OFFICE OF CHEMICAL SAFETY AND POLLUTION PREVENTION 

### UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
WASHINGTON

, D.C. 20460

August 28, 2014

PC Code: 110902
MEMORANDUM DP Barcode: 419903

SUBJECT: EFED Registration Review Problem Formulation for Diclofop-methyl

FROM: N.E. Federoff, Wildlife Biologist Greg Orrick, Environmental Scientist
Environmental Risk Branch 2
Environmental Fate a nd Effects Division (7507P)

THRU: Brian Anderson, Chief R. David Jones, PhD, Senior Agronomist Christina Wendel, Biologist Jean Holmes, DVM, MPH, RAPL
Environmental Risk Branch 2
Environmental Fate a nd Effects Division (7507P)

TO: Marianne Mannix, Chemical Review Manager Patricia Parrott, Branch Chief Risk Management and Implementation Branch III Pesticide Re-Evaluation Division (7508P)

The Environmental Fate and Effects Division (E FED) has completed the preliminary problem formulation (attached) for the ecological risk, environmental fate, endangered species, and drinking water assessments to be co nducted as part of the registra tion review of diclofop-methyl. The problem formulation describes the preliminary risk hypothesis and the processes that will be used during the completion of drinking water an d ecological risk assessm ents in support of registration review. This document draws on in formation from both open literature and studies submitted by the registrants in response to data re quirements in order to provide an overview of the environmental fate and ecological effects associ ated with the use of diclofop-methyl as well as to outline uncertainties regarding residues and ta xa of concern. This document also identifies
additional studies that would be beneficial to complete an ecol ogical risk assessment. Major findings include:

Studies Needed

 Aerobic aquatic metabolism (835.4300; diclofop-methyl): two systems

 Anaerobic aquatic metabolism (835.4400; diclofop-methyl): one system

### Page 2 of 50 

###  Analytical method in water and associated independent laboratory validation (850.6100; diclofop-methyl and its acid): with an LOQ le ss than 7.5 μg/L (the lowest toxicological level of concern) for the ester and its acid.

 Honeybee toxicity (850.3020 and non-guideline Adult Acute Oral and Larval Toxicity). In keeping with the Agency’s proposed new paradigm for determining potential adverse effects to insect pollinators from conventi onal pesticides (USEPA 2012), two additional studies are being requested in addition to th e acute contact study. An adult acute oral toxicity study (following OECD 213) and a larval oral toxicity study (following OECD 237) are necessary to evaluate the potential fo r diclofop-methyl to adversely affect bees and other pollinators. Also, several of the treated crop areas may be considered attractive to honey bees and this is a systemic chem ical that is transported throughout the plant. Thus, residues may be available to pollinators via pollen and/or nectar. For assessment purposes, EFED will use the mo st current exposure assessment methodology to estimate exposures through pollen and nect ar, thus EFED is not asking for pollen and
nectar residue data at this time.

 Aquatic Plant Toxicity (850.4500 & 850.4550). Aqua tic plant testing is required for any
herbicide that has outdoor non-residential te rrestrial uses that may move off-site by runoff, by drift, or that is applied directly to water. Only one aquatic plant study has been submitted. A study using a non-vascular plant (algae) is needed.

 Estuarine/Marine Fish and Invertebrate Acute Toxicity (850.1025, 850.1035 and 850.1075). No data have been submitted regarding acute toxicity to estuarine/marine fish or invertebrates. Although a pplications are prohibited with in 100 ft of any water bodies, diclofop-methyl is highly acutely toxic to freshwater fish and invertebrates. EFED will
consider the effectiveness of the buffer in reducing risk to aquatic organisms in the preliminary risk assessment. In addition, us e on golf courses can occur near estuarine areas. Acute studies with the sheepshead minnow, mysid and oyster (shell deposition)
are needed.

Major Uncertainties

 The reapplication interval for us es on golf course turf is not stated on the label. In the absence of a stated interval, a 3-day interval will be assumed

 Uncertainty exists for risk to terrestrial insects (honey bees) because no toxicity data have been submitted. Diclofop-methyl is a systemic herbicide and could pose risk to bees.

 Also, only one aquatic plant toxicity study (growth inhibition using duckweed) has been submitted for diclofop-methyl or diclofop acid, as a systemic herbicide toxicity, risk to aquatic plants is presumed in the absence of data.

### Page 3 of 50 

# Table	of	Contents

1. Introduction .................................................................................................................. ........... 4
2. Use Characterization .......................................................................................................... ..... 4
3. Conclusions from Previous Risk Assessments ....................................................................... 6
3.1. Ecological Risk Assessments ........................................................................................... 6
3.2. Drinking Water Exposure Assessments ........................................................................... 7
3.3. Clean Water Act Programs ............................................................................................... 7
3.3.1. Aquatic Life Criteria and Aquatic Life Benchmarks .................................................... 7
3.3.2. Impaired Water Bodies ................................................................................................. 7
4. Environmental Fate and Transport.......................................................................................... 8
4.1. Transformation Products ................................................................................................ 10
5. Receptors...................................................................................................................... ......... 12
5.1. Effects to Aquatic Organisms ........................................................................................ 13
5.2. Effects to Terrestrial Organisms .................................................................................... 14
5.3. Ecological Incidents ....................................................................................................... 15
6. Exposure Pathways of Concern ............................................................................................ 16
7. Analysis Plan ................................................................................................................. ....... 16
7.1. Stressors of Concern....................................................................................................... 16
7.2. Measures of Exposure .................................................................................................... 17
7.3. Measures of Effect ......................................................................................................... 17
8. Endangered Species Assessments ......................................................................................... 17
9. Endocrine Disruptor Screening Program .............................................................................. 18
10. Preliminary Identification of Data Gaps ............................................................................ 19
10.1. Environmental Fate..................................................................................................... 19
10.2. Ecological Effects ....................................................................................................... 20
11. References .................................................................................................................... ...... 25
APPENDIX A: Eco and Fate Bibl iography for Diclofop-methyl ................................................ 26
APPENDIX B: ECOLOGICAL TOXICITY DATA ................................................................... 39 APPENDIX C: Example of SIP INPUT and OUTPUT ............................................................... 47 APPENDIX D: STIR inputs and outputs ...................................................................................... 49

### Page 4 of 50 

# 1. Introduction

EFED evaluated the most recent ecological risk assessments for diclofop-methyl in association with the updated toxicity, exposur e, and usage information to determine if sufficient data are available and if further updates are needed to support registration review. Recent risk assessments include a Reregistration Eligibili ty Decision (RED) in 2000. In addition, EFED considered the latest Agency science policies an d risk assessment metho dologies. The structure of diclofop-methyl, as well as the chemical na mes and other identifiers can be found in the
environmental fate section.

Diclofop-methyl is a restricted-use herbicide, first registered in 1982, for controlling annual grassy weeds in wheat and barley. Diclofop-methyl is a selective systemic herbicide but also has
contact action. It is absorbed primarily by the leaves, with some absorption by the roots in moist soil. It undergoes rapid transforma tion to diclofop, which is transl ocated within the plant. It destroys the cell membrane, prevents the transl ocation of assimilates to the roots, reduces chlorophyll content and inhibits li pid/fatty acids by biosynthesis.

Diclofop-methyl is an acetyl CoA carboxyl ase (ACCase) inhibitor in the aryloxyphenoxypropionate group that includes fe noxaprop-p-ethyl and nine “fop” herbicides (HRAC, 2012). In 1990, target weeds resistant to diclofop and other ACCase inhibitors began to be observed in Oregon (USDA, 1996; Seefeldt et al. , 1996).



# 2. Use Characterization

Diclofop-methyl is registered for use on wheat, barley, and cl osely mowed golf course turf ( Table 1 ). Applications are prohib ited within 100 feet of any water body. The reapplication interval for uses on golf course turf is not stated on the label. In the absence of a stated interval, a 3-day interval will be assumed.

Table 1. Maximum use patterns for current uses of diclofop-methyl

Product Label

(EPA Reg. No.);
Formulation Active
In g redient (%) Use Site Max. Single App. Rate (lbs a.i./A) Max.
Annual App. Rate (lbs a.i./A) App.
Interval (d) Application Type Additional Application
Directions

Hoelon 3EC (264-641); Emulsifiable
Concentrate Diclofopmethyl (34.7% by wt.) Winter wheat, spring wheat, barley 1.0 1.0 Not applicable Aerial or ground Do not apply
within 100 feet of any water body.

Illoxan 3 EC (432-1231);
Emulsifiable
Concentrate Diclofopmethyl (34.7% by wt.) Golf courses (includes greens, tees, fairways, and closely mowed roughs) 1.02 1.53 Not stated Broadcast or spot

treatment Do not apply within 100 feet of any water body.



### Figure 1 depicts a national-level summa ry of the estimated agricultu ral usage of diclofop-methyl in 2011 (USGS, 2014). National agricultural us age of diclofop-methyl peaked in 1996 and declined to relatively low levels over the next 12 years. Note that most of the crops listed in the figure are not currently register ed uses of diclofop-methyl.

### Page 5 of 50 

### Figure 1. Agricultural Usage of Diclofop-methyl in 2011 (USGS, 2014)

### Page 6 of 50 

# 3. Conclusions from Previous Risk Assessments

3.1. Ecological Risk Assessments

The Agency has previously conducted ecological ri sk assessments on diclofop-methyl that serve as a basis for this scoping document, including the Reregistration Eligib ility Decision (RED). The following are conclusions from the previous assessment.

Diclofop-methyl is practically non-toxic to bird s on an acute basis and poses minimal acute risk. Chronic toxicity to birds is uncertain b ecause tests were not conducted at high enough concentrations, but based on the available informati on, chronic risk to birds is not likely to be a primary concern. Toxicity data indicate that dicl ofop-methyl is more toxic to mammals than to birds, both on an acute and chronic basis. Di clofop-methyl is moderate ly toxic to mammals on an acute basis. It does not pose a high acute risk to mammals except in the case of repeated spot applications to turf. Diclofop-methyl does pos e a potential chronic risk to mammals. Risk quotients for chronic risk to mammals are as high as 8.0 for a single applica tion at 1 lb ai/A, and up to 11.0 for repeated spot appl ications. Previous risk asse ssments resulted in RQs above
established levels of concer n (LOC) for threatened and endangered species of mammals.

Diclofop-methyl is highly toxic on an acute basi s to freshwater fish and invertebrates. The primary degradation product, diclofop acid, is only slightly toxic to freshwater fish. Supplemental information also suggests that diclof op-methyl is highly toxic to the eastern oyster. In a freshwater fish life-cycle test, diclofop-methyl affected larval growth at 15 ppb (NOAEC = 7.5 ppb). In a waterflea life-cyc le test, diclofop-methyl a ffected reproduction at 166 ppb (NOAEC = 64 ppb). However, because the environmental fa te characteristics of diclofop-methyl do not favor transport to surface water, environmen tal concentrations are not expected to reach toxic levels. Thus, acute and chr onic risk is minimal to freshw ater fish and invertebrates.

Like most herbicides, diclofop-methyl poses a risk to some terrestrial non-target plants, especially monocots (grasses and sedges). Spray dr ift and runoff poses a high risk to non-target terrestrial plants. The risk assessment for terrestrial plants indicated that risk is low from exposure of foliage to spray drift, but high from exposure of plant root s from a combination of runoff and spray drift. Risk quotients for soil expo sure were 4.67 to 5.00 for plants in dry areas and 9.17 to 12.50 for semi-aquatic areas. Phytotoxici ty data show that diclofop-methyl is selectively toxic to monocotyledonous plants ( i.e. , grasses and sedges), but not very toxic to dicotyledonous plants ( i.e. , broadleaf plants). This is expected since the target plants of this herbicide are grass weeds. If ri sk quotients were based on toxicity to dicotyledonous plants, they
would not exceed the level of concern. The use of diclofop-methyl poses a high risk to nontarget grasses and sedges from exposure in the soil.

Being an herbicide, diclofop-met hyl and its acid were expected to be toxic to aquatic plants.

### Page 7 of 50 

## 3.2. Drinking Water Exposure Assessments

In 1999, a drinking water exposure assessment for diclofop-methyl was co nducted to support the Reregistration Eligibility Decision (RED) (USEPA, 1999). Upper bound exposure estimates were 1.47 μg/L (1-in-10-year peak) and 0.097 μg /L (10-year mean) for surface water and 0.067 μg/L for ground water. 

### Surface and ground water monitoring data were located in STORET for Minnesota and Idaho; all detections were < 0.1 μg/L 

### . A prospective ground water monitoring study also indicated concentrations were <0.1 μg/L, the limit of quantitation.



## 3.3. Clean Water Act Programs

3.3.1. Aquatic Life Criteria and Aquatic Life Benchmarks

The Clean Water Act requires the Agency to publish water quality criteria that accurately reflect the latest scientific knowledge on the kind and ex tent of all identifiable effects on health and welfare that might be expected from the presen ce of pollutants in any body of water, including ground water. While these recommended cr iteria do not, in themselves, impose any requirements, states and authorized tribes can us e them to develop water quality standards. An Aquatic Life Ambient Water Qu ality Criteria document has no t been published for diclofopmethyl (see url: http://www.epa.gov/waterscience/criteria/ ).

The Office of Pesticide Programs (OPP) publishes a quatic life benchmarks for freshwater species based on toxicity values for the most sensitive species from the most recent risk assessments. However, aquatic life benchmarks have not been published for diclofop-methyl or its acid (see
url: http://www.epa.gov/oppefed1/ecorisk_ders/aquatic_life_benchmark.htm#benchmarks ).



## 3.3.2. Impaired Water Bodies

Diclofop-methyl is not identifie d as a cause of impairment fo r any water bodies listed as impaired under section 303(d) of the Clean Water Act, based on information provided at http://iaspub.epa.gov/tmdl_waters10/attains_ nation_cy.cause_detail_303d?p_cause_group_id=88
5

.

No Total Maximum Daily Load (TMDL) criteria have been developed for diclofop-methyl, based on information provided at http://iaspub.epa.gov/tmdl_waters10/attains_ nation.tmdl_pollutant_de tail?p_pollutant_group_id =885&p_pollutant_group_name=PESTICIDES . More information on impaired water bodies and
TMDLs can be found at http://www.epa.gov/owow/tmdl/ . The Agency invites submission of water quality data for this pesticide. To the exte nt possible, data should conform to the quality standards in Appendix A of the OPP Standard Operating Procedur e: Inclusion of Impaired Water Body and Other Water Quality Data in OPP’s Regist ration Review Risk Assessment and Management Process (see: http://www.epa.gov/oppsrrd1/regist ration_review/water_quality_sop.htm ), in order to ensure they can be used quantitatively or qual itatively in pesticide risk assessments.

### Page 8 of 50 

# 4. Environmental Fate and Transport

Diclofop-methyl (CAS no. 51338-27- 3; chemical structure in Table 3 ) is an ester that is rapidly hydrolyzed to its acid by microbial activity. Aerobic and anaerobic biodegradation half-lives range from <1 to 6 days depending on pH and othe r conditions. Diclofop- methyl is stable to abiotic hydrolysis at pH 5, but hydrolyzes to its acid in weeks in neutra l conditions and within days in alkaline conditions. The compound is phot olyzed relatively slowly with respect to biodegradation rates.

Diclofop acid biodegrades with ha lf-lives of weeks to months to HOE 30418 (up to 11% in aerobic conditions, 52% in anaerobic conditions), re sidues that are well sorbed to soil (11-69%), and carbon dioxide (1.4-29%). Un extracted residues in the labor atory studies are considered well sorbed to soil and not readily available because extraction solvents with a range of dielectric constants (from water to ben zene) could not extract them under a range of conditions.

Diclofop-methyl is non-volatile under fiel d conditions (vapor pressure of 1.9 × 10 -7 

### torr at 25°C). The compound is soluble in water at up to 0.39 mg/L (at 20°C) and lipophilic, with a logarithm of octanol-water partition coefficient (log K OW 

### ) of 4.77, indicating that bioaccumulation is a concern. A laboratory study shows that bioaccumula tion in fish is moderate, with a whole fish BCF of 430-450. However, 65-73% of accumulated residues depurated within one day and the instability of the ester is expect ed to limit its aquatic exposure.

In soil, K OC 

### values range from 11,000 to 25,000 L/kg, indi cating that diclofop-methyl is “hardly mobile” in soil (FAO, 2014). However, dicl ofop acid is moderately mobile in soil (K OC 

### values of 115 to 178 L/kg; MRID 42347801). Residues of di clofop-methyl and/or its acid leached to the 6-12” depth in a field study, indicating that di clofop residues may have increased mobility in some soils. However, diclofop-methyl and acid re sidues were not observed in soil pore water or ground water during a two-year prospective gr ound water (PGW) monitoring study, indicating
that residues are not mobile in some soils that are vulnerable to leaching (MRID 44532501).

Important means of transport off of agricultura l fields following application will include spray drift and runoff of residues dissolved or sorbed to suspended solids. Field dissipation data indicate that diclofop-methyl does not persist on the field (dissipa tion half-life of 3.5 days) but its acid is moderately persistent (dis sipation half-life of 28 days). Table 2 summarizes chemical properties and environmental fate parameters of diclofop-methyl (and not its acid, unless otherwise stated).

Table 2. Chemical Properties and Environmental Fate Parameters of Diclofop-methyl

Parameter Value Source
Selected Physical/Chemical Parameters
Molecular mass (molecular formula) 341.19 g/mol (C 16 

### H 14 

### Cl 2 

### O 4 

### ) (Calculated)
Vapor pressure (25°C) 1.9 x 10 -7 

### torr MRID 47973609
Aqueous solubility (20  C) 0.39 mg/L MRID 47973608
Henry’s Law Constant (25°C) 2.2 x10 -7 

### atm-m 3 

### /mol (Calculated)

### Page 9 of 50 Parameter Value Source
Log octanol-to-water partition coefficient (log K O W 

### ) 4.77 MRID 47973607

Dissociation constant (pKa) None MRID 48100402

Persistence in Water
Hydrolysis half-life 21°C: 2,650 d (pH 5), 21 d (pH 7), 1.9 d (pH 9) MRID 71389

25°C: 363 d (pH 5), 32 d (pH 7), 0.52 d (pH 9) MRID 41573309

Aqueous photolysis half-life (25  C) 22 d MRID 41573307
Anaerobic aquatic metabolism halflife (24-25  C) <1 d (pH 7.7-8.3) MRID 40806307

Persistence in Soil

Aerobic soil metabolism half-life (20-22°C) 2.1 d (IORE A 

### ; biphasic degradation; pH 6.8) 6.4 d (IORE A 

### ; biphasic degradation; pH 5.2) MRID 38861

<1 d (4 soils of pH 5.0-7.2) MRID 41573310
Photolysis half-life in soil (25  C) 100 d MRID 41573308

Mobility
Organic carbon-normalized soilwater partition coefficients (K OC 

### ) 11,000, 14,000, 15,000, 25,000 L/kg OC 

### MRID 40806308

Field Dissipation
Terrestrial field dissipation half-life; leaching depth (ester plus acid) CA Hanford sandy loam soil; pH 6.3: 2.6 d (barley crop), 3.5 d (bare soil) 0-6” depth (barley), 6-12” depth (bare soil) MRID 42252101

Prospective ground water monitoring results Diclofop-methyl and its acid were not detected (LOD=1 μg/L) in soil pore water or ground water up to 2 years after application MRID 44532501

Activated sludge metabolism No effects were observed for activated sludge biota at concentrations 0.1-100 mg/L MRID 107473

Fish Bioconcentration

Fish bioconcentration factors (steady-state, total residues); depuration rate 54-64 (edible), 930-1000 (inedible), 430-450 (whole fish); 65-73% depuration in 1 day [MRID 45878201] B

A IORE is the “indeterminate-order rate equation” kinetics model.

B Studies with MRIDs in brackets are provisional until reviewed.Page 10 of 504.1. Transformation ProductsDiclofop acid has a pKa of 3.43, indicatingthat it is anionic in environmentalconditions (MRID 42461501). The acid’s log KOWis 2.81at pH 5 and 0.70 at pH 7, indicating that bioaccumulation is not aconcern (MRID 40806306). It issoluble in water up to 23 mg/L at pH7, 22°C (MRID 40806302). As stated above, it ismoderately mobile in soil and biodegrades with half-lives ofweeks to months.Table3lists the degradates of diclofop-methyl,including their maximum and final concentrations. Major degradates include diclofopacid,HOE 30418, carbon dioxide, residues that arewell sorbed to soil, and an unidentified compound similar to diclofop-methyl.Table 3. Diclofop-methyl and Its Environmental Transformation Products.ACode Name/SynonymChemical NameChemical StructureStudyGuidelineMRIDSystemMaximum%AR (day)Final %AR(studylength)PARENTDiclofop-methylHOE 23408IUPAC:2-(4-(2',4'-dichlorophenoxy)-phenoxy)-methylpropanoateCAS No.:51338-27-3Formula:C16H14Cl2O4MW:341.19 g/molSMILES:C1=C(C=C(C(=C1)OC2=CC=C(C=C2)OC(C(=O)OC)C)Cl)ClMAJOR (>10%) TRANSFORMATION PRODUCTSDiclofopDiclofop acidHOE 21079IUPAC:2-(4-(2',4'-dichlorophenoxy)-phenoxy)-propanoic acidFormula:C15H12Cl2O4MW:327.16 g/molSMILES:C1=C(C=C(C(=C1)OC2=CC=C(C=C2)OC(C(=O)O)C)Cl)Cl835.212071389pH 761%(30 d)61%(30 d)pH 988%(2.8 d)88%(2.8 d)41573309pH 5 4.6% (30 d) 4.6% (30 d)pH 749%(30 d)49%(30 d)pH 9100%(18 d)99%(30 d)835.410038861sand63%(1-4 d)14%(32 d)sandy clay68%(4 d)54%(32 d)41573310sandy loam87%(4 d)12%(100 d)silt loam80%(1 d)4.1% (100 d)loamy sand83%(2 d)23%(100 d)sandy loam81%(2 d)17%(100 d)835.4400 40806307 pond system106%(7 d)33%(168 d)Page 11 of 50Code Name/SynonymChemical NameChemical StructureStudyGuidelineMRIDSystemMaximum%AR (day)Final %AR(studylength)HOE 304184-(2,4-dichlorophenoxy)-phenolFormula:C12H8Cl2O2MW:255.10 g/molSMILES:C1=C(C=C(C(=C1)OC2=CC=C(C=C2)O)Cl)Cl835.410038861sand11%(16 d) 9% (32 d)sandy clay 1% (16-32 d) 1% (16-32 d)41573310sandy loam 4.1% (32 d) 0.8% (100 d)silt loam 0.7% (16 d)<LOD (100 d)loamy sand 1.9% (64 d)1.6% (100 d)sandy loam 1.8% (32 d)0.8% (100 d)835.4400 40806307 pond system52%(168 d)52%(168 d)UnidentifiedcompoundsNANA835.2240 41573307 irradiated56%(7 d)B56%(7 d)BCarbon dioxideIUPAC:Carbon dioxideFormula:CO2MW:44 g/molSMILES:C(=O)=O835.2240 41573307 irradiated 9.6% (7 d)9.6% (7 d)835.2410 41573308 irradiated 5.7% (39 d) 5.7% (39 d)835.410038861sand18%(104 d)18%(104 d)sandy clay29%(104 d)29%(104 d)41573310sandy loam21%(100 d)21%(100 d)silt loam17%(100 d)17%(100 d)loamy sand12%(100 d)12%(100 d)sandy loam 1.4% (100 d) 1.4% (100 d)835.4400 40806307 pond system 4.7% (168 d) 4.7% (168 d)UnextractedresiduesNA NA835.410038861sand69%(64 d)69%(64 d)sandy clay34%(64 d)34%(64 d)41573310sandy loam42%(100 d)42%(100 d)silt loam42%(100 d)42%(100 d)loamy sand29%(100 d)29%(100 d)sandy loam37%(100 d)37%(100 d)835.4400 40806307 pond system11%(168 d)11%(168 d)AAR means “applied radioactivity”. MW means “molecular weight”. LOD means “limit of detection”. NA means “not applicable”.BChemical is structurally similar to diclofop-methyl.

### Page 12 of 50 

# 5. Receptors

Consistent with EFED’s standard methodology, the risk assessment for diclofop-methyl will rely on a surrogate species approach. Toxicological data generated from surrogate test species, which are intended to be representative of broad taxono mic groups, are used to ex trapolate to potential effects on a variety of species (receptors ) included under these taxonomic groupings.

The Agency evaluates the potential for adverse eff ects as a result of diclofop-methyl usage. The most sensitive endpoint for each taxon is used for RQ calculations. Assessment endpoints include direct toxic effects on the survival, repr oduction, and growth of terrestrial and aquatic life, as well as indirect effects, such as reduction in prey base a nd/or modification of habitat. The evaluated taxa include freshwater fish, freshwat er aquatic invertebrates, birds, small mammals, terrestrial invertebrates, alg ae, and terrestrial plants.

Acute (short-term) and chronic (long-term) toxi city information is characterized based on registrant-submitted studies. Other sources of information, including use of the acute probit dose response relationship to establish the probability of an individual effect and reviews of the Ecological Incident Information System (E IIS), are conducted to further refine the characterization of potential ec ological effects associated with exposure to diclofop-methyl.

Diclofop-methyl is highly toxic on an acute ba sis to freshwater fish and invertebrates. Supplemental information suggests that diclofop -methyl may be highly toxic to the eastern oyster; however, there are no estuarine marine fish or invertebrate data av ailable. In a chronic test, diclofop-methyl affected larval fish growth at 15 ppb ( NOAEC=7.5 ppb). In a waterflea lifecycle test, diclofop-methyl aff ected reproduction at 166 ppb (NOAEC=64 ppb).

The primary degradation product, diclofop acid, is only slightly toxic to freshwater fish. A study with the rainbow trout provides information on th e free acid metabolite of diclofop-methyl. The 96-hr LC 50 

### was determined to be 21.9 ppm ( 19.3-24.9) with an NOAEC of 13.5 ppm.

Diclofop-methyl is practically non-toxic to birds on an acute basis. There were no chronic effects to birds (NOAEL=200 ppm in both studies). Diclof op-methyl is moderately toxic to mammals on an acute basis. Diclofop-methyl is toxic to terrestrial plants , especially monocots (grasses and sedges).

Uncertainty exists for risk to terrestrial invertebrates (honey b ee) because no toxicity data are available. Diclofop-methyl is a systemic herb icide and could pose risk to bees. Also, only one aquatic plant study (growth inhibition using duc kweed) has been submitted for diclofop-methyl or diclofop acid. Results indi cate no inhibition above 50% (L C50 for frond number was 1.3 mg/L time-weighted average mean-measured con centrations) with an NOAEC of 1.0 mg/L timeweighted average mean-measured concentration.

Table 4 and Table 5 provide a summary of the aquatic and terrestrial taxonomic groups, respectively, and most sensitive surrogate species tested to characterize the potential acute and chronic ecological effect s of diclofop-methyl.

### Page 13 of 50 

## 5.1. Effects to Aquatic Organisms

Table 4. Summary of the Most Sensitive Endp oints from Aquatic Toxicity Studies for Diclofop-methyl

Taxonomic

Group Study Type Surrogate Species Toxicity
Value ( μ g ai/L) Acute Toxicity
Classification +Source

Freshwater fish Acute Bluegill sunfish (Lepomis macrochirus) 96 hr LC 50 = 150 ppb (0.15 ppm) Highly toxic 41606301

Smith & Schweitzer,
1990

Chronic Fathead minnow (Pimephales promelas) NOAEC= 7.5 ppb (0.075 ppm) (Based on wet weight) N/A 43284601 Dionne, 1994

Freshwater invertebrates Acute Water Flea ( Daphnia magna ) 48 hr EC 50 = 370 ppb (0.37 ppm) Highly toxic 41606304 Smith & Schweitzer,
1990

Chronic Water Flea NOAEC= 64 ppb (0.064 ppm) N/A 41737902 Smith, 1990

Estuarine/marine
fish Acute Sheepshead Minnow ( Cyprinodon variegatus ) No data N/A N/A

Chronic Sheepshead Minnow No data N/A NA

Estuarine/marine
invertebrates Acute Mysid Shrimp ( Americamysis bahia ) No data N/A N/A

Chronic Mysid Shrimp No data N/A N/A

Aquatic plants and algae Vascular Duckweed ( Lemna gibba ) No inhibition >50% (LC50 for
frond number was 1.295 with
an NOAEC of 1.0 mg/L Time-weighted

average (TWA) concentrations) Supplemental 45541703

Nonvascular Green Algae ( Pseudokirchneriella subcapitata ) No data N/A N/A

+ for study classifications see Appendix B

### Page 14 of 50 

### A toxicity study with the rainbow trout provide s information on the free acid metabolite of diclofop-methyl. The 96-hr LC 50 

### was determined to be 21.9 ppm (19.3-24.9) with an NOAEC of 13.5 ppm, which is less toxic than the pa rent compound by two orders of magnitude.



## 5.2. Effects to Terrestrial Organisms

Table 5. Summary of the Most Sensitive Endp oints from Terrestrial Toxicity Studies for Diclofop-methyl

Taxonomic

Group Study Type Surrogate Species Toxicity Value (all units in terms
of measured active ingredient) Acute Toxicity
Classification +Source

Birds Acute Northern
Bobwhite (Colinus virginianus) Acute Oral LD 50 > 2250 mg ai/kg-bw Practically
non-toxic 40072903
Hinken et al.

, 1986

Sub-acute dietary Northern
Bobwhite (Colinus virginianus) Acute Dietary LC 50 >13,000 ppm Practically
non-toxic Acc. No. 097117 Roberts,1977

Chronic Northern
Bobwhite (Colinus virginianus) NOAEL = 200 ppm
No effects N/A Acc. No. 098297 and
243472

Mallard duck (Anas platyrhynchos) NOAEL = 200 ppm No effects N/A Acc. No. 098297 and
243472

Mammals Acute Oral Laboratory rat ( Rattus norvegicus ) LD 50 = 568 mg/kgbw Slightly toxic 097107

Acute
Inhalation Laboratory rat ( Rattus norvegicus ) LC 50 >1.36 mg/L N/A *Footprint
database

Chronic Laboratory rat ( Rattus norvegicus ) NOAEL = 30 ppm N/A 097111

Insects Acute

contact Honey bee ( Apis mellifera
L. ) 48 hr LD50 >100ug/bee Practically
non-toxic *Footprint
database

Terrestrial Soil Invertebrate Acute Earthworm ( Lumbricus
terrestris ) 14 da LC50 >500 N.A *Footprint
database

Terrestrialplants nontarget Seedling Emergence Lettuce ( Lactuca
sativa )
Dicot EC 25 = 0.792 lb ai/A Plant dry weight N/A 41606306 Chetram,
1990

Ryegrass ( Lolium sp. )
Monocot EC 25 = 0.012 lb ai/A Plant height N/A 41606306 Chetram,
1990

### Page 15 of 50 Taxonomic

Group Study Type Surrogate Species Toxicity Value (all units in terms
of measured active ingredient) Acute Toxicity
Classification +Source

Vegetative Vigor Lettuce ( Lactuca
sativa )
Dicot EC 25 = 1.0 lb ai/A Plant dry weight N/A 41606305 Chetram,
1990

Ryegrass & Corn ( Zea mays )
Monocot EC 25 = 0.10 lb ai/A Plant height N/A 41606305 Chetram,
1990 *http://www.eu-footprint.org/ppdb.html + for study classifications see Appendix B


## 5.3. Ecological Incidents

The ecological incident information system (EIIS ) is an OPP database that houses ecological incidents that have been repor ted to the Agency. When ava ilable, EIIS includes date and location of an incident, type and magnitude of effects observed in various species, use(s) of pesticides known or suspected of contributing to the inci dent, and results of any chemical residue analysis or other analyses conducted during in cident investigation. EIIS incidents are categorized according to the certai nty that the incident resulted from pesticide exposure. The Avian Monitoring System (AIMS) is a database administered by the Amer ican Bird Conservancy that contains publicly available data on reported avian incidents involving pesticides. Many of
the incidents listed in this data base are also in the EIIS.

Reported incidents from the EIIS database included damage to non- target terrestrial plants and mortality to fish.

Table 6. EIIS Pesticide Summary Repo rt for Diclopfop-methyl (110902)

Incident# Date County,
State Certainty Legal. Appl.
Method Species Response Rt. Exposure Magnitude

AQUATIC

Soybean I003826-
017 8/15/1994 Rowan, NC 2 RU Unknown
fish Mortality Runoff Unknown

PLANTS

N/R I013636-
027 2/4/2002 Washington,
OR 2 UN tulips Plant damage Treated directly 6 acres

Wheat, spring I013942-
001 3/1/2003 San Diego,
CA 3 MA Spray Wheat, spring Plant damage Treated directly 60 acres

Wheat,
winter I013103-
033 4/19/2002 Monroe, AR 2 RU Broadcast Wheat Plant damage Treated directly All 50 acres

I013942-
005 1/29/2003 Phillips, AR 2 RU Broadcast Wheat,
winter Plant damage Treated directly 1785 acres

I013942-
004 2/18/2003 Lonoke, AR 2 RU Broadcast Wheat,
winter Plant damage Treated directly 105 acres

I013942-
003 3/14/2003 Yolo, CA 2 RU Spray Wheat,
winter Plant damage Treated directly 78 acres

I013942-
002 3/4/2003 Craighead,
AR 2 RU Spray Wheat,
winter Plant damage Treated directly 150 acres

Certainty code: 0=Unrelated, 1=Unlikely, 2=Possible, 3 =Pr obably, 4=Highly Probable Legality Code: RU=Registered Use, M=Misuse, MA=Misuse (Accidental), MI=Misuse (Intentional), U=Unknown

### Page 16 of 50 

### Terrestrial Plants Three possible incidents in Arkansas were re ported in 2003, all involving plant damage to 2040 acres of winter wheat and all from registered use applications (I013942-002, -004, -005). Also in 2003, 78 acres of winter wheat was po ssibly damaged in Yolo CA (I013942-003 ).



### In another incident (I013942-001) , also in 2003, 60 acres of spring wheat was damaged in San Diego CA. This incident was cl assified as “probable” but was likely an accidental misuse.

In 2002, 6 acres of tulips were damaged in Wa shington OR under possible incident I013636-027.

Fish One incident involving fish was reported. The incident (I003826-017) occu rred in Rowan NC in 1994 where an undetermined number of fish were kill ed after a runoff event after a registered use application to soybeans. The re ported likelihood was “possible.”


# 6. Exposure Pathways of Concern

The conceptual model will consider the parent compound and its acid for the drinking water exposure assessment and ecological risk assessment.

The environmental fate properties and use patterns of diclofop-methyl indi cate that direct spray, spray drift, and runoff represent potential transport mechanisms of diclofop residues to aquatic and terrestrial organisms.

Drinking water and inhalation e xposure pathways were screen ed using the SIP (Screening Imbibition Program) and STIR (Screening Tool for Inhalation Risk) screening methods and were found not to be exposure pathways of concern (no LOC exceedances are expected). Appendix C
and D contain details on the SIP a nd STIR analyses. SIP and STIR are described in detail at: http://www.epa.gov/oppefed1/ models/terrestrial/index.htm

. 

# 7. Analysis Plan

7.1. Stressors of Concern

Ecological Risk Assessment

The stressor of ecological concern for terrestria l and aquatic organisms is diclofop-methyl only, with the exception that diclofop acid is of concern for terrestria l plants. Diclofop acid is two orders of magnitude less toxic to the Rai nbow Trout than diclofop-methyl. Additional ecotoxicity data on diclofop acid ar e not available. Ecotoxicity data for cyhalofop-butyl, which is in the same chemical class (aryloxy-phe noxy-propionates), and cyhalo fop acid indicate that the acid is two orders of magnitude less toxic than the parent compound to Bluegill Sunfish. However, the toxicity of the acid is similar to th at of the parent for corn and barnyard grass. Therefore, the cyhalofop acid is a residue of con cern for terrestrial plants , especially monocots. Also, ECOSAR (v.1.11) results indica te that diclofop acid is estimat ed to be much less toxic to aquatic organisms than diclofop-methyl. These li nes of evidence indicate th at the degradates of diclofop-methyl are likely to be much less to xic than the parent compound to aquatic and

### Page 17 of 50 

### terrestrial organisms, with the possible exception of terrestrial pl ants, especially monocots. The diclofop-methyl residues of concer n may be reevaluated pending re ceipt and review of additional environmental fate and toxicity data.

Drinking Water Exposure Assessment

The drinking water exposure assessment conducted to support human hea lth risk assessment of diclofop-methyl will incorporate model estimates of diclofop-methyl residues of concern, which are the parent compound and its acid (USEPA, 2000), in surface and ground waters. Exposure estimates reported for potential acute, chronic, and cancer assessment are the 1-in-10-year peak, 1-in-10-year annual mean, and 30-year mean in a vulnerable reservoir with a drinking water intake. The diclofop-methyl resi dues of concern may be reevalua ted pending receipt and review
of additional environmental fate and toxicity data.



## 7.2. Measures of Exposure

EFED will use standard available models to evaluate potential exposures to aquatic and terrestrial organisms as described at http://www.epa.gov/pesticides/science/models_db.htm . For surface water, the measure of exposure for acute risk s is the 1-in-10-year peak concentration at a site more vulnerable than 90% of sites where a pe sticide use site occurs. For chronic risks, the measures of exposure are 1-in-1 0-year 21-day and 60-day means. For terrestrial risks the measure of exposure is the peak exposure on (and at the e dge of) the field.



## 7.3. Measures of Effect

Toxicity data presented in Section 4 of this pr oblem formulation will be used to calculate risk quotients. Any additional information submitted by th e registrant or found in the open literature prior to conduct of the risk assessment will also be considered. The open literature studies are identified using EPA’s ECOTOXicol ogy database (ECOTOX) (USEPA, 2007 c ), which employs a literature search engine for lo cating chemical toxicity data for aquatic life, terrestrial plants,
and wildlife. The evaluation of both sources of da ta can also provide insi ght into the direct and indirect effects of pesticides on biotic communities from loss of species that are sensitive to the chemicals and from changes in structure and functional characteristics of the affected
communities.


# 8. Endangered Species Assessments

Consistent with the Agency’s responsibility under the Endangered Species Act (ESA), the Agency will evaluate risks to federally listed th reatened and/or endangere d (listed) species from registered uses of pesticides in registration re view. The process for evaluating potential risks to listed species is further described at http://www.epa.gov/oppfead1/enda nger/litstatus/riskasses.htm

.

### Page 18 of 50 

# 9. Endocrine Disruptor Screening Program

As required by FIFRA and FFDCA, EPA reviews num erous studies to asse ss potential adverse outcomes from exposure to chemicals. Collectiv ely, these studies includ e acute, subchronic and chronic toxicity, including asse ssments of carcinogenicity, ne urotoxicity, developmental, reproductive, and general or systemic toxicity. These studies include e ndpoints which may be susceptible to endocrine influe nce, including effects on endocri ne target organ histopathology, organ weights, estrus cyclicity, sexual maturatio n, fertility, pregnancy rates, reproductive loss, and sex ratios in offspring. For ecological hazard assessments, EPA evaluates acute tests and chronic studies that assess gr owth, developmental and reprod uctive effects in different taxonomic groups. As part of its most recent regi stration decision, EPA reviewed these data and selected the most sensitive endpoi nts for relevant risk assessment scenarios from the existing hazard database. However, as required by FFDCA section 408(p), diclofop-methyl is subject to the endocrine screening part of the Endocri ne Disruptor Screeni ng Program (EDSP).

EPA has developed the EDSP to determine whet her certain substances (including pesticide active and other ingredients) may have an effect in humans or wildlife similar to an effect produced by a “naturally occurring estrogen, or ot her such endocrine effect s as the Administrator may designate.” The EDSP employs a two-tiered approach to making th e statutorily required
determinations. Tier 1 consists of a battery of 11 screening assays to identify the potential of a chemical substance to interact with the estrog en, androgen, or thyroid (E, A, or T) hormonal systems. Chemicals that go th rough Tier 1 screening and are found to have the potential to interact with E, A, or T hormonal systems will proceed to the next stag e of the EDSP where EPA will determine which, if any, of th e Tier 2 tests are necessary base d on the available data. Tier 2 testing is designed to identify a ny adverse endocrine-related eff ects caused by the substance, and establish a dose-response relationship between the dose and the E, A, or T effect.

Under FFDCA section 408(p), the Agency must screen all pesticide chemicals. Between October 2009 and February 2010, EPA issued test orders/data call-ins for the first group of 67 chemicals, which contains 58 pest icide active ingredient s and 9 inert ingredients. A second list
of chemicals identified for EDSP sc reening was published on June 14, 2013 1 

### and includes some pesticides scheduled for registration review and chemicals found in water

. Neither of these lists
should be construed as a list of know n or likely endocri ne disruptors.

Diclofop-methyl is on List 1 for which EPA has received all the required Tier 1 assay data. The Agency is currently reviewing a ll assay data received for the a ppropriate List 1 chemicals and planning to make the conclusions of those re views available in early 2015. For further information on the status of the EDSP, the policies and procedures, the lists of chemicals, future lists, the test guidelines and the Tier 1 screening battery, pleas e visit our website. 2

1 See http://www.regulations.gov/#!documentDetail;D=EPA-HQ-OPPT-2009-0477-0074 for the final second list of

chemicals.

2 http://www.epa.gov/endo/

### Page 19 of 50 

# 10. Preliminary Identification of Data Gaps

10.1. Environmental Fate

Table 7 and Table 8 identify environmental fate studies by their Master Record Identification (MRID) number that offer data for each guideline requirement, as well as study classifications
and whether or not further data are needed in order to support risk assessment.

Table 7. Submitted Environmental Fa te Data for Diclofop-methyl

OCSPP
Guideline Data Requirement Submitted Studies (MRID) Study
Classifications Sufficient
for
EFED? Current Additional Data Need

835.2120 Hydrolysis Acc. 97120 Unacceptable Yes -- 71389 Acceptable 41573309 Acceptable 835.2240 Aqueous photolysis 107471 Unacceptable Yes -- 41573307 Acceptable 835.2410 Soil photoly sis 107470/87811 Un acceptable Yes -- 41573308 Acceptable

835.4100 Aerobic soil
metabolism 38861 Supplemental Yes -- 87826 Unacceptable 41573310 Supplemental

835.4200 Anaerobic soil
metabolism Acc. 97118 Non-guideline Yes --

835.4300 Aerobic aquatic
metabolism (no studies) -- No A guideline-compliant study of two
sediments and their associated waters
is needed.

835.4400 Anaerobic aquatic
metabolism 87826 Unacceptable No A guide line-compliant study of one
sediment and its associated water is
needed. 40806307 Acceptable 42734201 Unacceptable

835.1230
835.1240 Adsorption/ desorption and leaching 40520301 Supplemental Yes -- 40806308 Acceptable 42347801 Unacceptable

835.6100 Terrestrial field dissipation 87824/87825 Unacceptable Yes
-- 87828 Unacceptable

156479/40520302/ 40806309 Unacceptable

42252101 Supplemental 835.6200 Aquatic field dissipation 45695, 45696, 45697, 84656, 87837, 87808, 134716, 134717 Pre-GLP *

835.7100 Prospective ground water monitoring 44532501 Acceptable Yes --

850.1730 Fish
bioconcentration 84654, 87812 Pre-GLP * Yes -- 41996903 Unacceptable 45878201 Supplemental

### Page 20 of 50 OCSPP
Guideline Data Requirement Submitted Studies (MRID) Study
Classifications Sufficient
for
EFED? Current Additional Data Need

850.6100 Analytical method in water (no reports) -- No An initial and an independent laboratory validation report are needed for an analytical method in
water for the ester and its acid with an LOQ less than 7.5 μg/L (the lowest toxicological level of concern). * “Pre-GLP” means that the study predat es the 40 CFR Part 160 regulations and is not likely to be acceptable according to current gu ideline standards.



### Table 8. Submitted Environmental Fa te Data for Diclofop Acid

OCSPP
Guideline Data Requirement Submitted Studies (MRID; Degradate) Study
Classifications Sufficient
for EFED? Current Additional Data Need

835.2240 Aqueous photolysis Acc. 244465 Unacceptable Yes An aq ueous photolysis study is not
needed. 835.2410 Soil photolysi s Acc. 244465 Unacceptable Yes A soil photolysis study is not
needed. 835.1230 Adsorption/ desorption 40806308 Acceptable Yes
-- 42347801 Supplemental



### Environmental fate data gaps for diclofop-met hyl include an aerobic aquatic metabolism study (OCSPP 835.4300), an anaerobic aquatic metabo lism study (835.4400) of one system, and an analytical method in water (OCSPP 850.6100) and asso ciated independent labo ratory validation. The aquatic metabolism data are needed to estimat e aquatic exposure from residues that cross the
100-foot buffer to reach water bodies. The amount s of diclofop-methyl a nd its degradates that may occur in aquatic systems are uncertain with only one anaerobic aqua tic metabolism half-life and no aerobic aquatic metabolism half-lives. In the absence of additional data, conservative assumptions would be made regard ing the degradation of diclofop- methyl in aquatic systems. The analytical method in water is need ed to support poten tial monitoring.

Additional aqueous photolysis and soil photolysis st udies are not needed for diclofop acid mainly because the compound is not a residue of concern for aquatic organisms.



## 10.2. Ecological Effects

Table 9 and Table 10 identify ecological effects studies by MRID that offer data for each guideline requirement, as well as study classifications and whether or not further data are needed in order to support risk assessment. Rationale for the additional data requested is presented
below the tables.

### Page 21 of 50 

### Table 9. Submitted Aquatic Ecological Effects Data for Diclofop-methyl

OCSPP
Guideline Data Requirement Submitted
Studies (MRID) Study
Classifications Are data
needed to conduct risk
assessment? Current Addition al Data Need

850.1010 Freshwater
invertebrate acute toxicity 41573303 Acceptable No

850.1025
850.1035
850.1045
850.1055 Saltwater invertebrate acute toxicity None N/A Yes See explanation below

None N/A

None N/A

850.1075 Freshwater
fish acute toxicity 41573302 Acceptable No
41606301 Acceptable

850.1075 Saltwater fish acute toxicity None N/A Yes See explanation below

850.1300 Freshwater invertebrate life cycle 41737902 Acceptable No

850.1350 Saltwater
invertebrates life cycle None N/A No

850.1500 Freshwater fish life cycle 43284601 Acceptable No

850.1400 Freshwater
fish early-life stage 246021 Acceptable No

850.1400 Saltwater fish early-life stage N/A N/A No

850.4400 Aquatic plant growth: vascular plants 45541703 Duckweed Supplemental No

850.4500 Aquatic Plant Growth: algae None N/A Yes See explanation below

850.4550 Cyanobacteria (Anabaena flos-aquae) None N/A Yes See explanation below



### Table 10. Submitted Terrestrial Ecologica l Effects Data for Diclofop-methyl

OCSPP
Guideline Data Requirement Submitted
Studies (MRID) Study
Classifications Are data
needed for
risk
assessment? Current Additional Data Need

850.2100 Avian oral toxicity 097117 Supplemental No
40072903 Acceptable

### Page 22 of 50 OCSPP
Guideline Data Requirement Submitted
Studies (MRID) Study
Classifications Are data
needed for
risk
assessment? Current Additional Data Need

850.2200 Avian dietary toxicity 40072901 Acceptable No
40072902 Acceptable

850.2300 Avian reproduction 098297
243472 Supplemental (waivers were granted) No

850.3020 Honey bee

acute contact toxicity No data N/A Yes See explanation below

850.3030 Honey bee
residue on foliage N/A N/A No

850.3040 Field testing for pollinators N/A N/A No

850.4100 Terrestrial plant toxicity: seedling

emergence 41606306 Acceptable No

850.4150 Terrestrial plant toxicity: vegetative vigor 41606305 Acceptable No

Nonguideline Honeybee
acute oral larval N/A N/A Yes See explanation below

Nonguideline Honeybee
acute adult
oral N/A N/A Yes See explanation below

Nonguideline Earthworm

acute N/A N/A No



### At the present time, all of the data requirements have been fulfilled except for acute
estuarine/marine fish and invertebrate studies (850.1025, 850.1035 and 850.1075), aquatic plant growth studies (850.4500 & 850.4550), an acute c ontact bee study (850.3020) , and acute adult oral and larval studies with the honeybee. Wit hout these data, assumptions will be made which may be overly conservative.

Guidelines 850.1025, 850.1035 & 850.1075 No data have been submitted regarding acute toxici ty to estuarine/marine fish or invertebrates. Although applications are prohibited within 100 ft of any wate r bodies, diclofop-methyl is highly acutely toxic to freshwater fish and invertebrates. In addition, use on golf courses can occur near estuarine areas. Acute studies with the sheep shead minnow, mysid and oys ter (shell deposition)
are needed.

### Page 23 of 50 

### Guidelines 850.4500 & 850.4550 Aquatic plant testing is required for any herbicide that has outdoor non-residential terrestrial uses that may move off-site by runoff, by drift, or that is applied direct ly to water. Only one aquatic plant study ( Lemna gibba G3) has been submitted for diclofop-methyl or diclofop acid. The test guideline requirements have not been fulfilled.

Guideline 850.3020 No data have been submitted regarding toxicity to bees or other beneficial insects. A honeybee acute contact toxicity study is needed to assess risk to bees and othe r beneficial insects.

Non-Guideline Adult Oral and Larval Studies In keeping with the Agency’s proposed new para digm for determining potential adverse effects to insect pollinators from conventional pestic ides (USEPA 2012), two additional studies are being requested in addition to th e guideline acute contact study. An acute adult oral toxicity study (following OECD 213) and a larval oral toxicity study (fo llowing OECD 237) are necessary to evaluate the potential for diclof op-methyl to adversely affect bees and other pollinators. Several target crops are considered attractive to honey bees and this is a systemic chemical that is transported throughout the plant. Thus, residues may be available to pollinators via pollen and/or nectar. For assessment pur poses, EFED will estimate exposures through pollen and nectar, thus EFED is not asking for polle n and nectar residue data at this time.

Study Title: Pollinator Acute Oral Toxicity, Adult (single dose) Rationale for Requiring the Data

Terrestrial invertebrates are likely to be impacted if exposed given diclofop-methyl’s use as an herbicide in various use settings . Diclofop-methyl may be transf erred to pollen and/or nectar of treated plants and subsequently brought back to the hive. Therefore, potential effects to adult honeybees from oral exposure could exist. Currently available to xicity studies do not address possible effects of oral exposure on a dult honeybee survival. Because of the potential for pollen and nectar to be contaminated and subsequently brought ba ck to the hive, it is important to determine the toxicity of this compound to adult honeybees. Therefore, a nonguideline adult honeybee study is needed to measure acute oral toxicity.

The Office of Pesticide Programs has made ava ilable a guidance regarding ecological testing for invertebrates with the honeybee. These can be found at: http://www2.epa.gov/pollinatorprotection/pollinator-risk-assessment-guidance

. Practical Utility of the Data

How will the data be used? Data will be used to assess potential risk to non-target listed a nd non-listed terrestrial invertebrates, including pollinators, from acute e xposures to diclofop-methyl . The data will be
used to reduce uncertainties associated with the registration review risk assessment for terrestrial invertebrates and will improve EP A’s understanding of the potential effects on terrestrial species. If acute oral effects are not submitted, risks to terrestrial insects from acute exposure will be assumed.

### Page 24 of 50 

### How could the data impact the Agency’s future decision-making?
The data EPA intends to call in will inform the determination required under FIFRA or the ESA as to whether continued registration of a pesticide is likely to result in unreasonable adverse effects to non-target spec ies or is not likely to jeopardize listed or endangered species
or its critical habitat. The lack of these data will limit the flexibility that the Agency and registrants have in coming in to compliance w ith the ESA and could result in significant use restrictions. In addition, the la ck of these data may result in assumed risk and potential mitigation of diclofop-methyl formulations under FIFRA.

Study Title: Pollinator Acute Oral Toxicity, Larvae (single dose) Rationale for Requiring the Data

Terrestrial invertebrates are likely to be impacted if exposed given diclofop-methyl’s use as an herbicide in various use settings . Diclofop-methyl may be transf erred to pollen and/or nectar of treated plants and subsequently brought b ack to the hive where larvae and pupae may be exposed. Therefore, potential effects to developing bees could exist, as eg g and larval stages of some of the pests are indicated to be the most sensitive stages, and developing bees may also be sensitive at these stages. Currently availabl e toxicity studies do not address possible effects on brood (larvae and pupae) survival. Because of the potential for pollen and nectar to be contaminated and subsequently brought back to the hive, it is important to determine the toxicity of this compound to brood. Theref ore, a non-guideline hone ybee larval study is needed to measure acute oral toxicity.

The Office of Pesticide Programs has made ava ilable a guidance regarding ecological testing for invertebrates with the honeybee. These can be found at: http://www2.epa.gov/pollinatorprotection/pollinator-risk-assessment-guidance

. Practical Utility of the Data

How will the data be used? Data will be used to assess risk to non-targ et listed and non-listed terrestrial invertebrate species. The data will reduce uncertainties a ssociated with the registration review risk
assessment for terrestrial invertebrates and w ill improve EPA’s understanding of the potential effects on terrestrial species. If acute oral e ffects are not submitted, risks to terrestrial insects from acute exposure will be assumed.

How could the data impact the Agency’s future decision-making? The data EPA intends to call-in will inform the determination required under FIFRA or the ESA as to whether continued registration of a pesticide is likely to result in unreasonable adverse effects to non-target spec ies or is not likely to jeopardize listed or endangered species
or its critical habitat. The lack of these data will limit the flexibility that the Agency and registrants have in coming into compliance with the ESA and could result in significant use restrictions. In addition, the la ck of these data may result in assumed risk and potential mitigation of diclofop-methyl formulations under FIFRA.

### Page 25 of 50 

# 11. References

Food and Agriculture Organization of th e United Nations (FAO). 2014. Assessing soil contamination A reference manual; Parameters of pesticides that influence processes in the soil. Agriculture and Cons umer Protection Department. http://www.fao.org/docrep/003/x2570e/x2570e06.htm

HRAC. 2010. The World of Herbicides Poster. www.hracglobal.com (accessed Aug. 1, 2012)

U.S. Department of Agriculture (USDA). 1996. S eefeldt, S., E. Fuerst, G. Irzyk, D. Gealy, A. Shukla, D. Hoffman, and B. Brewster. Diclofop-Resistant Avena Fatua from the Willamette Valley of Oregon. International Weed Control Congress Proceedings. Accepted for publication: Jun. 24, 1996. Interpretive summary at: http://www.ncaur.usda.gov/research/ publications/publications.htm?seq_no_115=66579

Seefeldt, S., E. Fuerst, D. Gealy, A. Shukla, G. Irzyk, and M. Devine. 1996. Mechanisms of Resistance to Diclofop of Two Wild Oat ( Avena Fatua ) Biotypes from the Willamette Valley of Oregon. Weed Science, 44 : 776-781.

U.S. Environmental Protection Agency (USE PA). 1999. Dutta, S. Drinking Water Memorandum for Diclofop-methyl for the Reregistration El igibility Decision Document (RED). DP
barcode 260166. Memorandum from the Environm ental Fate and Effects Division to the Registration Division. Oct. 15, 1999.

USEPA. 2000. Piper, S. Diclofop-Methyl: Ou tcome of HED Metabolism Assessment Review Committee Meeting on 4/4/00. DP Barcode 264 794. Health Effects Division. Internal memorandum. Apr. 7, 2000.

USEPA. 2009. Guidance for Selecting Input Pa rameters in Modeling th e Environmental Fate and Transport of Pesticides. Version 2.1. U.S. Environmental Protection Agency, Office of Pesticide Programs, Environmental Fate and Effects Division, Oct. 22, 2009. www.epa.gov/oppefed1/models/water /input_parameter_guidance.htm

USEPA. 2012. White Paper in Support of the Proposed Risk Assessment Process for
Bees. Submitted to the FIFRA Scientific Advisory Panel for Review and Comment September 11-14, 2012. Office of Chemical Sa fety and Pollution Prevention Office of Pesticide Programs Environmental Fate and Effects Division, Environmental Protection Agency, Washington DC; Environmental Asse ssment Directorate, Pest Management Regulatory Agency, Health Canada, Ottawa, CN; California Department of Pesticide Regulation. www.regulations.gov/#!documentD etail;D=EPA-HQ-OPP-2012-0543-0004

United States Geological Survey (USGS). 2014. National Water-Quality Assessment (NAWQA) Program, Pesticide National Synthesis Pr oject, Pesticide Us e Maps – Diclofop. http://water.usgs.gov/nawqa/pnsp/usage/ maps/show_map.php?year=2011&map=DICLO FOP&hilo=L&disp=Diclofop (accessed Apr. 23, 2014)

### Page 26 of 50 

# APPENDIX A: Eco and Fate Bib liography for Diclofop-methyl

110902 Diclofop-methyl Eco Effects Bibliography

71-1 Avian Singl e Dose Oral Toxicity

MRID Citation Reference

38853 or
133065 Kramer; Hollander (1974) Acute Oral Toxicity of ... (Hoe 23408 O H AT) in Male Quails (Carrier Substance: Starch Suspension): A02061

. (Translation; unpublished study received 1974 under 6G1664; prepared by Hoechst, AG, W. Ger., submitted by American Hoechst Corp., Somerville , NJ; CDL:095400-A) or ACC 094682-B

133066 or
38854 Kramer; Hollander (1974) Acute Oral Toxicity of ... (Hoe 23408 O H AT) in Male Quails (Carrier Substance: Sesame Oil): A02055. (Translation; unpublished study received 1974 under 6G1664; prepared by Hoechst, AG, W. Ger., submitted by American Hoechst Corp., Somerville, NJ; CDL:095400-B)

133067 or
38855 Kramer; Hollander (1974) Acute Oral Toxicity of ... (Hoe 23408 O H AT) in Female Quails (Carrier Substance: Starch Suspension): A02059. (Translation; unpublished study received 1974 under 6G1664; prepared by Hoechst, AG, W. Ger., submitted by American Hoechst Corp., Somerville, NJ; CDL:095400-C)

133068 or
38856 Kramer; Hollander (1974) Acute Oral Toxicity of ... (Hoe 23408 O H AT) in Female Quails (Carrier Substance: Sesame Oil): A02060. (Translation; unpublished study received 1974 under 6G1664; prepared by Hoechst, AG, W. Ger., submitted by American Hoechst, Corp., Somerville, NJ; CDL:095400-D)

107441 Roberts, S.; Parke, G.; Charles, S. (1977) Acute Oral Toxicity of HOE-23408 Technical 95% in Bobwhite Quail: Laboratory No. 7E- 6135; A10868. (Unpublished study received May 26, 1978 un der 8340-11; prepared by Cannon Laboratories, Inc., submitted by American Hoechst Corp., Somerville, NJ; CDL:097117-B)

40072903 Hinken, C.; Grimes, J.; Jaber, M. (1986) Diclofop-Methyl Technical: (Code: HOE 023408 OH ZD95 0003): An Acute Oral Toxicity Study with the Bobwhite: Laboratory Project ID No. 125-140. Unpublished study prepared by Wildlife International Ltd. 27 p.

92036005 Dulak, L. (1990) Hoechst Celanese Corporation Phase 3 Summary of MRID 40072903. Diclofop-methyl Technical (Code: HOE 023408 OH ZD95 0003): An Acute Oral Toxicity Study with the Bobwhite: Lab. Project ID. No. 125-140. Prepared by WILDLIFE INTERNATIONAL, LTD. 16 p.



## 71-2 Avian Dietary Toxicity

MRID Citation Reference

38857 or
107442 Terrell, Y.; Parke, G.S.E. (1975) Report--Eight Day Dietary LC50 Study ofTechnical HOE-23408--Coturnix Quail and Mallard Ducks: Laboratory Nos. 4E5200; 4E-5201. (Unpub lished study received Aug 22, 1975 under 6G16 64; prepared by Cannon Laboratories, Inc., submitted by American Hoechst Corp., Somerville, N.J.; CDL:094682-F)

107454 Krize, J. (1978) Avian Dietary LC50 (5-day Dietary Exposure) of HOE-23408, 95%
Pure to Mallard Duck: La boratory No. 8E-1526. (U npublished study received Aug

### Page 27 of 50 17, 1978 under 8340-11; pre- pared by Cannon Laboratories, Inc., submitted by American Hoechst Corp., Somerville, NJ; CDL:097291-A)

40072901 Hinken, C.; Grimes, J.; Jaber, M. (1986) Diclofop-Methyl Technical: (Code: HOE 023408 OH ZD95 0003): A Dietary LC50 Study with the Bobwhite: Laboratory Project ID No. 125-138. Unpublished study prepared by Wildlife International Ltd. in cooperation with Ana- lytical Development Corp. 38 p.

40072902 Hinken, C.; Grimes, J.; Jaber, M. (1986) Diclofop-Methyl Technical: (Code: HOE 023408 OH ZD95 0003): A Dietary LC50 Study with the Mallard: Laboratory Project ID No. 125-139. Unpublished study prepared by Wildlife International Ltd. in cooperation with Analytical Development Corp. 36 p.

92036006 Dulak, L. (1990) Hoechst Celanese Corporation Phase 3 Summary of MRID 40072901. Diclofop-methyl Technical (Code: HOE 023408 OH ZD95 0003) A Dietary LC 50 Study with the Bobwhite: Lab. Project No. 125-138. Prepared by WILDLIFE INTERNATIONAL, LTD. 19 p.

92036007 Dulak, L. (1990) Hoechst Celanese Corporation Phase 3 Summary of MRID 40072902. Diclofop-methyl Technical (Code: HOE 023408 OH ZD95 0003) A Dietary LC 50 Study with the Mallard: Lab. Project No. 125-139. Prepared by WILDLIFE INTERNATIONAL, LTD. 19 p.

107443 Roberts, S.; Parke, G.; Charles, S. (1977) Avian Dietary LC50 5-day Dietary Exposure with 3-day Observation Period of Bobwhite Quail to HOE-23408 Technical 95%: Laboratory No. 7E-6136; A10867. (Unpublished study received May 26, 1978 under 8340-11; prepared by Cannon Laboratories, Inc., submitted by American Hoechst Corp., Somerville, NJ; CDL:097117-D) 

## 71-4 Avian Reproduction

MRID Citation Reference

94621 Lawatch, D.J. (1980) Letter sent to Richard F. Mountford dated Sep 30, 1980: Hoelon^RI avian reproduction studies; Your letter of August 11, 1980. (Unpublished study received Oct 7, 1980 under 8340-11; submitted by American Hoechst Corp., Somerville, N.J.; CDL:243473-A)

107457 Terrell, Y. (1978) Reproduction Study of HOE 23408 (Batch 76-01) in Bobwhite Quail: Laboratory No. 7E-7620; A15554. (Unpublished study received May 21, 1979 under 8F2085; prepared by Cannon Laboratories, Inc., submitted by American Hoechst Corp., Somerville, NJ; CDL:098297- C)

107458 Terrell, Y. (1978) Reproduction Study of HOE 23408 (Batch 76-01) in Mallard Ducks: Laboratory No. 7E-7621; A15553. (Unpublished study received May 21, 1979 under 8F2085; prepared by Cannon Laboratories, Inc., submitted by American Hoechst Corp., Somerville, NJ; CDL:098297- D)

40440901 Beavers, J.; Frank, P.; Jabe r, M. (1987) Diclofop-Methyl TechnicalSubstance: (Code: HOE 023408 OH ZD95 0003): A One-generation Reproduction Study with the Bobwhite (Colinus virginianus): Labo ratory Project No.: 125-135. Unpublished study prepared by Wildlife International Ltd. 220 p.

40440902 Beavers, J.; Frank, P.; Jabe r, M. (1987) Diclofop-Methyl TechnicalSubstance: (Code: HOE 023408 OH ZD95 0003): A One-generation Reproduction Study with the Mallard (Anas platyrhynchos): Labora- tory

### Page 28 of 50 Project No.: 125-136. Unpublished study prepared by Wild- life International Ltd. 220 p.

92036008 Dulak, L. (1990) Hoechst Celanese Corporation Phase 3 Summary of MRID 40440901. Diclofop-methyl Technical (Code: HOE 023408 OH ZD95 0003) A One-generation Reproduction Study with the Bob White (Colinus virginianus): Lab. Project ID. No. 125-135. Prepared by WILDLIFE INTERNATIONAL, LTD. 18 p.

92036009 Dulak, L. (1990) Hoechst Celanese Corporation Phase 3 Summary of MRID 40440902. Diclofop-methyl Technical (Code: HOE 023408 OH ZD95 0003) A One-Generation Reproduction Study with the Mallard (Anas platyrhynchos): Lab. Project ID. No. 125-136. Prepared by WILDLIFE INTERNATIONAL, LTD. 18 p.

130238 Eckert, J. (1979) Addendum to Report: Avian Reproduction study of HOE23408, 95% Pure, Batch #76-01-001 to Mallard Duck and Bob- white Quail: Laboratory No. 7E-7620 & 7E -7621. (Unpublished study received Oct 7, 1980 under 8340-11; prepared by Cannon Laboratories, Inc., submitted by American Hoechst Corp., Somerville, NJ; CDL:243473-B)


## 72-1 Acute Toxici ty to Freshwater Fish

MRID Citation Reference

76868 Knauf, W. (1978) The Acute Toxicity of HOE 21079 O H AT102 to the Rainbow Trout (Salmo gairdneri~Ri chardson): A16197 . (Unpublished st udy received May 21, 1981 under 8340-11; prepared by Hoechst AG, West Germany, submitted by American Hoechst Corp., Somerville, N.J.; CDL:245123-H)

107445 Knauf, W.; Schulze, E. (1978) The Effect of HOE 23408 O H AT002 (Active Ingredient) on Salmo gairdneri (Rainbow Trout): A13481. (Translation of doc. no. A13472; unpublished st udy received May 26, 1978 u nder 8340-11; prepared by Hoechst Aktiengesellschaft, W. Ger., su bmitted by American Hoechst Corp., Somerville, NJ; CDL:097117-F)

107446 or
133070 or
36860 Knauf, W. (19??) Toxicity of HOE 23408 3EC in Rainbow Trout (Salmo gairdneri): ?Submitter| AO 3692. (Trans lation; unpublished study received May 26, 1978 under 8340-11; submitted by American Hoechst Corp., Somerville, NJ; CDL:097117-G)

38859 or
107444 Knauf, (1975) Toxicity of HOE 23408 OH (Active Ingredient) in Rainbow Trout (Salmo gairdneri): AO 3693 . (Translation; un- published study received Aug 22, 1975 under 6G1664; submitted by American Hoechst Corp., Somerville, N.J.; CDL:094682-H)

107447 Knauf, W.; Schulze, E. (1978) Action of HOE 23408 O H AT002 (Active Ingredient) on Lepomis gibbosus (Pumpkinseed Sunfish): A13482. (Translation of document A13473; unpublished study r eceived May 26, 1978 under 8340-11; prepared by Hoechst Aktienge sellschaft, W. Ger., submit ted by American Hoechst Corp., Somerville, NJ; CDL:097117-H)

107448 Knauf, W. (1976) HOE 23408 O H EH065 (Emulsifiable Conc.): Effect on Lepomis gibbosus: A09917. (Translation of document no. AO8544; unpublished study received May 26, 1978 under 8340- 11; prepared by Hoechst Aktiengesellschaft, W. Ger., submitted by American Hoechst Corp., Somerville, NJ; CDL:097117-I)

### Page 29 of 50 107449 Knauf, W.; Schulze, E. (1976) HOE 23408 O H EH065 (Emulsifiable Concentrate): Effect on Cyprinus carpio (Carp): A08361. (Translation; unpublished study received May 26, 1978 under 8340-11; prepared by Hoechst AG, W. Ger., submitted by American Hoechst Corp., Somerville, NJ; CDL:097116-J)

107462 Knauf, W.; Emmel (1975) Effect of HOE 30418 O F AT001 (Active Ingredient) on Salmo Gairdneri (Rainbow Trout): Be richt-Nr. 39/75; A16364. (Translation; unpublished study received May 21, 1979 under 8F2085; prepared by Hoechst AG, W. Ger., submitted by American Hoechst Corp., Somerville, NJ; CDL:098297-O)

40746 Knauf, Schulze,; Ostmann, (1977) Hoe 23408 O H EF112 (Emulsifiable Concentrate 28) Effect on Salmo gairdneri~(Rainbow Trout): Report No. 37/77; A10230. (Translation from German; un- published study received Aug 11, 1977 under 8340-EX-1; prepared by Hoechst, AG, submitted by American Hoechst Corp., Somerville, N.J.; CDL:096310-U)

40747 Knauf, ; Schulze, ; Ostmann, (1977) Hoe 23408 O H EF112 (Emulsifiable Concentrate 28) Effect on Lepomis gibb osus (Blue Gill Sunfish): Report No. 36/77; A10228. (Translation from Germ an; unpublished study received Aug 11, 1977 under 8340-EX-1; pre- pared by Hoechst, AG, submitted by American Hoechst Corp., Somerville, N.J.; CDL:096310-V) Pumpkinseed sunfish

87813 Knauf, W.; Gorbach, S.; Kelbert, K. ; et al. (1977) Continuous-flow Study with Hoe 23408 OH on Bluegill (Lepomis gibbosus): Bericht-NR. 101/77; A11582. (Unpublished study received Dec 30, 1981 under 8340-11; prepared by Hoechst AG, West Germany, sub- mitted by Am erican Hoechst Corp., Somerville, N.J.; CDL: 246515-B)

38858 Reinert, H.K. (1975) Report--Static TLM 96 Hour Toxicity Study of Technical HOE-23408 in Bluegill Sunfish and in Rainbow Trout: Cannon Nos. 4E5198; 4E5199. (Unpublished study received Aug 22, 1975 under 6G1664; prepared by Cannon Laboratories, Inc., sub- mitted by American Hoechst Corp., Somerville, N.J.; CDL: 094682-G)

107459 Calmbacher, C. (1978) The Acute Toxicity of HOE23408 Technical to the Rainbow Trout Salmo gairdneri Richardson: UCES Proj. No. 11506-88-01; A13840. (Unpublished study received May 21, 1979 under 8F2085; prepared by Union Carbide Corp., sub- mitted by American Hoechst Corp., Somerville, NJ; CDL:098297-F)

107460 Calmbacher, C. (1978) The Acute Toxicity of HOE23408 Technical to the Bluegill Sunfish Lepomis macrochirus Ra finesque: UCES Proj. No. 11506-88-02; A13839. (Unpublished study received May 21, 1979 under 8F2085; prepared by Union Carbide Corp., submitted by American Hoechst Corp., Somerville, NJ; CDL:098297-H)

111960 or 76869 Fahmy, F. (1979) Toxicity Evaluation: T-3040; A16430. (Unpublished study received May 21, 1979 under 8F2085; pr epared by Canadian Hoechst Ltd., submitted by American Hoechst Corp., Somerville, NJ; CDL:098297-N)

111960 or
76869 Fahmy, F. (1979) Toxicity Evaluatio n:HOE-21079 , Free acid metabolite of Hoelon (98%) with Rainbow trout

. (Unpublished study received May 21, 1979 under 8F2085; prepared by Canadian Hoechst Ltd., submitted by American Hoechst Corp., Somerville, NJ; CDL:098297

133069 Reinert, H. (1975) Static TLM 96 Hour Toxicity Study of Technical Hoe-23403 in Bluegill Sunfish and in Rainbow Trout: Cannon # 4E-5198, 4E-5199. (Unpublished study received 1975 un der 6G1664; prepared by Cannon

### Page 30 of 50 Laboratories, Inc., submitted by American Hoechst Corp., Somerville, NJ; CDL:095400-F)

40074009 Drottar, K. (1986) Acute Toxicity of HOE 023408 5H EC32 A101 to Bluegill Sunfish (Lepomis macrochirus): ESE No. 86-350-0300- 2130. Unpublished study prepared by Environmental Science & Engineering, Inc. 42 p.

40074010 Ward, G. (1986) Acute Toxicity of HOE 203408 5H EC32 A101 to Rainbow Trout (Salmo gairdneri): ESE No. 86-350-0200-2130. Unpublished study prepared by Environmental Science & Engineering, Inc. 41 p.

40213509 Fischer, R. (1986) The Effect of Diclofop-methyl--Oil in Water Emulsion 369 (g/L)...to Salmo gairdneri (Rainbow Trout) in a Static-acute Toxicity Test...: Lab Project No. oek86-068e. Un- published study prepared by Hoechst AG. 21 p.

40213511 Surprenant, D. (1986) Acute Toxicity of Hoelon 3EW (HOE-023408 OH EW34 A204) to Bluegill (Lepomis macrochirus): Bionomics Report #BW-86=10-2163; Bionomics Study #1719.0986.6105.100. Unpublished study prepared by Springborn Bionomics, Inc. 20 p.

41573302 Franks, T.; Smith, G.; Wilson, R. (1990) Static Acute 96-Hour Toxicity of Diclofop-methyl (HOE 023408 00 ZD93 0002) to Rainbow Trout: Lab Project Number: A 42731: 89-0162. Unpublished study prepared by Battelle Columbus Div. 57 p.

41606301 Smith, G.; Schweitzer, M. (1990) Flow-through Acute 96-Hour Toxicity of Diclofop-methyl (...) to Bluegill Sunfish: Lab Project Number: SC900064. Unpublished study prepared by Battelle, Columbus Div. 61 p.

41606302 Smith, G.; Schweitzer, M. (1990) Flow-through Acute 96-Hour Toxicity of Diclofop-methyl (...) Emulsifiable Concentrate (3 EC Formulation) to Bluegill Sunfish: Lab Project Number: SC900065. Unpublished study prepared by Battelle, Columbus Div. 63 p.

41606303 Smith, G.; Schweitzer, M. (1990) Static Acute 96-Hour Toxicity of Diclofopmethyl (...) Emulsifiable Concentrate (3 EC Formula- tion) to Rainbow Trout: Lab Project Number: SC900066. Unpublished study prepared by Battelle, Columbus Div. 61 p.

92036010 Mayasich, J. (1990) Hoechst Celanese Corporation Phase 3 Summary of MRID 00107460. Diclofop-methyl Technical (Code: HOE 023408 OH ZD95 0003) Freshwater Acute Study: Bluegill Sunfis h. Prepared by UNI ON CARBIDE CORP. 13 p.

116622 or 40094602 Johnson, W.; Finley, M. (1980) Handbook of Acute Toxicity of Chemicals to Fish and Aquatic Invertebrates. By U.S. Fish and Wild- life Service, Columbia National Fisheries Research Laboratory. Washington, DC: USFWS. (Resource publication 137, pages 59,60 only; published study; CDL:248614-Q)

McCann, J.A. 1979. Beltsville Animal Biology Laboratory study # 2402 with Bluegill sunfish and technical grade Diclofop

McCann, J.A. 1979. Beltsville Animal Biology Laboratory study # 2402 with Rainbow trout and technical grade Diclofop

McCann, J.A. 1979. Beltsville Animal Biology Laboratory study # 2439 with Bluegill sunfish Methyl 2- 

### 4-(2,4-dich1orophenoxy)-phenoxy propanoate 

## 72-2 Acute Toxicity to Freshwater Invertebrates

MRID Citation Reference

### Page 31 of 50 107450 Knauf, W.; Schulze, E. (1977) HOE 23408 OH AT002 (Active Ingredient): Effect on Daphnia magna (Water Flea): A10637. (Translation of document no. A08777; unpublished study received May 26, 1978 under 8340-11; prepared by Hoechst Aktiengesellschaft, W. Ger., submitted by American Hoechst Corp., Somerville, NJ; CDL: 097116-K)

107451 Knauf, W. (1976) HOE 23408 O H EH065 (Emulsifiable Conc.): Effect on Daphnia magna: AO9916. (Translation of document no. A07881; unpublished study received May 26, 1978 under 8340-11; prepared by Hoechst Aktiengesellschaft, W. Ger., submitted by American Hoechst Corp., Somerville, NJ; CDL:097116-L)

107461 Knauf, W.; Schulze, E. (1979) Effect of HOE 23408 OH EH065 (Emulsifiable Concentrate) on Daphnia magna (Water Flea): Bericht- Nr. 21/79; A16955. (Unpublished study received May 21, 1979 under 8F2085; prepared by Hoechst AG, W. Ger., submitted by American Hoechst Corp., Somerville, NJ; CDL:098297-L)

40074011 Ward, G. (1986) Acute Toxicity of HOE 023408 5H EC32 A101 to Water- fleas (Daphnia magna): ESE No. 86-350-0100-2130. Unpublished study prepared by Environmental Sciences & Engineering Inc. 36 p.

40213510 Fischer, R. (1986) The Effect of Diclofop-methyl--Oil in Water Emulsion 369 (g/L)...to Daphnia magna (Waterflea) in a Static- acute Toxicity Test...: Lab Project No.: oek86-069e. Unpublished study prepared by Hoechst AG. 22 p.

41573303 Franks, T.; Smith, G.; Switzer, K.; et al. (1989) Static Acute 48- Hour Toxicity of Diclofop-methyl (HOE 023408 00 ZD93 0002) to Daphnia magna: Lab Project Number: A/42732: SC890024. Unpublished study prepared by Battelle Columbus Div. 57 p.

41606304 Smith, G.; Schweitzer, M. (1990) Static Acute 48-Hour Toxicity of Diclofop-methyl (...) Emulsifiable Concentrate (3 EC Formulation) to Daphnia magna: Lab Project Number: SC900067. Unpublished study prepared by Battelle, Columbus Div. 67 p.

McCann, J.A. 1979. Beltsville Animal Biology Laboratory study # 2404 with Daphnia magna and technical grade Diclofop 

## 72-3 Acute Toxicity to Estuarine/Marine Organisms

MRID Citation Reference

71388 or
76865 Heitmuller, T.; Maziarz, T. (1981) Acut e Toxicity of Hoelon(R)I (HOE-23408) to Eastern Oysters (Crassostr ea virginica): Re- port No

. BP-81-2-21

. (Unpublished study received Mar 2, 1981 under 83 40-11; prepared by EG & G, Bionomics, submitted by Amer- ican Hoechst Corp., Somerville, N.J.; CDL:244465-C)

76863 Heitmuller, T.; Maziarz, T. (1981) Acute Toxicity of Hoelon(R)I (HOE-23408) to Eastern Oysters (Crassostrea virgin ica): Re- port No. BP-81-2-21-R

. Rev. (Unpublished study received Nov 21, 1981 under 8340-11; prepared by EG & G Bionomics, submitted by American Hoechst Corp., Somerville, N.J.; CDL:245123-C)

76864 Heitmuller, T.; Maziarz, T. (1981) Acute Toxicity of HOE-21079 to Eastern Oysters (Crassostrea virginica): Report No. BP-81- 3- 22. (Unpublished st udy received May 21, 1981 under 8340-11; prepared by EG & G Bionomics, submitted by American Hoechst Corp., Somerville, N.J.; CDL:245123-D)

76865 Hollister, T.A.; Maziarz, T.P. (1981) Acute Toxicity of Hoelon (R)I (HOE-23408) to Embryos-larvae of Eastern Oysters (Crassostrea virginica): Report No. BP-81-4-51-R.

### Page 32 of 50 Rev. (Unpublished study recei ved May 21, 1981 under 8340 -11; prepared by EG & G Bionomics, submitted by American Hoechst Corp., Somerville, N.J.; CDL:245123-E)

76866 Hollister, T.A.; Maziarz, T.P. (1981) Acute Toxicity of Hoe-21079 to Embryos-larvae of Eastern Oysters (Crassostrea virginica): Report No. BP-81-5-71. (Unpublished study received May 21, 1981 under 8340-11; prepared by EG & G Bionomics, submitted by American Hoechst Corp., Somerville, N.J.; CDL:245123-F) 

## 72-4 Fish Early Life Stage /Aquatic Invertebrate Life Cycle Study

MRID Citation Reference

71386 EG & G, Bionomics (1978) Methods for Conducting Early Life Stage Toxicity Tests with Fathead Minnow (Pimephales promelas). (Unpublished study, including submitter summary, received Mar 2, 1981 under 8340-11; submitted by American Hoechst Corp., Somerville, N.J.; CDL:244464-H)

97836 Wilson, Brenda. 1981. The toxicity of Hoelon to Rainbow Trout (Salmo gairdneri) Embryos and Lanrae. An unpublished report prepared by E. G. & G. Bionanics Aquatic Toxicology Laboratory for American Hoechst Corporation. ACC# 246021



### .
76867 LeBlanc, G.A.; Mastone, J.D.; Wilson, B.F. (1981) The Toxicity of Hoelon(R)I to Fathead Minnow (Pimephales promelas) Embryos and Larvae: Report #BW-81-4- 853. (Unpublished study receive d May 21, 1981 u nder 8340-11; prep ared by EG & G Bionomics, sub- mitted by American Hoec hst Corp., Somerville, N.J.; CDL: 245123- G)

41737902 Smith, G. (1990) Static-Renewal Chronic 21-Day Toxicity of Diclofop-methyl to Daphnia magna: Lab Project Number: SC900115: 90-0107. Unpublished study prepared by Battelle Columbus Div. 8 p.

92036011 Mayasich, J. (1990) Hoechst Celanese Corporation Phase 3 Summary of MRID 00076867. Diclofop-methyl Technical (Code: HOE 023408 OH ZD95 0003) Fish Early Life Cycle Study: Fathead Minnow. Prepared by EG & G, BIONOMICS. 14 p.

71385 EG & G, Bionomics (1980) Methods for Conducting Early Life Stage Toxicity Tests with Rainbow Trout (Salmo gairdneri). (U n- published study, including submitter summary, received Mar 2, 1981 under 8340-11; submitte d by American Hoechst Corp., Somer- ville, N.J.; CDL:244464-G)

84653 Dorr, V.A. (1981) Summary: (Exposure of Rainbow Trout Embryos and Larvae to Hoelon). Summary of studies 246021-E and 246021-F

. (Unpublished study received Oct 7, 1981 under 8340-11; submitted by Am erican Hoechst Corp., Somerville, N.J.; CDL:246021-D)

97836 LeBlanc, G.A.; Mastone, J.D.; Wilson, B.F. (1981) The Toxicity of Hoelon(R) to Rainbow Trout (Salmo gairdneri) Embryos and Larvae: Report #BW-81-6-929. (Unpublished study received Oct 7,1981 under 8340-11; prep ared by EG & G Bionomics, submitted by American Hoechst Corp., Somerville, N.J.; CDL:246021-E) 

## 72-5 Life cycle fish

MRID Citation Reference

43284601 Dionne, E. (1994) Diclofop-methyl: The Chronic Toxicity to the Fathead Minnow (Pimephales promelas) During a Full Life-cycle Exposure: Lab Project Number:

### Page 33 of 50 1719.0692.6199.122: 94-3-5180. Unpublished study prepared by Springborn Labs, Inc. 705 p. 

## 72-6 Aquatic org. accumulation

MRID Citation Reference

41996903 Gildemeister, H. (1991) Hoe 023408-Carbon 14: Flow-Through Bioaccumulation and Metabolism Study with Bluegill Sunfish (Lepomis macrochirus). Unpublished study prepared by Hoechst Aktiengese- llschaft. 57 p.

84654 Cubbedge, S.D. (1981) Analysis of HOE 23408 and HOE 35449 in Rainbow Trout: PL No. 81PL-624-1. (Unpublished study, including letter dated Jul 30, 1981 from S.D. Cubbedge to Hanson H. North, received Oc t 7, 1981 under 8340-11; prepared by Biospherics, Inc., submitted by Amer ican Hoechst Corp., Somerville, N.J.; CDL:246021-F) 

## 72-7 Aquatic Field Study

N.R. Mayland, P.G. 1979. Aquatic study conducted under Field Conditions in Minnesota (06-MN-79-019)

45695 Kleis, M.M.; Spencer, W.T.; Mayland, P.G. (1980) Hoelon(R)I 3EC Herbicide Fish Monitoring Studies: North Dakota Test # 06-ND-79- 018; Montana Test # 13-MT-79- 100. (Unpublished study received Aug 21, 1980 under 8340-1 1; prepared in cooperation with Biospherics, Inc., submitted by American Hoechst Corp., Somerville, N.J.; CDL:243097-B)

N.R. Grande, John A. 1980 Pond study in Virginia

134716 American Hoechst Corp. (1979) North Dakota Fish Monitoring Study. (Unpublished study received Sep 25, 1979 unde r 8340-EX-1; CDL: 098988-B)

134717 American Hoechst Corp. (1979) Montana Fish Monitoring Study. (Unpublished study received Sep 25, 1979 under 8 340-Ex-1; CDL: 098988-C)

N.R. 

### The behaviour of the plant protection agent HOE 23408 Oil in an open-air pond


## 122-1 Seed Germination/S eedline Emergence a nd Vegetable Vigor

MRID Citation Reference

41606305 Chetram, R. (1990) Tier 2 Vegetative Vigor Nontarget Phytotoxicity Study using Technical Diclofop-methyl: Lab Project Number: LR89- 42A: 89-0148. Unpublished study prepared by Pan-Agricultural Laboratories, Inc. 138 p.

41606306 Chetram, R. (1990) Tier 2 Seed Germination/Seedling Emergence Nontarget Phytotoxicity Study using Technical Diclofop-methyl: Project Number: LR89-42B; 89-0147. Unpublished study prepared by Pan-Agricultural Laboratories, Inc. 183 p. 

## 123-2 Aquatic plant growth

MRID Citation Reference

45541703 Sowig, P. (2001) Duckweed (Lemna gibba G3) Growth Inhibition Test DiclofopMethyl Substance, Technical 94.4%: Lab Project Number: CE00/010: C008630. Unpublished study prepared by Aventis CropScience Gmbh. 60 p. 

# Non Guideline Selections

### Page 34 of 50 MRID Citation Reference

84656 Cubbedge, S.D. (1981) Analysis of HOE 23408 and HOE 35449 in Rainbow Trout, Mud Puppies, Buffer Plants and Pond Water: PL No. 81PL-487-2. (Unpublished study, including letter dated Jul 7, 1981 from G. Milad to Hanson H. North, prepared by Bio- spherics, Inc., submitted by American Hoechst Corp., Somerville, N.J.; CDL:246021-H)

87812 Gorbach, S.; Kunzler, K.; Knauf, W.; et al. (1977) Uptake of Hoe 23408 OH Residues from a Water-soil System by Catfish (Ictalurus nebulosus) and Dissipation of the Taken Up Residues in Fresh Water: Bericht-Nr. Fo.Ber. 281/77; A11571. (Unpublished study received Dec 30, 1981 u nder 8340-11; prepared by Hoechst AG, West Germany, submitted by American Hoechst Corp., Somerville, N.J.; CDL:246515-A)

40074008 Graney, R. (1986) Summary of Aquatic Toxicity of One Shot Herbicide. Unpublished summary prepared by Ameri can Hoechst Corp. 4 p.

40213508 Graney, R. (1986) Aquatic Toxicology Testing of Hoelon 3EW: Sum- mary. Unpublished compilation prepared by Hoechst-Roussel Agri-Vet Co. 5 p.

48033006 Jiao, B.; Yeung, E.; Chan, C.; et al . (2008) Establishment of a Transgenic Yeast Screening System for Estrogenicity and Id entification of the Anti-Estrogenic Activity of Malachite Green. Journal of Cellular Biochemistry 105: 1399-1409.

48033008 Kojima, H.; Katsura, E.; Takeuchi, S.; et al. (2004) Screening for Estrogen and Androgen Receptor Activities in 200 Pesticid es by In Vitro Reporter Gene Assays Using Chinese Hamster Ovary Cells. Environm ental Health Perspectives 112(5): 524-
531.

41208201 Krebs, B.; Heinen, B. (1989) HOE 023408 (Diclofop-methyl): Calculation of the Expected Residue Concentration on wheat and Barley Plants at the Day of Application: Project ID OE 099/89. Unpublished study prepared by Hoechst Aktiengesellschaft.



## Fate/Chemistry Bibliography

161-1 Hydrolysis

MRID Citation Reference

71389 Asshauer, J.; Klockner, C.; Thier, W. (1980) Abiotic Hydrolysis of HOE 23408: Fo. Ber. 310/80; A20914. (Unpublished study received Mar 2, 198 1 under 8340-11; prepared by Hoechst, AG, W. Germany, submitted by American Hoechst Corp., Somerville, N.J.; CDL:244465-D)

41573309 Gorlitz, G. (1990) HOE 023408, Diclofop-m ethyl Abiotic Hydrolysis as a Function of pH: Lab Project Number: A 42623: CP035/88. Un- published study prepared by Hoechst Ag. 37 p.

ACC 097120 Hydrolysis of HOE-23408 Document Number A09903 Acc. No. I 097120, Sect. J, Vol. 17, Part 3 5-44 

## 161-2 Photodegradation-water

MRID Citation Reference

### Page 35 of 50 41573307 Gildemeister, H. (1990) HOE 023408-carbon 14, Photodegradation in Water: Lab Project Number: A 43058: CB89/160. Unpublished study prepared by Hoechst Ag. 61 p.

107471 Thier, W.; Fischer, H. (1979) Photolytic Degradation of the Herbicide HOE 23408 in Aqueous Solution under Simulated Sunli ght: A17429. (Unpublished study received Jun 27, 1979 under 8F2085; prepared by Hoechst AG, W. Ger., subm itted by American Hoechst Corp., Somerville, NJ; CDL:098356-H) 

## 161-3 Photodegradation-soil

MRID Citation Reference

87811 American Hoechst Corporation (1981)Residues of Hoe 23408, Hoe 21079 and Hoe 30418 in Soil|. (Compilation; unpublished study received D ec 30, 1981 under 834 0-11; CDL: 246516-D)

107470 Thier, W.; Fischer, H. (1979) Photolytic Degradation of the Herbicide HOE 23408 on Soil Covered Thin-layer Slides under Simula ted Sunlight: A17424. (Unpublished study r eceived Jun 27, 1979 under 8F2085; prepared by Hoechst AG, W. Ger., submitted by American Hoechst Corp., Somerville, NJ; CDL:098356-G)

41573308 Gildemeister, H. (199 0) HOE 023408-carbon 14: Photodegradation on Soil: Lab Project Number: CB89/161: A 42994. Unpublished study prepared by Hoechst Ag. 49 p.


## 162-1 Aerobic soil metabolism

MRID Citation Reference

41573310 Speer, M. (1989) Diclofop-methyl: Aerobic Degradation and Metabolism in Four Soils at Two Temperatures and with two Different Moisture Contents: Lab Project Number: HOE/01/003: A/42498. Un- published study prepared by Fraunhofer-Institut Fur Umweltchemie und Okotoxikologie. 87 p.

38861 Hoechst, Aktiengesellschaft (1975) Behaviour of the Plant Protective Active Ingredient in Soil: Report No. (B)40/75; AO 3687. (Translation; unpublished study received Aug 22, 1975 under 6G1664; submitted by American Hoechst Co rp., Somerville, N.J.; CDL:094682-J)

87826 Martens, R. (1978) Degradation of the herbicide 14 C-diclofop-methyl in soil under different conditions. Pesticide Science 9:12 7-134. (Also In unpublished s ubmission received Dec 30, 1981 under 8340-11; submitted by American Hoechst Corp., Somerville, N.J.; CDL:246514-E)


## 162-2 Anaerobic soil metabolism

MRID Citation Reference

ACC 97118 Degradation of Herbicide HOE-23408 OH in the Soil under Anaerobic Conditions. Document A0- 63 16, Acc. No. 097118, Section J, part l of 3, Vol. 15 of 17 J-3. 

## 162-3 Anaerobic aquatic metabolism

MRID Citation Reference

40806307 Ellgehausen, H. (1986) Degradation of Diclofop-methyl (HOE 023408) in an Anaerobic Aquatic System: Project ID. 056654. Unpublished study prepared by Research Consulting Co. 43 p.

42734201 Reynolds, J. (1993) Anaerobic Aquatic Metabolism of (carbon 14)-Diclofop-Methyl: Lab Project Number: RPT00120: XBL 91062. Unpublished study prepared by XenoBiotic Labs, Inc. 96 p.

### Page 36 of 50 87826 Martens, R. (1978) Degradation of the herbicide 14 C-diclofop-methyl in soil under different conditions. Pesticide Science 9:12 7-134. (Also In unpublished s ubmission received Dec 30, 1981 under 8340-11; submitted by American Hoechst Corp., Somerville, N.J.; CDL:246514-E) 

## 162-4 Aerobic Aquatic Metabolism

MRID Citation Reference

(none) 

## 163-1 Leach/adsorp/desorption

MRID Citation Reference

40520301 Gilder meister, H. (1986) HOE 023408--(Carbon 14) (Diclofop-meth yl-- (Carbon 14): Leaching Study: Laboratory Project ID CB016/85. Unpublished study prepared by Hoechst Celanese Corp. 27. p.

40806308 Goerlitz, G.; Eyrich, U. (1987) Diclofop-methyl (HOE 023408) - Adsorption/Desorption in the System Soil/Water: Project ID. A37726. Unpublished study prepared by Hoechst AG. 72 p.

42347801 Reynolds, J. (1992) Adsorption and Desorption of 14 C-Diclofop-methyl in Four Soils: Lab Project Number: XBL 92021: RPT0092. Unpublished study prepared by XenoBiotic Laboratories, Inc. 116 p. 

## 164-1 Terrestrial field dissipation

MRID Citation Reference

40520302 Graney, R. (1988) Response to EPA's Review of the Hoelon Field Dissipation Study Conducted in Salisbury, MD 1985 ...: Laboratory Project ID EH-84-USA-40R. Unpublished study prepared by Hoechst Celanese Corporation. 45 p.

40806309 Dorn (1988) Reanalyses of HOE 023408 and its Free Acid in Selected Soil Samples of the Field Dissipation Study EH USA 40R with an Improved Analytical Method: Project ID. A38541. Unpublished study prepared by Hoechst AG. 37 p.

42252101 Hey, M.; Czarnecki, J.; Miller, M. (1992) Determination of the Combined Residues of Diclofopmethyl and its Metabolite Diclofop (Free Acid) in Soil: Lab Project Number: 1127: 1157. Unpublished study prepared by Colorado Analy tical Research and Development Corp. and PanAgricultural Laboratories, Inc. 557 p.

87824 Smith, A.E. (1979) Extraction of free and bound carboxylic acid residues from field soils treated with the herbicides benzoyl-prop-ethyl, diclofop-methyl, and flamprop-methyl. Journal of Agricultural and Food Chemistr y 27(2):428-432. (Also In unp ublished submission received Dec 30, 1981 under 8340-11; submitted by American Hoechst Corp., Somerville, N.J.; CDL:246514- C)

87825 Smith, A.E. (1976) Use of acetonitrile for the extraction of herbicide residues from soils. Journal of Chromatography 129:309- 314. (Also in unpublished su bmission received Dec 30, 1981 under 8340-11; submitted by American Hoechst Corp., Somerville, N.J.; CDL:246514-D)

87828 Smith, A.E. (1979) Transformation of 14 C-diclofop-methyl in small field plots. Journal of Agricultural and Food Chemistr y 27(6):1145-1148. (A lso In unpublished submission received Dec 30, 1981 under 8340-11; submitted by American Hoechst Corp., Somerville, N.J.; CDL:246514-G)

156479 Johnson, J. (1985) Analytical Report: Analyses of Hoelon Residues in Soil from Salisbury, Maryland: Experiment No.: EH-84-USA-40R. Unpublished compilation prepared by American Hoechst Corp. 709 p.

### Page 37 of 50 

## 164-2 Aquatic Field Dissipation

MRID Citation Reference

45695 American Hoechst Corporation (1980) Hoelon® 3EC Pond Monitoring Studies in North Dakota, Minnesota, and Montana. Summary of studies 243 097-A and 243097-B . (Unpublished study received Aug 21, 1980 under 8340-11; CDL:243097-D)
45696 Grande, J.A.; Diaz, R.J. (1980) Pond St udy in Virginia. (Unpublished study received Aug 21, 1980 under 8340-11; submitted by American Hoec hst Corp., Somerville, N.J.; CDL:243097-C) 45697 American Hoechst Corporation (1980) Hoelon® 3EC Pond Monitoring Studies in North Dakota, Minnesota, and Montana. Summary of studies 243 097-A and 243097-B . (Unpublished study received Aug 21, 1980 under 8340-11; CDL:243097-D) 84656 Cubbedge, S.D. (1981) Analysis of HOE 23408 and HOE 35449 in Rainbow Trout, Mud Puppies, Buffer Plants and Pond Water: PL No. 81PL-487-2. (Unpublished study, including letter dated Jul 7, 1981 from G. Milad to Hanson H. North, prep ared by Biospherics, Inc., submitted by American Hoechst Corp., Somerville, N.J.; CDL:246021-H) 87808 Cubbedge, S.D.; Grande, J. (1981) Analysis for Residues of HOE 23408 and HOE 35449 in Pond Samples: Virginia Pond Study: PL No. 80PL-185 7-3-4. Rev. (Unpublishe d study received Dec 30, 1981 under 8340-11; prepared by Biospherics, Inc., submitted by American Hoechst Corp., Somerville, N.J.; CDL:246516-A; 246515) 87837 Ass|hauer, J.; Fischer, H.; Knauf, W.; et al. (1976) Behavior of the Plant Protection Agent Hoe 23408 OH in an Open-air Pond: Bericht-Nr. Fo.Ber. 265/76; A07351. (Translation; unpublished study received Dec 30, 1981 under 8340 -11; prepared by Hoechst AG, West Germany, submitted by American Hoechst Corp., Somerville, N.J.; CDL:246514-P)

134716 American Hoechst Co rp. (1979) North Dakota Fish Monitoring Study. (Unpublished study received Sep 25, 1979 under 8340-EX-1; CDL: 098988-B)

134717 American Hoechst Co rp. (1979) Montana Fish Monitoring Study. (Un- p ublished study received Sep 25, 1979 under 8340-Ex-1; CDL: 098988-C) 

## 165-4 Bioaccumulation in fish

MRID Citation Reference

41996903 Gildemeister, H. (1991) Hoe 023408-Carbon 14: Flow-Through Bioaccumulation and Metabolism Study with Bluegill Sunfish (Lepomis macrochi rus). Unpublished study prepared by Hoechst Aktiengese-llschaft. 57 p.

45878201 Madsen, T.; Leak, T.; Meyer, B. (2003) Bi oconcentration and Metabolis m of (Dichlorophenyl-U- (Carbon 14))-Diclofop-Methyl in Bluegill, Le pomis macrochirus: Lab Project Number: 46910: 601BL. Unpublished study prepared by ABC Laboratories, Inc. 139 p.

84654 Cubbedge, S.D. (1981) Analysis of HOE 23408 and HOE 35449 in Rainbow Trout: PL No. 81PL624-1. (Unpublished study, including letter dated Ju l 30, 1981 from S.D. Cubbedge to Hanson H. North, received Oct 7, 1981 under 8340-11; prepar ed by Biospherics, Inc. , submitted by American Hoechst Corp., Somerville, N.J.; CDL:246021-F)

87812 Gorbach, S.; Kunzler, K.; Knauf, W.; et al. (1977) Uptake of Hoe 23408 OH Residues from a Water-soil System by Catfish (Ictalurus nebulosus) and Dissipation of the Taken Up Residues in Fresh Water: Bericht-Nr. Fo.Ber. 281/77; A11571. (Unpublished study received Dec 30, 1981 under 8340-11; prepared by Hoechst AG, West Germany, submitted by American Hoechst Corp., Somerville, N.J.; CDL:246515-A) 

## 166-1 Ground water-small prospective

MRID Citation Reference

### Page 38 of 50 41220701 Chang, H. (1989) Phase I - Site Selection an d Characterization Assessm ent of Diclofop-methyl Leaching Potential: Small Scale Pr ospective Groundwater Monitoring Study: Proj. ID 3/88-HRA.1. Unpublished study prepared by Twin City Testing Corp. 114 p.

41367601 Chang, H. (1990) Phase I - Site Selection and Characterization Assessment of Diclofop-methyl Leaching Potential: Small Scale Pros pective Groundwater M onitoring Study: Field Infiltration Test & Grain Size Analysis: Supplemen t to Phase I...: Lab Project 88-HRA-001-B; 88-0086; 3/88- HRA.1. Unpublished study pre- pared by Twin City Testing Corp. 36 p.

43860301 Bregger, T.; Holden, R.; Witkin, D. (1995) Small-Scale Prospective Groundwater Monitoring Study for Diclofop-Methyl (Hoelon 3EC): First Progress Report: Lab Project Number: BL-94R-01. Unpublished study prepared by Agvise Labs; Quanterra Environmental Services; and Waterborne Environmental, Inc. 25 p.

43956801 Bregger, T.; Holden, P. (1996) Small-Scale Prospective Groundwater Monitoring Study for Diclofop-Methyl (Hoelon 3EC): (Second Progress Report): Lab Project Number: A 55773: 622.02: BL-94R-01. Unpublished study prepared by Waterborne Environmental, Inc.; Agvise Labs; and Quanterra Environmental Services. 20 p.

44088301 Bregger, T.; Holden, P. (1996) Small-Scale Prospective Groundwater Monitoring Study forDiclofop-methyl (Hoelon 3EC): (Third Progress Report): Lab Project Number: A 55819: BL-94R01: 622.02. Unpublished study prepared by Waterborne Environmental, Inc.; AgrEvo USA Co.; and Agvise Labs. 81 p.

44158301 Kelly, I. (1996) Prospective Groundwater Monitoring Study for Diclofop-methyl (Hoelon 3EC): Supplement: Lab Project Number: A 55819. Unpublished study prepared by Waterborne Environmental, Inc.; Agvise Labs; and Quanterra Environmental Services. 55 p.

44247801 Kelly, I.; Kelley, K. (1997) Small-Scale Prospective Ground-Water Monitoring Study for DiclofopMethyl (Hoelon 3EC): Fourth Progress Report: Lab Project Number: A 57721: BL-94R-01: 622.02. Unpublished study prepared by AgrEvo USA Co.; Agvise Laboratories; and Quanterra Environmental Services. 102 p.

44532501 Kelly, I.; Singer, S.; Johnson, L. et al. (1998) A Small-Scale Prospective Ground-Water Monitoring Study for Diclofop-Methyl (Hoelon 3EC): Final Report: Lab Project Number: BL-94R-01: A59908: 622.02. Unpublished study prepared by Waterborne Environmental, Inc., Agvise Labs., Inc. and AgrEvo USA Co. 424 p.

### Page 39 of 50 

# APPENDIX B: ECOLOGICAL TOXICITY DATA

Toxicity to Terrestrial Animals

Birds, Acute and Subacute

The following are results for the acute oral toxi city testing with an upland game bird using technical grade diclofop-methyl. Since the LD 50 

### obtained in both studi es exceeds 2000 mg/kg, diclofop-methyl is categorized prac tically nontoxic to avian species on an acute oral basis. The guideline requirement for this test (71-1) is fulfilled by MRID 40072903.

Acute Oral Toxicity to birds.

Species % ai LD 50 (mg/kg) Toxicity Category MRID No.

Author/Year Study

Classification 1

Northern bobwhite quail (Colinus virginianus) 94.5 >2250 Practically nontoxic 40072903

Hinken et al.

, 1986 Core

Northern bobwhite quail (Colinus virginianus) 95 4,400 Practically nontoxic Acc. No. 097117

1977 Supplemental

1 “Core” indicates the study satisfies the guideline; “supplementa l” indicates the study is scientifically sound, but does not s atisfy the guideline.



### The following are results of subacute dietary test ing with an upland game bird (the northern bobwhite) and a waterfowl (the ma llard) using technica l grade diclofop-methyl. Since all of the
LC 50 

### 's exceed 5000 ppm, diclofop-methyl is categor ized as practically nontoxic to birds on a subacute dietary basis. The test guideline requirement (71-2) is fulfilled by MRID 40072901 and 40072902, and Acc. No. 097291.

Subacute dietary toxicity to birds.

Species % ai 5-Day LC 50 (ppm) 1 Toxicity Category MRID No.

Author/Year Study

Classification

Northern bobwhite (Colinus virginianus) 95 13,000 Practically nontoxic Acc. No. 097117 Roberts,1977 Core

Northern bobwhite (Colinus virginianus) 94.5 >5620 Practically nontoxic 40072901

Hinken et al.

, 1986 Core

Mallard (Anas platyrhynchos) 95 >20,000 Practically nontoxic Acc. No. 097291 Core

Mallard ( Anas platyrhynchos ) 94.5 >5620 Practically nontoxic 40072902

Hinken et al.

, 1986 Core

Coturnix quail ( Coturnix coturnix japonica ) 95 >20,000 Practically nontoxic Acc. No. 094682 Terrell & Parke,

1975 Supplemental

1 Test organisms observed an additiona l three days while on untreated feed.

### Page 40 of 50 

### Birds, Chronic

The following are results of avian reproductive studi es with technical grade active ingredient. The studies found no significant effect of repr oduction or parental toxicity at dietary concentrations up to 200 ppm. The studies are supplemental because the test levels were not high enough to determine the NOAEL and LOAEL, and the highest test concentration was less than the maximum expected environmental concen tration (EEC). With a maximum application rate of 1 lb AI/A, the maximum EEC is 240 ppm. Because the available data is sufficient to
conclude a low risk of chronic effects to bi rds, a request to waiv er new avian reproduction studies to fulfill this guideline has b een approved by EFED (Bar Code #D261423).

Avian reproduction toxicity

Species/ Study Duration % ai NOAEL (ppm) LOAEL (ppm) LOAEL Endpoints MRID No.

Author/Year Study Classification

Northern bobwhite (Colinus virginianus) 94.5 200 Not

determined None Acc. No. 098297 and

243472 Supplemental

Mallard (Anas platyrhynchos) 94.5 200 Not

determined None Acc. No. 098297 and

243472 Supplemental



### Mammals, Acute and Chronic

Wild mammal testing is not required for diclofop- methyl because rat toxicity test submitted to the Agency's Health Effects Division (HED) provide adequate information on toxicity to mammals. Table 4-eco gives acute rat toxicity values for technical diclofop-methyl and a formulated product. The geometric mean of the LD 50 

### for male and female rats is 568 mg ai/kg. This indicates that diclofop-methyl is moderately toxic to small mammals on an acute oral basis.

Acute Toxicity to Mammals

Species % ai Test type LD 50 (mg/kg) MRID/Acc. No.

Rat ( Rattus norvegicus ) “Technical” Acute oral 580 (male) 557 (female) 097107

Rat ( Rattus norvegicus ) 36% Acute oral 2029 (male) (730 mg ai/kg)

Rat ( Rattus norvegicus ) “Technical” Acute dermal > 5000

### Page 41 of 50 

### A limited amount of information on the subchron ic toxicity of diclofop acid, the primary degradation product of diclofop-me thyl, is provided by a subchr onic study with the rat (MRID not listed). This study found th at a dietary concentration of 500 ppm of diclofop acid caused increased kidney weight in males. The NOAEL was 100 ppm. For comparison, a 30-day feeding study with the rat testing diclofop-methyl found incr eased organ weights in males at a dietary concentration of 80 ppm. This study did not determine the NOAEL. These results indicate that diclofop acid is less toxic to mammals than is the parent compound, diclofopmethyl.

The following are the results of some chroni c and subchronic mammalian studies that are pertinent to ecological effects. Based on these results, the NOAEL and LOAEL for ecologically significant effects in mammals are establishe d at 30 ppm and 100 ppm, respectively, based on pup mortality observed in the 3-gene ration reproduction test. It is noteworthy that a short-term (15-week) developmental study showed fetotoxi c effects with an or al dose of 32 mg/kg body weight, which is approximately equivalent to an dietary dose of 640 ppm. This indicates that short-term exposure to diclofop-methyl can impair reproduction of mammals, although somewhat higher doses are required than for long-term exposures.

Subchronic and Chronic Toxicity to Mammals

Species % ai Test Type Toxicity Value Affected Endpoints MRID/Acc. No.

Rat ( Rattus norvegicus ) 98 3 generation reproduction NOAEL=30 ppm LOAEL=100 ppm Increased pup mortality 097111

Rat ( Rattus norvegicus ) “Tech.” Developmental Teratogenicity: NOAEL>100 mg/kg (2000 ppm)

Fetotoxic: NOAEL=10 mg/kg (200 ppm) LOAEL=32 mg/kg (640 ppm)

Maternal: NOAEL<10 mg/kg (200 ppm) Teratogenic:

none

Fetotoxic: reduced body weight gain, increased resorptions, dilation of renal pelvis,

distention of uterus.

Maternal: increased liver weight 097108



### Insects

A honey bee acute toxicity study (Guideline No. 141- 1) is required for diclofop-methyl because Diclofop-methyl is a systemic herb icide and could pose risk to bees . Its use sites (wheat, barley, and turf) and applicatio n methods may result in exposure to honey bees.

Toxicity to Freshwater Aquatic Animals

Freshwater Fish, Acute

The following are the results of acute toxicity tes ting with freshwater fish using technical grade diclofop-methyl and a formulated product. The LC 50 

### values for both a coldwater test species (the rainbow trout) and a warmwater te st species (the bluegill sunfish) falls in the range of 0.1 to 1

### Page 42 of 50 

### ppm, classifying diclofop-methyl as highly toxic to freshwater fish on an acute basis. The test guideline requirement (72-1) is fulf illed by MRIDs 41573302 and 41606301, and Acc. No. 098297 for the TGAI (72-1(a) and 72-1 (c)) and by MRIDs 41606302 and 41606303 for the formulated product.

Acute toxicity to freshwater fish

Species, Study type % AI 96-hour

LC 50 (ppm) Toxicity Category MRID No.

Author/Year Study

Classification

Rainbow trout (Oncorhynchus mykiss)

static 95.1 0.23 Highly toxic 41573302

Frank et al. , 1990 Core

Rainbow trout (Oncorhynchus mykiss) “Technical” 0.54 Highly toxic USEPA, 1979 Core

Rainbow trout (Oncorhynchus mykiss),

static 95 0.25 Highly toxic USFWS, 1978 Core

Rainbow trout (Oncorhynchus mykiss) 95 0.17 Highly toxic Acc. No. 094682 Reinert & Roger,

1975 Supplemental

Rainbow trout (Oncorhynchus mykiss) “Technical” 0.32 Highly toxic Acc. No. 098297 Core

Rainbow trout (Oncorhynchus mykiss),

static 34.8 (3 EC) 0.65 (formulation) 0.22 (AI) Highly toxic 41606303

Smith & Schweitzer, 1990 Core

Bluegill sunfish (Lepomis macrochirus) 95.1 0.15 Highly toxic 41606301

Smith & Schweitzer, 1990 Core

Bluegill sunfish (Lepomis macrochirus) Technical 0.31 Highly toxic USEPA, 1979 Core

Bluegill sunfish (Lepomis macrochirus) 95 0.54 Highly toxic USFWS, 1978 Core

Bluegill sunfish (Lepomis macrochirus) 95 0.29 Highly toxic Acc. No. 094682 Reinert & Roger,

1975 Supplemental

Bluegill sunfish (Lepomis macrochirus) Technical 0.24 Highly toxic 098297 Supplemental

Bluegill sunfish (Lepomis macrochirus) 34.8 (3 EC) 0.36 (formulation) 0.13 (AI) Highly toxic 41606302

Smith & Schweitzer, 1990 Core



### A study with the rainbow trout provides inform ation on the free acid metabolite of diclofopmethyl. The 96-hr LC 50 

### was determined to be 21.9 pp m (19.3-24.9) with an NOAEC of 13.5 ppm. This indicates that the acid metabolite of diclofop-methyl is less toxic to fish than the parent by almost two orders of magnitude (Acc. No. 098297).

### Page 43 of 50 

### Freshwater Fish, Chronic

The following are the results of chronic toxicity testing with freshwater fish using technical grade diclofop-methyl. The results of two ear ly life-stage toxicity tests indicate that concentrations of 46 ppb or greate r are detrimental to the survival of immature fish. The lifecycle toxicity test indica tes that exposure throughout a fish’s li fe-cycle will impairment of larval growth at concentrations of 15 ppb or greater. The NOAEC for the most sensitive chronic endpoint was established at 7.5 ppb. The test guide line requirement for early life-stage testing (72-4) has been fulfilled by MRID 00076867 and A cc. No. 246021, and that for life-cycle testing (72-5) has been fulfilled by MRID 43284601.

Chronic toxicity to freshwater fish

Species, Study duration % ai NOAEC (ppb) LOAEC (ppb) MATC 1 (ppb) Endpoints

Affected MRID No.

Author/Year Study

Classification

Early Life-Stage Toxicity Test

Fathead minnow ( Pimephales promelas ) 93 39 86 58 Survival, percent

hatch MRID 00076867 Wilson, 1981 Core

Rainbow trout (Oncorhynchus mykiss) , 30 days 93 22 46 32 Survival Acc. No. 246021 Wilson, 1981 Core

Life-Cycle Toxicity Test

Fathead minnow (Pimephales promelas) 95.3 7.5 15 10.6 larval growth 43284601 Dionne, 1994 Core

1 defined as the geometric mean of the NOAEC and LOAEC.



### Freshwater Invertebrates, Acute

The following are the results of acute toxicity testing with freshwater invertebrates using technical grade diclofop-methyl and a formulated product. The mean LC 50 

### value of the two core
studies with the TGAI is 0.39 ppm. The LC 50 

### obtained from a test w ith a formulated product was similar (0.37 ppm AI). Because the LC50's fa ll within the range of 0.1 to 1 ppm, diclofopmethyl is classified as highly toxic to freshwat er fish on an acute basis. The test guideline requirement for the TGAI (72-2(a)) is fulfilled by 41573303 and USEPA (1979), and the test guideline requirement for a TEP (72-2(b)) is fulfilled by 4141606304.

Acute toxicity to freshwater invertebrate

Species Static or Flow-through % AI 48-hour LC 50 /

EC 50 (ppm) Toxicity Category MRID No.

Author/Year Study

Classification

Waterflea (Daphnia magna)

, static 95.1 0.23 Highly toxic 41573303

Frank et al. , 1989 Core

Waterflea (Daphnia magna) “Technical” 0.54 Highly toxic USEPA, 1979 Core

Waterflea 34.8 1.06 (formulation) Moderately toxic 41606304 Core

### Page 44 of 50 Acute toxicity to freshwater invertebrate
(Daphnia magna)

, static 0.37 (a.i.) (formulation), highly toxic (a.i.) Smith & Schweitzer, 1990

Waterflea (Daphnia magna) 34.8 1.9 (formulation) 0.66 (a.i.) Moderately toxic (formulation), highly toxic (a.i.) ESVIIH, 1978 Supplemental



### Freshwater Invertebrate, Chronic

The following are the results from a freshwater aqua tic invertebrate life-cycl e test using technical diclofop-methyl. This test f ound that diclofop-methyl caused a reduction in number of eggs produced at a concentration of 166 ppb, whereas a concentration of 64 ppb caused no significant observed effect. The test guideline requi rement (72-4) is fulfilled by MRID 41737902.

Life-cycle toxicity with a freshwater aquatic invertebrate

.

Species, Study
type % ai 21-day

NOAEC (ppb) LOAEC (ppb) MATC 1 (ppb) Endpoints

Affected MRID No.

Author/Year Study

Classification

Waterflea (Daphnia magna)

, static renewal 95.1 64 166 103 Number of young produced 41737902 Smith, 1990 Core

1 defined as the geometric mean of the NOAEC and LOAEC.



### Toxicity to Estuarine and Marine Animals

Estuarine and Marine Fish

Toxicity testing with estuarine/marine fish is re quired for current uses of diclofop-methyl (wheat, barley, and turf) because some of these uses can occur in coastal ar eas. Diclofop-methyl is highly acutely toxic to freshwater fish and invertebrates.

The majority of use is on wheat and barley, which is grown mostly in inland areas. Use on turf is only as a Special Local Need regi stration for use on golf courses in 11 states and is a minor use of diclofop-methyl (2.6% of pounds sold). Howe ver, a small portion of the golf course use is expected to be adjacent to estuarine areas. Labe ls restrict use to within 100 feet of any water body. Chronic toxicity testing with a marine/estuarine fi sh is not required.

Estuarine and Marine Invertebrates, Acute

Toxicity testing with estuarine/ marine invertebrates is require d for current uses of diclofopmethyl (wheat, barley, and turf) because some ofthese uses occur in coastal areas. Diclofopmethyl is highly acutely toxic to freshwater fish and invertebrates. Acute oyster toxicity studies have been conducted with diclofop-methyl and the diclofop-methyl metabolite 2-(4-(2,4- dichlorophenoxy) phenoxy) propion ic acid (Acc. No. 245123; howev er, the results of these
studies are considered invalid be cause the percent active ingredient of the test material was not identified. Chronic toxicity testing with a marine /estuarine invertebrate is not required at this
time. Labels restrict use to w ithin 100 feet of any water body.

### Page 45 of 50 

### Toxicity to Plants

Terrestrial

Tier 2 terrestrial plant testing is required for diclofop-methyl becau se it is an herbicide that has terrestrial non-residential outdoor use patterns, co uld move off the applica tion site via runoff and spray drift (for aerial applicati ons), and might affect endangered or threatened plant species associated with the application sites. The re quired testing consists of seedling emergence and vegetative vigor tests with ten crop species. Six of the species must be dicotyledonous and represent at least four families. One of these species must be soybean ( Glycine max ) and a second must be a root crop. The remaining four species must be monocotyledonous and represent at least two families. One of these species must be corn ( Zea mays ).

The following are the results of tier 2 seedling em ergence testing. Ryegrass is the most sensitive monocotyledon and the most sensitiv e species overall, with an EC 25 

### of 0.012 lb ai/A and an
NOAEC of 0.0063 lb ai/A

. 

### Lettuce was the most sensitive di cotyledon. These data indicate that monocotyledons are much more sensitive to di clofop-methyl than are dicotyledons. The guideline for seedling emergence testi ng (123-1a) is fulfilled (MRID 41606306).

Seedling emergence toxicity of nontarget terrestrial plant (Tier II)

Species % ai EC 25 (lb ai/A) NOAEC (lb ai/A) Most Sensitive Endpoint MRID No.

Author/Year Study

Classification

Corn (monocot) 95.1 0.083 0.100 Radical length 41606306 Chetram, 1990 Core

Oat (monocot) 95.1 0.362 0.125 Plant height 41606306 Chetram, 1990 Core

Onion (monocot) 95.1 0.394 0.500 Plant height 41606306 Chetram, 1990 Core

Ryegrass (monocot) 95.1 0.012 0.0063 Plant height (based on

the EC 25 ) or radical length (based on the NOAEC) 41606306 Chetram, 1990 Core

Carrot (dicot, root crop) 95.1 >1.0 1.0 N/A 41606306 Chetram, 1990 Core

Soybean (dicot) 95.1 > 1.0 1.0 N/A 41606306 Chetram, 1990 Core

Cabbage (dicot) 95.1 1.25 0.5 Plant height 41606306 Chetram, 1990 Core

Cucumber (dicot) 95.1 > 1.0 1.0 N/A 41606306 Chetram, 1990 Core

Lettuce (dicot) 95.1 0.792 0.25 Plant dry weight 41606306 Chetram, 1990 Core

Tomato (dicot) 95.1 > 1.0 1.0 N/A 41606306 Chetram, 1990 Core

### Page 46 of 50 

### The following are results of Tier 2 vegetative vigor testing. Results were similar to the seedling emergence test in showing that monocotyledons ar e much more sensitive to diclofop-methyl than are dicotyledons. Ryegrass is the most sensitive monocotyledon and the most sensitive species overall, with an EC 25 

### of 0.10 lb ai/A and an NOAEC of 0.0625 lb ai/A. Lettuce was the most sensitive dicotyledon. The guideline for vegeta tive vigor testing (123- 1b) is fulfilled (MRID 41606306).

Vegetative vigor toxicity to nontarget terrestrial plant (Tier II)

Species % ai EC 25 (lb ai/A) NOAEC (lb ai/A) Most Sensitive Endpoint MRID No.

Author/Year Study

Classification

Corn (monocot) 95.1 0.101 0.05 Plant height 41606305 Chetram, 1990 Core

Oat (monocot) 95.1 > 0.5 0.5 N/A 41606305 Chetram, 1990 Core

Onion (monocot) 95.1 > 1.0 1.0 N/A 41606305 Chetram, 1990 Core

Ryegrass (monocot) 95.1 0.10 0.0625 Plant height 41606305 Chetram, 1990 Core

Carrot (dicot, root crop) 95.1 > 1.0 1.0 N/A 41606305 Chetram, 1990 Core

Soybean (dicot) 95.1 >1.0 1.0 N/A 41606305 Chetram, 1990 Core

Cabbage (dicot) 95.1 4.69 0.500 Plant height 41606305 Chetram, 1990 Core

Cucumber (dicot) 95.1 >1.0 1.0 N/A 41606305 Chetram, 1990 Core

Lettuce (dicot) 95.1 1.00 0.50 Plant dry weight 41606305 Chetram, 1990 Core

Tomato (dicot) 95.1 >1.0 1.0 N/A 41606305 Chetram, 1990 Core



### Data are not available on the phytotoxicity of diclofop acid, the major de gradation product of diclofop-methyl.

Aquatic Plants

Aquatic plant testing is required for any herbicide that has outdoor non-residential terrestrial uses that may move off-site by runoff, by drift, or that is applied di rectly to water. Only one aquatic plant study (growth inhibition using duck weed) has been submitted for diclofop-methyl or diclofop acid. Results indicate no inhibition above 50% (LC50 for frond number was 1.295 Time-weighted average concentration with an NOAEC of 1.0 mg/L time-weighted average concentrations).

### Page 47 of 50 

# APPENDIX C: Example of SIP INPUT and OUTPUT

Drinking Water Exposure Drinking water for the purposes of terrestrial organism risk assessment is defined as that portion of an organism’s daily water intake that is no t met by dietary or metabol ic sources and must be consumed in liquid form. Typical drinking water sources for wildlife in pesticide use areas may include on-field puddles, irriga tion equipment (e.g., drip irrigati on in grape cultivation), dew deposited on treated plants, and o ff-field surface water exposures.

The Screening Imbibition Program (SIP v.1.0, Released June 15, 2010) was used to calculate an upper bound estimate of exposure us ing diclofop-metyl’s solubility in water (0.8 mg/L at 25 o 

### C). Using TGAI data for the most sensitive acute (LD 50 

### > 2250 mg a.i./kg-bw for the bobwhite quail, MRID 40072903) and chronic (NOAEC = 200 mg a.i./kg-diet, mallard duck, MRID 243472) avian toxicity endpoints and the most sensitive acute (LD 50 

### = 580 mg a.i./kg-bw, rat, MRID 097107) and chronic (reproduction NOAE C = 30 a.i./kg-diet, MRID 097111) mammalian toxicity endpoints. Drinking wa ter exposure alone was determined not to be a potential pathway of concern for avian and mammalian species on an acute and chronic basis. Detailed information about the SIP v.1.0, as well as the tool, can be found on the EPA’s website at http://www.epa.gov/pesticides/science/models_pg.htm#terrestrial

.

Table 1. Inputs
Parameter Value
Chemical name Diclofop-methyl Solubility (in water at 25 o C; mg/L) 0.8

Mammalian LD 50 (mg/kg-bw) 580 Mammalian test species laboratory rat Body weight (g) of "other" mammalian species

Mammalian NOAEL (mg/kg-bw) 30 Mammalian test species laboratory rat Body weight (g) of "other" mammalian species

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

Mallard NOAEC (mg/kg-diet) 200 Bobwhite quail NOAEC (mg/kg-diet) 200

### Page 48 of 50 Table 2. Mammalian Results
Parameter Acute Chronic Upper bound exposure (mg/kg-bw) 0.1376 0.1376 Adjusted toxicity value (mg/kg-bw) 446.1131 23.0748 Ratio of exposure to toxicity 0.0003 0.006

Conclusion* Drinking water exposure alone is NOT a potential concern for mammals Drinking
water
exposure alone is

NOT a potential

concern for mammals

Table 3. Avian Results
Parameter Acute Chronic Upper bound exposure (mg/kg-bw) 0.6480 0.648 Adjusted toxicity value (mg/kg-bw) 1588.5471 9.9225 Ratio of exposure to acute toxicity 0.0004 0.0653

Conclusion* Drinking water exposure alone is NOT a potential concern for birds Drinking
water
exposure alone is

NOT a potential

concern for birds

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

### Page 49 of 50 

# APPENDIX D: STIR inputs and outputs

Inhalation Exposure The Screening Tool for Inhalation Risk (STI R v.1.0, November 19, 2010) was used to calculate an upper bound estimate of exposure using di clofop-methyl’s vapor pressure (1.9 x 10 -7 

### mm Hg at 25 o 

### C) and molecular weight (341.19 g/mol) for vapor phase exposure as well as the maximum application rate (1 lbs a.i./A, which is the maxi mum seasonal application rate to wheat and method of application (aerial spray) for spray drift. STIR incorporates results from several toxicity studies including acute oral and inhalati on rat toxicity endpoints obtained from the “six-pack” of core studies, which are a series of six guideline studie s that are submitted to the Registration Division of the Office of Pesticide Progr ams on laboratory rats for technica l and formulated products of a pesticide (rat acute oral (TGAI): LD 50 

### = 557 mg a.i./kg-bw; rat inhalation (TGAI): LC 50 

### = >1.36 mg/L (data from Footprint Database). In additio n, the most sensitive acute oral avian toxicity endpoint (bobwhite quail, LD 50 

### = 2250 mg a.i./kg-bw was used. Based on the results of the STIR model, inhalation exposure alone was not determin ed to be a potential pathway of concern for avian or mammalian species on an acute basis as a result of spray applications of diclofop-methyl.

Inhalation exposure via spra y drift and/or vapor-phase of the pesticide alone does not appear to be of concern. The analysis of the inhalation route in STIR does not consider that aggregation with other exposure pathways such as dietary, dermal , or drinking water may contribute to a total exposure that has a potential for e ffects to non-target animals. Ho wever, the Agency does consider the relative importance of other r outes of exposure in situations wh ere data indicate that pesticide exposures through other rout es may be potentially signi ficant contributors to wildlife risk (USEPA, 2004). Detailed information about STIR v.1.0, as well as the tool, can be found on the EPA’s
website at: http://www.epa.gov/pesticides/science/models_pg.htm#terrestrial

.



# Input

Application and Chem ical Information

Enter Chemical Name Diclofop-methyl
Enter Chemical Use wheat Is the Application a Spray? (enter y or n) y If Spray What Type (enter ground or air) air
Enter Chemical Molecu lar Weight (g/mole) 341.19 Enter Chemical Vapor Pressure (mmHg) 1.90E-07 Enter Application Rate (lb a.i./acre) 1

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) 557

Enter Lowest Rat Inhalation LC 50 (mg/L) 1.36

### Page 50 of 50 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 ) 3.49E-03 Maximum 1-hour Vapor Inhalation Dose (mg/kg) 4.39E-04
Adjusted Inhalation LD 50 3.06E+01
Ratio of Vapor Dose to Adjusted Inhalation LD 50 1.43E-05 Exposure not Likely Significant Maximum Post-treatment Spray Inhalation Dose (mg/kg) 9.61E-02 Ratio of Droplet Inhalation Dose to Adjusted Inhalation LD 50 3.14E-03 Exposure not Likely Significant



### Results Mammalian (0.015 kg ) Maximum Vapor Concentration in Air at Saturation (mg/m 3 ) 3.49E-03 Maximum 1-hour Vapor Inhalation Dose (mg/kg) 5.51E-04
Adjusted Inhalation LD 50 8.10E+01
Ratio of Vapor Dose to Adjusted Inhalation LD 50 6.81E-06 Exposure not Likely Significant Maximum Post-treatment Spray Inhalation Dose (mg/kg) 1.21E-01 Ratio of Droplet Inhalation Dose to Adjusted Inhalation LD 50 1.49E-03 Exposure not Likely Significant