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

MEMORANDUM

Date: May 

### 18 , 2015 OFFICE OF CHEMICAL SAFETY AND POLLUTION PREVENTION



### SU BJECT: Zeta-Cypermethrin- Human Health Risk Assessment for a Petition to Amend (Increa se) the Established Tolerances for the Insecticide in Field Corn an d Popcorn Stover, and in Field Corn Forage.
PC Code: 129064 Decision No.: 492384 DP Barcode: D422259

P etiti o n No.: 4F8290 Assessment Type: Single Chemical/ Aggregate TXRNo.: NA Registration No.: 279

- 3 125 , 279-3126 , 279-3426 Regulatory Action: Sec tion 3 Registration Case No.: 2130

MRID Nos.: NA CAS No.: 52315-07-8 40 CFR : § 180.41 8 FR OM: Elizabeth Holman , Ph ysical

**~c~Risk** 

### Assessor

**~** 

### William T. Drew , Chemist 

# 1AJ 

# f

**~** 

### Risk Assessme n t Branch II Health Effects Division (7509P) ;\ ..- THROUGH: Christina Swartz, Branch



# Chie **~/ ~**  Risk Assessment Branch II Health Effects Division (7509P) TO: Julie Chao/Kable Davis, RM Team 3 Invertebrate and Vertebrate Branch 1 ( J VB 1) R egis tra ti o n Divis ion (7505P)

Page 1 of 10 

## 1+.-L--1.0 Exec utive S umm ary Zeta

- cyperm et hrin is a broad-spectrum , pyrethroid insectic id e contai nin g the same eight stereo isomers that are present in cyperrnethrin. However, zeta
- cy perrnethrin is enriched in the four insecticidally activeS isomers, and contains

**%** eac h of th e inactive 

### R isomers

. It is regi stered for both agricu ltu ral and res id e nt ia l u ses . In additi o n , alpha

- cy pe rm ethrin is compri sed of the two most in sec ticida ll y acti ve 

### cis

- 2 isom e rs of cyperrnethrin , a lso with both agricultural a nd re s id e nti a l u ses. Although cy per methrin , a lph a - and zeta
- cyperm e thrin are separate active ingred ients with diff erent end-use products , they are includ ed together in the hazard eva lu ation for the purpose of human health risk assessme nt. The toxicology database for the cype rm ethrin s includ es studies with cyperrnethrin and bo th of its enriched i somers, fo r e valu ati ng potential ha za rd , a nd i s adequ ate fo r risk assessment. In the curren t petition (4 F8 290) , FM C i s proposing l abel ame ndm e nt s specify in g decreased preharvest intervals (PH is) for field com and popcorn , fro m the curre nt 30 days for grain and stover , an d 60 days for forage , to 7 days for all of these commoditie s . FMC is also proposing to amend (by increasing) the current ly estab lished tolerances fo r zeta-cyperrnethri n residues in field corn fora ge o f 0.20 ppm, and in field com a nd popcorn stover of3 .00 ppm . The labe l ame ndm en t s wou ld app ly to three end-use products (E Ps)

. These EPs are Fury 1.5 EC In sec ticid e (EPA Reg i s trati on # 2 79- 3 1 25) , a n emulsifiabl e concent rate (EC) formulation c onta inin g 1

. 5 pounds of active ingredient p er gallo n (lb ailgal) ; Fury 1.5 EW (fo rm erly Mustang) In secticide (E PA R egis tr at ion # 279

- 3 126), an emu l s ifi ab le wate r-ba sed co nc entrate (EW) fom1Ulat i on containing 1. 5 lb a i / gal ; and F911 4 EC Insecticide (E PA Registration #279-3426), an EC formulation containin g 0.8 lb ai / gal. Cypermethrin, zeta -c ype rm ethrin , and a lph a-cypermethrin are Type II pyrethroids that share the same mode of action

. Like othe r pyrethroids , th e cypermethrins cause neurotoxic ity from interaction with sodium channels le ading t o clinical signs of neurotox i c i ty. C lini ca l sign s of neurotoxic ity we r e noted throughout the t oxico lo gy database. The onset of neuro tox ici ty foll owi ng an acute pyrethroid dose is rapid , with a tim e to peak effec t for n e urob e hav ioral effects ranging f ro m 4 to 8 hour s ( W o lans k y and Harrill , 2008; We in e r et a l. , 2009; Sco ll on et a l. , 20 II ). Furthermore , rapid metabo li s m and e limin ation preclude acc umulation and increased potency fo ll owi ng repeated dosing. There fore , for e nd point se lec ti o n and risk assessment , o nl y s in gl e day exposure assessments need to be conducted. No evidence of carcino ge nicity was ob se r ved in carcinogeni c ity st udi es in rats with cypermethrin, or in mic e with alpha-cyp e rm e thrin. H oweve r , lung tumor s w e re see n in females in a ca rcin ogenicity study w ith cy perm ethrin. Cy permethrin is classified as a G ro up C

.. Possib l e hum an carc i nogen . " H owever, the Agency has d ete m1in e d that the quantification of cancer ri s k using a non-l in ear approach ( i. e., RID ) w ill adequate l y account fo r a ll chro ni c tox ic it y , including carcinogenicity, w hi c h could result from ex posure to cyperrnethrin. Whil e th e Agency would typ ica ll y u se a chronic P o pulation Adjusted Dos e (cPAD) to protec t for can cer co ncern s, u se of th e ac ute Po pulation Adjusted D ose (aPAD ) is protectiv e becau s e increas in g to x icity with incr easi ng duration of exposure is not demonstrated for the cyperrne thrin s .

Page 2 of 10There was no systemic toxicity observed via the dermal route, and therefore no appropriate endpoi nt for dermal ri sk assessments. Therefore, only acute dietary , incidenta l oral and inhalation endpoints were selected for risk assessment , all based on neurotoxicity. The dose and e ndpoint for acute dietary risk assessment were selected from the Wolansky et al. (2006) acute oral study, in which decreased motor activity was observed. The dose used for r i sk assessment from the Wolansky study was determined using a benchmark dose (BMD) analysis conducted in accordance with standard Agency assumptions with respect to the benchmark response (BMR). As mentioned previously , there is no increase in toxicity from repeated exposures to the cypermet hrins ; therefore , the acute dietary exposure assessment is protective for chronic dietary exposures since acute exposure levels are hjgher than chronic exposure levels. Accordingly , a dietary exposure assessment for the purpose of assessing chrome dietary risk was not conducted. The Wolansky study was also used to assess incidental oral exposure. For inhalation risk assessments, an inhalation toxicity study in rats was chosen and human equ ivalent concentrations (HECs) were calculated and used for risk assessment. For inhalation risk assessments , the interspecies uncertainty factor was reduced from I OX to 3X because the HEC calculation accounts for pharrnacokinetic (not pharmacodynamic) inter spec ies difference s between animals and humans. Since the la st ri sk hazard characterization was completed (0378897; E. Holman ; 12 October 2012) , HEO ' s approach for calculating HECs has evolved. A new inhalation assessment ba se d on current procedures would result in slig ht changes in the points of departure for inhalation risk assessment for the cypermethrins. However, these slight changes will not change H EO's conclusions with respect to the risk assessment (i.e. the current estimated margins of ex posure (MOEs) are protective). Given different lev els of uncertainty for various risk assessment scenarios , EPA is applying different FQPA safety factors for the protection of fetuses , infants, and children depending on the route of exposure, data gaps and the population expose d. For infants and children less than six years of age, EPA is reducing the FQPA safety factor to 3X, based on the increased quantitative suscep tibility seen in the sc ientific literature related to pyrethroid pharmacokinetics. For adults ( including women of child-bearing age) and children > 6 years of age , EPA is reducing the FQPA safety factor to lX. The level of concern (LOC) for inhalation exposure and risk is 30 for adults and children 6 years of age and over , which includes an interspecies factor of 3X and intraspecies factor of lOX. For children yo unger than 6 years of age, the LOC is 100 based on the FQPA safe t y factor of3X, an interspecies factor of 3X and the intraspeci es factor of I OX. The LOC for incidental oral exposure and risk i s 300 for children under 6 years of age, which include s a FQPA safety factor of 3X, interspecies factor of I OX and intraspeci es factor of 1 OX. Based on the proposed and existing use pattern , short-term (1

- 30 days) and intermed i ate-term (1- 6 months) exposures are expected for occupational hand lers (i.e., mixing , load ing , and apply ing the E P) and during post-application activities (i.e. , re-entering treated areas). ln addition, shortterm exposures are ex pected for commercial and residential handlers who apply the proposed products in reside n tial settings, as well as for adults and children who may be exposed to previously treated areas ( i. e., post-application). Long-term exposures are not expected. Since no dermal endpoint was id e ntified , residential assessments for zeta-cypermethrin are based on Page 3 of 10inhalation and incidental oral (for children) exposures , and occupational assessments are based on inhalation exposures only. Due to the fact that the proposed amended use o n corn had no impact o n th e existin g use rate for the registered products , HED did not conduct a new quantitative occupational exposure assessment for this action. Therefore, occupational risk estimates for the amended use on corn would be the same as those previously assessed for the existing registered products, which were not of concern (M. Collantes ; 0385662; 09/20/ 20 12). The crop field trial data submitted in support of the current action , along with previously reviewed data, are adequate for purposes of risk assessment and tolerance assessment for the proposed amended us e s under review. T hese field trial data are supported by adequate storage stabi li ty data and adequate analytical methods. Maximum residues of zeta-cypermethrin are expected to occur at moderate levels (up to 9.0 ppm in field corn forage, and up to 30 ppm in field corn and popcorn stover) from the shorter PHis on field com and popcorn proposed in the current petition (W. Drew ; D42280 l; 02/20/ 20 15). It is noted that zeta-cypermethrin residues in corn grain were below the limit of quantitation (LOQ) in all field trials ; therefore , the existing zeta-cypermethrin corn grain tolerances do not need to be r evised. For further details on the residues observed in corn , please see Appendix A. All of the tolerances that are being increased are for livestock feed items (corn forage and corn stover) and have the potential to impac t the li vestock dietary burden. However, based on a review of the residue data , the li vestock commodity tolerances that are current ly set are adequate and do not need to be revised (W. Drew; D422801 ; 02/20/ 2015). The existing zeta-cypermethrin use on com was previously included in the dietary exposure assessment (E. Holman; D 403600 ; 9/7 / 2012). Therefore , decreasing the PHI and increasing the zeta-cypermethri n tolerances for popcorn stover, field corn stover, and field corn forage , will have no impact on the dietary risk estimates , as they are already covered in the existing dietary assessment. The results of the dietary exposure assessment are summarized below. Dietary exposure to zeta-cypermethrin may occur from consuming treated crops or their processed commodities. Partially refined (probabilistic) dietary exposure assessments were performed in order to determine the exposure and risk estimates resulting from the use of cypermethrin , alpha-cypermethrin , and zeta-cypermethrin on the crops listed under 40 CFR 180.418. HED has used modeling to estimate dietary exposure to the cypermethrins. The modeling uses conse rvative assumptions regarding residues of zeta-cypermethrin and its breakdown products in drinking water. Since monitoring data was not available for all commodities , the modeling uses a combination of highly conservative assumptions (i.e. tolerance level residues) and monitoring data with percent crop treated information for residues of zetacypermethrin and its breakdown products in food, as well as a n exte n s i ve database of food consumption patterns for the entire U.S. population and var iou s population subgroups. For all registered and proposed uses , the acute dietary exposure estimates are be low HED ' s LOC {< 100 % aPAD at the 99.9th percentile of exposure). Dietary exposure (food and drinking water) for the cypermethrins is 18% of the aPAD for the U .S. population , and 87 % of the aPAD for all infants and children 1-2 years, the most highly exposed population subgroup. Page 4 of 10The aggregate risk assessment for zeta-cypermethrin considers potential ex posure from all cypennethrins (i.e. , cypermethrin and alpha-cypermethrin). The combined res idential adult handler and children's scenar ios previously assessed by HED for the cypermethrins still represent the worst case exposure for each life stage and thus are protective of all other residential uses (M. Co ll antes; 0385662 ; 09/ 20/20 12) ; proposed and exist in g uses result in risk estimates that are not of concern. Cypermetbrin, alpha-cypermethrin and zeta-cypermethrin residential uses are included 

### in the pyrethroid/pyrethrin cum ulative risk assessment (CRA). Given that this petition did not make any changes to the existing use rates for all registered products, these propo sed revisions to the zeta-cype rmethrin field com and popcorn PHi s will have no impact on the cumulative risk assessment. No dietary , resi dential , or aggregate risk estimates of concern have been identified in the single chemical assessment. In the cumulative assessment, residential exposure was the greatest contributor to the total exposure. A lth ough there are residential u ses for cypermethrin. al pha-c ype rmethrin and zeta -cypermethrin , the products involved 

### in this petition are not for residential use. Therefo re , the p roposed revi s ion s will have no impact on the residential component of the cumulative ri sk estimates. 2.0 HED Recommendation s HED has no objection to the proposed PHI revisions for the us e of zeta

- cypermethr in on field corn and popcorn. Pendin g submission of a revised Section F (to propose tole rances in accordance with those reco mmended by HED) , there are no residue chemistry issues that would preclude increasing the currently established tolerances for zeta-cypermethrin residues of0.20 and 3.00 ppm in field corn forage, and field corn and popcorn stover, respectively , to 9.0 and 30 ppm. The recommended tolerances are listed in Table 2.2.3 , below. No risks of concern or data deficiencies were identifi ed. For further detail s on th e earlier risk assessment of zeta

cypermethrin, see D 3 78897 , E. Holman , 10 / 12/ 2012. This assessment su mmarizes the toxicological database in deta il , as well as the re su lt s from the dietary exposure, occupational and re si d e ntial exposure, and aggregate risk assessments assoc iated wit h the existing use pattern. No new quantitative exposure assessments were conducted for the proposed amended uses, since the proposed use pattern and exposure scenarios have been assessed in conjunction with the existing use pattern for the chemical. 2.1 Data Deficiencies None

. 2.2 Tolerance Considerations 2 .2. 1 Enforcement Ana ly tical Method Adequate tolerance e nf o rcement methods are available in PA M Volume If for determining residues of cypern1ethrin , zeta -cypermethrin and alpha-cypermethrin in plant (Method I) and livestock (Method II) commodities. Both methods are gas chromatographic methods with Pag e 5 

### of 10electron-capture detection (GC/ECD), and have undergone successful Agency petition method validations (PMVs)

. Method I has a limit of detection (LOD) of 0.01 ppm , and Method II ha s LODs of0.005 ppm in milk, and 0.01 ppm in livestock tissues. These method s are not stereospecific; thus no distinction is made between residue s of cypermethrin (a ll 8 stereoisomers) , zeta-cypermethrin (enriched in 4 isomers ) and alpha-cypermethrin (e nriched in 2 isomers). The January 1994 FDA PESTDATA database (PAM Volume f) indicates that residues of cypennethrin are completely recovered (> 80%) using multi-residue method Sections 302 ( Luke), 303 (Mills , Onley and Gaither) and 304 (M ill s fatty food).


### 2.2

. 2 In te rn ati on a l H a rmoniz a ti on Currently established US tolerances for cypermethrin, zeta-cypermethrin, and alphacypermethrin are includ e d in the same li sting in the 40 CFR 

### (§ 180.418) , but have separate sections and different crops listed; where there are tolerances for both actives set on the same crop , the leve ls are the same. Mexico adopts US toleranc es, and/or Codex maximum residue limits (MRLs), for its export purposes. Canada has established MRLs for cypermethrin only. There are currently no Canadian MRLs estab li shed for residues of alpha-cype r methrin or zetacypermethrin. There are multip le Codex MRLs for alpha-cypermethrin, but all are in conjunction with MRL s for total cypermethrin i so mers (no MRLs have been estab lished solely for alpha-cypermethrin). However, although the definitions differ formally , they are effectively harmoni ze d since the tolerance-enforcement methods are n ot ste reospecific , and thus do not distinguish between residues of cypermethrin , zeta
- cypermethrin and alpha-cypennethrin. For enforcement purposes , the same mo iety is being regulated. There are no Codex MRLs for cypermethrin , which include s both alpha- and zeta -c ypermethrin , established in com forage or stover. Canada's PMRA does not establish MRL s in livestock feedstuffs , including corn forage or stover. 

### 2

. 2

. 3 R e commende d Tolera n ces The current tolerance express ion for zeta-cypermethrin (40C FR 

### § l80.418[a][3]) is adequate, and include s both coverage and compliance stateme nts for enforcement purposes. HED recommends that 40CFR 

### § 1 80.418 be revised by establishing to lerances for the commodities listed in Table 2.2

. 3.

TAB L E 2.2.3 To l e r a n ce S umm a r y fo r Ze ta-Cy pe rm etbrin. Co mm o d ity P ro p ose d R eco mm end ed C omme nts; Co rrect Comm odity T o l e r a nce ( ppm ) To lera nce (p pm) Definition Com, field , forage 9.0 9.0 Corn , field , stove r 30.0 30 Com , pop , stover 30.0 30

Page 6 of 10

### 2

. 2.4 Rev isions to Petitioned-For To lerance s Instead of the proposed tolerances in field co rn and popcorn stover (30. 0 pp m ), HED recommends estab lis hi ng the to l erances at 30 pp m . The Agency estab lis h es to lerances using whole numbers fo r tolerances of 10 ppm or mo re, per the OEC D 's User Gu ide ENV /

JM/MON0(2011)2 

### for the OEC D tole r ance calc u lation procedure

. 

### 2

. 3 Labe l Recommendation s None. 

### 3

. 0 Chemical Iden t ity**~LE3 0**  zeta-Cy permeth i Jn Nome n cla ture. -· 

# ..**~:** Compound 

### N Il l 

### 0 

# c Cl**~ ~**  

# 0'0 A 0 

# I**I** C l 

## # Common name Zeta-cypermethrin Company experimental name FMC 56701 Molecu lar formu la C 22 H1 9 ChN0 3 Molecular weight 4 16.3 IUPAC name (S)-a-cyano-3-phenoxybenzyl ( IRS , 3RS; IRS , 3SR)-3-(2 , 2

- dichlorovinyl)-2,2- dimethylcyclopropanecarboxylate CAS name (S)-cyano(3-phenoxypheny l )methyl-3-(2,2-d ichloroe th e nyl)

- 2 , 2

- d imethy lcyc lopropanecarboxy late CAS registry number 52315-07-8 End-use products (EPs) Fury 1. 5 EC Insecticide (EPA Registrat ion #279-3125) Mustang Insectic ide (EPA Registrat io n # 279-3 126) F9 1 14 EC Insec ti c ide (EPA R egistration #279-3426) 

### 3.1 P h ys ic a VChemic a l C h a r a cteri s tic s Zeta

- cype rmethri n has a very l ow water sol ubi lity , and re l ative l y high octa n o l / water partitio n coefficient (log Kow > 

### 6)

. These val ues acco u nt for t he low surface an d groundwater concentrations determined by EFE D 's drinking water models

. The che m ical has low vapo r pressure (3 X 

### 1 

# o- 9 

### m m Hg at 20°C), wh i c h decreases its potentia l to volati li ze. 

### 3.2 P es tic i de Us e P a t te rn FMC is propos i ng labe l ame n d m e n ts spec i fy in g dec rease d PH f s for fie l d corn and popcorn, from the current 30 days for grai n and stover, and 60 days fo r forage , to 7 d ays fo r a l l of th ese commodities. FMC is a lso proposing to amend (by increasing) the currently estab li shed tolerances for zeta

- cypermethr i n res idues in fie l d corn forage of 0

. 20 pp m , and i n field co rn an d Page 7 of 

### 10popcorn stover of 3.00 ppm. The label amendments would ap p ly to th ree EP s. T h ese EP s are Fury 1. 5 EC Insecticide (EPA R eg istrat io n #279-3 1 25), an EC fo rmu lati on contai ni ng 1. 5 po und s of acti ve in gred i e nt pe r gall o n (l b ai /gal); F u ry 1 .5 EW In sec ti c i de (EPA R eg ist rati o n #2 79

- 3 12 6 ), an EW f o rmu l at ion contain ing 1 .5 lb a i /gal ; and F 9l1 4 EC In sect ic id e (E PA Reg is tratio n #279

- 3426), an EC fo rm u latio n co nta inin g 0

. 8 lb a i /gal. Because F9 1 14 EC contai n s zeta

- cypermeth rin with a hjgher 

### c is /

trans ratio , it is applied at rates whic h are only half those of the Fury 1.5 EC and Fury 1.5 E W formulations. The proposed revised u se d i rect ions are summarized in Table 3.2 , be low.

TABL E 3.2 S umm ar) o f P ro po se d Use Dir ectio ns f o r Zeta-Cyp e rm ethrin o n F ie ld Co rn a nd P opco rn . Ap p li cation Type ; S in g l e Use Max

. Max. P IIP Us e D irectio n s , Ap p li catio n E quipm e n t • R ate (lb Uses Pe r Se a s on a l Us e (Days) T imin g , a nd L imi tatio n s3 ail A

) Seaso n Rate (lb ail A) Fu ry 1. 5 EC a nd Fun 1. 5 E W En d-u se Prod u ct s Foliar ; ground , aeria l or 0.016

- 0.05 NS 4 0.2 7 Minimum RT I 5 of3 days. May chemig_ation equipment. be applied via chemigation. F9 11 4 EC E n d- u se P r od u ct Foliar; ground , aerial or 0.008-0.025 NS 0.1 7 Minimum RT I of3 days. May chemigation equipment. be applied via chemigation.

. . I. For ground apphcat10n , apply m a mmt mum of 10 gall ons of water per acre (G P A). Do not apply through any u lt ra- low vo lu me (ULV) sp ray system. For aeria l appl ication, apply in a minimum of2 GPA. For c herni gat ion , use o nl y thro ug h s prinkl er sys tems , incl ud ing ce nte r pi vot, latera l move , end tow, s ide (w hee l) ro ll , trave ler, b ig gu n, so l id set , or hand move irrigatio n systems. Do not app ly th roug h any ot her rype of irrigation system. 2. PH I = P r e -H arvest Interval. 3. Begin applications when insect pest populations reach economic threshold levels. 4. NS = Not Spec ified. 5. RTI = Re

- Treatment Interval. 

### Conclusions: The p roposed u se d irecti o n s for application o n fie ld com and popcorn are sufficie nt to a ll ow fo r evalu at io n of t h e s ubmitted res idu e d a ta relative to th e p ropose d u se p atte rn s . 

### R ef e r e nc es W. Drew, 02/ 20/ 2015 , D422801, Zeta

- Cypermethrin. Petiti o n to Amend (In crease) th e Establ i shed T olerances for the Insecticide in Field Corn and Popcorn Stover. and in Field Corn Forage

. Summary of A n alytical Che m istry and R esidue D ata. E. Hol m an, 10/ 1 2/ 20 12 , D37889 7 , Zeta

- Cyperm e thri n- Hum an Hea lth Ri s k Assessme nt for New P o ul try House Use an d Ag ricu l tura l Uses o n Trop ical Fruit , Arti c hoke, Ba rl ey, O at, R ye, Bu c kw h eat , an d Pi s tac hi o. E. Hol m an , 9/7/ 2012 , D403600 , Cypermethrin , Alpha-Cypermethri n , and Zeta-Cypem1ethrin. Acute and Chronic Dietary Exposure and Risk Assessment

- Zeta

- Cyper methri n Uses on Tropical Fruit, Artic hoke , Barley, Oat, Rye , Buckwheat, and Pi s tachio , and A lpha

- Cypermethrin U ses on Various Raw and Processe d Agricultural Commodi ti es.

P age 8 of 10M. Co il antes , 09/ 20 / 2012, D3 85662 , Zeta

- cyperrne thrin. Occupational and Residential Ex posure and Ri sk Assess me nt to Support Prop ose d Us e s on C rop s and in Poultr y House s .

Page 9 of 10Ap p endix A. Summary of Zcta - Cypermetb rin F i e ld T ri a l Data on Co rn Please see 0422801; W. Dr ew ; 02/2 0/2 015 for furth e r det ai ls. TABLE Al S umm ary of Res idu e Data from Field Co rn Fie ld Tria ls w i th Zet a - Cypermetbrin (MRID s #4744 0501 and 4 9412201

. Commodity Total Use Rate 

## Pm Resid ue Leve ls (p pm) (lb ai/A) 1 (Days) nl Min. Max. RA Fr 3 Median Mean S td. D ev. Field com grain 0.20 6-8 15 <0.05 < 0.05 < 0.05 0.05 0.05 0 Field com forage 0.20 6-8 13 0.683 7.09 6.30 2.54 2.59 1.61 Field corn stove r 0.20 6-8 15 0.215 17. 6 1 5.9 3.61 4.76 4.39



## - I. Targe t apphcat1on rate (4 x 0.0) lb ail A). 2. Except for sample minimax, values reflect per trial averages; n = number of field trials. For calculation of median, m ea n and s tandard deviat ion, the LOQ (0.05 ppm) was u sed for a ny re s ult s r eported as < LOQ. 3. HAFT = High est Average Field Trial.

P age 10 of 10