UN ITED STATES ENV IR ONMENT AI. P ROTECTION AGENCY WAS HINGTON D.C. , 20460

OFF ICE OF P REVENTION , P ESTICIDES AN D TOX IC SUBSTANCES
PC Code: 176603

### ~\**~\C>Y\** 

### -\±'LI-'d OL\'-\t) MEMORANDUM DATE: SUBJECT :
FROM:

TO : O ctober 4,2010 Section 3 Request for Zonas tat, a New Chemical Proposed for U se to Con trol Wild Horse s and Burros Nancy Andrews , Chief 

# f 

# JYYJ gi tJc j:M/ 

# o Edward Odenkirchen , Senior

# Ad**~( f-!VJ:.**  (jJ

# Ue O/f{ / O Su jatha Sankula, Lead Biolog ist 

# ."'"\ ?'7J 7 Brian Anderson, B iologist 

# t -.r. I 7**{j'** Environmental Risk B ranch llEFED (7 5 07P) John Hebert , Product Manager Insecticide Rodentici de Branch Regi stration Divi sion (750 5 P)


### 1 . Sum mary of Pro posed A ction: The Humane Society of the United Sta tes is applying for Section 3 re gistration for ZonaStat-H (porcine Zona pellucida) to control feral and wi ld horses and b urros. The active ingredient is porcine Zona pellucida (PZP) , which is an imrnunocontraceptive vaccine tha t is administered to target animals via intramuscular injection (either by dart o r by hand)
. The application rate is 1.0 cc of PZ P 

### + adjuvan t ( modified Freund 's complete adjuvant or m odified Freund's incomplete adjuvant). A second administration i s given 2 to 4 weeks after the initial priming dose then annually thereafter.



# .- .This memorandum discusses the data requirements and qualitatively characterizes potential risks to non-target organisms from the proposed use. 2
. Status of Submitted Data No studies have been submitted in support of this Section 3
. Waivers were submitted to fulfill required ecological effects and environmental fate guideline studies. Although the proposed use could qualify as outdoor uses, there are no exposure routes to non-target plants or animals that are likely to occur (see Section 3 of this document). Given the lack of potential exposures to non-target organisms , the proposed use pattern is more consistent with an indoor use from a data requirements perspective. For indoor uses, no studies are required. However , an acute oral study in birds , acute studies in aquatic animals, and hydrolysis studies are conditionally required. These studies are not considered to be necessary for the proposed uses for the following reasons: • Ac ute oral studies in birds: Oral exposure could occur via consumption of treated animals. However, the proposed active ingredient is a protein that is expected to be denatured after oral consumption. This is evidenced by the lack of efficacy via oral exposure (the active ingredient must be injected to target animals to be effective). Therefore, acute oral toxicity studies are not being required at this time
. • Acu te st udies i n a quatic an imals a nd hy dro lysis: Potential for contamination of water is limited
. The active ingredient is not expected to be excreted intact from treated animals
. Therefore, exposure to aquatic systems is limited to entry of wayward darts
. A dart contains 100 ug of active ingredient (MRID 47859805). Therefore , even if the contents of a dart were to enter a pond the size of EPA's standard ecological water body of 20 ,000,000 L , the resulting concentration would be 0.005 ngIL. Due to the limited possibility of exposure occurring to non -target aquatic or terrestrial animals, no data are being required at this time for the proposed use . 3.
. Potential Exposure and R isk to Non -Target Organisms Given that the proposed administration route is by injection (either dart or hand) to the target animal , potential exposure routes for non-target organisms resulting from labeled uses is somewhat limited. Potential exposure pathways to non -target organisms could include secondary exposure to carnivores, exposure to excreted material , and exposure from wayward darts (accidental exposure). All of these exposure pathways, however, are considered unlikely to result in potential risks to non -target organisms at levels of concern to the Agency as described below
. Dietary exposure to Zonastat is not expected to result in adverse effects at levels of concern to the Agency because it is a protein that is anticipated to be deactivated in the digestive tract, and absorption from the Gl tract is expected to be limited. Also , excretion data indicates that the short half -life in treated mammals suggests that the potential for secondary exposure is limited.

2Pote ntial exposure to aquatic environments is expected to be limited to accidental exposure s. Ho wever, as previ ously di scussed, even if a wayward dart were to enter a w ater body and all of the Zonastat within the dart were to enter a water body , the resulting concentration would be n eg ligible ( 5x lO

9 mgIL ). Bec ause the active ingredient is a protein , it w ould be expected to b e rapidly degraded i n natur al waters.


### 4 . 

### Threatened and 

### Endangered Species Concern 

### 4.1. Action Area For li sted species asse s sment purpo ses . the action area i s considered to be the area affected d irectl y or indire ctly by the Federal act ion and n ot merel y the immediate area in volved in the action. At the initial s creening

- level, the risk assessment considers b roadly described tax onomic group s and so conservatively assumes that listed species within tho se broad groups are co -located w ith the pe sticide treatment area . Thi s me ans th at t errestrial plant s and wildlife are a ssumed t o be located on or adjacent to the treated site and aquatic o rganisms are assu med t o be l ocated in a surface water body adjacent t o the tre ated site
. The a ssessment also ass umes th at li sted species are located w ithin an a s sumed area , which ha s the relatively h ighest p otential exp osure to the pe sticide, and th at exposures are likely t o de crease with distance from the tre atment area. If the ass umptions ass ociated with the s creening-level action area result in RQ s that are below the li sted specie s LOCs , a "no effect" determination conclusion is m ade with respect t o listed specie s in that tax a, and no further refinement of the act ion area i s ne cessary . Furthermore, RQ s below the li sted species LOCs f or a gi ven tax onomic group indicate no c oncern for indirect effect s upon li sted s pecies tha t depend upon the t axonomic gro up c overed by the RQ as a resource. However, i n situations where the screening assumption s le ad to RQ s in exces s o f the li sted specie s LOCs for a given taxonom ic group, a p otential for a " may aff ect" conclusion exi sts and may be a ssociated with direct effect s on li sted s pecies belong ing to th at tax onomic group or may extend to indirect effects upon l isted species that de pend upon that t ax onom ic group as a re source . In s uch cas es, additi onal inform ation on th e b iology o f l i s ted species, the l ocations of thes e s pecies, a nd the location s of us e s ites co uld be c onsidered t o determine the extent to wh ich s creening assumptions regarding an ac tion are a apply to a particular li sted organi sm. These s ubsequent refinement s teps could cons ider h ow thi s inf ormati on w ould impact the action are a f or a part icular listed o rganism and m ay p otentially i nclude area s of exposure that are downwind and downstream of the p esticide use site. Fo r th is ass essment , RQs were not c alculated. Howe ver, use of Zona stat could result in the fo llowing environmental e ffects: 1. Reducti on i n wi ld hor se slburros; 2 . Incre ased ris k of death and m orbidity re sulting f rom a llergic re sponses. Thes e poss ible environmental effect s cou ld affect listed spe cies by the f oll owing :



### 3• Reduct ion in wild h orse population s could con stitute an avenue for e ffects o n lis ted s pecies by redu cing pre y b ase o f li sted species ( negative effect ); • Re duction in w ild hor se p opulation s co uld re sult in habi tat re sponses th at may p ositively affect li sted specie s due to reduction s in overpopu lation; • Increa sed pre sence o f moribund anim als that may occur v ia alle rgic responses co uld re sult in increased c arrion availability ( i.e
. f ood f or cond ors , positive eff ect);
. 4 .2. Co-Location Analysis T o dete rmine whether the pro posed us es ar e geogr aphically as sociated w ith kn own locatio ns of listed s pecies, a s creening-level s earch of the LOC ATES ( version 2.10 .3) database is typ ically conducted. The d atabase c ompared county- level location data fo r listed s pecies w ith c ounty-level crop produ ction d ata (as ava ilable in the 2002 agricultural c ensus) to id entif y any c oarse overlaps o f li sted s pecies with the proposed labeled use s of Zo nastat. Li sted s pecies are those that are currently on the Fed eral li st of endangered and thre atened w ildlife and plants
. Howe ver, f or the current proposed reg istration for u se o f Zon astat on wil d hor ses and burro s, there are no geographical limitations included on the l abels, and g eographical limitations regarding whe re Zona stat may be used are uncert ain
. Th erefore, it i s a ssumed that Z onastat may be u sed in any c ounty in the United State s fo r the s creening le vel an alysis
. For this reas on, it is assumed that every federally listed specie s ma y b e affected by the proposed uses of Zon astat , and a LOCATES analysis was not conducted. The LO CATES databa se identifie s th ose U.S. counties that include non-cr op and turf areas an d that h ave f ederally-listed endangered or threatened species that may be dire ctly or indirectly affected
. The li st of affected s pecies derived from LOCATES wa s not includ ed in th is a ssessment because the u ses cover most of the United States and the direc t and indirect e ffects include s most species. With additi onal refinement by exploring more det ailed u se p atterns and species biol ogy ( e.g . , ge ographi c location, specific feeding habit s, t ime of ye ar likely to utilize crop fi elds), s ome s pecies li sted may be determ ined to be n ot likely to be affe cted.
4 .3. Taxonomic Gro ups Potentially at Risk A su mmary o f the risk conclu sions and dire ct and indirect effe cts determ inations is pre sented in Table 1
. Becau se th e prop osed u ses cann ot be ge ographi cally limited , all federally listed spe cies are ass umed t o be poten tially indire ctly affected. Table 1. P otential Listed Species R is ks Associated wit h Direct or In direct E ffects Due to t he Pro posed Use of Zo nastat! Listed Taxonomy Direc t E ffects Indirect E ffects Terrestrial and s emi-aquatic pl ants - No Yes mon ocots a nd d icots Terrestrial invertebrates N o Y es Bir ds (su rrogate f or terrestrial-phase No Yes amohibians a nd re otiles) M ammals No Yes



### 4

### Table 1. 

### Potential Listed Species Risks Associa ted wit h D irect or I ndirect Effec ts Due to the Proposed Use of 

### Zonastat' Listed Taxonomy Direct E ffects Indirect Effects Aquat ic vascular ol ants N o Ye s Aquatic n on-va scular plants No Ye s Freshwater fish (s urrogate for aquatic- N o Yes [ p has e a mphibians) Fre shwater Invertebrate s No Ye s Fre shwater Benthic I nvertebrates No Yes E stu arinelMarine F ish N o Ye s Estuar ine/Marin e Cru staceans No Ye s Est uarinelMarine M ollusks N o Ye s I. Effe ct o n lis ted s pecies ma y be negat ive o r beneficial


### 5. Conclusions The available data s uggest that potential exposures to non -target animals is not expected to re sult in any si gnificant risk concerns to terrestrial or aquatic organisms from the proposed use
. However, indirect effects (potentially ben eficial o r negative) to Listed species could not be precluded
.

5