# U.S. Environmental Protection Agency Office of Pesticide Programs
Environmental Fate and Ecological Risk Assessment for the Registration of Orthosulfamuron

N

O NH S O O

NH O

NH
N N O

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### Orthosulfa muron 1-(4,6-dimethoxypyrimidin-2-y l)-3-[2-(dimethylcarbamo yl)phenylsulfamoyl]urea CAS Registry Number 213464-77-8 PC Code 108209

Prepared by: Christopher Salice, Biologist Greg Orrick, Environm ental Sc ientis t U. S. Environm ental Protection Agency Reviewed by: Off i ce of Pestic ide Prog r am s Edward Fite, Senior Scientist Environm ental Fate and Effects Division R. David Jones, Se nior Agronom i st Environm ental Risk Branch IV Elizabeth Behl, Branch Chief 1200 Pennsylvania Ave., NW Mail Code 7507P Washington DC 20460

## 1 Executive Summary
1.1 Nature of Chemical Stressor Isagro is seeking registration for the use of the new che m ical herbicide orthosulfam uron (IR5878; 1-(4,6-dim e thoxypyrim idin-2-yl)-3-[2-(d im ethylcarbam oyl)phenylsulfam oyl]urea) and its end-use products IR5878 50 W G ® (51.5% a.i ., water dispersible granule) and IR5878 0.5 GR® (0.51% a.i. dry granule). Th is is a national registration reque st for control of a num ber of weed species associated with rice cultivation. Ground or aerial applications are proposed once per year with rates of 0.0550 lbs a.i./A to 0.0689 lbs a.i./A for the water dispersible granule form ulation and 0.0663 lbs a.i./A fo r the dry granule form ulation.
1.2 Potential Risks to N on-target Organisms The results of this screening-level assessm ent i ndicate a potential for direct adverse acute effects to non-target non-vascular plants , freshwater vascular plants, and terrestrial and sem i -aquatic plants ( Table 1.1 ). Although this screening-le vel analysis indicates a li m ited potential for direct adverse effects to anim al species asso ciated w ith the use of orthosulfam uron on rice, indirect effects m ay result as a consequence of potential direct effects on plants.
Table 1.1. Summar y of Dir ect and Indire ct Effects for Federally Listed Species .

Listed Species Taxonom i c Gr ou p o f C onc ern Direct E ffects RQ Indirect E ffect s Po tential Ass o ciated Taxa 1 Aq uat i c va scul ar pl ant s Acut e: gr o wth 14 8 No No n- vasc ul ar p l ant s No ne 0. 14 No Estuari n e/m arine nonvasc ul ar pl ant s Acut e: cel l den s i ty 1. 84 No Dico t terrestrial p l ants Acut e: p l ant g r o w t h 2

. 4 5 -1 28 No M o n o c o t t e rres tri al pl ant s Acut e: pl ant gr owt h 2. 04

- 2

. 45 No Freshw ater fish Non e Yes Aqu atic & Terrestrial Plan ts Saltwater fish Non e Yes Aqu atic Plan ts Freshw ater inverteb rates Non e Yes Aqu atic & Terrestrial Plan ts Estuari n e/Marine Inverte b rates No ne Yes Aq uatic Plants Mo llu sks Non e Yes Aqu atic Plants Mamm a l s Non e Yes Aqu atic & Terrestrial Plan ts Bird s Non e Yes Aqu atic & Terrestrial Plants Terrest rial inv e rteb rates Non e Yes Aqu atic & Terrestrial Plants 1 Associate dTaxa refe rs to th o se taxa fo r wh ich the r e ar e direct effects t h at may indirectly affect a listed s p ecies tax a
. 

### Overall, po tentia l r i sks a ppear to b e greatest f o r aquatic vascular plant sp ecies and terrestrial and sem i -aquatic dicotyledonous plants since these organism s appear to be very sensitive. Functionally, estim ated risks m ay translate to reduced survival, reproduction, or growth in affected species with the potential fo r subse quent effects at higher levels of biological organization. Im portantly, the toxicity data also indicate that there is a po tential f o r adverse effects on rice crops associated with the use of orthosulfam ur on. A Tier II Seedling Em ergence test indicated that rice dry wei ght was reduced by alm ost 20% at exposures of 0.044 lbs a.i./A, which is low e r than the proposed use rate of (up to) 0.0689 lbs a.i./A.

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### For federally listed endangered or threatened (her eaf ter “liste d”) spec ies, acute risk le vels of concern were exceeded f o r aquatic v a scular plants, sem i -aquatic m onocot and dicot p l ants, and terrestrial monocot and dicot p l ants. No listed species acute or chronic L O Cs were exceeded for any anim al species evalu ated in this assessm ent. Because aqu atic p l ant risk quotient s are above the non-endangered species level of concern, the Agency considers this to be indicative of a potential for adverse effects to those listed sp ecies that rely ei ther on a specific plant s p ecies (plantspec ie s obligat e) o r m u ltiple plant spec ies ( p lant dep en d ant) f o r so m e component of their life cycle. There is a potential to affect som e listed pl ant species and the species which depend upon listed or non-listed plant species. Indir ect effects in this case should be considered for both terrestrial and aquatic anim al species. The extent to wh ich the proposed uses of orth osulfam uron will direc tly ef f ect plant spec ies and indir ectly ef f ect anim al species will require f urthe r as sessm ent; specifically, clear delineation of actio n area, identi fication of listed sp ecies that co -occur in areas of orthosulfam uron use, species-s pecific life history inform ation, and an evaluation of critical habit.
1.3 Conclusions - Exposure Characteriz ation Orthosulf amuron has lo w volatility and exhibits acid-b ase be havior, be in g incre asing ly soluble in water as pH increases. It r eadily hydrolyzes in hours to days at low pH (<7), but slowly hydrolyzes (half-life of months) at high pH (>7)

. Moderate biodegradation and slow photolysis (half-lives of m onths) also occur in aquatic environm ents. Orthosulfam uron is m oderately mobile in soil and shows affinity to organi c carbon. The compound presents a ground water concern in alkaline, sandy soils with a Fre undlich soil-to-water partition coefficient (K f 

### ) as low as 2.0 (1/n = 1.02). Orthosulfamuron’s m a jor route of degradation in acidic to neutral rice pa ddy water is hydrolysis, with a half-life of hours to days. Aerobic biode gradation is the m a jor r oute of degradation in alkaline rice paddy water, with a half-life of weeks to m onths. Both routes of degradation are expected at sim ilar rates ( i.e. half-lives of weeks) in paddy water of neutral pH. Major degradates include hydrol ysis products N-(4,6-dim e thoxypyrim idin-2-yl)urea (DOP urea; S12), 2-dimethylcarbam oylphenyl sulfam ic acid (DBS acid; S1), and 2 am ino-N,Ndim ethylbenzam ide (DB am ine; S4) and dem e thylation product 1-(4-hydroxy-6­ m ethoxypyrim idin-2-yl)-3-[2-(dim ethylcarbam oyl )phenylsulfamoyl]urea (o-desm e thyl orthosulfam uron; S9). Both orthosulfam uron and its o-desm ethyl degradate hydrolyze to DBS acid, which, in turn, hydrolyses to D B am ine. However, all four degradates are m oderately persistent, as peak detections of these degr adates occurred at up to 100-186 days after application. The toxicity of orthosulfam ur on’s major degradates has not been determ ined. For this assessm ent, the o-desm ethyl degradate, which is the only degradate that re tains the par ent com pound’s sulfam oylurea structural group, is of risk concern and assum e d to have equal toxicity as the parent. Aquatic exposure estim ates are based on an assumption of no degradation

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### and, therefore, m ay be us ed to represent expos ure to the parent com pound alone or the parent com pound and any number of its degradates of potential concern, including its o-desm ethyl degradate. No m e thodologies are used to assess terrestr ial exposure to o-desm ethyl orthosulfam uron, as its contribution to risk is not e xpected to alter terrestrial risk conclusions that are based on the fate, transport, and toxicity of the parent compound alone. The screening Interim Rice Model was used to assess high-end exposure in paddy water and released tail water from the proposed orthosulfam uron use. T h e Interim Rice Model does not account for degradation and assum e s 100% application efficiency, which m eans that spray drift is not accounted for separately. The single aque ous exposure estim ate produced with the Interim Rice Model was used to repres ent bo th acute and chronic exposure for aquatic organism s. 1.4 Conclusions - Effects Characteriz ation Orthosulfamuron is practically non-toxic to birds, m ammals, and honeybees under acute exposure co nditions and only slig htly toxic to fi s h and freshwater aquatic invertebrates. Orthosulfamuron is highly toxic to aquatic vascular plants, non- vascular plants, and terrestrial plants following acute exposure. In terrestr ial plants, dicotyledonous plants appear more sensitive to orthosulfam uron com p ared to m onoc otyledonous plants.
1.5 Uncertainties and D ata Gaps No data are available to assess the p o tential ri sk s associated with the m a jor degrad ates of orthosulfam uron, including the degradate of risk concern, o-desm ethyl orthosulfam uron. Wh ile these data are not required, the pot ential toxicity of orthosulfamuron degradat es is a source of uncertainty f o r this assessm e nt. In addition, th ere is som e uncertainty associated with the addition of an adjuvant to increase ef ficacy of orthosulfam uron and the po tential effects of the adjuvant and the adjuvant/active m i xture. Studies on non-vascular plants indicate that the addition of an adjuvant results in toxicity endpoints considerab ly lower than with the water dispersible granule form ulation alone. This s uggests that that additi on of the adjuvant m ay increase th e potential for adverse effects to p l ants associated w ith th e use of orthosulfamuron on rice. However, overall risk conclusions would not be alter ed f

o r this sc re ening- level assessm ent. Exposure estim ate uncertainty is related to the degree to which Interim Ri ce Model assum p tions do not describe actual use sites of orthosulfam uron.

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## Table of Contents
1 Executive Summary .. .......................................................................................... 2 1.1 Nature of Chemical Stressor .. ............................................................................................ 2 1.2 Potential Risks to N on-target Organisms .. ....................................................................... 2 1.3 Conclusions - Exposure Characteriz ation .. ...................................................................... 3 1.4 Conclusions - Effects Characteriz ation .. ........................................................................... 4 1.5 Uncertainties and D ata Gaps .. ........................................................................................... 4 

## 2 Problem Form ulation .. ....................................................................................... 7 2.1 Stressor Source and Distributio n .. .................................................................................... 7 2.1.1 Overview of Pesticide Usage .. ....................................................................................... 7 2.1.2 Toxicity Profile .. ............................................................................................................ 7 

## 3 Analys is ... ........................................................................................................... 11 3.1 Methods ... ................................................................................................................. .......... 11 3.2 Use Characteriz ation ... .................................................................................................... . 14 3.3 Exposure Characteriz ation ... ........................................................................................... 16 3.3.1 Environmental Fate and Transport Characterization ... ............................................ 16 3.3.1.1 Transport and Mobility

... ................................................................................... 17 3.3.1.2 Degradation

... ...................................................................................................... 18 3.3.1.3 Field Studies

... ..................................................................................................... 19 3.3.1.4 Bioconcentration

... .............................................................................................. 20 3.3.2 Degradates ... ................................................................................................................ 20 3.3.4 Measures of Aquatic Exposure ... ................................................................................ 22 3.3.5Measures of Terrestrial Exposure ... ........................................................................... 23 3.3.5.1 Terrestria l Animal Species

... .............................................................................. 23 3.3.5.1.1 Terrestrial Animal Exposure Modeling
... .................................................... 24 3.3.5.2 Terrestria l Plan t Species

... ................................................................................. 26 3.3.5.2.1 Terrestrial an d Semi-Aqu atic Plan t Exposure Modeling
... ......................... 26 3.3.5.3 Residue Studies

... ................................................................................................ 27 3.4. Ecological Effects Characterization ... ............................................................................ 27 3.4.1. Aquatic Effects C h aracterization ... ........................................................................... 28 3.4.1.1 Aquatic Animal Species

... ................................................................................... 30 3.4.1.1.a. Aquatic Animals: Acute E ffects
... ............................................................... 30 3.4.1.1.b. Aquatic Animals: Chronic Effects
... ........................................................... 31 3.4.1.1.c. Aquatic Animals: Sublethal Effects
... ......................................................... 32 3.4.1.1.d. Aquatic Animals: Field Studies
... ................................................................ 33 3.4.1.1.e. Plants Inhabiting Aquatic Areas
... .............................................................. 33 3.4.2. Terrestrial Effects Characterization ... ....................................................................... 34 3.4.2.1. Terrestrial Animals

... ......................................................................................... 36 3.4.2.1.a. Terrestrial Animals: Acu te Effects
... ........................................................... 36 3.4.2.1.b. Terrestrial Animals: Chronic Effects
... ....................................................... 37 3.4.2.1.d. Terrestrial Animal s: Field Studies
... ........................................................... 37 3.4.2.2. Terrestrial Pla n ts

... ............................................................................................ 37 

## 4 Ris kCharac teri zation ... .................................................................................... 38 4.1 Risk Estimation – Integratio n of Exposure and Effects Data ... .................................... 38

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### 4.1.1 Non-target Aquatic Organisms ... ................................................................................ 38 4.1.1.1 Freshw ater Fish and Invertebrates

... ................................................................ 38 4.1.1.2 Estuarine/Marine Fish and Invertebrates

... ..................................................... 39 4.1.1.3 Aquatic Plan ts

... .................................................................................................. 39 4.1.2 Non-target Terrestrial Organisms ... ........................................................................... 40 4.1.2.1 Birds

... .................................................................................................................. 40 4.1.2.2 Mammals

... .......................................................................................................... 41 4.1.2.3 Terrestria l Plan ts

... ............................................................................................. 42 4.2 Risk Description ... ........................................................................................................ ..... 43 4.2.1 Risk to Aquatic Organisms ... ...................................................................................... 43 4.2.1.1 Freshw ater Fish

... ................................................................................................ 43 4.2.1.2 Freshw ater Invertebrates

... ................................................................................ 43 4.2.1.3 Saltw ater Fish

... ................................................................................................... 44 4.2.1.4 Saltw ater Invertebrates

... ................................................................................... 44 4.2.1.5 Aquatic Plan ts

... .................................................................................................. 44 4.2.2 Risks to Terrestrial Organisms ... ................................................................................ 45 4.2.2.1 Birds

... .................................................................................................................. 45 4.2.2.2 Mammals

... .......................................................................................................... 45 4.2.2.3 Potentia l Risk to Birds and Mammals: BCF Analysis

... ............................. 45 4.2.2.4 Plants

... ................................................................................................................. 46 4.2.2.5 Non-Target Terres trial Invertebrates

... ............................................................ 47 4.2.3 Federally Threatened and Endange red (L isted) Species of Concern ... .................... 48 4.2.3.1 Action Area

... ....................................................................................................... 48 4.2.3.2 Taxonomic Groups Potentially at Risk

... .......................................................... 49 4.2.3.2.1 Listed Species Direct Effects
... ...................................................................... 50 4.2.3.2.2 Probit Dose-R esponse Analysis
... ................................................................. 51 4.2.3.2.3 Indirect Effects
... ........................................................................................... 52 4.2.3.2.4 Listed Species Occurrence Associ ated with Orthosulfamuron Uses
... ....... 53 4.3 Description of Assumptions, Limitations, and Data Gaps ... ......................................... 54 4.3.1 Assumptions and Limitations Re lated to E xposure for All Taxa ... ........................... 54 4.3.2 Assumptions and Limitations of Aquatic Exposure Estima tes ... .............................. 55 4.3.3 Assumptions and Limitations of Terres t rial Exposure Estima tes ... .......................... 55 4.3.3.1 Location of plan t species

... ................................................................................. 55 4.3.3.2 Routes of exposu re
... ........................................................................................... 55 4.3.3.3 Incidental Pesticide Rele ases Associated w i th Use

... ........................................ 55 4.3.4 Effects Assessmen t Assu mptions and Limitation ... ................................................... 56 4.3.4.1 Age Class and Sensitivity of Effects Thresholds

... ........................................... 56 4.3.4.2 Lack of Effects Data for Amphibians and Reptiles

... ...................................... 57 4.3.4.3 Use of the Most Sensitive S p ecies Tested

... ....................................................... 57 4.3.4.4 Data Gaps

... ......................................................................................................... 58 

## 5 Literature Cited ... ............................................................................................. 59 Submitted Studies ... ........................................................................................................... ..... 60

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## 2 Problem Formulation The Federal Insecticide, Fungi cide and Rodenticide Act (FIF RA) requires that registered pesticide uses do not pose unreasonable adverse effects to the environm ent, and the E ndangered Species Act requires that regulator y actions should not adversely a ffect Federally listed species or the i r hab i tats. The purpose of this assessm ent is to prov ide insight into the potentia l ef f ects to the environm ent associated with th e use of th e herbicide orthosulfam uron, as part of the supporting inform ation to determ ine the eligibilit y of orthosulfam uron for registration. This screening-level assessm ent follows m e thods detailed in the Overview Docum e nt (USEPA, 2004). Briefly, the m e thod involves com p aring es tim ates of exposure (m easures of exposure) with labo ratory-der ived toxic ity es tim ates (m easur es of effect). If m easures of effect exceed specified levels of concern (LOCs) for a give n m easure of exposure, deleterious effects on nontarget organism s may potentially occur and a m o re refined assessm ent m ay be warranted to better define potential risks. Although screening-level m e thods ar e sim ilar for all chem icals, the problem formulation section helps to focus atte ntion on unique or im portant characteristics of a given chem ical, thereby providing a se nse of the potential environm enta l risks of that chem ical.
2.1 Stressor Source and Distributio n 2.1.1 Overview of Pesticide Usage
Orthosulfamuron (1-(4,6-dim ethoxypyrim idin-2-yl )-3-[2-(dim ethylcarbam oyl)phenylsulfam oyl ]­ urea; CAS#: 213464-77-8; PC code: 108209) is a sy stem ic post-em ergence herbicide belonging to the su lfamoylurea class of herbicides. Su lfamoylurea herbicides ac t through inhibition of branch-chain am ino acid biosynthesis in plants. Orthosulfamuron’s specific m ode of action is through th e inhibition of the plant enzym e , acet olactate synthase, also kno wn as aceto hydroxy acid synthase (ALS/AHAS). Inhibition of ALS/AHAS blocks the branched-chain am ino acid biosynthesis of valine, leucine, and isoleucine, which are involved in the plant growth process. Orthosulfamuron is formulated as both a water dispersibl e granule (IR5878 50 W G ) and a granule (IR5878 0.5 GR). The m anufacturer r ecommends that for m axi mum effectiveness in protection against com p etitive weed species, formulations of orthosulfam uron be applied to young, em er ging rice plants at the 1 to 2 leaf (IR5878 0.5 GR) or 2 to 4 leaf (IR5878 50 W G ) growth stage. The dispersible granule form ul ation of orthosulfam uron should be applied via ground or aerial foliar spray treatm e nt to a partially or fully dr ained rice paddy and the granular form ulation should be applied via direct dr y application by ground or air equipm ent to a perm anently flooded rice paddy. Proposed labels for orthosulfam uron (EPA Reg. No.s pending) specify use on rice only, with application rates of 0.0663 lbs a.i. /A for the granule and ranging from 0.0550 to 0.0689 lbs a.i./A for the water dispersible granule.
2.1.2 Toxicity Profile In addition to the environm ental fate characteristics of orthos ulfam uron, the toxicity of the chem ical plays an im portant role in evaluati ng po tential env i r o nm ental r i s k s. A com p lete toxicity dataset was provided fo r the parent, orthosulfam uron. The suite of toxicity studies

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### provides the m easures of effect, which are toxi city endpoints. These are intended to provide insight into the potential effect s on assessm ent endpoints, defined as “explicit expressions of the actual environm ental value to be protected” (US E PA, 1998). For m ost pesticides, including orthosulfam uron, the assessm ent endpoints relate to the sustainability of populations or the m aintenance of comm uni ty stru ctur e for plants an d anim als. While asses sing risks at the population and community level are endpoints useful for risk m anage m e nt , the lack of adequate data lim its the ability to address these endpoint s with m eaningful scie ntific rigor (ECOFRAM, 1999). The toxicological profile for orthosulf am uron indicates that fo r m o st tested anim al species, orthosulfam uron is not highly toxic with designations rangi ng from practically non-toxic (m ammalian and avian species) to m oderately to xic (som e aquatic species). Orthosulf am uron, however, is extrem ely to xic to terrestrial and aqu atic p l ant sp ecies

. The toxicity of orthosulfam uron’s m a jor degradates, DBS acid (m ax. 62% of applied at 7 days), DB am ine (m ax. 13% of applied at 176 days), DOP urea (m ax. 111% of applied at 7 days), and o-desm ethyl orthosulfam uron (m ax. 19% of applied at 100 days ) have not been determ ined. The o-desm ethyl degradate is the only identified de g r adate th at cont ains the su lfam oylurea structural gro up that the parent com pound contains. Therefore, the o- desm ethyl degradate is assum e d to have equal toxicity as the parent compound and is of risk concern. Table 2.1 provides a list of th e taxonom ic groups, m easures of ef fect and most sensitive test species evaluated for the toxico logical eff ects of orthosulfam ur on; these provide the toxicological basis for risk estim ations and conclusions in this assessm ent. Given the sensitivity of plant and algae species, it is likelythat the m o st delete riou s effects of orthosulfam uron m ay relate to the survival, growth, and reproduction of plants and algae with potential i ndirect effects to anim al species d epen d ent on im pacted p l ant s p ecies.
Table 2. 1. TaxonomicGr ou ps and Most S e nsitiv e Speci es Evaluated for Ec ological Effects of Orth osul fam u ron. Assessm ent Endpoint for Eac h Taxo no m i c G r o u p Represe ntative Test Species Measure of E f fect Use din Assessm ent In di vi dual s urv i v al , g r owt han d r e pr odu ctio n of b ir ds a Bo bwh ite qu ail ( Co linu s virg i n ian u s ) Mallarddu ck ( An as plat yr

hyn c ho s ) Acute LD 50 /LC 50 Chro n ic NO AEC In di vi dual s urv i v al , g r owt han d r e pr odu ctio n of m ammals No rwayrat (Ra ttu s no rveg icu s ) Acute LD 50 Chro n i c NO AEC/N O A EL Terrest rial Inse ct survival Honeyb ee (Apis m e llifera) Acute Oral LD 50 In di vi dual s urv i v al o f f

r es hwat er fi s hb Rainbo w trout ( O n c hor hy nch u s myki ss ) Fathead m i nnow (Pi me ph al espr omelas ) Acute LC 50 Chro n ic NO AEC Fres hwate r invertebrate survi v al, growth and re pr o duct i on Water flea (D a ph ni a m a gn a ) Crayfish( Pr oc am brus clarki a ) Acute LC 50 Chro n ic NO AEC In di vi dual s urv i v al of sal tw at e r fi s hb Shee ps head m i nnow ( Cyp r i n idon variegatus ) Acute LC 50 Saltwater inv e rteb rate surv iv al, growth and re pr o duct i on Mysid shrim p ( Americamysis ba h i a ) Eastern oyster ( Crass o stre a vi rginic a ) Acute LC 50 /EC 50 Surv i v al and gr ow th of terr estrial p l ants Cu cum b er ( Cucumus sativa ) Acute EC 50 Survi v al and growth of a quati c plants and algae Algae ( Scene desmus s u bspic a tus ) Duc k weed (Le mn a gi b b a ) Acute LC 50

a Bird s are u s ed as surrog ates fo r rep tiles an dterrestrial-p h a se am p h i b i an s (USEPA, 200 4).



### 8b Fr eshw ater f ishar e u s ed as surr og ates f o r

aqu atic-ph a se am p h ib ian s (U SEPA , 2004 )

. 

### For pesticides in general, the ecosystem s at gr eatest risk are those in clos e proxim ity to the proposed use areas. These would include ag ricultural fields (surrounding non-agricultural terrestrial habitats) and water bodies directly ad j acent to treated fields th at m ay receive chem ical residues via drift, runoff, and/or ground water discharge. The proposed use of orthosulfam uron on rice, how ever, is lim ited to application to rice paddies, which under go periodic flooding and draining. Hence, for orthosulfam uron, the predom in ant ecosystem s at risk are likely to be those aquatic and terrestrial habitats in close proxim ity to rice cultivation areas that receive rice paddy water (called tail water), ground water discharge, or spray drift from applications. W ithin these water bodies, the water column, sedim e nts, and pore water are all com p artm ents of concern. Organism s of concern include birds, m ammals, reptiles, fish, and terrestrial and aquatic invertebrates, plants, and am phibians. The a ssessm e nt endpoints are focused on the survival, growth, and reproduction of these organism s, whi c h are intended to relate to population sustainability and community structure within ecosystem s and hence relate back to ecosystem s at risk. If risks are expected for given species/taxa based on the screening- level assessm e nt, then risks m ay tr anslat e to h i gher lev els o f biologica l organiz ation , such as po pulations, co mmunities, or ecosystem s. The following risk hypothesis provide s a sense of the focus and intent of this risk assessm ent. The risk hyp o thesis is th at th e use of orthosulfamuron in acco rdance with the labe l res u lts in adverse effects on survival, grow th and/or reproduction of non- target terrestrial and/or aquatic animals; and that the use of orthosulfamuron in accordance with the lab el resu lts in adverse effects on survival and/or growth of te rrestrial, semi-aquatic, and aquatic plants. This screening assessm ent is designed to test this hypothesis. Failure to dism iss the risk hypothesis m ay indicate that there are risks of concern, or m ay be the result of the conservative assum ptions inherent in a screening level asse ssm e nt. Further refined assessm ent would be necessary to confirm that risk s are in deed present if the risk hypothesis is accepted. The conceptual m odel ( Figure 2.1 ) depicts the potential pathways for ecologica l risk associated with the proposed use of orthosulfam uron on rice. This m odel is fairly generic and assum e s that as an herbicide, orthosulfam uron can affect te rrestrial and aquatic organism s i f environm ental concentrations are sufficiently elevated as a resu lt of proposed label uses. However, the m odel differs from most conceptual m odels in that the application of pesticides to rice is unlike m ost other pesticide applications to agricultural field s
. Rice cultiv ation relies on the use of paddies that undergo a series of flooding and releasi ng for optim al growth and yield. Given the cultivation practices associated w ith rice, pesticides are frequently applied directly to rice paddy water. The release of rice paddy tail water m ay be an im portant source of environm ental exposures.

9Bir d s , Mamma ls , Terrest rial Wetlan d/ 

### Rece p tors Rep tiles, Terrestrial Upl and Rip arian Aqu atic Aqu atic Phase Am phi bi ans Plants Plants Plants Inverte b rates, 

### Stressor Ort hos ul fam ur o nAp pl i e d as a Gr o und/ Aeri al Sp rayo r Dr yGranul es t o R i ce Pad d i e s


### Source/ Transport Pathw a y s Direct Application to Pad dy Water Leaching (In f iltration

### / Perco l atio n


### Source/ Exposure Media Terrest rial Fo o d Item s (foliage, fru it, in sects, seeds ) Upl and Fo liag e /So il Rip arian/ Wetlan d Fo liag e /So il Receiving Water B ody/

Sedi m e nt G r o und W ater



### Exposure Route In gest i o n Direct Contact/ R oot Up t ake Direct Contact/ R oot Up t ake Gill/ In tegum e n t

Uptake Terrest rial Ve rt ebrates: Up tak e / Ad sorp tion Spray Drift Granules



### Attribute Changes In di vi dual An i m al s R e duce ds urvi v al o r r e pr odu ctio n Verte b rates

In di vi dual Pl ant s R e duce ds urvi v al , gr owt h , o r rep r od uct i o n In di vi dual Verte b rates an d Inverte b rates R e duce ds urvi v al or

re pr o duct i o n Plant Po pu lation R e duce d p opu latio n gr owt h



### Figure 2.1. Conceptual model of the transpor t and effects of orthosulfamuron in the environmen t. * D o ttedlines i n d i cate t h at alth oug h th is expo sure ro ut e was con s id ered , it was no t thou gh t to con tribute sign ifican tly to th e fate an d tran sp ort o f orth o s u l fam uro n. 

### Ground water concentrations estim ated with the screening m o del SCI-GROW (EEC=0.6 ppb) are ins i gnif i cant com p ared to surf ace water conc e ntrations e stim ated with the scr eenin g Inter i m Rice Model (EEC=38.6 ppb). This m eans that orthosulfam uron residues in discharged ground water leachate are not expected to co ntribute sign ificantly to surface water exposure. Therefore, the potential pathways of aquatic exp o sure cons id ered in risk estim ation f o r this risk a ssessm ent, as indicated in the con c eptual m odel, include surface water runoff and spray drift and do not include ground water discharge. Note that the spray application of orthosulfam uron is repres ented in the con ceptual m odel because it lik ely rep r esents a broad e r spectrum of potential exposures com pared to the dry granule application. The conceptual m odel provides an overview of the expected exposure routes for organism s in and around the orthosulfam uron use area. For terr estrial organism s, the major route of exposure considered is the dietary route; consum ption of food item s such as plant leaves or insects that have orthosulfam uron r e sidues as a result of spraying or from di rect consum ption of granules. Specifically for orthosulf am uron, consum ption of residues on food item s may be lim ited to the

10

## 3 dispers i ble g r anule form ulation and to areas outside the rice p addy. In ad dition, there is the potential for dietary exposure to terrestrial o r gan i sm s via th e consum ption of contam i n ated aquatic species in which orthosul fam uron m ay have bioaccum u lated. Fo r aquatic anim al species, the m a jor routes of exposure are considered to be via the respiratory surface (gills) or the integum ent. Direct contact and/ or root uptake is the m a jor rout e of exposure for terrestrial and wetland (riparian) plants, while aquatic plants m ay be exposed via direct uptake and adsorption. Because orthosulfam uron has not been previous ly regis t ered, no m onitoring data are availab l e. Estim ated exposure concentrations for all organism s are obtained through the use of several Agency exposure m odels. Aquatic exposure estim ates are based on an assum ption of no degradation and, therefore, m ay be us ed to re present exposure to the parent com pound alone or the parent com pound and any num ber of its degrad ates, including its o-desm ethyl degradate of risk concern. No m e thodologies are used to assess terrestrial exposure to o-desm ethyl orthosulfam uron, as its contribution to risk is not e xpected to alter terrestrial risk conclusions that are based on the fate, transport, and toxicity of the parent compound alone. To generate screening-le vel estim ates of risk, the m easures of exposure, (derived from m odeled laboratory f ate data) are com p ared to the m easures of effect (obtained fr om laboratory toxicity studies). Functionally, the com parison involves dividing the m easures of exposure (E ECs) by the m easures of effect for a given taxa. The re sulting unitless value is th e risk quotient (RQ). The RQ is then com pared to the Ag ency’s levels of concern (LOC) for direct effects. The LOCs are the policy tool for analyzing potential risk to non- target organism s; if the RQ exceeds the LOC for a given taxa and exposure duration, there is a potential for adverse effects to non-target organism s. A m ore detailed description of the me thods used to assess risks is provided in the next section (Section 3; Analysis). All environm ental f ate and ef f ects data r equir e d to be subm itted to the Agency have been subm itted and are adequ ate, with the exception o f those regar d ing anae ro bic aquatic m etabolism

. The subm itted data indic ate th at orth osulf am uron is m o st toxic to aquatic plants, hyd r o lyzes quickly in a cidic enviro nm ents, is moderatelype rsis tent in alkalin e environm ents, and is moderately to slightly mobile in soil. 

## Analysis
3.1 Methods The prim ary m e thod used to assess risk in this screening-level assessm ent is the determ inistic risk quotient m ethod as o utlin ed in th e Overview of the Ecolo g ical Risk Assessm ent Process in the Office of Pesticide Program s (USEPA, 2004). The RQ is a unitless value that is the result of com p aring, by division, m easures of exposure to m easures of effect. Commonly used m e asures of exposure are the estimated exposure concentrations (EECs) and commonl y used m easures of effect includ e toxicity values such as the LD 50 

### or the NOAE C. The assessm e nt endpoints and the corresponding m easures of exposure and m easur es of effect used to address risks to the assessm ent endpoints are outlined in Table 3.1

.

11

### Table 3.1. A ssessment E ndpoints. Assessment Endpoints Measures of Effect Measures of Exposure Terrestrial Assessment Endpoints Avian Survival Avian acute oral LD 50 

### , dietaryLC 50 

### Maxi m um , peak residue concentration of foo ditem s Avian reprod uction and/ or survival NOAEC fro m avian chronic reproduction study Maxi m um , peak residue concentration of foo ditem s Mammalian Survival Mammalian acute oral LD 50 

### Maxi m um , peak residue concentration of foo ditem s Mammalian reproductionand/or survival NOAEC fro m 2-gener ation reproduction study Maxi m um , peak residue concentration of foo ditem s Beneficial Ins ect Survival Honeybee ac ute contact LD 50 

### Maxim um ap plication rate Terrestrial pl ant survival and growth Tier II plant t oxicitydata; EC 25 

### , NOAEC/E C 05 

### Peak esti m ate from Interi m Rice Model and spraydrift estimates to non-target areas Aquatic Assessment End p oints Freshwater fi sh survival Freshwater fi sh acute LD 50 

### Peak esti m ate from ric e m o del Freshwater fish reproducti on and/or survi v al Chronic fish studyNOAEC Peak esti m ate from ric e m o del
Freshwater in vertebrate surv ival Freshwater in vertebrate ac ute EC 50 

### Peak esti m ate from ric e m o del Freshwater in vertebrate reproduction and/or survi v al Freshwater in vertebrate life cy cle NOAEC Peak esti m ate from ric e m o del
Estuarine/m arine fish surviv al Freshwater fi sh acute LD 50 

### Peak esti m ate from ric e m o del Estuarine/m arine fish reproduction and/or survi v al Chronic fish studyNOAEC Peak esti m ate from ric e m o del
Estuarine/m arine invertebrate survival Freshwater in vertebrate ac ute EC 50 

### Peak esti m ate from ric e m o del
Estuarine/m arine invertebrate reproduction and/or survi v al Freshwater in vertebrate life cy cle NOAEC Peak esti m ate from ric e m o del Aquatic vascular and no nvascular plant survival and growth Tier I, Tier II plant toxicity data; EC 25 

### , NOAEC/EC 05 

### Peak esti m ate from ric e m o del



### The RQ that results from a given comparison of exposure and effect is com pared to a specified level of con cern; if the RQ ex ceeds the LOC, then advers e effect s are co nsidered po s sible and a more refined assessm ent m ay be warranted to bette r define potential risks. Although not a true estim ate of risk since there is no estim ated proba bility or m a gnitude of an adverse effect, in general, the higher the RQ, th e m o re concern for the like lihood of adverse effects ( Table 3.2 ). Levels of concern are the policy t ool for interpreting RQs in the context of risks to receptors as a result of direct pestic ide effects. The m a gnitude of the LO C is set by the risk presum ption for each endpoint ( Tables 3.3-3.5 ). Im portantly, there are im plic it com ponents of the LOC, which

12

### include duration, frequency and spatial considerat ions. Duration is determined prim arily by the assessm ent endpoint evaluated and falls typically within the context of acute (shorter) and chronic (longer) continu ous exposures. The exact duration is taxa-specific and relates to the general characteristics of that taxa’s life hist o ry. For exam ple, m any freshwater inv e rtebrates have a relatively short life-span; hence chronic exposure estim ates would be shorter than longerlived organism s such as fish. The proposed use of orthosulfam uron specifies only one application f o r use on rice; both terrestrial and aquatic exposure estim ates are based on peak values. The spatial extentof the screening-le vel assessm ent is defined by the use area, and the areas downstream and those areas potentially aff ected by spray drift. For aquatic assessm ents, exposure will vary with proxim ity to the tr eated areas. Because the proposed use of orthosulfam uron is for rice, higher exposures are expected for organism s near paddies where tail water release would contain the hi ghest levels of orthosulfam uron. Table 3.2. Risk presu m ptions fo r terrestri al animals (birds and w ild mammals). Risk Presumption RQ LOC Acute EEC * 

### /LC 50 

### or LD 50 

### /f t 2* * 

### or LD 50 

### /day ** * 

### 0.5 Acute Restricted Use EEC/LC 50 

### or LD 50 

### /f t 2 

### or LD 50 

### /day (or LD 50 

### < 50m g /kg) 0.2 Acute Listed Species EEC/LC 50 

### or LD 50 

### /f t 2 

### or LD 50 

### /day 0.1 Chronic EEC/NOAEC 1.0 * Estim ated Exposure Concentration (ppm ) on avian/m ammalian food item s ** m g/ft 2 

### / LD 50 

### (body-weight scaled) *** m g of t oxicant consum ed/day / LD 50 

### (body-weight scaled)

Table 3.3. Risk presu m ptions for aquatic animals. Risk Presumption RQ LOC Acute EEC * 

### /LC 50 

### or EC 50 

### 0.5 Acute Restricted Use EEC * 

### /LC 50 

### or EC 50 

### 0.1 Acute Listed Species EEC * 

### /LC 50 

### or EC 50 

### 0.05 Chronic EEC/NOAEC 1.0 * EEC = (ppm or ppb) in water

Table 3.4. Risk presu m ptions fo r t errestrial and semi-a quatic plan ts. Risk Presumption RQ LOC Acute EEC * 

### /LC 50 

### or EC 50 

### 1.0 Acute Listed Species EEC/EC 05 

### or NOAEC 1.0 * EEC = lbs a.i./A

Table 3.5. Risk presu m ptions for aquatic plants. Risk Presumption RQ LOC Acute High Risk EEC * 

### /LC 50 

### or EC 50 

### 1.0 Acute Listed Species EEC/EC 05 

### or NOAEC 1.0 * EEC = (ppm or ppb) in water

13

### The exposure estim ates in this screening-level assessm ent are derived using the m axi mum label rate. M easur es of effects are bas e d on the lowes t available toxicity endpoint for a given taxa and exposure duration.
3.2 Use Characteriz ation Orthosulfamuron is proposed for use in rice pa ddies as post-em ergent weed control and is form ulated as a dry granule and as a water dispersible granul e. The label for the water dispersible granule form ulation (IR5878 50 W G ; 51.5% a.i.) directs users to m i x with water at the approp riate rates and apply as spray via ground or air equipm ent to fully or partially drained wet-seeded or dry-seeded rice. The label for the granular formulation (IR5878 0.5 GR; 0.51% a.i.) directs users to apply via direct dry application by ground or air equipm ent to perm anently flooded rice. For both form ulations of orthosulfamuron, the proposed label recomm ends application when weeds are young, em erging and actively growing. Maxim um seasonal applications for the proposed use on rice are si m ilar for both f o rm ulations at approximately 0.07 lbs a.i. /A an d lim ited to 1 applic atio n per year
. Use rates and m anage m e nt practices by crop accord ing to proposed labels are presented in Table 3.6 , based on the Petition for Tolerances subm itted by Isagro S.p. A. (June 20, 2005).

Table 3.6. P r oposed Uses of Orthos ul famuron; Maximum Ap plication Rat es. Crop/Use Form ulated Product Application Rate fl. oz./A M ax i mum Application Rate (lbs a.i./A) M ax i mum Nu m b er of Applications M ax i mum Y e ar l y Application (lbs a.i./A) IR5878 50 W G(Dispersible Granule) Rice 2.14 0.06 9 1 0.06 9 IR5878 0.5 G R (Granule) Rice N/A (dry granule form ulation) 0.06 6 1 0.06 6


### For purposes of this screening-level assessm ent, estim ates of risk are based on m aximum proposed label rates for the water dispersible granule form ul ation (IR 5878 50 W G ) since it is slightly gr eater than the applic ation rate for the dry granule ( Table 3.6 ). In the United States, rice is grown prim arily in two regions. The Southern region consists of the Gulf Coast of Texas and Southwest Louisiana and the Mississippi River V a lley in parts of Louisiana, Mississippi, Arkansas, and Missouri. The rem a inder of dom e stic rice production is located in th e Sacram ento Valley and San Joaqui n Valley of California. Other states known to potentially produce sm all quantities of rice incl ude Illinois, Florida, Oklahom a , and Tennessee (National Agricultural S t at istics Service, 2002). Successful rice cu ltiv ation relies on three g e nera l rice paddy irrigation pr actices in accordance with the life cycle of the crop, dry seeding, wet seeding, and water seeding. Dry seeding is the most common practice in the Southern region of the United S t ates, wherein seeds are grown in

14

### dry beds several weeks before establishing a pe rm anent flood in the paddy. Sm all amounts of water are used to assist seed germ ination, but the field is left dry until the rice has sprouted and begun to grow. W e t seeding also occurs in the S outhern region of the United States through "pin point" flood culture, wherein pre-sp routed rice is aerially applie d to flooded fields that are drained a few days later and flooded again several days later. In Ca lifornia, the m a jority of rice production is water seeded with a continuous fl ood, wherein a steady flowof aerobic water is m a intained through the paddy. Although actual water depth within a paddy m ay be shallow (1-4 inches ), given the size of individual paddies and the co-l ocation of m any paddies, rice cultivation m ay involve large quantities of water. Im portantly, for areas that m ay be dom inated by rice cultivation, the sim ultaneous release or drainage of paddy tail water could contri bute significant quantities of water to nearby water bodies.

15

### Figure 3.1. Location of Rice Harvested in the United States in 2002 (USDA, 2006). 3.3 Exposure Characteriz ation
3.3.1 Environmental Fate and Transport Characterization Orthosulfamuron exhibits acid-base behavior, as its water so lubility and o c tanol-to

- water partition i ng depend on e nvironm ental pH. It is p r edicted to have f i ve disso ciation cons tants (pKa of -1.4, 0.7, 3.5, 9.6, and 11.5) and to be fully neutral at ca. pH 2 to 2.5. The compound’s persistence depends on environm ental pH as well, as the compound readily undergoes acid catalyzed hydrolysis (half-life of hours to days). As alkaline conditi ons increase, the com pound is increasingly hydrolytically stable in water (half-life of 7 m o nths). Biodegradation in aerobic and anae robic aquatic conditions occurs on a scale of m onths. Due to its low vapo r pressure an d high water solubility, v o latilization from water and soil surfaces is no t expected to be an im portant ro ute of environm ental dissipation. Orthosulfam uron is moderately to slightly m obile in soils, presenting a ground water concern in alkaline sandy soils with low organic carb on content. Leaching an d aquatic fiel d diss ipatio n data ind i cate that som e of the transform ation products of the com p ound are m o re susceptible to leaching than the parent.

16

### Orthosulfamuron’s m a jor route of degradation in acidic to neutral rice pa ddy water is hydrolysis, with a half-life of hours to days. Aerobic biode gradation is the m a jor r oute of degradation in alkaline rice paddy water, with a half-life of weeks to m onths. Both routes of degradation are expected at sim ilar rates ( i.e. half-lives of weeks) in paddy water of neutral pH. The general physical/chem i cal properties of orth osulfam uron are summ arized in Table 3.7

. Table 3.7. G e neral che m i c al propertie s and envi ronmental fate parameters of orthosulfamuron. Chemi c al/Fate Paramete r Value Source Molecular m a ss 424. 44 MRID 46219 074 Vapor pressure (20 ° C) 8.4 x10 -7 

### t o rr MRID 46219 010 Water solubility (20 ° C) 26.2 m g /L (pH 4) 629 m g /L (pH 7) 38,9 00 m g /L (pH 8.5) MRID 46219 009

Octanol-to-water partition coefficient (K OW 

### ) 104 (pH 4) 20. 5 (pH 7) <2.0 (pH 10) MRID 46219 012

Freundlich soil-to-water partition coefficients ( K f 

### ) for adsorption (soil type) 2.0 (1/ n= 1.02) (silt loam ) 2.4 (1/n = 0.97) (sandyloam ) 3.6 (1/ n= 1.1 5 ) (sand) 3.8 (1/n = 0.75) (sandyloam ) 5.5 (1/ n= 0.92) (silt loam ) 5.7 (1/n = 0.96) (clayloam) 6.6 (1/ n= 0.86) (silt loam ) 6.9 (1/ n= 0.9 9 ) (loam ) 8.2 (1/n = 1.06) (sandyloam ) 20 (1/n = 0.98) (clayloam) MRID 46219 074 MRID 46578 971

Organic carb on norm ali z ed partition coefficients ( K OC 

### ) 1 

### 217, 228 , 24 9 , 283 , 32 6, 3 5 0, 38 1, 5 47, 653, 233 0 L/kg OC 

### MRID 46219 074 MRID 46578 971 Hy dr ol y s is half-life (25 ° C) 0. 442 d (p H 5) 24. 4 d (p H 7) 228 d (p H 9) MRID 46219 015 MRID 46578 970 Aqueous pho tol y sis half-life 180 d (laborat or yvalue) MRID 46588 509 Aerobic aquatic m e tabolism half-lives 30.3, 59. 2, 6 5

. 4, 7 0 .5 d MRID 46219 017 Anaerobic aqueous m e tabolism half- lives 88, 1 42, 161 , 217 d MRID 46578 967 1 K OC valu es w e re cal cul at e d base d on Kf va l u es f o r a d so r p t i on ( e.g. , K OC = K f (ad s o r pt i o n) ÷ % or gani c car bo n)

. 

### The environm ental fate and transport properties of orthosulfam uron are characterized below. Our understanding of these properties is lim ited by the data set available. Many chemical properties and environm ental fate param e ters of orthosulfam uron listed in Table 3.7 are based on single, supplem e ntal studies, summ aries of which are in Appendix B

. 3.3.1.1 Transport and Mobility Orthosulfamuron exhibits acid-base behavior, as indicated by its r anges o f water solu bility and octanol-to-water partitioning acr oss environm ental pH values. The com p ound is predicted to

17

### have five dissociation constants (pK a

### of -1.4, 0.7, 3.5, 9.6, and 11.5) and to be fully neutral at ca. pH 2 to 2.5 (MRID 46219011, 46219012). As pH in creases, orthosulfam uron residues are expected to becom e increasingly ionized, wh ich is evidenced by th e compound’s increasing water solub i lity and decr easing partitioning to o c tanol at h i gh er pH values

. As orthosu l f am uron ionize s, it is expected to have greater m obility in soil as we ll as greater so lubility in water. The com pound dem onstrates m oderate to slight m obility in soils based upon K f 

### values f r om ten soils ranging from 2.0 (1/n=1.02) to 20 (1 /n=0.98) (MRID 46219074; 46578971). Lack of mobility is p artially explained by affinity to o r gan i c m atter, as the organ i c carbon cont ent of soils corre lates with K f 

### values (p<0.05). T he coefficient of variation (CV) for KOC 

### (115%) is larger than thatf o r

K f 

### (79%) across all ten soils studi ed due to one outlying high K OC 

### value (2330 L/kg OC 

### ) that is likely the result of experim e nt al error. Upon om i ssion of the outlying K OC 

### value from the rem aining nine KOC 

### values (range of 217 – 653 L/kg OC 

### ), the CV for KOC 

### (42%) is less than thatf o r

K f 

### (86%), which is expected when organi c carb on content in soil co rrelates with Kf 

### values. Lack of m obility of orthosulfam u

ron m ay also be partially explaine d by affinity to clay particles, as K f 

### values correlate with the clay content of soils (p<0.05), but not so il pH (p>0.05; pH range 4.7 to 8.0). Affinity to clay m ay be due to io nized congeners of orthosulfam uron. The anionic nature of these congeners would give orthosul fam uron greater mobility than expected f o r the neutral compound alone in hi gh-pH, low-clay soils.
Com pounds with K f 

### values less than five present a ground water concern. Therefore, orthosulfam uron presents a gr ound water concern in som e soils , especially those that are alkaline, sandy, and of low organic carbon content. A column le aching study of aged orthosulfam uro n indicated that som e degradates (DBS acid, DBS am ide, and o-desmethyl orthos ulfam uron) are cap able of great er m obility than the parent and are m ore likely to leach to ground wa ter (MRI D 46219018). Unaged orthosulfam uron ranged from not detected to 2.1% of the applied in five to six pore volum es of leachate from five columns (MRID 46578968). Aged orthosulfam uron was not detected in six pore volum e s of leachate fro mfour soil columns; however, pyrim id inyl-labeled degradates (m ostly o-desm ethyl orthosulfam uron) averag ed 4.6% of the applie d in leachate and phenyl-labeled deg r adates (m ainly DBS acid) averaged 62.5% of the applied in leachate (MRID 46219018). Volatilization of orthosulfam uron from water and so il system s is not expected to be an im portant environm ental fate process based on the com poun d’s water solubility range of 26 m g/L to 39,000 mg/L and vapor pressure of 8.4x10 -7 

### torr, both at 20°C (MRID 46219009; 46219010).
3.3.1.2 Degradation Orthosulfamuron hydrolyzed with half-lives of 0.442, 24.4, and 228 days at 25°C in pH 5, pH 7, and pH 9 buffered solutions, respectively (MRID 46219015, 46578970). The half-life at pH 9 is more uncertain, as it exceeds the study durat ion of 176 days. Majo r identified hydrolysis degradates were DBS acid and DB am ine, as shown in Table 3.8

.

18

### Orthosulfamuron degraded with a calculated phot otransform ation half-life of approximately 180 solar days when irradiated continuously under a f iltered xenon lam p for 6.92 days at 25oC in a pH 9 buffered solution (MRID 46588509). This half -life value was extrapolated far beyond the study duration and is highly uncertain. The e nvironm ental phototransform ation half-life of orthosulfam uron could n o t be determined becau s e the intens ity of the artificial light w a s not com pared to natural sunlight. No m a jor photodegradates were detected. An anaerobic aquatic m e tabolism study was conduc ted for orthosulfamuron using a pond waterloam sedi m e nt system from Arkansas for 180 days and a pond water-clay sedim e nt system from California f or 150 days (MRID 46578967). Half- lives were calculated by counting nonextracted res i dues as parent com pound, since m u ltip le so lvent system s were not em ployed in extraction and non-extractable resi dues in sedim e nt were m easur ed at >10% of applied by day 15. Half-lives in the m i crocosm from Arkans as were 217 and 142 days for pyrim idinyl- and phenyl-labeled orthosulfam uron, respectively. Dissipation occurred m o re rapidly in the m i crocos m from California; half- lives were 161 and 88 days for pyrim idinyl- and phenyl-labeled orthosulfam uron, respectively. Half-lives calculat ed with extracted pare nt com pound alone were 89 and 80 days for the pyrim i dinyl and phenyl labe ls in Arkansas, respectively, and 41 days for both labels in California. The m a jor identi fied degradates were DBS acid, o-desm ethyl orthosulfam uron, and DOP urea, as displayed in Table 3.8

. The aerobic aquatic m e tabolism of orthosulfamuron was also studied using the pond watersedim ent system s from Arkansas and Califor nia (MRID 46219017). Once again, half-lives were calcu lated b ycounting n on-extracted residue s as parent com p ound, since multiple solvent system s were not em ployed in extraction and non- extracted residues reache d 11-33% of applied. Degradation appeared to occur m o re rapid l y under aerob ic co nditions as com p ared to anoxic conditions. Half-lives in the m i crocosm from Arkansas were 70.5 and 59.2 days for pyrim idinyland phenyl-labeled orthosulfam ur on, respectively. Sim ilar to th e anaerobic aquatic m e tabolism study, degradation appeared to occur more rapidl y in the California pond-sedim e nt system ; halflives were 65.4 and 30.3 days for pyrim idinyl- an d phenyl-labeled orthosulfam uron, respectively. It is possible that degradation occurred m ore rapidly in the California system since it was m o re acidic (pH = 6 in sedim e nt) than the Arkansas sy stem (pH = 6.9 in sedim e nt), and hydrolysis of orthosulfamuron appears to be an acid catalyzed reaction. H a lf-lives calc ulated with extracted parent com p ound alone were 40.6 and 36.3 days for the pyrim idinyl and phenyl labels in Arkansas, respectively, and 24.1 and 21.3 days fo r the pyrim idinyl and phenyl labels in Calif ornia, r espectively. The m ajor identif ied degradates were DBS acid and DOP urea, as shown in Table 3.8

. 3.3.1.3 Field Studies A single aquatic field dissipation study was c onducted for orthosulfam uron using a bare ground plot of silt loam soil (pH 6.7) in Arkansas and a bare ground plot of silty clay loam soil (pH 7.7) in California (MRID 46578985). The plots were flooded with water 1–2 days following the application of orthosulfam uron to approxim ate the tim ing of herbic ide a pplication to rice. So il sam p les (0-60 cm depth) were collected thr ough 550-553 days post-treatm ent. W ate r and the underlying soil (“sedim e nt”; 0-5 cm depth) sam p le s were collected from 3 days to 2 months post-treatm ent. At the Arkansas test site, o rthosulfam uron dissipated in the soil (0-15 cm depth),

19

### sedim e nt (0-5 cm depth), and water with half-lives of 4.1 days , 6.2 days, and 6.4 days, respec tive l y. At the Calif o rnia site, o rtho sulf am uron dissipated in the soil (0-15 cm depth) and sedim e nt (0-5 cm depth) with half-lives of 2.3 days and 4.3 days, respectively. No half-life was calcu lated f o r the water phase becau se the ch em i cal was not detected in the water. Both test sites were analyzed for DOP urea, DBS acid, and o-desm ethyl orthosulfam uron. The latter was be low detec tio n lim its in all sam p les f r om both sites. At the Arkansas site, DOP urea and DBS acid were m ajor degrad ates in the so il and sedim e nt; DBS acid was the m a jor degradate in water. At the Calif orn i a site, DOP urea wa s the m a jor degradate in soil and sedim e nt; no m a jor degradates were detected in w ater. 3.3.1.4 Bioconcentration A flow-through bioconcentration study of bluegill sunfish (Lepomis macrochirus ) exposed to orthosulfam uron in pH 7.5-8.0 water for 14 days indicates that the com pound does not bioaccum u late. Bioconcentration factors ( BCF) were 0.29, 0.34, and 0.32 for edible, non-edib le, and whole fish tissues, respectively, in low- dose sam ples (142 μg/L) and 0.72, 1.14, and 0.97 for edible, non-edible, and whole fi sh tissues, respectively, in high-dose sam ples (1420 μ g/L). BCF values less than 1000 do not trigger criteria for b i oaccum ulative com pounds [64 Fed. Reg. 60194-60204 (Novem be r 4, 1999)].
3.3.2 Degradates The transform ation products resu lting from the environm enta l degradation processes of orthosulfam uron are: 2-dim ethylcarbam oylpheny l sulfam ic acid (DBS acid; IR7863; S1); 2­ sulfam oylam ino-N,N-dim ethylbenzam ide (DBS am ide; S2); 2-am ino-N,N-dim ethylbenzam ide (DB am ine; S4); 1-(4-hydroxy-6-m e thoxypyr im idin-2-yl)-3-[2 -(dim ethylcarbam oyl) phenylsulfamoyl]urea (o-desm e thyl orthosulfam uron; IR8181; S9); N-(4,6-dim ethoxypyrim idin2-yl)urea (DOP urea; IR 7825; S 12); 4,6-dim ethoxypyrim idin-2-yl am ine (DOP am ine; S13); and N-(4-hydroxy-6-m e thoxypyrim idin-2-yl)urea (o-d esm e thyl DOP urea; S15). Two other degradation products S5 and S11 are com posed of m u ltiple unresolved co mpounds. DBS acid (S1), DB am ine (S4), o-desm ethyl orthosulfam uron (S9), and DOP urea (S12) were the m ajor degradates ide ntif ied ata m axim um of 62%, 13%, 19%, and 111% of the applied, respectively, detected at 7, 176, 100, and 7 days af ter treatm e nt, respectively. These degradates are m oderately persistent, as peak detections of these degradates occurred at up to 100-186 days after application. None of thes e degradates are known to be toxic, however the o-desm ethyl degradate is assum e d to have equal toxicity as th e parentco mpound because it retain s the parent com pound’s sulfam oylurea structural group. Chem ical structures of these degradation products are shown in Table B of Appendix B

. The m a in de gradation pathway of orthosulfam uron appears to be the hydrol ytic cleavage of the sulfam oylurea linkage to give DOP urea (S12) and DBS acid (S1). Another degradation pathway is the dem e thylation of orthosulfam uro n to its o-desm ethyl degradate (S9), which m ay also degrade to DBS acid. Orthosulfam uron and DBS acid may hydrolyze to form DB am ine (S4). The maxim um am ounts of these degradatio n products observed in hydrolysis, aerobic

20

### aquatic m e tabolism , anaerobic aqu atic m e tabolis m, soil column leaching , and aquatic field dissipation studies are summarized in Table 3.8

. No degradation products were detected in the photolysis study. Degradation products were not analyzed for in the hydrolysis study at pH 5.

T a bl e 3. 8. M a xi mum Rep o r t ed Am oun t s of Orth o s ul f a muron De gr a d ati o n Pro duc ts. 1 Degr ad a t e Ma xi mum% of Ap pl i e d Stud y T y pe MRI D S1 (DB S acid) 58 ( 3 7 d, p H 7) 39 (15 0 d) 61 ( 6 1 d) 25 (55 d); 51 (l eachate) 62 (% of i n itial , 7 d, so il); 23 (% of i n itial , 7 d, sed i m en t ); 34 (% of i n itial , 15 d , water) Hy dr ol y s i s An aero b ic aquatic m e tab o lism Aerob i c aqu atic m e tab o lism Soil columnleaching Aqu atic Field Dissip ation MRI D 4 621 901 5 MRI D 4 657 896 7 MRI D 4 621 901 7 MRI D 4 621 901 8 MRI D 4 657 898 5

S2 (DB S am i d e) 8. 7 (1 1 3 d, p H 9) 4. 2 (1 8 0 d) 4. 0 (6 1 d) 7.2 (34 d); 8.0 (leachate) Hy dr ol y s i s An aero b ic aquatic m e tab o lism Aerob i c aqu atic m e tab o lism Soil columnleaching MRI D 4 621 901 5 MRI D 4 657 896 7 MRI D 4 621 901 7 MRI D 4 621 901 8 S4 

### ( DB am ine) 13 ( 1 76 d , pH 9) 6. 4 (7 1 d) <3 (55 d), 3.7 (leachate) Hy dr ol y s i s An aero b ic aquatic m e tab o lism Soil colum nleaching MRI D 4 621 901 5 MRI D 4 657 896 7 MRI D 4 621 901 8 S5 (m u ltip le unr eso l v e d com pound s) 22 (18 0 d) 2.5 (leachate) An aero b ic aquatic m e tab o lism Soil columnleaching MRI D 4 657 896 7 MRI D 4 621 901 8 S9 

### ( o - desm ethy l ort hos ul fam ur o n ) 19 (10 0 d) 9. 2 (9 0 d) 5.2 (55 d), 4. 6 (leachate) An aero b ic aquatic m e tab o lism Aerob i c aqu atic m e tab o lism Soil colum nleaching MRI D 4 657 896 7 MRI D 4 621 901 7 MRI D 4 621 901 8 S11 (m u ltip le unres o l v e dc o m poun ds) 23 (18 0 d) 0. 26 (l eac hat e ) An aero b ic aquatic m e tab o lism Soil columnleaching MRI D 4 657 896 7 MRI D 4 621 901 8 S12 

### ( DO P ure a ) 19 ( 5 9 d) 47 ( 9 0 d) 36 ( 5 5 d), 52 (so il co lum n ) 38 (s oil column ) 64 (% of i n itial , 186 d , so il); 11 1 (% of in itial, 7 d , sed i m e n t ) An aero b ic aquatic m e tab o lism Aerob i c aqu atic m e tab o lism Soil columnleaching Soil columnleaching Aqu atic Field Dissip ation MRI D 4 657 896 7 MRI D 4 621 901 7 MRI D 4 621 901 8 MRI D 4 657 896 8 MRI D 4 657 898 5

S13 

### ( DOP am ine) 1. 1 (7 1 d) <3 (leachate) 1. 4 (soi l c o l umn ) An aero b ic aquatic m e tab o lism Soil columnleaching Soil columnleaching MRI D 4 657 896 7 MRI D 4 621 901 8 MRI D 4 657 896 8 S15 

### ( o- desm ethy l D O P urea ) 4. 9 (1 5 0 d) <3 (leachate) An aero b ic aquatic m e tab o lism Soil colum nleaching MRI D 4 657 896 7 MRI D 4 621 901 8

1 Perce ntages greater than 10% are i n bol d.


### The toxicities of orthosulfam uron’s m a jor degr adates are not determ ined. The o-desm ethyl degradate is the only degradate that retains the parent com pound’s sulfamoylurea structural group. Therefore, o-desm ethyl orthosulfam uron is assum e d to have equal toxicity as the parent com pound and is of risk concern. The toxicities of orthosulfamuron’s m a jor degradates other than the o

- d esm ethyl degradate are assum ed to be significantly less than that of the parent

21

### com pound because the sulfam oylurea linkag e is se vered. Th erefore, th e com pounds of risk concern for this risk assessm ent are orthosulfam uron parent and its o-desm ethyl degradate. Aquatic exposure estim ates are based on an assumption of no degradation and, therefore, m ay be used to represent exposure to the parent com pound alone or the parent compound and any num ber of its degradates, including its o- desm ethyl degradate of risk concern. No m e thodologies are used to assess terrestrial exposure to o-desm ethyl orthosulfam uron, as its contr i bution to risk is no t expec t ed to alte r te rre strial risk con c lusions thatare based on the fate, transport, and toxicity of the parent com pound alone.
3.3.4 Measures of Aquatic Exposure Rice is grown in paddies that are periodically flooded with several inches of water, an agronom ic practice that m o st surface water m odels currently used for pes ticide risk as sessm ent are not designed to represent. T he Environm ental Fate and Effects Division de veloped the Interim Rice Model to estim ate surface water expo sure to o rtho sulfam uron from use on rice (USEPA, 2002). The m odel e stim ates exposure as a function of the am ount of pesticide applied and the pesticide ’ s s o il- to-water partition coe f f i cient. Re gardless of irrigation pr a ctic e, applic ations are assum e d to occur over a rice paddy flooded with 4 in ches of water. Conc entrations are assum e d to imm e diately and evenly distribute throughout the rice paddy water following application. The application efficiency is assum e d to be 100%; therefore, runoff concentrations do not require adjustm e nt for the contribution of downstream spray drift residues. Dissipation processes, such as degradation, volatilization, and potential d ilution with uncontam inated water outside the paddy are n o t accounted for by the model. The single estimated env i ronm ental concentration (EEC) produced with the Interim Rice Model is used as both an acute an d a chronic s creen ing exposure estim ate that is expect ed to represent high-end exposure in rice paddy water and tail water dis charge (se e Attachment C for calculation). Table 3.9 reports the peak and chronic screening E E Cs used for aquatic risk estim ation.

Table 3.9. Surface waterestimated ex posure conc entrations (EEC) of orthosulfamuron from use on rice. Source App. Rate (lbs ai/A) Peak & Chronic EEC (p pb) Paddywater/tail water 0.06 9 38.6


### In som e soils, particularly in alkaline areas wi th porous soil of low organic carbon content, transpo rt to ground water and subseq uent discharge of ground water to surface water b odies m ay occur. However, expected ground water concentr ations estim ated with the screening m odel SCIGROW (EEC=0.6 ppb) are insignificant com pared to expected surface water concentrations estim ated with the screening Interim Rice Model (EEC=38.6 ppb). Therefore, ground water discharge exposure estim ates are not reported for risk estim ation. The m odel input param e ters used to generate the EEC for paddy water and ta il water listed above are presented in Table 3.10

.

22

### Table 3.10. Interi m Rice Model input parameters for orthosulfamuron. Source data are in Table 3.7. Input Parameter Value Justification Source Application Rate (kg a.i./ha) 0.07 72 0.06 89 lbs a.i ./A x 1.1 21 k g ·A/ha·lbs = 0.077 2 kga.i./ha Proposed label

Soil-to-Water Partition Coefficient (Kd 

### ) (L/kg) 7.19 Mean K OC 

### (359 L/k g OC 

### ) x 2% organic carbon content = 7.1 9 L/k g MRID 46219 074 MRID 46578 971


### Because one K OC 

### value (2330 L/kg OC 

### ) f r om the subm itted s tu d ies wa s an outlier and likely the result of experim e ntal error, the m ean of the nine rem a ining KOC 

### values (359 L/kg OC 

### ) was used to m odel partitioning to rice paddy sedim e nt. In accordance with EFED guidance, the m ean KOC 

### value was multip lied by 2% organic carbon cont ent in o r der to generate the soil-to

- water partition coefficient (Kd 

### ) model input (7.19 L/kg) (USEPA, 2002).
3.3.5Measures of Terrestrial Exposure Orthosulf amuron is prop osed f o r use on rice and will be app l ied by groun d or aer ial s p ray (IR5878 50 WG) or direct dry application by gr ound or air (IR5878 0.5 GR). Measures of exposure for terrestrial organism s can be obtaine d from a variety of sources including monitoring data, field studies, GIS analys is, and exposure modeling. Fo r this assessm ent, exposure modeling was used to generate EECs for both terrestrial anim als and plants. The screening-level assessm ent foc uses on diet ary exposure for terrestrial birds, m ammals, reptiles, and am phibians that m ay com e in cont act with orthosulfam uron use areas. Although other routes of exposure can be im portant, for the m ost part dietary routes of exposure are considered to contribute most to total exposure an d hence are the focus here. Moreover, suitable data ar e f r eq uently unav ailab l e to ad equate lyassess other exposure routs such as derm al, inhalation, or incide ntal soil ingestion.
3.3.5.1 Terrestrial Animal Species Exposure of free-ranging terrestrial anim als is a function of the tim ing and extent of pesticide applic ation with respe ct to the lo cation and behavior of those speci es. O PP’s terrestrial exposure model generates exposure estim ates assum i ng that the anim al is present on the use site at the tim e that pesticide levels are highest. The upper-bound pesticid e residue concentration on food item s is calc u lated f r om both initia l a pplications and any additional app lic ations, takin g into account pesticide degradation be tween applications, however, for orthosulfam uron only one application is required for the proposed use. Although this approach is conservative, it is reasonable, particularly when cons idering acute risks. For acute ri sks, th e assum p tion is thatthe duration of exposure is a single day and, again, occurs when resi due levels are highest. In evaluating chronic risks, longer- term exposure estim ates are also based on the assum p tion that the anim al is present on the use site when resi due levels are highest and furtherm ore that it repeatedly f orages on the use site although the fr equency and duration of foraging events on the use site are not explicitlyconsidered or specified

.

23

### The current screening-level approa ch does not directly relate tim i ng of e xposure to critical or sensitive population, community, or ecosystem processes. Given that the application tim ing and location is c r op-depend e nt, it is dif f i cult to a ddress the tem p oral and sp atial co-o ccurrence of orthosulfam uron use and sensitive ecological processe s. However, pesticides are frequently used from spring through fall; rice cultivation freque ntly starts in the spring, hence uses of orthosulfam uron are likely to occur in spring an d perhaps summer. Spring and early s umm er are typically seasons of active m i grating, feeding, and reproduction for m any w ildlife species. The increased energy dem ands associated with th ese activities (as opposed to hibernation, for exam ple) can increase the potential f o r exposur e to pesticide-contam in ated food item s since agricu ltural areas can represent a co ncentrated s ource of relatively easily obtained, high-energy food item s. In this assessm e nt, the spatial extent of exposure for terrestrial anim al species is lim ited to th e use area o n ly and the area imm e di ately surrounding the us e area. S i nce the m ajority of applied o rth osulf am uron will likely f all within th e ric e paddy , direc texpo sures to terr estria l an im al species will r esult e ithe r f

r om sp ray drif t o r , in the c ase of granules, applic ation to non-target areas. It is likely that for aer ial application of granul es, the boundary regions between pad d ies m ay receive app lications of ortho s ulfam uron sim ilar to wh at is b eing applied to the rice paddy. In addition, given th at orthosulfamuron is applied dire ctly to water, it is possible that terrestrial anim als that consum e fish and aquatic invertebrates m ay be exposed to orthosulfam uron that has bioaccum u lated in thes e types of aq uatic o r ganism s. Currently, the Agency does not re quire toxicity studies on reptiles and am phi bians in support of pesticide reg i strations. T o accomm odate th is data gap, birds are used as s urrogates for terrestrial-p h ase am phibians and reptiles. It is assum e d that, given the usually lower m e tabolic dem ands of reptiles and am phibians com p ared to bi rds, exposure to birds would be greater due to higher relative food consum ption. While this assum ption is likely true, there are no supported relationships regarding the relativ e toxicity of a com pound to bird s and herpetofauna. The lack of toxicity data on reptiles and am phibians repr es ents a sour c e of uncerta inty in th is as sessm ent. 3.3.5.1.1 Terrestrial Animal Exposure Modeling The approach used to estim ate exposure of terr estrial anim als to orthosulfamuron was based on potential foliar applications of IR5878 50 W Gand dry granule applications of IR5878 0.5 G to non-target areas. These non-target areas ar e the dry paddy embankm e nts and divisions imm ediately adjacent to the treated p addy and ch aracteristic of rice cu ltiv ation areas; this represents a reasonable upper-bound exposure a terrestrial species m ay likely receive from foliar applications of orthosulfam uron. The s e exposure estim ates were determ ined using the standard screening-level exposure m ode l, TREX (v1[1].2.3) (USE PA, 2004). Upper-bound exposure levels were calcu lated f o r spray and granular applications of orthosulfam uron using m axi m um proposed application rates for one app lication for the proposed use on rice ( Table 3.11 ). The exposure estim ates for the water dispersible gr anule form ulation are based on a database of pesticide residues on wildlife food sources associat ed with specified application rates (Kenaga, 1972; Fletcher et a l ., 1994). Essentially, for a single appl ication, there is a linear relationship between the am ount of pesticide applied and the amount of pestic ide residue present on a given food item

. For 1.0 lb a.i. of pesticide per acre, the upper-bound, food item concentration in m g a.i./kg of diet (parts per m illion [ppm]) is: 240 for short g r as s, 110 for tall grass, 135 for broadleaf plants and sm all insects, and 15 for fr uits pods, and large insects. Food item residue

24

### levels are then linearly adjusted based on app lication rate. T h e upper-bound estim ates are used to estim ate risks sin ce th ese valu es represent the h i gh-end exp o sure that may be encountered for terrestrial species that consum e food item s thathave received label-specified pesticide application. Although these repr esent higher-end estim ates, they do not represent the highest possible exposure estim ates. For the granular formulation, the LD 50 

### /f t 2 

### was used. This m e thod com p ares the averag e co ncentration in a square f oot of the use area to the LD 50 

### and is a rough estim ate of exposure tak i ng into acco unt m u ltiple exposure pathways. In addition, b i rd s can consum e granules directly, either as a result of inci dental ingestion or purpos ef ully in anef f o rt to acquire grit to facilitate digestion. Quantifying the num ber of granules consum ed in relation to the LD 50 

### provides a sense of the potential effects associated w ith this route of exposure. TREX is a sim ulation model that, in addition to incorporatingthe re lation ship betwee n application rate and food item re sidue concentrations, accounts fo r pesticide degradation in the estim ation o f EECs. TREX calculates pesticid e residues on each type of food item on a daily interval for one year. Afirst-o r der d ecay functio n is used to calcu late the residue con centration at each d ay based on the concentrations present fr om both initia l and all s ubsequent a pplications, although for orthosulfam uron only one application is proposed. The decay rate is dependent on the foliar dissipation half -life. The food item c oncentration on any given day is the sum of all concentrations up to that day, taking into acc ount the first-order degradation. The initial application occurs on day 0 (t=0 ) and the m odel runs for 365 days. Over the 365-day run, the highest res i d u e concentration is the m easure of exposure (EE C ) used to calculate RQs. The foliar dissipation half-life can be im portant in estim ating exposure because it essentially determ ines how long the pesticide rem a ins on food item s after application. In m any cases, an em pirically determ ined f o liar diss ipation ha lf -lif e value is not available, in which case the default value of 35 days is used (W illis and McDowell, 1987). For orthosulfam uron, the def ault foliar dissipation half-life was used. Although the focus of exposure estim ates for this assessm ent is the dietary route, other exposure routes including derm al and inhala tion can be important contributors t o ove r a ll e xpos ur e l e ve l s
. For orthosulfam uron, derm al and inhalation exposure m ay only be expected for use of the water dispersible granule form ulation si nce dry granules are too large to be inhaled and are unlikely to contribute to derm al exposures. These alternate r outes of exposure, however, were not explicitly incorporated into estim ates of exposure for the water dispersible granule form ulation of orthosulfam uron; using only the d i etary route to assess po tential effects likely cap tures the potential for adverse effects. Mo reover, since orthosulfam uron is anherbicide, it is probably not very tox i c to terrestrial anim al species and, in ad d ition, d r oplet size is likely to be larger further reducing the potential fo r advers e effects as soci ated with derm al or inhalation exposures. Table 3.11 lists EECs for birds, reptiles, terrestr ial am phibians, and m amm als obtained from TREX si m ul ation for all proposed uses of orthosulfam uron a tthe m aximum label rates.

25

### Table 3.11. Terrestrial Food-Item Resi due Estimates for Orthosulfa muron Proposed Uses Assuming a Foliar Dissipation Half-life of 35 Days.
Crop Si ngl e Appl i c at i on Rate lb s. a.i./A (1 ap pl i cat i on onl y ) Food Item M ax i mu m E E C (m g/kg) 1
I R 58 78 50 WG

R i ce 0. 06 9 Sh ort gra ss 16 .5 6 Tal l grass 7. 59 B roa dl eaf pl ant s / sm al l i n sects 9. 32 Fru its, pod s, seed s, lg . in sects 1

. 0 4 I R 58 78 0

. 5 G R i ce 0. 06 6 0. 69 m g a.i ./ ft2



### . 3.3.5.2 Terrestrial Plant Species Exposure of naturally-occurring te rrestrial and sem i -aquatic (wetland) plant species is typically estim ated using OPP’s TerrPlant (v1.2.1) m odel and is assum e d to encom p ass areas outside the imm e diate use site. For non-wetland areas, expo sure calculations are based on the amount of pesticide p r e sent in so il a s a f unc tion of drift. Loading via drift to dry, non-target, adjacent areas is assum e d to occur from one acre of treatm e nt to one acre of the non-target area. In wetland areas, pesticide loading occurs from tail water release of rice pa ddy water. This is a departure from what TerrPlant calculates but better represents the proposed use of orthosulfam uron. In this case, water from the tail water release is assum e d to reach sem i -aquatic areas and the exposure level is equ i valent to the EEC calculated us ing th e Interim Rice M odel. S p ray drift is also a source of pesticide loading to non- target areas. The default spray drift assum ptions are 1% for ground applications and 5% for aerial, airblast, for ced air, and chem igation applications. Drift is not considered for form ulations of pe sticides that are not spray-applied ( e. g. , granules). 3.3.5.2.1 Terrestrial an d Semi-Aqu atic Plan t Exposure Modeling Orthosulfamuron exposure to te rrestrial and sem i -aquatic plants was estim ated using OPP’s TerrPlant (v1.2.1) m odel and the Interim Rice M odel. TerrPlant generates EECs for plants residing near a use area that m ay be exposed via spray drift, as explained above. The EECs are generated from one application at th e m axi m um rate for a p artic ular use and com pound-specific solubility in form ation. Only a single applicatio n is consid ered because it is assum ed that for plants, toxic effects are likely to m anif est shortly af ter the initial exposure and that subsequent exposures do not contribute to the response. Th e label for the proposed use of orthosulfam uron on rice indicates that only one application per season is allowed. TerrPlant estim ates EECs based on application rate, solubi lity factor and default assum ptions of drift. The EECs for terr estria l an d sem i -aquatic p l ants f o r

a single app lication of th e water d i sp ersib l e gr anule form ulation of orthosulfam uron at the m axi m um label rate for proposed uses are presented in Table 3.12

. The Inte rim Rice Model was used to estim ate ta il water lo ading to sem i -aquatic areas (see in puts inTable 3.10 and calculation in Appendix C ). Although the EECs in Table 3.12 are specific to the water disp ersible g r anul e form ulatio n, these EE Cs are sim i lar to what would be estim ated from TerrPlant for the dry granule form ul ation. Moreover, for dry granule application, the two exp o sure rout es are from sh eet and/o r ch annelized runoff. Because of the

26

### proposed use on rice, the tail water release expos ure estim ate from the Interim Rice Model is like l y the be st rep r esentation f o r exp o sure asso ciated with th e dry granu l e use. Table 3.12. EECs for Terrestrial and Semi-Aqua tic Plan ts Near Orthosulfamuron Use Areas.

Crop Single Max. Application Rate (lbs a. i./A) EECs (lbs a.i./A) (Ground Spray, Aerial Spray) Total Loading to Sem i

Aquatic Areas Drif t EEC

Tail wate r re lease Ground spray Aerial sp ray Rice 0.069 0.0367 0.0007 0.0035
3.3.5.3 Residue Studies Environm ental residue studies can also provide useful info rm a tion regarding the potential exposure of terrestrial wildlife and plant species in and around use ar eas. These data can be used to corroborate m odeling results or to provide additional insights into chemical fate with respect to exposure. For orthosulfam ur on, no studies are available; all estim ates of exposure are based on m odel outputs.
3.4. Ecological Effects Characterization In screening

- level eco lo gical risk as sessm ents, effects characterization describes the types of effects a pes ticide can have on a quatic and terrestrial organism s. This charac ter i zatio n is based on regis trant -subm itted s tudies that d escrib e inf o r

m ation regar d ing acute and chronic toxicity effects for various aqu atic and terres trial an im als and acute studies on aqu atic and te rr estr ial plants. Appendix E summarizes th e results of a ll r egis trant

- subm itted to xicity stud ie s used to characterize effects for this risk assess m e nt wh ile only those toxicity e ndpoints used in risk estim ation are presented here. Toxicity testing reported in this section do es not rep r es ent all species of birds, m amma ls, or aquatic organism s. Only a few surrogate species for both freshwater fish and birds are used to represent all freshwater fish (2000+) and bird (680+) species in th e United States. For m ammals, acute studies ar e usually lim ited to the Norway rat o r the house m ouse. Estuarine/m arine testing is usually lim ited to a crustacean, a m ollusk, and a fish. Im portantly, results from subm i tted toxicity studies are n o t lik ely to capture the toxicity of orthosulfam uron to all species of birds, m ammal s , plants, or aquatic anim als. Furtherm ore, there are no currently required toxicity tests for am phibian or reptiles; birds are used as surrogates for reptiles and terr estria l-p h ase am phi bians and fres hwater fish are used as surrogates for aquaticphase am phibians. In general, the representati on of num e rous species by a few commonly used laboratory s pecies, which are often chosen for th eir ab ility to thriv e under laboratory conditions, is a source of uncertainty. Orthosulfamuron is, for the m ost part, practica lly non-toxic to slightlytoxic to birds and honeybees under acute exposure con d itions. In addition, there were no significant effects of orthosulfam uron on survival, growth, or reprodu ction in submitted avian reproduction studies.

27

### Sim ilarly, for aquatic an im al species (fish and invertebrates), orthosulfam uron is classified as practically n on-toxic to s lightlytox i c under acute exposure co nditions. Th e few chronic toxicity studies involving exposure to aquatic organism s also indicate that orthosulf am uron is not particularly toxic, although NOAE Cs were established in these studies. In contrast to the toxicity to anim al species, orthosulfam uron is very highlytoxic to aqu atic p l ants and exhibits significant toxic ity tow ards te rr estrial plant spec ies as well

. Given the intended use of orthosulfamuron as an herbicide, these results are not unexpected. It seem s likely that any potential environm ental risks of orthosulfam uron could be focused on direct effects to plants and p o tential indirect ef f ects on anim al species d epen d ent on plant species. In addition to the data su bm itted in s upport of registration, th e EC OTOX (ECOTOXicity) database was used to identify additional toxici ty data from the open literature. The E C OTOX databas e is a user-f riendly, public ly-availab l e, qua lity -assured, com p rehensive too l f o r locating toxicity data from the open lite rature and is m a intained by EP A Mid-Atlantic Ecology Division. More inform ation on E C OTOX can be found at: http://www.epa.gov/ecotox. Research papers are thoroughly screened using standard procedur es before being accepted into ECOTOX thereby ensuring consistent, high quality inform ation. Fo r orthosulfam uron, no studies were identified in ECOT OX.
3.4.1. Aquatic Effects C h aracterization The m ost sensitiv e acute and chronic effect s m ea surem ent endpoints as so ciated with orthosulfam uron exposure to fr eshw ater and estuarine/m arine species are summarized in Table 3.13

. All effects m easurem ent endpoints used to assess the potential risk s of orthosulfam uron exposure are obtained from studies using technical grade orthos ulfam uron or orthosulfam uron form ulated product. No studies u sin g orthosul famuron degradates were s ubm itted. Appendix E provides a more detailed summary of all aquatic toxicity studies available for estimating and characterizing potential risks associat ed with orthosulfam uron use on rice. Results of acute toxicity studies i nfreshwat e r fi sh, freshwat er invertebrates, estuarine/m arine fish, and estuarine/m arine invertebrates (shrim p and crustaceans) indicate that orthosulfam uron is not m ore than slightly toxic on an acute basi s. Acute toxicity valu es for freshwater and estuar ine /m arine spe cie s indicate th at estuar in e/marine fish are sim ilarly sensitive to orthosulfam uron. For orthosulfam uron, no subletha l effects were observed in freshwater or m arine/estuarine fish during acute exposures. No acute toxicity studi es of orthosulfam uron form ulations were available for freshw ater fish or invertebrates or estu arine/m arine fish or invertebrates. Chronic tox i city s tudies are availab l e for freshwat er fish and invertebrates and estuarine/m arine invertebrates. There were som e effe cts of orthosulfam uron on survival in the chron i c toxic ity studies although lowest effect leve ls were associated with decrease d growth. In freshwater fish, the only chronic effect was a reduction in dr y w e ight in fathead m i nnow observed during a 33-day chronic toxicity study. In freshwater invertebrates, effect s on growth and first-generation survival were observed in a 21-day life-cy cle toxicity study with the water flea.

28

### Results of acute toxicity studies of orthosulfam uron form ulations in fres hwater and m arine algae and aquatic m acrophytes indicate th at orthosulfamuron is highly t oxic to very highly toxic to aquatic plants.

Table 3.13. Orthosulfamuron Toxicity Measur ement Endpoints for A q uatic Organisms.

Exposure Scenario Species Exposure Duration Toxicity Referenc eValue Refe renc e (Classification)
Freshwate r Fish A c ute Rainbo w tr out 9 6 hour s LC 50 >1 22 m g a.i./L MRI D 4 621 904 2 (Acce ptable ) Chronic Fathead m i nno w 3 3 d ays N O A E C ( dry w e igh t) = 6.1 m g a.i./L MRI D 4 657 895 3 (Acce ptable ) 

### Freshwate r I n vertebrate s Acute Water flea 48 h o urs EC 50 >9 7.3 m g a.i./L (m o rtality/i mmo b ility) MRI D 4 621 904 4 (Acce ptable ) C hr oni c Wat e r fl ea 21 day s NO AEC (t ot al l e ngth ) = 6 .5 m g a.i ./L M RID 46 5 7 8 9 56 (Acce ptable ) 

### Estuarine/M a rine Fish Acute Shee ps head m i nno w 9 6 hour s LC 50 >1 23 m g a.i./L MRI D 4 657 895 1 (Acce ptable ) C hr oni c No st u d i e s wer e su bm i tt e d



### Estuarine/M a rine Inverte b rates Acute Eastern oyster 96 hours EC 50 >9 7 m g a.i./L MRI D 4 657 895 7 (Acce ptable ) Acut e M y si d shri m p 96 h o urs LC 50 >1 22 m g a.i./L MRI D 4 657 895 2 (Acce ptable ) C hr oni c M y si d shri m p 29 day s NO AEC =2 7 m g a.i ./L M RID 46 5 7 8 9 54 (Su p p lem e ntal) 

### Aquatic Plants M acro phyt e s Duc k weed 7 day s EC 50 ( f r ond num b er ) = 0.0007 m g a.i./L N O A E C = 0.00 026 m g a.i./L MRI D 4 657 893 9 (Acce ptable )
Fres hwate r Algae a Navicula p e llicu lo s a 9 6 hour s EC 50 ( b i o m ass) = 0.8 m g a.i./L NO AEC =0

. 2 8 m g a.i./L MRI D 4 657 893 5 (Su p p lem e ntal) Mar i n e Algae a Skeletonema cost atum 9 6 hour s EC 50 ( b i o m a ss) = 0.08 m g a.i./L N O A E C = 0.02 1 m g a.i./L MRI D 4 657 893 6 (Su p p lem e ntal)



### 29

### 3.4.1.1 Aquatic Animal Species

3.4.1.1.a. Aquatic Animals: Acute E ffects
Freshwater Fish The acute to xicity of technical grade orthosulfam uron to freshwat er fish was evalu ated in two species, with 96-hour L C 50 

### values of >122 m g a .i./L in rainbow trout (MRID 46219042) and >142 m g a.i./L in bluegill sunfish (MRID 46219043). No m o rtalities were observed in controls or treated groups for both studies. B a sed on thes e results, orthosulfam uron is categorized as practically nontoxic to freshwater fish on an acute exposure basis. Taking the m ost conservative approach, the lowest 96-hour LC 50 

### of >122 m g a.i ./L in rainbow trout is used to evaluate acute toxicity for freshwater vertebrates. No studies assessing the acute t oxicity of orthosulfam uron formulations or degradates in f r eshwater f i sh were sub m itted. Freshwater Inverteb rates An acute toxicity study of technical grade or thosulfam uron in the water flea (MRID 46219044) yielded 48-hour EC 50 

### and NOAEC values (where immobility was interpreted as lethality) of >97.3 m g a.i ./L and 47.0 mg a.i./L, respectively, indicating that orthosulfamuron is classified as slightly tox i c to freshwater invertebrates on an acute exposur e basis. The 48-hour m o rtality was 20% in the 97.3 m g a.i./L group (highe st concentration tested). The EC 50 

### of >97.3 m g a.i./L for mortality an d immobility in the water f l ea will b e used to as s e ss the a c ute risk to f r e shw ater invertebrates. An acute toxicity study of technical grad e orthosulfam uron in crayfish (MRID 46578955) yielded 96-hour LC 50 

### and the NOAEC values (both for m orta lity and sublethal effects) of >129 and 129 m g a.i./L, respectively, indicating that orthosulfam uron was practic ally nontoxic to the crayfish on an acute basis. Although the latter study was not conducted in a U.S. EPArecomm ended species for toxicityte sting withf r eshwater inv e rtebrates and guidelines do not exist for this species, the study is scientifically sound and it pr ovides support for the toxicity category established in the study in the water flea (MRID 46219044). No acute toxicity studies of orthosulfam uron formulations or degradates in freshwater invertebrates were submitted.
Estuar ine/M arine F i sh The acute to xicity of technical grade orthosulfam uron to estuarin e/m arine fish was evaluated in the sheepshead m i nnow ( M RID 46578951). The study reported a 96-hour LC 50 

### >123 mg a.i./L, indicating that orthosulfamuron was practically nontoxi c to estuarine/m arine fish on an acute exposure basis. No sublethal effects were observed in sheepshead m i nnow exposed up to 123 mg a.i./L. The 96-hour LC 50 

### of >123 m g a.i./L in sheepshead m i nnow will b e used to evaluate the acute toxic exposure of estuarin e/m arine fish to orthosulfamuron.

30

### No acute toxicity studies of orthosulfam uron formulations or degrad ates in estuarine/m arine fish were subm itted.
Estuar ine/M arine Invert e b rates Acute toxicity tests with estuarine/m arine i nvertebrates exposed to technical grade orthosulfam uron were conducted in eastern oys ter (MRID 46578957) and mys i d shrim p (MRID 46578952). No effect on shell deposition or incr eased m o rtality were observed in an acute toxic ity (96

- hour) te st in the eas tern o y ster exposed to orthosulfam uron TGAI, yielding a 96-hour EC 50 

### >97 m g a.i./L. These results indicate that orthosulfam uron is characterized as slightly toxic to estuarine/m ari ne m o llusks. An acute toxicity study of orthosulfam uron in the mysid shrim p reported a 96-hour LC 50 

### >122 m g a
. i./L, indicating that orthosulfam uron is practically nontoxic to estuarine/m arine invertebrates on an acute exposure ba sis; no sublethal ef

f ects were observed. E F ED will use the EC 50 

### value of >97 mg a.i./L to assess acute risk to estuar ine /m arine m o llusk s and the LC 50 

### value of >122 m g a.i./L to assess acute risk to estuarine/m arine shrim p. No acute toxicity studies of orthosulfam uron formulations or de gradates in estuarine/m arine invertebrates were submitted.



## 3.4. 1.1. b. A q u a tic Ani m als: Chr o nic Effects
Freshwater Fish A 33-day, early life-s t ag e toxicity s t udy of orthosulfam uron in fathead m i nnow was subm itted by the reg i strantto es tablishthe chron i c toxic ityof orthosulfam uron to freshwat er fi sh (MRID 46578953). Fish were monitored for em bryo surviv al, larval survival, term inal length, dry weight, wet weight, and clinical signs of toxicity. The reported NOAE C and LOAEC values of 6.1 and 13 mg a.i./L, respectively, were based on decreased dry weight m easurem e nts, the only endpoint affected. The 33-day NOAEC value of 6.1 m g a.i./L for sublethal effects on growth will be us ed to asses s the risk of chro nic e xposure of freshwater fi sh to orthosulfam uron. No chronic toxicity studies of orthosulfam uron form ulations or degrad ates in freshwater fish were subm itted. Freshwater Inverteb rates A 21-day life-cycle tox i city s tudy with orthosulf am uron in the water flea was subm itted by the regis trantto estab lish the chroni c toxicity of orthosulfam uron to freshwater invertebrates (MRID 46578956). First-generation survival, reproduction, to tal length, dry weight, and sublethal signs of toxicity w e re assessed. NOAE C and LOAE C values of 6.5 and 14 m g a.i./L, respectively, were established based on reductions in m ean tota l length. In addition, fi rst-generation survival was reduced at the highest concentration tested (E C 50 

### >105 mg a.i./L; LO AEC = 105 mg a.i./L; NOAE C = 5 2 m g a.i./L). Reproduction and dry wei ght were not affected at any concentration tested. The NOAEC of 6.5 m g a.i./L (effect on total length) will be used to assess chronic risk of exposure of aquatic inverteb rates to orthosulfam uron.

31

### No chronic toxicity studies of orthosulfam uron form ulations or de grad ates in freshwater aquatic invertebrates were submitted.
Estuar ine/M arine F i sh No chronic toxicity tests in estuarine/m arine fish with orthosulfam uron, form ulations, or degradat es were subm itted.
Estuar ine/M arine Invert e b rates One lif e-cyc l e (29-d ay) toxicity stud y in the my sid shrim p was subm itted to establish the chron i c toxicity of orthosulfam uron to estuarine/m arine invertebrates (MRID 46578954). NOAEC and LOAEC values of 27 and >27 m g a.i ./L, respec tively, were established for orthosulfamuron TGAI based on the absence of effects on m orta lity, reproduction, or growth after 29 days. The NOAEC of 27 m g a.i./L will be used to characteri ze chronic risk to estuarine/m arine invertebrates exposed to orthosulfamuron. No chronic toxicity studies of orthosulfam uron form ulations or degrad ates in estu arin e/m arine invertebrates were submitted. Benthic Organism s No toxicity studies of orthosul fam uron TGAI, form ulations, or de gradates in benthic organism s were subm itted.

3.4.1.1.c. Aquatic Animals: Sublethal Effects
Freshwater Fish In addition to lethality endpoints, sublethal e ffects of orthosulfam ur on TGAI exposure were assessed in acute toxicity st udies in rainbow trout (MRID 46219042) and bluegill sunf ish (MRID 46219043) and in a chronic toxicity study in fathead m i nnow (MRID 46578953). No signs of sublethal toxicity were observed in acute toxicity studies, withNOAEC values in rainbow trout and bluegill sunfish of 122 m g a.i./L and 142 m g a.i./L, respectively. The only sublethal effect observed in the chronic exposure study in fa thead m i nnow was a redu ction in dry weight (NOAEC = 6.1 m g a.i./L; LOAEC = 13 m g a. i./L) (MRID 46578953). No effects on em bryo surviva l , lar v al surv ival, term inal len g th, wet wei ght, or clinical signs of toxicity were observed. Freshwater Inverteb rates Sublethal effects of acute orthos ulfamuron TGAI exposure were a ssessed in a study of the water flea (MRID 46219044) and crayfish (MRID 46578955). No sublethal effects were observed in either study, with NOAE C values for water flea and crayfish of >97.3 m g a.i./L and 129 m g a.i./L, r e spe c tive l y. Subletha l ef f ects in th e total le ngth and dry weight were observed in a 21 -day life-cy cle toxic ity study with water flea (MRID 46578956). NOAEC and L OAEC valu es of 6.5 and 14 m g a.i./L, respec tive l y, were established based o nreductions in m ean total leng th ( th e m o st sensitive endpoint). Reproduction and dry weight were not affected atany of the doses tested.

32

### Estuar ine/M arine F i sh No acute sublethal effects were observed in sheepshead m i nnow exposed to orthosulfamuron TGAI at 123 m g a.i./L. Thus, a NOAEC = 123 mg a.i./L for acute sublethal effects was reported (MRID 46578951). No chronic toxicity studies in estuarine/m arine fish with orthosulfam uron were subm i tted, thus, no inf o rm ation is ava ilab l e reg arding the s ublethal effects of chronic exposure of estuarine/m arine fish to orthosulfam uron. Estuar ine/M arine Invert e b rates No sublethal effects were observe d in acute toxicity studies of orthosulfam uron TGAI in the eastern oyster (MRID 46578957) or mysid shrimp (MRID 46578952), yielding 96-hour NOAE C values of 97 m g a.i./L and 122 m g a.i./L, respectively. No sublethal effects on survival, growth, reproduction, or clinical signs we re reported in a life-cycle toxici ty study of orthosulfam uron in the mysid shrim p (MRID 46578954), yielding NOAEC and L OAEC valu es of 27 and >27 m g a.i./L, r e spe c tive l y. Benthic Organism s No studies were subm itted of orthos ulf am uron T GAI, f o rm ulations, o r de gradate toxicity in benthic organism s.

3.4.1.1.d. Aquatic Animals: Field Studies
Subm itted studies f o r orthosulf am uron did not in c l ude aquatic f i eld stud ies.

3.4.1.1.e. Plants Inhabiting Aquatic Areas
Studies wer e subm itted f o r a f r eshwater v ascular plant (duck w eed, Lemna gibba ), blue-gre en algae ( Anabaena flos-aquae) , a freshwater diato m(Navicula pelliculosa ), a green alg ae ( Pseudokirchnerie lla subcapitata form erly known as Selenastrum capricornutum ), and a m arine alga ( Skeletonema costatum ) exposed to the formulated product, IR5878 50W G(water dispersible granule form ulation) containi ng approxim ately 50% orthosulfam uron. Orthosulfamuron (TEP) was very highly toxic to duckweed as indicated by reductions in frond num ber observed in two Ti er II, 7-day studies. E C 50 

### values of 0.7 μg a.i./L (MRID 46578939) and 0.75 μg a.i./L (MRID 46578940) were reported; the associated NOAECs were 0.26 μg a.i./L and 0.22 μg a.i./L, respectively. The EC 50 

### value of 0.7 μg a.i./L and the NOAE C of 0.22 is used to assess the risk of orthosulfam uron to aquatic m acrophytes. Tier II acute (96-hour) toxici ty tests in freshwater nonva scular plants (MRID 46578931; 465789­ 34; 46578959; 46578937; 46578938; 46578932; 46578935) resulted in 96-hour EC 50 

### va l u e s ranging from 0.8 m g a.i./L for reductions in biom ass in Navicula pe llicu l osa (MRID 46578935) to >54 m g a.i./L for the absence of effect s on cell density, growth rate, or biom ass in Navicula pelliculosa (MRID 46578932). The lowest EC 50 

### value of 0.8 mg a.i./L and the associated

33

### NOAE C of 0.28 m g a.i./L for reductions in biom ass in Navic ula pellicu l o s a are used to assess the risk of orthosulfam uron to freshwater algae. Im portantly, this study incorporated an adjuvant into th e tr eatm ents to simulate a possible tank m i xture for orthosulfam uron. The adjuvant control for this study showed hi gh inhibition indicating an effect due to the adjuvant alone. Because it is likely that an adjuvant would be used to im prove the efficacy of orthosulfam uron, toxicity endpoints based on these studies were co nsidered suitable for risk assessm ent purposes although som e uncertainty exists concerning the relative toxicity of the adjuvant and the active ingredient. Tier II acute (96-hour) toxici ty tests in the m arine diatom (MRID 46578936; 46578933) resulted in EC 50 

### values from 0.08 m g a.i./L for reductions in biom ass in Skeletonema costatum(MRID 465789-36) to 12 m g a.i./L for reductions in biomass in Skeletonema costatum(MRID 46578933). The EC 50 

### value of 0.08 mg a.i./L and the associated NOAEC of 0.021 m g a.i./L for reductions in biom ass in Skeletonema costatum(MRID 46578936) will b e used to as s e ss the risk of orthosulfam uron to marine plants. Sim ilar to the study on Navicula pelliculosa described in the previous paragraph, an adjuvantwas also added for this study on Skeletonema costatum , likely sim u lating a tank m i xture for orthosulfam uron. Again, since it is likely that an adjuvant would be used to im prove the efficacy of orthos ulfam uron, use of these toxicity endpoints is considered reasonable for this asses s m ent. Based on the data, orthosulfam uron is classified as very highly toxi c to aq uatic p l ants on an acute exposure basis.

3.4.2. Terrestrial Effects Characterization The m o st sensitiv e acute and chronic toxic ity r ef erence va lues associat ed with orthosu l f am uron exposure to m ammals, birds, and terre strial plants are summ arized in Table 3.14

. An acute oral toxicity study in rats indicates that orthosulfam ur on is practically non-toxic to rats on an acute oral exposure basis with an LD 50 

### > 5000m g/kg (MRID 46219019). A chronic, two-generation reproduc tive study in rats showed thatorthosulfam uron resulted in som e toxicological effects. The m os tsensi tive endpoints were increas ed incidence of kidney lesions in adult rats and decr eased motor activity in F1 m a les; the NOAE C for both endpoints is 88.6 m g/kg/day. Studies of acute oral (dose-based) toxicity in m a llard duck and bobwh ite quail indicate that orthosulfamuron is not more than slightly toxic to m a llard duck or bobwhite quail when adm i nistered a single oral dose. A subacute di etary toxicity study showedthat orthosulfam uron TGAI is not more than slightly toxic to m a llard duck and bobwhite quail on a subacute dietary exposure basis. No acute oral or dietary toxici ty studies of orthosulfa m uron form ulations or degradat es in avian spe c i es were sub m itted.
No treatm e nt-related effects on adult bird m ortality, food consum ption, body weight, or reproductive param e ters and no clini cal signs or treatm e nt-related eff ects in offspring survival or

34

### body weight were observed in chronic studies of reproductive toxicity of orthosulfam uron in m a llard duck and bobwhite quail. No chronic toxi city studies of orthos ulfam uron form ulations or orthosu l f am uron degradates in avian species were subm itte d. Results of available toxicity studies indicate th at orthosulfam uron is practically nontoxic to honey bees on an acute contact basis. Tier II seedling em ergence and vegetative vigor studies with orthosul fam uron form ul ations (49.96% a.i.) in terrestrial plants sh owed reductions in dry w e ight (EC 25 

### ) in both m o nocots and dicots at application rates of 0.0048 lbs a.i./A and 0.00012 lbs a.i./A, respectively.

Table 3.14. Orthosulfamuron Toxicity Measur ement Endpoints for T errestrial Organisms. Exposure Scenario Species Exposure Duration Toxicity Referenc eValue Refe renc e (Classification) Ma mma ls Acute (D ose- base d) Lab o rat o ry rat Si ngl e o r al d o s e LD 50 > 50 0 0 m g a.i ./kg bw M RID 46 2 1 9 0 19 Accepta ble C hr oni c (Dietary

- b ase d) Lab o rat o ryrat Tw o- gene rat i o n NO AEC =8 8

. 6 m g /kg/ day NO AEL = 14 0 0 ppm MRI D 4 621 903 3 Accepta ble 

### Birds Acute (D ose- base d) Bo bwh ite qu ail and m a llard duc k Single oral dos e LD 50 >1 960 mg a.i./ k g bw MRI D 4 626 010 7 (d

uc k; Acce pt a b l e ) MRI D 4 626 010 8 (qu ail; Accep t ab le) Acute (Dietary

- b ase d) M a l l ard d u c k 8- day di et ary LC 50 >4 790 mg a.i/kg d iet MRI D 4 621 904 0 (Acce ptable ) C hr oni c (Dietary

- b ase d) Bo bwh ite qu ail and m a llard duc k Avian r e pr odu ctio n st

udy N O A E C = 1280 m g a.i./kg d i et MRI D 4 657 894 9 (d

uc k; Acce pt a b l e ) MRI D 4 657 895 0 (qu ail; Accep t ab le) 

### Terr est rial Invertebrate s Acute (Co ntact) Ho neyb ee 48

- h o ur LD 50 >1 00 μg a.i./b ee MRI D 4 621 904 6 (Acce ptable ) Acute (O ral) Ho neyb ee 48

- h o ur LD 50 >1 09 .4 μg a.i./ b ee MRI D 4 621 904 6 (Acce ptable ) 

### Plants – Seedling Emerg ence Monoc o t Rice Single ap p lication EC 25 (drywei g ht) =0 .0 7 8 lbs a.i./A N O A E C = 0.01 5 lb s a.i./A MRI D 4 657 894 1 (Acce ptable )

Di cot R a di sh Si ngl e ap p lication EC 25 (drywei g ht) =0 .0 4 0 lbs a.i./A N O A E C = 0.01 5 lb s a.i./A MRI D 4 657 894 1 (Acce ptable ) 

### Plants – Vegetative Vigor M o n o c o t Oni on Si ngl e ap p lication EC 25 ( dryw e i g h t) = 0.004 8 lbs a.i./A N O A E C = 0.00 169 lbs a.i./ A MRI D 4 657 894 2 (Su p p lem e ntal)



### 35

### Table 3.14. Orthosulfamuron Toxicity Measur ement Endpoints for T errestrial Organisms. Exposure Scenario Species Exposure Duration Toxicity Referenc eValue Refe renc e (Classification) Di cot C arr ot Si ngl e ap p lication EC 25 ( dryw e i g h t ) = 0.000 12 lb s a.i./A N O A E C = <0.0 000 64 lb s a.i./A EC 05 = 0

. 00 002 7 lb s a.i./A MRI D 4 657 894 2 (Su p p lem e ntal)



### 3.4.2.1. Terrestrial Animals

3.4.2.1.a. Terrestrial Animals: Acu te Effects
Birds Acute oral (dose-based) toxicity studies of orthosulfam uron i n m a llard duck (MRID 46260107) and bobwhite quail (MRI D 46260108) were sub m itted. Single oral doses as high as 1960 m g a.i./kg body weight did not elicit adverse effect s in m a llard duck or bobwhite quail, indicating that orthosulfam uron TGAI is sl ightly toxic to mallard duck or bobwhite quail on an acute oral basis. Subacute (8-day) diet ary toxicity studies in bobwhite quail (MRID 46219041) and m a llard duck (MRID 46219040) established LC 50 

### values of >4980 mg a.i./kg diet and >4790 mg a.i/kg diet, respectively, indicating thatorthosulfam uron TGAI is slightly toxic to birds on a subacute dietary basis. Study details and results are summ ar ized in Appendix E, Ta ble E-10

. The acute oral LD 50 

### of >1960 m g a .i./kg body weight in bobwhite quail and m a llard duck is used to assess risks of acute oral exposure and the subacute dietary LC 50 

### value of >4790 mg a.i/kg diet is used to assess risks of acute dietary e xposure of birds to orthosulfamuron.
No acute tox i city stud ies were subm itted for bird s exposed to orthosulfam uron form ul ations o r degradates.
Mamm als An acute oral toxicity study of orthosulfam uron i n laboratory rats (Rattu s norvegicus ) indicated that orthosulfam uron is practically non-t oxic to rats (MRID 46219019). The estim ated LD 50 

### is greater than 5000 m g/kg and there were no clinical or sub-lethal signs of toxicity. There were no observed sublethal effects in the orthosulfam uron acute oraltoxicity study on rats.
Terres trial Inverteb rates An acute contact toxicity study in honey bees using orthosulfam uron yi elded a 48-hour contact LD 50 

### >100 μg a.i./bee (MRID 46219046), indicating thatorthosulfam uron is practically nontoxic to honey bees on an acute contact exposure basis. An acute oral toxicity test of orthosulfam uron TGAI in honey bees established an acute oral L D 50 

### >109.4 μg a.i./bee (MRID 46219046). Study details and results are summarized in Appendix E, Table E-12

. No acute co ntact tes t s in honey bees or other te rrestrial invertebrates were subm itted for ortho

sulfam uron form ulations or degradates.

36

### 3.4.2.1.b. Terrestrial Animals: Chronic Effects
Birds Chronic studies of the reproduc tive toxicity of orthosulfam uron in m a llard duck (MRID 46578949) and bobwhite quail (MRID 46578950) adm i ni stered orthosulfam uron TGAI for approxim ately 21 weeks. Study detail s and results are summ ar ized in Appendix E, Ta ble E-11

. Results of both studies showed no treatm e nt-re lated effects on adult bird mortality, food consum ption, body weight, clinical signs, or reproductive endpoi nts at the highest dietary concentration tested (NOAEC = 1280 m g a.i./kg diet). In addition, no clinical signs or treatm ent-related effects in offspring survival or body weight were observed at the highest dietary concentration tested in these studies (1280 m g a.i/kg diet). The NOAEC o f 12 80 m g a.i/kg d i et is used to ass e ss the chronic ri sk of orthosulfam uron in avian species. No chronic toxicity studies of orthosulfam uron form ulations or de grad ates in avian sp ecies were subm itted.
Mamm als A chronic, 2-generation toxici ty study was conducted to eval uate the potential chronic and reproductive effects of orthos ulfam uron on laboratory rats, Rattus norvegicus (MRID 46219033). The m o st sensitiv e endp oints ar e in c r eased incid ence of kidn ey les i ons and decrea se d m o tor activity. For this screen ing-level ecological risk assessm ent, the endpointrelated to decreased motor activity was used because it is likely pr otective for rep r oductive effects. Moreover, decrea sed motor ac tiv ity f o r species in the wild c ould resu lt in a decre ase in ability to avoid predators, acquire food, or obtain territories or mates. Decreased m otor activity was observed in F1 m a les and had an associated NOAEC o f 88.6 m g/kg/day (NOAE L = 1400 pp m )

. Terres trial Inverteb rates No chronic toxicity stud ies were sub m itted f o r orthosulf am uron TGAI, f o rm ulations, or degradates in terrestrial invertebrates.

3.4.2.1.d. Terrestrial Animal s: Field Studies
No f i eld stu d ies were su bm itted f o r chronic ef f ect s of orthos ulf am uron on terr estria l organism s. 3.4.2.2. Terrestrial Plants The effects of the orthosulfam uron form ul ation, IR5878 50WG (TEP; 49.96% a.i.) on m onocots (corn, oat, onion, and rice) and dicots (carrot, m ung bean, oilseed rape, pea, radish, and soybean) were tested in Tier II seedling em erge nce (MRID 46578941) and vegetative vigor (MRID 465789-42) studies. Results of the Tier II seedling em ergence study id entify rice as the m o st sensitive m onocot and radish as the m ost sensitive dicot, with decrea sed dry weight as the m o st sensitive endpoint affected. The NOAE C and EC 25 

### values of 0.015 lbs a.i./A and 0.078 lbs a.i./A, respectively, for

37

## 4 rice, and 0.015 lbs a.i./A and 0.040 lb s a.i./A, respectively, for radish is used to assess the effects of exposure to orthosulfamuron on seedling em ergen ce in non-listed and list ed terrestrial plants. Results of th e Tier II veg etative vigo r studies identif y onion as the m o st sensitiv e m o nocot and carro t as the m ost sensitive dicot, with decrea sed dry weight as the m o st sensitive endpoint affected. The NOAE C and EC 25 

### values of 0.00169 lbs a.i./A and 0.0048 lbs a.i./A, respectively, for onion, and the EC 05 

### and EC 25 

### values 0.000027 lbs a.i./A and 0.00012 lbs a.i./A, respectively, for carrot are used to assess the effects of expos ure to orthosulfam uron on vegetative vigor in non-listed and listed terrestrial plants. The NOAEC for carrot is below the lowest tested concentrations (<0.000066 lb s a.i./A), hence the EC 05 

### is used to estim ate risks to dicotyledonous plants. 

## Risk Characteriz ation Risk characterization is the integration of exposure and effects to estim ate the potential ecological risk from the proposed use of orthosulfam uron on rice. The goal of risk characterization is to p r o v ide an es tim ate and description of potential adverse effects and to articulate r i s k assessm ent assum p tions, lim itation s, and uncertainties in o r der to synth esize an overall risk conclusion.
4.1 Risk Estimation – Integratio n of Exposure and Effects Data Toxicity data and exposure estim ates are used to evaluate the potential for adverse ecological effects on non-target species. Fo r this screening-level assess m e nt of orthosulfam uron, the determ inistic risk quotient m e thod is used to prov ide a m e tric of potential risks. The RQ is a com p arison of exposure estim ates to toxicity en dpoints; estim ated expos ure concentrations are divided by acute and chronic toxicity values. The resulting un itless RQs are com pared to the Agency’s LOCs, which are th e Agency’s interp retive po licy s u ch that when LOCs are exceeded, the need for regulatory action should be considere d. These criteria are used to indicate when the use of a pesticide, as directed on the label, has the potential to cause adverse effects on nontarget organism s. 4.1.1 Non-target Aquatic Organisms The surface water EEC (peak and chronic valu e) from the Interim Rice Model was compared to acute and chronic toxicity endpoi nts to derive acute and chro nic RQs for non-target aquatic organism s. Acute and chronic RQs for fresh- and saltwater organism s are summarized in Tables 4.1 and 4.2 , respec tive l y. For aquatic vascular and non- vascular plants, peak EECs are com pared to acute EC 50 

### values to derive acute non-listed species RQ s. In addition, peak EECs ar e also com p ared to NOAEC or EC 05 

### values for aquatic plants to derive listed species RQs. All RQs for aquatic p l ants are presented in Table 4.3.
4.1.1.1 Freshwater Fish and Invertebrates

38

### The RQs did not exceed non-listed o r listed species acute or chronic risk LOCs for freshwater fish, aquatic-phase am phibians, or freshwater inv e rtebrates. Table 4.1 lists the RQs for freshwater fish, aquatic-p hase am phibians, and f r e shwater inv e rtebr ate s potentia lly exp o sed to orthosulfam uron associated withthe proposed use on rice.
Table 4.1. Risk Quotients for Freshw ater Fish and Invertebrates Exposed to Orthosulfa muron for Use on Rice.

Use A nnu al App licatio n Rate EECs ( ppb ) Fi sh an d Am phi bi anR Q s LC 50 = 12 200 0 N OA E C = 6100 Inverte b rate R Q s LC 50 = 97 300 N OA E C = 6500 Peak Acute C hr oni c Acute C hr oni c R i ce 0. 06 9 lb s a .i ./A 38 .6 <0. 01 <0. 01 <0. 0 1 <0.01 

### 4.1.1.2 Estuarine/Marin e Fish and Invertebrates The RQs did not exceed non-listed o r listed sp ecies acute or chronic risk LOCs for estuarine/m arine fish or invertebrates. Table 4.2 lists the RQs f o r estuar in e/m arine f i sh and invertebrates potentially exposed to orthosulfam uron associated w ith the proposed use on rice.
Table 4.2. Risk Quotients for Estu arine/ Marine Fish and Invertebrates Exposed to Orthosu l famuron.

Use Application Rate lbs ai /A (1 application) 

### EECs (ppb) Fish RQs

LC 50 = 123000 p p b

NOAEC = N/A 

### Invertebrate RQs

LC 50 = 122000 p p b NOAEC = 27000 ppb Mollusk RQs
EC 50 = 97000 ppb
P eak Acute Acute Chronic Acute


### Rice 0.06 9 38 .6 <0. 01 <0. 0 1 <0.01 <0. 01



### 4.1.1.3 Aquatic Plan ts The non-listed species acute risk LOC is exceeded for aquatic vascular plants (RQ = 55). For listed species, the acute risk LO C of 1.0 is exceeded for aquatic vascular plants and saltwater non-vascular plants with RQs of 148 and 1.8, respectively. The risk profile for aquatic plants seem s to be driven by the higher toxicity of orthosulfam uron to vascular plants. Table 4.3 lists the RQs for aquatic vascular and non-vascular plants potentially exposed to orthosulfamuron.

Table 4.3. Risk Quotients for Fresh- and Saltw ater Plants Exposed to Orthosulfa muron for Use on Rice.

Use Total Seasonal Application Rate lbs ai /A 

### EECs (ppb) Freshwater Vascular Pl ant RQs

EC 50 = 0. 7 ppb NOAEC = 0.26 ppb 

### Freshwater Non-Vascular

Plant RQs

EC 50 = 800 ppb NOAEC = 280 ppb 

### Saltwater Non-Vascular

Plant RQs

EC 50 = 80 ppb NOAEC = 21 ppb



### 39P eak Acute Acute Listed S p ecies Acute Acute Listed S p ecies Acute Acute Listed S p ecies 

### Rice 0.06 9 38 .6 55 * 14 8 * 0. 05 0. 14 0. 48 1. 84 *
*Exce e ds aqu ati c pl ant acute ris k LOC (RQ > 1

. 0 ) ; app lies to non- listed and listed species 

### 4.1.2 Non-target Terrestrial Organisms The EEC values for estim ated exposure to terr estrial anim als for spray applications of orthosulfam uron were derived usin g the Kenaga nom ogram , as m odi fied by Fletcher (Fletcher et al., 1994). Exposure estim ates were generated fo r the proposed label use of orthosulfam uron on rice with a single application of the water dispersible granule form ulation of 0.069 lbs a.i./A. The application rate represents the maxim um as s pecified by the proposed label. Risk quotients for the dry granule form ulation of ort hosulfam uron were estim ated using the LD 50 

### /f t 2 

### m e thod with an application rate of 0.067 lbs a.i./A. The RQs are based on these m axi m um e xposure estim ates and the lowest available toxicity endpoints for a gi ven taxa and exposure duration ( e.g. acute av ian). Specifically for this ass e ssm ent, the lowest LD 50 

### and NOAE C values were used for birds and m ammals. Note again that data from avian toxicity studies were used to represent reptiles and terrestrial-phase am phibians. Acute and chronic RQs for birds, reptiles, and terrestrial-phase am phibians are presented in Tables 4.4 and 4.5 , respectively, acute and chron i c RQs for mammals are summarized in Tables 4.6 , 4.7 , and 4.8 , respectively.
4.1.2.1 Birds No RQs exc eed non-listed or listed species acute risk LOCs with RQs < 0.01. Table 4.4 lists the avian dose-based acute RQs for proposed use of the dry granule and water dispersible granule form ulation of orthosulfam uron on r i ce. Fo r the dry granule form ulation, since an LD 50 

### was not generated, it is difficult to estim ate the am ount of gr anules that need to be consum ed to elicit a toxicological response. However, assum i ng that e ffects occur at the highes t tested concentration of 1960 m g/kg bw for the m a llard duck, a 1.0 kg bird would have to consum e about 0.007 lbs of orthosulfam uron, which is equivale nt to about %10 of the number of granules applied on a given acre. Becau se it is likelythat a 1.0 k g bird would have to con sum e significantly m o re than th is due to low orthosulfam uron toxic ity and that dry granule consum ption would be restricted to em bankm e nts and paddy divisions, adverse effect s to birds associated with consum ption of granules is low.
Table 4.4. A v ian Dose-Based Acute RQ Values f o r Orthosulf a muron Use on Rice; Bas e d on Bobwhite Quail LD 50

### >1960 mg/kg b wand Upper-Bound Kenaga Residues.

Use Application Rate lbs ai/A Bod y Weight

(g) RQs for Granular Avian Acute R Q s fo r S p ecifie dF o od Item s Short Grass Ta ll Gra ss Broadleaf Plants/Sm a ll Ins ects Fruits/Pods/ S eeds / Large Insects
Rice 0. 06 9 20 <0. 01 <0. 01 <0. 01 <0. 01 <0. 01 10 0 <0. 01 <0. 01 <0. 01 <0. 01 <0. 01



### 4010 0 0 <0. 01 <0. 01 <0. 01 <0. 01 <0. 01
Acute Ri sk LOC s ; non-listed species RQ> 0

. 5 and list e d spe c ies R Q > 0.1 

### No acute or chronic LO Cs are exceeded. Acute and chronic diet ary-based RQs are < 0.01. Table 4.5 lists the acute and chronic di etary-based avian RQs for proposed use of orthosulfam uron. Table 4.5. Acute and Chronic Dietary-BasedRQ Values for Birds Exposed to Orthosulfamuron Based on Uppe r-Bound Kenaga Values. Use Application R ate lbs ai/A 1 application Food Item s EEC (m g/kg) Acute Dietary RQ C hr oni c Dietary RQ
Rice 0. 06 9 Short Gr ass 16.56 <0.01 0.01 Tall G r ass 7.59 <0.01 0.01 Broadleaf plants / s m all insects 9.32 <0.01 0.01 Fr

uits, pods, seeds, lar g e insects 1.04 <0.01 <0.01
Acute Ri sk LOC s ; non-listed species RQ> 0

. 5 and list e d spe c ies R Q > 0.1 Chronic Ri sk LOC; RQ>1.0 fo r non-listed and listed species 

### 4.1.2.2 Mammals No acute risk LOCs are exceeded with RQs ranging from <0.01 to 0.01. Table 4.6 lists the dose-based acute m amm alian RQs for proposes use of both the dry granule and water dispersible granule formulations of orthosulfam uron. Table 4.6. Mammalian Dose-Based Acute R Q V a lues for Use s of Orthosul famuron; Based on Rat LD 50 

### >5000mg/kg bw and Upper-Bound Kenaga Residues.

Use Applicat i on Rate lbs ai/A Bod y Weight

(g) RQs for Granular M amm al i an A c ut e R Qs f o r Specified Food Ite m s Short Gra ss Ta ll Gra ss Broadleaf Plants/Sm a ll Ins ects Fruits/Pods/ Lg Inse cts S eeds

Rice 0. 06 9 15 <0. 01 <0. 01 <0. 01 <0. 01 <0. 01 <0. 01 35 <0. 01 <0. 01 <0. 01 <0. 01 <0. 01 <0. 01 10 0 0 <0. 01 <0. 01 <0. 01 <0. 01 <0. 01 <0. 01
Acute Ri sk LOC s ; non-listed species RQ> 0

. 5 and list e d spe c ies R Q > 0.1 

### The non-listed and listed species chronic risk LOC (RQ>1.0) is not exceeded for the proposed use of orthosulfam uron on rice for m ammals (RQs range from <0.01-0.08). Table 4.7 lists the dose-based chronic m ammalian RQs for pr oposed uses of orthosulfam uron. Table 4.7. Mammalian Dose-Based Chronic RQ Values for U ses of Orthos ulfamuron; Based on Rat NOAEL of 88.6 mg/kg b wand Upper-Bound Kenaga Residues.

Use Application Rate lbs ai/A Bod y Weight

(g) M amm al i an A c ut e R Qs f o r Specified Food Ite m s Short Grass Ta ll Gra ss Broadleaf Plants/Sm a ll Ins ects Fruits/Pods/ Lg Inse cts S eeds

Rice 0. 06 9 15 0. 08 0. 04 0. 05 0. 01 <0. 01 35 0. 07 0. 03 0. 04 <0. 01 <0. 01



### 4110 0 0 0. 04 0. 02 0. 02 <0. 01 <0. 01
Boldedvalu es e x ceed th e chroni c ris k LOC (RQ > 1.0) for non-listed and listed mammalian species 

### The RQs do not exceed the chronic risk LOCs fo rany proposed uses of orthosulfam uron with RQs < 0.01. Table 4.8 lists chronic dietary-based m amm alian RQs for proposed uses of orthosulfam uron. These RQs are based on effects le vels associated with chem ical concentrations in feed.
Table 4.8. Chronic Dietary-BasedRQ Values for Mammals Exposed to Orthosulfamuron Based on Uppe r-Bound Kenaga Values. Use Application R ate lbs ai/A Food Item s EEC (m g/kg) Chronic Dietary RQ

Rice 0. 06 9 Short Gr ass 16.56 0.01 Tall G r ass 7.59 <0.01 Broadleaf plants / s m all insects 9.32 0. 01 Fr

uits, pods, seeds, lar g e insects 1.04 <0.01
The chronic risk LOC for non- listed an d listed mammalian species is RQ> 1. 0 

### 4.1.2.3 Terrestrial Plants Table 4.9 lists the terrestrial and sem i -aquatic plant RQs for proposed uses of orthosulfam uron based on results from Te rrPlant v. 1.2.1 and the Inte rim Rice Model. The analysis indicates that for dicotyledonous plants adjacent to orthosulfamuron treated paddies, th e RQ exceeds the acut e risk LOC (RQ > 1.0) as a result of drift. Alternatively, RQs based on tail water release for sem i

aquatic plants did not ex ceed the non -listed sp eci es acute risk LOC for either m onocotyledonous or dicotyledonous plants although th e RQ for sem i -aquatic dicots is very close to the LOC (RQ = 0.92). The difference in risk estim ates for the tw o s cenarios is in part due to the fact that results from the vegetative vigor study are used for ri sk estim ates associated with drift; the other scenario incorporates to xicity values from the seedling em ergence tests. For lis ted sp ecies, RQs exceeded th e listed species acute risk LOC for sem i -aquatic monocots an d dicots. In addition, RQs exceeded the listed species acute risk LOC associated w ith spray drift for both monocots (aerial applications only) and dicots (ground and aerial spray). Although EECs were based on the application rate for the water dispersible gr anule form ul ation, results for sem i -aquatic plant species can be applied to th e dry granule form ul ation of orthosulfam uron as well since applic ation r ates f o r th e two f o rm ul ations are very sim ilar.
Table 4.9. R Q Values forTerr estrial and Semi-Aquatic Plant s Exposed to Orthosulfamuron Based on Proposed Use on Rice of 0.0 69 lbs a . i./A.

Plant ToxicityMeasure m e nt Endpoi nt RQs Ba sed on Tier II Seedling Em ergen ce and Vegetative Vi gor Studies Semi-Aqu atic Drift
Tail wa ter release Gr ound spray Aerial spray 

### Non-Listed Plant Species ( B ased on EC 25 

### )



### 42

### Monocot 0.078 lbs ai./A S eed Emerg 0.0048 lbs ai/A Veg Vig 

### 0.47 0.14 0.72 

### Dicot 0.04 lbs ai/A Seed Emerg 0.00012 lbs ai/A Veg Vig 

### 0.92 5.75 28.8 Listed Plant Species (B ase d on NOAEC or EC 05 

### ) 

### Monocot 0.015 lbs ai/A Seed Emerg 0.00169 lbs ai/A Veg Vig 

### 2.45 0.41 2.04 

### Dicot 0.015 lbs ai/A Seed Emerg 0.000027 lbs ai/A Veg Vig 

### 2.45 25.5 6 127. 78 Bolded value s exceed non-listed or listed plant acute risk LOC (RQ > 1.0). 

### 4.2 Risk Description The available data on the fate and effects of ortho sulfam uron are sufficient to add r ess the risk hypothesis f or all taxa, as specified in the Overview Docum e nt (USEPA, 2004). The results of this screening-level risk assessm ent indicate some com ponents of the risk hypothesis are accepted; th ere is po tent ial for direct adverse acute effects for freshwat er non-vascular plants, estuarine/m arine non-vascular plants, and terrestrial and sem i -aquati c plants, particularly dicots. These results are based on m odeled spray applic ation rates of 0.069 lbs a.i./A per year, which represents the proposed use of orthosulfam uron applied at the m a xim um l abel rate and is likely sim ilar to the slightly lower rate of 0.066 lbs a.i./A per year associated with the dry granule form ulation.
4.2.1 Risk to Aquatic Organisms Aquatic EE Cs were based on the Interim Rice Mode l and represent peak or chronic values of orthosulfam uron that m ay be present in rice paddy tail water. The result s of the screening-level analys is ind i cate that the potential of orthosulfam uron to adversely affect aquatic anim als is low. Risk quotients for fresh- and sa ltwater fish and invertebrates are all below 0.01; no acute or chronic risk LOCs are exceeded. Ho wever, ortho s ulfam uron has the po tential to adversely affect aquatic vascular plant species since the RQ for non-listed vascular plants is 55. Alternatively, orthosulfam uron is less toxic to non-vascular plants; RQs for non-listed non-vascular plants ranged from 0.05 to 0.48 and as such are below the acute risk LOC.
4.2.1.1 Freshwater Fish Acute and chronic RQs for freshwater fish are below acute and chronic risk LOCs, indicating that a po tential for direct effects to freshwater fi sh is low for the use of orthosulfam uron on rice. The freshwater fish toxicity data indicate that orthosulfam uron and degradates are slightly to practically non-toxic to tested species, which partly explains why RQ val ues were below the LOCs. Extrapolation to other f r eshw ater f i sh is un certain. In all like lihoo d, m o re sens itiv e species exist but given the low pot ential for adverse effect to tested species, the potential for adverse effects on freshw ater fish or aquati c-phase am phibians is believed to be low.
4.2.1.2 Freshwater Invertebrates

43

### Acute and chronic RQs for freshwater inverteb rates are belo w acute and chronic risk LOCs, indicating a low potential for dire ct adverse effects to freshwater invertebrates for the use of orthosulfam uron on rice. The freshwater invertebrates’ toxici ty data ind i cate thatortho sulf am uron is slightly to practica lly non-toxic to tested species, which partly expl ains why RQ val ues were below the LOCs. Extrapolatio n to other freshwater inv erteb rates is uncertain. In all likeliho od, m o re sensitiv e species exist but given the low pot ential for adverse effects based on tes t ed species, th e potential for adverse effects on other freshwater i nvertebrates is expected to be low

. 4.2.1.3 Saltwater Fish The potential for advers e effects including acute mort ality for estuarine/marine fish is low, based on the resu lts of the scre ening asse ss m ent; acute RQs for rice are below the acute risk LOC. No chronic estu arine/m arine fish toxicitydata were s u bm itted for orthosulfam uron, however, given the low potential for acute advers e effects and the low potential for chronic effects in freshwater fish species, the potential for chronic effects in sa ltwater fish species is presum ed to be low.
4.2.1.4 Saltwater Invertebrates Acute and chronic RQs for estuarine/m arine inve rtebrates are below acute risk LOCs, indicating that a potential for direct advers e effects to s a ltwater invertebrate s is low for the proposed use of orthosulfam uron on rice. The saltwater invertebrate toxicity data indicate that orthosulf am uron is slightly to practically non-toxic to tested species, which partly expl ains why RQ val ues were below the LOCs. Extrapolatio n to othe r sa ltwate r inve rt ebrates is un certain. In all like lihoo d, m o re sens itiv e species exis t but given th e low potential for effect s to tes t ed s p ecies, the p o tential f o r a dverse effects on saltwater invertebrate s is e xpected to b e low.
4.2.1.5Aquatic Plan ts Based on predicted EECs for the m o deled orthosulfam uron use and available toxicity data, LOCs are exceeded for non-listed, vascular aquatic plants by a factor of 55X. The relatively high RQs for these species are largely due to the very high acute toxicity of orthos ulfam uron to vascular plant species. In contrast, non-vascular plant ac ute risk LOCs are not exceeded for the use of orthosulfam uron on rice; RQs are 0.05-0.48. Aquatic plants are k e y com ponents to all aq u atic ecosystem s and provide a m u ltitude of ecological f unctions. T hey provide food and shelte r for a wide variety of aquatic anim al species and help m a intain water quality through tem p er ature m odulation, filtration, and oxygen supply. Any effects on aquatic p l ants as a res ult of orthosulfam uron use could result in significant ecosystem -level effects. Most notab ly, there wo u l d lik ely be a near instant decrease in water quality associated with plant de cay and depletion of oxygen. In turn, sedim e ntation would likely increase due to decay an d a loss in filtering cap acity. The depletion of oxygen and increased

44

### siltation cou l d resu lt in widespread fish and invertebrate m o rtality. The cascade of effects due to effects on aquatic plants would pos e a risk to anyaquatic species near th e use area as well as terrestrial species that rely on aquatic organism s as food item s such as piscivorous birds, m ammals, or reptiles.
4.2.2 Risks to Terrestrial Organisms
4.2.2.1 Birds No avian acute or chronic risk LOCs are exceed ed for any uses of orthosulfam uron i ndicating that the potential for adv e rse effects on birds is low. Toxicity studi es on orthosulfam uron indicated technical grade orthos ulfam uron is practically non-toxi c to birds on an acute oral exposure basis. For the subacute dietary study, orthosulfam uron is classified as slightly toxic with an LC 50 

### of 4790 mg/kg feed. Results from the chronic study yielded a NOAE C for bobwhite quail exposed to orthosulfamuron of 1280 m g/kg feed, which was the highest exposure level tested. Taken as a whole, the risk estim atio n results and the tox i city data ind i cate a low potential for direct adverse e ffects to avian species associat ed with the proposed use of orthosulfam uron. However, given the potential f or effects on terr estrial and aquati c plant species associated w ith the use of orthosulfamuron, indir ect effects on birds are possible. S i nce plants com p rise vital com ponents of all habitats and ecosystem s, if alterati ons in the abundance of plants or in the com position of habitats (plant community) were to o ccur as a resu lt of orthosulfam uron use, then it is likely that at leas t som e bird species would be affected. Indirect effects could range fro ma decreas e or change in forage base or on the availability of suitable nesting habitats.
4.2.2.2 Mammals Acute risk s to wild m amm als were ev aluated using a common laboratory rat LD 50 

### values, which exceeds the highest tested concentration (>5000 mg /kg bw). Orthosulfamuron is practically nontoxic to m ammals on an acute exposure basis. Ca lculated dose-based RQ s for all proposed uses of orthosulfam uron on r i ce are below the acute risk LOC. The low appare nt acute toxicity of orthosulfam uron and the calculate d RQs indicate a low potential fo r direct adverse ef fects to m ammals associated with the use of orthosulfam uron on rice. Sim ilarly, an evaluation of chronic risks showed that the do se-based chronic risk LOCs are not exceeded for the proposed use of orthosulfam uron on rice. Taken as a whole, the toxicity data and th e r i sk estim ates in dicate that the potential for adverse effects to mammals asso ciated with the use of orthosulfam uron on rice is low. However, sim ilar to the po tentia l f o r indi rect effects to birds, th e use of orthosulfam uron could indirectly affect mammals by altering critic al habitat components. An alteration in the abundance o r com positio n of plant sp ecies in a gi ven habitat could resu lt in an inability to acquire necessary energy for surviv al or alter the use of the habitat in such a way as to disrupt norm a l behaviors (like mating).
4.2.2.3 Potential Risk to Bird s and Mammals: BCF Analysis

45

### A fish bioconcentration study was su bm itte d for orthosulfam uron indicating that bioconcentration of orthosulfam uron is unlikely; the highest estim ated BCF is 1.14. Risk quotients for birds were calculated by com paring estim ated orthosulfam uron concentrations in fish to the dietary-based NOAE C. For m ammals , RQs were calculated using estim ates of food ingestion rate (USEPA, 1993; Appendix D ) and com paring a daily dose to dose-based NOAE L. Orthosulfamuron in fish was assum e d to be 1.14 tim es the highest aquatic EEC, which was 46.17 ppb (0.046 ppm ) representing a m aximum EEC for ri ce. This exercise indicates that the potential adverse chronic effects to avian and m ammalian piscivorous spec ies, is lim ited since chronic RQs are <0.01 for both m amm als and birds. Since the acute toxicity values w e re significantly higher than chronic en dpoints, there is also a very lim ited potentia l f o r ac ute r i sks. Hence this an alysis indic ates that risk s to pi scivorous birds and m amm al s associated w ith th e proposed use of orthosulfa m uron on rice are unlikely.
4.2.2.4 Plants Tier II plant studies demonstrate the potential for orthosulfam uron to affect terres trial d i cot and monocot plants. Exposure levels equivalent to a 25% effect level we re 0.0048 lbs a.i./A for monocots and 0.000012 lbs a.i./A for dicots for the vegetative vi gor study. Results from the seedling emergence test indicate d that a 25% effect level was 0.015 lbs a.i./a for both m onocots and dicots. Risk quotients for terrestrial plants ranged from 0.14 to 28.8 and for sem i

- a quatic plants RQs ranged from 0.47-0.92. Taken as a whole, the toxicity studies and the R Q s indicate a potential for adverse effect s to terrestrial dicots as a result of exposures to orthosulfam uron. Risk quotient s for both m onoc ots and dicots exceeded the listed species acute risk LOC for sem i

aquatic plants and for the drift scenario (RQs ranged from 2.5-128) except for ground spray to terrestrial monocots. As with any toxicity test, there are un certainti es regarding wh ether tes tsp ecies adequately represent the range of po ssible sensitivitie s in th e wild. Plants tested are crop plants, typically subjected to hundreds of years of hum an selection. It is likely th at som e native species are m o re sensitive than commonly used agricultural te st species given the trem endous variation and num b er of wild plant species. Tests using a broader range of species m ay help reduce this uncertainty, but a critical review paper McKelvey et al. (2002) suggests that, in general, crop testing m ay be sufficiently prot ective of m ost plants. Furthe r supporting this contention is a review paper by Clark et al. (2004) which indicated that the current agricultural species used for testing ar e at leas t as sen sitiv e as non -crop spe cie s in 95% of cases ev aluated. Im portantly, however, th ese autho r s also pointo ut that there is no one species or endpoint that is consistently the m o st sensitiv e for all species and that num erous factors can confound com p arison o f test results. Moreover, neither study was a com prehensiv e reviewof the relative sensitivity of all (or even m o st) plants so co nsiderab le un certaintystill rem ains concerning th e adequacy of test species in representing n on-tes tspecies. In the su bm itted tox i city tests for orthosulfam uron, 10 species (4 monocots, 6 dicots) are used to repr esent all plant species. For orthosulfam uron, the EC 25 

### for 3 of the 6 dicot species was low enough thatRQs based on these toxicity values exceed the acute risk LOC.

46

### There are several un certainties regarding the us e of TerrPlant to assess risk to plants. One is whether the default assumption of 5% spray dr if t (f rom aeria l application ) is suf f i ciently protective. Estim ates made from actual drift assessm ents range to higher than 20% for fine sprays, which could indicate that ri sk to plants is underestim ated. To gain a better understanding of the potential for spray drift to affe c tte rres trial p l ants, T i er I AgDRIFT ® 

### modeling (v. 2.01) was used to determ ine how far off-field orthosulf am uron levels would rem a in above the EC 25 

### for vegetative vigor of dicotyledonous plants (0.00012 lbs a.i./A). AgDRIFT ® 

### utilizes e mpirica l data to estimate off-site depos ition of aerial and ground applied pe sticides, and acts as a tool for evaluating the potential of buffer zones to protect sensitive hab itats from undesired exposures. Assum i ng the m axi m um single appl ication rate of 0.069 lbs a.i./A , fine to m edium droplet size,10 m ph winds, and 10 ft application height, plants 550 ft or closer to the treated use area m ay be exposed to levels of orthosulfam uron above the EC 25 

### . If droplet size is increased to m e dium -course, plants closer than 275 feet m ay be exposed to levels of orthosulfam uron above the EC 25 

### , while the use of course to very course droplet size would result in plants closer than 180 feet potentially being e xposed to orthosulfamuron at levels above the EC 25 

### . Alter n ative l y, if droplet size were reduced to ve ry fine to fine, the distance from the treated paddy where spray drift m i ght exceed the E C 25 

### extends beyond the range that AgDRIFT ® 

### calculates (>997 ft). Clearly, d r o p let s i ze has a significantim pact on the ex tentof spray dr if t. For lis ted plant spec ies, all estim ated distan ces would be even greater. A num ber of factors othe r than droplet size can significantly im pact spray drift including wi nd speed, height above ground, nozzle size and angle, boom width, etc

. AgDRIFT ® 

### allows for higher tier assessm ents although these were not conducted f or orthosulfam uron. M ore details concerning the specifics and uncertainties of AgDRIFT ® 

### are available online at www.agdrift.co m
. Exposure to sem i -aquatic plants is typically es tim ated using TerrPlant, which com bines exposure due to runoff and drift. However, for th is assessm ent, runoff does not apply since orthosulfam uron is applied direc tly to rice paddy water. Exposure estim ates for sem i -aquatic plants were estim ated us ing the Interim Rice Mo de l with no contribution from spray drift since it is unlik ely that ta il wate r release and spray dr if t as a result of pesticide application would occur at the sam e tim e. Uncertainties as sociated wi th th e Inte rim Rice Model are discuss e d elsewhere in this chapter (Section 4.3.2.). Another uncertainty associ ated with estim ating risks to plants is that current assessm e nt m e thods account for only a single applicati on of the chem i cal since it is assum e d that effects to plants would likely m anifest after a sing le application and that toxicol ogical response is less dependent on subsequent exposures. It m ay be difficult to confidently apply this reasoning to all plants under all circum stances and hence rem a ins a source of som e uncertainty, ingeneral. However, for the proposed use of orthosulfam uron, only one application is perm itted; if any future proposed us es require m u ltip le app l ication s, this source of uncertainty co uld play an important role.
4.2.2.5Non-Target Terrestrial Invertebrates EFED currently does not estim ate risk quotients fo r terrestrial non-target insects. However, a label statement is required to pr otect foraging honeybees when the LD 50 

### is < 11 μg/bee. Based

47

### on the acute contact toxic ity study to honeybees, the LD 50 

### for orthosulfam uron is >200 μg/bee. This classifies orthosulfam uron as practicallynon-toxic to honeybees on an acute cont act exposure basis.

4.2.3 Federally Threatened and Endange red (L isted) Species of Concern Section 7 of the Endangered Species Act, 16 U. S.C. Section 1536(a)(2), requires all federal agencie s to consult withthe Nation a l Mar i ne Fis h eries Se rvice (NMFS) f o r m arine and anadrom ous listed species, or the United States F i sh and W ildlif e Services (FW S ) f o r listed wildlife and freshwater organism s, if they are proposing an "action" thatm ay af f ect listed spec ies or their designated habitat. Each federal agency is required under the Act to insure that any action they authorize, fund, or carry out is not likely to jeopardize the c ontinued existence of a listed spec ie s or resu lt in the des truction or adverse m odification of designated critical habitat. To jeopard iz e the contin ued exis tenc e of a liste d species m eans "to engag e in an actio n that reasonably would be expected, dire ctly or indirectly, to reduce appreciably the likelihood of both the survival and recovery of a listed species in the wild by re ducing the reproduction, num bers, or distribution of the sp ecies" (50 C .F.R. § 402.02). To f acilitate com p liance with the req u irem ents of the Endang ered Spec ies Act (subsec tion (a)(2 )), the Office of Pesticide Prog ram s has es tablished procedures to evaluate whether a proposed registration action m ay directly or indir ectly reduce appreciabl y the likelihood of both the survival and recovery of a listed species in the wild by re ducing the reproduction, num bers, or distribution of any listed sp ecies (USEPA, 2004). After the Agency’s screen ing level risk assessm ent is conducted, if any of the Agency’s listed species LOCs ar e exceeded for either direct or indirect effect s, an analysis is conducte d to determ ine if any lis ted or candidate species m ay co-occur in the area of the proposed pest icide use or areas downstream or downwind that could be contam inated from drift or runoff/erosi on. If listed or candidate species m ay be present in the proposed action areas, further biological assessm ent is undert aken. The extent to which listed spec ie s m ay be at risk then d ete rm in es the need for the d evelopm ent of a m o re com prehensive consultation package as required by the Endangered Species Act. The federal action addressed herein is the proposed registration of pesticide products that contain the active ingredient orthosul fam uron. Orthosulfam uron is proposed for use on rice. Rice production areas are predom inantly found in the st ates of California, Mi ssissippi, Arkansas, Louisiana, T e xas, and M i ssouri. However, rice production h a s been docum ented in Illino i s, Florida, Oklahom a and Tennessee although to a lesse r degree (National Agri cultural Statistical Service, 2002).
4.2.3.1 Action Area For listed species assessm e nt pur poses, the actio n area is con sider ed to be the area affected directly or indirectly by orthosulfam uron us e and not m e rely the imm e diate area where orthosulfam uron is applied. At the initial screen ing-level, the risk asse ssm e nt considers broadly described taxonom i c groups and so conservatively assum e s that listed species within those broad

48

### groups are co-located with the pesticide treatm ent area. This m e ans that terrestrial plants and wildlif e ar e assum ed to be located o nor adja cent to th e tr eated site and a quatic o r gan i sm s are assum ed to be located in a surface water body ad jacent to th e treated site. The assessm e nt also assum es that the listed sp ecies are located with in an assum ed area, which has the r elatively highest potential exposure to the pesticide, and that exposures are likely to decrease with distance from the treatment area. Section 1.0 of this risk a ssessm ent presents the proposed pesticide us e sites thatar e used to es tablish in iti al co-location of species with tr eatm ent are as. 4.2.3.2 Taxonomic Groups Potentially at Risk If the assumptions as sociated with th e screeni ng-level action area result in RQs that are below the listed sp ecies LOCs, a "no effect" determ ination conclu sion is m ade with respe ct to lis ted species in that taxa, and no further refinem e nt of the action area is necessary. Furthermore, RQs below the listed species LOCs for a given taxonom ic group indicate no concern for indirect effects on listed species that de pend upon the taxonom i c group for which the RQ was calculated. However, in situations where the screening a ssum ptions lead to RQs in excess of the listed species LO Cs for a given taxonom ic group, a potentia l for a "m ay affect" conclusion exists and m ay be associated with direct effects on listed species belonging to that taxonom ic group or m ay extend to indirect effects upon listed species that depend upon that taxonom ic group as a resource. In such cases, additional inform ation on the biology of listed species, the locations of these species, and the lo cation s of use sites ar e c onsidered to determ ine the extentto which screening assum p tions regarding an action area apply to a particular listed organism

. These subsequent r ef i nem ent steps will con sider how th is inf o rm ation would impact th e action area f o r a particular listed organism and potentially in clude areas of exposure that are downwind and downstream of the pesticide use site.
Assessm ent endpoints, exposure pathways, and the conceptual m odel addressing proposed orthosulfam uron uses, and the associated e xposure and effects analyses conducted for the orthosulfam uron screening-level risk assessm ent are in Sections 2 to 3. The assessm ent endpoints used in the screening- level risk assessm e nt include those defined operationally as reduced survival and reproductive impairm ent for both aquatic and terrestrial anim al species and survival, reproduction, and growth of aquatic and te rrestrial plant species from both direct acute and chronic exposures. These assessm ent endpoi nts address the standard set forth in the Endangered Species Act requiring federal agencies to ensure that any action they auth orize do es not reduce appreciably the likelihoo d of both the survival and recove ry o f a listed spe cies in the wild by reducing the reproduction, numb ers, or distribution of the sp ecies. Risk estim ates, RQs, integrating exposure and effects are calculated for broad based taxa groups for the screeninglevel risk assessm ent are presented in Section 4.1. Both acute endangered species and chronic risk LOCs are considered in the scre ening

- leve l r i sk assessm ent to identify direct and i ndirect effects to taxa of listed species. This section identifies direct effect concerns, by taxa , triggered by exceeding endangered LOCs in the screening level risk assessm ent with an evaluati on of the potential probability of individual effects for exposures that m ay occur at the estab lished endangered species LOC. Da ta on exposure and effects collected un der field con d itions are evaluated to m ake determ inations on the predictive utility of

49

### the direct ef fect sc reen in g assessm ent f i ndings to listed spec ie s. Addition ally, the re s u lts of a screen for in direct effects to listed sp ecies, us i ng direct effect acute and chronic LOCs for each taxonom ic group, is presented and evaluated. A descriptio n of the potential dir ect effects associated with expos ure to o rthosulfam uron for each of the taxonom ic groups is provided below. Table 4.10 provides a summary of the potential direct and indirect effects for federally liste d species, including th e range of RQ value s
.

Table 4.10. Summar y of Direct and Indir ect Effects forFeder a lly Lis t ed Species.

Listed Species Taxonom i c Gr ou p o f C onc ern Direct E ffects RQ Indirect E ffect s Po tential Ass o ciated Taxa 1 Aq uat i c va scul ar pl ant s Acut e: gr o wth 14 8 No No n- vasc ul ar p l ant s No ne 0. 14 No Estuari n e/m arine nonvasc ul ar pl ant s Acut e: cel l den s i ty 1. 84 No Dico t terrestrial p l ants Acut e: p l ant g r o w t h 2

. 4 5 -1 28 No M o n o c o t t e rres tri al pl ant s Acut e: pl ant gr owt h 2. 04

- 2

. 45 No Freshw ater fish Non e Yes Aqu atic & Terrestrial Plan ts Saltwater fish Non e Yes Aqu atic Plan ts Freshw ater inverteb rates Non e Yes Aqu atic & Terrestrial Plan ts Estuari n e/Marine Inverte b rates No ne Yes Aq uatic Plants Mo llu sks Non e Yes Aqu atic Plants Mamm a l s Non e Yes Aqu atic & Terrestrial Plan ts Bird s Non e Yes Aqu atic & Terrestrial Plants Terrest rial inv e rteb rates Non e Yes Aqu atic & Terrestrial Plants 1 Associate dTaxa refe rs to th o se taxa fo r wh ich the r e ar e direct effects t h at may indirectly affect a listed s p ecies tax a
. 

### 4.2.3.2.1 Listed Species Direct Effects Freshwater Fish and Amphibians For the proposed use of orthosulfam uron on rice , acute and chronic LOCs are not exceeded for freshwater fish and aquatic pha se amphibians with all RQs < 0.01. Freshwater Invertebrates For the proposed use of orthosulfam uron on rice , acute and chronic LOCs are not exceeded for freshwater inverteb rates with all RQs < 0.01.

Estuarine/Marine Fish The lis ted sp ecies acute risk LOCs for estuarin e/ m arine fish are not exceeded for any uses of orthosulfam uron when applied at the m axim um l abel rates. Acute RQs for estuar in e m arine fish were all <0.01; chronic RQs were not generate d since there was no life-cycle estuarine/m arine fish toxicity test.

50

### Estuarine/Marine Invertebrates The lis ted sp ecies acute risk LOCs are not exceed ed for m o lluskan and no n-m o lluskan estuar ine /m arine invert eb rates f o r the m odeled use of orthosulfam uron on r i ce (RQ < 0.01). Aquatic Pla n ts The listed sp ecies acute risk LOCs are exceeded f or vascular and saltwat er non-vascular aquatic plants for the use of orthosulfam uronon rice (RQ = 1.84 and 148), calculated as NOAEC or EC 05 

### /EEC). Risk quotients are the highest for aquatic vascular plants prim arily due to the greater sensitivity of vascular plants to orthosulfam ur on; vascular plants were approxim ately 100 and 1000 tim es more sensitive com p ared to salt- an d freshwater non-vascular plants, respectively.
Birds The lis ted sp ecies acute and chr onic risk LOCs forbirds, re ptiles, and terrestrial-phase am phibians are not exceeded for the use of or thosulfam uron on rice a pplied at the m a xim um label rates. Both acute and chronic RQs are <0.01.
Mammals Listed sp ecies acute risk LOCs (RQ > 0.1) for direct effects of orthosulfam uron on m ammals are not exceed ed for the pro posed use of orthosul fam uron on rice; all acute R Q s <0.01. Sim ilarly, listed species chronic risk LOCs (RQ >1.0) are n o t exceed ed for the prop osed use of orthosulfam uron on rice.
Terrestrial Plants Listed sp ecies acute risk LOCs (RQ > 1.0) for direct effects of orthosulfamuron on sem i -aquatic plants are ex ceeded for a single application for th e proposed u se of orthosulfam uron with RQs = 2.45 for both m onocots and dicots. In addition, for terrestrial plants exposed to orthosulfam uron via spray d r ift, the listed species acute risk LOC is exceeded f or dico ts from both ground and aerial spray and for m onocots from a e rial spray o n ly. Listed species acute risk LOCs are not exceeded fo r terres trial plants adjacent to treated areas. 4.2.3.2.2 Probit Dose-R esponse Analysis
Listed Anim al Species P robabili ty of Effects on Individuals The probability of ind i vidual ef f ects at the acute endangered species LO C (RQ = 0.05 which is equivalent to 1/20 of the LC 50 

### or EC 50 

### ) f o r ea ch m ajor listed speci es’ taxonom i c group and the probability of individual effects at estim ated acute RQs above the endang ered species acute risk LOC is provided here. In addition, extrapolati on of low probability ev ents such as those occurring at the LOC, are asso ciated with a high degree of uncertainty. S i nce an an L D 50 

### or LC 50



### 51

### could not be estim ated for any aquatic or terres trial an im al species and sin ce no estim a td RQs exceeded th e LOCs, the probit dose-res ponse an alysis was n ot conducted. Listed Plant Species Probability of E ffects on Individuals For plants, a probit dose-response analysis is not conducted since the Tier II plant tests do not evaluate m o rta lity (LC 50 

### ) and ins t ead m easures th e inhib itory e ffects of a chem ical; th erefore it is dif f i cult to e stim ate the p r obability th at an ind i vid u al will be a f f ected. Uncertainties and Assumptions of th e Probit Dose-Response A nalysis Estim ates of the probability of affecting individu al organism s are based on extrapolation of very low probability events an d are asso ciated withcon siderab le un certainty in the resulting estim ates. T o provide a sense of possible probabili ty valu es, the ana l ysis is also conducted using the lower and upper 95% confidence lim its of the probit dose-response slope, when available. In addition to noting the relatively large uncertainty bounds around the probab ilities, care should be em ployed in inte rpre tingthese prob a b ilitie s beyo nd their intended purpose as an indication of a m argin of sa fety, or lack there of, for the endangered species risk estim ates based on the determ inistic risk quotient m odel. 4.2.3.2.3 Indirect Effects Pesticides have the potential to cause indirect effects to endange red or threatened species by, for exam ple, perturbing forage or prey av ailab i lity, a lte ring th e extent of nesting habitat, etc

. The potential for indirect effects is determined by comparing RQs to the listed and non-listed species LOCs. If the RQ exceeds the listed s pecies LOC th en there is the potential for indirect effects to listed species dependent on those species for wh ich the RQ exceeded th e listed specie s LOC. Sim ilarly, if the RQ exceeds the non-listed species LOC there is the potential for i ndirect effects to lis ted sp ecies that are generally dependent on organism s from the taxa for which RQs exceed the LOC. For aquatic species potentially exposed to orthosulfam uron, RQ s exceeded the listed species acute risk L O Cs to varying degrees f o r aquatic vascular and non-vascular plants and terrestrial and sem i -aquatic plants. Aquatic vascular pl ants had the highest RQs for all uses of orthosulfam uron, ranging from 55-148. Given the sensitiv ities of the aquatic plant taxa to orthosulfam uron, indirect effects to listed species would be expected m ost for species de pendent on fresh- and saltwater vascular and nonvascular plants based on the results of the above analysis. Because aquatic plants are vitally im portant components of any aquatic ecosystem , indirect effects on a number of aquatic (and terr estria l) listed spec ies is possib l e. The m o st obvious indirect eff ects would likely relate directly to reductions in food av ailability o r habitat alterations associated w ith reduced aquatic plant and invertebrate biom ass. Other, less obvious, indirect effects m i ght include disruptions of listed species life cycles if certa in life-cycle components are depe ndent on particular plant or invertebrate species.

52

### For terrestrial species, the screening-level anal ysis indicated that, for the proposed use on rice, orthosulfam uron has the potential to cause deleterious effects inexposed terrestrial and sem i

aquatic plant species (Section 4.1). This suggests potential concern for indirect effects on listed organism s dependant upon these plant species as f ood item s or as im portant habitat com ponents. A potential drop in plant biom ass associated w ith orthosulfam uron use, for exam ple, may significantly alter habitat suitability. While it is likely that plant comm unit i es can be repopulated by imm i grants and living breeders after the use of pe sticid es , if the habitat is altered at a c r itica l life-cycle juncture, over a large area or of if it is altered for long e nough duration, som e species m ay have difficulty surviving. Im portantly, even if the plant biom ass of a particular habitat is not significantly altered in the long-term , changes in plant community structure as a result of dif f erentia l s ensitivity to orthos ulfam uron could result in signif icant eco lo gical changes. The toxicity data for orthosulfam uron indicates thatmonocotyledo nous plants are less sens itiv e than dicotyledonous plants and that th ere is variation in sensitivity within th e tested dico ts ; this variability suggests that plant community structure could be significantly altered in habitats where orthosulfam uron is present. Even if change s in habitat were not pe r m anent, if they were to occur during a sensitive part of the life cycle, su ch as rep r od uction or developm ent, significant indirect effects m i ght be expect ed. A starting point for evaluati ng the potential risk of such scenarios would be to first identify listed species likely to occur in the proposed orthosulfam uron use areas an d their associated life his t ories and determ ine if use is likely to overlap with a sensitive lif e - cycle com p onent. Over lap in this case, would consist of te mporal and spatial cooccurrence of orthosulfam uron use and species. The inform a tion presented on indirect effects serv es as a guide to establish the need f or and extent of ad dition al ana l yses thatm ay be perf or

m ed using Servic es-p rov i ded “spe cie s prof iles” as well as evaluations of the geogr aphical and temporal nature of the exposure to ascertain if a “not likely to adverse l y af f ect” deter m inati on can be m ade. The degree to which addition al analyses are perform ed is commensurate with the predicted probability of adverse effects from the com p arison of the dose-response inform ation with the E E Cs. The greater the probability that exposures w ill p r oduce effects on a taxa, the g r eater the concern for potential indirect effects for listed species dependant upon that taxa, and therefore, the more intensive the analysis on the potential lis ted species o f concern, th eir locati ons relative to the use site, and inform ation regard ing th e use scen ario ( e.g ., tim i ng, frequency, and geogra phical extent of pesticide applic ation )

. 4.2.3.2.4 Listed Species Occurrence Asso ciated with Orthosulfamuron Uses A prelim inary analysis of the co-occurrence of listed plant species and the proposed use of orthosulfam uron was conducted using OPP’s LOCA TES database (Version 2.10). The objective is to provide insight into the pot ential for exposure of lis ted species and to id entify those areas, crop uses, and listed species that warrant further attention. Atabulation of the num berof unique listed plant species in each state associated with proposed uses of orthosulfam uron is provided in Table 4.11

.

53

### By this tabulation there are possi bly a total of 134 listed species fr om all taxa associated with counties where orthosulf am uron m ay potentially be us ed on rice. A total of 8 states have listed species asso ciated with crops on which orthosulfam uron m ay be us ed. California has the highest num b er (72) of listed species that m ay co-occu r with proposed orthosulfam uron use areas. The taxa that has the highest num ber of listed spec ies is dico t plants with a total of 40 unique species for all s t ates for which there is a record of rice cultiv ation. In general, for all proposed uses of orthosulfam uron there is at least one, and usually more, listed species that m ay potentially occur in or neara proposed use area. Appendix H lists the occurrence in each state of counties th at have a listed species of speci fied taxa and th e total list of endangered species that m ay co-occur with proposed uses of orthosulfam uron and a com prehensive list of species in counties where or thosulfam uron m ay be used. This prelim inary analys is ind i cates that th ere is a potential for orthosulfam uron use to overlap with listed species and that a more refined assessm ent is warrante d. The m ore refined assessm e nt should involve clear delineation of the action area associated wi th proposed uses of orthosulfam uron and best available inform ation on the tem poral and spatial co -loc ation of listed sp e cies with res p ect to the action area. This analysis has not been conducted for this assessm ent. Table 4.11. Tabulation by State and Taxonomic Group of Listed Species that Occur in Orthosulfa muron Use Areas for All Proposed Uses. StateAmphibiansArachnidBirdsBivalveConifer/cycadsCrustaceanDicotFerns & alliesFishGastropodInsectLichenMammalMonocotReptilesTotal

Ar

kansas 3 5 3 1 1 13 Califor nia 2 6 3 27 16 5 7 3 3 72 Flor ida 1 8 1 4 1 1 2 1 5 24 I llinois 2 2 1 1 2 9 L ouisiana 6 2 2 2 2 5 19 M i ssissippi 1 5 2 1 2 2 6 19 M i ssour i 2 3 3 3 2 2 15 Oklaho m a 4 2 1 1 2 10 T e nnessee 2 1 1 4 T e xas 1 8 2 1 1 5 18 Total Unique Species 5 23 10 3 40 1 20 7 1 12 4 11 134


### 4.3 Description of Assumptions, Limitations, and Data Gaps
4.3.1 Assumptions and Limitations Re lated to E xposure for All Taxa This screening-level risk assessm ent relies on pr oposed labeled statem ents of the m axi mum rate of orthosulfam uron application for use on rice. The label sp ecifies that orthosulfam uron is only to be applied once per year. The frequency at which actual uses approach these m axim ais dependant on agricultural condi tions (presence of weeds) and m arket forces. Moreover, conditions can change from year to year as weed resistance changes through tim e. It is im portant

54

### to rea liz e th at while a ce rta i n us e pattern m ay prevail at present; th ese patterns can change as a result of changing conditions. 4.3.2 Assumptions and Limitations of Aquatic Exposure Estima tes The Interim Rice Model does not capture degradation processes. This assum ption leads to uncertainty in the m odel’s exposure estim ate co rrelating to the degree to which degradation operates. Factors that affect whether the assum ption of no degr adation rep r esents actu al use scenarios include the length of tim e after application that orthos ulfam uron is held in rice paddy water before release and the environm ental pH, as orthosulfam uron’s majo r route of degradation in acidic to neutral water is hydrolysis, with a ha lf-life of hours to days, and in alkaline water is biodegradation, with a longer half- life of weeks to m onths. Chronic risk estim ates m ay be m o re conservative than acute r i sk estim ates in ac id ic to neutral environm ents as well, due to degradation across the longer exposure period. In summary, the Interim Rice Model calculates screening exposure estim ates th at are not expected to undere stim ate exposure as agronom i c practices and environm ental pH values vary by location. Interim Rice Model exposure estim ate uncertainty corre lates to the degr ee to which m o de l assum ptions do not desc rib e actu al use s ites of orthosulfam uron.

4.3.3 Assumptions and Limitations of Terres t rial Exposure Estima tes 4.3.3.1 Location of plant species
For screen in g-leve l r i sk assessm ents f o r terr estria l plants, all e stim ated exp o sures ar e f o r plants that occur off the treated field. Exposure is therefore a function of the am ount of pesticide that leaves the treated area and enters surrounding habitat via spray drift, release of paddy tail water, or both. However, for this use, it is unlikely th at tail water re lease and runoff would occur at the s ame t i me
. 4.3.3.2 Routes of exposu re Screening-level risk assessm ents fo r spray applications of pesticides consider exposure to plants to occur either through soil m ediat ed pathways or through topical application but not both. This is prim arily due to the fact that submitted toxi city studies do not evaluate com bined exposures. Moreover, the only way this would likely oc cur in the f i eld is if there wer e m u ltiple a pplications and root uptake occurs from left over residues of the f i rs t app lication and topical exposure occurs as a result of subsequent applications. Current ap proaches to assess ing risks to plants, however, do not take into account multiple app lications an d proposed us es for orthos ulfam uron are lim ited to single applications per year as well.
4.3.3.3 Incidental Pesticide Releases Associated with Use This risk assessm ent is based on the assum p tion th at the entir e tre atm ent area is subje ct to orthosulfam uron application at the proposed applicati on rates. In reality, th ere is the potential for uneven application of orthosulfam uron through suchplausible incidents as changes in calibration

55

### of application equipm ent, spillage, an d localized releas es at sp ecifi c areas of the treated field that are asso ciated with specifics of the type of application equipm ent used ( e.g. , increased application at turnabouts when using older ground application equipm e nt). For this a sse ssm ent, the def ault f o liar diss ipation half -lif e of 35 days (W illis and Mc Dowell, 1987) was used to estim ate decline in food-item re sidues as a function of tim e after application. Frequently, studies are availab l e th at allow an es tim ation of the f o liar d i s sipation half -lif e f o r a given chem ical. In this assessm ent, since no terre strial animal RQs exceeded any L O Cs, use of a f o liar dissip ation ha lf -lif e specif i c to orthosulfam uron would not have altered risk conclusions and hence w a s not used. For other uses, however , an orthosulfam uron sp ecific foliar dissipation half-life m ay be im portant in m o re accurately ch aracterizing potential ris k s. 4.3.4 Effects Assessmen t Assu mptions and Limitation
4.3.4.1 Effects of an Adjuvant on Toxicity of Or thosulfamuron to Plants The proposed label for the water dispersible gr anule form ul ation of orthosulfam uron (IR5878 50 WG) states that the u se o f an adjuvantsuch as a nonionic or an organo siliconic surf ac tant is recomm ended. Several studies on the effects of orthosulfam uron on non-vascular plants included exposure to an adjuvant in addition to the water disp ersible granule form ul ation of orthosulfam uron (MRID s 46578934, -35, -36); this repr esents a tank m i xture fo r this herbicide. Results f r o mthese stud ies ind i cated that the adjuvant alone was highl y toxic to non-vascular plants. Although it could not be determ ined from the studies, it is likely that the adjuvant m ay also exacerbate the toxicity of orthosulfam uron. For exam pl e, for the freshwater diatom, Navicula pelliculosa , the EC 50 

### was 0.8 m g a.i./L based on the study that included the adjuvant and was 54 mg a.i./L based on the study on the form ulation alone. For this assessm e nt, the studies that incorporated the adjuvant into th e treatm ents were used for non-vascular plant toxicity endpoints since the addition of the adjuvant repr esents a likely m i xture of orthosulfam uron that will be used for weed control. Although the adjuvant appears to contribute or exacerbate the toxicity of orthosulfam uron to non-vascular plants, there were no sim ilar studies on aquatic vascular plants or terrestrial plants. Given the results observed with the nonvascular plant studies, it seem s likelythat the presence of an adjuvant m ay cause tox i city o r enhance the toxicity of orthosul fam uron to vascu l ar aqu atic p l ants and/or terr estria l plants. Although there is som e uncertainty associated w ith the use of the adjuvant and the potential effects on plants, risk conclusions for this assessm ent would not be altered but it is possible that potential effects as sociated with orth osulfam uron use could, in fact, be hi gher if an adjuvant is used. In addition, given the toxicity of the orthosulfam uron formulati on (w ithout adjuvant) to rice plants, the use of an adjuvant m ay result in adverse effects on rice crops.

4.3.4.2 Age Class and Sensitivity of Effects Thresholds It is generally recognized that test organism age m ay have a significant impact on the observed sensitivity to a toxicant. Although this source of variability is perhaps m o st well docum e nted in anim al species, it m ay apply to plant species as well. However, toxicitystudies are generally

56

### lim ited to yo ung plants o r seedlings lim iting the abili ty to interpret the d i ff erential sens itiv ity of various stages. Further com plicatin g this issue is that som e plants have very com plex life histories that have hardly been characte rized fro ma toxicolo gical p erspective.
4.3.4.3 Lack of Effects Data for Amphibians a n d Reptiles Currently, toxicity stud ies on am phibians and reptiles are not required for pesticide registration. Since these data are lacking, the Agency uses fi sh as surrogates for aquatic phase am phibians and birds as surrogates for terrestrial phase am phibian s and reptiles. These surrogates are thought to be reflective of or protective (m ore sensitive) of herpetofauna. Am phibians are characterized by a perm eable skin. The most im portant route of exposure for aquatic am phibians would likely be the derm al route. Using freshwater fish m ay be s uitable surrogates since exposure would likely be surface area dependentand the g i ll surface of m any fish is a fairly larg e surface area. Also, both fish and am phibians are ectotherm i c so m e tabolic rates and dem ands would likely be sim ilar. For terrestrial s p ecies, how ever, th e difference between am phi bians and birds and reptiles and birds is quite large. Ter r estria l am phibians and re ptiles are both ectotherm ic while birds are endotherm ic; birds have a h i gher bas al m etabolic rate requ ired to m aintain c onstant body tem p erature. The higher m etabolic dem ands of birds may predispose birds to higher relative exposures. However, this does not address any potential differences in toxicity. To date, there are few controlled studies on reptile species that could be used to c o m p are to sim ilar studies on birds. A priori , there is no strong reason suggestin g that one taxon is m ore or less sensitive than another. F urther res ear ch is requ ir e d to dete rm in e whether reptiles and terrestrialphase am phibians are suitably repres ente d by bird species in assessing risks. 4.3.4.4 Use of the Mos t Sensitive Sp ecies Tested Although the screening risk asse ssm e nt relies on a sele cted toxicity endpoint from the most sensitive species tested, it does not necessarily m ean that the sele cted toxicity endpoints reflect sensitivity o f the m o st sensitiv e spec ies exis ting in a given environm ent. The relative position of the m o st sensitiv e spec ie s tested in th e distributio n of all poss i ble sp ecie s is a f unction of the overall variability am ong species to a partic ular chem ical. The relationship between the sensitivity of the m ost tested species versus wild species (including listed species) is unknown and a source of significant uncertainty. The us e of laboratory species has historically been driven by availability and ease of m a intenance. A widespread co m p arison of species is lacking, however, even variation within a species can be qu ite high. Clark et a l

. (2004) conducted a fairly extens ive review of available t oxicity data on non-agricultural plants. T he aim was to com pare these toxic i ty data to tox i citydata from typically used testspecies which are crop sp ecies. Although the authors identified several sources of uncertainty and variabi lity that can com p licate inte rpre tatio nof results, they conc lu ded that p l ants typicallyused f o r tox i city tes ting are atlea st as sensitive as non-crop species in 95% of the cases they evaluated. It is important to consider, however, that the available data set on non-crop species is sm aller than for crop species. Moreover, as m e ntioned previously, the com plex and varied life history of plants, in general, m ay preclude a solid understanding of the relative sens itivitie s of plants us ed f o r toxic i ty tes ting and plants occurring in the wild.

57

### 4.3.4.5Data Gaps Although not a data requirem ent, toxicity data on the m a jor degradates of orthosulfam uron, including the degradate of risk concern o-desm ethyl orthosulfam uron, would reduce som e of the uncertainty in this as sess m ent a ssociated with residues of concern.

58

## 5 Literature Cited Clark, J., Ortega, L.S., and Fairbrother, A. 2004. S ources of variability in plant toxicity testing. Che m osphere 57; pp. 1599-1612. Cohen, S.Z., Creeger, S.M., Carsel, R.F., Enfield, C. G. In “Treatm e nt and Disposal of Pesticide Wastes;” Krueger, R.F., Seiber, J.N., Eds. ; ACS Sym posium Series No. 259, Am erican Che m ical Society: W a s hington, DC, 1984; pp. 297-325. Ecological Comm ittee on FIFRA Risk Assessm ent Methods (ECOFRAM). 1999. ECOFRAM Terrestrial Draft Report. Online at: http ://www.epa.gov/oppefed1/ ecorisk/terrreport.pdf
EFED. 2002. Guidance for Selecting Input Param eters in Modeling the Environm ental Fate and Transport of Pesticides, Version II. U.S. Environm ental Protection Agency, Office of Pesticide Program s, Environm ental Fate and Effects Division, W a shington, DC. Online at: http://www.epa.gov/oppefed1/m o dels/water/index.htm

. Fletcher, J.S ., J.E. Nellessen, and T.G. Pfleeger. 1994. Literature reviewand evaluation of the EPA food-c hain (Kenaga) nom ogram, and instru m e nt for estim ating pesticide residues on plants. Environm ental Toxicology and Che m istry 13 (9):1383-1391. Food and Agriculture Organization of the United Nations. FAO PESTICIDE DISPOSAL SERIES 8. Assessing S o il Contam inatio n: A Reference Manual. Appendix 2. Param e ters of pesticides th at influence processes in th e soil. Editorial Group, FAO Inform ation Division: R o m e , 2000. Online at: http://www.fao.org/DOCREP/003/X2570E/X2 570E00.htm Goring, C.A.I., D.A. Laskowki, J.H. Ham aker, and R.W . Meikle. 1975. Principles of pesticide degradation in soil. P a ges 135-172 in (R. Haque and V.H. Freed, eds.) E nvironm ental Dynam i cs of Pesticides. Plenum Pre ss, New York. Hoerger, F., and E.E. Kenaga. 1972. Pesticide residues on plants: Correlation of representative data as a basis for estim a tion of their m a gnit ude in the environm ent. In F. Coulston and F. Korte, ed s., Environm ental Quality and Saf e ty: Chem istry, Toxicolog y, and Technology, Georg Thiem e Publ, St uttgart, W e st Germ any, pp. 9-28. Kirkwood, J.H. 1983. A lim it to metabolizable en ergy intake in m amma ls and birds. Com p. Biochem . Physiol. 75A :1-3. Mckelvey, R.A., Wr ight, J.P., and Honegger, J.L. 2002. A com parison of crop and non-crop plants as sen sitiv e ind i cator species f o r regul ato r y testing. P est Manag e m ent Science 58; pp. 1161-1174.

59

### National Agricultural Statistic s Service 2002. T able 24. Grains , Corn, Sorghum , Wheat and Other Field Crops: 2002 and 1997. http://www.nass.usda.gov/census/ census02/volum e1/us/st99_2_024_024.pdf
USDA. 2006. 2002 Census of Agriculture: Agricu ltural Atlas of the United States. U.S. Departm e nt of Agriculture, National Agricult ura l Statis tics Se rvice. Onlin e at: http://www.nass.usda.gov/research/atl as02/. Accessed on October 20, 2006.
USEPA. 1993. W ildlife Exposure Factors Handbook. EPA/600/R-13/187a, Office of Research and Developm ent, W a shi ngton, D.C. USEPA 1998. Guidelines for Ecological Risk Assessm ent. EPA/630/R-95/002F.
USEPA. 2002. Policy for Estim ating Aqueous Con centrations from Pe sticides Labeled for Use on Rice. EFED Policy Mem orandum. U.S. Environm ental Protection A g ency, Office of Pesticide Program s, W a shington, D C

. October 29, 2002. 3 pp.
USEPA. 2004. Overview of the Ecological Risk Assessm ent Process in the Office of Pesticide Program s, U.S. Environm ental Protection Ag ency. Office of Prevention, Pesticides and Toxic Substances, Office of Pesticide Pr ogram s, Washington, DC. January 23, 2004.
USEPA. 2006a. W ater Models. U.S. Envir onmental P r otec tion Agency, Pestic ides : Science and Policy. Last updated May 2, 2006. Online at: http://www.epa.gov/oppefed1/m odel s /water/.
W illis, G.H., and L.L. McDowell. 1987. Pesticide Persis ten ce on Foliag e in Review s of Environm ental Contam inati on and T oxicology. 100:23-73. Submitted Studies
MRID 46219009. W oolley, S. and D. Mullee. 2002. IR 5878 (Pure): Determ ination of W ater Solubility. Unpublished study perform e d by Safe pharm Laboratories L i mited, Derby, U.K.; sponsored and sub m itted by ISAGRO S.p. A., Milano, Italy. SPL Project Num b er: 1700/005. Experim e nt initiation July 29, 2002 and com p letion October 3, 2002. Final report issued Nove m ber 12, 2002. 25 pp.
MRID 46219010. Tremain, S. 2002. IR 5878 (Pure) : Determ ination of Vapour Pressure. Unpublished study perform e d by Safe pharm Laboratories L i mited, Derbyshire, U.K.; sponsored and subm itted by ISAGRO S.p.A., Milano, Italy. SPL Project Num b er: 1700/007. Experim e nt initiation August 6, 2002 and com pletion October 24, 2002. Final report issued Decem ber 17, 2002. 19 pp.
MRID 46219011. W oolley, S. and D. Mullee. 2002. IR 5878 (Pure): Determ ination of Dissociation Constant. Unpublished study perform e d by Safe pharm Laboratories

60

### Lim ited, Derby, U.K.; sponsored an d subm itted by ISAGRO S.p.A., Milano, Italy. S P L Project Number: 1700/006. Nove m b er 12, 2002. 7 pp.
MRID 46219012. W oolley, S. and D. Mullee. 2002. IR 5878 (Pure): Determ ination of Partition Coefficient. Unpublished study perf orm e d by Sa fepharm Laboratories L i m ited, Derby, U.K.; sponsored and sub m itted by ISAGRO S.p. A., Milano, Italy. SPL Project Num b er: 1700/023. Experim e nt initiation August 2, 2002 and com pletion August 16, 2002. Final report issued Nove m ber 5, 2002. 25 pp.
MRID 46219017. Scacchi, A. et al. 2003. Aerobi c Aquatic Metabo lism of 14C-IR5878 in Two Am erican Soils. Unpublished study perform e d by ISAGRO RICERCA Srl, Novara, Italy; spons ored and sub m itted by ISAGRO S.p. A., Milano, Italy. Studyand Report No.: MEF.02.14. Experim e nt initiation May 29, 2002 and com pletion Novem b er 11, 2002. Final report issued February 21, 2003. 298 pp.
MRID 46219018. Scacchi, A. and G. Pizzing rilli. 2003. Aged Residue Column Leaching of 14C-IR5878 in an Am erican Soil. Unpublished study perform e d by Isagro Ricerca S r l, Novara, Italy; sponsored and subm itted by Isagro S.p.A., Milano, Italy. S tudy Num b er: MEF.02.17. Experim e nt initiation July 08, 2002 and com pletion Novem b er 04, 2002. Final report issued February 18, 2003. 194 pp.
MRID 46219040. Dias, N.A. 2001. IR5878: Dietary Toxicity (LC 50 

### ) to the Ma llard Duck. Unpublished study perform e d by Hunti ngdon Life Sciences, L t d., Huntingdon, Cam bridgeshire, England. Study No. IGA 005/012373. Study sponsored by ISAGRO S.p.A., Milano, Italy. Study initiated February 2, 2001, com pl e ted May 16, 2001.
MRID 46219041. Rodgers, M. H. and Dias, N. A. 2001. IR5878: Dietary Toxicity (LC 50 

### ) to th e Bobwhite Quail. Unpublished study perf orm e d by Huntingdon Life Sciences, Ltd., Huntingdon, Cam bridgeshire, England. Study No. IGA 002/012368. Study sponsored by ISAGRO S.p.A., Milano, Italy. Study init iated Novem ber 6, 2000, com pl e ted May 17, 2001.
MRID 46219042. Palmer, S.J., M.A. Stence, T.Z. Kendall, and H.O. Krueger. 2002. IR5878: A 96-Hour Static Acute Toxicity Test W ith The Rainbow Trout ( Onchorynchus mykiss ). Unpublished study perform e d by Wildlife Inte rnational, Ltd., East on, MD. Laboratory Project Identificati on No. 544A-107. Study submitted by ISAGRO S.p.A, Centro Uffi ci San Siro, I-20153 Milano Italy. Study in itiated May 23, 2002 and com pl e ted August 19, 2002.
MRID 46219043. Palmer, S.J., T.Z. Kendall, and H.O. Krue ger. 2002. IR5878: A 96-Hour Static Acute Toxicity Test W ith The Bluegill ( Lepomis macrochirus ). Unpublished study perform ed by W ildlife International, Ltd., Easton, MD. Labor atory P r oject Identification No. 544A-111. Study subm itted by ISAGRO S. p.A, Centro Uffici San Siro, I-20153 Milano Italy

. Study initiated Decem ber 18, 2002 and com pleted February5, 2003.

61

### MRID 46219044. Hertl, J. 2000. Final Report: Ac ute toxicity of IR2878 to Daphnia m a gna in a 48-hour immobilization test. Unpub lished s tudy perform e d by Institut für Biologisch e Analytik un d Consultin g IBACON Gm bH , Arheilger W e g, Rossdorf, Germ any. Laboratory Project Identif ication No. 8222220. Study sponsored by ISAGRO S.p.A., 20153 Centro Uffici San Siro - Fabbricato D, Milano, Italy. S tudy initiated May 10, 2000 and completed June 27, 2000.
MRID 46219046. Schmitzer, S. 2001. Laboratory Testing for Toxicity (Acute Contact and Oral LD 50 

### ) of IR5878 on Honey Bees ( Apis Me llifera L. ) Institute for Biological Analysis and Consulting, IBACON Gm bH, Rossdorf, Ge rm any. ISAGRO S.p.A., Centro Uffici San Siro, Milano, Italy. Study Com p letion Date July 10, 2001 (Revised March 3, 2003).
MRID 46219074. Scacchi, A. and G. Pizzing rilli. 2000. Adsorption

- deso rption of 14 C-IR5878 in Soil. Unpublished study perform e d by Is agro Ricerca S r l, Novara, Italy; sponsored and subm itted by Isagro S.p.A., Milano, Italy. S tudy Num ber: ABT.00.04. Experiment initiation February 10, 2000 and completion March 14, 2000. Final report issued April 10, 2000. 129 pp.
MRID 46219015. Castoldi, F. and G. Pizzingrilli. 2000. Hydrolysis of [14C-U-phenyl] IR5878 in Buffered Solutions at pH 4, 7 and 9. Unpublished study perform e d by I S AGRO RICERCA Srl, Novara, Italy; spons ored and sub m itted by IS AGRO S.p.A., Milano, Italy. Study ID: ABT.99.13. Experim e ntal phase (hyd rolysis experim e nt) initiated November 9, 1999 and com pleted on June 14, 2000. Final report issued July 3, 2000. 120 pp.
MRID 46260107. Dias, N.A. 2001. IR5878: Acute oral toxicity (LD 50 

### ) to the Mallard duck. Unpublished study perform e d by Hunti ngdon Life Sciences, L t d., Huntingdon, Cam bridgeshire, England. Study No. IGA 003/012865. Study sponsored by ISAGRO S.p.A., Centro Uffici San Siro - Fabbricato D, Milano, Italy. Study initiated March 14, 2001, com pl e ted March 28, 2001.
MRID 46260108. Dias, N.A. 2001. IR5878: Acute oral toxicity (LD 50 

### ) to the Bobwhite quail. Unpublished study perform e d by Hunti ngdon Life Sciences, L t d., Huntingdon, Cam bridgeshire, England. Study No. IGA 004/012894. Study sponsored by ISAGRO S.p.A., Centro Uffici San Siro - Fabbricato D, Milano, Italy. Study initiated March 30, 2001, com pl e ted April 13, 2001.
MRID 46578931. Desjardins, D., T.Z. Kendall and H.O. Krueger. 2003. IR5878 50 WG Alone: A 96 hour Toxicity Test with the Fres hwater Alga Selenastrum capricornutum. Unpublished study perform e d by Wildlife Inte rnational, Ltd, East on, MD, Project No. 544A-121 and subm itted by ISAGRO S.p.A., Milano, Italy. Final report issued March 25, 2003.
MRID 46578932. Desjardins, D., T.Z. Kendall and H.O. Krueger. 2003. IR5878 50 WG Alone: A 96 hour Toxicity Test wi th the Freshwater Diatom (Navicula pelliculosa ). Unpublished study perform e d by Wildlife Inte rnational, Ltd, East on, MD, Project No.

62

### 544A-119 and subm itted by ISAGRO S.p.A., Milano, Italy. Final report issued March 26, 2003.
MRID 46578933. Desjardins, D., T.Z. Kendall and H.O. Krueger. 2003. IR5878 50 WG Alone: A 96 hour Toxicity Test with the Marine Diatom ( Skeletonema costatum ). Unpublished study perform e d by Wildlife Inte rnational, Ltd, East on, MD, Project No. 544A-122 and subm itted by ISAGRO S.p.A., Milano, Italy. Final report issued April 21, 2003.
MRID 46578934. Desjardins, D., T.Z. Kendall and H.O. Krueger. 2003. IR5878 50WG: A 96 hour Toxicity Test with the Freshwater Al ga Selenastrum capric ornutum

. Unpublished study perform e d by Wildlife International, Ltd, Easton, MD , Project No. 544A-116 and subm itted by ISAGRO S.p.A., Milano, Italy. Final repo rt is sued April 2 1, 2003.
MRID 46578935. Desjardins, D., T.Z. Kendall and H.O. Krueger. 2003. IR5878 50WG: A 96 hour Toxicity Test with the Freshwater Diatom (Navicula pelliculosa ). Unpublished study perform e d by Wildlife International, Ltd, Easton, MD , Project No. 544A-115 and subm itted by ISAGRO S.p.A., Milano, Italy. Final repo rt is sued April 1 1, 2003.
MRID 46578936. Desjardins, D., T.Z. Kendall and H.O. Krueger. 2003. IR5878 50 WG: A 96 hour Toxicity Test withthe Marine Diatom ( Skeletonema costatum)

. Unpublished study perform ed by W ildlife Inte rnational, Ltd, Easton, MD , Project No. 544A-117A and subm itted by ISAGRO S.p.A., Milano, Italy. Final repo rt is sued May 1 5, 2003.
MRID 46578937. Desjardins, D., T.Z. Kendall and H.O. Krueger. 2003. IR5878 50WG: A 96 hour Toxicity Test with the Freshwater Al ga Anabaena flos-aquae. Unpublished study perform ed by W ildlife Inte rnational, Ltd, Easton, MD , Project No. 544A-113 and subm itted by ISAGRO S.p.A., Milano, Italy. Final repo rt is sued June 2 0, 2003.
MRID 46578938. Desjardins, D., T.Z. Kendall and H.O. Krueger. 2003. IR5878 50 WG ALONE: A 96 hour Toxicity Test with the Freshwater Alga Anabaena flos-aquae. Unpublished study perform e d by Wildlife Inte rnational, Ltd, East on, MD, Project No. 544A-118 and subm itted by ISAGRO S.p.A., Milano, Italy. Final report issued June 27, 2003.
MRID 46578939. Desjardins, D., T.Z. Kenda ll and H.O. Krueger. 2003. IR5878 50WG ALONE: A 96 hour Toxicity Test with Duckweed (Lemna gibba ). Unpublished study perform ed by W ildlife Inte rnational, Ltd, Easton, MD , Project No. 544A-120 and subm itted by ISAGRO S.p.A., Milano, Italy. Fi nal repo rt is sued Septem ber 22, 2003

. MRID 46578940. Desjardins, D., T.Z. Kendall and H.O. Krueger. 2003. IR5878 50WG: A 96 hour Toxicity Test with Duckweed ( Lemna gibba ). Unpublished study perform e d by W ildlife International, L t d, Easton, MD , Project No. 544A-114 and submitted by ISAGRO S.p.A., Milano, Italy. Fi nal report issued July 6, 2003.

63

### MRID 46578941. Porch, John R., K. H. Martin and H. O. Krueger. 2003. IR5878 50WG: A Toxicity Te s tto Dete rm ine the Ef f ects on S eedling Em ergence of Ten Species of Plants. Perform ed by W ildlife Inte rnational, Ltd., Easton, MD

. Laboratory study num b er 544-110. Sponsored by ISAGRO S.p.A., Milano , Italy. Study com pleted on October 27, 2003.
MRID 46578942. Porch, John R. and H. O. Krueger. 2003. IR5878 50WG: A Toxi city Test to Determ ine the Effects on Vegetative Vigor of Ten Species of Plants. Perf orm e d by W ildlife International, L t d., Easton, MD. Laboratory study num b er 544-111. Sponsored by ISAGRO S.p.A., Milano, Italy. S tudy com pleted on December 23, 2003.
MRID 46578949. Frey, L.T., et al. 2003. IR5878: A Reproduction Study with the Mallard. Unpublished study perform e d by Wildlife Inte rnational Ltd., Easton, MD. Laboratory Project No. 544-109. Study subm itted by Isagro S.p.A., Milano, Italy. S tudy initiated July 24, 2002 and subm i tted May 29, 2003.
MRID 46578950. Frey, L.T., et al. 2003. IR5878: A Reproduction Study with the N orthern Bobwhite. Unpublished study perform e d by Wildlife Internationa l Ltd., Easton, MD. Laborato ry Project No. 544-108. Study subm itte d by Isagro S.p.A., Milano, Italy. S tudy initiated July 24, 2002 and subm itted May 29, 2003.
MRID 46578951. Palmer, S., Kendall, T., and Krue ger, H. 2002. IR5878: A96-Hour Static Acute Toxicity Test with the Sheepsh ead Minnow

. Unpublished study perform ed by W ildlife International, L t d., Easton Mary land. Laboratory Report Number: 544A-109. Study subm i tted by ISAGRO S.p.A. , Milano, Italy. Experim ental start date was June 24, 2002 and experim e ntal term ination date was June 28, 2002. The final report was issued July 31, 2002.
MRID 46578952. Palmer, S., Kendall, T., and Krue ger, H. 2002. IR5878: A 96-Hour Static Acute Toxicity Test with the Saltwater Mysid ( A m ericamysis bahia ). Unpublished study perform ed by W ildlife Intern ational, Ltd, Easton, Maryland. Laboratory Report Number 544A-108. Study subm i tted by ISAGRO S.p.A. , Milano, Italy. Study Com p letion D ate: August 12, 2002.
MRID 46578953. Palmer, S.J., T.Z. Kendall, and H.O. Krue ger. 2003. IR5878: An Early LifeStage Toxicity Test with the Fathead Minnow ( Pimephales promelas ). Unpublished study perform e d by Wildlife Inte rnational., Ltd., Easton, MD

. Laboratory Project No. 544A-110. Study subm i tted by Isagro S.p.A ., Milano, Italy. Study initiated May 23, 2002 and subm itted Jan u ary 15, 200 3.
MRID 46578954. Blankinship, A.S., T.Z. Znedall, and H.O. Krueger. 2003. IR5878: A FlowThrough Life-Cycle Toxicity Test with the Saltw ater Mysid ( Mysidopsis bahia ). Com p leted by W ildlife Intern ational, Ltd., Easto n, MD. Subm itted by ISAGRO S.p.A., Milano Italy. Report ID 544A-112. Study in itiated on February 12, 2003 and com pleted July 3, 2003.

64

### MRID 46578955. Sutherland, C., Kendall, T., and Kr ueger, H. 2002. IR5878: A 96-Hour Static Acute Toxicity Test with the Crayfish ( Procambarus clarkii ). Unpublished study perform ed by W ildlife Intern ational, Ltd., Easton Maryland. Laboratory Report Number: 544A-124. Study subm i tted by ISAGRO S.p.A. , Milano, Italy. The final report was issued July 14, 2003.
MRID 46578956. Palmer, S.J., Thom as, S.T., Kendall, T.Z., and H.O. Krueger. 2003. IR5878: A Se m i -Static Life-Cycle ToxicityTest with the Cladoceran (Daphnia magna ). Unpublished study perform e d by Wildlife Intern ational., Ltd., Easton, MD. Laboratory Project No. 544A-123. Study subm i tted by Isag ro S.p.A., Milano, Italy. Study initiated March 31, 2003 and completed Septem ber 22, 2003.
MRID 46578957. Palmer, S., Kendall, T., and Kr ueger, H. 2004. IR5878: A 96-Hour Shell Deposition Test with th e Eastern Oyster ( Crass o trea v i rgin ica ). Unpublished study perform ed by W ildlife Intern ational, Ltd, Easton, Mary land. Laboratory Report ID: 544A-106. Study subm i tted by ISAGRO S.p.A. , Milano, Italy. Study initiated May 23, 2002 and completed January 7, 2004.
MRID 46578959. Desjardins, D., T.Z. Kendall and H.O. Krueger. 2003. IR5878 50WG + ADJ2506: A 72 hour Toxicity Test with the Freshwater Alga ( Pseudokircheriella subcapitata ). Unpublished study perform ed by W ildlife International, L t d, Easton, MD, Project No. 544A-132 and subm itted by ISAGR O S.p.A., Milano, Ital y. Final report issued April 12, 2005.
MRID 46578967. Scacchi, A., R. Soddu, and G. Pizzing rilli. 2003. Anaerobic Aquatic Metabolism of 14C-IR5878 in Two Am erican Soils. Unpublished study perform e d by Isagro Ric er ca Srl, Envir o nm ental Chem istry, Metabolism & Environm ental Fate, Novara, Italy; and spons ored and sub m itted by Is agro S.p.A., Milano, Italy. Study No.: MEF.02.16. Experim e nt initiated on Augus t 26, 2002 and completed on Nove m ber 10, 2003; final report issued on Decem be r 12, 2003. 280 pp.
MRID 46578968. Scacchi, A., L. Vanini, and G. Pi zzing rilli. 2004. Soil ColumnLeaching of 14C-IR5878. Unpublished study perform ed by Is agro Ricerca Srl, Novara, Italy; sponsored and subm itted by Isagro S.p.A ., Milano, Italy. Study Num ber: MEF.03.17. Experim e nt initiation January 08, 2004 and completion April 02, 2004. Final report issued May 26, 2004. 162 pp.
MRID 46578970. Faltynski, K.H. 2005. Determ in ation of Aquatic Dissolution Rate of IR5878GR and pH 5 Hydrolysis Rate of IR 5878 Standard. Unpublished study perform e d by EN-CAS Analytical L aborat o r ies, W i nston-Salem , NC; and sponsored and subm itted by Isagro, U S A, Morrisville, NC. EN-CAS Study ID #: 04-0041. Experim e ntal phase (hydrolysis experim e nt) initiated and com ple ted on January 12, 2005. Final report issued March 17, 2005. 67 pp.

65

### MRID 46578971. Scacchi, A. and M. Trucco. 20 05. Adsorption-deso rption of 14C-IR5878 in Am erican Soils. Unpublished study perform e d by ISAGRO RICERCA S.r.l., Novara, Italy; spons ored and sub m itted by ISAGRO S.p.A., Milano, Ital y. StudyNum b er MEF.04.02. Experim e nt start date March 9, 2004, and com pl e tion date June 28, 2004. Final report issued January 10, 2005. 210 pp.
MRID 46578985. Cooley, T.A. 2005. IR5878 Fiel d Dissipation Study in Bare Ground Rice Soil. Unpublished study perform e d by Excel Research Services, Inc., Fresno, CA and PTRL W e st, Inc., Hercu l es, CA; and sponsored and subm itted by ISAGRO S.p.A., Milano, Italy. Study No.: ERS23044. PTRL W e st Project N o.: 1204W

. Experim ent initiation July 15, 2003 and com pletion February 14, 2005. Final repo rt issued May 19, 2005. 1013 pp.
MRID 46588507. van Dijk, A. 2004. Bioconcentration: Flow-through fish test with IR5878 in bluegill sunf ish ( Lepomis macrochirus ). Unpublished study perform e d b y RCC Ltd., Iting e n, Switzerland; sp onsored and s ubm itted by ISAGRO S.p.A., Milano, Italy. RCC Study No. 849257. Experim e nt initiated Ju ly 28, 2003, and com pleted February 10, 2004. Final report issued May 11, 2004. 68 pp.
MRID 46588508. Scacchi, A., L. Vanini, and D. Orio lo. 200 5. Aerobic Aquatic Deg r adation of 14C-IR5878 in Paddy-field Soil under Sunlight

. Unpublished study perf orm e d by Isagro Ricerca S r l, Environm ental Chem istr y, Metabo lism & Environm ental Fate, Novara, Italy; sponsored and subm itted by Isagro S.p.A. Departm e nt, Milano, Italy. Study No.: MEF.04.13. Experim e nt initiated on July 9, 2004 and com pleted on October 8, 2004. Final report issued on January 27, 2005. 198 pp.
MRID 46588509. Hennecke, D. 2002. Aquatic Photodegradation and Quantum Yield of IR5878. Unpublished study performed by Fraunhofer Institute for Molecular Biology and Applied Ecology, Schm allenberg , Germ any; sponsored and subm itted by ISAGRO S.p.A., Milan, Italy. GLP-Code: IS A-003/7-05. Experim e nt started July 26, 2002, and com pleted August 13, 2002. Final report issued Nove m ber 8, 2002. 52 pp.

66

## APPENDIX A. Prelim inary Data Screen.
UNITE D S T AT ES E N VIRONME N TAL PROTECTIO N AGENCY WAS H INGTON D. C., 20460
OFFI CE OF PREVENTION, PE STICIDES AND TOXIC SUBSTAN CES



### June 29, 2006 PC Code: 108209 DP Barcode: D330511 MEMORANDUM SUBJECT: Environm ental Fate and Effects New Ch e m ical Screen for Orthosulfam uron (PC Code 108209): Environm ental Fate and Ecological Effects Data Requirem ents. TO: Jam e s Tom p kins, Risk Manager HB/RD (75 05P) FROM: Greg Orrick, Environm ental Sc ientis t Christopher Salice, Biologist ERB4/EFED (7507P) THROUGH: Elizabeth Behl, Chief ERB4/EFED (7507P) The Environm ental Fate and Effects Division (E FED) has reviewed environm ental fate and ecological effects studies subm itted by Isagro in support of new chem ical regis tration for orthosulfam uron. This chem ical is described as a nonselective herbicide, which is labeled for use on rice as a both a granular (IR5878 0.5 GR ; 0.5% a.i.) and water dispersible granular (IR5878 50 WG; 50% a.i.) end-use product. This screen included:

• a check of the subm ission to ensure that a ll s tud ies trigge red by the use p atte rn ar e included in the package;

• an evaluatio n as to whether each stu dy is rev i ewable, i. e. , has no fatal flaws rendering the study scientifically invalid.

67

### Please no te that th is screen is not intended to be a com prehe nsive evaluation of the overall quality of specific studies, but an assurance that a reasonab l y com p lete package has been subm itted. Also, studie s that p ass the scre en ar e not autom atic ally assured of accep tance in support of the respectiv e data requirem e nt. The f o llowing table p r o v ides a br ief summary of the studies evaluated.

68

### Table 1. Chemical Screen for Ecologica l Effects Studies of Orthosulfamuron. Guideline Stud y Title MRI D Issues Review a b le (Yes/ N o )

71

- 1 Avian ac ute oral (N ort h er n b o b whi t e ) 4 626 01- 08 Y e s
Avian ac ute oral (M allard d u ck) 4 626 01- 07 Y e s

71

- 2 Avi an di et ary (N ort h er n b o b whi t e ) 4 621 90- 41

. Y e s
Avi an di et ary (M allard d u ck) 4 621 90- 40 Y e s
71

- 3 W i l d M amm als Not re qui re d. 71

- 4 a 1- Ge n. rep r od u c t i on (N ort h er n b o b whi t e ) 4 657 89- 50 Y e s

71

- 4b 1- Ge n. rep r od u c t i on (M allard d u ck) 4 657 89- 49 Yes

71

- 5 Fi el d m oni t o ri ng Not re qui re d.

72

- 1 Acut e t oxi ci ty (Blu eg ill sunfi s h ) 4 621 90- 43 Y e s
Acut e t oxi ci ty ( Rainbowtrout) 4 621 90- 42 Y e s

72

- 2 a Acut e t oxi ci ty (Da p hni a) 4 621 90- 44 Y e s

72

- 3 a Acut e t oxi ci ty estuarine/m arine fish (shee p s h ea d) 4 657 89- 51 Y e s

72

- 3b Oyster ac ute (sh e ll d e po sition ) 4 657 89- 57 Y e s

72

- 3 c Acut e t oxi ci ty (M arine shrim p ) 4 657 89- 52 Y e s

72

- 4 a Fish early life stage (Fathea dm i nn ow ) 4 657 89- 53 Y e s

72

- 4b C hr oni c t oxi ci t y (Da p hni a) 4 657 89- 56 Y e s

72

- 4 c C hr oni c t oxi ci t y (M arine shrim p ) 4 657 89- 54 Ap parent om i s si ono f s o m e end p o i nt s
. Yes

72

- 5 Fi sh Li fe cy cl e Not re qui re d. 72

- 6 Oy st er/ fi s h B C F Not re qui re d.
72

- 7 Field test (A qu at i c or gan i sm s) Not re qui re d.

1 22-1 a Terrest rial Plant No t Requ ired.



### 69Guideline Stud y Title MRI D Issues Review a b le (Yes/ N o ) Tier I Seed lin g e m ergence 1 22- 1b Terr e st r i al Plant Tier I Veg e tativ e Vig o r No t Requ ired.

12 3

- 1 Terrest rial Plant Tier II Seedling em ergence 4 657 89- 41 D ata app e ar rev iew ab le. Y e s

12 3

- 1 Terrest rial Plant Ti er I I Veget at i ve Vig o r 4 657 89- 42 NO AEC or EC 05 co ul d n o t b e det e rm i n ed f o r carrot. Yes

4 657 89- 31 Y e s 4 657 89- 32 Three re plicates use di n stead of rec o mmended fo ur
. Yes
4 657 89- 33 Y e s 4 657 89- 34 Hi g hi nhi bi t i o no f a d j uvant c o ntr o l ; im possi b l e t o di sce rnef fe ct s of o rth os ul f am uro n al one
. No
4 657 89- 35 N o t all exp e r i mental co nd itio n s r e po rted

. Y e s 12 3

- 2 Acut e t oxi ci ty al gae 4 657 89- 36 Y e s 4 657 89- 37 Y e s 4 657 89- 38 Y e s 4 657 89- 39 No t all test co ncen tration v e rified , h i gh er th an recomm ended te m p erature

. Yes
4 657 89- 40 No t all test co ncen tration v e rified , h i gh er th an recomm ended te m p erature

. Yes
4 657 89- 59 High er th anreco mmen d e d lig h t i nten s ity an d pH

. Yes

1 41- 1 Honeybee acut e contact 4 621 90- 46 Y e s

1 41- 2 Honeybee acut e foliar expos ure Not re qui re d.

N o n - gu id. A c ut e C r ayf i sh 4 657 89- 55 Y e s



### 70

### Table 2. Chemica l Screen for Environm enta l Fate Studie s of Or thos ulfamuron. Guideline Stud y Title MRI D Issues Revi ew a b l e ? 16 1

- 1 Hy dr ol y s i s 46 5 78 9 70 4 621 901 5 4 621 901 6 Collectively, these data a ppe ar re viewa b le for th e hy dr o l ysis d ata requ iremen t. Yes

16 1

- 2 Aq ue ous p h o t o l y si s 46 5 8 8 5 09 The dat aa ppear re vi ewa b l e
. Yes 1 61- 3 So il pho to lysis N o study N o t r e qu i r e d

. N /A 16 1 -4 Ai r p hot ol y s i s No st u dy Not re qui re d. N/A 1 62- 1 Aerob i c so il metab o lis m No stu dy Not re quire d. N/A

1 62- 2 Anae robic s o il metab o lis m No stu dy Not re quire d. N/A

1 62- 3 Anae robic a quatic metab o lis m 46 5 7 8 9 67 The dat aa ppear re vi ewa b l e
. Yes
1 62- 4 Aerobic aquatic metab o lis m 4 658 850 8 4 621 901 7 The dat aa ppear re vi ewa b l e
. Yes

1 63- 1 Batchequ ilib ri um / aged leachi ng 4 657 896 8 4 657 897 1 4 621 901 8 4 621 907 4 The dat aa ppear re vi ewa b l e
. Yes

1 63-2 Lab vo latility No study No t requ i red

. N/A 1 64- 1 Terrest rial field di ssi pat i o n No stu dy Not re quire d. N/A

1 64- 2 Aqu atic field di ssi pat i o n 4 657 898 5 The s u bm itt e d st udya p pears r e vi ewa b l e f o r th e wat e r di spe r si bl e granul ar fo rm ul at i on. The s u bm issio n requirem ent for a study of th e g r anul ar f

o rm ul at i on has beenwai v ed ( D P Bar c od e 32 028 3) , as th e activ e in gred ien t in bo th fo rm u l atio n s is exp ected t o be have si m i larl yi na quat i c ecosy st em s with in24 h ours of ap p lication

. Yes

1 65- 4 Fish bi oacc um ul at ion 46 5 8 8 5 07 The dat aa ppear re vi ewa b l e
. Yes



### 71

## APPENDIX B. En viro nmental Fate Data.
Detailed inf o rm ation re garding the f ate and tran sport of orthosulfam uron in the environm ent is provided in the study summaries below.
161-1. Hyd r olysis MRID 46219015 (Supplemental) The hydrolysis of [phenyl-U- 14 

### C]-labeled 1-(4,6-dim ethoxypyrim idin-2-yl)-3-[2­ (dim ethylcarbam oyl)phenylsulfam oyl]urea (orthosulfam uron, ra diochem i cal purity > 97%), at 1 μ g a.i./m L, was studied in sterile aq ueous buffe red pH 4 (0.01M acetate), pH 7 (0.01M citrate), or pH 9 (0.01M borate) solutions that were inc ubated in the dark in three experim e nts: A definitiv e experim ent was conducted at 25 ° C with pH 7 or pH 9 solutions for up to 176 days. The other two experim e nts were conducted at 50°C. In the pH 7 buffer at 25°C, [ 14 

### C]orthosulfam uron decreased from 96.99% of the applied at day 0 to 76.14% at 8 days post-treatm ent and 32.91% at 37 days, dissipating with a half-life of 22.1 days. In the pH 9 buffer at 25°C, [ 14 

### C]orthosulfamuron decreased fr om 96.57% of the applied at day 0 to 56.19% at 176 days, dissipating with a half-life of 231 days. Table B-1 lists the reported half-life and transform ation produc t data of this study and MRIDs 46219016 and 46578970. This study was classified as supplem ental si nce the sterility of th e test solutions was not confirmed and only pH 7 and pH9 buffers were studied at 25°C.

Table B-1. Orthosulfamuron Hydrolysis Ha lf-lives and Transformation Products.

pH Temperatu re ( ° C) Half -life Transformation products Major Minor 5 25 0.442 days Undeterm ined. Undeterm ined. 7 25 24.4 days DBS acid (H1) DBS am ine (H2), DB am ine (H4) 9 25 228 days H1, H4 H2

4 50 0.02 days H1, H4, DOP urea (H5) H2, DOP am ine (H6)
7 50 1.2-1.5 days H1, H4, H5, H6 H2
9 50 8.0-8.6 days H1, H2, H4, H5, H6 None.
MRID 46219016 (Supplemental) The hydrolysis of [pyrimidinyl-5- 14 

### C]-labeled 1-(4,6-dim e thoxypyrim idin-2-yl)-3-[2­ (dim ethylcarbam oyl)phenylsulfam oyl]urea (orthosulfam uron, ra diochem i cal purity > 9 5 %), at

72

### 1.25 μ g a.i./mL, was studied in the dark at 50 ° C in sterile aqueous buffered pH 4 (0.01M acetate), pH 7 (0.01M citrate) and pH9 (0.01M b orate) solutions for 60 minutes, 52 h ours and 13 days, respectively. Orthosulfam uron dissipated with a first-order half -life of 0.015 days (21.6 m i nutes) in the pH 4 buffer, 1.2 days in the pH 7 buffer, and 8.6 days in the pH 9 buffer. Two transform ation products were identified: N-(4,6-dim e thoxypyrim idin-2-yl)urea (DOP urea; H5), which was a m a jor transform ation product at all pHs, and 2-am ino-4,6-dim e thoxypyrim idine (DOP am ine; H6), which was a m i nor transform a tion product at pH 4 and a m a jor product at pH 7 and 9. This study was classi fied as supplem ental, as it was conducted only at 50 ° C and the ster ility of the tes tso lutions was not confirm e d. MRID 46578970 (Supplemental) Unlabeled orthosulfam uron (IR5878; 1-(4,6-dim ethoxypyrimidin-2-yl)-3- [2-(dim ethylcarbam oyl)phenylsulfamoyl]-urea) at 20 m g a.i./L was studied in an aqueous pH 5 (phthalate) buffered solution in the dark at 25° C for 24 hours. The level of orthosulfam uron decreased from 87% of the nom inal concentration at the start of the experim e nt to 51% at 8 hours post-treatm ent and 18% at 24 hours (study te rm ination). The first- order half-life in the pH 5 buffer solution was 10.6 hours (0.442 days), as reported in Table B-1

. No degradation products were analyzed and a hydrolytic tran sform ation pathway was not proposed. The study was classified as supplem ental since the m ateri al balance was incom plete and no experim e nts were conducted on technical grade m aterial at pH7 and pH 9.
161-2. Aqueous Photolysis MRID 46588509 (Supplemental) The aqueous phototransform ation of unlabeled or thosulfam uron, at 10, 20, and 30 m g a.i./L, was studied in a pH 9 buffer (borate, m olarity not reported) solution that was irradiated continuously using a filtered xenon lamp for 166 hours at 25oC

. The nominal intensity of the lamp was 700 W/m2



### . Orthosulfamuron was relatively stable in the irradiated solutions, declining 4.9-5.6% of the applied am ount during the irradiation period. Orthosulfam uron was stable in the dark controls. No transform ation products were isolated from either the irradiated sam p les or dark controls. Volatiles were not coll ected. Orthosulfam uron dissipated with first-order half-lives of 85, 87, and 98 days, applied at 10, 20, and 30 mga.i./L, respectively, yielding a half-life (com bined data) of 90 days based on the continuo us irradiation used inthe study. These halflives are of uncertain value sin ce they were extrapolated wellbeyond the 6.9-day duration of the study. Based on a 12-hour light/12- hour dark cycle, the calculate d phototransform ation half-life of orthosulfam uron is 180 days. An envi ronm ental phototransform ation half-life of orthosulfam uron could n o t be determined becau s e the intens ity of the artificial light w a s not com pared to natural sunlight. This study was classified supplem ental because >94% of the applied remained undegraded at study term ination ( ca. 7 days post-treatment) ; ste r ility was not conf irm ed; the inten sity of the artif i c i al lightwas not com pared to natural sunlight; and raw sam p le concentration and tem p er ature data were not reported.

73

### 162-3. Anaerobic Aquatic Metabolism MRID 46578967 (Supplemental) The anaerobic biotransform ation of [ 14 

### C-5-pyrim i dinyl]-labeled and [ 14 

### C-U-phenyl]-labeled orthosulfam uron was studied in darkness at 20 ± 2°C in a pond water-loam sedim e nt system (water pH 7.8, dissolved organic carbon not reported; sedim e nt pH 6.9, organic carbon 0.87%) from Arkansas, for 180 days and in a pond water-cl ay sedim e nt system (water pH 7.7, dissolved organic carbon not reported; se dim e nt pH 6.0, organic carbon 1.8%) from California, f o r 150 days. The water/sedim e nt ratio used was 2.2:1 fo r the Arkansas water-loam sedim e nt system and 2.5:1 for the California water-clay sedim e nt system

. First-order half-lives were calculated by counting non-extracted residues as parent compound, since m u ltip le solv ent sy stem s were not em ployed in a re ason able ex trac tion attem p t. The half

lives f o r pyr im idinyl-5-[ 14 

### C]-labeled orthosulfam uron in the water, sediment, and total (watersedim e nt) system were 68, >365, and 217 days, resp ectively, in the m i crocosm from Arkansas. Respective half-lives for orthosulfamuron pare nt alone were 68, 124, and 89 days. Three m a jor degradation products were observed: o-de sm ethyl IR5878 (S 9), m axi m um of 12.63%, 7.28%, and 17.47% in the water, sedim e nt, and total sy stem , respectively; DOP urea (S12), m axim um of 2.31%, 11.39%, and 12.47% in the water, sediment , and total system , re spectively; and S11 (com posed of 5 com pounds), m axi mum of 14.59 %, 8.59%, and 23.18% in the water, sedim e nt, and total system , respectively. One m i nor transform ation product was observed: DO P am ine (S13), with m axi m ums of 0.42%, 0.75%, and 1.14% in the water, sediment, and total system , respec tive l y. The first-order half-lives counting non-ex tracted residues as parent com pound for [ 14 

### C-U-phenyl]-labeled orthosulfam ur on in water, sedim e nt, and to tal (water-sed im ent) system were 63, >365, and 142 days, respectively, in the m i crocosm from Arkansas. Respective halflives for orthosulfam uron parent alone were 63, 117, and 80 days. Three m a jor degradation products were observed: DBS acid (S1), m axi mum of 6.78%, 6.23%, and 12.01% of the applied am ount in the water, sedim e nt, and total syst em , respectively; S9, m axi m um of 11.70%, 7.94%, and 18.59% in the water, sedim e nt, and total sy stem , respectively; and S5 (com posed of 8 com pounds) , m axim um of 15.10%, 6.77%, and 21.86% in the water, sedim e nt, and total system , respectively. Minor transform ation products we re DBS am ide (S2), with m axi m ums of 3.02%, 2.1%, and 4.23% in the water, se diment, and total system , respec tively, and DB am ine (S4), with m axi m ums of 4.92%, 2.56%, and 6.41% in the wate r, sediment, and total system , respectively. Dissipation occurr ed m o re re adily in the Calif orn i a system

. The first-order half-lives counting non-extracted residues as pare nt compound for pyrim idinyl-5-[ 14 

### C]-labeled orthosulfamuron in the water, sedim e nt, and total (water-sed im ent) system were 25, >365, and 161 days, respec tive l y, in the m i cro cosm f

r om Calif ornia. Respectiv e half -liv es for orthosulfamuron parent alone were 25, 57, and 41 days. Three m a jor transform ation products were observed: S9 at a m axi m um of 9.51%, 3.29%, and 12.21% in th e water, sedim e nt, and total system , respectively; S12, m axi mum of 1.27%, 18.27%, and 18.97% in the water, sedim e nt, and total system , respectively; and S 11, m aximum of 13.21%, 7.73%, and 20.94% of the applied am ount in the water, sedim e nt, and total system , respectively.

74

### The first-order half-lives counting non-extract ed residues as parent com pound for [phe nylU- 14 

### C]-labeled orthosulfam uron in the water, sedi m ent, and total (water -se d im ent) system were 23, >365, and 88 days, respectively. Respective ha lf-lives for orthosulfamuron parent alone were 23, 39, and 41 days. Three m a jor transformation products were observed: S1, m axim um of 21.59%, 17.06%, and 38.65% in the water, sedime nt, and total system , respectively; S 9, m axi m um of 8.96%, 5.27%, and 13.11% in the water, sediment, and total system , respectively; and S5, m axim um of 12.39%, 3.71%, and 16.10% in the water, sedim e nt, and total system , respec tive l y. The study was classified as supplem ental because m i crobial biom ass was not m easured at any tim e in sedim ent or water and th e un extra ctab l e fraction m ay not have been thoroughly extracted; non-extractable [ 14 

### C]residues in sedim e nt were m easured at >10% by day 15.
162-4. Aerobic Aquatic Metabolism MRID 46219017 (Supplemental) The biotransform ation of [pyrim idinyl-5- 14 

### C]- and [phenyl-U- 14 

### C]-labeled orthosulfamuron was studied in water-loam sedim e nt (water pH 7.8, organic carbon not reported; sedim e nt pH 6.2– 6.9, organic carbon 0.87%) system s from Arkansas for 90 days and in water-clay sedim e nt (water pH 7.7, organic carbon not reported; sedim e nt pH 5.6–6.0, organic carbon 1.8%) system s from California for 61 days under aerobic c onditions in darkness at 20 ± 2oC. The sedim e nt:water ratios used were approxim ately 1:2.2–2.5. Dissipation and transform ation of [ 14 

### C] orthosulfam uron occurred m o derately in bo th system s, but was m or e rapid in the waterclay sys t em s com p ared to the water-loam systems. First-order half-lives were calculated by counting non-extracted residues as parent compound, since m u ltip le solv ent sy stem s were not em ployed in a re ason able ex trac tion attem p t. The f i rstorder half-lives for pyrim idinyl-5-[ 14 

### C]-labeled orthosulfam uron in th e water, sed i ment, and to ta l (water-sedim ent) system were 29.1, >365, and 70.5 days, respectively, in the m i crocosm from Arkansas. Respective half- lives for orthosulfamuron parent alone were 29.1, 39.6, and 40.6 days. S12 was observed as a m a jor transform ation product occurring at m axim um s of 6.09%, 42.50%, and 47.78% of the applied in water, sedim e nt, and total system , respectively. S9 was observed as a m i nor degradate with m axi m ums of 6.68%, 2.69%, and 9.37% in water, sedim e nt, and total sys t em , respectively. The first-order half-lives counting non-extract ed residues as parent com pound for [phe nylU- 14 

### C]-labeled orthosulfam uron in the water, sedi m ent, and total (water -se d im ent) system were 27.6, >365, and 59.2 days, respectively. Respective ha lf-lives for orthosulfam uron parent alone were 27.6, 41.5, and 36.3 days. S1 was observed as a m a jor degradate with m axi m um s of 46.53%, 9.24%, and 55.77% in water, sedim e nt, and total system , respectively. The minor degradates were: S9, with m axi m ums of 5.97%, 2.06%, and 8.03% in water, sedim e nt, and total system , respectively, and S2, with m a xim ums of 3.25%, 0.87%, and 4.07% in water, sedim e nt, and total sys t em , respectively.

75

### In the m i crocosm from California, the first-o r de r half-lives c ounting non-extracted residues as parent com p ound for pyrim idinyl-5-[ 14 

### C]-labeled orthosulfam uron in the water, sediment, and total (water-sedim ent) system were 13.1, >365, and 65.4 days, respectively. Respective halflives for orthosulfam uron parent alone were 13.1, 38.4, and 24.1 days. S12 was observed as a m ajor transform ation product occurring at m aximum s of 6.66%, 37.70%, and 40.52% of the applied in water, sedim ent, and total system , re spectively. S9 was observed as a m i nor degradate with m axi mum s of 4.98%, 2.32%, and 7.30% in wate r, sediment, and total system , respectively. The first-order half-lives counting non-extr acted residues as pare nt compound for phenylU-[ 14 

### C]-labeled orthosulf am uron in the water, sedi m ent, and total (water -se d im ent) system were 12.1, 101.9, and 30.3 days, respectively. Respective half -lives for orthosulfam uron parent alone were 12.1, 35.4, and 21.3 days. S1 was observed as a m a jor degradate with m axi m um s of 49.88%, 11.11%, and 60.86% in water, sedim e nt, and total system , respectively. The m i nor degradates were S9, with m axim ums of 4.60%, 1.84%, and 6.13% in water, sedim e nt, and total system , respectively, and S2, with m a xim ums of 2.81%, 1.28%, and 4.09% in water, sedim e nt, and total sys t em , respectively. This study is class i fied as supplem ental becau se multiple solvent systems were not employed in a reasonable extraction attem pt, leavi ng 11–33% of the applied unextracted. MRID 46588508 (Unacceptable) The aerobic biotransform ation of [ 14 

### C-5-pyrim idinyl]-labeled and [ 14 

### C-U-phenyl]-labeled orthosulfam uron, at 0.75 m g a.i./L (equivalent to 75 g a.i./ha), was studied outdoors for 62 days in a water/loamy sand se dim e nt (water pH 7.79, organic carbon not reported; sedim e nt pH 6.3, organic carbon 1.30%) from Italy. A ccurate half-liv es could not be determined because >50% of the applied orthosulfam uron dissipated between tim e 0 and the next sam p ling interval (1 day post-treatm ent). In the s y stem treate d with [ 14 

### C-5-pyrim idinyl]orthosulf am uron, the only m ajor transform ation product was S12, at an average m axi m um of 56.95% of the applied at 5 days post-treatm e nt (m axi m um s 14.42% at 7 days in the water, 44.52% at 5 days in the sedim e nt), decreasing to 32.78% (2.48% in water, 30.30% in sedim e nt) at study term ination. The three identified minor transform ation products, S9, S13, and S15, each averag ed a m axi mum of <3% of

the applie d in the tota l system

. In the system treated with [ 14 

### C-U-phenyl]orthosulfamuron, the only m ajor transform ation product w as S1 at a m axim um of 54.47% of the applied in the total system at 7 days post-treatm ent (m a x im ums 36.63% at 7 days in water, 19.45% at 4 days in sedim e nt), decreasing to 13.13% (6.99% in wa ter, 6.14% in sedim e nt ) at study term ination (62 days). T he three identified m i nor transf orm a tion products were S2, S4, and S9; each averaged a m axi m um of <2% of th e applied in the tota l sys t em
. The study is classified as unacceptable because th e experim ents were cond ucted outdo ors, where sam ples were exposed to sunlight and fluctuat ing tem peratures. Radioactivity was lost over tim e, as the sam p les were open to the environm ent and volatiles were no t colle cted, re sulting in poor m aterial balance.
163-1. Leaching-Adsorption/Desorption

76

### MRID 46219074 (Supplemental) The adsorption/desorption characteris tics of [ 14 

### C-U-phenyl]-labeled orthosulfam uron were studied in four Italian soil s in a batch equilibrium experim e nt: a sandy loam soil (pH 6.29, organic carb on 1.33%); two silt lo am soils (pH 5.71, organic carbon 2.03 % and pH 6.78, organic carbon 1.00%); and a clay loam soil (pH 7.98, organi c carbon 2.30%). T he adsorption phase of the study was carried out by equili brating air-dried soil with [ 14 

### C]orthosulfam uron at nom i nal test concentrations of 0.28, 1.4, 7.0, and 35.0 m g a.i./kg soil f o r all test soils at 20 ± 2 ° C for 2 hours; lighting conditions were not reported. The equilibrating solution used was 0.01M CaCl 2 

### with soil:so l ution r atio s of 1:7 (w:v) f o r all test s o ils. The de sorption phase of the study was carried out by replacing most of the adsorpti on solution with an equivalent volum e of 0.01M CaCl 2 

### solution and equilibrating for 2 hours at 20 ± 2 ° C; lighting conditions were not reported. Four desorption cycles were conducted fo r all test soils. Soil properties and adsorption/desorption data are summarized in Table B-2

.

Table B-2. Orthosulfamuron Adsorp tion/Des orption in F our Soils. Textural Classification B1 Sandy Loam G2 Silt Loam M2 Silt Loam VM-1 Clay Loam % san d 62 .0 28 .3 37 .0 24 .3 % silt 3 2 .3 5 4 .4 5 4 .3 4 6 .7 % cl ay 5. 7 17 .3 8. 7 29 .0 % o rgani c m att er 2. 29 3. 49 1. 72 3. 96 % o rgani c carb on 1. 33 2. 03 1. 00 2. 30 pH 6. 29 5. 71 6. 78 7. 98 C E C mE q/ 100 g 7. 65 12 .1 7 10 .7 20 .0 6 Ads o rp ti onp h ase K d 6. 01 ±3

. 2 0 8. 62 ±2

. 4 6 6. 26 ±1

. 4 5 6. 11 ±0

. 6 3 K f 3. 76 6. 62 5. 47 5. 72 1/n 0. 75 1 0. 85 6 0. 92 0 0. 95 5 K oc 28 3 32 6 54 7 24 9 Deso rpti on ph ase K d 58 .0 ±1 7

. 6 42 .8 ±1 2

. 2 10 5 ± 3 5 18 .1 ±3

. 0 K f 35 .8 32 .0 14 1 20 .3 1/n 0. 90 2 0. 93 5 1. 07 4 1. 03 3 K oc 26 9 0 15 8 0 14 1 00 88 2 C E C = C at i on exchan ge ca pa ci ty K oc = K f x 10 0 % ÷ (% o r gani c car bo n) 

### The study is classified as supplem ental becau se m aterial balances were determ ined for the highest test concentrations for all tes tsoils, rathe r than f o r a l l test concentrations; non e of the tes t soils had an organic m atter content of < 1%; and adsorption phase supernatants were not adequately d ecanted and vol um es were not reported. MRID 46578971 (Supplemental) The adsorption/desorption characteris tics of [ 14 

### C- 5-pyrim idinyl]

- labe lled orthosulfam uron were studied in a batch equilibrium experim e nt in two sandy loam soils (pH 6.5, organic carbon 1.04%; pH 5.7, organic carbon 0.35%) from Arkansas, a sand soil (pH 4.7, organic carbon 1.03%) from Minnesota, a clay loam soil (pH 5.4, organic carbon 3.01%), a loam soil (pH 7.4,

77

### organic carb on 1.8%) fro mNorth Dakota, and a s ilt loam soil (pH 7.5, organic carbon 0.92%) from Italy. The adsorption phase of the study was carried out by equilibrating air-dried soil with [ 14 

### C-5-pyrim idinyl]orthosulfam uron at 0.25, 0.75, 2.5, 7.5, and 25.0 m g a.i./kg soil at 20 ± 2°C for 2 hours (lighting con ditions were not reporte d)

. The equilibrating so lution used was 0.01M CaCl 2 

### , with soil/solution ratios of 1:5 (w:v) for all test soils. The desorption phase of the study was carried out by replacing the ad sorption solution with an equivale nt volum e of pe sticide-free 0.01M CaCl 2 

### solution and equilibrating at 20 ± 2°C fo r 2 hours (lighting conditions w e re not reported). T he desorption step was conducted tw i ce for all test soils. Soil properties and the adsorption/desorption data are summarized in Table B-3.

Table B-3. Orthosulfa muron Adsorpti on/Desorption in S i x Various Soils. Property Ark-1 Ark-2 Benson M-CL PC-1 Pratt So il tex t ure Sandy lo am Sandy lo am Sand Clay lo am Silt lo am Lo am %San d 58 .2 5 60 .0 0 87 .2 5 24 .7 5 13 .5 0 42 .0 0 %Silt 3 6 .25 3 2 .00 1 1 .00 4 4 .50 7 2 .50 3 8 .00 %C l ay5. 50 8. 00 1. 75 30 .7 5 14 .0 0 20 .0 0 p H(0 .0 1 CaCl 2 ) 6. 50 5. 66 4. 70 5. 37 7. 50 7. 40 Or gani c car bo n (%) 1. 04 0. 35 1. 03 3. 01 0. 92 1. 80 Or gani c m att er (% ) 1. 77 0. 60 1. 75 5. 12 1. 56 3. 06 C E C (m eq/ 100 g) 7. 19 5. 89 1. 46 27 .1 8 17 .0 1 22 .4 0 Ads o rp tion K f

2. 37 8. 17 3. 61 19 .7 2. 00 6. 86 1/n 0. 97 4 1. 06 2 1. 15 2 0. 98 0 1. 01 9 0. 99 0 K oc 22 8 23 3 0 35 0 65 3 21 7 38 1 Deso rpti on K f

4. 01 8. 38 5. 11 13 .8 3. 17 4. 72 1/n 1. 04 8 1. 01 9 0. 93 5 0. 95 8 1. 02 3 0. 99 1 K oc 38 5 23 9 0 49 6 46 0 34 5 26 2 Ark

- 1 : Ark an s as sandy lo am so il; Ark-2 : Ark ansas sandy lo am so il; Ben s o n : Mi nn e so ta sandso il; M-CL: clay lo am so il fro m North Dako ta; PC-1 : silt lo am so il fro m Italy ; Pratt: lo am so il fro m North Dako ta C E C = C at i on exchan ge ca pa ci ty K oc = K f x 10 0 % ÷ (% o rgani c car bo n) 

### The study is classified as supplem ental becau se m aterial balances were determ ined only for test soils treated at one test concentration, rather than for all test concentrations/test soil groups. MRID 46219018 (Acceptable) The columnleach ing of aged [ 14 

### C-5-pyrim idinyl]-labelled orthosulfam uron and [ 14 

### C-U-phenyl]­ labeled orthosulfam uron applied at a rate of approxim ately 75 g/ha in a soil:water system (Arkansas loam soil, 51% sand, 38% silt, 11% clay, pH 6.2, organic m atter 1.5%; Arkansas well water, pH 7.8) was investigated. The columns we re continuously leached under saturated conditions with 997 mL (equivalent to 508 mm of rainfall) of 0.01M Ca Cl 2 

### solution in the dark for 9 days (tem perature not reported), resulting in ca. 6 pore volum es of l eachate. The elution

78

### flow rate was 4.6 mL/hour and th e in filtration rate was 0.23 cm /hour

. Ba sed on TLC analyses of leachate samples, [ 14 

### C]orthosulfam uron was not found in leachate, whereas several transform ation products were in leachate. In the [ 14 

### C-U-phenyl]-labeled orthosulfam uron portion of th e study, m a jor tran sformation p r oduct, S1, accounted for 44.26–50.56% of the applied radioactiv ity in the leach ate. Minor transform ation products S9, S2, and S5 accounted for 3.59–3.76%, 7.32–8.01%, and 1.33–2.47% of the applied, respectively. Minor transform ation product S 4 was found in soil from one column , com prising 3.71% of the applied. In the [ 14 

### C-5-pyrim idinyl]-labelled orthosulfam uron columns, transform ation products S9 and S11, accounting for 4.07 –4.57% and 0.21–0.24% of the a pplied radioactiv ity, respectiv e ly, were found in the leachate. MRID 46578968 (Supplemental) The columnleach ing of unaged [ 14 

### C-5-pyrim idinyl]-labelled orthos ulfam uron was investigated in two sandy loam soils (58.25% sand, 36.25% silt, 5.5% clay pH 6.50, organic m atter 1.79%; 60% sand, 32% silt, 8% clay, pH 5.66, organi c m atter 0.60%) from Arkansas, a sand soil (87.25% sand, 11% silt, 1.75% cl ay, pH 4.70, organic m atter 1.77 %) from Minnesota, a clay loam (24.75% sand, 44.5% silt, 30.75% clay, pH5.37, organic m atter 5.18%) from North Dakota, and a silt loam (13.50% sand, 72.5% silt, 14% clay, pH 7.50, organic m atter 1.58%) from Italy. The column s were continuously leached under saturated cond itions for 11 9 hours with 997 mL (equivalent to 508 mm of rainfall) of 0.01M Ca Cl 2 

### solution, resulting in ca. 5-6 pore volum es of leachate. The flow rate ranged from 8.42 to 125.11 m L /h, and the infiltration rate ranged f r om 0.43 to 6.37 cm /h. For the Ark-1 sandy loam soil, an average of 8.68% of the applied radioac tivity was recovered in the 1s segm ent (top 5-cm segm ent), 16.06% in the 2s (5–10 cm ) segm ent, 26.71% in the 3s (10– 15 cm ) segm ent, 31.11% in the 4s (15–20 cm ) s egm ent, 14.84% in the 5s (20–25 cm) segm ent, and 1.27% of the applied in the 6s (25–30 cm ) se gm ent. Based on TLC analysis, [ 14 

### C]orthosulfam uron comprised 88.51% of the applied, of which 6.18%, 13.08%, 24.35%, 29.47%, 14.33%, and 1.10% of the applied was recovere d in soil segm ents 1s, 2s, 3s, 4s, 5s, and 6s, respectively. Transform ation product S12 (DOP urea) was found in the top 25 cm of soil and totaled 8.22% of the app lied radioactivity. T r ansform ation product S13 (DOP am ine) was not detec t ed. T o tal ex tra cta ble [ 14 

### C]residues accounted for 96.86% of the applied, and unextractable residues accounted for 1.81% of the applied. Ra dioactivity in the leachate sam p les totaled 0.63% of the applied. Based on TLC analysis, [ 14 

### C]orthosulfam uron comprised all of the radioactiv ityrecovered in the leachate sam p les. For the Ark-2 sandy loam soil, an average of 31. 32% of the applied radi oactivity was recovered in the 1s segm ent, 50.13% in the 2s segm ent, and 15.60% of the applied in the 3s segm ent. Radioactivity was not recovered in the 4s, 5s, and 6s soil segm ents. Based on TLC analysis, [ 14 

### C]orthosulfam uron comprised a total of 72.51 % of the applied, of which 18.64%, 40.32%, and 13.55% of the applied was recovered in soil segments 1s, 2s, and 3s, respectively. Transform ation product S12 (DOP urea) was found in the top 15 cm of soil and totaled 22.22% of the applied. Transform ation product S13 (DOP am ine) was found in the top 5 cm of soil and totaled 0.29% of the applie d. Total extractable [ 14 

### C]residues accounted f or 95.00% of the

79

### applied, and unextractable residue s accounted for 2.05% of the a pplied. Radioactivity in the leachate samples was not detected. For the Benson sand soil, an aver age of 32.60% of the applied was recovered in the 1s segm ent, 29.86% in the 2s segm e nt, 22.65% in the 3s segm ent, 9.26% in the 4s segm ent, and 0.46% of the applied in the 5s segm ent. Radioactivity was not recovered in the 6s (bottom ) soil segm ent. Based on TLC analysis, [ 14 

### C]orthosulfam uron c o m prised a to tal of 52.80% of the applied, of which 11.95%, 17.31%, 15.99%, and 7.55% of the applied was recovered in soil segm ents 1s, 2s, 3s, and 4s, respectively. Transform a tion product S12 was found in the top 20 cm of soil and totaled 38.16% of the applied. Transform ation product S13 was found in the top 15 cm of soil and totaled 1.35% of the appl ied. Total extractable [ 14 

### C]residues accounted for 92.44% of the applied, and unextractable residue s accounted for 2.39% of the a pplied. Radioactivity in the leachate samples was not detected. For the M-C L clay loam soil, an average of 84.60% of the applied was recovered in the 1s segm ent, 10.94% in the 2s segm ent, and 0.25% of th e applied in the 3s segm ent. Radi oactivity was not recovered in the rem a ining 4s, 5s, and 6s soil segm ents. Based on TLC analysis, [ 14 

### C]orthosulfam uron comprised a total of 72.22% of the applied, of wh ich 64.01% and 8.21% of the applied was recovered in soil segm ents 1s and 2s, respectively. Transform ation product S12 was found in the top 10 cm of soil and totaled 18.04% of the applied. Transform ation product S13 was found in the top 5 cm of soil and to taled 0.67% of the applie d. Total extractable [ 14 

### C]residues accounted for 91.17% of the applie d, and unextractable residues accounted for 4.62% of the applied. Radioactivity in the leachate sam p les was not detected. For the PC-1 silt loam soil, an av erage of 13.50% of the app lied was recovered in th e 1s segm ent, 11.16% in the 2s segm ent, 15.37% in the 3s segm ent, 20.61% in the 4s segm e nt, 22.63% in the 5s segm e nt, and 10.08% of the applie d in the 6s segm ent. Based on TLC analysis, [ 14 

### C]orthosulfam uron comprised a total of 80.99% of the applied, of which 10.78%, 8.39%, 13.18%, 18.31%, 20.77%, and 9.56% of the applied was recovered in soil segm ents 1s, 2s, 3s, 4s, 5s, and 6s respectively. Transform ation product S12 was found in all soil segm ents and totaled 9.68% of the applied. Tr ansform ation product S13 was not detected. Total extractable [ 14 

### C]residues accounted for 90.65% of the applie d, and unextractable residues accounted for 2.70% of the applied. Radioactivity in the leach ate sam p les totaled 2.09 % of the app lied. TLC analys is sho w ed that [ 14 

### C]orthosulfamuron acco unted for all of the radio activ ity reco vered in the leachate samples. The study is classified as supplem ental since only one com pound ring was radiolabelled and the com pound was not aged in soil. This study is valid for orthosulfam uro n parent, but does not evaluate the leach ing potential of m a j o r degrad ates. 164-2. Aquatic Field Dissipation MRID 46578985 (Supplemental) Orthosulfamuron (IR5878 50W G , 50% a.i.) was applied once at a target application rate of 375 g a.i./ha (0.33 5 lb a.i. /A; which is 500 % of the nor m a l use rate) onto a bare ground plot of silt lo am

80

### soil (32% sand, 56% silt, 12% clay, pH 6.7, 0.8% or ganic m atter) in Arkansas and a bare ground plot of silty clay loam soil (18% sand, 49% silt, 33% clay, pH7.7, 2.2% organic m atter) in California. The plots w e re flooded with water 1–2 days following the test application to approxim ate the tim i ng of herbicide applicati on to rice. Soil (0–60 cm de pth), water, and sedim ent (0–5 cm depth) sam p les were collected for analysis of orthosulfam uron and three transform ation products. Soil sam ples were co llected through 550–553 days post-treatm ent and water and sedim e nt samples were collected from 3 days to 2 months post-treatm ent, at which tim e the water was drained from the plots. At the Arkansas test site, orthosulfamuron dissipated in the soil, sedim e nt, and water with firstorder half-lives of 4.1 days (r2 

### = 0.9119), 6.2 days (r2 

### = 0.8864), and 6.4 days (r2 

### = 0.7323), respec tive l y. Orthosulfamuron was detected inthe 0- to 15-cm soil depth at a m ean concentration of 0.069 mg/kg at day 0, which is 33.7% of the theoreticalam ount (calculated based on a theoretical value of 0.205 m g /kg determ ined for the 0–15 cm soil de pth based on the application rate at 0.375 kg a.i./ha and the site specific bulk density of 1.22 g/cm 3 

### ). Orthosulfam uron decreased to 0.046 mg/kg by 1 day and 0.015 m g/kg by 7 days, and wa s last detected at0.006 m g/kg (single replicate) at 15 days post-treatm ent. It was onl y detected once in the 15- to 30-cm soil depth, at 0.007 m g/kg (single replicate) at day 0, and was not detected belo w that depth. The levels of orthosulfam uron and three degradation products insoil (0–15 cm depth), sedim e nt, and water are shown in Tables B-4 through B-6

.

Table B-4. Mean Concentration of Orthosul famuron Residues in Arkansas S(soil 0–15 cm), Expressed as mg/kg Soil.

Days Posttreatment Average Residue in the 0–15 cm Soil Depth (m g/kg)

Orthosulfamuron DOP U rea (S12) o-Desm ethyl Orthosulfamuron (S9) DBS Acid (S 1) 0 0. 06 9 0. 00 7 a ND ND 1 0. 04 6 0. 00 6 a ND ND 7 0. 01 5 0. 02 6 ND 0. 04 7 b 15 0. 00 6 a0. 02 6 ND ND 22 <0. 0 0 5 0. 02 5 ND 0. 02 5 b 31 <0. 0 0 5 0. 02 3 ND ND 60 <0. 0 0 5 0. 02 6 ND ND 12 3 <0. 0 0 5 0. 02 3 a ND – 18 6 – 0. 04 9 – – 27 3 – 0. 03 3 – – 36 4 – 0. 01 8 – – 46 2 – 0. 03 7 – –



### 81

### Table B-4. Mean Concentration of Orthosul famuron Residues in Arkansas S(soil 0–15 cm), Expressed as mg/kg Soil.

Days Posttreatment Average Residue in the 0–15 cm Soil Depth (m g/kg)

Orthosulfamuron DOP U rea (S12) o-Desm ethyl Orthosulfamuron (S9) DBS Acid (S 1) 55 0 – 0. 01 7 – – Orthosulfamuron, S12 and S9: LOD = 0. 0006 mg/kg and LOQ = 0.005 mg/kg. S 1 : LOD = 0.008 mg/kg and LOQ = 0.02 mg/kg.
a S ingle r e pli c ate valu e (o ther rep lic ates <LOQ) b Mean o f duplicate detects (w ith the third replicate <LOQ)



### Table B-5. Mean Concentration of Orthosulfa muron Residues in Arkansas Sediment (0-5 cm), Expressed as mg/kg Soil.

Sam pling Interval Concentrati o n in Sediment (mg/kg)

Orthosulfamuron DOP U rea (S12) o-Desm ethyl Orthosulfamuron (S9) DBS Acid (S 1) 3 day s 0. 18 2 0. 04 2 ND 0. 06 1 7 day s 0. 05 5 0. 12 6 <0.005 0. 06 5 15 day s 0. 01 9 0. 14 1 <0. 0 0 5 ND 22 day s 0. 01 1 0. 08 5 <0.005 0. 05 3 1 m onth 0. 00 8 0. 06 2 <0.005 0. 03 1 a 2 m onths <0. 0 0 5 0. 04 9 ND ND Orthosulfamuron, S12 and S9: LOD = 0. 0006 mg/kg and LOQ = 0.005 mg/kg. S 1 : LOD = 0.008 mg/kg and LOQ = 0.02 mg/kg.
a S ingle r e pli c ate valu e (o ther rep lic ates <LOQ)



### Table B-6. Mean Concentration of Orthosul fa muron Residues in Arkansas Wate r(mg/L).

Sam pling Interval Concentrati o n in Water (mg/L)

Orthosulfamuron DOP U rea (S12) o-Desm ethyl Orthosulfamuron (S9) DBS Acid (S 1) 3 day s 0. 02 4 <0. 0 0 5 ND 0. 00 6 7 day s 0. 01 2 <0. 0 0 5 ND 0. 00 9 a 15 day s 0. 00 6 a<0. 0 0 5 ND 0. 01 1 a 2 2 d ays <0 .0 05 <0 .0 05 N D 0. 00 9 1 m onth <0. 0 0 5 <0. 0 0 5 <0. 0 0 5 0. 00 6 a 2 m onths <0. 0 0 5 <0. 0 0 5 ND <0. 0 0 5 Orthosulfamuron, S12 and S9: LOQ = 0.005 mg/L. S1: LOQ = 0

. 02 mg/L.
a M ean fromr e pl icat es with a

de t ect ion



### 82

### At the Calif ornia test site, orthosulfamuron dissipated in the soil and sedim e nt with fi rst-order half-lives of 2.3 days (r2 

### = 0.8678) and 4.3 days (r2 

### = 0.438), respectively. A half-life for orthosulfam uron in water could no t b e calcu lated because the chem ical was not detected in the water. The levels of orthosulfam uron and thre e degradation products in soil (0–15 cm depth) and sedim e nt are shown in Tables B-7 and B-8

.

Table B-7. Mean Concentration of Orthosul famuron Residues in California Soil (0–15 cm), Expressed as mg/kg Soil.

Days Posttreatment Average Residue in the 0–15 cm Soil Depth (m g/kg)

Orthosulfamuron DOP U rea (S12) o-Desm ethyl Orthosulfamuron (S9) DBS Acid (S 1) 0 0. 09 4 <0. 0 0 5 ND <0. 02 1 0. 09 5 0. 00 8 ND <0. 02 3 0. 03 1 a 0. 01 2 aND <0. 02 7 0. 01 3 0. 02 2 ND <0. 02 15 <0. 0 0 5 0. 01 9 ND ND 31 <0. 0 0 5 0. 01 7 b ND ND 62 ND 0. 01 0 ND ND 12 2 ND 0. 03 1 ND ND 19 4 <0. 0 0 5 0. 04 0 ND ND 28 4 – 0. 02 1 – – 37 2 – 0. 03 6 – – 46 4 – 0. 01 5 a– – 55 3 – 0. 02 4 – – Orthosulfamuron, S12, and S9: LOD = 0

. 0006 mg/kg and LOQ = 0.005 mg/kg. S1: LOD = 0.00 8 mg/kg and LO Q = 0

. 02 mg/kg.
a S ingle r e pli c ate valu e (o ther rep lic ates <LOQ) b Mean o f duplicate detects (w ith the third replicate <LOQ)


### Table B-8. Mean Concentration of Orthosulfa muron Residues in California Sediment (0­ 5 cm), Expressed as mg/kg Soil.

Sam pling Interval Concentrati o n in Sediment (mg/kg)

Orthosulfamuron DOP U rea (S12) o-Desm ethyl Orthosulfamuron (S9) DBS Acid (S 1) 3 day s 0. 06 2 0. 02 8 ND <0. 02 7 day s 0. 05 0 0. 10 0 ND <0. 02 15 day s 0. 00 7 a 0. 03 3 ND ND 1 m onth <0. 00 5 0. 02 3 b ND ND 2 m onths ND 0. 01 7 ND ND Orthosulfamuron, S12 and S9: LOD = 0. 0006 mg/kg and LOQ = 0.005 mg/kg. S 1 : LOD = 0.008 mg/kg and LOQ = 0.02 mg/kg.



### 83

### Table B-8. Mean Concentration of Orthosulfa muron Residues in California Sediment (0­ 5 cm), Expressed as mg/kg Soil.

Sam pling Interval Concentrati o n in Sediment (mg/kg)

Orthosulfamuron DOP U rea (S12) o-Desm ethyl Orthosulfamuron (S9) DBS Acid (S 1)

a S ingle r e pli c ate valu e (o ther rep lic ates <LOQ) b Mean o f duplicate detects (w ith the third replicate <LOQ) 

### The study is classified as supplem ental becau se the storag e stability data (from field spikes) could not demonstrate stabilityof the parent and transform ation products f o r the m aximum storage interval of test sample s (with the excep tio n of parent and S12 from the Arkansas water sam p les). Recoveries for S1 from Arkansas so il and sedim e nt and for orthosulfam uron, S1, and S12 from Ca lifornia soil and sedim e nt were low, indicating that the co m p ounds were not stable f o r the stor a g e inte rval. 165-4 Accumulation in Fish MRID 46588507 (Acceptable) The bioaccumulation of [ 14 

### C-5-pyrim idinyl]-labeled orthosul fam uron was studied in bluegill sunfish ( Lepomis macrochirus ) at nom i nal concentrations of 142 μg/L (low-dose) and 1420 μg/L (high-dos e) under flow-through cond itions. Fo llo wing the 14-day exposure period, fis h from each aquariumwere tran sferred to a flow-through system with untreated tap water for a 14-day depuration period. Calculated bioconcentration f actors (BCFs) in the lowdose experim e nts, based on the average amount of re sidual radioactivity in fish during the entire exposure period, were 0.29, 0.34, and 0.32 for edible tissues, non-ed ible tissues, and whole fish tissues, respectively. Lipid content in control fishsam ples was 11.3–11.8 m g/g in edible tissues, 20.0– 21.7 m g/g in non-edible tissues, and 16.7–17.7 m g /g in whole f i sh. Average lipid-BCF values ranged from 16–29. In the high dosage experim e nts, calculated BCFs we re 0.72, 1.14, and 0.97 for edible tissues, non-edible ti ssues, and whole fish, respectively. Averag e lipid-BCF values ranged from 52–68.

84

### Synonyms and Chemical Structures The synonym s, IUPAC nam e s, and chem ical structures of orthosulfam uron and its transform ation products are provided in Table B-9

.

Table B-9. Chemical S t ructures o f Or thosulfamuron and Degradation Products Detected in Submitted Envi ronmental Fate Studies. Name Structure Ort hos ul fam ur on S3 I R 58 78 1- (4 ,6

- di m etho xypyri m i di n-2

- y l )­ 3- [2 -( di m e thy l carbam o y l )ph e ny l s ul fa m oyl ] urea CA S # 2 134 64- 77 -8 N

O NH S O O

NH O

NH
N N O

O DBS aci d S1 I R 78 63 2- di m e thy l carbam o y lpheny l s u l fam i c acid O
N O
S O
OH HN

DBS am ide S2 2

- su lf m o ylam i n o- N,N-d i m e thylbenzam ide O
N O
S O

NH 2 HN

DB am ine S4 2-am i no- N, N- di m e thy l benzam i d e O

N H 2 N



### 85

### Table B-9. Chemical S t ructures o f Or thosulfamuron and Degradation Products Detected in Submitted Envi ronmental Fate Studies. Name Structure O- desm ethy l orth osul fam uro n S9 I R 81 81 1- (4

- hy dr o xy - 6-m ethoxy pyri m i di n2

- yl)- 3­ [2 -( di m e thy l carbam oy l )phe ny l s ul fam oy l ] urea NH O
NH O S O

NH N

O N N O

HO DOP urea S12 I R 78 25 N- (4 ,6 -di m ethoxy pyri m i di n2-yl)urea

N H O

H 2 N N

N O O

DOP am ine S13 4, 6- di m e thoxypyri m i di n-2-y l am i ne N
N

O O H 2 N

O- desm ethy l DOP ure a S15 N- (4 -hy dr o xy - 6 -m ethoxy pyri m i di n2-yl)urea

N H O

H 2 N N

N O OH



### 86

## APPENDIX C. Interim Ri ce Model Input/Output data.
1. Interim Rice Model (USEPA, 2002).
EEC = 10 9 

### x M T

### / [ V T

### + (m sed

### x K d 

### )] where, M T

### = total m ass of pesticide applied per area = 0.0772 kg a.i./ha V T

### = volume of paddy water, including water columnand pore water = 1.067 x 10 6 

### L/ha K d

### = m ean KOC 

### from ni ne soils tim es 2% soil organic carbon content = 359 L/kg OC 

### x 0.02 = 7.19 L/kg m se d

### = m a ss of top 1 cm of sedim e nt = 1.30 x 10 5 

### kg/ha 10 9 

### = μg/kg conversion f o r estim ate of ppb EEC = the dissolved concentration in water (μg a.i./L, ppb)
Exam ple calculation: EEC (μg a.i./L) = (10 9 

### μg/kg) x (0.0772 kg a.i./ha) / [1.067 x 10 6 

### L/ha + (1.30 x 10 5 

### kg/ha x 7.19 L/kg)] = 38.6 μg a.i./L (ppb)

2. Units conversion for semi-aquatic plant calculations: EEC (lbs a.i./A) = (38.6 μg a.i./L) x (1.067 x 10 6 

### L/ha) x (2.20 x 10 -9 

### lbs a.i./μg a. i.) x (0.405 ha/A) = 0.0367 lbs a.i./A

87

## APPENDIX D: Exampl e T-Rex Input and Output for Orthosulfamuron.

88

### 89

### T-Rex can be found at: http://www. epa.gov/oppefed1/mod els/terrestrial/trex_usersguide.htm 

## APPENDIX E: Exam ple Terrplant (v. 1.2.1) Input and Output for Orthosulfamuron.

90

### 91

## APPENDIX F: Ecological Effects Assessment.
II. Toxicityto Freshw ater Aquatic Animals

a. Freshw ater Fish, Acute Two freshwater fish toxicity studies using the technical grad e activ e ingr e d ient (TGAI) are required to establish the acute toxi city of orthosulfam uron to fish. The preferred test species are rainbow tro ut (a co ldwater fish) and bluegill s unf ish (a warmwater fish). Acceptable acute toxicity studies using orthosulfam uron TGAI have been submitted for rainbow trout (one study) and bluegill sunfish (one study). The results are summ arized in Table E-1

. The 96-hour LC 50 

### values reported in these static, acute t oxicity studies ex ceeded 122 mg a.i./L in rainbow tro ut (MRID 4 6219042; Acceptab l e) and 142 m g a.i./L in b l uegill sunfis h (MRID 46219043; Acceptable) indicating th at orthosulfamuron is practically nontoxic to freshw ater fish. The guidelin e (72-1) is f u lf illed. In addition to lethality endpoints, sublethal e ffects of acute orthosulfam uron TGAI exposure were assessed in studies in rainbow trout (MRID 46219042; Acceptable) and bluegill sunfish (MRID 46219043; Acceptable). No signs of sublethal toxicity were observed in either study. No studies assessing the acute toxi city of orthosulfam uron formulations degradates in fish were subm itted.

92

### Table E-1. Acute Toxicity of Technical Gr adeOrthosulfa muron (TGAI) to Fres hw ater Fish.

Species % a.i. LC 50 

### Comments Toxicity Category Identification Numbe r

(Study Classification) Rainbo w trout ( On co r hyn ch us mykiss ) 98 .5 6 96

- h LC 50 : >122 m g a.i./L 9 6 -hacut e tox i city test inj uv e n ile rainb o w trout un d e r static test co nd itio ns. Nomin a l co n c entration s : 0 (n eg ativ e contro l), 16, 26, 43, 72, and 120 m g a.i./L M ean m easure dc once n tr at i o ns: 0, 16, 26, 44, 74, and 122 m g a.i./L, respectively. Practically no nt o xi c MRI D 4 621 904 2 (Acce ptable )

No m o rtalities o r sub l eth al effects i nco ntr o l gr ou p or anytreatm e nt gr o ups
. 96 -h L C 50 : >1 22 m g a.i ./L (95 % C.I.: N/A; P r o b it slo p e: N/ A)

Blu e g ill sun f ish (Le pomis macr oc hi ru s ) 98 .5 6 96

- h LC 50 : >142 m g a.i./L NOAEC (m o rtality an dsub l et h al effects): 122 mg a.i./L LOAEC (m o rt ality an dsub l et h al effects): > 1 22 m g a.i. /L 9 6 -hacut e tox i city test inj uv e n ile b l u e g ill sun f ish un d e r static test co nd itio ns. Nomin a l co n c entration s : 0 (n eg ativ e contro l), 16, 26, 43, 72, and 120 m g a.i./L; mean m easured c once n trations: 0, 18, 34, 46, 84, and 142 m g a.i./L, respectively. Practically no nt o xi c MRI D 4 621 904 3 (Acce ptable )

No m o rtalities o r sub l eth al effects inth e con tro l gr oup o r any tr eatm e nt gr o u p s. 96 -h L C 50 : >1 42 m g a.i ./L (9 5% C

. I.: N/ A; Pr o b it slo p e : N/A )
NOAEC (m o rtality an dsub l et h al effects): 142 mg a.i./L LOAEC (m o rt ality an dsub l et h al effects): > 1 42 m g a.i./L 

### b. Freshw ater Fish, Chronic A freshwater fish early life-stag e tes t using the T GAI is required for ortho sulfam uron because end-use pro ducts cou l d contam inate surface wate r through d r ift or runoff events and m ay be transpo rted to water f r o mthe intend ed use site.

93

### One early life-stag e tox i city study w i th fathead m i nnow was subm itted (M RID 46578953; Acceptable). NOAEC and LOAEC values were based on dry we ight m easurem ents, the only endpoint affected. Study details and results are summ arized in Table E-2

. In addition to lethality, su blethal effects of orthosu l fam uron were assessed in the subm itted study (M RID 46578953; Acceptable). No signs of exposure-relate d subleth a l tox i city were observed

. The guideline (7 2-4[ a] ) is f u lf illed. No chronic toxicity studies of orthosulfam uron form ulations or degrad ates in freshwater fish were subm itted.
Table E-2. Chronic Toxicity of Techni cal Gra d e Orthosulfamuron (T GAI) to Marine/Es tuarine Fish.
Species % a.i. NOA E C Comments Identification Number (Study Classification) Fathead 98 .5 6 NO AEC : 3 3 -d ay early life-stag e tox i city test u s ing fertilized MRI D 4 657 895 3 m i nno w 6. 1 m g egg s / e m b ry os un de r fl ow -thr ou g ht e st c o n d i t i ons. (Acce ptable ) ( Pi me ph al es a.i./L No m in a l co ncentration s : 0 (n eg ativ e co nt ro l ) , 0

. 75 , pro m elas ) (drywei ght) 1. 5, 3. 0, 6 .0 , an d 1 2 m g a.i ./L .; m ean m easur ed conce ntrat i o ns: 0, 0 .7 6 , 1 .5 , 3. 2, 6. 1, an d 1 3 m g a.i./L, re specti v ely.
En dp oi nt s m o n i t o red: em bry o survi v al , l ar v a l surv iv al, term i n al leng th , dry weigh t , wet weig h t , an d clin ical sign s o f tox i city.
D ay 33 (2 8 d ays p o st- h atch ), dry w e igh ts aver ag ed 1 1 .7 m g f o r

the con tro l gr oup, 11 .4– 1 2

. 5 m g fo r t

h e 0. 76 thro u g h6

. 1 m g a.i

. /L gr o ups , an d 10 .2 m g for th e 13 m g a.i./L group
. No oth er treatm en t -related effects were observe d. NO AEC (dr y w e ight) : 6. 1 m g a.i./L LOAEC (dry weigh t ): 1 3 m g a.i./L (drywei ght)



### c. Freshw ater Invertebrates, Acute A freshwater aquatic invertebrate toxicity study using the TGAI is required to establish the toxicity of orthosulfam uron to freshwater inverteb rates. Th e preferred test species is the water flea (Daphnia magna ). One acute toxicity study usi ng orthosulfam uron TGAI has been subm itted for water flea (MRID 46219044; Accept able). Stu dy details an d results are summarized in Table E-3

. An acute toxicity value (48-hour E C 50 

### ) greater than 97.3 mg a.i./L (the highest concentratio n tested) was reported for Daphnia magna (MRID 46219044; Acceptable). Based on this resu lt, o rthosulfam uron TGAI is catego r ized as not m o re than slightly toxic to freshwater invertebrates on an acute basis. The study did not distinguish between m o rtality and imm obility; therefore, the EC 50 

### value of >97.3 m g a.i./L is used as a

94

### surrogate value for lethality to evaluate acute toxic exposure of freshwater invertebrates to orthosulfam uron. The guideline (72-2) is fulfilled. A 96-hour acute toxicity study with crayfish ( Procambarus clarkia ) was subm itted ( MRID 46578955; Supplem ental). Study details and results are summarized in Table E-3

. There were no deaths or sublethal ef fects at any of the concentrations tested. The 96-hour LC 50 

### and the NOAE C for mortality and sublethal effects were >129 and 129 m g a. i./L, respectively, indicating that orthosulfam uron wa s practica lly nontoxic to the crayfish on anacute basis. Although this study is scientifically so und it is classified as Sup p lem e ntal becau se crayfish are no t a U.S. EPArecomm ended species for toxicityte sting withf r eshwater inv e rtebrates, and guidelines do not exist for this species. The resu lts of this study, however, are useful for risk assessm ent purposes. No acute toxicity studies of orthosulfam uron formulations or degradates in freshwater invertebrates were submitted.
Table E-3. Acute Toxicity of Technical Gr adeOrthosulfa muron (TGAI) to Fres hw ater Invertebrates.

Species % a.i. EC 50

### /LC 50 

### Comments Toxicity Category Identification Numbe r

(Study Classification) Water flea 98 .5 4 48

- h EC 50 : (Da phn ia >9 7.3 m g m agn a ) a.i./L (m o rtality an d i mm o b ility) 48-h ac ute toxicity in neonate d a

phn id s und er static test co nd itio n s
. No m in a l co ncentration s : 0 (n eg ativ e cont rol ) 6

. 2 5 , 12 .5 , 25 , 50 , an d 1 0 0 m g a.i./L; m e anm easured co n c en tration s for co n t ro l and two h i gh est treatm e nt lev e ls (th e on ly lev els an alytically v erified) were <1 .7 , 47 .0 , and 97 .3 m g a. i. /L.
4 8 -hm o rtality: 20 % i n 9 7 .3 mg a.i./L g r oup. No m o rtality inco nt ro l or othe r tr eatm e nt g r o u p s. 48 -h E C 50 : >9 7. 3 m g a.i ./L 95 % C. I.: N/A; Pr obit sl ope: N/A (fo r m o rtality an d imm o b ili ty)
NO AEC: 47 .0 m g a.i./L (fo r m o rtality an d imm o b ili ty)
LOAEC: 97 .3 m g a.i./L (fo r m o rtality an d imm o b ili ty) Slig h tly MRI D 4 621 904 4 t oxi c (Acce ptable )



### 95

### Table E-3. Acute Toxicity of Technical Gr adeOrthosulfa muron (TGAI) to Fres hw ater Invertebrates.

Species % a.i. EC 50

### /LC 50 

### Comments Toxicity Category Identification Numbe r

(Study Classification) Crayfish , ( Pr oca m barus clarkia ) 98 .5 6 96

- h LC 50 , EC 50 >129 m g a.i./L 96

- hac ut e t o xi ci tyst udyi n j uveni l e crayfish under static test conditions. No m i n al co ncentration s : 7.5, 1 5 , 3 0 , Practically no nt o xi c MRI D 4 657 895 5 (Su p p lem e ntal) (fo r m o rtality 60, an d 120 mg a.i./L; m ean measured and s ubl ethal conce ntr at i o ns: 8. 2, 1 6 , 3 2 , 6 4 , an d effects) 1 2 9 m g a.i./L, resp ectiv ely. End p o i nt s assessed : m o rtalityand sublet hal effects.
No m o rtalities o r sub l eth al effects w e r e ob serv ed dur ing t h e study at any treatm ent lev el.
Th is st u dyis scientifically so un d , but it is classified as Supplem ental because gui delines do not e x ist for this species

. 96 -h L C 50 : >1 29 m g a.i ./L 95 % C. I.: N/A; Pr obit sl ope: N/A
EC 50 : >1 29 m g a.i./L (fo r sub l eth al effects)
NO AEC: 12 9 m g a.i./L (fo r m o rtality an d sub l eth a l effects) 

### d. Freshw ater Invertebrate, Chronic A freshwater aquatic inv e rteb rate life-cycle tes t using the TGAI is required for orthosulfam uron because the end-use pro duct m ay be transpo rted to water fro mthe intend ed use site. One life-cycle toxicity study with Daphnia magna (MRID 46578956; Acceptab l e) was subm itted. Study details and resu lts are summ arized in Table E-4

. NOAEC and LOAEC values of 6.5 and 14 m g a.i./L, respectively, were establis hed based on reductions in m e an total length. In addition, first generation survival was reduced at the highest dose tested. Reproduction and dry weight were not af f ected atany of the doses tested.

. The guideline ( 72-4[ b] ) is f u lf illed. No life-cycle toxicity studies of orthosulfam uron form ulations or degradates in freshw ater aquatic inve rtebr ate s were subm itted

.

96

### Table E-4. Chronic Toxicity of Technical Gra d e Orthosulfamuron (T GAI) to Fre shw ater Invertebrates.

Species % a.i. NOA E C Comments Identification Numbe r

(Study Classification) Cladoceran (Da phn ia 98 .5 6 NO AEC : 6. 5 m g a.i./L. 21

- d aychro ni c t oxi ci tyi n D a ph ni a m a gn a n e onat e s un d e r static ren e wal con d ition s
. No m i n a l MRI D 4 657 895 6 m agn a ) (to t al leng th) conce ntr at i o ns: 0 ( n egat i v e co ntr o l ) , 6. 3, 1 3 , 25 , 50 , (Acce ptable ) and 100 m g /L.; m ean m easure dc once ntrations: < 3 .00 (LO Q, co ntr o l ) , 6 .5 , 14 , 26 , 5 2 , an d 10 5 m g a.i ./L , respectively.
En dp oi nt s a sse ssed: fi rst gene rat i o n sur v i v al , rep ro d u ct i o n , t o t a l l e ngt h, drywei g ht , an d s u bl ethal si gns o f t oxi ci ty . End p o i nt s affected : to tal length , dry weigh t , first g e n e rationsurv iv al. Mo st sen s itiv e en dpo int: to tal l e ngth

. Tot a l Le ngt h ( g r o wt h): NO AE C : 6. 5 mg a.i . /L LOAEC: 14 m g a.i./L DryWeig ht ( g ro wth ) : LO AEC: >105 m g a.i./L NO AEC: 10 5 m g a.i./L First g e n e rationsurv iv al: EC 50 : >1 05 m g a.i./L LOAEC: 105 m g a.i./L NO AEC: 52 m g a.i./L
Neo n at e pr o du c t i on (re pr o duc t i on): EC 50 : >1 05 m g a.i./L NO AEC: 10 5 m g a.i./L LO AEC: >105 m g a.i./L



### e. Freshw ater Benthic Organisms Studies in benthic organism s are not guideline requirem e nts. No toxicity studies of orthosulfam uron TGAI, form ulations, or degrad ates in freshw ater benthic organism s were subm itted.
III. Toxicity to Estuarine and Marine Animals

97

### a. Estuarine and Marine Fish, Acute Acute toxicity testing with estuar ine/m arine fish using the T GAI is required for orthosulfam uron. The preferred test species is the sheepshead m i nnow. One acute toxicity study in estuarine/m arine fish was subm itted for sheepshead m i nnow ( MRID 46578951; Accep table). Study details and results are summ arized in Table E-5

. The subm itted study rep o rted an LC 50 

### >123 m g a .i./L, indicating that orthosulfam uron was practically nontoxic to estuarine/m arine fish on an acute basis (MRID 46578951; Acceptable). No sublethal effects were observed in sheep shead m i nnow exposed up to 123 m g a.i. orthosulf am uron/L. The guideline (7 2-3[ a] ) is f u lf illed. No acute toxicity studies of orthosulfam uron formulations or degrad ates in estuarine/m arine fish were subm itted.
Table E-5. Acute Toxicity of Techni cal GradeOrthosulfa muron (TGAI) to Estuarine/Marine Fis h .

Species % a.i. LC 50 

### Comments Toxicity Category Identification Numbe r

(Study Classification) Shee ps head m i nno w ( Cyp r i n odo n variegates ) 98 .5 6 96

- h LC 50 : >123 m g a.i./L 9 6 -hacut e tox i city test inj uv e n ile shee pshea dm i nn o w un de r st at i c t e st co nd itio ns. Nomin a l co n c entratio n s : cont rol , 1 6 , 2 6 , 4 3 , 7 2 , an d 12 0 m g a.i./L; m ean measure dc o ncentrations: 16, 27, 45, 75, and 123 m g a.i./L, resp ectiv ely. Co n tro l co n c entratio n s were n o t re p o rt ed. Practically no nt o xi c MRI D 4 657 895 1 (Acce ptable )

End p o i nt s assessed : m o rtalityand sublet hal effects.
En dp oi nt s a ffe ct ed: n one 96 -h L C 50 : >1 23 m g a.i ./L 95 % C. I.: N/A; Pr obit sl ope: N/A
Su

bl ethal ef fec t s: EC 50 : >1 23 m g a.i./L NO AEC: 12 3 m g a.i./L 

### b. Estuarine and Marine Fish, Chronic No lif e cycle toxic ity tes twith es tuar ine/ m ari ne fish with orthosulfam uron TGAI, formulations, or degrad ate s were submitted. The gu ideline (72

- 5) is no t f u lf illed.

98

### c. Estuarin e and Marine Aquatic Invertebrates, Acute Acute toxicity tes ting with estu arin e/m arine invertebrates using the TGAI is required f or orthosulfam uron. The preferred test species are east ern oyster (Guideline 72-3[b]) and mysid shrim p (Guideline 72-3[c]).
One acute to xicity study using ortho s ulfam uron TGAI has been subm itted for Eastern oyster; study details and results are summ arized in Table E-6

. No effect on shell deposition was observed, yielding a 96-hour EC 50 

### >97 m g a.i./L (MRID 46578957; Acceptable). The study did not report any other sublethal eff ects. An acute toxicity study using orthosulfam uron TGAI was subm itted f o r the my sid shrim p ; stud y details and results ar e s umm arized in Table E-6

. The study reported an LC 50 

### >122 m g a.i./L (MRID 46578952; Accep tab l e). No sublethal effects were observed in this study. The EC 50 

### valu e of >97 m g a.i./L will be us ed to asses s ac ute r i sk to estuar ine /m arine m o llusk s and the LC 50 

### value of >122 m g a.i./L to assess acute risk to estuar ine /m arine shrim p. The guideline (72-3) is f u lf illed. No acute toxicity studies of orthosulfam uron formulations or de gradates in estuarine/m arine invertebrates were submitted.
Table E-6. Acute Toxicity of Techni cal GradeOrthosulfa muron (TGAI) to Estuarine/Marine Inv ertebra tes.

Species % a.i. EC 50

### /LC 50 

### Comments Toxicity Category Identification Numbe r

(Study Classification) Eastern Oyster 98 .5 6% 96

- h EC 50 : ( Cra s so trea >97 m g virg in ica ) a.i./L (base do n sh ell gr owt h)

Saltwater 98 .5 6 96

- h LC 50 : mys i d >122 m g ( Americamysis a.i./L ba hi a ; fo rm erly know n as Mysidopsis 9 6 -hacut e tox i city test inth e Eastern o y ster un d e r fl o w -throug h con d ition s
. No m in a l co ncentration s : 0 (n eg ativ e cont rol ) , 6. 3, 1 3 , 2 5 , 5 0 , an d 10 0 m g /L ; mean m easured c once n trations were Slig h tly t oxi c MRI D 4 657 895 7 (Acce ptable )

<3 .0 0 ( < LOQ , co n t r o l), 6

. 2 , 13 , 24 , 49 , and 97 m g a.i./L, re spectively

. End p o i n t s assessed : m o rtalityandsh ell gr owt h

. No m o rtality an d no exp o sure-related changes in s h el l growth. Sh ell d e po sition : 96 -h E C 50 : >9 7 m g a.i ./L
NO AEC: 97 m g a.i./L 9 6 -hacut e tox i city test insaltwater my si d un der st at i c con d i t i ons
. N o m i nal co n c entration s : 0 (n eg ativ e contro l), 16 , 26, 43, 72, an d 120 m g a.i./L; m ean measured conc entrations were <5.0 Practically no nt o xi c MRI D 4 657 895 2 (Acce ptable )
(<LO Q; c ont ro l ), 16 , 26 , 43 , 7 3 , an d 12 2 m g a.i./L, respectiv ely.



### 99

### Table E-6. Acute Toxicity of Techni cal GradeOrthosulfa muron (TGAI) to Estuarine/Marine Inv ertebra tes.

Species % a.i. EC 50

### /LC 50 

### Comments Toxicity Category Identification Numbe r

(Study Classification) ba hi a ) 9 6 -hm o rtality was 5 , 5 , an d 10 % i nth e 4 3 , 7 3 , an d 122 m g a.i./L treatm ent gr o ups , r e spect i v el y . N o su bl ethal effects were observe d.
96 -h L C 50 : >1 22 m g a.i ./L 95 % C. I.: N/A; Pr ob it slop e: N/A LOAEC: 43 m g a.i./L (m o rtality) NO AEC: 26 m g a.i./L (m o rtality) 

### d. Estuarine and Marine Inverteb rates, Chro nic The estuar in e/m arine aq uatic invert e b rate lif e-cy cle test using the TGAI of orthosulfam uron is required. T he preferred test species is the mysid shrim p. One life-cycle tox i city study in the my sid shrim p was subm itted; the studydetails and results are summarized in Table E-7

. NOAE C and LOAEC values of 27 and >27 mg a.i. orthosulfam uron/L, respectively, were establishe d for mysid shrim p based on the absence of an effect on m o rtality, reproducti on, or growth after 29 days (MRID 46578954; Acceptable). The NOAEC of 27 m g a.i./L will be us ed estim ate and characterize chro nic risk to estuarine/m arine invertebrates. The guid e line (72- 4[ c]) is fulfilled although the study is classified as s upplem ental since reproduction of the control treatm e nt was marginally adequate (75% of control produce 8 or m ore offs pring in two broods). No chronic toxicity studies of orthosulfam uron form ulations or degradates in estuarine/m arine invertebrates were submitted.
Table E-7. Chronic Toxicity of Techni cal Gra d e Orthosulfamuron (T GAI) to Estuarine/Marine Inv ertebra tes.

Species % a.i. NOA E C Comments Identification Numbe r

(Study Classification) Saltwater m y sid 98 .5 6 NO AEC: 27 ( Americamysis m g a.i./L ba hi a ; fo rm erly (m o rtality, know n as gr owt h, Mysidopsis r e pr odu ctio n, ba hi a ) clin ical sig n s ) 29

- d ay , c hr oni c t oxi ci tyt e st i nm y si d shri m p MRI D n e on ates un d e r flow-t hr ou ghco nd itio ns. Nomin a l 4 657 895 4 conce ntrat i o ns: 0 ( n egat i v e co ntr o l ), 1. 7 5 , 3. 25 , 6. 5, (Su p p lem e ntal) 13, an d 26 m g /L; m ean m easured conce ntrations were <0 .5 , L O Q, ne gat i v e c o ntr o l , 1. 88 , 3. 5 6 , 6. 6, 14, an d 27 m g a.i./L, re specti v ely.



### 100

### Table E-7. Chronic Toxicity of Techni cal Gra d e Orthosulfamuron (T GAI) to Estuarine/Marine Inv ertebra tes.

Species % a.i. NOA E C Comments Identification Numbe r

(Study Classification) En dp oi nt s a sse ssed: fi rst gene rat i o n sur v i v al , r e pr odu ctio n, bo dylen g t h , dry w e igh t, andcl in ical si gns
. N o eff ects o nsurv iv al, gr ow t h , r e p r o d u c tion, or clin ical sig n s were ob serv ed

. Mo rtality, repro d u c tion , growth , clin ical signs: LOAEC: >27 m g a.i./L NO AEC : 27 mg a.i./L



### e. Aquatic Field Studies No aquatic f i eld s tudie s were subm itted.
IV. Toxicity to Plants Inha biting Aquatic Environments Acute toxicity testing with plants inhabiting a quatic environm ents using the form ulated product is required f or orthosulfam uron. El even acute toxicity studies using orthosulfam uron form ulations (typical end

- use product, TEP) have been subm itted for freshw ater algae, saltwater algae, and aquatic vascular plants

. All studies were classified as Acceptable or Supplem e ntal. Study details and results are summ arized in Table E-8

. Studies with algae yielded EC 50 

### values ranging from 0.16 m g form ulation/L (equivalent to 0.08 m g a.i./L) for reductions in biom ass in the m arine diatom Skeletonema costatum (MRID 46578931) to >108 m g form ulation/L (equivalent to >54 m g a.i ./L ) in the f r eshwater d i at om Navicula pelliculosa (MRID 46578932; Acceptable), indicating that orthosulf am uron is sli ghtly to hig h ly toxic to algae. Resu lts of 14-day studies in duckw eed (a fres hwater vascular plant) yield EC 50 

### values ranging from 1.4 μg form ulation/L (equivalent to 0.7 μg a.i./L ) for decreased from num ber (MRID 46578939; Acceptable) to 1.5 μg formulati on/L (equivalent to 0.75 μg a.i. /L) for decreased frond num b er (MRID 46578940; Acceptable), indicating that orthosulfam uron is very highly toxic to freshwater vascular plants. Based on these resu lts, aquatic m a crophytes an d m arine algae appear much m o re sensitive thanf r eshw ater algae to orthosulfam uron. The lowest EC 50 

### values will be us ed to asses s acute r i sks to aq uatic p l ants: EC 50 

### = 1.6 mg form ulation/L (equivalent to 0.8 m g a.i./L) for decreased biomass in Navic ula pellicu l o s a (MRID 46578935; Supplem ental) for freshwater algae; E C 50 

### = 0.16 mg form ulation/L (equivalent to 0.08 mg a.i./L) for decreased biom ass in Skeletonema costatumfor m arine algae (MRID 46578931; Supplem ental); EC 50 

### = 1 .4 μg f o rm ulation/ L (equ ivalent to 0.7 μg a.i./L) f or decreased biom ass in Lemna gibba (MRID 46578939; Acceptable) for freshwater vascu l ar p l ants. The guideline requirem e nt for Tier II growth and reproduction studies (Guideline 123-2) in aquatic plants is f u lf illed.

101

### Table E-8. Acute Toxicity (T ier II) of Or thos ulfamuron formula t ion(TEP) to Plants Inhabiting Aquatic Environments.

Species % a.i. EC 50 

### Comments Toxicity Category Identification Numbe r

(Study Classification) Freshwater Algae Fres hwate r gree n al gae ( Sel e nast ru m cap r i c or nutum ) 49 .9 6 Cell density: EC 50 : 6

. 2 m g fo rm ul at i on/L (3.1 m g a.i./L)
Mo st sensitiv e en dpo in ts: cell d e nsity 96

- hac ut e t o xi ci tyst udyo f I R 58 78 50W G ( f orm u latio n ) i ng r ee n al gae un de r st at i c co nd itio ns. Nomin a l conce ntrat i o ns: 1. 9, 3 .8 , 7. 5, 1 5 , an d 30 m g /L; m ean measured conc entration s : 1

. 9 , 3. 7, 7. 4, 1 5 , an d 30 m g /L , respectively. Endpoints a sse ssed: cell d e nsity, b i o m ass, an d gr ow t h rate. Cell density: EC 50 : 6. 2 m g f o rmul a ti o n/L (3.1 mg a.i./L) ; 9 5 % C.I.: 5. 3– 7. 2 m g f or

m

ul at i on/L (2.6–3 .6 m g a.i./L) EC 05 : 1. 1 m g f o rmul a ti o n/L (0 .5 5 m g a.i . /L ) ; 95 % C

. I.: 0. 78

– 1

. 6 m g f o rm ul at i on/L ( 0 .39– 0.80 m g a.i./L) NO AEC: < 1

. 9 m g fo rm ulation/L (<0

. 9 5 m g a.i./L) Pr ob it slop e: 2

. 2 0 ±0 .1 40 Growth r a te : EC 50 : >30 m g f o rm ul at i on/L (>15 m g a.i./L); 9 5 % C.I.: N/A EC 05 : 3.7 m g f o rm ul at i on/L (1 .8 m g a.i./L); 9 5 % C. I.: 3. 0–4. 6 m g f or

m

ul at i on/L (1.5–2 .3 m g a.i./L) NO AEC: 1. 9 m g fo rm ulation/L (0 .9 5 m g a.i./L ) Pr ob it slop e: 1

. 6 3 ±0 .0 859
B i omass : EC 50 : 6.6 m g f o rm ul at i on/L (3 .3 m g a.i./L); 9 5 % C. I.: 5. 7– 7. 8 m g f or

m

ul at i on/L (2.8–3 .9 m g a.i./L) EC 05 : 1.1 m g f o rm ul at i on/L Mo d e rately MRI D 4 657 893 1 t oxi c (Acce ptable )



### 102

### Table E-8. Acute Toxicity (T ier II) of Or thos ulfamuron formula t ion(TEP) to Plants Inhabiting Aquatic Environments.

Species % a.i. EC 50 

### Comments Toxicity Category Identification Numbe r

(Study Classification)

Fres hwat e r gre e n alga ( Sel e n a st ru m cap r i c or nutum ) 49 .9 6 B i omass : EC 50 : 2

. 9 m g fo rm ul at i on/L (1.4 m g a.i./L)
Mo st sensitiv e en dpo ints: bi om ass (0 .5 5 m g a.i./L ); 9 5 % C

. I.: 0. 74

– 1

. 6 m g f o rm ul at i on/L ( 0 .37– 0.80 m g a.i./L) NO AEC: < 1

. 9 m g fo rm ulation/L (<0

. 9 5 m g a.i./L) Pr ob it slop e: 2

. 0 8 ±0 .1 35

. Mo st sensitiv e en dpo in ts: cell d e nsity 96

- hac ut e t o xi ci tyst udyo f I R 58 78 50W G ( f orm u latio n ) i ng r ee n al gae un de r st at i c co nd itio ns. Nomin a l conce ntr at i o ns: 0. 1 2 , 0. 2 6 , 0. 58 , 1. 3, 2. 8, 6. 2, 1 4, an d 30 m g /L; mean measure d co n c entration s were 0.13 , 0. 27 , 0. 60 , 1. 3, 2. 8, 6

. 3 , 14 , and 31 m g /L, respectively. Endpoints a sse ssed: cell d e nsity, b i o m ass, an d gr ow t h rate. Si gni fi cant i nh i bi t i on of al l param e ters occ ur r ed in t h e adj uvant c o ntr o l

. Th is tox i city stu dy do es no t satisfy th e g u i delin e requirem ent be cause t h ere was si g n i ficant inh ib itio n in th e ad j uvant c o ntr o l

. T hus, th ere is un certain ty associated withth e effect s of th e adj uvant

. B i omass : EC 50 : 2. 9 m g f o rmul a ti o n/L (1.4 mg a.i./L) ; 9 5 % C.I.: 2. 3– 3. 8 m g/L ( 1. 1– 1. 9 m g a.i./L) EC 05 : 0. 17 m g form ulation/L (0. 0 8 mg a . i./L) ; 9 5 % C.I

. : 0

. 0 95– 0.32 m g form ul at i on/L ( 0

. 0 47 – 0. 16 m g a.i

. /L ) Mo d e rately MRI D 4 657 893 4 t oxi c (Su p p lem e ntal)



### 103

### Table E-8. Acute Toxicity (T ier II) of Or thos ulfamuron formula t ion(TEP) to Plants Inhabiting Aquatic Environments.

Species % a.i. EC 50 

### Comments Toxicity Category Identification Numbe r

(Study Classification)

Fres hwat e r gre e n 49 .8 0 Cell density: algae EC 50 : 7

. 0 m g ( Pse u dokirche riell fo rm ul at i on/L a su bcap ita ta ) (3.5 m g a.i./L) ( f

o rm e r l y known as Sel e nast ru m Mo st sensitiv e cap r i c or nutum ) en dpo in ts: cell d e nsity NO AEC: 0. 27 m g fo rm ulation/L (0 .1 3 m g a.i./L ) Pr ob it slop e: 1

. 3 5 ±0 .0 936 Cell density: EC 50 : 3.1 m g f o rm ul at i on/L (1 .5 m g a.i./L); 9 5 % C. I.: 2. 1–4. 4 m g f or

m

ul at i on/L (1.0–2 .2 m g a.i./L) EC 05 : 0.1 7 m g fo rm ul at i on/L (0 .0 8 m g a.i./L ); 9 5 % C

. I.: 0. 07 2

– 0

. 4 1 m g f o rm ul at i on/L ( 0 .036 –0 .20 mg a.i./L) NO AEC: < 0

. 1 3 m g fo rm ulation/L (<0

. 0 6 m g a.i./L) Pr ob it slop e: 1

. 3 2 ±0 .1 29 Growth r a te : EC 50 : 30 m g f o rm ul at i on/L (1 5 m g a.i./L); 95 % C. I.: 26 – 34 m g fo rm ul at i on/L ( 1 3– 1 7 m g a.i./L) EC 05 : 3.1 m g f o rm ul at i on/L (1 .5 m g a.i./L); 9 5 % C. I.: 2. 0–4. 9 m g f or

m

ul at i on/L (1.0–2 .4 m g a.i./L) NO AEC: 0. 6 m g fo rm ulation/L (0 .3 m g a.i./L) Pr ob it slop e: 1

. 6 7 ±0 .1 77
Mo st sensitiv e en dpo in ts: bi om ass 72

- hac ut e t o xi ci tyst udyo f I R 58 78 50W G ( f orm u latio n ) i ng r ee n al gae un de r st at i c co nd itio ns. Nomin a l conce ntr at i o ns: 0. 2 8 , 0. 6 2 , 1. 4, 3. 0, 6

. 8 , and 1 5 m g/L ; mean m easured conce ntr at i o ns: 0. 2 7 , 0. 5 7 , 1. 3, 2. 9, 6

. 4 , an d 1 5 m g /L , respectively. Endpoints a sse ssed: cell d e nsity, b i o m ass, an d gr ow t h rate. Mo d e rately MRI D 4 657 895 9 t oxi c (Acce ptable )



### 104

### Table E-8. Acute Toxicity (T ier II) of Or thos ulfamuron formula t ion(TEP) to Plants Inhabiting Aquatic Environments.

Species % a.i. EC 50 

### Comments Toxicity Category Identification Numbe r

(Study Classification)

Fres hwate r algae 49.96 Cell density: Th e st u dyis scientifically so und b ut do es no t satisf yth e g u i d e lin e requ i r em ent; th is st

udywas c o n duct e d fo r 72 h our s o n l y. Cell density: EC 50 : 7. 0 m g f o rmul a ti o n/L (3.5 mg a.i./L) ; 9 5 % C.I.: 4. 9– 9. 8 m g f or

m

ul at i on/L (2.4–4 .9 m g a.i./L) EC 05 : 1. 3 m g f o rmul a ti o n/L (0 .6 5 m g a.i . /L ) ; 95 % C

. I.: 0. 49

– 3

. 7 m g f o rm ul at i on/L ( 0 .24– 1.8 m g a.i./L) NO AEC: 0. 57 m g fo rm ulation/L (0 .2 8 m g a.i./L ) Pr ob it slop e: 2

. 3 0 ±0 .5 48 Growth r a te : EC 50 : >15 m g f o rm ul at i on/L ( >7.5 m g a.i./L) ; 95 % C

. I

. : N/A EC 05 : 3.5 m g f o rm ul at i on/L (1 .7 m g a.i./L); 9 5 % C. I.: 2. 1– 5. 6 m g f or

m

ul at i on/L (1.0–2 .8 m g a.i./L) NO AEC: 2. 9 m g fo rm ulation/L (1 .4 m g a.i./L) Pr ob it slop e: 1

. 7 8 ±0 .2 99
B i omass : EC 50 : 8.0 m g f o rm ul at i on/L (4 .0 m g a.i./L); 9 5 % C. I.: 5. 9– 1 1 m g f or

m

ul at i on/L (3.0–5 .5 m g a.i./L) EC 05 : 1.5 m g f o rm ul at i on/L (0 .7 5 m g a.i./L ); 9 5 % C

. I.: 0. 60

– 3

. 9 m g f o rm ul at i on/L (0.3–1 .9 m g a.i./L) NO AEC: 0. 57 m g fo rm ulation/L (0 .2 8 m g a.i./L ) Pr ob it slop e: 2

. 2 9 ±0 .5 23
Mo st sensitiv e en dpo in ts: cell d e nsity 96

- hac ut e t o xi ci tyst udyo f



### 105 M ode rat e l y M RID 46 5 7 8 9 3 7

### Table E-8. Acute Toxicity (T ier II) of Or thos ulfamuron formula t ion(TEP) to Plants Inhabiting Aquatic Environments.

Species % a.i. EC 50 

### Comments Toxicity Category Identification Numbe r

(Study Classification) ( Anab a e na flo s a qua e ) EC 50 : 3

. 8 m g fo rm ul at i on/L (1.9 m g a.i./L) I R 58 78 50W G ( f orm u latio n ) in algae under static co nd itio ns. Nomin a l conce ntrat i o ns: 0. 0 9 1 , 0. 20 , Mo st sensitiv e en dpo in ts: cell d e nsity 0. 45 , 1. 0, 2. 2, 5. 0, an d 11 m g /L; mean measure d conce ntrat i o ns: 0. 0 8 2 , 0. 19 , 0. 43 , 0. 96 , 2. 2, 4. 6, an d 1 0 m g /L, resp ectiv ely. Endpoints a sse ssed: cell d e nsity, b i o m ass, an d gr ow t h rate.
En larg ed cells were ob serv ed inth e 10 m g /L treatm ent g r oup. Cell density: EC 50 : 3. 8 m g f o rmul a ti o n/L (1.9 mg a.i./L) ; 9 5 % C.I.: 2. 5– 5. 6 m g f or

m

ul at i on/L (1.2–2 .8 m g a.i./L) EC 05 : 1. 0 m g f o rmul a ti o n/L (0 .5 0 m g a.i . /L ) ; 95 % C

. I.: 0. 37

–2

. 8 m g f o rm ul at i on/L ( 0 .18– 1.4 m g a.i./L) NO AEC: 2. 2 m g fo rm ulation/L (1 .1 m g a.i./L) Pr ob it slop e: 2

. 8 9 ±0 .7 50 Growth r a te : EC 50 : 4.7 m g f o rm ul at i on/L (2 .3 m g a.i./L); 9 5 % C. I.: 3. 7– 6. 0 m g f or

m

ul at i on/L (1.8–3 .0 m g a.i./L) EC 05 : 1.1 m g f o rm ul at i on/L (0 .5 0 m g a.i./L ); 9 5 % C

. I.: 0. 53

–2

. 1 m g f o rm ul at i on/L ( 0 .26– 1.0 m g a.i./L) NO AEC: 2. 2 m g fo rm ulation/L (1 .1 m g a.i./L) Pr ob it slop e: 2

. 5 5 ±0 .4 44
B i omass : EC 50 : >10 m g f o rm ul at i on/L ( >5.0 m g a.i./L) ; 95 % C

. I

. : N/A



### 106 toxic (Acce ptable )

### Table E-8. Acute Toxicity (T ier II) of Or thos ulfamuron formula t ion(TEP) to Plants Inhabiting Aquatic Environments.

Species % a.i. EC 50 

### Comments Toxicity Category Identification Numbe r

(Study Classification) EC 05 : 1.8 m g f o rm ul at i on/L (0 .9 0 m g a.i./L ); 9 5 % C

. I.: 0. 91

– 3

. 5 m g f o rm ul at i on/L ( 0 .45– 1.7 m g a.i./L) NO AEC: 2. 2 m g fo rm ulation/L (1 .1 m g a.i./L) Pr ob it slop e: 1

. 8 9 ±0 .3 77
Mo st sensitiv e en dpo in ts: cell d e nsity Fres hwate r algae 49 .9 6 Cell density: 96

- hac ut e t o xi ci tyst udyo f Mo d e rately MRI D 4 657 893 8 ( Anab a e na flo s - EC 50 : 4

. 7 m g I R 58 78 50W G ( f orm u latio n ) t oxi c (Acce ptable ) a qua e ) fo rm ul at i on/L in algae under static (2.3 m g a.i./L) co nd itio ns. Nomin a l conce ntrat i o ns of 0 .0 9 1 , 0. 2 0 , B i omass : 0. 45 , 1. 0, 2. 2, 5. 0, an d 11 EC 50 : 4

. 7 m g m g /L; mean measure d fo rm ul at i on/L conce ntrat i o ns: 0. 0 8 9 , 0. 20 , (2.3 m g a.i./L) 0. 45 , 0. 99 , 2. 2, 4. 9, an d 1 1 m g /L, resp ectiv ely. Mo st sensitiv e en dpo in ts: cell Endpoints a sse ssed: cell d e nsity an d d e nsity, b i o m ass, an d gr ow t h bi om ass rate. C e l l densi tyan d bi om ass were equ ally sen s itiv e. En larg ed cells were ob serv ed inth e 11 m g /L treatm ent g r oup. Cell density: EC 50 : 4. 7 m g f o rmul a ti o n/L (2.3 mg a.i./L) ; 9 5 % C.I.: 3. 5– 6. 5 m g f or

m

ul at i on/L (1.7–3 .2 m g a.i./L) EC 05 : 1. 8 m g f o rmul a ti o n/L (0 .9 0 m g a.i . /L ) ; 95 % C

. I.: 0. 87

– 3

. 7 m g f o rm ul at i on/L ( 0 .43– 1.8 m g a.i./L) NO AEC: 2. 2 m g fo rm ulation/L (1 .1 m g a.i./L) Pr ob it slop e: 3

. 9 2 ±0 .9 54
B i omass : EC 50 : 4.7 m g f o rm ul at i on/L (2 .3 m g a.i./L); 9 5 % C. I.:



### 107

### Table E-8. Acute Toxicity (T ier II) of Or thos ulfamuron formula t ion(TEP) to Plants Inhabiting Aquatic Environments.

Species % a.i. EC 50 

### Comments Toxicity Category Identification Numbe r

(Study Classification) 3. 7– 5. 9 m g f or

m

ul at i on/L (1.8–2 .9 m g a.i./L) EC 05 : 1.5 m g f o rm ul at i on/L (0 .7 5 m g a.i./L ); 9 5 % C

. I.: 0. 84

–2

. 6 m g f o rm ul at i on/L ( 0 .42– 1.3 m g a.i./L) NO AEC: 2. 2 m g fo rm ulation/L (1 .1 m g a.i./L) Pr ob it slop e: 3

. 2 7 ±0 .5 32 Growth r a te : EC 50 : 12 m g f o rm ul at i on/L (6 .0 m g a.i./L); 9 5 % C. I.: 1 0 – 13 m g fo rm ul at i on/L ( 5

. 0 –6 .5 m g a.i./L) EC 05 : 3.0 m g f o rm ul at i on/L (1 .5 m g a.i./L); 9 5 % C. I.: 1. 9–4. 6 m g f or

m

ul at i on/L ( 0 .95–2.3 m g a.i./L) NO AEC: 2. 2 m g fo rm ulation/L (1 .1 m g a.i./L) Pr ob it slop e: 2

. 7 6 ±0 .4 56
Mo st sensitiv e en dpo in ts: cell d e nsity an d b i omass Fres hwate r 49 .9 6 Cell density: 96

- hac ut e t o xi ci tyst udyo f Slig h tly to x ic MRI D 4 657 893 2 Diatom (Navicula EC 50 : >1 08 m g I R 58 78 50W G ( f orm u latio n ) (Acce ptable ) p e llicu lo s a ) fo rm ul at i on/L i ndi at om unde r st at i c (>54 m g a.i./L) co nd itio ns. Nomin a l conce ntr at i o ns: 7. 5, 1 5 , 3 0 , Growth r a te : 6 0 , an d 120 mg /L; m ean EC 50 : >1 08 m g measured conc entrations were fo rm ul at i on/L 7. 7, 1 5 , 2 9 , 5 6 , an d 10 8 m g /L , (>54 m g a.i./L) respectively.
B i omass : Endpoints a sse ssed: cell EC 50 : >1 08 m g d e nsity, b i o m ass, an d gr ow t h fo rm ul at i on/L rate. (>54 m g a.i./L) Cell density: En dp oi nt s EC 50 : > 1 0 8 m g affected: none form ulation/L (> 54 mg a . i./L) EC 05 : > 1 0 8 m g form ulation/L (> 54 mg a . i./L) NO AEC: 10 8 m g fo rm ulation/L (5 4 m g a.i./L)



### 108

### Table E-8. Acute Toxicity (T ier II) of Or thos ulfamuron formula t ion(TEP) to Plants Inhabiting Aquatic Environments.

Species % a.i. EC 50 

### Comments Toxicity Category Identification Numbe r

(Study Classification)

Fres hwate r di at om , (Na vicu la p e llicu lo s a ) 49 .9 6 B i omass : EC 50 : 1

. 6 m g fo rm ul at i on/L (0.8 m g a.i./L)
Mo st sensitiv e en dpo ints: bi om ass Growth r a te : EC 50 : >10 8 m g f o rm ul at i on/L (>54 m g a.i./L) EC 05 : >10 8 m g f o rm ul at i on/L (>54 m g a.i./L) NO AEC: 10 8 m g fo rm ulation/L (5 4 m g a.i./L)
B i omass : EC 50 : >10 8 m g f o rm ul at i on/L (>54 m g a.i./L) EC 05 : >10 8 m g f o rm ul at i on/L (>54 m g a.i./L) NO AEC: 10 8 m g fo rm ulation/L (5 4 m g a.i./L)
En dp oi nt s a ffe ct ed: n one 96

- hac ut e t o xi ci tyst udyo f I R 58 78 50W G ( f orm u latio n ) i ndi at om unde r st at i c co nd itio ns. Nomin a l conce ntr at i o ns: 0. 3 1 , 0. 6 3 , 1. 3, 2. 5, an d 5. 0 m g /L ; m ean measured conc entrations: 0. 28 , 0. 57 , 1. 1, 2. 3, an d 4. 6 mg /L

. Endpoints a sse ssed: cell den s i ty , bi om ass, gr owt hrat e
. Due t o 1 00 % i nhibi t i on o f cell d e n s ity int h e ad juv ant co nt ro l it is imp o s sib l e to discern the effects of the adjuvant from the effects of ort hos ul fam ur o n
. B i omass : EC 50 : 1. 6 m g f o rmul a ti o n/L (0.8 mg a.i./L) ; 9 5 % C.I.: 1. 5– 1. 7 m g f or

m

ul at i on/L ( 0 .75– 0.85 m g a.i./L) EC 05 : 0. 87 m g form ulation/L (0. 4 3 mg a . i./L) ; 95 % C

. I.: 0. 75

– 1

. 0 m g form ul at i on/L ( 0

. 3 7– 0. 5 0 m g a.i./L) H igh ly to x ic MRI D 4 657 893 5 (Su p p lem e ntal)



### 109

### Table E-8. Acute Toxicity (T ier II) of Or thos ulfamuron formula t ion(TEP) to Plants Inhabiting Aquatic Environments.

Species % a.i. EC 50 

### Comments Toxicity Category Identification Numbe r

(Study Classification)

Mari neAl gae M ari ne di at om 49 .9 6 B i omass : ( Skeletone m a cost atum ) EC 50 : 0

. 16 m g fo rm ul at i on/L (0.08 m g a.i./L)
Mo st sensitiv e en dpo ints: bi om ass NO AEC: 0. 57 m g fo rm ulation/L (0 .2 8 m g a.i./L ) Pr ob it slop e: 6

. 2 6 ±0 .4 93 Cell density: EC 50 : 2.4 m g f o rm ul at i on/L (1 .2 m g a.i./L); 9 5 % C. I.: 2. 3–2. 5 m g f or

m

ul at i on/L (1.1–1 .2 m g a.i./L) EC 05 : 1.6 m g f o rm ul at i on/L (0 .8 m g a.i./L); 9 5 % C. I.: 1. 5– 1. 8 m g f or

m

ul at i on/L ( 0 .75– 0.90 m g a.i./L) NO AEC: 1. 1 m g fo rm ulation/L (0 .5 5 m g a.i./L ) Pr ob it slop e: 9

. 9 8 ±0 .9 93 Growth r a te : EC 50 : 3.3 m g f o rm ul at i on/L (1 .6 m g a.i./L); 9 5 % C. I.: 3. 2– 3. 4 m g f or

m

ul at i on/L (1.6–1 .7 m g a.i./L) EC 05 : >1.1 m g fo rm ul at i on/L ( >0.55 m g a.i./L ) ; 95 % C.I.: N/A NO AEC: 1. 1 m g fo rm ulation/L (0 .5 5 m g a.i./L ) Pro b i t sl o p e: c oul d not be d eterm in ed
Mo st sensitiv e en dpo in ts: bi om ass 96

- hac ut e t o xi ci tyst udyo f I R 58 78 50W G ( f orm u latio n ) i nm ari ne di at o m under st at i c co nd itio ns. Nomin a l conce n trat i o ns: 0. 0 1 8 , 0. 04 1, 0

. 0 9 1 , 0.20 , 0.4 5 , an d 1.0 m g /L; mean measure d conce n trat i o ns: 0. 0 1 9 , 0. 04 3, 0

. 0 8 9 , 0.20 , 0.4 3 , an d 0.97 m g /L. Bo th n e g ativ e an d adj uvant c o ntr o l we re t e st ed inth is st u dy . Sig n i ficant inh i b ition o f all p aram eters occurre d i nth e ad juvant cont rol

. H igh ly to x ic MRI D 4 657 893 6 (Su p p lem e ntal)



### 110

### Table E-8. Acute Toxicity (T ier II) of Or thos ulfamuron formula t ion(TEP) to Plants Inhabiting Aquatic Environments.

Species % a.i. EC 50 

### Comments Toxicity Category Identification Numbe r

(Study Classification)

M ari ne di at om 49 .9 6 B i omass : ( Skeletone m a EC 50 : 24 m g cost atum ) fo rm ul at i on/L (12 m g a.i./L) Endpoints a sse ssed: cell d e nsity, b i o m ass, an d gr ow t h rate. B i omass : EC 50 : 0. 16 m g/L (0. 0 8 m g a . i./L) ; 95 % C

. I.: 0. 11

– 0

. 2 2 m g /L (0 .05– 0.1 1 m g a.i./L) EC 05 : 0. 05 9 m g/L ( 0 . 0 2 9 mg a . i./L) ; 9 5 % C.I

. : 0

. 0 27– 0.13 m g /L ( 0 .013 –0.06 m g a.i./L) NO AEC : 0. 04 3 m g /L (0 .0 2 1 m g ai/L) Pr ob it slop e: 3

. 8 6 ±0 .9 21 Cell density: EC 50 : 0

. 19 m g /L (0 .0 9 m g a.i./L) ; 95 % C.I

. : 0

. 1 3–0 .2 9 m g /L (0 .06– 0.1 4 m g a.i./L) EC 05 : 0

. 046 mg /L (0 .02 3 m g a.i./L) ; 95 % C.I

. : 0

. 0 19– 0.12 m g /L ( 0 .009 –0.06 m g a.i./L) NO AEC : 0. 04 3 m g /L (0 .0 2 1 m g ai/L) Pr ob it slop e: 2

. 6 8 ±0 .5 18 Growth r a te : EC 50 : 0

. 26 m g /L (0 .1 3 m g a.i./L) ; 95 % C.I

. : 0

. 2 3–0 .2 9 m g /L (0 .11– 0.1 4 m g a.i./L) EC 05 : 0

. 18 m g /L (0 .0 9 m g a.i./L) ; 95 % C.I

. : 0

. 1 5–0 .2 2 m g /L (0 .07– 0.1 1 m g a.i./L) NO AEC : 0. 04 3 m g /L (0 .0 2 1 m g ai/L) Pr ob it slop e: 11 .5 ±1 .51
En dp oi nt s a ffe ct ed: cel l d e nsity, b i o m ass, an d gr ow t h rates.
Mo st sensitiv e en dpo in ts: bi om ass 96

- hac ut e t o xi ci tyst udyo f I R 58 78 50W G ( f orm u latio n ) i nm ari ne di at o m under st at i c co nd itio ns. Nomin a l Slig h tly to x ic MRI D 4 657 893 3 (Acce ptable )



### 111

### Table E-8. Acute Toxicity (T ier II) of Or thos ulfamuron formula t ion(TEP) to Plants Inhabiting Aquatic Environments.

Species % a.i. EC 50 

### Comments Toxicity Category Identification Numbe r

(Study Classification)
Mo st sensitiv e en dpo ints: bi om ass conce ntrat i o ns: 3. 8, 7 .5 , 15 , 3 0 , an d 60 m g /L; m ean measured conc entrations were 3. 6, 7. 2, 1 5 , 2 9 , an d 5 9 m g /L

. Th e test co ncentration s were n o t corr e c t edfo r th e p e r c ent activ e ing r ed ien t int h e test substance. Endpoints a sse ssed: cell den s i ty , bi om ass (area un de r the curve), and growth rate. Agg r eg ationan d fl o ccu lation was observe di nthe 59 m g /L g r oup. B i omass : EC 50 : 24 m g f o rmul a tio n/L (1 2 m g a.i . /L ) ; 95 % C.I

. : 22

– 26 m g fo rm ul at i on/L ( 1 1– 1 3 m g a.i./L) EC 05 : 12 m g f o rmul a tio n/L (6.0 mg a.i./L) ; 9 5 % C.I.: 8. 8– 1 7 m g f or

m

ul at i on/L (4.4–8 .5 m g a.i./L) NO AEC: 15 m g fo rm ulation/L (7 .5 m g a.i./L) Pr ob it slop e: 5

. 5 6 ±0 .9 39 Cell density: EC 50 : 36 m g f o rm ul at i on/L (1 8. 0 m g a.i./L ); 9 5 % C

. I.: 33

–4 0 m g fo r m

ul at i on/L ( 1 6

. 5–20 .0 m g a.i./L) EC 05 : 23 m g f o rm ul at i on/L (1 1. 5 m g a.i./L ); 9 5 % C

. I.: 19

–2 8 m g fo r m

ul at i on/L ( 9 .5–1 4.0 m g a.i./L) NO AEC: 7. 2 m g fo rm ulation/L (3 .6 m g a.i./L) Pr ob it slop e: 8

. 5 2 ±0 .9 43 Growth r a te : EC 50 : 42 m g f o rm ul at i on/L (2 1 m g a.i./L); 95 % C. I.: 41 – 43 m g fo rm ul at i on/L ( 2 0. 5– 21.5 m g a.i./L)



### 112

### Table E-8. Acute Toxicity (T ier II) of Or thos ulfamuron formula t ion(TEP) to Plants Inhabiting Aquatic Environments.

Species % a.i. EC 50 

### Comments Toxicity Category Identification Numbe r

(Study Classification)

Fres hwate r vasc ul ar pl ant , duc k w eed (Le mna gi b ba ) 49 .9 6 Fron d nu mbe r : EC 50 : 1

. 4 μg fo rm ul at i on/L (0.7 μg a.i./L)
Mo st sensitiv e en dpo in t: fr ond num ber EC 05 : 7.0 m g f o rm ul at i on/L (3 .5 m g a.i./L); 9 5 % C. I.: 1. 3– 3 8 m g f or

m

ul at i on/L ( 0 .65– 19 .0 m g a.i./L) NO AEC: 7. 2 m g fo rm ulation/L (3 .6 m g a.i./L) Pr ob it slop e: 0

. 8 05± 0.370
Mo st sensitiv e en dpo in ts: bi om ass 7- d ac ut e t o xi c i tyst udyo f I R 58 78 50W G ( f orm u latio n ) in fres hwater vascular plant un d e r static con d ition s
. No m i n a l co ncen tration s : 0. 07 4, 0

. 1 6, 0

. 36 , 0. 81 , 1. 8, and 4.0 μg/L; mean m easured conce ntrat i o ns: 0. 0 7 4 , 0. 16 , 0. 52 , 0. 86 , 1. 9, an d 3. 9 μ g /L , respectively.
En dp oi nt s a sse ssed: num ber o f

fr ond s an d gr ow th r ate.
Excee di n g l yhi gh conce ntr at i o ns of a.i . (1 1 4 – 2 450 %) w e r e ob serv ed

. Fron d nu mbe r : EC 50 : 1. 4 μ g f o rmul a ti o n/L (0.7 μg a.i . /L) ; 95 % C.I.: 1

. 1– 1. 8 μ g f o rm ul at i on/L ( 0. 5 5– 0. 90 μga.i ./L ) EC 05 : 0. 28 μgform ul a t i o n/L (0 .1 4 μ g a.i . /L ) ; 95 % C

. I.: 0. 15

– 0

. 5 3 μgf o rm ul at i on/L ( 0 .07– 0.26 μg a.i./L) NO AEC: 0. 52 μg fo rm ul at i on/L (0 .2 6 μ g a
. i

. /L ) Pr ob it slop e: 2

. 3 6 ±0 .3 21 Growth r a te : EC 50 : 2.0 μgf o rm ul at i on/L (1 .0 μg a.i./L); 95 % C. I.: 1. 7– 2. 5 μ g f o rm ul at i on/L ( 0. 8 5– 1. 2 μ g a.i

. /L ) EC 05 : n o t d e termin ed NO AEC: 0. 52 μg Veryhig h ly MRI D 4 657 893 9 t oxi c (Acce ptable )



### 113

### Table E-8. Acute Toxicity (T ier II) of Or thos ulfamuron formula t ion(TEP) to Plants Inhabiting Aquatic Environments.

Species % a.i. EC 50 

### Comments Toxicity Category Identification Numbe r

(Study Classification)

Fres hwate r 49 .9 6 Fron d Numbe r : vasc ul ar pl ant , duc k w eed (Le mna gi b ba ) EC 50 : 1

. 5 μg fo rm ul at i on/L (0.75 μg a.i./L)
Mo st sensitiv e en dpo in t: fr ond num ber fo rm ul at i on/L (0 .2 6 μ g a
. i

. /L ) Pr ob it slop e: no t r e po rted
Mo st sensitiv e en dpo in t: fr on d num b er. 7- d ac ut e t o xi c i tyst udyo f I R 58 78 50W G ( f orm u latio n ) in fres hwater vascular plant un d e r static con d ition s
. No m i n a l co ncen tration s : 0. 02 8, 0

. 0 7 0 , 0

. 1 8 , 0. 4 4 , 1. 1, 2. 7, an d 6. 8 μ g/L ; m ean measured conc entrations for th e f o ur hi g h es t co n c entration s were 0.45 , 0. 97 8, 2

. 4 , and 5. 9 μ g/L

. Because the L O Q was 0. 20 0 μ g/L , l o wer co n c entration s were no t analytically determ ined. Endpoints a sse ssed: num ber of f

ro n d s an d gr owt h rate Fron d Numbe r : EC 50 : 1. 5 μ g f o rmul a ti o n/L (0 .7 5 μ g a.i . /L ) ; 95 % C

. I.: 1. 2– 1. 8 μ g f or

m

ul at i on/L ( 0 .60– 0.90 μg a.i./L) EC 05 : 0. 24 μgform ul a t i o n/L (0 .1 2 μ g a.i . /L ) ; 95 % C

. I.: 0. 14

– 0

. 4 1 μgf o rm ul at i on/L ( 0 .07– 0.20 μg a.i./L) NO AEC: 0. 45 μg fo rm ul at i on/L (0 .2 2 μ g a
. i

. /L ) Pr ob it slop e: 2

. 1 1 ±0 .2 14 Grow th r a te : EC 50 : 2.1 μgf o rm ul at i on/L (1 .0 μg a.i./L); 95 % C. I.: 2. 1– 2. 2 μ g f o rm ul at i on/L ( 1. 0 –1 .1 μg a.i./L) EC 05 : n o t d e termin ed NO AEC: 0. 45 μg fo rm ul at i on/L (0 .2 2 μ g a
. i

. /L ) Pr ob it slop e: no t r e po rted Veryhig h ly MRI D 4 657 894 0 t oxi c (Acce ptable )



### 114

### Table E-8. Acute Toxicity (T ier II) of Or thos ulfamuron formula t ion(TEP) to Plants Inhabiting Aquatic Environments.

Species % a.i. EC 50 

### Comments Toxicity Category Identification Numbe r

(Study Classification) Fro n dnum ber was t h e m o st sen s itiv e en dpo int. 

### V. Toxicityto Terres trial Anima l s

a. Birds, Acute and Subacute An acute oral toxicity study us ing the technical g r ade of the ac tive ingred ie nt is required to establish the toxicity of orthosul fam uron to birds. The preferred tes tspe c i es is either m allard duck (a waterfowl) or bobwhite quail (an upland gam e bird). Studies of the acute oral toxi city studies of orthosulfam ur on TGAI in m a llard duck (MRID 46260107; Acceptable) and bobwhite quail (MRI D 46260108; Acceptab l e) were sub m itted. Study details and results are summ arized in Table E-9

. Both studies indicate that orthosulfam uron is not more thanslightly toxic to m a llard duck s or bobwhite quail on an acute oral basis. The re ported acute oral LD 50 

### of >1960 m g a.i./kg body weight in bobwhite quail and m allard duck will be us ed to evalu ate the acute exposure of birds to ortho s ulfam uron. The guideline (71-1) is fulfilled. No acute oral toxicity studies of orthosulfam uron form ulations or degrad ates in av ian s p ecies were subm itted.
Table E-9. Acute Oral Toxici ty o f Technical Grade Orth os ulfamuro n (TGAI) to Birds.

Species % a.i. LD 50 

### Comments Toxicity Category Identification Numbe r

(Study Classification) Mallarddu ck s 9 7 .99 LD 50 : ( Anas >1 960 plat yr

hync h o s ) mg a.i./k g-b w

Bo bw h ite 9 7 .99 LD 50 : 1 4 -d o r al tox i city test withmallard du c k s
. Nom i nal do ses : 0 (ve h i c l e co ntr o l ), 5 0 0 , 1 000 , and 2 000 m g /k g- bw ; meanm easur ed : d o s es: 0, 5 0 5 , 1 005 an d 196 0 m g a.i./k g- bw , respectively. Slig h tly t oxi c MRI D 4 626 010 7 Accepta ble

No m o rtality o r sign s of tox i city inany treatm e nt group. No clinical signs of t oxi ci ty , ef fect s o n feed co ns um pt i on, bo dy wei g ht , or g ro s s nec ro p sy fi n d i ngs i nc o ntrol or

hi gh -d ose g r ou ps. LD 50 : >1 960 mg a . i./kg
- bw LOAEL: > 1 960 m g a.i./kg-bw N O A EL: 19 60 m g a.i./k g- bw 1 4 -dacut e oralto x i city in bo bwh ite qu a il. Slig h tly MRID 4 626 010 8



### 115

### Table E-9. Acute Oral Toxici ty o f Technical Grade Orth os ulfamuro n (TGAI) to Birds.

Species % a.i. LD 50 

### Comments Toxicity Category Identification Numbe r

(Study Classification) quai l ( Co linu s virg in ianu s ) >1 960 mg No m in a l co ncentration s : 0 (v eh icle contro l), 5 0 0 , 100 0, an d 20 00 m g /k g-bw ; m ean toxic (Acce ptable ) a.i./k g-b w m easured d o se s: <0. 3 (L OD , cont rol ) , 50 0, 98 8, an d 1 9 6 0 m g a.i ./kg- b w , respect i v el y . No m o rtality o r sign s of tox i city inany treatm e nt group. No clinical signs of t oxi ci ty , ef fect s o n feed co ns um pt i on, bo dy wei g ht , or g ro s s nec ro p sy fi n d i ngs i nc o ntrol or

hi gh -d ose g r ou ps. LD 50 : >1 960 mg a . i./kg
- bw LOAEL: > 1 960 m g a.i./kg-bw N O A EL: 19 60 m g a.i./k g- bw
En dp oi nt s a ffe ct ed: n one 

### Two acute dietary studies using the TGAI ar e required to establis h the toxicity of orthosulfam uron to birds. The preferred test sp ecies are m a llard duck and bobwhite quail. Acute dietary tox i city stud ies w ith m allard d u ck (MRID 46219040; Acceptable) and bobwhite quail (MRID 46219041; Acceptable) were subm itted. Study de tails and resu lts of these acute dietary studies are s umm arized in Table E-10

. In m allard d u cks (MRID 46219040; Acceptable) and bobwhite quail (MRI D 46219041; Acceptable) the acute LC 50 

### values were >4790 and >4980 m ga.i./kg diet (the highest concentratio ns tested), respectiv ely. These resu lts indicate th at orthosulfamuron TGAI is not more than slightly toxic to birds on an acute di etary basis. The lowest reported acute dietary LC 50 

### (>4790 m g a.i./kg diet) in m a llard ducks will be used to evaluate th e acute dietary exposure of birds to orthosulfam uron. Th e guideline (71-2) is fulfilled. No acute dietary toxicity studies of orthosulfam uron form ulations or degradates in avian species were subm itted.

116

### Table E-10. Acute Dietary Toxicity of Techni cal Grade Orthosulfamuro n (TGAI) to Birds.

Species % a.i. LC 50 

### Comments Toxicity Category Identification Numbe r

(Study Classification) Mallarddu ck ( Anas plat yr

hync h o s )

Bo bwh ite qu ail ( Co linu s virg in ianu s ) 9 7 .99 LC 50 : >4 79 0 m g a.i /kg di et

9 7 .99 LC 50 : >4 98 0 m g a.i./k g di et 8- d ac ut e di et aryt o xi ci tyt e st i nm a ll ard duc k. Nom i nal di et aryco nce ntr at i o ns: 0 ( c on tro l ) , 156 , 3 1 3 , 625 , 12 50, 250 0, an d 50 0 0 m g /kg di et ; m ean m easure d co n c entr ation s : 0 , 161 , 31 0, 60 3, 1 210 , 24 4 0 , an d 47 9 0 m g a.i ./k g di et , respectively.
No m o rtality, c lin ical sig n s of to x i city, or tr eatm e nt -rel at e d e ffect s o nb odywei g ht or

f

o o dc o ns um pti on were o b ser v e d

. LC 50 : > 4 7 9 0 mg a.i/k g di et . NO AEC (f or

m o rt al ity and t oxi ci ty ): 47 9 0 m g a.i ./k g di et LOAEC (fo r m o rtality an d toxicity): >4 790 m g a.i./k g d i et 8- d ac ut e di et aryt o xi ci tyt e st i n b obwh ite qu a il

. No m i n a l co ncentration s o f 0 ( c o n t r o l), 1 5 6 , 313 , 62 5, 1 250 , 25 00 , and 5000 m g /kg diet; m ean measure d conce ntrations were <7.5 (L O D , co n t r o l), 1 5 3 , 3 0 8 , 603 , 12 10, 245 0, an d 4980 m g a.i./kg diet, res p ecti v ely.
No m o rtality was ob serv ed during th e st

udy

. N o cl i n i cal si gns o f t o xi ci tyor tr eatm e nt -rel at e d e ffect s o nb odywei g ht or

f

o o dc o ns um pti on were o b ser v e d

. LC 50 : >4 980 mg a . i./kg diet N O A E C: 4 980 m g a.i./k g d i et (m o rtality an d clin ical sig n s ) LO AEC: >4980 m g a.i./kg d i et (m o rtality an d clin ical sig n s )
En dp oi nt s a ffe ct ed: n one Slig h tly MRI D t oxi c 4 621 904 0 (Acce ptable )

Slig h tly MRI D t oxi c 4 621 904 1 (Acce ptable )



### b. Birds, Chronic Avian reproduction studies using the TGAI are required for orthosulfam uron because birds m ay be subject to continuous exposur e to the pesticide, especiallypreceding or during the breeding season. The preferred test species ar e m a llard duck and bobwhite quail. Studies of the reproductive toxicity of orthosulfamuron TGAI in m a llard ducks (MRID 46578949; Acceptable) and bobwhite quail (MRI D 46578950; Acceptab l e) were sub m itted.

117

### Study details and results are summ arized in Table E-11

. Results of reproductive studies in m a llard ducks (MRID 46578949; Acceptab l e) and bobwhite quail (MRID 46578950; Acceptable) show no treatm ent -related effects on adult b i rd mortality, foo d consum ption, body weight, or reproductive param e ters

. No clinical signs or treatm ent-related effects in offspring survival or body weight were obs erved at the highest dietary c oncentrations tested in these studies (1280 m g a.i/kg diet). The NOAEC valu e of >1280 mg a.i/kg diet will be used to assess chronic risk of orthosulf am uron in avian spec ies. The guideline (71-4) is f u lf illed. No chronic toxicity studies of orthosulfam uron form ulations or orthosul fam uron degradates in avian species were submitted.
Table E-11. Chronic Toxicity of T echnical Grade Orthosulfamuron (TGAI) to Birds.

Species % a.i. NOA E C Comments Identification Numbe r

(Study Classification) Mallarddu ck 98 .5 6 NO AEC: ( Anas 1 280 m g plat yr

hync h o s ) a.i./k g d i et
En dp oi nt s affected: None

No rthe rn 98 .5 6 NO AEC: bo b whi t e quai l 1 280 m g ( Co linu s a.i./k g d i et virg in ianu s ) En dp oi nt s affected: none On e-g e n e rationreprodu ctiv e to x i city in m a ll ard MRI D duc k was asses s ed o v er a p pr o x i m at el y21 w eeks. 4 657 894 9 No m in a l co ncentration s : 0 (v eh icle contro l), 2 0 0 , (Acce ptable ) 50 0, an d 1 2 5 0 m g a.i ./kg diet. Mean-m easured conce ntr at i o ns were <5 0 (<L O D , c ont rol ) , 1 9 5 , 50 0, an d 1 2 8 0 m g a.i ./kg di et , res p ect i v el y . Th ere were no clin ical sig n s of tox i city an d no effect s o n pare nt al m o rt al i ty , fo o dc ons um pt i on, b o dyw e igh t, or r e pr odu ctiv e en dpo ints. O ffsp r i n g sho w e d no si g n s of t o xi ci tyor ef fect s i ns ur v i v al or bo dywei g ht

. NO AE C : 12 8 0 m g a.i . /k g di et LO AEC: >1280 m g a.i./kg d i et On e-g e n e rationreprodu ctiv e to x i city inb obwh ite MRI D quail was as ses sed over a p proxim a t ely 21 weeks. 4 657 895 0 No m in a l co ncentration s : 0 (v eh icle contro l), 2 0 0 , (Acce ptable ) 50 0, an d 1 2 5 0 m g a.i ./kg di et ; m ean m easure d conce ntr at i o ns: <5 0 (<LO D, c ont rol ) , 19 5, 5 0 0 , an d 1280 m g a.i./kg diet, res p ecti v ely. Th ere were no clin ical sig n s of tox i city an d no effect s o n pare nt al m o rt al i ty , fo o dc ons um pt i on, b o dyw e igh t, or r e pr odu ctiv e en dpo ints. O ffsp r i n g sho w e d no si g n s of t o xi ci tyor ef fect s i ns ur v i v al or bo dywei g ht

. NO AE C : 12 8 0 m g a.i ./k g di et LO AEC: >1280 m g a.i./kg d i et
En dp oi nt s a ffe ct ed: n one



### 118

### c. Mammals, Acute In an acute oral study (MRID 46219019), five young adult rats/sex (W istar – SPF, m a les 230­ 350 g, fe m a les 200-252 g) were dosed with orthos ulfam uron (93.7%). The dose was divided in two equal parts in deionized water and given at two hour intervals (10 m g /kg/tim e ). Evaluation param e ters included s i gn s of gross to xicity and morta lity f o r a subsequent period of 14 days. Initial and weekly body weights and necropsy find ing were recorded on all anim als. The LC50 is >5000 m g /kg, the highest and only tested concentration ( Table E-12 ).
Table E-12. Acute Toxicity of Technical Grade Orthosulfamuron (T GAI) to Rats.

Species % a.i. LC 50 

### Comments Toxicity Category Identification Numbe r

(Study Classification) Lab o rato ryRat (Ra ttus nor vegi c us ) 93 .7 LC 50 : >5 00 0 m g a.i /kg di et No m o rtality, c lin ical sig n s of to x i city, or tr eatm e nt -rel at e d e ffect s o nb odywei g ht or

f

o o dc o ns um pti on were o b ser v e d

. Practically n on- tox ic MRI D 4 621 901 9 (Acce ptable ) LC 50 : > 5 0 0 0 mg a.i/k g di et . NO AEC (f or

m o rt al ity and t oxi ci ty ): 50 0 0 m g a.i ./k g di et LOAEC (fo r m o rtality an d toxicity): >5 000 m g a.i./k g d i et



### d. Mammals, chronic In a two-generation reproduction study (MRID 46219033), IR5878 (98.5% a.i., batch # G009/02) was adm i nistered in the diet to 24 m a le and 24 fem a le HanBr l:W IST (SPF) rats/dose at concentrations of 0, 350, 1400, or 5600 ppm throughout the study for m a l e s and during prem ating, m ating, and gestation for fe m a les. Concen trations of the test article in the diet were reduced to 0, 225, 900, and 3600 ppm during lactation of the F 0 

### and F 1 

### dam s
. Dietary concentrations were selected on the basis of a prelim inar y one-generation study (MRID 46260106). One litter w a s produced in each gen e ration. Prem ating doses for the F 0 

### parental anim als were 0, 38.1, 145.3, and 634.5 m g/kg/day, respectively, for m a les and 0, 47.8, 205.0, and 764.9 m g/kg/day, respectively, for fem a les. Prem ating doses for the treated F 1 

### parental anim als were 0, 41.2, 164.7, and 711.9 m g/kg/day, respectively, for males and 0, 52.4, 214.8, and 888.3 mg/kg/day, respectively, for fe m a les. Due to unrealistically high food consum ption data, the calculated test item intake in this study is extrem ely high. Th is could possibly be due to food spillage of the powdered diet. Fo r a m o re realistic es tim ation of the actu al te st item intake, th e study author used values fro m a concurre nt 2-generation reproduc tion study (RCC 84 2842) perform e d with the same rat strain and sam e di et (although pelleted) to calculate achieved doses. At concentrations of 0, 350, 1400, 5600 ppm , the achieved prem ating doses for the F 0 

### parental anim als were 0, 22.2, 88.6, and 354.5 m g/kg/day, respectively, for m a les and 0, 25.6, 102.2, and 408.89 m g/kg/day, respectively, for fem a les. Ac hieved premating doses for the treated F 1 

### parental anim als were 0, 24.3, 97.0, and 388.1 mg /kg/day, respectively, f o r m a les and 0, 27.8, 111.2, and 444.6 m g/kg/day, respectively, for fem a les. These values are com p arable to those calculated using a generic conversion (20:1) of ppm to m g/kg/day. F 0 

### and F 1 

### parental anim als

119

### were adm i nistered test or control diet for 70 or 120 days , respectively, prior to m ating, throughout m ating, gestation, and lact ation, and until s acrifice. Atappro x im ately sixweeks of age, the F 1 

### p arental an imals were sub j ected to a F unctional Observational Battery (FOB) and tested f o r motor ac tiv ity.
No treatm e nt-related deaths or c linical signs of toxicity were observed in any group during the study. No treatm e nt-related adverse effect s on body weight, body weight gain, or food consum ption were observed during the prem ating inte rval in adult an im als of either generation or in F 0 

### and F 1 

### dam s during gestation and l actation. No abnorm a lities were observed in the FOB. No treatm e nt-related effects on organ weight and no gross lesions were seen in adu lts of either generation. High-dose fem a les of both generations had increased incidences and severity of kidney lesions. Tubular m i neralization was observed at sim ilar incidence in all groups but the m ean severity grade was 1.8 in both the high-dose F 0 

### and F 1 

### fem a les compared with 1.0-1.4 in the controls. The incidence (severity) of urothelial hyperplasia was 11/24 (1.3) in both F 0 

### and F 1 

### high-dose fem a les com p ared with 3-4/24 (1.0) fo r the control groups. The parental system ic LOAEL was 5600/3600 ppm for m a l e s and fem a l e s (354.5-388.1and 408.89-444.6 m g /kg/day, respectively), based on kidney lesions in F 0 

### and F 1 

### fe m a les. The parental system ic NOAEL was 1400/900 ppm in m a les (88.6-97.0 mg/kg/day) and fe m a les (102.2-111.2 mg/kg/day).
No treatm e nt-related differences in estrus cycle or estrus cycle length were observed between the treated and control fem a les of e ither generation and no differences in testicular and epididym al sperm counts, sperm m o tility, or sperm morphol ogy were found between th e treated and control m a les of either generation. Mating, fertility, and gestation indices, num ber of days to m ating, and gestation length were not affected by treatm e nt of either generation during litter production. Mean day of sexual m aturation and body weight were not affected in the F 1 

### anim als. For litters of both generations, live birth, viabil ity , lactation in dices, m eanlitter sizes, and sex ratios were sim ilar between the treated and contro l groups. N o treatm ent-re lated clinical signs of toxicity were observed in the pups during lactat ion and gross necropsy w a s unrem arkable. Body weight throughout lactation, and brain, spleen, thym us, and uterus weights on PND 21 were not affected by treatm e nt in eith er generation. High-dose F 1 

### m a les had significantly reduced (p ≤ 0.01) m o tor activity at all tim e points and in total activity. No differences in m otor activity were observed between treated and control fe m a les. The offspring toxicity L OAEL was 5600/3600 ppm for m a les and fe m a les (354.5-388.1and 408.89-444.6 m g/kg/day, respectively), base d on decreased moto r activity in F 1 

### m a les. The offspring NOAEL is 1400/900 ppm in m a les (88.6-97.0 m g/kg/day) and fe m a les (102.2-111.2 mg/kg/day) ( Table E-13 ). This study is Acceptable/Guidelin e and satisfies the guideline re quirem e nt for a two-generation reproduction study (OPPTS 870.3800; OECD 416) in rats.

Table E-13. Chronic Toxicity of T echnical Grade Orthosulfamuron (TGAI) to Birds.

120

### Species % a.i. NOAEL Comments Identification Numbe r

(Study Classification) Lab o rato ryRat 9 8 .56 N O A EL: MRI D (Ra ttus 8 8 .6 m g a.i./kg NO AE C : 12 8 0 m g a.i . /k g di et 4 621 903 3 nor vegi c us ) bw/ d ay LO AEC: >1280 m g a.i./kg d i et (Acce ptable )
En dp oi nt s affected: decrease d m o to r activ ity inF1 m a les



### e. Terrestrial Insects, Acute Contact A honey bee acute cont act study usin g the TGAI is requ ired b ecause outd oor use of orthosulfam uron will res u lt in hon ey bee exposure. The acute contact LD 50 

### , using the honey bee, Apis mellife ra , is an acute contact, singl e-dose laboratory test designe d to estim ate the quantity of toxicant required to cause 50% mortality in a test popu lation of bees. The TGAI is adm i nistered by one of two m e thods: whole body exposure to technical pesticide in a nontoxic dust diluent or topical exposure to technical p e sticide via m i cro-a pplicator. The m e dian lethal dose (LD 50 

### ) is expressed in m i crogram s of active ingredient per bee ( μ g a.i./bee). One acute contact study of the orthos ulfam uron TGAI in honey bees was s ubm itted (M RID 46219046; Acceptable). Study details and results are summ ar ized in Table E-14

. A 48-hour contact LD 50 

### >100 μg a.i./bee was shown in this st udy, indicating that orthosulfam uron (TGAI) is practically nontoxic to honey bees

. The guideline (141-1) is fulfil led. One acute oral toxicity test of ortho s ulfam uron TGAI in honey b ees was subm itted, yield i ng an acute o r al L D 50 

### >109.4 μg a.i./bee (MRID 46219046; Supplem ental). Study details and results are summ arized in Table E-14

. This acute o r al study is scientifically soun d and is classified as Sup p lem e ntal because the study is a non-guideline study and does not fulfill a guideline requirem e nt.
No acute co ntact tes t s L D 50 

### values in honey bees were submitted for orthosulfam uron form ulations or degradates.
Table E-14. Acute Toxicity of Technical Gr ade Orthosulfamuron (T GAI) to Honey Bees.

Species % a.i. LD 50 

### Comments Toxicity Category Identification Numbe r

(Study Classification) Acut e C o n t act T o xi ci ty T e s t Ho neybee ( Ap is mellifera ) 98 .5 4 LD 50 : >100 μg a.i./bee 4 8 -hco nt act tox i city test inthe ho neybee. N o m i nal doses: 0 (ne g at i v e c o ntr o l ), 0 (s ol ve nt co nt r o l), an d 10 0 μg / b ee. Practically no nt o xi c MRI D 4 621 904 6 (Acce ptable )

4 8 -hm o rtality: 0 % in n e g ative



### 121

### Table E-14. Acute Toxicity of Technical Gr ade Orthosulfamuron (T GAI) to Honey Bees.

Species % a.i. LD 50 

### Comments Toxicity Category Identification Numbe r

(Study Classification) co nt ro l. 2 % in so l v ent control, 10 % inth e 10 0 μg a.i./b ee g r oup. No sublet hal effects we re reporte d

. LD 50 : >1 00 μg a . i./bee Acut e Or al T oxi ci ty T e s t Ho neybee ( Ap is mellifera ) 98 .5 4 LD 50 : >109 .4 μg a.i./ b ee 4 8 -h o r al tox i city test inth e ho n e y bee. N o m i nal dos es: 0 (s ol ve nt cont rol) and 100 μ g /bee. Practically no nt o xi c MRI D 4 621 904 6 (Su p p lem e ntal)
4 8 -hm o rtality: 8 % int h e so lven t co nt ro l, 4 % in th e 100 μg a.i./ b ee treatm e nt. No sublet hal effects.
LD 50 : >1 09 .4 μg a . i. /b ee 95 % C

. I.: N/A NO AEC : 10 9. 4 μ g a.i ./ b ee Pr ob it slop e: N/A This st udy is cl assified as Supplem ental because the study is a n on- gu id elin e stu dy . 

### f. Earthw orms, Acute Toxicity No acute toxicity studies of orthosulfam uron TG AI, form ulations, or degr adates in earthworm s were subm itted.
g. Field Stu d ies on Non-Target Terrestrial Inv ertebra tes No field studies of orthosulfam uron TGAI, formulations, or degrad ates in non-target terrestrial invertebrates were submitted.
VI. Plants Inhabiting Terrestrial Environments
Terres trial p l ant testing (seedling emergence and ve getative v i gor) is requ ired f o r he rb icide s that have terrestrial non-residential out door use patterns and/or m ay have endangered or threatened plant sp ecies associated with the app lication site. Seedling em ergence and vegetative vigor testing of the following pl ant species and groups should be conduc ted: (1) six species of at least four dicotyledon fam ilies, includ ing one soybean species ( Glycine max ) and one root crop, and (2) four species of at leas t two m onoc otyle don fam ilies, inclu d ing one which is corn (Zea mays ). Tier II tests m easure the responses of plants at five or m ore testchem ical concen trations relative to a control. Tier II studies of the effect of the orthosulfam uron form ulation IR5878 50WG on seed em ergence and veg e tative vigo r in terres trial plants were subm itted. Study details and

122

### results of th ese stud ies are summ arized in Table E-13 (for most sensitive species for seedling em ergence and vegetative vigor), Table E-14 (synopsis for Tier II s eedling em ergence testing, including all endpoints), and Table E-15 (synopsis for Tier II vegetative vigor testing, including all endpoints). A Tier II seedling em ergence study wa s conducted in m onoc ots: corn ( Zea mays ), oat ( Avena sativa ), onion ( Allium cepa ), and rice ( Oryza sativa ) and; d i c o ts: c arro t (Daucus carota ), m ung bean ( Phaseolus aureus ), oilseed rape (Brassica napus ), pea ( Pisum sativum ), radish (Raphanus sativus ), and soybean ( Glycine max ) (MRID 46578941; Accep table). Rice was the m os t sensitive m onocot and dry weight was the m o st sensitive endpoint affected, with EC 05 

### and EC 25 

### values of 0.030 lbs a.i. /A and 0.078 lbs a.i. /A, resp ectively. Radish was the m o st sensitiv e dico t and dry weight was the most sensitive endpoint, with an EC 05 

### and EC 25 

### values of 0.017 lbs a.i./A and 0.040 lb s a.i./A, resp ectiv ely. Th ese valu es will b e used to assess the effects of exposure to orthosulfam uron on seedling em ergence in non-listed and listed terrestrial plants. The guideline (23-1[ a] ) is f u lf illed. A Tier II vegetative vigor study wa s conducted in m onocots: corn ( Zea m ays ), oat ( Avena sativa ), onion ( Allium cepa ), and rice ( Oryza sativa ) and; d i c o ts: c arro t (Daucus carota ), m ung bean ( Phaseolus aureus ), oilseed rape (Brassica napus ), pea ( Pisum sativum ), radish (Raphanus sativus ), and soybean ( Glycine max ) (MRID 46578942; Supplem ental). Onion was the m ost sensitive m onocot and dry weight was the m o st sensitive endpoint affected, with EC 05 

### and EC 25 

### values of 0.0013 lbs a.i./A and 0.0048 lbs a.i./A, respectively. Carrot w a s the m o st sensitive dicot and dry weight was the m o st sensitive endpoint, with EC 05 

### and EC 25 

### values of <0.0000664 lbs a.i./A and 0.00012 lbs a.i./A, respectively. This study was f ound to be scientifically sound, but is classified as Supplem ental since a NOAEC could not be determ ined for several species, particularly for legum e s pecies (MRID 46578942; S upplem ental). The guideline (23-1[b]) is f u lf illed.
Table E-13. Toxicity o f Orthosulfa muron Form ulation to Terrestrial Plants — Results of Tier II Testing (Seedling Emergence and Vegeta tive Vigor) for the Mo st Sensitive Species.

Species % a.i. Toxicity Values Comments Identification Numbe r

(Study Classification) Tier II Seedli ng Emer gence Mo no co ts: 4 9 .96 Mo st s e nsiti v e Co rn( Ze a monoc o t: rice mays ), (dr y w e igh t) Oat ( Ave n a EC 25 /IC 25 : 0

. 078 sa tiva ), lb s a.i./ A Oni on( Allium cepa ), an d Mo st s e nsiti v e Rice ( Oryz a dicot: r a dish sa tiva ) (dr y w e igh t) EC 25 /IC 25 : 0

. 040 Dico ts: lb s a.i./ A Carro t (Da uc u s Seedl i n g em ergence st u dy wi thIR 58 7 8 50 WG (f

orm u l at i on)

. Nom i nal appl i cat i on rat e s: 0 (ne g at i v e an d a d j uvant c o ntr o l s ), 0. 0 0 1 6 3 , 0. 00 4 8 9 , 0. 01 4 7 , 0. 0 4 4 0 , an d 0. 13 2 lb s a
. i

. /A

. Mean m easure d : 0 (ne g ative and adjuvant co nt r o ls) , 0

. 001 74 , 0.005 17 , 0

. 0 150 , 0

. 04 36, and 0. 13 5 lb s a
. i

. /A

. MRI D 4 657 894 1 (Acce ptable )

En dp oi nt s m easure d : em ergen ce o n day s 7, 1 4 an d 21 ; p lant heig h t an d dry w e igh t ond ay 2 1

. Most s e nsiti v emonoc o t: rice



### 123

### Table E-13. Toxicity o f Orthosulfa muron Form ulation to Terrestrial Plants — Results of Tier II Testing (Seedling Emergence and Vegeta tive Vigor) for the Mo st Sensitive Species.

Species % a.i. Toxicity Values Comments Identification Numbe r

(Study Classification)
car o ta ), Mung Bean ( Phase o lus aureus ), Oilseedrap e (Br assica n apu s ), Pea ( Pis u m sa tivum ), Rad i sh (Raph anu s sa tivu s ), an d Soybean ( Glycine max)

Tier II Ve getative Vigor Mo no co ts: 4 9 .96 Mo st s e nsiti v e Co rn( Ze a monoc o t: onion mays ), (dr y w e igh t ) : Oat ( Ave n a EC 25 : 0

. 004 8 lb s sa tiva ), O n io n a.i./A ( Alliu m cepa ), and Rice Mo st s e nsiti v e ( Oryza sa tiva ) dicot: c a rrot (dr y w e igh t) Dico ts: EC 25 : 0

. 000 12 lb s Carro t (Da uc u s a.i./A car o ta ), Mung Bean ( Phase o lus aureus ), Mo st sensitiv e p aram eter: drywei g ht
EC 50 /IC 50 : 0

. 15 lb s a.i./A; 9 5 % C.I. (0 .08 3–0 .2 8 lb s a.i./ A ) EC 25 /IC 25 : 0

. 078 lbs a.i./ A ; 95% C.I. (0 .03 1

– 0

. 2 0 lb s a.i./A) EC 05 /IC 05 : 0

. 030 lbs a.i./ A ; 95% C.I. (0 .00 33– 0

. 2 7 lb s a.i./A) NO AEC : 0. 04 36 l b s a.i

. /A Pro b i t sl o p e: 2. 34 ± 1

. 66
Most s e nsiti v edicot: r a dis h Mo st sensitiv e p aram eter: drywei g ht
EC 50 /IC 50 : 0

. 072 lbs a.i./ A ; 95% C.I. (0 .06 0 – 0. 08 8 lb s a
. i

. /A ) EC 25 /IC 25 : 0

. 040 lbs a.i./ A ; 95% C.I. (0 .02 9

– 0. 05 5 lb s a
. i

. /A ) EC 05 /IC 05 : 0

. 017 lbs a.i./ A ; 95% C.I. (0 .01 0

– 0. 02 9 lb s a
. i

. /A ) NO AEC : 0. 01 50 l b s a.i

. /A Pr ob it slop e: 2

. 6 3 ±0 .3 55 The st udy a uthors re ported that the oc casional si gns o f p hyt ot oxi ci ty di d not appear t o be do seresp o n si ve an d we re gene ral l ynot seve re. Add itio n a lly, so m e m o rtality was o b serv ed duri n g t h e t e st but , l i k e th e si gns o f phyt o t oxi ci ty , t h ere was n o a p pare nt dose

r espon se. V e g e tativ e v i go r study w ith IR5 878 5 0W G (f

orm u l at i on)

. Nom i nal appl i cat i on rat e s: 0 (ne g at i v e an d a d j uvant c o ntr o l s ), 0. 0 0 1 6 3 , 0. 00 4 8 9 , 0. 01 4 7 , 0. 0 4 4 0 , an d 0. 13 2 lb s a
. i

. /Af o r all species wit hthe ex ce ption of carrot and radis h ; m ean measured co nc entrations for rice, cor n , oat , oi l s e e d rape , an d so yb ean we re < 1 .0 0 pp b a .i

. (ne g at i v e an d ad j uvant cont rol s ), 0

. 0 017 0, 0

. 0 052 7, 0

. 0 150 , 0

. 03 66 , and0

. 11 5 lb s a.i./A; m ean measure dc o n centratio n s fo r on io n, pea, an d m ung bean we re < 1 .00 ppb a.i. (ne g at i v e an d a d j uvant c o ntr o l s ), 0. 0 0 1 6 9 , 0. 00 5 1 4 , 0. 01 4 3 , 0. 0 3 3 7 , an d 0. 12 5 lb s a
. i

. /A

. C arr ot an d radi sh were t e st ed at nom i n al conce ntr at i o ns of 0 ( n egat i v e and ad j uvant MRI D 4 657 894 2 (Su p p lem e ntal)



### 124

### Table E-13. Toxicity o f Orthosulfa muron Form ulation to Terrestrial Plants — Results of Tier II Testing (Seedling Emergence and Vegeta tive Vigor) for the Mo st Sensitive Species.

Species % a.i. Toxicity Values Comments Identification Numbe r

(Study Classification) Oilseedrap e (Br assica n apu s ), Pea ( Pisum sa tivum ), Rad i sh co n t r o ls) , 0

. 000 060 4, 0

. 0 0018 1, 0

. 0 005 43 , 0

. 0 016 3, an d 0.00 489 lbs a.i./ A ; m ean m easur ed co n c entration s were <1.00 ppb a.i. (n eg ativ e and ad

juv an t contro ls) , 0.000 0664 , 0

. 00 019 8, 0

. 0 005 87 , 0.001 69 , and 0

. 00 48 8 lb s a.i./A. (Raph anu s sa tivu s ), an d Soybean ( Glycine max) En dp oi nt s m easure d : s ur v i v al , pl ant hei g ht , and seedl i n g c o n d i t i on o nday s 7, 14 , an d 2 1 ; dry wei g ht o nday21

. M o s tse n s it iv e m o no co t: o n io n Mo st sensitiv e p aram eter: dry weigh t EC 50 : 0

. 012 lbs a.i./A; 9 5 % C.I. (0.008 3–0 .01 8 lb s a.i./ A ) EC 25 : 0

. 004 8 lb s a.i./A; 9 5 % C.I. (0 .0 028 – 0

. 0 084 lbs a.i./ A ) EC 05 : 0

. 001 3 lb s a.i./A; 9 5 % C.I. (0 .0 005 5– 0

. 0 030 lbs a.i./ A ) NO AEC : 0. 01 43 l b s a.i

. /A Pr ob it slop e andstan d ar d err o r : 1.69 ±0 .19 5
Mo st s e nsiti v edico t: c a rr ot Mo st sensitiv e p aram eter: dry weigh t EC 50 : 0

. 000 33 lb s a.i./ A ; 95 % C.I

. (0 .00 024 – 0

. 0 004 5 lb s a.i./A) EC 25 : 0

. 000 12 lb s a.i./ A ; 95 % C.I

. (0 .00 007 4– 0

. 0 001 9 lb s a.i./A) EC 05 : <0 .000 06 64 lb s a.i./A N O A E C: <0 .00 006 64 lb s a.i./A Pr ob it slop e andstan d ar d err o r : 1.52 ±0 .12 3 All species e xhibited phytot oxic effects thro ugh out th e stu dyandall effects app e ared to be dose-related.



### 125

## APPENDIX G: Federally Listed Speci es Associat ed w ith Orthosulfamuron Use Areas 

# Species Listing by State with Use Criteria
No spe c ie s were excl ude d Minimum of 1 Acre. 

### All Medium Types Reported Mammal, Marine mml, Bird, Amphibian, Re ptile, Fish, Crustacean, Bivalve, Gastropod, Arachnid, Insect, Dicot, M onocot, Ferns, Conf/cycds, Lichen rice Arkansas ( 13) spe c ie s: Taxa Critical Habitat Eagle, Bald Threate ned Bird No (Haliaeetus leucocephalus) Terr es tri a l Tern, Int erior (po pulation) Least Endangere d Bird No ( Ster na antillar u m ) Terr es tri a l Woodpecker, Re d-cockaded Endangere d Bird No (Picoides borealis) Terr es tri a l Fatmucket, Arka nsas Threate ned Bivalve No ( L am psilis powell i ) Fresh w ate r Mucket, Pink ( P ear l y mussel) Endangere d Bivalve No ( L am psilis abr upta) Fresh w ate r Mussel, Scalesh e ll Endangere d Bivalve No (Leptodealeptod on) Fresh w ate r Pearl y mussel, F a t Pocketbook Endangere d Bivalve No (Pota m ilus capax) Fresh w ate r Rock-pocketbook, Ouachita (=W heeler's pm) Endangere d Bivalve No (Arkansia wheele r i) Fresh w ate r Fruit, Earth (=ge ocarpon) Threate ned Dicot No (Geoca r pon m i ni

m u m) Terr es tri a l Har p er ella Endangere d Dicot No ( Ptilim nium nodosum ) Fresh w ate r Pondberr y Endangere d Dicot No (Lindera m e lissifolia) Terr es tri a l Sturgeon, Pallid Endangere d Fi s h No (Scaphirhynchus albus) Fresh w ate r Bat, Gra y Endangere d Mammal No ( M

yotis gr isescens) Subterra neous, Terr estrial 

### California ( 72) spe c ie s: Taxa Critical Habitat Frog, California Red-legged Threate ned Amphibian Ye s (Rana au ror a dra ytonii) Terr estrial, Fresh w at er Salamander, Cali fornia Tiger Endangere d Amphibian No (Ambystom a californiense) Terr estrial, Vern al pool Eagle, Bald Threate ned Bird No (Haliaeetus leucocephalus) Terr es tri a l



### 126

### California ( 72) spe c ie s: Taxa Critical Habitat Murrel et, Ma rbl e d Threate ned Bird Ye s (Brachyra m phus m a r m oratus m a r m o r atus) Fresh w ate r , T e rrestrial, Saltw a te r Ow l, No rthern S p otted Threate ned Bird Ye s (Strix occidentalis caurina) Terr es tri a l Pelican, Brow n Endangere d Bird No (Pelecanus occid entalis) Terr es tri a l Plover, Western Sno w y Threate ned Bird Ye s (Char adrius alexandrinus nivosus) Terr es tri a l Rail, California Clapper Endangere d Bird No (Rallus longirostris obsoletus) Terr es tri a l Fairy Sh rimp, Co nservanc y Fairy Endangere d Crustacean Ye s (Branchinecta conservatio) Vernal pool Fair ySh rimp, Ve rnal Pool Threate ned Crustacean Ye s (Branchinecta lynchi) Vernal pool Tadpole Shrimp, Vernal Pool Endangere d Crustacean Ye s (Lepidurus packa rdi) Vernal pool Adobe Sunbu rst, San Joaquin Threate ned Dicot No (Pseudobahia pe irsonii) Terr es tri a l Bird's-beak, Pal m ate-br acted Endangere d Dicot No (Cordylanthus pa lm atus) Terr es tri a l Bird's-beak, Soft Endangere d Dicot No ( C or dylanthus mollis ssp. m o llis) Br ackish, Saltw a ter Checker

- m allow , Keck' s Endangere d Dicot Ye s (Sidalcea keckii) Terr es tri a l Clover, Flesh y Ow l's Threate ned Dicot Ye s ( Castilleja cam p estr is ssp. su ccule nta) Vernal pool Dudle y a, San t a Clara Valle y Endangere d Dicot No ( D udleya setchellii) Terr es tri a l Evening-primros e , Antioch Dunes Endangere d Dicot Ye s (Oen othera delto ides ssp. howellii) Terr es tri a l Fiddleneck, Larg e-flo w ere d Endangere d Dicot Ye s (Am s inckia gran diflora) Terr es tri a l Golden Sunb urst , Hart w e g's Endangere d Dicot No (Pseudobahia ba hiifolia) Terr es tri a l Goldfields, Burke's Endangere d Dicot No (Lasthenia burkei ) Terr es tri a l Goldfields, Contr a Costa Endangere d Dicot Ye s (Lasthenia conjugens) Terr es tri a l Gras s , Hai r y Orc u tt Endangere d Dicot Ye s (O rc utti a pi lo s a ) Vernal pool G r ass, Sacr amento O r cutt Endangere d Dicot Ye s (Orcuttia viscida) Vernal pool



### 127

### California ( 72) spe c ie s: Taxa Critical Habitat Grass, Slender Orcutt Threate ned Dicot Ye s (Orcuttia tenuis) Vernal pool Jew e lflow e r , Califor nia Endangere d Dicot No (Caulanthus californicus) Terr es tri a l Meado w foam, B utte Count y Endangere d Dicot Ye s ( L im nanthes floccosa ssp. cal ifor n ica) Vernal pool Navarretia, Fe w - f l ow e r ed Endangere d Dicot No (Navarr e tia leucocephala ssp. pauciflora (=N. pauciflora)) Vernal pool, Te rr estrial Nav arreti a, Man y -fl owered Endangere d Dicot No (Navarr e tia leucocephala ssp. plie antha) Terr estrial, Vern al pool Pussy pa w s , M a ri posa Threate ned Dicot No (Calyptridium pulchellum ) Terr es tri a l Rock-cress, McDonald's Endangere d Dicot No (Arabis m c do naldiana) Terr es tri a l Spineflow e r , How e ll' s Endangere d Dicot No ( Chor i z

anthe howellii) Terr es tri a l Spurge, Ho over's Threate ned Dicot Ye s ( Cham aesyce hoover i) Vernal pool Stonecrop, Lake Count y Endangere d Dicot No (Parvisedum leio carpu m ) Vernal pool T h istle, Suisun Endangere d Dicot No (Cirsium hyd r oph ilum var. hydrop h ilum ) Br ackish, T e r r e str i al Tuctoria, Green 's Endangere d Dicot Ye s (Tuctoria g r eenei ) Vernal pool Wallflow e r , Menz ie' s Endangere d Dicot No (E

ry

s i

mu m me n z ie s i i ) Terr es tri a l Woolly -t hreads, San Joaquin Endangere d Dicot No (Monolopia (=Le m b e r tia) congdo nii) Terr es tri a l Chub, Hutto n Tui Threate ned Fi s h No ( G ila bicolor ssp.) Fresh w ate r Gob y , Tide water Endangere d Fi s h Ye s (Eucyclogobius n e wberryi) Fresh w ate r Salmon, Chinook (California Coas tal Run) Threate ned Fi s h Ye s (Oncor hynchus ( = Salm o) tsha wytscha) Fresh w ate r , Salt w a t e r, Br ackish Salmon, Chinook (Centr a l Valley Fall Run) Threate ned Fi s h No (Oncor hynchus ( = Salm o) tsha wytscha) Brackish, Freshwater, Salt w a te r Salmon, Chinook (Centr a l Valley Spring Run) Threate ned Fi s h Ye s (Oncor hynchus ( = Salm o) tsha wytscha) Brackish, Saltw a t e r, Fr esh w ater Salmon, Chinook (Sacramento River Winter Run) Endangere d Fi s h No (Oncor hynchus ( = Salm o) tsha wytscha) Saltw a te r, F r esh w at er, Br ackish Salmon, Coho ( C entral California Coast population ) Endangere d Fi s h No (Oncor hynchus ( = Salm o) kisutch) Saltw a ter , Br ackish, F r eshw ater



### 128

### California ( 72) spe c ie s: Taxa Critical Habitat Salmon, Coho (S outhern OR/ N ort hern CA C oast) Threate ned Fi s h Ye s (Oncor hynchus ( = Salm o) kisutch) Fresh w ate r , Brac kish, Saltw a ter Smelt, Delta Threate ned Fi s h Ye s (Hypo m esus tran spacificus ) Fresh w ate r , Brac kish Steelhead, (Calif ornia Cent ral Valle ypopulation ) Threate ned Fi s h Ye s (Oncor hynchus ( = Salm o) m ykiss) Brackish, Freshwater, Salt w a te r Steelhead, (Ce n t r al California Co ast population) Threate ned Fi s h Ye s (Oncor hynchus ( = Salm o) m ykiss) Fresh w ate r , Salt w a t e r, Br ackish Steelhead, (No rt hern California p opulation) Threate ned Fi s h No (Oncor hynchus ( = Salm o) m ykiss) Saltw a ter , Br ackish, F r eshw ater Sucker, Modoc Endangere d Fi s h Ye s (Catosto m u s m i crops) Fresh w ate r Trout, L ahontan Cutthroat Threate ned Fi s h No (Oncor hynchus clarki henshawi) Fresh w ate r Trout, Little Ker n Golden Threate ned Fi s h Ye s (Oncor hynchus aguabonita whitei) Fresh w ate r Trout, Paiute Cut throat Threate ned Fi s h No (Oncor hynchus clarki seleniris) Fresh w ate r Beetle, Delta Gre en Gr ound Threate ned Insect Ye s (Elaphrus viridis) Vernal pool, Te rr estrial Beetle, Valley El derber ryLongho r n Threate ned Insect Ye s ( D es m o cer u s califor nicus dim o r p hus) Terr es tri a l Butterfl y , Beh r en 's Silverspot Endangere d Insect No (Speyeria z e r

ene behrensii) Terr es tri a l Butterfl y , Lotis Blue Endangere d Insect No (Lycaeides argyr ogno m on lotis) Terr es tri a l Skipper, Carson Wandering Endangere d Insect No (Pseudocopaeod es eunus obscurus) Terr es tri a l Fox, Sa n Joaqui n Kit Endangere d Mammal No (Vulpes m a cr otis m u tica) Terr es tri a l Kangaroo Rat, F r esno Endangere d Mammal Ye s (Dipodo m ys nitra t oides exilis) Terr es tri a l Kangaroo Rat, Giant Endangere d Mammal No (Dipodo m ys ingens) Terr es tri a l Mountain Beaver , Point Arena Endangere d Mammal No (Aplodontia rufa nigra) Fresh w ate r , T err estrial Mouse, Salt Mar s h Harvest Endangere d Mammal No (Reithrod onto m y

s raviventris) Terr es tri a l Rabbit, Riparian Brush Endangere d Mammal No (Sylvilagus bach m ani ripa rius) Terr es tri a l Woodrat, Ripa rian Endangere d Mammal No (Neoto m a f u scipes riparia) Terr es tri a l



### 129

### California ( 72) spe c ie s: Taxa Critical Habitat G r ass, Colusa Threate ned Monocot No (Neostapfia colusana) Vernal pool Grass, San Joaq uin Valley Orcutt Threate ned Monocot Ye s (Orcuttia inaequa lis) Vernal pool Grass, Solano Endangere d Monocot Ye s (Tuc tori a muc r o n a ta) Vernal pool, Te rr estrial Lizard, Blunt-nosed Leopar d Endangere d Reptile No ( G am belia silus) Terr es tri a l Sea turtle, olive ridley Threate ned Reptile No (Lepidochelys olivacea) Saltw a te r Snake, Giant Ga rter Threate ned Reptile No (Tha m n ophis gigas) Fresh w ate r , T err estrial 

### Florida ( 24) spe c ie s: Taxa Critical Habitat Salamander, Flat w o ods Threate ned Amphibian No (Ambystom a cin gulatum) Fresh w ate r , Ver n al pool, Terr estrial Caracara, A udub on's Crested Threate ned Bird No (Polyborus plancus audubonii) Terr es tri a l Eagle, Bald Threate ned Bird No (Haliaeetus leucocephalus) Terr es tri a l Kite, Everglade Snail Endangere d Bird Ye s (Rostrha m u s soc i abilis plum beus) Terr es tri a l Plover, Piping Endangere d Bird Ye s (Char adrius m e lo dus) Terr es tri a l Scrub-Ja y , Florid a Threate ned Bird No (Aphelocoma coerulescens) Terr es tri a l Sparro w, Florida Grasshoppe r Endangere d Bird No (Ammodra m us savannaru m florid anus) Terr es tri a l Stork, Wood Endangere d Bird No (M

ycteria a m ericana) Terr es tri a l Woodpecker, Re d-cockaded Endangere d Bird No (Picoides borealis) Terr es tri a l Mussel, Oval Pig t oe Endangere d Bivalve No (Pleurobe m a pyrifor m e) Fresh w ate r Gour d, Okeecho bee Endangere d Dicot No (Cucurbita okeec hobeens is ssp. okeechobeensis) Terr es tri a l Jacquemontia, Beach Endangere d Dicot No (Jacquemontia r e clinata) Terr estrial, Coastal (dunes) Pawpa w , F our -p etal Endangere d Dicot No (Asim i na tetra m e r a) Terr es tri a l Polygala, Tin y Endangere d Dicot No ( Polygala sm allii) Terr es tri a l Sturgeon, Gulf Threate ned Fi s h Ye s (Acipenser oxyrinchus desotoi) Saltw a te r, F r esh w at er



### 130

### Florida ( 24) spe c ie s: Taxa Critical Habitat Cladonia, Florida Perforate Endangere d Lichen No (Cladonia perf or

ata) Terr es tri a l Panther, Florida Endangere d Mammal No (Pu m a (=F e lis) concolor coryi) Terr es tri a l Manatee, West I ndian Endangere d Marine mml Ye s (Trichechus m a n a tus) Saltw a te r Seagrass, Johnson's Threate ned Monocot Ye s (Halophila johnsonii) Coastal (dunes), Saltw a te r Sea turtle, gre en Endangere d Reptile No (Chelonia m y

das) Saltw a te r Sea turtle, ha w k s b ill Endangere d Reptile Ye s (Eret m ochelys im b r icata) Saltw a te r Sea turtle, leathe rback Endangere d Reptile Ye s (Der m o chelys coriacea) Saltw a te r Sea turtle, logger head Threate ned Reptile No (Carett a caretta ) Saltw a te r Snake, Eastern I ndigo Threate ned Reptile No (Dry m a rchon cor a is couperi) Terr es tri a l 

### Illinois ( 8) s pe c ie s: Taxa Critical Habitat Eagle, Bald Threate ned Bird No (Haliaeetus leucocephalus) Terr es tri a l Tern, Int erior (po pulation) Least Endangere d Bird No ( Ster na antillar u m ) Terr es tri a l Mucket, Pink ( P ear l y mussel) Endangere d Bivalve No ( L am psilis abr upta) Fresh w ate r Pearl y mussel, Or ange-foot ed Endangere d Bivalve No (Plethobasus cooperianus) Fresh w ate r As ter, Dec urre nt Fal s e Threate ned Dicot No (Boltonia decurre ns) Terr estrial, Fresh w at er Sturgeon, Pallid Endangere d Fi s h No (Scaphirhynchus albus) Fresh w ate r Bat, Gra y Endangere d Mammal No ( M

yotis gr isescens) Subterra neous, Terr estrial Bat, Indiana Endangere d Mammal Ye s ( M

yotis sodalis) Subterra neous, Terr estrial 

### Louisiana ( 19) spe c ie s: Taxa Critical Habitat Eagle, Bald Threate ned Bird No (Haliaeetus leucocephalus) Terr es tri a l Pelican, Brow n Endangere d Bird No (Pelecanus occid entalis) Terr es tri a l Plover, Piping Endangere d Bird Ye s (Char adrius m e lo dus) Terr es tri a l



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### Louisiana ( 19) spe c ie s: Taxa Critical Habitat Tern, California L east Endangere d Bird No ( Ster na antillar u m br

owni) Terr es tri a l Tern, Int erior (po pulation) Least Endangere d Bird No ( Ster na antillar u m ) Terr es tri a l Woodpecker, Re d-cockaded Endangere d Bird No (Picoides borealis) Terr es tri a l Mucket, Pink ( P ear l y mussel) Endangere d Bivalve No ( L am psilis abr upta) Fresh w ate r Pearlshell, Louisiana Threate ned Bivalve No (Marga ritifera he m beli) Fresh w ate r Chaffseed, Amer ican Endangere d Dicot No (Schwalbea a m e r icana) Terr es tri a l Fruit, Earth (=ge ocarpon) Threate ned Dicot No (Geoca r pon m i ni

m u m) Terr es tri a l Sturgeon, Gulf Threate ned Fi s h Ye s (Acipenser oxyrinchus desotoi) Saltw a te r, F r esh w at er Sturgeon, Pallid Endangere d Fi s h No (Scaphirhynchus albus) Fresh w ate r Bear, Louisiana Black Threate ned Mammal No (Ursus a m erican us luteolus) Terr es tri a l Manatee, West I ndian Endangere d Marine mml Ye s (Trichechus m a n a tus) Saltw a te r Sea turtle, gre en Endangere d Reptile No (Chelonia m y

das) Saltw a te r Sea turtle, ha w k s b ill Endangere d Reptile Ye s (Eret m ochelys im b r icata) Saltw a te r Sea turtle, Kemp 's ridley Endangere d Reptile No (Lepidochelys kem p ii) Saltw a te r Sea turtle, leathe rback Endangere d Reptile Ye s (Der m o chelys coriacea) Saltw a te r Sea turtle, logger head Threate ned Reptile No (Carett a caretta ) Saltw a te r 

### M

i ssissipp i ( 19) spe c ie s: Frog, Dusk y Gop her (Mississippi DPS) Endangere d Taxa Critical Habitat Amphibian No (Rana capito sevosa) Terr estrial, Fresh w at er Eagle, Bald Threate ned Bird No (Haliaeetus leucocephalus) Terr es tri a l Pelican, Brow n Endangere d Bird No (Pelecanus occid entalis) Terr es tri a l Plover, Piping Endangere d Bird Ye s (Char adrius m e lo dus) Terr es tri a l Tern, Int erior (po pulation) Least Endangere d Bird No



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### M i ssissipp i ( 19) spe c ie s: Woodpecker, Re d-cockaded Endangere d Taxa Critical Habitat Bird No (Picoides borealis) Terr es tri a l Pondberr y Endangere d Dicot No (Lindera m e lissifolia) Terr es tri a l Potato-bean , Pri c e's Threate ned Dicot No (Apios priceana) Terr es tri a l Q u illw o rt, Louisiana Endangere d Ferns No (Isoetes louisian ensis) Fresh w ate r , T err estrial Sturgeon, Gulf Threate ned Fi s h Ye s (Acipenser oxyrinchus desotoi) Saltw a te r, F r esh w at er Sturgeon, Pallid Endangere d Fi s h No (Scaphirhynchus albus) Fresh w ate r Bat, Gra y Endangere d Mammal No ( M

yotis gr isescens) Subterra neous, Terr estrial Bear, Louisiana Black Threate ned Mammal No (Ursus a m erican us luteolus) Terr es tri a l Sea turtle, gre en Endangere d Reptile No (Chelonia m y

das) Saltw a te r Sea turtle, Kemp 's ridley Endangere d Reptile No (Lepidochelys kem p ii) Saltw a te r Sea turtle, logger head Threate ned Reptile No (Carett a caretta ) Saltw a te r Snake, Eastern I ndigo Threate ned Reptile No (Dry m a rchon cor a is couperi) Terr es tri a l Tortoise, Gopher Threate ned Reptile No (Gop herus polyp hemus) Terr es tri a l Turtle, Y e llo w - bl otched Map Threate ned Reptile No (Grapte m ys flavim aculata) Fresh w ate r , T err estrial 

### M

i ssouri ( 15) spe c ie s: Taxa Critical Habitat Eagle, Bald Threate ned Bird No (Haliaeetus leucocephalus) Terr es tri a l Tern, Int erior (po pulation) Least Endangere d Bird No ( Ster na antillar u m ) Terr es tri a l Mucket, Pink ( P ear l y mussel) Endangere d Bivalve No ( L am psilis abr upta) Fresh w ate r Pear l y mussel, Curt is' Endangere d Bivalve No (Epioblasm a flor entina curtisii) Fresh w ate r Pearl y mussel, F a t Pocketbook Endangere d Bivalve No (Pota m ilus capax) Fresh w ate r As ter, Dec urre nt Fal s e Threate ned Dicot No (Boltonia decurre ns) Terr estrial, Fresh w at er Clover, Running Buffalo Endangere d Dicot No (Trifol iu m s t oloniferu m) Terr es tri a l



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### M i ssouri ( 15) spe c ie s: Taxa Critical Habitat Pondberr y Endangere d Dicot No (Lindera m e lissifolia) Terr es tri a l Darter, Niangua Threate ned Fi s h Ye s (Etheosto m a nia nguae) Fresh w ate r Shiner, Topeka Endangere d Fi s h Ye s (Notro pis topeka (=tristis)) Fresh w ate r Sturgeon, Pallid Endangere d Fi s h No (Scaphirhynchus albus) Fresh w ate r Beetle, American Bur y ing Endangere d Insect No (Nicrophor us americanus) Terr es tri a l Dragonfl y , Hine's Emerald Endangere d Insect No (So m atochlora hi neana) Fresh w ate r , T err estrial Bat, Gra y Endangere d Mammal No ( M

yotis gr isescens) Subterra neous, Terr estrial Bat, Indiana Endangere d Mammal Ye s ( M

yotis sodalis) Subterra neous, Terr estrial 

### Oklahoma ( 10) spe c ie s: Taxa Critical Habitat Eagle, Bald Threate ned Bird No (Haliaeetus leucocephalus) Terr es tri a l Plover, Piping Endangere d Bird Ye s (Char adrius m e lo dus) Terr es tri a l Tern, Int erior (po pulation) Least Endangere d Bird No ( Ster na antillar u m ) Terr es tri a l Woodpecker, Re d-cockaded Endangere d Bird No (Picoides borealis) Terr es tri a l Mussel, Scalesh e ll Endangere d Bivalve No (Leptodealeptod on) Fresh w ate r Rock-pocketbook, Ouachita (=W heeler's pm) Endangere d Bivalve No (Arkansia wheele r i) Fresh w ate r Darter, Leopa rd Threate ned Fi s h Ye s (Percina panthe rina) Fresh w ate r Beetle, American Bur y ing Endangere d Insect No (Nicrophor us americanus) Terr es tri a l Bat, Indiana Endangere d Mammal Ye s ( M

yotis sodalis) Subterra neous, Terr estrial Bat, O z ark Big-e a red Endangere d Mammal No (Coryno r hinus (= Plecotus) townsendii ingens) Terr estrial, Subte rraneo us 

### Tennessee ( 4) s pe c ie s: Taxa Critical Habitat Eagle, Bald Threate ned Bird No (Haliaeetus leucocephalus) Terr es tri a l Tern, Int erior (po pulation) Least Endangere d Bird No ( Ster na antillar u m ) Terr es tri a l



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### Tennessee ( 4) s pe c ie s: Taxa Critical Habitat Sturgeon, Pallid Endangere d Fi s h No (Scaphirhynchus albus) Fresh w ate r Bat, Indiana Endangere d Mammal Ye s ( M

yotis sodalis) Subterra neous, Terr estrial 

### Texas ( 18) spe c ie s: Taxa Critical Habitat Toad, Ho uston Endangere d Amphibian Ye s (Bufo houstonen sis) Terr estrial, Fresh w at er Crane, Who oping Endangere d Bird Ye s (Grus a m ericana ) Terr estrial, Fresh w at er Cur l ew , Eskimo Endangere d Bird No (Nu m enius bor ea lis) Terr es tri a l Eagle, Bald Threate ned Bird No (Haliaeetus leucocephalus) Terr es tri a l Pelican, Brow n Endangere d Bird No (Pelecanus occid entalis) Terr es tri a l Plover, Piping Endangere d Bird Ye s (Char adrius m e lo dus) Terr es tri a l Prairie-chicken, Attw at er's Gre at er Endangere d Bird No (Ty m

panuchus c upido attwate r i) Terr es tri a l Tern, Int erior (po pulation) Least Endangere d Bird No ( Ster na antillar u m ) Terr es tri a l Woodpecker, Re d-cockaded Endangere d Bird No (Picoides borealis) Terr es tri a l Da w n -fl o wer, T e xas Prai ri e (= Tex a s Bi tterw e ed) Endangere d Dicot No (Hymenoxys texana) Terr es tri a l Phlox , T e x a s Tr ailing Endangere d Dicot No (Phlox nivalis ssp. texensis) Terr es tri a l Beetle, American Bur y ing Endangere d Insect No (Nicrophor us americanus) Terr es tri a l Bear, Louisiana Black Threate ned Mammal No (Ursus a m erican us luteolus) Terr es tri a l Sea turtle, gre en Endangere d Reptile No (Chelonia m y

das) Saltw a te r Sea turtle, ha w k s b ill Endangere d Reptile Ye s (Eret m ochelys im b r icata) Saltw a te r Sea turtle, Kemp 's ridley Endangere d Reptile No (Lepidochelys kem p ii) Saltw a te r Sea turtle, leathe rback Endangere d Reptile Ye s (Der m o chelys coriacea) Saltw a te r Sea turtle, logger head Threate ned Reptile No (Carett a caretta ) Saltw a te r



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