OFFICE OF CHEMICAL SAFETY AND POLLUTION PREVENTION UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
WASHINGTON

, D.C. 20460

PC Code: 122019
DP Barcode: 423550

MEMORANDUM March 3, 2015

SUBJECT: Preliminary Environmental Fate and Ecological Risk Assessment for the Registration Review of Propoxycarbazone-sodium

FROM: Elyssa Arnold, Biologist James Lin, Environmental Engineer Environmental Risk Branch 2 Environmental Fate and Effects Division (7507P)

REVIEWED Donna Judkins, Biologist
BY: Greg Orrick, Environmental Scientist Environmental Risk Branch 2 Environmental Fate and Effects Division (7507P)

THROUGH: Brian Anderson, Branch Chief Environmental Risk Branch 2 Environmental Fate and Effects Division (7507P)

TO: Lata Venkateshwara, Chemical Review Manager Avivah Jakob, Team Leader Neil Anderson, Acting Branch Chief Risk Management and Implementation Branch 3 Pesticide Re-evaluation Division (7508P)

Attached please find the Environmental Fate and Effects Division’s Preliminary Environmental Fate and Ecological Risk Assessment for the Registration Review of propoxycarbazone-sodium. The assessment characterizes potential ecological risk from the currently registered uses of propoxycarbazone-sodium on wheat, triticale, rangeland, pastures , and Conservation Reserve Program land. The assessment finds that terrestrial plants are the only taxa for which risks from these uses exceed levels of concern. Direct effects on terrestrial plants could result in indirect effects to all other taxa. Digitally signed by JAMES LIN DN: c=US, o=U.S. Government, ou=USEPA, ou=Staff, cn=JAMES LIN, dnQualifier=0000014809
Date: 2015.03.03 17:40:18 -05'00'

Anderson, Brian

2015.03.04
16:45:03 -05'00' 2015.03.04
16:48:06 -05'00'

2015.03.04 17:19:38 -05'00'

## Preliminary Environmental Fate and Ecological Risk Assessment for the Registration Review of Propoxycarbazone-sodium

Propoxycarbazone-sodium
CAS 181274-15-7 PC Code 112019

3 March 2015

Prepared by Elyssa Arnold, Biologist Jim Lin, Environmental Engineer U.S. Environmental Protection Agency Office of Pesticide Programs Environmental Fate and Effects Division (EFED) Environmental Risk Branch II 1200 Pennsylvania Ave., NW Mail Code 7507P Washington, DC 20460 Reviewed by Donna Judkins, Biologist Greg Orrick, Environmental Scientist Brian Anderson, Branch Chief-Page 3 of 66- 

## Table of Contents

1. Executive Summary ............................................................................................................. .............................. 4
2. Pr oblem Form ulation ................................................................................................. ...................................... 6
2.1. Nature of Regula tory Action ................................................................................................... ................ 6
2.2. Stressor Source and Distribution .............................................................................................. .............. 6
2.2.1. Nature of the Ch emical Stressor ............................................................................................... ....... 6
2.2.2. Overview of Pesticide Usage ................................................................................................... .......... 7 2.3. Receptors ........................................................................................................ .......................................... 7
2.3.1. Aquatic and Terres trial Effects ............................................................................................... ......... 7
2.3.2. Ecosystems Potentially at Risk ................................................................................................ ......... 8
2.4. Assessment Endpoints .......................................................................................................... .................... 8 2.5. Conceptual Model .................................................................................................. ................................... 9 2.5.1. Risk Hypotheses ................................................................................................... ............................... 9 2.5.2. Conceptual Diagram ................................................................................................ ......................... 10 2.6. Analysis Plan ..................................................................................................... ...................................... 11 2.6.1. Measures of Exposure ........................................................................................... ......................... 11
2.6.2. Measures of Effect ............................................................................................. ............................. 13 2.6.3. Integration of Exposure and Effects ............................................................................ ................. 13 3. Analysis ............................................................................................................ ................................................ 15
3.1 Use Characte rizati on .......................................................................................................... ......................... 15
3.2. Exposure Charac terization ..................................................................................................... ............... 16
3.2.1. Environmental Fate and Transport Characterization ................................................................. 16
3.2.2. Measures of Aqua tic Exposure .................................................................................................. ..... 23
3.2.3. Measures of Terres trial Exposure .............................................................................................. .... 25
3.3. Ecological Effects Characterization ........................................................................................... ........... 28
3.3.1. Aquatic Effects Characterization .............................................................................................. ..... 28
3.3.2. Terrestrial Effects Ch aracterization .......................................................................................... .... 31
3.3.3. Review of Incident Data ....................................................................................................... ........... 34
4. Risk Characterization ......................................................................................................... ............................. 34
4.1. Risk Esti mation ............................................................................................................... ........................ 34
4.1.1. Aquatic Or ganisms ............................................................................................................. ............. 35
4.1.2. Terrestrial Or ganisms ......................................................................................................... ............ 35
4.2. Risk Des cription .............................................................................................................. ........................ 37
4.2.1. Risks to Aquati c Organisms .................................................................................................... ....... 37
4.2.2. Terrestrial Or ganisms ......................................................................................................... ............ 38
5. Listed Species of Con cern ..................................................................................................... ........................... 42
5.1. Evaluating Risks to Listed Species ............................................................................................ ............ 42
5.2. Taxonomic Groups Potentially at Risk .......................................................................................... ....... 43
6. Endocrine Disruptor Screening Program ......................................................................................... ............. 43
7. Conclusi ons ................................................................................................................... .................................... 44
8. Data Gaps ..................................................................................................................... .................................... 45
9. References .................................................................................................................... ..................................... 51
9.1. Submitted Product Chemistry and En vironmental Fate Studies ....................................................... 53
9.2. Submitted Ecotoxic ity Studies ................................................................................................. .............. 56 Appendix A. SWCC Modeling Summar y for Propoxycarbaz one-sodium .......................................................... 59 Appendix B. Example T-REX Input and Ou tput for Propoxycarbazone-sodium .............................................. 61 Appendix C. Example TERRPLANT (v. 1.2.2) Inpu t and Output for Propoxycarbazone-sodium .................. 64 Appendix D. STIR Results fo r Propoxycarbaz one-sodium ......................................................................... ......... 65 Appendix E. SIP Results fo r Propoxycarbaz one-sodium .......................................................................... ............ 66-Page 4 of 66- 1. Executive Summary

The preliminary risk assessment (PRA) examines the potential ecological risks associated with labeled uses of the herbicide propoxycarbazone-sodi um based on the best available scientific and commercial information on the us e, environmental fate and transport, and effects of propoxycarbazone-sodium on non-targ et organisms. Propoxycarba zone-sodium is a sulfonylamino-carbonyl-triazolinone herb icide registered for use on wheat, triticale, rangeland, pastures

, and Conservation Reserve Program land. It is used for post-emergence control of grasses and broadleaf plants at a maximum single application rate of 0.0525 lb a.i./A.

Propoxycarbazone-sodium is very mobile in soil , with high water solubility (42,000 mg/L) and low soil partitioning coefficients (Kd = 0.22 to 1.07) . The chemical has a low vapor pressure (7.1
x 10 -11 mmHg) and is not likely to bioaccumulate (Kow = 0.028). Propoxycarbazone-sodium degrades slowly with fairly l ong half-lives by al l measured routes incl uding hydrolysis (433-495 days at pH 7), photolysis (37-94 days), aerobic soil metabolism (8.7-224 days), aerobic aquatic metabolism (107-210 days), and anaerobic aquatic metabolism (1155 days). Terrestrial field dissipation half-lives ranged from 12 to 56 days. While propoxycarbazone-sodium has a number of major degradates, none were identi fied to be of ecological concern.

Propoxycarbazone-sodium is practically non-toxic on an acute e xposure basis to all animal taxa, including birds, mammals, terrest rial invertebrates, fish, and aquatic invertebrates. Chronic toxicity effects were observed at high doses in studies of birds and mammals. Propoxycarbazonesodium is very highly toxic to the vascular aquatic plant duckweed. The next most sensitive aquatic plant species tested was green algae, wh ich was two orders of magnitude less sensitive than duckweed. Consistent with the herbicidal mode of action, terrestrial pl ants are sensitive to propoxycarbazone-sodium expos ure. Similar levels of toxicity were obs erved to monocots and dicots in both the seedling emergenc e and vegetative vigor studies.

Although data from the acute cont act and oral toxicity test s with young adult honey bees ( Apis mellifera ) indicate propoxycarbazone-sodi um is practically non-toxic to bees on an acute exposure basis, there is uncerta inty regarding the pot ential acute and chr onic effects of the compound on honey bee larval development and surviv al as well as potentia l for chronic effects of adult bees. Since propoxycarbazone-sodium is a systemic herbicide, residues may be transported by the plant into pol len and/or nectar and represen t a route of exposure for bees through ingestion. Studies to ad dress these uncertainties are specified by the Guidance for Assessing Pesticide Risks to Bees (USEPA et al. , 2014). See Section 8 for additional details. The data gaps include:
1. Non-guideline Study (Tier 1) – Honey bee larvae acute oral toxicity
2. Non-guideline Study (Tier 1) – Honey bee adult chronic oral toxicity
3. Non-guideline Study (Tier 1) – Honey bee larvae chronic oral toxicity
4. Non-guideline Study (Tier 2) – Semi-field te sting for pollinators (tunnel or colony feeding studies)
5. Non-guideline Study (Tier 2) – Field tria l of residues in pollen and nectar
6. OCSPP 850.3040 (Tier 2 or 3) – Fi eld testing for pollinators-Page 5 of 66- Terrestrial plants are the only taxa for which risks exceed levels of concern for currently registered propoxycarbazone-sodium uses. Direct effects on terrestri al plants could result in indirect effects to all other taxa due to habitat modifications ( e.g. , food sources, shel ter, and areas to reproduce). Spray drift buffers from treated fields would need to be >1,000 ft for listed terrestrial plants and up to 900 ft for non-listed terrestrial plants to d ecrease risks below the levels of concern. Additionally, there is a potential for damage to terrestrial plants if surface or groundwater contaminated with propoxycarb azone-sodium is used for irrigation.

Figure 1.1 and Table 1.1 give a broad overview of the pote ntial risk concer ns and supporting evidence for registered uses of propoxycarbazone-sodium.

Figure 1.1. Graphic Summary of Potential Risks of Current Uses of Propoxycarbazone-sodium

Table 1.1. Evidence of Risk to Taxonomic Groups from Current Us es of Propoxycarbazone-sodium Predominant Evidence of Negligible Risk Predominant Evidence of Risk
Mammals, birds, fish, aquatic invertebrates, aquatic plants: All RQs <LOC for listed and non-listed species. No incidents reported. Terrestrial Plants: RQs > LOC (up to 850) for listed and non-listed monocots and dicots for all uses. Multiple incidents reported.
Limited Evidence of Negligible Risk Limited Evidence of Risk
Terrestrial Invertebrates: No mortality observed in acute

contact and acute oral studies on adult honey bees. No chronic toxicity data or larval toxicity data available. N/ACertainty



# Risk Propoxycarbazone-sodium

Terr. Plants Fish Mammals Birds

Aq. Inverts Aq. Plants

Terr. Inverts-Page 6 of 66- 2. Problem Formulation

The purpose of problem formulation is to provide the foundation for the environmental fate and ecological risk assessment being conducted for the representative labeled uses of propoxycarbazone-sodium. The probl em formulation sets the objec tives for the risk assessment and provides a plan for analyzing the data and characterizing th e risk (USEPA, 1998). Distinct from other Registration Review cases, no preli minary problem formulation was developed for propoxycarbazone-sodium due to a re latively complete set of fa te and transport as well as ecotoxicity data at the time of the initial docket opening.

Ecological risk from propoxycarbazo ne-sodium use on wheat was previo usly assessed at the time of the initial pesticide registration in 2004 (USEPA, 2004b). Propoxycarbazone-sodium use on pasture and rangeland was subsequently assesse d in 2008 (USEPA, 2008). Updated assessment methods and models are used in this document. Conclusions regard ing risks to non -target species are consistent with those in previous assessme nts with the exception of listed vascular aquatic plants. As a result of sl ight differences in the ca lculated toxicity endpoint 1 , risks exceeding levels of concern were identified in the 2008 assessment, but are not identified in this assessment. Risks exceeding the levels of concern fo r terrestrial plants are identifie d in all previous and current

assessments.

2.1. Nature of Regulatory Action

The risk assessment is conducted as part of the Agency ’s Registration Review process for pesticide active ingredients. The Registration Review process was established under the Food Quality Protection Act (FQPA 1996), which ame nded the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA).

2.2. Stressor Source and Distribution

2.2.1. Nature of the Chemical Stressor

Propoxycarbazone-sodium is a su lfonyl-amino-carbonyl-triazolinon e herbicide used for the selective post-emergence control of grasses and broadleaf plants. Propoxy carbazone is absorbed through the foliage and root syst ems of plants, and acts as an inhibitor of the enzyme acetolactase synthase (ALS). The chemical prof ile of propoxycarbazone-sodium is provided in
Table 2.1 . Chemical names and structures of propoxy carbazone-sodium degrad ates are listed in
Table 3.3 . This screening-level ecol ogical risk assessment focuse s on propoxycarbazone-sodium parent only because none of the identified transformation products were found to be of ecological concern.

1 The 2008 assessment calculated RQs for listed vascular aquatic plant species using the EC 05 of 0.002 μg a.i./L. Because there is a definitive NOAEC value of 0.0031 μg a.i./L from the same study (MRID 45012815), this assessment uses the NOAEC rather than the EC 05 . The exposure estimate is 0.0023 μg/L in both assessments.-Page 7 of 66- Table 2.1. Chemical Profile of Propoxycarbazone-sodium

Common name Propoxycarbazone-sodium
IUPAC name sodium {[2-(methoxycarbonyl)phenyl]sulfonyl}[(4,5-dihydro-4- methyl-5-oxo-3-propoxy-1H-1,2,4-triazol-1-yl)carbonyl]azanide
CAS name Methyl 2-((((4,5-dihydro-4-methyl-5-oxo-3-propoxy-1H-1,2,4-triazol1-yl)carbonyl)amino)sulfonyl)benzoate sodium salt
Structure

Pesticide type Herbicide
CAS number 181274-15-7 Empirical formula C 15 H 17 N 4 NaO 7 S
Molecular mass 420.37 g/mol

2.2.2. Overview of Pesticide Usage

Propoxycarbazone-sodium, an herb icide that controls certain post-emergent grasses and broadleaf weeds, was initially registered in June 2004. There are curren tly six active Section 3 registrations for propoxycarbazone-sodium , including one techni cal, OlympusTM MKH 6561 Technical (EPA Reg No. 264-808). The five end-use p roducts include Olympus ® 70% Water Dispersible Granular Herbicid e (EPA Reg No. 264-809), Olympus TM Flex Herbicide (EPA Reg No. 264-833), Olympus TM Rangeland Herbicide (EPA Reg No. 264-1074), Rimfire TM Herbicide (EPA Reg No. 264-847) , and Rimfire TM Max Herbicide (EPA Reg No. 264-1099). Propoxycarbazone-sodium is currently registered for use on wheat, triticale, rangeland, pastures

, and Conservation Reserve Program land. Based on available proprietary usage data, the predominant use of propoxycarbazone-sodiu m is on winter wheat (USEPA, 2014a). Propoxycarbazone-sodium products are water dispersible granules and are applied as a pre-plant, pre-emergence, and post-emergence application via ground (broadcast or hand-held spot treatment) or aerial methods. Application rates are similar for all use pa tterns. The highest annual and single maximum app lication rates are 0.0525 lb a.i./A. Specific use ra tes are discussed in
Section 3.1

.

Three of the propoxycarbazone-sodium products currently registered for use on wheat and triticale (Olympus TM Flex, Rimfire TM , and Rimfire TM Max) contain mesosu lfuron-methyl as a second active ingredient. This eval uation is limited to exposure to propoxycarbazone-sodium

, and does not include estimated concentrations of other activ e ingredient residues.

2.3. Receptors

2.3.1. Aquatic and Terrestrial Effects

The receptor is the biological ent ity that is exposed to the st ressor (USEPA, 1998). Consistent with the process described in the Overview Document (USEPA, 2004a), this risk assessment uses a surrogate species approach in its evaluation of propoxycarbazone-sodium . Toxicity data-Page 8 of 66- generated from surrogate test species, which are intended to be representative of broad taxonomic groups, are used to extrapolate potentia l effects on a variety of species (receptors) included under these ta xonomic groupings.

Acute and chronic toxicity data from studies s ubmitted by pesticide regi strants along with the available open literature are used to evaluate potential direct effects of propoxycarbazonesodium to aquatic and terrestrial r eceptors. The open literature st udies are located through EPA’s database ECOTOX ( http://cfpub. epa.gov/ecotox/ ), which provides a so urce for locating single chemical toxicity data for aquatic life , terrestrial plants, and wildlife.

2.3.2. Ecosystems Potentially at Risk

The ecosystems at risk are often extensive in scope ; therefore, it may not be possible to identify specific ecosystems at the screening level. In gene ral terms, terrestrial ecosystems potentially at risk could include the treated si te and areas immediately adjacent to the treated site that may receive drift, runoff, erosion, or discharged gr oundwater. These areas coul d include the treatment site itself, other cultivated fields, fencer ows and hedgerows, meadows, fallow fields or grasslands, woodlands, riparian habita ts, and other uncultivated areas.

Aquatic ecosystems potentially at risk include water bodies adjacent to or downstream from treated areas, and can include lentic systems, i.e. , ponds, lakes and impoundments (reservoirs), and lotic systems (streams and rivers). Aquatic ecosystems s upplied by groundwater, including cave ecosystems and areas supplied by seeps and springs, may be at risk from compounds that leach into the subsurface. For uses in coastal areas, aquatic habitat at potential risk includes marine and estuarine ecosystems. In evaluatin g aquatic exposure within water bodies, EFED considers the water column, sediment, and pore water as compartments of concern.

Propoxycarbazone-sodium is not identified as a cause of impairment for a ny water bodies listed as impaired under section 303(d) of the Clean Water Act. No Total Maximum Daily Loads (TMDLs) or water quality criteria have been developed for propoxycarbazone-sodium 2 . Office of Pesticide Programs (OPP) Aquatic Life Benchmarks 3 have not been established for propoxycarbazone-sodium.

2.4. Assessment Endpoints

Assessment endpoints represent the ac tual environmental value that is to be protected, defined by an ecological entity (species, community, or othe r entity) and its attrib ute or characteristics (USEPA, 1998). For propoxycarbazone-sodium , the ecological entities in clude the following: birds, amphibians, reptiles, mamm als, freshwater fish and invert ebrates, estuarine/marine fish and invertebrates, terrestr ial plants, insects, and aquatic plants and algae. The attributes assessed for each of these entities may includ e growth, survival, and reproduction.

The assessment endpoints are intended to re flect population sustaina bility and community

2 http://iaspub.epa.gov/tmdl_waters10/attains_na tion_cy.cause_detail_303d?p_cause_group_id=885

3 Office of Pesticide Programs’ Aquatic Life Benchmarks. http://www.epa.gov/oppefed1/ecorisk_ders/aquatic_life_benchmark.htm-Page 9 of 66- structure within ecosystems and hence relate back to ecosystems at risk. If risks are expected for given species/taxa based on the screening-level assessment, then risks might be expected to translate to higher levels of biological organization.

2.5. Conceptual Model

For a pesticide to pose an ecological risk, it must reach ecological r eceptors in biologically significant concentrations. An exposure pathway is the means by which a pe sticide move s in the environment from a source to an ecological receptor. For an ecol ogical pathway to be complete, it must have a source, a releas e mechanism, an environmental transport medium, a point of exposure for ecological receptors, and a feasible route of exposure. The conceptual model is intended to provide a written description and visu al representation of the predicted relationships between propoxycarbazone-sodium , potential routes of exposure , and the predicted effects for the assessment endpoint. The conceptual model consists of two major components: the risk hypotheses and a conceptual diagram (USEPA, 1998).

The conceptual model used to de pict the potential ecological risk associated with the proposed and existing uses of propoxycarbazone-sodium relies on previous assessments and the Agency’s current understanding of the environmental fa te and ecological effects of the chemical. Consistent with the intended use of propoxycarbazone-sodium as an herbicide, potential risk to non-target terrestrial plan ts is expected. Effects on plants, which represent the primary producers in an ecosystem, may result in secondary effects on consum ers. The model assumes that propoxycarbazone-sodium is capable of affecting terrestrial vertebrates and aquatic vertebrates and invertebrates, provided that e nvironmental concentrations are su fficiently elevated as a result of existing uses ( Figure 2.1 ).

Based on the previous ecological risk assessm ents (USEPA, 2004b, 2008), risks at the highest label rate of propoxycarbazone-sodium are expected for non-listed a nd listed terrestrial and semiaquatic plant species and listed aquatic vascular plant species. Due to th e potential risk from direct effects to these taxa, listed species in all taxa may potentially be affected indirectly due to alterations in their habitat ( e.g. , food sources, shelter, and areas to reproduce) if exposure to propoxycarbazone-sodium occurs.

2.5.1. Risk Hypotheses

For propoxycarbazone-sodium , the following ecological risk hypothesis is employed for the ecological risk assessment:

Given the existing uses of propoxycarbazone-sodium and its environmental fate properties, there is possible acute and ch ronic exposure to non -target aquatic and terrestrial organisms. When used in accordance with the label, propoxycarbazonesodium may result in adverse ef fects upon the survival, grow th, and reproduction of nontarget aquatic and terrestrial plants and animals. Bees and ot her pollinators may be at risk due to the systemic nature of the com pound and the possibility that residues could be transported to pollen and nectar on which bees forage. To the extent to which terrestrial and/or aquatic plants are affected by the registered uses of the herbicide, other taxa may-Page 10 of 66- be indirectly affected via direct effe cts on primary productivity and loss of habitat.

2.5.2. Conceptual Diagram

The potential exposure pathways and effect s of the proposed and existing uses of propoxycarbazone-sodium are depicted in Figure 2.1 . Solid arrows depict th e most likely routes of exposure and effects; dashed lin es depict potential r outes of exposure that are not considered likely for propoxycarbazone-sodium

.

Application methods for proposed and existing uses of propoxycarbazone-sodium involve ground (broadcast or hand-held spot treatment) and aerial applications. Ecol ogical receptors that may be exposed to propoxycarbazone-sodium following such applications include terrestrial and semi-aquatic wildlife ( i.e. , mammals, birds, terrestrial-phase am phibians, terrestrial invertebrates, and reptiles) and plants. In addition, aquatic receptors ( e.g ., freshwater and estuarine/marine fish and invertebrates, aquatic-phase amphibians, and plants) may be exposed as a result of movement of propoxycarbazone-sodium via spray drift and runoff fr om the site of application. The conceptual framework for assessment of potential ecological risk associated with propoxycarbazone-sodium is depicted in Figure 2.1 ; potential endpoints, stressors, and ecological effects are identifi ed based on this model.

For terrestrial organisms, the primary route of exposure assessed at the screening level is the dietary route, via consumption of food items such as plant l eaves or insects that have propoxycarbazone-sodium residues as a result of spraying. The assessment considers exposure of non-target terrestrial inverteb rates through oral ingestion of residues and through contact, e.g. , as a result of direct deposition or spray drift. Direct contact and r oot uptake are the major routes of exposure considered for terr estrial and wetland plants.

Based on propoxycarbazone-sodium ’s vapor pressure (7.1x 10 -11 torr), it is not expected to readily volatilize, so this risk assessment doe s not take into account potential atmospheric transport in estimating environmental concentra tions. The Screening Tool for Inhalation Risk (STIR) (see Section 2.6.1.2 ), which compares inhalation expos ure estimates to available avian and mammalian toxicity data, also indicates that inhalation of vapor and spray drift are not of concern, so this assessment do es not evaluate potential atmospheric transport in estimating environmental concentrations. Additionally, the Screening Imbibition Pr ogram (SIP) indicates that drinking water exposure may be a potential pathway of concern for w ildlife due to the high solubility (42,000 mg/L); however, risks are unlik ely due to the non-definitive toxicity endpoints for both birds and mammals and low application rates. The current assessment will consider potential chronic risk to w ildlife through drinking water e xposure qualitatively only. This assessment does not account for possible ingestion of propoxycarbazone-sodium residues by terrestrial animals via contaminated grit or pr eening activities, and doe s not evaluate potential uptake through dermal absorption.

For aquatic assessments, the major routes of ex posure for aquatic animal species are considered to be through the respiratory su rface (gills) or the integument. Organisms in habitats supplied primarily by groundwater discharge ( e.g. , seeps, springs) may rece ive a different level of exposure than organisms in surface rivers, streams, lakes, and impoundments. Similar to-Page 11 of 66- terrestrial organisms, exposur e of aquatic organisms to propoxycarbazone-sodium may also occur through ingestion of residu es in sediment and forage. P ropoxycarbazone-sodium is hydrophilic, with a log octanol-water partit ion coefficient (logK ow ) of -1.55. Therefore, propoxycarbazone-sodium residues are not expected to bioconcentrate in fish.

Figure 2.1. Conceptual Model Depicting Potential Risks to Non-target Species from the Use of Propoxycarbazone-sodium. Solid arrows depict the most likely routes of exposure and effects; dashed lines depict potential routes of exposure th at are not considered likely.

2.6. Analysis Plan

2.6.1. Measures of Exposure

2.6.1.1. Measures of Aquatic Exposure

Measures of exposure to aquatic animals and pl ants are concentrations in surface water and benthic sediment pore water simulated by the Surfa ce Water Concentration Calculator (SWCC, v 1.106, May, 2014), used to generate estimated e nvironmental concentrations (EECs) of propoxycarbazone-sodium that may occur from the chemical’s registered uses. The EECs used in assessment of acute risk are 1-in-10 year return frequency daily maximum values (referred to as “peak” values). For chronic risk assessment, m ean concentrations over a specified duration are generated. In both cases, each modele d site is selected to represen t a site expected to be more vulnerable to runoff than most locations where use may occur ( e.g. , based on the crop being grown). The SWCC simulates pesticide runoff fr om a treated area to an adjacent water body following applications, in addition to loadings that occur directly to the water as a consequence of spray drift. Stresso r

Source/ Transport Pathways Direct Deposition Runoff Erosion Leaching (Infiltration/ Percolation

Source/ Exposure Media Terrestrial Plants Terrestrial Invertebrates Terrestrial Plants Soil Receiving Water Body/ Sediment Groundwater

Tested Exposure Route Ingestion Direct Contact Root Uptake Gill or Integument U p take

Receptors

Attribute Changes Terrestrial Vertebrates & Invertebrates Terrestrial Plants

Individual Animals: Reduced survival and/or reproduction Aquatic Invertebrates Aquatic Vertebrates

Individual Plants: Seedling emergence Ve g etative vi g or Individual Animals: Reduced survival and/or re p roduction Plant Population: Reduced population
g rowth

Aquatic Plants Uptake/ Adsorption Spray Drift Volatilization Atmospheric Transport Propoxycarbazone-sodium

Direct Contact

Terrestrial Invertebrates-Page 12 of 66- 2.6.1.2. Measures of Terrestrial Exposure

Terrestrial wildlife could be exposed to propoxycarbazone-sodium via consumption of residues on food items from spray applications. For spray applications, the T-REX model (T errestrial
R esidue EX posure model; v. 1.5.1; June 6, 2013b) is us ed to predict dietary exposure to propoxycarbazone-sodium residues on foliar surfaces and inse cts using the Kenaga nomogram as modified by Fletcher (Hoerg er and Kenaga 1972, Fletcher et al. 1994). In this assessment, the default foliar dissipation half-l ife of 35 days was used for te rrestrial modeling purposes.

The TERRPLANT (v. 1.2.2; December 26, 2006) mode l is used to derive EECs relevant to terrestrial and wetland plants for the uses of propoxycarbazone-sodium . The model assumes that default fractions of the intended application will be transported to an adjacent field through runoff and spray drift. Measures of exposure to terrestrial plants are expressed as a fraction of the mass of the propoxycarbazone-sodium applied to a treated field.

To characterize potential non-targ et plant exposure from spray drift alone, Tier 1 modules in AgDRIFT (v. 2.1.1, December 2011) were used to estimate how far off-site spray drift exposure might occur at a level known to cause adverse effect s in terrestrial plant toxi city studies. Four of the five end-use product labels for propoxycarbazone-sodium specify that the products should be applied using nozzles and pressures that generate a Medium spray droplet size category. The Olympus ® label differs from the others; it specifie s that the product should be applied using nozzles and pressures that generate a Coarse spray droplet size cate gory. The droplet size categories specified on the labels will be used for modeling in AgDRIFT.

The Screening Tool for Inhalation Risk (STI R v.1.0, November 19, 2010) was used to calculate an upper-bound estimate of wildli fe inhalation exposure using propoxycarbazone-sodium ’s vapor pressure and molecular weight for va por phase exposure as well as the maximum application rate and method of application for spra y drift. STIR incorporates results from several toxicity studies including acute oral and inhala tion rat toxicity endpoints obtained from the “sixpack” of core studies, which is a series of six guideline studies that are submitted to the Registration Division of the Office of Pesticid e Programs for technical and formulated products of a pesticide (LD 50 >5,000 mg/kg-bw/day, MRID 45012509; and inhalation LC 50 >5.03 mg/L, MRID 45012505) as well as the most sensitive acute oral avian toxicity endpoint (bobwhite quail
LD 50 >2,000 mg/kg-bw, MRID 45012813). Based on the results of the STIR model ( Appendix
D ), exposure through inhalation of sp ray drift or the vapor phase of propoxycarbazone-sodium is not determined to be a potential pathway of c oncern for either avian or mammalian species on an acute exposure basis.

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 effects to non-target animals. However, the Agency does consider the relative importance of other rout es of exposure in situations wh ere data indicate that pesticide exposures through other routes may be potentially significant contributors to wildlife risk (USEPA, 2004a). The risk characterization section ( Section 4.2 ), discusses the impact of consideration of other routes of exposure that have been identified as potentially important and the degree of certainty associated with screeni ng-level risk assessment conclusions. Detailed-Page 13 of 66- information about STIR v.1.0, as well as the tool, can be found on EPA’s website ( http://www.epa.gov/pesticides/sci ence/models_pg.htm#terrestrial ).

The Screening Imbibition Program (SIP v.1.0, rel eased June 15, 2010) was used to calculate an upper-bound estimate of wildlife drinking water exposure using propoxycarbazone-sodium’s solubility ( i.e ., 42,000 mg/L at 20 o C), and compared to the most sensitive acute and chronic avian and mammalian toxi city endpoints (see Table 3.13 ). Drinking water exposure alone was determined to be a potential pa thway of concern for birds and mammals on both an acute and chronic exposure basis. For a sample of the output generated by SIP v.1.0, please see Appendix
E

.

2.6.2. Measures of Effect

Measures of effect are obtained from a suite of registrant-submitted guideline studies which were conducted with a limited number of surrogate test species. The test species are not intended to be representative of the most sens itive species but rather were selected based on their ability to thrive under laboratory conditions. Toxicity testing repor ted in this risk assessment utilizes surrogate species to represent a ll freshwater fish (2000+) and bird (680+) spec ies in the U.S. In addition, the ECOTOX database (USEPA, 2009a) was searched in November 2014 to identify more ecological effects data for propoxycarbazone-sodium . No additional data were available that indicated greater sensitivity than those embodied in the regi strant-submitted study endpoints.

The acute measures of effect used in this screening-level assessment are the LD 50 (Lethal Dose),
LC 50 (Lethal Concentration), EC 50 (Effects Concentration), and IC 50 (Inhibition Concentration). These are measures of acute toxicity which resu lt in 50% of the respective effect in tested organisms. The endpoints for chronic measur es of exposure are the NOAEC (No Observed Adverse Effects Concentration) and the NOAEL (No Observed Adve rse Effects Level). Toxicity studies were submitted for freshwater fish a nd invertebrates, estuar ine/marine fish and invertebrates, aquatic and terrestrial plants, birds, mammals, and honey bees. The endpoints used for risk characterization were derived from studies which underwen t review and were classified as “acceptable” (conducted under guideline conditions and considered to be scientifically valid) or “supplemental” (cond itions deviated from guide lines but the results are considered to be scientifically valid).

2.6.3. Integration of Exposure and Effects

The exposure and toxicity effects data are integrat ed in order to evaluate the risks of adverse ecological effects on non- target species. For the risk assessment of propoxycarbazone-sodium

, the risk quotient (RQ) method is used to compare estimated exposure and measured toxicity values. The RQ method involves dividing estimated environmen tal concentrations (EEC) by acute and chronic toxicity values. The resulting RQs are then compared to the Agency’s Levels of Concern (LOC) (USEPA, 2004a) ( Table 2.2 ). The LOCs are used to indicate when applications of propoxycarbazone-sodium , as directed on the label, have the potential to cause adverse effects to non -target organisms.-Page 14 of 66- Table 2.2. Agency Risk Quotie nt (RQ) Metrics and Levels of Concern (LOC) Per Risk Class

Risk Class Risk Description RQ LOC
Aquatic Animals (fish and invertebrates)

Acute Potential for effects to non-listed animals from acute

exposures Peak EEC/LC 50 1 0.5

Acute Restricted Use Potential for effects to animals from acute exposures Risks may be mitigated through restricted use classification Peak EEC/LC 50 1 0.1

Acute Listed Species Listed species may be potentially affected by acute

exposures Peak EEC/LC 50 1 0.05

Chronic Potential for effects to non-listed and listed animals from chronic exposures 60-day EEC/NOAEC (fish) 1 21-day EEC/NOAEC (invertebrates)
Aquatic Plants Non-Listed Potential for effects to non-listed plants from exposures Peak EEC/LC 50 1 1 Listed Potential for effects to listed pl ants from exposures Peak EEC/NOAEC 1
Terrestrial Animals (mammals and birds) 2

Acute Potential for effects to non-listed animals from acute

exposures EEC/LC 50 (Dietary) 0.5 EEC/LD 50 (Dose)

Acute Restricted Use Potential for effects to animals from acute exposures Risks may be mitigated through restricted use classification EEC/LC 50 (Dietary) 0.2 EEC/LD 50 (Dose)

Acute Listed Species Listed species may be potentially affected by acute

exposures EEC/LC 50 (Dietary) 0.1 EEC/LD 50 (Dose)

Chronic Potential for effects to non-listed and listed animals from chronic exposures EEC/NOAEC 1

Terrestrial Invertebrates 3

Acute Potential for effects to bees and other insect pollinators from acute exposures to adults or larvae EEC/LD 50 0.4

Chronic Potential for effects to bees and other insect pollinators from chronic exposures to adults or larvae EEC/NOAEC 1.0

Terrestrial and Semi-Aquatic Plants

Non-Listed Potential for effects to non-target, non-listed plants from

exposures EEC/ IC 25 1

Listed Plant Potential for effects to non-target, listed plants from

exposures EEC/ NOAEC 1 EEC/ IC 05

1 LC 50 or EC 50
. 2 EEC based on upper bound Kenaga nomogram values for foliar exposure.

3 USEPA et al. , 2014. Guidance for Assessin g Pesticide Risks to Bees.

The Agency uses the probit dose-response relationship as a tool for providing additional information on the potential for acut e direct effects to individuals from listed species and aquatic animals that may indirectly a ffect the listed species of con cern (USEPA, 2004a). Individual effect probabilitie s are calculated based on a Microsoft ® Excel spreadsheet tool IECV1.1 (Individual Effect Chance Model Version 1.1) deve loped by the U.S. EPA, OPP, Environmental Fate and Effects Division (Jun e 22, 2004). These calculations are not presented in this-Page 15 of 66- assessment due to the lack of definitive acute toxici ty endpoints across all taxonomic groups for aquatic and terrestrial animals.

3. Analysis

3.1 Use Characterization

Propoxycarbazone-sodium is a su lfonyl-amino-carbonyl-triazolinon e herbicide used for the selective post-emergence control of grasses and broadleaf plants in wheat, triticale, rangeland, pastures, and Conservation Reserv e Program land. It can be appl ied either by aer ial or ground (broadcast or hand-held spot treatment) methods as a pre-plant, pre-emergence, or postemergence application . The only commercial available formulat ion is water dispersible granules (dry flowable). There are currently six active Section 3 registra tions for propoxycarbazonesodium, including one technical, OlympusTM M KH 6561 Technical (EPA Reg No. 264-808). The five end-use p roducts include Olympus ® 70% Water Dispersible Gran ular Herbicide (EPA Reg No. 264-809), Olympus TM Flex Herbicide (EPA Reg No. 264-833), Olympus TM Rangeland Herbicide (EPA Reg No. 264-1074), Rimfire TM Herbicide (EPA Reg No. 264-847) , and Rimfire TM Max Herbicide (EPA Reg No. 264-1099). Three of the currently registered propoxycarbazone-sodium products for use on wheat and triticale (Olympus TM Flex, Rimfire TM

, and Rimfire TM Max) contain mesosulfuron-methyl as a second active ingredient. Mesosulfuronmethyl use will not be assessed in this document.

Based on available proprietary usage data, the predominant use of propoxycarbazone-sodium is on winter wheat (USEPA, 2014a). According to the Screening Level Usage Analysis (SLUA) provided by the Biological and Economic Anal ysis Division (BEAD), between 2004 and 2012 an average of 30,000 lbs a.i./yr was used on winter wheat and 3,000 lbs a.i./yr was used on spring wheat in the United States (USEPA, 2014b). The SLUA reports that a maximum of 5% of winter and spring wheat crop acr es were treated with propoxycarbazone-sodium . These data do not include non-crop uses. Applicati on rates are similar fo r all use patterns. The highest annual and single maximum application rates are 0.0525 lb a.i./A.

Error! Reference source not found. Table 3.1 lists the maximum use patterns for the labeled use sites. The table is based on the “EFED Table 1 Re port,” which is a part of the Label Use Report Package created by BEAD in support of Registration Review (USEPA, 2014b).-Page 16 of 66- Table 3.1. Propoxycarbazone-sodium Maximum Application Rates

Use Single Max Application
Rate (lbs a.i./A) Max Application

Rate per Crop Cycle (lbs a.i./A) Max Application

Rate per

Year (lbs a.i./A) Min Application
Retreatment

Interval

(days) Max # of Applications

Per Year Application
Methods

Agricultural Fallow

/ Conservation
Reserve 0.0525 0.0525 0.0525 NA 1 Aerial, ground, spot

treatment

Pastures 0.0525 0.0525 0.0525 NA 1 Aerial, ground, spot

treatment (hand-held)

Rangeland 0.0525 0.0525 0.0525 NA 1 Aerial, ground, spot

treatment (hand-held)

Triticale 0.0395 NS 0.0395 NA 1 Aerial, ground

Wheat 0.0395 0.0525 0.0525 Fall followed by spring applications 2 1 Aerial, ground

NS=not specified; NA=not applicable

1 Applications may be split evenly at 0.0263 lbs a.i./A in the fall followed by an application at the same rate in the spring. The maximum rate in the fall is 0.0395 lbs a.i./A , which can be followed by an application of 0.0130 lbs a.i./A in the spring.

3.2. Exposure Characterization

3.2.1. Environmental Fate and Transport Characterization

The chemical and environmental fate characteristics of propoxy carbazone-sodium are listed in
Table 3.2 and are discussed in greater de tail in the following sections.

Table 3.2. Chemical Properties and Environmental Fate Parameters of Propoxycarbazone-sodium

Parameter Value Source
Selected Physical/Chemical Parameters
Molecular mass (molecular formula) 420 g/mol (C 15 H 17 N 4 O 7 SNa ) (Calculated)
Vapor pressure (20 °C) 7.1x 10 -11 torr Product Chemistry

Aqueous solubility (20 ° C, pH 7) 42,000 mg/L

Henry’s Law Constant (20°C) 9.35x10 -16 atm-m 3 /mol (Calculated)
Log octanol-to-water partition coefficient (log Kow) (20 ° C, pH 7) -1.55 Product Chemistry

Dissociation constant (pKa) 2.1

Persistence in Water
Hydrolysis half-life (20 ° C) pH 4: 110 days, pH 7: 495 days, pH 9: 408 days MRID 45012733
MRID 45012740
pH 4: 154 days, pH 7: 433 days, pH 9: 385 days MRID 45012724
MRID 45012725-Page 17 of 66- Parameter Value Source
Aqueous photolysis half-life (20 ° C) (pH 7) 93.5 days 37 days MRID 45012703
MRID 45012702

Persistence in Soil
Photodegradation half-life on soil 70 days 38 days MRID 45012729
MRID 45012728
Aerobic soil metabolism half-life (20°C) 77 days MRID 45012720
MRID 45012736
103 days MRID 45012723
21 days, 16 days, 83 days MRID 45012721
MRID 45012735
8.7 days, 46.5 days, 223.6 days MRID 45012722
MRID 45012736
Aerobic aquatic metabolism half-life (20 o C) 110 days, 107 days, 193 days, 210 days MRID 4512704
Anaerobic aquatic metabolism half-life (20 °C) 1155 days MRID 45012708
MRID 45012707
Mobility
Freundlich Adsorption coefficient (K d )

(Koc) (20 o C) 0.2504, 0.4968, 0.2239, 0.2134, 1.0747 L/kg 10.1, 18.7, 26 , 57.7, 66.7 MRID 45012634

Terrestrial Field Dissipation
Field Dissipation half-life US Soils 22.4 days US Soil 6.8 days US Soil 44.4 days European Soil 12, 15, 16, 22, 29, 34,

and 56 days MRID 45012716
MRID 45012719
MRID 45012715
MRID 45012738

Fish Bioconcentration
Not required – Kow (0.028) is less than 1,000

3.2.1.1. Transport and Mobility

Propoxycarbazone has high water solubility (42,000 mg/L in pH 7 water) and a low vapor pressure (7.1 x 10 -11 mmHg at 20 o C). The calculated Henry's Law Constant of 9.35 x 10 -16 atmm3/mol) indicates that propoxycarbazone is not expected to be volatile under field conditions and from water. The high water solubility and low soil partitioning coefficients (Kd = 0.22 to 1.07) indicate that it is very mo bile in soil. Due to its low Ko w value of 0.028, bioaccumulation is not likely to occur.

3.2.1.2. Degradation

Propoxycarbazone hydrolyzes at relatively slow ra tes, the half-lives at pH 7 are 495 and 433 days, with an average of 464 da ys. In pH 7 buffered water, the photolysis half-lives of propoxycarbazone are 93.5 and 37 days, with an average of 65.25 days. For photodegradation on soil, the half-lives are 70 and 38 days, with an average of 54 days. Several aerobic soil metabolism studies show a range of half-life values: 8.7 da ys, 16 days, 21 days, 46.5 days, 77-Page 18 of 66- days, 83 days, 103 days, and 224 days. For aerobi c aquatic metabo lism study, the ha lf-lives are 107 days, 110 days, 193 days, and 210 days. Anaer obic aquatic metabolism has the longest halflife of 1155 days.

Terrestrial field dissipation st udies were conducted in the U. S. (Washington, Utah, and Kansas) and in Europe (Germany, France, and the UK). Both cropped and non-cropped studies were conducted. Leaching of propoxycarbazone-sodium wa s not observed below the 6- to 12- inch layer. Volatilization was not measured, but was not expected based on th e low vapor pressure. Run-off was not measured. Field dissipation half -lives were in the range of 12 to 56 days.

3.2.1.3. Transformation Products

Major identified environmental degradates of propoxycarbazone are saccharin (MKH 7284), MKH 6561 sulfonamide methyl ester, N-me thyl propoxy triazolinone (MKH 7017), 4-hydroxy saccharin, MKH 6561 carboxylic acid (MKH 8394), MKH sulfonamide acid (MKH 7283), Nmethyl propoxy triazolinones amid e, and carbon dioxide. The chemi cal names, structures, routes of formation, and maximum am ounts formed are listed in Table 3.3

.

The propoxycarbazone-carboxylic acid degradate (MKH 8394) results from the loss of a methyl ester group but has the intact sulf onylurea (SU) bridge. This degradate was st able in aerobic and anaerobic aqueous metabolism studi es, forming 50% or more of th e applied test compound at the end of 100-day or 365- day experiments.

There are two sets of degradates that result fro m the cleaving of the SU bridge. These include the triazolinones, and the sulfonamide/saccharins. The former set includes N-methyl propoxy triazolinone amide and N-methyl propoxy tr iazolinone (MKH 7017), which was a major degradate in all soil me tabolism studies. The latter set includes MKH 6561 sulfonamide methyl ester (STJ 4934), sulfonamide acid (M KH 7283), saccharin (MKH 7284), and 4- hydroxysaccharin. All of these we re major metabolites in soil or aquatic metabolism experiments. With the exception of 4-hydroxysacchari n, all are of equal or greater mobility than the parent compound.

Acute toxicity tests were performed with tw o of propoxycarbazone-sodium's major degradates, MKH 6561 carboxylic acid (MKH 8394) and N-me thyl propoxy triazolinone (MKH 7017), and the LC 50 s from these studies were determined to be greater than the limit concentration for both freshwater fish and invertebrates (see Section 3.3.1 for details on the toxicity tests). The same degradates, MKH 8394 and MKH 7017, were tested on vascular and non-vascu lar aquatic plants and determined to be at least two orders of magnitude less toxic than the parent compound. Toxicity data on the other ma jor degradates MKH 6561 sulfonamid e methyl ester (STJ 4934), sulfonamide acid (MKH 7283), saccharin (MKH 7284) , and 4-hydroxysaccharin either are not available or indicate that they are not of concern. 4

4 Acute toxicity studies were condu cted on the earthworm for MKH 7284 (1,2-benzoisothiazol-3-(2H)-one,1,1- dioxide) and STJ 4934 (2-carbomethyoxybenxenesulfonamide) (MRID 45012836 and 45012835). Median lethal concentrations were greater than 1000 mg/kg for both metabolites and the parent compound.-Page 19 of 66- Degradates that do not contain th e triazolinone moiety are not cons idered stressors of concern in this assessment based on the lack of structural similarity to th e parent compound. Degradates that do contain the triazolinone moiety are not considered stressors of concern in this assessment based on results of the toxicity studies descri bed above. While the tria zolinone degradates do appear to be more toxic to fr eshwater aquatic invertebrates th an the parent compound, the acute toxicity endpoints are non-defi nitive for both the degradat es and the parent compound. Additionally, EECs for the parent compound are at le ast four orders of ma gnitude less than the minimum possible toxicity values for fish and a quatic invertebrates and are not expected to be significantly higher if the triazoli none degradates were included. Therefore, risks are evaluated based on estimated exposure to the pare nt compound only in this assessment.-Page 20 of 66-Table 3.3. Propoxycarbazone-sodium and Its Environmental Transformation ProductsCode Name/ SynonymChemical NameChemical StructureStudy TypeMRIDMaximum%AR (day)Final %AR(study length)PARENTPropoxycarbazonesodiumMKH 6561Methyl 2-(4,5-dihydro-4-methyl-5-oxo3-propoxy-1H-1,2,4-triazol-1-yl)carboxamidosulfonylbenzoate, sodiumsaltCAS Reg. No.181274-15-7 (sodium salt);145026-81-9 (acid)Formula: C15H18N4O7S NaMW: 420 g/mol (sodium salt)398 g/mol (acid, MKH 5554)MAJOR TRANSFORMATION PRODUCTSSaccharinMKH 72841,2-Benzisothiazol-3(2H)-one,1,1-dioxideFormula: C7H5NO3SMW: 183 g/molHydrolysis45012733450127401.19% (30 d)@ pH 43.26% (30 d)@ pH 73.78% (30d)@ pH 91.19% (30 d)@ pH 43.26% (30 d)@ pH 73.78% (30d)@ pH 9Photodegradation onsoil45012729 4.7% (18 d) 4.7% (18 d)Photolysis 4501270222.26% (19 d) 22.26% (19 d)Aerobic soil45012720450127361.4% (88 d) 1.4% (361 d)450127224501273626.6% (14 d) 15.6% (180 d)MKH 6561 sulfonamidemethyl esterSTJ 49342-carbomethoxybenzene-sulfonamideFormula: C8H9NO4SMW: 215 g/molHydrolysis450127334501274016.61% (30 d) 16.61% (30 d)Photolysis 45012702 5.8% (7 d) 4.165 (19 d)Photodegradationon soil45012729 9.7% (11 d) 8.7% (18 d)Aerobic soil45012720450127364.1% (13 d) < 0.5% (163 d)450127224501273620.9% (6 d)4.6% (180 d)Aerobic Aquatic 4501270411.3% (100 d) 11.3% (100 d)-Page 21 of 66-N-methyl propoxytriazolinoneMKH 70173H-1,2,4-Triazol-3-one, 2,4-dihydro-4-methyl-5-propoxyFormula: C6H11N3O2MW: 157 g/molHydrolysis450127244501272513.92% (33 d)@ pH 44.15% (33 d)@ pH 74.72% (33 d)@ pH 913.92% (33 d)@ pH 44.15% (33 d)@ pH 74.72% (33 d)@ pH 9Photolysis 4501270313.6% (19 d) 13.6 % (19 d)Photodegradationon soil45012728 8.57% (18 d) 8.57% (18 d)Aerobic soil4501272328.7% (365 d) 28.7% (365 d)450127214501273532% (28 d)43.9% (29 d)55.2% (182 d)14% (182 d)19.9% (182 d)55.2% (182 d)Anaerobic Aquatic 4501270820.5% (196 d) 15.1% (365 d)Aerobic Aquatic 4501270434.4% (100 d) 34.4% (100 d)4-Hydroxy Saccharin1,2-Benzisothiazol-3(2H)-one,4-hydroxy-,1,1-dioxideFormula: C7H5NO4SMW: 199 g/molAerobic soil450127204501273613.8% (361 d) 13.8% (161 d)450127224501273621.9% (180 d) 21.9% (180 d)MKH 6151 CarboxylicAcidMKH 8394Benzoic acid, 2-(((4,5-dihydro-4-methyl-5-oxo-3-propoxy-1H-1,2,4-triazol-1-yl) carbonyl)amino)sulfonylFormula: C14H16N4O7SMW: 384 g/molAerobic soil45012720450127361.2% (88 d) 0.5% (361 d)45012722450127363.7% (180 d) 3.7% (180 d)Anaerobic Aquatic4501270887.8% (90 d) 76.1% (365 d)4501270784.9% (120 d) 68.8% (365 d)Aerobic Aquatic 4501270471.6% (62 d) 48.3% (100 d)-Page 22 of 66-Boldedvalues are those >10%, indicating a major degradate.ND=not detectedMKH 6151 SulfonamideAcidMKH 7283Benzoic acid, 2-(aminosulfonyl)Formula: C7H7NO4SMW: 201 g/molAerobic soil45012722450127365.0% (14 d) ND (180 d)Anaerobic Aquatic 4501270724.6% (365 d) 24.6% (365 d)Aerobic Aquatic 4501270419.4% (100 d) 19.4% (100 d)N-Methyl propoxytriazolinones amide3H-1,2,4-Triazol-3-one-2-carboxamide2,4-dihydro-4-methyl-5-propoxyFormula: C7H12N4O3MW: 200 g/molAerobic soil4501272316.1% (313 d) 16% (365 d)45012721450127358% (93 d) 7.1% (182 d)-Page 23 of 66- 3.2.2. Measures of Aquatic Exposure

3.2.2.1. Aquatic Exposure Modeling

The EECs for propoxycarbazone-sodium in surface water were generated based on maximum use rates ( Table 3.1) . Simulations were conducted us ing the SWCC model (v 1.106, May, 2014). The SWCC simulates pesticide runoff from a treated area to an adjacent water body following applications, in addition to loadings that occur directly to the water as a consequence of spray drift. The SWCC scenarios assume a standard 1-hectare, 2-meter dept h pond (static water body) into which a 10-hectare field drains (see http://www.epa.gov/oppefed1/models/water/ ). An example of SWCC model inputs and output is included in Appendix A.

The SWCC uses the Pesticide Root Zone M odel (PRZM v5.0+, May 6, 2014) and the Varying Volume Water Body Model (VVWM, May 6, 2014, a replacement for the older EXAMS model). The PRZM modeling scenario is the basic file th at describes the local or regional climatological information, soil hydrology, soil characteristics, cr op characteristics, and the pesticide properties necessary to determine pesticide loadings to surfa ce water. This basic file constitutes the first part of the “exposure scenario.” It simulates the processe s in the agricultural fi eld, such as runoff and erosion, on a daily time step. The runoff an d erosion flux output data from PRZM are used as chemical loadings to the VVW M, which simulates surface water, in order to predict the EECs. The VVWM is conceptually similar to the cu rrent EXAMS-based mode l in that both are 2- compartment models driven by firs t-order processes. It simulates the U.S. EPA standard water bodies (i.e. , farm pond) but with greater efficiency and flexibility for incorporation into a user interface. The VVWM also allows for variations in water body volume on a daily basis due to runoff, precipitation, and evapor ation. Temperature, wind speed s, and pesticid e dissipation processes are also allowed to va ry daily. EECs were determined using the standard pond scenario which describes a vulnerable surface waters scen ario for the VVWM component of the modeling exercise.

3.2.2.2. Aquatic Modeling Inputs

For aquatic exposure, modeling was conducted for parent propoxycarbaz one-sodium only. Halflives used for modeling are presented in Table 3.4 . Application parameters were chosen based on the likely method of application at the maximu m application ra te as indicated in the label instructions. Chemical propert y and model input values ( Table 3.4 ) were chosen a ccording to the current Input Parameter Guidance (USEPA, 2009c).

Based on the maximum labeled application rates ( Table 3.1 ), modeling was conducted for three maximum annual rate scen arios: (1) a single app lication rate of 0.0525 lb a.i./A for agricultural fallow/conservation reserve, past ures, and rangeland, (2) a fall application of 0.02625 lb a.i./A, followed by a spring application of 0.02625 lb a.i. /A for wheat, and (3) a fall application of 0.0395 lb a.i./A in the fall followed by 0.0130 lb a.i./A in the spring for wheat. Pesticide application inputs are presented in Table 3.5

.

The scenarios listed in Table 3.6 are those currently approved fo r Tier II surface water modeling which most closely represent the current and pr oposed uses for propoxycarbazone-sodium. There are two rangeland modeling scenarios in the SWCC database. They are for California rangeland-Page 24 of 66- hay and Texas Barton Springs range. For the wheat and triticale (cereal grains) use sites, two applicable scenarios are available, for North Da kota and Texas. For agricu ltural fallow land, the Florida cabbage scenario is used to mimic the fallow conditions at a potential high rainfall area.

Table 3.4. Environmental Fate Data Used for Propoxycarbazone-s odium Aquatic Exposure Inputs

Parameter Value Source
Molecular Weight (g/mol) 420 C 15 H 17 N 4 O 7 SNa
Water Solubility (mg/L) at 20 o C 42000 Product Chemistry Vapor Pressure (torr) 7.1 x 10 -11

Hydrolysis half-life (days) @pH 7 495 (maximum value) MRID 45012733, 45012740
Aqueous photolysis half-life (days) 93.5 (maximum value) MRID 45012703

Aerobic soil metabolism half-life (days) 107 (upper 90 th percentile on eight values: 77, 103, 21, 16, 83, 8.7, 46.5, and 224) MRID 45012720, 45012736 MRID 45012723, 45012721 MRID 45012735, 45012722
MRID 45012736
Aerobic aquatic metabolism halflife (days) 199 (upper 90 th percentile on four values: 110, 107, 193, and 210) MRID 4512704

Anaerobic aquatic metabolism halflife (days) 1155 MRID 45012708
MRID 45012707

Adsorption coefficients (K d ) 0.4518 (Mean of five values: 0.2504, 0.4968, 0.2239, 0.2134, and 1.0747) MRID 45012634

Table 3.5. Application Information for Propoxycarbazone-sodium Aquatic Exposure Inputs Model Input Variable Input Value Comments

Application Date(s) December 1 for California Rangeland Hay April 1 for Texas Barron Spring Range April 1 and November 16 for North Dakota Wheat June 16 and October 1 for Texas Wheat

February 22 for Florida Cabbage Post-emergence (after emergence date)

Fallow – 7 days after harvest

Maximum Application Rate (maximum) and Number of Application 1 @ 0.0525 lb a.i./acre Agricultural fallow/ Conservation reserve, Pasture, and Rangeland

uses 2 @ 0.02625 lb a.i./acre 1 @ 0.0395 lb a.i./acre + 1 @ 0.0130 lb a.i/acre Triticale and Wheat uses

Application method, App. Efficiency / Spray Drift Ground, 0.99 / 0.062 USEPA, 2013 Aerial, 0.95 / 0.125

Table 3.6. SWCC Modeling Scenarios for Propoxycarbazone-sodium

Modeling Scenario Met. File (.dvf) Emergence Date Maturation
Date Harvest Date

California Rangeland Hay 23232 Nov. 1 April 1 May 1 Texas Barton Springs Range 13958 March 1 June 15 Nov. 15 North Dakota Wheat 14914 Oct. 16 April 30 June 17 Texas Wheat 13958 May 16 July 25 August 5 Florida Cabbage 12842 Oct. 16 Feb. 8 Feb. 15-Page 25 of 66- 3.2.2.3. Estimated Environmental Concentrations in Surface
Water

The EECs listed in Table 3.7 reflect daily 1-in-10 year return frequency ( i.e. , “peak”) surface water concentrations based on ma ximum application ra tes for label uses of propoxycarbazonesodium.

Table 3.7. Propoxycarbazone-sodium Screening-level EECs

PRZM Scenario Type of Application 1-in-10-year Peak Exposure ( μ g/L) 1-in-10-year 21-day Average Exposure ( μ g/L) 1-in-10-year 60-day Average Exposure ( μ g/L)

CA Rangeland Hay Aerial 0.847 0.824 0.676

Ground 0.631 0.613 0.490

TX Barton Springs Range Aerial 1.03 0.978 0.934

Ground 0.871 0.826 0.779

ND Wheat (2 @ same rate) Aerial 0.814 0.797 0.755

Ground 0.600 0.587 0.556

ND Wheat (different rates) Aerial 1.00 0.982 0.930

Ground 0.781 0.764 0.723

TX Wheat (2 @ same rate) Aerial 2.29 2.19 2.03

Ground 2.24 2.14 1.98

TX Wheat (different rates) Aerial 1.96 1.82 1.68

Ground 1.88 1.76 1.60

FL Cabbage Aerial 1.08 1.04 0.853

Ground 0.905 0.867 0.697

Bolded values are the maximum EECs for use in risk estimation ( i.e. , RQ calculations).

3.2.2.4. Monitoring Data

Propoxycarbazone is not an analyte in any of the following water monitoring programs: the California Department of Pesticide Regulation (CDPR) surface water database 5 , the USGS NAWQA surface and ground water database 6 , the USEPA STORET Data Warehouse 7 , and the USDA Pesticide Data Program dr inking water monitoring analyses 8

.

3.2.3. Measures of Terrestrial Exposure

3.2.3.1. Ingestion of Foliar Residues by Birds and Mammals

Terrestrial wildlife exposure estimates are typically calculated for birds and mammals, emphasizing a dietary exposure r oute for uptake of pesticide activ e ingredients. Avian exposures

5 http://www.cdpr.ca.gov/docs/emon/surfwtr/surfcont.htm

6 http://cida.usgs.gov/nawqa_queries_public/

7 http://www.epa.gov/storet/

8 http://www.ams.usda.gov/AMSv1.0/ams .fetchTemplateData.do?template =TemplateG&navID=&rightNav1=& topNav=&leftNav=ScienceandLabora tories&page=PDPDownloadData/Repo rts&resultType=&acct=pestcddataprg-Page 26 of 66- are considered surrogates for exposures to terrestrial-phase amphibians and reptiles. For exposure to terrestrial organisms, such as birds and mammals, pesticide resi dues on food items are estimated based on the assumption that organism s forage on areas treated with the pesticide. For propoxycarbazone-sodium, applica tion methods for the registered uses include broadcast and directed spray of liquid formul ations for all use sites.

T-REX (v. 1.5.2) is used to calculate dietary and dose-base d EECs of propoxycarbazone-sodium residues on food items for mammals and birds via proposed spray applications of the labeled uses. Input values for deriving EECs in T-REX are located in Table 3.8 . Upper-bound Kenaga nomogram values are used to de rive EECs for propoxycarbazone-sodi um exposures to terrestrial mammals and birds ( Table 3.9 ), based on a 1-year time peri od. Consideration is given to different types of feeding strategies for ma mmals, including herbivores, insectivores and granivores. Dose-based exposures are estimated for three weight classes of birds (20 g, 100 g, and 1000 g) and for three weight classes of mammals (15 g, 35 g, and 1000 g). Chemical specific foliar dissipation half-life data we re not identified, so the defaul t value of 35 days is used in modeling.

Table 3.8. Input Parameters for Deriving Terrestrial EECs for Propoxyc arbazone-sodium Labeled Uses (TREX)

Proposed Use Application Rate (lbs a.i./A) Number of Applications Minimum Reapplication Interval (days) Foliar Dissipation Half-Life (days)

Agricultural Fallow / Conservation Reserve, Pastures, and Rangeland 1 0.0525 1 NA

35 Triticale 0.0395 1 NA

Wheat 1 st : 0.0395
2 nd : 0.0130 2 182 2

1 Terrestrial exposure modeling for these uses is co mbined because the input parameters are identical.

2 The maximum rate in the fall is 0.0395 lbs a.i./A, which can be followed by an application of 0.0130 lbs a.i./A in the spring. For terrestrial exposure modeling, this use pattern is more conservative than two applications at 0.0263 lbs a.i./A. The minimum reapplication interval is not defi ned on the label, but is assumed to be 6 months for modeling purposes based on the seasonal application pattern.

Because of the length of the re-application interv al between the fall and spring applications of propoxycarbazone-sodium to wheat, the second application does not impact the EECs calculated in T-REX. T-REX calculates EECs at the peak re sidue concentration. In the modeled scenario, sufficient degradation occu rs between the first an d second application that the second application does not affect the peak residue concentrations. Therefore, T-REX results and assessment of risk to terrestrial organisms for wheat and triticale us es will be combined in the remainder of this assessment based on the single maximu m 0.0395 lb a.i./A application rate.

Differences in exposures between ground and aeria l applications are not assessed with the current model. Therefore, terrestrial risk conclu sions for the registered uses apply to both ground and aerial exposures resulting from applicatio n of propoxycarbazone-sodium. An example of output from the T-REX m odel is provided in Appendix B

.-Page 27 of 66- Table 3.9. T-REX Calculated EECs as Food Resi dues for Terrestrial Animals from Propoxycarbazonesodium Labeled Uses

Food Type Dietary-Based EEC (ppm) (Mammals and Birds) Dose-Based EEC for Birds (mg/kg-bw) Dose-Based EEC for Mammals (mg/kg-bw)

All Size Classes Small (20 g) Medium (100 g) Large (1000 g) Small (15 g) Medium (35 g) Large (1000 g) Agricultural Fallow / Conservation Reserve, Pastures, and Rangeland Short grass 12.60 14.35 8.18 3.66 12.01 8.30 1.93 Tall grass 5.78 6.58 3.75 1.68 5.51 3.81 0.88 Broadleaf plants 7.09 8.07 4.60 2.06 6.76 4.67 1.08 Fruits/pods 0.79 0.90 0.51 0.23 0.75 0.52 0.12 Arthropods 4.94 5.62 3.21 1.43 4.71 3.25 0.75
Seeds 0.79 0.20 0.11 0.05 0.17 0.12 0.03
Triticale and Wheat Short grass 9.48 10.80 6.16 2.76 9.04 6.25 1.45 Tall grass 4.35 4.95 2.82 1.26 4.14 2.86 0.66 Broadleaf plants 5.33 6.07 3.46 1.55 5.08 3.51 0.81 Fruits/pods 0.59 0.67 0.38 0.17 0.56 0.39 0.09 Arthropods 3.71 4.23 2.41 1.08 3.54 2.45 0.57
Seeds 0.59 0.15 0.09 0.04 0.13 0.09 0.02

3.2.3.2. Exposure to Insect Pollinators

The Guidance for Assessing Pesticide Risks to Bees (USEPA et al. , 2014) provides equations for the calculation of EECs for bees. The Tier I ex posure method is intended to account for the major routes of pesticide exposure that are relevant to bees ( i.e. , through diet and contact). Exposure routes for bees differ based on application type. Bees foraging in a field treated with a pesticide through foliar spray, su ch as propoxycarbazone-sodium, could potentially be exposed to the pesticide through direct spray as we ll through consuming contaminated food. Foraging honey bees may also be exposed to pesticides via consumption of water from surface water, puddles, dew droplet formation on leaves and guttation fluid; however, the Tier I exposure method does not include quantificatio n of exposures via these routes.

The EECs for foliar applications of pr opoxycarbazone-sodium ar e calculated below. 9

Adult Contact EEC = 0.0525 lbs a.i./A * 2.7 μg a.i./bee = 0.14 μg a.i./bee

Adult Dietary EEC = 0.0525 lbs a.i./A * 110 μg a.i./g * 0.292 g/day = 1.7 μg a.i./bee/day

Larval Dietary EEC = 0.0525 lbs a.i./A * 110 μg a.i./g * 0.124 g/day = 0.72 μg a.i./bee/day

Further analysis of potential exposure routes to honey bees will be considered following the receipt of additional data (see Section 8 ).

9 Based on food consumption rates for larvae (0.124 g/day) and adult (0.292 g/day) worker bees and concentration in pollen and nectar.-Page 28 of 66- 3.2.3.3. Runoff and Spray Drift to Terrestrial and Semi-Aquatic
Plants

Exposure of non-target terrestria l and semi-aquatic (wetland) pl ant species is estimated using OPP’s TERRPLANT (v. 1.2.2) model. Loading via sp ray drift to dry, non-target, adjacent areas is assumed to occur from one acre of treated land to one acre of the non-target area. Runoff is also expected to be a source of pesticide lo ading to non-target areas. TERRPLANT calculates EECs as a function of application rate, solubility, and default assu mptions regarding spray drift. The default spray drift assumptions are: 1% of the application rate (mass per acre) for ground spray applications and 5% for aerial spray applications (USE PA, 2006). The EECs for terrestrial and semi-aquatic plants for a single applicat ion of propoxycarbazone-sodium at the maximum labeled rates for representative uses are presented in Table 3.10 (see example output in Appendix C ).

Table 3.10. EECs for Terrestrial and Semi-Aquatic Plants Near Propoxycarbazone-sodium Use Areas

Crop Single Max. Application
Rate (lbs a.i./A) EECs (lbs a.i./A)

Ground Aerial

Dry
Areas (Total) SemiAquatic

Areas (Total) Spray
Drift Dry
Areas (Total) SemiAquatic

Areas (Total) Spray
Drift

Agricultural Fallow / Conservation Reserve, Pastures, and Rangeland 0.0525 0.0032 0.0268 0.0005 0.0053 0.0289 0.0026

Triticale and Wheat 0.0395 0.0024 0.0201 0.0004 0.0040 0.0217 0.0020

3.3. Ecological Effects Characterization

The ecological effects characterization for prop oxycarbazone-sodium is based upon registrantsubmitted toxicity data for propoxycarbazone-sod ium TGAI, degradates, and formulations. The most sensitive endpoints used for risk assessment are summ arized briefly in Sections 3.3.1 and
3.3.2 . Ecotoxicity data submitted for propoxycarbaz one-sodium degradates on aquatic organisms indicate that these degradates are approx imately equally or less toxic than parent propoxycarbazone-sodium.

The results of a 2014 review of the Ecological Incident Informa tion System (EIIS) are described
in Section 3.3.3 (USEPA, 2009b). A search of the public ally-available ECOTOX database in November 2014 yielded no data ot her than those obtained from registrant-submitted guideline studies described below.

3.3.1. Aquatic Effects Characterization

3.3.1.1. Toxicity to Aquatic Animals

A summary of data on toxicity to aquatic vertebrates an d invertebrates for technical grade propoxycarbazone-sodium and transfor mation products is presented in Table 3.11 . All acute-Page 29 of 66- studies on the parent compound were limit tests with no mortality or subletha l effects observed. No effects were observed in a ny of the chronic studies.

The acute studies on propoxycarbazone-sodium degrad ates also showed no mortality or sublethal effects to freshwater fi sh, but did show some effects on daphni ds. Clinical signs of toxicity and approximately 10% immobilization were observe d at the top concentration tested for both metabolites 7017 and 8394.

Table 3.11. Summary of Available Toxicity Data for Aquatic Animals Exposed to Propoxycarbazone-sodium and its Degradates

Taxonomic

Group Study Type Test Substance

(% a.i.) Surrogate Species Toxicity Value measured mg a.i./L (Acute Toxicity Category) MRID and Study
Classification Aquatic Vertebrates

Freshwater fish Acute TGAI (97.7%) Rainbow trout ( Oncorhynchus mykiss ) 96-hr LC 50 >77.2 (Slightly toxic to Practically non-toxic) 45012809 Acceptable

TGAI (98.0%)

Bluegill sunfish ( Lepomis macrochirus ) 96-hr LC 50 >94.2 (Slightly toxic to Practically non-toxic) 45012806 Acceptable

Metabolite 7017 (99.8%) 96-hr LC 50 >98.7 (Slightly toxic to Practically non-toxic) 45012827 Acceptable

Metabolite 8394 (99.8%) 96-hr LC 50 >87.7 (Slightly toxic to Practically non-toxic) 45012828 Acceptable

Chronic (Early-life

Stage) TGAI (97.7%) Fathead minnow ( Pimephales promelas ) 35-d NOAEC = 105 35-d LOAEC >105 No effects observed 45012817 Supplemental

Estuarine/ marine fish Acute TGAI (97.7%) Sheepshead Minnow ( Cyprinodon variegatus ) 96-hr LC 50 >108 (Practically non-toxic) 45012810 Supplemental

Chronic No data available Aquatic Invertebrates

Freshwater invertebrates Acute TGAI (97.7%)

Water Flea ( Daphnia magna ) 48-hr EC 50 >107 (Practically non-toxic) 45012808 Acceptable

Metabolite 7017 (99.8%) 48-hr EC 50 >106 (Practically non-toxic) 45012826 Acceptable

Metabolite 8394 (99.8%) 48-hr EC 50 >94.1 (Slightly toxic to Practically non-toxic) 45012829 Acceptable

Chronic TGAI (97.3%) Water Flea 21-d NOAEC = 106 21-d LOAEC >106 No effects observed 45012802 Acceptable

Estuarine/

marine invertebrates Acute (Shell Deposition) TGAI (95.4%) Eastern Oyster ( Crassostrea

virginica ) 96-hr EC 50 >130 (Practically non-toxic) 45012805 Acceptable

Acute TGAI (95.4%) Mysid Shrimp ( Mysidopsis bahia ) 96-hr LC 50 >146 (Practically non-toxic) 45012804 Acceptable-Page 30 of 66- Taxonomic

Group Study Type Test Substance

(% a.i.) Surrogate Species Toxicity Value measured mg a.i./L (Acute Toxicity Category) MRID and Study
Classification

Chronic TGAI (95.4%) Mysid Shrimp 27-d NOAEC = 123 27-d LOAEC >123 No effects observed 45012801 Supplemental

3.3.1.2. Toxicity to Aquatic Plants

A summary of data on toxicity to aquatic plan ts for technical grade propoxycarbazone-sodium, formulations, and transformati on products is presented in Table 3.12 . The most toxic response observed was in the study of parent propoxycarbaz one-sodium toxicity to the vascular aquatic plant duckweed. The next most sensitive species test ed was green algae, which was two orders of magnitude less sensitive than duckweed. The pr opoxycarbazone-sodium degradates tested were less toxic than the parent to both duckweed an d green algae. The pare nt compound exhibited slight toxicity to blue-green al gae and no toxicity at the concentr ations tested to freshwater or marine diatoms.

Table 3.12. Summary of Available Toxicity Data for Vascular and Nonvascular Aquatic Plants Exposed to Propoxycarbazone-sodium and its Degradates

Taxonomic

Group Study Type Test Substance

(% a.i.) Surrogate Species Toxicity Value measured mg a.i./L (Most Sensitive Endpoint) MRID and Study
Classification

Aquatic plants and algae Vascular TGAI (97.3%)

Duckweed ( Lemna gibba ) 14-d NOAEC = 0.0031 14-d EC 50 = 0.0064 (Biomass) 45012815 Supplemental

Metabolite
7017 (100.3%) 7-d NOAEC = 103 7-d EC 50 > 103

(Frond area) 45012830 Supplemental

Metabolite 8394 (99.8%) 7-d NOAEC = 0.40 7-d EC 50 = 12 (Frond area) 45012822 Acceptable

Nonvascular TGAI (97.3%)

Green Algae ( Pseudokirchneriella subcapitata ) 96-hr NOAEC = 0.53 96-hr EC 50 = 1.57 (Biomass) 45012814 Acceptable

Formulation

(70.7%) 72-hr NOAEC = 0.612 72-hr EC 50 = 4.8

(Cell density) 45012831 Supplemental

Metabolite
7017 (100.3%) 96-hr NOAEC = 99.5 96-hr EC 50 >99.5 (Biomass) 45012833 Acceptable

Metabolite 8394 (99.8%) 72-hr NOAEC <87.8 72-hr EC 50 >87.8

(Cell density) 45012834 Acceptable

TGAI (98.0%) Blue-green Algae (Anabaena flosaquae ) 96-hr NOAEC = 3.26 96-hr EC 50 = 11.3

(Cell density) 45012803 Acceptable-Page 31 of 66- Taxonomic

Group Study Type Test Substance

(% a.i.) Surrogate Species Toxicity Value measured mg a.i./L (Most Sensitive Endpoint) MRID and Study
Classification

TGAI (97.7%) Freshwater Diatom ( Navicula pelliculosa ) 96-hr NOAEC = 111 96-hr EC 50 > 111

(Cell density) 45012807 Acceptable

TGAI (97.3%) Marine Diatom ( Skeletonema

costatum ) 96-hr NOAEC = 134 96-hr EC 50 > 134 (No effects observed) 45012812 Acceptable

3.3.1.3. Degradate Toxicity

No toxic effects were observe d in acute studies of propoxy carbazone-sodium parent or degradates MKH 7017 and MKH 8394 on freshwater fish up to the limit con centration of 100 mg a.i./L. The degradates tested may therefore be more, less, or equally toxic as the parent compound. However, they are not in cluded as stressors of concern due to the lack of observable adverse effects at the limit concentration.

For freshwater invertebrate s, no toxicity was observed in acute studies with the parent compound up to the limit concentration, but slight toxicity (10% imm obilization observed at the top concentration) was observed for both degr adates tested, MKH 7017 and MKH 8394. This indicates that the triazolinone degradates may be more toxic than the parent to freshwater invertebrates. However, the acute toxicity endpoin ts for the degradates were still greater than the limit concentration and therefore the degradates are not considered stressors of concern.

In toxicity studies on vascul ar and non-vascular aquatic pl ants the propoxycarbazone-sodium degradates MKH 7017 and MKH 8394 were at least two orders of ma gnitude less toxic than the parent compound. Therefore, these degradates ar e not included as stre ssors of concern for aquatic plants.

See Section 3.2.1.3 for additional discussion of the propoxycarbazone-sodium degradates.

3.3.2. Terrestrial Effects Characterization

3.3.2.1. Toxicity to Terrestrial Animals

A summary of data on toxicity to birds, mammal s, and terrestrial invertebrates for technical grade propoxycarbazone-sodium, fo rmulations, and transformation products is presented in
Table 3.13

.

In the avian acute oral and sub-acute dietary st udies, the only adverse ef fects observed were in the acute oral study with the canar y. The canary exhibited clinical signs of toxicity and transient effects to body weight change at the limit dose, but all birds fully recovered by day 2 of the study and the limit dose was determined to be greater than 10 times the highest avian EEC. In the avian reproduction studies, statistically significant effects on reproductive endpoints were observed for both the bobwhite quail and mallard duck at the highest treatment concentrations.-Page 32 of 66- No mortality or clinical signs of toxicity were observed in acute oral or acute inhalation studies with the rat. The 2-generation reproduction study with the ra t showed effects on reproduction and offspring, including post implantation loss and decreased litter size.

Acute contact honey bee studies with the TGAI and a formulation showed no effects up to the limit dose. Acute oral honey bee st udies with the TGAI showed some clinical signs of toxicity after 4 hours of exposure, but no si gnificant effects on mortality. Th ese effects were not seen in the acute oral honey bee study with the formulati on. Additional toxicity da ta for honey bees will allow for a more thorough hazard assessment (see Section 8 ). No effects were observed in studies on earthworms including acu te and chronic studies with the TGAI, degradates, and formulations.

Table 3.13. Summary of Availabl e Toxicity Data for Terrestrial An imals Exposed to Propoxycarbazonesodium

Taxonomic

Group Study Type Test Substance Surrogate Species Toxicity Value
measured a.i. (Acute Toxicity Category) MRID and Study
Classification

Birds Acute Oral TGAI (97.7%) Bobwhite quail ( Colinus virginianus ) LD 50 >2,000 mg/kg-bw (Practically non-toxic) 45012813 Acceptable

TGAI (97.7%) Canary ( Serinus
canaria ) LD 50 >2,000 mg/kg-bw (Practically non-toxic) 49072701 Acceptable

Sub-acute

dietary TGAI (97.7%) Bobwhite quail LC 50 >10,566 mg/kg-diet (Practically non-toxic) 45012816 Acceptable

TGAI (99.9%) Mallard duck ( Anas platyrhynchus ) LC 50 >10,339 mg/kg-diet (Practically non-toxic) 45012821 Acceptable

Chronic TGAI (97.7%) Bobwhite quail NOAEC = 324 mg/kg-diet LOAEC = 999 mg/kg-diet

Decreased eggs laid/pen 49072702 Acceptable

TGAI (96.3%) Mallard duck NOAEC = 268 mg/kg-diet LOAEC = 1260 mg/kg-diet Decreased viable embryos, hatchlings, & survivors/eggs

set, and eggshell thickness 45012832 Acceptable

Mammals 1 Acute Oral TGAI (97.8%)

Laboratory rat ( Rattus norvegicus ) LD 50 >5,000 mg/kg-bw (Practically non-toxic) 45012509 Acceptable

Acute Inhalation TGAI (97.8%) LC 50 > 5.03 mg/L (Toxicity Category IV - Low) 45012505 Acceptable

Chronic (2- generation reproduction) TGAI (97.6%) NOAEC=297 mg/kg-bw/day LOAEC=1231 mg/kg-bw/day

Increased post-implantation loss; Decreased F2 litter size 45012529 Acceptable

Insects Acute

contact TGAI (96.9%)
Honey bee ( Apis mellifera ) 48-hr LD 50 >200 μ g/bee (Practically non-toxic) 45012818 Acceptable

Formulation

(70.7%) 48-hr LD 50 >200 μ g/bee (Practically non-toxic) 45012838 Acceptable

Acute oral TGAI (96.9%) 48-hr LD 50 >319 μ g/bee (Practically non-toxic) 45012818 Supplemental-Page 33 of 66- Taxonomic

Group Study Type Test Substance Surrogate Species Toxicity Value
measured a.i. (Acute Toxicity Category) MRID and Study
Classification

Formulation

(70.7%) 48-hr LD 50 >402 μ g/bee (Practically non-toxic) 45012838 Supplemental

Soil invertebrates Acute TGAI (96.6%)

Earthworm ( Eisenia fetida ) LC 50 > 1,000 mg/kg-diet 45012825 Supplemental

Metabolite 7284 (99.4%) LC 50 > 1,000 mg/kg-diet 45012835 Supplemental

Metabolite
STJ 4934 (99.9%) LC 50 > 1,000 mg/kg-diet 45012836 Supplemental

Chronic Formulation (70.7%) NOAEC = 0.31 lb/A LOAEC >0.31 lb/A No effects observed 45012837 Supplemental

1 Mammalian toxicity endpoints for propoxycarbazone-sodium provided and reviewed by the U.S. EPA Office of Pesticide Programs Health Effects Division (HED).

3.3.2.4. Toxicity to Terrestrial Plants

A summary of data on toxicity to terrestrial pl ants for a propoxycarbazone -sodium formulation is presented in Table 3.14 . Consistent with the herbicidal m ode of action, terrestrial plants are sensitive to propoxycarbazone-sod ium exposure. The most sensitive monocot was onion and the most sensitive dicot was canola in both the s eedling emergence and vege tative vigor studies.

Table 3.14. Summary of Available Toxicity Data for Terrestrial Plan ts Exposed to Propoxycarbazonesodium 70WG Formulation

Type of Study Species Crop IC 25 (lbs a.i./A) NOAEC
or IC 05 (lbs a.i./A) Most Sensitive Endpoint MRID and Study
Classification Seedling Emergence

Monocots Corn 0.0070 0.0067 Dry weight

45012823 Acceptable Rye 0.0014 0.00084 Dry weight Oat 0.0088 0.0067 Shoot height
Onion 0.00045 0.000034 Dry weight

Dicots Flax >0.013 0.013 None Soybean >0.013 0.013 None Sunflower 0.012 0.0060 Dry weight Sugar beet 0.0020 0.0017 Dry weight

Canola 0.00058 0.00021 Dry weight Buckwheat 0.012 0.0035 Dry weight Vegetative Vigor

Monocots Corn 0.0017 0.00070 Dry weight

45012823 Acceptable Rye 0.0029 0.00052 Dry weight Oat 0.00098 0.00031 Dry weight
Onion 0.00065 0.000063 Dry weight

Dicots Flax 0.0055 0.0017 Shoot height Soybean 0.0037 0.00084 Shoot height Sunflower 0.0025 0.00084 Shoot height Sugar beet 0.00089 0.00084 Dry weight

Canola 0.00049 0.00021 Shoot height Buckwheat 0.0012 0.00039 Shoot height-Page 34 of 66- Bolded values are the most sensitive endpoints that are used for risk estimation ( i.e. , RQ calculations)

3.3.3. Review of Incident Data

The Ecological Incident In formation System (EIIS)
, which is maintained by the Agency’s Office of Pesticide Programs, was searched to determin e if ecological incidents have been reported for propoxycarbazone-sodium. Based on a search of EIIS conducted in November 2014, the Agency has received 30 reports of adverse field effects to non-target plants that have been linked to the use of propoxycarbazone-sodium. All of these inci dents involved damage to spring or winter wheat. In 27 incidents, the damaged crop was tr eated directly with a propoxycarbazone-sodium product. One incident was attributed to drift or runoff from an adjacent field and two did not report the route of exposure. The Agency co nsidered the likelihood that propoxycarbazonesodium was the cause of the incidents as unlikely in one case, possible in 21 cases, and probable in eight cases.

The American Bird Conservancy Avian Incident Monitoring System was searched in November 2014 and returned no records of incidents associated with propoxycarbazone-sodium 10

.

Based on a search of the U.S. EP A Office of Pesticide Programs Incident Data System (IDS), which compiles aggregate incidents, there were a total of 36 incidents involving propoxycarbazone-sodium be tween 2005 and 2013, all of which were associated with minor plant damage.

A lack of reported incidents does not necessarily m ean that such incidents have not occurred. In addition, incident reports for non -target plants and animals t ypically provide information on acute mortality events only. Reports for other adverse effects, such as reduced growth or impaired reproduction, are rarely received.

4. Risk Characterization

4.1. Risk Estimation

This screening-level assessment of the labele d uses of propoxycarbazo ne-sodium relies on the deterministic RQ method to provide a metric of potenti al risks. The RQ pr ovides a comparison of exposure estimates to toxicity endpoints ( i.e. , the estimated exposure concentrations are divided by acute and chronic toxicity values, respectiv ely). The resulting unitless RQ values are compared to the Agency’s LOCs. The LOCs, when exceeded, are used by the Agency to indicate when the use of a pesticide, as directed by the la bel, has the potential to cause adverse effects of concern to non-target organisms. For endang ered species, LOC exc eedances require an additional in-depth evaluation of the potential co -occurrence of listed species and areas in which crops are grown to characterize risks.

10 http://www.abcbirds.org/abcprogram s/policy/toxins/aims/aims/index.cfm-Page 35 of 66- 4.1.1. Aquatic Organisms

4.1.1.1. Fish, Amphibians, and Invertebrates

RQ values are not calculated for acute risk to fres hwater or estuarine/marine fish or invertebrates because the available toxicity endpoints for all tested species are non-definitive. Even if these non-definitive endpoints were cons ervatively equated to an EC 50 or LC 50 the RQs would be less than the LOC of 0.05 for listed aquatic species for all species tested. The potential for risk to fish, amphibians, and aquatic i nvertebrates is further discussed in the Risk Description ( Section
4.2 ).

Chronic RQ values for freshwater and estuarine /marine fish and invert ebrates are <0.01 across all labeled uses of propoxycarbazone-sodium and therefore do not exceed the chronic risk LOC (LOC = 1) for aquatic animals. Throughout this screening-le vel assessment, conclusions for freshwater fish are assumed to a pply to aquatic-phase amphibians.

4.1.1.3. Aquatic Plants

Table 4.1 presents RQ values calculated for aqua tic plants exposed to propoxycarbazone-sodium residues in surface water based on the most sensi tive toxicity data for the TGAI. The RQs do not exceed the LOC (LOC = 1) for listed or non-liste d aquatic vascular or non-vascular plants for any registered uses. The SWCC modeling scenarios that resulted in the highest EECs for each use ( Table 3.7 ) are used for the RQ calculations.

Table 4.1. RQ Values for Aquatic Plants from Exposure to Propoxycarbazone-sodium TGAI

Taxonomic

Group Listed
Status Toxicity Endpoint (mg a.i./L) RQ Values for Labeled Uses 1
Triticale, Wheat

(EEC = 2.29 μ g/L) Agricultural
Fallow/CRP Land (EEC = 1.08 μ g/L) Pasture, Rangeland (EEC = 1.03 μ g/L)

Vascular aquatic plants Non-listed EC 50 = 0.0064 0.36 0.17 0.16

Listed NOAEC = 0.0031 0.74 0.35 0.33

Non-vascular aquatic plants Non-listed EC 50 = 1.57 0.0015 0.0007 0.0007

Listed NOAEC = 0.53 0.0043 0.0020 0.0019

1 RQ=EEC/toxicity endpoint.

4.1.2. Terrestrial Organisms

4.1.2.1. Birds and Mammals

RQ values are not calculated for acute risk to birds on a dose or dietary exposure basis because the available toxicity endpoints for bobwhite quail, mallard duck, and canary are non-definitive. Similarly, RQ values are not calculated for acute risk to mammals because the available toxicity endpoint for the laboratory rat is non-definitive. Even if thes e non-definitive endpoints were conservatively equated to an LD 50 or LC 50 the RQs would be less than the LOC of 0.1 for listed birds and mammals for all species te sted (see sample T-REX output in Appendix B ). The potential for risk to birds (and therefore to terrestrial-phase amphibians and reptiles) and-Page 36 of 66- mammals is further discussed in the Risk Description ( Section 4.2 ).

Chronic RQ values for birds based upon a NOAEC of 268 mg a.i./kg-diet for the mallard duck range from <0.01 to 0.05 across labeled uses of propoxycarbazone-sodium and therefore do not exceed the chronic risk LOC (LOC = 1) for bird s. Throughout this screening-level assessment, conclusions for birds are assumed to apply to terrestrial-phase am phibians and reptiles.

Chronic RQ values for mammals based on a NOAEC of 297.1 mg a.i./kg-bw/day for the laboratory rat range from <0.01 to 0.02 across la beled uses of propoxycarbazone-sodium and therefore do not exceed the chronic risk LOC (LOC = 1) for mammals.

4.1.2.2. Terrestrial Invertebrates

The acute contact and oral toxicity endpoints for honey bees, which are used to evaluate risk to terrestrial invertebrates, are non-definitive. Theref ore, RQ values are not calculated for acute risk to terrestrial invertebrates. However, even if the EECs are compared to the highest concentrations tested for the hone y bee acute contact and oral studies, the RQs would be almost 100 times lower than the acute ri sk LOC of 0.4 for bees (USEPA et al. , 2014). No toxicity data are available for calculation of chronic RQs for adult bees or for acute or chronic RQs for bee larvae. Further analysis will be conducted following receipt of these additional data (see Section
8 for details).

4.1.2.3. Terrestrial Plants

The RQs for listed and non-listed terrestrial plants, including monocots and dicots, exceed the LOC (LOC = 1) for almost all exposure scenarios modeled in TERRPLANT (see Table 4.2 ). The only exception is for non-listed plants exposed to spray drift only for ground applications to triticale and wheat. However, updated spray drift da ta demonstrates that the default spray drift assumptions in TERRPLANT are lower than w ould be expected (USEPA, 2013). With the revised spray drift fraction of 6% for ground app lications, the RQs would exceed the LOC for all scenarios.

Table 4.2. RQs for Terrestrial Plants Inhabiting Dry and Semi-Aquatic Areas Exposed to Propoxycarbazonesodium via Runoff and Drift

Type of Plant Ground spray Aerial Spray

Dry Areas SemiAquatic

Areas Spray Drift Only Dry Areas SemiAquatic

Areas Spray Drift Only

Agricultural Fallow/Conservation Reserve, Pastures, Rangeland 0.0525 lb a.i./A

Monocot Nonlisted 7.0 60 1.2 12 64 5.8

Listed 93 788 15 154 849 77

Dicot Nonlisted 5.4 46 1.1 9.1 50 5.4

Listed 15 128 2.5 25 138 13

Triticale and Wheat 0.0395 lb a.i./A
Monocot Non- 5.3 45 0.88 8.8 48 4.4-Page 37 of 66- listed

Listed 70 593 12 116 639 58

Dicot Nonlisted 4.2 35 0.81 6.8 38 4.0

Listed 11 96 1.9 19 103 9.4

Bolded RQ values exceed the level of concern for risk to plants (LOC = 1).

4.2. Risk Description

4.2.1. Risks to Aquatic Organisms

4.2.1.1. Fish, Aquatic-phase Amphi bians, and Invertebrates

Propoxycarbazone-sodium exhib ited no toxicity to any of the fish or aquatic invertebrate species studied at tested concentrations. No RQs exceeded the LOCs for listed or non-listed aquatic species and no incidents associated with propo xycarbazone-sodium involving aquatic species have been reported to the Agency. While acute RQs could not be calculated due to non-definitive toxicity endpoints, even if these non-definitiv e endpoints were conservatively equated to an EC 50 or LC 50 the RQs would be less than the LOC of 0.05 for listed aquatic sp ecies for all species tested. Freshwater fish are assumed to represen t aquatic-phase amphibians in this assessment. While propoxycarbazone-sodium is a highly solubl e, mobile, and persistent compound, the low toxicity and low application rates result in no acute or chronic risks of concern for aquatic species.

There is some uncertainty in the assessment of risk to aquatic species due to the lack of chronic toxicity data for estuarine/marine fish and the l ack of toxicity data fo r benthic invertebrates. However, due to the consistent lack of observa ble adverse effects acro ss all species for which data are available, these additional data are not expected to change the conclusions. An acute-tochronic ratio cannot be calculated to estimate chronic ri sk to estuarin e/marine fish due to the non-definitive acute toxicity endpoints. Additiona lly, propoxycarbazone-sodium is not expected to partition to sediment due to its low Kow value.

4.2.1.2. Aquatic Plants

Propoxycarbazone-sodium is very highl y toxic to vascular aquatic pl ants and at mo st moderately toxic to the tested species of non-vascular aquatic plants. Howe ver, RQs do not exceed the LOC (LOC = 1) for listed or non-listed aquatic vascular or non-vascular plants for any registered uses. The highest RQ is 0.74 for listed vascular a quatic plants exposed to propoxycarbazone-sodium following use on winter and spring wheat.

This conclusion for listed vascular aquatic plan ts differs from the last risk assessment conducted for use of propoxycarbazone-sodium on pastur e and rangeland (USEPA, 2008). In that assessment, the EC 05 value of 0.002 μ g a.i./L was used to assess risk to listed vascular aquatic plants. However, the toxicity study on duc kweed (MRID 45012815) also provides a NOAEC of
0.0031 μ g a.i./L. Therefore, the NOAEC is used for RQ calculation in this assessment.-Page 38 of 66- 4.2.2. Terrestrial Organisms

4.2.2.1. Birds, Reptiles, and Terrestrial-phase Amphibians

Propoxycarbazone-sodium is practically non-toxic on an acute ba sis to all avian species tested. No toxic effects were observed in acute and sub- acute studies with the bobwhite quail or mallard duck. The canary exhibited clinical signs of toxi city and transient effects on body weight change at the limit dose, but a ll birds fully recovered by day 2 of the study and th e limit dose was greater than 10 times the highest avian EEC. Acute RQ valu es are not calculated for avian species due to the non-definitive toxicity endpoints. However, even if these non-definitive endpoints were conservatively equated to an LD 50 or LC 50 the RQs would be less than the LOC of 0.1 for listed birds for all species tested (see sample T-REX output in Appendix B ). The STIR model indicates that inhalation of va por and spray drift is not an e xposure route of concern for birds (see Appendix D ). The SIP model indicates that drinki ng water exposure may be a potential pathway of concern for wildlife due to the high solubility of propoxycarbazone-sodium (42,000 mg/L); however, risks are unlikely due to the non-definitive toxic ity endpoints for both birds and mammals and low application rates (see Appendix E ). Throughout this screening-level assessment, conclusions for bird s are assumed to apply to terrestrial-phase amphibians and reptiles.

In the avian reproduction studies, statistically significant effects on re productive endpoints were observed for both the bobwhite quail and mallard duc k at the highest treatment concentrations. Chronic RQ values calculated using these endpoin ts do not exceed the chronic risk LOC of 1 for listed and non-listed birds.

No incidents associated with propoxycarbazo ne-sodium involving avian species have been reported to the Agency.

4.2.2.2. Mammals

No mortality or clinical signs of toxicity were observed in acute oral study with the rat. Acute RQ values are not calculated fo r mammals due to the non-defini tive toxicity endpoint. However, even if this non-definitive endpoint was conservatively equated to an LD 50 the RQs would be less than the LOC of 0.1 for listed mammals (see sa mple T-REX output in Appendix B ). Additionally, no mortality or clin ical signs of toxicity were observed in the acute inhalation study with the rat, and the STIR model indicates th at inhalation of vapor and spray drift is not an exposure route of concern for mammals (see Appendix D ).

The 2-generation reproduction st udy with the rat showed eff ects on reproduction and offspring, including post implantation loss and decreased litter size. Chronic RQ values based on these endpoints do not exceed the chronic risk LOC of 1 for listed and non-listed mammals.

No incidents associated with propoxycarbazone-s odium involving mammals have been reported to the Agency.-Page 39 of 66- 4.2.2.3. Terrestrial Invertebrates

Acute contact honey bee studies with the TGAI and a formulation showed no effects up to the limit dose. Acute oral honey bee st udies with the TGAI showed some clinical signs of toxicity after 4 hours of exposure, but no si gnificant effects on mortality. Th ese effects were not seen in the acute oral honey bee study with the formul ation. Because the endpoi nts from these studies are non-definitive, RQ values are not calculated for acute risk to terrestrial invertebrates. However, even if the EECs for honey bees are co mpared to the highest concentrations tested in the submitted honey bee acute contact and oral st udies, the RQs would not exceed the acute risk LOC of 0.4 for bees (USEPA et al. , 2014).

There is uncertainty regarding the potential acute and chronic effects of the compound on honey bee larvae as well as potentia l for chronic effects on adult be es. Since propoxycarbazone-sodium is a systemic herbicide, residues may be present in pollen and/or nectar and represent a route of exposure for bees through both contact and ingesti on. Therefore, there is uncertainty with respect to the likelihood of adverse effect s from acute or chronic exposure of larval bees to residues that may be translocated to pollen or nectar. While wheat and tritic ale are not pollinator-attractive crops, spray drift and runoff from these uses may result in propoxycarbazone-sodium exposure to non-target blooming plants. Additionally, pollinator attractive crops may be present on pasture, rangeland, and Conservation Reserve Program land treated with propoxycarbazone-sodium. Therefore, additional data on pollinators is needed to fully characterize the risk associated with propoxycarbazone-sodium use to all developmental stages of honey bees, as sensitivity may vary according to life-stage and le ngth of exposure (adul t vs. larval and acute vs. chronic, respectively). These data are required under the Guidance for Assessing Pes ticide Risks to Bees (USEPA et al. , 2014). See Section 8 for additional details.

No effects were observed in studi es on earthworms incl uding acute and chroni c studies with the TGAI, degradates, and formulations.

No incidents associated with propoxycarbazone-sodi um involving terrestrial invertebrates, such as bee kills, have been reported to the Agency.

4.2.2.4. Terrestrial Plants

Consistent with the herbicidal mode of action, propoxycarbazone-sodium exhibits toxicity to terrestrial plant species. Both monocots and dicots were affe cted by propoxycarbazone-sodium in the seedling emergence and vegetativ e vigor studies. The RQs for li sted and non-list ed terrestrial plants, including monocots and dicots, exceed th e LOC of 1 for almost all modeled exposure scenarios, including aerial and gr ound applications for all regist ered uses. The only exception is for non-listed plants exposed to spray drift onl y for ground applications to triticale and wheat. However, updated spray drift data demonstrates that the default spray drift assumptions in TERRPLANT are lower than would be expected (USEPA, 2013). With the revised spray drift fraction of 6% for ground applications, the RQs would exceed the LOC for all scenarios.-Page 40 of 66- The Agency has received 30 individual reports of adverse field effects to non-target plants that have been linked to the use of propoxycarbazone-s odium and an additional 36 aggregated reports of minor plant damage. All of the 30 incidents with detailed reports involved damage to spring or winter wheat. The damaged crop was treated directly with propoxycarbazone-sodium in the majority of the incidents, however one incident was attributed to drift or runoff from an adjacent field.

Spray Drift

Non-target terrestrial plant species could be impacted by exposure to propoxycarbazone-sodium via spray drift in areas adjacent to treated fields . The distances from the treated fields at which non-target plants may be affect ed due to spray drift are calc ulated using AgDRIFT v2.1.1 and are presented in Table 4.3 below. AgDRIFT input parameters were selected using EFED’s Guidance on Modeling Offsite Deposition of Pesticides via Spray Drift for Ecological and Drinking Water
Assessments (USEPA, 2013). High boom he ight (50 in or 4.2 ft) fo r ground applications is consistent with the labeled height restriction of 4 ft above the crop cano py. Labels for all end-use products with the exception of Olympus® 70% WDG specify medium droplet sizes. The Olympus® 70% WDG label specifies a coarse droplet size. Therefor e, the fine to medium/coarse drop size distribution (DSD) was modeled for ground applications, and both the fine to medium DSD and the medium to coarse DSD categories were modeled for aerial applications.

A spray drift buffer for aerial appl ications would need to be >1,000 ft to reduce ri sks to listed plants below levels of concern for all registered uses. For ground applications, spray drift buffer distances for listed plants range from 150 to 200 ft for dicots and 530 to 700 ft for monocots. For non-listed plants, buffer di stances are reduced (see Table 4.3 ). The most sensitive endpoints from the vegetative vigor study were used fo r these calculations (monocot: onion NOAEC = 0.000063 lb a.i./A, IC 25 = 0.00065 lb a.i./A; dicot: canola NOAEC = 0.00021 lb a.i./A, IC 25 = 0.00049 lb a.i./A).

Table 4.3. Possible Effects Distance for Nontarget Terrestrial Plants Exposed to Propoxycarbazone-sodium through Spray Drift Only Based on the Most Sensitive Crop Species

Type of Plant Buffer Distance for Ground Spray 1 (ft) Buffer Distance for Aerial Spray 2 (ft)

Fine to Medium/Coarse DSD Fine to Medium DSD Medium to Coarse DSD Agricultural Fallow/Conservation Reserve, Pastures, Rangeland 0.0525 lb a.e./A

Monocot Non-listed 50 900 350 Listed 700 >1,000 >1,000

Dicot Non-listed 70 >1,000 450 Listed 200 >1,000 >1,000

Triticale and Wheat 0.0395 lb a.i./A

Monocot Non-listed 40 580 275 Listed 530 >1,000 >1,000

Dicot Non-listed 50 900 350 Listed 150 >1,000 >1,000

1 Ground buffer distances are calculated using high boom height (50 in) and ASAE Fine to Medium/Coarse Drop Size Distribution (DSD). Default AgDRIFT Tier I parameters are used for all other settings.

2 Aerial buffer distances are calculated using both ASAE Fine to Medium DSD and Medium to Coarse DSD. Default AgDRIFT Tier I parameters are used for all other settings.-Page 41 of 66- Four of the five currently registered e nd-use products (all products except for Olympus TM Rangeland Herbicide) include the following la bel language rega rding buffers:

To avoid adverse effects on endangered plant species, the following mitigation measures will be required where endangered species occu r in Counties listed in the table on the following page.

For ground applications, the applicator must:
1. Apply when there is sustained wind aw ay from native plant communities, OR
2. Leave 50 foot untreated buffer between treatment area and native plant communities.

For aerial applications , the applicator must:
1. Apply only when there is sustained wind away from native plant communities, OR
2. Leave 350 foot untreated buffer between treatment area and native plants

Specific counties are listed following this lan guage on three of the f our labels. The buffer distances of 50 ft for ground appli cations and 350 ft for aerial appl ications are smaller than those calculated for the protection of listed, and in most cases non-listed, terrestrial plants ( Table 4.3 ).

Irrigation Water

The use of surface and/or groundwater-derived irrigation water cont aining propoxycarbazonesodium may result in damage to the irrigated crops due to th e compound’s high mobility and potential to persist in aquatic environments. The following equa tion can be used to estimate exposure to terrestrial plants when one inch of surface or ground water contaminated with propoxycarbazone-sodium is appl ied to crops for irrigation. Z mg/L is the concentration in the irrigation water.

EEC lb a.i./Acre = ( Z mg/L ) * (102,790 L water/ Acre-in) * (1 inch) * (1 lb/ 453,592 mg)

Similarly the depth of water applie d to a field that would lead to a potential risk concern can be calculated using the following equation:

X inches = [(EEC or IC 25 in lbs a.i./Acre) *(Acre-in / 102,790 L water) * (453,592 mg/ 1lb)] / (Z mg/L)

The post breakthrough mean gr oundwater concentration mode led in the drinking water assessment conducted for Re gistration Review was 2.8 p pb (PRZM-GW, USEPA, 2014c). Comparing this concentration to the most sensit ive terrestrial plant e ndpoint (seedling emergence canola NOAEC = 0.000034 lb a.i./A, IC 25 = 0.00045 lb a.i./A), 1/20 of an inch of irrigation would be required to cause a risk concern for listed species, a nd 3/4 of an inch of irrigation would be required to cause a risk concern for non-listed speci es. If propoxycarbazone-sodium degrades more quickly below the 1-meter depth than PRZM-GW allows or if it laterally disperses in subsurface soils, the concentrations in irrigation water may be lower and the amount of irrigation water required to cause a risk concern may therefore be higher.-Page 42 of 66- The same equations can be used to estimate th e concentration of propoxycarbazone-sodium in water used for irrigation that would trigger a risk concern for terrestrial plants. Using the most sensitive terrestrial plant endpoints and assuming applicati on of one inch of ir rigation water, the concentrations are 0.15 ppb and 2.0 ppb for listed and non-listed plants, respectively. As the highest peak surface water EEC is 2.29 ppb, risks to terrestrial plants from use of less than 1 inch of surface water contaminated with propoxycarbaz one-sodium for irrigati on purposes could also result in risks of concern for list ed and non-listed te rrestrial plants.

5. Listed Species of Concern

5.1. Evaluating Risks to Listed Species

Consistent with EPA’s responsibility under ESA, the Agency will evaluate risks to federally listed threatened and endangered (listed) species fro m registered uses of pesticides in accordance with the Joint Interim Approach es developed to implement the recommendations of the April 2013 National Academy of Sciences (NAS) report. 11 The NAS report outlines recommendations on specific scientific and tec hnical issues related to the development of pesticide risk assessments that EPA and the U.S. Fish and Wildlife Service and National Marine Fisheries Service (collectively, the Services) must conduct in connection w ith their obligations under the ESA and FIFRA. EPA will address concerns speci fic to propoxycarbazone-sodium in connection with the development of its final Registration Review decision for propoxycarbazone-sodium

.

In November 2013, EPA, the Services, and the U.S. De partment of Agri culture (USDA), released a white paper 12 containing a summary of their join t Interim Approaches for assessing risks to listed species from pesticides. These Interim Approaches were deve loped jointly by the agencies in response to the NAS recommendati ons, and reflect a comm on approach to risk assessment shared by the agencies as a way of addressing scientific di fferences between the EPA and the Services. Details of the joint Interim Approaches are c ontained in the November 1, 2013 white paper.

Given that the agencies are continuing to develop and work toward implementation of the Interim Approaches to assess the potential risks of pesticides to listed species and their designated critical habitat, this preliminary Registration Review risk assessment for propoxycarbazone-sodium doe s not describe the sp ecific ESA analysis , including effects determinations for specific listed species or designated critical habitat. Rather, a screening level assessment is provided below. This will allow EPA to focus its future evaluations on the types of species where the potential for effects exists, onc e the scientific methods being developed by the agencies have been fully vetted. Once the agen cies have fully developed and implemented the scientific methods n ecessary to complete risk assessments for listed speci es and their designated

11 Assessing Risks to Endangered and Threatened Species from Pesticides. Available at: http://www.nap.edu/catalog.php?record_id=18344

12 Interim Approaches for National-Level Pesticide E ndangered Species Act Assessments Based on the Recommendations of the National Academy of Sciences April 2013 Report. Available at: http://www.epa.gov/espp/2013/nas.html-Page 43 of 66- critical habitats, these methods will be applied to subseque nt analyses of propoxycarbazonesodium as part of completi ng this Registration Review.

5.2. Taxonomic Groups Potentially at Risk

Based on this screening-level assessment, there are potential risks of direct effects to listed and non-listed terrestrial plants from the use of propoxy carbazone-sodium on all of its registered use sites. Listed species of all taxa may also be affected through indirect effects because of the potential direct effects on liste d and non-listed terrestrial plants. Potential direct effects on listed and non-listed terrestrial plan ts from the use of propoxycarbaz one-sodium may be associated with modification of primary constituent elements of designated critical habitats, where such designations have been made. Thes e conclusions are summarized in Table 5.1

.

Table 5.1. Potential Effects to Federally-Listed Taxa Associated with Direct or Indirect Effects from the Labeled Uses of Propoxycarbazone-sodium

Listed Taxon Direct Effects Indirect Effects Uses of Concern

Terrestrial and semi-aquatic plants - monocots Yes Yes

Agricultural fallow/ Conservation reserve, Pasture,

Rangeland, Triticale, Wheat Terrestrial and semi-aquatic plants - dicots Yes Yes

Terrestrial invertebrates No Yes Birds No Yes Terrestrial-phase amphibians No Yes Reptiles No Yes Mammals No Yes Aquatic plants No Yes Freshwater fish No Yes Aquatic-phase amphibians No Yes Freshwater invertebrates No Yes
Marine/estuarine fish No Yes
Marine/estuarine invertebrates No Yes

6. Endocrine Disruptor Screening Program

As required by FIFRA and FFDCA, EPA reviews numerous studies to a ssess potential adverse outcomes from exposure to chemicals. Collectiv ely, these studies include acute, subchronic and chronic toxicity, including assessments of carcinogenicity, neurotox icity, developmental, reproductive, and general or systemic toxicit y. These studies include endpoints which may be susceptible to endocrine influe nce, including effects on endocr ine target organ histopathology, organ weights, estrus cyclicity, sexual maturati on, fertility, pregnancy rates, reproductive loss, and sex ratios in offspring. For ecological hazar d assessments, EPA evaluates acute tests and chronic studies that assess growth, developm ental and reproductive effects in different taxonomic groups. As part of its most recent re gistration decision for propoxycarbazone-sodium, EPA reviewed these data and selected the most sensitive endpoints for rele vant risk assessment scenarios from the existing ha zard database. However, as re quired by FFDCA section 408(p), propoxycarbazone-sodium is subject to the endocrin e screening part of th e Endocrine Disruptor Screening Program (EDSP).-Page 44 of 66- 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 effects as the Administrator may designate.” The EDSP employs a two-tiered a pproach to making the 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 thr ough Tier 1 screening and are f ound to have the potential to interact with E, A, or T hormonal systems will proceed to the next stage of the EDSP where EPA will determine which, if any, of the Tier 2 tests are necessary based on the available data. Tier 2 testing is designed to identify any adverse endo crine-related effects 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 Ag ency must screen all pesticid e chemicals. Between October 2009 and February 2010, EPA issued test orders/dat a call-ins for th e first group of 67 chemicals, which contains 58 pesticide activ e ingredients and 9 iner t ingredients. A second list of chemicals identified for EDSP screening was published on June 14, 2013 13 and includes some pesticides scheduled for Registration Review and chemicals found in water

. Neither of thes e lists should be construed as a list of known or likely endocrine disruptors.

For further information on the status of the ED SP, the policies and pro cedures, the lists of chemicals, future lists, the test guidelines a nd the Tier 1 screening battery, please visit our website. 14

7. Conclusions

Propoxycarbazone-sodium is a hi ghly mobile, soluble, and persistent compound. The compound is not volatile, but is lik ely to move off of trea ted areas via a combinati on of runoff and leaching. Propoxycarbazone-sodium that reaches aquatic environm ents is likely to re main primarily in the water column, where dilution and degradation act to decrease concentrations over time.

Propoxycarbazone-sodium is practically non-toxic on an acute e xposure basis to all animal taxa, including birds, mammals, terrest rial invertebrates, fish, and aquatic invertebrates. Chronic toxicity effects were observed at high doses in studies of bi rds and mammals. Additional honey bee data are needed to conduct a more complete as sessment of risk to te rrestrial invertebrates (see Section 8 ). Propoxycarbazone-sodium is very highly to xic to vascular aquatic plants but at most moderately toxic to non-vasc ular aquatic plants. Consistent with the herbicidal mode of action, propoxycarbazone-sodium is toxic to terrestrial plan ts, both monocots and dicots.

Terrestrial plants are the only taxa for which risks exceed levels of concern for currently registered propoxycarbazone-sod ium uses on wheat, tritical e, pasture, rangeland, and Conservation Reserve Program land. Direct effects on terrestrial plants could result in indirect effects to all other taxa due to habitat modifications ( e.g. , food sources, shelter, and areas to

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

chemicals.

14 http://www.epa.gov/endo/-Page 45 of 66- reproduce). Spray drift buffers from treated fields are >1,000 ft for li sted terrestrial plants and up to 900 ft for non-listed te rrestrial plants to d ecrease risks below th e levels of concern. Additionally, there is a potential for damage to terrestrial pl ants if surface or groundwater contaminated with propoxycarbazone -sodium is used for irrigation.

8. Data Gaps

Additional data on pollinators is needed to fu lly characterize the risk associated with propoxycarbazone-sodium exposure to all developm ental stages of honey bees, as sensitivity may vary according to life-stage and length of exposure (adult vs. larval and acute vs. chronic, respectively). These data requirements are summar ized in the Guidance for Assessing Pesticide Risks to Bees (USEPA et al. , 2014). The data gaps are summarized in Table 8.1 below, followed by justification tables for the non-guideline studies.

Table 8.1. Propoxycarbazone-sodium Pollinator Toxicity Testing Data Gaps

Test Guideline Study Type Test substance Additional Data Required? Justification

850.3020 (Tier 1) Honey bee adult acute contact toxicity TGAI No Study previously submitted and reviewed is scientifically sound.

850.3030 (Tier 1) Honey bee toxicity of residues on foliage TEP No Data not required because the acute
contact LD 50 > 11 μg a.i./bee.

Non-Guideline Study (Tier 1) 1 Honey bee adult acute oral toxicity TGAI No Study previously submitted and reviewed is scientifically sound.

Non-Guideline Study (Tier 1) 2 Honey bee larvae acute oral toxicity TGAI Yes No data available.

Non-Guideline Study (Tier 1) 3 Honey bee adult chronic oral toxicity TGAI Yes No data available.

Non-Guideline Study (Tier 1) 3 Honey bee larvae chronic oral toxicity TGAI Yes No data available.

Non-Guideline Study (Tier 2) 4 Semi-field testing for pollinators (tunnel or colony feeding studies) TEP Yes 5 No data available.

Non-Guideline Study (Tier 2) Field trial of residues in pollen and nectar TEP Yes 5 No data available.

850.3040 (Tier 2 or 3) Field testing for pollinators TEP Yes 5 No data available.

TGAI = Technical Grade of the Active In gredient; TEP = Typical End-Use Product

1 Honey bee acute oral toxicity test protocol available through OECD TG 213. 15

2 Honey bee acute larval toxicity test protocol available through OECD TG 237. 16 In some cases, information pertaining to acute toxicity to honey bee larvae may be obtained with the chronic honey bee larval test thereby negating the need for separate acute and chronic larval toxicity tests.

3 Draft test protocols are currently being finalized through the OECD.

4 Semi-field tunnel study protocol available through OECD Guidance 75. 17

15 OECD. 1998 a . OECD Guidelines for the Testing of Chemicals. Honeybees, Acute Oral Toxicity Test. 213. http://lysander.sourceoecd.o rg/vl=5988235/cl=12/nw=1/rpsv/cgi- bin/fulltextew.pl?prpsv=/ij/oecdj ournals/1607310x/v1n2/s14/p1.idx
16 OECD. 2013. OECD Guidelines for Testing Chemicals. Honey bee ( Apis mellifera ) larval toxicity test, single exposure. http://www.oecdilibrary.org/environment/test- no-237-honey-bee-apis-mellifer a-larval-toxicity-test-si ngle-exposure _9789264203723-en
17 OECD. 2007. Series on Testing and Assessment Number 75. Guidance document on the honey bee ( Apis mellifera L.) brood test under semifield conditions. Environmental Directorate Joint Meeting of th e Chemicals Committee and the Work ing Party on Chemicals, Pesti cides and Biotechnology. ENV/JM/MONO(2007)22. 31-Aug-2007.-Page 46 of 66- 5 Higher tier studies (Tier 2 and Tier 3) may be required pe nding the results and evaluation of Tier 1 studies. Higher tier studies may be required if the ratio of the EEC and larval or adult bee acute LD 50 >0.4 or the ratio of the EEC and chronic NOAEC >1. Incident data and/or compelling open literature studies can also serve as rationale for requiring Tier 2 and Tier 3 studies. Study protocols should be submitted for review prior to conduct of these studies.

Study Title: Pollinator Acut e Oral Toxicity, Larvae Rationale for Requiring the Data
Terrestrial invertebrates ar e likely to be impacted if exposed to pesticides in various use settings. Pesticide residues may be transferred to pollen and/ or nectar of treated plants and subsequently brought back to the hive where larvae and pupae may be exposed. Theref ore, potential adverse effects to developing bees and other insect pollinators could result from exposure to pesticide residues. Available toxicity studies do not a ddress possible effects on brood (larvae and pupae) survival/development. Because of the potential for pollen and nectar to be contaminated with pesticide residues, and subsequent ly brought back to the hive, it is important to determine the acute oral toxicity of th is compound to bee brood.

The Office of Pesticide Programs has made availa ble a guidance regarding ecological testing for terrestrial invertebrates using th e honeybee as a surrogate test sp ecies. The guidance discusses Tier I laboratory-based acute to xicity studies of individual ho neybee larvae as a critical component of the screening-leve l risk assessment process for examining potential risks from specific routes of exposure. The guidance can be found at: http://www2.epa.gov/pollinatorprotection/pollinator-risk-assessment-guidance . Additional guidance on larval honeybee toxicity test design can be found in OECD Test Guideline 237 http://www.oecdilibrary.org/environment/test-no-237-honey-bee-ap is-mellifera-larval-toxicity-test-singleexposure_9789264203723-en

. Practical Utility of the Data
How will the data be used? The Tier I acute oral toxicity data on honeyb ee larvae serve as a founda tion for the screeninglevel assessment of potential risk to non-target organisms such as federally listed threatened or endangered and non-listed terrestr ial invertebrate insects, incl uding pollinators, and/or modify their designated critical habitat fr om acute oral exposures to pesticid es. The data will be used to reduce uncertainties associated with the risk assessment for terrestrial invertebrates and will improve EPA’s understanding of the potential effect s on terrestrial species and whether there is a differential sensitivity of larval bees relative to adult bees. If acute oral effects data for larvae are not available, risks to terrest rial insects from acute oral exposure will be assumed. How could the data impact the Agency’s future decision-making? The data will inform the determination requi red under FIFRA or the ESA as to whether continued registration of a pest icide is likely to result in un reasonable adverse effects to nontarget species or is likely to adversely affect listed threatened or e ndangered species and/or modify their designated critical habitat. Without these data, EPA may need to presume risk which will limit the flexibility of pesticide products to comply with FIFRA and the ESA, and could result in use restrictions.

http://www.oecd.org/o fficialdocuments/publicdisplaydocument pdf/?cote=env/jm/mono( 2007)22&doclanguage=en-Page 47 of 66- Study Title: Pollinator Ch ronic Oral Toxicity, Adult Rationale for Requiring the Data
Terrestrial invertebrates ar e likely to be impacted if exposed to pesticides in various use settings. Pesticide residues may be transferred to pollen and/ or nectar of treated plants and subsequently brought back to the hive. Therefore, potential chronic effects to a dult honeybees and other pollinators from oral exposure to some pesticid es could exist. Currently available toxicity studies do not address possible lethal and sublet hal effects of chronic oral exposure on adult terrestrial invertebrates and will assist in determin ing whether the sensitivity of adult bees differs from that of earlier life stages. Because of the potential for pollen and nectar to be contaminated with pesticide residues, and subs equently brought back to the hive , it is important to determine the chronic oral toxicity of this comp ound to adult honeybees and other pollinators.

The Office of Pesticide Programs has made availa ble a guidance regarding ecological testing for invertebrates with the honeybee. The guidance discusses Tier I laborat ory-based chronic oral toxicity studies of individual adul t honeybees as a critic al component of the screening-level risk assessment process for examining potential risks from sp ecific routes of exposure. The guidance
can be found at: http://www2.epa.gov/pollinator-protection/ pollinator-risk-assessment-guidance

. Study design elements for the chronic 10-day oral toxicity test with honeyb ees are similar to the OECD Test Guideline 213 acute oral toxicity test http://www.oecd-ilibrary.org/environment/testno-213-honeybees-acute-oral- toxicity-test_9789264070165-en

. Practical Utility of the Data
How will the data be used? The Tier I chronic oral toxicity data on adult bees serve as a foundation for the screening-level assessment of potential risk to non-target organisms including fe derally listed threatened or endangered species and non-listed terrestrial inve rtebrate insects, including pollinators, from chronic oral exposures to pesticides. The data will be used to reduce uncertainties associated with the risk assessment for terrestrial invertebrates and wi ll improve EPA’s understanding of the potential direct and indirect le thal and sublethal effects on a br oad range of terrestrial species, particularly insect pollinators and to determine whether adult toxicity di ffers substantially from other life stages evaluated in othe r Tier I tests. If chronic oral effects data for adults are not available, risks to terrestrial insects from chronic oral exposure will be assumed. How could the data impact the Agency’s future decision-making? The data will inform the determination requi red under FIFRA or the ESA as to whether continued registration of a pest icide is likely to result in un reasonable adverse effects to nontarget species or is likely to adversely affect li sted threatened or endange red species and/or their designated critical habitat. Without these data , EPA may need to presume risk which will limit the flexibility of pesticide products to comply with FIFRA and the ESA, and could result in use restrictions.

Study Title: Pollinator Chro nic Oral Toxicity, Larvae Rationale for Requiring the Data
Terrestrial invertebrates ar e likely to be impacted if exposed to pesticides in various use settings. Pesticide residues may be transferred to pollen and/ or nectar of treated plants and subsequently-Page 48 of 66- brought back to the hive where larvae and pupae ma y be exposed. Therefor e, potential effects to developing bees could result from ch ronic oral exposure to pesticide residues. Available toxicity studies do not address possible chronic effects on brood (larvae and pupae) survival. Because of the potential for pollen and nectar to be contaminated with pestic ide residues, and subsequently brought back to the hive, it is important to dete rmine chronic larv al/pupal toxicity and whether adult emergence is adversely affected. This study will provide information on whether honeybee larvae differ in sensitivity from adul t bees following chronic exposure.

The Office of Pesticide Programs has made availa ble a guidance regarding ecological testing for invertebrates with the honeybee. The guidance discusses Tier 1 laboratory-based chronic oral toxicity studies of individual hone ybee larvae as a critic al component of the screening-level risk assessment process for examining potential risks from sp ecific routes of exposure. The guidance
can be found at: http://www2.epa.gov/pollinator-protection/ pollinator-risk-assessment-guidance

. Additional information on larval honeybee toxicity repeat exposur e test design can be found in the OECD draft guidance http://www.oecd.org/env/ehs/testing/Draf t_GD_honeybees_rep_exp_for_2nd_CR_25_Novembe r_2013.pdf

. Practical Utility of the Data
How will the data be used? The Tier I chronic oral toxicity data on bee larvae serve as a foundation for the screening-level assessment of potential risk to non-target organisms including fe derally listed threatened or endangered and non-listed terrestria l invertebrate insects, includi ng pollinators, from chronic oral exposures to pesticides. The data will be used to reduce uncertain ties associated with the risk assessment for terrestrial invertebrates and will improve EPA’s understa nding of the potential direct and indirect lethal and s ublethal effects on a broad range of terrestrial species, particularly insect pollinators. These data wi ll also assist in determining wh ether early life st ages of the bee differ in their sensitivity to pesticides relative to adults. If ch ronic oral effects data for larvae are not available, risks to terrest rial insects from chronic or al exposure will be assumed. How could the data impact the Agency’s future decision-making? The data will inform the determination requi red under FIFRA or the ESA as to whether continued registration of a pest icide is likely to result in un reasonable adverse effects to nontarget species or is likely to adversely affect listed threatened or e ndangered species and/or modify their designated critical habitat. Without these data, EPA may need to presume risk which will limit the flexibility of pesticide products to comply with FIFRA and the ESA, and could result in use restrictions.

Study Title: Pollinator Tier II Semi-Field Toxicity Testing (tunnel/enclosure studies) Rationale for Requiring the Data
Tier II studies are conditional on the outcome of the screening- level assessment where acute and/or chronic risk levels of concern have been exceeded for terrestrial invertebrates. Terrestrial invertebrates are likely to be imp acted if exposed to pesticides in various use settings. Pesticide residues may be transferred to pollen and/or nect ar of treated plants and subsequently brought back to the hive and may adve rsely affect developing brood (e gg, larvae, and pupae) and adult bees. Screening-level (Tier I) studies of individual bees do not address possible effects and/or-Page 49 of 66- exposure to pesticide residues at th e colony-level. Because of the potential for pollen and nectar to be contaminated with pesticide residues, an d subsequently brought back to the hive, it is important to determine whether bee colonies may be negative ly affected under relatively controlled exposure conditions of a semi-field st udy. In addition to providing effects data, these studies can provide data on expos ure as pesticide residues in po llen/nectar of treated plants.

The Office of Pesticide Programs has made availa ble a guidance regarding ecological testing for invertebrates with the honeybee. The guidance describes the tiered testing process and can be
found at: http://www2.epa.gov/pollinator-protection/po llinator-risk-assessment-guidance

. Additional information on honeybee colony studie s under semi-field conditions can be found in
the OECD Guidance 75 http://www.oecd.org/officialdocuments/publ icdisplaydocumentpdf/?cote=env/jm/mono%28

. Practical Utility of the Data
How will the data be used? Tier II colony-level data will be used to asse ss potential risk to non-target organisms including listed and non-listed terrestrial social invertebrate species a nd to determine whether effects observed in the screening-level (Tier I) laboratory-b ased studies of individual bees are evident in colony-level studies under semi-field conditions. The Tier II semi-fie ld test of whole colonies is a relatively controlled study, i.e ., bees are confined to a specific area, that is designed to represent potential field- level exposure and account for hive dynamics, which are not achievable from other pollinator studies. This study will be used to determine whet her adverse effects to insect pollinators at the whole colony level, may result for the use of pesticides and will help to refine risk estimates derived in the screening- level risk assessment for beneficial terrestrial invertebrates. Measured residue s in pollen/nectar can also be used to refine risk estimates derived from model-based or default values in the screening-level assessment.

How could the data impact the Agency’s future decision-making? The data will inform the determination requi red under FIFRA or the ESA as to whether continued registration of a pest icide is likely to result in un reasonable adverse effects to nontarget species or is likely to adversely affect fe derally listed threatened or endangered species or their designated critical habitat. Without thes e data, EPA may need to presume risk which will limit the flexibility of pesticide products to comp ly with FIFRA and the ESA, and could result in significant use restrictions.

Study Title: Pollinator Tier II Semi-Fie ld Toxicity Testing (feeding studies) Rationale for Requiring the Data Pesticide residues may be transferred to pollen and/ or nectar of treated plants and subsequently brought back to the hive, and may adversely af fect developing brood (egg, larvae, and pupae) and adult bees. Tier II feeding studies are conditiona l on the outcome of the screening-level assessment where acute and/or chronic risk levels of concern have been exceeded for terrestrial invertebrates based on Tier I st udies of individual bees. Feedi ng studies utilize free foraging bee colonies that are “dosed” with specific quanti ties of test material a nd represent a means of ensuring exposure to the test ma terial through spiked pollen and/or sugar solutions fed to the colony while still allowing the bees to forage freely. Since bee colonies are not confined to-Page 50 of 66- enclosures, colonies can be e xposed for longer duration periods without subjecting the bees to stress that typically results from Tier II tunnel studies. Availabl e toxicity studies of individual bees (Tier 1) conducted to support screening-le vel assessments do not address possible effects and/or exposure to pesticide residues at the colo ny-level. Because of the potential for pollen and nectar to be contaminated with pesticide residues, and subsequently brought back to the hive, it is important to determine whethe r bee colonies may be negatively affected where bees are free foraging and have the option to collect/consume alternative forage items beyond the spiked food.Since multiple dose levels can be more readily tested, feeding studies can help to define doseresponse relationships at the whole colony level.

The Office of Pesticide Programs has made availa ble a guidance regarding ecological testing for invertebrates with the honeybee. The guidance describes the tiered testing process and can be
found at: http://www2.epa.gov/pollinator-protection/po llinator-risk-assessment-guidance

. Additional information on honeybee colony feeding studies can be found in the EPPO Guidance
170 at: http://www.nationalbeeunit.com/index.cfm?pageId=187

. Practical Utility of the Data
How will the data be used? Tier II colony feeding data will be used to a ssess potential risk to non-ta rget organisms including listed and non-listed terrestrial so cial invertebrate species. Th e colony feeding study is designed to represent potential field-le vel exposure and account for hi ve dynamics using longer duration exposure periods than are possible in Tier II tunnel studies. The study will be used to determine whether potential adverse effects to insect pollinators at the whole colony level when bees are able to forage naturally beyond the spiked food. Results from the feed ing study will help to refine the screening-level risk assessment for bene ficial terrestrial invertebrates that were based on Tier I studies on individual bees. Since feed ing studies can help to define a dose-response relationship at the colony level, the studies can provide a means of determining exposure thresholds below which the likelihood of adverse effects on colonies may be low.

How could the data impact the Agency’s future decision-making? Tier II colony-level data will be used to refine screening-level risk estimates derived using Tier I laboratory-based data on individu al bees. The Tier II data will inform the determination required under FIFRA or the ESA as to whether continued re gistration of a pesticide is likely to result in unreasonable adverse effects to non-ta rget species or is likely to a dversely affect federally listed threatened or endangered species or their designated critical ha bitat. Without these data, EPA may need to presume risk which will limit the flexibility of pesticide products to comply with FIFRA and the ESA, and could result in significant use restrictions.

Study Title: Residues in Pollen and Nectar Rationale for Requiring the Data
Terrestrial invertebrates are likely to be impacted if exposed to pesticide residues in various use settings. Pesticide residues may be transferred to pollen and/or nectar of treated plants and subsequently brought back to hive where all life stages may be exposed. For some pesticides, the quantification of pollinator-relevant residues in treated flowering plants is needed, since pollinators will be exposed to residues from either cu rrent or prior season applications (due to the potential for residues to accumulate in plants and trees). Residues in edib le/transportable-to-hive-Page 51 of 66- parts of treated trees and plants, including (w here appropriate), but not limited to, guttation water, sap/resins, whole plant tissue ( e.g., leaves, stems), as well as blooming, pollen-shedding, and nectar producing parts ( i.e. , flowers and, if present, extra-fl oral nectaries) of plants may inform the potential for risk. Studies should be designed to provide residue data for crops and application methods of concern.

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

. Practical Utility of the Data
How will the data be used? Measured residue data will be used to refine conservative estimates of pesticide exposure and reduce uncertainties associated with the Ti er I exposure assessment by providing direct measurements of pesticide concentrations result ing from actual use settin gs. Measured residues may provide a more realistic under standing of exposure through c ontact or ingestion with which to calculate risk quotients for individual bees as well as to characterize ex posure to the colony. If measured residue data are not available, risk estimates for terrestrial insects will be based on model-generated or default values used to support the screen ing-level assessment.

How could the data impact the Agency’s future decision-making? The data will inform the determination requi red under FIFRA or the ESA as to whether continued registration of a pest icide is likely to result in un reasonable adverse effects to nontarget species or is likely to adversely affect fe derally listed threatened or endangered species or their designated critical habita t. Without these data, EPA will have to rely on conservative estimates of exposure which will limit the flexibil ity of pesticide products to comply with FIFRA and the ESA, and could resu lt in use restrictions.

9. References

Fletcher, J.S., J.E. Nellessen, and T.G. Pfleeger. 1994. Literature review and evaluation of the EPA food-chain (Kenaga) nomogram, and instrument for estimating pesticide residues on plants. Environmental Toxicology and Chemistry 13 (9):1383-1391.

Hoerger, F., and E.E. Kenaga. 1972. Pesticide resi dues on plants: Correlation of representative data as a basis for estimation of their magnitude in the envi ronment. In F. Coulston and F. Korte, eds., Environmental Quality and Safety: Chemistry, T oxicology, and Technology, Georg Thieme Publ, Stuttgart, West Germany, pp. 9-28.

USEPA. 2014a. BEAD Chemical Profile (BCP) for Regist ration Review: Propoxycarbazone sodium (122019). U.S. Environmental Protection Agency, Office of Pesticide Programs, Biological and Economic Analysis Division, October 22, 2014.

USEPA. 2014b. Propoxycarbazone-s odium (122019) Label Use Report Package in Support of Registration Review. U.S. Environmental Prot ection Agency, Office of Pesticide Programs, Biological and Economic Analysis Division, September 10, 2014.-Page 52 of 66- USEPA. 2014c. Propoxycarbazone-s odium: Drinking Water Exposure Assessment for Registration Review. U.S. Environmental Protection Agency, Office of Pesticide Programs, Environmental Fate and Effects Division. December 4, 2014. DP Barcode: 423552.

USEPA, PMRA, and CDPR. 2014. Guidance for Assessing Pesticide Risks to Bees. Office of Pesticide Programs, USEPA, Washington D.C. Health Cana da Pest Management Regulatory Agency, Ottawa, ON, Canada. California De partment of Pesticide Regulati on, Sacramento, CA. June 23,
2014.

USEPA. 2013. Guidance on Modeling Offsite Deposition of Pesticides via Spray Drift for Ecological and Drinking Water Assessments. U.S. Environmental Protection Agency, Office of Chemical Safety and Pollution Prevention, Office of Pestic ide Programs, Environmental Fate and Effects Division, December 20, 2013.

USEPA. 2009a. ECOTOXicology Database, v. 4.0. Acce ssed on 14 November 2014. Available online at http://cfpub.epa.gov/ecotox/.

USEPA. 2009b. Ecological Incident Information Sy stem, v. 2.1. Accessed on 20 November 2014. Description online at http://www.epa.gov/pesticides/science/models_db.htm

.

USEPA. 2009c. Guidance for Selecting Input Paramete rs in Modeling the Environmental Fate and Transport of Pesticides, Version 2.1. U.S. Environmental Protection Agency, Office of Prevention, Pesticides and Toxic Substances, Offi ce of Pesticide Programs, Environmental Fate and Effects Division, October 22, 2009. Online at: http://www.epa.gov/oppefed1/models/water/input_parameter_guidance.htm

USEPA. 2008. Ecological Risk Assessment Addressing the Proposed Registration of Propoxycarbazonesodium for New Use on Rangeland. U.S. Environm ental Protection Agency, Office of Pesticide Programs, Environmental Fate and Effects Divi sion. December 17, 2008. DP Barcode: 348511.

USEPA. 2006. TERRPLANT v. 1.2.2 User’s Guide. O ffice of Pesticide Programs, Environmental Fate and Effects Division, Washington, D.C. December 26, 2006.

USEPA. 2004a. Overview of the Ecological Risk Assessment Process in the Office of Pesticide Programs, U.S. Environmental Protection Agency. Endangered and Threatened Species Effects Determinations. Office of Prevention, Pesticid es and Toxic Substances, Office of Pesticide Programs, Washington, D.C., January 23, 2004. Available online at http://www.epa.gov/oppfead1/endanger/c onsultation/ecorisk-overview.pdf

.

USEPA. 2004b. Section 3 Registration Request fo r Proposed Use of Propoxycarbazone-sodium on Wheat. U.S. Environmental Protection Agency, Office of Pesticide Programs, Environmental Fate and Effects Division. March 15, 2004. DP Barcodes: D284671, D284675, D284677, D284680, D274582, D274584, D274586, D274588, D294147.

USEPA. 1998. Guidelines for Ecological Risk Ass essment. EPA/630/R-95/002F. Published in 63 FR 26846; May 14, 1998. U.S. Environmental Protection Agency, Washington, DC. April, 1998.-Page 53 of 66- 9.1. Submitted Product Chemistry a nd Environmental Fate Studies

MRID Citation 45012634 Fent, G.; Kelly, I. (1997) Adsorption/Desorption of MKH 6561 in Five Soil Types: Lab Project Number: M1182101: BAC 01: 107731. Unpublished study prepared by Staatliche Lehr-und Forschungsanstalt fur Landwirtschaft, Weinbau und Gartenbau (SLFA). 71 p.
45012635 Fent, G.; Kelly, I. (1997) Adsorption/Desorption of MKH 6561 Carboxylic Acid (MKH 7018), a Degradate of MKH 5461 in Five Soil Types: Lab Project Number: M1182102: BAC02: 107732. Unpublished study prepared by Staatliche Lehr-und Forschungsanstalt fuer Landwirtschaft, Weinbau und Gartenbau (SLFA). 58 p.

45012636 Fent, G.; Kelly, I. (1997) Adsorption/Desorption of MKH 6561 Sulfonamide Acid (MKH 7283), a Degradate of MKH 6561, in Five Soil Types: Lab Project Number: M1182105: BAC04: 107735. Unpublished study prepared by Staatliche Lehr-und Forschungsanstalt fur Landwirtschaft, Weinbau und Gartenbau (SLFA). 31 p.

45012637 Fent, G.; Kelly, I. (1997) Adsorption/Desorption of MKH 6561 Sulfonamide Methyl Ester(STJ 4934), a Degradate of MKH 6561, in Five Soil Types: Lab Project Number: M1182104: BAC06: 107734. Unpublished study prepared by Staatliche Lehr-und Forschungsanstalt fur Landwirtschaft, Weinbau und Gartenbau (SLFA). 26 p.

45012638 Fent, G.; Kelly, I. (1997) Adsorption/Desorption of Saccharin (MKH 7284), a Degradate of MKH 6561, in Five Soil Types: Lab Project Number: M1182103: BAC03: 107733. Unpublished study prepared by Staatliche Lehr-und Forschungsanstalt fur Landwirt schaft, Weinbau und Gartenbau (SLFA). 57 p.
45012701 Mattern, G.; Li, Y.; Wiedmann, J. (1999) Analytical Method for the Determination of MKH 6561 and Seven Degradates Soil: Lab Project Number: M2022103: M2022104: 108826. Unpublished study prepared by Bayer Corp. and Ricerca, Inc. 57 p.
45012702 Brumhard, B.; Knoell, H.; Bornatsch, W. (1999) Photolysis of (phenyl-UL-(carbon-14)) MKH 6561 in Aqueous Solutions: Lab Project Number: M1120786-5: 109107. Unpublished study prepared by Bayer AG. 70 p.
45012703 Brumhard, B.; Knoell, H.; Bornatsch, W. (1999) Photolysis of (Triazolinone-3-(carbon-14)) MKH 6561 in Aqueous Solutions: Lab Project Number: 109108: M1120787-6. Unpublished study prepared by Bayer AG. 64 p.
45012704 Riegner, K. (1998) Aerobic Aquatic Degradation and Metabolism of MKH 6561 in Water-Sediment System: Lab Project Number: M1510785-7: 109112. Unpublished study prepared by Bayer AG. 83 p. 45012705 Hellpointer, E. (1998) Determination of the Volatisation Behaviour of MKH 6561 (WG 70) in a Field Trial: Lab Project Number: 109113: M1180924-5. Unpublished study prepared by Bayer AG. 41 p. 45012706 Blumhorst, M.; Bloomberg, A. (1999) Aerobic Degradation of N-Methyl Propoxy Triazolinone Amide (A Metabolite of MKH 6561) in Three Soils: Lab Project Number: M1042109: 122S28: 108703. Unpublished study prepared by EPL-Bio- Analytical Services, Inc. 77 p.
45012707 Arthur, E.; O'Brien, B.; Parker, G. et al. (1999) Anaerobic Aquatic Metabolism of (Phenyl-U-(carbon14)) MKH 6561 in a Washington Water and Sediment Test System: Lab Project Number: M1042401: 108916. Unpublished study prepared by Bayer Corp. 72 p.
45012708 Arthur, E.; O'Brien, B.; Parker, G. et al. (1999) Anaerobic Aquatic Metabolism of (Triazolinone-3- (carbon-14))MKH 6561 in a Washington Water and Sediment Test System: Lab Project Number: 108917: M1042402. Unpublished study prepared by Bayer Corp. 72 p.
45012709 Hein, W.; Wujcik, C. (1999) Adsorption/Desorption of (Phenyl-U-(carbon-14))4-Hydroxy Saccharin, a Degradate of MKH 6561 in Five Soil Types: Lab Project Number: M1182107: BAC16: 108700. Unpublished study prepared by SLFA. 79 p.
45012710 Bruns, G.; Hoshowski, J. (1999) Independent Laboratory Validation of the Analytical Method for the Determination of MKH 6561 and Seven Degradates in Soil: Lab Project Number: M1112101: 109124: 108826-1. Unpublished study prepared by Enviro-Test Labs. 102 p.-Page 54 of 66- 45012711 Blumhorst, M.; Bloomberg, A. (1999) Aero bic Degradation N-Methyl Propoxy Trizolinone (a Metabolite of MKH 6561) in Quincy Loamy Sa nd from Ephrata, WA: Lab Project Number: M1042111: 122S30: 108705. Unpublished study prepared by EPL Bio-Analytical Services, Inc. 47 p.
45012712 Blumhorst, M.; Bloo mberg, A. (1999) Aerobic Degradation S accharin (a Metabolite of MKH 6561) in Quincy Loamy Sand from Ephrata, WA: Lab Project Number: M1042110: 122S29: 108704. Unpublished study prepared by EPL Bio- Analytical Services, Inc. 47 p.
45012713 Hein, W.; Wujcik, C. (1999) Adsorption/Desorption of N-Methyl Propoxy Triazolinone Amide a Degradate of MKH 6561, in Five Soil Types: Lab Project Number: M1182108: BAC15: 108701. Unpublished study prepared by SLFA. 82 p.
45012714 Blumhorst, M.; Bloo mberg, A. (1999) Aerobic Degradation of 4-Hydroxy Saccharin (a Metabolite of MKH 6561) in Three Soils: Lab Project Number: 108702: 122S27: M1042108. Unpublished study prepared by EPL-Bio-Analyti cal Services, Inc. 71 p.
45012715 Wood, S. (1999) Terrestrial Field Dissipation of MKH 6561 in Washington Soil, 1996: Lab Project Number: 108734: M1022103: 98-B-263. Unpublished study prepared by Qualls Agricultural Labs. and Ricerca, Inc. 296 p.
45012716 Wood, S.; Koch, D. (1999) Terrestrial Field Dissipation of MKH 6561 in Kansas Soil, 1996: Lab Project Number: 108736: 98-B-265: M1022104. Unpublished study prepared by Qualls Agricultural Labs. and Ricerca, Inc. 321 p.
45012717 Malekani, K., and R. Ripperger. 1999. Freezer stability of 4-hydro xy saccharin and N-methyl propoxy triazolinone amide (MKH 6561 Metabolites) in Quin cy loamy sand. Unpublished study performed by Bayer Corporation, Stilwell, KS
45012718 Smith, D.M., D.L. Green, and C.E. Wujcik. 1999. Freezer stability of [phe nyl-u-14C]MKH 6561 and five metabolites in Quincy loamy sand. Unpublished study performed by Bayer Corporation, Stilwell, KS; and submitted by Bayer Corporation, Kansas City, MO. Bayer Study No. M 1 132 10 1, Bayer Report No. 108846. Experimental start date November 2 1, 1996, and completion date February 8, 1999 (p. 13). Final report issued July 2 1, 1999.

45012718 Smith, D.M., D.L. Green, and C.E. Wujcik. 1999. Freezer stability of [phe nyl-U-14C]MKH 6561 and five metabolites in Quincy loamy sand. Unpublished study performed by Bayer Corporation, Stilwell, KS; and submitted by Bayer Corporation, Kansas City, MO.
45012719 Koch, D.; Wood, S. (1999) Terrestrial Field Dissipation of MKH 6561 in Utah Soil, 1997: Lab Project Number: 108735: 98-B-264: M1022102. Unpublished study prepared by Bayer Corp. and ABC Labs. 282 p.
45012720 Helfrich, K.; Bloomberg, A.; Ripperger, R. (1999) Aerobic Metabolism of (Phenyl-U-(carbon 14))MKH 6561 in Quincy Loamy Sand from Ephrata Washington: Lab Project Number: 107650: M1042101. Unpublished study prepared by Bayer Corp. 59 p.
45012721 Henry, T.; Bloomberg, A.; Ripperger, R. (1999) Aerobic Metabolism of (Triazolinone-3-(carbon 14))MKH 6561 in Three German Soils: Lab Project Number: M1042107: 108727. Unpublished study prepared by Bayer Corp. 76 p.
45012722 Helfrich, K.; Bloomberg, A.; Ripperger, R. et al. (1999) Aerobic Metabolism of (Phenyl-U-(carbon 14))MKH 6561 in Three German Soils: Lab Project Number: 107652: M1042106. Unpublished study prepared by Bayer Corp. 92 p.
45012723 Helfrich, K.; Bloomberg, A.; Ripperger, R. et al. (1999) Aerobic Metabolism of (Triazolinone-3- (carbon 14))MKH 6561 in Quincy Loamy Sand from Ephrata, Washington: Lab Project Number: 107651: M1042103. Unpublished study prepared by Bayer Corp. 63 p.
45012724 Knoell, H.; Brumhard, B. (1999) Hydrolysis of (Triazolinone-3-(carbon 14))MKH 6561 in Sterile Aqueous Solutions: Lab Project Number: 109222: M1110777-4. Unpublished study prepared by Bayer AG. 56 p. 45012725 Knoell, H.; Brumhard, B. (1999) Hydrolysis of (Triazolinone-3-(carbon 14))MKH 6561 in Sterile Aqueous Solutions: Lab Project Number: 10922-1: M111077-4. Unpublished study prepared by Bayer AG. 15 p.-Page 55 of 66- 45012726 Shadrick, B.; Ripperger, R.; Bloomberg, A. (1999) The Leaching Potential of (Phenyl-U-(carbon 14))MKH 6561 in Sulfonamide Methyl Ester (STJ 49 34) in Quincy Loamy Sand: Lab Project Number: 108718: M1092102. Unpublished study prepared by Bayer Corp. 42 p.
45012727 Henry, T.; Ripperger, R.; Bloomberg, A. et al . (1999) Leaching Potential of Aged MKH 6561 Residues in Quincy Loamy Sand: Lab Project Number: 108841: M1092101. Unpublished study prepared by Bayer Corp. 80 p.
45012728 Brumhard, B.; Knoell, H. (1999) Photolysis of (Triazolinone-3-(carbon 14))MKH 6561 on Soil Surfaces: Lab Project Number : M1130798-9: 1 09244. Unpublished st udy prepared by Ba yer AG. 58 p. 45012729 Brumhard, B.; Knoell, H. (1 999) Photolysis of (Phenyl-UL-(car bon 14))MKH 6561 on Soil Surfaces: Lab Project Number: 109243: M1130780-0. Unpublished study prepared by Bayer AG. 57 p. 45012730 Brumhard, B.; Knoell, H. (1999) Photolysis of (Phenyl-UL-(carbon 14))MKH 7284 in Aqueous Solutions: Lab Project Number: 109245: M1120834-9. Unpublished study prepared by Bayer AG. 52 p. 45012731 Fent, G.; Kelley, I. (1997) Adsorption/Desorption of N-Methyl Propoxy Triazolinone (MKH 7017), a Degradate of MKH 6561, in Five Soil Types: Lab Project Number: BAC05: 107736. Unpublished study prepared by SLFA. 57 p.
45012732 Brumhard, B. (1998) Method for the Determination of MKH 6561 in Drinking Water by HPLC Using Injection as Well as On-Line Solid Phase Extr action: Lab Project Number: MR-741/98: 109114. Unpublished study prepared by Bayer AG. 22 p.
45012733 Brumhard, B.; Knoell, H. (1999) Hydrolysis of (Phenyl-(carbon 14))MKH 6561 in Sterile Aqueous Buffer Solutions: Lab Project Number: M1110776-3: 109127. Unpublished study prepared by Bayer AG. 68 p.45012734 Hellpointer, E. (1997) Determination of the Quantum Yield and Assessment of the Environmental HalfLife of the Direct Photodegradation of MKH 6561 in Water: Lab Project Number: M1430772-4: 109450. Unpublished study prepared by Bayer AG. 32 p.
45012735 Schafer, H. (1999) Calculation of DT-50 Va lues of MKH 6561 Metabolite MKH 7017 in Soil Under Aerobic Conditions: Lab Project Number: P66896546: 109396. Unpublished study prepared by Bayer AG. 17 p.
45012736 Schafer, H. (1999) Calculation of DT-50 Valu es of MKH 6561 Metabolite MKH 7284 and STJ 4934 in Soil Under Aerobic Conditions: Lab Project Number: 109397: P66896546. Unpublished study prepared by Bayer AG. 23 p.
45012737 Fritz, R. and K. Spiegel. 1999. Lysimeter study on the degradation and translocation of the herbicide MKH 6561 under field conditions. Unpublished study performed by Bayer AG, Crop Protection Business Group, Crop Protection-Development, Germany.
45012738 Schramel, 0 . 1999. Dissipation of MKH 6561 (70 WG) in soil under field conditions (France, Germany, Great Britain). Unpublished study performed by Bayer AG, Crop Business Group, Crop Protection-Development, Leverkusen, Germany,
45012739 Schramel, 0. 1999. Amendment to report: Dissipation of MKH 6561 (70 WG) in soil under field conditions (France, Germany, Great Britain). U npublished study performed by Bayer AG, Crop Protection Business Group, Crop Protection Development, Schramel, 0 . 1999. Dissipation of MKH 6561 (70 WG) in soil under field conditions (France, Germany, Great Britain). Unpublished study performed by Bayer AG, Crop Business Group, Crop Protection-Development, Leverkusen, Germany,

45012740 Schafer, H. (1999) Calcula tion of DT-50 of MKH 6561 Metabolite STJ 4934 Generated by Hydrolysis in Sterile Aqueous Buffer Solutions: Lab Project Number: 109398: P68896511. Unpublished study prepared by Bayer AG. 14 p.
46874601 Gould, T. (2006) Freezer Storage Stability of MKH 6561 and Pr -2-OH MKH 6561 in Turnip Tops, Turnip Tops, Turnip Roots, and Mustard Greens. Project Number: RAMIY001, M1131601. Unpublished study prepared by Bayer Corp. 62 p.-Page 56 of 66- 9.2. Submitted Ecotoxicity Studies

MRID Citation
45012505 Pauluhn, J. (1995) MKH 6561 Study on Acute Inhalation Toxicity in Rats According to OECD No. 403: Lab Project Number: 23897: T4055671: 107402. Unpublished study prepared by Bayer AG. 53 p. 45012509 Krotlinger, F. (1994) MKH 6561 Study for Acute Oral Toxicity in Rats: Lab Project Number: 23480: T8055657: 107412. Unpublished study prepared by Bayer AG. 29 p. 45012529 Eiben, R. (1999) MKH 6561 (c.n.: Procarbazone-Sodium) Two-Generation Study in Wistar Rats: Lab Project Number: 109096: 28792: T1061527. Unpublished study prepared by Bayer AG. 997 p. {OPPTS 870.3800}
45012801 Drottar, K.; Krueger, H. (1998) MKH 6561 Technical: A Flow-Through Life-Cycle Toxicity Test with the Saltwater Mysid (Mysidopsis bahia): Lab Project Number: 149A-112: 108108. Unpublished study prepared by Wildlife International Ltd. 55 p.
45012802 Bowers, L.; Lam, C. (1999) Chronic Toxicity of MKH 6561 Technical to the Waterflea (Daphnia magna) Under Static Renewal Conditions: Lab Project Number: M1840702: 108845. Unpublished study prepared by Bayer Corporation. 51 p.
45012803 Bowers, L. (1999) Toxicity of MKH 6561 Technical to the Blue-Green Alga Anabaena flos-aquae: Lab Project Number: M1883801: 107718. Unpublished study prepared by Bayer Corporation. 30 p. 45012804 Palmer, S.; Krueger, H. (1998) MKH 6561 Technical: A 96 Hour Flow-Through Acute Toxicity Test with the Saltwater Mysid (Mysidopsis bahia): Lab Project Number: 149A-110: 108112. Unpublished study prepared by Wildlife International, Ltd. 44 p.
45012805 Palmer, S.; Krueger, H. (1998) MKH 6561 Technical: A 96 Hour Shell Deposition Test with the Eastern Oyster (Crassostrea virginica): Lab Project Number: 149A-111: 108121. Unpublished study prepared by Wildlife International, Ltd. 44 p.
45012806 Hall, A. (1997) Acute Toxicity of MKH 6561 Technical to the Bluegill (Lepomis microchirus) Under Static-Renewal Conditions: Lab Project Number: M1 810301: 107748. Unpublished study prepared by Bayer Corporation. 29 p.
45012807 Bowers, L.; Lam, C. (1998) Toxicity of MKH 6561 Technical to the Freshwater Diatom Navicula pelliculosa: Lab Project Number: M1883401: 108487. Unpublished study prepared by Bayer Corporation. 32 p.
45012808 Bowers, L. (1998) Acute Toxicity of MKH 6561 Technical to the Waterflea (Daphnia magna) under Static Conditions: Lab Project Number: M1820701: 107841. Unpublished study prepared by Bayer Corporation. 28 p.
45012809 Hall, A. (1998) Acute Toxicity of MKH 6561 Technical to the Rainbow Trout (Oncorhynchus mykiss) Under Static Conditions: Lab Project Number: M18 12201: 108066. Unpublished study prepared by Bayer Corporation. 29 p.
45012810 Hall, A. (1998) Acute Toxicity of MKH 6561 Technical to the Sheepshead Minnow (Cyprinodon variegatus) Under Static Conditions: Lab Project Number: M1832801: 108065. Unpublished study prepared by Bayer Corporation. 30 p.
45012811 Bowers, L.; Lam, C. (1998) Chronic Toxicity of MKH 6561 Technical to the Waterflea (Daphnia magna) Under Static Renewal Conditions: Lab Project Number: M1840701: 108140. Unpublished study prepared by Bayer Corporation. 46 p.
45012812 Bowers, L.; Lam, C. (1999) Toxicity of MKH 6561 Technical to the Marine Diatom Skeletonema costatum: Lab Project Number: M1883601: 108493. Unpublished study prepared by Bayer Corporation. 32 p. 45012813 Hancock, G. (1999) MKH 6561 Technical: An Acute Oral LD50 with Northern Bobwhite: Lab Project Number: M1711701: 108741. Unpublished study prepared by Bayer Corporation. 33 p.-Page 57 of 66- 45012814 Bowers, L.; Lam, C. (1999) Toxicity of MKH 6561 Technical to the Green Alga Selenastrum capricornutum: Lab Project Number: M1883501: 108820. Unpublished study prepared by Bayer Corporation. 33 p. 45012815 Bowers, L.; Lam, C. (1999) Toxicity of MKH 6561 Technical to Lemna gibba G3: Lab Project Number: M1883701: 108338. Unpublished study prepared by Bayer Corporation. 35 p. 45012816 Hancock, G. (1999) Technical MKH 6561: A Subacute Dietary LC50 with Northern Bobwhite: Lab Project Number: M1721701: 108802. Unpublished study prepared by Bayer Corporation. 48 p. 45012817 Hall, A.; Lam, C. (1999) Early Life Stage Toxi city of MKH 6561 to the Fathead Minnow (Pimephales promelas): Lab Project Number: M1851201: 108453. Unpublished study prepared by Bayer Corporation. 55 p.
45012818 Schmitzer, S. (1998) Laboratory Testing for Toxicity (Acute Contact and Oral LD50) of MKH 6561 on Honey Bees (Apis mellifera L.) (Hymenoptera, Apidae): Lab Project Number: 4150036: 109135. Unpublished study prepared by Institute for Biologi cal Analysis and Consulting IBACON GmbH. 30 p.
45012821 Hancock, G.; Webster, C. (1999) Technical MKH 6561: A Subacute Dietary LC50 with Mallards: Lab Project Number: M1720801: 109144. Unpublished study prepared by Bayer Corporation. 48 p. 45012822 Dorgerloh, M. (1999) MKH 8394 (A Metabolite of MKH 6561)-Toxicity (7 Days) to Lemna gibba G3: Lab Project Number: E 412 1440-6: 109223: DOM 98094. Unpublished study prepared by Bayer AG. 40 p. 45012823 Hancock, G.; Hansen, C.; Hall, A. (1999) Tier 2 Seedling Emergence and Vegetative Vigor Nontarget Phytotoxicity Study Using MKH 6561 70WG Formulation: Lab Project Number: M1201601: 108843. Unpublished study prepared by Bayer Corporation. 110 p.
45012825 Heimbach, F. (1998) Acute Toxicity of MKH 6561 (tech) to Earthworms (E isenia fetida): Lab Project Number: E 310 1400-9: 109369. Unpublished study prepared by Bayer AG. 18 p. 45012826 Heimbach, F. (1998) Acute Toxicity of MKH 7017 (A Metabolite of MKH 6561) to Water Fleas (Daphnia magna): Lab Project Number: 109367: E 320 1426-8. Unpublished study prepared by Bayer AG. 26 p.
45012827 Dorgerloh, M. (1998) MKH 7017 (A Metabolite of MKH 6561)-Acute Toxicity (96 Hours) to Bluegill (Lepomis macrochirus) in a Static Test: Lab Project Number: 109363: E 252 1419-4: DOM 98052. Unpublished study prepared by Bayer AG. 44 p.
45012828 Dorgerloh, M. (1998) MKH 8394 (Free Ac id of MKH 7018, a Metabolite of MKH 6561)-Acute Toxicity (96 Hours) to Bluegill (Lepomis macrochi rus) in a Static Test: Lab Project Number: E 252 1418-3: 109364: DOM 98054. Unpublished study prepared by Bayer AG. 44 p.
45012829 Heimbach, F. (1998) Acute Toxicity of MKH 8394 (Free Acid of MKH 7018, a Metabolite of MKH 6561) to Water Fleas (Daphnia magna): Lab Project Number: 109368: E 320 1427-9: HBF/DM 199. Unpublished study prepared by Bayer AG. 26 p. 45012830 Dorgerloh, M. (1998) MKH 7017 (a Metabolite of MKH 6561) Toxicity (7 Days) to Lemna gibba G3: Lab Project Number: E 412 1441-7: 109366: DOM 98114. Unpublished study prepared by Bayer AG. 31 p. 45012831 Dorgerloh, M. (1998) MKH 6561 WG 70-Influence on the Growth of the Green Alga, Selenastrum capricornutum: Lab Project Number: E 323 1396-7: 109360. Unpublished study prepared by Bayer AG. 38 p. 45012832 Gallagher, S.; Martin, K.; Beavers, J. et al. (1999) MKH 6561 Technical: A Reproduction Study with the Mallard (Anas platyrhynchos): Lab Project Number: 149-180: 109381. Unpublished study prepared by Bayer AG. 156 p.
45012833 Dorgerloh, M. (1998) MKH 7017 (a Metabolite of MKH 6561)-Influence on the Growth of the Green Alga, Selenastrum capricornutum: Lab Project Number: E 323 1393-4: 109361: DOM 98049. Unpublished study prepared by Bayer AG. 30 p.
45012834 Dorgerloh, M. (1999) MKH 8394 (Free Acid of MKH 7018, a Metabolite of MKH 6561)-Influence on the Growth of Green Alga, Selenastrum capricornutum: Lab Project Number: E 323 1394-5: 109362: DOM 98051. Unpublished study prepared by Bayer AG. 30 p.-Page 58 of 66- 45012835 Batscher, R. (1999) Acute To xicity of MKH 7284 (a Metabolite of MKH 6561) to Earthworms (Eisenia Fetida): Lab Project Number: 736672: 109359. Un published study prepared by RCC Ltd. 32 p. 45012836 Batscher, R. (1999) Acute Toxicity of STJ 4934 (a Metabolite of MKH 6561) to Earthworms (Eisenia Fetida): Lab Project Number: 736661: 109358. Un published study prepared by RCC Ltd. 31 p. 45012837 Heimbach, F. (1999) Influence of MKH 6561 WG 70 on the Reproduction of Earthworms (Eisenia fetida): Lab Project Number: 109370: E 312 1403-4: HBF/RG 282. Unpublished study prepared by Bayer AG. 22 p. 45012838 Schmitzer, S. (1998) Laboratory Testing for Toxicity (Acute Contact and Oral LD50) of MKH 6561 70 WG on Honey Bees (Apis mellifera L.) (Hymen optera, Apidae): Lab Project Number: 4160036: 109386. Unpublished study prepared by Institute for Biological Analysis and Consulting IBACON GmbH. 27 p. 49072701 Shepherd, J.; Christ, M. (2013) Toxicity of MKH6561 (Propoxycarbazone-sodium) Technical during an Acute Oral LD50 with the Canary (Serimus canaria). Project Number: M/449837/01/1/OCR, 07SRLS13C6, EBMIL004. Unpublished study prepared by SynTech Research Laboratory Services, LLC. 35p. 49072702 Christ, M.; Moore, S. (2013) Toxicity of MKH6561 (Propoxycarbazone-sodium) on Reproduction to the Northern Bobwhite Quail (Colinus virginianus). Project Number: M/449836/01/1, EBMIL003/OCR. Unpublished study prepared by SynTech Research Laboratory Services, LLC. 71p.-Page 59 of 66- Appendix A. SWCC Modeling Summa ry for Propoxycarbazone-sodium

Estimated Environmental C oncentrations for Propoxycar bazone are presented in Table A-1 for the USEPA standard pond with the TXwheatOP fi eld scenario. A graphical presentation of the year-to-year peaks is presented in Figure A-1 . These values were generated with the Surface Water Concentration Calculator (SWCC Version 1.106). Critical i nput values for the model are summarized in Tables A-2 and A-3

.

This model estimates that abou t 4.4% of Propoxycarbazone appl ied to the field eventually reaches the water body. The main m echanism of transport from th e field to the water body is by runoff (71.3% of the total transport), followed by spray drift (28.6%) and erosion (0.11%).

In the water body, pesticide dissipates with an effective water column half-life of 131.1 days. (This value does not include diss ipation by transport to the be nthic region; it includes only processes that result in removal of pesticide from the complete system.) The main source of dissipation in the water column is metabolism (effective averag e half-life = 181.8 days) followed by hydrolysis (495 days), photolysis (9397.3 da ys), and volatilization (2.752516E+07 days).

In the benthic region, pesticide dissipates very slowly (537.8 days). The main source of dissipation in the benthic regi on is metabolism (eff ective average half-life = 1053.4 days) followed by hydrolysis (1098.8 days). The pesticide is about evenly distributed in the benthic region between the pore water and sorbed to sediment.

Table A-1. Estimated Environmental Concentrations (ppb) for Propoxycarbazone.
Peak (1-in-10 yr) 2.29

4-day Avg (1-in-10 yr) 2.27

21-day Avg (1-in-10 yr) 2.19

60-day Avg (1-in-10 yr) 2.03

365-day Avg (1-in-10 yr) 0.973

Entire Simulation Mean 0.646

Table A-2. Summary of Model Inputs for Propoxycarbazone.

Scenario TXwheatOP

Cropped Area Fraction 1

Koc (ml/g) 0.4518

Water Half-Life (days) @ 20 °C 199.35

Benthic Half-Life (days) @ 20 °C 1155

Photolysis Half-Life (days) @ 30 °Lat 93.5

Hydrolysis Half-Life (days) 495

Soil Half-Life (days) @ 20 °C 107.463

Foliar Half-Life (days) 35-Page 60 of 66- Molecular Wt 420

Vapor Pressure (torr) 7.1e-11

Solubility (mg/l) 42000

Table A-3. Application Sche dule for Propoxycarbazone.
Date (Mon/Day) Type Amount (kg/ha) Eff. Drift

6/16 Foliar 0.0294 0.95 0.125

10/1 Foliar 0.0294 0.95 0.125

Figure A-1. Yearly Peak Concentrations-Page 61 of 66- Appendix B. Example T-REX Input and Output for Propoxycarbazone-sodium

TREX MODEL INPUTS You must enable macros for this spreadsheet to work correctly

These values will be used in the calculation of exposure estimates for foliar, granular, liquid and/or
seed applications of pesticides.

Chemical Identity and Application Information

Chemical Name: Propoxycarbazone-sodium

Seed Treatment? (Check if yes) FALSE

Use: Agricultural Fallow/Conservation Reserve, Pastures, and Rangeland

Product name and form: % A.I. (leading zero must be entered for formulations <1% a.i.): 100.00%
Application Rate (lb ai/acre) 0.0525 Half-life (days): 35 Application Interval (days):

Number of Applications: 1

Are you assessing applications with variable rates or intervals? no

Assessed Species Inputs (optio nal, use defaults for RQs fo r national level assessments)

What body weight range is assessed (grams)? Birds Mammals

Small 20 15

Medium 100 35 Large 1000 1000-Page 62 of 66- Endpoints

Avian

Endpoint Toxicity value Indicate test species below

LD50 (mg/kg-bw) 2000.00 1

LC50 (mg/kg-diet) 10339.00 2

NOAEL (mg/kg-bw) 2

NOAEC (mg/kg-diet) 268.00 2

Enter the Mineau et al. Scaling Factor 1.15
Mammalian
Acute Study Chronic Study Size (g) of mammal used in toxicity study Default rat body weight is 350 grams 350 350
Endpoint Toxicity value Reference (MRID)

LD50 (mg/kg-bw) 5000.00

LC50 (mg/kg-diet)

Reported Chronic Endpoint 297.10

1 Is dietary concentration (mg/kg-diet) reported from the available chronic mammal study? (yes or no) no

Enter dietary concentration (mg/kg-diet) Estimated Chronic Diet Concentration Equivalent to Reported Chronic Daily Dose 5942 mg/kg-diet based on standard FDA lab rat conversion-Page 63 of 66- Summary of Risk Quotient Calculations Based on Upper Bound Kenaga EECs

Table X. Upper Bound Kenaga, Acute Avian Dose-Based Risk Quotients

Size
Class (grams) Adjust
ed
LD50 EECs and RQs Short Grass Tall Grass Broadleaf Plants Fruits/Pods/Seeds Arthropods Granivore

EEC RQ EEC RQ EEC RQ EEC RQ EEC RQ EEC RQ

20 1440.8
6 14.35 0.01 6.58 0.00 8.07 0.01 0.90 0.00 5.62 0.00 0.20 0.00

100 1834.2
9 8.18 0.00 3.75 0.00 4.60 0.00 0.51 0.00 3.21 0.00 0.11 0.00

1000 2591.0
0 3.66 0.00 1.68 0.00 2.06 0.00 0.23 0.00 1.43 0.00 0.05 0.00

Table X. Upper Bound Kenaga, Subacute Avian Dietary Based Risk Quotients

LC50 EECs and RQs

Short Grass Tall Grass Broadleaf
Plants Fruits/Pods/Seeds Arthropods

EEC RQ EEC RQ EEC RQ EEC RQ EEC RQ

10339 12.60 0.00 5.78 0.00 7.09 0.00 0.79 0.00 4.94 0.00 Size class not used for dietary risk quotients

Table X. Upper Bound Kenaga, Chronic Avian Dietary Based Risk Quotients

NOAEC (ppm) EECs and RQs

Short Grass Tall Grass Broadleaf
Plants Fruits/Pods/Seeds Arthropods

EEC RQ EEC RQ EEC RQ EEC RQ EEC RQ

268 12.60 0.05 5.78 0.02 7.09 0.03 0.79 0.003 4.94 0.02

Size class not used for dietary risk quotients

Table X. Upper Bound Kenaga, Acute Mammalian Dose-Based Risk Quotients

Size
Class (grams) Adjust
ed
LD50 EECs and RQs Short Grass Tall Grass Broadleaf Plants Fruits/Pods/Seeds Arthropods Granivore

EEC RQ EEC RQ EEC RQ EEC RQ EEC RQ EEC RQ

15 10989 12.01 0.00 5.51 0.00 6.76 0.00 0.75 0.00 4.705 0.0004 0.167 2E-05

35 8891 8.30 0.00 3.81 0.00 4.67 0.00 0.52 0.00 3.252 0.0004 0.115 1E-05

1000 3846 1.93 0.00 0.88 0.00 1.08 0.00 0.12 0.00 0.754 0.0002 0.027 7E-06

Table X. Upper Bound Kenaga, Chronic Mammalian Dietary Based Risk Quotients

NOAEC (ppm) EECs and RQs

Short Grass Tall Grass Broadleaf
Plants Fruits/Pods/Seeds/L arge Insects Arthropods

EEC RQ EEC RQ EEC RQ EEC RQ EEC RQ

5942 12.60 0.00 5.78 0.00 7.09 0.00 0.79 0.00 4.94 0.00
Size class not used for dietary risk quotients

Table X. Upper Bound Kenaga, Chronic Mammalian Dose-Based Risk Quotients

Size
Class (grams) Adjust
ed
NOAE

L EECs and RQs Short Grass Tall Grass Broadleaf Plants Fruits/Pods/Seeds Arthropods Granivore

EEC RQ EEC RQ EEC RQ EEC RQ EEC RQ EEC RQ

15 652.98 12.01 0.02 5.51 0.01 6.76 0.01 0.75 0.00 4.71 0.01 0.17 0.00

35 528.33 8.30 0.02 3.81 0.01 4.67 0.01 0.52 0.00 3.25 0.01 0.12 0.00

1000 228.52 1.93 0.01 0.88 0.00 1.08 0.00 0.12 0.00 0.75 0.00 0.03 0.00-Page 64 of 66- Appendix C. Example TERRPLANT (v. 1.2.2) Input and Output for Propoxycarbazonesodium

Table 1. Chemical Identity.

Parameter User Inputs

Chemical Name Propoxycarbazone-sodium

PC code 122019

Use Agricultural Fallow/Conservation Reserve, Pastures, and Rangeland Application Method Broadcast - aerial

Application Form liquid Solubility in Water (ppm) 42000

Table 2. Input parameters used to derive EECs.

Input Parameter Symbol Value (user inputs) Units

Application Rate A 0.0525 a.e.

Incorporation I 1 none
Runoff Fraction R 0.05 none

Drift Fraction D 0.05 none

Table 3. EECs for Propoxycarbazone-sodium. Units in a.e..

Description Equation EEC

Runoff to dry areas (A/I)*R 0.002625 Runoff to semi-aquatic areas (A/I)*R*10 0.02625 Spray drift A*D 0.002625 Total for dry areas ((A/I)*R)+(A*D) 0.00525
Total for semi-aquatic areas ((A/I)*R*10)+(A*D) 0.028875

Table 4. Plant survival and growth data used for RQ derivation. Units are in a.e.. All values are user inputs
Seedling Emergence Vegetative Vigor Plant type EC25 NOAEC EC25 NOAEC

Monocot 0.00045 0.000034 0.00065 0.000063

Dicot 0.00058 0.00021 0.00049 0.00021

Table 5. RQ values for plants in dry and semi-aquatic areas exposed to Propoxycarbazone -sodium through runoff and/or spray drift.*

Plant Type Listed Status Dry Semi-Aquatic Spray Drift

Monocot non-listed 11.67 64.17 5.83

Monocot listed 154.41 849.26 77.21

Dicot non-listed 9.05 49.78 5.36

Dicot listed 25.00 137.50 12.50

*If RQ > 1.0, the LOC is exceeded, resultin g in potential for risk to that plant group.-Page 65 of 66- Appendix D. STIR Results for Propoxycarbazone-sodium



## Input

Application and Chem ical Information Enter Chemical Name Propoxycarbazone
Enter Chemical Use Herbicide Is the Application a Spray? (enter y or n) y If Spray What Type (enter ground or air) ground Enter Chemical Molecular Weight (g/mole) 420.37 Enter Chemical Vapor Pressure (mmHg) 7.10E-11 Enter Application Rate (lb a.i./acre) 0.0525

Toxicity Properties

Bird
Enter Lowest Bird Oral LD 50 (mg/kg bw) 2000 Enter Mineau Scaling Factor 1.15 Enter Tested Bird Weight (kg) 0.178
Mammal

Enter Lowest Rat Oral LD 50 (mg/kg bw) 5000

Enter Lowest Rat Inhalation LC 50 (mg/L) 5.03 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 ) 1.61E-06 Maximum 1-hour Vapor Inhalation Dose (mg/kg) 2.02E-07
Adjusted Inhalation LD 50 1.12E+01
Ratio of Vapor Dose to Adjusted Inhalation LD 50 1.80E-08 Exposure not Likely Significant Maximum Post-treatment Spray I nhalation Dose (mg/kg) 5.55E-03 Ratio of Droplet Inhalation Dose to Adjusted Inhalation LD 50 4.95E-04 Exposure not Likely Significant

Results Mammalian (0.015 kg ) Maximum Vapor Concentration in Air at Saturation (mg/m 3 ) 1.61E-06 Maximum 1-hour Vapor Inhalation Dose (mg/kg) 2.54E-07
Adjusted Inhalation LD 50 2.99E+02
Ratio of Vapor Dose to Adjusted Inhalation LD 50 8.48E-10 Exposure not Likely Significant Maximum Post-treatment Spray I nhalation Dose (mg/kg) 6.97E-03 Ratio of Droplet Inhalation Dose to Adjusted Inhalation LD 50 2.33E-05 Exposure not Likely Significant-Page 66 of 66- Appendix E. SIP Results for Propoxycarbazone-sodium

Table 1. Inputs
Parameter Value
Chemical name Propoxycarbazone Solubility (in water at 25 o C; mg/L) 42000

Mammalian LD 50 (mg/kg-bw) 5000 Mammalian test species laboratory rat Body weight (g) of "other" mammalian species

Mammalian NOAEL (mg/kg-bw) 297.1 Mammalian test species laboratory rat Body weight (g) of "other" mammalian species

Avian LD 50 (mg/kg-bw) 2000 Avian test species northern bobwhite quail Body weight (g) of "other" avian species Mineau scaling factor 1.15

Mallard NOAEC (mg/kg-diet) 268 Bobwhite quail NOAEC (mg/kg-diet) 324

Table 2. Mammalian Results
Parameter Acute Chronic Upper bound exposure (mg/kg-bw) 7224.0000 7224.0000 Adjusted toxicity value (mg/kg-bw) 3845.8028 228.5176 Ratio of exposure to toxicity 1.8784 31.6124

Conclusion* Exposure through drinking water alone is a

potential concern for mammals Exposure through drinking water alone is a

potential concern for mammals

Table 3. Avian Results
Parameter Acute Chronic Upper bound exposure (mg/kg-bw) 34020.0000 34020.0000 Adjusted toxicity value (mg/kg-bw) 1440.8590 13.2962 Ratio of exposure to acute toxicity 23.6109 2558.6322

Conclusion* Exposure through drinking water alone is a

potential concern for birds Exposure through drinking water alone is a

potential concern for birds

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