By: 

## Ecological 

## Risk Assessment Section 3 (New Use on Sorghum) Propazine (PC Code 080808, CASN 139-40-2)

IUPACName: 6-chloro-N2,N4-di-isopropyl-6-methylthio-1,3,5-triazine-2,4-diamine

Pamela 

### M. Hurley, Senior Toxicologist Mark Corbin, Senior Environmental Scientist Ecological Risk Branch 111 Environmental Fate and Effects Division Branch Chief: Daniel Rieder Ecological Risk Branch 111 Environmental Fate and Effects Division Date: November 3,2006

### TABLE OFCONTENTS



### .............................................................................................................. I. EXECUTIVE SUMMARY - 6



### ....................................................................................................... A. Nature of Chemical Stressor 

### 6



### ..................................................................................... B. Potential Risks to Non-target Organisms.. 

### 6



### ..................................................................................... C. Conclusions - Exposure Characterization 

# a

..................................................................................... D. Conclusions -Effects Characterization.. 

# .u

................................................................................................... E. Uncertainties and Data Gaps.. 

# .u

........................................................................................................ 11. PROBLEM FORMULATION 

## .s A. Stressor Source and Distribution


### ................................................................................................

......................................................................................................... I

. Sourceand Intensity 

# .u

.................................................................... 2. Physical/Chemical/Fate and Transport Properties 3. Pesticide Type, Class and Mode of Action


### ............................................................................. &



### ............................................................................................... 4. Overview ofPesticide Usage



### ............................................................................................................................ B. Receptors.. 

# .u

................................................................................................................. 1. Aquatic Effects



### .......................................................................................................... 2. Terrestrial Effects., 

# ..u

............................................................................................................ 3. Ecosystems at Risk 

### 14-



### .......................................................................................................... C. Assessment Endpoints.. .B



### ................................................................................................................... D. Conceptual Model 

## a

.......................................................................................................... 1. Risk Hypotheses 

## .....a

......................................................................................................................... 2. Diagram 

### .d



### ........................................................................................................................ E. Analysis Plan 

# .z

............................................................................................................................... 111. ANALYSIS. 

### ,g



### ............................................................................................................. A. Use Characterization.. .27 -



### ........................................................................................................ B. Exposure Characterization 

### 3



### ................................................................. 1. EnvironmentalFate and Transport Characterization 

### 3



### .......................................................................................... a. Summary of Empirical Data 

### 3 b. Degradation and Metabolism


### ........................................................................................ .?O



### ................................................................................................. c. Transport and Mobility 

### 3



### ............................................................................................................. d. Field Studies .3 -

I



### ................................ e. Review of Published Literature on the Environmental Fate ofPropazine 31



### ............................................................................................. 2. Measures of Aquatic Exposure 

### 3



### .......................................................................................... a. Aquatic Exposure Modeling 3 b. Aquatic Exposure Monitoring and Field Data


### ................................................................... 3



### ......................................................................................... 3. Measures ofTerrestrial Exposure 3C, a. Terrestrial Exposure Modeling


### ...................................................................................... & C. Ecological Effects Characterization


### ........................................................................................... .38 -



### .......................................................................................... 1. Aquatic Effects Characterization - 38



### ........................................................................................................ a. Aquatic Animals 

# .s

.......................................................................................................... b. Aquatic Plants 

# ..a

........................................................................... 2. Terrestrial Effects Characterization.. 

### .B a. TerrestrialAnimals..

........................................................................................ ..44

- b. Terrestrial Plants


### ........................................................................................................ -48 -



### ....................................................................................................... IV. RISK CHARACTERIZATION tjl A. Risk Estimation - Integration ofExposure and Effects Data


### ............................................................. tjl 1. Non-target Aquatic Animals and Plants


### ................................................................................. a. Fish and Invertebrates


### .................................................................................................. 2



### ............................................................................................................ b. Aquatic Plants 

## a 2. Non-target Terrestrial Animals


### ............................................................................................. 

# a

...................................................................................................................... a. Birds.. 

# .s

................................................................................................................ b. Mammals.. 

# .s c. Non-Target Terrestrial-phase Amphibians, Reptiles and Beneficial Invertebrates


### ..................... 3



### .................................. 3. Non-target TerrestrialPlants in Terrestrial and Semi-aquatic Environments 

### 2



### .................................................................................................................... B. Risk Description .& 1. Risks to Aquatic Organisms


### ................................................................................................ - 56



### ..................................................................................................................... a. Animals 5('



### ........................................................................................................... b. Aquatic Plants 

## .s

### ............................................................................................. 2. Risks to Terrestrial Organisms a. Animals..


### ................................................................................................................... j')



### ........................................................................................................ b. Terrestrial Plants @



### .......................................................................................................... 3. Spray Drift Analysis - 64 4. Review of Incident Data


### ..................................................................................................... - 67 5. EndocrineEffects


### ..............................................................................................................

........................................ 6. Federally Threatened and Endangered (Listed Species Concerns.. ..68 -



### .............................................................................................................. a. Action Area 

### .M



### ............................................................................. b. Taxonomic Groups Potentially at Risk 

# a c. Indirect Effects Analysis


### ............................................................................................... 22 d. Critical Habitat


### ........................................................................................................... 

# a e. Co-occurrence Analysis


### ............................................................................................... .73 - C. Description of Assumptions, Limitations, Uncertainties, Strengths, and Data Gaps


### .............................. - 76 1. Uncertainties, assumptions, and limitations associated with models


### ............................................. 

### E 2. Uncertainties, assumptions, and limitation associated with exposure scenarios


### .............................. - 78



### .................................. 3. Uncertainties, assumptions, and limitation associated with the toxicity data 4. Uncertainties and assumptions associated with gaps in environmental fate and toxicity data


### ........... .(O



### ............................................................................................................................ V. Literature Cited 

### .E

......................................................................................................... Appendix A. Propazine 4L Label 

# ..u

................................................................................................. Appendix B. Environmental Fate Studies



### ................................................................................... Appendix C. Aquatic Exposure Model and Results - 93 Appendix D. T-REX Model and Results


### ............................................................................................... 102 Appendix E. TerrPlant Model and Results


### .............................................................................................. Appendix F. Ecological Effects Data


### ....................................................................................................

.......................................................... Appendix G. The Risk Quotient Method and Levels of Concern.. 122



### .......................................................................................................... Appendix H. Data Requirements - 1'5



### ........................................................................................ Appendix I. Environmental Fate Bibliography - 129 Appendix J. Ecological Toxicity Bibliography


### ........................................................................................ - 131

### LIST 

### OF TABLES

Table I-B 1

. Summary ofEnvironmental Risk Conclusions for Aquatic Animals and Plants

........................... 8 Table I-B 2

. Summary ofEnvironmental Risk Conclusions for Terrestrial Animals and Plants

........................ 8 Table I-B 3

. Listed Species Risks Associated with Direct or Indirect Effects

............................................. 9

........................................................ Table I-E 1

. Environmental Fate Data Requirements for Propazine 13 Table I-E 2

. Ecological Effects Toxicity Data Requirements for Propazine

.............................................. 14

................................................................................... Table 11-A 1

. Physical and Chemical Properties of Propazine 16 Table 11-A 2

.Use Information for Propazine 4L (43% a.i.)

....................................................................................... 17 Table 11-E 1

. Assessment Endpoints and Measures of Ecological Effects and Exposure

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

.......................................................... Table 111-B 1

. Physicochemical and Fate Properties ofPropazine 29

............................................................................... Table 111-B 2

. PRZMiEXAMS Input Parameters for Propazine 35 Table 111-B 3

. Estimated Environmental Concentrations (pg/L) ofPropazine in Surface Water

.............................. 36 Table 111-B4

. Terrestrial Bird and Mammal EEC's (Residues)Following Application ofPropazine to Sorghum

...37 Table 111-B 5

. EECs for Terrestrial Plants Located Adjacent to Propazine Treated Sorghum Fields

........................ 38 Table 111-C 1

. Propazine Toxicity Endpoint Values for Assessing Risk to Aquatic Organisms

............................38

....................................................................... Table 111-C 2

. Freshwater Invertebrate Acute Toxicity for Propazine 39

............................................................................... Table 111-C 3

. Freshwater Fish Chronic Toxicity for Propazine 40 Table 111-C4

. Freshwater Invertebrate Chronic Toxicity for Propazine

.................................................................... 40 Table 111-C 5

. EstuarineIMarine Invertebrate Acute Toxicity for Propazine

.......................................................41

...................................................................... Table 111-C 6

. EstuarineiMarine Fish Chronic Toxicity for Propazine 41 Table 111-C 7

. EstuarineIMarine Invertebrate Chronic Toxicity for Propazine

.......................................................... 42

.............................................................................. Table 111-C 8

. Non-Target Aquatic Plant Toxicity for Propazine 42 Table 111-C9

. Non-Target Aquatic Plant Toxicity for the Degradate Deethylatrazine

........................................... 43 Table 111-C 10

. Propazine Toxicity Endpoint Values for Assessing Risk to Terrestrial Organisms

.......................... 43 Table 111-C 11

. Avian Acute Oral Toxicity for Propazine

......................................................................................... 45 Table 111-C 12

.Avian Acute Oral Toxicity for the Degradate Deethylatrazine

.......................................................... 45

................................................................................. Table 111-C 13

. Avian Subacute Dietary Studies for Propazine 45 Table 111-C 14

. Mammalian Acute Toxicity for Propazine

....................................................................................... 46 Table 111-C 15

. Mammalian Acute Toxicity for the Degradate Deethylatrazine

..................................................... 46 Table 111-C 16

. Mammalian DevelopmentaliReproductive Toxicity for Propazine

.................................................. 47 Table 111-C 17

. Mammalian Subchronic and Reproduction Toxicity for the Propazine Degradates

.........................47 Table 111-C 18

. TerrestrialNon-Target Plant Toxicity

............................................................................................... 50 Table IV-A 1

. Toxicity Reference Values Used to Calculate Risk Quotients

........................................................... 51 Table IV-A 2

. Summarized Acute Risks for Aquatic Organisms

.............................................................................. 52 Table IV-A 3

. Summarized Chronic Risks for Aquatic Organisms

........................................................................... 53 Table IV-A 4

. SummarizedAcute Aquatic Plant Risk Quotients

............................................................................. 53 Table IV-A 5

. Mammalian Chronic Risk Quotient Summary

................................................................................... 54 Table IV-A 6

. Terrestrial Plant Risk Quotient Summary for Terrestrial Spray Use on Sorghum

............................. 55 Table IV-B 1

. Comparison of Peak EECs ofPropazine in Surface Water to Aquatic Acute Toxicity Values

..........57 Table IV-B 2

. Comparison of 21- and 60-day EECs ofPropazine in Surface Water to Aquatic Chronic Toxicity Values

................................................................................................................................. 58 Table IV-B 3

. Comparison of Peak EECs ofPropazine in Surface Water to Aquatic Plant Toxicity Values

..........59 Table IV-B 4

. Comparison of Avian Sublethal Values with Predicted Doses onFood Residues

............................. 61 Table IV-B 5

. Mammalian Acute Risk Quotient Summary

....................................................................................... 61 Table IV-B 6

. Comparison of Mammalian Chronic Toxicity Values with Predicted Doses onFood Residues

........63 Table IV-B 7

. Agdrift Input Parameters for Terrestrial Plant Measurement Endpoints

................................ 65 Table IV-B 8

. Summaryof AgDRIFT Modeling Results for Endangered Plant Species

................................. 66 Table IV-B 9
. Summary ofAgDRIFT Modeling Results for Non-Endangered Plant Species

........................... 66 Table IV-B 10

.Listed Species Risks Associated with Direct or Indirect Effects

........................................... 70 Table IV-B 1 1

. SummarizedData from Locates

.............................................................................. 75

### LIST 

### OF FIGURES Figure 11-A1

. Sorghumgrowing areas in the US (USDA,2003 data).

..................................................................... 15 Figure 11-Dl

. Ecological Risk Assessment Conceptual Model for Propazine

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

### I. EXECUTIVE SUMMARY A. Nature of Chemical Stressor The Environmental Fate and Effects Division (EFED) has reviewed the proposed new use ofpropazine 

### (2-chloro-4,6-bis(isopropy1amino)-s-triazine) for weed control in sorghum (grain and sweet). Propazine is part ofthe triazine herbicide family (such as atrazine, cyanazine, simazine) and is very effective at stopping the photosynthetic process in susceptibleplants by binding to specific sites within the plant's chloroplasts. Propazine is currently registered for use on container grown ornamentals in greenhouses (Propazine 4L; EPA Reg. No. 18 12-352). Propazine is formulated as flowable concentrate and proposed applications are via ground or aerial equipment.
For the 1993, 1994, 1995, 1996, and 1997 use seasons, at the request of sorghum growers, EPA granted section 18 emergency exemptions for the use ofpropazine in the five states ofhighest sorghum use: Colorado, Kansas, New Mexico, Oklahoma, and Texas Environmental fate studies indicate that propazine is moderately persistent and mobile. When applied in an outdoor environment, propazine has a high potential to leach into ground water or reach surface waters by runoff. In areas where the soils are highly permeable, the water table is shallow, and sufficient precipitation and/or irrigation occur, the use ofpropazine may result in surface and ground water contamination. In addition, the use ofpropazine on sorghum as specified on the proposed label prohibits use on sand, loamy sand, heavy clay, and high organic matter soils. As such, the risk conclusions contained in this assessment would not apply to these soil types. 

### B. Potential Risks to Non-target Organisms This screeningrisk assessment indicates that at the maximum proposed propazine application rate for sorghum, the chronic Level of Concern (LOC) for freshwater invertebrates inhabiting surface waters adjacent to apropazine treated field is exceeded and these organismsmay be at risk for adverse chronic effects on survival and growth when exposed to propazine in surface runoff andlor leachate as a result of spray application. Based on the available data, low risks are anticipated for freshwater and marinelestuarine invertebrates following acute exposure and to freshwater and marinelestuarine fish and marinelestuarine invertebrates following chronic exposure. Potential risk to freshwater and marinelestuarine fish following acute exposure could not be estimated due to lack of valid toxicity data. Lack of toxicity data do not rule out the possibility ofrisk to fish following acute exposure. There are exceedances ofthe LOCs for endangered vascular and non-vascular aquatic plants for runoffldrifl from ground and aerial spray applications ofpropazine to sorghum. However, there are no exceedances of LOCs for unlisted vascular aquaticplants. There are exceedances of LOCs for unlisted non-vascular aquatic plants, assuming that the maximum predicted propazine concentrations would come in contact with freshwater non-vascular plants. Consequently, endangered vascular and non-vascular plants and non-endangered non-vascular plants inhabiting surface waters adjacent to a treated field would be at risk for adverse effects to growth and development when exposed to propazine as a result ofthe proposed labeled use on sorghum. Although there arecurrently no listed non-vascular plants, there is concern for indirect effects on organisms dependent upon non-vascular plants for survival. Acute avian risk quotients (RQs) were not calculated because the results ofthe toxicity studies indicatethat the acute LD5() and LC5o are greater than highest dose/concentration tested with no mortalities. A qualitative assessment was conducted comparing the estimated Environmental Exposure Concentrations (EECs) with thehighest dose/concentration tested in each study. Thehighest EECs ranged from 4-fold lowerto more than an order ofmagnitude lower than thehighest dose/concentration tested in the acute oral and dietary avian studies. Therefore, the acute risk ofmortality to birds, reptiles and terrestrial-phase amphibians is low. There is,however, a concern for acute sublethal effects (weight loss) as these effects are observed at anticipated EECs. No chronic avian toxicity data are available; therefore, no risks were estimated. Lack of toxicity data do not rule out the possibility ofrisk to birds, reptiles and terrestrial-phase amphibians following chronic exposure. The observed sublethal effects in birds following acute exposure and the observed effects in mammals following chronic exposure increase the uncertainty over the potential risk to birds, reptiles and terrestrialphase amphibians following chronic exposure. The chronic LOC is exceeded for all weight classes ofmammals consuming short grasses, tall grasses, and broadleaf foragelsmall insects at both the maximum and mean predicted residue levels; and for 15and 35 g mammals consuming hitand large insects at the maximum predicted residue levels. Consequently, mammals would be at risk for effects on reproduction and/or growth following chronic exposure to propazine with the proposed labeled use. As with birds, acute mammalian risk quotients (RQs) were not calculated because the results ofthe toxicity study indicated that the acute LD5() is greater than highest dose tested. A qualitative assessment, comparing the estimated Environmental Exposure Concentrations (EECs) with the highest dose tested indicates that there is no concern for acute risk to mammals because the EECs are less than an order ofmagnitude ofthe highest dose tested in the acute mammalian study. For the aerial spray application of propazine and the maximum application rate, the acute LOC was exceeded for nonendangered monocots and dicots located in adjacent areas and in semi-aquatic areas primarily as a result ofrunoff; and for both nonendangered monocots and dicots as a result of spray drift. Likewise, the acute LOC was exceeded for nonendangered monocots in semi-aquatic areas and nonendangered dicots in adjacent and semi-aquatic areas as the result of runoff from ground spray applications. For both ground and aerial spray application, the LOC was exceeded for endangered monocots and dicots located in adjacent and semi-aquatic areas primarily as a result ofrunoff. The LOC for endangered species was also exceeded for monocots and dicots in dry areas exposed to spray drift from aerial applications. Consequently, nonendangered and endangered monocots and dicots inhabiting dry and semi-aquatic areas adjacent to a treated field would be at risk for adverse effects to growth and development following exposureto propazine with theproposed labeled use. Tables I-B1 and 

### I-B2 summarize the environmental risk conclusions for aquatic and terrestrial animals and plants.animals and plants Summarized Risk Characterization and Important Uncertainties No valid acute toxicity data are available. Lack of data does not rule out potential risk. Chronic LOCs are not exceeded for any of the proposed uses. LCSo >highest concentration tested (HCT). Highest peak aquatic EEC 61 times lower than HCT for this use; therefore, concern for acute risk to freshwater invertebrates is low. Applicationrate for Texas scenario needs to be reducedby 46% to 0.65 lb ai/A for the chronic LOC not to be exceeded. For Kansas scenario, rate needs to be reduced by 5% for chronic LOC not to be exceeded. No valid acute toxicity data are available. Lack of data does not rule out potential risk. ChronicLOCs are not exceeded for any of the proposed uses. Acute LOCs are not exceeded for any of the proposed uses. Chronic LOCs are not exceeded for any of the proposed uses. Although no listed non-vascular plants, there is still a concern for indirect effects on organisms dependent upon non-vascular plants for food and shelter. Application rates need to be reduced by 93% for the LOC for aquatic plants not to be exceeded.

Table I-B2. Summary of environmental risk conclusions for terrestrial animals and plants risk conclusions for aquatic Use Patterns with LOC Exceedances
Unknown

None

Chronic LOC exceeded for both Kansas (aerial) and Texas (aerial and ground) scenarios (1.2 lbs aiIA, 1 applicatiodyear). Unknown

None
None

None Acute endangered species exceeded for aquatic non-vascular and vascular plants for Texas and Kansas sorghum scenarios (1.2 lbs ai/A, 1 applicatiodyear). Table I-B1. Summary
Taxa

Freshwater Fish and Aquatic Phase Amphibians

Freshwater Invertebrates

Marine1 Estuarine Fish

Marine1 Estuarine Invertebrates

Aquatic Plants

- of environmental Assessment Endpoint
Acute Risk
Chronic Risk

Acute Risk

Chronic Risk

Acute Risk
Chronic Risk Acute Risk
Chronic Risk

Acute Risk

Summarized Risk Characterization and Important Uncertainties Avian RQs not calculated; acute and LCso>highest dose/concentration tested with no mortalities. Highest EECs range from 4- fold to an order of magnitude less than highest doselconcentration tested. Therefore, acute risk of mortalities is low. Sublethal effects (weight loss) may occur at anticipated EECs. No chronic avian toxicity data available; sublethal effects in birds following acute exposure and observed effects in mammals following chronic exposure increase the uncertainty over the potential risk to birds, reptiles and terrestrial-phase amphibians Taxa

Birds, Reptiles and Terrestrial Phase Amphibians Assessment Endpoint

Acute Risk

Chronic Risk Use Patterns with LOC Exceedances

None

UnknownTable I-B3 summarizes the listed species at risk associated with either direct or indirect effects following application ofpropazine at the requested rates.

Table I-B2. Summary Taxa

Mammals

Non-target Invertebrates

Terrestrial Plants



### Concerns For Federally Listed as Endangered and/or Threatened Species of environmental Assessment

Endpoint

Acute Risk

Chronic Risk

A~~~~ ~i~k

Acute Risk

Table I-B3. Listed species risks associated with direct or indirect effects due to applications of propazine on risk conclusions for Use Patterns with LOC Exceedances

None
Chronic LOC exceeded for 1.2lbs ailA, 1 application/yearwithboth Kansas and Texas scenarios. Not quantitatively assessed.

Acute exceeded for nonendangered monocots and dicots .2 IbsailA, applicatiodyear.

sorghum Listed Taxon Terrestrial and semi-aquatic plants - monocots

Terrestrial and semi-aquatic plants - dicots

Terrestrial invertebrates

Birds

Terrestrial-phase amphibians

Reptiles terrestrial animals and plants Summarized Risk Characterization and Important Uncertainties following chronic exposure. Mammalian RQs not calculated; acute LD50> HDT. Highest EEC an order of magnitude less than the HDT. Therefore, acute risk of mortalitiesis low. Chronic LOC exceeded for all weight classes of mammals consuming short grasses, tall grasses, and broadleafforagelsmall insects; 15 and 35 g mammals consuming fruit and large insects. Propazine is relatively non-toxic with a 96-hr. mortality rate of 2.47% at a dose of 96.69 pghee. Acute risks to terrestrial insects likelyto be low. Acute LOC exceeded for nonendangered monocots and dicots for both ground and aerial spray application (1.2 lbs aiIA, 1 applicationlyear). Nonendangered and endangeredmonocots and dicots inhabiting dry and semi-aquatic areas adjacent to a treated field at risk.

Direct Effects Yes

Yes

No for terrestrial insects; unknown for other terrestrial invertabrates (insufficient data) Possible: no chronic avian data; sublethal effects in acute studies coupled with similar effects in mammalian reproduction study increase uncertainty for birds. Possible: no acute or chronic data and no chronic avian data (see comment for birds) Possible: no acute or chronic Indirect Effects Yes through effects to pollinators (mammals; uncertain with birds, reptiles, terrestrial-phase amphibians) Yes through effects to pollinators (mammals; uncertain with birds, reptiles, terrestrial-phase amphibians) Yes through effects to terrestrial

and aquatic plants (food and habitat) Yes through effects to terrestrial

and aquatic plants (food and habitat), mammals, freshwater invertebrates)
Yes through effects to terrestrial

and aquatic plants (food and habitat), mammals, freshwater invertebrates) Yes through effects to terrestrial

## I Table I-B3. Listed species risks associated with direct or indirect effects due to applications of propazine on 

## I
Listed Taxon Indirect Effects habitat), mammals, freshwater invertebrates) and aquatic plants, mammals, Direct Effects data and no chronic avian data (see comment for birds) Mammals Yes with chronic exposure.
Aquatic non-vascular plants* Aquatic vascular plants Freshwater fish

Aquatic-phase amphibians

Freshwater crustaceans

Mollusks Yes Yes Unknown with acute exposure (no acute data);No after chronic exposure. Unknown with acute exposure (no acute data); using chronic data on fish as surrogate -No after chronic exposure. Using data on daphnia as surrogate -No after acute exposure and Yes after chronic exvosure.

Marinelestuarine fish freshwater invertebrates. No No Yes through effects to terrestrial plants (stream quality), aquatic

plants (food and habitat) and freshwater invertebrates (food) Yes through effects to terrestrial plants (stream quality), aquatic

plants (food and habitat) and freshwater invertebrates (food) Yes through effects to terrestrial plants (stream quality), aquatic

plants (food and habitat) and other freshwater invertebrates
No after acute exposure; Using chronic data on crustaceansas

surrogate - NOafter chronic

Marinelestuarine crustaceans

As noted above, propazine may not be applied to selected soils and as such therisk conclusions do not applyto locations where sorghum is grown on these soils. More details on the risk conclusions can be found in the Executive Summaryofthe Ecological Risk Science Chapter for propazine. (food). Yes through effects to terrestrial plants (stream quality) and aquaticplants (food and habitat). exposure. Unknown: no acute data No after chronic exposure.



## L

C. Conclusions -Exposure Characterization Yes through effects to terrestrial plants (tributarylestuary quality)

and aquatic plants (food and
No after acute andlor chronic exposure.
invertebrates (food).

Propazine, like the other triazine chemicals, is weakly basic (pKa = 

### 1.85at 22OC), can be easily protonated at low soil pH values, and is likely to exist as a neutral species at soil pH values more than two pH units above the pKa. Adsorption ofprotonated propazine is pH-dependent, with a maximum adsorption at or near the pKa. Soil organic matter plays an important role in the adsorption ofpropazine and other s-triazines, affecting their movement in soil. habitat) Yes through effects to terrestrial plants (tributarylestuary quality), aquatic plants (food and habitat) and other marinelestuarine * At the present time no aquatic non-vascular plants are included in Federal listings of threatened and endangered species. The taxono~nic group is included here for the purposes of evaluating potential contributions to indirect effects to other taxa and as a record of exceedences should future listings of non-vascular aquatic plants warrant additional evaluation of Federal actions.Theherbicide propazine is expected to be persistent and mobile in most soils, and it is resistant to breakdown by hydrolysis, photolysis, or biodegradation. Propazine does not adsorb as stronglyto soil particles as other triazine herbicides. In most soilsused in batch equilibrium studies, especially sand and sandy loam soils, it binds weakly to soil particles. Likewise, studies have shown that depending on soil temperature, moisture, and pH, it can become unbound. It is therefore very likely that in areas where soils are highly permeable, the water table is shallow, or where there is irrigation and/orhigh rainfall, the use ofpropazine may result in ground water contamination. Routes of aquatic exposure evaluated in this screening risk assessment focused on deposition, runoff and spray drift from aerial and ground applications ofpropazine. The propazine exposure characterization, combined the environmental fate data with the Tier I1 models Pesticide Root Zone Model (PRZM) version 3.12beta and Exposure Analysis Modeling System (EXAMS) version 2.98 linked to simulate the transport ofthe pesticide offthe field, and to estimate EECs in a standard pond based on thepropazine aerial and ground applications at the proposed maximum application rate for sorghum (1.2 lb a.i./acre).
Routes of exposure for the terrestrial assessment ofbirds and mammals were developed using theT-REX (Ver.1.2.3) model to estimate propazine residues on food types as the result of application to sorghum. Likewise, EECs for non-target terrestrial plants were estimated for broadcast spray application using the TerrPlant (Ver 1 .O) model in conjunction with AgDrifi (Ver. 2.0.1). AgDrifi provides further refinement of spray drift dispersion and deposition to plants located in proximity to treated fields ortreated water bodies. There were no reported incidents from propazine use recorded in the Ecological Incident Information System (EIIS) as ofJune 2006. 

### D. Conclusions -

### Effects Characterization The submitted acutetoxicity studywith a freshwater invertebrate (daphnid) provides a 48-hr EC50value of >5.32 pprn ai (NOAEC 5.32 pprn ai, highest concentration tested) for the TGAI. No valid acute freshwater fish studies are available for propazine. For freshwater fish (early life-stage or a full life-cycle test), propazine induced a significant reduction in length in fathead minnows with aNOAEC of0.72 mg ai/L. Likewise, propazine induced reductions in growth (length and weight) in daphnids with a NOAEC of 0.047 pprn ai. Propazine is categorized as moderately toxic to the mysid shrimp, based on mortality and sublethal effects (LC50 =4.20 pprn ai). Propazine is categorized aspractically non-toxic to the eastern oyster at the limit of solubility with an EC50 >3.72 mg ai/L. In an early life-stage study with sheepshead minnow, propazine affected embryo survival and hatching success at 2.59mg ai/L with a NOAEC of 1.34mg ai/L. This study was used to assess the chronicrisk ofpropazine to estuarine/marine fish. For the life-cycle toxicity study with estuarinelmarine invertebrates, propazine induced significant effects to growth and reproduction at 0.706 pprn ai in mysid shrimp with a NOAEC of 0.269pprn ai. Notoxicity studies were submitted by the registrant to assess the acuterisk ofpropazine to estuarinelmarine fish species. Aquatic plant toxicity studies with propazine provide an ECsoof 0.10ppm ai for freshwater vascular plants (duckweed) with a NOAEC of 0.022 ppm ai,based on frond density. The lowest ECjofor freshwater non-vascular plants (diatom) is 0.0248 ppm ai with a NOAEC of 0.0065 ppm ai, based on cell density. Available acute toxicity data indicate propazine is at most, slightly toxic to birds. The upland gamebird acute oral LDsovalue was >1,640 mg aikg. There were no mortalities. A NOAEL was determined to be 244 mg ailkgbased on weight loss. The acute dietary LCjoswere >4,930 ppm and >5,140 for bobwhite quail and mallard, respectively. No avian reproduction studies were submittedby the registrant. Propazine is categorized as practically non-toxic to small mammals on an acute oral basis (LD5Ovalue >5,050 mg/kg). In a 3-generation reproduction study with rats, no treatmentrelated effects on reproduction were observed; consequently, the NOAEL for reproductive toxicity was 250 mg/kg bwlday, the highest dosetested. The parentalloffspring NOAEL was 5 mgkg/daybased on decreased body weights in both sexes. Terrestrial plant toxicity studies with monocots and dicots indicate that seedling emergence and vegetative vigor are severely impacted by exposure to propazine. Seedling emergence, based on shoot weight, was adversely impacted in monocots (onion) at an EC2sof 0.035 lb ai/A and in dicots (lettuce) with an EC25 of 0.016 Ib ai1A. Vegetative vigor in monocots, based on shoot weight, was adversely impacted in monocots (wheat) at an EC2jof 0.046 Ib ai/A and in dicots (cucumber) at an EC25 of 0.10 lb ai1A. The observed effects to monocots and dicots included stunting, chlorosis, necrosis, and plant death. 

### E. Uncertainties and Data Gaps There are a number of areas of uncertainty in the terrestrial and the aquatic organism risk assessment that could potentially cause an underestimation ofrisk. First, this assessment accounts only for exposureofnon-target organisms to propazine, but not to its degradation products. Therisks presented in this assessment could be underestimated if degradates also exhibit toxicity under the conditions ofuse as stated on the label as limited data are available concerning the toxicity ofthe degradates. Second, the risk assessment only considers the most sensitive species tested from a limited set oftoxicity studies conducted with relatively few species and only considers a subset ofpossible use scenarios. For the aquatic organism risk assessment, there areuncertainties associated with the PRZMIEXAMS models, input values, and the use of surrogate scenarios. The potential impacts ofthese uncertainties are outlined in the Aquatic Exposure, the Terrestrial Exposure and the Risk Characterization sections ofthis document. Additional uncertainty results from the lack ofinformation and/or data in several components ofthis ecological risk assessment, as follows.Acute risks for freshwater fish were not characterized because the submitted study was determined to be invalid based on solubility issues. 

### A high degree of uncertainty exists for the freshwater toxicity data for propazine until it can be shown that the results reflect that the tests were conducted up to the limit of solubility or provide a definitive median lethal concentration. An acceptable study will improve the certainty of the ecological risk assessment. Chronic risk to avian species was not characterized because no studies with the TGAI were submitted. Sublethal effects in the acute avian studies coupled with similar effects observed in the mammalian reproduction studyincrease the uncertainty of effects in birds following chronic exposure. Current data are not available to assess potential risk ofpropazine degradates to aquatic fish and invertebrates and terrestrial plants.
Fate studies indicate propazine is persistent and mobile raising concerns about the impact on groundwater and surface water. The field dissipation studiesthat have been submitted are considered unacceptable or supplemental resulting in a significant uncertainty for this transport pathway. To address this uncertainty, studies are needed to comprehensively ascertain the mobility ofpropazine and its degradates under field conditions. No aerobic or anaerobic aquatic metabolism studies are available for use in this assessment. Therefore, EFED has made an assumption that propazine is two times as persistent in aerobic aquatic environments as it is in aerobic soil. Data on the aquatic metabolism ofpropazine will be needed to address this uncertainty. Tables I-El and I-E2 summarize the environmental fate and ecological toxicity data gaps for propazine and the value of additional testing.

Terrestrial Field(rainbow trout) (bluegill sunfish) class indicate that LCs0is likely sufficiently high not to exceed acute LOC

72-2

72-3a

72-4a
72-4d Freshwater invertebrate acute ECSo (daphnia)

Estuarineimarine fish acute LCjo (sheepshead minnow)
Freshwater fish early life stage (fathead minnow) Estuarineimarine invertebrate life cycle (mysid) for endangered species. Pending. A study has been reviewed but not finalized by the Agency (MRID442873-05). The study is scientifically sound but does not fulfill guideline requirements because daphnids were not exposed up to 100ppm ai. Consequently, the acute toxicity of propazine to freshwater invertebrates cannot be categorized. If it can be shown that the test was conducted up to the limit of solubility, the study could beupgraded to acceptable. However, for these requested uses, a comparison of thehighest concentration tested in the daphnid study with the peak EEC for the proposed uses shows that there were no effects in daphnids at concentrations 61 times higher than the highest peak EEC. Medium. No studies available. Chronic toxicity NOAECILOAEC from sheepshead minnow study plus a comparison with chemicals from similar class indicate that LCjois likely sufficiently high not to exceed acute LOC for endangered species. Low. The study was classified as supple~nental because pH and hardness exceeded recommended levels, potentially affecting solubility. Low. The study was classified as supplemental dueto deviations in study design.11. PROBLEM FORMULATION A. 

### Stressor Source and Distribution 1. 

### Source and Intensity

Figure 11-A1. Sorghum growing areas in the US (USDA, 2003 data). Theproposed use ofpropazine 

### (2-chloro-4,6-bis(isopropylamino)-s-triazine) is for weed control in sorghum (grain and sweet). Theproposed label allows one application per crop cycle (growing season) with the maximum application rate for sorghum of 

### 1.2 Ib ailacre (A). Figure I1.a. 1.depicts areas in the US where sorghum was grown and harvested in 

### 2003 thus providing an indication oflikely propazine use areas. Potential use areas are indicated in the Midwest states of Colorado, New Mexico, Kansas, Nebraska, Oklahoma, Texas and South Dakota, southern regions ofArizona and California, along the Mississippi river valley and along the eastern coastal regions of North Carolina and Maryland. Propazine is currently registered for use on container grown ornamentals in greenhouses (Propazine 

### 4L; EPA Reg. No. 1812-352). 

### 2. PhysicaVChemicaVFate and Transport Properties Propazine is a colorless crystalline solid. It is stable in neutral, slightly acid, or alkaline media, but is hydrolyzed by stronger acids and alkalis. It is nonflammable and non corrosiveunder normal use conditions, however may bum if exposed to heat or flame. Thermal decomposition may produce toxic oxides of carbon and nitrogen, and toxic andcorrosive fumes ofchlorides. Table 11-A1provides a summary of someproperties for propazine. Propazine is expected to be moderately persistent and mobile in most soils, and it is resistant to breakdown by hydrolysis, photolysis, orbiodegradation. Batch equilibrium experiments suggest that propazine is mobile, with Freundlich 

### Kd values ranging from 0.67 to 3.19 in two separate studies involving 8 soil textures. The

### LC values ranged from 65to 268 in these same studies. The mobility ofpropazine is also noted in the supplemental terrestrial field dissipation studies suggesting that propazine dissipates slowly from the upper 6 inches (half-lives of 51 days in TX, and 7 to 58 days in NC, <30 to 149days in 

### NY, <3 1days in CA, and 60 to >357 days in 

### NE) and may leach to ground water. It has also been reported in the literature that if released to soil, propazine will persist longer in dry or cold conditions or other conditions which inhibit biological and chemical activity (Worthing, C.R., ed., 1983. "The pesticide manual: A world compendium. Croydon, England: The British Crop Protection Council"). Therefore, it is very likely that the use ofpropazine may result in groundwater and/or surfacewater contamination in areas where soils are highly permeable, the water table is shallow, or where there is irrigation and/or high rainfall. Volatility and airphotolysis are not expected to be major routes ofdissipation dueto the low vapor pressure (2.9 

### x 10'~ torr at 20°C).

Common name: Propazine Chemical name: 

### 2-chloro-4,6-bis(isopropy1amino)-s-triazine CAS number: 139-40-2 Trade names: Propazine 

### 4L

3. Pesticide Type, 

### Class and Mode ofAction Propazine is part ofthe triazine herbicide family (such as atrazine, cyanazine, simazine) and is very effective at stopping the photosynthetic process in susceptible plants by binding to specific sites within the plant's chloroplasts. The mode of action is inhibition ofphotosynthesis by stopping electron flow in Photosystem 11, which in 

### turn inhibits theformation and release of oxygen. Currently, Griffin L.L.C. is seeking registration for propazine as a selectiveherbicide for control ofweeds in sorghum. 

### 4. Overview of 

### Pesticide Usage Propazine has been previously registered for use on sorghum and in greenhouse ornamentals. However, due to economic considerations, in 1990,the propazine registration for sorghum was voluntarily cancelled by the Registrant (then Ciba-Geigy). For the 1993,1994,1995,1996,and 1997 use seasons, at the request of sorghum growers, EPA granted section 18 emergency exemptions for the use ofpropazine to the five states ofhighest sorghum use: Colorado, Kansas, New Mexico, Oklahoma, and Texas. Currently, propazine is only registered for use on container grown ornamentals in greenhouses. Propazine is proposed for use as a selective herbicide in sorghum before planting, at planting and after crop (sorghum) emergence for control ofmany annual broadleafweeds such as pigweed, devil's claw, carpetweed, smartweed, kochia, morningglory, ragweed, velvetleaf and others. Application can be made via ground sprayer or aerial broadcast for sorghum.End use formulations of propazine that are manufactured by Griffin L.L.C. include a 98% wettable powder technical product and a 43% flowableconcentrate end use product (Propazine 4L). Table 11-A2liststhe food and non-food uses (based on application and use rates) for propazine according to the proposed label information.

In addition, the use ofpropazine on sorghum as specified on the proposed label prohibits use on sand, loamy sand, heavy clay, and high organic matter soils. As such, therisk conclusions contained in this assessment would not apply to these soil types. Table 11-A2. Use Information for Propazine4L (43%a.i.)



### B. Receptors Crop (Application type) Container-grown ornamentals in greenhouses (ground)

Sorghum -Grain and Sweet (ground and aerial)

For the screeninglevel risk assessment onpropazine, toxicological data generated on representative test species belonging to broad taxonomic groups are summarized, then utilized in an assessment ofrisk for each group. These data are obtained from registrantsubmitted studies. Table 11-El in the Analysis Plan section provides the taxonomic groups and surrogatetest species evaluated for ecological effects in the screening-level risk assessment for propazine. Within each ofthese very broad taxonomic groups, an acute and/or chronic measure of effect is selected from the available test data. A Soil Texture Sand, Loamy Sand, and Sandy Loam
Loam, Silt, Silty Loam, Silty Clay Loam, and Sandy Clay Loam Sandy Clay, Clay Loam, Silty Clay Loam, and Peat-Lite Mixes Sand, Loamy Sand, Heavy Clay, High OM Sandy Loam, Loam, Silt Loam, and Clay Loam Rate 0.01 17lb ai/1000ft2

0.0195 Ib ai/lOOOftL
0.0352 Ib ai/1000ft2
Do not use
1.2 lb ailAcomplete discussion of all toxicity data available for this risk assessment for propazine and theresulting measurements of effect selected for each taxonomic group are included in Appendix F. 1. Aquatic Effects Spraydrift and runoff to adjacent bodies ofwater are themost likely sources ofpropazine exposure to nontarget aquatic organisms, including endangered and threatened species. In addition, the mobility ofpropazine in soils indicates that in areas where soils are highly permeable, the water table is shallow, or where there is irrigation and/orhigh rainfall; leaching to groundwater may occur, which may result in exposure to aquatic organisms where a potential hydrological connection to surface water bodies exists. Propazine is not expected to bioaccumulate in aquatic organisms or to adsorb to sediments; consequently risk to benthic-dwelling organisms shouldbeminimal. For propazine, effects on aquatic organisms are estimated from acute and chronic laboratory studies submitted to the Agency by the registrant. Thetoxicity data for propazine will be used to assess risk to fish, aquatic invertebrates, and aquaticplants. Acute data are available for freshwater invertebrates [water flea (Daphnia magna)] and marinelestuarine invertebrates [eastern oyster (Crassostrea virginica) and saltwater mysid (Mysidopsis bahia)]. Reproductive or growth effects from chronic exposure are estimated from studies conducted with fish and invertebrates. For propazine, data are availableto evaluate the chronic effects on freshwater fish and invertebrates and estuarine/marinefish and invertebrates. Toxicity data are available for aquaticvascular plants (duckweed, Lemna gibba); non-vascular algae (green algae, Selenastrum capricoi.nuturn; blue-green algae,Anabaenaflos-aquae); and freshwater and marine diatoms (Naviculapelliculosa, Skeletonema costatum). 2. Terrestrial Effects Ground deposition from spray application and spray drift with resulting residues on foliage and on flowers and seeds are the most likely sources ofpropazine exposure to nontarget terrestrial organisms, including endangered and threatened species. Current data were not provided to determine the potential exposure to birds, mammals, and pollinators from residues on foliage, flowers, and seeds. The effect of acute exposureto propazine on all bird species is estimated from acute oral and dietary studies on either bobwhite quail (Colinus virginianus) and/or mallard duck (Anusplatyrhynchos). These species also act as surrogates for reptiles and terrestrial-phase amphibians. Propazine acute oral toxicity effects data are available for thebobwhite quail only. Acute dietary toxicity data are available for both bobwhite quail and mallard duck. No toxicity studies have been conducted to determine the potential chronic effects to birds or the effect of residues to pollinators. Effects on mammals are estimated from acute and chronic laboratory studiesreviewed by the Registration Division (RD) and Health Effects Division (HED), respectively. Propazine effects data for mammals are available for acute (rat) and chronic [(reproductive(rat) and developmental (rat and rabbit))] oral exposure. An additional source of exposureto propazine could be in puddled waters on treated fields throughpreening and grooming, involving the oral ingestion ofmaterial from the feathers or fur. Propazine is expected to be moderately persistent and mobile in most soils and isresistant to breakdown by hydrolysis, photolysis, or biodegradation. Consequently, exposureto birds, small mammals, and soil invertebrates through dermal contact or ingestion of soils could occur. Exposure to propazine via inhalation would be expected to be low due to its low vapor pressure. Currently, screening level assessments do not address exposure via the dermal and inhalation routes (see Assumptions, Limitations, Uncertainties, Strengths and Data Gaps section for further explanation). Spray drift presents a potential risk to non-target plants inhabiting edge habitats adjacent to target fields and riparian vegetation along streams and/or ponds in closeproximity to sprayed fields. In addition, uptake in plant roots could occur through ground spray application. Studies (seedling emergence and vegetative vigor) were submitted to evaluate the effects ofpropazine to terrestrial monocots and dicots. 3. Ecosystems at Risk The proposed uses of propazine could result in exposure to aquatic and terrestrial organisms inhabiting flowing, non-flowing or transient freshwater bodies and to wildlands (forests, wetlands and ecotones; such as edge and riparian habitats). For uses in coastal areas, aquatichabitats also include marine ecosystems, including estuaries. For both terrestrial and aquatic animal species, direct and indirect acute and chronic exposures are considered. For screening level assessment purposes, risk will be assessed to aquatic animals and plants assumed to occur in small, static ponds receiving runoff and drift from treated areas. Aquatic animal species ofpotential concern include freshwater fish and invertebrates, estuarinelmarine fish and invertebrates, and amphibians. Aquatic plant species ofconcern include vascular and non-vascular plants. The terrestrial ecosystems potentially at risk include the treated area and areas immediately adjacent to the treated area that might receive drift (wind dispersion) or runoff, and might include other cultivated fields, fence rows and hedgerows, meadows, fallow fields or grasslands, woodlands, riparian habitats, wetlands, and other uncultivated areas. For screeninglevel assessment purposes, risk will be assessed to terrestrial animals assumed to exclusively occur in the treated area. Terrestrial animal species of potential concern include birds, mammals, beneficial invertebrates, and earthworms. Propazine is readily absorbed through the foliage and roots ofplants; consequently, it could be injurious to non-target plant speciesby drift, runoff, or root and foliar uptake. Terrestrial plant species of concern include monocots, dicots, and semi-aquatic plant species.
C. Assessment Endpoints The typical assessment endpoints for screening-level pesticide ecological risk assessments are reduced survival and reproductive and growth impairment for both terrestrial and aquatic animal species. For terrestrial and semi-aquatic plants, the screening assessment endpoint is the perpetuation ofpopulations ofnon-target species. Existing testing requirements have the capacity to evaluate emergence of seedlings and vegetative vigor. Although it is recognized that these endpoints may not address allterrestrial and semi-aquatic plant life cycle components, it is assumed that impacts at emergence and in active growth have the potential to impact individual competitive ability and reproductive success. For aquatic plants, the assessment endpoint is the maintenance and growth of standing crop or biomass. Measures of effect for this assessment endpoint focus on algal and vascular plant growth rates and biomass measurements. This ecological risk assessment considers single application at the maximum propazine application rate to fields that have vulnerable soils to estimate exposure concentrations. This assessment isnot intended to represent a site- ortime-specific analysis. Instead, it is intended to represent high-end exposures at a national level. Likewise, the most sensitive toxicity endpoints areused from surrogate test species to estimate treatment-related direct effects on acutemortality and chronic reproductive, growth and survival assessment endpoints. Toxicity tests are intended to determine effects of pesticide exposure onbirds, mammals, fish, terrestrial and aquatic invertebrates, and plants. Thesetests include shortterm acute, subacute, and reproduction studies and are typically arranged in a hierarchical or tiered system that progresses from basic laboratory tests to applied field studies. The toxicity studies are used to evaluate the potential of a pesticide to cause adverse effects, to determine whether further testing isrequired, and to determine the need for precautionary label statements to minimize the potential adverse effects to non-target animals and plants (CFR 40 

## 9 158.202,2002). A summary ofmeasurements of effect selected to characterize potential ecological risks associated with exposure to propazine areprovided in Table 11-El in the Analysis Plan section.
In order to protect threatened and endangered species, all assessment endpoints are measured at the individual level. Measuring endpoints at the individual level also provides insight about risks at higher levels of biological organization (e.g. populations and communities). For example,pesticide effects on individual survivorship have important implications for both population rates of increase and habitat carrying capacity. The ecological relevance of selecting the above-mentioned assessment endpoints is as follows: 1) complete exposure pathways exist for these receptors; 2) the receptors may be potentially sensitiveto pesticides in affected media and in residues onplants, seeds, and insects; and 3)the receptors could potentially inhabit areas where pesticides are applied or areas where runoff andlor drift may impact the sites. 

### D. Conceptual Model 1. Risk Hypotheses Risk hypotheses are specific assumptions about potential adverse effects (i.e., changesin assessment endpoints) and may be based on theory and logic, empirical data, mathematical models, or probability models (EPA, 1998). For this assessment, the risk is stressor-linked, where the stressor is the release ofpropazine to the environment. The following risk hypothesis is presumed for this screening level assessment: Based on the mobility and persistence ofpropazine, the mode ofaction, and the-food-web ofthe target aquatic and terrestrial ecosystems, propazine has thepotential to cause

### reduced survival, and reproductive and growth impairmentfor both 

### aquatic and tei*restrialanimal and

### plant species. Adequate protection is defined as protection of growth, reproduction, and survival of aquatic and terrestrial ecological populations, and individuals oflisted species, asneeded. 2. 

### Diagram All potential routes of exposure are considered and are presented inthe conceptual site model. The conceptual site model shown in Figure 11-Dl for ground and aerial spray applications generically depicts the potential source ofpropazine, release mechanisms, abioticreceiving media, biological receptor types, and effects endpoints ofpotential concern. In order for a chemical to pose an ecological risk, it must reach ecological receptors in biologically significant concentrations. An exposure pathway is the means by which a contaminant moves in the environment from a source to an ecological receptor. For 

### an ecological exposurepathway to be complete, it must have a source, a release mechanism, an environmental transport medium, a point of exposure for ecological receptors, and a feasible route of exposure. In addition, the potential mechanisms oftransformation (i.e., which degradates may form in the environment, in which media, and how much) must be known, especially for a chemical whose metabolitesldegradates are ofgreater toxicological concern. The assessment of ecological exposure pathways, therefore, includes an examination ofthe source and potential migration pathways for constituents, and the determination ofpotential exposure routes (e.g., ingestion, inhalation, dermal absorption).Source: Exposure Media Residues
I -------

### --

### -

## -

Exposure 

# I I I Dietary Uptake 

# I Direct Ingestion Dietary Uptake Direct Ingestion

Direct 

# C

*Plant growth abnormalities *Lethality Receptor 

### \, Pollinators \ Non-Target

Plants

TerrestrialAnimals: *Lethal and non-lethal effects *Reproductiveldevelopmental

effects *Effects on foraging behavior

I I Figure 11-Dl. Ecological Risk Assessment Conceptual Model for Propazine Aauatic Animals and Plants: *Effects to survival, growth, and

reproduction *Reductions in celldensity1

biomass in aquatic plants I I I I Ter. Herbivores, Birds, Mammals,

Altered Aquatic CommunityAssemblages: Effectsto riparian habitat availability Effectsto species abundancetdiversity Changes in ~hvsical/chemical parameters Altered Terrestrial Community Assemblages:Non-Target Plants (edge and riparian habitat)

Indirect Reduced food supply and edge habitat availability Algae, Aquatic Vascular Plants, Aquatic Vertebrates, Aquatic Invertebrates Terrestrial Vertebrates & Invertebrates

### E. Analysis Plan The Agency's new use science chapter for propazine consists of a deterministic screening level risk quotient analysis. The aquatic and terrestrial assessments focus on the proposed agricultural use ofpropazine for weed control in sorghum with the highest application rate (1.2 lb ai/A) as specified by the current label (as of 8/01/05). Potential exposure pathways (i.e., runoff and spray drift) result from ground and aerial application of aqueous propazine formulations to sorghum. The Agency reviewed the available laboratory environmental fate data submitted in support ofthe proposed new use ofpropazine to determine propazine persistence and mobility. Based onthis data, the Agency developed its quantitative aquatic assessment of propazine exposure using the PRZMIEXAMS model to represent potential propazine use areas. Likewise, terrestrial wildlife may be exposed to propazine through theplant or animal material that they contact or consume as food. For ground and aerial spray applications ofpropazine, exposure to terrestrial wildlife was estimated by relating food item residues to pesticide application using the Kenaga nomogram as modified by Fletcher (Hoerger and Kenaga, 1972; Fletcher et al., 1994). A computer model 

### (T-REX, Version 1.2.3) was used to predict degradation of residues on foliar surfaces and insects. For mammals, the residue concentration was converted to a daily oral dose based on fractions ofbody weight consumed daily. Terrestrial non-target plant exposure characterization employed runoff and spray drift scenarios based on propazine use on sorghum and were estimated using OPP's TerrPlant model (Version 1.O) as well as the AgDrift2.0.1 model to provide further refinement of spray drift dispersion and deposition to terrestrial plants located in proximity to treated fields. Themost sensitive aquatic and terrestrial eco-toxicological values from studies submitted to the Agency were used in this quantitative assessment. Risks were estimated based on a deterministic approach, where a single point estimate oftoxicity is divided by 

### an exposure estimate to calculate a risk quotient (RQ). The acute and chronic RQ values for each taxonomic group identified as an assessment endpoint were compared to the Agency's Levels of Concern (LOCs). LOCs serve as criteria for categorizing potential risk to non-target organisms. RQ values were calculated in therisk estimation section for each endpoint, and characterization and interpretation ofrisk is described in the risk description. Risks for each taxonomic group were described based on available lines of evidence from registrant-submitted studies, open literature, and incident reports. In addition, a preliminary assessment of listed species of concern was also completed. No degradates were included in this assessment. Onemajor degradate detected at > 10% of applied, hydroxyl-propazine 

### (2-hydroxy-4,6-bis(isopropy1amino)-s-trine) was not included in this assessment due to the fact that it was determined to not be of toxicological concern in the assessments for atrazine and simazine and the fact that no environmental fate data was available. The minor degradates, desethylatrazine (2-amino4-chloro-6-isopropylamino-s-triazine or DEA) and 2,4-diamino-6 chloro-s-triazine (DACT), were not included in this assessment mostly due to their low detection in the laboratory soil metabolism studies and in theterrestrial field studies (less than 

### 5% ofTotal Applied Radioactivity (TAR)). Laboratory and field studies indicate that 

### DEA and 

### DACT, if formed in the environment, would not bepresent nor would persist at any significant concentration compared to parent propazine to adversely impact the results of the ecological risk assessment. In addition, toxicity studies indicate that the degradates exhibit similar toxic responses in birds, mammals and aquatic plants as the parent propazine. Table 11-El summarizes the assessment endpoints and measures of ecological effects 

### and exposure used in the ecological risk assessment for propazine.Table 11-El. Assessment Endpoints and Measures of Ecological Effects and Exposure for Propazine

Taxonomic Group Assessment Endpoint Surrogate Species and Measures of Exposure Measures of Ecological Effect

Reproduction and growth

Mammals

Freshwater fish

Freshwater invertebrates

Estuarinelrnarine fish

Estuarinelmarine invertebrates Survival

Reproduction and growth

Survival

Reproduction and growth

Survival

Reproduction and growth

Survival

Reproduction and growth

Survival

Reproduction and growth Laboratoryrat acute oral LDJ0 Laboratory rat oral reproduction chronic NOAEC and LOAEC Rainbow trout and bluegill sunfish acute LCso(no valid study available) Fathead minnow chronic (early life-stage) NOAEC and LOAEC

Water flea (and other freshwater invertebrates) acute EC50

Water flea (life LOAEC
Sheepshead minnow acute LC5,) (no study available)
Sheepshead (early life-stage) NOAEC and LOAEC
Eastern oyster acute ECSo and mysid acute LC50

chronic and LOAEC items (foliar)

peak EEC

60-day average EEC

Peak EEC

2 1-day average EEC

peak EEC

60-day average EEC

peak EEC

2 1-day average EEC

# I Table 11-El. Assessment Endpoints and Measures of Ecological Effects and Exposure for Propazine 

# I

Key Uncertainties and Information Gaps "Birds

The following uncertainties and information gaps were identified aspart ofthe problem formulation for propazine: $ Acute risks for freshwater fish were not characterizedbecause the submitted study was determined to be invalid based on solubility issues. Uncertainty exists for the freshwater toxicity data for propazine until it can be shown that the tests were conducted up to the limit of solubility. b~reshwater fish may be surrogatesfor amphibians (aquaticphase). 'Four species of two families of monocots, of which one is corn; six species of at least four dicot families, of which one is soybeans. LDjo= Lethal dose to 50% of the test population; NOAEC = No observed adverse effect concentration; LOAEC = Lowest observed adverse effect concentration; LCjo= Lethal concentration to 50% of the test population; ECjolEC2,= Effect concentration to 50%125% of the test population.

$ Chronic risk to avian species was not characterized because no studies with the TGAI were submitted. Taxonomic Group

Terrestrial plants "

Insects

Aquatic plants and algae

$ Current data were not available to determine the potential exposure to birds, mammals, and pollinators from residues on foliage, flowers, and seeds. represent surrogates for amphibians (terrestrial phase) and reptiles. Surrogate Species and Measures of Ecological Effect

Monocot and dicot seedling emergence and vegetative

vigor EC25,ECo5, and NOAEC values Honeybee acute contact LDSO (no study available) Algal and vascular plant (i.e., duckweed) ECSo and NOAEC values for growth rate and biomass

measurements Assessment Endpoint (Abundance)

Survival and growth

Survival (not quantitatively assessed)

Survival and growth

$ No field toxicity studies are available. Spray drift presents a potential risk to nontarget plants inhabiting edge habitats adjacent to target fields and riparian vegetation along streams and/orponds in close proximity to sprayed fields. Measures ofExposure

Estimates ofrunoff and spray drifi to non-target areas

Maximum application rate

peak EEC$ Current data were not provided to determine the potential risks ofpropazine degradatesto fish and aquatic invertebrate and terrestrial plant species. $ Dermal contact and soil ingestion pathways for terrestrial mammals and birds were not evaluated because these routes ofexposure are not currently considered in deterministic risk assessments. Uncertainties associated with exposure pathways for terrestrial animals are discussed in greater detail in Section 1V.C. $ Risks to semiaquatic wildlife via consumption ofpesticide-contaminated fish were not evaluated. However, given that bioaccumulation ofpropazine is expected to be low, ingestion of fish by piscivorus wildlife is not likelyto be of concern. $ Risks to top-level carnivores were not evaluated dueto a lack ofdata for these receptors. Ingestion of grass, plants, fruits, insects, and seedsby terrestrial wildlife was considered; however, consumption of small mammals and birds by carnivores was not evaluated. In addition, food chain exposures for aquatic receptors (i.e., fish consumption of aquatic invertebrates and/or aquaticplants) were also not considered. However, propazine's low 

### &, suggests that it is not likelyto bioaccumulate. $ Surrogates were used to predict potential risks for species with no data (i.e., reptiles and amphibians). It was assumed that use of surrogate effects data is sufficiently conservative to apply to the broad range of species within taxonomic groups. If other species are more or less sensitive to propazine and its degradates than the surrogates, risks may be under or overestimated, respectively. $ Fate studies indicatepropazine ispersistent and mobileraising concerns about the impact on groundwater and surface water. The field dissipation studiesthat have been submitted are considered unacceptable or supplemental resulting in a significant uncertainty for this transport pathway. Additional data is needed to comprehensively ascertain the mobility ofpropazine and its degradates under field conditions. 111. ANALYSIS A. Use Characterization For this risk assessment, propazine comes in one formulation as an aqueous solution. Propazine isproposed for use as a selective herbicide in sorghum before planting or after planting but before sorghum or weeds emerge for control of annualbroadleafweeds. Application canbe made via ground sprayer or aerial broadcast for sorghum. Formulations ofpropazine that are manufactured by Griffin L.L.C. include a 98% wettable powder technical product and a 43% flowable concentrate end use product (Propazine 4L). Theproposed label for use ofPropazine 4L o sorghum isprovided in Appendix A.Figure 11-a 1. depicts areas in the US where sorghum was grown and harvested in 2003 thus providing an indication oflikely propazine use areas. Potential use areas are indicated in the Midwest states of Colorado, New Mexico, Kansas, Oklahoma, Texas and South Dakota, southern regions of Arizona and California, along the Mississippi river valley and along the eastern coastal regions ofNorth Carolina and Maryland.
In addition, the use ofpropazine on sorghum as specified on the proposed label prohibits use on sand, loamy sand, heavy clay, and high organic matter soils. As such, the risk conclusions contained in this assessment would not apply to these soil types. 

### B. Exposure Characterization Thepropazine exposure characterization in this assessment combined the environmental fate data with Tier I1 exposure models to estimate environmental exposure concentrations (EECs). Exposure models estimate EECs following the conceptual diagram ofpropazine usage and potential exposure endpoints shown in Figure 11-b2. EECs for aquatic endpoints are developed using the Tier I1 surface water models PRZMIEXAMS. These models determineEECs based on geographic areas nationwide and product use sites in closeproximity to water bodies. The input parameters used in this assessment were selected from the environmental fate data submittedby the registrant and in accordance with US EPA-OPP EFED water model parameter selection guidelines, 

### Guidance for Selecting Input Parameters in Modeling the Environmental Fate and Transport of Pesticides, Version 11, February 28,2002. A detailed aquatic resource exposure assessment is attached in Appendix C. The goal ofTier I1 aquatic modeling is to better define the range of EECs that can be reasonably expected under variable weather conditions. Likewise, EECs for birds and terrestrial mammals are estimated using the TREX 1.2.3 model and EECs for non-target plants are estimated by the TerrPlant 1.0and AgDrifi 2.0.1 models. Griffin L.L.C. is seeking registration for propazine to be used as a selective herbicide in the control of annual grasses in sorghum (grain and sweet sorghum). 1. 

### Environmental Fate and Transport Characterization a. Summary of Empirical Data Environmental fate studies reviewed suggest that propazine is moderately persistent and mobile. If applied in an outdoor environment, propazine has a high potential to leach into ground water or reach surface waters by runoff. In areas where the soils are highly permeable, the water table is shallow, and sufficient precipitation andlor irrigation occur, the use ofpropazine may result in ground water contamination. A summary of somephysical, chemical and fate properties ofpropazine isprovided in Table 111-B1.Adsorptiorddesorption
Adsorptiorddesorption

Adsorptiorddesorption
Adsorption/desorption 

### LC- ads (mLig) 83 (loamy sand); 123 (sandy loam); 158 (loam); 65(clay loam) Kd-a& 1Kd-des (mLlg) 0.67186.4 (sand,0.25%OC, 7.6 pH); 1.28111.9 (sandy loam; 1%OC, 6.8%pH); 1.30127.0 (silty clay; 1.36%OC,5.9pH); 1.3516.7 (loam; 1.71%OC,7.6pH) KO,- ads (mL1g) 268 (sand); 128 (sandy loam); 96 (silty clay); 79 (loam) 2-hydroxy-propazine &-ads Kd-des (mL1g) 1.4516.61(sandy loam); 0.2814.62 (sand); 1.3313.12(loam);4.57112.36 (silty clay) 436898-04

442873-13b. Degradation and Metabolism Table 111-B 1. Physicochemical and Fate Properties of Propazine

Existing laboratory studies indicate that propazine is stable to hydrolysis and photolysis (both aqueous and in soils). However, published literature on propazine and related chloro-s-triazines indicate that the chemical may be susceptible to hydrolysis afier adsorption onto the surface of soil colloids (a surface catalysis effect). Propazine ispersistent under laboratory aerobic soil conditions with halflives ranging fi-om 15 weeks in loamy sand soil to 41 weeks in sandy loam soil. The major soil metabolite was 2-hydroxy propazine 

### (2-hydroxy-4,6-bis(isopropy1amino)- s-triazine) and comprised a maximum of 

### 3 1%ofthe total applied radioactivity (TAR) after one year. Minor degradates consist of desethylatrazine (2-amino-4-chloro-6- 

### isopropylamino-s-triazine or DEA) (<2% ofTAR) and 2-hydroxy desethylatrazine (<5% ofTAR). No studies were submitted on the persistence of degradates (both major and minor) in the environment. Chemical structures ofthe propazine degradates are presented in Appendix 

### B. Property Adsorption/desorption

Terrestrial Field Dissipation

Propazine is not likely to volatilize from near surface soils or surfacewaters under normal environmental conditions, due to its low vapor pressure (2.9 x ton. at 20°C). Ifreleased to water, propazine is not expected to bioconcentrate in aquatic organisms, adsorb to sediment and/or suspended particulate matter, or to volatilize. This assessment assumes that propazine exhibits slow biodegradation in natural water based upon its biodegradation in soil, however, no data is available to confirm this assumption.

c. Transport and Mobility Value 

## 1 Reference (MRID)

Propazine does not adsorb as strongly to soil particles as other triazine herbicides. In most soilsused in batch equilibrium studies, especially sand and sandy loam soils, it binds weakly to soilparticles (I(oc-ads =268 and 128mL/g, respectively). Literature &c- ads (mLig) 145 (sandy loam); 329 (sand); 78 (loam); 342 (silty clay) NC (Wilson Co) 1.2 lb aiIA - bare ground sandy loam (0-6") and sandy clay loam (6-12")
t % = 7.2 days (1-21 days) t % = 58.2 days (28-184 days)
TX (Armstrong Co) 1.2 lb ai1A - bare ground loamy sand (0-6" and 6-12") T % = 52 days (186-day study) 442873-14

441848-09studies also showed that depending on soil temperature, moisture, and pH, it can become unbound (Worthing, 1983). Themajor degradate, 2-hydroxy propazine is slightly less mobile, with values ranging from 78 (loam) to 342 (silty clay) mL/g. In sand and sandy loam soils, the values are 329 and 145mLIg, respectively. Based on the information summarized above, propazine is expected to be persistent and mobile in most soils, and it isresistant to breakdown by hydrolysis, photolysis, or biodegradation. The mobility ofpropazine is also noted in the fields, where supplemental terrestrial field dissipation studies suggest that propazine dissipates slowly from the upper 6 inches (half-lives of 5 1days in TX, and 7 to 58 days in NC, <30 to 149 days in 

### NY, <3 1days in CA, and 60 to >357 days in NE) and may leach to ground water. It has also been reported in the literature that ifreleased to soil, propazine will persist longer in dry or cold conditions or other conditions which inhibit biological and chemical activity (Worthing, 1983). It is therefore very likely that in areas where soils are highly permeable, the water table is shallow, or where there is irrigation and/or high rainfall, the use ofpropazine may result in ground water contamination.
d. Field Studies The four submitted field studies were either unacceptable or considered supplemental because of inadequate sampling depths (only the upper 12 inches were sampled), lack offreezer stability data (some samples were frozen for up to 3 years), andlor the presence ofpropazine in the control and treated plots prior to the start ofthe study. Supplemental data suggest that propazine, applied as a wettable powder at 2.4 to 4.8 lb a.i./A/yr, dissipated from the upper 6 inches with a half-life of<30 to 149 days in NY, <3 1days in CA, and 60 to >357 days in NE. The degradates hydroxy-propazine, G-2873 

### [2-chloro-4,6-diamino-s-triazine], and G-30033 [2-chloro-4-amino-6- isopropylamino-s-triazine] were detected in one or more of the field studies (NY, CA, NE). Themajor laboratory soil degradate, 2-hydroxy propazine was seen in the 0-3" and 3- 6" soil layers of the terrestrial field studies at approximately 15%ofparent at day 1, and decreased to less than 5% ofparent by day 93. The other two minor degradates desethylatrazine (DEA) and 2,4-diamino-6 chloro-s-triazine (DACT), which are common to atrazine and simazine, were detected only in the 0-3" soil layer, each at less than 5% of parent at day 1,however decreasing to less than 1%by day 28. e. Review of Published Literature on the Environmental Fate ofPropazine The environmental fate ofpropazine in published scientific literature is limited and published studies vary in quality and usually contain insufficient information on procedures or raw data to adequately assess the results. However, these research findings can provide supplemental information on the environmental fate of propazine. The following discussion comes primarily fiom three published reviews 

### -Khan (1980), Montgomery (l993), and Wolfe et a1 (1990) 

### - which summarize several published studies. Propazine, like the other triazine chemicals, is weakly basic (pKa .1.85 at 22OC; Montgomery, 1993), can be easily protonated at low soil pH values, and is likely to exist as a neutral species at soil pH values more than two pH units abovethe pKa (Koshinen and Harper, 1990). Adsorption of protonated propazine is pH-dependent, with a maximum adsorption at or near the pKa (Khan, 1980). Soil organic matter plays an important role in the adsorption of propazine and other s-triazines, affecting their movement in soil (Hayes, 1970). The chemical hydrolysis of s-triazines, including propazine, is catalyzed by surface adsorption on soil colloids (Khan, 1980; Wolfe et al, 1991). Studiesby Russell et a1 (1968), Brown and White (1969), and Nearpass (1972) found evidence that the chemical hydrolysis ofpropazine was catalyzed by adsorption onto organic matter and clay. Montgomery (1993) summarized soil adsorption data fkom four studies (Burkhard and Guth, 1981;Harris, 1966; Talbert and Fletchall, 1965; Walker and Crawford, 1970)involving 3 8 soils. Thereported adsorption 

### Kd values averaged 3.4 mL/g,with a range of 0.1 to 20.5. In 35 ofthe 38 soils, the 

### Kd values were less than 

### 4.7. The

### Kc values averaged 155mL/g (ranging from 29 to 363), which are within the range ofthe 

### K,, values reported in the above mentioned environmental fate studies submitted by the registrant. Measures ofAquatic Exposure a. Aquatic Exposure Modeling Tier I1 Estimated Environmental Concentrations 

### (EEC) for propazine were estimated using EFED's aquaticmodels PRZM and EXAMS. PRZM is used to simulate pesticide transport as a result of runoff and erosion from an 10-ha agricultural field and EXAMS considers environmental fate and transport ofpesticides in surfacewater and predicts EECs in a standard pond (10,000-m2 pond, 2-m deep) with the assumption that the small field is cropped at 100%. Calculations are carried out with the linkageprogram shell - PE4VOl .pl - which incorporates the standard scenarios developed by EFED. Additional information on these models and crop scenarios can be found at: http::i\vu \v.epa.~c~r~/op13efcct 1 /models 'waterhndexhtm. Theproposed agricultural use ofpropazine for broadleaf weed control in sorghum was simulated with the sorghum crop scenarios for Texas and Kansas. The Texas and Kansas crop scenarios were chosen as they are the two states with the most harvested acreage of sorghum. Kansas ranks first in the nation for sorghum production with 220 million bushels harvested in 2004 while Texas ranks second (1 14million bushels in 2002).The maximum application rate (1.2 lb a.i./A from the proposed propazine 

### 4L label) was modeled for the Kansas and Texas sorghum scenarios. Application dates were based on the propazine label information as well as on reported planting dates stated in the USDA crop profiles for sorghum grown in Texas and Kansas. Based on the environmental fate data described above (Section II1.B.I .) and sorghum crop scenarios, EECs for aquatic exposure were estimated. Table 111-B2. contains the propazine input parameters for the PRZMIEXAMS models. Note that the Texas sorghum scenario was developed for the cumulative assessment for the organophosphate insecticides it was used in this assessment to provide spatial context to the EEC generated using the Kansas sorghum scenario. EEC's were developed for the parent propazine only (Table 111-B3.); as insufficient data exist to fully assess the persistence and mobility ofpropazine's major degradate, hydroxy-propazine 

### [2-hydroxy-4,6,bis(isopropylamino)-s-triazine] inthe environment. Furthermore, based on the risk assessment ofthe atrazine and simazine, hydroxy-propazine was not considered to be oftoxicological concern to human health. The minor degradates DEA and DACT, although ofequal potency toxicologically compared to parent propazine, were also not included in this assessment mostly due to their low detection in the laboratory soil metabolism studies and in the terrestrial field studies (less than 5% ofTotal Applied Radioactivity (TAR)). For atrazine and simazine, these chlorinated degradates were formed at much higher percentage, and ample monitoring data were available to adequately estimatetheir concentrations versus those ofthe parents. However, for propazine, minimal monitoring data exist for an adequate quantitative assessment ofthe chlorinated degradates. Additionally, asmentioned above, laboratory and field studies indicate that DEA and DACT, if formed in the environment, would not be present nor would persist at any significant concentration compared to parent propazine to adversely impact the results ofthe ecological risk assessment, as presented in this document. The proposed propazine label for sorghum stipulates buffer, or setback, distances for surface water bodies adjacent to treated fields. The label specify setback distances of 66 feet and 200 feet for propazine applications surrounding intermittent/perennial streams and lakes/reservoirs, respectively. These distances were incorporated into this assessment using AgDrifi to estimate the impact of a setback distance of 66 feet on the fraction ofdrift reaching a surface water body. Therevised spray drift percentages, which are incorporated into the PRZMIEXAMSmodeling, are 0.6% for ground applications and 6.5% for aerial applications. Models to estimate the effect of setbacks on load reduction for runoff are not currently available. It is well documented that vegetated setbacks can result in a substantial reduction in pesticide load to surface water (USDA, NRCS, 2000). It is expected that the presence of a well vegetated setback between the site ofpropazine application and receiving water bodies could result in reduction in loading. Therefore, the aquatic EECs presented in this assessment are likely to over-estimate exposure in areas with well-vegetated setbacks. While the extent ofload reductioncan not be accurately predicted through each relevant stream reach in the action area, data from USDA (USDA, 2000) suggest reductions could range from 11to 100%. b. Aquatic Exposure Monitoring and Field Data Several sources of surface water monitoring data were reviewed, including data from USGS reconnaissance studies, USGS National Water Quality Assessment Program (NAWQA) and the US EPA's Office ofWater STORET Database (1 997). TheUSGS reconnaissance post application monitoring data were performed on numerous streams within the 10 states comprising the Midwestern corn belt in 1989, 1990, 1994,and 1995. The maximum propazine contamination was detected in Ohio at 3.8 ppb. The reason for this high detection is uncertain given that Ohio is not a sorghum growing area (Figure 11-a 1) but it could possibly be associated with the only other registered use on nurseries. Although these data provide useful information, Kansas and Southern Nebraska were the only areas in the primary propazine market area covered by this USGS study. Furthermore, multiple pesticide residue studies not designed specifically for propazine may include many sampling stations outside of propazine use areas even within Kansas and Southern Nebraska. A review ofthe STORET Database (1997) reports concentrations ofpropazine residues ranging from 9.1 to 105 ppb for Kansas (detection limits of 0.5 to 1.2 ppb), and from 0.4 to 2.1 ppb for Texas (detection limit of 0.1 ppb) and 0.1 to 0.3 ppb (detection limits of 0.1 ppb) in Oklahoma. There was no detection in surface water for Colorado and New Mexico. Overall, propazine was found in 33 out of 1,097 (3% frequency of detection) surface water samples reported in these references for states located in the Midwest. A review of surface water and groundwater monitoring data collected as part ofthe USGS NAWQA program reports detects ofpropazine in water samples from several areas in the US (http://water.usgs.gov/nawqa~).NAWQA monitoring data from 1991 to 2005 indicatepropazine groundwater concentrations of 0.25 

### - 1.7ppb (5 detects out of 61 samples, or 8.2% frequency ofdetection) in Nebraska and surface water concentrations of 0.06 

### - 1.08 ppb (79 detects out of 136 samples, or 58.1% frequency ofdetection). Monitoring data from Iowa indicates no detects in groundwater (145 samples) and surfacewater concentrations of 0.06 - 0.36 ppb (25 detects out of 63 samples, or 39.7% frequency of detection). Texas surface water monitoring data shows two detects (0.06 and 0.3 1ppb) out of 25 samples (8% frequency ofdetection) while surfacewater data for the Mississippi River Embayrnent (MO, AR, MS, LA) indicates propazine concentrations of 0.06 - 0.85 ppb (22 detects in 

### 67 samples, or 32.8% frequency ofdetection). Another 65 samples from the upper Mississippi River valley and the northeast US 

### (NY, CT, DE) showed no detection ofpropazine (detection limit of 0.05 ppb). Nationally, a total of 140out of 562 surface water samples (24.9% frequency of detection) contained concentrations of propazine above the limit ofquantitation. The maximum concentration detected was 1.69ppb in Nebraska, while the averageconcentration from all detections was 0.21 ppb. Thebulk ofthe detections from this analysis were in Nebraska with fewer detections in Iowa, Missouri, and Louisiana. Although limited monitoring data were available, data were not abundant in the areas ofhigh propazine use and high run off potential, such as the coastal areas ofTexas. Furthermore, for some ofthe data the quality ofthe available monitoring data is not sufficiently reliable and at times could not be adequately or reasonably assessed due to the following problems: information about the application dose or rate, areas ofpesticide use, and farming practices involving application frequency and irrigation are insufficient or not available; the STORETmonitoring database is a collection ofisolated studies because the monitoring activities were not performed in a consistently uniform manner dueto differences in study designs that radically affected the results; characterization ofthe sampling sites such as susceptibility of the watershed soils to runoff, soil index, monthly precipitation, and residence times of surfacewater bodies is inadequate; for the STORET data the integrity ofthe sampling techniques, preservation procedures, and storagemethods are questionable or sometimes not documented; and, analytical methods and limits ofdetections are different in several monitoring studies, thus contributing to difficulty in data interpretation. Surface water monitoring results are presented here to corroborate the ability ofpropazine to contaminate surface waters and shouldbe used qualitatively only.
Table 111-B 2. PRZMIEXAMS Input Parameters for Propazine Parameter Application Rate per Event Number of Applicationsper Crop Season Aerobic Soil Metabolism t% Anaerobic Soil Metabolism t% Spray Drift Fraction Application Efficiency Value 1.2lb a.i./A

1application per year 480 days 

## '

56 days 0.006/ 0.065

0.99 10.95 Comment aerial and ground spray applicationto sorghum

estimated upper 9oth percentile
ground / aerial ground I aerial Source Propazine 4L label Propazine 4L label
MRID 44 1848-07
MRID 001 537-13 AgDrift Modeling for label specified buffers EFED Guidance, 2002

# I Table 111-B 2. PRZMJEXAMS Input Parameters for Propazine 

# I Parameter Degradation t % Anaerobic Aquatic Degradation t % Aqueous Photolysis t 95 Hydrolysis t % Value

Soil Partition Coefficient (Koc) Molecular Weight Source EFED Guidance. 2002 Comment Aerobic Aquatic

112days

## "

Stable Stable

I I EFED Guidance, 2002 960 days 

## ' ) No data; estimated (2x aerobic soil metabolism half-life) No data; estimated (2x anaerobic soil metabolism half-life) PH 7
125 mL/g4

230 glmole Water Solubility @ 20°C MRID 441 848-05 Average KO,

2.9 mg/L MRID 436898-02 MRIDs 001 529-97, 436898-04 Product Chemistry Product Chemistry



# I Table 111-B 3. Estimated Environmental Concentrations(pglL) of Propazine in Surface Water 

# I I I I Vapor Pressure

Sorghum (TX) Aerial spray 89.8 89.8 88.1 85.1 83.0 67.0 45.6 Ground spray 82.0 81.7 80.4 77.6 75.7 60.8 39.0 Simulation Scenario Sorghum (1.2 lb a.i./A)

* One in ten year value Input and output for PRZM3.12IEXAMS2.98 modeling is presented in Appendix C. 

# I

Upper 90IhPercentile based on mean half-lives of 289 and 105days. 

## '2x aerobic soil ~netabolism half-life (EFED Modeling Input Parameter Guidance, 2002). 2x anaerobic soil metabolism half-life (EFED Modeling Input Parameter Guidance, 2002). 

### 'Average ti-om all acceptable adsorptionldesorption data includingKO, values of 65, 83, 123, 158,79, 96, 128, and 268 (MRIDs 001529-97 and 436898-04 ). 2.9E-8 tom



### 3. Measures of Terrestrial Exposure 

# I Product Chemistry

Sorghum (KS) Aerial spray 53.9 53.8 53.2 52.0 51.0 44.9 35.7 Ground spray 40.8 40.7 40.2 39.5 38.8 33.9 25.8 Concentration(pg!~)*

a. Terrestrial Exposure Modeling --...---.. .~~~.--~------~-----~~--- Peak 96 hour 21-day

Terrestrial wildlife exposure estimates aretypically calculated for bird and mammals, emphasizing a dietary exposure route for uptake of pesticide active ingredients. These exposures are considered as surrogates for terrestrial-phase amphibians as well as reptiles. For exposure to terrestrial wildlife, such asbirds and small mammals, pesticide residues on food items are estimated, based on the assumption that organisms are exposed to a singlepesticide residue in a given exposure scenario. For this terrestrial exposure assessment, aerial and ground spray application methods for propazine are considered. - ----- ------------- ------------- 60-day 90-day Annual Yearly Mean AverageFor propazine spray applications, estimation ofpesticide concentrations in wildlife food items focuses on quantifying possible dietary ingestion ofresidues on vegetative matter and insects. No field residue data or field study information is available; therefore, the residue estimates arebased on a nomogram that relates food item residues to pesticide application rate. The EECs are generated from a spreadsheet-based model (T-REX Version 1.2.3) that calculates the decay of a chemical applied to foliar surfaces for single ormultiple applications. Terrestrial EECs estimated using the T-REX model are presented in Table 

### 111-B4. Theterrestrial exposure assessment isbased on the methods ofHoerger and Kenaga (1972) asmodified by Fletcher et 

### al. (1994). Terrestrial EECs for aerial and ground spray applications were derived for sorghum. Uncertainties in the terrestrial EECs are primarily associated with a lack ofdata on interception and subsequent dissipation fi-om foliar surfaces. When data are absent, as in this case, EFED assumes a 35-day foliar dissipation half life, based on the work ofWillis and McDowell(1987). For propazine, EFED assumed a default half life of 35 days. The EECs on food items may be compared directly with dietary toxicity data or converted to an oral dose, as is the case for small mammals. The risk assessment for propazine uses upper bound (i.e., 

### 9oth percentile) and mean predicted residues as the measure of exposure on selected avian or mammalian food items immediately following propazine application (at the maximum label rate) for sorghum. For mammals, the residue concentration is converted to daily oral dosebased on the fraction ofbody weight consumed daily as estimated through mammalian allometric relationships.

Effects on non-target terrestrial plants are most likely to occur as a result of spray drift andlor runoff fi-omaerial and ground applications ofthe liquid formulation. Spraydrift and runoff is an important factor in characterizing the risk ofpropazine to non-target plants, which is assumed to reach off-site areas. The TerrPlant model (Ver. 1

### .O) predicts EECs for terrestrial plants located in dry and semi-aquatic areas adjacent to the treated field. The EECs arebased on the application rate and solubility ofthe pesticide in water and drift characteristics, which depend on ground or aerial applications. The amount of propazine that runs offis a proportion ofthe application rate and is assumed to be 1% based onpropazine's solubility of <10 ppm in water. Drift from ground and aerial applications are assumed to be 1% and 5%, respectively, ofthe application rate. For dry areas, the loading ofpesticide active ingredient from runoff to an adjacent non-target area is assumed to occur from one acre oftreatment to one acre ofnon-target area and is characterized as "sheet runoff '. For terrestrial plants inhabiting semi-aquatic (wetland) Table 111-B 4. Terrestrial Bird and Mammal EEC's (Residues) Following Application of Propazine to Sorghum Terrestrial Use Sorghum Application. Rate (Ibs a.i./A) 1.2 Food Items Short Grass Tall Grass Sm. Insects, Broadleaf Plants Lg. Insects, Fruits, Pods Maximum EEC (mg/L)

288 132 162 18 Mean EEC (mg/L)

102 43 54 8 

# -areas, runoff is considered to occur from a larger source area with active ingredient loading originating from 

### 10 acres 

### oftreated area to a single acre ofnon-target wetland and is characterized as "channelized runoff". Predicted terrestrial plant EECs following ground and aerial spray applications ofpropazine to sorghum are summarized in Table 111-B5.

I I I I I 

## ' EEC = Sheet Runoff + Drift (I % for ground; 5% for aerial) 

## 'EEC = Channelized Runof+Drift (1% for ground; 5% for aerial) 

### 'EEC for ground (appl. rate x 1%drift); for aerial (appl. rate x 5% drift) Table 111-B 5. EECs for Terrestrial Plants Located Adjacent to Propazine Treated Sorghum Fields

C. Ecological Effects Characterization

Terrestrial Use
Sorghum (1.2 lbs a.i.1A)

1. Aquatic Effects Characterization Table 111-C1presents the toxicity endpoint values from the studies used to calculate RQs and estimaterisk to aquatic receptors from exposure to propazine through surface runofflleaching. Details ofthe registrant-submitted studies for aquatic animals and plants are provided below and in Appendix 

### F. Application

Method

Aerial Ground Concentration (lbs a.i./A)

Table 111-C 1. Propazine Toxicity Endpoint Values for Assessing Risk to Aquatic Organisms Total Loading to Areas Adjacent to Treated 

### rea as' 0.067 0.024

Exposure Scenario Total Loading to SemiAquatic Areas Adjacent to Treated

### re as' 0.132 0.132

Species Drift to Adjacent ~reasj
0.06 0.012

Freshwater Fish Exposure Duration

Acute Chronic Toxicity Endpoint Value

No valid studies available Fathead minnow Pirnephales promelas Freshwater Invertebrates Endpoint

Acute

Chronic Reference (Classification)

Early life

stage

Water flea Daphnia magnn Water flea Daplznia magnu NOAEL = 0.72 mg ai/L

EstuarineIMarine Fish 48 hours

2 1days

Acute Chronic Reduction in length MRID 442873-07 (Supplemental)

ECso= >5.32 ppm ai NOAEC = 5.32 ppm ai NOAEC =0.047 ppm ai LOAEC =0.09 1ppm ai

EstuarineIMarine Invertebrates No data submitted

Sheepshead minnow Cyprinodon variegatus Lethality

Growth MRID 442873-05 (Awaiting final EFEDreview) MRID 443276-02 (Core)

36-day NOAEC = 1.34 mg ai/L LOAEC = 2.59 mg ailL Embryo survival; hatching success MRID 44 1848-02 (Awaiting final EFED)a. Aquatic Animals Table 111-C 1. Propazine Toxicity Endpoint Values for Assessing Risk to Aquatic Organisms

(I) Freshwater Fish and Invertebrates, Acute Exposure Scenario Acute Chronic

Fish toxicity studies for two freshwater speciesusing the TGAI arerequired to establish the acutetoxicity of propazine to fish. Thepreferred test species are rainbow trout (a coldwater fish) and bluegill sunfish (a warmwater fish). No valid acute freshwater fish studies are available for either the parent propazine or the degradates.
A freshwater aquatic invertebrate toxicity test using theTGAI is required to establish the toxicity ofpropazine to aquatic invertebrates (Table 111-C2). Thepreferred test speciesisDaphnia magna. A submitted acute study for daphnids provided a 48-hr ECSo value of>5.32 pprn ai (NOAEC 5.32pprn ai) for the TGAI. This value will be used to assess acuterisk of propazine to freshwater invertebrates (MRID 442873-05). The classification ofthis study is currently being reevaluated in order to determine if daphnids were exposed to propazine at the limit of solubility. In addition, no toxicity data are available to assess the acute risk ofthe degradates to freshwater invertebrate species.Species
Saltwatermysid Mysidiopsis bahia

Saltwater mysid Mysidiopsis bahia Aquatic Plants

(2) Freshwater Fish and Invertebrates, Chronic Exposure Duration 96 hours 28-day

Nonvascular Macrophytes

Table 111-C 2. Freshwater Invertebrate Acute Toxicity for Propazine

For freshwater fish chronic studies (early life-stage or a full life-cycle test) the preferred species is the fathead minnow. In an early life-stage study, propazine induced a significant reduction in length with a NOAEL of0.72 mg ai/L (Table IIIC3.). This value will be used to assess the chronic risk ofpropazine to freshwater fish (MRID 442873-07). The studywas classified as supplemental because 

### pH and Species Waterflea (Daphnia magna) Toxicity Endpoint Value

=4.20 ppm ai NOAEC = 0.586 ppm ai NOAEC = 0.269 ppm ai LOAEC = 0.706 ppm ai

Diatom Naviculapelliculosa Duckweed Lemna gibba

% ai 98.0 Endpoint Lethality Growth; Reproduction
120 days 120 days Reference (Classification) MRID 44 1848-0 1 (Acceptable) MRID 441848-03

(Supplemental)

48-hour EC50 (PP~ ai) >5.32 ECso= 0.0248ppm ai NOAEC = 0.0065 ppm ai EC50= 0.10 ppm ai NOAEC = 0.022 ppm ai Cell density Frond density

Study Classification Awaiting final EFED review Toxicity Category

moderately toxic MRID 442873- 10 (Core) MRID 442873-09 (Core)

MRID No. Author, Year

442873-05 Murrell, 1994hardness exceeded recommended levels, potentially affecting solubility. No toxicity data are available to assess the chronic risk ofthe degradates to freshwater fish species.

For life-cycle studieson freshwater invertebrates, thepreferred test speciesis Daphnia magna. Submitted data show reductions in growth (length and weight) in daphnids following exposure to propazine. The

### NOAEC of 0.047 ppm ai will beused to assess chronic risk ofpropazine to freshwater invertebrates (MRID 443276-02). No toxicity data are available to assess the chronic risk of the degradates to freshwater invertebrate species. Table 111-C3. Freshwater Fish Chronic Toxicity for Propazine

Acute and chronic toxicity testing with estuarinelmarine fish and invertebrates using the TGAI is required for propazine because the end-useproduct is expected to reach the marinelestuarine environment. Propazine is expected to beused in coastal county locations where sorghum may be grown (i.e. Texas, North Carolina, Maryland and Louisiana (Figure 11-a 1)). Species

Table 111-C 4. Freshwater Invertebrate Chronic Toxicity for Propazine

(3) Estuarine/Marine 

### Fish and Invertebrates, Acute Early Life Stage Study under Flow-through Conditions
Fathead minnow 98.0 0.7211.14 Growth 442873-07 Supplemental (Pimephales promelas) Rhodes, 1995 MRID No. Author, Year

For acute toxicity testing with estuarinelrnarinefish, the preferred test species is sheepshead minnow. No toxicity studies were submitted by the registrant to assess the acuterisk ofpropazine or its degradates to estuarinelmarine fish species. Study Classification

Study Classification Core Species
Waterflea (Daphniamagna)

For acute toxicity testing with estuarinelmarine invertebrates, the preferred species are the mysid shrimp and eastern oyster. Propazine is categorized as moderately toxic to the mysid shrimp, based on mortality and sublethal effects (LCso=4.20 ppm ai). Propazine is categorized as practically non-toxic to the eastern oyster at the limit of solubility with an ECS0 >3.72 mg ai1L (MRIDs 441848-01 and 442873-06). The oyster study was originally classified as supplemental; however, 

### EFED reevaluated Endpoints Affected % ai NOAELLOAEL (mg ailL)

% a.i.
98.0 21-day NOAECILOAE C (ppm ai) 0.04710.091 Endpoints Affected Growth MRID Author, Year 443276-02 Murrell & Veltri, 1997the data and established these effect levels (Table 111-C5). No toxicity data are availableto assess the acute risk ofthe degradates to estuarinelmarine invertebrate species. The 

### LC5() =4.20 ppm in the mysid study will be used to assess acuterisk to marinelestuarine invertebrates.

(4) Estuarine/Marine Fish and Invertebrates, Chronic Table 111-C 5. EstuarineIMarine Invertebrate Acute Toxicity for Propazine

For the chronic toxicity testing with estuarinelmarine fish the preferred test species is sheepshead minnow. In an early life-stage study, propazine affected embryo survival and hatching success at 2.59 mg ai1L (Table 111-C6). The NOAEC of 1.34mg ai/L will be used to assess the chronic risk ofpropazine to estuarinelrnarine fish (MRID 441 848-02). This studywas originally classified as supplemental; however, EFED reevaluated the data and established these effect levels. No toxicity data are available to assess the chronic risk from the degradates to estuarinelmarine fish species. Species Eastern oyster (Cmssostrecr virginica) Mysid (Mysidopsis bnhin)

For the life-cycle toxicity study with estuarine/marine invertebrates, thepreferred test species is mysid shrimp. The data submitted indicate that propazine produced significant effects to growth and reproduction at 0.706 ppm ai. TheNOAEC of 0.269 ppm ai will be used to assess the chronic risk ofpropazine to estuarine/marine invertebrates (MRID 441 848-03); the study was classified as supplemental due to deviations in study design. No toxicity data are available to assess the chronic risk of the degradates to estuarine/marine invertebrate species. % a.i. 98.0

98.0

Table 111-C 6. EstuarineIMarine Fish Chronic Toxicity for Propazine Species 96-hour EC5dLCso 13.72mg ai/L

4.20 ppm ai

% ai Toxicity Category practically nontoxic moderatelytoxic

Early Life Stage Study under Flow-through Conditions NOAECILOAEC (mg ailL)
Sheepshead minnow (Cyprinodon vnriegatus) MRID Author, Year

442873-06 Boeri et al., 1995
44 1848-01 Boeri et al., 1995 Study Classification Awaiting final EFED review

Acceptable

Endpoints Affected

98.0 MRID No. Author, Year

1.3412.59 Study Classification

Growth 44 1848-02 Boeri et al., 1995 Awaiting EFED validationb. Aquatic Plants Several aquaticplant toxicity studies using the TGAI arerequired to establish the toxicity ofpropazine to non-target aquatic plants. Therecommendation is for testing of five species: freshwater green alga (Selenastrum capricornutum), duckweed (Lemna gibba), marine diatom (Skeletonema costaturn), blue-green algae (Anabaena flos-aquae), and a freshwater diatom (Naviculapelliculosa). In a Tier I1 toxicity test, the 14-dayEC50for the freshwater vascular plant (duckweed) is 0.10ppm ai (NOAEC =0.022 ppm ai), based on frond density; and the lowest 7-day ECS0 for the freshwater non-vascular plant (diatom) is 0.0248 ppm ai (NOAEC =0.0065 ppm ai), based on cell density. These values will be used to assess the risk ofpropazine to aquaticvascular and nonvascular plants (Table 111-C8).

TheTier I1 results for propazine degradates indicate that the most sensitive algae of the five species is generally the blue-green algaAnabaena inaequalis with ECso values ranging from 100to > 100,000 ppb. All studies were classified as supplemental because NOAEC and raw data were unavailable.

### a. TerrestrialAnimals 

### (I) Birds, Acute and Subacute An oral toxicity studyusing the technical grade ofthe active ingredient (TGAI) is required to establish the acute toxicity ofpropazine to birds. Thepreferred guideline test species 

### is either mallard duck (a waterfowl) or bobwhite quail (an upland gamebird). The submitted acute data indicate that propazine is at most slightly toxic to upland gamebirds with an acute oral LDsovalue of>1,640 mg aikg(Table IIIC 11). TheNOAEL was determined to be 244 mg ailkg, based on weight loss (MRID 442873-01).The results ofthe acute avian oral LDS0 study with DEA show that it is slightlytoxic. Ten, forty, ninety, and one-hundred percent mortality was observed in quail exposed to DEA at 445,735, 1212, and 2000 mag-bwby 14 days (MRID # 465000-09). In addition, sublethal treatment-related effects, including reductions in body weight gain and food consumption, were observed at 270 mag-bw(lowest dose tested) and above.

Two dietary studiesusing the TGAI are required to establish the subacute toxicity of propazine to birds. The preferred test species are mallard duck and bobwhite quail (Table 111-C13.). The data that were submitted show that the 8-day acute dietary LCSO's were >4,930 ppm and >5,140 for bobwhite quail and mallard, respectively; therefore, propazine is at most, categorized as slightly toxic to upland game birds on a subacute dietarybasis (MRIDs 442873-02 and MRID 442873-03).

(2) Birds, Clzronic Avian reproduction studies using the TGAI are usually required for pesticide registration because birds may be subject to repeated or continuous exposureto the pesticide, especially preceding or during thebreeding season. Thepreferred testspecies aremallard duck and bobwhite quail. No avian reproduction studies were submitted by theregistrant. (3) Mammals,Acute Wild mammal testing is required on a case-by-case basis, depending on the results of lower tier laboratory mammalian studies, intended use pattern and pertinent environmental fate characteristics. In most cases, rat or mouse toxicity values obtained from the Agency's Health Effects Division (HED) substitutefor wild mammal testing. These toxicity values are reported below (Tables 111-C14and 111- C15). The results indicate that propazine is categorized aspractically non-toxic (Toxicity Category IV) to small mammals on an acute oral basis (LD50value >5,050 mg/kg; MRID 43474 1-01).

The acutemammalian oral toxicity study with the degradate deethylatrazine(DEA) provides LDS0 values between 668 and 1881mag,indicating that it is slightly toxic when administered via the oral route (Table 111-C15).

(4) Mammals, 

### Developmental/Reproductive Table 111-C 15. Mammalian Acute Toxicity for the Degradate Deethylatrazine

In developmental toxicity studies, administration ofpropazine by gavageproduced maternal toxicity in both Sprague-Dawley rats and New Zealand rabbits with a NOAEL of 10mg/kg bwlday (Table 111-Cl6). Decreased ossification was also observed in offspring ofrats, resulting in a developmental NOAEL of 10mg/kg/day. No treatment-related effects in developmental parameters were observed in rabbits. Salivation was also observed in rats at doses 2500 mg/kg/day (MRIDs 001502-42 and 441 534-01). Species

In a 3-generation reproduction study with rats exposed to propazine, no treatmentrelated effects on reproduction were observed; consequently, the NOAEL for reproductive toxicity was 250 mg/kg bwlday. Based on decreased body weights in males and females, the parentalloffspring NOAEL was 5 mg/kg/day. This value will be used to assess the chronic risk of propazine to mammals (MRID 000414-09). Laboratory rat 98.0 668 mglkg LD5o 430132-02 Core (Rattusnonlegicus) 1,881 mglkg (mortality) Kuhn, 1991 % ai Toxicity Value Affected Endpoints MRID No. Author, Year Study ClassificationI Maternal toxicity - Decreased body weight and food consumption; salivation was also observed. Developlnental toxicity - Decreased ossification. 

## 'Maternal toxicity - Decreased body weight gain and food consu~nption Developlnental toxicity - No treatment-related effects were observed. %arental/offspring toxicity - Decreased body weights in males and females Reproductive toxicity - No treatment-related effects were observed. In subchronic studies with the degradates, it appears that deethylatrazine (DEA) and diaminochlorotriazine (DACT) also produced decreased body weights in rats at doses as low as 25 ppm ai and 250 ppm ai, respectively (Table 111-C17). DEA and DACT also resulted in developmental effects in rats at 100ppm ai (fused sternebrae 

### and poor ossification) and 500 ppm ai (embryo resorption and poor ossification), respectively.
Table 111-C 17. Mammalian Subchronic and Reproduction Toxicity for the Propazine Degradates Species Laboratory rat 98.2 NOAEL < 100 red. LH and prolactin 415109-01 Supplemental (Rattus DACT LOAEL 100 levels Hazleton nowegicus) (G-28273) Lab., 1990 Fed for 14 200 red. estrogen, LH, days prolactin and progesterone Laboratory rat 95.7 NOAEL 50 red. in female body weight 430132-06 Acceptable- (Rattus DEA LOAEL 500 red. in food efficiency for Ciba- Guideline nowegicus) (G-30033) male and female rats Geig~, 13-week diet 1991
Laboratory rat 98.2 NOAEL 10 Estrous cycle effects in 430132-07 Core-Guideline (Rattus DACT LOAEL 100 female rats Cibanor-vegicus) (G-28273) Geig~, 13-week diet NOAEL 100 red. body weight gain in 1991 LOAEL 250 males and female Week 12
Dog - 95.7 NOAEL 100 red. body weight & weight 430132-04 CoreBeagle DEA LOAEL 1,000 gain in males and females; Ciba- Minimum LOAEL Endpoints % ai MRID No. Year (PP~ ai) Study ~lassification(5) 

### Insects, Acute Contact Table 111-C 17. Mammalian Subchronic and Reproduction Toxicity for the Propazine Degradates

-

In an acute contact studywith the honey bee, propazine was determined to be relatively non-toxic. At 96 hours, mortality was 2.47% at a dose of 96.69 pglbee (Atkins et al. 1975). The study was scientifically sound and showed that propazine is relatively non-toxic to honeybees. Species



### (6) 

### Insects, Residual Contact
No residual contact toxicity studywas submittedby the registrant. (Canis sp.) (G-30033) red. heart tobrain weight; Geigy, 13-week normocytic/nonnochromic 1992 Feeding anemia, paroxysmal atrial fibrillation and right atrial wall hemorrhagic inflammation with angiomatous hyperplasia
Dog -Beagle 98.7 NOAEL 5 1of 8 females had tremors 4 13924-01 Minimum (Canis sp.) DACT LOAEL 100 Ciba1 -Year (G-28273) Geig~, Feeding 1990 Laboratory rat 95.7 NOAEC 5 red. body weight; weight 430132-09 Acceptable- (Rattus DEA LOAEC 25 gain and food consump. Ciba- Guideline nowegicus) (G-30033) Development: Geigy, Dosed on NOAEL 25 Fused stemebrae 1 & 2 1992 Days 6-15 LOAEC 100 Poor ossification of digit 5
Laboratory rat 98.2 NOAEL 500 red. body weight gain and 4 13924-02 Minimum (Rattus DACT LOAEL 3000 food consumption Cibanonegicus) (G-28273) Geigy, Dosed on Development: 1989 Days 6- 15 NOAEL 50 incr. resorption of embryos LOAEC 500 incr. unossified bones % ai

b. Terrestrial Plants Tier I1 terrestrial plant toxicity studies were conducted to establish the toxicity of propazine to non-target terrestrial plants (MRID 441 848-04). This studywas reevaluated in 2006 and additional statistical analyses were performed. Classification ofthe study is awaiting final EFED review. (PPm ai) LOAEL Endpoints MRID No. Year Study ClassificationResults ofTier I1 toxicity studies with monocots and dicots indicate that seedling emergence and vegetative vigor are severely impacted by exposure to propazine. Seedlingemergence, based on shoot weight, was adversely impacted in monocots (onion) at an EC25of 0.035 lb ai/A and in dicots (lettuce) with an EC25of0.016 lb ai/A (Table 111-C18). Vegetative vigor in monocots, based on shoot weight, was adversely impacted 

### in monocots (wheat) at an EC25of0.046 lb ai/A and in dicots (cucumber) at an EC25 of 0.10 lb ai/A. The observed effects to monocots and dicots included stunting, chlorosis, necrosis, and plant death. These values will beused to assess the risk ofpropazine to non-target terrestrial plant species. 

### TerrestrialField Studies Terrestrial field studies were not submitted.Table 111-C 18. Terrestrial Non-Target Plant T~xicity.~ Species 

# I Seedling Emergence 

# I Vegetative Vigor

Monocots Corn Oat Onion Ryegrass Wheat Dicots Cabbage Cucumber Lettuce Radish Soybean Tomato



# - 'MRID 4418r Shoot weight ECzs NOAEC (Ib ai/A) (lb ai/A)

>2.4 2.4 0.050 <0.010 0.035 <0.010 0.83 0.077 0.14 0.010

0.098 <0.011 0.12 0.077 0.016 0.0047 0.16 0.077 0.97 0.59 0.18 <0.077 1-04, Study authorsD. Schwabet a1 Shoot length EC25 NOAEC (lb aVA) (lb aiIA) O/O Emergence EC2s NOAEC (lb ai/A) (lb ai1A) Shoot weight EC25 NOAEC Shoot length ECzs NOAEC (lb ai/A) (lb ai/A)

### IV. 

### RISK CHARACTERIZATION A. Risk Estimation 

### - Integration of Exposure andEffects Data Risk characterization integrates EECs and toxicity estimates and evaluates the likelihood of adverse ecological effects to non-target species. In a deterministic approach, an exposure estimate is divided by a single point estimate of toxicity (Table IV-A1) to calculate a risk quotient (RQ). The RQ is then compared to the Agency's levels of concern (LOCs) that serve as criteria for categorizing potential risk to non-target organisms (Appendix 

### G).
Table IV-A1.

Taxonomic

Group

Birds

Mammals

Terrestrial Invertebrates

Terrestrial Plants

Freshwater Fish

Freshwater Invertebrates

Estuarineimarine Fish

Estuarinelmarine Invertebrates
Aquatic Plants Toxicity reference
Assessment

Endpoint

Survival Sublethal effects Reproduction, Growth
Survival Reproduction, Growth Survival

Survival, Growth

Survival

. Reproduction,

Growth Survival Reproduction, Growth Survival

. Reproduction,

Growth Survival 

### - Reproduction,

Growth Survival, Growth values used to calculaterisk quotients for propazine

Measure of Effect
Bobwhite quail LDS0 =>I 640 mg aiikg bw; NOAEL= 244 mg ailkg bw. LCSo =>4930 ppm ai; NOAEL not detennined. (MRID 442873-01)
No data submitted

Rat LDjo=>5050 mglkgiday (MRID 434741-01)
Rat NOAEL = 5 mgikglday, LOAEL = 50 mglkglday (MRID 00041 4-09) Honey bee: 96 hours: 2.5% mortality at 96.7 pghee Seedling emergence onion ECzj = 0.035 Ib ai/A; NOAEC <0.010 Ib ai/A Seedling emergence lettuce EC2, = 0.016 Ib ai1A; NOAEC <0.0047 Ib ai/A Vegetative vigor wheat ECzj=0.046 Ib ailA; NOAEC <0.020 Ib ailA Vegetative vigor cucumber EC2, =0.10 Ib ai1A; NOAEC <0.075 Ib ailA (MRID441848-04) No valid studies available

Fathead minnow NOAEC =0.72 mg ailL (MRID 442873-07)
Water flea ECjo= >5.32 ppm ai; NOAEC = 5.32 ppm ai (MRID442873-05)

Water flea NOAEC = 0.047 ppm ai; LOAEC =0.091 ppm ai (MRID443276-02) No data submitted Sheepshead minnow NOAEC = 1.34mg ailL; LOAEC = 2.59 mg ailL (MRID 44 1848-02) Saltwater mysid LCjo=4.20 ppm ai; NOAEC = 0.586ppm ai (MRID441848-01) Saltwater rnysid NOAEC = 0.269 ppm ai; LOAEC = 0.706 ppm ai (MRID441848- 03) Diatom ECjo= 0.0248 ppm ai; NOAEC = 0.0065 ppm ai (MRID 442873-10). Duckweed ECS0 = 0.I0 ppm ai; NOAEC = 0.022 ppm ai (MRID 442873-09).1. Non-target Aquatic Animals and Plants

a. Fish and Invertebrates Acute 

### Risks A comparison of estimated peak propazine concentrations in surface water following application to sorghum to the acute toxicity values (LC50/EC50~) for freshwater and marinelestuarine invertebrates is provided in Table IV-A2. Acute risk quotients were not calculated for freshwater or estuarinelrnarine fish due to the lack of acute toxicity information. Acute risk quotients (RQs) for estuarinelmarine invertebrates are less than the Level ofConcern (LOC), indicating adverse effects arenot expected. Acute risk quotients for freshwater invertebrates were not calculatedbecause the acute ECS0 value for freshwater invertebrates is greater than the highest concentration tested. A qualitative discussion ofthe risk to freshwater invertebrates based onthis study will be provided in the Risk Description section.
Table IV-A2. Summarized Acute Risks for Aquatic Organisms a'b Scenario Freshwater Freshwater EstuarineiMarine EstuarineIMarine (1.2 lbs a.i./A) Peak EEC (ppb) Fish Invertebrate Fish 

### invertebrated JSorghumin Kansas 

### I

erial App. 53.9 NAc Not estimated NA 0.01 40.8 Not estimated <0.01 erial App. 89.8 NA Not estimated NA 0.02 I~round App 82.0 Not estimated 0.02 

# I " Detailed calculations of PRZM 3.121EXAMS 2.98modeling areprovided in Appendix C. -. .- Acute toxicity threshold (LCSo) was 4.2 ppln for estuarineln~arine invertebrates. 'There are no valid acute toxicity studies for freshwater and estuarinelmarine fish; thus, RQ's were not calculated. RQs were not calculated for freshwater invertebrates because the ECsois greater than the highest concentration tested.

Acute aquatic LOCs: acute endangered species 0.05,acuterestricted use 0.1, acute non-listed species 0.5 

### ChronicRisks The aquatic chronic LOC of 1 is exceeded for freshwater invertebrates based on the 2 1-day average EEC for the sorghum crop scenarios in Kansas and Texas. All other chronic RQs for freshwater and estuarinelrnarine fish as well as estuarinelrnarine invertebrates arebelow the chronic LOC of 

### 1 (Table IV-A3). Chronic risk to aquatic invertebrates is discussed further in the Risk Description section.

### b. Aquatic Plants Table IV-A3. Summarized Chronic Risks for Aquatic Organisms

For propazine, there are exceedances ofthe LOC for listed vascular and non-vascular aquatic plants exposed to runoff7drift fiom ground and aerial spray applicationsto sorghum (Table IV-A4). There are no exceedances of the LOC for unlisted vascular aquatic plants for the Kansas and Texas scenarios; however, there are exceedances of the LOC for unlisted non-vascular aquatic plants. Risk to aquatic plants will be discussed further in the Risk Description section. Scenario (1.2 lbs a.i.1A) Sorghum in Kansas Aerial App. Ground App. Sorghum in Texas Aerial App. Ground App.

a Detailed calculations of PRZM 3.121EXAMS 2.98modeling areprovided in Appendix C.

Chronic toxicity thresholds were NOAEC of 0.72 ppm for freshwater fish and NOAEC of 0.047 ppm for freshwater invertebrate. Estuarinel~narine fish NOEAC was 1.34ppm and invertebrate NOAEC was 0.269 ppm. RQ calculation based on 60-day EEC for fish and 21-day EEC for invertebrates. *RQ exceeds the chronic risk LOC of 1.0 2 1/60Day EECs (ppb)

53.2152.0 40.2139.5 88.1i85.1 80.4177.6

Table IV-A4. Summarized Acute Aquatic Plant Risk Quotients a.b.c.d



### .. b* RQ exceeds the Endangered Species LOC; RQ 

### ; I.o. '** RQ exceeds the aquatic plant risk LOC; RQ > 1.O.

The endangered toxicity threshold (NOAEC) was 0.022 ppm for vascular plants and 0.0065 for non-vascular plants; acute toxicity thresholds (ECSo) were 0.10ppm (MRID 442873-09) and 0.0248 ppm ( 442873-10) for vascular and freshwater nonvascular plants, respectively. Ground App. 

## I 82.0

2. Non-target TerrestrialAnimals a. Birds Freshwater Fish
0.07 0.05 0.12 0.1 1

Non-endangered Vascular Non-vascular
0.54 2.17** 0.4 1 1.65** 0.90 3.62"" Scenario (1.2 Ibs a.i./A)

Acute 

### Risks Acute avian RQs were not calculated with either the oral gavage study or the subacute dietary study with bobwhite quail because the LD/LC50values are greater than the highest dose/concentration tested. A qualitative discussion ofthe acuterisk to birds, reptiles, and terrestrial-phase amphibians will be provided in the risk description. "Detailed calculations of PRZMIEXAMS modeling is vrovided in Avvendix C. 3.72* Freshwater Invertebrate
1.13* 0.86 1.87* 1.71*

Peak EEC (PP~)

12.62* EstuarineiMarine Fish
0.04 0.03 0.06 0.06

Endangered

vascular Sorghum in Kansas Aerial App. Ground App. Sorghum in Texas Aerial App. 0.82 3.31** EstuarinelMarine Invertebrate
0.20 0.15 0.33 0.30

Endangered Non-vascular

2.45" 1.85* 4.08* 53.9 40.8 89.8 8.29" 6.28* 13.82"Chronic Risks Chronic risks tobirds were not assessed due to the lack of avian chronic toxicity studies. b. Mammals Acute Risks The acute RQs for mammals were not calculated because the LDso value obtained from the acute oral study is greater than the highest dosetested. A qualitative discussion of acute risk to mammals will be provided in the risk description. ChronicRisks To evaluatethe chronic risk to mammals, RQs were calculated using the rat reproductive NOAEL of 5 mg/kg bw and NOAEC of 100ppm. The RQs are detailed in Table IV-A5 and are summarized in Appendix D. Assuming maximum and mean residue levels at the maximum single application rate (1.2 lbs a.i./A for sorghum), the chronic dose-based risk quotients exceed the chronic LOC for mammals for the 15g, 35 g, and 1000gmammal weight classes consuming short grass, tall grass and broadleaf foragelsmall insects. The 15gand 35gmammal RQs exceed the chronic LOC when consuming the maximum predicted propazine residue on fruitllarge insects. The chronic LOC for all weight classes ofmammals consuming seedslpods was not exceeded. At the maximum residue levels, the chronic dietary-based RQs exceed the chronic LOC for all food categories except fruit, large insects, seeds and pods. The chronic dietary-based RQ exceeds the chronic LOC for mammals consuming short grass using mean residues levels. Chronic risk to mammals is discussed further in the Risk Description section.
Table IV-AS. Mammalian Chronic Risk Quotient Summary Food type
Short grass
Tall grass
- Broadleaf forage, small insects Fruit, large insects Weight class (g)
15 3 5 1000

15 35

Seeds, pods 1000 15 35 1000

15 35 1000

15 RQs for 1.2Ibs a.i./A

21.34" 11.44" 11.45* 9.78"

aChronicreproductive toxicity NOAEL = 5 mglkg bwlday; NOAEC = 100ppm.

Detailed calculations of the T-REX model (Ver. 1.2.3)and Chronic RQs areprovided in Appendix D. * RQ exceeds the Chronic Risk LOC; RQ > 1.O. 3 5 1000 Predicted maximum residues Dose-Based RQs 

## I Dietary-Based RQs 24.99*

5.24* 14.06* 12.01* 6.44" 1.56* 1.33* 0.72 0.35 Predicted mean residues Dose-Based RQs 

## IDietary-Based RQs 8-82" 2.88*

1.32*

0.30 0.16 1.62*

0.18 0.14 0.07 7.57* 3.98* 3.73" 3.21* 1.02*

0.43 1.68* 4.67* 4.01" 2.11" 0.73 0.62 0.33 0.16 0.54

0.08c. 

### Non-Target Terrestrial-phaseAmphibians, Reptiles and Beneficial Invertebrates
EFED currently uses surrogate data (birds) for terrestrial non-target amphibians and reptiles and does not quantify risks to terrestrial non-target insects. Risks are qualitatively discussed in the Risk Description section ofthis document. 3. 

### Non-target Terrestrial Plants in Terrestrial and Semi-aquatic Environments Table IV-A6 presents terrestrial plant RQs based on propazine use on sorghum for both ground and aerial spray applications. For the terrestrial use ofpropazine and the maximum application rate of 1.2lbs a.i./A from aerial spray application, the acute LOC is

- - - . -- exceeded for nonendangered monocots and dicots located in adjacent areas and in semiaquatic areas primarily as the result of runoff; and for nonendangered monocots as a result of spray drift (Table IV-A6). Likewise,the acute LOC is exceeded for monocots in semi-aquatic areas and dicots in adjacent and semi-aquatic areas primarily as the result of runoff from ground spray applications. RQs are higher for aerial-applications when compared to ground applications. This would be expected given the percentages ofdrift assumptions of 5% and 1% for aerial and ground sprays, respectively. For both ground and aerial spray application, the LOC is exceeded for endangered monocots and dicots located in adjacent and semi-aquatic areas (Table IV-A6). The LOC for endangered species is exceeded for monocots and dicots in dry areas exposed to spray drift from both ground and aerial applications. 

# I Table lV-A6. Terrestrial Plant Risk Quotient Summary for Terrestrial Spray Use on Sorghum a'b'c'd 

# I

-

. - -- . . -.- . -.. -. .. - - .

. .- . . Monocot 

## I 0.69 

## I 3.77** 

## I 0.34 

## I >2.40* 

## 1 >13.20* 

## 1 >1.20*

Dicot 

### I 1.SO** 8.25** 0.75 5.11* I 28.09* I 2.55 Scenario

Sorghum (1.2 lbs a.i./A) Aerial spray application Monocot 

## I 2.06** 

## I 5.14** 

## I 1.71** 

## I 6.72" 

## I 13.20* 

## I 6.00*

Dicot 

## I 4.50** 

## 1 11.25** 

## 1 3.75** 14.30" 28.09* 12.77*

a Detailed calculations for RQs and TerrPlant Ver. I .O input and output are provided in Appendix E.

Non-endangered toxicity thresholds (EC25) were 0.035,0.016,0.046, and 0.10 Ib a.i./A for seedling emergence monocot, seedling emergence dicot, vegetative vigor monocot, and vegetative vigor dicot, respectively. 'Endangered toxicity thresholds (NOAEC) were <0.01, 0.0047,0.02, and c0.075 Ib a.i./A for seedling emergence monocot, seedling emergence dicot, vegetative vigor monocot, and vegetative vigor dicot, respectively. d* RQ exceeds the Endangered Species LOC; RQ >I .O.

** RQ exceeds the Acute Risk LOC; RQ >I .O. Sorehum (1.2 lbs a.i./A) Endangered RQs Terrestrial Semi-aquatic Adjacent area

# I Adjacent area

# I Drift Non-endangered RQs Terrestrial Adjacent area Semi-aquatic Adjacent area Drift

### B. Risk Description Therisk hypothesis states that the use of propazine for weed control in sorghum has the potential to compromise survivorship, reproduction, andlor growth ofnon-target aquatic and terrestrial animals and plants, including Federally-listed endangered and threatened species. Based onthe available ecotoxicity data and predicted environmental exposures, this ecological risk assessment supports the presumption of chronic risk to freshwater invertebrates and mammals and risk to non-vascular unlisted aquaticplants and to non-target terrestrial monocots and dicots following aerial and ground applications. This ecological risk assessment also supports the presumption of acute endangered species risk to vascular aquatic plants and non-target terrestrial monocots and dicots. Thepresumption of acute risk to aquatic invertebrates, mammals and birds; chronic risk to estuarinelmarine invertebrates and freshwater and estuarinelmarine fish; and risk to nonendangered aquatic vascular plants is not supported by the results ofthis screening risk assessment. Thepresumption of acute risk to freshwater and estuarinelmarine fish and chronic risk to birds could not be determined in this risk assessment dueto the lack ofusable toxicity data. As noted above, propazine may not be applied to selected soils and as such therisk conclusions do not apply to locations where sorghum is grown on these soils. More details on the risk conclusions can be found in the Executive Summary ofthe Ecological Risk Science Chapter for propazine. 1. Risks to Aquatic Organisms
In the conceptual model, spray drift and surface runofflleaching to adjacent bodies of water were predicted as the most likely sources of exposure ofpropazine to nontarget aquatic organisms. Risks to aquatic organisms (i.e. fish, invertebrates, and plants) were assessed based on modeled estimated environmental concentrations (EECs) and available toxicity data. Aquatic EECs for the ecological exposure to propazine were estimated using PRZMIEXAMS employing the standard field pond scenario (Table 11-B3).

a. Animals Fish and Invertebrates Table IV-B1 provides a comparison ofthe peak EECs in surface water to acute toxicity values for freshwater 

### (FW) and estuarinelmarine (EIM) fish and invertebrates. Toxicity studies demonstrate that propazine is moderately toxic to estuarinelrnarine invertebrates following acute exposure; however, at the peak EECs, there were no exceedances ofthe Acute Risk, Acute Restricted Use, or Acute Endangered Species LOCs for estuarinelrnarine invertebrates (Table IV-A2). In a 48- hour flow-through test with freshwater daphnids, no immobilization or sublethal effects were observed at the highest test concentration, resulting in an ECSo of>5.32 ppm ai (mean measured concentration) (MRID 442873-05). The study is scientifically sound but does not fulfill guideline requirements because daphnids were not exposed up to 100ppm ai. Consequently, the acute toxicity ofpropazine to freshwater invertebrates cannot be categorized. If it can be shown that the test was conducted up to the limit of solubility,the study could be upgraded to acceptable. However, for these requested uses, a comparison ofthe highest concentration testedin the daphnid study (5320 ppb) with the highest peak EEC of 89.8 ppb shows that there were no effects in daphnids at concentrations 59 times higher than the highest peak EEC. Therefore, potential acute risk to freshwater invertebrates is expected to be minimal. Toxicity data are unavailable for freshwater and estuarinelmarine fish; consequently, the acute risk for these taxonomic groups following exposure to propazine under the proposed labeled uses remains an uncertainty.

Table IV-B2 provides a comparison ofthe 2 1 

### - and 60-day EECs in surface water to chronictoxicity values for freshwater (FW) and estuarinelmarine (EIM) invertebrates and fish, respectively. Chronic exposure of propazine to estuarinelrnarine invertebrates produced significant effects to reproduction in mysid shrimp at 0.706 ppm ai. However, at the 21-day EEC, the chronic LOC for estuarinelmarine invertebrates was not exceeded (Table IV-A3). Chronic exposure ofpropazine to fathead minnows resulted in significant reductions in length at 1.14mg ai1L and chronic exposure to sheepshead minnow affected embryo survival and hatching success at 2.59 mg ai1L. However, at the 60-day EEC, there were no exceedances of the aquatic chronic LOC for freshwater and estuarinelmarine fish (Table IV-A3). Table IV-B 1. Comparison of Peak EECs of Propazine in Surface Water to Aquatic Acute Toxicity Values

Chronic exposure ofpropazine to freshwater invertebrates produced adverse effects to growth at 0.091 ppm ai. Risk quotients for freshwater invertebrates exceeded the chronic LOC (Table IV-A3) when propazine is applied to sorghum and it is assumed that it reaches the surface waterby runoff andlor leaching at the predicted PRZMIEXAMS EECs. Consequently, freshwater invertebrates inhabiting surface waters adjacent to a propazine treated field would be at risk for adverse effects on survival and growth following chronic exposure to propazine in surface runoff andlor leachate as a result of spray application at the 2 1 -day average EEC for the Kansas and Texas sorghum crop scenarios. Daphnids play a critical role in aquatic food webs by serving as an intermediate between primary producers and fish. Consequently, changes in daphnid populations, either through direct mortality or sublethal (e.g. reproductive, growth) effects, could trigger community- or ecosystem-level responses. When propazine is applied aerially to sorghum, thepredicted aquatic exposurejs 53.2 pg/L for the Kansas scenario and the NOAEC for the daphnid is 47pg/L, indicatingthat the chronic LOC for freshwater invertebrates at the application rate of 1.2lb ai/A is only slightly exceeded for the Kansas scenario. However, when propazine is applied by either aerial or ground spray to sorghum in the Texas scenario, the EEC's are Simulation Scenario

. .. . . . . . - - . - - -. . . . -.

. - - - .. . - Sorghum (1.2 Ib a.i./A) Sorghum (KS)

Aerial spray Ground spray Sorghum (TX)

Aerial spray Ground spray . .. . . . . -.

. -_. . 

### E



### EC's (pg"!).

. .. . - - - - -. .

. Toxicity Values (pgIL) Peak

53.9 40.8
89.8 82.0 . . - -_ - -_ - - -.-. - - - FW Invertebrate ECS0

5,320 21-day

53.2 40.2
88.1 80.4 -- - -

. . . - - - - - -- E/M Invertebrate LCs0

4,200 60-day

52.0 39.5
85.1 77.6 - - - - -- -.-. . - - - FW & EM Fish

N/Aapproximately 1.8 1 times the NOAEC for the sensitive freshwater daphnid. Keeping all parameters in the modeling scenarios the same and assuming that EECs arereduced linearly with application rate reduction, EFED conducted an analysis ofthe effect of rate reduction on chronic RQs for aquatic invertebrates. The chronic RQs for sorghum grown in Texas may be reduced to below the chronic LOC of 1.0 ifthe application rates are reduced by 45% to 0.66 lb ai/A.

RQ exceeded LOC. Table IV-B 2. Comparison of 21- and 60-day EECs of Propazine in Surface Water to Aquatic Chronic Toxicity Values.

b. Aquatic 

### Plants Simulation Scenario .------------------~-~~~~~~.~~~~~~~~~~~~. Sorghum (1.2 Ib a.i./A)

In aquatic plants, propazine produces adverse effects to growth and cell density in both vascular and nonvascular plants. In the duckweed study, an ECsoof0.010ppm a.i. (NOAEC of 0.022 ppm a.i) was determined. Algal ECS0 values ranged from 0.18 to 0.029ppm ai. The fi-eshwaterdiatom, Naviculapelliculosa, was the most sensitive nonvascular aquatic plant, with an NOAEC of 0.0065 ppm ai. For the use scenario modeled for propazine, there are exceedances ofthe endangered LOCs for both vascular and non-vascular aquatic plants for runoffldrift from ground and aerial spray applications to sorghum (Table IV-A4). There were no exceedances ofthe LOC for non-listed vascular aquatic plants for the Kansas and Texas scenarios; however, there were exceedances ofthe LOC for unlisted non-vascular aquatic plants (Table IV-A4), assuming that the maximum predicted propazine concentrations would come in contact with freshwater nonvascular plants. Consequently, both listed vascular and non-vascular plants and unlisted nonvascular plants inhabiting surface waters adjacent to a treated field would be at risk for adverse effects to growth and development when exposed to propazine as a result ofthe labeled use on sorghum. Although there are no listed nonvascular plants, there is concern for indirect effectsto other taxa as these aquatic plants are a basis for food and other needs. The RQs for "endangered" nonvascular plants range from 0.61 for blue-green algae (Kansas, ground application) to 13.37 (Texas, aerial application) for diatoms. Table IV-B3 provides a comparison of the peak EECs in surface water to toxicity values for both listed and unlisted vascular and nonvascular aquatic plants for risks associated with exposure of aquatic plants to propazine by surface runoff andlor leaching. Keeping all parameters in the modeling scenarios the same and assuming that EECs are reduced linearly with application rate reduction, EFED conducted an Sorghum (KS) Aerial spray 53.2 52.0 Ground spray 40.2 39.5 Sorghum (TX) Aerial spray 88.1 85.1 Ground spray 80.4 77.6 EEC's.(l?g'!!).

. . - -. Toxicity Values (pg/L)_ 21-day . . .. . ... -. - - - - - - - - FW Invertebrate

NOAEC

47* 269 720 60-day

1,340 

## - - - --- --- -- - - - - - - - - E/M Invertebrate

NOAEC - -. -.

- - -. - FW Fish NOAEC -. - - - - - - -- - - - --_. EMFish NOAECanalysis ofthe effect ofrate reduction on RQs for aquatic plants. The RQs for the aerial spray to sorghum in the Kansas scenario may be reduced to below the aquatic plant LOC (1.O) ifthe application rates arereduced by 87%to 0.16 lb ai/A. The RQs for the aerial sprayto sorghum in the Texas scenario may be reduced to below the aquaticplant LOC (1.O) if the application rates arereduced by 93% to 0.08 lb ai/A. A complete spray drift analysis for exposures to aquatic plants isprovided in Section IV.B.3. The potential risk to endangered vascular aquatic plants will be discussed in greater detail in Section IV.B.6.

RQ's exceeded LOC's. Table IV-B 3. Comparison of Peak EECs of Propazine in Surface Water to Aquatic Plant Toxicity Values.

2. Risks to Terrestrial Organisms Simulation scenario

----------------.-------.-.-----.-....- Sorghum (1.2 Ib a.i./A)

In the conceptual model, ground deposition from spray application and spray drift with resulting residues on foliage and on flowers and seeds are the most likely sources of propazine exposureto nontarget terrestrial organisms, including listed species. Risks to terrestrial organisms (i.e. birds, mammals, and plants) were assessed based on modeled EECs and available toxicity data. As part ofthe terrestrial assessment, exposure concentrations ofpropazine to nontarget terrestrial plants and animals were modeled according to the labeled application rate for sorghum. For terrestrial birds and mammals, estimates of initial levels ofpropazine residues on various food items, which may be contacted or consumed by wildlife, were determined using the Fletcher nomogram followed by a first order decline model TREX 1.2.3. Likewise, the TerrPlant 1.0 model was used to estimate exposure to nontarget plants and the AgDrift 2.0.1 model provided further refinement of spray drift dispersion and deposition to terrestrial plants located in proximity to treated fields. a. Animals EEC's 

# (~!m
- -. Peak

Birds, Reptiles and Terrestrial-phaseAmphibians Propazine is categorized as at most, slightly toxic to upland gamebirds (bobwhite quail) on an acute oral basis (LDS0 >1,640 mg aikg)and subacute dietary basis (LCso >4,930 ppm ai). The degradate deethylatrazine is also slightly toxic to bobwhite quail. Propazine ispractically nontoxic to waterfowl (mallard) on a subacute dietary basis. Reproduction studies arenot available to assess the risk to upland gamebirds Sorghum (KS)

Aerial spray 53.9 Ground spray 40.8 Sorghum (TX)

Aerial spray 89.8 Ground spray 82.0 * 22* ToxicityValues (

6.5* 100 24.8* . _ - -. - - -. - - - - - - - - - - Endangered

Vascular NOAEC g/L) ;!

-- - -- - -- - -- - - - - - - - - - - -- - - - - - - -- - - - - - - -- - - - - - - - -- - - - - - - - - - - ---

Endangered Nonvascular

NOAEC Nonendangered

Vascular

ECS0 Non-endangered Nonvascular ECsoand waterfowl from 

### developmental/reproductiveeffects following chronic exposure to propazine under the currently proposed labeled uses. Acute RQs were not estimated because the LD50/LCs0'~ were higher than the highest dose/concentration tested. For risk description purposes, the highest doseiconcentration tested was compared with the expected terrestrial EECs. The acute oral LDS0 for bobwhite quail is >1,640 mg ai/kgbody weight and the acute dietary LCs0for bobwhite quail is >4930 pprn food. Assuming the maximum application rate for sorghum and maximum predicted residue levels, the predicted terrestrial EECs from the T-REXmodel (Ver.1.2.3) may be as high as 328 mg/kgbw for 20 g birds on a dosebasis and 288 pprn for short grass on a dietary basis. In the acute oral LDS0 study, there were no mortalities at 1640mg/kgbw (weight adjusted value for 20 gbirds is 1181.5 mglkgbw). Thereisnearly a 4-fold difference between the EEC of 328 mglkgbw and the adjusted LDS0 of 1 181 -5mgkgbw. Therefore, the risk of mortality at these EECs is low. On a dietary basis, again, there were no mortalities at the highest concentration tested (4930 pprn). The differencebetween the dietary concentration of 288 pprn and the LCsoof4930 pprn is more than an order of magnitude. Again, the potential risk ofmortality to birds, reptiles and terrestrialphase amphibians on a dietary basis is likely to be minimal.
In both the acute oral gavage and acute dietary studies, a possible chemical-induced anorexia occurred. Feed consumption and growth were initially affectedby propazine at the 430 mg ailkg dose in the gavage study (MRID 442873-01). The study authors noted that a NOAEC couldbe determined to be 244 mg aikgdue to weight loss up to 72 hours after treatment. 

### In the dietary study with quail, diminished feed consumption, slow growth, and cannibalism were observed at treatments ranging fi-om578 to 4,930 pprn ai (MRID 442873-02). Feed consumption rates and resultant growth were also affected in the dietary study with mallard ducks at all treatment levels (MRID442873-03). In the dietary studies, the study authors could attributethe effects to food avoidance; however, in the oral study, the dose-related loss ofweight was not related to dietary exposure. The authors suggested that the food avoidance may not just be related to feed palatability but rather result from chemically-induced anorexia. No treatment-related mortalities were observed in either study. In order to evaluatepotential sublethal effects associated with acute exposure to propazine on a dose-related basis, the lowest dose (430 mg aikgbw -oral) producing effects (weight loss) are compared to predicted avian doses on food residues (EEC equivalent dose) following the application of propazine at 1.2 lbs ai/A. Table IV-B5 summarizes this comparison. For the use of propazine on sorghum with spray applications of 1.2 Ibs aiIA, thehighest EEC equivalent dose is 328 mg aikg-bw for short grass consumed by a 20g bird. The adjusted LOAEL for 20gbirds is 3 10mgaiikg-bw. Therefore, at the predicted EEC for short grass, weight loss may be expected, indicatingthat there may be risks to acute sublethal effects in birds, reptiles and terrestrial-phase amphibians following spray applications.

# I Table IV-B 4. Comparison of Avian Sublethal Values with Predicted Doses on Food Residuesa I I

short grass Food Type

tall grass

Lbroadleafforage, small insects 

# I

"Acute effect levels: LOAEL: 430 mg ailkg-bw (oral); 578ppm ai (dietary) Weight class (g)

b SeeAppendix D for T-Rex modeling results. No chronic avian studies are available. Decreased body weight and food consumption were observed in the acute avian studies and similar effects were observed in the developmental and reproduction studies in mammals. It is likelythat similar effects would also be observed in the avian reproduction studies. This 1.2 lbs a.i./A

increases the uncertainty ofrisk to birds, reptiles andterrestrial phase amphibians following chronic exposure. Predicted EEC Equivalent Dose (mg aiikg-bw)

Mammals Propazine is classified as practically non-toxic to small mammals on an acute oral basis (LD50 value of >5,050 mg/kg). The degradate deethylatrazine is classified as slightly toxic to small mammals on an acute oral basis (LDS0 values from 

### 668 to 1,881 mg/kg). When RQs are estimated using the LDsO of>5,050 mglkg and assuming the maximum application rate for sorghum and maximum predicted residue levels; neither the Acute Risk, Acute Restricted Use, or Acute Endangered Species Risk LOCs were exceeded (Table 

### IV-B6); consequently, mammals would not be at risk for direct effects on foraging behavior following acute exposure to propazine under the currently proposed labeled uses (Table IV-B6). Adjusted LOAEL (mg ailkg-bw)

Table IV-B 5. Mammalian Acute Risk Quotient Summary a9b,c7d -
Food type

short grass Weight class (g)

15 35 1.2 Ibs a.i./A Predicted maximum Predicted mean residues Residues

0.02 0.0 1 0.02 0.01Table IV-B 5. Mammalian Acute Risk Quotient Summary a,b,c,d 1.2 lbs a.i./A Food type .,, 

### I Predicted maximum Predicted mean Weight class (&, residues Residues

tall grass

seeds, pods 1000 <0.01 <0.01

a Acute toxicity threshold was LDS0 = 5050 mglkg-bw. Detailed calculations ofthe T-REX model (Ver. 1.2.3)and Acute RQs are provided in Appendix D. RQs in this table were calculated for the maximum labeled application rate of 1.2Ibs a.i./A for sorghum. * RQ exceeds the Endangered Species Level of Concern (LOC); RQ > 0.10. 

### ** RQ exceeds the Acute Restricted Use LOC; RQ >0.20. *** RQ exceeds the Acute Risk LOC; RQ > 0.50. broadleaf forage, small insects

fruit, large insects

In a 3-generation reproduction studywith rats, propazine produced decreased body weights in males and females, resulting in a parentalloffspring NOAEC of 5 mg/kg/day. No treatment-related effects on reproduction were observed; consequently, the NOAEC for reproductive toxicity was 250mgkgbwlday. In developmental toxicity studies, administration of propazine by gavageproduced maternal toxicity in both Sprague-Dawley rats and New Zealand rabbits with a NOAEC of 10mgkgbw/day (Table 111-C16). Decreased ossification was also observed in offspring ofrats, resulting in a developmental NOAEC of 

### 10mgkdday. Developmental effects were also observed for the degradates, DEA and DACT in rats at 100ppm ai (fused sternebrae and poor ossification) and 500 ppm ai (embryo resorption and poor ossification), respectively. Based on the rat parentalloffspring toxicity data from the reproduction study and assuming the maximum application rate; the chronic LOC was exceeded for all weight classes ofmammals consuming short grasses, tall grasses, and broadleaf foragelsmall insects at both the maximum and mean predicted residue levels; and for 15 and 35 g mammals consuming fruit and large insects at the maximum predicted residue levels (Table IVA-5). Consequently, 1000 0.01 <0.01

1000

15
35
1000

15 0.01 <0.01
<0.01 <0.01

<o.o 1 <0.01 cO.01 <0.01
<0.01 <O.O 1there arepotential risks to mammals following chronic exposure to propazine when used as directed onthe label.
In order to evaluate potential chronic effects associated with acute exposureto propazine on a dose-related basis, the adjusted NOAEL is compared to predicted mammalian doses on food residues (EEC equivalent dose) for all weight classes and food types for which chronic RQs were exceeded at the application rate 1.2lbs ai/A. Table IV-B7 summarizes this comparison. The dose-based EECs range from 25 times (1

### 5 g mammals consuming short grasses) to 5 times (1000 g mammals consumingtall grasses) the adjusted NOAELs. Keeping all parameters in the modeling scenarios the same and assuming that EECs are reduced linearly with application rate reduction, 

### EFED conducted an analysis ofthe effect ofrate reduction on chronic RQs for mammals. The chronic RQs for sorghum may bereduced to below the chronic LOC of 1.O ifthe application rates are reduced by 

### 83.3% to 

### 0.13 lb ai/A. 

# I Table IV-B 6. Comparison of Mammalian Chronic Toxicity Values with Predicted Doses on Food Residuesa 

## I 1 1 1.2 Ibs a.i./A Food type

lbroadleafforage, small insects1 1000 

## I 24.75 3.85 'NOAEL: 5 mgkg-bwiday short grass

tall grass

Non-target Bene$cial Invertebrates Weight class (g)

15 35

EFED currently does not quantify risks to terrestrial non-target invertebrates. In an acute contact studywith the honey bee, propazine was determined to berelatively non-toxic. At 96 hours, mortality was 2.47% at a dose of 96.69 pghee (Atkins et al. 1975). It isunlikely that there will be risks to pollinators and other beneficial insects at the proposed labeled rates. Dose-based EECs (mgtkg- Adjusted NOAEL bw) (mgtkg-bwtday) 274.59 10.99 189.78 8.89 1000

15
35 1000

15 44.0 3.85
125.85 10.99 86.98 8.89 20.17 3.85
154.45 10.99

### b. Terrestrial Plants Results ofTier I1 toxicity studies with monocots and dicots indicate that seedling emergence and vegetative vigor are severely impacted by exposure to propazine. Seedling emergence, based on shoot weight, was adversely impacted in monocots (onion) at an ECZ5 of 0.035 lb ai/A and in dicots (lettuce) with an EC25of0.016 lb ai/A. Vegetative vigor in monocots, based on shoot weight, was adversely impacted in monocots (wheat) at an EC25of 0.046 lb ai/A and in dicots (cucumber) at an EC25 of 0.10 lb ai/A. The observed effects to monocots and dicots included stunting, chlorosis, necrosis, and plant death.
For the terrestrial use ofpropazine and the maximum application rate of 1.2 lbs a.i./A from aerial spray application, the acute risk LOC was exceeded for nonendangered monocots and dicots located in adjacent areas and in semi-aquatic areas primarily as a result ofrunoff; and for nonendangered monocots and dicots as a result of spray drift. Likewise, the acuterisk LOC was exceeded for nonendangered monocots in semiaquatic areas and nonendangered dicots in adjacent and semi-aquatic areas as the result ofrunoff from ground spray applications. For both ground and aerial spray application, the LOC was exceeded for endangered monocots and dicots located in adjacent and semi-aquatic areas primarily as a result ofrunoff (Table IVA-6). The endangered species LOC was exceeded for monocots and dicots in dry areas exposed to spray drift from both aerial and ground applications. Consequently, nonendangered and endangered monocots and dicots inhabiting dry and semi-aquatic areas adjacent to a treated field wouldbe at risk for adverse effects to growth and development when exposed to propazine as a result ofthe labeled uses. A complete spray drift analysis for exposures to non-target terrestrial plants interrestrial and semi-aquatic areas is provided in Section IV.B.3. Thepotential risk to endangered monocots and dicots will be discussed in greater detail in Section IV.B.6. 

### 3. Spray Drift Analysis The AgDRIFT model (Version 2.01) was used to refine the spray drift exposure estimate for terrestrial plants. Downwind spray drift distances from ground and aerial applications are estimated for possible use in mitigating risks for endangered terrestrial plants that grow in close proximity to agricultural and non-agricultural fields that may be treated with propazine. The model was used to estimate distances (in feet) required to dissipate spray drifi to the most sensitiveNOAEC/EC25levels for monocot and dicot species in the seedling emergence andlor vegetative vigor studies. The standard toxicity level EFED uses for calculating risk quotients for non-endangered terrestrial plants is the EC25.For endangered plants, the NOAEC (or ECos if a NOAEC value is not available) isused. Seedling emergence endpoints arerepresentative of exposure through soil to germinating plants, while vegetative vigor endpoints are representative of foliar exposure. Theterrestrial plant measurement endpoints used in the model are specified in Table IVB-7.Table IVB-7. Agdrift Input Parameters for Tern Study Species

Seedling Emergence: Monocot 

# I Onion Seedling Emergence: Lettuce Dicot Vegetative Vigor: Wheat Monocot 

### I Vegetative Vigor: Cucumber

Dicot 

# 'The fraction of the application rate =NOAEC orthe trial Plant Measurement Endpoint
(Ib ai/A) (Ib ai/A) / /Fraction Fraction

lC25/maximum application rate ofpn Most sensitive parameter

Shoot weight Shoot weight

Shoot weight

Shoot weight

Because the label for propazine does not specify release height or droplet size for ground applications, the AgDRIFT model was run for all four scenarios (high boom and fine spray, low boom and fine spray,high boom and medium/coarse spray, and low boom and medium/coarse spray) to provide a range ofdistances (in feet) required to dissipate spray drift to the most sensitiveNOAEC/EC25levels. All droplet size descriptions are based onASAE S-572 standard definitions. High and low boom heights arerepresentative of4 and 2 foot release heights, respectively. AgDRIFT outputs for ground boom applications estimate the 5oth and 90" percentile ofdata collected from field trials. For this analysis, the 9oth percentile was used to provide protective dissipation distances. Available toxicity data indicate that the terrestrial plants are most sensitiveto propazine via soil uptake rather than application ofthe herbicide directly to post-emergent foliage. Therefore, downwind spray drift distances based on the NOAEC and EC25values derived from SE toxicity tests were utilized and arebelieved to be protective ofboth endangered and non-endangered terrestrial plants, respectively. A summary ofthe results ofthe Tier 1AgDRIFT modeling for ground and aerial application of propazine are presented in Tables IVB-8 and IVB-9. Thetables summarize the downwind distances required to dissipate spray drift for endangered species (Table IVB-8 with the 

### NOAEC levels) and non-endangered species (Table IVB-9 with the 

### EC25 values) for both monocot and dicot terrestrial plant species and for both ground and aerial applications ofpropazine. Modeled drift dissipation distances for endangered species, based on ground boom applications are expected to range from approximately >I20 to 500 feet for very fine to fine droplet sizes and from >46 to 200 feet for fineto medium/coarse droplet sizes (the >values are dueto the NOAEC value of <0.01). Over the range ofmodeled droplet sizes, the protective spray drift distances for endangeredmonocots range from >46 to >285 feet and for endangered dicots, 120to 500 feet. Modeled dissipation distances for endangered monocots and dicots, based on aerial application ofpropazine, using the default fine to medium droplet sizes are uncertain because they exceed the 1,000 foot limit ofthe model. For medium to coarse droplet sizes, the expected dissipation distances are again uncertain because they range from >570 to >I000 feet (again, the value of > 570 feet is dueto the NOAEC value of<0.01).Modeled drift dissipation distances for non-endangered species, based on ground boom applications are expected to range from approximately 30to 190feet for very fine to fine droplet

- - sizes and from 10to 50 feet for fine to mediumlcoarsedroplet sizes. Over the range ofmodeled droplet sizes, the protective spray drift distances for monocotsrange from 10to 90 feet and for dicots, 26 to 190 feet. Modeled dissipation distances for non-endangered monocots and dicots, based on aerial application ofpropazine, using the default fine to medium droplet sizes are expected to range fiom 325to 830 feet. For medium to coarse droplet sizes, the expected dissipation distances range from approximately 1 80to 341 feet.

Table IVB-8. Summary ofAgDRl Crop

Monocots (onion) Low Boom (20 inches) High Boom (50 inches) Dicots (lettuce) Low Boom (20 inches) High Boom (50 inches) 

### * The maximum dissipation distance 'TModeling Results for Endangered Plant Species Distance Required to Dissipate Spray Drift to NOAEC Levels for Ground Application (feet) Droplet Size

>I21 

## 1 >46 

## I NIA 

## I NIA Distance Required to Dissipate Spray Drift to NOAEC Levels for Aerial Application (feet) Droplet Size Very Fine to Fine

>285 

# 1 >85 

# I NIA 

# I NIA I I I

263 

## I 118 

## I NIA 

## I NIA Fine to MediumlCoarse

Table IVB-9. Summary ofAgDRIFT Modeling Results for Non-Endangered Plant Species 

# 1 Fine to Medium

492

Crop Medium to Coarse

om the edge of the field in the Tier I ground model is 1,000 feet. 200



# I Droplet Size 

# I Droplet Size 

# I Distance Required to Dissipate Spray Drift to ECZs Levels for Ground Application (feet) NIA

- Distance Required to Dissipate Spray Drift to ECZs Levels for Aerial Application (feet) NIA

Very Fine to Fine Monocots (onion)

High Boom (50 inches) 

# I 89 

# I 20 

# I NIA 

# I NIA 

# 1 Fine to MediumlCoarse

Low Boom (20 inches)

Dicots (lettuce) 

# 1 1 1 830 

# 1 341 

# 1 I I I I 325

Low Boom (20 inches) 

# I 72 

# I 26 

# I NIA NIA Fine to Medium

180 

# I NIA 33 Medium to Coarse

10

High Boom (50 inches) NIA

"he maximum dissipation distance from the edge of the field in the Tier I ground model is 1,000 feet. 187 46 NIA NI AThe current label provides appropriate information on spray drift management to guide the applicator while providing few specific requirements for minimizing spray drift. Given that some of thepredicted spray drift distances are large, that there are associated uncertainties for aerial application ofpropazine and the fact that the NOAEC for monocots is not defined (i.e., it is a <value), ifmitigation ofrisk is desired, then it is recommended that the label language for spray drift require specific spray drift mitigation measures (i.e., lower release heights, wind speed restrictions, and specification of spray droplet sizes). 4. Review of Incident Data Incident reports submitted to EPA since approximately 

### 1994have been tracked by assignment of EIIS (Environmental Incident Information System) in an Incident Data System (IDS). There are no incident reports for propazine. 5. Endocrine Effects
In March 2002, based on the available weight-of-evidence, the Agency's Health Effects Division (HED) determined that atrazine, simazine, propazine, and their degradates, DEA, DIA, and DACT can be grouped by a common mechanism oftoxicity for neuroendocrine effects (disruption of the hypothalamic-pituitary-gonadal 

### (HPG) axis). Based on these effects in mammals and endocrine effects in other taxonomic groups with the above triazine-containing pesticides and degradates, propazine and its degradates may be classified as potential endocrine disruptors. EPA isrequired under the Federal Food, Drug, and Cosmetic Act (FFDCA), as amended by the Food QualityProtection Act (FQPA), to develop a screening program to determine whether certain substances (including all pesticide active and other ingredients) "may have an effect in humans that is similar to an erectproduced by a naturally occurring estrogen, or other such endocrine effectsas theAdministrator may designate." Following the recommendations of its Endocrine Disruptor Screening and Testing Advisory Committee (EDSTAC), EPA determined that there was a scientific basis for including, as part of theprogram, the androgen and thyroid hormone systems, in addition to the estrogen hormone system. EPA also adopted EDSTAC's recommendation that the Program include evaluations of potential effects in wildlife. For pesticide chemicals, EPA will use the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) and, to the extent that effects in wildlife may help determine whether a substance may have an effect in humans, FFDCA authority to require the wildlife evaluations. As the science develops and resources allow, screeningof additional hormone systems may be added to the Endocrine Disruptor ScreeningProgram (EDSP). When the appropriate screening and/or testing protocols being considered under the Agency's EDSP have been developed, propazine may be subjected to additional screening and/or testing to better characterize effectsrelated to endocrine disruption.6. 

### Federally Threatened and Endangered (Listed) Species Concerns a. Action Area For listed species assessment purposes, the action area is considered to be the area affected directly or indirectly by the Federal action and not merely the immediate area involved in the action. At the initial screening-level, the risk assessment considers broadly described taxonomic groups and conservatively assumes that listed species within those broad groups are co-located with the pesticide treatment area. This means that terrestrial plants and wildlife are assumed to be located on or adjacent to the treated site and aquatic organisms are assumed to be located in a surfacewater body adjacent to the treated site. The assessment also assumes that the listed species are located within an assumed area which has therelatively highest potential exposure to thepesticide, and that exposures are likely to decrease with distance from the treatment area. Section II.A.4 ofthis risk assessment presents thepesticide use sites that are used to establish initial collocation of species with treatment areas. Ifthe assumptions associated with the screening-level action area result in RQs that arebelow the listed species LOCs, a "no effect" determination conclusion is made with respect to listed species in that taxa, and no further refinement of the action area is necessary. Furthermore, RQs below the listed species LOCs for a given taxonomic group indicate no concern for indirect effects upon listed species that depend upon the taxonomic group covered by the RQ as a resource. However, in situations where the screening assumptions lead to RQs in excess of the listed species LOCs for a given taxonomic group, a potential for a "may affect" conclusion exists and may be associated with direct effects on listed species belonging to that taxonomic group or may extend to indirect effects upon listed species that depend upon that taxonomic group as a resource. In such cases, additional information on the biology of listed species, the locations of these species, and the locations ofuse sites and could be considered along with available information on the fate and transport properties ofthe pesticide to determine the extent to which screening assumptions regarding an action area apply to a particular listed organism. These subsequent refinement steps could consider how this information would impact the action area for a particular listed organism and may potentially include areas of exposure that are downwind and downstream ofthe pesticide use site. For this risk assessment for propazine, a "no effect" determination cannot be made for any species because both aquatic and terrestrial plants are affectedbypropazine under the proposed uses and all other species may be indirectly affected fi-omeffects to aquatic andlor terrestrial plants. b. 

### Taxonomic Groups Potentially at Risk Thepreliminary risk assessment for endangered species indicates that propazine exceeds the Endangered Species LOCs for the specified use scenario for the following taxonomic groups:aquatic vascular plants at the maximum application rate by ground and aerial spray application, aquaticnon-vascular plants at the maximum application rate by ground and aerial spray application (although none are listed as endangered, there may be concerns for other taxa with obligate relationships with these species), non-target terrestrial plants -endangered monocots and dicots adjacent to treated areas and in semi-aquatic areas at the applicationrateby ground and aerial spray application; endangered monocots and dicots in dry areas exposed to spray drift byboth aerial and ground application at the applicationrate, Listed mammals (chronic exposure) at the maximum application rate by ground and aerial spray application, Listed freshwater invertebrates (chronic exposure) at the maximum application rate by ground and aerial spray application, AgDrift model predicts LOC exceedances for listed plant species at distances of more than 1000 feet for aerial application and up to 148feet for ground applications from the edge of the field, AgDriftmodel predicts exceedances of LOC for listed terrestrial plant species inhabiting ponds and wetlands exposed from spray drift due to agricultural use at distances up to 100feet from areas treated via aerial applications. Likewise, the model predicts LOC exceedances for listed aquatic plants inhabiting wetlands exposed from spraydrift at distances of zero up to 

### 62 feet from treated areas as the result of aerial spray applications. Table IVB-I0 summarizes the listed species at risk associated with either direct or indirect effects following application ofpropazine at the requested rates.

Concerns For Federally Listed as Endangered and/or Threatened Species
Table IVB-10. Listed speciesrisks associated with direct or indirect effects due to applications of propazine on sorghum Listed Taxon Terrestrial and semi-aquatic plants - monocots

Terrestrial and semi-aquaticplants - dicots

Terrestrial invertebrates

Birds

Terrestrial-phase amphibians Direct Effects Yes

Yes

No for terrestrial insects; unknown for other terrestrial invertabrates (insufficient data) Possible:no chronic avian data; sublethal effectsin acute studies coupled with similar effects in mammalian reproduction study increase uncertaintyfor birds. Possible:no acute or chronic data and no chronic avian data Indirect Effects Yes through effects to pollinators (mammals; uncertain with birds, reptiles, terrestrial-phase amphibians) Yes through effects to pollinators (mammals; uncertain with birds, reptiles, terrestrial-phase amphibians) Yes through effects to terrestrial

and aquatic plants (food and habitat) Yes through effects to terrestrial

and aquatic plants (food and habitat), mammals, freshwater invertebrates)
Yes through effects to terrestrial

and aquatic plants (food and

## I Table IVB-10. Listed speciesrisks associatedwith direct or indirect effects due to applications of propazine on 

## I

I invertebrates) Reptiles 

## I Possible:no acute or chronic 

## I Yes through effects to terrestrial Listed Taxon

Aquatic-phase amphibians (see comment forbirds) 

## I habitat), mammals, freshwater Direct Effects

Mammals
Aquatic non-vascular plants* Aquatic vascular plants Freshwater fish Indirect Effects

data and no chronic avian data (see comment forbirds) Yes with chronic exposure.

Yes Yes Unknown with acute exposure (no acute data);No after chronic exposure. Unknown with acute exposure (no acute data); using chronic data on fish as surrogate -No and aquatic plants (food and habitat), mammals, freshwater invertebrates) Yes through effects to terrestrial

and aquatic plants, mammals,

freshwater invertebrates. No No Yes through effects to terrestrial plants (stream quality), aquatic

plants (food and habitat) and freshwater invertebrates (food) Yes through effects to terrestrial plants (stream quality), aquatic

plants (food and habitat) and
Freshwater crustaceans

Mollusks surrogate -No after acute exposure and Yes after chronic exposure.

### - after chronicexposure. Using data on daphnia as plants (stream quality), aquatic plants (food and habitat) and other freshwater invertebrates freshwater invertebrates (food) Yes through effects to terrestrial

No after acute exposure;Using chronic data on crustaceans as

surrogate - NOafter chronic Yes through effects to terrestrial plants (stream quality) and aquatic plants (food and habitat).
Marinelestuarinefish

invertebrates (food) Vt the present time no aquatic non-vascular plants are included in Federal listings of threatened and endangered species. The Marinelestuarine crustaceans

taxono~nic group is included here for the purposes of evaluating potential contributions to indirect effects tobther taxa and as a record of exceedences should future listings of non-vascular aquatic plants warrant additional evaluation of Federal actions. exposure. Unknown: no acute data No after chronic exposure.

1. Discussion 

### ofRisk Quotients Yes through effects to terrestrial plants (tributarylestuaryquality)

and aquatic plants (food and
No after acute and/or chronic exposure.

TheAgency's LOCs for aquatic vascular plants, non-target terrestrial plants, mammals and freshwater invertebrates are exceeded for the use of propazine as outlined in previous sections. Should estimated exposure levels occur in proximity to listed resources, the available screeninglevel information suggests a potential concern for direct effects on listed species within these taxonomic groups listed above associated with the use of propazine as described in Section II.A.4. The registrant must provide information on the proximity of Federally listed aquatic vascular plants, non-target terrestrial plants, habitat) Yes through effects to terrestrial plants (tributarylestuaryquality), aquatic plants (food and habitat) and other marinelestuarinemammals and freshwater invertebrates to the propazine use sites. This requirement may be satisfied in one ofthree ways: I)having membership in the FIFRA Endangered Species Task Force (Pesticide Registration [PR] Notice 2000-2); 2) citingFIFRA Endangered Species Task Force data; or 3) independently producing these data, provided the information is of sufficient quality to meet FIFRA requirements. The information will beused by the OPP Endangered Species Protection Program to develop recommendations to avoid adverse effects to listed species. 

### 2. Probit Dose Response Relationship A probit dose response analysis was performed for toxicity studies for which slopes with 95% confidence intervals were available (only marine invertebrates (mysid shrimp)). Theprobit slope response relationship is evaluated to calculate the chance of an individual event corresponding to the listed species acute LOCs. The analysisuses the EFED spreadsheet IECvl



### .1.xls, developed by Ed Odenkirchen (6122104). It is important to note that the IEC model output can go ashigh as 1 x 10'~ or as low as 1 x 10-16 in estimating the event probability. This cut-off is a limit in the Excel spreadsheet environment and is not to be interpreted as an agreed upon upper or lower bound threshold for concern for individual effects in any given listed species. EstuarinelMarine Invertebrates: Based on an assumption of a probit dose response relationship with a mean estimated slope of 2.0, the corresponding estimated chance of individual mortality associated with the listed species LOC of 0.05 the acute toxic endpoint for estuarinelmarine invertebrates is -1 in 2.16 x 1 02. It isrecognized that extrapolation ofvery low probability events is associated with considerable uncertainty in the resulting estimates. To explore possible bounds to such estimates, the upper and lower values for the mean slope estimate (2.94 - 9.1 1) were used to calculate upper and lower estimates ofthe effects probability associated with the listed species LOC. These values are -1 in 1.53 x lo4and >1 in 1x 1016,respectively. 3. Data Related to Under-representedTaxa Effects data on under-represented taxonomic groups were not submitted by the Registrant. In addition, effects data from other analyzed sources (ECOTOX Database, PAN Database) were not obtained for this screening risk assessment. 4. Implications of SublethalEffects Sublethal effects (reduced food consumption and weight loss) were observed in the acute avian studies. These effects were observed at levels higher than the estimated terrestrial EECs and thus may be observed at the proposed use rates. Chronic studies were available for aquatic fish and invertebrates and for mammals. The chronic LOC was exceeded for freshwater invertebrates. Chronic exposure ofpropazine to freshwater invertebrates produces adverse effects to growth at 0.091 ppm ai. These growth effects may result in adverse effects to the populations ofinvertebrates thus potentially impacting other dependent trophic levels. Chronic RQs exceeded the chronic LOC formammals in all weight classes (15 g, 

### 35 

### g, and 1000g) for consumption of short grasses, tall grasses and broadleaf foragelsmall insects at the application rate modeled and maximum and mean predicted residue levels; and for 15 and 35 g mammals for consumption of fruit and large insects at the application rate and maximum predicted residue levels. In a 3-generation reproduction study with rats, propazine produced decreased body weights in males and females at doses of 50mg/kg/daywith a NOAEL of 5 mg/kg/day (MRID 000414-09). The growth-related effects observed in these studies may lead to a potential concern for impacts to populations ofmammals consuming feed items contaminated with propazine and to the predators that feed on them. c. Indirect Effects Analysis The Acute and Endangered Species LOCs for non-target monocots and dicots were exceeded for plants located adjacent to treated areas, in semi-aquatic areas, and by drift for the scenarios analyzed. The guideline terrestrial plant studies indicate direct adverse effectsto seedling emergence and vegetative vigor, as well as non-lethal effects including stunting, chlorosis, necrosis and plant death. The LOC for endangered species was exceeded for freshwater vascular plants for runoffldrift from ground and aerial spray applications to sorghum. In the guideline aquatic vascular plant studies, concentrations as low as 0.10 mg/L resulted in inhibition of plant growth and reduction of frond count. Damage to non-target plants may be sufficient to prevent theplant fiom competing successfully with other plants for resources and water. Endangered plant species may be especially impacted by exposure to propazine because ofthe impact ofthe loss of a few individuals to thepopulation. Consequently, there is apotential concern for listed species with either broad or narrow dependencies on impacted plant species/populations/communities for habitat, feeding or cover requirements. In terrestrial and shallow-water aquatic communities, plants are the primary producers upon which the succeedingtrophic levels depend. Ifthe available plant material is impacted dueto the effects ofpropazine, this may have negative effects not only on the herbivores, but throughout the food chain. Also, depending on the severity ofimpacts to the plant communities [i.e., forests, wetlands, ecotones (edge and riparian habitats)], community assemblages and ecosystem stabilitymay be altered (i.e. reduced bird populations in edge habitats; reduced riparian vegetation resulting in increased light penetration and temperature in aquatichabitats, loss of cover and food for fish). The chronic LOC for mammals was exceeded in all weight classes for selected food categories. Plants dependent upon mammals for pollination and birds, other mammals, reptiles and terrestrial amphibians dependent upon small mammals for food may be impacted by decreasing mammal populations. Similarly,the chronic LOC for freshwater invertebrates was exceeded with the proposed propazine application rates and uses. Birds, amphibians, reptiles, mammals, fish and other aquatic invertebrates may be impacted by decreasing freshwater invertebrate populations.d. Critical Habitat
In the evaluation of pesticide effects on designated critical habitat, consideration is given to the physical and biological features (constituent elements) of a critical habitat identified by the U.S Fish and Wildlife and National Marine Fisheries Services as essential to the conservation of a listed species and which may require special management considerations or protection. The evaluation ofimpacts for a screening level pesticide risk assessment focuses on the biological features that are constituent elements and is accomplished using the screening-level taxonomic analysis (risk quotients, RQs) and listed species levels of concern (LOCs) that areused to evaluate direct and indirect effects to listed organisms. The screening-level risk assessment has identified potential concerns for indirect effects on listed species for those organisms dependant upon aquatic vascular and non-vascular plants, terrestrial plants and terrestrial plants growing in semi-aquatic areas, mammals and freshwater invertebrates. In light ofthe potential for indirect effects, the next step for EPA and the Service(s) is to identify which listed species and critical habitat are potentially implicated. Analytically, the identification of such species and critical habitat can occur in either oftwo ways. First, the agencies could determine whether the action area overlaps critical habitat or the occupied range of any listed species. If so, EPA would examine whether the pesticide's potential impacts on non-endangered species would affect the listed species indirectly or directly affect a constituent element of the critical habitat. Alternatively, the agencies could determine which listed species depend onbiological resources, or have constituent elements that fall into, the taxa that may be directly or indirectly impacted by the pesticide. Then EPA would determine whether use ofthepesticide overlaps the critical habitat or the occupied range ofthose listed species. At present, the information reviewed by EPA does not permit use of either analytical approach to make a definitive identification of species that are potentially impacted indirectly or critical habitats that ispotentially impacted directly by the use ofthe pesticide. EPA and the Service(s) are working together to conduct the necessary analysis. This screening-level risk assessment for critical habitat provides a listing ofpotential biological features that, if they are constituent elements ofone or more critical habitats, would be ofpotential concern. These correspond to the taxa identified above asbeing of potential concern for indirect effects and include the following: mammals, freshwater invertebrates, aquatic vascular and non-vascular plants, terrestrial plants and terrestrial plants growing in semi-aquatic areas. This list should serve as an initial step in problem formulation for further assessment ofcritical habitat impacts outlined above, should additional work be necessary. e. Co-occurrence Analysis Sincethere are potential direct and/or indirect effects on all taxa, LOCATES was run for all taxonomic groups. The LOCs for terrestrial monocots, dicots and aquaticplants as well as chronic LOCs for freshwater invertebrates and mammals were exceeded;consequently a potential concern arises for species with both narrow (i.e., speciesthat are obligates or have very specific habitat or feeding requirements) and general dependencies (i.e., cover type requirements). Information from LOCATES, as presented in Table IV

### B 10below, indicates that for propazine, a number ofpotentially affected species of plants, mammals and freshwater invertebrates appear to be co-located with pesticide use areas. Consequently, there may be a concern for potential indirect effects to listed species dependent upon mammals that consume feed items contaminated with propazine residues and freshwater invertebrates that live in propazine contaminated water such as predatory birds, fish, amphibians, reptiles and mammals. In addition, there may be a potential concern for indirect effects related to plants that require mammals for pollination or seed dispersal and for animals that require terrestrial andlor aquatic vegetation for food, habitat and/or stream quality.

### Table 

### IV-B 11 Unique Taxa Count by State for Sorghum Colorado, New Mexico, Kansas, Nebraska, Oklahoma, Texas, SouthDakota, Arizona, Califomia, North Carolina, Maryland, Louisiana, Mississippi, Arkansas, Tennessee, Kentucky, Missouri, Illinois Amphibian Arachnid Bird Bivalve Crustacea Dicot Ferns FishGastropod Insect Lichen Mammal Marine Monocot Reptile Counties: 32 8 763 147 27 206 1 294 7 69 5 414 7 7 1 54 States: 4 2 18 10 8 15 1 18 6 13 1 18 1 13 8 Species: 11 11 28 51 13 118 1 58 9 20 1 29 I 18 14

### C. Description of Assumptions, Limitations, Uncertainties, Strengths, and Data Gaps 1. Uncertainties, assumptions, and limitations associated with models Aauatic Models Extrapolating the risk conclusions from the standardpond scenario modeled by PRZM/EXAMS may either underestimate or overestimate thepotential risks. Major uncertainties with the standard runoff scenario are associated with the physical construct of the watershed and representation ofvulnerable aquatic environments for different geographic regions. Thephysicochemical properties (pH, redox conditions, etc.) of the standard farm pond arebased on a Georgia farm pond. Theseproperties are likely to be regionally specific because of local hydrogeological conditions. Any alteration in water quality parameters may impact the environmental behavior ofthepesticide. The farm pond represents a well mixed, static water body. Because the farm pond is a static water body (no flow through), it does not account for pesticide removal through flow through or accidental water releases. However, the lack of water flow in the farm pond provides an environmental condition for accumulation of persistent pesticides. The assumption of uniform mixing does not account for stratification due to thermoclines (e.g., seasonal stratification in deep water bodies). Additionally, thephysical construct ofthe standard runoff scenario assumes a watershed:pond area ratio of 10. This ratio isrecommended to maintain a sustainable pond in the Southeastern United States. Theuse ofhigher watershed:pond ratios (as recommended for sustainable ponds in drier regions of the United States) may lead to higher pesticide concentrations when compared to the standard watershed:pond ratio. The standard pond scenario assumes that uniform environmental and management conditions exist over the standard 10hectare watershed. Soils can vary substantially across even small areas, and thus, this variation isnot reflected in the model simulations. Additionally, the impact ofunique soil characteristics (e.g., fragipan) and soil management practices (e.g., tile drainage) are not considered in the standard runoff scenario. The assumption ofuniform site and management conditions isnot expected to represent some site-specific conditions. Extrapolating the risk conclusions from the standard pond scenario to other aquatic habitats (e.g., marshes, streams, creeks, and shallow rivers, intermittent aquatic areas) may either underestimate or overestimatethe potential risks in those habitats. There are limited monitoring studies for propazine in freshwater environments and no studies in marine environments; therefore, the exposure of aquatic species to propazine is based entirely on the modeled data. The output ofmodels such as PRZMIEXAMS is dependent upon the quality ofthe environmental fate input parameters. No aquatic dissipation studies are available, and an assumption regarding the half-life ofpropazine in aqueous bodies such as lakes, ponds, etc. had to be made from laboratory data on the aerobic soil degradation half-life. Future monitoring studies and aquatic dissipation field studies would be useful in order to determine how well the modeled results fit measured levels ofpropazine in aquatic environments following its application to sorghum at appropriaterates.Terrestrial Models The data availableto support the terrestrial exposure assessment for propazine are substantially complete, with the exception of a foliar dissipation study, which is an input variable for modeling ofrisks to birds and mammals (i.e.,T-REX). Theterrestrial modeling was conducted using a default foliar half-life value of 35 days. Use ofthis default value could overestimate the foliar half-life for propazine, higher terrestrial EECs, and risk. However, it should be noted that because the EEC represents the concentration immediately following a direct application, the foliar half-life variable is only influential for scenarios involvingmultiple applications. As discussed earlier in the exposure section ofthis document, the Agency relies on the work ofFletcher et al. (1994) for setting the assumed pesticide residues in wildlife dietary items. The Agency believes that these residue assumptions reflect a realistic upper-bound residue estimate, although the degree to which this assumption reflects a specificpercentile estimate is difficult to quantify. It is important to note that the field measurement efforts used to develop the Fletcher estimates ofexposure involve highly varied sampling techniques. It is entirely possible that much of these data reflect residues averaged over entire above ground plants in the case of grass and forage sampling. Depending upon a specific wildlife species' foraging habits, whole aboveground plant samples may either underestimate or overestimate actual exposure. The acute and chronic characterizations ofrisk rely on comparisons ofwildlife dietaryresidues with LC5() or NOAEC values expressed in concentrations of pesticides in laboratory feed. These comparisons assume that ingestion of food items in the field occurs at rates commensurate with those in the laboratory. Although the screening assessment process adjusts dry-weight estimates of food intake to reflect the increased mass in fresh-weight wildlife food intake estimates, it does not allow for gross energy and assimilative efficiency differences between wildlife food items and laboratory feed. On gross energy content alone, direct comparison of a laboratory dietary concentration-based effects threshold to a fresh-weight pesticide residue estimate would result in an underestimation of field exposure by food consumption by a factor of 1.25

### - 2.5 for most food items. Only for seeds would thedirect comparison ofdietarythreshold to residue estimate lead to an overestimate of exposure. Differences in assimilative efficiency between laboratory and wild diets suggest that current screening assessment methods do not account for a potentially important aspect of food requirements. Depending upon species and dietary matrix, bird assimilation ofwild diet energy ranges from 23 - 

### 80%, and mammal's assimilation ranges fkom 41 

### - 85% 

### (U.S. Environmental Protection Agency, 1993). If it is assumed that laboratory chow is formulated to maximize assimilative efficiency (e.g., a value of 85%), a potential for underestimation of exposure may exist by assuming that consumption of food in the wild is comparable with consumption during laboratory testing. In the screening process, exposure may be underestimated because metabolic rates arenot related to food consumption.For the terrestrial organism risk assessment, the EECs on food items generated using T-REX may be compared directly with dietary toxicity data or converted to an oral dose to calculate chronic dose-based RQs, as is the case for small mammals. The screening-level risk assessment for propazine uses upper bound predicted residues as the measure of exposure. For mammals, the residue concentration is converted to daily oral dosebased on the fraction ofbody weight consumed daily as estimated through mammalian allometric relationships. Converting to the oral dose-based chronic RQs from the reported mammalian dietary chronic endpoint allows EFED to evaluate the risk to different size-classes ofmammals with varying feeding habits. However, this extrapolation method for generating dose-based chronic RQs for smaller animals based on dietary-based data for larger animals, may also increase uncertainty in this risk assessment. Finally, the screening procedure does not account for situations where the feeding rate may be above orbelow requirements to meet free livingmetabolic requirements. Gorgingbehavior is 

### a possibility under some specific wildlife scenarios (e.g.,bird migration) where the food intake rate may be greatly increased. Kirkwood (1983) has suggested that an upper-bound limit to this behavior might be the typical intake rate multiplied by a factor of 5. In contrast is the potential for avoidance, operationally defined as animals responding to the presence ofnoxious chemicals in their food by reducing consumption of treated dietary elements. This response is seen in nature where herbivores avoid plant secondary compounds. 2. Uncertainties,assumptions, and limitation associatedwith exposure scenarios Screening-level risk assessments for spray applications ofpesticides consider dietary exposure alone. Other potential routes of exposure to propazine for terrestrial organisms are discussed below. Incidental soil ingestion exposure This risk assessment does not consider incidental soil ingestion. Available data suggests that up to 15%ofthe diet can consist of incidentally ingested soil depending on the species and feeding strategy (Beyer et al., 1994). A simple first approximation of soil concentration ofpesticide from spray application shows that ingestion of soil at an incidental rate ofup to 15%ofthe diet would not increase dietary exposure. Inhalation exposure The screeningrisk assessment does not consider inhalation exposure. Such exposure may occur through three potential sources: (1) spraymaterial in droplet form at the time of application (2) vapor phase pesticide volatilizing from treated surfaces, and 

### (3) airborneparticulate (soil, vegetative material, and pesticide dusts). Available data suggest that inhalation exposure at the time of application is not an appreciable route of exposure for birds. According to research on mallards and bobwhite quail, respirable particle size in birds (particles reaching the lung) is limited to a maximum diameter of 2 to 5 microns. The spray droplet spectra covering the majority ofpesticide application situations (AgDRIFT model scenarios for very-fineto coarse droplet applications) suggeststhat lessthan 1 % ofthe applied material is within the respirable particle size. Theoretically, inhalation ofpesticide's active ingredient in the vapor phase may be another source of exposure for somepesticides under some exposure situations. However, volatilization of propazine from water and soil surfaces is not expected; therefore, inhalation should not be an important exposure pathway. The impact from exposure to dusts contaminated with thepesticide cannot be assessed generically because soil properties (chemical and physical), which impact the estimation of such exposures are highly site-specific. Dermal Exposure The screening assessment does not consider dermal exposure, except as it is indirectly included in calculations of RQsbased on lethal doses per unit ofpesticide treated area. Dermal exposure may occur through three potential sources: (1) direct application of spray to terrestrial wildlife in the treated area or within the drift footprint, (2) incidental contact with contaminated vegetation, or 

### (3) contact with contaminated water or soil. Data which address dermal exposure of wildlife to pesticides in a quantitative fashion are extremely limited. The Agency is actively pursuing modeling techniques to account for dermal exposure via direct application of spray and by incidental contact with vegetation. Drinking Water Exposure The exposure of a target organism to a pesticide's active ingredient may be theresult of consumption of surface water, groundwater or consumption ofthe pesticide in dew or other water on the surfaces of treated vegetation or in puddled water on treated fields. For the active ingredients of a pesticide there is a potential to dissolve in runoff and puddles on the treated field may contain the chemical. However, propazine exhibits limited solubility; consequently, the potential for drinking water exposure shouldbe reduced. 

### 3. Uncertainties, assumptions, and limitation associated with the toxicity data Species Selection and Sensitivity There are a number of areas ofuncertainty in the terrestrial and the aquatic organism risk assessments that could potentially cause an underestimation ofrisk. Use oftoxicity data on representative species does not provide information on the potential variability in susceptibility to acute and chronic exposures. For screening terrestrial risk assessments, a generic bird ormammal is assumed to occupy either the treated field or adjacent areas receiving the pesticide at a rate commensurate with the treatment rate on the field. The actual habitat requirements of anyparticular terrestrial species arenot considered, and it is assumed that species occupy, exclusively and permanently, the treated area being modeled. This assumption leads to a maximum level of exposure in therisk assessment.Although the screening risk assessment relies on a selected toxicity endpoint from the most sensitive species tested, it does not necessarily mean that the selected toxicity endpointsreflect sensitivity ofthe most sensitive species existingin a given environment. The relative position ofthe most sensitive species tested in the distribution of all possible species is a function ofthe overall variability among species to a particular chemical. In the case of listed species, there is uncertainty regarding the relationship ofthe listed species' sensitivity and the most sensitive species tested. Surrogates were used to predict potential risks for species with no data (i.e., reptiles and amphibians). It was assumed that the use of surrogate effects data is sufficiently conservative to apply to the broad range of species within taxonomic groups. Ifother species aremore or less sensitive to propazine than the surrogates, risks may be under- or overestimated, respectively. Aae class and sensitivity of effects thresholds Scientistsgenerally recognize that the age ofthe test organism may have a significant effect on the observed sensitivity to a toxicant. In a screening-level assessment of acute toxicity in fish, data are collected on juveniles weighing 0.1 to 5 grams. For aquatic invertebrates, the recommended acute testing isperformed on immature age classes (e.g., first instar for daphnids, second instar for amphipods, stoneflies and mayflies, and third instar for midges). Similarly, acute dietary testing with birds is also performed on juveniles, with mallard ducks tested at 5-10 days of age and quail at 10-14days of age. Testing ofjuveniles may overestimate the toxicity ofdirect acting pesticides in adults. As juvenile organisms do not have fully developed metabolic systems, they may not possess the ability to transform and detoxify xenobiotics equivalent to the olderladult organism. The screeningrisk assessment has no current provisions for a generally applied method that accounts for this uncertainty. In so far as the available toxicity data may provide ranges of sensitivity information with respect to age class, the risk assessment uses the most sensitivelife-stage information as the conservative screening endpoint. 4. 

### Uncertainties and assumptions associated with gaps in environmental fate and toxicity data The following data gaps and uncertainties were identified with respect to the submitted ecotoxicity effects data: $ Acute risks for freshwater fish were not characterized because the submitted study was determined to be invalid based on solubility issues. The acute freshwater invertebrate study was also determined to be supplemental. A high degree of uncertainty exists for the freshwater toxicity data forpropazine until it can be shown that theresults reflect that the tests were conducted up to the limit of solubility. An acceptable study will improve the certainty ofthe risk assessment. $ Chronicrisk to avian species was not characterized because no studies with the TGAI were submitted.$ Current data are not available to assess potential risk ofpropazine degradates to aquatic fish and invertebrates and terrestrial plants. $ Dermal contact and soil ingestion pathways for terrestrial mammals and birds were not evaluated because these routes of exposure are not considered in deterministic risk assessments. Data which address dermal exposure ofwildlife to pesticides in a quantitative fashion are extremely limited. TheAgency is actively pursuing modeling techniques to account for dermal exposure via direct application and by incidental contact. $ Risks to semiaquatic wildlife via consumption ofpesticide-contaminated fish were not evaluated. However, given that bioaccumulation ofpropazine is expected to be low, ingestion of fish by piscivorus wildlife is not likelytobe of concern. $ Risks to top-level carnivores were not evaluated due to a lack ofdata for these receptors. Ingestion of grass, plants, hits,insects, and seedsby terrestrial wildlife was considered; however, consumption of small mammals and birds by carnivores was not evaluated. In addition, food chain exposures for aquatic receptors (i.e., fish consumption of aquatic invertebrates and/or aquatic plants) were also not considered. However, propazine's low 

### &, suggests that it is not likely to bioaccumulate. $ Fate studies indicate propazine ispersistent and mobile raising concerns about the impact on groundwater and surface water. The field dissipation studiesthat have been submitted are considered unacceptable or supplemental resulting in a significant uncertainty for this transport pathway. To address this uncertainty studies are needed to comprehensively ascertain themobility ofpropazine and its degradates under field conditions. $ No aerobic aquatic metabolism data is available for use in this assessment. An assumption was made that the aerobic aquatic metabolism half life istwice the aerobic soil metabolism half life. This represents an uncertainty in the assessment and additional data on the specific behavior ofpropazine in aerobic aquatic systems would be needed to eliminate this uncertainty.V. Literature Cited Brown, C.B., and J.L. White. 1969. Reactions of 1,2-s-triazineswith soil clays. Soil Sci. Soc. Am. Proc. 33:863-867. Burkhard, N., and J.A. Guth. 1981. Chemical hydrolysis of 

### 2-chloro-4,6-bis(alky1-amino)- 1,3,5-triazineherbicides and their breakdown under the influence 

### of adsorption. Pestic. Sci. 12:45-52. Harris, C.I. 1966. Adsorption, movement, and phytotoxicity ofmonuron and s-triazine herbicides in soils. Weeds 14:6-10. Hayes, M.H.B. 1970. Adsorption oftriazine herbicides on soil organic matter, including a short review of soil organic matter chemistry. Residue Rev. 3 1:13

### 1-1 74. Khan, Shahamat 

### U. 1980. Pesticides in the soil environment. Elsevier ScientificPublishing Company, Amsterdam. p. 90-97. Koskinen, W.C., and S.S. Harper. 1990. The retention process: mechanisms. 

### p. 51-77InH.H. Cheng (ed.) Pesticides in the soil environment: processes, impacts, and modeling. SSSA Book Series No. 2. Soil Science Society ofAmerica, Madison, WI. Montgomery, J.H. 1993. Agrochemicals desk reference: environmental data. Lewis Publishers, Chelsea, 

### MI. p. 356-358. Nearpass, D.C. 1972. Hydrolysis ofpropazine by the surface acidity of organicmatter. Soil Sci. Soc.Am. Proc. 36:606-610. Russell, J.D., M. Curz, and 

### J.L. White. 1968. Mode ofchemical degradation of s-triazines by montmorillonite. Science 160: 1340- 1342. Talbert, R.E., and O.H. Fletchall. 1965. The adsorption of some s-triazines in soils. Weeds 13:46-52. Walker, A., and D.V. Crawford. 1970. Diffusion coefficients for two triazine herbicides in six soils. Weed Res. 10: 126-132. Wolfe, N.L., U. Mingelgrin, and G.C. Miller. 1990. Abiotic transformations in water, sediments, and soil. p. 103-1 68In H.H. Cheng (ed.) Pesticides in the soil environment: processes, impacts, and modeling. SSSA Book Series No. 2. Soil Science Societyof America, Madison, WI. Worthing, C.R., ed. 1983. Thepesticide manual: A world compendium. Croydon, England: The British Crop Protection Council.Appendix A. Propazine 

### 4L Label

### AppendixB. 

### Environmental Fate StudiesHydrolysis (161-1, MRID 436898-02, Study Status: Acceptable). Ring-labeled ['4~]-propazine [6-chloro-N,N'-bis(1 -methylethyl)-

### l,3,5-triazine-2,4-diamine; radiochemical purity 98.4%, specific activity 104.4pCiImg] was added to aqueous buffered solutions ofpH 5 (0.1 

### M acetate), pH 7 (0.1 

### M phosphate), or pH 9 (0.01 

### M borate) at a concentration of 5 ppm. The [14~]-propazine stock solutions were prepared in toluene and added to autoclaved buffered solutions. Acetonitrile was added as a co-solvent at a concentration of 1

%. Aliquots ofthe solutions were radioassayed to confirm that the ['4~]-propazine was completely in solution. The sample flasks were incubated in the dark at 25

# +O°C. Triplicate samples were removed for analysis after 0, l,3,7, 14,21,and 30 days of incubation. Aliquots of the 0- and 30-day samples were tested for sterility using trypticase soy 

### and potato dextrose agar plates. Total recovered radioactivity ranged from 97.8 

### - 107.5% (mean 100.7

# +2.5%) for thepH 5 samples; 98.4 

### - 106.6% (mean 102.2

### 2 2.5%) for thepH 7 samples; and 96.9 - 106.4% (mean 102.3

## t2.7%) for the pH 9 samples. Propazine showed no evidence of decline in the pH 5,7, or 9 buffer solutions (Tables V-VII). At the end ofthe 30-day incubation period, recovered propazine levels comprised approximately 103% ofthe initial radioactivity in allbuffer solutions, with no degradates in excess of 1.5%ofthe applied. Theplot ofpropazine concentration with time showed no evidence of decline over the study. The slope was not significantly >O. While volatiles were not trapped, the material balances suggest that volatile losses were not significant. Results ofthe study indicate that hydrolysis is not a major avenue of environmental degadation for propazine.
Photodegradation in Water (161-2, MRIDs 001537-09,441848-05) MRID 441848-05 (Study Status:Acceptable) DER not available at date ofpublication 

### MRID 001 537-09 (Study Status: Supplemental) Propazine was photolytically stable in aqueous solutions (2.5 ppm propazine; further characterization not provided) when exposed to natural sunlight for up to 17days, less than the one-month time period specified for photolysis studies. In a second part ofthe study, propazine degraded under artificial light (sourcenot specified) with a half life of 24 hr. However, greater than 50% ofthe applied radioactivity was not accounted for in the material balance. These studies were considered supplemental and do not completely satisfy the environmental fate requirements for the aqueous photolysis of propazine.
Photodegradation on Soil (161-3, MRIDs 441848-06, Study Status: Acceptable) DER not available at date ofpublication
Photodegradation in Air (161-4) No Study Aerobic Soil Metabolism (162-1, MRIDs 441848-07 and 001537-12,MRID 441 848-07 DER not available at date ofpublication (Study Status: Acceptable)

MRID 001537- 12 (Study Status:Acceptable) Propazine, applied to a nonsterile loamy sand soil (9% clay, 86% sand; 2.2% organic 

### C; pH 5.6) at a rate of 10 ppm, degraded with a half-life of 12 to 24 weeks (calculated half-life was 15 weeks) under dark incubation at 25OC. The major degradate, hydroxy-propazine [2-hydroxy-4,6- bis(isopropy1amino)-s-triazine], comprised 14% ofthe applied radioactivity after 12 weeks and 3

### 1% after 52weeks. Unextractable residues accounted for an additional 35% at 12weeks and 58% after 52 weeks.
In sterilized loamy sand soil (method of sterilization was not indicated), propazine degraded with a half-life of 8 to 12weeks. Hydroxy-propazine comprised 16%ofthe applied radioactivity after 12 weeks while unextracted residues accounted for 3 1 %. The shorterhalf-life in the sterile soil may have resulted from alterations in soil properties due to sterilization or may indicate that factors other than microorganisms, such as surface catalysis, may play a role in the degradation ofpropazine.

Anaerobic Soil Metabolism (162-2, MRIDs 001537-13, Study Status: Acceptable) In an acceptable studypropazine degraded with a half-life of 8 weeks in a nonsterile loamy sand soil which was incubated anaerobically after 4 weeks of aerobic incubation. Propazine declined fi-om 77% to 36% ofthe applied after 8 weeks whilethe major degradate, hydroxy-propazine increased to 12%. Unextracted residues comprised 50% ofthe applied after 

### 8 weeks of anaerobic incubation. Anaerobic Aquatic Metabolism (162-3) No Study Aerobic Aquatic Metabolism (162-4) No Study Leaching 

### - Adsorption/Desorption (163-1, MRIDs 

### 001529-97,436898-03,496898-04, 442873-13) MRID 001529-97 (Study Status: Acceptable) DER not available at date ofpublication In that study, propazine was highly mobile, with Freundlich

### I& values for adsorption/desorption of 0.3416.09for loamy sand, 1.1413.78 for sandy loam, 2.69116.8 for loam, and 3.19/44.7 for clay loam. The adsorption 

### &, values were 65 for clay loam, 83 for loamy sand, 123 for sandy loam, and 158for loam. MRID 436898-03 (Study Status: Acceptable) The mobility ofpropazine andlor its degradates, applied at a rate of 5 ppm to four soils and aged for 30 days, varied with soil type and, possibly, column packing. An average of 2% (sandyloam) to 19% (sand) ofthe applied radioactivity was collected in the leachate. While the majority ofthe applied radioactivity remained in the 0-6 cm soil sections, ranging from 52% (loam) to 84% (sandy loam), radioactive residues were detected in each ofthe column sections, indicating 

### a redistribution ofthe aged propazine residues during the leaching process. Propazine was the only 14c-residueidentified in the leachate fractions and was the dominant residue in the 0-6 cm column sections. A supplemental study (MRID 001537-14) reviewed for the 1987

### EAB Science Chapter also found that the aged propazine residues were mobile (33% leached in sand soil) to slightly mobile (4%leached in loam soil). A second adsorptioddesorption study (MRID 001529-97) that was found acceptable in the 1987 EAB document also found that propazine was highly mobile. The Freundlich 

### IQvalues for adsorptionldesorption were 0.3416.09 for loamy sand, 1.1413.78for sandy loam, 2.69116.8 for loam, and 3.19144.7 for clay loam. The adsorption

## LC values were 65 for clay loam, 83 for loamy sand, 123 for sandy loam, and 158for loam.
In addition, that study found that the major degradate, hydroxy-propazine [2-hydroxy-4,6- 

### bis(isopropy1amino)-s-triazine], was less mobile than propazine. The Freundlich 

### Kd values for adsorptionldesorption of I.1313.42 for loamy sand, 2.9415.53 for sandy loam, 31.8156.8for loam, and 106/143for clay loam. The adsorption

### LC values were 276 for loamy sand, 359 for sandy loam, 187 1for loam, and 

### 2 163for clay loam. MRID 496898-04 (Study Status: Acceptable) Sand, sandy loam, loam, and silty clay soil samples were collected from the surface horizons of soils in Fayette and Madison Counties, 

### ICY. 

### A 24-hour equilibrationperiod was selected for the definitive study. The material balance for the individual replicationsin the definitive study ranged from 89.5 to 100.7%. The percentage of applied radioactivity adsorbed onthe soils decreased with increasing concentration ofpropazine in the aqueous solution, from 39.0% to 3 1.4% for the sandy loam sample, 4 1.O% to 34.8% for the sand, 39.4%to 32.6% for the loam, and 43.3% to 32.0% for the silty clay. Similarly, the percentage ofthe adsorbed radioactivity that was desorbed also decreased with increasing initial propazine concentration, from 32.6% to 26.9% for the sandy loam sample, 19.9% to 12.0% for the sand, 37.6%to 35.0% for the loam, and 35.8% to 26.8% for the silty clay. The Freundlich 

### Kd values for adsorptionldesorptionofpropazine were calculated to be 0.67186.4 for sand, 1.28111.9for sandy loam, 1.30127.0for silty clay, and 1.3516.7for loam. The adsorption 

### LC values, calculatedby the equation 

### (Kd /%organic 

### C) x 100, were 78.7 for the loam, 96.0 for the silty clay, 127.6 for the sandy loam, and 268.4 for the sand. The calculated 

### Kd and 

### LC values indicate that propazine is highly to moderately mobile in soils. Themajor degradate, hydroxy-propazine 

### [2-hydroxy-4,6-bis(isopropylamino)-s-trine], is less mobile than propazine, with Freundlich I& values for adsorptioddesorption of 1.1313.42for loamy sand, 2.9415.53 for sandy loam, 31.8156.8for loam, and 1061143for clay loam. The adsorption 

### I?, values were 276 for loamy sand, 359 for sandy loam, 1871 for loam, and 2163 for clay loam.MRID 442873- 1 3 (Study Status: Acceptable) Sandy loam was collected in Fayette County, while sand, loam, and silty clay soil samples were collected in Madison County, Kentucky. The overall material balance ofthe applied radioactivity was 98.4*0.7% (mean

# * % standard deviation).The material balance for the individual doses in the definitive studyranged from 92.7to 104.3%. As the concentration of 2- hydroxy-propazine in the aqueous solution increased, the percentage of applied radioactivity absorbed on each soil sample decreased during the adsorption phase: 41.69 to 34.75% for sandy loam, 44.83 to 36.60% for sand, 58.59 to 51.42% for loam, and 75.92 to 67.26% for silty clay. However, the trend of decreasing absorbed radioactivity with increasing solution concentration was not observed during the desorption phase. Instead, the desorbed radioactivity generally increased with increasing solution concentration in 

### 3 soils: 18.70 to 22.19% for sand, 16.26 to 22.19% for loam, and 12.00to 14.52%fro silty clay. No specific trend couldbe deciphered for sandy loam. The adsorption 

### Kd values of 2-hydroxy-propazine were calculatedtobe 1.447 for sandy loam, 0.823 for sand, 1.334for loam and 4.659 for silty clay. The desorption coefficients were 6.610 fro sandy loam, 4.167 for sand, 3.123 for loam, and 12.362fro silty clay. The adsorption and desorption coefficients were then normalized to organic carbon contentby multiplying &by (100% organic C) to yield 

### KO,. The adsorption

### I&,, values were 144.7 for sandy loam, 329.2 fro sand, 78.0 for loam and 342.6 for silty clay. Laboratory Volatilization (163-2) No Study Field Dissipation (164-1, MRIDs 442873-14,441848-09) MIRD 442873- 14 (Study Status: Supplemental) After application, propazine dissipated rapidly with two reported half-live: 7.2 days for a period of 1to 21 days and 58.2 days for a period of 28 to 184days. Residues of propazine were found in the 0-3,3-6, and 6-9 inch depths during the first 14days. After 21,28, and 90 days, propazine was detected in the 0-3 and 3-6 inch depths. After 90 days, residues ofpropazine were found only in the 0-3 in depth. The three degradates of propazine that were detected in the soil samples included 

### 2-amino-4-chloro-6-isopropylamino-s-train (DEA); 

### 2,4-diamino-6-chloro-s-triazine (DAA); and 

### 4,6-diissopropylamino-2-hydroxy-s-triazine or 2-hydroxyprpazine (OH-propazine). MRID 44 1848-09 (Study Status: Supplemental) The four submitted studies were either unacceptable or considered supplemental because of inadequate sampling depths (only the upper 12 inches were sampled), lack offreezer stability data (some samples were frozen for up to 3 years), and/or the presence ofpropazine in the control and treated plots prior to the start of the study. Supplemental data suggest that propazine, applied as a wettable powder at 2.4 to 4.8 lb a.i./A/yr, dissipated from the upper 

### 6 inches with a half-life of <30 to 149 days in 

### NY, <3 1 days in CA, and 60to >357 days in 

### NE. The degradates hydroxy-propazine, G-2873 [2-chloro-4,6-diamino-s-triazine], and G-30033 [2-chloro-4-amino6-isopropylamino-s-triazine] were detected in one or more ofthe field studies (NY, CA, NE). Aquatic Field Dissipation (164-2)No Study Small Scale Prospective Groundwater Monitoring (166-1) No Study

### Names and Chemical Structuresof Propazine and Major Transformation Products
Propazine (Propazine 4L) IUPAC Name: 

### 6-chloro-~',Af-di-iso~ro~~l-l,3,5 triazine-2,4-diamine CAS Name: 6-chloro-N,N1-bis(1 -methylethyl)-

### l,3,5-triazine-2,4-diamine CAS NO: 139-40-2

Propazine des-ethyl (G-30033) lUPAC name: NA CAS name: 2-amino-4-chloro-6-(1

### -methylethylamino)-s-triazine CAS No: NA

DACT (G-28273) IUPAC name: NA CAS name: 

### 2,4-diamino-6-chloro-s-triazine CAS No: NAPropazine 2-hydroxy or 2-hydroxypropazine (G-S

### 11526) IUPAC name: NA CAS name: 

### 2-hydroxy-4,6-bis-(l-methylethylamino)-s-triazine CAS No: NA

Desisopropyl hydroxypropazine IUPAC name: NA CASname: 

### 4-amino-2-hydroxy-6-isopropylaminotriazine CAS No: NA

Ammeline (GS-1 779

### 1) IUPAC name: NA CAS name: 

### 2,4-diamino-6-hydroxy-s-triazine CAS No: NA

### Triazine-methyl-triamine (CGA- 101 248) IUPAC name: NA CAS name: N-(1

### -methyl)-1,3,5-triazine-2,4,6-triamine CASNo: NA

Prometon (G-3 143 5) IUPAC name: NA CAS name: 2-methoxy-4,6-bis (1

### -methylethylamino)-s-triazine CAS No: NA



### Propazine-2-methyl-sulfinyl (GS-16141) IUPAC name: NA CAS name: 2,4-bis (1

### -methylethylamino)-6-methylsulfinyl-s-triazine CAS No: NA

### Appendix C. 

### Aquatic Exposure Model and Results (PRZMJEXAMS)Kansas Sorghum Crop Scenario Aerial Spray Application of Propazine4L stored as kssorpropaerial2.out Chemical: Propazine PRZM environment: KSsorghumC.txt modified Satday, 12 October 2002 at 15 :57 :00 EXAMS environment: pond298.exv modified Thuday, 24 July 2003 at 10:02:00 Metfile: w13996.dvf modified Wedday, 3 July 2002 at 09:04:44 Water segment concentrations (ppb)
Year 1961 1962 1963 1964 1965 1966 1967 196 8 1969 1970 197 1 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 Peak 96 hr 21 Day 60 Day 90 Day Yearly 9.051 9.009 8.844 8.727 8.589 5.038 22.23 22.12 21.91 21.29 20.77 14.43 22.47 22.41 22.25 21.79 21.39 18.65 24.63 24.56 24.31 23.69 23.23 19.99 27.32 27.26 27.01 26.47 25.96 22.38 29.18 29.13 28.79 27.98 27.4 24.04 34.22 34.12 33.73 33.06 32.44 27.52 32.13 32.04 31.79 31.23 30.83 28.39 34.3 34.21 34 33.22 32.55 28.88 37.24 37.16 36.92 36.35 35.71 30.96 47.89 47.76 47.23 46.42 45.55 37.28 39.22 39.12 38.71 38.66 38.51 36.41 42.67 42.58 42.06 41.13 40.47 35.83 41.02 40.92 40.5 40.15 39.49 35.55 37.35 37.28 37.17 36.54 35.95 33.08 36.22 36.13 35.77 35.01 34.47 31.12 45.24 45.08 44.76 44.07 43.18 35.54 49.66 49.49 49 48.3 47.37 40.48 41.99 41.9 41.52 41.13 40.84 38.55 44.19 44.06 43.49 42.34 41.4 36.65 48.64 48.5 47.98 46.92 45.95 39.23 52.96 52.89 52.54 51.41 50.42 43.31 48.18 48.1 47.84 46.96 46.08 41.81 49.54 49.41 48.91 48.09 47.18 41.18 46.55 46.43 45.98 45.19 44.6 40.65 51.83 51.69 51.13 49.91 49 42 -28 47.42 47.28 46.86 46.28 45.45 41.41 46.01 45.87 45.38 44.3 44.1 40.12 42.15 42.06 41.67 41.33 40.85 37.89 50.26 50.12 49.56 48.43 47.47 40.3 Sorted results Prob. Peak 96 hr 21 Day 60 Day 90 Day Yearly 0.032258064516129 52.96 52.89 52.54 51.41 50.42 43.31 0.0645161290322581 51.83 51.69 51.13 49.91 49 42.28 0.0967741935483871 50.26 50.12 49.56 48.43 47.47 41.81 0.129032258064516 49.66 49.49 49 48.3 47.37 41.41 0.161290322580645 49.54 49.41 48.91 48.09 47.18 41.18 0.193548387096774 48.64 48.5 47.98 46.96 46.08 40.65 0.225806451612903 48.18 48.1 47.84 46.92 45.95 40.48 0.258064516129032 47.89 47.76 47.23 46.42 45.55 40.3 0.290322580645161 47.42 47.28 46.86 46.28 45.45 40.12 0.32258064516129 46.55 46.43 45.98 45.19 44.6 39.23 0.354838709677419 46.01 45.87 45.38 44.3 44.1 38.55 0.387096774193548 45.24 45.08 44.76 44.07 43.18 37.890.1 50.2 50.057 49.504 48.417 47.46 41.77 Average of yearly averages: 32.9649333333333 Inputs generated by pe4.pl - 8-August-2003 Data used for this run: Output File: kssorpropaerial2 Metfile: w13996.dvf PRZM scenario: KSsorghumC.txt EXAMS environment file: pond298.exv Chemical Name: Propazine Description Variable Name Value Units Comments Molecular weight mwt 230 g/mol Henry's Law Const. henry 1.02e-9 atm-mA3/mol Vapor Pressure vapr 2.9e-8 torr Solubility sol 8.6 mg/L K d Kd mg/L Koc Koc 125 mg/L Photolysis half-life kdp 0 days Half-life Aerobic Aquatic Metabolism kbacw 960 days Halfife Anaerobic Aquatic Metabolism kbacs 112 days Halfife Aerobic Soil Metabolism asm 480 days Halfife Hydrolysis: pH 7 0 days Half-life Method : CAM 2 integer See PRZM manual Incorporation Depth: DEPI 0 cm Application Rate: TAPP 1.344 kg/ha Application Efficiency: APPEFF .95 fraction Spray Drift DRFT .05 fraction of application rate applied to pond Application Date Date 10-5 dd/mrn or dd/rnrnrn or dd-mm or dd-mmm Record 17: FILTRA IPSCND UPTKF Record 18: PLVKRT PLDKRT FEXTRC 0.5 Flag for Index Res. Run IR Pond Flag for runoff calc. RUNOFF none none, monthly or total(average of entire run)Kansas Sorghum Crop Scenario Ground Spray ApplicationofPropazine4L stored as kssorpropground.out Chemical: Propazine PRZM environment: KSsorghumC.txt modified Satday, 12 October 2002 at 15:57:00 EXAMS environment: pond298.exv modified Thuday, 24 July 2003 at 10:02:00 Metfile: w13996.dvf modified Wedday, 3 July 2002 at 09:04:44 Water segment concentrations (ppb)
Year 1961 1962 1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 Peak 96 hr 21 Day 60 Day 90 Day Yearly 6.834 6.801 6.673 6.533 6.46 3.758 18.62 18.53 18.34 17.83 17.4 11.75 17.33 17.29 17.18 16.88 16.6 14.84 18.9 18.84 18.65 18.14 17.77 15.3 20.79 20.75 20.58 20.12 19.75 17 22.17 22.13 21.87 21.21 20.78 18.12 26.92 26.84 26.52 25.93 25.45 21.23 24.29 24.23 24.01 23.55 23.24 21.69 26.26 26.2 26.02 25.43 24.92 21.9 28.93 28.87 28.64 28.15 27.68 23.9 39.79 39.67 39.21 38.5 37.78 30.38 31.08 31.05 30.94 30.71 30.52 29.39 34.28 34.21 33.78 33.02 32.49 28.65 32.41 32.33 32.01 31.77 31.28 28.33 28.72 28.67 28.52 28.05 27.57 25.71 27.34 27.28 27.01 26.43 26.01 23.66 36.84 36.71 36.38 35.9 35.19 28.29 41.59 41.5 40.96 40.48 39.71 33.47 33.66 33.63 33.51 33.26 33.07 31.4 35.68 35.58 35.11 34.13 33.4 29.47 40.39 40.27 39.83 38.99 38.19 32.27 44.76 44.69 44.42 43.47 42.64 36.42 39.71 39.64 39.38 38.73 38.01 34.8 41.32 41.21 40.79 40.2 39.46 34.2 38.31 38.21 37.84 37 36.59 33.61 43.51 43.39 42.91 41.87 41.11 35.3 39.34 39.23 38.91 38.37 37.7 34.44 38.14 38.03 37.62 36.58 36.22 33.13 33.71 33.63 33.37 33.1 32.8 30.79 41.82 41.7 41.22 40.31 39.52 33.2 Sorted results Prob. Peak 96 hr 21 Day 60 Day 90 Day Yearly 0.032258064516129 44.76 44.69 44.42 43.47 42.64 36.42 0.0645161290322581 43.51 43.39 42.91 41.87 41.11 35.3 0.0967741935483871 41.82 41.7 41.22 40.48 39.71 34.8 0.129032258064516 41.59 41.5 40.96 40.31 39.52 34.44 0.161290322580645 41.32 41.21 40.79 40.2 39.46 34.2 0.193548387096774 40.39 40.27 39.83 38.99 38.19 33.61 0.225806451612903 39.79 39.67 39.38 38.73 38.01 33.47 0.258064516129032 39.71 39.64 39.21 38.5 37.78 33.2 0.290322580645161 39.34 39.23 38.91 38.37 37.7 33.13 0.32258064516129 38.31 38.21 37.84 37 36.59 32.27 0.354838709677419 38.14 38.03 37.62 36.58 36.22 31.4 0.387096774193548 36.84 36.71 36.38 35.9 35.19 30.790.1 41.797 41.68 41.194 40.463 39.691 34.764 Average of yearly averages: 26.5466 Inputs generated by pe4.pl - 8-August-2003 Data used for this run: Output File: kssorpropground Metf ile: w13996.dvf PRZM scenario: KSsorghumC.txt EXAMS environment file: pond298.exv Chemical Name: Propazine Description Variable Name Value Units Comments Molecular weight mwt 230 g/mol Henry's Law Const. henry 1.02e-9 atm-mA3/mol Vapor Pressure vapr 2.9e-8 torr Solubility sol 8.6 mg/L Kd Kd mg/L Koc Koc 125 mg/L Photolysis half-life kdp 0 days Half-life Aerobic Aquatic Metabolism kbacw 960 days Halfife Anaerobic Aquatic Metabolism kbacs 112 days Halfife Aerobic Soil Metabolism asm 480 days Halfife Hydrolysis: pH 7 0 days Half-life Method: CAM 2 integer See PRZM manual Incorporation Depth: DEPI 0 cm Application Rate: TAPP 1.344 kg/ha Application Efficiency: APPEFF .99 fraction Spray Drift DRFT .01 fraction of application rate applied to pond Application Date Date 10-5 dd/mm or dd/mmm or dd-mm or dd-mmrn Record 17: FILTRA IPSCND UPTKF Record 18: PLVKRT PLDKRT FEXTRC 0.5 Flag for Index Res. Run IR Pond Flag for runoff calc. RUNOFF none none, monthly or total(average of entire run)Texas Sorghum Crop Scenario Aerial Spray Application of Propazine4L stored as txsorpropaerial.out Chemical: Propazine PRZM environment: TXsorghumC.txt modified Satday, 12 October 2002 at 17:29:00 EXAMS environment: pond298.exv modified Thuday, 24 July 2003 at 10:02:00 Metfile: w13958.dvf modified Wedday, 3 July 2002 at 09:06:24 Water segment concentrations (ppb)
Year 196 1 1962 1963 1964 196 5 196 6 1967 196 8 1969 1970 1971 1972 1973 1974 1975 1976 197 7 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 Peak 96 hr 21 Day 60 Day 90 Day Yearly 6.805 6.776 6.686 6.45 6.336 3.85 14.84 14.77 14.52 13.96 13.56 9.491 13.18 13.13 12.95 12.82 12.59 10.92 14.31 14.25 14.04 13.76 13.53 11.19 41.58 41.47 40.74 39.36 38.26 25.68 42.1 41.95 41.4 40.15 39.25 32.82 33.32 33.22 32.9 31.96 31.49 28.69 48.06 47.87 47.2 45.62 44.54 34.66 46.82 46.66 46.12 44.74 43.63 37.11 58.2 57.98 57.22 55.34 53.91 42.69 41.95 41.89 41.63 41.07 40.64 37.22 104 104 103 99.16 96.42 67.01 73.09 73 72.63 71.83 71.15 64.45 78.86 78.56 77.35 74.79 73 60.98 60.18 60.06 59.55 58.22 57.16 52.88 64.81 64.59 64.07 62.23 60.8 50.92 48.08 48.02 47.81 47.31 46.87 42.93 70.02 69.73 68.98 67.01 65.27 50.04 87.73 87.42 86.11 83.21 81.12 65.28 72.42 72.24 71.72 69.67 67.97 61.1 58.54 58.37 57.93 57.09 55.98 50.13 60.96 60.74 59.87 57.91 56.39 47.31 71.54 71.26 70.52 68.36 66.68 53.51 51.79 51.72 51.46 50.87 50.36 45.48 37.53 37.43 37.05 36.64 36.28 33.21 103 102 101 96.86 94.4 64.85 73.35 73.16 72.45 71 69.64 64.61 54.95 54.81 54.25 53.33 52.54 48.76 64.51 64.34 63.56 61.65 60.19 48.69 80.04 79.7 78.38 75.61 73.56 58.22
Sorted results Prob. Peak 96 hr 21 Day 60 Day 90 Day Yearly 0.032258064516129 104 104 103 99.16 96.42 67.01 0.0645161290322581 103 102 101 96.8694.4 65.28 0.0967741935483871 87.73 87.42 86.11 83.21 81.12 64.85 0.129032258064516 80.04 79.7 78.38 75.61 73.56 64.61 0.161290322580645 78.86 78.56 77.35 74.79 73 64.45 0.193548387096774 73.35 73.16 72.63 71.83 71.15 61.1 0.225806451612903 73.09 73 72.45 71 69.64 60.98 0.258064516129032 72.42 72.24 71.72 69.67 67.97 58.22 0.290322580645161 71.54 71.26 70.52 68.36 66.68 53.51 0.32258064516129 70.02 69.73 68.98 67.01 65.27 52.88 0.354838709677419 64.81 64.59 64.07 62.23 60.8 50.92 0.387096774193548 64.51 64.34 63.56 61.65 60.19 50.130.1 86.961 86.648 85.337 82.45 80.364 64.826 Average of yearly averages: 43.4893666666667 Inputs generated by pe4.pl - 8-August-2003 Data used for this run: Output File: txsorpropaerial Metf ile: w13958.dvf PRZM scenario: TXsorghumC.txt EXAMS environment file: pond298.exv Chemical Name: Propazine Description Variable Name Value Units Comments Molecular weight mwt 230 g/mol Henry's Law Const. henry 1.02e-9 atm-mA3/mol Vapor Pressure vapr 2.9e-8 torr Solubility sol 8.6 mg/L Kd Kd mg/L Koc Koc 125 mg/L Photolysis half-life kdp 0 days Half-life Aerobic Aquatic Metabolism kbacw 960 days Halfife Anaerobic Aquatic Metabolism kbacs 112 days Halfife Aerobic Soil Metabolism asm 480 days Halfife Hydrolysis: pH 7 0 days Half-life Method : CAM 2 integer See PRZM manual Incorporation Depth: DEPI 0 cm Application Rate: TAPP 1.344 kg/ha Application Efficiency: APPEFF .95 fraction Spray Drift DRFT .05 fraction of application rate applied to pond Application Date Date 01-5 dd/rnrn or dd/mrnrn or dd-rnrn or dd-mmm Record 17: FILTRA IPSCND UPTKF Record 18: PLVKRT PLDKRT FEXTRC 0.5 Flag for Index Res. Run IR Pond Flag for runoff calc. RUNOFF none none, monthly or total(average of entire run)Texas Sorghum Crop Scenario Ground Spray Application of Propazine4L stored as txsorpropground.out Chemical: Propazine PRZM environment: TXsorghumC.txt modified Satday, 12 October 2002 at 17 :29 :00 EXAMS environment: pond298.exv modified Thuday, 24 July 2003 at 10:02:00 Metfile: w13958.dvf modified Wedday, 3 July 2002 at 09:06:24 Water segment concentrations (ppb)
Year 196 1 1962 1963 1964 1965 196 6 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 198 6 1987 1988 1989 1990 Peak 96 hr 21 Day 60 Day 90 Day Yearly 4.561 4.542 4.481 4.321 4.204 2.516 11.21 11.15 10.96 10.51 10.2 6.823 8.273 8.249 8.147 8.009 7.917 7.313 8.535 8.504 8.379 8.306 8.227 6.94 36.61 36.5 35.83 34.55 33.56 21.51 36.6 36.47 35.99 34.9 34.1 28.58 27.42 27.34 27.11 26.31 25.83 24.07 42.44 42.26 41.66 40.24 39.22 30.07 40.92 40.78 40.32 39.12 38.16 32.48 52.81 52.6 51.91 50.18 48.87 38.22 37.99 37.93 37.7 37.19 36.8 32.52 101 100 99.43 95.79 93.11 63.63 70.49 70.41 70.05 69.28 68.62 60.86 74.22 73.94 72.8 70.38 68.63 57.22 54.7 54.58 54.15 52.98 52.34 48.69 59.49 59.29 58.79 57.11 55.79 46.6 44.11 44.06 43.86 43.4 43 38.21 64.87 64.6 63.83 62.03 60.41 45.75 83.5 83.2 81.94 79.15 77.15 61.6 67.4 67.24 66.75 64.86 63.27 57.29 53.13 52.98 52.63 51.82 50.84 45.95 55.68 55.47 54.68 52.88 51.49 43.09 66.68 66.42 65.76 63.74 62.16 49.52 48.24 48.18 47.94 47.38 46.91 41.14 33.21 33.17 33 32.62 32.31 28.39 99.16 98.67 97.29 93.49 91.01 61.42 68.84 68.75 68.36 67.5 66.84 61.14 50.67 50.6 50.33 49.74 49.26 44.6 59.46 59.31 58.57 56.76 55.43 44.59 75.53 75.21 73.95 71.33 69.39 54.57
Sorted results Prob. Peak 96 hr 21 Day 60 Day 90 Day Year1 y 0.032258064516129 101 100 99.43 95.79 93.11 63.63 0.0645161290322581 99.16 98.67 97.29 93.49 91.01 61.6 0.0967741935483871 83.5 83.2 81.94 79.15 77.15 61.42 0.129032258064516 75.53 75.21 73.95 71.33 69.39 61.14 0.161290322580645 74.22 73.94 72.8 70.38 68.63 60.86 0.193548387096774 70.49 70.41 70.05 69.28 68.62 57.29 0.225806451612903 68.84 68.75 68.36 67.5 66.84 57.22 0.258064516129032 67.4 67.24 66.75 64.86 63.27 54.57 0.290322580645161 66.68 66.42 65.76 63.74 62.16 49.52 0.32258064516129 64.87 64.6 63.83 62.03 60.41 48.69 0.354838709677419 59.49 59.31 58.79 57.11 55.79 46.6 0.387096774193548 59.46 59.29 58.57 56.76 55.43 45.950.1 82.703 82.401 81.141 78.368 76.374 61.392 Average of yearly averages: 39.5100666666667 Inputs generated by pe4.pl - 8-August-2003 Data used for this run: Output File: txsorpropground Metf ile: w13958.dvf PRZM scenario: TXsorghumC.txt EXAMS environment file: pond298.exv Chemical Name: Propazine Description Variable Name Value Units Comments Molecular weight mwt 230 g/mol Henry's Law Const. henry 1.02e-9 atm-mA3/mol Vapor Pressure vapr 2.9e-8 torr Solubility sol 8.6 mg/L Kd Kd mg/L Koc Koc 125 mg/L Photolysis half-life kdp 0 days Half-life Aerobic Aquatic Metabolism kbacw 960 days Halfife Anaerobic Aquatic Metabolism kbacs 112 days Halfife Aerobic Soil Metabolism asm 480 days Halfife Hydrolysis: pH 7 0 days Half-life Method : CAM 2 integer See PRZM manual Incorporation Depth: DEPI 0 cm Application Rate: TAPP 1.344 kg/ha Application Efficiency: APPEFF .99 fraction Spray Drift DRFT .01 fraction of application rate applied to pond Application Date Date 01-5 dd/mm or dd/mmrn or dd-mm or dd-rnmm Record 17: FILTRA IPSCND UPTKF Record 18: PLVKRT PLDKRT FEXTRC 0.5 Flag for Index Res. Run IR Pond Flag for runoff calc. RUNOFF none none, monthly or total(average of entire run)Appendix 

### D. 

### T-REX Model and Results

### Upper Bound Kenaga Residues For RQ 

### Calculation

EndpointsAppendix 

### E. TerrPlant Model and ResultsTerrestrial Plant EECs and Acute Non Endangered RQs (November9, 2005; version 1.2.1) Input Values a.iJacre)
RunoffValue (0.01,0.02, or 0.05 if chemicat solubility el

0,lO-100, or >I00 ppm, respectively)

Minimum 

# l----L4

IncorporationDepth (inches)
Seed Emerg MonocotEC25 (Ib a.i Jacre) Seed Emerg Dicot EC25 (N,a.i.lacre)

Veg Vigor Monocot EC25 (Ib a.iJacre) Chemical: Propazine4L



### - Estimated Environmental Concentrations(EECs) for

NON-GRANULAR formulation applications (Ibs a.i./acre)

0.035

0.016

0.046 Application Method

Ground Unincorp. Ground lncorp Risk Quotients (RQs)for NON-GRANULARformulation applications

Airblast, Chemigation Total Loading to Adjacent Areas (EEC = Sheet Runoff +Drift)

0.0240
0.0240 Total LoadingtoSemiaquatic Areas (EEC 

### - Channelized Runoff

### + Drift)

0.1 320
0.1 320 Drift RQs RQ = Drift EEC/Most Sensitive EC25 Emergence RQs, Adjacent Areas RQ = EECISeedling Emergence EC25 DRIFT EEC (for ground: application ratex 0.01) (for aerial: application ratex 0.05)

0.0120
0.0120 Monocot 0.34
0.34 Emergence RQs, Semi-aquatic Areas RQ = EECISeedling Emergence EC25

Monocot 0.69
0.69 Dicot 0.75
0.75 Monocot 3.77
3.77 Dicot 1.50
1.50 Dicot 8.25
8.25Terrestrial Plant EECsand Acute Non Endangered RQs (November 9,2005;version 1.2.1) Input Values Chemical: Propazine4LMinimum Incorporation (inches) Terrestrial Plant EECs and Acute Endangered RQs (November 9, 2005; version 1.2.1) Input Values

Seed Emerg c0.01 Monocot EC05or NOAEC (Ib 

# 1 Application Rate (Ib a.i.lacre) RunoffValue (0.01,0.02, or 0.05 if chemical solubility 40, 10-100, or >I00ppm, respectively)

a.i.1acre) Dicot ECOS 1.2

0.01

Veg Vigor Monocot EC05 or NOAEC (Ibs Chemical: Propazine4L

Estimated Environmental Concentrations (EECs)for NON-GRANULARformulation applications (lbs a.iJacre) Application Method

Ground Unincorp. Ground lncorp

Aerial, Airblast, spray Chemigation Risk Quotients (RQs) for NON-GRANULAR formulation applications
Total Loading to Adjacent Areas (EEC = Sheet Runoff

### + Drift)

0.0240
0.0240

0.0720 Emergence RQs, AdjacentAreas RQ = EEClSeedling Emergence EC05 or NOAEC Total Loadingto Semi-aquatic Areas (EEC = (Channelized Runoff

### + Drift)

0.1 320
0.1320

0.1 800 Monocot
>2.40
~2.40

>7.20 DRIFT EEC (for ground: application ratex 0.01) (for aerial: application ratex 0.05)

0.01 20
0.0120

0.0600 Dicot
5.1 1
5.1 1

15.32 Emergence RQs, Semiaquatic areas RQ = EECISeedling Emergence EC05 or NOAEC

Monocot
>13.20
13.20

>18.00 Drift RQs RQ = EECIMost Sensitive EC05 or NOAEC

Dicot
28.09
28.09

38.30 Monocot
>1.20
>1.20

>6.W Dicot
2.55
2.55

12.77

### Appendix 

### F. Ecological 

### Effects Data

### 71-1 Avian Acute Oral Bobwhite Quail. MRID 442873-01 (Core). Propazine was tested in a single oral gavage study with bobwhite quail (5lsexldose at nominal concentrations of 0, 0 (vehicle control), 260,430, 720, 1200or 2000 mg/kg bw with a 14-day observation period). Propazine was determined to be slightly toxic to bobwhite quail with an LD50of>1,640 mg ailkg, the highest dose tested when corrected for % active ingredient. At the 1200mg/kg dose level, only 4 females were tested. Transient decreases in body weight and food consumption were observed at 430 mag bw and above. TheNOAEL was determined to be 244 mg ailkg due to weight loss up to 72 hours after treatment. The study is scientifically sound and fulfills the guideline requirements. 

### 71-2 Avian Subacute Dietary Bobwhite Quail. MRID 442873-02 (Core). In an 8-day dietary study, propazine was determined to be slightly toxic to bobwhite quail with an LC5() >4,930 ppm ai (nominal concentration). A NOAEL was not determined. Diminished feed consumption, slow growth, and cannibalism is attributed to a possible chemical-induced anorexia. The study is scientifically sound and fulfills guidelinerequirements. Mallard. MRID 442873-03 (Core). In an 8-day dietary study, propazine was determined to be practically non-toxic to mallard ducklings with an LCs0>5,140 ppm ai (nominal concentration). A NOAEL was not determined. Feed consumption rates and resultant growth indicated a chemically-induced anorexia. The study is scientifically sound and fulfills guideline requirements. 

### 72-1 Freshwater Fish Acute Bluegill Sunfish. MRID 442873-04 (Invalid). In a 96-hour flow-through test, thereported LCs0 and NOAEL of>4.5 mg ai/L may overestimate the toxicity due to the limited solubility of propazine. Precipitate in the higher treatment levels raises a question of actual exposure and bioavailability. Erratic swimming behavior in fish treated with 1.0and 1.8mg/L ofpropazine may represent a compound-related affect in treatments where propazine was freely soluble. The study is not scientifically sound and does not meet guideline requirements. 

### 72-2 Freshwater Invertebrate Acute Daphnia. MRID 442873-05 (Uncertain). In a 48-hour flow-through test, propazine was determined tobe moderately toxic to daphnids with an ECsoof >5.32 ppm ai (mean measured concentration). TheNOAEC was determined to be 5.32 ppm ai. The studyis scientifically sound but does not fulfill guideline requirements because daphnids were not exposed up to 100 ppm ai. If it can be shown that the test was conducted up to the limit of solubility, the study may be upgraded to acceptable. This study was originally classified as supplemental; however, it was reevaluated in 2005 and is awaiting EFED validation. 

### 72-3b EstuarineIMarine Invertebrate Acute Eastern Oyster. MRID 442873-06 (Uncertain). In a 96-hour flow-through test, propazine was determined to be practically non-toxic to the eastern oyster at the limit ofwater solubility with an EC50of >3.72 mg ai/L (mean measured concentration). The NOAEC was determined to be 3.72 mg ai/L. No significant adverse effects were observed on shell deposition. The study isscientifically sound and fulfills guideline requirements. This studywas originally classified as invalid due to limited solubility ofpropazine; however, it was reevaluated in 2006 and EFED established the reported values (classification awaiting EFED validation). SaltwaterMysid. MRID 441 848-01 (Acceptable). In a 96-hour static test, propazine was determined to be moderately toxic to saltwater mysid with 

### an of 4.20ppm ai (mean measured concentration), based on mortality and sublethal effects. TheNOAEC was determined to be 0.586ppm ai. The study is scientifically sound and fulfills guideline requirements. 72-4a Freshwater Fish Early Life Stage Fathead Minnow. MRID 442873-07 (Supplemental). In an early life-stage flow-through test, propazine produced significant reduction in length. The NOAEL was determined to be 0.72 mg ai/L). TheMATC was calculated at 0.938 mg ai/L. The study is scientifically sound, but does not fulfill guideline requirements since both pH and hardness exceeded recommended levels potentially affecting solubility. 72-4b Freshwater Invertebrate Life Cycle Daphnia. MRID 443276-02 (Core). In a life cycle flow-through test, the NOAEC and LOAEC were determined to be 0.047ppm ai mg/L and 0.091 ppm ai,respectively, based on growth measured in terms oflength (mm) and weight (g). The studyis scientifically sound and fulfills guidelinerequirements. 72-4c EstuarineIMarine Fish Life Cycle Sheepshead Minnow. MRID 441 848-02 (Uncertain). In a 36-day chronic flow-through test, propazine was determined to affect embryo survival and hatching success in early life-stage sheepshead minnow with an NOAEC of 1.34 mg ai/L (mean measured concentration). The LOAEC was determined to be 2.59 mg ai/L. The studyis scientifically sound and meets guideline protocols. This studywas reevaluated in 2006 and EFED disagreed with the study author's conclusion and modified the results (classification awaiting EFED validation). 72-4d EstuarineIMarine Invertebrate Life Cycle SaltwaterMysid. MRID 441 848-03 (Supplemental). In a 28-day life cycle test under flowthrough conditions, propazine produced significant effects on growth (dry weight, combined and separate sexes) and reproduction. The NOAEC and LOAEC were 0.269 and 0.706 ppm ai (mean measured concentrations), respectively. The study is scientifically sound; however, since second-generation mysids were not maintained for at least 4 days and observed for survival, development and behavior, the study does not fulfill guideline requirements.

81-1 Acute Mammalian Oral Rat. MRID 434741-01 (Core). In an acute oral study, propazine was determined to have be practically non-toxic (Toxicity Category IV) to rats with an LDS0 of >5050 mglkg. The study is scientifically sound and fulfills guideline requirements. 83-3 Mammalian DevelopmentalRat. MRID 001 502-42 (Core). In a developmental toxicity studywith Sprague-Dawley rats, propazine produced maternal and developmental toxicity. The maternal NOAEL was 10 mglkglday (LOAEL = 100mglkglday) based upon decreased body weights and food consumption. Salivation was also reported at doses 2500 mgkglday. The developmental NOAEL was 10mgkglday (LOAEL = 100mgkglday) based on decreased ossification. This study is scientifically sound and fulfills guideline requirements. Rabbit. MRID 441534-01 (Core). In a developmental toxicity studywith New Zealand White rabbits, propazine produced maternal toxicity. No developmental toxicity was observed. The maternal NOAEL was 10mgkglday (LOAEL =50mgkglday) based upon decreased defecation and decreased body weight gain and food consumption. This studyis scientifically sound and fulfills guidelinerequirements. 83-4 Mammalian Reproduction Rat. MRID 0004141-09 (Core). In a 3 -generation reproduction study, propazine produced parentalloffspring toxicity with a NOAEL of 5mgfkglday(100ppm) and the LOAEL of 50 mglkglday 

### (1000 ppm) based upon body weight decrements in males and females. No reproductivetoxicity was observed; consequently, theNOAEL was 250mgkglday (21000ppm) and the LOAEL was >50 mglkglday (>1000 pprn). This study is scientifically sound and fulfills guidelinerequirements. 122-2 Aquatic Plant Algae Blue-green algae. MRID 442873-12 (Core). In a Tier I1 toxicity test with AnabaenaJlos-aquae, the 7 dayECsofor cell densitywas 0.18 pprn ai (NOAEC =0.068 pprn ai). The studyis scientifically sound and fulfills the guideline requirements. Green algae. MRID 442873-08 (Core). In a Tier I1 toxicity test with Selenastrum capricornutum, the 7 day ECsofor cell density was 0.029pprn ai (NOAEC =0.012 pprn ai). The study is scientifically sound and hlfills the guideline requirements. Marine diatom. MRID 442873-1 1 (Core). In a Tier I1 toxicity test with Skeletonemacostatum, the 7 day ECSO for cell density was 0.025 pprn ai (NOAEC =0.01 7 pprn ai). The study is scientifically sound and fulfills the guideline requirements. Diatom. MRID 442873-10 (Core). In a Tier I1 toxicity test with Naviculapelliculosa,the 7 day ECS0for cell density was 0.0248 pprn ai (NOAEC =0.0065 pprn ai). The studyis scientifically sound and hlfills the guideline requirements. 123-l(a) Seedling Emergence

## - Tier 

### I1 Monocots (5 species) and Dicots (6 species). MRID 441 848-04 (Uncertain). In a Tier I1 seedling emergence study, percent emergence, shoot weight and shoot length were affected in all species tested (cabbage, corn, cucumber, lettuce, oats, onion, ryegrass, radish, soybean, tomato and wheat) with shoot weightbeing the most sensitive parameter tested. Onion was the most sensitivemonocot species (EC2S0.035 lb ailA, NOAEC <0.010 lb ai/A) and lettuce was the most sensitive dicot species (EC2S0.016 lb ai/A,NOAEC <0.0047 lb ai/A). With the exception of corn and ryegrass, all species exhibited phytotoxic effects, including chlorosis, necrosis, stuntingand mortalities. This studywas reevaluated in 2006 and additional statistical analyses were performed (classification awaiting EFED validation). 123-l(b) Vegetative Vigor 

### - Tier I1
Monocots 

### (5 species) and Dicots (6 species). MRID 441 848-04 (Uncertain). In a Tier I1 vegetative vigor study, shoot weight and shoot height were affected in all species tested (cabbage, cucumber, lettuce, oats, onion, ryegrass, radish, soybean, tomato and wheat), with the exception of corn. Shoot weight was themost sensitive parameter tested with wheat being the most sensitivemonocot species (EC25 0.046 lb ai/A,NOAEC C0.020 lb ai/A). Cucumber was the most sensitive dicot species (EC250.010 lb ai/A, NOAEC ~0.075 lb ai/A). With the exception oftomato and soybean, all species exhibited phytotoxic effects, including chlorosis, necrosis, stunting and mortalities. This studywas reevaluated in 2006 and additional statistical analyses were performed (classification awaiting EFED validation). 123-2 Aquatic Plant Acute Duckweed. MRID 442873-09 (Core). In a Tier I1 toxicity test with

### Lemna gibba, the 7 day EC50 for cell density was 0.10ppm ai (NOAEC = 0.022 ppm ai). The study is scientifically sound and fulfillsthe guidelinerequirements. 141-1 Acute Contact Toxicity Test to Honey Bees In an acute contact study with the honey bee, propazine was determined to be relatively nontoxic. At 96 hours, mortality was 2.47% at a dose of 96.69 pg/bee (Atkins et al. 1975). A belljar vacuum duster was used to apply the pesticide, mixed with a pyrolite dust diluent and given to the test bees. Dosages ofthe dust were weighed, bees were aspirated into dusting cages and treated, and then bees were transferred into holding cages. Observations were recorded at 12,24, 48, 72 and 96 hours. The studywas scientifically sound and showed that propazine is relatively non-toxic to honey bees. The study fulfills the guideline requirement for an acute contact toxicity test on honey bees.Appendix 

### G. The Risk Quotient Method and Levels of ConcernThe risks to terrestrial and aquatic organisms are determined based on a method by which risk quotients (RQs) are compared with levels ofconcern (LOCs). This method provides an indication of a chemical's potential to cause an effect in the field from effects observed in laboratory studies, when used as directed. Risk quotients are expressed as theratio ofthe estimated environmental concentration (EEC) to the species-specific toxicity reference value (TRV): 

# EEC RQ= - 

# TRV Units for EEC and TRV should be the same (e.g., pg1L or ppb). The RQ is compared to the LOC as part of a risk characterization. Acute and chronic LOCs for terrestrial and aquatic organisms are given in recent Agency guidance (EPA, 2004) and summarized in the table below.

Level of concern (LOC) by risk presumption category (U.S. EPA 2004). Risk Presumption RQ LOC

Acute Risk a Acute Restricted Use" Acute Endangered Species

## ' Chronic Risk

Acute Risk Acute Restricted Use Acute Endangered Species Chronic Risk

Acute Risk Acute Endangered Species
Acute Risk Acute Endangered Species Mammals and Birds EEC~ILC~~ or LDSO/sqftc or LDsdday EECILCSO or LDsOlsqft or LDSdday(or LDso40 mglkg) EEC/LCSO or LDS0/sqft orLDsdday EEC/NOAEC Aquatic Animals EECYLCSO or ECsO EEC/LCSo or ECso EEC/LCSo or ECsO EECrnOAEC Terrestrial and Semi-aquatic Plants EECIEC25 EEC/ECosor NOAEC Aquatic Plants EEC~IEC~~ EECYECOs or NOAEC 'Potential for acutetoxicity for receptor species if RQ > LOC (EPA, 2004). h~sti~nated nvironmentalconcentration (pp~n) on aviadmamtnalian food items 'mg!ft2 "mg oftoxicant consumed per day 'Potential for acute toxicity for receptor species, even consideringrestricted use classification, if RQ > LOC (EPA, 2004). 'Potential for acutetoxicity for endangered species ofreceptor species if RQ > LOC (EPA, 2004). gEEC= ppb orppm in water "EEC = Ibs a.i.1A The LOCs are criteria used by OPP to indicate potential risk to non-target organisms and the need to consider regulatory action. The criteria indicate that a pesticide used as directed has thepotential to cause adverse effects on non-target organisms. LOCs currently address the following risk presumption categories: (I) acute 

### - potential for acute risk to non-listed species; regulatory action may be warranted in addition to restricted use classification, (2) acuterestricted use - potential for acute risk to non-listed species; however, risk maybe mitigated through restricted use classification, 

### (3) acute endangered species 

### - potential foracuterisk to endangered species; regulatory action may be warranted, and (4) chronic risk 

### - potential for chronic risk; regulatory action may be warranted. Currently, dueto lack of modeling applications, EFED does not perform assessments for chronic risk to plants, acute or chronic risks to non-target insects or chronic risk from granularhait formulations to mammalian or avian species.
For acute studies on taxa where no effects were observed at any concentration level, the RQs are not calculated and a qualitative discussion is provided in the Risk Description section. For acute studies on taxa where an LCsO/LDsO isnot established dueto insufficient mortality but some mortality was observed in the study, again, the RQs arenot calculated and the study is discussed further in the Risk Description section. The ecotoxicity test values (i.e., measurement endpoints) used in the acute and chronic risk quotients are derived from the results of required studies. Examples ofecotoxicity values derived from the results of short-term laboratory studies that assess acute effects are: (1) LCso (fish) (2) LD50(birds and mammals) 

### (3) EC50(aquatic plants and aquaticinvertebrates) and (4) EC25(terrestrial plants). An example of a toxicity test effect level derived from the results of long-term laboratory studythat assesses chronic effects is: NOAEC 

### (No Observed Adverse Effect Level; birds, fish and aquatic invertebrates).

### Appendix H. Data Requirements

# I. Guideline # 161-1 161-2
161-3
161-4 162-1
162-2
162-3
162-4
163-1

163-2 163-3 164-1

164-2
165-4
165-5
166-1 TABLE H-1. Environmental Data Requirement
Hydrolysis Photodegradation in Water Photodegradation on Soil Photodegradation in Air Aerobic Soil Metabolism Anaerobic Soil

Metabolism Anaerobic Aquatic Metabolism Aerobic Aquatic

MetabolismLeachingAdsorption/Desorption

Laboratory Volatility Field Volatility Terrestrial Field

Dissipation

Aquatic Field

Dissipation Accumulation in Fish

Aquatic non-target organism Ground Water- small

scaleprospective Fate Data MRID #

436898-02 44 1848-05 001537-09 44 1848-06

No Study 44 1848-07 001537-12 001537-13 No Study No Study
436898-03 436898-04 442873-13 001529-97 No Study No Study 442873-14 44 1848-09 001537-15 001537-16 001537-17 001537-18 No Study
44184812
No Study No Study Requirements for Propazine Study Classification Acceptable Acceptable Supplemental

Acceptable

Acceptable Acceptable Acceptable

Acceptable Acceptable Acceptable Acceptable

Supplemental Supplemental Unacceptable Unacceptable Unacceptable Unacceptable

Avaiting final EFEDreview Are more data needed? No No
No

No
No

Yes

Yes
NO

Yes

??71-4

72-1

72-2 72-3a 72-3b

72-4a 72-4b
72-4c
72-4d

72-5
72-7

- 81-1 82-l (a)

83-3

83-4
123-l(a) 123-l(b)

122-2 (bobwhite quail) (mallard duck) Avian reproduction

(bobwhite quail) (mallard duck) Freshwater fish acute LCjo0 (rainbow trout) (bluegill sunfish)
Freshwater invertebrate acute ECjO (daphnia) Estuarinelmarine fish acute LCjo (sheepshead minnow) Estuarineimarine invertebrate acute ECjo (eastern oyster) (mysid) Freshwater fish early life stage (fathead minnow) Freshwater invertebrate life cycle (daphnia) Estuarineimarine fish life cycle (sheepshead minnow) Estuarinelmarine invertebrate life cycle (mysid) Freshwater fish full life cycle Aquatic Field Study

~p - Acute mammalian oral LDSO (rat) Mammalian Subchronic Mammalian Develop~nental (rat) (rabbit) Mammalian Reproduction (rat) Seedling Emergence - Tier ll

Vegetative Vigor - Tier II Aquatic plant algae (green algae) (blue-green algae) (diatom) (marine diatom) 442873-02 442873-03
N/A

NIA 442873-04

442873-05 N/A

442873-06 44 1848-01 442837-07 443276-02
44 1848-02

441848-03
NIA
NIA 434741-01
NIA 00 1502-42 44 1534-01 0004 14-09 441 848-04
44 1848-04

442873-08 442873- 12 442873-10 442873-1 1 Core Core

-- Invalid Awaitingfinal EFED review

AwaitingJinal EFED review Acceptable Supplemental Core Awaitingjt~al EFED review
Supplemental

Acceptable

Acceptable Acceptable Acceptable Awaitingjnal EFED review Awaitingjnal EFED review Core Core Core Core No

Yes

Yes

? ?
Yes

??

Yes
No ? ?

Yes

No

No

No ? ? ??

No

### Appendix 

### I. EnvironmentalFate BibliographyKeller, A. 1979b. Degradation ofpropazine (Gesamil) in aerobic soil. Project Report No. 15/79. Unpublished studyprepared by Ciba-Geigy, Ltd., Basle, Switzerland. MRID 001537-12. Hughes, D. L. 1996. Field Soil Dissipation ofPropazine (~ilo-~ro~~ 4L) on Bare Soil in North Carolina. Laboratory Project Identification CHW Study No. 664 1 

### - 100A. Unpublished study performed by Coming Hazelton Inc, Madison, WI, and submitted by Griffin Corporation, Valdosta, GA. MRID 442873-14. Hughes, D. 

### L. 1996. Field Soil Dissipation ofPropazine (~ilo-pro~~ 4L) on Bare Soil in Texas. Laboratory Project Identification CHW StudyNo. 6641-100. Unpublished study performed by Coming Hazelton Inc, Madison, WI, and submittedby Griffin Corporation, Valdosta, GA. MRID 441848-09. Mobley, S. G. 1994. Solution Photolysis of [14~]~ropazine n Artificial Light. Laboratory Project ID No. 85 1Report No. 1644. Unpublished studyperformed by PTRL East, Inc., Richmond, KY, and submitted by Griffin Corporation, Valdosta, GA. MRID 441848-05 Mobley, S. G. 1994. Soil Surface Photolysis of [14~]~ropazine n Artificial Light. Laboratory Project ID No. 852 Report No. 1645. Unpublished studyperformed by PTRL East, Inc., Richmond, KY, and submitted by Griffin Corporation, Valdosta, GA. MRID 441848-06 Perdue, D. 1994. Hydrolysis of ['4~]~ropazine i Aqueous Buffered Solutions at pH 5, 7 and 9. Project No. 850. Report No. 1640. Unpublished studyperformed by PTRL East, Inc., Richmond, KY, and submitted by Griffin Corporation, Valdosta, GA. MRID 436898-02. Perdue, D. 1995. Soil AdsorptiodDesorption of 

### 2-~~drox~-['~~]~ro~azine by the Batch Equilibrium Method. Project No. 91 3. Report No. 1 8 17. Unpublished studyperformed by PTRL East, Inc., Richmond, KY, and submitted by Griffin Corporation, Valdosta, GA. MRID 442873- 13. Perdue, D. 1995. Column Leaching of [14C]~ropazine in Four Soil Types Following Aerobic Aging. Project No. 855. Report No. 1660. Unpublished study performed by PTRL East, Inc., Richmond, KY, and submitted by Griffin Corporation, Valdosta, GA. MRID 436898-03. Perdue, D. 1995b. Soil AdsorptiodDesorption of [14~]~ropazine by the Batch Equilibrium Method. Project No. 853. Report No. 1653. Unpublished study performed by PTRL East, Inc., Richmond, KY, and submitted by Griffin Corporation, Valdosta, GA. MRID 436898-04. Perdue, D. 1995. Aerobic Soil Metabolism of [14~]~ropazine in SandyLoam. Project No. 865. Report No.1661. Unpublished studyperformed by PTRL East, Inc., Richmond, 

### KY, and submitted by Griffin Corporation, Valdosta, GA. MRID 441 848-07.

### Appendix J. 

### Ecological Toxicity BibliographyAtkins, E.L., E.A. Greywood and R.L. MacDonald. 1975. Toxicity of pesticides and other agricultural chemicals to honey bees. University of California, Division of Agricultural Science Leaflet 2287. 38pp. FicheIMaster ID 00036935. Boeri, R.L., P.L. Kowalski, and T.J. Ward. 1995. Chronic toxicity of propazine to the mysid, 

### mysidopsis bahia. Unpublished study performed by T.R. Wilbury Laboratories, Inc. Marblehead, MA. Laboratory Project ID No. 573-AB. Study submitted by Griffin Corporation, Valdosta, GA. MRID 441 848-03. Boeri, R.L., P.L. Kowalski, and T.J. Ward. 1995. Early life-stage toxicity ofpropazine to the sheepshead minnow, 

### Cyprinodon variegates. Unpublished studyperformed by 

### T.R. Wilbury Laboratories, Inc. Marblehead, MA and ABC Laboratories, Inc., Environmental Toxicology Division, Columbia, MO. Study submittedby Griffin Corporation, Valdosta, GA. MRID 441 848-02. Boeri, R.L., P.L. Kowalski, and T.J. Ward. 1995. Flow through shell deposition test with propazine and the eastern oyster, 

### Crassostrea virginica. Unpublished studyperformed by T.R. Wilbury Laboratories, Inc. Marblehead, MA and ABC Laboratories, Inc., Environmental Toxicology Division, Columbia, MO. Laboratory Project ID No. 41956. Study submitted by Griffin Corporation,Valdosta, GA. MRID 442873-06. Boeri, R.L., P.L. Kowalski, and T.J. Ward. 1995. Static acute toxicity ofpropazine to the mysid, 

### mysidopsis bahia. Unpublished studyperformed by T.R. Wilbury Laboratories, Inc. Marblehead, MA. Laboratory Project ID No. 571-AB. Study submitted by Griffin Corporation, Valdosta, GA. MRID 44 1848-01. Bowman, J. and J. Veltri. 1995. Acute toxicity of propazine to bluegill 

### (Lepomis macrochirus). Unpublished studyperformed by ABC Laboratories, Inc., Environmental Toxicology Division, Columbia, MO. Laboratory Project ID No. 41953. Study submittedby Griffin Corporation, Valdosta, GA. MRID 442873-04. Gledhill, D.W. and J.B. Bussard. 1995. Acute toxicity ofpropazine to

### Anabaenaflos-aquae. Unpublished studyperformed by ABC Laboratories, Inc., Environmental ToxicologyDivision, Columbia, MO. Laboratory Project ID No. 41968-9. Study submittedby Griffin Corporation, Valdosta, GA. MRID 442873- 12. Gledhill, D.W. and J.B. Bussard. 1995. Acute toxicity ofpropazine to 

### Skeletonema costatum. Unpublished studyperformed by ABC Laboratories, Inc., Environmental Toxicology Division, Columbia, MO. Laboratory Project ID No. 41967. Study submitted by Griffin Corporation, Valdosta, GA. MRID 442873- 11. Hicks, S.L., J.B. Bussard, and D.W. Gledhill. 1995. Acute toxicity ofpropazine to 

### Selenastrum capricornutum. Unpublished study performed by ABC Laboratories, Inc., Environmental Toxicology Division, Columbia, MO. Laboratory Project ID No. 41962. Study submitted by Griffin Corporation, Valdosta, GA. MRID 442873-08.Hicks, S.L. and D.W. Gledhill. 1995. Acute toxicity ofpropazine toNaviculapelliculosa. Unpublished studyperformed by ABC Laboratories, Inc., Environmental ToxicologyDivision, Columbia, MO. Laboratory Project ID No. 41966. Study submitted by Griffin Corporation, Valdosta, GA. MRID 442873-10. Hicks, S.L., Gledhill, D.W. and J. Veltri. 1995. 14-Day static toxicity ofpropazine to Lemna gibba. Unpublished studyperformed by ABC Laboratories, Inc., Environmental Toxicology Division, Columbia, MO. Laboratory Project ID No. 41963. Study submitted by Griffin Corporation, Valdosta, GA. MRID 442873-09. Jameson, C.E. and J. Veltri. 1995. Acute dietary toxicity of propazine to bobwhite quail (Colinusvirginianus). Unpublished study performed by ABC Laboratories, Inc., Environmental Toxicology Division, Columbia, MO. Laboratory Project ID No. 41758. Study submitted by Griffin Corporation, Valdosta, GA. MRID 442873-02. Jameson, C.E. and J. Veltri. 1995. Acute dietary toxicity ofpropazine to mallard ducks (Anas platyrhynchos). Unpublished studyperformed by ABC Laboratories, Inc., Environmental Toxicology Division, Columbia, MO. Laboratory Project ID No. 41759. Study submitted by Griffin Corporation, Valdosta, GA. MRID 442873-03. Jameson, C.E. and J. Veltri. 1995. Acute oral toxicity of propazine to bobwhite quail (Colinus virginianus). Unpublished study performed by ABC Laboratories, Inc., Environmental Toxicology Division, Columbia, MO. Laboratory Project ID No. 4 1757. Study submitted by Griffin Corporation, Valdosta, GA. MRID 442873-01. Jessup, D.C. et al. 1979. Three generation reproduction study in rats. International Research and Development Corporation, Mattawan, MI. Report No. 382-010. Study submitted by CibaGeigy Corporation. MRID 00041 4-09. Knapp, J.F. 1995. A developmental toxicity study ofpropazine technical in rabbits. WIL Research Laboratories, Inc., Ashland, Ohio. Laboratory Study No. WIL-157005. Study submittedby Griffin Corporation, Valdosta, GA. MRID 441 534-01. Kuhn, J.O. 1994. Acute oral toxicity ofpropazine to Sprague-Dawley rats. Unpublished study performed by Stillmeadow, Inc. Laboratory Study No. 1318-94. Study submitted by Griffin Corporation, Valdosta, GA. MRID 43474 1-01. Murrell, H.R. 1994. Acute toxicity of propazine to Daphnia magna. Unpublished study performed by ABC Laboratories, Inc., Environmental Toxicology Division, Columbia, MO. Laboratory Project ID No. 41954. Study submitted by Griffin Corporation, Valdosta, GA. Definitive study conducted September 21
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### GA. MRID 44 1 848-04.