UNITED S TATES ENVIRONMENTAL PROTECTION AGEN CY

OFFICE OF CHEMICAL SAFETY ANO POLLUTION PREVENTION PC Code: 122101 DP Ba r co d e: 423648 May 27, 2 0 15 MEM O RANDUM 

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### TO: Drinking Water Assessment for Propo se d New Uses of Propiconazo le on Dill, Radish , Leafy Bra ssica Subgroup 

### SB, Wate rcress , Ti palm and Crop Group conversions for Stone Fruit Group 12-12 and Tree Nut Group 14-12. Ibrahim Abdel-Saheb, Ph . D , Environmental Scientist , -

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# T / / f Environmental Ri sk Branch 

### VJ Environmental Fate and Effects Division (7507P) {' (/ Mark Corbin, Branch Chief . 

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- \) Willi.am P.

# ~ckel, Ph.D ., Senior

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# J . - Monica Wait, RAPL /**!/£/~** 

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## 7**/~** Environmental Ri sk Branch 

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## 5. Environmental Fate and Effec ts Division (7507P) 

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## 5 Thurston Morton , Risk Assessor RAB4 Hea lth Effects Di vis ion (7509P) Driss Benmhend, Risk Manager Reviewer Shaja Joyner, Prod uc t Manager Team 20 Fung ic ide-Herb ic ide Branch Registration Divisi o n (7505 P) Sidney Jackson, Ri s k Manager Reviewer Barbara Madden , Minor Use Team Leader Product Manager 5 Minor Use and Emergency Respons e Branch Registration Divi sio n (7505 P) Thi s memorandum provides estimates of human drinking water exposure to propicona zole (a broad spectrum fungicide for contro l of plant , turf and ornamental d i seases) from the proposed new uses on dill, radish, leafy brass ica subgroup SB, watercress, Ti pa lm and crop group conversionsfor Stone Fruit Group 12-12 and T ree Nu t Gro up 14 -1 2. Note th at this assess ment incorporates new model s implem e nted s in ce the previous EDWC and th e refo r e a co mp a r i so n of E D WCs are s h own in Table I be low. Mod e l inputs a nd outputs are includ ed in A pp e ndix I Thus , EFED re commends th at the Hea lth E ffects Division use the fo ll ow in g s ur face wa ter and groun d water E DW Cs ( hi g hli g ht e d field s ) resu ltin g from modeling. Pl ease not e that whi le the surface wa ter EDWC h ave decrease d a nd th e gro und water E DWC have incre ased s in ce th e 2006 drinking water assessmen t (w hi c h i s the so urce of pre v i o u s hi g h EDWC) th e overa ll reco mmende d EDWC for g r o undw a te r a re s till lowe r than those previou s ly r eco mm e nd ed for ri sk assessment. . Tab l e 

### l. Est imat ed Drinkin g Water Concentrations (EDWCs) for propo s ed n ew u ses and prev iou s ly r eg i s ter e d turf. 

### Use on Turf S ur face water S urfa ce water 2006 Mode lin g 2015 Modeling (PRZM / EXAMS) * (SWCC)* * Dill Peak (ppb) 76.5 Peak (I
- in- I 0 35.2 2 . 84 y r) Annual Mean (ppb) 37 . 5 365
- day Avg 18. 6 1.35 ( I
- in- I0 yr) 30 -Y ear Mean (ppb) 26.4 Entire 14.4 1.04 S im ulation Mean**~** SC I
- PRZM-GW *** Gro undw ate r G R OW EDWCs ( ppb ) Pea k 37.9 1. 84 Concen trati on (oob ) Pos t- jS, I 1. 66 0.64 Breakthro ug h M

ean Conce ntrati on ( ppb ) Entire 26.4 1.25 Simulation Mean Co nc e ntrati on (o ob ) •B ased on PA turf sccnan o (lu ghc st m o del o utput ) • • Two scenari os "ere run and hi g he s t model o utput is presented in thi s table . Fo r the S WCC mo del : the foll o wing a vailable turf s cenari os were used · F

L. and PA The Penn sy lvania s ccnnri o gave the high est EDWCs . ••• F o r th e PR Z i\1 -G W m o del : 1hc fo ll owing available scenari o s "er e us ed : 

### New Uses S urf ace water 20 1 5 Modeling (SWCC) Radi sh Wmcrcrcs s Ti Pa lm

18.4 15.9 8.69 2.68 3.65 2.25 1.76 2.61 1.69 PRZM-GW 2.47 2.47 2 .47 2.23 ? ?" 

# -·-"' 2.23

1. 67 1.6 7 1.67

Fl.potai o. Fl. c itru s. GA coa s wl. and NCcoas ial . and Wlsand . The Wl s and sc enario gave lh c hi ghes t EDWCs .

2 S t o ne Fruit ( 12- 12 ) 3.55 1.61 1.35

3. 17 2.85

2.14 T ree Nut ( 14
- 1 2) 4.88 2.68 2.36

4.4 1 3.99

2.99

### The propiconazole end-use products associated with the proposed new uses are Quilt (EPA R eg No . I 00-1178) ; Ins pire ® XT (EPA Re g No. 100
- 1 3 12); Tilt (E PA Reg No. I 00-617); and Qui lt Xcel ® (E PA R eg No. 1 00- 1 324). These produ c ts ma y be applied by gro und , a ir , o r chemigat io n. T he proposed u se rates a re tabu lated be low ba se d o n th e s ubmitted lab e ls . T he tree nuts use s ite (s ub gro up I 4
- 12) has th e hi ghe s t proposed maximum s ing le application rate (0 .2 25 lb a.i ./ A) and the hi g he st an nu a l application rate (0 .9 0 lb a. i ./A) of th e proposed uses. C r o p Use Ra t e ( l b No. A pp Tot a l Use Data S ourc e a.i./A) (Inte rv a l R ate/ Sea s on ( l b in d ays ) a.i./A) 

### Dill 0.1 1 25 3 (7- 10) 0.34 EPA Reg. No. 100- 6 17 , - 1178 , - 1324 Radi s h 0. 112 5 4 (7- 10) 0.45 EPA Reg. No. 1 00-617 , - Watercress 1178 , -1324

Ti Pa lm S tone Fruit ( 12- 12) 0 .1 125 5 ( 10-14) 0.56 EPA Reg. No. 100
- 6 17 , - 1178 , -1312 , - 13 24 T ree Nut (14- 12) 0 . 225 4 (7- 1 4) 0.90 E PA Reg. No. 100-617 , - 1 1 78 , - 1324,- 13 12 

# Phys ical/ Ch e mic a l /F ate and Tr an sport Prop er ti es Propiconazo le i s a n amber to ye ll ow v isco us li quid with a boili ng point of 95 "C, dens i ty of 1 .2 7 g/ cm3 , oc tano l /wa te r part it ion coeffic i ent (log 

### K aw) of 2.95, a nd vapor pressu re of 1.0 x Io6 Torr at 20 ° C. Propi co n azole is s lightly so lubl e in water ( 100 ppm at 20 ° C) , p ract ica ll y in so lubl e in hexane (0.06 ppm), and is mi sc ib le w ith mos t organic so lve nt s, including methan o l , isopropanol , acetone , methylene chloride , toluene, and n- oc tan o l. Propiconazole appears t o be persiste n t and moderately mobi le to relative imm ob il e in mos t so il e nv ironment s. In th e aquatic e nv ironm e nt , propiconazole degradation appears to be dependent so le ly o n aqueous ph oto lys is in the pre se nc e of photo se ns itizers. In so il e n v ironment , propiconazo le dis s ipation appears to dep e nd on in co rporation or bindin g t o so il organ ic matter content. Laborato ry and terrestrial field di ss ipati o n data indic at e th at propiconazo le is s t able in so i l and aq ueo u s environments. Howeve r , in s uppl emental aqua tic di ss ip ati on data u s in g basin
- irrigati on and flow through irri gat i on sys t ems in rice field s, propieonazole was found to be dissipated rapid ly (t 1 12 < 

### 5 days ) . Aqueous photolysis studies using se nsitizers indi cat ed rapid d egradatio n (t 1 12 < 

### 1 days) o f propiconazole , wh ich appears t o be the case in ric e fi e ld s. Furth ermore , aquatic 3metabolism and dissipation s tudi es i ndicate prop i conazo le dissipates by in co rporation or binding into the organic matter co nte nt of soil/sedime nt. P ropiconazole mobilit y in so il a ppears to be dependent on the soi l' s orga ni c matt e r content. In ge ner a l, propicona zo le a ppear s to be m o d erate ly m o bile 

### ( Kd < 5) in so il s with a low organic matter content(< 1 %). H oweve r , in soils w ith hi g h e r o rganic m atte r content(> I %) , prop ic o nazo le ap p ears t o be r elative l y imm obi le 

### ( K d > 5) . Therefore , prop ico n azo le ma y reac h gro und wate r in soils wi th low o rgani c contents. Propiconazole may a l so conta minate s ur face wa ter thro u g h o ff- s ite run off a nd s pray drift. 

# Modeling In th e case of prop ica n azo le , turf , a pre v i ous ly reg i ste re d us e, ha s th e hi g h es t a pplication rat e of a ll cuITent ly registered u ses ( 7.2 l b a.i./A/Year, 4 app li catio n s of 1.78 lb a. i ./A w ith a 14-day interva l be t wee n applica ti o n s) (d rinking water asses s m ent, DP 323440, 617 / 2006). Thu s, turfrepresents th e m os t co n se rva ti ve mod e ling scenario for propico n azole. T h e Tier 2 ( PRZM- EXA MS) m ode l s we r e u sed in th e 2006 drinkin g wa ter assess ment ( OW A) c ited above and res ult ed in th e fo llowing es tim a ted drinking water concent rat ions (E DW Cs) for s urface water: 76 .5 ppb p ea k expos ur e, 37.5 ppb annua l mean. For g roundw ate r , the m ode l SCIG ROW gave acute and chronic EDWCs of 0. 64 ppb. S in ce 2006, EFED ha s introduced ne w surface water a nd g rou nd wate r m o d e l s [i.e S urfac e Water Co ncentration Calculato r (SWCC), and PRZM-GW , respec ti ve ly ] . A compa ri so n was mad e between output from curre nt E FED mod e l s for propiconazole fo r th e prop ose d uses o n dill , rad i s h , le afy brassica S u bg ro up 5B (0.34 lb a. i ./ A/seaso n); radish , wa te rcress, and T i palm (0.45 lb a.i./A / seaso n); crop group co n vers io n s fo r Stone Fruit Group 12- 12 (0 .56 lb a .i ./A/s eason); Tree Nut Group 14-12 (0.90 lb a .i ./A / seaso n) with the output from the currently reg i s tered u se on tu r f (4 applicat io n s of0.786 lb a .i . ./A per year with a 14-day interval b etween a pplication s) . F o r watercress modeling , s in ce proposed labels (EPA R eg . No. 1 00 -1178 , E P A R eg . No . 100-1324 ) indi ca te that propico n azo le ap pli cati o n i s to be durin g n o n-flooded period , n o a quatic modeling was n ee ded. App lic ation date s for the prop osed uses we re based o n in fo rm atio n from th e p roposed labe l s (E P A Reg . Nos. 1 00-617 , 1 00 -1178 , 1 00 -1 312. 1 00 -1 324). Pl ease n ote that the s urface EDWCs reproduced from th e previous 2006 OWA mode ling o n turf a r

e hi g her than those generated b y the currently u se d m ode l. This difference co uld b e attributed to the u se of diff e re nt input p aram ete rs. In the 2006 OWA, The default P C/\ o f 0.87 was u sed vs. 0.45 ( the high es t s ta te PCA val u e for turf). In a ddition , in the 2006 OWA, S pray Drift Fraction was ass um e d to be 0.16% vs. 0. 1 3 5 % in th e 20 1 5 mod e ling run.

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# A p pe n dix I SWCC Mode l PA Turf Table 1. Estimated Environmental Concentrations (ppb) for propiconazol e.

Peak (1-in-10 yr) 35 . 2 4 - day Avg (1-in-10 yr) 34 . 7 21 - day Avg (1-in-10 yr) 32 . 9 60-day Avg (1-in-10 yr) 30 . 3 365-day Avg (1-in-10 yr) 18 . 6 Entire Simulation Mean 14 . 4 Table 2. Summary of Mode l I nputs fo r propiconazo l e.

Scenario PAturfSTD Cropped Area Fraction 0.45 Koc ( ml/g) 648 Water Half-Life (days) @ 25 ° C 138.4 Benthic Half-Life (days) @ 25 °C 363 Photo l ysis Half-Life {days) @ 40 °Lat 0 Hydrolysis Half- Life (days) 0 Soil Half-Life (days) @ 22 ° C 69.2 Foliar Half- Life {days) 35 Molecular Wt 342 . 33 Vapor Pressure (torr) 1E-6 So l ubi l ity (mg/I) 100

5Table 3. Applic ation Schedule for propicon a zol e . Date (Mon/Day) Type Amount (kg/ha) Eff. D ri ft 4/1 F olia r 2 0 . 95 0 . 135 4/15 Foliar 2 0.95 0 . 135 4/29 Foliar 2 0 . 95 0 . 135 5/13 Fo l iar 2 0.95 0 . 135



### PR ZM G W M o d e l Tabl e 1. Ground w ater Re sults for P r opiconazol e Turf and th e Wisconsin Corn - WI Central Sands Scena r io .

Peak Concentration (ppb) Post - Breakthrough Mean Concent r ation (ppb} Entire Simula t ion Mean Concentration {ppb) Average Breakthrough Time (days) Throughputs 3 7 . 9 3 5 . 1 2 6 . 4 10455.14 3 .4 58776 Table 2. Ch e mical Prop e rties for Groundwater Modelin g of Propiconazole Turf.

Koc (ml/g) 604 Surface So i l Half Life (days) 5 3 Hydrolysis Half Life (days) 0 Diffusion C oefficint Ai r (cm2/day) 0.0 Henry ' s Cons t ant 0 . 0 En t ha l py (kcal/mol) 0.0

6Ta b le 3. Pest i ci de a pp l i cat ion scheme used fo r Prop ic o naz ole Turf . Thi s a ppl ica tion scheme wa s app l ied every yea r of th e si mu l at i o n.

Application Date Application Method Application Rate (Month/Day) (kg/ha) 

### 4/1 Above canopy application 0.88 

### 4/15 Above canopy application 0.88 

### 4/29 Above canopy application 0 . 88 

### 5/13 Above canopy app l ication 0.88 

### 5/27 Above canopy app li cation 0.88 

### 6/11 Abo v e canopy a pp l i cation 0.88 

### 6/25 Above canopy application 0.88 

### 7/9 Above canopy application 0.88

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