### UNITED STATES ENVIRONMENTAL PROTECTION AGENCY WASHINGTON , D

. C. 20460

MEMORANDUM Date: Se pt e mber 15 , 2015 OF FI CE O F CHEMICAL SAF E TY AND POLL UTI O N P R EV E NT I O N



### SUBJECT: Di croto pho s: Res p o n se t o C omm e nt s o n th e Human H ea lth Ri s k Assess m e n t fo r Regi s tratio n Review of Dicro t op hos. PC C od e: 035201 Deci s ion No
. : 49 7 854 P e t i tion No. : NA Ri s k A ssess m e nt T y p e: Human He alth R i s k A sses sment T XR No. : NA MRID No .: NA 

### FROM: T hur s t o n G. M o rto n , C he mi s t , RAB IV Wa de Bri tto n , B io log i st , RAB IV H ea lth Effec t s Di v i s i o n ( 7 509 P ) DP Barcode: 4242 9 2 R eg i s t ratio n No
. : NA R e g ulat or y Act i on: Reg Review Ca s e No.: 0 1 45 CAS N o.: 14 1-66-2 40 FR: §I 8 0.299

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THROUGH: Char les Sm ith , Branc h C hi ef

## D~ Ri s k Assess m e nt Bran c h IV H ea lth Effec t s Di v i s ion ( 7 5 0 9 P) TO: Khu e Ng u ye n a nd Ne il Ande r so n Ri sk Man age m e n t and lmpl e m e nta ti o n Bran c h 1 P est ici de Re - Eva lu atio n D iv i s io n (PRD ) ( 7 508 P )

Page 1 of 4AMVA C's R es ponse to EPA's Preliminary Drinking Water E xpo s ure and Acute and Steady State Aggregate Di etary Ri s k Assessments for Dicrotopbo s ./. 1.2 EPA memorandum of July 10 , 20 14 : (PC Code: 035201,· DP BarcodeD418103); "Dicrotophos: Acute and Steady State Aggregate Dietmy (Foo d and Drinking Water Expos ure and Ris k Assessments to Support Regis tr atio n R ev iew" , by Thurston Morton (Chemist) Risk Assessm e nt Branch IV. Health Effects D h i i s ion (7509 ? ). I. Within the "Executive Summary" section, "Steady State Diet ary (Food and Drinking Water) Ex po s ure r es ults and C haracteri za tion' ', 2nd pp ., EP A s tate s, "A n unrefined steady s tate dietary exposure a ssess ment wa s conducted to estimate the dietary ri s ks a ssoc iated with the r eg i stration of dicrotopho s. Th e s tead y state dietary expos u re assessment incorp ora ted tolerance l eve l residues and I 00% cro p treated. The steady state aggregate dietary exposure estimates from Calendex are above R ED's l evel of concern(> I 00% of the PAD) for th e U.S. population and all pop ulati on s u bgroups. Combined dietary exposure from fo o d and drinking water is 136 % of the PAD for the U.S. population and 358% of the PAD for c hildren 1- 2 yea r s, the m os t high l y exposed population s ubgroup." AMVAC's comment: We hav e a lread y confirmed with EPA that the se values are in err o r and th e highest exposed s ubpopu l ation gro up i s th e all infant s (< I yea r o l d). Th e combined dietary expo s ure from food and drinking wate r a t the 95 th percentile for the U .S
. popu l ation ran ges from 66 to 92% of the PAD , which does not exceed R ED's l eve l of concer n . The comb in ed d i etary ex po s ure from food and drinking water at the 95•h percentile for the all infants (< I year old) population s ubgro up ranges fr o m 120 to 210% of the PAD , wh ich exceed RED' s l eve l of co ncern. As EPA has indicated , th ese exceedances r es ult in a slight overestimation of exposure as the assessment ass ume s tolerance level residue s and I 00 % crop treated. Al so, water expos ure is based o n a sc r een in g level assessment of surface wate r exposure usin g PRZMI E XAMS that can be refined a s indicated prev i ous l y in th i s document. H E D Response : Thi s error will be corrected in th e revi se d di etary ex p osu r e assessme nt memorandum. 2. Within the "IV. Drinking Water Data" section , I s t pp ., EPA s tates , "This asses s ment uses maximum rat es but conside rs typ ical rates though monit o ring data exceeds the re s ultin g EDWCs in so me instances." AMVA C's comment : Th e onl y EDWC exceedance of which we are aware is the s ingle NA WQA sa mple finding of 6.83 ppb out o f a databa se of 8, 500 sa mple s. These findi ngs, espec i a ll y when c o n s idered o n the ba s is a s tatistical di str ibution would indicate that the PAD would not be exceeded o r at most o nl y at a probabilistic leve l exceed ing the 99 .9 1 " percenti l e. HED R es pon se: Th is com m ent is un de r the pu rv i ew of EFED. 3. With in the " I V. Drinkin g Wat er Data " section , I s t pp ., EPA states, "T he asse ss ment considers a parent only approach but also con s iders the major d egradates as parent in a total toxic re s idue (T RR) approach." AMVAC's comment: Within our comments to the EPA memorandum of Jul y I 0 , 2014: ( PC Code: 035201; DP Barcod e 393772); "D icrotophos: Drinking Water Assessme nt for R eregistration R ev iew "
. by Andrew S helby (P h ysica l Sc ienti s t) Environmental Ri sk Branch 6 , we exp l a ined o ur views for propo s in g that th e total tox ic re s idu e definition be redefined to exclude metabolit es/degradate s that do no t maintain an organop hosp hat e based s tructura l functionality
. On thi s basi s, the EDW C exceeda ncc s over state exposure. H E D R es pon se: Thi s comment is under the purview of EFED
. Page 2 of 44
. Wit hi n the ''Drin king Water Data" sec ti o n, I s t pp ., EP A s tate s, "G ive n curr ent unc er tainty , he following degradate s are included in the lT R approach:" AMV AC's comment : The refere nc ed infonnation is not pro v id e d. HED Re s pon se: Thi s erro r will be co rre cted in th e r evised diet ary exposu r e assess m e n t memorandum. 5. Within the "VI. CA LEN DEX-D C ID Pro gram " section, 2 nd pp ., EP A states, " R ED's stea dy sta t e assessment co n s id er s the potenti a l ri sk fr om a 21- day ex pos ure duration us in g a 3-week ro ll ing average (s liding by day) across th e yea r. For this assessment , the sa m e food res id ue va lues used in th e ac ut e assessme n t we r e u sed for the 2 1-da y durat i o n. I n the Ca l e nd ex, o ne diary for each indi v idu a l in the WWEIA is se l ected to be pair ed w ith a randoml y se l ec t ed se t of residue valu es fo r eac h food co ns um ed. For the wate r resid ue va lu es, Ca lend ex in corpo rates P RZM-EXAMs drinking wa t e r re s idue by se l ect in g a yea r at r ando m from th ose ava ilabl e in the desig nated d rin ki n g wa t er r es i du e fil e." AMVAC's comment: Althoug h t he process bein g use d by RED r e pr ese nts a reaso n ab l e ini ti a l sc r ee nin g approach. the avai l ability of a l arge s ur face wate r m o nit ori ng d atabase that inc lu des targeted sa mplin g provides a n opport uni ty for r e fining th e wate r ex po s ure ba se d a nd ag g r egate ri sk assess m e nt s. 

### H E D Response : This com m e nt is unde r th e pu rview of EF ED. 6. Within the "V III. Re s ults/Disc u ss io n " sec ti on , 2nd pp ., EP A s tate s, "For foo d and d rinkin g wate r , th e acute di etary ri sk es timate is below R ED's l evel of concern at th e 99.91h pe r cen til e of ex po s ure. Th e acute dietary ex po s ure using D EE M was est im at ed for th e U .S. p opulation i s 13% o f th e aPAD and 27 % fo r a ll infants ( < 1 yrs o l d) , the most highly ex posed population subgroup
. The s t eady state aggregate d i etary (foo d and drinkin g wate r ) ex pos ure es timates us in g Ca l endex ar e above R ED' s leve l of co nce rn fo r the U.S. population and a ll po pulatio n subgro up s. Co mbined die ta ry ex pos ure from foo d and drinki n g water is 136% of P AD fo r the U.S
. p o pulation an d 358% of the PAD fo r c hildre n 1-2 yea rs, the most hi g hl y exposed popu l ation s ubgroup." AMVAC's comment: B ased on co nve rsatio ns w ith EPA , we hav e con ftnn ed that the information w ithin this t ext is inc o rrec t and refe r s to th at o f anot he r c hemical. HE D Re s ponse : T hi s e r ror wil l be co rrec t e d in the r ev i sed dietary expos ur e assess m e nt m e mora ndum
. 7. Within th e " IX. C hara cte ri za tio n o f In put s/Ou tputs" sect ion , I st pp ., EP A sta t es, " H ED has cond ucted unrefi ned acute and s teady s tate dietary ri s k assessments fo r co umaph os. OPs exh i b i

t a phen o m e no n known as stea d y state Ache in hibi t i o n and for co umapho s a s tead y state e ndpoint was se le cted
. A lth o u g h, there are rat da ta at a s horte r period ( i. e . 15 da ys) than 21 days, ex po s ure assess m e nt s of 2 1 da ys a nd lo nge r were conduc t ed for a ll routes of exposure ( i .e., ora l, dermal and inha l ati o n) fo r all s in g le c hem i ca l OP asse ss ment s using Calendex. Given thi s, th e 2 1-da y and lon ge r ex pos ur e assess m e nt is sc i e ntifica ll y suppo rtabl e a nd also provides co ns is t e nc y across the O Ps." AMVAC's comment: Ba sed o n co nversat io ns w ith EPA , we ha ve con finned th at the infonnation w i thin this text is inc o rre ct and r efe rs to that o f another c he mical. HED R es p o n se: Thi s e rro r wi ll be co rrec t e d in the rev is e d dieta ry exposu r e assess ment m e m o randum
. 8. Wit hin th e "X
. Co nc lu s i o n s" secti o n , I s t pp ., EP A s tates , " the se unre fin ed an a l ys e s d emo ns tra te that the requested u ses for dicrotophos wi ll not result in acute dietary risk es tim ate s that exceed HED 's l eve l of Page 3 o f 4concern fo r a ny of the regulated po pulati o n s ub gro up s . including th os e comprised of infant s and c hi l dr en." AMVAC's co mm e n t: T he acute dietary ri s k esti mat es at th e 9Sth percentile does not excee d s the aPAD for any of the s ubp o pulati o n g r o up s. Th i s would indi ca t e that acute aggrega t e exp os ure wo u l d not of conce rn. HEO Res p o n se: This error will be corrected in the revi sed dietary expo s ure assess m e nt m e morandum.

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