### Page 2 of 63

The Registration Review considers existing uses; ho wever, aminopyralid is proposed for use via direct application to water for aquatic plant control, and this use is evaluated as well in this problem form ulation. Aminopyralid acid and its associated salts are plan t growth regulators. Aminopyralid in both salt and acid forms will readily dissociate in water at ambient p H to yield the aminopyralid anion. Because of similarities in metabolism and effects in animals, plants, and the environment, aminopyralid in its ac id and salt forms were considered equivalent in previous r isk assessments, and for the purposes of this probl em formulation are considered equivalent as well. The term “aminopyralid” is thus used in this document to refer to compounds containing the aminopyralid anio n generically, unless a specific form is noted.

This problem formulation describes the methods plan ned to be used during the completion of drinking water and ecological risk assessments in support of Registration Review, and provides an overview of t he environmental fate, ecological effects, and potenti al risks associated with the use of aminopyralid as well as uncertainties unique to the risk assessment of a minopyralid. This document also identifies additio nal studies that would address uncertainties in assessi ng ecological risk associated with current uses of aminopyralid. Uncertainties include:

• The fate database is incomplete based on the enviro nmental fate data requirements outlined in the Code of Federal Regulations Title 40 Part 158 (40CF R158) Subpart N 1 

### and data are needed to complete and reduce uncertainty in risk assessments . Additional data on the following fate parameters are recommended.

o Aerobic aquatic metabolism data (OCSPP 2 

### Guideline 835.4300 ). Aerobic conditions were not maintained throughout the aerobic aquatic studies. In the absence of an acceptable study, the model half-life input for aerobic aquatic metabolism will be assumed to be twice the aerobic soil metabolism half-life, per EFED’s input parameter gu idance (USEPA, 2009b). Additional data are recommended in part because of potential risk to te rrestrial plants via exposure from irrigation water. Additionally, this study is recommended bec ause a proposed use involves direct application to water. This study will reduce uncertainty regar ding potential exposure to aquatic organisms and terrestrial plants. Aminopyralid in any of its thr ee chemical forms (salt or acid) listed above may b e used as the test item.

o Dissipation study in compost (Non-Guideline): Aminopyralid applied to vegetative matter used as animal feed, from which manure is produced that is subsequently composted, has been found to remain present in sufficient quantity to damage non -target plants (see Section 6c Ecological Incidents). A study is requested to quantify rates of aminopyralid degradation within composted material. The study will be used to characterize p otential risk from aminopyralid residues in compost, and to help identify potential mitigation measures for existing uses. A protocol for this non-guideline study should be submitted to the EPA for review and approval prior to initiation of the study. Aminopyralid in any of its three chemic al forms (salt or acid) listed above may be used as the test item.

o Environmental Chemistry Methods and Independent Lab oratory Validation on Compost (OCSPP Guideline 850.6100): Data are requested for environmental chemistry me thods (ECM) on compost and independent laboratory validation (I LV) of the method. For compost, methods should be derived that can be used with equipment f ound in state laboratories and use analytical standards that can be readily obtained. Methods sh ould be able to detect parent and any degradates that are identified as residues of concern. Curren tly, the residues of concern identified include aminopyralid and unextracted residues.

o Data to better understand risk from residues in gro undwater used as irrigation water (OCSPP 835.7100): Residues of aminopyralid have been detected in gr oundwater and other

1 CFR. 2013. Title 40 (Protection of the Environment ), Chapter 1 (Environmental Protection Agency), Sub chapter E (Pesticide Programs), Part 158 (Data Requirements for Pesticid es), Subpart N (Environmental Fate) http://www.ecfr.gov/cgi-bin/textidx?c=ecfr&SID=ff5c7fef3645e7cd5abceca0b597bccb&tpl =/ecfrbrowse/Title40/40cfr158_main_02.tpl 2 The Series 835 Fate Guidelines were completed when the Office of Chemical Safety and Pollution Prevent ion (OCSPP) was known as the Office of Prevention, Pesticides, and Toxic Substances (OPPTS).

### Page 3 of 63

picolinic acids have incidents where residues of pi colinic acids in groundwater resulted in damage to terrestrial plants. Additionally, risk assessme nts for aminopyralid have identified this pathway a s a potential concern for damage to terrestrial plant s. Additional data are recommended to better understand the potential for risk due to residues o f aminopyralid in groundwater. Studies that would be useful include a prospective groundwater m onitoring study or studies to refine groundwater modeling inputs for the Pesticide Root Zone Model for Groundwater (PRZM-GW) model. A prospective groundwater monitoring study could be used to determine where groundwater concerns were likely to occur and wheth er what we predict based on laboratory data, is observed in the field. Additionally, it could b e used to determine vulnerability of different area s. Data to refine inputs to PRZM-GW may be used to ref ine modeling estimates of groundwater concentrations. Studies may involve understanding sorption or degradation in subsurface environments. It is recommended that a protocol be submitted, prior to conducting any of these studies. In the absence of more suitable inputs or scenarios, estimated environmental concentrations (EECs) generated from PRZM-GW in the same fashion as estimated drinking water concentrations (EDWCs) for groundwater used as drin king water, will be used to characterize risks to terrestrial plants from residues in irrigation w ater obtained from groundwater sources.

• The ecological database is also incomplete based on the ecological effects data requirements outlined in the 40CFR158 Subpart G 3



### .

o Data are needed for the following studies on a repr esentative Typical End-Use Product (TEP) that contains i ) aminopyralid and 2,4-D; ii ) aminopyralid and triclopyr; iii ) aminopyralid and clopyralid; iv ) aminopyralid and metsulfuron; and v ) aminopyralid and fluroxypyr-1- methylheptyl ester.

o Freshwater invertebrate acute toxicity (OCSPP 850.1 010)

o Tier II Terrestrial plant vegetative vigor (OCSPP 850.4100) and seedling emergence (OCSPP 850.4250) including soybean, lettuce, and on ion

o Aquatic plant growth (freshwater diatom, Navicula pelliculosa) (Tier II) (OCSPP 850.4500)

Additionally, an aquatic plant growth study for cya nobacteria (OCSPP 850.4550) is needed using a representative product that contains aminopyralid only.

Finally, EFED is requesting a non-standard study (O ECD 237) to assess aminopyralid TGAI toxicity to developing bee larva.

• Section 3 of this document discusses information on labels that are needed to reduce uncertainty in ri sk assessments. These uncertainties include labels th at do not have maximum single application rates, maximum annual application rates, and/or minimum re treatment intervals. Many of these uncertainties apply to uses on trees and in foreste d areas. Additionally, some labels include very br oad use sites such as “non-crop areas” and various area s that could be considered aquatic use sites, i.e

., direct applications to water.

2. Introduction

Aminopyralid is a systemic synthetic auxin analogue in the pyridine carboxylic acid (also known as picolinic acids) class of herbicides and functions as a plant growth regulator (Ware and Whitacre, 200 4;

3 CFR. 2013. Title 40 (Protection of the Environment ), Chapter 1 (Environmental Protection Agency), Sub chapter E (Pesticide Programs), Part 158 (Data Requirements for Pesticid es), Subpart G (Ecological Effects) http://www.ecfr.gov/cgi-bin/textidx?c=ecfr&SID=ff5c7fef3645e7cd5abceca0b597bccb&rgn =div6&view=text&node=40:25.0.1.1.9.7&idno=40

### Page 4 of 63

Wood, 2013). The compound has been registered in t he United States for use in controlling annual and perennial broadleaf weeds since 2005.

EFED evaluated the most recent ecological risk asse ssments for aminopyralid in association with any available updated toxicity, exposure, and usage inf ormation to determine if sufficient data are availa ble or if further updates are needed to support Registrati on Review. Recent risk assessments include the 201 0 EFED risk assessment of aminopyralid which reviewed the use of aminopyralid in forests, non-cropland, grazed areas, and industrial non-crop areas in Arka nsas (USEPA, 2010a, D383620). No new uses have been assessed since that time. Additionally, a dat a screen for proposed new uses directly to water wa s conducted (USEPA, 2013, D410811). EFED has also co nsidered the latest Agency science policies and risk assessment methodologies in compiling this pro blem formulation.

3. Use Characterization

Aminopyralid is formulated as an emulsifiable, flow able, soluble concentrate, and as water dispersible granules in multiple end-use products. Aminopyrali d is registered for use on a variety of agricultura l, forest, commercial, and residential areas and may b e applied via aircraft, ground sprayer, hand-held sprayer, and boom sprayer. Aminopyralid may also b e applied to forest plantings via broadcast, high volume spray, spot treatment, stump treatment, gird le treatment, frill treatment, tree wound treatment , and tree injection. Currently, there are 15 active Sec tion 3 registrations for aminopyralid including its salt forms and 36 Special Local Needs (SLN; Section 24c) registrations ( Table 1 ). Twelve products containing aminopyralid include multiple active ing redients. Aminopyralid TIPA salt occurs in combination with:

• TIPA salt of 2,4-D (PC code 030035; 2,4-dichlorophe noxyacetic acid, triisopropanolamine salt),

• 2,4-D dimethylamine salt (PC code 030019; 2,4-dichl orophenoxyacetic acid dimethylamine salt), and

• triclopyr triethylamine salt (PC Code 116002; N,N-d iethylethanamine;2-(3,5,6-trichloropyridin-2- yl)oxyacetic acid)). Some aminopyralid potassium salt products also cont ain the active ingredients metsulfuron (PC code 122010; 2-[(4-methoxy-6-methyl-1,3,5-triazin-2-yl)c arbamoylsulfamoyl]benzoic acid)) and clopyralid (PC code 117403; 3,6-dichloro-2-pyridinecarboxylic acid ). One product containing aminopyralid is combined with fluroxypyr 1-methylheptyl ester (PC code 12896 8; 1-methylheptyl (4-amino-3,5-dichloro-6-fluoro-2- pyridyloxy)acetate). Details on the percent active ingredients in currently registered products are p rovided in Appendix A . Clopyralid, 2,4-D, triclopyr, and fluroxypyr-1-m ethylheptyl ester have the same mode of action as aminopyralid ( i.e. , mimicking natural auxins and serving as plant gro wth regulators) (HRAC, 2005). Metsulfuron is a sulfonylurea and inhibits branched chain amino acid biosynthesis through the inhibition of the enzyme acetaolactate synthetase, i.e ., ALS inhibitor (Ware and Whitacre, 2004).

Table 1. Number of national (Section 3) and Specia l Local Needs (SLN; Section 24c) registrations for aminopyralid acid and its salts.

Active Ingredient Number of

National Registrations Number of SLN -

Registrations (states with registrations) Number of products with Multiple active ingredients, other active

ingredients

Aminopyralid TIPA salt 9 32 (AL, CA, FL, GA, HI, LA, MN, MS, NC, SC, TX, VA) 8 products, 2,4-D TIPA salt, 2,4-D dimethylamine salt Triclopyr Trielthylamine salt
Aminopyralid Potassium salt 4 3 (ID, OR, WA) 3 products, Metsulfuron, Clopyralid Aminopyralid acid 2 1 (FL) 1 product, Fluroxypyr 1-methylheptyl ester

### Page 5 of 63

Aminopyralid (acid and salts) is registered for use on corn, wheat, grasses, pastures, rangeland, ditc h banks, swamps, flood plain, marshes, conservation r eserve program land, non-crop areas, campgrounds, recreational areas, roadsides, rights-of-ways, trai ls, industrial sites, nonagricultural areas, forest lands, aquatic areas, recreational areas, forest plantatio ns, conifers, and deciduous trees. The maximum sin gle and annual application rate reported is 0.86 lbs po tassium salt /A or 0.73 lbs acid equivalents (a.e.) /A.

In 2013, a proposal for a Section 3 new use of usin g aminopyralid for control of broadleaf and woody plants and annual grasses (knotweeds (Japanese, Boh emian, and others), purple loosestrife, tropical so da apple, Japanese stiltgrass, Canada thistle, and Pen nsylvania smartweed) in aquatic sites was submitted

. The proposed labels define aquatic sites as “ non-irrigation ditch banks, seasonally dry wetlands such as flood plains, deltas, marshes, swamps, or bogs, tra nsitional areas between upland and lowland sites as well as along shorelines and shallow areas of still and moving water sites .” The submission is currently under review.

The Screening Level Usage Analysis (SLUA) conducted by the Biological and Economic Analysis Division (BEAD) estimates the following agricultura l uses during 2004-2011 (USEPA, 2013b):

• pasture 90,000 lbs acid equivalent (a.e.),

• wheat 1,000 lbs a.e.

• fallow land <500 a.e..

• corn <500 a.e. The percent crop treated estimates were all less th an 2.5%. The SLUA analysis is only applicable to agricultural uses; therefore, non-agricultural usag e (including residential, forest, and industrial applications) of aminopyralid is not captured in th e SLUA.

The chemical profile produced by BEAD, located in t he docket, lists the use patterns associated with a ctive registrations of aminopyralid. EFED will rely on t he BEAD chemical profile when estimating environmental exposures that result from these regi stered uses. Additionally, in order to be protecti ve, EFED will utilize the use information that results in maximum exposure ( e.g. , concentration) estimates for a given use pattern for the drinking water and ecol ogical risk assessments. If the labels (and conseq uently the BEAD chemical profile) do not include all infor mation needed to enable estimation of maximal exposures, such as the maximum single application r ate, minimum application interval, annual maximum rate allowed (lbs a.i. or a.e./year), and applicati on method, EFED will make conservative assumptions regarding these use parameters.

Some use patterns are not sufficiently characterize d to permit ready calculation of a maximum applicat ion rate per acre, or else involve very broad use sites . More information on the following items would re duce uncertainty regarding such uses in the risk assessm ent:

• Some labels have instructions for applications to t rees (cut surface, cut-stump treatment, tree inject ion, hack and squirt treatment, and frill and girdle met hod). The label should specify the maximum amount of aminopyralid that may be applied per tree ( e.g ., as a function of trunk diameter), as well as the maximum number of trees that may be treated per acr e. This is because maximum application rates (both single and total annual) in lbs a.i or a.e./A are needed in order to model exposures resulting f rom these types of uses. Additionally, the maximum num ber of applications per year and minimum retreatment interval should be specified for these uses.

• The labels have several nonspecific use sites. The se broadly-categorized use sites will require EFED to employ the assumption that aminopyralid can be u sed at a broad range of agricultural, commercial, residential, and forest sites. These use sites wil l also necessitate the assumption that application may occur to both aquatic and terrestrial environments. The following are examples of nonspecific use sites:

### Page 6 of 63

o non-irrigation ditch banks, seasonally dry wetlands (such as flood plains, deltas, marshes, swamps, or bogs), transitional areas between upland and lowland sites when dry, ditchbank weeds, shoreline weeds, non-cropland areas, and nat ural areas. The Agency encourages that use site descriptions be made as specific as possible, so that potential us e areas are not broader than necessary. Vague use si te descriptions can impact assumptions made when doing proximity analysis for determinations on the potential risks to federally listed threatened/endangered (hereafter referred to as “li sted”) species.

• Some restrictions are specified on a product basis rather than on an active ingredient basis.

• Some labels only include a maximum single applicati on rate. They do not include a maximum annual or seasonal application rate, maximum number of app lications, or minimum retreatment interval (see the EFED label Data Report for 005209).

• Some labels with multiple active ingredients, where acid equivalents are relevant, provide acid equivalent restrictions but do not specify to which active ingredient the limitations apply.

4. Conclusions from Previous Risk Assessments

a. Ecological Risk Assessment

Four previous risk assessments have been completed for aminopyralid (including salt and acid forms): a reduced risk assessment in 2004 (USEPA, 2004, D3066 47); a new use assessment in 2005 (USEPA, 2005, D301682) and a new use assessment in 2009 (USEPA, 2 009, D361924); and a Section 24C Special Local Needs Assessment in 2010 (USEPA, 2010a, D383620). The uses evaluated in the risk assessments include: field corn, corn grown for ensilage, wheat , pasture/rangeland, industrial vegetation, roadsid es, rights-of-way, conifer forest site preparation, con ifer release, mid-rotation understory brush and wee d control in loblolly, slash, shortleaf, and longleaf pine stands, and control of herbaceous and woody p lants in forests, non-cropland, grazed areas, and industr ial non-crop areas. All of the risk assessments fo und potential for direct risk to listed and non-listed terrestrial plants. Due to potential direct advers e effects on terrestrial plants, indirect effects to all listed aquatic and terrestrial plants and animals could oc cur. In addition to direct risk to terrestrial plants due t o transport via spray drift and runoff to adjacent areas, previous assessments have highlighted exposure path ways of residues in irrigation water (including groundwater) and compost (manure and plant material ). Incident data have reported adverse effects to terrestrial plants exposed to aminopyralid in resid ues in hay and manure used in composting. Also, du e to aminopyralid’s persistence and mobility, it may lea ch to groundwater and/or move into surface water through runoff.

Because aminopyralid in both salt and acid forms di ssociates readily in water to release the aminopyra lid anion, and ecotoxicity data were similar for aminop yralid salts and aminopyralid acid, EFED bridged th e ecotoxicity data studies for aminopyralid salts wit h aminopyralid acid. In other words, exposure was estimated for aminopyralid acid, and toxicity data were expressed in terms of acid equivalents for the risk
assessment.

The major environmental fate and ecological risk co nclusions identified in previous assessments are summarized in Table 2 and 3

.

Table 2. Potential for direct effects identified i n previous assessments for aminopyralid 1
Listed/or non-listed Birds 2 Mammals Terrestrial Invertebrates Aquatic

Vertebrates 3 Aquatic

Invertebrates Terrestrial

Plants Aquatic

Plants Non-listed --*

-- -- -- -- Yes

-- Listed --

-- -- -- -- Yes

-- -- = Risk below LOC; * indicates a full data set is not available

1 Risk concerns were identified when the RQ exceeded the corresponding level of concern in a previous ri sk assessment or were identified as a potential concern based on weight of evidence.

2 Birds serve as surrogates for terrestrial-phase amp hibians and reptiles.

### Page 7 of 63 3 Fish serve as surrogates for aquatic-phase amphibia ns.

Table 3. Potential environmental fate concerns ide ntified in previous assessments for aminopyralid Bioconcentration/ Bioaccumulation 1 Groundwater

Contamination 2 Sediment Persistence Residues of Concern Volatilization

No, log K ow <3 Yes 2 No Yes Aminopyralid acid and Unextracted Residues No

1 Based on whether previous assessments indicated thi s was a risk concern or if previous assessments ran K ow Based Aquatic Bioaccumulation Model (KABAM) for chemicals with a log K ow >3.
2 Previous risk assessments indicated that aminopyral id has the potential to reach groundwater; however, it did not result in drinking water concentrations high enough to cause a concern for h uman health. However, residues could be high enoug h to present a risk to terrestrial plants exposed to irrigation water. Aminopyralid residues may also be transported to surface water via spray drift, run-off, and erosion. Screening level Estimated Drinking Water Concentrations (EDWC) in s urface water have not been high enough to cause con cern for human health; however, they have been high enough to result in a concern for th e potential effects to terrestrial plants via expos ure to aminopyralid residues in irrigation water.



### b. Drinking Water Exposure Assessments

The most recent drinking water assessment was compl eted in 2010 (USEPA, 2010b, D383620) and the estimated drinking water concentrations (EDWCs) for human health risk assessment are shown in Table 4

. The Health Effects Division (HED) determined that t he residue of concern for aminopyralid in terms of human health was aminopyralid anion (USEPA, 2005b, D301689). Unextracted residues were also considered a residue of concern in the drinking wat er assessments because a range of polar and nonpola r solvents were not explored to determine if the amou nt of unextracted residues could be decreased and t he identity of the unextracted residues is unknown. I n 2010, surface- and groundwater-based EDWCs for aminopyralid were well below the level of concern ( LOC) for human health). Because EFED has recently implemented revised percentage crop area (PCA) fact ors, and introduced the Pesticide Root Zone ModelGroundWater (PRZM-GW) model to determine EDWCs in g roundwater, an updated drinking water assessment will be completed. The HED will likely conduct a new dietary exposure and risk assessment if there are significant changes from previously-calcu lated EDWCs.

Table 4. Tier I EDWCs for drinking water risk asse ssment based on aminopyralid use at 0.11 lbs a.e./acre/year for forest uses.

Source of Drinking Water Aminopyralid acid (including unextracted residues) concentration in drinking water (μg/L) Acute Annual Average Surface water 11.4 μg/L 2.19 μg/L
Groundwater 6.43



### c. Clean Water Act Programs

Aminopyralid is not identified as a cause of impair ment for any water bodies listed as impaired under section 303(d) of the Clean Water Act. 4 

### No Total Maximum Daily Loads (TMDL) or section 30 4(a) ambient water quality criteria have been developed for aminopyralid. 5 

### Aquatic life benchmarks 6 

### have been established for aminopyralid; however, any dat a submitted or otherwise located as part of the Registration Review process that indicate greater s ensitivity than data currently available may be use d to revise aquatic life benchmarks if applicable.

4 Specific state causes of impairment that make up t he national pesticides cause of impairment group ar e listed at http://iaspub.epa.gov/tmdl_waters10/attains_nation_ cy.cause_detail_303d?p_cause_group_id=885

. 5 Specific state pollutants that make up the Nationa l Pesticides Pollutant Group and have TMDLs are lis ted at http://iaspub.epa.gov/tmdl_waters10/attains_nation. tmdl_pollutant_detail?p_pollutant_group_id=885&p_po llutant_gr oup_name=PESTICIDES

. 6 Aquatic Life Benchmarks are available at ( http://www.epa.gov/oppefed1/ecorisk_ders/aquatic_li fe_benchmark.htm.

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5. Environmental Fate and Transport

Under most environmentally relevant conditions, ami nopyralid will exist in an ionic form. The acid lo g dissociation constant (pKa of 2.56) indicates that greater than 97% of the compound will be in the ani onic (negatively charged) form at environmentally-releva nt pH ranges (pH 4.0-9.0), regardless of the origin al molecular species. This shows that in water the ch emical of relevance in terms of organism exposure i s the aminopyralid anion. All environmental fate stu dies were conducted on aminopyralid acid (PC Code 005100) unless otherwise specified; aquatic exposur e was estimated in terms of acid equivalents in previous assessments.

Aminopyralid is relatively soluble (203 – 212 g/L a t 20 o 

### C) and is classified as mobile to highly mobile based on measured K oc 

### values (USEPA, 2010). It has the potential to rea ch groundwater, especially in vulnerable soils with low organic-carbon content an d/or the presence of shallow groundwater. This is supported by the leaching observed in some terrestr ial field dissipation studies in which aminopyralid was measured at up to 90 cm depth in the soil, which wa s the lowest depth sampled. This ensued when a rai n event occurred close to the time of application. A minopyralid may also be transported to surface wate r via runoff and spray drift. While it may be found in b oth water and sediment, the octanol-water partition coefficient (K OW 

### ) and organic-carbon normalized soil-water distribu tion coefficient (K OC 

### ) values are much lower than the values that would trigger the need t o request sediment toxicity studies (40 CFR Part 158.630). 7 

### Compounds with a log K OW 

### of three and above are generally considered to hav e the potential to bioconcentrate in aquatic organisms. Based on log K OW 

### ’s ranging from -2.96 to -1.76, aminopyralid is not likely to bioconcentrate in organisms. Aminopyrali d is classified as non-volatile from water, dry non

adsorbing surfaces, and moist soil (USEPA, 2010). The estimated octanol-air partition coefficient (K OA 

### ) value is 3.88 × 10 -15 

### , and aminopyralid is not likely to accumulate in t errestrial organisms. 8



### Fate study results indicate that aminopyralid may r ange from non-persistent to very persistent in the environment. 9 

### Aminopyralid is stable to hydrolysis at pH 5, 7, and 9 and essentially stable to anaerobic aquatic metabolism. Aminopyralid is degraded by ae robic metabolism in soils (half-lives ranged from 1 5 to 148 days at 20 o 

### C in eight soils). Unextracted residues made up a maximum of 24% of applied radioactivity in the aerobic soil metabolism studie s, and it is unknown what percentages of those resi dues were comprised of parent aminopyralid. Therefore, half-lives were also estimated assuming that the unextracted residues were aminopyralid, as done in previous aminopyralid ecological and drinking water assessments. Aerobic soil metabolism half-lives fo r aminopyralid plus unextracted residues ranged fro m 31 to 193 days at 20°C in the same eight soils. Th e aerobic aquatic metabolism half-lives are uncerta in because aerobic environments were not maintained th roughout the study. As anaerobic metabolism is expected to be slower than aerobic metabolism, the half-lives from the available aerobic aquatic study are expected to be conservative. Aminopyralid is likel y to be degraded via aqueous photolysis in clear wa ter and on moist leaf surfaces (aqueous photolysis half -life = 0.6 days).

Dissipation half-lives in reviewed terrestrial fiel d dissipation studies ranged from 24 to 36 days at two sites in the United States. Dissipation half-lives repor ted in as-yet unreviewed terrestrial field dissipat ion studies ranged from 9 to 54 days at six sites in th e United States and Canada. Time to 90% dissipatio n (DT 90 

### ) ranged from 40 to 430 days. Carryover of residues was minimal at six sites (carryover ranged from

7 Sediment data may be required if the soil-water di stribution coefficient (K d ) is ≥ 50 L/kg, K OC s are ≥ 1000 L/kgorganic carbon, and the log K OW is ≥ 3 (40 CFR Part 158.630). Sediment data may also b e requested if there may be a toxicity concern.
8 A recent FIFRA Scientific Advisory Panel (SAP) rep orted, “Gobas et al (2003) concluded that chemicals with a log K OA greater than five can biomagnify in terrestrial fo od chains if log K OW greater than two and the rate of chemical transformation is low. However, further proof is n eeded before accepting these limits without reserva tions” (USEPA, 2009c). This was also supported by the work of Arm itage and Gobas 2007.
9 Chemicals with half-lives greater than 60-days in soil, water, and sediment are classified as persist ent and chemicals with half-lives greater than 180 days are classifie d as very persistent (USEPA, 2012a).

### Page 9 of 63

0 to 2.7% at these sites after 121 to 372 days); ho wever, carryover was higher (5.7% after 121 days an d 6.2% after 455 days) at two sites. Aminopyralid’s half-lives based on aminopyralid residues alone sug gest that aminopyralid will not accumulate with successi ve applications; however, those that include unextracted residues indicate it may accumulate in some soils with successive applications. Overall, t hese results indicate that in some environments, aminopy ralid does persist while in others it is less persi stent. Additionally, incidents demonstrate that aminopyral id residues may be present at phytotoxic levels in composted manure. While most residues in terrestri al field dissipation studies remained in the top so il layer, residues were detected in the lowest depth ( 90 cm) sampled in one study when it rained within a few days of the application. This supports the analysi s that aminopyralid has the potential to leach to groundwater in some environments.

Two aquatic field dissipation studies have been com pleted. In one study, aminopyralid was broadcast along shorelines of a class 2 stream in Oregon (Str ahler stream order classification system) and a man

made canal in Florida for 225-foot and 15-ft swath widths (12-ft of shoreline and 3-ft into waterbody) (MRID 48939201) at an application rate of 0.11 lbs a.e./A. Aminopyralid concentrations were monitored within the treated area, and at upstream and downst ream locations. Maximum concentrations of aminopyralid observed in this study were 33 μg/L-wa ter, 15 μg/kg-sediment in a sample collected 8 days after application, and 333 μg/kg-soil in a sample c ollected 1-hour after application. Detections in s ediment were sporadic with most detections below 1 μg/kg-se diment. Dissipation half-lives were not calculated for data from the flowing water bodies. Residues in wa ter were transported rapidly from the treated area.

In the other aquatic field dissipation study, amino pyralid was broadcast at 0.036 lbs a.e./A 10 

### to the perimeter of two ponds (0.4 to 0.7 acre) in Texas a nd two ponds in Indiana (MRID 48939202). The targe t water concentration was 40 μg a.e./L. Caged catfis h ( Ictalurus sp.), sunfish ( Lepomis macrochirus ), clam ( Unionoida , species not reported), and crayfish ( Cambaridae sp.) were exposed and residues were measured. Some species were not fully identified i n the study. Maximum aminopyralid concentrations observed in water and tissue are reported in Table 5 . The maximum aminopyralid concentration observed in sediment was 4.4 μg/kg-sediment. Aquatic dissip ation half-lives ranged from 10.8 to 14.6 days. Vi sible light penetration was reportedly 30 to 31 inches. The sites were characterized as eutrophic and havin g a high level of biological productivity. Most UV-b l ight (86% was extinguished below this depth) was available in the top 2 inches of the water column. The majority of photolytic activity occurred in th e top 12 inches of the water column. The short half-live s observed may be related to the rapid aqueous photolysis rate of aminopyralid and would not likel y occur in areas where light penetration is minimal

. A selection of environmental fate and transport pro perties of aminopyralid is summarized in Table 5

.
Table 5. Chemical Properties and Environmental Fat e Parameters of Aminopyralid Acid (unless Otherwise Specified)
Parameter Value Description/Comments 1,2 Source Selected Physical/Chemical Parameters PC Code 005209 (TIPA Salt)

005100 (acid) 005219 (potassium salt) -- --

Molecular Mass 207.02 g/mol (acid)

398.27 g/mol (TIPA salt) 245.12 g/mol (potassium salt) -- --

Molecular Formula C 6 H 4 Cl 2 N 2 O 2 (acid) -- -- Vapor pressure o C Torr Pa Not expected to volatilize from dry MRID 4623570 1

10 This is a lower rate than that proposed for aquati c sites of 0.22 lbs a.i./A for spot treatments and 0.11 lbs a.i./A for broadcast and ground treatments



### .

### Page 10 of 63

Parameter Value Description/Comments 1,2 Source

20 7.14×10 - 11 9.52 × 10 - 9 surfaces. 2 Will vary with pH.

25 1.94 × 10 - 10 2.59 × 10 - 8

Aqueous solubility (20 o C) pH mg/L

Soluble, will vary with pH. MRID 46235701 5 212,000
7 205,000
9 203,000

Henry’s Law Constant (20°C; pH 7) 9.5 x 10 -17 atm-m 3 /mol Not expected to volatilize from water or moist/wet soil surfaces. 2 Will vary with pH. Estimated from vapor
pressure and water solubility at pH 7 and 20 o C. 1

Dissociation Constant pKa (20 o C) 2.56 at 20 o C Compound is a strong acid and will exist mainly in the dissociated form at most environmental pH values. As an anion, it will behave differently at various pH levels. MRID 46235701

Log octanol-to-water partition coefficient (Log K OW ) (19 o C) pH Log K OW

Will vary with pH. MRID 46235701 5 -1.76

7 -2.87

9 -2.96

Persistence 3

Hydrolysis half-life Stable (pH 5, 7, 9; 20 o C and

50 o C) Does not hydrolyze. MRID 46235726

Atmospheric Half-life 6.4 days (estimated) EPIWeb4.1, Appendix C

Aqueous photolysis half-life (20 ° C) 0.6 days (pH 5) 4 May photolyze in clear, shallow
waters. Adjusted for sunlight intensity at 40 ° N latitude. MRID 46235727

Soil photolysis halflife (25 ° C) 72.2 days (pH 7.7) 5 Adjusted for sunlight intensity at 40 ° N latitude. MRID 46235728

Aerobic soil metabolism half-life (10-30°C) pH, o C Acid Acid plus unextracted residues

Not persistent to very persistent 3 in

eight soils. One soil was tested at multiple temperatures. MRID 46235729 8 Holdrege 8 4.6, 25 42.0 58.2

Thessaloniki 7.7, 20 26.4 46.5

MRID 47911201 9 Cuckney 5.6, 20 147.5 192.5

Charentilly 5.8, 20 28.9 41.3

Parabraun 7.7, 20 86.6 126

Parabraun 7.7, 10 408 --

Parabraun 7.7, 30 107 --

### Page 11 of 63

Parameter Value Description/Comments 1,2 Source Calloway 6.6, 20 133.3 192.5

MRID 47925801 Fillmore 5.0, 20 92.4 141.5

Albany 4.6, 20 14.7 31.1

Anaerobic soil metabolism half-life No Data -- --
Aerobic aquatic metabolism half-life (20 ° C) pH Half-life (days) Not a rapid degradation pathway (very persistent 3 ). Aerobic environment was not maintained throughout the entire study. MRID 46235731 5.9 866

7.9 990

8.2 462 Anaerobic aquatic metabolism half-life (20-26 ° C) Stable (2 systems) Not a rapid degradation pathway (very persistent 3 ). MRID 46235730

Mobility 7

Solid-water distribution coefficient (K d ) in L/kg-soil (25 o C)

Organic-carbon normalized distribution coefficient (K OC ) in L/kg-oc

Freundlich solid-water distribution coefficient (K F ) and Freundlich Exponent (1/n) pH K d K oc K F 1/n Compound will exist primarily in dissociated form (as an anion) at most environmental pHs, and mobility may vary greatly with pH and other soil properties.

The relative standard deviation for K d values (132%) was higher than the relative standard deviation for K oc values (95%). While outliers were present, in general, K OC values decreased with increasing pH. There was not a consistent trend with K d values and pH. MRID 46235732 7.5 0.03 1.05 0.01 0.32

7.8 0.04 4.49 0.04 0.79

6.9 0.04 2.33 0.04 1.31

6.6 0.07 4.59 0.05 0.75

6.1 0.08 7.54 0.07 0.82

4.5 0.15 24.3 0.13 0.86

7.8 0.29 7.39 0.26 0.87

4.8 0.72 19.95 0.73 0.90

Field Dissipation

Terrestrial field dissipation half-life; leaching depth State/

Province Half-life

(days) Max

leaching depth (cm) Bare ground studies. Carryover from

year to year was not expected. MRID 46235734 MS 34 15

CA 26 75

NB 21 15 Bare ground studies. Broadcast at 150 g a.e./ha. Under review. Carryover of residues ranged from 0% to 6.2% of applied. In one study, 6.2% of applied was present after 455 days after application. MRID 46235735 ON 31 45

MB 30 30

SK 9 15

MT 35 90

AB 54 15

Aquatic field dissipation half-life State Max Aminopyralid Concentration Broadcast along shoreline for 225-foot

and 15-ft swath width (12ft of shoreline and 3ft into waterbody) of flowing waterbody. Application rate MRID 48939201 Water μg/L Sed. μg/kg Soil μg/kg

### Page 12 of 63

Parameter Value Description/Comments 1,2 Source

OR 32.9 14.9 333 was 0.11 lbs a.e./A.

FL 32.3 1.13 115

State Max DT 50 (days) Max Aminopyralid Concentration Broadcast at 0.036 lbs a.e/A to ponds.

Caged catfish, sunfish, clam, and crayfish were exposed and residues were measured. Max aminopyralid concentration in sediment was 4.4 μg/kg. MRID 48939202 Water μg/L Tissue μg/kg

TX 14.6 198 6.8

IN 12.9 114 30.1

Fish Bioconcentration

Fish bioconcentration factors (steady-state); depuration rate No data. -- --

Analytical Methods

ECM/ILV: Water Acidify>SPE extraction with

derivitization Detection with HPLC/MS/MS (Method GRM 01.32) Aminopyralid LOD 0.01 μg/L and LOQ = 0.05 μg/L MRIDs: 46235601 (ECM), 46235713 (ILV)

Acidify>SPE extraction with derivitization Detection with HPLC/MS/MS Aminopyralid LOQ=0.05 μg/L MRID 47572602 (ECM)

ECM/ILV: Soil Shake in methanol/2 N sodium

hydroxide (90:10) solution> SPE Detection with HPLC/MS/MS Aminopyralid LOQ = 0.001 μg/g MRID 47572602 (ECM)

Shake 2x in acetonitrile/1 N hydrochloric acid (90:10)>dry>reconstitute in 1 N HCl> 96-well SPE plate>derivatization Detection with HPLC/MS/MS (Method GRM 2.34) Aminopyralid LOQ=0.0015 μg/g MRIDs: 46235602 (ECM), 46235715 (ILV)

Storage Stability Aminopyralid stable in soil at -

20 o C for 194 days. Not reviewed MRID 46235720

Spray Drift -- Not reviewed MRID 46235834

1 All estimated values were estimated according to “ Guidance for Reporting on the Environmental Fate an d Transport of the Stressors of Concern in Problem Formulations for Registration Review, Registration Review Risk Assessments, Listed Species Litigation Assessments, New Chemical Risk Assessments, and Other Relevant Risk Assessme nts ” (USEPA, 2010).
2 Volatility classifications are based on classificat ions on the Terrestrial Field Dissipation Guideline OCSPP 835.6100 (USEPA, 2008).
3 Degradation kinetics were calculated using the sing le first order decay equation using either nonlinea r regression of non-transformed data or linear regression of log-tr ansformed data. Persistence classification are base d on criteria established for the Toxic Release Inventory, which considers chemicals persistent if the half-life in water, soil, or sediment is greater than 60-days and very persisten t if the half-life is greater than 180-days 

### (USEPA, 2012a) . A half-life in air greater than 2-days is also consid ered persistent.
4 Supplemental because not all transformation product s present at greater than 10% applied radioactivity were identified and quantified.
5 Supplemental because total recovery was 85% at stu dy termination. Unextracted residues were a maximu m of 8%.

### Page 13 of 63 6 Studies were considered supplemental due to a low mass balance, or due to the presence of unextracted residues at greater than 10% applied radioactivity. Unextracte d residues were up to 24% applied radioactivity in one study.
7 Mobility classifications are based on Food & Agric ulture Organization of the United Nations (FAO) Mob ility criteria (FAO, 2000; USEPA, 2006).
8 DT 50 were measured at 60 and 120 g/ha application rates . The highest DT 50 of the two is reported.
9 Conducted on foreign soils from Greece, France, Ge rmany, and the United Kingdom.



### Based on the available studies, the main uncertaint ies in the environmental fate database are 1) aerob ic aquatic metabolism half-lives; 2) identity of the u nextracted residues in fate studies; and 3) the ide ntity of the major degradates in the aqueous photolysis stud y 11 

### . Previously, conservative assumptions ( e.g ., using the aerobic aquatic metabolism half-lives for syste ms where an aerobic environment was not maintained and assuming the unextracted residues were the pare nt), did not result in a risk concern for most taxa

. However, previously completed assessments for amino pyralid (USEPA, 2005, D301682, 2009, D361924, 2010a, D383620), indicated a risk of concern for us e of surface and/or groundwater-derived irrigation water and potential risk to terrestrial plants.

a. Transformation Products

The only major degradates ( e.g ., those present at greater than 10% applied radioa ctivity) of aminopyralid were observed in the aqueous photolysis study (MRID 46235727) and were identified as oxamic acid (CAS#471-47-6) and malonamic acid (CAS# 2345-56-4), plus unidentified 2-3 carbon chain degradates. Maximum amounts of oxamic acid and malonamic acid w ere not reported but evidence suggests they were present, along with four other residues, at a maxim um amount of 69 percent applied radioactivity. No environmental degradates other than CO 2 

### were observed in the remaining fate studies (USEPA , 2005). According to HED, neither oxamic acid nor malonamic are considered residues of concern; both chemicals are small amino acid analogs and are expected to be readily metabolized and/or rapidly excreted follow ing uptake without any significant biological effects. The structures of identified residues are listed i n Table 6

. Appendix D provides details on the maximum amount of various residues observed in fate studies.

Table 6. Structures of Aminopyralid and Its Enviro nmental Transformation Products Code Name/ Synonym/ Chemical Name/ Formula/MW/ SMILES Chemical Structure
Aminopyralid, XDE-750 IUPAC: 4-amino-3,6-dichloropyridine-2- carboxylic acid CAS: 4-amino-3,6-dichloro-2- pyridinecarboxylic acid CAS Number: 150114-71-9 SMILES: Clc1c(nc(Cl)cc1N)C(=O)O PC Code: 005100

Aminopyralid TIPA salt CAS Number: 566191-89-7 2-Pyridinecarboxylic acid, 4-amino-3,6- dichloro-, compd. with 1,1',1''-nitrilotris[2- propanol] PC Code: 005209

11 While a couple of degradates were identified in th e aqueous photolysis study, there were four unident ified degradates that may have been major degradates. Ad ditionally, the amount of oxamic acid and malonamic acid formed is not reported in the study.

### Page 14 of 63

Code Name/ Synonym/ Chemical Name/ Formula/MW/ SMILES Chemical Structure
Aminopyralid potassium salt CAS Number: 566191-87-5 2-Pyridinecarboxylic acid, 4-amino-3,6- dichloro-, monopotassium salt PC Code: 005219

Oxamic Acid CAS number: 471-47-6 SMILES: C(=O)(C(=O)O)N

Malonamic acid CAS Number: 2345-56-4 SMILES: C(C(=O)N)C(=O)O



### 6. Receptors

Table 7 and Table 8 provide a summary of the most sensitive acute and c hronic toxicity values for aminopyralid across aquatic and terrestrial taxonom ic groups, respectively. Based on the available ecotoxicity information, aminopyralid is slightly t o practically non-toxic to freshwater and estuarine fish and aquatic invertebrates, birds, mammals, and terr estrial insects on an acute exposure basis. Since n o data are available specific to aquatic-phase amphibians, freshwater fish are used as surrogates. Since no d ata are available for reptiles or terrestrial-phase amphibi ans, birds serve as a surrogate for these taxa. As expected for an herbicide, aquatic and terrestrial plants, p articularly dicotyledon species, are relatively sen sitive to aminopyralid.

a. Effects to Aquatic Organisms

Table 7. Summary of the Most Sensitive Endpoints f rom Aquatic Toxicity Studies for Technical Aminopyralid

Taxonomic Group Study

Type Surrogate Species Toxicity Value (all units in terms of acid equivalents) Acute Toxicity

Classification Source

(MRID)

Freshwater fish* Acute Rainbow Trout ( Oncorhynchus mykiss ) LC 50 = >100 mg/L Practically nontoxic 462358-14

Acute Bluegill sunfish

( Lepomis macrochirus ) LC 50 = >100 mg/L Practically nontoxic 462358-15

### Page 15 of 63

Taxonomic Group Study

Type Surrogate Species Toxicity Value (all units in terms of acid equivalents) Acute Toxicity

Classification Source

(MRID)

Chronic Fathead minnow

( Pimphales promelas ) NOAEC = 1.36 mg/L

LOAEC = 2.44 mg/L based on decreased post-hatch survival and sublethal effects (Early Life Stage Toxicity) -- 462358-21

Freshwater invertebrates Acute Stonefly ( Pteronarcys sp. ) EC 50 = 15 mg/L Slightly toxic 400946-02

Chronic Waterflea ( Daphnia

magna ) NOAEC = 102 mg/L

LOAEC > 102 mg/L
(Full Life Cycle) -- 462358-22

Estuarine/marine fish Acute Sheepshead minnow ( Cyprinodon variegates ) LC 50 > 120 mg/L Practically nontoxic 462358-20

Chronic Sheepshead minnow

( Cyprinodon variegates ) NOAEC = 0.096

mg/L

LOAEC = 0.201 mg/L based on delayed time to hatch -- 489392-04

Estuarine/marine shrimp Acute Mysid ( Americamysis bahia ) LC 50 > 100 mg/L Practically nontoxic 462358-19

Estuarine/marine mollusk Acute Eastern oyster shell deposition ( Crassostrea virginica ) LC 50 > 89 mg/L Slightly toxic orPractically nontoxic 462358-18

Estuarine/marine invertebrate Chronic Mysid ( Americamysis bahia ) NOAEC = 101 mg/L

LOAEC > 101 mg/L -- 489392-03

Aquatic plants and algae Vascular Duckweed ( Lemna gibba ) NOAEC = 44 mg/L -- 462358-26

Nonvascular Green Algae

( Pseudokirchneriella subcapitata formerly Selenastrum capricornutum ) NOAEC = 23 mg/L -- 462358-30

Freshwater Diatom ( Navicula pelliculosa ) NOAEC = 6 mg/L -- 462358-27

Marine Diatom ( Skeletonema

costatum ) NOAEC = 13 mg/L -- 462358-28

*freshwater fish represent surrogates for aquatic-p hase amphibians.

### Page 16 of 63 b. Effects to Terrestrial Organisms

Table 8. Summary of the Most Sensitive Endpoints f rom Terrestrial Toxicity Studies for Technical Aminopyralid

Taxonomic Group Study Type Surrogate Species Toxicity Value (all units in terms of measured acid equivalents) Acute Toxicity

Classification Source

Birds 1 Acute Bobwhite quail ( Colinus virginianus ) LD 50 > 2250 mg/kg-bw Practically nontoxic 462358-08

Sub-acute dietary Bobwhite quail

( Colinus virginianus ) LC 50 > 5556 mg/kg diet Practically nontoxic 462358-10

Mallard Duck (

Anas platyrhynchos ) LC 50 > 5496 mg/kg diet Practically nontoxic 462358-11

Chronic Bobwhite quail

( Colinus virginianus ) NOAEC = 2500 mg/ kg diet

LOAEC > 2500 mg/kg diet -- 471099-01

Mallard Duck (

Anas platyrhynchos ) NOAEC = 2623 mg/ kg diet

LOAEC > 2623 mg/kg diet -- 462358-13

Mammals Acute Oral Fischer rat ( Rattus rattus ) LD 50 > 5000 mg/kg-bw Practically nontoxic 462356-03

Acute Inhalation Fischer rat

( Rattus rattus ) LD 50 > 5.5 mg/L Practically nontoxic 462356-07

Chronic CD rat ( Rattus

norvegicus ) NOAEL = 1000 mg/kg-bw

LOAEL > 1000 mg/kg-bw -- 462356-35

Insects Acute Honey bee ( Apis mellifera L. ) LD 50 = 14.5 μg/bee (contact) Practically nontoxic 462358-31

LD 50 = 14.5 μg/bee (oral) Practically nontoxic 462358-32

Terrestrial plants Seedling

Emergence Soybean ( Glycine

max ) NOAEC = 0.0008 lbs/A

EC 50 = 0.002 lb/A -- 462358-24

Onion ( Allium cepa ) NOAEC = 0.0111 lbs/A

EC 50 = 0.026 lb/A -- 462358-24

Vegetative Vigor Soybean ( Glycine

max ) NOAEC = 0.0004 lbs/A

EC 50 = 0.0007 lbs/A -- 462358-25

Onion ( Allium cepa ) NOAEC = 0.043 lbs/A

EC 50 = 0.07 lbs/A -- 462358-25

1 Birds represent surrogates for terrestrial-phase am phibians and reptiles.

### Page 17 of 63 c. Ecological Incidents

A review on November 19, 2013 of the Ecological Inc ident Information System (EIIS, version 2.1.1), which is maintained by the Agency’s Office of Pesti cide Programs, indicates a total of 39 reported ecological incidents in the United States associate d with the use of the aminopyralid acid and salt ac tive ingredients (Appendix E). All 39 of the reported i ncidents associated with aminopyralid involved dama ge to terrestrial plants and appear to be crop damage. Three of the reported incidents have occurred sin ce the time of the most recently completed assessment (USE PA, 2010a, D383620) and these were associated with applications to pasture, rights-of-way, and soybean s. The certainty categories 12 

### regarding the likelihood that the use of aminopyralid caused the 39 incident s ranged from unlikely (1 incident, 3%), possible (31 incidents, 86%), and probable (6 incidents, 15%). A summary of incident data is con tained in Appendix E

. A large proportion of reported incidences indicate damage to a variety of crops from the use of compos t (13 incidents, 33%). Other causes included direct application (4 incidents), spray drift/runoff (7 in cidents), or were not reported (9 incidents). Compost may be a cause of ecological incidents due to the potenti al persistence and toxicity of aminopyralid to terrest rial plants. For example, composted manure contain ing aminopyralid residues was used in gardens in Februa ry, 2009 and was incorporated on the date of planti ng in May, 2009. Two different incidents in NC were e ach connected with the same load of composted manure (I021 002-005 and I02076 1-001). One incide nt involved a commercial organic vegetable farm in NC, while the other was a residential organic garde ner. The chain of events was similar for both of t he incidents, i.e ., aminopyralid was used on hay, hay was sold to a horse stable, and subsequently horse manure was used by organic tomato growers.

A similar incident, not yet in the EPA EIIS databas e, is reported in the Bitterroot Valley of Montana (Graves, 2009; Sakariassen, 2009). Aminopyralid-co ntaminated manure was inadvertently applied to gardens, resulting in damage to potatoes and other vegetable crops. Tomato and potato damage was reported to the Montana Extension services in 2009. Cow manure samples used as the source of compost tested positive for the presence of aminopyralid an d damage to plants was consistent with that observe d due to exposure to plant growth regulators. More r ecently, the use of Green Mountain Valley compost contaminated with aminopyralid damaged tomato and o ther broadleaf garden plants. The source of the aminopyralid was manure from horses that had inadve rtently consumed aminopyralid residues in feed. The contamination led the technical registrant (Dow AgroSciences) to voluntarily change its labeling o f the chemical, off-labeling its use on pastures in N ew England or for any purpose in New York. An additional incident in Kentucky (1017958-011) repor ts that six acres of tobacco were adversely affecte d by spray drift at a distance of 200 yards from a label ed use of a formulated product containing aminopyra lid and 2,4 D.

12 The Ecological Incident Information System (EIIS) u sed by EPA to store incident data relies on the fol lowing certainty indices:

• Highly Probable : (residues detected in affected organisms and othe r lines of evidence support cause)

• Probable: (residues were not measured or the measured residu es were not sufficient to be considered toxic, but pesticide was used in close proximity and would be capable of exerting such an effect)

• Possible : multiple pesticides were used in close proximity and any of them are capable of causing such an eff ect.

• Unlikely: there are no measured residues and the observed e ffects are not consistent with those caused by pest icides used in the area or there was no pesticide use know n in the area.

• Unrelated: effects observed in the incident are unrelated to pesticide use.

### Page 18 of 63

7. Exposure Pathways of Concern

The environmental fate properties and use patterns of aminopyralid indicate that direct spray, spray d rift, leaching through soil (to groundwater or to surface water via subsurface lateral flow), and runoff rep resent potential transport mechanisms of aminopyralid for exposure to non-target aquatic and terrestrial organisms. Drinking water and inhalation exposure pathways were screened using the SIP (Screening Imbibition Program) and STIR (Screening Tool for In halation Risk) screening models. STIR indicated th e inhalation pathway was of low concern (no LOC excee dances are expected) for birds and mammals. Although aminopyralid is practically non-toxic to b irds and mammals on an acute exposure basis and chronic exposure resulted in no-observed adverse ef fect levels of >1000 mg/kg diet, the SIP model indicated exposure through drinking water alone was of potential concern for acute and chronic risk to birds and mammals. The avian and mammalian exposur e estimates were near or at limit doses tested for these taxa; therefore, the high solubility of amino pyralid is driving these concerns (Appendix B ) and the extent to which they are of ecological relevance is uncertain. SIP and STIR are described in detail a t http://www.epa.gov/oppefed1/models/terrestrial/inde x.htm

. Analysis of the incident data also supports the pos sibility that compost, whether through application of composted plant materials containing aminopyralid r esidues or composted manure from horses or cows fed plant material containing aminopyralid residues, ma y also be a viable exposure pathway and could resul t in potential injury to non-target plants. Aminopyrali d has many incidents in which the chemical was appl ied to pasture/hay which was eaten by ruminants. The c hemical was excreted in the animals’ manure, and th e manure was subsequently composted and used as a ter restrial plant amendment, with resultant damage to the plants. Finally, as aminopyralid is persistent and mobile, it may move into surface and groundwat er. If contaminated water were then used for irrigation, t he residues could cause damage to terrestrial plant s. Aminopyralid applied to trees that are subsequently composted could conceivably cause damage to terrestrial plants similar to that caused by compos ted manure.

8. Analysis Plan

a. Stressors of Concern

i. Ecological Risk Assessment

The stressors of ecological concern for terrestrial organisms are aminopyralid acid and unextracted residues given that the nature of the unextracted r esidues is uncertain. The only two transformation products observed in fate studies were oxamic acid and malonomic acid. As discussed earlier, these a re amino acid derivatives and are not expected to be o f concern. EFED will use a total toxic residues (T TR) approach for assessing risk to aminopyralid and une xtracted residues in water. EFED will also estimat e exposure for residues of aminopyralid alone, to get a better understanding of the uncertainty in expos ure due to the unextracted residues. This is consisten t with the approach taken in previous assessments completed for aminopyralid.

ii. Drinking Water

Because EFED recently introduced the PRZM-GW model for determining EDWCs in groundwater, an updated drinking water assessment will be completed . The HED will likely conduct a new dietary exposure and risk assessment if there are significa nt changes in the EDWCs. EDWCs will be calculated for residues of aminopyralid acid plus unextracted residues and for aminopyralid alone. This is consi stent with the approach taken in previous assessments for aminopyralid.

### Page 19 of 63 b. Measures of Exposure

EFED will use standard available models (identified in Table 9 ) to evaluate potential exposures to aquatic and terrestrial organisms as described at http://www.epa.gov/pesticides/science/models_db.htm

. Since the previous exposure assessments were comple ted, two main changes in standard procedures have been made:

1) The North American Free Trade Agreement (NAFTA) Guidance for Evaluating and Calculating Degradation Kinetics in Environmental Media (NAFTA, 2012; USEPA, 2012b) was completed. Degradation kinetics may be recalculated consistent with the updated approach. 2) A new model for estimating concentrations in ground water was developed called the Pesticide Root Zone Model – Groundwater (PRZM-GW) (USEPA, 2013a). This model will be used along with the Screening Concentration in Groundwater (SCI-GROW) m odel to estimate concentrations in groundwater.

The most up-to-date procedures and models will be u sed in the Registration Review exposure assessments

. Nonstandard modeling procedures that may be used in the risk assessment are discussed below. In the absence of data to the contrary, the T-REX model wi ll rely on a 35-day foliar dissipation rate value.

Aquatic Assessment for Residential and Rights-of-Wa y

EFED is currently exploring methods to assess urban and residential uses on a national basis. At the present time, EFED considers the use of the impervi ous scenario (a PRZM modeling scenario) as the most suitable available modeling approach for impervious runoff. This procedure was originally developed f or the assessments completed for endangered species in California. 13 

### The PRZM impervious scenario may be used in the tier II coupled aquatic models PRZM/EXA MS along with a residential or other suitable scenario such as rights-of-way (ROW) to obtain esti mated environmental concentrations (EECs). The conceptual model for the residential scenario integ rates simultaneous modeling of the individual use scenario with an impervious scenario. This approac h assumes that no watershed is completely covered b y either the 1⁄4-acre lot (the basis for the residentia l scenario) or undeveloped land (the basis for the ROW scenario) for residential and ROW use patterns; the refore, differential amounts of runoff will occur w ithin the watershed. The impervious scenario was develop ed to represent the paved areas within a watershed not including roads, parking lots, sidewalks, and b uildings outside the 1⁄4-acre lot (the 1⁄4-acre lot sce nario accounts for impervious surfaces such as buildings within the represented area). By modeling a separa te scenario for impervious surfaces, it is also possib le to estimate that amount of exposure that could o ccur when the pesticide is over-sprayed onto this surfac e. Using two scenarios in tandem requires postprocessing of the modeled output in order to derive a weighted EEC that represents the contribution of both the pervious ( i.e. , residential and ROW scenarios) and the impervious surfaces. Exposure from both scenarios can also be weighted and aggregated. The daily time series from each model run from the tim es series file (NAME_TS.out) generated from the PRZM g raphical user interface (PE5.pl) residential and impervious surface scenarios are combined using Mic rosoft ® 

### Excel. The time-series data are weighted based on percentage of impervious surface, the perc entage of the pervious surface treated, and an adju sted time series is created. Rolling averages for the r elevant durations of exposure ( e.g. , 21-day and 60-day averages) are calculated, and the relevant one-in-t en year return EEC is generated from these distribu tions.

Applications Directly to Water

The Pesticides in Flooded Applications Model (PFAM; http://www.epa.gov/oppefed1/models/water/ ), which models applications to flooded areas ( e.g ., rice paddies), will be used to estimate aquatic EECs for

13 http://www.epa.gov/espp/litstatus/effects/redleg-fr og/

### Page 20 of 63

direct applications to water. Information from aqu atic dissipation studies will be used to supplement modeled EECs.

Irrigation Water

EFED does not currently have a standardized methodo logy for determining risk to non-target plants from applications of irrigation water where surface or g roundwater has been contaminated by a pesticide app lied to crops. However, EFED anticipates that an irriga tion water analysis will be conducted at the time o f the risk assessment using exposure values generated fro m currently available models such as PRZM/EXAMS for surface water or PRZM-GW for groundwater exposu res. This approach will be used to determine a depth (in inches) of irrigation water on a one-acre field necessary to cause an LOC exceedance to terrestrial plants and compared with representative cultural practices to characterize the potential r isk associated with this exposure scenario.

Compost

Analysis of the incident data also supports the pos sibility that compost, whether through application of composted plant materials containing aminopyralid r esidues or manure from horses or cows fed such plan t material, may also be a viable exposure pathway and could result in potential injury to non-target pla nts because of the compound’s persistence. A proposed methodology for evaluating the effects of composted plant material with aminopyralid residues on non-ta rget terrestrial plants is not currently available, but will be investigated at the time of the risk assessment. Methods for analyzing residue levels in compost a re also needed.

Applications Directly to Trees

Applications to individual trees can result in abso rption and translocation of aminopyralid from the s ite of application throughout the tree. Birds, mammals, a nd terrestrial invertebrates may be exposed through ingestion of leaves, seeds, pollen, or other edible portions of the tree. Leaves containing aminopyra lid may fall onto the ground or into water resulting in mov ement of aminopyralid to soil and water. Finally, trees treated with aminopyralid may be used as compost. There is no currently approved model for estimating potential exposure to organisms from tree injection , cut-stump treatment, hack and squirt method, and frill and girdle methods. A screening-level estimate of exposure will be completed for this assessment. Th e method used to estimate exposure is discussed in a recently completed assessment in EFED, and the scre en is based on the following assumptions (USEPA, 2010b , D383620; 2010a, D381025):

(1) Aquatic Risk Assessment

a. The total mass of chemical applied to the trees on one acre is assumed to enter a 20,000,000 L water body directly; EEC = total mass of chemical applied to trees on one acre/ 20,000,000 L.

b. EEC = those estimated in GENEEC for broadcast uses at an assumed maximum application rate

(2) Concentration of chemical in leaves

a. Leaf concentration may be estimated by assuming tha t 100% of the chemical is translocated to the leaves. Leaf mass may be estim ated using allometric equations developed for blue oak trees presented by the USDA Forest Service (Karlick and McKay, 2002). EEC = total mass of chemical applied / leaf mass on tree.

This exposure estimate approach is not a standard a pproach, thus assumptions and methods are expected to be further developed and refined when the risk asse ssment is completed.

### Page 21 of 63

Drinking Water for Ecological Organisms

Screening-level calculations using SIP have suggest ed that drinking water exposure may be significant for terrestrial organisms. This exposure pathway may b e further considered at the time of the risk assess ment ( Appendix B ).

Table 9. List of the various models and the related taxa for which the models will be used.

Environment Taxa of

Concern Exposure

Pathway Model(s) or

Pathway Link

Aquatic Fish/

Invertebrates / Plants Runoff and spray

drift to water PRZM, EXAMS http://www.epa.gov/oppefed1/models/ water/ Direct application
to water PFAM http://www.epa.gov/oppefed1/models/ water/

Terrestrial Vertebrate Residues in/on dietary items T-REX (dietary item) http://www.epa.gov/oppefed1/models/ terrestrial/trex/trex_v1_5_webversion. xlsm

Plant Runoff and spray

drift to plants TerrPlant (Run-off) http://www.epa.gov/oppefed1/models/ terrestrial/index.htm#terrplant Residues in irrigation water Results from Aquatic

Models http://www.epa.gov/oppefed1/models/

water/
Residues in compost To be determined

Human Health EDWC Vertebrate Surface Water PRZM, EXAMS http://www.epa.gov/oppefed1/models/ water/ Groundwater SCIGROW

PRZM-GW

All Environments All Spray Drift AgDRIFT (Spray drift) http://www.agdrift.com/AgDRIFt2/Do

wnloadAgDrift2_0.htm AGDISP (Spray drift) http://www.continuumdynamics.com/pr-agdisp.html



### i. Available Monitoring Data

The Agency is aware of pesticide monitoring conduct ed by federal and state agencies. This information will be considered in the assessment, to the extent that data on aminopyralid are available.

c. Measures of Effect

The most sensitive toxicity data presented in Secti on 6 of this problem formulation will be used to calculate risk quotients for the respective taxa. Any additional information submitted by the registr ant or found in the open literature prior to conduct of th e risk assessment will also be considered. The ope n literature studies are identified using EPA’s ECOTO Xicology database (ECOTOX) (USEPA, 2009a), which employs a literature search engine for locati ng chemical toxicity data for aquatic life, terrest rial plants, and wildlife. The evaluation of both sourc es of data that meet the Agency’s standard for incl usion in risk assessments can also provide insight into t he direct and indirect effects of pesticides on bio tic communities from loss of species that are sensitive to the chemicals, and from changes in structure an d functional characteristics of the affected communit ies.

9. Endangered Species Assessments

Consistent with the Agency’s responsibility under t he Endangered Species Act (ESA), the Agency will

### Page 22 of 63

evaluate risks to listed species from registered us es of pesticides in Registration Review. The proce ss for evaluating potential risks to listed species is fur ther described at http://www.epa.gov/oppfead1/endanger/litstatus/risk asses.htm

. 10. Endocrine Disruptor Screening Program

Under Federal Food Drug and Cosmetic Act (FFDCA) se ction 408(p), the Agency must screen all pesticide chemicals for potential endocrine disrupt or activity. Between October 2009 and February 201 0, EPA issued test orders/data call-ins for the first group of 67 chemicals, which comprises 58 pesticide active ingredients and 9 inert ingredients. The he rbicide aminopyralid is not among the group of 58 pesticide active ingredients on the initial list to be screened under the EDSP. For further informati on on the status of the EDSP, the policies and procedures , the list of 67 chemicals, future lists, the test guidelines and the Tier 1 screening battery, please visit our website: http://www.epa.gov/endo/

. 11. Preliminary Identification of Data Gaps

a. Environmental Fate

Table 10 identifies environmental fate studies by MRID that offer data for each guideline requirement, as well as study classifications and whether or not fu rther data are needed in order to support risk asse ssment.

Table 10. Submitted Environmental Fate Data and St udy Classifications for Aminopyralid

OCSPP Guideline Data Requirement Submitted Studies (MRID) Study

Classifications Are data

needed to conduct risk assessment? Justification and Assumptions

EPA will Make in Absence of Data
835.2120 Hydrolysis 46235726 Acceptable No --

835.2240 Aqueous photolysis 46235727 Supplemental No Not all degradation products over 10%AR were individually identified and quantified in all sampling intervals. Available data are adequate for the risk assessment and to calculate an aqueous photolysis rate for aminopyralid.

835.2410 Soil photolysis 46235728 Supplemental No Supplemental due to loss in material balance of the irradiated samples and variability in material balance in dark samples. Available data are adequate to calculate a soil photolysis rate.

835.2370 Photodegradation

in Air No Data -- No --

### Page 23 of 63

OCSPP Guideline Data Requirement Submitted Studies (MRID) Study

Classifications Are data

needed to conduct risk assessment? Justification and Assumptions

EPA will Make in Absence of Data

835.4100 Aerobic soil

metabolism 46235729 Supplemental

Not at this time. There is uncertainty in the identity of the unextracted residues. Because there was no risk to aquatic taxa or for human health drinking water in previous assessments when unextracted residues were assumed to be parent, data to reduce this uncertainty are not required. Additionally, the most recently completed risk assessment indicated that assuming that the un-extracted residues were parent had little impact on EECs. 47911201 Supplemental

47925801 Acceptable

835.4200 Anaerobic soil

metabolism No data. -- No

835.4300 Aerobic aquatic

metabolism 46235731 Supplemental Yes (in support of current and proposed uses) Test systems were moderately to

strongly reducing throughout most of the study. In the absence of additional data, a value of 2x the aerobic soil metabolism input value will be used as the model input. Having additional data will reduce uncertainty in the potential for risk to terrestrial plants from residues in irrigation water for terrestrial uses. For applications directly to water, this study will reduce the uncertainty for the risk assessment for aquatic and terrestrial plants.

835.4400 Anaerobic aquatic

metabolism 46235730 Acceptable No --

835.1230 835.1240 Adsorption/

desorption and leaching 46235732 Supplemental No Data are available on 8 soils. Typically, data are available on 4 soils and 1 sediment. However, data are not available with a test soil system <1% organic matter content. Available sorption coefficients will be used in the risk assessments. There will be some uncertainty on whether sorption coefficients in sediment may be different than those found in soils.

835.1410 Volatility –

laboratory No data. -- No Not expected to be volatile under normal use conditions based on low vapor pressure and Henry’s Law Constant.

835.6100 Terrestrial field

dissipation 46235734 Supplemental No --

46235735 Under Review

835.6200 Aquatic field

dissipation 48939201 Supplemental No Storage stability study not available for water. Field spike data are available and some samples had low recoveries (60-70%)..

### Page 24 of 63

OCSPP Guideline Data Requirement Submitted Studies (MRID) Study

Classifications Are data

needed to conduct risk assessment? Justification and Assumptions

EPA will Make in Absence of Data

48939202 Supplemental Application rate lower than that proposed. A storage stability study was not available for water.

850.6100 Analytical method

for soil or sediment* 47572602 Acceptable

No Submitted studies will likely be adequate to serve as the analytical method for soil. The LOQ of 0.001 μg/g-soil (1.0 μg/kg-soil) is sufficient to cover the lowest measured terrestrial plant endpoint of 0.0004 lbs a.i./A (2 μg/kg-soil) assuming a 1.5 g/mL soil density and six-inch soil depth (MRID 46235824). 46235602 (ECM 4 ) 46235715 (ILV 3 ) Acceptable

Analytical method for water* 46235601

(ECM 4
46235713 (ILV) Acceptable

No Submitted studies will likely be adequate to serve as the analytical method for water. The lowest aquatic endpoint is 6 mg/L for a diatom (MRID 46235827). The limit of quantitation (LOQ) of 0.05 μg/L is low enough to cover the risk concern in water. 47572602 Acceptable

Analytical method for compost Not submitted -- Yes An ECM 4 and ILV 3 are needed to facilitate monitoring of residues of aminopyralid in compost. The incidents from the use of contaminated compost support the need for this ECM 4

. 850.1730 Fish

bioconcentration None

submitted -- No Based on a K ow <-1.76

Non-guideline Compost

Dissipation Study None

submitted -- Yes Data are needed to understand the potential risk to terrestrial plants from residues in compost. Data are needed to understand degradation in compost. A protocol should be submitted prior to initiation of the study.

### Page 25 of 63

OCSPP Guideline Data Requirement Submitted Studies (MRID) Study

Classifications Are data

needed to conduct risk assessment? Justification and Assumptions

EPA will Make in Absence of Data

835.7100 Prospective

Groundwater Monitoring Study None

submitted -- Yes Additional data are recommended to better understand the potential for risk due to residues of aminopyralid in groundwater. Studies that would be useful include a prospective groundwater monitoring study or studies to refine groundwater modeling inputs for the PRZM-GW model. A prospective groundwater monitoring study could be used to determine where groundwater concerns were likely to occur and whether what we predict based on laboratory data, is observed in the fie ld. Additionally, it could be used to determine vulnerability of different areas. Data to refine inputs to PRZM-GW may be used to refine modeling estimates of groundwater concentrations. Studies may involve understanding sorption or degradation in subsurface environments. It is recommended that a protocol be submitted, prior to conducting any of these studies. In the absence of more suitable inputs or scenarios, EECs generated from PRZM-GW in the same fashion as EDWCs for groundwater used as drinking water, will be used to characterize risks to terrestrial plants from residues in irrigation water obtained from groundwater sources. * The Agency has received studies and/or waiver req uests that are currently under review.
1 Target limit of quantitation (LOQ) for irrigation water in mg/L= Toxicity Endpoint for terrestrial pl ant lb a.i./Acre × (453,592 mg/lb) × (Acre-in/102,790 L water). The l owest terrestrial plant toxicity endpoint reported is a No Observed Adverse Effect Concentration of 0.0004 lb a.i./A for soybean ( Glycine max ) (MRID 462358-25).
2 The two submitted methods on water are essentially the same except for the mobile phase. Therefore, the ILV submitted will cover both methods.
3 ILV=independent laboratory validation
4 ECM=environmental chemistry method



### b. Effects

Table 11 and 12 identify ecological effect studies by MRID that of fer data for each guideline requirement, as well as study classifications and whether or not further data are needed in order to support risk assessment. The database for the aminopyralid TGAI is relatively complete. However, a number of Typical End-Use Products (TEP) are required for ris k assessment because i ) direct application to open water can be expected based on broadly-categorized use sites captured by the product labels and the

### Page 26 of 63

recently proposed aquatic use (as described in Sect ion 3); and ii ) some of the TEPs contain active ingredients with similar mode-of-actions compared t o aminopyralid and the combinations may result in unexpected interactions.

o The 40 CFR Part 158 (40 CFR 2012) identifies data r equirements for conventional pesticides, including those pesticides applied directly to wate r and/or those known to be phytotoxicants such as aminopyralid. Of the studies required to s upport the aquatic use of aminopyralid that is currently under review, the following studies ar e not available in the existing database and are therefore necessary for conducting an ecologica l risk assessment. The studies following studies should be conducted using representative pr oducts that contain i ) aminopyralid and 2,4-D; ii ) aminopyralid and triclopyr; iii ) aminopyralid and clopyralid; iv ) aminopyralid and metsulfuron; and v ) aminopyralid and fluroxypyr-1-methylheptyl ester.

• Freshwater invertebrate acute toxicity (OCSPP Gu ideline 850.1010) • Tier II terrestrial plant vegetative vigor (OCSP P Guideline 850.4150) and seedling emergence (OCSPP 850.4250). The studies should inc lude the most sensitive species (Dicot: soybean, lettuce; Monocots: onion), as indi cated in currently available data. • Aquatic plant growth (freshwater diatom, Navicula pelliculosa) (Tier II) (OCSPP Guideline 850.4500)

o Additional study requirements based upon the curren t and proposed use patterns include:

• 

### cyanobacteria toxicity study (OCSPP 850.4550) using a TEP that contains aminopyralid only due to the potential for direct a pplication to open water sources. Although terrestrial plants appear to be the most s ensitive taxa to aminopyralid toxicity, the lack of an acceptable study on cyanob acteria is an uncertainty.

• 

### Non-standard study (OECD 237) to assess TGAI aminop yralid toxicity to developing bee larva.

Based on the weight of evidence ( i.e., that uses of aminopyralid did not previously result in acute risk concerns for terrestrial and aquatic vertebrates or invertebrates, and that nonvascular plants are not the most sensitive aquatic plant species for aminopyral id), the previously listed studies will likely be s ufficient to evaluate the potential for risk for the proposed use patterns. If the studies indicate the formula ted products are more toxic compared to the TGAI, then it will be assumed that the toxicity to other taxa will be increased as well.

Furthermore, the mysid life cycle with TGAI (OCSPP 850.1350) and the avian acute oral toxicity for a passerine using TGAI (OCSPP 850.2100) have previous ly been triggered based on other aminopyralid uses but previous risk assessments have indicated t hey are not required to preclude risk. It is likel y that the same conclusion will be reached for current and pro posed use under review.

available chronic studies on invertebrates and prel iminary estimates of exposure suggest direct risk to the TGAI alone at current expected exposure leve ls will be low. When the risk assessment is completed, it may be possible to preclude direct ri sk to these species based on available data; and.

an acute oral toxicity study with a passerine speci es was a data gap identified in a previous risk assessment (USEPA, 2010a). Data for passerine speci es are required under the new 40 CFR Part 158 (Oct. 26, 2007). Part 158 data requirements spe cify that avian acute oral toxicity data (OCSPP Guideline 850.2100) be submitted for either a malla rd duck or bobwhite quail and a passerine species. However, there were no mortalities in acc eptable acute studies in the bobwhite quail or subchronic dietary studies in the bobwhite quail an d mallard duck. Furthermore, there have been no incidents involving avian species according to t he Avian Incident Monitoring System (AIMS). The previous risk assessments have not identified a ny risk to avian species and we do not expect

### Page 27 of 63

this risk conclusion to change for the proposed use . Therefore, we are not requesting these data at this time.

Table 11. Submitted Aquatic Ecological Effects Dat a and Study Classifications for Aminopyralid.

OCSPP Guideline Data

Requirement Study

Type Submitted

Studies (MRID) Study Classification Are data needed to conduct risk assessment Justification and

Assumptions EPA will Make in Absence of Data - Some Example texts are include

850.1010 Freshwater

invertebrate toxicity Acute 46235817 Acceptable

No

-- 48939301 Under Review

48939401 Under Review

48939501 Under Review

850.1025 850.1035 850.1045 850.1055 Saltwater

invertebrate toxicity Acute 46235818 Acceptable

No -- 48939302 Under Review

48939502 Under Review 46235819 Acceptable

48939303 Under Review

48939503 Under Review

850.1075 Freshwater fish Acute 46235814 Acceptable

No -- 46235815 Supplemental 46235816 Supplemental

48939304 Under Review

48939402 Under Review

48939504 Under Review

850.1075 Saltwater fish Acute 46235820 Acceptable No -- 48939305 Under Review

850.1300 Freshwater

invertebrates life cycle Chronic 46235822 Acceptable No -- 46235823 Supplemental

850.1350 Saltwater

invertebrates life cycle Chronic 48939203 Acceptable No --

850.1400 Freshwater fish

early-life stage Chronic 46235821 Supplemental No --

850.1400 Saltwater fish

early-life stage Chronic 48939204 Acceptable No --

850.1500 Freshwater fish

full life cycle Chronic (None) (N/A) No --

850.1735 850.1740 10-day Sediment

Toxicity Test Subacute (None) (NA) No

850.4400 Aquatic plant

Toxicity Test using Lemna minor

. -- 46235826 Acceptable No

--

850.5400 Algal toxicity 46235827 Supplemental

No -- 48939403 Under Review 46235828 Acceptable

### Page 28 of 63 47109902 Supplemental

850.4550 Cyanobacteria 46235829 Unacceptable Yes Due to the lack of an acceptable study, EFED is requesting a study using the TGAIo--



### Table 12. Submitted Terrestrial Ecological Effects Data for Aminopyralid.

OCSPP Guideline Data

Requirement Study Type Submitted Studies (MRID) Study

Classifications Are data

needed for risk assessment Current Additional Data

Need

850.2100 Avian oral

toxicity Acute 46235808 Acceptable

No -- 46235809 Supplemental

Passerine Acute (None) (NA) No Acute avian oral toxicity data are required for either one waterfowl or one upland game species and one passerine species under the 40 CFR Part 158 (2010) data requirements for conventional pesticides with outdoor uses . However, there were no mortalities in acute or subchronic dietary studies including bobwhite quail and mallard duck and it is likely that results of a passerine species will be similar. Therefore, this study is not being required.

850.2200 Avian dietary

toxicity Subacute 46235810 Acceptable

No -- 46235811 Acceptable

850.2300 Avian

reproduction Chronic 46235812 Supplemental

No -- 46235813 Acceptable

47109901 Acceptable

Nonguideline Avian inhalation Acute (None) (NA) No Aminopyralid has a vapor point of 1.94 x10 -10 Torr and is not expected to volatilize. EFED’s STIR model further indicated that inhalation is not likely to be a significant pathway for exposure. Therefore, this study is not required at this time.

850.3020 Honey bee acute

contact toxicity Acute 46235831 Acceptable No --

### Page 29 of 63

OCSPP Guideline Data

Requirement Study Type Submitted Studies (MRID) Study

Classifications Are data

needed for risk assessment Current Additional Data

Need

46235832 Supplemental

Honey bee larval toxicity test (OECD 237) Acute (None) (NA) Yes This study is being required to assess the toxicity of aminopyralid to developing bee larva

850.3030 Honey bee

residue on foliage -- (None) (NA) No The LD 50 for the honey bee acute contact study was 14.5 μg a.i./bee, above the trigger for the honey bee residue on foliage study of 11 μg/bee. Furthermore, aminopyralid has not been highlighted as a pervasive pesticide in bee colonies and oral exposure will be negligible based on the use pattern. Therefore, this study is not being required at this time.

850.3040 Field testing for

pollinators -- (None) (NA) No See explanation for Honey bee residue on foliage.

850.4100 Seedling

Emergence and Seedling Growth -- 46235824 Supplemental Yes New tier data using representative TEPs are required for the most sensitive species (i.e., soybean, lettuce, and onion) 850.4250 Vegetative

Vigor -- 46235825 Supplemental Yes
* The Agency has received studies and/or waiver req uests that are currently under review.



### Table 13. Summary of Additional Data Requirements for Representative Typical End-Use Products Containing Multiple Active Ingredients.
OCSPP Guideline Data Requirement

Nonstandard (OECD 237) Honey bee larval toxicity test This study using TGAI is required to assess aminopy ralid toxicity to developing bee larva

850.1010 Freshwater invertebrate acute toxicity* Data are needed on a representative products that c ontain i ) aminopyralid and 2,4-D; ii ) aminopyralid and triclopyr; iii ) aminopyralid and clopyralid; iv ) aminopyralid and metsulfuron; and v ) aminopyralid and fluroxypyr-1-methylheptyl ester. 850.4150 Terrestrial plant vegetative vigor (soybea n, lettuce,

onion)* 850. Seedling Emergence (soybean, lettuce, onion)

850.4500 Aquatic plant growth (freshwater diatom, Navicula

pelliculosa ) (Tier II)*

850.4550 Aquatic plant growth for cyanobacteria* TE P containing aminopyralid only

8501075 Freshwater fish acute toxicity Several stud ies with representative TEPs are triggered by proposed aquatic use pattern. However, since the r epresented taxa do not represent the most sensitive species an d did not result in risks of concern in prior assessments, the studi es listed above will likely be sufficient to evaluate potential ris k for the proposed use patterns. 850.4400 Aquatic plant toxicity using Lemna sp. 850.1035 Acute toxicity mysid 850.1075 Acute toxicity estuarine/marine fish 850.1025 Acute toxicity estuarine/marine mollusc

### Page 30 of 63

850.1350 Mysid life cycle with TGAI Previous risk assessments listed these studies as d ata gaps, however, they are not required to preclude risk. 850.2100 Avian acute oral toxicity for passerine wi th TGAI * The Agency has received studies and/or waiver req uests that are currently under review



### 12. References

Armitage, J. M., & Gobas, F. A. P. C. 2007. A terr estrial food-chain bioaccumulation model for POPs. Environmental Science and Technology, 41 , 4019-4025. FAO. 2000. Appendix 2. Parameters of pesticides th at influence processes in the soil. In FAO Informat ion Division Editorial Group (Ed.), Pesticide Disposal Series 8. Assessing Soil Contam ination. A Reference Manual . Rome: Food & Agriculture Organization of the Unit ed Nations (FAO). Available at http://www.fao.org/DOCREP/003/X2570E/X2570E06.htm (Accessed July 10, 2009). Graves, M. 2009. Residual Herbicide Can Damage Sen sitive Garden Plants. Montana Pesticide Bulletin, December 2009

. HRAC. 2005. Classification of Herbicides According to Mode of A ction

, Herbicide Resistance Action Committee (HRAC) : Herbicide Resistance Action. Available at http://www.hracglobal.com/Publications/Classificati onofHerbicideModeofAction/tabid/222/Defau lt.aspx (Accessed October 23, 2013). Karlick, J. F., & McKay, A. H. 2002. Leaf Area Index, Leaf Mass Density, and Allometric Relationships Derived From Harvest of Blue Oaks in a California O ak Savanna . General Technical Report PSW-GTR-184. USDA Forest Service. NAFTA. 2012. Guidance for Evaluating and Calculating Degradation Kinetics in Environmental Media

. December 2012. NAFTA Technical Working Group on Pes ticides. Available at http://www.epa.gov/oppfead1/international/naftatwg/ guidance/degradation-kin.pdf (Accessed December 16, 2013). Sakariassen, A. 2009. Sullied soil : Missoula Independent Free Thinking. Blog. Avail able at http://missoulanews.bigskypress.com/IndyBlog/archiv es/2009/08/25/sullied-soil (Accessed USEPA. 2004.D306647. EFED Reduced Risk Screening Memo for Aminopyralid. D306647 . October 19, 2004. Environmental Fate and Effects Division. Off ice of Pesticide Programs. USEPA. 2005.D301682. Aminopyralid Section 3: Environmental Fate and Eff ects Risk Assessment. D301682, D301691, D301658, D306825 . May 10, 2005. Environmental Fate and Effects Division, Office of Pesticide Programs. United Sta tes Environmental Protection Agency. USEPA. 2005. Aminopyralid: Tier I Estimated Drinking Water Conc entrations (EDWC) for Use in the Human Health Risk Assessment . D301682. February 3, 2005. Environmental Fate an d Effects Division, Office of Pesticide Programs, United Stat es Environmental Protection Agency. USEPA. 2006. Standardized Soil Mobility Classification Guidance . Memorandum From S. Bradbury to E. F. a. E. Division. April, 21, 2006. Environmnental Fate and Effects Division. Office of Pesticide Programs. Office of Prevention, Pesticides, and To xic Substances. United State Environmental Protection Agency. USEPA. 2008. Fate, Transport, and Transformation Guidelines. OPP TS 835.6100 Terrestrial Field Dissipation . EPA 712-C-08-020. October 2008. Office of Preven tion, Pesticides, and Toxic Substances. Available at http://www.epa.gov/opptsfrs/publications/835_6100.p df (Accessed July 30, 2009). USEPA. 2009.D361924. Ecological Risk Assessment for the Triisopropanolam ine Salt of Aminopyralid Section 3 New Uses on Field Corn and Field Corn gro wn for Ensilage. D361924 . October 22, 2009. Environmental Fate and Effects Division. Off ice of Pesticide Programs. USEPA. 2009a. ECOTOXicology Database

, United States Environmental Protection Agency (USEP A)

. Available at http://cfpub.epa.gov/ecotox/ (Accessed June 19, 2009). USEPA. 2009b. Guidance for Selecting Input Parameters in Modeling the Environmental Fate and Transport of Pesticides, Version 2.1 . Available at http://www.epa.gov/oppefed1/models/water/input_para meter_guidance.htm (Accessed November 12, 2010).

### Page 31 of 63

USEPA. 2009c. SAP Minutes No. 2009-01. A set of Scientific Issue s Being Considered by the Environmental Protection Agency Regarding: Selecte d Issues Associated with the Risk Assessment Process for Pesticides with Persistent, Bioaccumulative, and Toxic Characteristics. October 28-31, 2008. January 29, 2009. FIFRA Scientific Advisory Panel . Office of Science Coordination and Policy. Available at http://www.epa.gov/scipoly/sap/meetings/2008/102808 _mtg.htm (Accessed July 9, 2009). USEPA. 2010a.D383620. Ecological Risk Assessment for the Proposed Section 24C New Use of Triisopropanolamine Salt of Aminopyralid for Contro l of Herbaceous Broadleaf Weeds and Woody Plants in Forests, Non-cropland, Grazed areas , and Industrial Non-crop Areas in Arkansas . D383620. December 7, 2010. Environmental Fate an d Effects Division. Office of Pesticide Programs. Office of Chemical Safety and Pollution Prevention. United States Environmental Protection Agency. USEPA. 2010. Guidance for Reporting on the Environmental Fate an d Transport of the Stressors of Concern in the Problem Formulation for Registration Review, Registration Review Risk Assessments, Listed Species Litigation Assessments, New Chemical Risk Assessments, and Other Relevant Risk Assessments . January 25, 2010. Environmental Fate and Effects Division, . Available at http://www.epa.gov/pesticides/science/efed/policy_g uidance/team_authors/endangered_species_re registration_workgroup/esa_reporting_fate.htm (Accessed July 5, 2012). USEPA. 2010a.D381025. Section 3 Product Registration Request for Expansio n of Tree Species for Emamectin Benzoate Tree Injection Use to Control Ar thropod Pests . D381025. October 5, 2010. Environmental Fate and Effects Division. Office of Pesticide Programs. Office of Chemical Safety and Pollution Prevention. United States Env ironmental Protection Agency. USEPA. 2010b.D383620. Tier I Drinking Water Exposure Assessment for the S ection 24C (Special Local Need) New Use of Triisopropanolamine Salt of Aminop yralid for Control of Herbaceous Broadleaf Weeds and Woody Plants in Fore sts, Non-cropland,Grazed areas, and Industrial Non-crop Areas in Arkansas . D383620. December 6, 2010. Environmental Fate an d Effects Division. Office of Pesticide Programs. Office of Chemical Safety and Pollution Prevention. United States Environmental Protection Agency. USEPA. 2012a. Criteria Used by the PBT Profiler . September 4, 2012. Office of Chemical Safety and Pollution Prevention. United States Environmental P rotection Agency. Available at http://www.pbtprofiler.net/criteria.asp (Accessed September 7, 2012). USEPA. 2012b. Standard Operating Procedure for Using the NAFTA Gu idance to Calculate Representative Half-life Values and Characterizing Pesticide Degradation . November 30, 2012. Environmental Fate and Effects Division. Office of Pesticide Programs. United States Environmental Protection Agency. Available at http://www.epa.gov/oppefed1/ecorisk_ders/degradatio n_kinetics/NAFTA_Degradation_Kinetics.h
tm (Accessed December 16, 2013). USEPA. 2013.D410811. Aminopyralid Section 3 New Aquatic Use: Screen of Data Package and Identification of Data Gaps . D410811. June 3, 2013. Environmental Fate and Ef fects Division. Office of Pesticide Programs. Office of Chemical S afety and Pollution Prevention. United States Environmental Protection Agency. USEPA. 2013a. Guidance for Using PRZM-GW in Drinking Water Exposu re Assessments . December 11, 2012. Environmental Fate and Effects Division. Off ice of Pesticide Programs. United States Environmental Protection Agency. Available at http://www.epa.gov/oppefed1/models/water/przm_gw/wq tt_przm_gw_guidance.htm (Accessed January 22, 2013). USEPA. 2013b. Screening Level Estimates of Agricultural Uses of A minopyralid . Biological and Economic Analysis Division. Office of Pesticide Pr ograms. Office of Chemical Safety and Pollution Prevention. United States Environmental Protection Agency. Ware, G. W., & Whitacre, D. M. 2004. An Introductio n to Herbicides. In E. B. Radcliffe & W. D. Hutchison (Eds.), The Pesticide Book (6th ed.). Willoughby, OH: MeisterPro Information

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Resources. Available at http://ipmworld.umn.edu/chapters/whitacreherb.htm (Accessed October 17, 2013). Wood, A. 2013. Compendium of Pesticide Common Names . Available at http://www.alanwood.net/pesticides/index.html (Accessed October 17, 2013).

### Page 33 of 63

Appendix A. Bibliography of Submitted Studies

Environmental Fate

MRID Citation Reference 161-1 Hydrolysis 46235726 Cook, W. (2003) Hydrolysis of XDE-750 at pH 5, 7, a nd 9. Project Number:

020067. Unpublished study prepared by Dow AgroScien ces LLC. 45 p. 161-2 Photodegradation-water 46235727 Cook, W. (2003) Aqueous Photolysis of XDE-750 in pH 5 Buffer Under Xenon

Light. Project Number: 020066. Unpublished study pr epared by Dow AgroSciences LLC. 92 p. 161-3 Photodegradation-soil 46235728 Rutherford, L. (2004) Photodegradation of XDE-750 o n Soil. Project Number:

020080. Unpublished study prepared by Dow AgroScien ces LLC. 80 p.

162-1 Aerobic soil metabolism 46235729 Yoder, R.; Smith, K. (2002) Aerobic Soil Degradatio n of XDE-750 in Five North

American Soils. Project Number: 010091. Unpublished study prepared by Dow AgroSciences LLC. 106 p. 162-3 Anaerobic aquatic metab. 46235730 Rutherford, L.; Meitl, T. (2004) Anaerobic Aquatic Metabolism of XDE-750.

Project Number: 020052. Unpublished study prepared by Dow AgroSciences LLC. 73 p. 162-4 Aerobic aquatic metab. 46235731 Yoder, R.; Smith, K. (2003) Degradation of XDE-750 in 2 European and 1 US

Sediment and Pond Water Systems. Project Number: 02 0062. Unpublished study prepared by Dow AgroSciences LLC. 88 p. 163-1 Leach/adsorp/desorption 46235729 Yoder, R.; Smith, K. (2002) Aerobic Soil Degradatio n of XDE-750 in Five North

American Soils. Project Number: 010091. Unpublished study prepared by Dow AgroSciences LLC. 106 p. 46235732 Rutherford, L. (2002) Soil Batch Equilibrium Adsorp tion/Desorption of XDE-750.

Project Number: 010064. Unpublished study prepared by Dow AgroSciences LLC. 128 p. 164-1 Terrestrial field dissipation 46235713 Reed, R (2004) Independent Laboratory Validation of Dow AgroSciences Method GRM 01.32 - Determination of Residues of Aminopyral id in Water by Liquid Chromatography with Tandem Mass Spectrometry. Proje ct Number: 030039, ML03/1111/DOW. Unpublished study prepared by Morse Laboratories. 113 p. 46235715 Reed, R. (2004) Independent Laboratory Validation o f Dow AgroSciences Method

GRM 02.34 - Determination of Residues of Aminopyral id in Soil by Liquid Chromatography with Tandem Mass Spectrometry. Proje ct Number: 020158, ML03/1102/DOW. Unpublished study prepared by Morse Laboratories. 125 p.

### Page 34 of 63

MRID Citation Reference 46235734 Roberts, D. (2004) Terrestrial Field Dissipation of XDE-750 in the USA. Project Number: 020032. Unpublished study prepared by Dow A groSciences LLC. 158 p. 46235735 Roberts, D.; Schelle, G. (2004) Terrestrial Field D issipation of XDE-750 in Canada.

Project Number: 020031, ELECTRONIC/COPY. Unpublishe d study prepared by Dow AgroScience LLC. 302 p. 830.7050 UV/Visible absorption 46235703 Ghaoui, L. (2003) Group B: Physical and Chemical Pr operties of Aminopyralid

(XDE-750) Technical. Project Number: NAFST744, DOS3 23/024653, FAPC/013053. Unpublished study prepared by Dow Agro sciences LLC, Dow Agrosciences (New Zealand) Ltd. and The Dow Chemica l, Co. 313 p. 46235704 Cathie, C. (2003) Group B: Determination of Physica l State, Colour, Odor,

Oxidizing and Reduction Action, Flammability, Explo dability, pH, Viscosity and Density of GF-871, a Liquid End-Use Product Contain ing XR-750 TIPA. Project Number: 02/070/L. Unpublished study prepared by Dow Agrosciences (New Zealand) Ltd. 17 p. 46235705 McFarlane, J. (2003) Group B-Physical/Chemical Prop erties for GF-871, A Liquid

End Use Product Containing XR-750 TIPA. Project Num ber: NAFST788: GHF/P/2709. Unpublished study prepared by Dow Agros ciences, LLC. 5 p. 46434202 McFarlane, J. (2004) Group B-Physical/Chemical Prop erties for GF-982, A Liquid

End Use Product Containing Aminopyralid and Fluorox ypyr (Revised Report). Project Number: NAFST824. Unpublished study prepare d by Dow AgroSciences LLC. 5 p. 46434302 McFarlane, J. (2004) Group B-Physical/Chemical Prop erties for GF-1004, A Liquid

End Use Product Containing Aminopropyralid and 2,4- D. Project Number: NAFST/04/868. Unpublished study prepared by Dow Agr oSciences LLC. 5 p. 46942402 Jones, J. (2006) Group B - Physical/Chemical Proper ties for GF-1883, A Liquid End

Use Product Containing Aminopyralid and Triclopyr. Project Number: NAFST/06/098. Unpublished study prepared by Dow Agr oSciences LLC. 5 p. 47290636 McFarlane, J. (2004) Group B-Physical/Chemical Prop erties for GF-1004, A Liquid

End Use Product Containing Aminopyralid and 2,4-D. Project Number: NAFST/04/868. Unpublished study prepared by Dow Agr oSciences LLC. 5 p. 46235703 Ghaoui, L. (2003) Group B: Physical and Chemical Pr operties of Aminopyralid

(XDE-750) Technical. Project Number: NAFST744, DOS3 23/024653, FAPC/013053. Unpublished study prepared by Dow Agro sciences LLC, Dow Agrosciences (New Zealand) Ltd. and The Dow Chemica l, Co. 313 p. 46235703 Ghaoui, L. (2003) Group B: Physical and Chemical Pr operties of Aminopyralid

(XDE-750) Technical. Project Number: NAFST744, DOS3 23/024653, FAPC/013053. Unpublished study prepared by Dow Agro sciences LLC, Dow Agrosciences (New Zealand) Ltd. and The Dow Chemica l, Co. 313 p. 830.7300 Density/relative density 46235703 Ghaoui, L. (2003) Group B: Physical and Chemical Pr operties of Aminopyralid

(XDE-750) Technical. Project Number: NAFST744, DOS3 23/024653, FAPC/013053. Unpublished study prepared by Dow Agro sciences LLC, Dow Agrosciences (New Zealand) Ltd. and The Dow Chemica l, Co. 313 p. 46235704 Cathie, C. (2003) Group B: Determination of Physica l State, Colour, Odor,

Oxidizing and Reduction Action, Flammability, Explo dability, pH, Viscosity and Density of GF-871, a Liquid End-Use Product Contain ing XR-750 TIPA. Project Number: 02/070/L. Unpublished study prepared by Dow Agrosciences (New

### Page 35 of 63

MRID Citation Reference

Zealand) Ltd. 17 p.

46235705 McFarlane, J. (2003) Group B-Physical/Chemical Prop erties for GF-871, A Liquid

End Use Product Containing XR-750 TIPA. Project Num ber: NAFST788: GHF/P/2709. Unpublished study prepared by Dow Agros ciences, LLC. 5 p. 46434202 McFarlane, J. (2004) Group B-Physical/Chemical Prop erties for GF-982, A Liquid

End Use Product Containing Aminopyralid and Fluorox ypyr (Revised Report). Project Number: NAFST824. Unpublished study prepare d by Dow AgroSciences LLC. 5 p. 46434302 McFarlane, J. (2004) Group B-Physical/Chemical Prop erties for GF-1004, A Liquid

End Use Product Containing Aminopropyralid and 2,4- D. Project Number: NAFST/04/868. Unpublished study prepared by Dow Agr oSciences LLC. 5 p. 46942402 Jones, J. (2006) Group B - Physical/Chemical Proper ties for GF-1883, A Liquid End

Use Product Containing Aminopyralid and Triclopyr. Project Number: NAFST/06/098. Unpublished study prepared by Dow Agr oSciences LLC. 5 p. 47290636 McFarlane, J. (2004) Group B-Physical/Chemical Prop erties for GF-1004, A Liquid

End Use Product Containing Aminopyralid and 2,4-D. Project Number: NAFST/04/868. Unpublished study prepared by Dow Agr oSciences LLC. 5 p.

830.7370 Dissociation constants in water 46235703 Ghaoui, L. (2003) Group B: Physical and Chemical Pr operties of Aminopyralid

(XDE-750) Technical. Project Number: NAFST744, DOS3 23/024653, FAPC/013053. Unpublished study prepared by Dow Agro sciences LLC, Dow Agrosciences (New Zealand) Ltd. and The Dow Chemica l, Co. 313 p. 46235706 Hamilton, T. (2004) Amended Report for Dissociation of XDE-750

Trilsopropanolamine Salt. Project Number: DECO/GL/A L/MD/2002/004418. Unpublished study prepared by The Dow Chemical Comp any. 21 p. 46235707 Hamilton, T. (2004) Amended Report for Dissociation of XDE-750 Potassium Salt.

Project Number: GL/AL/MD/2002/004397. Unpublished s tudy prepared by The Dow Chemical, Co. 21 p. 46235706 Hamilton, T. (2004) Amended Report for Dissociation of XDE-750

Trilsopropanolamine Salt. Project Number: DECO/GL/A L/MD/2002/004418. Unpublished study prepared by The Dow Chemical Comp any. 21 p. 46235706 Hamilton, T. (2004) Amended Report for Dissociation of XDE-750

Trilsopropanolamine Salt. Project Number: DECO/GL/A L/MD/2002/004418. Unpublished study prepared by The Dow Chemical Comp any. 21 p. 830.7550 Partition coefficient (n-octanol/wat er), shake flask method 46235703 Ghaoui, L. (2003) Group B: Physical and Chemical Pr operties of Aminopyralid

(XDE-750) Technical. Project Number: NAFST744, DOS3 23/024653, FAPC/013053. Unpublished study prepared by Dow Agro sciences LLC, Dow Agrosciences (New Zealand) Ltd. and The Dow Chemica l, Co. 313 p. 830.7840 Water solubility: Column elution met hod, shake flask method 46235703 Ghaoui, L. (2003) Group B: Physical and Chemical Pr operties of Aminopyralid

(XDE-750) Technical. Project Number: NAFST744, DOS3 23/024653, FAPC/013053. Unpublished study prepared by Dow Agro sciences LLC, Dow Agrosciences (New Zealand) Ltd. and The Dow Chemica l, Co. 313 p. 830.7950 Vapor pressure

### Page 36 of 63

MRID Citation Reference 46235703 Ghaoui, L. (2003) Group B: Physical and Chemical Pr operties of Aminopyralid

(XDE-750) Technical. Project Number: NAFST744, DOS3 23/024653, FAPC/013053. Unpublished study prepared by Dow Agro sciences LLC, Dow Agrosciences (New Zealand) Ltd. and The Dow Chemica l, Co. 313 p. 835.1220 Sediment and soil absorption /desorp tion isotherm 46235732 Rutherford, L. (2002) Soil Batch Equilibrium Adsorp tion/Desorption of XDE-750.

Project Number: 010064. Unpublished study prepared by Dow AgroSciences LLC. 128 p.

835.4100 Aerobic soil metabolism 47925801 Sarff, P. (2009) Degradation of Aminopyralid in Thr ee US Soils Under Aerobic

Conditions. Project Number: 64104, 080154. Unpublis hed study prepared by ABC Laboratories, Inc. 104 p. 835.6200 Aquatic field dissipation 47971401 (2010) Dissipation and Aquatic Organism Residue Mon itoring of Aminopyralid in

Small Ponds: Protocol. Project Number: 101046. Unpu blished study prepared by Dow AgroSciences, LLC. 12 p. 47971402 (2010) Dissipation of Aminopyralid in Flowing Water Systems Under Operational

Conditions: Protocol. Project Number: NA10L1B029. U npublished study prepared by Dow AgroSciences, LLC. 9 p. 48939201 Moore, D.; Newcombe, A.; Havens, P. (2012) Dissipat ion of Aminopyralid in

Flowing Water Systems Under Operational Conditions: Final Report. Project Number: 110423. Unpublished study prepared by Agvis e Laboratories, Inc., Dow AgroSciences LLC, ARCADIS U.S., Inc. and Covance La boratories, Inc. 369p. 48939202 Newcombe, A.; Negley, T.; Havens, P. (2012) Dissipa tion and Aquatic Organism

Residue Monitoring of Aminopyralid in Small Ponds: Final Report. Project Number: 101046. Unpublished study prepared by Agvise Labora tories, Inc., ARCADIS U.S., Inc. and Dow AgroSciences, LLC. 376p. 860.1340 Residue analytical method 46235712 Reed, R. (2004) Independent Laboratory Validation o f Dow AgroSciences LLC

Method GRM 02.31 - Determination of Residues of Ami nopyralid in Agricultural Commodities by Liquid Chromatography with Tandem Ma ss Spectrometry Detection. Project Number: 020157, ML03/1110/DOW. U npublished study prepared by Morse Laboratories. 147 p. 46235714 Reed, R. (2004) Independent Laboratory Validation o f Dow AgroSciences LLC

Method GRM 03.18 - Determination of Residues of Ami nopyralid in Bovine Tissues by Liquid Chromatography with Tandem Mass Spectrome try. Project Number: 030098, ML03/1122/DOW. Unpublished study prepared b y Morse Laboratories. 130
p. 46235716 Rutherford, L.; Hastings, M. (2003) Method Validati on Report for the Determination

of Aminopyralid in Bovine Tissues by Liquid Chromat ography with Tandem Mass Spectrometry Using Dow AgroSciences LLC Method GRM 03.18. Project Number: 021327, GRM/03/18. Unpublished study prepared by Do w AgroSciences LLC. 53 p. 46235717 Olberding, E.; Hastings, M. (2004) Validation Repor t for Method GRM 02.31 -

Determination of Residues of Aminopyralid in Agricu ltural Commodities by Liquid Chromatography with Tandem Mass Spectrometry Detect ion. Project Number: 021310, GRM/02/31. Unpublished study prepared by Do w AgroSciences LLC. 61 p.

### Page 37 of 63

MRID Citation Reference 46729001 Oberling, E. (2006) A Confirmatory Technique for th e Determination of Residues of

Aminopyralid in Agricultural Commodities by Liquid Chromatography with Tandem Mass Spectrometry Detection. Project Number: GH/C/5830, GRM/02/31. Unpublished study prepared by Dow Agrosciences LLC. 25 p. 46729601 Olberding, E. (2004) Validation Report for Method G RM 02.31 - Determination of

Residues of Aminopyralid in Agricultural Commoditie s by Liquid Chromatography with Tandem Mass Spectrometry Detection. Project Nu mber: 021310. Unpublished study prepared by Dow Agrosciences LLC. 62 p. 46729602 Rutherford, L. (2003) Method Validation Report for the Determination of

Aminopyralid in Bovine Tissues by Liquid Chromatogr aphy with Tandem Mass Spectrometry Using Dow AgroSciences LLC Method GRM 03.18. Project Number: 021327. Unpublished study prepared by Dow AgroScien ces LLC. 54 p. 46729603 Reed, R. (2004) Independent Laboratory Validation o f Dow AgroSciences LLC

Method GRM 02.3.1 - Determination of Residues of Am inopyralid in Agricultural Commodities by Liquid Chromatography with Tandem Ma ss Spectrometry Detection. Project Number: 020157, ML03/1110/DOW. U npublished study prepared by Morse Laboratories. 148 p. 47572602 Wendelburg, B. (2008) Validation Report for Methods GRM 07.07 - Determination

of Residues of Aminopyralid in Agricultural Commodi ties by Liquid Chromatography with Tandem Mass Spectrometric Detec tion, GRM 07.08 - Determination of Residues of Aminopyralid in Bovine and Poultry Tissues, Milk, and Eggs by Liquid Chromatography with Tandem Mass Spectrometric Detection, GRM 07.09 - Determination of Residues of Aminopyral id in Soil by Liquid Chromatography with Tandem Mass Spectrometric Detec tion, and GRM 07.10 - Determination of Residues of Aminopyralid in Drinki ng Water, Ground Water, and Surface Water by Liquid Chromatography with Tandem Mass Spectrometric Detection. Project Number: 071121. Unpublished stud y prepared by Dow AgroSciences, LLC. 207 p. 860.1380 Storage stability data 46235719 Lindsay, D. (2004) Frozen Storage Stability of XDE- 750 in Range Land and Pasture

Grass and Hay and Wheat Straw and Wheat Grain - Int erim Report. Project Number: 030004. Unpublished study prepared by Dow AgroScien ces LLC. 50 p. 46235720 Lindsay, D. (2004) Frozen Storage Stability of XDE- 750 in Soil--Interim Report.

Project Number: 030002. Unpublished study prepared by Dow AgroSciences LLC. 41 p. 46661301 Lindsay, D. (2004) Frozen Storage Stability of XDE- 750 in Range Land and Pasture

Grass and Hay and Wheat Straw and Wheat Grain. Proj ect Number: 030004/01. Unpublished study prepared by Dow Agrosciences LLC. 59 p. 860.1400 Water, fish, and irrigated crops 47971401 (2010) Dissipation and Aquatic Organism Residue Mon itoring of Aminopyralid in

Small Ponds: Protocol. Project Number: 101046. Unpu blished study prepared by Dow AgroSciences, LLC. 12 p. 48939201 Moore, D.; Newcombe, A.; Havens, P. (2012) Dissipat ion of Aminopyralid in

Flowing Water Systems Under Operational Conditions: Final Report. Project Number: 110423. Unpublished study prepared by Agvis e Laboratories, Inc., Dow AgroSciences LLC, ARCADIS U.S., Inc. and Covance La boratories, Inc. 369p.

### Page 38 of 63

MRID Citation Reference 48939202 Newcombe, A.; Negley, T.; Havens, P. (2012) Dissipa tion and Aquatic Organism

Residue Monitoring of Aminopyralid in Small Ponds: Final Report. Project Number: 101046. Unpublished study prepared by Agvise Labora tories, Inc., ARCADIS U.S., Inc. and Dow AgroSciences, LLC. 376p. 850.7100 Data reporting for environmental che mistry methods 47572602 Wendelburg, B. (2008) Validation Report for Methods GRM 07.07 - Determination

of Residues of Aminopyralid in Agricultural Commodi ties by Liquid Chromatography with Tandem Mass Spectrometric Detec tion, GRM 07.08 - Determination of Residues of Aminopyralid in Bovine and Poultry Tissues, Milk, and Eggs by Liquid Chromatography with Tandem Mass Spectrometric Detection, GRM 07.09 - Determination of Residues of Aminopyral id in Soil by Liquid Chromatography with Tandem Mass Spectrometric Detec tion, and GRM 07.10 - Determination of Residues of Aminopyralid in Drinki ng Water, Ground Water, and Surface Water by Liquid Chromatography with Tandem Mass Spectrometric Detection. Project Number: 071121. Unpublished stud y prepared by Dow AgroSciences, LLC. 207 p. Non-Guideline Study 46235600 Dow AgroSciences LLC (2004) Submission of Residue a nd Toxicity Data in

Support of the Applications for Registration of Ami nopyralid Technical and GF-871 and the Petition for Tolerance of Aminopyralid on G rass Forage, Grass Hay, Wheat Commodities, Milk, Cattle Meat and Meat By-Products . Transmittal of 37 of 108 Studies. 46235601 Hastings, M. (2003) Method Validation Report for th e Determination of Residues of

Aminopyralid in Water by Liquid Chromatography with Tandem Mass Spectrometry Detection Using Dow AgroSciences Method GRM 01.32. Project Number: 011159. Unpublished study prepared by Dow AgroSciences LLC. 48 p. 46235602 Lindsey, A. (2004) Method Validation Report for the Determination of Residues of

Aminopyralid in Soil by Liquid Chromatography with Tandem Mass Spectrometry Detection Using Dow AgroSciences Method GRM 02.34. Project Number: 021295. Unpublished study prepared by Dow Agrosciences LLC. 56 p. 46235700 Dow AgroSciences LLC (2004) Submission of Product C hemistry, Residue and

Environmental Fate Data in Support of the Applicati ons for Registration of Aminopyralid Technical and GF-871 and the Petition for Tolerance of Aminopyralid on Grass Forage, Grass Hay, Wheat Commodities, Milk , Cattle Meat and Meat ByProducts. Transmittal of 35 of 108 Studies. 46235733 Ward, T.; Boeri, R. (2001) XDE-750: 14 Day Soil Exp osure Acute Toxicity to the

Earthworm, Eisenia foetida. Project Number: 2219/DO , 011049. Unpublished study prepared by T.R. Wilbury Laboratories, Inc. 34 p. 46235800 Dow AgroSciences, LLC (2004) Submission of Toxicity , Fate, Risk, and Exposure

Data in Support of the Applications for Registratio n of Aminopyralid Technical and GF-871 and the Petition for Tolerance of Aminopyral id on Grass Forage, Grass Hay, Wheat Commodities, Milk, Cattle Meat and Meat By-Pr oducts. Transmittal of Studies 36 of 109 Studies. 46235834 Havens, P. (2004) Spray Drift Assessment for Terres trial and Aquatic Non-Target

Plants from the Use of Aminopyralid in Canada. Proj ect Number: GH/C/5708. Unpublished study prepared by Dow AgroSciences LLC. 28 p. 46235835 Nelson, J.; Jachetta, J.; Halstvedt, M.; et. al. (2 004) Public Interest Document for

Aminopyralid . Project Number: PID/DOW03JN01. Unpub lished study prepared by ABG, Inc. 144 p.

### Page 39 of 63

MRID Citation Reference 46259601 Jachetta, J.; Havens, P.; Dybowski, J. et. al. (200 4) Reduced-Risk Pesticide

Rationale for Aminopyralid Technical.. Project Numb er: JJ042004. Unpublished study prepared by Dow Agrosciences LLC. 523 p. 46434200 Dow AgroSciences LLC (2004) Submission of Product C hemistry and Toxicity Data

in Support of the Application for Registration of G F-982. Transmittal of 6 Studies. 46434300 Dow AgroSciences, LLC (2004) Submission of Product Chemistry and Toxicity

Data in Support of the Application for Registration of GF-1004. Transmittal of 8 Studies. 46438900 Dow AgroSciences LLC (2004) Submission of Product C hemistry and Toxicity Data

in Support of the Application for Registration of G F-982. Transmittal of 2 Studies. 46661300 Dow Agrosciences LLC (2005) Submission of Product C hemistry and Residue Data

in Support of the Registration of Aminopyralid Tech nical and Milestone. Transmittal of 2 Studies. 46729000 Dow Agroscience LLC (2006) Submission of Residue Da ta in Support of the

Registration of Aminopyralid Technical. Transmittal of 1 Study. 46729600 Dow AgroSciences LLC (2006) Submission of Residue D ata in Support of the

Amended Registration of Aminopyralid Technical. Tra nsmittal of 3 Studies. 46942400 Dow AgroSciences LLC (2006) Submission of Product C hemistry and Toxicity Data

in Support of the Application for Registration of G F-1883. Transmittal of 14 Studies.

Ecological Effects

71-1 Avian Single Dose Oral Toxicity 46235808 Gallagher, S.; Grimes, J.; Beavers, J. (2001) XDE-7 50: An Acute Oral Toxicity

Study with the Northern Bobwhite. Project Number: 3 79/106, 011046. Unpublished study prepared by Wildlife Internationa l, Ltd. 33 p. 46235809 Gallagher, S.; Grimes, J.; Beavers, J. (2003) XDE-7 50 Technical: An Acute Oral

Toxicity Study with the Northern Bobwhite. Project Number: 379/130, 031112. Unpublished study prepared by Wildlife Internationa l, Ltd. 34 p. 48939304 Machado, M. (2002) GF-871 - Acute Toxicity to Rainb ow Trout (Oncorhynchus

mykiss) Under Static Conditions. Project Number: 02 1147/OCR, 12550/6238. Unpublished study prepared by Springborn Smithers L aboratories. 48p.

71-2 Avian Dietary Toxicity 46235810 Gallagher, S.; Beavers, J.; Martin, K. (2001) XDE-7 50: A Dietary LC50 Study

with the Northern Bobwhite. Project Number: 379/107 , 011047. Unpublished study prepared by Wildlife International, Ltd. 51 p

. 46235811 Gallagher, S.; Beavers, J.; Martin, K. (2001) XDE-7 50: A Dietary LC50 Study

with the Mallard. Project Number: 379/108, 011048. Unpublished study prepared by Wildlife International, Ltd. 50 p.

71-4 Avian Reproduction 46235812 Mach, J. (2003) Avian Reproduction Study with XDE-7 50 in Northern Bobwhite

(Colinus virginianus): Final Report. Project Number : 011271, 02001. Unpublished study prepared by Genesis Laboratories, Inc. 122 p.

### Page 40 of 63

46235813 Mach, J. (2003) Avian Reproduction Study with XDE-7 50 in Mallards (Anas

platyrhynchos): Amended Final Report. Project Numbe r: 011272, 02002. Unpublished study prepared by Genesis Laboratories, Inc. 124 p.

72-1 Acute Toxicity to Freshwater Fish 46235814 Marino, T.; McClymont, E.; Yaroch, A.; et. al. (200 1) XDE-750 Herbicide: An

Acute Toxicity Study with the Rainbow Trout, Oncorh ynchus mykiss Walbaum. Project Number: 011078. Unpublished study prepared by The Dow Chemical Co. 36 p. 46235815 Machado, M. (2003) XDE-750 - Acute Toxicity to Blue gill Sunfish (Lepomis

macrochirus) Under Static Conditions. Project Numbe r: 12550/6162, 011225. Unpublished study prepared by Springborn Laboratori es Inc. 47 p. 46235816 Henry, K.; McClymont, E.; Yaroch, A.; et. al. (2003 ) XDE-750: 96-h Acute

Toxicity to Larval Amphibians Using the Northern Le opard Frog, Rana pipiens, as a Biological Model. Project Number: 031030. Unpu blished study prepared by The Dow Chemical Co. 34 p.

72-2 Acute Toxicity to Freshwater Invertebrat es 46235817 Marino, T.; Hales, C.; McClymont, E.; et. al. (2001 ) XDE-750 Herbicide: An

Acute Toxicity Study with the Daphnid, Daphnia magn a Straus. Project Number: 011079. Unpublished study prepared by The Dow Chemi cal Co. 35 p. 48939301 Machado, M. (2002) GF-871 - Acute Toxicity to Daphn ids (Daphnia magna)

Under Static Conditions. Project Number: 021146/OCR , 12550/6237. Unpublished study prepared by Springborn Smithers L aboratories. 47p.

72-3 Acute Toxicity to Estuarine/Marine Organ isms 46235818 Cafarella, M. (2002) XDE-750 - Acute Toxicity to Ea stern Oysters (Crassostrea

virginica) Under Flow-Through Conditions. Project N umber: 12550/6189, 011268. Unpublished study prepared by Springborn La boratories Inc. 53 p. 46235819 Machado, M. (2002) XDE-750 - Acute Toxicity to Mysi ds (Americamysis bahia)

Under Static Conditions. Project Number: 12550/6190 , 011269. Unpublished study prepared by Springborn Laboratories Inc. 46 p

. 46235820 Machado, M. (2002) XDE-750 - Acute Toxicity to Shee pshead Minnow

(Cyprinodon variegatus) Under Static Acute Conditio ns. Project Number: 12550/6191, 011270. Unpublished study prepared by S pringborn Laboratories Inc. 47 p.

72-4 Fish Early Life Stage/Aquatic Invertebra te Life Cycle Study 46235822 Henry, K.; Marino, T.; Staley, J.; et. al. (2003) X DE-750: 21-Day Chronic

Toxicity with the Daphnid, Daphnia magna Straus. Pr oject Number: 021085. Unpublished study prepared by The Dow Chemical Co. 51 p.

82-1 Subchronic Oral Toxicity: 90-Day Study 46235620 Stebbins, K.; Baker, P. (2000) XR-750: 4-Week Dieta ry Toxicity Study in Beagle Dogs. Project Number: 001030. Unpublished study pre pared by The Dow Chemical Co. 141 p. 122-1 Seed Germination/Seedline Emergence and Vegetable Vigor

### Page 41 of 63

46235824 Aufderheide, J. (2004) Effect of GF-871 on Seedling Emergence and Growth of

Selected Non-Target Terrestrial Plants (Tier II). P roject Number: 48322, 030066. Unpublished study prepared by Analytical Bio-Chemis try Labs., Inc. 89 p. 46235825 Aufderheide, J. (2004) Effect of GF-871 on Vegetati ve Vigor of Selected NonTarget Terrestrial Plants (Tier II). Project Number : 48323, 030066. Unpublished study prepared by Analytical Bio-Chemistry Labs, In c. 90 p.

122-2 Aquatic plant growth 46235826 Hoberg, J. (2003) XDE-750 - Toxicity to Duckweed, L emna gibba. Project

Number: 12550/6160, 011223. Unpublished study prepa red by Springborn Laboratories Inc. 64 p. 46235827 Hoberg, J. (2002) XDE-750 - Acute Toxicity to the F reshwater Diatom (Navicula

pelliculosa). Project Number: 12550/6198, 011278. U npublished study prepared by Springborn Laboratories Inc. 61 p. 46235828 Hoberg, J. (2002) XDE-750 - Growth Inhibition Test with Marine Diatom

(Skeletonema costatum). Project Number: 12550/6200, 011280. Unpublished study prepared by Springborn Laboratories Inc. 62 p

. 46235829 Hoberg, J. (2002) XDE-750 - Growth Inhibition Test with Freshwater Blue-green

Alga (Anabaena flos-aquae). Project Number: 12550/6 199, 011279. Unpublished study prepared by Springborn Laboratories Inc. 57 p

. 48939403 Wemhoner, U. (2006) GF-1883 - Growth Inhibition Tes t with Freshwater Diatom

(Navicula pelliculosa). Project Number: 060393/OCR, 1072/010/440. Unpublished study prepared by Springborn Smithers L aboratories (Europe). 71p.

123-1 Seed germination/seedling emergence and vegetative vigor 46235824 Aufderheide, J. (2004) Effect of GF-871 on Seedling Emergence and Growth of

Selected Non-Target Terrestrial Plants (Tier II). P roject Number: 48322, 030066. Unpublished study prepared by Analytical Bio-Chemis try Labs., Inc. 89 p. 46235825 Aufderheide, J. (2004) Effect of GF-871 on Vegetati ve Vigor of Selected NonTarget Terrestrial Plants (Tier II). Project Number : 48323, 030066. Unpublished study prepared by Analytical Bio-Chemistry Labs, In c. 90 p.

123-2 Aquatic plant growth 46235826 Hoberg, J. (2003) XDE-750 - Toxicity to Duckweed, L emna gibba. Project

Number: 12550/6160, 011223. Unpublished study prepa red by Springborn Laboratories Inc. 64 p. 46235827 Hoberg, J. (2002) XDE-750 - Acute Toxicity to the F reshwater Diatom (Navicula

pelliculosa). Project Number: 12550/6198, 011278. U npublished study prepared by Springborn Laboratories Inc. 61 p. 46235828 Hoberg, J. (2002) XDE-750 - Growth Inhibition Test with Marine Diatom

(Skeletonema costatum). Project Number: 12550/6200, 011280. Unpublished study prepared by Springborn Laboratories Inc. 62 p

. 46235829 Hoberg, J. (2002) XDE-750 - Growth Inhibition Test with Freshwater Blue-green

Alga (Anabaena flos-aquae). Project Number: 12550/6 199, 011279. Unpublished study prepared by Springborn Laboratories Inc. 57 p

. 46235830 Hoberg, J. (2003) XDE-750 -Toxicity to the Freshwat er Green Alga,

Pseudokirchneriella subcapitata. Project Number: 12 550/6161, 011222. Unpublished study prepared by Springborn Laboratori es Inc. 66 p.

### Page 42 of 63

48939403 Wemhoner, U. (2006) GF-1883 - Growth Inhibition Tes t with Freshwater Diatom

(Navicula pelliculosa). Project Number: 060393/OCR, 1072/010/440. Unpublished study prepared by Springborn Smithers L aboratories (Europe). 71p.

141-1 Honey bee acute contact 46235831 Aufderheide, J. (2001) XDE-750: Acute Contact Toxic ity Test with the

Honeybee, Apis mellifera. Project Number: 46595, 01 1044. Unpublished study prepared by Analytical Bio-Chemistry Labs, Inc. 17 p. 850.1010 Aquatic invertebrate acute toxicity, test, freshwater daphnids 48939401 Wemhoner, U. (2006) GF-1883 - Acute Toxicity to Wat er Fleas (Daphnia

magna) Under Flow-Through Conditions. Project Numbe r: 060395/OCR, 1072/010/110. Unpublished study prepared by Springb orn Smithers Laboratories (Europe). 57p. 48939501 Rebstock, M. (2011) GF-2633: Acute Toxicity to the Water Flea, Daphnia

magna, Determined Under Static Test Conditions. Pro ject Number: 110056/OCR, 66953. Unpublished study prepared by ABC Laboratori es, Inc. 49p. 850.1025 Oyster acute toxicity test (shell de position) 46235818 Cafarella, M. (2002) XDE-750 - Acute Toxicity to Ea stern Oysters (Crassostrea

virginica) Under Flow-Through Conditions. Project N umber: 12550/6189, 011268. Unpublished study prepared by Springborn La boratories Inc. 53 p. 48939302 Gerke, A. (2012) GF-871: Effect on New Shell Growth of the Eastern Oyster

(Crassostrea virginica). Project Number: 110062/OCR , 66960. Unpublished study prepared by ABC Laboratories, Inc. 58p. 48939502 Gerke, A. (2011) GF-2633: Effect on New Shell Growt h of the Eastern Oyster

(Crassostrea virginica). Project Number: 110059/OCR , 66957. Unpublished study prepared by ABC Laboratories, Inc. 59p.

850.1035 Mysid acute toxicity test 46235819 Machado, M. (2002) XDE-750 - Acute Toxicity to Mysi ds (Americamysis bahia)

Under Static Conditions. Project Number: 12550/6190 , 011269. Unpublished study prepared by Springborn Laboratories Inc. 46 p

. 48939303 Bergfield, A. (2011) GF-871: Acute Toxicity to the Mysid Shrimp,

Americamysis bahia, Determined Under the Static-Ren ewal Test Conditions. Project Number: 110061/OCR, 66959. Unpublished stud y prepared by ABC Laboratories, Inc. 49p. 48939503 Bergfield, A. (2011) GF-2633: Acute Toxicity to the Mysid Shrimp,

Americamysis bahia, Determined Under the Static-Ren ewal Test Conditions. Project Number: 110058/OCR, 66956. Unpublished stud y prepared by ABC Laboratories, Inc. 50p.

850.1075 Fish acute toxicity test, freshwater and marine 46235820 Machado, M. (2002) XDE-750 - Acute Toxicity to Shee pshead Minnow

(Cyprinodon variegatus) Under Static Acute Conditio ns. Project Number: 12550/6191, 011270. Unpublished study prepared by S pringborn Laboratories Inc. 47 p.

850.1350 Mysid chronic toxicity test

### Page 43 of 63

48939305 Dinehart, S. (2011) GF-871: Acute Toxicity to the S heepshead Minnow,

Cyprinodon variegatus, Determined Under Static-Rene wal Conditions. Project Number: 110060/OCR, 66958. Unpublished study prepar ed by ABC Laboratories, Inc. 51p. 48939402 Wemhoner, U. (2006) GF-1883 - Acute Toxicity to Rai nbow Trout

(Oncorhynchus mykiss) Under Flow-Through Conditions . Project Number: 060394/OCR, 1072/010/108. Unpublished study prepare d by Springborn Smithers Laboratories (Europe). 55p. 48939504 Gerke, A. (2011) GF-2633: Acute Toxicity to the Blu egill Sunfish, Lepomis

macrochirus, Determined Under Static-Renewal Condit ions. Project Number: 110055/OCR, 66954. Unpublished study prepared by AB C Laboratories, Inc. 49p. 48939505 Dinehart, S. (2011) GF-2633: Acute Toxicity to the Sheepshead Minnow,

Cyprinodon variegatus, Determined Under Static-Rene wal Conditions. Project Number: 110057/OCR, 66955. Unpublished study prepar ed by ABC Laboratories, Inc. 52p. 48939203 Hicks, S. (2011) Aminopyralid: Life-Cycle Toxicity Test of the Saltwater Mysid,

Americamysis bahia, Conducted under Flow-Through Co nditions. Project Number: 101583, 66018. Unpublished study prepared b y ABC Laboratories, Inc. 84p.

850.1400 Fish early-life stage toxicity test 48939204 Hicks, S. (2011) Aminopyralid: Early Life-Stage Tes t with the Sheepshead

Minnow, Cyprinodon variegatus, Under Flow-Through C onditions. Project Number: 101582, 66015. Unpublished study prepared b y ABC Laboratories, Inc. 79p.

850.2100 Avian acute oral toxicity test 46235809 Gallagher, S.; Grimes, J.; Beavers, J. (2003) XDE-7 50 Technical: An Acute Oral

Toxicity Study with the Northern Bobwhite. Project Number: 379/130, 031112. Unpublished study prepared by Wildlife Internationa l, Ltd. 34 p.

850.2300 Avian reproduction test 47109901 Temple, D.; Martin, K.; Beavers, J.; et al. (2007) XDE-750 A Reproduction

Study with the Northern Bobwhite: Final Report. Pro ject Number: 379/176, 60091. Unpublished study prepared by Wildlife Inter national, Ltd. 157 p. 850.4225 Seedling emergence, Tier II 46235824 Aufderheide, J. (2004) Effect of GF-871 on Seedling Emergence and Growth of

Selected Non-Target Terrestrial Plants (Tier II). P roject Number: 48322, 030066. Unpublished study prepared by Analytical Bio-Chemis try Labs., Inc. 89 p. 850.4250 Vegetative vigor, Tier II 46235825 Aufderheide, J. (2004) Effect of GF-871 on Vegetati ve Vigor of Selected NonTarget Terrestrial Plants (Tier II). Project Number : 48323, 030066. Unpublished study prepared by Analytical Bio-Chemistry Labs, In c. 90 p.

850.5400 Algal toxicity, Tiers 1 and II

### Page 44 of 63

47109902 Hancock, G.; Arnold, B.; Najar, J.; et al. (2007) A minopyralid: Growth Inhibition

Test with the Blue-Green Alga, Anabaena flos-aquae. Project Number: 061150. Unpublished study prepared by DOW Chemical Corp. 46 p.

Non-Guideline Study 46235733 Ward, T.; Boeri, R. (2001) XDE-750: 14 Day Soil Exp osure Acute Toxicity to the

Earthworm, Eisenia foetida. Project Number: 2219/DO , 011049. Unpublished study prepared by T.R. Wilbury Laboratories, Inc. 3 4 p. 46235821 Marino, T.; McClymont, E.; Yaroch, A.; et. al. (200 3) Revised Report for XDE750: Toxicity to the Early Life Stages of the Fathe ad Minnow, Pimephales promelas Rafinesque. Project Number: 021029. Unpubl ished study prepared by The Dow Chemical Co. 55 p. 46235823 Putt, A. (2002) XDE-750 - The Full Life-Cycle Toxic ity to Midge (Chironomus

riparius) Under Static Conditions. Project Number: 12550/6195, 011277. Unpublished study prepared by Springborn Laboratori es Inc. 88 p. 46235832 Aufderheide, J. (2001) XDE-750: Acute Oral Toxicity Test with the Honeybee

(Apis mellifera). Project Number: 46596, 011045. Un published study prepared by Analytical Bio-Chemistry Labs, Inc. 20 p. 46235833 Domoradzki, J.; Rick, D.; Clark, A. (2004) XDE-750, Triisopropanolamine Salt:

Dissociation and Metabolism in Male Fischer 344 Rat s. Project Number: 031129, 2004/8. Unpublished study prepared by The Dow Chemi cal Co. 57 p.

### Page 45 of 63



### Appendix A. Summary of registered products contain ing aminopyralid and its salts.

Table A1. Registered products containing the TIPA salt of aminopyralid

Registration # Name Status Percent Active Ingredient Active Ingredient
% Active Ingredient

62719-519 MILESTONE Conditionally Registered (10-Aug-2005) 40.6 Triisopropanolamine salt of aminopyralid

62719-524 FOREFRONT

R&P Conditionally Registered

(22-Nov-2005) 51.06 2,4-D, triisopropanolamine salt

6.58 Triisopropanolamine salt of

aminopyralid

62719-537 MILESTONE VM Conditionally Registered (24-Oct-2005) 40.6 Triisopropanolamine salt of aminopyralid

62719-572 MILESTONE VM

PLUS Conditionally Registered

(19-Apr-2007) 2.22 Triisopropanolamine salt of aminopyralid

16.22 Triclopyr, triethylamine salt

62719-579 GF-2003 Conditionally Registered (03-Oct-2007) 1.5 Triisopropanolamine salt of aminopyralid

51.6 2,4-D, triisopropanolamine

salt

62719-587 GRAZONNEXT Conditionally Registered (12-Feb-2008) 6.58 Triisopropanolamine salt of aminopyralid

51.06 2,4-D, triisopropanolamine

salt

62719-628 GrazonNext HL Registered (10-Mar-2011) 8.24 Triisopropanolamine salt of aminopyralid
41.26 2,4-D, dimethylamine salt

62719-629 PASTURALL HL Registered (10-Mar-2011) 44.45 2,4-D, triisopropanolamine salt

2 Triisopropanolamine salt of

aminopyralid

62719-630 FOREFRONT HL Registered (10-Mar-2011) 8.24 Triisopropanolamine salt of aminopyralid

41.26 2,4-D, dimethylamine salt

AL090003 MILESTONE VM Registered (06-Jul-2009) 40.6 Triisopropanolamine salt of aminopyralid
AL120004 MILESTONE Registered (06-Aug-2012) 40.6 Triisopropanolamine salt of aminopyralid

AL120007 MILESTONE Registered (17-Jan-2013) 40.6 Triisopropanolamine salt of aminopyralid

AR100004 MILESTONE VM Registered (14-Apr-2011) 40.6 Triisopropanolamine salt of aminopyralid

CA130004 MILESTONE Registered (08-Apr-2013) 40.6 Triisopropanolamine salt of aminopyralid

FL110008 MILESTONE VM Under Review (17-Nov2011) 40.6 Triisopropanolamine salt of aminopyralid

### Page 46 of 63 Registration # Name Status Percent Active Ingredient Active Ingredient
% Active Ingredient
FL120002 MILESTONE Registered (31-Jul-2012) 40.6 Triisopropanolamine salt of aminopyralid
GA090005 MILESTONE VM Registered (31-Mar-2009) 40.6 Triisopropanolamine salt of aminopyralid
GA120003 MILESTONE Registered (31-Jul-2012) 40.6 Triisopropanolamine salt of aminopyralid
GA120007 MILESTONE Registered (13-Dec-2012) 40.6 Triisopropanolamine salt of aminopyralid
HI120003 MILESTONE Registered (10-Oct-2012) 40.6 Triisopropanolamine salt of aminopyralid
LA120004 MILESTONE Registered (03-Aug-2012) 40.6 Triisopropanolamine salt of aminopyralid
LA120020 MILESTONE Registered (05-Mar-2013) 40.6 Triisopropanolamine salt of aminopyralid
MN110004 MILESTONE VM Registered (13-May-2011) 40.6 Triisopropanolamine salt of aminopyralid
MN120005 MILESTONE Registered (31-Jul-2012) 40.6 Triisopropanolamine salt of aminopyralid
MS090008 MILESTONE VM Registered (31-Mar-2009) 40.6 Triisopropanolamine salt of aminopyralid
MS120008 MILESTONE Registered (06-Aug-2012) 40.6 Triisopropanolamine salt of aminopyralid
MS120012 MILESTONE Registered (24-Oct-2012) 40.6 Triisopropanolamine salt of aminopyralid

NC090005 MILESTONE VM Under Review (17-Nov2009) 40.6 Triisopropanolamine salt of aminopyralid
NC100004 MILESTONE VM Registered (14-Apr-2011) 40.6 Triisopropanolamine salt of aminopyralid
NC120003 MILESTONE Registered (31-Jul-2012) 40.6 Triisopropanolamine salt of aminopyralid
NC120010 MILESTONE Registered (01-Nov-2012) 40.6 Triisopropanolamine salt of aminopyralid
SC090004 MILESTONE VM Registered (16-Apr-2009) 40.6 Triisopropanolamine salt of aminopyralid
SC110001 MILESTONE VM Registered (05-May-2011) 40.6 Triisopropanolamine salt of aminopyralid
TN130002 MILESTONE Registered (30-Apr-2013) 40.6 Triisopropanolamine salt of aminopyralid
TX110002 MILESTONE VM Registered (14-Apr-2011) 40.6 Triisopropanolamine salt of aminopyralid
TX120005 MILESTONE Registered (06-Aug-2012) 40.6 Triisopropanolamine salt of aminopyralid
TX120014 MILESTONE Registered (13-Dec-2012) 40.6 Triisopropanolamine salt of aminopyralid
VA100004 MILESTONE VM Registered (14-Apr-2011) 40.6 Triisopropanolamine salt of aminopyralid

VA110003 MILESTONE VM Under Review (03-May2011) 40.6 Triisopropanolamine salt of aminopyralid

### Page 47 of 63 Registration # Name Status Percent Active Ingredient Active Ingredient
% Active Ingredient
VA120005 MILESTONE Registered (15-Oct-2012) 40.6 Triisopropanolamine salt of aminopyralid
VA120006 MILESTONE Registered (18-Oct-2012) 40.6 Triisopropanolamine salt of aminopyralid

Table A2. Registered products containing the potas sium salt of aminopyralid

Registration # Name Status Percent Active Ingredient Active Ingredient
% %

62719-576 GF-1118 Conditionally Registered (10-Jul-2007) 88.8 Aminopyralid potassium salt

62719-597 CHAPARRAL Conditionally Registered (23-Jul-2008) 9.45 Metsulfuron

62.13 Aminopyralid potassium salt

62719-617 Opensight WG Registered (03-Aug-2010) 9.45 Metsulfuron 62.13 Aminopyralid potassium salt

62719-645 GF-2791 Registered (15-Feb-2012) 30.82 Clopyralid, monoethanolamine salt 6.02 Aminopyralid potassium salt

ID090018 OPENSIGHT Registered (05-Mar-2010) 62.13 Aminopyralid potassium salt

9.45 Metsulfuron
OR110017 OPENSIGHT Registered (10-Jan-2012) 62.13 Aminopyralid potassium salt
9.45 Metsulfuron
WA110011 OPENSIGHT Registered (10-Jan-2012) 62.13 Aminopyralid potassium salt
9.45 Metsulfuron

Table A2. Registered products containing aminopyra lid
Registration # Name Status Percent Active Ingredient
% Active Ingredient

62719-518 AMINOPYRALID

TECHNICAL Conditionally Registered

(10-Aug-2005) 95.3 Aminopyralid

62719-525 CLEANWAVE Conditionally Registered (02-Dec-2005) 20.22 Fluroxypyr 1-methylheptyl
ester 1.92 Aminopyralid
FL070003 CLEANWAVE Registered (13-Sep-2007) 20.22 Fluroxypyr 1-methylheptyl
ester FL070003 CLEANWAVE Registered (13-Sep-2007) 1.92 Ami nopyralid

### Page 48 of 63



### Appendix B. Ecological Model Results

A. Screening Imbibition Model (SIP; version 1.0) Table 1. Inputs Parameter Value Chemical name Aminopyralid Solubility (in water at 25 o C; mg/L) 212000

Mammalian LD 50 (mg/kg-bw) 5000 Mammalian test species laboratory rat

Mammalian NOAEL (mg/kg-bw) 1000 Mammalian test species laboratory rat

Avian LD 50 (mg/kg-bw) 2250 Avian test species mallard duck Mineau scaling factor 1.15

Mallard NOAEC (mg/kg-diet) 2623 Bobwhite quail NOAEC (mg/kg-diet) 2500

Table 2. Mammalian Results Parameter Acute Chronic Upper bound exposure (mg/kg-bw) 36464.0000 36464.0000 Adjusted toxicity value (mg/kg-bw) 3845.8028 769.1606 Ratio of exposure to toxicity 9.4815 47.4075

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) 171720.0000 171720.0000 Adjusted toxicity value (mg/kg-bw) 1168.2572 130.1338 Ratio of exposure to acute toxicity 146.9882 1319.5654

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. Ther efore, when aggregated with other routes ( i.e ., diet, inhalation, dermal), pesticide exposure th rough drinking water may contribute to a total exposure that has potenti al for effects to non-target animals.

### Page 49 of 63



### EFED Screening Tool for Inhalation Risk (STIR, vers ion 1.0)
This tool is designed to provide the risk assessor with a rapid method for determining the potential significance of the inhal ation exposure route to birds and mammals in a risk assessment.


# Input

Application and Chemical Information
Enter Chemical Name Aminopyralid Enter Chemical Use 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) 207 Enter Chemical Vapor Pressure (mmHg) 1.94E-10 Enter Application Rate (lb a.i./acre) 0.22

Toxicity Properties
Bird Enter Lowest Bird Oral LD 50 (mg/kg bw) 2250 Enter Mineau Scaling Factor 1.15 Enter Tested Bird Weight (kg) 0.178 Mammal Enter Lowest Rat Oral LD 50 (mg/kg bw) 1000 Enter Lowest Rat Inhalation LC 50 (mg/L) 5.5 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 ) 2.16E-06 Maximum 1-hour Vapor Inhalation Dose (mg/kg) 2.72E-07 Adjusted Inhalation LD 50 6.90E+01

Ratio of Vapor Dose to Adjusted Inhalation LD 50 3.94E-09 Exposure not Likely Significant Maximum Post-treatment Spray Inhalation Dose (mg/kg ) 2.32E-02

Ratio of Droplet Inhalation Dose to Adjusted Inhala tion LD 50 3.37E-04 Exposure not Likely Significant



### Results Mammalian (0.015 kg ) Maximum Vapor Concentration in Air at Saturation 2.16E-06

### Page 50 of 63

(mg/m 3 ) Maximum 1-hour Vapor Inhalation Dose (mg/kg) 3.41E-07 Adjusted Inhalation LD 50 3.27E+02

Ratio of Vapor Dose to Adjusted Inhalation LD 50 1.04E-09 Exposure not Likely Significant Maximum Post-treatment Spray Inhalation Dose (mg/kg ) 2.92E-02

Ratio of Droplet Inhalation Dose to Adjusted Inhala tion LD 50 8.92E-05 Exposure not Likely Significant

### Page 51 of 63

Appendix C. 

### AOPwin output

SMILES : CLc1c(nc(CL)cc1N)C(=O)O CHEM : MOL FOR: C6 H4 CL2 N2 O2 MOL WT : 207.02 ------------------- SUMMARY (AOP v1.92): HYDROXYL R ADICALS (25 deg C) -------- Hydrogen Abstraction = 0.0000 E-12 cm3/mole cule-sec Reaction with N, S and -OH = 0.5200 E-12 cm3/mole cule-sec Addition to Triple Bonds = 0.0000 E-12 cm3/mole cule-sec Addition to Olefinic Bonds = 0.0000 E-12 cm3/mole cule-sec Addition to Aromatic Rings = 1.1446 E-12 cm3/mole cule-sec Addition to Fused Rings = 0.0000 E-12 cm3/mole cule-sec

OVERALL OH Rate Constant = 1.6646 E-12 cm3/mol ecule-sec HALF-LIFE = 6.426 Days (12-hr day; 1.5E6 OH/ cm3) HALF-LIFE = 77.108 Hrs ------------------- SUMMARY (AOP v1.91): OZONE REAC TION (25 deg C) -----------

****** NO OZONE REACTION ESTIMATION ****** (ONLY Olefins and Acetylenes are Est imated)

Experimental Database: NO Structure Matches

### Page 52 of 63

Appendix D. Maximum or maximum mean amount of appl ied radioactivity present as a specified compound in environmental fate studies su bmitted on Aminopyralid

Table D1. Maximum or maximum mean amount of applie d radioactivity present as a specified compound in environmental fate studies submitted on Aminopyralid. 1,2

Compound Study Type Max %AR (Sampling Interval) Final %AR

(Sampling Interval) Comment MRID

Parent Hydrolysis 99.8 (0d) 98.6 (32d) pH 5 46235726 100 (0d) 101 (31d) pH 7 98 (0d) 99 (31d) pH 9 Aqueous Photolysis 92.4 (1h) ND (360h) pH 5 46235727
Soil Photolysis 105 (0d) 75 (44d) Silt loam 4623572 8

Aerobic Soil 99.7 (0d) 3.8 (365d) Holdredge, 60 g/ha 46235729

102 (0d) 3.7 (365d) Holdredge, 120 96 (0d) 2.4 (123d) Thessaloniki

47911201 92 (0d) 52 (123d) Cuckney 92 (0d) 4.2 (92d) Charentilly 93 (0d) 34 (123d) Parabraun, 20 o C 98 (0d) 101 (122d) Parabraun, sterile 97 (0d) 78 (123d) Parabraun, 10 o C 97 (0d) 46 (123d) Parabraun, 30 o C 94 (0d) 46 (126d) Arkansas 47925801 92 (0d) 42 (126d) Nebraska 96 (0d) 6.5 (59d) Florida

Aerobic Aquatic 96 (0d) 91 (101d) French sediment 46235731

98 (0d) 83 (101d) Italian sediment 98 (0d) 90 (101d) US sediment Anaerobic Aquatic 98 (0d) 98 (363d) ND sediment 46235730

100 (0d) 93 (120d) Cuckney soil

Terrestrial Field Dissipation 144.2 ng/g (0d) 2.4 (183d) Mississippi 46235734

107.2 ng/g (0d) ND (182d) California
110.6 g/ha (0d) 3 g/ha

(121d) New Brunswick

46235735 130.3 g/ha (0d) 3.5 g/ha

(368 d) Ontario

165.4 g/ha (0d) 9.4 g/ha

(121d) Manitoba

151.5 g/ha (0d) 2.8 g/ha

(123d) Saskatchewan
113.3 g/ha (0d) ND (372d) Montana
97.0 g/ha (0d) 6.0 g/ha

(455d) Alberta

Aquatic Field Dissipation 32.9 μg/L (0d) ND (120d) Oregon, water

48939201

14.6 μg/kg (0d) ND (120d) Oregon, sediment
32.3 μg/L 0.0181

(120d) Florida, water
1.13 μg/kg ND (120d) Florida, sediment
198 μg/L (0d) 0.28 μg/L

(120d) Texas, pond water 48939202 4.4 μg/kg (14d) 1.6 μg/kg

(90d) Texas pond

sediment

### Page 53 of 63

Compound Study Type Max %AR (Sampling Interval) Final %AR

(Sampling Interval) Comment MRID

6.8 μg/kg (7d) -- Texas pond crayfish 114 μg/L (0d) 0.27 μg/L

(120d) Indiana pond wter

30.1 μg/kg (7d) -- Indiana pond sunfish
3.4 μg/kg (21d) 2.0 μg/kg

(90d) Indiana pond

sediment 8 min (6 components all <10%AR at 10hrs) 3 Aqueous

Photolysis 69 (288h) 67 (360h) pH 5 46235727

11.5 min 3 Aqueous

Photolysis 2.9 (288h) 2.7 (360h) pH 5 46235727

16 min 3 Aqueous

Photolysis 3.3 (48h) ND pH 5 46235727

Unidentified Aqueous

Photolysis 8.7 (8h) 1.5 (360h) pH 5 46235727

Soil Photolysis 6.9 (44d) 6.9 (44d) Silt loam 46235 728

Anaerobic Aquatic 1 (268d) 0.6 (363d) ND sediment 46235730

0.8 (59d) 0 (120d) Cuckney soil

CO 2 Hydrolysis NA NA pH 5,7,9 46235726

Aqueous Photolysis 29 (360h) 29 (360h) pH 5 46235727
Soil Photolysis 3.4 (44d) 3.4 (44d) Silt loam 46235 728

Aerobic Soil 75 (274d) 70 (365d) Holdredge, 60 g/ha 46235729

76 (190d) 70 (365d) Holdredge, 120 g/ha 68 (92d) 65 (123d) Thessaloniki

47911201 29 (123d) 29 (123d) Cuckney 69 (92d) 69 (92d) Charentilly 41 (123d) 41 (123d) Parabraun, 20 o C 3.2 (122d) 3.25 (122d) Parabraun, sterile 11 (123d) 11 (123d) Parabraun, 10 o C 36 (123d) 36 (123d) Parabraun, 30 o C 34 (126d) 34 (126d) Arkansas 47925801 40 (126d) 40 (126d) Nebraska 61 (59d) 61 (59d) Florida

Aerobic Aquatic 2.7 (101d) 2.7 (101d) French sediment 46235731

3.0 (62d) 1.3 (101d) Italian sediment 1.2 (101d) 102 (101d) US sediment Anaeroibic Aquatic 0.7 (268d) 0.6 (363d) ND sediment 46235730

0.4 (120d) 0. (120d) Cuckney soil

Unextracted Residues Soil Photolysis 8.0 (44d) 8.0 (44d) Silt loam 46235 728

Aerobic Soil 13 (63d) 5 (365d) Holdredge, 60 g/ha 46235729

13 (63d) 5 (365d) Holdredge, 120 20 (123d) 20 (123d) Thessaloniki

47911201 9 (123d) 9 (123d) Cuckney 21 (61d) 17 (92d) Charentilly 15 (123d) 15 (123d) Parabraun, 20 o C 2.3 (122d) 2.3 (122d) Parabraun, sterile

### Page 54 of 63

Compound Study Type Max %AR (Sampling Interval) Final %AR

(Sampling Interval) Comment MRID

7.1 (123d) 7.1 (123d) Parabraun, 10 o C 12 (123d) 12 (123d) Parabraun, 30 o C 13 (126d) 13 (126d) Arkansas 47925801 12 (126d) 12 (126d) Nebraska 22 (59d) 22 (59d) Florida
Aerobic Aquatic 3.2 (101d) 3.2 (101d) French sediment 46235731

15 (101d) 15 (101d) Italian sediment 7.0 (101d) 7.0 (101d) US sediment Anaerobic Aquatic 2.4 (181d) 1.2 (363d) ND sediment 46235730

1.3 (30d) 0.7 (120d) Cuckney soil

1 Maximum amounts of organic volatiles were minimal in all studies (<0.1%AR).
2 Many of the metabolism studies had multiple uniden tified minor degradates that were not identified. They were not added together and placed under an un identified compound(s) list as their presence was expected to have little impact on decision making.
3 The identity of these residues were not specified; however, two degradates were shown to be oxamic ac id and malonomic acid. The portion of the oxamic and malonomic acid was not reported. The other degradates are expected to be small polar molecules

.

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### Appendix E. Ecological Incidence Reports

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### Dow herbicide that contaminated Green Mountain Comp ost now effectively banned in the Northeast, Kate Robinson Jun. 10, 2013 http://vtdigger.org/2013/06/10/herbicide-that-conta minated-green-mountain-compostnow-effectively-banned-in-vermont/ (accessed 1/23/2014)

CSWD: Herbicide contamination in compost extends to bagged products. Matt Sutkoski - http://www.burlingtonfreepress.com/apps/pbcs.dll/ar ticle?AID=/20120706/NEWS02/307 060008/&template=artiphone&nclick_check=1 (accessed 1/23/14)