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**EPA REGISTRATION DIVISION COMPANY NOTICE OF FILING FOR PESTICIDE PETITIONS PUBLISHED IN THE FEDERAL REGISTER**  **EPA Registration**  **Division contact: Kathryn Montague**  **, 703 -**  **30 5**  **- 1243**  Sy ngenta Crop Protection, LLC PP# [ 2E8098 ] EPA has received a pesticide petition PP# ( [ 2E8098 ] ) from Sy ngenta Crop Protection , LLC, P.O. Box 18300, Greensboro, NC 27419

- 8300 request ing, 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 1. by establishing an import tolerance for residues of Bicy clop yrone : 4

- hy droxy

- 3

- {2

- [(2

- methoxy ethoxy )meth yl }

- 6

- (trifluoromethyl)

- 3

- py rid yl carbon yl }bicy clo[3.2.1]oct

- 3

- en - 2

- one , in or o n the raw agricultural commodities: sugarcane, stalks at 0.01 parts per million (ppm)

. EPA has determined that the petition contains data or information regarding the elements set forth in section 408 (d ) ( 2) of FDDCA; however, EPA has not full y evaluated the sufficiency

of the submitted data at this time o r whether the data supports granting of the petition. Additional data may be needed before EPA rules on the petition. A. Residue Chemistry 1. Plant metabolism. Sy ngenta believes the studies supporting this bicyclopy rone petition well characterize metabolism in plants. The metabolism profile supports the use of an anal yt ical enforcement method that accounts for parent bicy clop yr one. The metabolism and distribution of NOA449280 has been investigated in corn and sugarcane. For this study , NOA449280 radiolabelled with 14 C in either the py ridine or the bicy clooctenone ring was used

. The uptake, distribution and degradation of NOA449280 were investigated in sugarcane b y a single treatment at a nominal rate of 300 g ai /ha post emergence to the cane at the 7

- 8 leaf stage (BBCH 17

- 18). Foliage samples were taken 42 day s after treatment (BBCH 23

- 24) to facilitate determination of the biotransformation pathway . Foliage (all leaves) and cane were collected at maturit y, 301 days aft er treatment (BBCH 39). The total radioactive residues (TRR) of the harvested commodities and the percentages of the TRR (%TRR) are summarized below.2

**Radiolabelled experiment**  **Relative Maturity Sample/**  **Comm odity**  **TRR**

**mg/kg % TRR** 

**Extracted 1**  Bicycloocetenone 42 DAT Foliage 0.778 85.4

Maturity (301 DAT) Foliage 0.004 Not extracted 2 Sugarcane 0.002 Not extracted 2 Py ridine 42 DAT Foliage 0.888 88.5

Maturity (301 DAT) Foliage 0.003 Not extracted 2 Sugarcane 0.004 Not extracted 2 1 Extractable radioactivity prior to aqueous extraction and hydrolysis 2 The maturity samples were not extracted or analyzed since the TRR was < 0.01 mg/kg Due to the low residues of the mature samples, the 42 DAT samples for both radiolabels were used to el ucidate the biotransformation of NOA449280 in sugarcane. Analy sis of these samples shows an absence of parent NOA449280 and that extensive metabolism has occurred with the principle biotransformations as follows:

 h y dr o xyl at i o n o f t h e b i c yc loo c t e no n e r in g in at l e a s t t w o p o s i t i o ns to p ro duce i s o me r s o f mo n o h y

dr o xy l at ed and d ih y

dr o x y l at ed NOA449280

 c l e a vage be t ween t h e b i c yc loo c t e no n e and p y r i d in e r in g s ys t e m s o f NOA449280

 O

- d e me t hyl at i o n , and s ucc e s s ive o x i dat i o n o f t h e m e t h o x y e t h o xy m e t hyl s i de c h a in o f NOA449280 t o p ro duce de s me t hyl , carb o xyl a nd a l c o h o l m e t a b o l i t e s

 c o n j ug at i o n o f s o me o f t h e ab o v e me t a b o l i te s t o f o r m t h e i r O

- g l y c o s i d es The largest percentage of the residue contained metabolites where the bicyclooctenone ring of NOA449280 had undergone mono

- hy droxylation or mono

- hy drox ylation and O

demethylation of the methoxyethox ym eth yl side chain. These combined metabolites accounted for 50

- 55% of the TRR. Di

- hy drox yl ation of the bicy clooctenone ring coupled with de meththylation of the side chain was present to a lesser extent. Cleavage between the rings also made a significant contribution to the residue b y the presence of CSCD686480 which is the py ridine specific metabolite formed by cleavage of NOA449280. The re sults are summarized below: **Bicyclooctenone**  

** 14** **C Pyridine**  **- 14**  **C Sugarcane**  **Sample Component**  **% of TRR**  **Residue**

**(m g/kg)**  **% of**

**TRR Residue**  **(m g/kg)** 

42 DAT Foliage CSCD686480 1 ND ND 19.7 0.175

CSCD686481 ND ND 6.4 0.057 CSCD677692 5.5 0.043 6.5 0.058 Total desmethyl monohydroxy NOA449280 isomers 1 37.1 0.289 33.9 0.301 Total monohydroxy NOA449280 isomers 1 25.8 0.201 20.7 0.184 ND = not detected , 1 Total of all isomers with these structural characteristics including specific metabolites, metabolites of undefined substitution specificity, and conjugates3 Metabolism studies conducted in corn and sugarcane have provided a detailed understanding of the biotransformation of NOA449280 in these crops. The metabolic pathways in these crops are similar. NOA449 280 was found only in corn forage and was absent in all other samples examined. The majority of the metabolites were formed by hydroxylation on one or more sites on the bicyclic ring or demethylation of the methoxyethoxymethyl side chain followed by hydro xylation. Some conjugation to glycosides was observed with the hydroxyl derivatives and some cleavage between the two ring systems was also observed. 2. Analytical method. For data submitted with this petition , the following analytical methods were utili zed:

**Me thod Identification**  **Analyte Limit of Quantification (ppm)**  **In Sugarcane Stalks** POPIT MET.116 (based on GRM030.03A) NOA449280 (Parent) 0.01 SYN503780 0.01 POPT MET.117 (based on GRM030.05A 1 ) Common Moiety SYN503780 0.01 Common Moiety CSCD686480 0.01 CSAA806573 0.01 POPIT MET.114 Ametryn 0.01 1 Analysis covers parent and all other structures similar to parent. The analytical methods are available for enforcement purposes with limits of detection that allows monitoring of food with residues at or above the levels set in these tolerances. Residues of NOA449280 and SYN503780 were by two different methods, direct analysis and common moiety method. Additionally, residues of CSAA915194, CSCD686480 and CSAA806573 were also determined. CSAA806573 and ametryn were analysed via a direct method. CSAA915194 was analysed by a common moiety method. A method validation was conducted in the laboratory via recoveries of samples fortified with the compounds being quantified in the study. The overall confidence intervals of recovery means at a 95% confidence level for NOA449280 and its metabolites were as follows: NOA449280 ( POPIT MET 116) was 108±1, SYN503780 (POPIT MET 116) was 107±1 , NOA449280 (POPIT MET 117) was 75 + 3 to 82 ±3, CSAA915194 (POPIT MET 117) was 93±5, CSAA806573 (POPIT MET 117) was 87±5 to 95 + 5 and ametryn (POPIT MET 114) was 84±7. These data indicate acceptab le performance of the methods used to support this study. The LOQ for all analytes in all sample matrices, including processed fractions, was 0.01 ppm. The mean recoveries were all between 70 and 120% for all analytes using both methods. The percent re lative standard deviations (%RSD) were all ≤ 20%. These data indicate acceptable performance by the two methods used to support this study. Analy tical methods GRM030.03A and GRM030.05A have also undergone independent laboratory

validation (ILV) to demonstrate the suitability of the methods for the monitoring of residues of NOA449280 in crops and animal tissues. All study methods and validation reports will be submitted with this data package. 3

. Magnitude of residues. A residue stud y was conduc ted to support the4 registration of NOA449280 on sugarcane in Australia and an import tolerance in the US

. Studies were also conducted in Brazil and are included herein as additional support for import tolerances for the United States. The maximum lab el rate per year will be 300 g ai /ha. The number of allowed applications will be up to 2 applications /y ear but not exceeding 300 g ai /ha. The product will be applied pre

- emergent to cane and weeds and/or earl y post emergent to cane and weeds (as a directed s pray) up to the out

- of

- hand stage of sugarcane . Shortest interval between applications would be 4 weeks. The proposed PHI or harvest withholding period is “not required when used as directed” since the interval between the last possible application (out

- o f

- hand stage or prior to row closure as indicated in the residue report) and harvest is very long (at least 112 day s). **AUSTRALIA** Eight crop residue trials were conducted with NOA449280 in 2009 and 2010 in Australia. **Site Number Location**  **Treatm ent**  1 Tw eed Valley, New South Wales Split Application (Ratoon crop

– no trash) 2 Proserpine, Queensland Split Application 3 El Arish, Queensland Split Application 4 Mareeba, Queensland Split Application 5 Gunalda, Queensland Single Application 6 Garget, Queensland Single Application 7 McDesme, Queensland Single Application (Ratoon crop

– no trash) 8 Gordonvale, Queensland Single Application Formulation A16003E, a soluble concentrate (SL), containing 200 g/kg NOA449280 was applied to the sugarcane. Application scenarios are presented below . A non

- ionic surfactant (NI S) was included in each of the spray applications.

**Sites Treatm**  **ent Nom**  **inal Application Rate (g ai/ha)**  **Nom inal Application Timings** 
1, 2, 3, and 4 (Split Application) 1 (Control)

-- Not Applicable 2 App 1: 150

App 2: 150 App 1: 4 w eeks prior to Timing 2 (approx. 60

- 80

cm) App 2: Just before row

closer (out of hand stage) 3 App 1: 300

App 2: 300 App 1: 4 w eeks prior to Timing 2 (approx. 60

- 80

cm) App 2: Just before row

closer (out of hand stage) 5, 6, 7, and 8 (Single Application) 1 (Control)

-- Not Applicable 2 300 Just before row closer (out of hand stage) 3 600 Just before row closer (out of hand stage)5 In the split application trials, sugarcane billets and tops were collected immediately

before the last application, immediately after the last application and at nominal timings of 7, 16, 28, 56 and 112 day s after last application (DALA). For the single application trials, samples were collected at 0, 7, 14, 18, 56 and 112 DALA. No residues of NOA449280 (parent), SYN503780, the common moiety SYN503780, the common moiety CSCD686480 or CSAA589691 were found in any untreated control samples of any sugarcane billets or tops in this study (all <LOQ). In the treated samples, the residues decrease quickl y with increasing time between spray

and harvest, i.e. 1 day

after application to 28 day s after applicati on. No residues at or above the LOQ were found at harvest (112 DAA). **BRAZIL** Five crop residue trials were performed across Brazil in Itápolis (SP), Rio das Pedras (SP), Bandeirantes (PR), Jaboticabal (SP) and in Uberlândia (MG)

. Formulation A16003E, a soluble concentrate (SL), containing 200 g/kg NOA449280 was applied to the sugarcane. A non

- ionic surfactant (NIS) was included in the post

- emergent application. **Treatm ent**  **Nom inal Application Rate**  **Nom inal Application Timings**  1 (Control)

-- Not Applicable 2 300 g ai /ha

(1.5 L product /ha) Pre
- em ergence, soon after the crop w as cut and cultivated BBCH 00 3 300 g ai /ha

(1.5 L product /ha) Post
- em ergence, when the sugarcane plants already had 5 leaves BBCH 15

- 16 Sugarcane stalks were sampled at normal harvest. No residues of NOA449280 or any of its other metabolites were found in any of the mature sugarcane stalks samples after the treatment of plots with 300 g as NOA449280 /ha (1.5 L product/ha) either pre

- emergent (BBCH 00) or post

- emergent (BBCH 15

- 16). Four crop residue trials were performed across Brazil in the cities of Rio das Pedras (SP), Bandeirantes (PR), Jaboti cabal (SP) and Tupaciguara (MG). Formulation A16361B, a soluble concentrate (SL) containing 57 g/L NOA449280 and 434 g/L of ametry

n, was applied to the sugarcane. A non

- ionic surfactant (NI S) was included in the post

- emergent application. **Treatm ent**  **Application Rate Nom**  **inal Application Timings** 1 (Control)

-- Not Applicable 2 286 g NOA449280/ha + 2143 g am etryn/ha (5.0 L product /ha) Pre
- em ergence, soon after the crop w as cut and cultivated BBCH 00 3 171 g NOA449280/ha + 1286 g am etryn/ha (3.0 L product /ha) Post
- em ergence, when sugarcane plants already had 5 leaves BBCH 15

- 166 Sugarcane stalks were sampled at normal harvest. When A16361 was applied at the maximum intended use rates for both pre

- emergence and post

- emergence, there was no quantifiable residues of the anal ys ed compounds in samples of sugarcane collected at normal harvest time. In Brazil, two crop residue trials were performed at exaggerated rates in Carpina (PE) and Ares (RN) to generate samples for processing into sugar, molasses and bagasse

. Formulation A16003E, a soluble concentrate (SL), containing 200 g/kg NOA449280 was applied to the sugarcane. Tre atment scenarios included pre

emergent application soon after the crop was cut at 900 h ai/ha (3X label rate) and at 1500 g ai/ha (5X label rate). **Treatm ent**  **Nom inal Application Rate**  **Nom inal Application Timings**  1 (Control)

-- Not Applicable 2 900 g ai /ha

(4.5 L product /ha) Pre
- em ergence, soon after the crop w as cut and cultivated BBCH 00 3 1500 g ai/ha

(7.5 L product /ha) Pre
- em ergence, soon after the crop w as cut and cultivated BBCH 00 Sugarcane stalks were sampled at normal harvest. No residues of NOA449280 or any of its other metabolites were found in any of the mature sugarcane stalks samples after the pre

- emergent (BBCH 00) treatment of plots with exaggerated rate applications of 900 g ai NOA449280 /ha (4.5 L product/ha) or 1500 g ai/ha NOA449280 (7.5 L product/ha). **CONCLUSIONS** NOA449280 is intended for use as an herbicide on sugarcane in Australia and proposed for an import tolerance for the US

. Supporting f ield residue data from Australia and Brazil are being submitted with this data package. The data indicate that when NOA449280 is applied at a rate of 300 g ai/ha) either pre

emergent (BBCH 00) or post

- emergent (BBCH 14

- 16), no quantifiable residues will result in raw agricultural sugarcane commodities (billets, tops, stalk s).
B. Toxicological Profile **1.** Acute toxicity

. NOA449280 is of low acute toxicity by the oral, dermal and inhalation routes of exposure and is not irritating to the ey es or skin. Under conditions of a local l ymph node assay in the mouse NOA449280 is not considered to have a sensitising potential follo wing contact with the skin. NOA449280 SL(A16003E) is of low acute toxicity by the oral, dermal and inhalation routes. It is not irritating to the skin and only slightl y irritating to the ey e. It is a sensitizer in the Buehler test in the guinea pig. NOA4 49280 ZC (A19707A) is of low acute toxicity by the oral, dermal and inhalation routes.7 It is moderatel y irritating to the skin and to the eye. It is a sensitizer in the Buehler test in the guinea pig. A summary of the acute toxicity

studies are cited belo w:

**Hazard Indicator (Guideline No.)**  **Bicyclopyrone**

**Technical (NOA449280)**  **SYNA16003 (SL)**  **SYNA19707**

**(ZC) Tox Category** 

**(respectively)**

Acute Oral LD 50 , Rat **(870.1100)** LD50 >5000 mg/kg LD 50

>5000mg/kg LD50

= 1750mg/kg IV , IV, III
Acute Dermal LD50, Rat **(870.1200)** LD50 >5000 mg/kg LD50

>5000mg/kg LD50

>5000 mg/kg IV, IV, IV

Acute Inhalation LC50, Rat **(870.1300)** LC50 >5.21 mg/L LC50 >5.08 mg/l LC50 >2.59 mg/l IV,IV, IV

Eye Irritation, Rabbit **(870.2400)** Not irritant Slightly irritant Moderately irritating IV, IV, III
Skin Irritation, Rabbit **(870.2500)** Not irritant Not irritant Moderately irritating IV, IV, III
Skin Sensitization (LLNA) **(870.2600)** Negative Sensitizer Sensitizer Not Applicable

2. Genotoxic i ty. Bicy clopy rone has been examined in a range of in vitro and in vivo genotoxicity

assay s, including end points of gene mutation, chromosomal damage and DNA repair. NOA449280 is not mutagenic to bacterial or mammalian cells in vitro and is not clastogenic in human ly mpho cy tes in vitro . It is not clastogenic and does not induce DNA repair in vivo. NOA449280 shows no genotoxic potential either in vitro or in vivo
. 3. Reproductive and developmental toxicity. Reproductive The potential reproductive toxicity of NOA449280 has been studie d in a multigeneration study

in the rat. Dose levels of 0, 25, 500 or 5000ppm, selected on the basis on a preliminary range finding study , were administered in the diet to groups of 25 male and 25 female F0 generation8 rats. Treated diet wa s administered continuously throughout pre

- mating and mating in both sexes and to females throughout gestation and lactation until pups were weaned at day 21. Selected pups were then maintained on diet, forming the F1 generation, were mated at weeks old an d females were maintained until the F2 litters were weaned. NOA449280 had no toxicologically

significant effect on reproductive parameters in either generation. In adults, lower bod ywei ght and bod yweight gain were noted in F0 and F1 animals at 5000ppm and in F1 animals at 500ppm. Sy stemic toxicity was evident in adults at 500 ppm and above including corneal opacity , histopathological and weight changes in the thy roid reflecting minor perturbations in thyroid homeostasis and increased kidney weight accompani ed b y histopathological changes in the kidney, pelvic dilatation , in F1 animals only . At 25 ppm ocular opacit y was noted in F0 males and in F1 males and females. The NOAEL for s ys temic toxicity in adults was considered to be < 25 ppm based on ocular effect s. The relevance of such effects on human risk assessment i s recognised as being low. In pups, body weights gain was reduced in F1 and F2 pups at 5000ppm and in F1 pups at 500ppm. Treatment related ocular effects and kidney weight increase were also evident at these dose levels. The NOAEL for s ys temic toxicity and sexual development was considered to be 25ppm. Developmental A range of developmental toxicity studies have been conducted with NOA449280 comprised of a dose range

- finding study and guideline compliant study

in the Wistar rat, and dose range

- finding and guideline compliant studies in two strains of rabbit: New Zealand White and Himalay an. Groups of 24 bred female Wistar rats were administered NOA449280 b y oral gavage at dose levels of 0, 100, 5 00 or 1000 mg/kg/day on gestation day s 6

- 20, and cesarean section performed on gestation day 21. Effects on maternal bod y weight and weight gain were observed at all doses tested, and food consumption was depressed at the two highest doses tested (500 and 1000 mg/kg/day). There was no evidence of a teratogenic response. Pelvic girdle mal

- positioning (alternativel y diagnosed as the presence of 27 pre

- sacral vertebrae in other laboratories) along with extra rib(s) was observed in all dose group. Slight ch anges in the pattern of ossification were also observed in the foetuses. Effects seen in foetal rats were categorized as variations or slight delay s in ossification that would not be expected to have an y long

- term effects on survival and development. In th e New Zealand White rabbit, dose levels of 0, 10, 50 or 200 mg/kg/day

were selected based on preliminary studies. Groups of 25 bred females were administered NOA449280 b y gavage on gestation day s 7
- 28, and cesarean section performed on gestation day 29. Significant maternal toxicity was noted at 200 mg/kg/day , with decreases in body weight gain9 and food consumption leading to the loss of approximately 28% of the animals at this dose level due to euthanasia, abortion and/or early deaths. There were no tre atment
- related malformations noted at external or visceral examination. Despite having exceeded the MTD, minimal evidence of an increase in a single grouping of skeletal changes, that was considered a malformation in this strain, was noted. These changes, classified as costal cartilage anomalies, though seen at a low incidence, were outside the historical control range. At 50 mg/kg/day , a low incidence of costal cartilage anomalies was within the historical control, though an association with treatment coul d not be excluded. The only statistically

significant treatment

- related changes observed in the New Zealand White rabbit foetuses were increased incidences of an extra vertebra (27 pre

- sacral vertebrae) and an extra (13 th ) pair of ribs in all dose groups. Maternal t yrosine was elevated at all dose levels and skeletal effects of this nature have been shown to be associated with plasma ty rosine elevations, consistent with HPPD inhibition, the known mode of action of NOA449280. These effects are considered to be of no toxicological significance. Two separate studies were conducted with the Himalay an rabbit over a range of dose levels from 1

- 250 mg/kg/day

. The data generated in this strain presented a different picture than that seen in the New Zealand Whit e. Maternal toxicity

demonstrated in this strain was substantially less evident; a low incidence of maternal mortalit y and lower bod y weight gain was observed at 250 mg/kg/day in one of the two studies. Foetal examination produced profiles of two separat e responses to treatment. At 10 mg/kg/day and above, minor skeletal changes consisting of an increase in the foetal incidence (but not the litter incidence) of supernumerary

ribs was observed. At 50 mg/kg/day and above, increases in the litter incidence of caudal displacement of the pelvic girdle (27 pre

sacral vertebrae) and supernumerary ribs were seen. These variations, which are commonly

observed in rabbits, have been shown to be associated with elevated plasma ty rosine and were likely

a reflection of the increase in ty

rosine seen in the maternal plasma The flat dose

- response in these changes parallels the plasma ty rosine levels measured in these rabbits, which rapidl y reached an apparent plateau. Similar skeletal changes were also observed in the New Zealand White rabbit and were correlated with elevated tyrosine. The biological significance of these changes is questionable, and they are generall y regarded as of little or no toxicological significance. Superimposed on this background of t yrosine

- relate d minor skeletal changes was an increase in the overall malformation rate at the high dose level (250 mg/kg/day) in both Himalay an rabbit studies. The malformations affected different organs/structures and were observed at visceral and skeletal examinatio n. At 50 mg/kg/day , there was a slight (non

- significant) increase in the incidence of skeletal malformations.10 These changes were considered to be effects of NOA449280. Overall, the NOAEL for maternal animals was considered to be 50 mg/kg/day

in both str ains of rabbit. At a dose level of 10 mg/kg/day , the only treatment
- related foetal effects noted were minor changes which are considered non

- adverse, or transient in nature; this dose represents a no

observed

- adverse effect level (NOAEL) in both strains of rabbit. A dose of 1 mg/kg/day

has been clearl y identified as a no

- observed

- effect level (NOEL). 4. Subchronic toxicity. The short

- term toxicity of bicy clop yr one has been evaluate d by

the oral route of administration in rats, dogs and mice. In addition, dermal toxicity

was evaluated in rats in a 28

- day study

. Rat NOA449280 was administered in the diet to rats for 90

- day s in two studies, one a preliminary stud y in the AlpkAPfSD rat (Rattray 2003) at dose levels 500, 2000 or 5000ppm and one OECD guideline study in the Han Wistar rat (Shearer 2009) at dose levels 2.5, 10, 2500 or 5000ppm. In neither study

was there a clear treatment related effect on clinical observations, functional observati onal battery (FOB), haematology

or blood clinical chemistry

parameters. In common with other inhibitors of 4

- hy drox yphen yl py

ruvate dioxygenase (HPPD) , the rat is the most sensitive species and toxicity noted in both studies in this case is attributable t o significantly elevated plasma t yrosine concentrations. Dose levels of 2500ppm bicy clopy rone and above resulted in reduced body weight and weight gain in both sexes. The characteristic sign of t yrosine toxicity , corneal opacity

/keratitis, was noted in both sexes at dose levels 500ppm and above. Increased kidney weights were noted in males at dose levels of 500ppm and above but despite a tenfold increase in dose level there was no clear dose relationship and no accompanying histopathological change in the k idney . Similarly an increase in liver weight was noted at dose levels of 500ppm and above in males and 2000ppm and above in females. As with the kidney there was no clear dose response and the change was not accompanied by any significant changes in clinic al chemistry or histopathology

of the liver. The NOAEL in the 90 day

rat studies was 10ppm (equivalent to 0.72 /0.88g/kg bwt/day for males and females, respectively). In a 28

- day

dermal toxicity

study , histopathological effects in the cornea, keratitis and minimal degeneration of the corneal epithelium, were noted in a small number of animals of sexes at 1000 and 250 mg/kg/day . Minor increases in liver weights (< 120% of control) in dosed males were within the historical control range and in the absence o f any associated differences in histopathology or clinical chemistry

were concluded to be of no toxicological significance. Similarly minor increased in kidney weights11 in males were without histopathological correlates and were considered to be of no toxic ological significance. The 28

- day dermal NOAEL was concluded to be 50 mg/kg/day

. Mouse NOA449280 was administered in the diet to mice for 90 day s at dose levels 100, 3500 or 7000ppm to establish suitable dose levels for an 80 week carcinogenicity

study . Administration of 7000ppm (equivalent to > 1000mg/kg bwt/day), the limit dose for this study ty pe, to CD

- 1 mice did not adversel y affect bod yweight or haematology parameters. Dose levels of 7000 and 3500ppm resulted in increased liver weight accompanied b y minimal hepatocy

te h yp ertrophy . At 100ppm minimal increase in liver weight in females on ly

was not accompanied by any change in liver histopathology

and was therefore considered not to be of toxicological significance. A dose level of 100ppm (equivalent to 15.4/20.8 mg/kg bwt/day in males and females respectively) was concluded to be the NOAE L for this stud y. Dog In a 28 day

study at dose levels 10, 100 or 250 mg/kg the male dog dosed with 250 mg/kg bwt/day

NOA449280 was killed for humane reasons after 7 day s of dosing; the top dose group was therefore terminated. Treatment related clinical observations included hy poactivity , unsteady

gait, ny stagmus, opisthotonus, rapid heart rate and vomiting. No adverse pathology was noted in central or peripheral nervous sy stem. There were no adverse effects of treatment following 28 day s dosing at the lo wer dose levels of 100 and 10 mg/kg/day . Plasma t yrosine levels and increased levels of ty

rosine metabolites in the urine were noted at all dose levels and considered to reflect exposure toNOA449280. A dose level of 125 mg/kg/day

was selected as the top d ose level for the 90 day study Following 90 day s dosing at a maximum of 125 mg/kg no adverse effects were noted on bod ywei ght, clinical observations, haematology or histopathology

of organs examined. A decrease in cholesterol was noted in both sexes at 125 mg/kg. An increase in liver weight was noted in females only at 125 mg/kg but in the absence of an y histopathological changes or any similar change noted in the subsequent 1 y ear study this finding was considered adaptive and of no toxicological significa nce. A dose of 125 mg/kg bwt/day

NOA449280 was concluded to be the NOAEL for the 90 day study in dogs. In the 1 y ear study at dose levels of 2.5, 25 or 125 mg/kg one male from the top dose group was found dead after 336 day s; there had been no prior clinic al signs. Signs of toxicity in all animals included corneal opacit y and keratitis in some males and females at 125 and 25 mg/kg and histopathological changes in the nervous s ys tem, chromatoly sis and swelling of selected neurones in the dorsal root12 ganglion and minimal fibre degeneration in the sciatic nerve in some dogs from all dosed groups. A dose level of 2.5 mg/kg/wt NOA449280 was reported to be the LOEL for the 1 ye ar dog stud y . Sy ngenta concludes the No Observed Adverse Effect level (NOAEL) for the 5 2

- week toxicity study in dogs is 2.5 mg/kg based on an increase in corneal opacit y in dogs treated with 25 mg/kg and above. 5. Chronic toxicity. The long

- term toxicity and carcinogenic potential of NOA449280 has been evaluated in a 104 week study in the rat which included a 52 week long

- term toxicity phase and in an 80 week carcinogenicity

study in the mouse. Rat NOA449280 was administered in the diet to Han Wistar rats for 104 week in an OECD 453 guideline study (Robertson and Perry

2012) at dose lev els of 0, 5, 500, 2500 and 500ppm. In common with other inhibitors of 4

- hy droxy

phen yl

- py

ruvate dioxygenase (HPPD) corneal opacity accompanied b y keratitis and regenerative h yperplasia of the cornea was evident from week 4 of dosing until the end of the tre atment period in animals given diets containing 500ppm NOA449280 and above. The findings were noted to be more severe in male rats and towards the end of the 104 week period a low incidence of squamous cell carcinomas and papillomas were noted in male rats at 50ppm and above. Similar tumours have been noted with other HPPD inhibitors in 104 week studies in the rat and are considered to be attributable to the continued damage to, and consequent regenerative hy perplasia of, the corneal epithelium in this most sensitive species. A clear No Observed Adverse Effect Level (NOAEL) for toxicity

to the cornea was identified as 5ppm. Other toxicities identified in the NOA449280 chronic/carcinogenicity study in the rat and identified as resulting from chronic s ys temic exposure to significantly elevated t yrosine are an increased incidence of th yroid hypertroph y and hy perplasia, indicative of a perturbation in thy roid function and also discussed further in and an increased incidence of chronic glomerulonephropath y, accompanied b y elevated covariant kidney weights and changes in urinary proteins, in males rats. The NOAEL for these findings was concluded to be 5ppm NOA449280. Other treatment related findings including an increased incidence of acinar atroph y of the pancrea s in male rats and a decrease covariant heart weight, accompanied in male rats b y a decreased incidence of cardiom yopathy, had clear NOAEL at 500ppm. Mouse N OA449280 was administered in the diet to CD

- 1 mice for 80 weeks in an OECD 451 guideline study (Robertson and Perry 2012). In contract to the13 toxicities noted in the rat but consistent with findings noted for other HPPD inhibitors (Lewis and Botham 2012) long

- term dosing of up to the limit dose of NOA449280 resulted in few adverse effects in the mou se. At the top dose of 7000ppm a slight reduction in bodyweight and bodywei ght gain was noted in both sexes and an increased liver weight was accompanied in males only by an increased incidence of mild centrilobular hepatocy te h yp ertroph y. There was a nume ricall y higher incidence of bronchio

- alveolar adenomas in male mice receiving 7000 ppm NOA449280. However, no similar finding was noted in females and there were no other histopathological changes in the lung. Although higher than the study control, the in cidence at 7000ppm was within the control range of studies running concurrently in the conducting laboratory . This numericall y higher incidence of bronchio

- alveolar adenomas in male mice at 7000ppm was concluded not to be related to treatment with NOA44928 0. A clear NOAEL for the 80 week study in the mouse was 1700ppm equivalent to 233 and 242 mg/kg bwt/day in male and female mice respectively

. Dietary dosing of NOA449280 for 104 weeks to rats has been shown to result in squamous cell tumours of the corne a which are associated with constant damage and repair of the corneal epithelium and can be attributed to the significantly elevated t yrosine levels resulting from HPPD inhibition in this most sensitive species. Although it is known that inhibition of HpPD in humans can result in elevated ty rosine a detailed anal ys is of the mode of action and its relevance to humans against accepted scientific criteria has shown that humans are unlikel y to exhibit the toxicities seen in the rat (Lewis and Botham 2012). In a ddition, the US EPA have recognised that data available for HPPD inhibitors support the view that the high levels of plasma ty rosine seen in male rats and the consequent corneal damage is unlikel y to be seen in humans (Hazard Science Policy

Council Memo D 341612 dated 07/02/2007). Therefore, the tumours noted in male rats are considered to be rat specific and not relevant for human risk assessment. No treatment
- related tumours were identified in the mouse following dietary dosing a limit dose (approximately 1000mg/kg bwt/day) for 80 weeks. It is concluded that NOA449280 does not present a carcinogenic hazard to humans.
6. Animal metabolism. The metabolism and distribution of bicy clop yr one has been investigated in livestock, using laying hens and lactating goats as representative species for poultry and ruminates, respectivel y. In each study bicy clop yrone radiolabelled with 14C in either p yridin yl or bicy clooctenone ring was u sed. Poultry The absorption, distribution, metabolism and excretion of [py ridinyl

14 C]14 NOA449280 and [bicy clooctenone

14 C] NOA449280 were investigated following repeated oral administration to the laying hen **.** Excretion balance and tissue distribution i nvestigations were performed following repeated oral administrations for 10 consecutive day s at a nominal dose level of 20 mg NOA449280/kg of dry diet. The total radioactive recovery was 81% and 79% for the py ridinyl and bicy clooctenone labels respectivel y. The majority of the administered radioactivity was recovered in the excreta (py ridinyl label: 76%, bicy clooctenone label: 76%). The highest residues were found in liver (1.752 mg/kg and 1.776 mg/kg for p yridin yl and bicy clooctenone labels respectively) and accounted for only ca 0.3% of the administered dose. Residue levels in other commodities such as egg y olk, egg white, muscle, peritoneal fat and skin and subcutaneous fat were low and in total accounted for < 0.25% of the administered dose for both radiolabels. Radioactive residues in eggs (mean for a 24 hour period) reached a plateau of 0.10 mg/kg in both labels at approximately

6 to 8 day s. Each of the samples along with excreta was anal yzed for characterization and identification of metabolites and to elucidate the biotransformation of NOA449280 in laying hens. Results from analy sis of samples from both radiolabels provided the following observations:

 Radioactive residues in edible tissues consisted predomi nantly of NOA449280
 There was no appreciable difference in excretion profiles between the radiolabels
 Eggs contributed a minor route of excretion of the radioactivity Lactating Ruminants The absorption, distribution, metabolism and excretion of [py ridinyl

14 C] NOA449280 and [bicy clooctenone

14 C] NOA449280 were investigated following repeated oral administration to the lactating goat. Excretion balance and tissue distribution investigations were performed following repeated oral administrations for 7 consecutive days at a nominal dose level of 30 mg NOA449280/kg of dry diet. The total radioactive recovery was 87% and 82% for the py ridinyl and bicy clooctenone labels respectivel y. The majority of the administered radioactivity was recovered in the urine (py ridinyl label: 60%, bicyclooctenone label: 62%). The highest residues were found in liver (2.726 mg/kg and 2.965 mg/kg for p yridin yl and bicy clooctenone labels respectively) and accounted for only ca 0.7% of the administered dose. Residue levels in other commodities such as kidney , muscle and fat were low and in total accounted for <0.1% of the administered dose for both radiolabels.15 Radioactive residues in milk (mean for a 24 hour period) reached a plateau of about 0.008 mg/kg for both labels at approximately 2 to 3 day s. Each of these samples along with the urine, faeces and bile were anal yz ed for characterization and identification of metabolites and to elucidate the biotransformation of NOA449280 in lactating goats. Results from anal ys is of samples from both radiolabels provided the following observations:
o The principal components present in tissues and milk were unchanged parent and the desmeth yl metabolite CSAA915194. Other minor metabolites were found in liver o O

- demeth yl ation produced the metabolite CSAA915194 o Hy droxylation of the bicy clooctenane ring occurred in 2 or more positions. o Trace levels of a p yridine specific metabolite were observed indicating that cleavage of the rings was a very minor pathway o Very little conjugation was observ ed o There was no appreciable difference in excretion profiles between the radiolabels and distribution of residues was essentially the same for both labels o Milk contributed a minor route of excretion of the radioactivity Metabolism studies conducted in laying hens and lactating goats have provided a detailed understanding of the biotransformation of NOA449280 in livestock. The metabolic pathways in these species are similar. Tissue residues in both animals consisted primarily of parent NOA449280 and CSAA91 5194 (desmeth yl parent) and several very minor metabolites found in the liver for the goat and several samples for the laying hen. Anal ys is of the excreta and urine provided a more detailed understanding of the biotransformation of NOA449280 in these anim als and allowed for a comparison of the metabolic pathway s with that found in the rat. Both animals, goat and hen , show similar biotransformation pathway s for NOA449280. The primary metabolic processes observed include O

- demeth yl ation , oxidation on one or more sites of the bicy clooctenone ring, a minor amount of bridge cleavage between the rings, and conjugation to some extent. Eggs and milk were minor routes of excretion for NOA449280.
7. Metabolite toxicology

. Metabolites that are common to crop and mammalian metabolic pathway s have been assessed as part of the in vivo toxicological assessment of Bicy clop yr one. In addition, based on structural anal ys is, crop degradates are considered to have lower toxicity16 potential than parent Bicy clopy rone and to be of no toxicological significance. 8. Endocrine disruption

. T he bicy clop yrone safety database does not contain an y indication of a potential for direct effects of the compound on the mammalian endocrine sy stem. 9. Immunotoxicity
. The purpose of this study is to provide information on suppression of the immune sy stem which might occur as a result of repeated exposure to a test chemical. Based on the results of this study , treatment of female Crl:CD

- 1(ICR) mice with N OA449280 in the diet for a minimum of 28 consecutive day s did not result in suppression of the humoral component of the immune sy stem. The no

- observed

- effect level (NOEL) for immune suppression was 5000 ppm (equivalent to 1192.3 mg/kg/day). The only

effect attributed to NOA449280 was higher liver weights noted for the 50, 500, and 5000 ppm groups; this effect was not considered to be adverse. There were no indications in this study that NOA449280 was immunotoxic. Similarly , data from subchronic, chronic, an d reproductive toxicity studies of NOA449280 in the rat, mouse and dog, as appropriate, did not provide an y evidence of an effect of NOA449280 on the immune sy stem. Based on data from all relevant studies, Sy

ngenta concludes that there is no evidence of immunotoxicity associated with NOA449280, and therefore, no need to conduct additional immunotoxicity

assessments, specificall y a natural killer cell (NKC) activity assay . C. Aggregate Exposure

1. Dietary exposure. Tier II acute and chronic dietary exposure evaluation was completed for bicy clopy rone (NOA449280) using the Dietary Exposure Evaluation Model (DEEM

- FCID TM ), version 2.16 from Exponent. These exposure assessments included the proposed use on corn (includin g field corn, sweet corn and popcorn). In addition to the corn use, a sugarcane import tolerance was proposed for bicy clopy rone (separate Tolerance Petition and Notice of Filing submitted with this data package) . All residues were below the LOQ (0.01 ppm ) at the 1X label rate and no residues in sugarcane stalks were found even at exaggerated label rates of 3X and 5X. As such, dietary exposure contribution from imported sugar considered negligible and imported sugar was not included in the risk assessment s. The assessments utilized residue data from field trials where bicy clopy

rone was applied at the maximum intended use rate and samples were harvested at the minimum pre

- harvest interval (PHI) to obtain maximum residues. Percent of crop treated values we re estimated based upon economic, pest and competitive pressures. Secondary residues in animal commodities were estimated based on “maximum reasonably balanced diets” and transfer information from feeding studies. Drinking water estimates were incorporat ed directl y into the dietary exposure17 assessment using the higher of the estimated drinking water concentrations (EDWCs) for surface and ground water. All consumption data for these assessments was taken from the USDA’s Continuing Survey of Food Intake b y individuals (CSFII) with the 1994

- 96 consumption database and the Supplemental CSFII children’s survey (1998) consumption database. i. Food. Acute Exposure

. The acute dietary (food only) risk assessment for females 13 to 49 ye ars old was performed using an acute reference dose (aRfD) of 0.1 mg/kg

- bw/day , based upon a rabbit developmental toxicity study with a no observed adverse effect level (NOAEL) of 10 mg/kg/day and an uncertaint y factor (UF) of 100X for intra

- and inter

- species variations; no addition al FQPA safety factor was applied. Acute (food only) exposure to the females 13 to 49 y ears old resulted in a MOE of 178,571 (0.1% of the acute RfD of 0.1 mg/kg

- bw/day). The acute dietary (food only) risk assessment for all general population subgroups w as performed using an acute reference dose (aRfD) of 0.5 mg/kg

- bw/day , based upon a New Zealand white rabbit maternal toxicity study with a no observed adverse effect level (NOAEL) of 50 mg/kg/day and an uncertaint y factor (UF) of 100X for intra

- and inter

- species variations; no additional FQPA safety

factor was applied. The most sensitive sub

population within the infants and children population subgroups was all infants (<1 ye ar old) with a MOE of 295,710 (<0.1% of the acute RfD of 0.5 mg/kg

- bw/day). Si nce the benchmark MOE for this assessment was 100 and since the EPA has no concern for exposures resulting in a MOE above the Benchmark MOE or below 100% of the reference dose, Sy ngenta believes that there is a reasonable certainty that no harm will result from dietary

(food only) exposure to residues arising from the proposed uses for bicy clopy rone. Chronic Exposure. The bicy clop yr one chronic dietary (food onl y) risk assessment was performed for all population subgroups with a chronic reference dose of 0 .0028 mg/kg

- bw/day based on a chronic rat chronic study a no observed adverse effect level (NOAEL) of 0.28 mg/kg

- bw/day and an uncertaint y factor of 100X for intra

- and inter

- species variations; no additional FQPA safety factor was applied. For the purpos e of the aggregate risk assessment, exposure values were expressed in terms of margin of exposure (MOE), which was calculated by dividing the NOAEL by the exposure for each population subgroup. In addition, exposure was also expressed as a percent of the reference dose (%RfD). Chronic (food only) exposure to the U.S. population resulted in a MOE of 31,871 (0.3% of the chronic RfD of 0.0028 mg/kg

- bw/day). The most sensitive sub

population was children (3

- 5 y ears old) with a MOE of 13,284 (0.8% of the chro nic RfD). Since the benchmark MOE for this assessment was 100 and since the EPA has no concern for exposures resulting in a MOE above the Benchmark MOE or below 100% of the reference dose, S yn genta believes that there is a reasonable certaint y that no har m will result from18 dietary (food onl y) exposure to residues arising from the proposed uses for bicy clop yr one. Cancer

. Bicy clop yr one is considered “not likely to be a human carcinogen”. Therefore, no cancer dietary risk assessment was performed for bicy clop yrone. ii. Drinking water
. Tier II acute and chronic dietary exposure evaluation was completed for bicy clopy rone (NOA449280) using the Dietary Exposure Evaluation Model (DEEM

- FCID TM ), version 2.16 from Exponent. These exposure assessments include d the proposed use on corn (including field corn, sweet corn and popcorn). In addition to the corn use, a sugarcane import tolerance was proposed for bicy clopy rone. All residues were below the LOQ (0.01 ppm) at the 1X label rate and no residues in sugarc ane stalks were found even at exaggerated label rates of 3X and 5X. As such, dietary exposure contribution from imported sugar considered negligible and imported sugar was not included in the risk assessments. The assessments utilized residue data from f ield trials where bicy clop yr one was applied at the maximum intended use rate and samples were harvested at the minimum pre

- harvest interval (PHI) to obtain maximum residues. Percent of crop treated values were estimated based upon economic, pest and compe titive pressures. Secondary residues in animal commodities were estimated based on “maximum reasonabl y balanced diets” and transfer information from feeding studies. Drinking water estimates were incorporated directl y into the dietary exposure assessment using the higher of the estimated drinking water concentrations (EDWCs) for surface and ground water. All consumption data for these assessments was taken from the USDA’s Continuing Survey of Food Intake b y individuals (CSFII) with the 1994

- 96 consumptio n database and the Supplemental CSFII children’s survey (1998) consumption database. Acute Exposure from Drinking W ater. The acute surface water EDWC of 2.365 ppb was input directly into the DEEM

- FCIDTM software as “water, direct and indirect, all sources” to model the acute drinking water exposures. Exposure contributions at the 99.9 th %

- ile of exposures were determined b y taking the difference between the aggregate (food + drinking water) exposures and the food (alone) exposures for each populatio n subgroup. Acute drinking water exposure U.S. population resulted in a MOE of 127,551 (0.1% of the acute RfD of 0.5 mg/kg

bw/day). The most exposed sub

- population was females (13

- 49 y ears old) with a MOE of 36,496 (0.3% of the aRfD of 0.1 mg/kg/day). S ince the benchmark MOE for this assessment was 100 and since the EPA has no concern for exposures resulting in a MOE above the Benchmark MOE or below 100% of the reference dose, S yn genta believes that there is a reasonable certainty

that no harm will resul t from drinking water exposure to residues arising from the proposed uses for bicyclopy rone.19
Chronic Exposure from Drinking W ater
. The chronic surface water EDWC of 0.689 ppb was input directly into the DEEM

- FCIDTM software as “water, direct and indirect, all sources” to model the chronic drinking water exposures. Chronic drinking water exposure to the U.S. population resulted in a MO E of 19,281 (0.5% of the chronic RfD of 0.0028 mg/kg

bw/day). Chronic drinking water exposure to the most exposed sub

population (infants, <1 year old) resulted in a MOE of 5,881 (1.7% of the chronic RfD of 0.0028 mg/kg

- bw/day). Since the benchmark MOE f or this assessment was 100 and since the EPA has no concern for exposures resulting in a MOE above the Benchmark MOE or below 100% of the reference dose, S yn genta believes that there is a reasonable certaint y that no harm will result from drinking exposure to residues arising from the proposed uses for bicy clopy rone. 2. Non

- dietary exposure

. There are currently no planned uses for bicy clop yr one that would result in residential handler (mixer/loader/applicator) or post

- application exposure. A nondietary exposure risk assessment is therefore was not performed for bicy clop yr one. D. Cumulative Effects Cumulative Exposure to Substances with a Common Mechanism of Toxicity . Section 408(b)(2)(D)(v) requires that, when considering whether to establish, modif y, or revoke a tolerance, the Agency consider “available information” concerning the cumulative effects of a particular pesticide’s residues and “other substances that have a common mechanism of toxicity”. The EPA does not have, at this time, available data to determine whether bicy clopy rone 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, the EPA has not assumed that bicy clop yro ne has a co mmon mechanism of toxicity with other substances.
E. Safety Determination 1. U.S. population. The acute dietary exposure analy sis (food plus water) showed that exposure from the proposed bicy clopy rone crop uses resulted in a MOE of 104,119 (0.1% of the acute RfD of 0.5 mg/kg

- bw/day) for the general U.S. population. For the acute aggregate assessments, females 13

- 49 y ears old were the most sensitive subgroup with an acute aggregate MOE of 30,303 or 0.3 % of the aRfD (Benchmark MOE = 100; aRfD = 0.120 mg/kg/day). The chronic dietary exposure anal ys is (food plus water) showed that exposure from proposed bicy clop yrone crop uses result in a MOE of 11,667 (0.9% of the chronic RfD of 0.0028 mg/kg

- bw/day) for th e general U.S. population. Based on the completeness and reliabilit y of the toxicity

data supporting these petitions, Sy ngenta believes that there is a reasonable certaint y that no harm will result from aggregate exposure to residues arising from all prop osed bicy clop yrone uses, including anticipated dietary

exposure from food, water, and all other ty pes of non

occupational exposures. 2. Infants and children

. The acute dietary exposure anal ys is (food plus water) showed that exposure from all proposed bi cy clopy rone uses would result in a MOE of 41,995 (0.2% of the acute RfD of 0.5 mg/kg

- bw/day) for infants less than one year old population subgroup. The chronic dietary exposure anal ys is (food plus water) showed that exposure from all proposed bicy clop yro ne uses would result in a MOE of 4,748 (2.1% of the chronic RfD of 0.0028 mg/kg

- bw/day) for infants less than one y ear old (the most sensitive population subgroup. Since all aggregate MOEs exceed the benchmark MOE of 100, Sy ngenta believes that there is a reasonable certainty

that no harm will occur to infants and children from aggregate exposure to residues arising from all proposed bicy clop yrone uses, including anticipated dietary exposure from food, water and all other ty pes of non

- occupational exposure s. F. International Tolerances There are currently

no Maximum Residue L imits (MRL s) set for bicy clop yr one for crops by the Codex Alimentarius Commission and international MRL s for the herbicide bicy clop yro ne have not been established.