### 1



# Problem Formulation for the Environmental Fate, Ecological Risk , Endangered Species , and Human Health Drinking Water Exposure Assessments in Support of the Registration Review of Rim sulfuron

N

- [[(4,6

- dimethoxy

- 2

- pyrimidinyl)amino]carbonyl]

- 3

- (ethylsulfonyl)

- 2

-

pyridinesulfonamide CAS: 122931

- 48

- 0 PC Code: 12900 9

Prepared by: Joseph DeC ant , Ecologist , ERB V Michael Barrett

, Senior Chemist , ERB V U.S. Environmental Protection Agency Office of Pesticide Programs Environmental Fate and Effects Division Environmental Risk Branch V 1200 Pennsylvania Ave., NW Mail Code 7507P Washington, DC 20460 Reviewed by: Anita Ullagaddi, Biologist, ERB I William Shaughnessy, Chemist, ERB I Approved by: Mah Shamim, PhD, Branch Chief , ERB V



### Date : September 13 , 2012

### 2



## Table of Contents

PURPOSE

................................ ................................ ................................ ................................ ............................... 3

STRESSOR SOURCE AND DISTRIBUTION

................................ ................................ ................................ ................. 3

M ECHANISM OF A CTION AND N ATURE OF C HEMICAL

................................ ................................ ................................ ............ 3
O VERVIEW OF P ESTICIDE U SE AND U SAGE

................................ ................................ ................................ .......................... 4

PROBLEM FORMULATION

................................ ................................ ................................ ................................ ...... 7

N ATURE OF R EGULATORY A CTION

................................ ................................ ................................ ................................ ..... 7
P REVIO US A SSESSMENTS

................................ ................................ ................................ ................................ ................. 8

EXPOSURE CHARACTERIS TICS

................................ ................................ ................................ ................................ 8

E NVIRONMENTAL F ATE

................................ ................................ ................................ ................................ ................... 8

ECOLOGICAL EFFECTS

................................ ................................ ................................ ................................ ........... 15

T OXICITY TO A QUATIC O RGANISMS

................................ ................................ ................................ ................................ . 15
T O XICITY TO T ERRESTRIAL O RGANISMS

................................ ................................ ................................ ............................ 16
D EGRADATE T OXICITY

................................ ................................ ................................ ................................ ................... 18
I NCIDENT R EPORTS

................................ ................................ ................................ ................................ ....................... 21

ECOSYSTEMS POTENTIAL LY AT RISK

................................ ................................ ................................ ..................... 22

R ISK H YPOTHESIS

................................ ................................ ................................ ................................ ......................... 23 Risk Hypothesis Description

................................ ................................ ................................ ............................... 23

ANALYSIS PLAN

................................ ................................ ................................ ................................ .................... 25

S TRESSORS OF C ONCERN

................................ ................................ ................................ ................................ ............... 25
M EASURES OF E XPOSURE

................................ ................................ ................................ ................................ .............. 26
M EASURES OF E FFECT

................................ ................................ ................................ ................................ ................... 26
E NDANGERED S PECIES A SSESSMENTS

................................ ................................ ................................ ............................... 28

PR ELIMINARY IDENTIFICA TION OF DATA GAPS

................................ ................................ ................................ .... 28

E NVIRONMENTAL F ATE

................................ ................................ ................................ ................................ ................. 28 Environmental Fate Data Gaps

................................ ................................ ................................ .......................... 30
E COLOGICAL E FFECTS D ATA

................................ ................................ ................................ ................................ ........... 31

REFERENC ES

................................ ................................ ................................ ................................ ......................... 34

APPENDIX 1. SUBMITT ED ENVIRONMENTAL FAT E AND EFFECTS STUDIE S

................................ .......................... 36

APPENDIX 2. UNCERTA INTIES RELATED TO TH E USE OF INCIDENT IN FORMATION FROM THE E COLOGICAL
INCIDENT INFORMATION SYSTEM

................................ ................................ ................................ ....................... 46

APPENDIX 3. SIP V.1 .0 INPUTS AND OUTPUT S

................................ ................................ ................................ .... 48

APPENDIX 4. STIR V. 1.0 INPUTS AND OUTPU TS

................................ ................................ ................................ .. 50

APPENDIX 5. THE RIS K QUOTIENT METHOD AN D LEVELS OF CONCERN

................................ .............................. 52

### 3



# Purpose

The purpose of this problem formulation is to provide an understanding of the environmental fate and ecological effects of the registered uses of rimsulfuron

. Rimsulfuron is a sulfonyl urea herbicide that is currently registered for various agricultural commodities and non

- agricultural

uses and can be applied using a variety of methods. This document will provide a plan for analyzing data relevant to rimsulfur on , as well as for conducting environmental fate and ecological risk, endangered species, and human health drinking water assessments for its registered uses. Additionally, this problem formulation is intended to identify data gaps, uncertainties, and pot ential assumptions used to address those uncertainties, relative to characterizing the ecological risk associated with the registered uses of rimsulfuron

.



# Stressor Source and Distribution

Mechanism of Action and Nature of Chemical

Rimsulfuron is a selective/systemic pyrimidinyl sulfonylurea herbicide and a member of the sulfonylurea class of compounds 1 

### . It has a mode of action that inhibits acetolactate synthase ALS (ALS is also known as acetohydroxyacid synthase AHAS) (HRAC Group B) 2 

### . ALS or AHAS is a key enzyme in the biosynthesis of certain amino acids in plants. The mode of action appears to require relatively low concentrations of the chemical. It is noted that repeated application might cause weeds to develop resistance to the sulfon yl urea fa mily of herbicides that would require the application of an herbicide resistance program.

In r imsulfuron the sulfonylurea moiety serves as a “bridge” between aminopyrimidine (the “ Q ” moiety on the

- NH

- or amine side of bridge) and pyridine (“ A ” on the

- SO 2

- or sulfonyl side of bridge) ring structures in the molecule as shown below in Figure 1

.

1 URL: http://www.alanwood.net/pesticides/class_herbicides.html#sulfonylurea_herbicides

2 URL: Stidham, Mark A. 1991. Herbicides That Inhibit Acetohydroxyacid Synthase. Weed Science 39(3):428

- 434.

### 4 Generic Molecular Structure for Sulfonylurea Herbicid es

Rimsulfuron Chemical Structure Figure 1 . Molecular structure of a sulfonylurea and rimsulfuron.



## Overview of Pesticide Use and Usage

Rimsulfuron is applied pre

- emergent or post

- emergent for weed control in various crop / non

crop uses via ground (broadcast and banded applications) and aerial applications. Rimsulfuron formulated products are available as an emulsifiable concentrate (field corn use only), water dispers i ble granules (dry flowable), or soluble concent rates (solid). Maximum single application
rates for the various crop and non

- crop use sites range between 0.0078 and 0.0625 lbs. a.i./A. In many cases the labels are not specific with regards to the maximum number of applications or application intervals per year for a particular use site.

Rim sulfuron herbicide is used for control of many broadleaf and grass weed species (primarily
pre

- and early post

- emergent) o n the following crop / non

- agricultural use sites ( Table 1 ) ; note that some use site description s on some label sites are not well

- defined

.

### 5

Table 1 . List of uses currently registered for rimsulfuron. Agricultural crops/soils (unspecified) Crabapple Pecan

Agricultural rights

- of

way/fencerows/hedgerows Drainage systems P istachio

Agricultural uncultivated areas Filbert (hazelnut) Plum Agricultural/farm premises Golf course turf plum, Japanese Airports/landing fields Grapefruit potato, white/ Irish Almond Grapes Prune Apple Hickory nut Pummelo (shaddock) Apricot Industrial / construction areas (outdoor) Quince

Beech nut Kumquat Rangeland Butternut Lemon Recreation area lawns (public) Calamondin Lime Sewage disposal areas Cashew Loquat S orghum Cherry Macadamia nut (bushnut) Soybeans (unspecified) Chestnut Mayhaw (hawthorn) Tangelo Chinquapin Nectarine Tangerines Citron (citrus) Nonagricultural rights

- of

way/fencerows/hedgerows Tomato

Citrus hybrids other than tangelo Nonagricultural uncultivated areas/soils Walnut ( English /black)

Commercial/industrial lawns Orange Commercial/institutional/industrial premises/equipment (outdoor) Ornamental sod farm (turf)

Corn (unspecified) Paved areas (private roads/sidewalks) Corn, field Peach Cotton (unspecified) Pear

Major use sites include potatoes, tomatoes, corn, almonds, grapes, apricots, peaches, plums/prunes, apples, cherries, pears, pistachios, nectarines, oranges, lemons, walnuts, cotton, soybeans, and sweet corn ( Table 2 ; USEPA 2011a ). The greatest agricultural use intensity is estimated to occur in parts of the Midwest and California ( Figure 2 ) 3 

### . Further details on rimsulfuron usage profile and history are available in the public docket for the registrat ion review of Rimsulfuron

.

3 Pesticide usage in Figure 2 is displayed as average pounds (for the years 2006

- 2010 ) per 1,000 acres of farmland in a Crop Reporting District (CRD

- aggregates of c ounties used in crop data reporting by the National Agricultural Statistics Service) to normalize for the variation in farmland between CRDs. Usage is based on private market surveys of pesticide use in agriculture (Proprietary Data, 2006

- 2010). The survey data are limited to the states that represent the top 80

- 90% of acreage for the individual crops, therefore, use may be occurring in regions outside the scope of the survey . CRDs showing no usage of pesticides may be due to either the lack of pesticide use in the region or non

- participation in the agricultural surveys. In addition, across the years, there may be variations in the specific crops included in the CRD survey. Th is may result in a lower annual average for the CRD.

### 6

Table 2

. Screening level estimates of agricultur al usage of rimsulfuron

. Percent Crop T reated Crop Lbs. A.I. Avg. Max.

Potatoes 6,000 30 35

Tomatoes 5,000 30 50

Corn 70,000 10 15

Almonds 6,000 10 15
Grapes 2,000 10 15 Apricots <500 10 20

Peaches <500 10 15

Plums/Prunes <500 10 15 Apples 1,000 5 10

Cherries <500 5 10

Pears <500 5 10

Pistachios <500 5 5

Nectarines <500 4 4 Oranges 1,000 2.5 5

Lemons <500 2.5 5

Walnuts <500 2.5 5

Cotton <500 1 2.5 Soybeans <500 1 2.5

Sweet Corn

, other corn for food uses <500 1 2.5

### 7

Figure 2 . Rimsulfuron a gricultural pesticide usage intensity 2006

- 2010 at the Crop Reporting District (CRD) level.

For additional details about Figure 2 , please refer to BEAD Chemical Profile (BEAD 2012). It is noted that the maps show usage all throughout the continental US, except for the southern states, with higher intensity use in California, the Northwest coast states and the Corn Belt

. 

# Problem Formulation

Nature of Regulatory Action

The Food Quality Protection Act of 1996 mandated EPA to implement a program for re assessing the risks of currently registered pesticides, i.e ., registration review 4 

### . All pesticides distributed or sold in the United States generally must be registered by EPA. The decision to register a pesticide is based on the consideration of scientific data and other factors showing that it will not cause unreasonable risks to human health, workers, or the environment when used a s directed on product labeling. The registration review program is intended to ensure that, as the ability to assess risk evolves and as policies and practices change, all registered pesticides continue to

4 http://www.epa.gov/oppsrrd1/registration_review/

### 8

meet the statutory standard of no unreasonable adv erse effects to human health and the environment. Changes in science, public policy, and pesticide use practices will occur over time. Through the new registration review program, the Agency periodically reevaluates pesticides to ensure that as change occu rs, products in the marketplace can be used safely.

As part of the implementation of the new Registration Review program pursuant to Section 3(g) of the Federal Insecticide, Fungicide and Rodenticide Act (FIFRA), the Agency is beginning its evaluation to determine whether rimsulfuron continues to meet the FIFRA standard for registration. This problem formulation for the environmental fate and ecological risk assessment chapter in support of the registration review is intended for the initial docket that opens the public phase of the review process.



## Previous Assessments

The last risk assessment conducted for rimsulfuron was an abbreviated assessment in March of 2012 for use on Chicory (D391028). This latter assessment included information from and was based on a previous assessment (D358867+) for corn and soybean conducted in 2009. The assessment for chicory found that these applications result in exposures exceeding Levels of Concern (LOCs) for risk to both listed and no n

- listed terrestrial plants. A previous assessment in 2011 for uses on Caneberry 13

- 07A and Bushberry Subgroup 13

- 07B (D384591) also found risk to federally listed aquatic vascular plants.



# Exposure Characteristics

Environmental Fate

Rimsulfuron is a relatively nonpersistent and relat ively mobile pesticide

. Table 3 provides a summary of its physi c ochemical and environmental fate properties

. Rimsulfuron does have persistent degradation products unlike other US

- registered sulfonylurea herbicides , whose de gradates are generally the product of the rupture of the sulfonylurea bridge (sometimes after formation of transitional degradates that retain the intact sulfonylurea bridge)

. T he most persistent moieties of this herbicide involve contraction of the sulfo nylurea bridge into a urea or amine bridge. The transformation products are discussed further below.

Upon pre

- emergent / post

- emergent application of rimsulfuron for weed control , the major quantities of the applied material is expected to be deposited on soil surfaces and be distributed within the surface layer of the soil depending on the amount of rainfall/irrigation for the required wetting

- in. Other relatively smaller quanti ties of the parent may reach nearby terrestrial/aqua tic systems by drift (but it should be noted that some crop species can be injured by very

- low dose exposure to some sulfonylurea herbicides). Runoff to surface waters may occur in the form of parent or a s the more persistent transformation products ( especially IN

- 70941 and IN

- 70942, see Table 4 and Table 5 for a summary of data on degradates formed in fate studies and the identi ties of these degradates, respectively ) depending on how soon after application the runoff
event occurs.

### 9

Rimsulfuron has a low vapor pressure (1.447 x10 - 11 

### atms. at 25 o 

### C) and is highly soluble in water (solubility 73 00 ppm at 2 5 o 

### C and pH 7 ). Based on submitted environmental fate studies, the chemical is short lived in aqueous systems (mainly affected by hydrolysis with hydrolysis half

lives ranging from 5

- 7 days in acidic/neutral conditions and < 1 day in alkaline conditions)

.

Table 3

. Nomenclature and physicochemical properties of rimsulfuron.

Parameter Value Reference

Chemical Classification Pyrimidinyl Sulfonylurea

Registrant Data and PPDB 1 Molecular Formula C 14 H 17 N 5 O 7 S 2

PC Code 129009

Chemical Name (IUPAC) 1

- (4,6

- dimethoxypyrimidin

- 2

- yl)

- 3

- (3

- ethylsulfonyl

- 2

- pyridylsulfonyl)urea

Chemical Name (CAS) N

- [[(4,6

- dimethoxy

- 2

- pyrimidinyl)amino]carbonyl]

- 3

- (ethylsulfonyl)

- 2

- pyridine sulfonamide

CAS Number 122931

- 48

- 0

Pesticide Classification Herbicide

MRIDs 413563

- 01 Molecular Weight 431.44
Physical State Solid

pKa 4

Water Solubility (ppm) Parent 7,300 @ pH 7/25 o C ; 135 ppm @ pH 5; 5,560 ppm @ pH 9

IN

- 70941 0.7 @ pH 7/25 o C

IN

- 70942 0.2 @ pH 7/25 o C
Vapor pressure (25 o C) 1.1x10 - 8 torr Equal to 1.447x10 - 11 atm
Henry's Law Constant 1.40x10 - 12 atm. m 3 . mole - 1 (Calculated)

Octanol/Water Partition, K ow 1 @ pH7 and 87 @ pH 5 (log K OW 0.034 @ pH7 &1.94 @ pH 5)

1 PPDB = Pesticide Properties Database or Footprint database. URL: 

### http://sitem.herts.ac.uk/aeru/iupac/Reports/586.htm

Parent rimsulfuron is relatively short

- lived i n aerobic/anaerobic soil systems. In three aerobic soil metabolism test soils (two of these studies are still in review, so these values are preliminary)

, the t 1/2 

### ranged from 21 to 48 days

. Concentrations of the IN

- 70941 degradate peaked within 90 days after application and were still present at 20% of applied in two of the test soils incubated at 20 o 

### C. IN

- 70942 concentrations rose subsequent to formation of IN

- 70941 and had not perceptibly declined at study termination in any of the three test soils. S horter half

- lives were determined under field conditions: t 1/2 

### = 5 to 18 days. In an anaerobi c pond water / sediment system rimsulfuron degraded rapidly ( t 1/2 

### = 4 to 5 days ) and neither IN

- 70941 or IN

7094 2 were particularly persistent ( IN

- 70941 peak concentration s were 43 to 45 % 14 days after application of rimsulfuron to the test system and later declined to less than 1% while IN

- 70942 concentrations peaked at 10 to 12% 30 days after application and declined to 0.1% of applied when the study was terminated after 365 days ). N one of the transformation products from IN

-

### 10

70941 were identifie d; however, none were reported to peak at greater than 10% of the applied
par ent on a molar basis. In contrast, in the same pond water / sediment test system sterilized by autoclaving, IN

- 70942 reached a peak concentration of 37 to 42% of applied rimsulfur on from 30 to 365 days post

- treatment (the last sampling date). Rimsulfuron appears not to be subject to
aqueous or soil photolysis.

Table 4

. A summary of the environmental fate data for rimsulfuron.

Parameter Value MRID

Hydrolysis t 1⁄2 = 4.5

- 4.7days @ 25 o C, pH 5;

t 1⁄2 = 7.1

- 7.3days @ 25 o C, pH 7;
t 1⁄2 = 4.2

- 10.9Hours @ 25 o C, pH 9.

Major degradates (from contraction of the sulfonylurea bridge): IN

70941 (degrading into IN

- 70942) Minor degradates (from cleavage of the sulfonylurea bridge): IN

- E9260 and IN

- J290 and IN

- T5831 (only @ pH 5). 413563

- 33, Acceptable

Direct photolysis in
water at pH 7 Half

- lives in irradiated samples (11.0

- 12.4 days) were longer than the dark controls (6.4

- 6.5 days) sugges ting that Direct ph otolysis is NOT an important degradation pathway

.
Major and Minor degradates : Similar to hydrolysis although irradiation was associated with reduced conversion of the transformation product IN

70941 into IN

- 70942 and/or enhanced degradation of IN

- 70942. Formation of IN

- E9260, IN

- J290, and the un

- identified polar compounds appeared to be enhanced. 419316

- 08, Acceptable

Photolysis on soil Half

- lives in irradiated/dark control samples were in the range of 11

- 12 days indicating that photolysis on soil is NOT an important degradation pathway

.
Major and Minor degradates : Similar to hydrolysis although irradiation appeared to increase the formation of soluble un

- identified polar compounds. 419316

- 09, Acceptable

Aerobic soil metabolism t 1⁄2 = 21.3 days for two labels (R 2 = 0.87

- 0.94 ; separate tests done with

pyrimidine and pyridine labeled parent ) in Sassafras sandy loam soil from Penns Grove, NJ (Sand= 77%, Silt= 14%, Clay 9%, pH 6.7, Organic matter= 1.1%, CEC= 3.2 meq/100 g).

These data are still in r eview : t 1⁄2 = 21.5 days for two labels (R 2 = 0.95) in Traver sandy loam soil from Madera, CA (Sand= 53%, Silt= 28%, Clay 19%, pH 7.4

– 7.5, Organic matter= 1.7%, CEC= 19.1 meq/100 g).

t 1⁄2 = 48.1 days for two labels (R 2 = 0.82) in Arkansaw sandy loam soil from Arkansaw, WI (Sand= 76%, Silt= 16%, Clay 8%, pH 6.8

– 7.3, Organic matter= 3.7 %, CEC= 13.7 meq/100 g).

Major degradates (from contraction of the sulfonylurea bridge): IN

70941 further degrading into IN

- 70942) plus IN

- E9260 (from cleavage of the sulfonylu rea bridge; only quantified in one of the three test soils )

Minor degradates (from cleavage of the sulfonylurea bridge): IN

- J290 and IN

- T5831. 41356334 : Acceptable 48332003 : In review

### 11

Parameter Value MRID

Anaerobic aquatic metabolism t 1⁄2 = 4.2 days for combined labels (R 2
= 0.98; note separate results for

pyrimidine and pyridine labeled product are available from this study) in Farm pond in Mississauga, Ontario, Canada (sediment classified as a loam with Sand=44%, Silt= 30%, Clay 26%, pH 7.6, Organic matter= 5.4%, CEC= 29.2 meq/100 g). Major degradates were identified: IN

- 70941 (most persistent, up to 43

- 45% of applied at 7 to 14 days after treatment) and the subsequently formed IN

- 70942 which was up to 10

- 12% at 30 DAT but declined rapidly thereafter. 48332004, In Review

Anaerobic soil metabolism t 1⁄2 = 17.9

- 18.1 days range for two labels (R 2 = 0.91

- 0.99) in Sassafras sandy

loam soil from Penns Grove, NJ (same soil used in the aerobic soil study).

Major/Minor degradates: Same as the aerobic soil. 41356335, Acceptable

Aerobic aquatic metabolism t 1⁄2 =0.5

- 2 Days at 25 o C in the water column;

t 1⁄2 = 59

- 77 Days at 5 o C in the water column.

Important Note: Calculated half

- lives m ight NOT represent an aerobic aquatic system because of exposure to light and the use of extremely diluted sediment ; but note that photolysis has not been found to be a major dissipation pathway Also, a newer study is currently under review.

Major/Minor degradat es: Similar to hydrolysis. 43288502, Supplemental (45490802 : in review)

Adsorption/ Desorption (K d and K oc in L Kg - 1 ) [Pyrimidine

- 2

- 14 C]:

Cecil sandy loam (NC): K d = 0.23 and K oc = 19 Fargo clay loam (ND): K d = 1.36 and K oc = 55 Sassafras sandy loam (NJ): K d = 0.32 and K oc = 55 Flanagan silt loam (IL): K d = 1.52 and K oc = 61 (limited data also available on some degradates, please refer to Table 6 the “Environmental Fate” section of this Problem Formulation document.) 41356336, Acceptable

Terrestrial Field/Lysimeter Dissipation 1 Greenville, MS: t 1⁄2 = 09 Days (average in the top 0

- 3”)

Madera, CA: t 1⁄2 = 08 Days (average in the top 0

- 3”) Rochelle, IL: t 1⁄2 = 18 Days (average in the top 0

- 3”) Newark, DE: t 1⁄2 = 05 Days (average in the top 0

- 3”)

Major degradates: IN

- 70941 (degrading into IN

- 70942) Minor degradates: None identified as the bridge

- cleavage degradates may have fallen below the LOD (LOD ≤ 10% of the applied) 419316

- 06, 419316

- 10, Acceptable

Bioconcentration in Fish: Waived following request (MRID 413563

- 39) due to low K ow =1 at pH7.

1 The terrestrial field dissipation study for a soil in Newark, Delaware submitted under MRID 419316

- 10 was upgraded to acceptable

.


### In the natural environment, the major route s of dissipation of rimsulfuron are expected to be hydrolysis and / or bio

- transformation. A dditionally, a dsorption/desorption studie s suggest that rimsulfuron may be highly mobile and vulnerable to run

- off and leaching ( K oc 

### ranged from 19

- 74 L Kg - 1 

### ). Therefore, the chemical may enter aquatic systems via run

- off and erosion. A lthough there is a potential for rimsulfuron parent to reach groundwater when conditions promote its stability and relatively rapid subsurface transport, it is also true that its persistence is relatively low compared to most pesticides which have been commonly detected in groundwater. The soil mobility / lea chability of the primary degradates IN

- 70941 and IN

- 70942 is somewhat less than for parent rimsulfuron ( Table 6 ) but these compounds are more environmentally persistent than

### 12

parent rimsulfuron. Significant leaching was not confirmed in th e field dissipation studies but it is uncertain whether residues that may have leached could be confirmed g iven the sampling meth ods and detection limits of the analytica l methods

.
Rimsulfuron is expected to transform/degrade into a number of products under different environmental conditions. The t wo consistently major degradates for rimsulfuron result from contraction of the sulf

on yl urea

- bridge (IN

- 70941 and IN

- 70942 )

. A third major degradate (in one aerobic soil metabolism study only) results from cleavage of the sulfonylurea bridge ( IN

E9260 ) (an aminopyrimidine degradate, IN

- J290, is formed from the remainder of the cleaved

mo lecule and, while reported as a major degradate for some other sulfonylurea herbicides, is not major for rimsulfuron) . P lease refer to Figure 3 for s tructures of the degrada tes and identified pathways ; full chemical names are provided in Table 5 . In contrast, the minor degradates are cleavage degradates (IN

- J9260 in systems other than aerobic soil, IN

- J290 and IN

- T5831). Note that In

- J290 is an aminopyrimdine compound that is also a degradation product of several other registered sulfonylurea herbicides. Mobility of the transformation products/degradates were evaluat ed by thin layer chromatography (TLC ) and results indicate high mobility to IN

- E9260 and high to medium mobility for I N

- 70941, IN

- 70942 (this persistent degradate had highly variable estimated mobility between the test soils) and IN

- J290 ( Table 6 ). Solubility was
rep orted for only IN

- 70941 and IN

- 70942 and was 0.7 ppm for the first and 0.2 ppm for the second. These solubilities are four orders of magnitude smaller than for the parent compound. Considering quantities formed and relative persisten ce of transformation p roducts/degradates , all are expected to reach aquatic systems in varied concentrations. In addition, most of the parent that reaches aquatic systems by drift is expected to transform under aerobic conditions by hydrolysis into (the usually) transient IN

- 7 0941 then into the usually persistent IN

- 70942 (only in the single biologically active anaerobic aquatic test system did IN

- 70942 degrade substantially) . The time line for this event is expected to be as follows: IN

- 79041 at the short to medium

- term (becau se it transforms into IN

- 70942), IN

- 70942/IN

- E9290/In

- J290 at the medium to long

- term. IN

- 70942 is expected to be the terminal and persistent degradate under aerobic conditions but transforms further into multiple unidentified minor polar products under anaerobic conditions (≤10% AR)

.

Table 5

. Rimsulfuron transformation products/degradate code/chemical names.
Applicant's Code IUPAC Chemical Name



### IN

- 70941 N

- (4, 6

- Dimethoxy

- 2

- pyrimidinyl)

- N

- ((3

- ethylsulfonyl)

- 2

- pyridinyl))Urea

IN

- 70942 N

- ((3

- Ethylsulfonyl)

- 2

- pyridinyl)

- 4, 6

- dimethoxy

- 2

- pyrimidineamine)

IN

- E9260 3

- (Ethylsulfonyl)

- 2

- pyridine sulfonamide

IN

- J290 2

- Amino

- 4, 6

- dimethoxy pyrimidine

IN

- T5831 N

- (4, 6

- Dimethoxy

- 2pyrimidinyl) Urea

### 13

Table 6

. Mobility of parent rimsulfuron and its transformation products/degradates (K oc 

### values).

Ad/Des Method 1 TLC Method 2

Parent Parent IN

- 70941 IN

- 70942 IN

- E9260 IN

- J290 Cecil sandy loam 19 51 58 41 44 284 Fargo clay loam 55 63 357 317 6 ND 3 Sassafras sandy loam 55 41 79 207 110 ND Flanagan silt loam 61 74 142 1,398* 6 834 Woodstown sandy loam ND ND ND ND ND 393 Keyport silt loam ND ND ND ND ND 362 Mobility Class 4 Very high

- High High

- Medium (except *=Low) Medium

1 K d calculated from a 4

- hour/4 concentrations adsorption/desorption experiments; results from MRID 41356336

. 2 K d calculated from R f values using Hamaker equation; 3 ND= No Data; results from MRID 41356337

. 4 Mobility class as per: McCall, et al. 1980. Estimation of chemical mobility in soil from liquid chromatographic retention times. Bull. Environm en tal Contamination. Toxicology. 24, 190

- 195.

### 14

Figure 3 . Identified transformation/degradation pathways for rimsulfuron in soil and
water systems. Parent Rimsulfuron

IN

- 70941 : Rimsulfuron Urea

degradate IN

- J290: Pyrimidine Amine
IN

- E9260 : Pyridine Sulfonamide

Sulfonylurea

- Bridge Cleavage ( MINOR in all systems, Except as indicated)

MAJOR in one Aerobic Soil Only Sulfonylurea

- Brid

g e Contraction (

MAJOR in all systems) Sulfonylurea Bridge

Pyrimidine Ring Pyridine Ring

IN

- 70942: Rimsulfuron Amine degradate IN

- T5831 Pyridine Urea

### 15



# E cological effects

Toxicity to Aquatic Organisms

Rimsulfuron is considered practically non

- toxic to most aquatic animals on an acute basis ( Table 7 ) . This includes freshwater fish (rainbow trout LC 50 

### > 390 ppm; bluegill sunfish LC 50 

### > 390 ppm), freshwater invertebrates ( Daphnia magna LC 50 

### > 360 ppm), and estuarine/marine organisms (sheepshead minnow LC 50 

### > 110 ppm; mysid shrimp LC 50 

### > 110 ppm; oyster shell deposition EC 50 

### > 120 ppm). In contrast, vascular plants are extremely sensitive to rimsulfuron. The most sensitive aquatic plant tested is duckweed (EC 50 

### = 11.6 ppb , NOAEC = 0.09 ppb ). Non

- vascular plants appear to be less sensitive than aquatic vascular plants, with the most potentially sensitive being Selenastrum capricornutum that showed a non

- definitive EC 50 

### and a NOAEC of 29 ppb.

While information exists on the acute toxicity of rimsulfuron to aquatic animals, chronic toxicity data is either lacking or in review. Three freshwater fish early life

- stage (ELS) studies are currently in review, as are two daphnid life

- cycle studies, i n order to determine the chronic toxicity of rimsulfuron to freshwater fish and invertebrates. One of the fish ELS studies and one of the daphnid life

- cycle studies tests the effects of a formulated product, while the other studies test the technical prod uct of rimsulfuron. However, no data have been submitted relative to the chronic toxicity of rimsulfuron to marine/estuarine species. Depending on the acceptability of the freshwater studies, they may provide insight into the potential for toxicity to es tuarine/marine species due to chronic exposure to rimsulfuron.

Table 7 . Most sensitive endpoints for aquatic species.

Species (common name) Measure of

Effect End

point Duration (hours) Toxicity

value (mg a.i./L) Test

substance (% a.i.) Study

Classification Reference

(MRID)

Freshwater Fish Lepomis macrochirus (Bluegill Sunfish) Mortality LC 50 96 >390 98.8% Acceptable 41356308

Oncorhynchus mykiss (Rainbow Trout) Mortality LC 50 96 >390 98.8% Acceptable 41356307

Freshwater Invertebrates Daphnia

magna (Water Flea) Mortality EC 50 48 >390 98.8% Acceptable 41356309

Estuarine/Marine Fish Cypridon variegatus (Sheepshead Minnow) Mortality LC 50 96 >110 99% Acceptable 42471303

### 16

Species (common name) Measure of

Effect End

point Duration (hours) Toxicity

value (mg a.i./L) Test

substance (% a.i.) Study

Classification Reference

(MRID)

Estuarine/Marine Invertebrates Americamysis bahia (Mysid shrimp) Mortality LC 50 96 >110 99% Acceptable 42471302

Crassostrea virginica (Eastern oyster) Shell

deposition EC 50 96 >120 99% Acceptable 42471301

Aquatic Plant Lemna gibba (Duckweed) Biomass EC 50 14 days 11.6 ppb 98.57 Acceptable 42471308

Selenastrum capricornutum (Green algae) Cell count,

biomass, growth rate EC 50 120 >29 ppb 98.57 Acceptable 42471305



## Toxicity to Terrestrial Organisms

Rimsulfuron is considered practically non

- toxic to most terrestrial animals ( Table 8 ) . This includes birds (mallard LD 50 

### > 2000 mg/kg; bobwhite quail LD 50 

### > 2250 mg/kg; mallard and bobwhite quail LC 50 

### > 5620 ppm), mammals (rat LD 50 

### > 5000 mg/kg), and bees (LD 50 

### > 100 ug/bee). The NOAEC in an avian reproduction study with bobwhite quail is 1250 ppm (No adverse effects were identified up to the maximum dose) , and the NOAEL for mammals based on the rat is 165 mg/kg body weight ( bwt )

. No data have been submitted relative to the acute toxicity to passerine bird species or to the chronic toxicity to the Mallard duck. These two species therefore represent an uncertainty ; however, given the lack of effects in the other avian studies it is unlikely that these other species would be sensitive to rimsulfuron

.
In contrast, plants are extremely sensitive to rimsulfuron. For seedling emergence, plant height was the most sensitive parameter (EC 25 

### = 0.0006 lb ai/A for the most sensitive monoco t and EC 25 

### = 0.00013 for the most sensitive dicot). For vegetative vigor, root weight was the most sensitive parameter (EC 25 

### = 0.00004 lb ai/A for the most sensitive monocot and 0.00003 lb ai/A for the most sensitive dicot). For both types of plant studi es, NOAEL values could not be determined for the most sensitive species because effects were seen at all test concentrations. And in each study the technical grade active ingredient was mixed with a buffered solution and combined with a surfactant rather than the test being conducted with a typical end

- use product as required by the CFR 40 part 158 guidelines.

Terrestrial plants appear to be very sensitive to rimsulfuron exposure. While toxicity data were available for endpoints related to systemic growth, seedling emergence and visual injury, these guideline studies are not designed to capture reproductive endpoints. There is some evidence 5 

### to

5 Snipes et al. 1992, Bansal et al. 1999; Fletcher et al. 1993, 1995,1996; Bhatti et al. 1995; Al

- Khatib et al. 1992; Boutin et al. 2000; Asghari and Evans 1992

### 17

suggest plant reproductio n may be affected by sulfonylurea herbicides at levels below effects on vegetative growth or visual injury (Fletcher et al ., 1993). Uncertainty regarding the potentially greater sensitivity of terrestrial plant reproduction has been discussed extensively in the environmental fate and effects assessment for chlorsulfuron (D330621 ). However, an analysis by the EFED Plant Technical Team revealed that p lants exposed to SU herbicides during the reproductive life stage are likely to exhibit adverse effects on r eproduction, generally expressed as reduced seed number or reduced seed weight. Based on the latest data analysis, these effects are expected to occur at similar concentrations to those effects determined in the guideline vegetative vigor studies (850.415 0) so further data are not requested at this time.

Table 8 . Most sensitive endpoints for terrestrial species.
Species
(common name) Measure of

effect End

- point Toxicity Value Test

Substance (% a.i.) Study

Classification Reference

(MRID)

Birds

Anas platyrhynchos (Mallard Duck) Mortality L D 50 >2000 ppm >2250 ppm 98.8%

25% Acceptable

Acceptable 41931629

41931630

LC 50 >5620 ppm

>1378 ppm 98.8%

25% Acceptable

Supplemental 41356306

41931633

Colinus virginianus (Northern Bobwhite Quail) Mortality LD 50 >2000 ppm >2250 ppm 98.8%

25% Acceptable

Supplemental 41356304

41931631

LC 50 >5620 ppm

>1339 ppm 98.8%

25% Acceptable

Supplemental 41356305

41931632

Colinus virginianus (Northern Bobwhite Quail) Avian

Reproduction NOAEC 1250 ppm

99% Acceptable 43277201

LOAEC >1250 ppm

Mammals

Rattus norvegicus (laboratory rat) Mortality Oral LD 50 >5000 mg/kg 25%

98.8%

25%

25.7% Acceptable

Acceptable Acceptable Acceptable 41356311

41356310
41931634
47091007

Inhalation LC 50 >5.4 mg/L

(TGAI) 98.8%

26.5%

25%

98.6% Acceptable

Acceptable Acceptable Acceptable 41356314

41931625
41931637
41931636

### 18

Species
(common name) Measure of

effect End

- point Toxicity Value Test

Substance (% a.i.) Study

Classification Reference

(MRID)

Reproductive and fetal toxicity, lower body weight gain NOAEL 165 mg/kg bwt 98.8% Acceptable 41931644

LOAEL 830 mg/kg

bwt

Terrestrial Invertebrates

Apis mellifera (Honey Bee) Mortality LD 50 >100 μg/bee 98.8% Acceptable 41356331

Terrestrial Plants 1

Sorghum bicolor (sorghum) Seedling

Emergence

EC 25 0.0006 98.8% Supplemental 42471304

Triticum aestivum
(wheat) Vegetative

Vigor 0.00004 98.8% Supplemental 42471304

Brassica campestris
(field mustard) Seedling

Emergence EC 25 0.00013 98.8% Supplemental 42471304

Vegetative Vigor 0.00003 98.8% Supplemental 42471304

1 Toxicity values are in lbs/Acre corresponding to a rate of application.



## Degradate Toxicity

A number of degradates of parent rimsulfuron have been identified from the various fate studies, as previously highlighted in Figure 3 and Table 5 . From the list of degradates that have been identified, only three of them are considered major degradates with formation rates at or above 10% of the applied parent compound in one or more studies and only two of these degradates were consistently detected at peak concentrations that were greater than 5 to 10% of applie d material

. None of the degradates , major or minor, have an intact sulfonylurea bridge

. The two consistently major degradates (IN

- 70941 and IN

- 70942) are the product of bridge contraction to form a urea compound and /or an amine derivative. Data are avai lable for a few taxa on the major degradates as summarized in Table 9 , and, given uncertainty because of non

- definitive endpoints, none of the studies show any of the degradates to be more toxic than the parent compound

. Estimates of toxicity using structure activity relationships ( ECOSAR in EpiSuite v.

### 19

4.1 6 

### ) for the three major degradates were calculated and are summarized in Table 10

. It is also important to note that the EPA Health Effects Division (HED) Metabolism Committee concluded that only parent rimsulfuron was of to xicological concern to mammals 7



### .

Table 9

. Toxicity of the three major degradates of rimsulfuron to various taxa. Degradate Organism Toxicity MRID (classification)

IN

- 70941 Sorghum /Oilseed

Rape NOAEC: 0.122 lb/A

EC 25 

### : > 0.122 lb/A 47702508

(Supplemental) Duckweed NOAEC: 3.6 m g/L

EC 50 

### : > 11 m g/L 47702512

(Acceptable)

IN

- 70942 Rainbow Trout LC 50 

### : > 175 mg/L 47702502 (Supplemental) Daphnia magna EC 50 

### : 179 mg/L 47702505 (Supplemental) Chironomus riparius NOAEC: 0. 143 m g/L

(pore water) LOAEC: > 0.143 mg/L (pore water) 47702503

(Supplemental)

Sorghum /Oilseed Rape NOAEC: 0.122 lb/A

EC 25 

### : > 0.122 lb/A 47702507

(Supplemental) Duckweed NOAEC: 0.0 159

m g/L EC 50 

### : > 0.0 159 m g/L 47702509

(Supplemental)

Selenastrum capricornutum NOAEC: 9.9 mg/L

EC 50 

### : > 9.9 mg/L 47702510

(Supplemental)

IN

- E9260 Sorghum /Oilseed

Rape NOAEC: 0.0244 lb/A

EC 25 

### : > 0.122 lb/A 47702506

(Supplemental) Duckweed NOAEC: 3.7 mg/L

EC 50 

### : > 130 mg/L 47702511

(Supplemental)

Table 10 . EcoSAR estimates of toxicity based on structure activity relationships. Degradate Structural Class Most Sensitive Estimated Endpoints IN

- 70941 Substituted Ureas

Amides Acute Fish: 15.5 ppm Daphnid: 10.8 ppm Green Algae: 0.214 ppm Chronic Fish: 0.092 ppm

Daphnid: 0.143 ppm Green Algae: 0.052 ppm

6 EPISuite (Estimation Programs Interface Suite) version 4.1 was used. EPISuite is a software developed by the EPA Office of Chemical Safety and Pollution Prevention in collaboration with the Syracuse Research Corporation (SRC). EPISuite is a collection of programs that estimates physical chemical and environmental fate properties for mainly organic compounds.

7 

### D200158, March 29, 1994.

### 20

IN

- 70942 Neutral Organics Acute Fish: 191.6 ppm Daphnid: 110.2 ppm Green Algae: 55.4 ppm Chronic Fish: 20.1 ppm

Daphnid: 13.0 ppm Green Algae: 21.6 ppm IN

- E9260 Amides Acute Fish: 6421.3 ppm Daphnid: 1325.0 ppm Green Algae: 3.6 ppm Chronic Fish: 38.0 ppm

Daphnid: 17.5 ppm Green Algae: 0.4 ppm

The data in Table 9 in combination with toxicity estimates from EpiSuite 4.1 structural activity relationships (SAR) in Table 10 indicate that the degradate IN

- 70941 has low acute toxicity to all organisms

. Chronic exposure , however, presents a different picture for IN

- 70941. In some aquatic environments, IN

- 70941 can be relatively persistent . Furthermore, the estimated endpoints based on SARs show that fish and aquatic invertebrates may be sensitive to chronic exposure to the amide moiety where estimated toxicity endpoints are several orders of magnitude lower than acute endpoints

. However, EFED does not a nticipate requesting additional toxicity data on this degradate due to the levels of estimated toxicity relative to previously modeled peak EEC’s and the conservative assumption that all of the parent transforms into the IN

- 70941 degradate. A recent risk assessment for soybean and corn (D358867+) that evaluated the maximum use rate revealed peak EEC’s for the parent ranging from 0.459 ppb up to 1.380 ppb. If the entire parent compound converted to equivalent concentrations of IN

- 70941, exposure would stil l be over an order of magnitude below the chronic toxicity endpoints for aquatic taxa based on the SAR estimates.

In terms of aquatic vascular plants, t he toxicity of IN

- 70941 from a laboratory study show ed that Lem n a gibba has an EC 50 

### of > 11 ppm, which is several orders of magnitude greater than the EC 50 

### for the parent rimsulfuron. Therefore, IN

- 70941 is less toxic to aquatic vascular plants than parent rimsulfuron. C onsidering that IN

- 70941 is a substituted urea, data for another related urea (d iuron , PC035505 ) can also be used for comparison. The data for diuron indicate s that non

vascular aquatic plants are more sensitive than vascular aquatic plants by a factor of five

. The most sensitive non

- vascular plant is Selenastrum capricornutum with an EC 50 

### of 2.4 ppb , but Lemna has an EC 50 

### of 15 ppb. Applying this same non

- vascular to va scular ratio established by diur on to IN

- 70941, an estimate of the non

- vascular EC 50 

### would therefore be approximately 2.2
ppm. Consequently, aquatic non

- vascular plants are also much less sensitive to IN

- 70941 compared to the parent rimsulfuron

.
Similarly, data for the degradate IN

- 70942 in Table 9 in conjun ction with SAR toxicity estimates from Table 10 support the conclusion that this degradate is also less toxic to either terrestrial or aquatic organi sms compared to parent rimsulfuron

. In the case of freshwater invertebrates, IN

- 70942 appears to be more toxic than the parent compound, though the toxicity is relatively low compared to potential concentrations in the environment. In addition, this degr adate was not identified to be of concern to mammals by HED. However, fate data show

### 21

that this terminal degradate is persistent in the environment. While the current body of available literature indicate s that this degradate appears to present a low pote ntial for concern to terrestrial and aquatic organisms due both to low toxicity to various taxa and low use rates of rimsulfuron

, there is uncertainty as to how the persistence of this degradate may affect its fate in the aquatic environment over an extended period of time following multiple years of consecutive applications

.

As shown in Table 10

, aquatic animal taxa do not appear to be sensit ive to the degradate IN

E9260 based on estimated toxicity endpoints . The taxa of concern based on these estimated toxicity endpoints narrow the focus to plant taxa. Actual d ata on terrestrial plants indicate that IN

- E9260 would not alter the risk picture from that obtained by the parent compound. As for aquatic plants, o ne study tested the effects of the degradate IN

- E9260 on the growth and biomass of Lemna gibba

. Biomass, yield based on dry weight, and growth rate based on dry weight were significantly reduced at the highest treatment level relative to the negative control. The 7

- Day NOAEC and EC 50 

### values for all three endpoints were 3.7 and >130 mg ai/L, respectively. This degradate evidently shows much less toxicity than the parent compound to aquat ic vascular plants by several orders of magnitude. The estimated value based on SAR ’s reveals that the non

vascular plants are more sensitive than aquatic vascular plants by an order of magnitude. Nonetheless, toxicity estimates for IN

- E9260 reveal that it is much less toxic to aquatic plants than parent rimsulfuron.

In summary, the three major degradates in both the aquatic and terrestrial environments (IN

70941, IN

- 70942, and IN

- E9260) are less toxic to most taxa than the parent rimsulfuron . The exception is the potential toxicity to aquatic organisms due to chronic exposure to IN

- 70941. EFED does not anticipate requesting additional toxicity data on this degradate due to the levels of estimat ed toxicity relative to previously modeled peak EEC’s and the conservative assumption that all of the parent transforms into the IN

- 70941 degradate.



## Incident Reports

Incident reports submitted to EPA since approximately 1994 have been tracked by assignme nt of “incident numbers” in an Incident Data System (IDS), microfiched, and then entered into a second database, the Ecological Incident Information System (EIIS, see Appendix 2 ; USEPA 2007b). A preliminary review of the EIIS and the Avian Incident Monito ring System (AIMS), which is maintained by the American Bird Conservancy, indicates that there are no incidents for wildlife. Since r imsulfuron was first registered

, t here were 26 incident s report ed in the EIIS that show incidents that involve plant damag e where rimsulfuron was applied to agricultural crops (corn, soybean, and potato). The magnitude of damages described in the various incidents ranged from 6.5 acres of damage (possibly caused by rimsulfuron) to corn up to 1600 acres of soybean (misuse). Only 6 of the incidents of plant damage are considered probable or highly probable as caused by rimsulfuron, whereas 20 of the incidents are considered only possibly or unlikely resulting from exposure to rimsulfuron.

In addition to the incidents recorded in EIIS, additional incidents have been reported to the Agency in aggregated incident reports. Pesticide registrants report certain types of incidents to

### 22

the Agency as aggregate counts of incidents occurring per produ ct per quarter. Ecological incidents reported in aggregate reports include those categorized as “minor fish and wildlife” (W

- B), “minor plant” (P

- B), and “other nontarget” (ONT) incidents. “Other nontarget” incidents include reports of adverse effects to insects and other terrestrial invertebrates. For rimsulfuron, which was first registered in 2005, registrants have reported a total of 12 minor incidents, with seven incidents related to plants, one related to other nontargets, one related to wildlife, t wo related to domestic animals, and one related to human exposure.

In the risk assessment, the incidents will be further evaluated to determine if the reported incidents represent current patterns of use for rimsulfuron. Examples of additional consider ations are mitigation ( e.g ., reduced application rates), product cancellations, and changes in use patterns that have occurred since the date of the reported incidents.

An absence of reported incidents should not be construed as the absence of incidents. Incident reports for non

- target organisms typically provide information only on mortality events and plant damage incidents. Except for phytotoxic effects in terrestrial plants, sublethal effects, such as reduced growth or impaired reproduction, are rare ly reported. EPA’s changes in the registrant reporting requirements for incidents in 1998 may account for a reduced number of reported incidents. Registrants are now only required to submit detailed information on ‘major’ fish, wildlife, and plant inciden ts. Minor fish, wildlife, and plant incidents, as well as all other nontarget incidents, are generally reported aggregately and are not included in the EIIS. In addition, there have been changes in state monitoring efforts due to a lack of resources. Ho wever, the incident data that are available suggest that exposure pathways for rimsulfuron are complete and that exposure levels are sufficient to result in field

- observable effects.



# Ecosystems Potentially at Risk

The ecosystems potentially at risk are o ften extensive in scope; therefore, it may not be possible to identify specific ecosystems during the development of a nation

- wide ecological risk assessment. However, in general terms, terrestrial ecosystems potentially at risk could include the treated field and immediately adjacent areas that may receive drift or runoff. Areas adjacent to the treated field could include cultivated fields, fencerows and hedgerows, meadows, fallow fields or grasslands, woodlands, riparian habitats, and other uncultivated areas.

Aquatic ecosystems potentially at risk include water bodies adjacent to or downstream from the treated site and might include impounded bodies such as ponds, lakes and reservoirs, or flowing waterways such as streams or rivers including all adja cent off

- channel habitats that are permanently or intermittently connected to flowing waters. For uses in coastal areas, aquatic habitat also includes marine ecosystems, including estuaries, embayments, and near shore environments.

### 23



## Risk Hypothesis

For a pesticide to pose an ecological risk, it must reach ecological receptors in biologically significant concentrations. An exposure pathway is the means by which a pesticide moves in the environment from a source to an ecological receptor. For an ecologica l pathway to be complete, it must have a source, a release mechanism, an environmental transport medium, a point of exposure for ecological receptors, and a feasible route of exposure.

A risk hypothesis describes the predicted relationship among the stressor, exposure, and assessment endpoint response along with the rationale for their selection. For rimsulfuron, the following ecological risk hypothesis is being employed for this national

- level ecological risk
assessment:

Rimsulfuron is mobile in s oil and toxic to plants and may pose a

risk to terrestrial plants near the site of application. Rimsulfuron is mobile and ha s been detected in aquatic systems. Therefore, rimsulfuron may also pose a risk to aquatic organisms. Toxicity studies suggest tha t this risk may be greatest to aquatic vascular plants.

The available data do not suggest that rimsulfuron is particularly toxic to aquatic or terrestrial animals. However, concentrations of the chemical in drinking water for birds and mammals may be of

concern due to the chemical’s high solubility

. Finally , the chemical's persistence and effect on aquatic and terrestrial plants could affect primary productivity and, in turn, have secondary effects on the entire animal community.



## Risk Hypothesis Descri ption

The environmental fate properties of rim sulfuron indicate that runoff, leaching, and spray drift represent potential transport mechanisms to aquatic and terrestrial organisms. The movement away from the site of application in turn represents exposure pathways for a broad range of biological rec eptors of concern (nontarget animals) and the potential attribute changes, i.e.

, effects such as reduced survival, growth and reproduction, in the receptors due to rim sulfuron exposure. Based on the nature of rim sulfuron ap plications which include aerial and ground application of rim sulfuron dispersible granules and solutions as well as rim sulfuron’s mobility in the environment, dietary and aquatic exposure from rim sulfuron applications will be assessed in the risk assessment. A preliminary evaluation is presented in this problem formulation on the applicability of rim sulfuron inhalation and drinking water exposure for terrestrial organisms to the risk assessment. Two models are used in this evaluation: SIP is used to address potential

### 24

adverse effects fr om drinking water exposure and STIR is used to address the same for inhalation exposure. These models and results are described below.


## Screening Imbibition Program (SIP)

The S creening I mbibition P rogram (SIP v.1.0, Released June 15, 2010) was used to cal culate an upper bound estimate of exposure using rim sulfuron’s solu bility (7,300 mg/L), the most sensitive
acute and chronic avian toxicity endpoint (>2,000 ppm; 1250 ppm, respectively ) and the most sensitive acute and chronic mammalian toxicity endpoints (>5,000 and 165 mg/kg

- bwt, respectively). Drinking water exposure alone was determined to be a potential pathway of concern for both mammalian and avian species on an acute and chronic basis for rim sulfuron. For a sample of the output generated by SIP v. 1.0, please see Appendix 3 . Detailed information about the SIP v.1.0, as well as the tool, can be found on the EPA’s website at http://www.epa.gov/pesticides/science/models_pg.htm#terrestrial

. While rimsulfuron exhibits low toxicity to avian and mammalian species, it is also high ly soluble. This high degree of solubility translates into potentially high concentrations in water th at animals may use as a source of drinking water. Yet use rates are very low, and so the likelihood of achieving the concentrations at the solubility limit is low. T his pathway will be explored further in the Ecological Risk Assessment for rimsulfuron pe nding the development of SIP v.2.0.


## Screening Tool for Inhalation Risk (STIR)

The S creening T ool for I nhalation R isk (STIR v.1.0, November 19, 2010) was used to calculate an upper bound estimate of exposure for rim sulfuron using the vapor pressure and mol ecular weight for vapor phase exposure as well as the maximum application rate and method of application for spray drift. STIR incorporates results from several toxicity studies including acute oral and inhalation rat toxicity endpoints obtained from the series of six guideline studies that are submitted to the Registration Division of the Office of Pesticide Programs for technical and formulated products of a pesticide (LD 50 

### > 5,000 mg/kg and LC 50 

### > 5.0 mg/L) as well as the most sensitive acute oral avian toxicity endpoint ( Mallard duck with LD 50 

### > 2,000 mg/kg). Based on the results of the STIR model, inhalation exposure alone was not determined to be a potential pathway of concern for either avian or mamm alian species on an acute basis.

Inhalation expos ure via spray drift and vapor

- phase of the pesticide alone does not appear to be of concern. The analysis of the inhalation route in STIR does not consider that aggregation with other exposure pathways such as dietary, dermal, or drinking water may contri bute to a total exposure that has a potential for effects to non

- target animals. However, the Agency does consider the relative importance of other routes of exposure in situations where data indicate that pesticide exposures through other routes may be p otentially significant contributors to wildlife risk (USEPA, 2004). The risk characterization section of the risk assessment will discuss the impact of consideration of other routes of exposure that have been identified as potentially important and the deg ree of certainty associated with screening

- level risk assessment conclusions. Detailed information about STIR v.1.0, as well as the tool, can be found on the EPA’s website at: http://www.epa.gov/pesticides/science/models_pg.htm#terrestrial . For a sample of the output generated by STIR v.1.0, please see Appendix 4

.

### 25



# Analysis Plan

In order to address the risk hypothesis, the potential for adverse effects on the environment is estimated. The use, environmental fate, and ecological effects of rim sulfuron are characterized and integrated to assess the potential for risks. This is acc omplished using a risk quotient (ratio of exposure concentration to effects concentration) approach ( Appendix 5 ) . Although risk is often defined as the likelihood and magnitude of adverse ecological effects, the risk quotient

based approach does not provi de a quantitative estimate of likelihood and/or magnitude of an adverse effect. However, as outlined in the Overview Document (USEPA 2004), the likelihood of effects to individual organisms from particular uses of rim sulfuron is estimated using the probit dose

- response slope and either the level of concern (discussed below) or actual calculated risk quotient values.

This analysis plan will be revisited and may be revised depending upon the information submitted by the public in response to the opening of the Registration Review docket for rim sulfuron.



## Stressors of Concern

Parent rimsulfuron and its three major degradates (IN

- 70941, IN

- 70942, and E9260) will be evaluated in the registration review risk assessment based on the potential for exposure in the aquatic and terrestrial environments. The risk assessment will therefore address the potential risk related to the parent alone as well as any concerns related to these major degradates by taking into consideration both exposure as well as the available toxicity data

.
While the current toxicity dataset shows that IN

- 70942 is of lower toxicity than the parent rimsulfuron to various taxa

, it is worth noting that the IN

- 70942 degradate in particular can be persistent in the environment

. Therefore, there is uncertainty as to the fate of IN

- 70942 in aquatic environments subject to run

- off following multiple years of applications of rimsulfuron. This potential persistence of IN

- 70942 will be further examined in the registration review risk assessment, as well as any implications for the characterization of risks related to rimsulfuron

use.

A n evaluation of environmental pesticide mixtures is beyond the scope of this assessment because of the myriad factors that cannot be quantified based on the available d ata. Those factors include identification of other possible co

- contaminants and their concentrations, differences in the pattern and duration of exposure among contaminants, and the differential effects of other physical/chemical characteristics of the re ceiving waters ( e.g. organic matter present in sediment and suspended water). Evaluation of factors that could influence additivity/synergism is beyond the scope of this assessment and the capabilities of the available data to allow for an evaluation. However, EFED acknowle dge s that not considering mixtures could over

- or under

- estimate risks depending on the type of interaction and factors discussed above. Given the limitations above, the final assessment will evaluate , characterize, and potentially make use of data availa ble on combinations of active ingredients with rim sulfuron, inert products, or environmental mixtures.

### 26



## Measures of Exposure

The measures of exposure will be estimated using models. Aquatic exposure for ecological effects will consist of aquatic EECs based on a total residue approach to include the parent rimsulfuron and the relevant degradate s, as well as parent alone, and derived using a water body that is vulnerable and representative of static ponds and first order waterways. Drinking water exposure wil l focus on the parent rimsulfuron alone. Terrestrial exposure will be estimated using a model that assumes direct application to a variety of avian, mammalian and reptilian food items. Exposure to terrestrial plants will be estimated using a model that as sumes rimsulfuron drifts or moves with runoff to adjacent habitats. For more information on the various models that will be used in the risk assessment see the links as outlined in Table 11

.

Table 11 . List of the various models and the related taxa for which the models will be used. Environment Concern Model Link

Aquatic Fish/

Invertebrates /Plants PRZM/EXAMS http://www.epa.gov/oppefed1/models/ water/

Human Health Drinking Water FIRST http://www.epa.gov/oppefed1/models/ water/first_v1_1_1_description.htm

SCI

- GROW http://www.epa.gov/oppefed1/models/

water/scigrow_description.htm

Terrestrial Animal T

- REX (dietary item /terrestrial invertebrate
contact ) http://www.epa.gov/oppefed1/models/t

errestrial/index.htm

SIP v2.0 (drinking water) Pending development

Plant TerrPlant (Run

- off) http://www.epa.gov/oppefed1/models/t errestrial/index.htm#terrplant AgDRIFT (Spray drift) http://www.agdrift.com/AgDRIFt2/Do

wnloadAgDrift2_0.htm AGDISP (Spray drift) http://www.continuum

dynamics.com/pr

- agdisp.html



## Measures of Effect

Assessment endpoints represent the actual environmental value that is to be protected, defined by an ecological entity (species, community, or other entity) and its attribute or characteristics (USEPA, 1998). For rimsulfuron, the ecological entities may include the following: birds, mammals, te rrestrial

- phase amphibians, reptiles, freshwater fish and invertebrates, aquatic

- phase amphibians, estuarine/marine fish and invertebrates, terrestrial plants, terrestrial invertebrates, and aquatic plants. The attributes for each of these entities includ e growth, reproduction, and survival.

### 27

Acute and chronic toxicity data from studies submitted by pesticide registrants along with the available open literature are used to evaluate the potential direct and indirect effects of rimsulfuron on aquatic and terrestrial receptors. This includes toxicity data on the technical grade active ingredient, degradates, and when available, formulated products. The open literature studies are identified using EPA’s ECOTOX database (USEPA 2007a), which employs a litera ture search engine for locating chemical toxicity data for aquatic life, terrestrial plants, and wildlife. ECOTOX is a source for locating single chemical toxicity data and potential chemical mixture toxicity data for aquatic life, terrestrial plants, and wildlife. ECOTOX was created and is maintained by the USEPA, Office of Research and Development, and the National Health and Environmental Effects Research Laboratory's Mid

- Continent Ecology Division. The evaluation of both sources of data can also prov ide insight into the direct and indirect effects of rimsulfuron on biotic communities from loss of species that are sensitive to the chemical and from changes in structure and functional characteristics of the affected communities. Where available, sublet hal effects observed in both registrant

- submitted and open literature studies will be evaluated qualitatively. Such effects have included behavioral changes ( e.g. , lethargy, changes in coloration and effects olfaction). Quantitative assessments of risks, though, are limited to those endpoints that can be directly linked to the Agency’s assessment endpoints of impaired survival, growth and reproduction. An updated report of the available studies contained within the ECOTOX database will be used for the fi nal risk assessment, and the studies will be evaluated according to guidance established for open literature studies (USEPA, 2011 b ). In the absence of data for either acute or chronic effects, the conservative assumption will be to presume that rimsulfuro n is toxic.

Consistent with the process described in the Overview Document (USEPA, 2004), the Agency has routinely relied on a surrogate species approach. Toxicological data generated from surrogate test species, which are intended to be representative o f broad taxonomic groups, have been used to extrapolate the potential effects on a variety of species (receptors) included under these taxonomic groups. For example, guideline data for freshwater fish have typically served as surrogates for aquatic

- phase amphibians and submitted studies for birds have served as surrogates for terrestrial

- phase amphibians and reptiles. For the purposes of Registration Review, the Agency will consider the best available data in an effort to provide additional refined endpoi nts for specified taxonomic groups for which guideline data on surrogate species are typically not available and large numbers of listed species occur. These taxa include aquatic

phase and terrestrial

- phase amphibians, freshwater mollusks, and reptiles. Based on an updated ECOTOX search, which will be conducted as part of the Registration Review preliminary risk assessment, EPA will consider both more and less sensitive endpoints for amphibians, freshwater mollusks, and reptiles, as compared to the regist rant

- submitted data for surrogate species ( i.e.

, freshwater fish are surrogates for aquatic

- phase amphibians, freshwater invertebrates are surrogates for freshwater mollusks, and birds are surrogates for terrestrial

- phase amphibians and reptiles) In situa tions where no additional open literature data are available to refine endpoints for amphibians, freshwater mollusks, and reptiles, the Agency will rely on registrant

- submitted data and open literature for surrogate test species, as specified above.

### 28



## Endan gered Species Assessments

Consistent with the Agency’s responsibility under the Endangered Species Act (ESA), the Agency will evaluate risks to Federally

- listed threatened and/or endangered species from registered uses of rimsulfuron. This assessment wil l be conducted in accordance with the Overview Document (USEPA 2004), provisions of the ESA, and the Services’ Endangered Species Consultation Handbook (USFWS/NMFS 1998)

.
The assessment of effects associated with registrations of rimsulfuron is based on an action area. The action area is considered to be the area directly or indirectly affected by the federal action, as indicated by the exceedance of Agency Levels of Concern (LOCs) used to evaluate direct or indirect effects. The Agency’s approach to d efining the action area under the provisions of the Overview Document (USEPA 2004) considers the results of the risk assessment process to establish boundaries for that action area with the understanding that exposures below the Agency’s defined LOCs const itute a no

- effect threshold. For the purposes of this assessment, attention will be focused on the footprint of the action ( i.e. , the area where rimsulfuron application occurs), plus all areas where offsite transport ( i.e. , spray drift, runoff, etc.) may result in potential exposure that exceeds the Agency’s LOCs. Specific measures of ecological effect that define the action area for listed species include any direct and indirect effects and/or potential modification of its critical habitat, including red uction in survival, growth, and reproduction as well as the full suite of sublethal effects available in the effects literature. Therefore, the action area extends to a point where environmental exposures are below any measured lethal or sublethal effect threshold for any biological entity at the whole organism, organ, tissue, and cellular level of organization. In situations where it is not possible to determine the threshold for an observed effect, the action area is not spatially limited and is assumed to be the entire United States.



# Preliminary Identification of Data Gaps

Table 12 and Table 13 identify environmental fate and eco

- toxicological studies , respectively, that offer data for each guideline requirement, as well as study classifications and whether or not further data are n eeded in order to support the risk assessment.



## Environmental Fate

Table 12 lists the status of the fate and transport data requirements for rim sulfu ron. The adequacy of the submitted data was evaluated relative to Agency guidelines.

### 29

Table 12

. Environmental fate data requirements for rimsulfuron and remaining data gaps.

Guideline Number Data Requirement MRID Study Classification Are more data needed?

830.7950 Vapor Pressure 41356301 Acceptable No

161

- 1 835.2120 Hydrolysis 41356333 Acceptable No

161

- 2 835.2240 Photodegradation in

Water 41931608 Acceptable No

161

- 3 835.2410 Photodegradation on

Soil 41931609 Acceptable No

162

- 1 835.4100 Aerobic Soil

Metabolism 41356334

48332003 Acceptable

In Review No (for first study)

TBD

162

- 2 835.4200 Anaerobic Soil

Metabolism 41356335 Acceptable No

162

- 4 835. 4300 Aerobic Aquatic

Metabolism 43288502

45490802 Supplemental

In Review TBD

162

- 3 835. 4200 Anaerobic Aquatic

Metabolism 48332004 In Review TBD

163

- 1 835.1240 Adsorption/Desorption 413563

- 36 Acceptable No

164

- 1 835.6100 Terrestrial Field

Dissipation 419316

- 06 419316

- 10 Acceptable No

165

- 4 850.1730 Fish Bio concentration No Study Submitted - No

### 30

Guideline Number Data Requirement MRID Study Classification Are more data needed?

164

- 1 835.6100 (supporti ng data) Environmental

Chemistry Methods in soil and water 41821701 43406701 43023101 43023102 43023103 43023104 43601701 Supplemental MRID #43023101 method for soil has been published at http://www.epa.gov/pestic ides/methods/ecmp2r.htm #R

. Yes, for rimsulfuron and data on the IN

- 70941, 70942 and E

- 9260 degradates

164

- 1 835.6100 (supporti ng data) Independent

Laboratory Validation (ILV) No study has been submitted - Yes, for rimsulfuron and data on the IN

- 70941, 70942, and E

- 9260 degradates



## Environmental Fate Data Gaps

The Agency has completed a review of all available data submitted by the registrant. Two studies that have previously been requested (see Rimsulfuron Ecological Risk Assessment dated 8/4/2009, DP Barcode D358867; page 5) are scientifically valid but additional data are still required:

Aerobic aq uatic metabolism (OPPTS guideline # 835.4300)

– A study has been submitted in response to a previously identified data gap and is currently under review. The data requirement will be considered unfulfilled until the study is fully reviewed and found eithe r acceptable or supplemental. Anaerobic aquatic metabolism (OPPTS guideline # 835.4400)

– A study has been submitted that is scientifically valid but additional characterization of secondary metabolites is requested.

Non

- Guideline Study: Environmental Chemistry Methods(EC Ms)/Independent Laboratory Validation(ILV): Rimsulfuron and Major Degradates

State of the art ECMs for trace residues in soil and water and ILVs are requested for rimsulfuron and its IN

- 70941, 70942, and E

- 9260 degradates . Environmen tal chemistry methods for soil and water are only available for parent rimsulfuron. In addition, no ILVs have been submitted to the Agency. Therefore, ECMs should be submitted and ILVs should be conducted for parent rimsulfuron studies in water and soil. The ECMs and ILVs should also include information and investigate the degradates IN

- 70941 and IN

- 70942 in both soil and water.

### 31



## Ecological Effects Data

For the ecological assessment, Table 13 lists the status of ecological data requirements for rimsulfuron. The following table presents a summary of identified data gaps and associated uncertainties.

Table 13

. Ecological effects data requirements for rimsulfuron and remaining data gaps.

Guideline # Data

Requirement Test

Substance MRID # or

Citation Study

Classification Is More Data Needed?

850.2100 Avian Oral LD 50 98.8% 25% (TEP) 98.8% 25% (TEP) 41356304

41931629 41931630 41931631 Acceptable

Acceptable Acceptable Supplemental No , a study is required for

avian passerine species based on the 40 CFR part 158 guidelines. However, no mortality or sublethal effects w ere found in any of the avian toxicity studie s at any concentration when tested with the TGAI

. A study on passerines with the TGAI is not needed for the risk assessment given the lack of toxicity.

850.2200 Avian Dietary

LC 50 98.8%

98.8% 25% (TEP) 25% (TEP) 41356305

41356306 41931632 41931633 Acceptable

Acceptable Supplemental Supplemental No

850.2300 Avian

Reproduction 99% 43277201 Acceptable No; only one study was submitted on Bobwhite quail even though two are required by the 40CFR part 158 guidelines. However, rimsulfuron does not appear to be toxic to avian species on either an acute or chronic basis, therefore this study would add little information to the risk assessment

.

850.1075 Freshwater Fish

Acute LC 50 98.8% 41356307 41356308 41931620 Acceptable

Acceptable In Review No

### 32

Guideline # Data

Requirement Test

Substance MRID # or

Citation Study

Classification Is More Data Needed?

850.1010 Freshwater

Invertebrate Acute LC 50 98.8% 41356309 41931621 Acceptable

Supplemental No

850.1075 Estuarine/Marine

Fish Acute LC 50 99% 42471303 Acceptable No

850.1025 Estuarine/Marine

Mollusk Acute EC 50 99% 42471301 Acceptable No

850.1035 850.1045 850.1055 Estuarine/Marine

Shrimp Acute EC 50 99% 42471302 Acceptable No

850.1400 Freshwater Fish

Early Life

- Stage 25% ( TEP )

99% 98.8% 43472703

43472704 43472705 In Review Yes, data have been submitted but are in review. Request of additional data will be pending the outcome of the formal review of these studies.

850.1400 Estuarine/Marine

Fish Early Life

Stage No Data Submitted Yes, the exposure pathway is complete for saltwater fish. This t oxicity study may be waived pending the review of freshwater fish ELS data.

850.1300 Aquatic

Invertebrate Life

Cycle (freshwater) 98.8%

25% ( TEP ) 43472701

43472702 In Review Yes, data have been submitted but are in review. Request of additional data will be pending the outcome of the formal review of these studies.

850.1350 Aquatic

Invertebrate Life

Cycle (marine) No Data Submitted Yes, the exposure pathway is complete for saltwater invertebrates. This
t oxicity study may be waived pending the review of freshwater invertebrate lifecycle data.

### 33

Guideline # Data

Requirement Test

Substance MRID # or

Citation Study

Classification Is More Data Needed?

850.1500 Fish Full Life

Cycle No Data Submitted No, there is no information to indicate that rimsulfuron or any of its degradates will be toxic enough on a chronic basis
to trigger the request specifically for a fish full life

- cycle study

850. 4100 Seedling

Emergence (Tier I) 98.8% TGAI

98.1% TGAI 42471304

43539201 Supplemental

(tomato) No

850.4 100 Seedling

Emergence (Tier II) 98.8% TGAI

98.1% TGAI 42471304

43539201 Supplemental

(rape, onion

, sugar beet, wheat, soybean, sorghum, pea, cucumber) Yes, these studies used the

TGAI. However, the use of a TEP is required . In addition, NOAEL values were not determined for the most sensitive species. Tier II seedling emergence studies should be conducted for 6 dicots and 4 monocots with a TEP.

850.41 50 Vegetative Vigor

(Tier II) 98.8% TGAI

98.1% TGAI 42471304

43539201 Supplemental

(soybean, rape, sugarbeet

, onion, wheat, sorghum, tomato, cucumber, pea) Yes, these studies used the

TGAI. However, the use of a TEP is required. In addition, NOAEL values were not determined for the most sensitive species. Tier II vegetative vigor studies should be conducted for 6 dicots and 4 monocots with a TEP.

Non

guideline Terrestrial Plant

reproduction toxicity No Data Submitted No a

850.4400 Aquatic Plant

Growth : Vascular (Tier II) 98.57% 42471308 Acceptable No

### 34

Guideline # Data

Requirement Test

Substance MRID # or

Citation Study

Classification Is More Data Needed?

850.5400 Aquatic Plant

Growth: Non

Vascular (Tier I) 98.57%

98.57% 98.57% 98.8% 42471305

42471306 42471307 43043601 Acceptable

Acceptable Acceptable Acceptable No , the studie s provide

NOAEC values, and the

non

- definitive EC 50 values are an order of magnitude greater than previously modeled EECs. However, if use rates increase then the need for non

- vascular aquatic plants will be re

evaluated.

850.3020 Honey Bee Acute

Contact LD 50 98.8% 41356331 Acceptable No

870.1100 Acute Oral

Toxicity to Rat 25% (TEP)

98.8% 25% (TEP) 25.7% (TEP) 41356311

41356310 41931634 47091007 Acceptable

Acceptable Acceptable Acceptable No

870.1300 Acute Inhalation

Toxicity to Rat 98.8%

26.5% (TEP) 25% (TEP) 98.6% 41356314

41931625 41931637 41931636 Acceptable

Acceptable Acceptable Acceptable No

870.3800 Mammalian

Reproduction

-- Rat 98.8% 41931644 Acceptable No

a EFED's Plant Technical Team (PTT) conducted an analysis of available SU plant reproduction data from the open literature and the registrant

- submitted data for chlorsulfuron and concluded that data from the 850.4150 vegetative vigor guideline study are sufficient ly protective of potential impacts to plant reproduction. Acetolactate synthase (ALS) inhibitors primarily affect metabolically

- active meristem tissues. When plants are exposed at a young, vigorously growing life

- stage, effects are expressed primarily as i nhibition of vegetative growth ( i.e. biomass, shoot length). As plants mature these effects are less pronounced. However, as plants enter their reproductive life

- stage, the metabolically

- active tissue will include flower and seed production. Plants expo sed to SU herbicides during the reproductive life stage are likely to exhibit adverse effects on reproduction, generally expressed as reduced seed number or reduced seed weight. Based on the latest data analysis, these effects are expected to occur at sim ilar concentrations to those effects determined in the guideline vegetative vigor studies (850.4150) so further data are not requested at this time.



# References

USDA, 2006

- 2010. NASS Crop Reporting Districts. Online: http://www.ers.usda.gov/briefing/arms/resourceregions/resourceregions.htm#nass

.

### 35

USDA, 2007. Census of Agriculture. Online: http://www.agcensus.usda.gov/Publications/2007/index.asp

USEPA. 1998. Guidelines for Ecological Risk Assessment. Risk Assessment Forum, Office of Research and Development, Washington, D.C. EPA/630/R

- 95/002F. April 1998. http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=30759

USEPA . 2004. Overview of the Ecological Risk Assessment Process in the Office of Pesticide Programs. U.S. Environmental Protection Agency, Office of Prevention, Pesticides and Toxic Substances, Office of Pesticide Programs, Washington DC. January 23, 2004.

USEPA. 2007a. Ecotoxicology (ECOTOX) database. Version 4. Office of Research and Development (ORD) , and the National Health and Environmental Effects Research Laboratory's (NHEERL's) Mid

- Continent Ecology Divisio n (MED)

. http://cfpub.epa.gov/ecotox/ecotox_home.cfm

USEPA . 2007b. Ecological Incident Information System (EIIS). Environmental Fate and Effects Division.

USEPA. 2007c. 40 CFR Part 158. Pe sticides; Data Requirements for Conventional Chemicals: Final Rule. 72 FR 60934. October 26, 2007.

USEPA . 201 1 a

. Screening Level Estimates of Agricultural Uses on Rim sulfuron . Biological and Economic Assessment Division, Office of Pesticide Programs. Dated October 31

, 201 1

.

USEPA. 2011 b . Guidance for the evaluation of open literature. U.S. Environmental Protection Agency, Office of Prevention, Pesticides and Toxic Subst ances, Office of Pesticide Programs, Washington DC. May 16, 2011.

U.S. Fish and Wildlife Service (USFWS) and National Marine Fisheries Service (NMFS). 1998. Endangered Species Consultation Handbook: Procedures for Conducting Consultation and Conferenc e Activities Under Section 7 of the Endangered Species Act. Final Draft. March 1998.

### 36



# APPENDIX 1 . Submitted Environmental Fate and Effects Studies

SUBMITTED FATE STUDIES: 9/8/11

161

- 1 Hydrolysis

MRID Citation Reference

41356333 Horne, P.; Boucher, C. (1989) Hydrolysis of [Pyridine

- 2

- Cardon 14] DPX

E9636 and [Pyrimidine

- 2

- Carbon 14]DPX

- E9636 in Buffer Solu

- tions of 5, 7, and 9: Lab Project Number: AMR

- 1221

- 88. Unpub

- lished study prepared by E. I. du Pont de Nemours & Co., Inc. 4 6 p.



### 161

- 2 Photodegradation

- water

MRID Citation Reference

41931608 Horne, P.; Boucher, C. (1989) Photodegradation of ?Pyridine

- 2

- 14C| DPX

- E9636

and ?Pyrimidine

- 2

- 14C| in Water(Conducted in Sunlight) : Lab Project Number: AMR

- 1220

- 88. Unpublished study prepared by E. I. du Pont de Nemours and Co. 59 p.

Naidu, M.V. 1993. Response to EFQB CamMts. Submitted by du Pcnt at the request of EFGWB reviewer Nov. 18, 1993



### 161

- 3 Photodegradation

- soil

MRID Citation Reference

41931609 Brown, A.; Young, G. (1989) Photodegradation of ?Pyridine

- 2

- 14C|DPX

- E9636

and ?Pyrimidine

- 2

- 14C|DPX

- E9636 on Soil: Lab Project Num

- ber: AMR

- 1219

- 88. Unpublished study prepared by E. I du Pont de Nemours and Co. 54 p.

Naidu, M.V. 1993. Additional infonm tion requested by 

### m during the review process of the 162

- 3 study. Suhitted t a letter f m D. Drane, du Pont ; 11/16/93



### 162

- 1 Aerobic soil metabolism

MRID Citation Reference

41356334 Naidu, M. (1989) Aerobic Soil Metabolism of [Pyridine

- 2

- carbon 14] DPX

E9636 and [Pyrimidine

- 2

- carbon 14]DPX

- E9636: Lab Project Number: AMR

1218

- 88. Unpublished study prepared by E. I. du Pont de Nemours and Co., Inc. 49 p.

45490802 Trabue, S.; Lydick, T. (2001) Degradation of Rimsulfuron in Two Water

### 37 Sediment Systems: Lab Project Number: DUPONT

- 3980: 3980. Unpublished study prepared by E.I. du Pont de Nemours and Company. 97 p.



### 162

- 2 Anaerobic soil metabolism

MRID Citation R eference

41356335 Naidu, M.; Fogiel, A. (1989) Anaerobic Soil Metabolism of [Pyri

- dine

- 2

- carbon

14]DPX

- E9636 and [Pyrimidine

- 2

- carbon 14]DPX

- E9636 Laboratory Project Number: AMR

- 1217

- 88. Unpublished study pre

- pared by E. I. du Pont de Nemours and Co., Inc. 53 p.



### 162

- 4 Aerobic aquatic metab.

MRID Citation Reference

43288502 Naidu, M. (1991) Aerobic Aquatic Metabolism of (Pyridine

- 2

- (carbon 14)) DPX

E9636 and (Pyrimidin

- 2

- (carbon 14)) DPX

- E9636: Lab Project Number: AMR/1407/89. Unpublished study prepared by E.I. du Pont de Nemours and Co. 76 p.



### 163

- 1 Leach/adsorp/desorption

MRID Citation Reference

41356336 Naidu, M. (1989) Batch Equilibrium (Adsorption/Desorption) Studies of DPX

E9636: Lab Project Number: AMR

- 1204

- 88. Unpublished study prepared by E. I. du Pont de Nemours & Co., Inc. 38 p.

41356337 Naidu, M.; Fogiel, A. (1989) Soil Mobility of DPX

- E9636 and Its Soil

Degradates by Soil TLC: Lab Project Number: AMR

- 1327

- 88. Unpublished study prepared by E. I. du Pont de Nemours & Co., Inc. 21 p.

44448101 Warren, R. (1997) Monitoring for Rimsulfuron in Leachate from Field

Lysimeters Treated with Basis Herbicide: Lab Project Number: AMR 3417

- 95: 008

- 017. Unpublished study prepared by E.I. du Pont de Nemours and Co., Lancaster Labs. and Centre Analytical Labs., Inc. 86 p.



### 1 64

- 1 Terrestrial field dissipation

MRID Citation Reference

41931606 Naidu, M. (1991) Field Soil Dissipation Study of ?Pyridine

- 2

- 14C| DPX

- E9636

and ?Pyrimidine

- 2

- 14C|DPX

- E9636: Lab Project Number: AMR

- 1451

- 89. Unpublished study prepared by E. I du Pont de Nem

- ours and Co. 142 p.

41931610 Naidu, M. (1990) Field Soil Dissipation Study of ?Pyridine

- 2

- 14C| DPX

- E9636

and ?Pyrimidine

- 14C|DPX

- E9636 at Newark, Delaware: Lab Project Number: AMR

- 1225

- 88. Unpublished study prepared by E. I du Pont de Nemours and Co. 51 p.

### 38 Review of rimsulfuron fie ld dissipation and column lysimeter study protocols



### 165

- 1 Confined rotational crop

MRID Citation Reference

41356338 Schneiders, G. (1989) Confined Accumulation Study of DPX

- E9636 on

Rotational Crops: Lab Project Number: AMR

- 1187

- 88. Unpublish

- ed study prepared by E. I. du Pont de Nemours and Co., Inc. 60 p.

41931607 Schneiders, G. (1989) Confined Accumulation Study of DPX

- E9636 on

Rotational Crops: Lab Project Number: AMR

- 1187

- 88. Unpublished study prepared by E. I. du Pont de Nemours and Co. 63 p.



### 165

- 4 Bioaccumulation in fish

MRID Citation Reference

41356339 Lee, P. (1989) Fish Accumulation Potential for DPX

- E9636: Lab Pro

- ject

Number: AMR

- 1561

- 89. Unpublished study prepared by E. I. du Pont de Nemours & Co., Inc. 13 p.



### ECM Methods

41821701 Proksch, L.R. and M.P, Wadsley (1989) Residue Method for Extraction and

HPLC Analysis of Harmony Herbicide from Soil Matrices. Performed and Submitted by Du Pont. AMR

- 1550

- 89. Completed 11/17/89 and Reformatted 3/18/91.

43406701 Batelle (1988) (Columbus, OH) Method for the Determination of Chlorsulfuron,

DPX

- A7881, DPX

- L5300, DPX

- M6316 and Metsulfuron Methyl in Groundwater. Du Pont Report 1335

- 88. Completed 11/21/88, Revised 6/21/91.

43023101 Amoo, J. (1993) Analytical Method for the Quantitation of DPX

- E9636 in Soil by

Liquid Chromatography: Lab Project Number: AMR 2231

- 91. Unpublished study prepared by E.I. du Pont de Nemours and Co., DuPont Agricultural Products. 68
p.

43023102 Shalaby, L.; Bramble, F. (1990) Thermospray LC/MS Analytical Method for the

Quantitation of DPX

- 79406 and Metabolites in Soil: Lab Project Number: AMR

1509

- 89. Unpublished study prepared by E.I. du Pont de Nemours and Co., DuPont Agricultural Products. 35 p.

43023103 Zahnow, E.; Orescan, D. (1991) Analytical Method for the Determination of

E9636 and V9360 in Water by HPLC: Lab Project Number: AMR

- 2186

- 91. Unpublished study prepared by E.I. du Pont de Nemours and Co., DuPont Agricultural Products. 20 p.

43023104 Zahnow, E.; Orescan, D. (1992) Analytical Method for the Determination of

E9636 in Water by HPLC: Lab Project Number: AMR 2210

- 91. Unpublished study prepared by E.I. du Pont de Nemours and Co., DuPont Agricultural Products. 20 p.

### 39

43601701 

### Valida tion of Immunoassay Methods (Soil; Water)

Du Pont Report No. AMR 2438

- 92, "An Enzyme

- Linked Immunoassay (ELISA) Method for .the Determination of Residues of Sulfonylureas in Water and Soilff (.

- #43601701)



### Non Guideline Selections

43288503 Naidu, M. (1991) DPX

- E9636 Environmental Fate and Residue Monograph: Lab

Project Number: AMR/2131/91. Unpublished study prepared by E.I. du Pont de Nemours and Co. 32 p.

43396501 Russel, M. (1994) Estimated Environmental Concentrations of Rimsulfuron and

Competitive Corn Herbicides in Ground Water and Surface Water in the USA: Lab Project Number: 423/09/05: 3064/94. Unpublished study prepared by Blasland, Bouck & Lee, Inc. 45 p.

44186701 McCooey, K. (1996) Magnitude of Residues of Rimsulfuron in Soil Fo llowing

Application of DPX

- E9636 at Maximum Label Rates: Lab Project Number: AMR 3404

- 95. Unpublished study prepared by Dupont Agricultural Products. 197 p.

47702504 Leva, S.; Rardon, P. (2001) Summary of Herbicide Screening Data for Major

Metabolites of Rimsulfuron. Project Number: DUPONT/6787. Unpublished study prepared by E.I. du Pont de Nemours and Company. 13 p.

48106102 LeNoir, J. (2003) South Dakota Surface Water Monitoring of Sullfonylureas,

Summer 2003. Project Number: DUPONT/13166, ML03/1080/DUP. Unpublished study prepared by Morse Laboratories, Inc. 145 p.

43288501 Naidu, M.V. and Hershberger (1992) Environmental and Toxicological

Assessment of DPX

- E9636 Metabolites. Performed by E.I. du Pont de Nemours and Comp

- any, Du Pont Agricu ltural Products, Wilmington, DE Laboratory Project ID AMR 2268

- 91, Completed 1/21/92.

43406702 Ibid. Supplement to Report. Performed by Batelle, Frankfurt.

1994 Fate Database Oneliner report

### 40

SUBMITTED EFFECTS STUDIES: Revised August 16, 2011 71

- 1 Avian Single Dose Oral Toxicity

MRID Citation Reference

41356304 Grimes, J.; Jaber, M. (1988) An Acute Oral Toxicity Study with the Bobwhite: H

# 17,463: Final Report: Lab Project Number: 112

- 208; 797

- 88. Unpublished study prepared by Wildlife International Ltd. 19 p.

41931629 Culotta, J.; Campbell, S.; Hoxter, K.; et al. (1990) An Acute Oral Toxicity Study

with the Mallard: H #18,231: Lab Project Number: 112

- 239: 363

- 90. Unpublished study prepared by Wildlife Inter

- national Ltd. 18 p.

41931630 Culotta, J.; Campbell, S.; Hoxt er, K.; et al. (1990) An Acute Oral Toxicity Study

with the Mallard: H #17,463: Lab Project Number: 12

- 232: 411

- 90. Unpublished study prepared by Wildlife Interna

- tional Ltd. 18 p.

41931631 Culotta, J.; Hoxter, K.; Smith, G. (1990) An Acute Oral Toxicit y Study with the

Northern Bobwhite: H #18,231: Lab Project Number: 112

- 238: 364

- 90. Unpublished study prepared by Wildlife Inter

- national Ltd. 18 p.



### 71

- 2 Avian Dietary Toxicity

MRID Citation Reference

41356305 Grimes, J.; Jaber, M. (1989) A Dietary LC50 Study with the Bobwhite H

#17,463: Lab Project Number: 112

- 206. Unpublished study prepared by Wildlife International Ltd. 27 p.

41356306 Grimes, J.; Jaber, M. (1989) A Dietary LC50 Study with the Mallard: H # 17,463:

Lab Project Number: 112

- 207: 17

- 89. Unpublished study prepared by Wildlife International Ltd. 27 p.

41931632 Driscoll, C.; Foster, J.; Hoxter, K. et al. (1990) A Dietary LC50 Study with the

Northern Bobwhite: H #18,231: Lab Project Number: 112

- 236: 487

- 90. Unpublished study prepared by Wildlife Inter

- national Ltd. 25 p.

41931633 Driscoll, C.; Foster, J.; Hoxter, K. et al. (1990) A Dietary LC50 Study with the

Mallard: H #18, 231: Lab Project Number: 112

- 237: 486

- 90. Unpublished study prepared by Wildlife International Ltd. 27 p.



### 71

- 4 Avian Reproduction

MRID Citation Reference

42835801 Beavers, J.; Trumbull, S.; Grimes, J.; et al. (1993) H

- 17,463: A Pilot

Reproduction Study with the Northern Bobwhite (Colinus virginianus): Lab Project Number: 112

- 336: 428

- 93. Unpublished study prepared by Wildlife International, Ltd. 69 p.

43277201 Beavers, J.; Foster, J.; Mitchell, L. et al. (1994) H

- 17,463 (Rimsulfuron): A One

Generation Reproduction Study with the Northern Bobwhite (Colinus virginianus): Lab Project Number: 112/337: 257/94: HLO/257/94. Unpublished

### 41 study prepared by Wildlife Intern ational, Ltd. 246 p.



### 72

- 1 Acute Toxicity to Freshwater Fish

MRID Citation Reference

41356307 Hutton, D. (1989) Static Acute 96

- Hour LC50 of DPX

- E9636

- 22 to

Rainbow Trout (Salmo gairdneri): Lab Project Number: 351

- 89: 4581

- 660. Unpublished study prepared by E. I. du Pont de Ne

- mours and Co., Inc., Haskell Laboratory for Toxicology and Industrial M edicine. 18 p.

41356308 Hutton, D. (1989) Static Acute 96

- Hour LC50 of DPX

- E9636

- 22 to Bluegill

Sunfish (Lepomis macrochirus): Lab Project Number: 352

- 89: 4581

- 660. Unpublished study prepared by E. I. du Pont de Nemours and Co., Inc., Haskell Laboratory for Toxicology and Industrial Medicine. 18 p.

41931620 Hutton, D. (1989) Static Acute 96

- Hour LC50 of DPX

- E936

- 22 to Blue

- gill

Sunfish (Lepomis macrochirus): Lab Project Number: 4581

- 660 : 352

- 89. Unpublished study prepared by E. I. du Pont de Nemou

- r s and Co. 18 p.

43472706 Baer, K. (1991) Static, Acute, 96

- Hour LC50 of IN E9636

- 37 to Rainbow

Trout (Oncorhynchus mykiss): Lab Project Number: MR

- 4581

- 794: 710

- 90: HLR 710

- 90. Unpublished study prepared by DuPont Haskell Lab for Toxicology and Industria l Medicine. 20 p.

47702502 Kreamer, G. (1993) Static, Acute, 96

- Hour LC50 of IN

- 70942

- 4 to Rainbow

Trout, Oncorhynchus mykiss. Project Number: 9581/042, 85/93. Unpublished study prepared by E.I. du Pont de Nemours and Company. 27
p. IN

- 70942

- 4 = Dual active mixture 129002+629009



### 72

- 2 Acute Toxicity to Freshwater Invertebrates

MRID Citation Reference

41356309 Hutton, D. (1989) Static Acute 48

- Hour EC50 of DPX

- E9636

- 22 to Daphnia

magna: Lab Project Number: 350

- 89: 4581

- 660. Unpub

- lished study prepared by E. I. du Pont de Nemours and Co., Inc., Haskell Laboratory for Toxicology and Industrial Medicine. 18 p.

41931621 Baer, K. (1990) Static Acute 48

- Hour EC50 of IN E9636

- 22 to Fed Daphnia

magna: Lab Project Number: 26

- 90: MR

- 4581

- 677. Unpubli

- shed study prepared by E. I. du Pont de Nemours and Co. 13 p.

47702505 Pierson, K. (1991) Static, Acute, 48

- Hour EC50 of IN 70942

- 2 to Daphnia

magna. Project Number: 113/91, MR/4581/839, 18404. Unpublished study prepared by E.I. du Pont de Nemours and Company. 19 p.



### 72

- 3 Acute Toxicity to Estuarine/Marine Organisms

MRID Citation Reference

42471301 Graves, W. ; Swigert, J. (1992) DPX

- E9636

- 22: A 96

- Hour Shell Deposition Test

### 42 with the Eastern Oyster (Crassostrea virginica): Lab Project Number: 112A

- 104: 542

- 92. Unpublished study prepared by Wildlife International Ltd. 34 p.

42471302 Graves, W.; Swigert, J. (1992) DPX

- E9636

- 22: A 96

- Hour Flow

- Through Acute

Toxicity Test with the Salt Water Mysid (Mysidopsis bahia): Lab Project Number: 112A

- 105: 544

- 92. Unpublished study prepared by Wildlife International Ltd. 32 p.

42471303 Graves, W .; Swigert, J. (1992) DPX

- E9639

- 22: A 96

- Hour Flow

- Through Acute

Toxicity Test with the Sheepsheed Minnow (Cyprinodon variegatus): Lab Project Number: 112A

- 103: 543

- 92. Unpublished study prepared by Wildlife International Ltd. 32 p.



### 72

- 4 Fish Earl y Life Stage/Aquatic Invertebrate Life Cycle Study

MRID Citation Reference

43472701 Baer, K. (1990) Chronic Toxicity of IN E9636

- 22 to Daphnia magna: Revision

No. 1: Lab Project Number: 95

- 90: MR

- 4581

- 677: HLR 95

- 90. Unpublished study prepared by DuPont Haskell Lab for Toxicology and Industrial Medicine. 423 p.

43472702 Baer, K. (1991) Chronic Toxicity of IN E9636

- 37 to Daphnia magna: Lab Project

Number: 134

- 91: MR

- 4581

- 794: HLR 134

- 91. Unpublished study prepared by DuPont Haskell Lab for Toxicology and Industrial Medicine. 54 p.

43472703 Baer, K. (1991) Flow

- through, 2 1

- Day Toxicity of DPX

- E9636

- 40 (25DF) to

Rainbow Trout (Oncorhynchus mykiss): Revision No. 1: Lab Project Number: 135

- 91: MR

- 4581

- 869: HLR 135

- 91. Unpublished study prepared by DuPont Haskell Lab for Toxicology and Industrial Medicine. 32 p.

43472704 Kre amer, G. (1994) Early Life

- stage Toxicity of DPX

- E9636

- 22 (Rimsulfuron)

with Rainbow Trout, Oncorhynchus mykiss: Lab Project Number: 9895

- 001: HLR 507

- 94: 507

- 94. Unpublished study prepared by DuPont Haskell Lab for Toxicology and Industrial Medicine. 515 p.

43472705 Hutton, D. (1991) Flow

- through, 21

- Day Toxicity of DPX

- E9636

- 22 to Rainbow

Trout, Oncorhynchus mykiss: Revision No. 1: Lab Project Number: MR

- 4581

- 848: 672

- 91: HLR 672

- 91. Unpublished study prepared by DuPont Haskell Lab for Toxicology and Industrial Medic ine. 37 p.

45490801 Samel, A. (2001) IN

- JF999: 21

- Day Chronic, Static

- Renewal Toxicity to Daphnia

magna: Lab Project Number: 13694: 254: DUPONT

- 6024. Unpublished study prepared by E.I. du Pont de Nemours and Company. 61 p. {OPPTS 850.1300}



### 122

- 1 Seed Germination/Seedline Emergence and Vegetable Vigor

MRID Citation Reference

42471304 McKelvey, R; Kuratle, H. (1992) Infuence of Rimsulfuron on Seed Germination,

Seedling Emergence, and Vegetative Vigor of Several Terrestrial Plants: Lab Project Number: AMR 2074

- 91. Unpublished study prepared by E. I. du Pont de Nemours and Co. 230 p.

42471308 Hoberg, J. et al. (1992) Acute Toxicity of DPX

- E9636 to Lemna gibba G3: Lab

### 43 Project Number: 92

- 4

- 4236: 97.0991.6128.410. Unpublished study prepared by Springborn Laboratories Inc. 62 p.

43539201 McKelvey, R. (1994) Influence of Rimsulfuron on Se ed Germination, Seedling

Emergence, and Vegetative Vigor of Several Terrestrial Plants: Supplement No. 1: Lab Project Number: AMR 2074

- 91: HA

- 94

- 067. Unpublished study prepared by DuPont Agricultural Products; and Haskell Lab for Toxicology and Industrial Medicine (DuPont). 118 p.



### 122

- 2 Aquatic plant growth

MRID Citation Reference

42471305 Hughes, J. (1992) DPX

- E9636: Toxicity to Selenastrum capricornutum: Lab

Project Number: B382

- 153

- 1: AMR

- 2316

- 92. Unpublished study prepared by malcolm Pirnie Inc. 51 p.

42471306 Hughes, J. (1992) DPX

- E9636: Toxicity to Anabaena flos

- aquae: Lab Project

Number: B382

- 153

- 2: AMR 2317

- 92. Unpublished study prepared by Malcolm Pirnie Inc. 51 p.

42471307 Hughes, J. (1992) DPX

- E9636: Toxicity to Navicula pelliculosa: Lab Project

Number: B382

- 153

- 3: AMR 2318

- 92. Unpublished study prepared by Malcolm Pirnie Inc. 51 p.

42711601 Feddersen, P. (1993) IN 70942

- 4 Metabolite Algal Growth Inhibition: Lab

Project Number: DPC 17/930307. Unpublished study prepared by Huntingdon Research Centre, Lt d. 22 p.

43043601 Thompson, S. (1993) RIMSULFURON (DPX

- E9636): Influence on Growth and

Reproduction of Skeletonema costatum: Lab Project Number: AMR 2769

- 93: 112A

- 120. Unpublished study prepared by Wildlife International Ltd. and DuPont Agricultural Prod ucts. 33 p.



### 123

- 1 Seed germination/seedling emergence and vegitative vigor

MRID Citation Reference

42471304 McKelvey, R; Kuratle, H. (1992) Infuence of Rimsulfuron on Seed Germination,

Seedling Emergence, and Vegetative Vigor of Several Terrestrial Plants: Lab Project Number: AMR 2074

- 91. Unpublished study prepared by E. I. du Pont de Nemours and Co. 230 p.

43539201 McKelvey, R. (1994) Influence of Rimsulfuron on Seed Germination, Seedling

Emergence, and Vegetative Vigor of Several Terrestrial Plants: Supplement No. 1: Lab Project Number: AMR 2074

- 91: HA

- 94

- 067. Unpublished study prepared by DuPont Agricultur al Products; and Haskell Lab for Toxicology and Industrial Medicine (DuPont). 118 p.

43683001 McKelvey, R. (1995) Influence of Rimsulfuron on Seed Germination, Seedling

Emergence and Vegetative Vigor of Several Terrestrial Plants: Revision No. 1: Lab Pro ject Number: AMR 2074

- 91. Unpublished study prepared by DuPont Agricultural Products. 230 p.

47702506 Porch, J. (2001) In

- E9260: A Greenhouse Study to Investigate the Effects on

### 44 Seedling Emergence and Growth of Two Sensitive Terrestrial Plants Following Soil Exposure . Project Number: DUPONT/6647, 112/504. Unpublished study prepared by Wildlife International Ltd. 42 p.

47702507 Porch, J. (2001) IN

- 70942: A Greenhouse Study to Investigate the Effects on

Seedling Emergence and Growth of Two Sensitive Terre strial Plants Following Soil Exposure. Project Number: DUPONT/6648, 112/505. Unpublished study prepared by Wildlife International Ltd. 41 p.

47702508 Porch, J. (2001) IN

- 70941: A Greenhouse Study to Investigate the Effects on

Seedling Emergence and Growth of Two Sensitive Terrestrial Plants Following Soil Exposure. Project Number: DUPONT/6649, 112/506. Unpublished study prepared by Wildlife International Ltd. 42 p.



### 123

- 2 Aquatic plant growth

MRID Citation Reference

42471308 Hoberg, J. et al. (1992) Acute Toxicity of DPX

- E9636 to Lemna gibba G3: Lab

Project Number: 92

- 4

- 4236: 97.0991.6128.410. Unpublished study prepared by Springborn Laboratories Inc. 62 p.

42711601 Feddersen, P. (1993) IN 70942

- 4 Metabolite Algal Growth Inhibition: Lab

Project Number: DPC 17/930307. Unpublished study prepared by Huntingdon Research Centre, Ltd. 22 p.

47702510 Sloman, T. (2000) IN

- 70942: Influence on Growth Rate of Green Alga

Selena strum capricornutum. Project Number: DUPONT/3743, 13208, 280. Unpublished study prepared by E.I. du Pont de Nemours and Company. 40 p.

48085001 Douglas, M.; Halls, R. (1992) DPX

- E9636

- 22 Technical: An Assessment of the

Inhibitory Effect on the Growth of D uckweed (Lemna minor). Project Number: DPT/186/E/920708. Unpublished study prepared by Huntingdon Research Centre, Ltd. 20 p.

47702511 Softcheck, K. (2008) IN

- E9260: 7

- Day Toxicity Test with Duckweed (Lemna

gibba). Project Number: 26572, 97/6431, 17979. U npublished study prepared by Springborn Smithers Laboratories. 61 p.

47702512 Softcheck, K. (2008) IN

- 70941: 7

- Day Toxicity Test with Duckweed (Lemna

gibba). Project Number: 26573, 17980, 328. Unpublished study prepared by Springborn Smithers Laboratories . 66 p.

47702509 Sloman, T.L. 1996. IN

- 70942 (Metabolite ofDPX

- E9636): Influence on Growth and

Reproduction of Lemna gibba G3. Unpublished study performed by E.!. du Pont de Nemours and Company, DuPont Stine

- Haskell Research Center, Newark, Delaware. Labo ratory Project ID: AMR 4060

- 96 and MR 11011. Study sponsored by E.!. du Pont de Nemours and Company, Wilmington, Delaware. Study completed December 4, 1996.



### 141

- 1 Honey bee acute contact

MRID Citation Reference

41356331 Hoxter, K.; Jaber, M. (1989) An Acute Contact Toxicity Study with the Honey

Bee: H # 17,463: Lab Project Number: 112

- 216: 267

- 89. Unpublished study

### 45 prepared by Wildlife International Ltd. 15 p.



### 885.4150 Wild mammal testing, Tier I

MRID Citation Re ference

47260101 McGaughey, B.; Rives, A.; Dressel, S.; et al. (2007) NatureServe Data Evaluation

and Review. Project Number: 06763. Unpublished study prepared by Compliance Services International. 78 p.



### 885.4750 Aquatic ecosystem test

MRID Citation Reference

47260101 McGaughey, B.; Rives, A.; Dressel, S.; et al. (2007) NatureServe Data Evaluation

and Review. Project Number: 06763. Unpublished study prepared by Compliance Services International. 78 p.



### 850.1790 Chironomid Sediment Toxicity Test

MRID Citation Reference

47702503 Krueger, H.; Thomas, S.; Kendell, T. (2003) IN

- 70942: A Prolonged Sediment

Toxicity Test with Chironomus Riparius Using Spiked Sediment. Project Number: 12329, 14625, 1539. Unpublished study prepared by Wildlife International Ltd. 66 p.



### Non Target Beneficial Insect Toxicity

44217701 Candolfi, M. (1996) DPX

- KX710 in Mixture with IN

- KG691 Surfactant:

Laboratory Contact Toxicity Test with the Predacious Mite, Typhlodromus pyri Scheuten (Acari: Phytoseiidae), Based on the IOBC Approved Method of Overmeer (1988): Final Report: Lab Project Number: 96

- 004

- 1028: 1028.000.268: AMR 3679

- 95. Unpublished study prepared by Springborn Labs., (Europe) AG. 41 p.

44217702 Kuehner, C. (1995) DPX

- KV141

- 12: Acute Toxicity to the Predatory Mite,

Typhlodromus pyri Scheuten (Acari: Phytoseiidae) in the Lab oratory: Final Report: Lab Project Number: 3133

- 94: 94113/94114/01

- NLTP. Unpublished study prepared by GAB Biotechnologie GMBH and IFU Umweltanalytik GMBH. 28 p.

44217703 Kuhner, C. (1995) DPX

- KV141

- 12: Acute Toxicity to the Aphid Parasitoid,

Aphidius sp p. (Hymenoptera, Aphidiidae) in the Laboratory: Final Report: Lab Project Number: 3135

- 94: 94113/94114/01

- NLAP. Unpublished study prepared by GAB Biotechnologie GMBH and IFU Umweltanalytik GMBH. 36 p.

### 46



# APPENDIX 2. Uncertainties Related to the Use of Incident Information from the Ecological Incident Information System

Incident data are used in risk assessments to provide evidence that the risk predictions from the screening level assessment are supported by actual effects in the field. Incident repor ts submitted to EPA since approximately 1994 have been tracked by assignment of incident numbers in an Incident Data System (IDS), microfiched, and then entered to a second database, the Ecological Incident Information System (EIIS). Additionally, there i s an on

- going effort to enter information to EIIS on incident reports received prior to establishment of current databases. Incident reports are not received in a consistent format ( e.g ., states and various labs usually have their own formats), may involv e multiple incidents involving multiple chemicals in one report, and may report on only part of a given incident investigation ( e.g ., residues).

Incidents entered into EIIS are categorized into one of several certainty levels regarding the likelihood th at a particular pesticide is associated with the incident: highly probable, probable, possible, unlikely, or unrelated. In brief, “highly probable” incidents usually require carcass residues and/or clear circumstances regarding the exposure. “Probable” i ncidents include those where residues were not available and/or circumstances were less clear than for “highly probable.” “Possible” incidents include those where multiple chemicals may have been involved and it is not clear what the contribution was of a given chemical. The “unlikely” category is used, for example, where a given chemical is practically nontoxic to the category of organism killed and/or the chemical was tested for but not detected in samples. “Unrelated” incidents are those that have been confirmed to be not pesticide

- related.

Incidents entered into the EIIS are also categorized as to use/misuse. Unless specifically confirmed by a state or federal agency to be misuse, or there was very clear misuse such as intentional baiting to kill wil dlife, incidents are not typically considered misuse.

The number of documented kills in EIIS is believed to be a small fraction of total mortality caused by pesticides. Mortality incidents must be seen, reported, investigated, and have investigation re ports submitted to EPA to have the potential for entry into the database. Incidents often are not seen, due to scavenger removal of carcasses, decay in the field, or simply because carcasses may be hard to see on many sites and/or few people are systemati cally looking. Poisoned animals may also move off

- site to less conspicuous areas before dying. Incidents may not get reported to appropriate authorities capable of investigating the incident for a variety of reasons including the finder may not know of t he importance of reporting incidents, may not know who to call, may not feel they have the time or desire to call, or may hesitate to call because of their own involvement in the kill. Incidents reported may not get investigated if resources are limited o r may not get investigated thoroughly, with residue analyses, for example. Also, if kills are not reported and investigated promptly, there will be little chance of documenting the cause, since tissues and residues may deteriorate quickly. Reports of inv estigated incidents often do not get submitted to EPA, since reporting by states is voluntary.

Furthermore, the database relies heavily on registrant

- submitted incident reports, and registrants are currently only required to submit detailed information on ‘major’ ecological incidents, while ‘minor’ incidents are reported aggregately.

### 47

Based on the 40 CFR (§159.184 Toxic or adverse effect incident reports), an ecological incident is considered ‘major’ if any of the following criteria are met:

Fish or wil dlife :

(A) Involves any incident caused by a pesticide currently in Formal Review for ecological concerns.

(B) Fish: Affected 1,000 or more individuals of a schooling species or 50 or more individuals of a non

- schooling species.

(C) Birds: Affected 200 or more individuals of a flocking species, or 50 or more individuals of a songbird species, or 5 or more individuals of a predatory species.

(D) Mammals, reptiles, amphibians: Affected 50 or more individuals of a relatively

common or herding species or 5 or more individuals of a rare or solitary species.

(E) Involves effects to, or illegal pesticide treatment (misuse) of a substantial tract of habitat (greater than or equal to 10 acres, terrestrial or aquatic).

Plants :

(A) The effect is alleged to have occurred on more than 45 percent of the acreage exposed to the pesticide.

All other ecological incidents are considered ‘minor’ and only need to be aggregately reported. ‘Minor’ incidents reported by the registrants are not incl uded in the EIIS database. Therefore, for example, an incident could affect 900 fish, 150 birds, 45 mammals, and 40% of an exposed crop and not be included in the EIIS database [unless is it reported by a non

- registrant ( e.g ., an incident submitted by a s tate agency

– which are not systematically collected)]. Therefore, because the number of documented kills in EIIS is believed to be a small fraction of total mortality caused by pesticides, absence of reports does not necessarily provide evidence of an ab sence of incidents.

### 48



# APPENDIX 3. SIP v.1.0 Inputs and Outputs

SIP employs the following conservative assumptions to derive upper bound exposure estimates: 1) The chemical concentration in drinking water is at the solubility limit in water (at 25 o 

### C). 2) The assessed animals obtain 100% of their daily water needs through drinking water. 3) The daily water need is equivalent to the daily water flux rate as calculated by Nagy and Peterson (1988). 4) The body weight of the assessed bird is equivalent to the smallest generic bird modeled in T

- REX (i.e., 20 g). This assumption results in the highest ratio of exposure to toxicity for the 3 assessed avian body weights of T

- REX (i.e., 20, 100, 1000 g). 5) The body weight of the assessed mammal is equivalen t to the largest generic mammal modeled in T

- REX (i.e., 1000 g). This results in the highest ratio of exposure to toxicity for the 3 assessed mammalian body weights of T

- REX (i.e., 15, 35, 1000 g).

Table 1. Inputs Parameter Value Chemical name Rimsulfuron Solubility (in water at 25 o C; mg/L) 7300

Mammalian LD 50 (mg/kg

- bw) 5000 Mammalian test species laboratory rat Body weight (g) of "other" mammalian species

Mammalian NOAEL (mg/kg

- bw) 165 Mammalian test species laboratory rat Body weight (g) of "other" mammalian species

Avian LD 50 (mg/kg

- bw) 2000 Avian test species mallard duck Body weight (g) of "other" avian species Mineau scaling factor 1.15

Mallard NOAEC (mg/kg

- diet) 1250 Bobwhite quail NOAEC (mg/kg

- diet) NOAEC (mg/kg

- diet) for other bird species Body weight (g) of other avian species NOAEC (mg/kg

- diet) for 2nd other bird species Body weight (g) of 2nd other avian species

### 49

Table 2. Mammalian Results Parameter Acute Chronic Upper bound exposure (mg/kg

- bw) 1255.6000 1255.6000 Adjusted toxicity value (mg/kg

- bw) 3845.8028 126.9115 Ratio of exposure to toxicity 0.3265 9.8935

Conclusion* Exposure through drinking water alone is a potential concern for mammals Exposure through

drinking water alone is a potential concern for mammals

Table 3. Avian Results Parameter Acute Chronic Upper bound exposure (mg/kg

- bw) 5913.0000 5913.0000 Adjusted toxicity value (mg/kg

- bw) 1038.4508 62.0157 Ratio of exposure to acute toxicity 5.6941 95.3468

Conclusion* Exposure through drinking water alone is a potential concern for birds Exposure through

drinking water alone is a potential concern for

birds

*Conclusion is for drinking water exposure alone. This does not combine all routes of exposure. Therefore, when aggregated with other routes ( i.e ., diet, inhalation, dermal), pesticide exposure through drinking water may contribute to a total exposure that has potential for effects to non

- target animals.

### 50



# APPENDIX 4. STIR v.1.0 Inpu ts and Outputs

Rim sulfuron 

# Welcome to the EFED Screening Tool for Inhalation Risk This tool is designed to provide the risk assessor with a rapid method for determining the potential significance of the inhalation exposure route to birds and mammals in a risk assessment.



# Input

Application and Chemical Information
Enter Chemical Name Rimsulfuron Enter Chemical Use Herbicide Is the Application a Spray? (enter y or n) y If Spray What Type (enter ground or air) ground Enter Chemical Molecular Weight (g/mole) 431.44 Enter Chemical Vapor Pressure (mmHg) 1.10E

- 08 Enter Application Rate (lb a.i./acre) 0.0625

Toxicity Properties

Bird Enter Lowest Bird Oral LD 50 (mg/kg bw) 2000 Enter Mineau Scaling Factor 1.15 Enter Tested Bird Weight (kg) 1.58 Mammal
Enter Lowest Rat Oral LD 50 (mg/kg bw) 5000
Enter Lowest Rat Inhalation LC 50 (mg/L) 5 Duration of Rat Inhalation Study (hrs) 4 Enter Rat Weight (kg) 0.35


# Output Results Avian (0.020 kg ) Maximum Vapor Concentration in Air at Saturation (mg/m 3 ) 2.55E

- 04 Maximum 1

- hour Vapor Inhalation Dose (mg/kg) 3.21E

- 05 Adjusted Inhalation LD 50 8.04E+00

Ratio of Vapor Dose to Adjusted Inhalation LD 50 3.99E

- 06 Exposure not Likely Significant
Maximum Post

- treatment Spray Inhalation Dose (mg/kg) 6.60E

- 03 Ratio of Droplet Inhalation Dose to Adjusted Inhalation LD 50 8.22E

- 04 Exposure not Likely Significant

### 51

Results Mammalian (0.015 kg ) Maximum Vapor Concentration in Air at Saturation (mg/m 3 ) 2.55E

- 04 Maximum 1

- hour Vapor Inhalation Dose (mg/kg) 4.04E

- 05 Adjusted Inhalation LD 50 2.98E+02

Ratio of Vapor Dose to Adjusted Inhalation LD 50 1.36E

- 07 Exposure not Likely Significant Maximum Post

- treatment Spray Inhalation Dose (mg/kg) 8.30E

- 03 Ratio of Droplet Inhalation Dose to Adjusted Inhalation LD 50 2.79E

- 05 Exposure not Likely Significant

### 52



# APPENDIX 5 . The Risk Quotient Method and Levels of Concern

The Risk Quotient Method is the means used by EFED to integrate the results of exposure and ecotoxicity data. For this method, Risk Quotients (RQs) are calculated by dividing exposure estimates by the acute and chronic ecotoxicity values (i.e., RQ = EXPOSU RE/TOXICITY). These RQs are then compared to OPP's levels of concern (LOCs). These LOCs are criteria used by OPP to indicate potential risk to non

- target organisms and the need to consider regulatory action. EFED has defined LOCs for acute risk, potential restricted use classification, and for endangered species.

The criteria indicate that a pesticide used as directed has the potential to cause adverse effects

on non

- target organisms. LOCs currently address the following risk presumption categories:

(1) acute

- there is a potential for acute risk; regulatory action may be warranted in addition to restricted use classification;

(2) acute restricted use

- the potential for acute risk is high, but this may be mitigated through restricted use classifica tion;

(3) acute endangered species

- the potential for acute risk to endangered species is high, regulatory action may be warranted; and

(4) chronic risk

- the potential for chronic risk is high, regulatory action may be warranted.

Currently, EFED do es not perform assessments for chronic risk to plants, acute or chronic risks to non

- target insects, or chronic risk from granular/bait formulations to mammalian or avian species.

The ecotoxicity test values (i.e., measurement endpoints) used in the acute and chronic RQs are derived from required studies. Examples of ecotoxicity values derived from short

- term laboratory studies that assess acute effects are: (1) LC50 (fish and birds), (2) LD50 (birds and mammals), (3) EC50 (aquatic plants and aquatic inver tebrates), and (4) EC25 (terrestrial plants). Examples of toxicity test effect levels derived from the results of long

- term laboratory studies that assess chronic effects are: (1) the Lowest Observed Adverse Effect Concentration (LOAEC) (birds, fish, and a quatic invertebrates), and (2) the No Observed Adverse Effect Concentration (NOAEC) (birds, fish and aquatic invertebrates). The NOAEC is generally used as the ecotoxicity test value in assessing chronic effects. Risk presumptions, along with the
correspon ding RQs and LOCs are summarized in Table B1

.

### 53

Table B1. Agency risk quotient (RQ) metrics and levels of concern (LOC) per risk class.

Risk Class Risk Description RQ LOC

Aquatic Animals (fish and invertebrates)

Acute Potential for effects to non

- listed animals from acute

exposures Peak EEC/LC 50 1 0.5

Acute Restricted Use Potential for effects to animals from acute exposures

Risks may be mitigated through restricted use classification Peak EEC/LC 50 1 0.1

Acute Listed Species Listed species may be potentially affected by acute

exposures Peak EEC/LC 50 1 0.05

Chronic Potential for effects to non

- listed and listed animals

from chronic exposures 60

- day EEC/NOEC (fish) 1

21

- day EEC/NOEC (invertebrates)

Terrestrial Animals (mammals and birds)

Acute Potential for effects to non

- listed animals from acute

exposures EEC 2 /LC 50 (Dietary) 0.5

EEC/LD 50 (Dose)

Acute Restricted Use Potential for effects to animals from acute exposures

Risks may be mitigated through restricted use classification EEC 2 /LC 50 (Dietary) 0.2

EEC/LD 50 (Dose)

Acute Listed Species Listed species may be potentially affected by acute

exposures EEC 2 /LC 50 (Dietary) 0.1

EEC/LD 50 (Dose)

Chronic Potential for effects to non

- listed and listed animals

from chronic exposures EEC 2 /NOAEC 1

Plants

Non

- Listed Potential for effects to non

- target, non

- listed plants

from exposures EEC/ EC 25 1

Listed Plant Potential for effects to non

- target, listed plants from

exposures EEC/ NOEC 1

EEC/ EC 05

1 LC 50 or EC 50 . 2 Based on upper bound Kenaga values.