in ears, 793 days in forage and 812 days in stover (MRID 47828201). Glufosinate ammonium and glufosinate propanoic acid : Apple, corn grain, and soybean for 730 days (PP#8F 3607, J. Garbus, 8 - Aug - 1990), blueberries for 664 days (D271110, T. Bloem, 20/June/2002) , orange for 24 months and kiwi for 6 months ( study pending approval ). Glufosinate ammonium, glufosinate propanoic acid , and N - acetylglufosinate: 12 months on transgenic soybean seed, forage, and hay; for 3 months on soybean oil and meal; for 6 months on transgenic corn grain, fodder, and forage; and for 24 months on transgenic sugar beet tops and roots ; for 9 months on sugar beet pulp, molasses, and sugar beet refined sugar (D211531 and D219069, M. Rodriguez, 7 - Mar - 1996; D257629, T. Bloem, 9 - Jul - 1999 ; D286447, T. Bloem, 11 - Dec - 2002 ). Trans. Sweet Corn, Ears 197 - 950 days (9.6 - 31.2 months) Trans. Sweet Co rn, Forage 146 - 788 days (4.9 - 26.3 months) Trans. Sweet Corn, Stover 143 - 810 days (4.8 - 27 months) Pear Glufosinate

ammonium, 3 - methylphosphinico propanoic acid, and N - acetylglufosinate 224 days (7. 5 months) Cherry 332 days (11.1 months) P lum 281 days (9.4 months) Olive 259 days (8.6 months) Orange, Fruit (Processing Studies) 176 days ( 5.9 months ) Orange, Oil 274 - 277 days ( 9.1 - 9.2 months) Plum (Processing Studies) 1 35 - 14 6 days (4.5 - 4.9 months) Prune 128 - 133 days (4 .3 - 4.4 months) Olive Fruit (Processing Studies) 122 - 125 days ( 4.1 - 4.2 months) Olive Oil 109 - 111 days ( 3.6 - 3.7 months ) 1 Actual storage duration from harvest to extraction. Conclusions . There are adequate storage stability data available in a wide variety of crops which can be translated in the current petition s for orange, lemon, grapefruit, cherry , plum, pear, peach and olive RACs , and citrus oil, prunes and olive oil processed commodities to validate sample storage conditions and durations . However, the petitioner is reminded that storage stability studies are recommended for processed commodities. In addition, these studies should cover the period of time in which the RAC or processed commodity was stored. For N - acetylglufosinate in/on transgenic sweet corn, the concurrent and previous storage stability studies do not cover the storage interval. This deficiency needs to be resolved.Glufosinate Ammonium Summary of Analytical Chemistry and Residue Data D372625

Page 13 of 26 **860.1400 Water, Fish, and Irrigated Crops** T here are no proposed uses that are relevant to this guidel ine topic . However, glufosinate ammonium has uses registered for rice (D271110, T. Bloem, 20 - June - 2002). **860.1460 Food Handling** There are no proposed uses that are relevant to this guideline topic . **860.1480 Meat, Milk, Poultry, and Eggs** No new animal feeding studies were submitted with these petitions and only sweet corn forage and stover are associated with feedstuff items . Inaddition , glufosinate ammonium has uses registered for feedstuff (D271110, T. Bloem, 20 - June - 2002). InJune 2008 an u pdate t o the Table 1 of OPPTS 860.1000 was issued. T herefore, the dietary burden to livestock was calculated based on the updated values of Table 1 and the use of sweet corn feedstuff . **Table 5. Calculation of M**  **axim um**  **Livestock D**  **ietary B**  **urden for Glufosinate Am**  **mo nium**  **.** Feedstock Tolerance %Dry Matter % of Diet Burden (ppm) 2 Dairy Cattle Sweet Corn Stover (R) 10 83 15 1.81 Field Corn Forage (R) 4.0 40 30 0.03 Field Corn Grain (CC) 0.20 88 15 3.00 Beet Sugar Molasses (CC) 5.0 75 10 0.67 Rice Grain (CC) 1. 0 88 20 0.45 Undelinted Cottonseed (PC) 4.0 88 10 0.23 TOTAL 100 **6.19**

Beef Cattle Field Corn Forage (R) 4 .0 40 10 1.00 Cotton Gin Byproducts (R) 15 90 5 0.83 Aspirated Grain Fractions (CC) 25 85 5 1.47 Beet Sugar Molasses (CC) 5 .0 75 10 0.67 Field Corn Grain (CC) 0.2 88 45 0.10 Rice Grain (CC) 1 .0 88 20 0.23 Soybean Seed (PC ) 2 .0 89 5 0.11 TOTAL 100 **4.41**

Poultry Field Corn Grain (CC) 0.2 NA 55 0.11 Rice Grain (CC) 1 .0 NA 20 0.20 Soybean Seed (PC) 2 .0 NA 20 0.40 Soybean Meal (PC) 2 .0 NA 5 0.1 0 TOTAL 100 **0.81**

Swine Field Corn Grain (CC) 0.2 NA 65 0.13 Rice Grain (CC) 1 .0 NA 20 0.20 Soybean Seed (PC ) 2 .0 NA 15 0.30 TOTAL 100 **0.63** NA = Not Applicable 1 As per Revised Table 1 (OPPTS Guideline 860.1000). 2 For beef and diary cattle: B urden = [Tolerance  % DM] x % D iet; for poultry and swine: Burden = Tolerance x % Diet / 100.Glufosinate Ammonium Summary of Analytical Chemistry and Residue Data D372625

Page 14 of 26 The dietary

burden calculated with the % of dry matter and % o f diet values from the updated T able 1 of OPPTS 860.0000 is shown in Table 5 . The previously calc ulated dietary

burden for beef cattle, dairy

cattle, poultry

and swine is 15.38, 15.22, 3.33 and 8.89 ppm, respectively (D271110, T. Bloem, 20/June/2002). These values are higher than the d ietary burden calculated fo r this new petition; therefore, current ly the tolerances for livestock are covered by the feeding studies previously

performed with diary

cow and poultry . **860.1500 Crop Field Trials** Reference DER s : 47915701 .der.doc , 47915702.der.doc, 47915703.der.doc, 47915704.der.doc, and 47915705.der.doc. Twenty three crop field trials were performed in the corresponding regions, according to OPPTS guidelines, to evaluate the magnitude of residue for orange, lemon and grapefruit . A summary of the residu e data is presented in Table 6 . Eight of the 23 tria ls used a non - ionic antifoam. Each trial consisted of one treated plot and one control plot. Following three broadcast applications of RELY at the target rate of 1.50 lb ai/A/application r esidues of glufosinate ammonium and its two metabolites, glufosinat e propanoic acid and N - acetylglufosinate were not detected above the LOQ (0.05 ppm) in/on oranges, lemons and grapefruit harvested at a PHIof 14 ( - 1) day s . No effect of the adjuvant on the residue levels was observed since the resid ues were below the method L OQ for applications with and without the non - ionic antifoam . Moreover , r esults from the residue decline study

performed on each of the three crop ty pes at five intervals corresponding to PHI s of 7, 11, 14, 17, and 21 day s indicated that residues of glufosinate ammonium , glufosinate propanoic acid and N - acetylglufosinate were below the LOQ at all PHI s used . For plum commodities , six crop field trials were performed according to OPPTS guidelines. For cherries, sweet cherries or tart cherries can be selected as a Stone Fruit crop group representative. The registrant submitted data with both crops and the regions were selected to represent both commodities. Five of the 12 trials for plum and cherries used a non - ionic antifoam. Each trial consisted of one treated plot and one control plot. Following three broadcast applications of RELY at the target rate of 1.50 lb ai/A/application r esidues of glufosinate ammonium and N acetylglufosinate in/on cherries and plum were not detect ed above the LOQ (0.05 ppm). However, 3 - methylphosphinico - propanoic aci d was at quantifiable levels in/on these commodities. One trial of the six field trials for cherries and for plum showed total residues above the LOQ. For cherries, the highest average field trial (HAFT) was 0.083 ppm with a maximum residue of 0.098 ppm. T he HAFT for total glufosinate ammonium residue was 0.183 ppm with a maximum residue of 0.198 ppm. For plums, the HAFT for 3 - methylphosphinico propanoic acid residue was 0.066 ppm with a maxi mum residue of 0.066 ppm. The HAFT for total glufosinate ammonium residue was 0.166 ppm with a maximum residue of 0.166 ppm. Any effect of the adjuvant (non - ionic antifoam) on the residue levels can not be established with this data; however, the t olerance for stone fruit commodities will be set based on the HAFT of the field trials with residues above the L OQ. Results from the residue decline study performed on both crop ty

pes at five intervals corresponding to PHI s of 7, 11, 14, 17, and 21 day s i ndicated that total glufosinate ammonium residues in cherry and plum were found to below or close to the LOQ at all PHI s ; therefore, a trend was not observed.Glufosinate Ammonium Summary of Analytical Chemistry and Residue Data D372625

Page 15 of 26 For peach, nine crop field trials were performed in the corresponding regions according to OPP TS guidelines. Each trial consisted of one treated plot and one control plot. No adjuvants were added to the herbicide mixture. Following two broadcast applications of RELY at the target rate of 1.50 lb ai/A/application there were no apparent residues o f glufosinate ammonium , 3 - methylphosphinico - propanoic acid and N - acetylglufosinate detected above the LOQ (0.05 ppm) in/on peach samples collected from the treated and untreated plots at a target PHI of 14 day s . There were no residue decline studi es perfo rmed for this commodity but were performed for other stone fruits, plum and cherry . For pear, six crop field trials were performed in the corresponding regions according to OPPTS guidelines. Each trial consisted of one treated plot and one control plot. Inall trials, ammonium sulfate was added to each tank mixture and applied at a rate of 3 lb/A. Two sites received a non ionic antifoam adjuvant. Following three broadcast applications of RELY at the target rate of 1.50 lb ai/A/application r esidues of g lufosinate ammonium and N - acetylglufosinate in/on pear were not detected above the LOQ (0.05 ppm). However, 3 - methylphosphinico - propanoic aci d was at quantifiable levels in one of the six field trials. Any effect of the adjuvant (non - ionic antifoam) on the residue levels can not be established with this data; however, the tolerance for Pome Fruit crop group will be set based on the HAFT of the field trials with residues above the LOQ. Results from the residue decline study with five sampling intervals corre sponding to PHI s of 7, 9, 14, 16, and 21 day s indicated that residues of glufosinate ammonium , glufosinate propanoic acid and N - acetylglufosinate were below the LOQ at all PHI s . For olives, three crop field trials were performed in the corresponding regi ons according to OPPTS guidelines. Each trial consisted of one treated plot and one control plot. In all trials, ammonium sulfate was added to each tank mixture and applied at a rate of 3 lb/A. I n two of the trials, a non - ionic antifoam was also added t o the tank mixture. Following three broadcast applications of RELY at the target rate of 1.50 lb ai/A/application there were no apparent residues of glufosinate ammonium , 3 - methylphosphinico - propanoic acid and N - acetylglufosinate detected above the LOQ (0 .05 ppm) in/on olive samples collected from the treated and untreated plots at the PHIof 14 day s. No effect of the adjuvant on the residue levels was observed since the residues were below the method L OQ for applications with and without the non - ionic antifoam . There were no residue decline studi es performed for this commodity . For sweet cor

n, twelve crop field trials were conducted in EPA region s 1, 3, 5, 10 and 11. T wo of the field trials in region five were performed in the same location at Arlingto n, Wisconsin; therefore , eleven field trials would represent the geographic diversity recommended by

HED. Each trial consisted of one treated plot and one control plot. In all trials at region 5, ammonium sulfate was added to each tank mixture. Stover w as dried for 5 to 13 day s after harvest. Follow ing two foliar applications of L iberty Herbicide at a rate of 0.375 lb ai/A for a total rate of 0.75 lb ai/A (one trial received an overapplication of 1.2 lb ai/A) with a retreatment interval (RTI ) of 14 - 1 6 day s and a PHIof 30 - 50 day s , HAFT residue values in/on s weet corn ears, forage and stover were 0.06, 0.74 and 3.55 ppm for the glufosinate acid equivalent from glufosinate ammonium and N - acetylglufosinate, 0.135, 0.14, and 0.49 ppm for glufosinate acid eq uivalent from glufosinate propanoic acid and 0.185, 0.79, and 3.72 ppm for total glufosinate acid, respectively . No residue decline data was collected.Glufosinate Ammonium Summary of Analytical Chemistry and Residue Data D372625

Page 16 of 26 **TABLE 6**  **. Sum ma**  **ry of Residue Data from Crop Field Trials with**  **Glufosinate am mo**  **nium and its Two**  **Met abolites**  **.** Commodity Total Applic. Rate

(lb ai/A) [kg ai/ha] PHI

(days) Residue Levels 1 (ppm)

n Min. Max. HAFT 2 Median Mean Std. Dev. **Glufosinate am monium**  Orange 4.38 to 4.61

[4.91 to 5.16] 14 24 <0.05 <0.05 <0.05 NA NA NA Lemon 4.50 to 4.53

[5.05 t o 5.07] 14 10 <0.05 <0.05 <0.05 NA NA NA Grapefruit 4.47 to 4.58

[5.01 to 5.14] 14 12 <0.05 <0.05 <0.05 NA NA NA Pear 4.45 to 4.57

[4.99 to 5.12] 14 12 <0.05 <0.05 <0.05 NA NA NA Cherry 3.00 to 3.11

[3.37 to 3.49] 14 12 <0.05 <0.05 <0.05 NA NA NA Plum 2.92 to 3.03

[3.27 to 3.40] 14 12 <0.05 <0.05 <0.05 NA NA NA Olive 4.50 to 4.52

[5.05 to 5.07] 14 12 <0.05 <0.05 <0.05 NA NA NA **Glufosinate propanoic acid** Orange 4.38 to 4.61

[4.91 to 5.16] 14 24 <0.05 <0.05 <0.05 NA NA NA Lemon 4.50 to 4.53

[5.05 to 5 .07] 14 10 <0.05 <0.05 <0.05 NA NA NA Grapefruit 4.47 to 4.58

[5.01 to 5.14] 14 12 <0.05 <0.05 <0.05 NA NA NA Pear 4.45 to 4.57

[4.99 to 5.12] 14 12 <0.05 0.089 0.081 0.05 0.05 3 0.0 07 Cherry 3.00 to 3.11

[3.37 to 3.49] 14 12 <0.05 0.098 0.083 0.05 0.056 0.013 Plum 2.92 to 3.03

[3.27 to 3.40] 14 12 <0.05 0.066 0.066 0.05 0.053 0.007 Olive 4.50 to 4.52

[5.05 to 5.07] 14 12 <0.05 <0.05 <0.05 NA NA NAGlufosinate Ammonium Summary of Analytical Chemistry and Residue Data D372625

Page 17 of 26 **TABLE 6 . Sum**  **ma ry of Residue Data from** **Crop Field Trials with Glufosinate am**  **mo nium** **and it s Two**  **Metabolites .**  Commodity Total Applic. Rate

(lb ai/A) [kg ai/ha] PHI

(days) Residue Levels 1 (ppm)

n Min. Max. HAFT 2 Median Mean Std. Dev. **N -**  **Acetylglufosinate** Orange 4.38 to 4.61

[4.91 to 5.16] 14 24 <0.05 <0.05 <0.05 NA NA NA Lemon 4.50 to 4.53

[5.05 to 5.07] 14 10 <0.05 <0.05 <0.05 NA NA NA Grapefruit 4.47 to 4.58

[5.01 to 5.14] 14 12 <0.05 <0.05 <0.05 NA NA NA Pear 4.45 to 4.57

[4.99 to 5.12] 14 12 <0.05 <0.05 <0.05 NA NA NA Cherry 3.00 to 3.11

[3.37 to 3.49] 14 12 <0.05 <0.05 <0.05 NA NA NA Plum 2.92 to 3.03

[3.27 to 3.40] 14 12 <0.05 <0.05 <0.05 NA NA NA Olive 4.50 to 4.52

[5.05 to 5.07]] 14 12 <0.05 <0.05 <0.05 NA NA NA **Total Glufosinate am**  **monium** Orange 4.38 to 4.61

[4.91 to 5.16] 14 24 <0. 1 5 <0. 1 5 <0. 1 5 NA NA NA Lemon 4.50 to 4.53

[ 5.05 to 5.07] 14 10 <0. 1 5 <0. 1 5 <0. 1 5 NA NA NA Grapefruit 4.47 to 4.58

[5.01 to 5.14] 14 12 <0. 1 5 <0. 1 5 <0. 1 5 NA NA NA Pear 4.45 to 4.57

[4.99 to 5.12] 14 12 <0.15 0.189 0.181 0.15 0.155 0.013 Cherry 3.00 to 3.11

[3.37 to 3.49] 14 12 <0. 1 5 0.198 0.183 0 .15 0.156 0.013 Plum 2.92 to 3.03

[3.27 to 3.40] 14 12 <0. 1 5 0.166 0.166 0.15 0.153 0.007 Olive 4.50 to 4.52

[5.05 to 5.07] 14 12 <0.15 <0.15 <0.15 NA NA NAGlufosinate Ammonium Summary of Analytical Chemistry and Residue Data D372625

Page 18 of 26 **TABLE 7**  **. Sum ma**  **ry of Residue Data from Crop Field Trials with**  **Glufosinate am mo**  **ni um in/on Sweet Corn**  Commodity Total Applic. Rate

(lb ai/A) PHI

(days) Residue Levels 1 (ppm)

n Min. Max. HAFT 2 Median Mean Std. Dev. **Glufosinate am monium**  **and N**  **- Acetylglufosinate**  Sweet Corn, Ears 0.75 30 - 50 24 <0.05 0.06 * 0.06 0.05 0.51 3 0.00 3 Sweet Corn, Forage 0.75 30 - 50 24 0.08 0. 74* 0.74 0.19 0.32 0.23 Sweet Corn, Stover 0.75 30 - 50 24 0.33 3.55* 3.55 1.12 1.20 1.12 **Glufosinate propanoic acid** Sweet Corn, Ears 0.75 30 - 50 24 <0.05 0.1 35* 0.135 0.05 0.06 0.03 Sweet Corn, Forage 0.75 30 - 50 24 <0.05 0.1 4* 0.14 0.05 0.06 0.03 Sweet Corn, Stover 0.75 30 - 50 24 <0.05 0. 49* 0.49 0.09 0.12 0.09 **Total Glufosinate** Sweet Corn, Ears 0.75 30 - 50 24 0.10* 0.19* 0.19* 0.10 0.11 0.02 Sweet Corn, Forage 0.75 30 - 50 24 0.18* 0.79* 0.79* 0.28 0.44 0.23 Sweet Corn, Stover 0.75 30 - 50 24 0.16* 3.7* 3.7* 1.43 1.16 1.05 *T he average residue of each analyte in each field trial were added and the total residue value of each trial was used to select the max imum and minimum values . In a similar way the HAFT was selected f rom the sum of the average values of each analyte from each field trial. In the study provided , the residues from each field trial we re reported in pairs; therefore, is not possible to identify the residue from each one of the duplicate sample s analyzed i n each field trial . Conclusions . The number and location of field trials for orange, lemon, grapefruit, pear, cherry , plum and olive comply

with the requireme nts of OPPTS 860.1500 guideline . The data are adequate to establish t olerances for these RACs . The residue decline studies in all the commodities tested showed that residues were below or close (for plum) to the LOQ at all PHI s; therefore, residues are not expected to be higher at longer PHI s than those established for the RACs under this petitio n. **860.1520 Processed Food and Feed** Processing studies were performed for orange, plum and olive commodities. Detailed reviews concerning the processing studies submitted in support of the current petitions can be found in the following reviews: orang e ( 47915706 .der.wpd) , plum (47915707.der.wpd) and olive ( 47915708 .der.wpd) . A summary of the results obtained is summarized in Table 8 . Orange s w ere treated with three applications of RELY herbic ide at 7.5 lbs ai/A ( 14 - day RTI ; 22.73 lbs ai/A total; 5 x the maximum proposed seasonal application rate ). Oranges were harvested 14 day s after the last application and processed into dried pulp, oil, juice (pasteurized), peels, and peeled fruit . However, only the orange RAC and orange oil (the processed commodi tyGlufosinate Ammonium Summary of Analytical Chemistry and Residue Data D372625

Page 19 of 26 with the highest theoretical processing factor) were analy zed for residues of glufosinate ammonium , N - acetyl - glufosinate and glufosinate propanoic acid . After using exaggerated rates, the residues in the orange RAC were below the method L OQ . Under thi s condition tolerances and processing studies are not required with the exception of those for commodities with very high processing factors, citrus oil (1000x) and mint oil (330x). The orange oil processed commodity

resulted in combined residues of glufo sinate ammonium , N - ac etyl - glufosinate and glufosinate propanoic acid below the method L OQ; therefore, these didn’t concentrated in orange oil (1x). Orange juice and orange dried pulp were prepared by the registrant but not analy zed. Based on the guidelin es, the analy sis of these processed commodities is not required when the residues are below LOQ in the RAC after applying 5x exaggerated rates. Plum s w ere treated with two applications of RELY herbicide at 7.5 lbs ai/A (28 - day RTI ; 15 lbs ai/A total; 5x the maximum proposed seasonal application rate). Plums were harvested 14 days after the last application and processed into prunes. Plums and prunes were analy zed for residues of glufosinate ammonium, N - acetyl - glufosinate and glufosinate propanoic acid . Only residue levels of glufosinate propanoic acid were above the method LOQ in the plums and prunes samples. The total average residue level in the prune samples was 0.433 ppm. After correction for the exaggerated application rate (5x) the residue leve l (0.0866 ppm) will be below the method total L OQ (0.15 ppm); therefore, no tolerance is required for the prune RAC. However, a processing factor of 1.8x can be set for the prunes RAC by assuming that glufosinate ammonium, N - acetyl - glufosinate and glufosi nate propanoic acid are at LOQ levels when these were not detected. This processing factor is below the theoretical concentration factor of 3.4x which is based on loss of water. Olives were treated with three applications of RELY herbicide at 7.5 lbs a i/A (14 - day RTI ; 22.5 lbs ai/A total; 5x the maximum proposed seasonal application rate). Olives were harvested 14 day s after the last application and processed into olive oil. Samples of olives and olive oil were analy zed for residues of glufosinate amm onium, N - acetyl - glufosinate and glufosinate propanoic acid . Only

residue levels of glufosinate propanoic acid were above the method LOQ in the olive samples. The total average residue level in the olive oil sample was below the method L OQ; therefore, no tolerance is required for the olives RAC. However, a processing factor of 0.6x can be set for the olives by

assuming that glufosinate ammonium, N - acetyl - glufosinate and glufosinate propanoic acid are at LOQ levels when these were not detected . T his proc essing factor is below the theoretical concentration factor of 108x which is based on separation of components. The orange, prunes and olive oil processing studies will be considered adequate at this time but for future studies the registrant is recomme nded to analy ze the washed RAC if this is washed during the processing studies. The current practice of using the unwashed RAC residue levels may result in a sub estimation of the processing factor.Glufosinate Ammonium Summary of Analytical Chemistry and Residue Data D372625

Page 20 of 26 **TABLE 8**  **. Residue Data from** **Orange, Plum and Olive**  **Proce ssing Study with Glufosinate**  **Am mo**  **nium .**  Trial: City, State; Year (Trial ID#) Processed

Commodity Total

Rate (lb ai/A) PHI (days) Glufosinate

ammonium Glu - NAG Glu - PPA Total 3 Residues (ppm) 1 Processing

Factor2 Residues

(ppm) 1 Processing

Factor2 Residu es

(ppm) 1 Processing

Factor2 Residues

(ppm) 1 Processing

Factor2 Arroyo Grande, CA; 2008 (GL001 - 08PA) Orange,

Fruit 22.73 14 <LOD -- <LOD -- <LOD -- <0.15 -- Orange, Oil <LOD ≤1x <LOD ≤1x <LOD ≤1x <0.15 ≤1x Live Oak, CA; 2008 (GL025 - 08PA) Plum RAC

(unwashed) 15.0 14 0.0704, <LOQ (0.0229), <LOD Avg. <LOQ -- 0.142,

0.126, 0.131 Avg. 0.13 -- <LOQ

(0.0358), <LOD, <LOD Avg. <LOQ -- 0.262

0.226 0.231 Avg. 0.240 --

Prune <LOD, <LOD, <LOD Avg. <LOD <1.0X 0.393,

0.344, 0.263 Avg. 0.33 2.5X <LOD,

<LOD, <LOD Avg. <LOD <1.0X 0.493

0.444 0.363 Avg. 0.433 1.8X

Corning, CA; 2008 (GL047 - 08PA) Olive RAC 22.5 14 <LOD, <LOD, <LOD Avg. <LOD -- 0.132,

0.142, 0.134 Avg. 0 .136 -- <LOD,

<LOD, <LOD Avg. <LOD -- 0.232

0.242 0.234 Avg. 0.236 --

Olive Oil <LOD, <LOD, <LOD Avg. <LOD <1.0x <LOD,

<LOD, <LOD Avg. <LOD <0.2x <LOD,

<LOD, <LOD Avg. <LOD <1.0x <LOD,

<LOD, <LOD Avg. <LOD <0.6x

1 LOQ = 0.05 ppm for glufosinat e ammonium , Glu - PPA and Glu - NAG. Residues in parenthesis are values between the LOD and LOQ. 2 The processing factor was calculated by dividing the residues in the processed sample by the residues in the unprocessed RAC sample. Values <LOQ and <LOD wer e assigned a value of the LOQ (0.05 ppm) for calculations. 3 The total glufosinate ammonium residue is the sum of the individual measured residue for the analytes of glufosinate ammonium, Glu - NAG and Glu - PPA . Values <LOQ and <LOD were assigned a value of the LOQ (0.05 ppm) for calculations. Conclusions: The process ed commodities required under OPPTS 860.1520 guidelines for the corresponding RACs were prepared and analy zed . These studies are considered acceptable. However, the petitioner is advised to w ash the RAC before analy sis if it will be washed during processing. **860.1850 / 860.1900 Confined / Field Accumulation in Ro**  **t ational Crops**  D271110, T. Bloem, 20/June/2002 A confined rotational crop study has been submitted and reviewed (D211531 and D219 069, M. Rodriquez, 7 - Mar - 1996). L ettuce, radish, and spring wheat were planted 28 and 119 days afterGlufosinate Ammonium Summary of Analytical Chemistry and Residue Data D372625

Page 21 of 26 the soil was treated with [3,4 - 14 C] - HOE - 039866 at 0.9 lbs ai/acre (1.2x the maximum proposed application rate for sweet corn). All samples planted 28 days after treatment were analy zed. HOE 061517 (5 - 57% TRR) and HOE 064619 (6 - 10% TRR) were the only compounds identified (a total of 32 - 64% of the TRR was identified). Except for the wheat commodities, TRRs were  0.02 ppm for the samples planted 120 day s af ter treatment (wheat commodities 0.06 - 0.15 ppm). A wheat field rotational crop study has also been submitted and reviewed (P. Errico [RD], 6 - May- 1998). Wheat was planted 73 - 90 day s after the soil was treated with glufosinate ammonium at 0.8 lbs ai/acr e (1.2x the maximum proposed application rate for sweet corn). Wheat forage, hay , straw, and grain were harvested at maturity and analy

zed for residues of glufosinate ammonium and HOE 061517 (residues were < L OQ; L OQ = 0.05 ppm). Based on the conf

ined and field rotational crop studies, the MARC determined that the residues of concern in rotational crops, for tolerance expression and risk assessment purposes, are glufosinate ammonium, HOE 061517, and HOE 064619 (D282757, T. Bloem, 9 - May- 2002). The Li berty

Herbicide label indicates that plant rotation to other crops after treatment of sweet corn can occur with a Plant Back Interval (PBI ) of 120 day s with the exception of wheat, barely , buckwheat, millet, oats, rye sorghum, and triticale for which a P BI of 70 day s is allowed. Based on the results from the confined and field rotational studies, HED concludes that the proposed rotational crop restrictions are appropriate for sweet corn. **860.1650 Submittal of Analytical Referenc e Standards**  Analy tical standard s for the herbicide glufosinate ammonium, N - acetylglufosinate and 3 - methylphosphinico - propanoic acid are to be kept available in the EPA National Pesticide Standards Repository . These analy tical reference standards must be replenished as requested by the Repository . I f requested, r eference standards should be sent to the Analy tical Chemistry Laboratory

located in Fort Meade to the attention of either Theresa Cole at the following address: U.S. EPA National Pesticide Standards Repository / Analy tical Chemistry

Branch/OPP 701 Mapes Road Fort George G. Meade, MD 20755 - 5350 Please note that mail will be returned if the entire extended zip code is not used when addressing correspondence to the Repository . **860.1550 Propos ed Tolerances**  Glufosinate ammonium tolerances are established under 40 CFR §180. 473 and are currently expressed in terms of glufosinate ammonium and two of its metabolites . On 27 - MAY - 2009 HED established interim guidance on writing tolerance expressions for enforcement purposes. In order to add clarity

to the language used to establish the coverage of the tolerance expression and measurement of the level of the residue in the RACs the text in the 40 CFR § 180.533 shouldGlufosinate Ammonium Summary of Analytical Chemistry and Residue Data D372625

Page 22 of 26 read: “(a) General. (1) Tolerances are establ ished for residues of glufosinate ammonium , 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 gluf osinate ammonium (butanoic acid, 2 - amino - 4 - (hydroxy methylphosphinyl) - monoammonium salt) and its metabolites, 2 - acetamido - 4 - methylphosphinico - butanoic acid and glufosinate propanoic acid , expressed as 2 - amino - 4 - (hydroxy methylphosphinyl)butanoic acid equival ents .” The residue values obtained in the A summary of the recommended tolerances for the crop commodities discussed in this Summary Document is presented in Table 9 . **Table 9**  **. Tolerance Sum ma**  **ry for Glufosinate Am**  **mo nium**  **.** Commodity Current §180.533 Tol erance (ppm) Proposed

Tolerance (ppm) Recommended §180.533

Tolerance (ppm) Comments Citrus (CG 10) None 0.05 0.1 5 Fruit, citrus, group 10 * Pom e Fruit (CG 11) None 0.10 0. 25 Fruit, pome, group 11 * Stone Fruit (CG 12) None 0.10 0. 25 Fruit, stone, group 1 2 Olives None 0.05 0.1 5 Corn, sweet, kernels plus cob with husks removed None 0.2 0. 25 Corn, sweet, f

orage None 4.0 1.6 Corn, sweet, s tover None 6.0 10 Plum, p rune , dried None 0.20 N/A Covered by the Stone Fruit tolerance. * Or Group 10 - 10 and Gr oup 11 - 10 w hen these new crop groups are officially established. The NAFTA calculator was used to establish the tolerance for sweet corn forage and stover. The maximum residues from each field trial location were selected from each analy te and then summe d to obtain the total residue value used to establish the tolerance. A lognormal distribution was assumed and the 95/99 rule was used to calculate the tolerance for sweet corn forage and the UPL median 95 method for sweet corn stover. The latter method i s used as an alternative to the 95/99 rule when the standard deviation of the field trials is high. For the remaining commodities the tolerance was estimated based on the HAFT. The Codex Alimentarius Commission has not established maximum residue l imit s (MRL s) for glufosinate ammonium in/on olives and sweet corn commodities . However, for glufosinate ammonium in/on Citrus, Pome Fruit and Stone Fruit the Codex have set a MRLof 0.1, 0.05, and 0.05 ppm , respectively . T he US tolerance for Citrus, Pome Fru it and Stone Fruit , is 0.15, 0.25 and 0.25 ppm , respectively . The US tolerance values for these commodities is higher than the Codex MRL ; therefore, harmonization of the US tolerances with the Codex MRL s is not possible with this petition , see Attachment 1 . There are no MRLs established in Mexico or Canada for the use of glufosinate ammonium on the commodities under the current petition.Glufosinate Ammonium Summary of Analytical Chemistry and Residue Data D372625

Page 23 of 26 **References** T om Bloem, Glufosinate Ammonium (PC Code: 128850). L abel Amendment for Pre - Plant Application of Glufosi nate Ammonium to Transgenic and Non - transgenic Field Corn, Non transgenic Canola, and Non - transgenic Soy bean. Residue Chemistry

Summary ., D335330, 09/12/2007 . Tom Bloem, Glufosinate Ammonium (PC Code 128850). Section 3 Registrations for Transgenic Cotton (ID# - 0F06140), Transgenic Rice (ID# - 0F06210), and Bushberry (ID# - 2E06404). Summary of Analy tical Chemistry

and Residue Data., D271110, 20/June/2002. M. Rodriguez , PP5G4466 & PP5F4578: Glufosinate - ammonium in/on Transgenic Corn and Soy beans. Experime ntal Use Permit, Temporary Tolerance and Permanent Tolerance Petitions. Evaluation of Analy

tical Method and Residue Data., D219069 and D211531, 03/07/1996. **Attachments** Attachment 1: International Residue L imit Status Attachment 2 : NAFTA Calculator ResultsGlufosinate Ammonium Summary of Analytical Chemistry and Residue Data D372625

Page 24 of 26 **Attachment 1**  **: International Residue Limit Status**



### Glufosinate Ammonium (PC Code 128850; Aug 10, 2010) Summary of US and International Tolerances and Maximum Residue Limits Residue Definition : US Canada Mexico 2 Codex 3 40 CFR 180.473 Plant and Livestock: glufosinate ammonium (butanoic acid, 2 - amino - 4 - (hydroxy methylphosphinyl) - monoammonium salt) and its metabolites, 2 - acetamido - 4 - methylphosphinico butanoic acid and 3 - methylphosphinico propionic acid, expressed as 2 - amino - 4 - (hydroxy methylphosphinyl)butanoic acid equivalents ammonium(±) - 2 - amino - 4 - (hydroxy methylp hosphinyl)butano ate, including the metabolite propanoic acid, 3 - (hydroxy methylp hosphinyl) Sum of glufosinate ammonium, 3 - [hydroxy(methyl)ph osphinoyl]propionic acid and N - acetyl glufosinate, calculated as glufosinate (free acid). Commodity 1 Tolerance (ppm) /Maximum Residue Limit (mg/kg) US Canada Mexico 2 Codex Citrus (CG10) 0.15* Citrus fruits 0.1 Pom e Fruit (CG 11) 0. 25 Pom e fruits 0.05 (*) Stone Fruit (CG 1 2) 0. 25 Stone fruits 0.05 ( *) Olives 0.1 5* Corn, Sweet, Ears 0.25 Corn, Sweet, Forage 1.6 Corn, Sweet, Stover 10 Completed: M. Negussie; 08/10/2010 1 Includes only commodities of interest for this action. Tole rance values should be the HED recommendations and not those proposed by the applicant. 2 Mexico adopts US tolerances and/or Codex MRLs for its export purposes. 3 * = absent at the limit of quantitation; Po = postharvest treatment, such as treatment of stored grains. PoP = processed postharvest treated commodity, such as processing of treated stored wheat. (fat) = to be measured on the fat portion of the sample. MRLs indicated as proposed have not been finalized by the CCPR and the CAC.Glufosinate Ammonium Summary of Analytical Chemistry and Residue Data D372625

Page 25 of 26 **Attachment 2 .1**  **: NAFTA Calculator Results for Sweet Corn Forage**  **Reg ulat**  **or:** EP A **Ch emic**  **al:** Gl ufos inate **Cr op:**  Sw eet Corn, For age **PH I:**  43 Day s **App . Ra**  **te:** 0. 75 l b ai/ A **Sub mitt**  **er:** IR -4

**n:** 12 **mi n:**  0.1 0 **ma x:**  0.9 8 **medi an:**  0.3 4 **av era**  **ge:** 0.4 3 **95th Per**  **centi le**  **99 th P**  **erce ntile**  **99.9 th Pe**  **rcen tile**  0. 90 1.1 1. 3 (1. 2) (1 .5) (--) 1. 1 **1.6** 3. 0 **(2. 5)**  (4 .0) (--) #R EF! **1.3 2.5**  0.96 41 p- valu e > 0.05 : Do not reje ct l ogno rmali ty a ssump tion **Appr oxima**  **te Sh**  **apir o-Fra**  **ncia Norm**  **alit y Tes**  **t EU M**  **ethod I**  **Norm al** 

**UC LMe**  **dian9 5th**  **95 /99**  **Rule EU**  **Meth od II**  **Dis trib**  **ution -Fre**  **e Me**  **an+ 3SD** 

**Lognormal Probability Plot**

99.9 99 98 95 90 80 70 50 30 20 10 5 2 1 0.1 1.0000

0.5000

0.2500

0.1250

0.0625 y = 0.6651x - 1.0315 R 2 = 0.9641

**Percentiles C** **o n** **c e** **n t** **r a** **t i** **o n** **s EPA Glufosinate Sweet Corn, Forage 43 Days 0.75 lb ai/A IR-4** Glufosinate Ammonium Summary of Analytical Chemistry and Residue Data D372625

Page 26 of 26 **Attachment 2.2: NAFTA Calculator Results for Sweet Corn Stover**  **Reg ulat**  **or:** EP A **Ch emic**  **al:** Gl ufos inate **Cr op:**  Sw eet Corn, Sto ver **PH I:**  43 Day s **App . Ra**  **te:** 0. 75 l b ai/ A **Sub mitt**  **er:** IR -4

**n:** 12 **mi n:**  0.1 9 **ma x:**  5.5 4 **medi an:**  1.6 1 **av era**  **ge:** 1.5 7 **95th Per**  **centi le**  **99 th P**  **erce ntile**  **99.9 th Pe**  **rcen tile**  4. 0 5.0 7. 0 (6. 0) (8 .0) (--) 6. 0 **13** 30 **(1 9)**  (55 ) (--) #R EF! **6.0 10**  0.91 37 p- valu e > 0.05 : Do not reje ct l ogno rmali ty a ssump tion **Appr oxima**  **te Sh**  **apir o-Fra**  **ncia Norm**  **alit y Tes**  **t EU M**  **ethod I**  **Norm al** 

**UC LMe**  **dian9 5th**  **95 /99**  **Rule EU**  **Meth od II**  **Dis trib**  **ution -Fre**  **e Me**  **an+ 3SD** 

**Lognormal Probability Plot**

99.9 99 98 95 90 80 70 50 30 20 10 5 2 1 0.1 6.0000

3.0000

1.5000

0.7500

0.3750

0.1875 y = 1.0734x + 0.012 R 2 = 0.9137

**Percentiles C** **o n** **c e** **n t** **r a** **t i** **o n** **s EPA Glufosinate Sweet Corn, Stover 43 Days 0.75 lb ai/A IR-4**