UNITED STAT E S E N VI R O NMENT A L PR OTE CTION A G EN C Y WASHIN G TON D .C., 2 046 0 OFFI C E O F C H EMIC AL S A FE TY AN D POL LUT IO N PREV ENTION

PC Code : 080808 OP Barcod e: 428090 

### Date : Oct

. 28, 2015 

### M EM OR AN D U M SU BJECT : TO :

FR OM :

THR U: Pre l imin ary Risk Assessment for Registra ti on Review of Propaz ine Mar i anne Mannix, Chemical Review Manager A vivah J akob

. Team Leader Kelly She r man, Branch Ch ief Ri s k Management and lmpl e menration Branch 3 Pesticide Re-evaluation Di vis ion (7508 P ) )

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### \.<_ij-j I0 C(- 1 1 Michelle Collett i. Chem ist

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Brian D. Kiernan, Biologist

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## 111 William P.Ec ke l , PhD. , SeniorScicnccAdvisor

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## f,~ E n v ironmenta l Ri sk Branc h 6 E n vi ronmenta l Fate and Effec ts Division (7507P) Mark Co rbin , Branch Chief 

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E n viro nm e ntal Ri sk Branch 6 En v ironme nt a l Fate and Effects Di v is io n ( 507 P)

Th e En v iro nm e ntal Fate and Effects D ivision (EFE D ) ha s co mp l e t

ed the pre liminary e nvi ronment a l fate and eco logical risk assessment ( PRA ) co nducted in s upport of the Reg i strat ion Rev iew o f the triazine herbicide , propazine (PC Code: 080808). T l lis assessment is based o n propazine's cu r rentl y reg i s tered u se s ites; so rg hum (wh ic h is grown in several s ta tes) a nd conta in e r g row n o rn amental s . T hi s document is an abb r ev iated P RA due to it s r e li a nce on th e Sec tion 3 New Use Risk Assess m e nt for pro pa z in e o n so rghum ( DP 310326+) (EFE D
. 2006)

. minimal new data s ubmi ss ion s, and because the use pattern s have rem a ined unch a n ge d s inc e th e 20 06 assessment. R isk conclusions in thi s assessment are s imilar to th ose in th e 2006 assessment and the Reg i s trat ion Rev i ew Prob le m Form u lat ion (DP 407225 ) (EFE D ( I ), 20 1 3). For additional deta il s, p lease refe r to t hose doc um e nt s .Executive Summary and Introduction Propazine (2-chloro-4 , 6-bis(isopropylamino)-s-triazine) is in the Weed Science Society herbicide group 5 (s-triazine) and the Herbicide Resistance Action Committee (HRAC) group C 1, with the mechanism of action of inhibiting photosynthesis in photosystem II (PSII). Propazine is currently registered for preemergence application to control broadleaf and grass weeds in grain sorghum (Sorghum bicolor) plantings and for use on container grown ornamentals in greenhouses (per product label EPA Reg. No. 42750-148). This assessment assumes that the ornamental use is only used inside greenhouses, and causes minimal potential environmental exposure compared to the sorghum use. The risk assessment for sorghum is protective of any risks from green house use. Currently , there is one active end-use product registration for propazine (Propazine 4L ; EPA Reg. No. 42750-148). Propazine may be applied aerially or by ground equipment at rates up to 1.2 pounds of active ingredient per acre (lbs a.i./A). Environmental fate studies suggest that propazine is expected to be persistent and mobile in most soils , and it is resistant to breakdown by hydrolysis and photolysis. If applied in an outdoor environment , propazine has a high potential to leach into ground water or reach surface waters by runoff. The end-use product label specifies that propazine may not be applied within 66 feet of the points where surface water runoff enters perennial or intermittent streams and rivers or within 200 feet around natural or impounded lakes and reservoirs. This preliminary risk assessment identifies potential risk to several taxa (in order of magnitude ofLOC exceedance) : 

### Mammals Potential chronic risk to mammals is identified, with exceedances of the LOC up to 25- fold. 

### Terrestrial Plants As expected with an herbicide, risk to terrestrial plants was identified , with exceedances of up 13-fold. 

### Birds Potential chronic risk to birds is indicated using the LOAEC from the northern bobwhite quail study; a NOAEC is not available , but the magnitude of the LOC exceedance is expected to increase with the submission of new data. 

### Aquaticplants Risk is indicated for listed aquatic vascular plants and for both listed and nonlisted aquatic nonvascular plants, with exceedances of up to nearly 7

- fold. Three chlorotriazine herbicides have current registrations in the United States: propazine (6- chloro-N ,N'-bis(l

- methylethyl)-1,3 , 5-triazine-2 ,4-diarnine) , PC code 080808; atrazine (6-chloro2N

- ethyi-N'

- (1 -methy lethy l )-1 ,3, 5-triazine-2, 4-diamine) , PC code 080803; and simazine (6- chloro-N,N'-diethyl-1 , 3 , 5-triazine-2,4-diamine) , PC code 080807. These three chemicals differ only in number and/or position of methyl groups on moieties branched in id e nti cal positions off the tri azine ring , thus are structura ll y nearly identical (Figu re 1 ). Based upon the available guideline and non-guideline toxicity studies , these chlorotriazines result in s imil ar herbicidal effects to terrestrial and aq u atic plants. These molecule s bind with a protein complex of th e photosy ste m II in chlorop last photosynth etic membranes (Schu lz et al., 1 990). The resu lt i s an inhib ition in the transfer of electrons through the light reactions of photosynthesis that in turn inhibits the formation and re lease of oxygen , production of adenosine triphosphate , and the fixation of carbon dioxide into s ugars. In terrestrial animal s, the g uideline studies for all three ch lorotriaz ines hav e s hown simi lar effects at similar dose s and concentrations (see atrazine PRA, docket EPA-HQ-OPP-20 1 3-0266 and s imazine, docket EPA

- HQ-OPP-20 13-0251 ). The se effects include food avoidance and/or reductions in frank weights or we ight gain , although post-exposure recovery is frequently noted. The s imilaritie s of effec ts in mammalian studies have led OPP's Hea lth Effects Di v i sion to consider atrazine, simaz ine , propazin e , and their chlorotriazine degradates in a cumulative human hea lth risk assessment (althou g h th e eco l og ic a l assessments are not cumulative). Un like atrazine , propazine and s imazine do not h ave the wealth of non-guideline eco logical effects data 

### (e.g., mesocosms, amphibians , academic research) that h ave informed the atrazine registration review ecological risk as s essment. The ecologica l risk asses s ment presented in this document is for the active ingredient propazine only. However , EPA considers it reasonable to assume that if a simi lar body ofliterature was available for propazine or simazine , risk conc lu s ion s similar to atrazine m ay be reached.



### 3

### USE PATTERN Propazine was ini tially registered in 1958; however, all propazine registrations were canceled in 1988. Propazine was subsequently registered for non-agricultural uses in 1998, and in 2007, it was registered for use on sorghum. Propazine is also registered for use in greenhouses on containerized ornamentals (shade trees , herbaceous plants, non-flowering plants , and woody shrubs and vines). A map by the US Department of Agriculture (USDA) of the sorghum production area is shown in Figure 1 below. Figure 1 depicts counties in the US with the highest acreage of sorghum production, and where propazine usage is expected to be high compared to other parts of the country; however, propazine may not be applied to all sorghum plantings. The current labeled maximum single app lication rate on sorghum i s 1.2 lb s a.i./A. Only a single application of propazine is permitted per year for use on sorghum and shou ld not be applied if atrazine ha s or will be applied to the same area in the same growing season. Application s can be made by aerial , ground eq uipm ent , and by t-band application. Propazine , per the currently accepted labe l, is not registered for use on sorghum in the states of California or Florida. 

### In addition, the application of propazine on sorghum, as specified by the label, prohibits use on sand and loamy sand so il s.

Ac re s l«<l>l""'"' 

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. Sorghum 2013 Pl:llltod Acros by County f or Selected St:ltos

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### 1 : Sorghum planted acres in 2013. Source: USDA National Agricultural Statistics Service , 2013.

4C O NCEPTUAL M OD EL A conceptual model for propazine was included 

### in the 2006 Sec tion 3 New Use Assessment to consider a ll potential routes of exposure (OP 3 1 0326 +) (EFED, 2006). This pre l iminary ri s k assessment expands on th e risk conclusions of the 2006 New Use Assessment but makes no changes to the conceptual model or diagram s. 

### R isk H ypo th es i s The fo ll owing risk hypothe s is is presumed for this pre l iminary r isk assessment: Based on the mobility and p ersiste n ce of propazine, the mode of action, and the nature of the use patterns , propazine has the potential to cause reductions in survival , reproduction and growth impairm en t for both aquatic and terrestrial animal andplant species. ENVI R O NMENT AL FATE P ropazine is expected to be moderately persistent and mobil e in most soils , and it is resistant to breakdown by hydro l ys i s , photolysis , or biodegradation. T a bl e 1 below summarizes the ph ys ical and chemical properties of prop az ine. Further de scription of the physicochemical propertie s ofpropazine are available in the 2006 Ecological Risk Assessment ( OP 3 10 326 + ) (EFED , 2006)
Ta bl e l. P hys ical a nd C h e mical P ro pert i es of Prop a zin e Prope rty Value R eference Common name Propazine Chemical name CAS : 6-chloro-N , N' -bis( 1-methyl eth yl)- I, 3, 5- triazine-2 ,4-diam ine IUPAC: 2

- ch lor o-4 ,6-bi s(isopropy lam i no)-s-triazine CAS number 139-40

-2 Chemical Structure 0',

# ~ Cl\

# J)~A;:Cl\ Molecular formula C 9 Ht

6 C1Ns Product Chemistry Molecular weight 229.71 Product Chemistry Ph ysical state Crystalline solid Product Chemistry Meltin g point 2 1 2-2 14 ° C Product Chemi stry Vapor press ure 2.9 x I0 · 8 nun Hg at 20 ° C Product Chem istry Water solubility 8.6 mg/L water at 20 ° C Produ ct Chem istry Henry' s Law Constant 1 .02 x I0· 9 atm.m 3/ mol {Worthing , 1983) (ca l cu lated) Produ ct Chem istry LogKo w 2.91 (Montgomery. 1993) , Product Chemistry pKa 1.85 at 22 ° C (Montgomery , 1993 ) , Product Chemistry 5Stud ies suggest that propazine is stable to both abiotic processes of hydrolysis and aqueous photolysis. Propazine is also fairly stable under aerob ic and anaerobic aquatic metabo li s m with half-lives ranging fro m 146 to 1240 days (extrapolated past the end of the study) and 69.3 to 1 22 days respectively. B atc h eq uilibrium exper iments suggest that propazine is mobile , w ith Freund li c h 

### K<t values ranging from 0.34 to 3.19 in two separate stu di es in vo lving 8 so il textures. The Koc val u es ranged from 65 to 268 in these same studies. The mobility of propazine is a lso noted in the supplemental terrestrial fie ld d i ssipatio n s tud ies, suggesting that propazine persists in the upper 6 inches and may leach to ground wat er. It has also been reported in the li teratu r e that if released to soil, propazine wi ll persist lo nge r in dry or cold conditions or other conditio n s which inhibit biological and c hem ica l acti vity (Worthing, 1983). Therefore, it is very like ly t h at the use of propazine may res ul t in groundwater and/ or s urf ace water contamina tio n in areas where soils are highly permeable , the water table is sh a llow, or where there is i rrigation and/or hi gh rainfall which promote runo ff

. Vo latility an d air p ho to l ysis are not expected to be major routes of dissipation due to the lo w vapor pressure (2

. 9 x 1 

# o-s torr at 20°C)

. 

### Table 2 b e low summarizes the e n vi ronme ntal fate and transport properties of propaz in e .



### Table 2

. Summary of**Environment~)** 

### Fate and Transport Properties**fo~** 

### Propazine P aram ete r Hydrolys is half -life (25 ° C, pH 5, 7, & Aqueous photolysis ha lf-life (25 ° C)
Aerobic aquat ic me tabolism half-lif e (20°C)
Anaerob ic aquatic metabolism halflife (20°C) Persistence in Soil Soil photo lys is half-life (25 ° C) Ae rob ic so il metabol ism half -l ife (25 ° C) Anae robic soil me tabol ism half-life (200C) Mobility Organ i c carbon partitioning coefficient(Koc. L·kg- 1 /Kd) Value SWCC Model R e ference Input (MRID #) Persistence in Water Stable 0 43689802 Stable (24 -hr irradiation xenon arc lamp; 211 0 44184805 days dark control) Go lden Lake Sandy Loam- 1 240 days 1 2380 days2 (D FOP) @20°C 481258 0 2 Goose River Clay Loam - 146 days 1 (DFOP) Go lden Lake Sandy Loam- 122 days 1 (SFO) 177 days2 48125803 Goose Riv er Clay Loam- 69
. 3 days 1 (SFO) @2 0 °C
Stable 44184806 KY Sandy Loam- 423 Days 1 (SFO) 1269 days3 44184 807 8 Weeks ( loamy san d soi l) 00153713

83 / 0

. 34 (loamy san d) ; 123 / 1 .14 (sandy loam ); 00152997 158/2.69 (loam); 65 / 3 .1 9 (clay loam) 125 3 268/0.67 (sand); 128 / 1.28 (sandy loam); 43689804 96/1

. 30 (s il ty clay); 79/ 1 .35 ( l oam)

6Pa r ameter

F ie ld Dissipation

Terrestrial field dissipation half-life Value 2-hydroxy-propazille 145/ 1.45 (sandy loam) ; 329/0.28 (sand) ; 78/ 1.33 (loam ); 342/4.57 (silty clay)

NC (Wilson Co) 1 .2 lb a i/ A- bare ground sandy loam (0-6") and sandy clay loam (6

- 12" ) *Not suitable for half-life calculation TX (Armstrong Co) 1.2 lb ai/A- bare g round loamy sa nd (0-6" and 6- 12") T**~=52** day s ( 186-day study) 1Half-live s recalculated using PestDF 0.8.13 (EFED ( I ) , 2015) 2 90th percentile confidence bound on the mean half-life val ue (EFED (2) , 2015) 3 EFED Input Parameter Guidanc e (E FED (2), 20 15 ) ··No time 0 samp le was reported for Terrestrial Field Dissipation Study (442873 14) D eg radates: SWCC M ode l Input Reference (MRID#)
44287313

44287314

44184809

The 2006 Section 3 New Use ofpropazine for sorghum (DP 3 1 0326 + ) did not include degradates in its analysis. Potential degradates (see below) that propazine has in common with atrazine and simazine are DEA and DACT. DIA is not a degradate of propazine. Because of the greater stability of parent propazine , relative to atrazine and simazine , inclusion of degradates would not change the conclu s ions of the risk assessment. One major degradate , hydroxy-propazine , was not included in the 2006 sorghum new use assessment because h ydroxy degradates were determined to not be of toxicological concern in the assessments for atrazine and simazine; al so, no environmental fate data were available. Because of lon g parent half -li ves in soil and aquatic systems, thi s assessment considers this as an uncertainty but will not model a total toxic residues approach.



### 7G-30027 Atrazine ATZ G-30033 Desethylatrazille DEA

G

- 30028 Propazine PRZ G-28279 O

es iso propy latra zi tt e DLA

G-27692 S

imazin e SIZ G-2827 3 Diat uiuocltloroarrazine DACT



### Figure 2. Structures of s-chlorotriazines parents and transformation products. 

### ECOLOGICAL EFFECTS Aquatic Fish and Invertebrates: 

### Aquatic effects data, as reported in previous documents, are summarized in Table 3 below. Although the LC 50

### s fo r aquatic fish and invertebrates are near or above the so lubili ty limit of propazine, sublethal effects (such as loss of equilibrium) were observed in all the acute studies. An acute exposure study with the rainbow trout (MRID 47452301; Acceptable), not previously described , resulted in the lowest frank endpoint for fish at a concentration s imilar to previously reported non-definitive values. In that 96-h study , rainbow trout (Oncorhynchus mykiss) 

### were exposed to propazine at mean - measured concentrations of limit of quantitation (<0.0266 mg a.i./L , negative and solvent controls) , 0.56 , 1.19 , 2.28 , 4.51 and 8.26 mg a.i ./ L under static conditions. The 96-h LCso was 5.00 mg a.i./L. The observed NOAEC value, based on sublethal effects, was 2.28 mg a.i/L. Sublethal effec ts included fish laying on bottom of test chamber and discoloration at 4.51 mg a.i

. /L

. Based on the re sults of this study , propazine is classified as moderately toxic to freshwater fish on an acute exposure basis. Aquatic Plants: 

### Studies for all four required taxa of nonvascular aquatic plants have been submitted; while the most sensitive endpoint is shown , other taxa are affected at s imilar concentrations. Growth of the aquatic vascular plant , Lemna gibba, 

### is also inhibited by exposure to propazine.

8Table 3. Summary of the Most Sensitive Endpoints from Aquatic Toxicity S tudies for 

### p rop az me. Ta xo nom ic Study S urrogate Species Toxicity Valu e Acute So urce

G ro up T y p e T ox ici ty (S tudy C lassification c l ass ification)
Ra inbow Trout L Cso = 5

. 0 mg Acute (Oncorhynchus ai/L (observed Moderate l y 47452301 NOAEC: 2.3 toxic (Acceptable) mykiss) mg ai/L) NOAEC = 0.56 Freshwater fish 1 Chronic mg a i/L (Early Fathead Minnow LOAEC = 1. 23 48036205 Lif e - (Pim eph ales mg ai/L 

## -- (Acce pt able) promelas) Endpo int : Stage) reduction in !rrOWth ECso > 5.32 mg Acute Water F lea ai/L (observed Moderately 44287305 (Daph nia ma g na) NOAEC: 5.32 toxic (S upplemental ) mg ai!L) Freshwate r N OA EC = invertebrates 0.047 mg ai/L LOAEC = 0.091 44327602 Chronic Water Flea mg a i/L 

## -- (Acceptab le) Endpoint: reduction in growth Sheeps head LC so > 3.87 mg Acute Minnow ai/L (obse rved Moderate l y 48036204 (Cyprinodon NOAEC: 2.0 1 toxic (Accep table) variegatus) mg ai/L) NOAEC = 1.34 Est uar in e / marine mg ai/L fish Sheepshead LOA EC = 2.59 C hronic Minnow mg ai/L 44 1 84802 (36 day) (Cyprinodon Endpoint: 

# - - (Supp lemental) variegatus) embryo survival and hatching success Mysid LCso = 4

. 2 m g Acute (A m ericamysis a ilL (observed Mode r ately 44 1 8480 1 NOAEC: 0 .5 86 tox ic (Acce p table) bahia) mg ai/ L) Estuarine/ marine N OAEC = invertebrates 0.266 mg ai/L Chronic Mysid LOAEC = 0.474 44 184803 (28 day) (A m ericam ysis mg ai!L 

# -- (S upplemental) bahia) Endpoint: reduc ti on in growth N OAEC = Aquatic plants Vascular Duckweed 0.022 mg ai/L 44287309 (Le mna gibba) lCs o =0.1 mg 

### -- (Accep table) a ilL 9Taxonomic Study Surrogate Species Toxicity Va lu e Acute Source Group Type Tox icity (Study Classification classification)
Freshwater diatom NOAEC 

### = Non- (Navicula 0.0065 mg ai!L 44287310 vascular IC so 

### = 0.0248 

## -- (Acceptable) pe/liculosa) mg ai/L

. . 1 Fre s hwater fi sh may be surrogate s for aquatic-ph ase amphibian s. 

### Terrestrial Terrestrial animal effects data are summarized in Table 4 below. Terrestr i al plant toxicity data are summarized in Table 5. Birds: Propazine is classified as practically nontoxic to terrestrial birds from acute dose-based or dietary-based exposure; however, an acute oral study for passerines is not avail able for propazine. Sub lethal effects (decreased weights) were noted in both the bobwhite quail and the mallard duck acute oral and subacute dietary studies , suggesting chemical-induced anorexic response at 430 mg a.i/kg-bw and up. Additionally , adult female weight gain was s i gnificant ly affected in both mallard duck and bobwhite quail reproduction studies, with s i gnificant effects at the lowest dose in the bobwhite study. Therefore, an avian NOAEC is unavailable for the risk assessment. A subacute dietary study (MRID 49635701) with zebra finch (Taeniopygia guttata) was recently submitted and is currently under review. The study was submitted in response to the registration review DCI requiring an avian acute oral toxicity study with a passerine. A dietary study was conducted due to regurgitation observed in the range-finding study. Based on a preliminary review of the study report , the birds were exposed to mean-measured dietary concentrations of 0 (control) , 326,712, 1560, 3190, and 5290 mg ai/ kg-diet with an LCso of2837 mg a.i.lkg -di et. Based on this, propazine wo uld be considered sl ightly toxic to passerines on a subacute dietary basis. From the study report: Abnonnal behaviors were observed from Day I through Day 8 of the study , at the 712 mg a.i./kg feed treatment leve l through the 5920 mg a.i./kg feed treatment leve l, and includ ed asthen ia , piloerection , hyp oactiv ity and lethargy. Mortality reached 80% and 90% of birds exposed to the test substance at 3190 and 5920 mg a. i./kg feed, respectively. Mortality did not occur at any other treatment l evel, nor among the contro ls. All treatment gro up s experienced a significant reduction in body we i ght during the exposure period compared to the control g r oup . Birds at the 326 and 712 mg a.i./kg feed treatment levels recovered near-contro l body weights during the post-exposure period and over the entire course of the study. However, net body we i ght gain among birds at the 1560 and 3190 mg a. i./kg feed treatment l eve ls remained significa ntl y l ower than the contro ls during the post-exposure period and over the course ofthe entire study. In similar fashion, average daily feed consumpt i on was significantly lower at all treatment levels compared to the control , and remained s li ghtly lower (thought statist i ca lly sign ificant) than the contro l in the 3190 mg a. i./kg feed treatment group during the post-exposure period. There remains an avian effects data gap for propazine: an avian reproduction study with the bobwhite quail (OCSPP Guideline 850.2300). The study was required through the registration review data call-in issued on Ap ril 30, 2014, but data have not yet been submitted to EPA. 10Mammals: Propazine is classified as pract ica ll y nontoxic to mammal s o n an ac ute exposure bas is , but effec t s from chronic ex po sure (adul t toxicity and repro duction effects) were observed as l ow as 50 mg ailkg-bw / day. Te rres trial invertebrates: Propazine i s c la ss ifi ed as practically nontoxic to h o n ey bees on an acute contact bas i s. How eve r, propazin e u se may be o f ex p os ure concern fo r pollinators v i s itin g plant s that are contaminated by direct app li cation or spray drift. The compl ete s uite of hon ey bee adult and larvae s tudi es have not been submitted fo r propazine, and these data are needed to fulfill EPA 's recent policy on po lli nator protection 1 • A Tier I study on the toxicity of residues o n foliage (OCS PP 850 .3030) is not ne e ded s in ce r es ult s of th e honey bee acute contact 

### LD so i s > 96.7 )l g a.i./bee, well above th e 1 1 )l g a.i./bee trigger criter i on. T he fo llo wing Tier I , II and 

### lii hone y bee s tudies , yet to be s ubmitted for propaz ine , are r eq uire d 2 :
o Hon eybee adult acute oral t ox ici ty s tudy (fo ll owing OECD 237 , Tier I) o Honeybee larval acute oral toxicity study (fo ll owin g OECD 237 , Tier I) o Honey b ee adul t 1 0-day c hroni c oral (special study; Tier I) o Honeyb ee larval chronic oral toxicity study (T ier I) o Semi-field te s ting for pollinators (special st udy , Tier II) o Field testing for pollinators (OCS PP 850 .3040 , Tier III) o Field trial of residues in po ll e n and nectar (speci a l study , Tie r Ill ) Terrestrial plants: As expected with an herb ici de, propazine adve rse l y affects p lant s . Effects were see n in both t he seed lin g e mergence and vege tative vi go r studies and in both monocots and dicot s . For some s pe c ies in these s tudie s, NOAECs were not d eterm ined ; in th ese cases the IC 05 will be used to estim ate risk to li sted plant spec ies.

1 (Guidance for Assessing Pe s ti cide Risks to Bee s, 06.23.2014 ; signed by Donald Brady, Director, EFED;

hnp: //www2.epa.gov/ site sl productionllile sf 20 14- 06/docume nt pollinator ri s k a s sessment guidance 06 1 9 1-t. odO 2 The need for higher T ier se mi-field and full field pollinator studies for p ropazine w ill be determined after review

of these T ier I stud ies. 11

### Table 4. Summary of the Most Sens itive End points from Terrestrial Animal Toxicity Studies

Ta xo nomi c Study T ype Su r rogate Species Toxicity Val ue Ac ut e Toxic ity Source (Study G roup Class ificat ion cl ass ifi cation)
L Dso > 1640 mg Bobwhite quai l ai/kg-bw P ractically non - 44287301 Acute (Co/inus Observed NOAEC 

### = 244 virginianus) mg ai/kg

-bw based on tox ic (Acceptable) weight
LC so > 4930 mg ai/kg-d i et Bobwhite quail Effects on we i ght/food Practically non- 44287302 (Colinus virginianus) consumption were t oxic ( Accep tabl e) observed at all dietary Sub

- acute concentrations (LOAEC Birds d ietary 578 mg ai!kg-d iet)

LC so = 2837 mg ai/kgZe bra fmch diet (o bserved NOAEC S li ghtly t oxic 4963570 1 (Taeniopygia guttata) not dete rmin ed bas ed on (under review) weight)
NOAEC <262 mg ai/kg

- diet Chron ic Bobwhite quai l LOAEC = 262 mg 4803620 1 ai/kg-diet Endpo in t: 

## -- (Supplementa l ) adult fema l e body weight gain Acute Oral Laboratory rat LDso :::._5 050 mg Practically non - 4347410 1 (Rattus norvegicus) a i /kg-bw toxic (Acce ptable ) NOAEL=5 mg J
. Morales et a t. 0 323271 12/ 13 / 2005 Mammals ai/kg/day LOAEL 

### = Pro paz in e. Rev i sed HED Chron ic Laboratory rat (Rattus 50mg



## -- Risk Assessment for the norvegicus) ai/ kg/day Endpoint: rTolerance Reassessment pare ntal toxicity and Eligibility Decision rep roductive effects Do cument (TRED) I nsects Acute contact Hon ey bee (Apis LDso > 96
. 7 f,lg a i /bee P ractically non - 00036935 m ellife ra) toxic (S up p le m e ntal)



### 12

### Tab le 5. Plant endpoint summary by species (MRID 44184804; Acceptable) See dlin g E merge n ce NOAEC S pecie s E ndp o int (lbs a.i.!A ) Com None 2.4 Oat Biomass 0.019 1 Onion B iomass 0.0087 1 .2 Ryegrass Bioma ss 0.077 Wheat Bi omass 0.01 Cabbage Biomass 0

. 049 1 C ucumber Emergence 0

. 042 1 Lettuce Biomass 0.0047 Radish Biomass 0.077 Soybean B iomass 0.59 Tomato Bioma ss 0.039 1 1 1

Cos used as a NOAEC not determined. 2 Bo ld indicates mo st se n sitive. 

### Environmental Fate and Exposure Vegetative Vigor I C2s NOAEC (lbs Endpo int ( l bs a .i.! A) a. i./A) > 2.4 None 2.5 0.050 Biomass 0.0022 0.035 Biomas s 0.075 0.83 Biomass 0.075 0.14 Biomass 0.02 0.098 Biomass 0.011 0.12 Bioma ss 0.047 1 0.0 1 6 Biomass 0.075 0. 16 Biomass 0.075 0.97 Biomass 0.038 0.18 Biomass 0.038 IC2s (lbs a. i./A) > 2.5 0.11 0.096 0.17 0.046 0 .1 3 0

. 10 0.10 0.22 0.66 0.15

The current risk assessment uses the Surface Water Concentrati on Calculator (SWCC) version 1.1 06 , which uses PRZM (ver sion 5.0 + ) and the VVWM (variable vo lum e water model), a replacement for the older EXAMS mode l , for Ti er 2 surface water assessments. The Tier 2 assessment reports th e highest peak , 21-day and 60-day average estimated envi ronmental concentrations (EEC) for propazine that are expec ted to occur once every ten years. The estimates are generated u sing 30

- years of meteo rological data , e ncompass in g the years f rom 1 961 to 1990

. For furt her inf o rm ation on thes e models see : http: //www . epa.gov/ oppefedl / models/ water / index.htm. 

### Scenario Selection Simi lar to modeling conducted for the 2006 New Use Assessme nt , the agricultural use of propazine for broadleaf weed contro l in sorghum was simulate d in thi s risk assessment with the so rghum c rop scenarios for Kansas and Texas. Note that the non-standard Texas so rghum sce nario was developed for the cumul ative assessment for the organophosphate insecticides (2002) and is u se d in this assessment to provid e spatial context to th e EECs generated using th e standard Kansas sorg hum scenario. The e n v ironmental fa te input parameters used in the SWCC model are li sted in Tab le 1. The spray dri ft fraction was calcu lated u sing AgDri ft version 2.1. 1 using EFE D Gu id ance on Modeling Offs ite Deposition of P esticides via Spray Drift for Ecological and Drinking Water Assessments (EFED (2) , 20 15 ). The propazine e nd-u se product label specifies that propazine may be app li ed prep lanting , after the soi l is plowed; and preemergence , at or immediately after p lan t in g before weeds and so rghum emerge. Appl ication dates for mod e l ing in SWCC are at 1 3

### p l anting , preem ergence . Additio nal inp u t parameters are prov ided in T abl e 6
. T able 6 : Additional S WCC Input Pa ramete rs Maximum Use S i te Rate (lbs Interva l Date Spray D rift A pplication a .i./ A) fraction Effic iency At Plant 0.0078 0.99 (ground) I appl ication I (Re lative to ( ground) Sorghum 1. 2 se as o n ' plan ting dat e in 0.95 (aeria l ) 0

. 03 14 SWCC) (ae r ia l ) 1 Whi le th e label sp e cifi es per se a s on , mu ltipl e p lant ing se as ons per ye ar are doubtful for so rghum

. T a ble 7 . Estimated E nvironmenta l Con c entr ation s (EE C) of propa z ine residue s for s or ghum in th e S tand ard Pond with the S W CC model. T he s imulations used the max imum labeled number of appl ications (I) and maximum appl ication rate (1.2 lb. a. i.I Napp iication). 1- i n- 10 year Propazine Concentration (J.tg/L) Scenario -State Crop Peak 21- Day 60- Day KS

- Sorghum

Aeria l Spray 36.3 35.7 35.1 Ground Spray 32.5 32.0 31.5 TX

- Sorghum ( OP) Aeria l Spray 42.8 41.7 40. 1 Ground Spray 40.8 39.8 38.2



### Monit o ring Data Mo n itoring data for propazine were downloaded fro m the Water Q ua lity Portal datab ase (http : //wate rq ua li tydata.us/) o n Apri l 1 0, 20 1 5. T he Water Q ual i ty Portal in tegrates d ata from the U SGS Nati on al Water I nformation Syste m (NW IS) , EP A's STORET data wareho u se , and US D A ARS STEWARDS p latfo rm. A total of38 ,2 17 records were analyzed for propaz ine . The organizations in Table 8 below contributed to the moni toring data rangi ng in date from 1 9 77 to 20 1 5 ; howev er , only mon itoring data from the 1990 ' s forward we re incl uded in the fo ll owing summ ary. The co ntrib utors inc lu de state and fede ra l age n c ies and In dian tribes. At least n in e states and four trib es are represe n ted.

14

### Tab le 8 : Monitoring Data for Propazi n e
S a mpling O r ga nizat i on Numb e r of r eco rd s in S TORE T Kansa s Dept. of Health and E nvironment 17,622 I owa Dept. Natural Resourc es 13 , 387 M

inne sota Dept. Agricu l ture 3 , 344 Indiana STORET data 978 Iowa Geol ogic al Survey 738 U

pper Sioux Community 529 Arkan sas Dept. Env i ronmenta l Quality 456 National P ark Serv ice Water Resources Di v. 382 US Army Corps of Engin ee rs, Omaha District 357 Kentuc ky Div

. of Water 271 California SWMP 255 Minne so ta Pollution Control Agency 80 EP A Region 7 36 US Fish & W ild li fe , NM Eco l. Serv ices Field Office 34 Flandreau San tee Sioux 31 Lower Sioux Lnd ian Community (MN) 10 Fort McDowell Yavapai 5 New Mexico Env. Dept ./ SWQB 2 TOTA L RECORDS 3 8 , 2 17 P ropazine was detected in 271 samples (0.7%); a further 361 s amples are listed as detects , but appear to be reported as det ect ion l i m it s ( 0.05 ug!L or lower)

. Of the samples with detectabl e propazi n e, 5 exceeded 1 ug/L, 8 samples were between 0.5 to 1.0 ug!L , 22 samples were 0

. 25 to 0.5 ug/L, and 595 were 0.25 ug!L or less. Of the 35 samples measuri ng 0.25 ug!L or higher, 20 were i n Kansas , 9 we re in Iowa , and 2 were taken by the US Army Corps of E ngineers. No moni toring data were retrieve d from the Wate r Quality Portal for Texas , which is expected to be a major u se area for propazin e on sorghum. Water bod ies w i th d etecti ons above 1 ug/L we re a ll i n Ka n sas, and in cluded Littl e Ar k an sas R ive r at Va ll ey Ce nte r , In d ian C reek at K an sas City, M isso u ri, S m ok y Hill Ri ve r at E lkad er , and D e laware R i ver near Ha lf Mound. Co nce n trations 

### in these water bo d ies ranged from 1

. 1 to 5.6 ug!L. The hi ghest detection in Iowa (0

. 53 u g/L) was at Boyer River near M i sso uri Valley. All of the moni toring concentrations i n the STORET data were less than the SWCC modeled EECs. T he USGS National Wate r Q ua l ity Assessme n t (NAWQA) Program also co n ta i ns p ropaz i ne moni toring data (http: //cida.usgs.gov/ nawqa

_ queries_public / jsp / mxmaster.jsp) and was acces sed on April 10 ,2 015. The NAWQA databa se has 1 , 733 record s from 16 states from the years 1992 to 2003 (Tab le 9).
15T b l 9 NAWQAP a e 

# . ropaz me om o rm g es u s 

### M 't . R I t State Year Total Records Detects Concentration Range (J..lg/L) AR 1996

- 1998 

### Ill 5 0.06

- 0.27 CT 1993 I 0 

## -- GA 1993 5 0 

## -- lA 1995

- 2003 523 38 0.04

- 0.36 

### I N 1991

- 1992 27 0 

## -- LA 1995

- 1997 91 7 0.05

- 0.85 

### MD 1 991 3 0


### -- MN 1 997

- 1998 39 0


### -- MO 1 996

- 1998 45 6 0.06

- 0. 1 9 

### M

S 1 995

- 1997 191 17 0.05

- 0.11 

### NE 1992

- 1 999 416 79 0.05

- 1.08 

### N

Y 1996

- 2000 13 0 

## -- OH 2002 3 0 

## -- TN 1996

- 1998 72 0


### -- WI 1 994 6 0 

## -- Data provided by the T exas Commiss io n on Environmen ta l Quality to the E P A for gro und water monitoring returned 493 results from the years 1 985 to 2013

. Seve n ty of t he sample s we r e detects with a range of 0.0 1 9 to 87.7 J..lg/L. The majority of propazine detection s in ground wate r over 1.0 J..lg/ L occ u rred after 2004. Data prov id ed by the State of Colorado to the EPA for monitoring returned 138 results from th e year 201 0. Four of the samp le s were de tec t s wi th a range of 0.021 to 0.5 J..lg/L with a detection limit of 0.02 J..lg/L. D a ta provid e d by the Washington State D epartment of Agricu l ture to th e EPA for monitoring re turned 3,244 res ult s from the years 2003 to 2012. Sixteen of th e samp les were greater than 0.05 1-lg/L with a ran ge of 0.05 to 0.25 J..lg/L. The S tate of Wisconsin also provided monitoring data to the EPA , r eturn in g 2,23 1 results for the years ra ng in g from 1999 to 20 1 1. Re su lt s ranged fro m 0.0075 to 635.2 1-lg/L, and detection limits were not reported. None of th e monitoring data listed above is a result of water sampli ng targeted to propazine use. That coup led with a less robust sampl e frequency wou ld suggest that the monitoring resul ts are m ost like ly missing the peak co nc e ntrati ons of propazi ne. Some detections of pro pazine appear to be outside of the typical so rgh um growing regions. It i s likely that some ground water detections were the result of spi ll s outside sorghum growing areas. F in all y, propazine was not registered for u se o n so rg hum until 2007, so any detections before that time may be due to previous, cancelled uses.

1 6Risk Characterization Thi s risk assessment was conducted primarily for the u se on sorghum. The labe led use for containerized greenhouse orname ntal s , if it is for outdoor use , would present a similar risk profile as the sorg hum use , for terrestrial organ isms. R egarding aq uatic organisms , it is unlikel y that propazine wou ld be used on outdoor ornamentals in an area as extensive as a co llection of so rghum fields. T hu s , the results of the sorghum risk assessment are likely to be p rotective of the ornamental use. Risk to Aquatic Organi sms For this assessment , parent-onl y EECs were calcu lated based on the sorghum modeling scenarios and the most sensitive of the ex is ting toxicity data by taxa. Based on th is preliminary assessment , using upper-bound ex po sure e s timates , there are no exceedances for aquatic animal taxa (Table 10). This inc lude s aquatic-phase amphibians , for which fish serve as surrogates. Wh il e th e r e are amphibian -spec ific data for atrazine w h ich indicate potential sub lethal effects at lo w exposure concentrations ( low ppb) , it is unclear to what d egree those data represent propazme. Tabl e 10. RQs for fi s h and aquatic invertebrates (ba se d on the most se ns iti ve e ndpoints)**~** 

### h

or prop az me u s e on sorg l um. Acute Chronic F is h In vertebrates Fish Invertebrates KS- Sorghum Aer i al Spray 0.007 < 0 .0 07 0.06 0.75 Ground Spray 0.006 < 0.006 0.06 0.68 TX

- Sorghum (OP) Aerial Spray 0.01 2 <0.012 0.07 0.89 Ground Spray 0.011 <0.011 0.07 0.85
There are no exceedances for non-listed aquatic vasc ular plants from the use on sorghum; howe ver , RQ s for listed aquatic vascular p lants exceed the LOC of 1. 0 by a factor of roughly two (Table 11 ). The RQs for non-listed nonvascular aquatic p l ants exceed the LOC by a lm ost a factor of two. RQs for li sted aq uatic nonvascular species exceed the LO C by almost 7

- fo1d , but the re are c urrently no aquatic nonvascular s pecies listed. B ecause there are no ESA

- listed aquatic nonvascular plants , no direct effects are anticipated. However , as with any direct effect to plants , indirect effects to other taxa a r e possible.

17

### T bl 11 

### RQ 

### t t h h 

### a e 

# . s or aquatic p . ants or t 

### e prop azme u se on**sor~l** 

### urn. Vascular No nvascular 

### Nonlisted Listed Nonlisted Listed KS

- Sorghum Aeria l Spray 0.36 

### 1.61 1.5 5.6 Ground Spray 0.32 

### 1.5 1.3 5.0 TX- Sorghum (OP) Aerial Spray 0.43 

### 1.9 1.7 6.6 Ground Spray 0.41 

### 1.8 1.6 6.3 1 Bold indicates exceedance of LOC It 

### is important to note that while endpoints from the guideline studies for propazine result in relatively marginal exceedances for nonvascular plants, data for atrazine in open literature s uggest that other species may be considerably more sensitive to chlorotriazines. To the exte nt that the same holds true for propazine , broad effects to aquatic communities of primary producers (phytoplankton) may be expected. For an in

- depth discus s ion of these potential impacts , p l ease see the atrazine draft eco logical risk assessment (atraz ine docket

- EPA

- HQOPP-20 13-0266). 

### Risk 

### to Terrestrial Organisms It 

### is important to note that the ri sks identified here , as indicated by RQs re lativ e to the LOCs , are based on the mos t sensitive endpoints and upper-b ound exposure scena rio s . If it becomes useful for risk management to provide refmements to these risk estimate s (beyo nd those in the Section 3 New Use assessment , DP Barcodes 0310326 , 0249944 , 0249945 , 11103/06), they can be provided. Despite the avian acute lethality endpoints being non-definitive (i.e

. greater than) values, sublethal effects on body weight were observed in the studies . Therefore , for frame of reference , RQ-values were calcu lated using the highest concentrations tested. The highest RQ- value is 0.28 , which would exceed the listed spec ies LOC. However, g iven that this RQ is based on sub lethal effects and not a frank LD so, acute risk to avian species is expected to be )ow. Additionally, a recently submitted passerine subacute dietary study (descr ibed previous ly) which resulted in a frank endpoint is used provisionally. A dietary study was conducted based on regurgitation observed in the range-finding study. This study was submitted in lieu of the g uidelin e acute oral study with passerines based on EFED Guidance (Brady 20 14) : " Gu id ance for Reviewing OCSPP 850.2100 Av ian Oral Toxicit y Studies Conducted with Passerine Bird s". Like the other avian studies , weight lo ss was noted as a subletha l effec t at all test concentrations, though recovery was ultimately noted in the lowest concentration. Based on the LCso 

### = 2837 mg ailkg-diet, the hi ghes t dietary

- based RQ is 0.1 , which i s exactly at th e listed species LOC. The study authors provided a conversion to a dose (L D so 329 mg ai/kg-bw) , which is used here for characterization purposes only, as there is low confidence in such a conversion. Using this ' dose ', the hi g he st RQ-value wou ld be 1.38 , almost three times the nonlisted LOC. However, thi s study 18is under review and, again, these values are reported here provisionally. Consistent with the sub lethal effects on weight noted in the acute studies, effects on weight were noted in the avian reproduction studies. Given the lack of a NOAEC, risk to birds from chronic exposure cannot be reliably estima ted. Us ing the LOAEC from the available bobwhite study (262 mg ai!kg-diet), the dietary RQ-valu e for chron ic exposure to birds i s 1

. 1 , marginally exceeding the LOC. A frank no-effect value from the requested study (Registration Review data call-in) would resu lt in a greater exceedance of unknown magnitude. As a point of reference , s im az ine ' s bobwhite NOAEC is 100 mg ailkg-diet (MRID 00163134). If that endpoint were rele vant to propazine, the highest RQ wou ld be 2.88. Prop azine has no known ac ute effect on m am mal s, and the likelihood of acute risk is considered to be low. However, decrea sed body weights were observed on both parenta l and reproductive endpoints in the three-generation rat study. Based on these effects, 

### mamm a li an chronic RQ s excee d the LOC b y factors up to 25 -fol d. These exceedances are based on on-fie ld exposure estimates; off-field exposure , particularl y from spray drift has not been exp lored for this assess me nt. No effects on honeybees were observed in the available acute contact study , and therefore no RQ s are ca l culated. However, as described previously, the full suite of pollinator toxicity studies are not available fo r propazine. As expected with an herbicide, RQs exceed the LOC for se n sit ive plant species. The RQs reported in Tab l e 12 reflect the most sens itive spec ies from the available s tudie s (see Table 4). Given the spray drift RQ resulting from the screening level model TerrPlant are roughly equivalent to 200 feet off the site of application (based on comparison to AgDRJFT defaults) , effects to sensitive terrestrial plants , particularly listed species , should be expected well off the site of application. As reported in Table 1 3 , exceedances from ground sp ray application are considerably reduced. A refinement utilizing the AgDRlFT mode l could exp lore the distances off field for which effects are expected for each species tested, but given the sensitivities across species (see Table 5) , these distances should be expected generally consistent across sensitive species. 

### Tab le 12

. Maximum expected terrestrial pl a nt RQ s for the u se on sorghum (aerial application)

. 

## I Plant**T~ee** 

## I Listed Status 

# I Dry 

# I Sem i-Ag uatic 

# I**sera~** Drift Monocot non-listed 2

. 06 5.14 1

. 71 Monocot listed 8.28 20

. 69 6

. 90

Dicot non-listed 4.50 11.25 3.75 D icot l isted 1 5

. 32 38.30 12.77 I * If RQ > 1.0 , the LOC is exceeded, res ulting in potential for r isk to that plant group.

19 

# I

### Tabl e 13. M ax imum expected terrestri a l pl a nt RQs for th e u se on sorghum (ground a pplication ). Plant Type Listed Status Dry Semi-Aquatic Spray Drift

Monocot non-listed 0.69 3.77 0.34 Monocot listed 2.76 15.17 1.38

Dicot non-listed 1

. 50 8.25 0.75 Dicot listed 5

. 11 28

. 09 2.55

* If RQ > 1.0, the LOC is exceeded, resulting in potential for risk to that plant group . EPA ge ne rally u ses a 25% inhibition i n growth, ei th er b iomass or he ight , to assess potential ri s k to pl ant spec ies . A population of plants that experience a 25% or g r eater inhibition in g ro wth early in the growing seaso n may recover , depending o n th e plant , but this leve l of effect may have l asting consequences on the affected plant s. Pl ants w hose growth is interrupted during their act iv e growth period may not recover. P lants may be insufficiently competitive for resource s, s uc h as sun l ight or water, due to thei r decreased growth. Ear ly season interruption in growth may a lso result in fewer absolute seed numbers or in numbers of v iable seed 

### (i.e. reproducti ve effects). In comm uniti es whe re propazine exposures occur, relative l y insensitive species may outcompete sensitive species , leading to shifts in comm uni ty compos it ion and subsequentl y shifts in community function. Such changes may result in a cascade of ecological effects on higher order spec ies and/or edaphic functionali ty (suc h as decreased interception of excess nutrients). The plants used in g uid eline testing are generally crop s pecies selected specifically for their ease of husbandry in laboratory settings. As a rule, it is best to consider eac h species teste d as representative of a potential sensitivity in the universe of p lants that may be expose d , such that se n si tivity of, for example , soy bean represents not onl y soybean , but plant s with a sensitiv i ty s imil ar to soybean. What those s pec ies of sim il ar sens itivity are is not usually known. F urth er , to what degree th e spec ies chosen for testing are representative of the range in pote nti a l plant se n s itiviti es found in the general ecosystem is uncertain. Not ju st p lant species are likely to be affected; plant biodiversity provides a number of ecosystem services, including providing habitat for pollinators and beneficial insect predators. Recently , a g r eat deal of research has been directed at the effect of plant diversity and associated insect populations (Freemark and Boutine , 1995; Isaacs e t a/. 2009; Mortensen et al., 2012. No rri s and Kogan, 2000; Norris and Kogan, 2005). S i mi lar disruptions in habitat or food sources may occur fo r highe r order animals (e.g. birds and mammals) in areas proximal to use s ites. As changes in plant communities occur due to differences in species sensitivity, subsequent loss of preferred feed or shelter for animals can be expected. In this way, animals can be affec ted by use of these herbicides. Affected animals might be at any trophic l evel, and may particularl y affect organisms with obligate relationships to spec ific plant spec ie s.



### Incid e nts The eco lo g i ca l incid e nt information system (EllS) is an OPP database that houses eco l ogical incid e nt s that have been reported to the Agency. Whe n availab le, EII S inclu des date and 20location of an incident, type and magnitude of effects observed in vario u s s p ec ies , use(s) of pesticides known or suspected of contributing to the incident , and results of any chemical re s idu e analysis or other analyses conducted during incident investigation. EIIS incidents are categorized according to the certainty that the incident resulted from pesticid e exposure. The Avian Monitoring System (AIMS) is a database administered by the American Bird Conservancy t h at contains pub l icly avai lable data on reported av ian incidents involving pesticides. Many of the inc idents listed in this database are also in the Ell S. As of September 20 1 5 , there are no reported incidents for propazine in the EllS database. Th e re are also no incidents report ed in the AIMS database nor are there any aggregate incidents reported. The absence of reported incidents should not be construed as the absence of inc idents. I nc ident report s for non-target organisms typically provide inform ation only on mortality events and plant dama ge. Sublethal effect s in organisms such as abnormal b e havior , reduc ed growth and/or impaired reproduction are rarely reported , exce pt for phytotoxic effects in terres trial plants. 

### F e d e rall y Thre aten ed afld Efldan g ered (L is te d) Sp e cies Con cem s In November 2013, the EPA , along with the U.S. Fish & Wi ldlife Service (USFWS), the National Marine Fisheries Service (NMFS) (collectively , the Services) , and the U.S. Departme nt of Agriculture (USDA) re leased a summary of the ir joint Interi m Approaches for assessing risks to listed s pecies from pesticides. The Interim Approaches were developed jointly by the age nc ies in response to the National Academy of Sc ie nces ' (NAS) recommendations and reflect a common approach to ri s k assessment s h ared by the agenci es as a way of addressing scientific difference s between the EPA and the Services. The NAS r e port outlines recomm e ndations on specific scientific and technical issues rel ate d to the deve lopment of pesticide ri sk assessments that EPA and the Services must conduct in connection with their obligations under the Endangered Species Act (ESA) and F IFRA. The joint Interim Approaches were re leased prior to a stakeholder workshop held on November 15 , 2013. In addition , the EPA presented the joint Interim Approaches at the December 2013 Pesticide Program Dialogu e Committee ( PPDC) and State-F IFRA Issues Re search and Evaluation Group (SFIREG) meetings , and held a stakeholder workshop in April2014 , allowing additiona l opportunities for stakeholders to comment on the Interim Approaches. As part of a phased , iterative process for deve loping the Interim Approac hes, the agencies w ill also consider public comments on the Interi m Approach es i n connection w i th the development of upcoming Registration Review deci s ion s. The details of the joint Interim Approaches are contained in the wh ite paper " Interim Approaches for National-Level Pesticide Endangered Species Act Assessments Based on the Recommendations of the National Academy of Sciences April 2013 Report, " dated November 1 , 2013. Given that the agencies are continuing to deve lop and work toward implementation of the Interim Approaches to assess the potential risks of pesticides to listed species and their designated critical habit at , this preliminary risk assessment for propazine does not contain a complete ESA analysis that includes effects determinations for specific listed spec ies or
21designated critical habitat. Although EPA has not ye t completed effects determinations for specific spec ies or habitats , for this preliminary assessment EPA conducted a brief screeninglevel assessment for all taxa of non - target wildlife and plant s that assumes for the sake ofthe assessment that listed species and designated critica l habitats may be present in the vicinity of the application of propazine. This screening level assessment w ill allow EPA to focus its future evaluations on the types of species where the potential for effects exists once the scientific m eth ods being developed by the agencies have been fully vetted. This screening-level risk assessment for propazine in dicates potential risks of direct effects to listed birds , mammals , and terre str ial plants when used on sorghum. Listed species of bird s, mammals , and terrestrial plants may also be affected through indirect effects because of the potential for direct effects on li sted and non-listed species upon whic h suc h spec i es may rely. Potential direct effects on li sted birds , mammals , and terrestrial plants from the use of propazine may be associated w i th modification of Primary Constituent Elements (PCEs) of designated critical habitats, where suc h designations have been made. Once the agencies have fully developed and impl e mented the scientific methods nece ssary to complete risk assessments for endangered and threatened (listed) species and their designated critical habitats , these methods will be applied to s ubsequent analyses for propazine as part of completing this registration review. 

### Endo crin e Disruptor Screening Program (EDSP) As requi red by FIFRA and the Federal Food, Drug , and Cosmetic Act (FFDCA), EPA re views numerous stud ie s to assess potential adverse outcomes from expos ure to chemicals. Collectively, these studies includ e acute, subchronic and chronic toxicity , including assessments of carcinogenicity, neurotoxicity , developmental , reproducti ve , and general or systemic toxicity. These stu di es include endpoints which may be susceptib le to endocrine influence, including effects on endoc rine target organ histopathology , organ weights , estr u s cyclicity , sexual maturation , fertility , p regnancy rates , reproductive loss , and sex ratio s in offspring. For ecological hazard assessments , EPA evaluates acute tests and chronic studies that assess growth, developmental and reproductive effects in different taxonomic groups. As part of the Problem Formulation for Registration Review (0407225; May, 2013), EPA revi ewed these data and selected the most sensitive endpoints for re levant risk assessment scenarios from the existing hazard database. H owever, as r equired by FFDCA section 408(p) , propazine is subject to the endocrine scree nin g part of the Endocrine Disrupter Screening Pro gram (EDSP). EPA has developed the EDSP to determine whether certain s ub stances ( including pesticide active and ot her ingredients) may have an effect i n humans or wildlife similar to an effect p roduced by a "naturall y occ urrin g estrogen , or other such e ndocrin e effects as the Administrator may designate. " Th e EDSP employs a two-tiered approach to making the statutorily required determinations. Tier 1 consists of a battery of II sc reenin g assays to identify the potential of a chemica l substance to interact with the estrogen , androgen , o r thyroid (E, A, or T) hormonal syste m s . Chemicals that go through Tier 1 screening and are found to have the potential to interact with E , A , o r T hormonal syste ms will proceed to the next stage of the EDSP where EPA will determine which , i f any , of the Tier 2 tests are necessary based on the available data. Tier 2 testing is designed to id e ntify any adverse endocrine-related effects caused by the substance, and establish a dose-response re la tionship between the do se and th eE , A , or T effect.

22Under FFDCA section 408(p), the Agency must screen all pesticide chemicals. Between October 2009 and February 2010, EPA issued test orders/ data ca ll-ins for the first g roup of 67 chemicals , which contains 58 pesticide active ingredients and 9 inert ingredients. A second li st of chemicals identified for EDSP screening was published on June 14, 2013[1] and includes some pesticides scheduled for registration review and chemicals found in water. Neither of these li sts should be construed as a list of known or likely endocrine disrupters. Propazine is not on List 1. For further information on the status of the EDSP , the po li cies and procedures , the lists of chemicals , future lists , the test guidelines and Tier 1 screening battery , please visit our website[2]

.

[I) See hnp: //ww w. re gul a ti o n s. g ov /# ! documentDet a ii ;D

- E PA-1-10- 0 PP T

-200 9- 0477

- 0074 for the fmal s econd li s t of chemicals

. [2] Available: http ://www. e pa . go v / e ndo /
23

### References: Freemark, K. , and C. Boutin. 1995. Impacts of agricultural herbicide use on terrestrial wildlife in temperate landscapes

- a review with special reference to North-America. Agric. Ecosys t. E nviron. 52 , 67

- 91. Isaacs , R. , Tuell , J. , F iedler, A., Gardiner, M. , Landis, D. , 2009

. Maximizing arthropod

- mediated ecosystem services in agricultural landscapes: the role of native plants. Front. Ec ol. Environ. 7 , 196-203. Mortensen , D.A. , Egan, J.F. , Maxwell, B.D. , Ryan , M.R., Smith, R.G

. , 2012. Navigating a critical junc ture fo r sustainable weed management. Bioscience 62, 75-85.Norris, R.F., Kogan , M. , 2000

. Interac tions between weeds, arthropod pests , and their natural enemies in managed ecosystems. Weed Sci. 48, 94

- 158. Norris, R
. F. , Kogan , M
. , 2000. Interactions between weeds, arthropod pests , and their natural enemies in managed ecosystems. Weed Sci. 48,94

- 158. N orris, R.F. , Kogan, M., 2005. Ecology of interactions between weeds and arthropods

. Annu. Rev. Entomol. 50 , 479-503. USEPA 2006. Ecological Risk Assessment for the Section 3 New Use on Sorghum: Propazine. DP barcodes 310326, 249944, 249945. United States Environm e ntal Protection Agency, Office ofPesticide Programs, Washington, DC. U S EPA 2013. Registration Review: Problem Formulation for Environmental Fate and Ec ological Risk , Endangered Species , and Drinking Water Assessments for Propazine (Case 230). DP Barcode D407225. U nited States Environmental Protection Agency, O ffice of Pesticide Programs , Washington, DC.

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### 25