Environmental Fate, Ecological Risk and

Endangered Species Assessment

in Support of the Registration Review of

Fomesafen Sodium (PC123802)

Prepared by:

Paige D. Doelling, PhD, Fisheries Biologist

Stephen P. Wente, PhD, Biologist	U. S. Environmental Protection Agency

Office of Pesticide Programs

Environmental Fate and Effects Division

Environmental Risk Branch I

1200 Pennsylvania Ave., NW

Mail Code 7507P

Washington, DC 20460

Reviewed by:

Faruque Khan, PhD, Senior Fate Scientist

December 2008

Table of Contents

  TOC \h \z \t "ERA Heading 1,1,ERA Heading 2,2,ERA Heading 3,3,ERA Heading 4,3,Appendix Header,1"    HYPERLINK \l "_Toc221951908"  1.0 Executive Summary	  PAGEREF _Toc221951908 \h  6

  HYPERLINK \l "_Toc221951909"  1.1	Nature of Stressor	  PAGEREF _Toc221951909 \h  6

  HYPERLINK \l "_Toc221951910"  1.2	Potential Risk	  PAGEREF _Toc221951910 \h  6

  HYPERLINK \l "_Toc221951911"  1.3	Endangered Species Assessment	  PAGEREF _Toc221951911 \h  7

  HYPERLINK \l "_Toc221951912"  2.0	Problem Formulation	  PAGEREF _Toc221951912 \h  9

  HYPERLINK \l "_Toc221951913"  2.1	Stressor Description	  PAGEREF _Toc221951913 \h  9

  HYPERLINK \l "_Toc221951914"  2.2	Environmental Fate Summary	  PAGEREF _Toc221951914 \h  9

  HYPERLINK \l "_Toc221951915"  2.3	Mode of Action	  PAGEREF _Toc221951915 \h  10

  HYPERLINK \l "_Toc221951916"  2.4	Use Characterization	  PAGEREF _Toc221951916 \h  10

  HYPERLINK \l "_Toc221951917"  2.5	Assessment Endpoints	  PAGEREF _Toc221951917 \h  12

  HYPERLINK \l "_Toc221951918"  2.5.1	Ecosystems Potentially at Risk	  PAGEREF _Toc221951918 \h  13

  HYPERLINK \l "_Toc221951919"  2.5.2	Ecological Effects	  PAGEREF _Toc221951919 \h  13

  HYPERLINK \l "_Toc221951920"  <IP_ADDRESS>	Direct	  PAGEREF _Toc221951920 \h  13

  HYPERLINK \l "_Toc221951921"  <IP_ADDRESS>	Indirect	  PAGEREF _Toc221951921 \h  13

  HYPERLINK \l "_Toc221951922"  2.6	Risk Hypotheses	  PAGEREF _Toc221951922 \h  15

  HYPERLINK \l "_Toc221951923"  2.7	Results of Previous Assessments	  PAGEREF _Toc221951923 \h  15

  HYPERLINK \l "_Toc221951924"  2.8	Analysis Plan	  PAGEREF _Toc221951924 \h  16

  HYPERLINK \l "_Toc221951925"  3.0	Exposure Assessment	  PAGEREF _Toc221951925 \h  17

  HYPERLINK \l "_Toc221951926"  3.1	Label Application Rates and Intervals	  PAGEREF _Toc221951926 \h  17

  HYPERLINK \l "_Toc221951927"  3.2	Aquatic Exposure	  PAGEREF _Toc221951927 \h  18

  HYPERLINK \l "_Toc221951928"  3.2.1	PRZM-EXAMS Modeling Inputs and Scenario Selection	  PAGEREF _Toc221951928 \h  18

  HYPERLINK \l "_Toc221951929"  3.2.2	PRZM-EXAMS Modeling Output	  PAGEREF _Toc221951929 \h  19

  HYPERLINK \l "_Toc221951930"  3.2.3	Registrant-submitted Aquatic Exposure Modeling	  PAGEREF _Toc221951930 \h  20

  HYPERLINK \l "_Toc221951931"  3.2.4	SCIGROW Modeling for Ground Water	  PAGEREF _Toc221951931 \h  20

  HYPERLINK \l "_Toc221951932"  3.2.5	Soil Accumulation	  PAGEREF _Toc221951932 \h  21

  HYPERLINK \l "_Toc221951933"  3.3	National Surface Water Monitoring Data	  PAGEREF _Toc221951933 \h  23

  HYPERLINK \l "_Toc221951934"  3.3.1	Surface Water	  PAGEREF _Toc221951934 \h  23

  HYPERLINK \l "_Toc221951935"  3.3.2	Ground Water	  PAGEREF _Toc221951935 \h  23

  HYPERLINK \l "_Toc221951936"  3.4	Bird and Mammal Exposure (TREX)	  PAGEREF _Toc221951936 \h  24

  HYPERLINK \l "_Toc221951937"  3.5	Terrestrial Invertebrate Exposure	  PAGEREF _Toc221951937 \h  26

  HYPERLINK \l "_Toc221951938"  3.6	Terrestrial Plant Exposure (TerrPlant & AgDrift)	  PAGEREF _Toc221951938 \h  27

  HYPERLINK \l "_Toc221951939"  3.6.1	TerrPlant	  PAGEREF _Toc221951939 \h  27

  HYPERLINK \l "_Toc221951940"  3.6.2	AgDrift	  PAGEREF _Toc221951940 \h  28

  HYPERLINK \l "_Toc221951941"  4.0	Effects Assessment	  PAGEREF _Toc221951941 \h  30

  HYPERLINK \l "_Toc221951942"  4.1	Specific Toxicological Concerns Associated with this Chemical	  PAGEREF _Toc221951942 \h  30

  HYPERLINK \l "_Toc221951943"  4.2	Aquatic Hazard Summary	  PAGEREF _Toc221951943 \h  31

  HYPERLINK \l "_Toc221951944"  4.3	Summary of Aquatic Ecotoxicity Studies	  PAGEREF _Toc221951944 \h  33

  HYPERLINK \l "_Toc221951945"  4.3.1	Aquatic Guideline Data	  PAGEREF _Toc221951945 \h  33

  HYPERLINK \l "_Toc221951946"  4.3.2	Aquatic Data from ECOTOX	  PAGEREF _Toc221951946 \h  33

  HYPERLINK \l "_Toc221951947"  4.4	Terrestrial Hazard Summary	  PAGEREF _Toc221951947 \h  35

  HYPERLINK \l "_Toc221951948"  4.5	Summary of Terrestrial Ecotoxicity Studies	  PAGEREF _Toc221951948 \h  36

  HYPERLINK \l "_Toc221951949"  4.5.1	Avian and Small Mammal Guideline Data	  PAGEREF _Toc221951949 \h  36

  HYPERLINK \l "_Toc221951950"  4.5.2	Terrestrial Plant Data	  PAGEREF _Toc221951950 \h  36

  HYPERLINK \l "_Toc221951951"  <IP_ADDRESS>	Guideline Studies	  PAGEREF _Toc221951951 \h  36

  HYPERLINK \l "_Toc221951952"  <IP_ADDRESS>	Additional Registrant-Submitted Data	  PAGEREF _Toc221951952 \h  37

  HYPERLINK \l "_Toc221951953"  4.5.3	Terrestrial Insect Data	  PAGEREF _Toc221951953 \h  38

  HYPERLINK \l "_Toc221951954"  4.5.4	ECOTOX Data	  PAGEREF _Toc221951954 \h  38

  HYPERLINK \l "_Toc221951955"  <IP_ADDRESS>	Biochemical Endpoints	  PAGEREF _Toc221951955 \h  38

  HYPERLINK \l "_Toc221951956"  <IP_ADDRESS>	Aquatic Community-Level	  PAGEREF _Toc221951956 \h  39

  HYPERLINK \l "_Toc221951957"  4.5.5	Carcinogenicity, Mutagenicity, and Endocrine Disruption	  PAGEREF _Toc221951957 \h  40

  HYPERLINK \l "_Toc221951958"  4.5.6	Toxic Effects of Multi-Active Ingredient Labeled Products	  PAGEREF _Toc221951958 \h  40

  HYPERLINK \l "_Toc221951959"  4.6	Incident Database Review	  PAGEREF _Toc221951959 \h  41

  HYPERLINK \l "_Toc221951960"  5.0	Risk Estimation	  PAGEREF _Toc221951960 \h  42

  HYPERLINK \l "_Toc221951961"  5.1	Aquatic RQ Summary	  PAGEREF _Toc221951961 \h  43

  HYPERLINK \l "_Toc221951962"  5.2	Terrestrial RQ Summary	  PAGEREF _Toc221951962 \h  44

  HYPERLINK \l "_Toc221951963"  5.2.1	Terrestrial Plants	  PAGEREF _Toc221951963 \h  44

  HYPERLINK \l "_Toc221951964"  <IP_ADDRESS>	TerrPlant	  PAGEREF _Toc221951964 \h  44

  HYPERLINK \l "_Toc221951965"  <IP_ADDRESS>	AgDrift	  PAGEREF _Toc221951965 \h  46

  HYPERLINK \l "_Toc221951966"  5.2.2	Avian RQ Summary	  PAGEREF _Toc221951966 \h  47

  HYPERLINK \l "_Toc221951967"  5.2.3	Small Mammal RQ Summary	  PAGEREF _Toc221951967 \h  48

  HYPERLINK \l "_Toc221951968"  5.2.4	Terrestrial Invertebrate Summary	  PAGEREF _Toc221951968 \h  48

  HYPERLINK \l "_Toc221951969"  6.0	Risk Description	  PAGEREF _Toc221951969 \h  50

  HYPERLINK \l "_Toc221951970"  6.1	Aquatic Risk	  PAGEREF _Toc221951970 \h  50

  HYPERLINK \l "_Toc221951971"  6.2	Terrestrial Risk	  PAGEREF _Toc221951971 \h  53

  HYPERLINK \l "_Toc221951972"  6.2.1	Birds, Reptiles, and Amphibians	  PAGEREF _Toc221951972 \h  53

  HYPERLINK \l "_Toc221951973"  6.2.2	Mammals	  PAGEREF _Toc221951973 \h  54

  HYPERLINK \l "_Toc221951974"  6.2.3	Terrestrial Invertebrates	  PAGEREF _Toc221951974 \h  54

  HYPERLINK \l "_Toc221951975"  6.2.4	Plants	  PAGEREF _Toc221951975 \h  56

  HYPERLINK \l "_Toc221951976"  6.3	Endangered Species	  PAGEREF _Toc221951976 \h  58

  HYPERLINK \l "_Toc221951977"  6.3.1	Aquatic Listed Species	  PAGEREF _Toc221951977 \h  58

  HYPERLINK \l "_Toc221951978"  6.3.2	Terrestrial Listed Species	  PAGEREF _Toc221951978 \h  59

  HYPERLINK \l "_Toc221951979"  6.3.3	Plants	  PAGEREF _Toc221951979 \h  65

  HYPERLINK \l "_Toc221951980"  6.3.4	Action Area	  PAGEREF _Toc221951980 \h  66

  HYPERLINK \l "_Toc221951981"  6.3.5	Probability of Individual Effects	  PAGEREF _Toc221951981 \h  68

  HYPERLINK \l "_Toc221951982"  6.4	Risk Conclusions	  PAGEREF _Toc221951982 \h  70

  HYPERLINK \l "_Toc221951983"  7.0	Uncertainties	  PAGEREF _Toc221951983 \h  72

  HYPERLINK \l "_Toc221951984"  7.1	Exposure Assessment Uncertainties	  PAGEREF _Toc221951984 \h  72

  HYPERLINK \l "_Toc221951985"  7.1.1	Aquatic Exposure	  PAGEREF _Toc221951985 \h  72

  HYPERLINK \l "_Toc221951986"  <IP_ADDRESS>	Modeling Assumptions	  PAGEREF _Toc221951986 \h  72

  HYPERLINK \l "_Toc221951987"  <IP_ADDRESS>	Monitoring Data	  PAGEREF _Toc221951987 \h  72

  HYPERLINK \l "_Toc221951988"  <IP_ADDRESS>	Impact of Vegetative Setbacks on Runoff	  PAGEREF _Toc221951988 \h  72

  HYPERLINK \l "_Toc221951989"  <IP_ADDRESS>	PRZM Modeling Inputs and Predicted Aquatic Concentrations	  PAGEREF _Toc221951989 \h  73

  HYPERLINK \l "_Toc221951990"  7.1.2	Terrestrial Exposure Uncertainties   PAGEREF _Toc221951990 \h  73

  HYPERLINK \l "_Toc221951991"  <IP_ADDRESS>	Residue Levels Selection	  PAGEREF _Toc221951991 \h  74

  HYPERLINK \l "_Toc221951992"  <IP_ADDRESS>	Dietary Intake	  PAGEREF _Toc221951992 \h  74

  HYPERLINK \l "_Toc221951993"  7.2	Effects Assessment Uncertainties	  PAGEREF _Toc221951993 \h  75

  HYPERLINK \l "_Toc221951994"  7.2.1	Age Class and Sensitivity of Effects Thresholds	  PAGEREF _Toc221951994 \h  75

  HYPERLINK \l "_Toc221951995"  7.2.2	Use of Surrogate Species Data	  PAGEREF _Toc221951995 \h  75

  HYPERLINK \l "_Toc221951996"  7.2.3	Extrapolation of Effects	  PAGEREF _Toc221951996 \h  75

  HYPERLINK \l "_Toc221951997"  7.2.4	Acute LOC Assumptions	  PAGEREF _Toc221951997 \h  75

  HYPERLINK \l "_Toc221951998"  References	  PAGEREF _Toc221951998 \h  76

  HYPERLINK \l "_Toc221951999"  Guideline Study References	  PAGEREF _Toc221951999 \h  76

  HYPERLINK \l "_Toc221952000"  ECOTOX References	  PAGEREF _Toc221952000 \h  81

Appendix A – Exposure and Modeling

Appendix B – Ecological Effects

Appendix C – ECOTOX Bibiligraphy

Appendix D – RQ Method and LOCs

Appendix E – Analysis Summary

Appendix F – LOCATES (Endangered Species)

Appendix G – Spray Drift Analysis

Table of Figures

  TOC \c "Figure"  Figure 1 Chemical structure of fomesafen	  PAGEREF _Toc217883368 \h  9

Figure 2 Conceptual model for fomesafen effects	  PAGEREF _Toc217883369 \h  14

Figure 3. Estimate of Fomesafen Loading in the Surface Soil	  PAGEREF _Toc217883370 \h  23

Table of Tables

  TOC \c "Table"  Table 1  Summary of Direct and Indirect Effects	  PAGEREF _Toc221940748 \h  8

Table 2  Current Fomesafen Registrations	  PAGEREF _Toc221940749 \h  11

Table 3  Summary of Assessment Endpoints and Measures of Ecological Effect	  PAGEREF _Toc221940750 \h  12

Table 4  Label Application Rates and Intervals for Fomesafen Use on Soybeans, Cotton, Snap Beans and Dry Beans1	  PAGEREF _Toc221940751 \h  17

Table 5  Label Application Rates and Intervals for Section 24c Uses of Fomesafen	  PAGEREF _Toc221940752 \h  18

Table 6.  Input Parameters for PRZM-EXAMS Modeling of Fomesafen on Cotton, Soybeans, Dry Beans, and Snap Bean	  PAGEREF _Toc221940753 \h  19

Table 7.  PRZM-EXAMS Aquatic EECs for Fomesafen	  PAGEREF _Toc221940754 \h  20

Table 8  PRZM-EXAMS EECs for Fomesafen at 0.50 lb ai/A	  PAGEREF _Toc221940755 \h  20

Table 9.  Input Parameters for SCIGROW Modeling for Fomesafen	  PAGEREF _Toc221940756 \h  21

Table 10 Label Application Rates and Intervals for Fomesafen Use on Soybeans, Cotton, Snap Beans, and Dry Beans1	  PAGEREF _Toc221940757 \h  21

Table 11  Input Parameters for TREX Modeling	  PAGEREF _Toc221940758 \h  24

Table 12  Bird Dose Estimates	  PAGEREF _Toc221940759 \h  25

Table 13  Mammal Dose Estimates	  PAGEREF _Toc221940760 \h  26

Table 14  Terrestrial Invertebrate Exposure	  PAGEREF _Toc221940761 \h  26

Table 15  Terrestrial Plant Exposure	  PAGEREF _Toc221940762 \h  27

Table 16  Drift Deposition from Ground Applications	  PAGEREF _Toc221940763 \h  29

Table 17  Drift Depostion from Aerial Applications	  PAGEREF _Toc221940764 \h  29

Table 18  Aquatic Toxicity Profile for Fomesafen	  PAGEREF _Toc221940765 \h  32

Table 19  Terrestrial Toxicity Profile for Fomesafen	  PAGEREF _Toc221940766 \h  35

Table 20  Drift Deposition from Aerial Applications	  PAGEREF _Toc221940767 \h  46

Table 21  Drift Deposition from Ground Applications	  PAGEREF _Toc221940768 \h  46

Table 22  Avian RQ Summary	  PAGEREF _Toc221940769 \h  47

Table 23  Small Mammal RQ Summary	  PAGEREF _Toc221940770 \h  48

Table 24  Terrestrial Invertebrate RQ Summary	  PAGEREF _Toc221940771 \h  49

Table 25  Summary of Risk to Non-listed Aquatic Organisms	  PAGEREF _Toc221940772 \h  52

Table 26  Comparison of Chronic Data for Acifluorfen, Fomesafen, and Oxyfluorfen.	  PAGEREF _Toc221940773 \h  54

Table 27  Summary of Risk to Non-Listed Terrestrial Animals	  PAGEREF _Toc221940774 \h  55

Table 28  Summary of Risk to Non-listed Terrestrial Plants	  PAGEREF _Toc221940775 \h  57

Table 29  Summary of Risk to Listed Aquatic Organisms	  PAGEREF _Toc221940776 \h  58

Table 30  Summary of Risk to Listed Terrestrial Animals	  PAGEREF _Toc221940777 \h  60

Table 31.  Listed birds potentially at risk from fomesafen	  PAGEREF _Toc221940778 \h  62

Table 32.  Listed reptiles and amphibians potentially at risk from fomesafen	  PAGEREF _Toc221940779 \h  63

Table 33  Summary of Risk to Listed Plants	  PAGEREF _Toc221940780 \h  64

Table 34  Endangered Plants by Crop and State	  PAGEREF _Toc221940781 \h  67

Table 35  Probability of Individual Effects	  PAGEREF _Toc221940782 \h  69

Table 36  Summary of Direct and Indirect Effects	  PAGEREF _Toc221940783 \h  71

1.0	Executive Summary

1.1	Nature of Stressor

Fomesafen is an herbicide.  It is applied as a foliar spray (both pre-emergent and post-emergent) for control of broad-leaved weeds, grasses, and sedges.  Mode of action is via cellular membrane disruption.  It is highly persistent in soil (aerobic soil metabolism half-lives of 29-99 weeks, dependent on soil type) resulting in a potential for accumulation in terrestrial environments.  The label suggests not planting sensitive crops in a fomesafen-treated field for a 3-18 month period, due to the persistence of fomesafen in the soil. Additionally, it is highly mobile, and is expected to leach into groundwater and be transported from the site via runoff into surface waters.  Based on physical properties, bioaccumulation and long-range transport are not expected to be of concern.  It is extremely toxic to terrestrial plants, especially dicots, but of fairly low acute toxicity to fish and wildlife.  Some chronic reproductive effects have been noted in mammals, and may also occur in birds. No major degradates of toxicological concern have been identified.

Potential Risk

Chemical Properties

Fomesafen is highly persistent and mobile in soil.  These environmental fate properties are expected to promote year-to-year accumulation in soil as well as off-site movement by leaching and runoff.  Because fomesafen is spray applied, there is a potential for drift onto non-target plants.  Prolonged phytotoxic effects on non-target plants are expected based on the persistence of fomesafen.  EFED has no data from which to determine how long it may be toxic, but the labels recommend not planting sensitive crops in the use site for 3 to 18 months following treatment.

Ecological Risk Conclusions

Ecologically, the organisms most at risk from fomesafen are terrestrial plants, especially dicots.  Because terrestrial plants are important both ecologically (they provide a critical part of both the structure and function that defines “habitat”) and economically (nearby non-target, non-treated crop plants may be affected), these potential impacts are an important consideration.  No LOCs were exceeded for aquatic endpoints except the listed species LOC for freshwater non-vascular plants.  At the time of this assessment, there were no listed non-vascular freshwater plants, and no listed species had been identified as having an obligate relationship with freshwater non-vascular plants.  For terrestrial organisms, chronic LOCs were exceeded for birds (and by extension, reptiles and amphibians) at all but the lowest application rate.  Chronic LOCs were exceeded for mammals only for small herbivorous mammals at the highest application rate.  These LOC exceedences apply to both listed and non-listed species.  Based on spray drift estimations, clearance distances for chronic exceedences are well within the clearance distances for terrestrial plants, thus if terrestrial plants are protected, then by virtue of sensitivity, other vulnerable organisms should be protected as well.  Clearance distances for chronic effects on birds, reptiles, amphibians, and mammals are 10 ft from the application source for ground applications (based on low boom estimates) and 100 ft for aerial applications (based on application parameters used in AgDrift Tier I estimates).  For terrestrial plants, using drift estimates based on the more sensitive dicots, effects should be anticipated as far as 850 ft for ground applications, and 1,000 ft for aerial applications.

Endangered Species Assessment

For listed animals, both aquatic and terrestrial, the primary risk posed by use of fomesafen as currently registered under Section 3 is due to potential degradation of plant communities providing food, shelter, or protection from predators.  On the basis of these indirect effects and the anticipated magnitude of such effect, an overall determination of may affect, likely to adversely affect applies to all listed species located with 850 ft of the application location.  The action area, based on the furthest extent at which an LOC is exceeded (dicots), is 1,000 ft away from agricultural land in geographic areas where fomesafen is registered for use.  A list of potentially affected species is included as Appendix F.  No direct effects are anticipated for aquatic organisms, constituting a no effect determination for these organisms on the basis of direct effects.  Based on available data, there is a chronic risk to birds, reptiles, and terrestrial-phase amphibians.  The Agency is unable to evaluate the potential magnitude of these chronic effects, thus the overall determination for these taxa is may affect, likely to adversely affect.

≤100 ft

Aerial ≤100 ft

from point of application	Yes

Potential for effects on other plants in the community.  Alteration of habitat may create environment unsuitable to the listed species.

Effects may occur up to

Ground ≤300 ft

Aerial ≤900 ft

from point of application	No?

(only listed monocot affected is aquatic)

Dicots	Other1	Yes

Ground ≤300 ft

Aerial ≤900 ft

from point of application

No

(No potentially affected species have designated critical habitat)

	Dicots

	Yes

(6 potentially affected species have designated critical habitat)

Birds	Birds	Yes

Chronic Exceedences

Ground ≤10 ft

Aerial ≤100 ft

from point of application	Yes

Potential for effects on other plants in the community.  Alteration of habitat may create environment unsuitable to the listed species.

Effects may occur up to

Ground ≤300 ft

Aerial ≤900 ft

from point of application	Yes

Potential for effects on other plants in the community.  Alteration of habitat may create environment unsuitable to the listed species.

Effects may occur up to

Ground ≤300 ft

Aerial ≤900 ft

from point of application

	Reptiles

Terrestrial Phase Amphibians

	Mammals	Mammals

	FW Aquatic Plants2	FW Aquatic Plants	No

No LOC exceedences

SW Aquatic Plants	SW Aquatic Plants

	FW Aquatic Invertebrates	FW Crustacea

FW Bivalves

FW Gastropods

	FW Fish	FW Fish

Aquatic Phase Amphibians

	SW Aquatic Invertebrates	SW Crustacea

SW Bivalves

SW Gastropods

	SW Fish	SW Fish

	1 Cycads, Conifers, Fern Allies. These genera have no direct corollary test organism, and have been evaluated based on the most sensitive plant endpoint.

2 Evaluated based on both non-vascular plants (algae) and vascular plants (duckweed)

2.0	Problem Formulation

Problem formulation provides a strategic framework for the risk assessment.  By identifying the important components of the problem, it focuses the assessment on the most relevant chemical properties, exposure routes, and endpoints.

Stressor Description

Fomesafen is applied as a pre-plant, pre-emergence, and post-emergence herbicide in soybeans, snap beans, dry beans, and cotton for control of broadleaf weeds, grasses, and sedges. Fomesafen can be applied via ground and aerial sprays. Because fomesafen is persistent in soil (aerobic soil degradation t1/2 = 29 to 99 weeks at 0.50 lb ai/A application rate; MRID 00135660), residual in soil of the treated field is considered in this risk assessment as a secondary source.

Figure   SEQ Figure \* ARABIC  1  Chemical structure of fomesafen

Empirical formula:	C15H10ClF3N2O6S

Molecular weight:	438.77 g/mole

CAS Registry Nos.:	72178-02-0

Chemical Class:	Diphenyl ether

Environmental Fate Summary

Major routes of fomesafen dissipation are leaching, runoff, and microbial degradation. Because fomesafen is persistent and mobile in soil, it is expected to move from the application site into groundwater and surface water. Additionally, off-site movement of fomesafen is expected through spray drift from aerial and ground spray. The high persistence of fomesafen is expected to contribute to year-to-year accumulation in terrestrial and aquatic environments.

Fomesafen is stable to abiotic hydrolysis. It undergoes slow photodegradation in water

(t1/2 = 49 to 289 days). Fomesafen is persistent (aerobic soil t1/2 = 29 to 99 weeks) in aerobic soil and aquatic environments. However, it degrades rapidly (t1/2 <20 days) in anaerobic environments. The major degradation product of fomesafen is 5-(2-chloro-(,(,(-trifluoro-p-tolyloxy)-N-methylsulphonyl-panthranilamid e (fomesafen amine). A minor degradation product is 5-(2-chloro-(,(,(-trifluoro-p-tolyloxy) anthranilic acid (fomesafen amino acid). Neither degradate has been identified as a toxicological concern.

Fomesafen is expected to be very mobile in soil. Simple partitioning coefficients range from 0.51 in loamy coarse sand to 2.45 in sandy clay loam soil. Regression analysis indicates fomesafen sorption is not dependent on soil organic matter content. Aged soil column leaching studies indicate degradation products of fomesafen are not mobile in soils; less than 0.06% of applied radioactivity was detected in the leachate samples.

Field dissipation studies in NC, IL, MS, AR, AL, TX, LA, SD, MN, KY, IA, and MO indicate fomesafen is moderately persistent to persistent (t1/2 = 50 to 150 days ) in surface soils under actual use conditions. Fomesafen was detected at depths up to 30 inches in the soil profile. Fomesafen amine was the only degradation product identified in field dissipation studies. Prospective ground water monitoring in NC indicates fomesafen moved through the soil profile into medium and deep ground water.

Fomesafen has a low potential for bioaccumulation in fish tissues. Bioaccumulation factors for fosmesafen were 0.7 for whole fish, 0.2 for edible tissues, and 5.2 for nonedible tissue. Bioaccumulated residues decreased by 95% during a 14-day depuration period.

 2.3	Mode of Action

Fomesafen is a diphenyl ether. It disrupts the cell membrane of the plant (  HYPERLINK "http://www.syngentacroprotection-us.com"  www.syngentacroprotection-us.com ) by penetrating into the cytoplasm and causing formation of peroxides and free electrons (http://www.ces.purdue.edu/extmedia/WS/WS-23-W.html). The specific mode of action is inhibition of protoporphyrinogen oxidase (Roberts 1998  HYPERLINK http://www.weeds.iastate.edu)  ) . Fomesafen generally acts quickly, and does not translocate. It has both foliar and soil activity. Other herbicides in this group include aciflourfen, lactofen, and oxyfluorfen.

2.4	Use Characterization

Fomesafen is used primarily as a pre-plant, pre-emergence, and post-emergence herbicide to control broadleaf weeds, grasses, and sedges in soybeans, snap beans, dry beans, and cotton. Methods of application are ground spray and aerial spray (maximum 0.375 lb ai/A, soybeans, dry beans, snap beans, and cotton). Application is limited to once a year, or in alternate years, depending on location. Application rates are regionally specific.

A search of OPPIN on 4/24/2008 (PDD) located 20 active Section 3 and Section 24 registration numbers associated with the active ingredient fomesafen. Of these, 5 were end-use products, 4 were technicals or formulation intermediates (with no associated crops), and 11 were state-specific special local needs (Sec. 24c), all of which were associated with a single parent Section 3 label. Only 2 registrants (Syngenta and BASF) hold current fomesafen registrations, and as of this writing, BASF has submitted a Request for Voluntary Cancellation for its fomesafen containing products.  Three of the end-use products include a second active ingredient.

Table   SEQ Table \* ARABIC  2   Current Fomesafen Registrations

Product Name

(Registrant)	EPA Registration Number

(latest label date)	Active Ingredients

(% w/w)	Crops

Section 3 End Use Products

Reflex

(Syngenta)

Emulsifiable concentrate	100-993

(02/08/08)	Fomesafen 22.8%	Cotton, dry beans, snap beans, soybeans

Flexstar

(Syngenta)

Emulsifiable concentrate	100-1101

(03/20/07)	Fomesafen 22.1%	Soybeans

Prefix

(Syngenta)

Emulsifiable concentrate	100-1268

(4/13/07)	Fomesafen 10.2%

s-metolachlor 46.4%	Soybeans

BAS 530 04

(BASF)

Soluble concentrate	7969-82

10/22/97	Fomesafen 12.9%

Bentazon 29%	Soybeans

Faster

(BASF)

Soluble concentrate	7969-83

10/22/97	Fomesafen 7.2%

Bentazon 29.8%	Soybeans

Section 24 Registrations

Reflex

(Syngenta)

Emulsifiable concentrate	AL030003 AR030006 GA880005 MS980002 NC950010 SC030006 TX040002	Fomesafen 22.8%	Pine seedlings in nurseries

	NC870005

SC900004

Soybeans, idle cropland

	SC900004

Soybeans, idle cropland, non cropland

(USDA eradication program only)

	NE060002

Dry beans

	AR080004

Cotton

Section 3 Technicals and Formulation Intermediates

Fomesafen paste	100-1016	Manufacturing intermediates with no registered crop uses.  Not anticipated to be environmentally relevant except in case of spill.

Fomesafen technical	100-1017

	Fomesafen salt aqueous concentrate	100-1092

100-1103

2.5	Assessment Endpoints

Assessment endpoints are selected based on ecosystems typically at risk from pesticide applications.  Specific ecological effects are evaluated based on toxicity information from guideline tests and open literature data, and focus on the general categories of survival, growth, and reproduction.  Information regarding sub-lethal effects, if available, is discussed in the risk characterization.  EFED assesses behavioral or biochemical endpoints if they are quantitatively linked to effects on survival or fecundity.

Table   SEQ Table \* ARABIC  3   Summary of Assessment Endpoints and Measures of Ecological Effect

Assessment Endpoint	Measures of Ecological Effecta

Aquatic Environments

1.  Survival, growth, and reproduction of fish and aquatic phase amphibians	Freshwater

1a.  Rainbow trout acute LC501

1b.  NOAEC estimated from sheepshead minnow ACR1

Saltwater

1c.  Sheepshead minnow acute LC501

1d.  Sheepshead minnow chronic NOAEC

2.  Survival, growth, and reproduction of aquatic invertebrates Freshwater

2a.  Water flea EC501

2b.  Water flea chronic NOAEC1

Saltwater

2c.  Mysid shrimp acute EC501

2d.  Mysid shrimp chronic NOAEC1

3.  Survival, growth, and reproduction of aquatic plants	Freshwater

3a.  Non-vascular plant (freshwater algae) acute EC501 and NOAEC1

3b.  Non-vascular plant (freshwater algae) acute EC502 and NOAEC

Saltwater

3c.  Non-vascular plant (saltwater diatom) acute EC502 and NOAEC3

Terrestrial Environments

4.  Survival, growth, and reproduction of mammals	4a.  Guinea pig acute LC501

4b.  Rat chronic NOAEC1

5.  Survival, growth, and reproduction of birds, terrestrial phase amphibians, and reptiles	5a.  Mallard duck acute oral LC501

5b.  Mallard duck acute dietary LC501

5c.  Mallard duck chronic NOAEC1

6.  Survival, growth, and reproduction of terrestrial invertebrates	6a.  Honey bee acute contact LC50

7.  Survival, growth, and reproduction of terrestrial plants	7a.  Monocot (onion) seedling emergence EC251

7b.  Dicot (radish) vegetative vigor EC251

a  All toxicity data reviewed for this assessment are tabulated in Appendix B.

1  Guideline study

2  ECOTOX study

2.5.1	Ecosystems Potentially at Risk

For typical fomesafen applications, the ecosystem at risk is the application site itself, including organisms that might be sprayed during application, organisms affected by residual fomesafen in the soil; and the adjacent aquatic and terrestrial environments affected due to runoff, spray drift, or groundwater contamination.  In water bodies receiving runoff from the treatment site, fish, aquatic-phase amphibians, aquatic invertebrates, and aquatic vascular and non-vascular plants are considered.  Terrestrial organisms assessed include non-target plants, insects, amphibians, reptiles, birds, and mammals.  Because fomesafen is an herbicide, potential affects on non-target plants have been addressed at length.

2.5.2	Ecological Effects

Evaluation of ecological effects focuses initially on direct effects to the groups of organisms residing in the ecosystems at risk, based on ratios (risk quotients) of the estimated environmental concentration (EEC) to a designated toxicity endpoint for a surrogate test organism.  If pre-established levels of concern (LOCs) are exceeded for direct effects, indirect effects to endangered species (e.g., food chain, decrease in community diversity) are evaluated based on the group of organisms exceeding the LOC.  Details on the RQ method and LOCs are in Appendix G.

<IP_ADDRESS>	Direct

Direct effects evaluated are the survival, growth, and reproduction of various taxa of organisms potentially exposed to fomesafen.  Taxonomic groups evaluated include aquatic plants (algae and vascular), aquatic invertebrates, aquatic vertebrates, terrestrial plants, terrestrial invertebrates, birds, and mammals.  There are currently no guideline tests for reptiles or amphibians, so these taxa are evaluated using bird data as a surrogate for reptiles and terrestrial phase amphibians, and fish as a surrogate for aquatic phase amphibians.  Both acute and chronic effects are considered.

<IP_ADDRESS>	Indirect

When herbicides are applied, indirect effects may include a decline in primary productivity, or change in composition of plant communities proximate to the treated area or systems (wetlands and water bodies) receiving runoff from the site.  If LOCs are exceeded for any taxa, potential indirect effects to endangered species are assessed.

 Figure   SEQ Figure \* ARABIC  2   Conceptual model for fomesafen effects2.6	Risk Hypotheses

(	Fomesafen transported in runoff from treated areas may affect the survival, growth, or reproduction of aquatic plants, aquatic invertebrates, aquatic-phase amphibians or fish.

(	Fomesafen may affect the survival, growth, or reproduction of non-target plants proximate to the treatment site.

(	Fomesafen residues in plant and animal dietary sources may affect growth, survival, or fecundity of birds, terrestrial-phase amphibians, or small mammals ingesting these materials.

(	Fomesafen residues on plants may affect survival of terrestrial invertebrates.

2.7	Results of Previous Assessments

A Section 3 new use ecological risk assessment was conducted for fomesafen in 2006 (DP302766) when it was proposed for use on cotton, dry beans, and snap beans.  Two proposed rates (0.5 lb ai/A, ground only) and 0.375 lb ai/A (ground and aerial) were evaluated.  An alternative lower rate (0.2 lb ai/A) was also evaluated.

Key findings of this assessment included:

(	The greatest acute risk associated with fomesafen use was for non-target terrestrial plants.

(	The persistence and mobility of fomesafen in soil and the persistence in aquatic environments is a concern.

(	Accumulation in the soil of a field repeatedly treated with fomesafen may adversely affect crops subsequently planted in the field.  Effects from a single treatment may persist for 3-18 months.

(	Concentrations of fomesafen in shallow groundwater used for irrigation purposes may be high enough to adversely affect crops subsequently planted in the field.

(	Fomesafen is practically non-toxic to slightly toxic to aquatic animals, both freshwater and estuarine/marine.  No adverse effects to aquatic animals are anticipated based on proposed application rates.

(	Fomesafen does exert toxic effects on aquatic plants but risk quotients (RQs) for the scenarios modeled were below the level of concern (LOC).

(	Fomesafen is practically non-toxic to slightly toxic to birds and mammals on an acute basis.  Chronic reproductive effects were noted in rats.  A chronic LOAEC for birds was not established.  No acute risk LOCs were exceeded, but acute endangered species LOCs were exceeded for small mammals at application rates of 0.5 and 0.375 lb ai/A.  Some chronic RQs for both birds and mammals exceeded the LOC at all application rates.  The meaning of the exceedence for birds is uncertain, as the guideline study submitted did not determine a LOAEC.  Better data may significantly affect the chronic risk picture for birds.

Endangered Species

(	Based on LOC exceedences, the following taxa of endangered species were identified as potentially being at risk from fomesafen use: amphibians (terrestrial phase), birds, dicotyledon plants, mammals, monocotyledon plants, and reptiles

(	Fomesafen is likely to affect plants near the treated areas, with potential effects extending to >900 ft away from the treatment source in the case of aerial application.  Direct effects (reduction of growth, survival, or fecundity) may occur for endangered plants in the drift zone.  Effects on non-endangered plants in the drift zone may constitute indirect effects (reduction of food or cover) to endangered animals.

Fomesafen was registered for use on all proposed crops, with a maximum application of 0.375 lb ai/A via both aerial and ground applications.

2.8	Analysis Plan

This assessment was conducted in accordance with the methods, and using the models described in the Overview Document (USEPA 2004).  Some additional methods were used to more specifically determine which listed species might be at risk as a result of fomesafen use.  These methods build on existing models and were as follows:

●	Terrestrial animals were grouped into “Kenaga categories” based on diet and size information available in the natureserve database (  HYPERLINK "http://www.natureserve.org"  www.natureserve.org ) and species recovery plans developed by the Services in order to determine which animals were likely to be at risk.

●	The AgDrift model was used to determine how far away from the point of application that estimated fomesafen concentrations on terrestrial food items were high enough for RQs to exceed LOCs.  The point at which the concentration is low enough that the RQ drops below the LOC is referred to as the “clearance estimate” and is presented in the appropriate tables.

3.0	Exposure Assessment

EFED conducted the exposure assessment using standard exposure modeling methods, as described in the Overview Document (USEPA 2004).

3.1	Label Application Rates and Intervals

Fomesafen is registered under Section 3 as a pre-plant, pre-emergence, and post-emergence herbicide for control of broadleaf weeds, grasses, and sedges in soybeans, cotton, snap beans, and dry beans.  Additional uses covered under Section 24c (special local needs, or SLN) registrations are for use on pine seedlings in nurseries (AL, AR, GA, MS, NC, SC, TX), for control of weeds in dry beans in Nebraska, and for control of witchweed in soybeans and idle cropland in North Carolina and South Carolina.  Use in South Carolina also includes non-cropland, although the South Carolina uses are limited to areas included in the USDA witchweed eradication program.

Section 3 labels belonging to the primary registrant, Syngenta, include regionally specific application rates, shown in Table 1.  Based on these labels, fomesafen can be applied via aerial and ground spray at a maximum application rate of 0.375 lbs ai/A.  Section 3 labels belonging to BASF do not provide regionally specific application rates, but “are intended for use” in the areas included in Regions 1-4, and application rates (0.19- 0.23 lb ai/A) are lower than those on the Syngenta labels.

Table   SEQ Table \* ARABIC  4   Label Application Rates and Intervals for Fomesafen Use on Soybeans, Cotton, Snap Beans and Dry Beans1

Region	States in Region	App Rate (lbs/A)	Application Interval

1	AL, AR, GA, LA, MS, MO2, NC, OK2, SC, TN, TX2	0.375	1 year

2	DC, DE, IL2, IN2, KY, MD, , OH2, PA3, WV, VA, 	0.375	2 year

3	CT, IA, ME, MA, MI3, NH, NJ, NY, PA3, RI, WI, VT	0.312	2 year

4	KS2, MI3, MN2, ND3, NE2 SD3, WI2	0.25	2 year

5	ND3, MN3, SD3	0.170	2 year

1REFLEX 2.5 Gallon( (EPA Reg. No. 100-993)

2Does not include entire state

3Portions of state are in multiple regions

Application rates on some of the Section 24c labels (pine seedling use, also belonging to the primary registrant) are slightly higher, with a maximum application rate of 0.5 lbs ai/A for pre-emergence applications.  The higher rate does not apply in all states.  States included under pine seedling uses are in Region 1 as defined on the parent label, although the Section 24c label for Texas is assumed to include the entire state.

Table   SEQ Table \* ARABIC  5   Label Application Rates and Intervals for Section 24c Uses of Fomesafen

Use Site	States	Application Technique	Max App Rate (lbs ai/A) Application Interval

Pine seedlings in nurseries	AR, GA, MS, NC, SC,	Aerial or Ground 	0.5	1 year

	AL, TX	Aerial or Ground	0.375	1 year

Soybeans, idle cropland, non-cropland	SC (Horry and Marion counties) Aerial or Ground	0.375	1 year

Soybeans, idle cropland	NC (Robeson, Cumberland, Sampson, Bladen, and Pender counties)	Aerial or Ground	0.375	1 year

Dry beans	NE	Aerial or Ground	0.25	2 years

1 Based on areas currently infested with witchweed, as noted on   HYPERLINK "http://www.ncagr.com/plantindustry/plant/weed/witchnc.htm"  www.ncagr.com/plantindustry/plant/weed/witchnc.htm , accessed May 16, 2008

3.2	Aquatic Exposure

Tier II EFED aquatic exposure modeling uses the linked Pesticide Root Zone Model and Exposure Analysis Model System (PRZM/EXAMS).  PRZM uses the chemical’s physical and environmental fate properties and the site characteristics to predict the concentration of pesticide in runoff and entrained sediment from the field.  EXAMS estimates the concentration of pesticide in an edge-of-field small water-body receiving runoff from the field.  The water-body has a constant volume (20 million liters) with no outflow and is intended to represent an upper-end occurrence concentration.

3.2.1	PRZM-EXAMS Modeling Inputs and Scenario Selection

The aquatic exposure assessment for fomesafen was conducted to assess use on soybeans, dry beans, snap beans, and cotton. The Mississippi soybeans scenario was used as both a scenario representing MS soybeans as well as a surrogate for dry beans and snap beans, as EFED currently has no standard scenarios for these crops in this region. Standard scenarios were selected to assess runoff potential from vulnerable use sites in MS (soybean and cotton), NC (cotton), and TX (cotton). The MI beans scenario from region 4 was selected to provide more geographical balance to the analysis since all of the other scenarios occur in region 1. No other EFED scenarios had combinations of crop and location relevant to this assessment. Input parameters for fomesafen were selected according to EFED Input Parameter Guidance for PRZM/EXAMS1. Input parameters are shown in   REF _Ref210113708 \h  \* MERGEFORMAT  Table 6 .

Table   SEQ Table \* ARABIC  6 .  Input Parameters for PRZM-EXAMS Modeling of Fomesafen on Cotton, Soybeans, Dry Beans, and Snap Bean

Parameter	Value	Comments	Source

Application Rates (kg ai/ha)	0.19 - 0.56	Varies by Region	Label1

Molecular Weight (grams/mole)	420

EPA 2020220

Solubility (mg/L)	1200	@pH = 7; 200c	MRID 45048207

Vapor Pressure (torr)	<7.5 × 10-7	@ 50oC	HSDB

Henry’s Constant (atm m3/mol) 	7.5 × 10-13	Estimated	HSDB

Kd (L/kg)	0.68	Lowest non-sand Kd	Acc. No. 259413

Aerobic Soil Metabolism Half-life (days)	511	Upper 90th percentile of mean2	Acc. No. 071059

Acc. No. 00135660

Aerobic Aquatic Metabolism Half-life (days)	129.4	Upper 90th percentile of mean3	Acc. No. 72158

Anaerobic Aquatic Metabolism Half-life (days)	1000	Conservative Assumption 	No Data Available

Photodegradation in Water (days)	289	@pH = 7	MRID 40451101

Hydrolysis Half-life (days)	Stable	@pH = 7	Acc. No. 071059

1 Reflect application rates on the REFLEX 2LC, REFLEX 2.5, and REFLEX labels

2 Calculated from half-lives of 187.6, 630, 57, 693, 349.3, 527.1, 207 days using a mean of 387.84 days and standard deviation of 242.90 days.

3 Calculated from half-lives of 139.9, 60.9, 92.4, and 115.5 days using a mean of 102 days and standard deviation of 33.44 days.

The MI beans scenario from region 4 was selected to provide more geographical balance to the analysis since all of the other scenarios occur in region 1. No other EFED scenarios had combinations of crop and location relevant to this assessment. Because applications in Region 4 are restricted to every other year, a modified copy of the PE5 shell was created to only apply the pesticide in alternate years (odd years). This can be seen in the Appendix A PRZM/EXAMS outputs for Michigan beans in which the even year EECs are always lower than the odd years.

3.2.2	PRZM-EXAMS Modeling Output

For aerial applications (  REF _Ref210113803 \h  \* MERGEFORMAT  Table 7 ), peak 1 in 10 year estimated environmental concentrations (EECs) ranged from 2.3 ppb (beans, MI) to 12.0 ppb (cotton, TX). Chronic 1-in-10 year (21-day average and 60-day average) EECs ranged from 1.7 ppb (beans, MI, 60-day average) to 11.4 ppb (cotton, MS &TX, 21-day average).

Table   SEQ Table \* ARABIC  7 .  PRZM-EXAMS Aquatic EECs for Fomesafen

Region	Crop	State	App. Date 	Aerial/ Ground 	Peak	21 days	60 days

	(g/L (ppb)

Region 1: Annual Applications at 0.375 lb a.i/A

1	Soybean	MS	5/1	A	8.99	8.57	7.74

G	8.19	7.77	6.95

1	Cotton	MS	5/15	A	11.83	11.37	10.07

G	11.20	10.79	9.56

1	Cotton	NC	5/10	A	8.99	8.72	8.03

G	8.20	7.96	7.34

1	Cotton	TX	5/10	A	11.96	11.39	10.31

G	11.44	10.90	9.85

Region 4: Every-other-year Applications at 0.28 lb a.i/A

4	Beans	MI	6/15	A	2.27	2.15	1.94

G	2.37	2.25	2.02

Peak 1-in-10 year EECs for ground spray applications (  REF _Ref204412645 \h  \* MERGEFORMAT  Table 8 ) ranged from 10.9 ppb (cotton, NC) to 15.3 ppb (cotton, TX).  Chronic 1 in 10 year (21-day average and 60-day average) concentrations ranged from 9.8 ppb (cotton, NC, 60-day average) to 14.5 ppb (cotton, TX, 21-day average).

Table   SEQ Table \* ARABIC  8   PRZM-EXAMS EECs for Fomesafen at 0.50 lb ai/A

Region	Crop	State	App. Date	Peak	21 days	60 days

(g/L

1	Cotton	MS	5/15	14.9	14.4	12.7

1	Cotton	NC	5/10	10.9	10.6	9.8

1	Cotton	TX	5/10	15.3	14.5	13.1

1- Concentrations were derived for 0.50 lb ai/A using ground spray

3.2.3	Registrant-submitted Aquatic Exposure Modeling

The registrant submitted Tier II PRZM/EXAMS modeling assessments for fomesafen use on cotton and soybeans (MRID 450482-04, 450482-05, 450482-06).  The modeling scenarios used were developed to assess fomesafen runoff from vulnerable use sites (Hydrologic D soils) with high rainfall.  Selected scenarios represent sites in Tensas County, LA (MRLA 131) for cotton; Leflore, MS (MRLA 131) for soybeans; and Dodge, NE (MRLA 102B) for soybeans, and Sheboygan, WI (MRLA 95B).  Maximum application rates were 0.31 lbs for snap beans, 0.5 lbs ai/A for cotton, and 0.375 lbs ai/A for soybeans.  Only ground spray was considered, although the labels allow aerial spray.  The sources (study identification numbers) of environmental fate data are not reported.  Additionally, there are no explanations for selection of the environmental fate data in the exposure assessment.  The registrant estimated environmental concentrations are similar in magnitude to, but slightly higher than, those calculated by EFED.

3.2.4	SCIGROW Modeling for Ground Water

Because fomesafen is mobile and persistent in soil, a screening level groundwater assessment using SCIGROW (ver. 2.3) was conducted to estimate the concentration of fomesafen in shallow groundwater, which could potentially be used for crop irrigation.  Input parameters for SCIGROW are listed in Table 10.

Table   SEQ Table \* ARABIC  9 .  Input Parameters for SCIGROW Modeling for Fomesafen

Parameter	Value	Comments	Source

Application Rate (kg ai/ha)- Cotton	0.375 – 0.17	Varies by Region Label1

Koc (L/kg)	68	Estimated2	Acc No. 259413

Aerobic Soil Metabolism Half-life (days)	387.84	Mean3	Acc No. 071059

Acc. No. 00135660

1-Reflect maximum application rates on the REFLEX 2LC, REFLEX 2.5 and REFLEX labels

2-Koc estimated using Kd/SOC=Koc; where Kd=0.68 and SOC=1% SOC percentage

3-Calculated from half-lives of 187.6, 630, 57, 693, 349.3, 527.1, 207 days using a mean of 387.84 days and standard deviation of 242.90 days.

Based on the SCIGROW estimate, the concentration of fomesafen in shallow ground water in sand soils (  REF _Ref221071702 \h  \* MERGEFORMAT  Table 10 ) is not expected to exceed 5.01 (g/L (Region 1).

Table   SEQ Table \* ARABIC  10  Label Application Rates and Intervals for Fomesafen Use on Soybeans, Cotton, Snap Beans, and Dry Beans1

Region	Application Rate (lbs/A)

(Application Interval)	SCIGROW-estimated Groundwater Concentrations (µg/L)	Fomesafen Application Due Solely to Irrigation (lbs ai/A)

1	0.375 (1 year)	5.01	2.27 × 10-3

2	0.375 (2 year)	2.5	1.13 × 10-3

3	0.312 (2 year)	2.08	9.42 × 10-4

4	0.25 (2 year)	1.67	7.56 × 10-4

5	0.17 (2 year)	1.14	5.16 × 10-4

1REFLEX 2.5 Gallon( (EPA Reg. No. 100-993)

Because fomesafen is expected to leach to groundwater, EFED has calculated the maximum application rate of fomesafen from two inches of irrigation water. This calculation assumes that two inches of irrigation water is required for optimum plant growth.  The application rate of fomesafen in terms of lbs ai/A in 2 inches of groundwater is calculated as follows:

where:

fomesafen is the estimated application rate of fomesafen in lbs ai/A in 2 in/A of groundwater; and

EEC is the region-specific SCIGROW EEC in groundwater from Table 5.

Based on two inches of irrigation and the SCIGROW estimate, the application rate of fomesafen is estimated to vary from 0.00227 to 0.000516 lbs ai/A.

3.2.5	Soil Accumulation

Because of the persistence of fomesafen in soil, a screening level assessment was conducted to quantify the accumulation of fomesafen residues in soil.  This screening-level assessment does not consider loss of pesticide to run-off and leaching (only degradation by aerobic soil metabolism is considered). A first-order decay model was used to estimate fomesafen soil concentrations over 20 years. This model is based on first-order decay of a single application:

where: A is the soil fomesafen concentration at any point in time; A0 is the original soil fomesafen concentration at the time that it was applied; k is the upper 90th percentile of the mean aerobic soil metabolism half-life (t1/2 = 511 days; k = 1.356452 × 10-3 days-1), which was used to represent the microbial mediated decay rate of fomesafen in soil; and t is the time since the fomesafen application.

Because multiple applications occur over this 20 year timeframe, this equation is modified to account for multiple applications:

where: i is a counter variable that denotes the first fomesafen application when i = 1 and the second when i = 2, etc.; n is the last application; A0,i is the soil fomesafen concentration contributed by the ith application; and ti is the time since the ith fomesafen application.

The soil fomesafen concentration contributed to the upper 15 cm of soil by the ith application (A0,i) in mg/Kg is calculated as:

where: AppRate is the regional maximum application rate from Table 3 and density is the bulk density of soil. The bulk density of soil varies from 1.0 g/cm3 for clay soils to 1.8 g/cm3 for sandy or compacted soils (  HYPERLINK "http://www.cdpr.ca.gov/docs/emon/pubs/sops/fsso001.pdf"  http://www.cdpr.ca.gov/docs/emon/pubs/sops/fsso001.pdf ). The modeling scenario assumes that 100% of fomesafen residue is applied to the soil as recommended for a pre-emergent application.  The model scenario also assumes that microbial degradation is the only route of dissipation from the application site. These assumptions are expected to exaggerate predicted formesafen soil concentrations.

  REF _Ref221072091 \h  \* MERGEFORMAT  Figure 3  illustrates the fomesafen concentrations in soil reach a plateau after approximately 10 years regardless of the application rate or soil bulk density.  An application rate of 0.375 lbs/A applied every year (Region 1) can theoretically result in a maximum fomesafen concentration of 0.71 mg/kg in soils with a low bulk density (1.0 g/cm3).  The same application rate (0.375 lbs ai/A applied every year) can theoretically result in a maximum fomesafen concentration of 0.4 mg/kg in soils with a high bulk density (1.8 g/cm3). Applying fomesafen every other year (Region 2 to 5) and at lower application rates also reduces residual soil fomesafen concentrations.

Figure   SEQ Figure \* ARABIC  3 . Estimate of Fomesafen Loading in the Surface Soil (0-15 cm depth) in Clay Soils (a; bulk density = 1.0 g/cm3) and Sandy or Compacted Soils (b; bulk density = 1.8 g/cm3) of Regions 1 through 5.

3.3	National Surface Water Monitoring Data

3.3.1	Surface Water

The USGS National Water Quality Assessment (NAWQA) database was accessed (6/9/08, SPW).  No data for fomesafen was located in the database, but this appears to be because fomesafen is not included in the schedules of chemicals quantified by the laboratory.  Therefore, a lack of data should not be construed as meaning there are no detectable fomesafen residues in surface waters.

3.3.2	Ground Water

g/L (at 4 months) to 17g/L (at 1 month).  It was detected at a concentration of 1 g/L in the medium- to deep-depth wells.

These observed porewater concentrations are much higher than the SCIGROW EECs for groundwater. Using the porewater concentrations of 1 mg/L and 17mg/L (from the groundwater study) as outer bounds of the fomesafen groundwater concentrations that might be applied in irrigation water, concentrations of fomesafen in irrigation water could range from 0.45 to 7.7 lbs ai/A, respectively.

3.4	Bird and Mammal Exposure (TREX)

EFED estimates exposure of birds and mammals using the Terrestrial Exposure Model (TREX).  TREX uses the Kenaga nomagram, as modified by Fletcher et al (1994) to determine pesticide residues on several categories of food items, then calculates the potential dose an organism might receive from ingesting contaminated items using allometric equations.  Dose estimates are based on the upper bound dose and assumptions that the organism exclusively eats one type of food item and forages only in the treated and/or overspray areas.

Table   SEQ Table \* ARABIC  11   Input Parameters for TREX Modeling

Input Parameters	Value	Source

Application Rate	0.5 lb ai/A

0.375 lb ai/A

0.312 lb ai/A

0.25 lb ai/A

0.17 lb ai/A	Label

Reflex

100-993

Foliar Half-life	35 days	EFED Default

Number of Applications	1 per year	Label

Reflex

100-993

Avian LD50	5,000 mg/kg bw (mallard duck)	MRID 163168

Avian LC50	20,000 mg/kg diet (mallard duck)	MRID 163381

Avian NOAEC	46 mg/kg diet (mallard duck)	MRID 135639

Mammal LD50	607 mg/kg bw (guinea pig)	MRID 164901

Mammal NOAEC	1,000 mg/kd diet (rat)	MRID 144862

For birds, dose estimates for the 0.50 lb ai/A application rate range from 2.1 mg/kg bwt (1000 g frugivores, granivores, and insectivores) to 134.0 mg/kg bwt (20 g herbivores).  At the 0.375 lb ai/A application rate, estimated doses range from 1.6 mg/kg bwt (1000 g frugivores, granivores, and insectivores) to 102.5 mg/kg bwt (1000 g fruit and pods).  Dose estimates for the 0.17 lb ai/A application rate range from 0.7 mg/kg bwt (1000 g frugivores, granivores, and insectivores) to 46.5 mg/kg bwt (20 g herbivores).

Table   SEQ Table \* ARABIC  12   Bird Dose Estimates

Feeding Categories	Kenaga Upper Bound Dose (mg/kg bwt)

	Small

(20 g)	Medium

(100 g)	Large

(1000 g)

0.50 lb ai/A Application Rate(pine seedlings, Region 1)

Short grass	133.93	76.38	34.19

Tall grass	61.39	35.01	15.67

Broadleaf plants/small insects	75.34	42.96 	19.23

Fruits/pods/seeds/large insects	8.37	4.77	2.14

0.375 lb ai/A Application Rate (Region 1 & 2)

Short grass	102.5	58.45	26.17

Tall grass	46.98	26.79	11.99

Broadleaf plants/small insects	57.66	32.88	14.72

Fruits/pods/seeds/large insects	6.41	3.65	1.64

0.17 lb ai/A Application Rate (Lowest Rate, Region 5)

Short grass	46.47	26.50	11.86

Tall grass	21.30	12.14	5.44

Broadleaf plants/small insects	26.14	14.90	6.67

Fruits/pods/seeds/large insects	2.90	1.66	0.74

For mammals dose estimates for the 0.50 lb ai/A application rate range from 0.25 mg/kg bwt (1000 g granivore) to 112 mg/kg bwt (20 g short grass).  At the 0.375 lb ai/A application rate, estimated doses range from 0.2 mg/kg bwt (1000 g granivore) to 85.8 mg/kg bwt (20 g short grass).  Dose estimates for the 0.17 lb ai/A application rate range from 0.1 mg/kg bwt (1000 g granivore) to 38.9 mg/kg bwt (20 g short grass).

Table   SEQ Table \* ARABIC  13   Mammal Dose Estimates

Feeding Categories	Kenaga Upper Bound Dose (mg/kg bwt)

	Small

(15 g)	Medium

(35 g)	Large

(1000 g)

0.50 lb ai/A Application Rat e(Pine seedlings, Region 1)

Herbivores/Insectivores

Short grass	112.12	77.49	17.97

Tall grass	51.39	35.52	8.23

Broadleaf plants/small insects	63.07	43.59	10.11

Fruits/pods/seeds/large insects	7.01	4.84	1.12

Granivores

Fruits/pods/seeds/large insects	1.56	1.08	0.25

0.375 lb ai/A Application Rate (Region 1,2)

Herbivores/Insectivores

Short grass	85.81	59.30	13.75

Tall grass	39.33	27.18	6.30

Broadleaf plants/small insects	48.27	33.36	7.73

Fruits/pods/seeds/large insects	5.36	3.71	0.86

Granivores

Fruits/pods/seeds/large insects	1.19	0.82	0.19

0.17 lb ai/A Application Rate (Lowest Rate, Region 5)

Herbivores/Insectivores

Short grass	38.90	26.88	6.23

Tall grass	17.83	12.32	2.86

Broadleaf plants/small insects	21.88	15.12	3.51

Fruits/pods/seeds/large insects	2.43	1.68	0.39

Granivores

Fruits/pods/seeds/large insects	0.54	0.37	0.09

3.5	Terrestrial Invertebrate Exposure

g ai/g insect.  The fomesafen residue for a bee (µg ai/bee) is calculated by multiplying the residue by the assumed weight of a honey bee (0.128 g) to establish a dose per bee.  This method assumes that contact is the relevant route of exposure, rather than ingestion.  This method of estimation is believed to be adequate for fomesafen.

Table   SEQ Table \* ARABIC  14   Terrestrial Invertebrate Exposure

Application Rate

(lb ai/A)	Insect Size Category	EECs

(mg ai/kg insect)	Dose per Bee

(g ai/bee)

0.50

(Pine seedlings, Region 1)	Small insects	67.50	8.64

	Large insects	7.50	0.96

0.375

(Regions 1,2)	Small insects	50.63	6.48

	Large insects	5.63	0.72

0.017

(Region 5)	Small insects	22.95	2.94

	Large insects	2.55	0.32

3.6	Terrestrial Plant Exposure (TerrPlant & AgDrift)

Currently, EFED uses the TerrPlant Model (Version 1.2.1) to evaluate exposure of terrestrial plants to pesticides applied on agricultural fields.  In cases where spray drift may be of concern in the risk assessment EFED also uses the AgDrift model.

3.6.1	TerrPlant

TerrPlant has two basic exposure scenarios.  The first is an adjacent upland area, which is exposed to the pesticide via drift and dissolved concentrations in sheet runoff.  The second is an adjacent semi-aquatic (wetland) area, which is exposed to the pesticide via drift and to dissolved concentrations in channelized runoff.  Drift is calculated as a percentage of the application rate (1% for ground and 5% for aerial, airblast, or spray chemigation) and is not adjusted for distance from the application site.  The amount of dissolved pesticide in the runoff component is estimated based on solubility of the active ingredient.

Table   SEQ Table \* ARABIC  15   Terrestrial Plant Exposure

Application Method	Total Loading (Runoff + Drift) (lb ai/A)	Drift EEC (lb ai/A)

	Upland Areas	Wetland Areas	All Areas

Application Rate 0.5 lb ai/A (Pine seedlings, Region 1)

Aerial	0.05	0.275	0.025

Ground	0.03	0.255	0.005

Application Rate 0.375 lb ai/A (Region 1 & 2)

Aerial	0.0375	0.20625	0.01875

Ground	0.0225	0.19125	0.00375

Application Rate 0.312 lb ai/A (Region 3)

Aerial	0.0312	0.1716	0.0156

Ground	0.01872	0.15912	0.00312

Application Rate 0.25 lb ai/A (Region 4)

Aerial	0.025	0.1375	0.0125

Ground	0.015	0.1275	0.0025

Application Rate 0.17 lb ai/A (Region 5)

Aerial	0.017	0.0935	0.0085

Ground	0.0102	0.0867	0.0017

3.6.2	AgDrift

Because of concerns about effects on non-target plants located in the overspray or spray drift area, EFED elected to perform an analysis of potential deposition of fomesafen using AgDrift modeling software.  AgDrift was developed using extensive field-measured data sets, and provides a method of estimating deposition of the compound of concern at a specified distance away from the application source.  Deposition is heavily dependent on the method of application and droplet size.

The AgDrift modeling reported in   REF _Ref217197768 \h  Table 16  and   REF _Ref217197829 \h  Table 17  is AgDrift Tier I, with associated defaults.  It should be completely reproducible by anyone else using the model with the same settings, as the only required inputs are the application rate and distance from the field.  Please note, however, that “fraction of applied” results were put

 into an Excel spreadsheet in order to more efficiently calculate RQs for different endpoints and application rates.  Some of the values being calculated are based on very low concentrations of fomesafen, and there could be minor variations in output depending on how values for the input or from the output are rounded.

 The Tier I modeling extends to approximately 1,000 ft away from the point of application.  At this point, the mathematical curve that represents the deposition is asymptotic.  Thus, evaluations past this point were not performed.  It is possible to estimate deposition at longer distances using higher tiers of AgDrift, but the greater distances add substantial uncertainty.  For aerial applications, the deposition at 950 ft ranges from 0.3% to 4%, depending on droplet size.  Deposition was estimated in 50 ft increments for droplet spectrums ranging from very fine to very coarse (ASTM standard designation, 4 different ranges as implemented in the modeling software).  For ground applications, estimates were done every 10 ft for the first 100 ft and at 50 ft increments thereafter.  Estimates were done for both high and low boom application methods, in the 2 droplet ranges implemented in AgDrift (very fine to fine, fine to medium, ASTM standard designation).  All values reported are based on the 90th percentile estimate.  Complete modeling output is included in Appendix G.

Values in the table are reported at the distance where deposition is slightly lower than the NOAEC for the most sensitive plant, or at the limit of the Tier I modeling, designated as >950 ft.  The actual furthest extent of the Tier I model varies slightly depends on the method of application and droplet size.

Table   SEQ Table \* ARABIC  16   Drift Deposition from Ground Applications

Application Rate

(lb ai/A)	Low Boom	High Boom

	Very Fine to Fine	Fine to Medium	Medium to Coarse	Coarse to Very Coarse

	Distance

(ft)	Deposition

(lb ai/A)	Distance

(ft)	Deposition

(lb ai/A)	Distance

(ft)	Deposition

(lb ai/A)	Distance

(ft)	Deposition

(lb ai/A)

0.5	300	0.0018	150	0.0017	450	0.0020	250	0.0017

0.375	200	0.0019	80	0.0020	400	0.0020	150	0.0019

0.312	200	0.0016	70	0.0020	350	0.0019	150	0.0016

0.25	150	0.0017	50	0.0019	300	0.0019	90	0.0019

0.17	80	0.0020	30	0.0019	250	0.0016	60	0.0018

Table   SEQ Table \* ARABIC  17   Drift Depostion from Aerial Applications

Application Rate

(lb ai/A)	Very Fine to Fine	Fine to Medium	Medium to Coarse	Coarse to Very Coarse

	Distance

(ft)	Deposition

(lb ai/A)	Distance

(ft)	Deposition

(lb ai/A)	Distance

(ft)	Deposition

(lb ai/A)	Distance

(ft)	Deposition

(lb ai/A)

0.5	950	0.0214	950	0.0060	950	0.0028	700	0.0020

0.375	950	0.0161	950	0.0045	950	0.0021	550	0.0019

0.312	950	0.0134	950	0.0037	950	0.0021	550	0.0019

0.25	950	0.0107	950	0.0030 	600	0.0019	350	0.0020

0.17	950	0.0073	950	0.0020	400	0.0019	250	0.0019

4.0	Effects Assessment

Toxicity endpoints are established based on data generated from guideline studies submitted by the registrant, and from open literature studies that meet the criteria for inclusion into the ECOTOX database maintained by EPA/ORD.  EFED policy is to use the effects endpoint from the most sensitive tested species for each taxa evaluated.  In aquatic systems, taxa evaluated include aquatic plants, invertebrates, and fish.  Fish serve as a surrogate for aquatic-phase amphibians when amphibian data are unavailable or unacceptable for quantitative use.  Where data are available, separate endpoints are used for freshwater and estuarine/marine organisms.  In terrestrial systems, taxa evaluated include birds and mammals.  Bird endpoints are generally derived from guideline studies on bobwhite quail and/or mallard duck.  Bird data are used as a surrogate for reptiles and terrestrial-phase amphibians when data for these taxa are unavailable or unacceptable for quantitative use.  Mammal data are derived from guideline studies conducted on laboratory rats, mice, or rabbits.

4.1	Specific Toxicological Concerns Associated with this Chemical

Fomesafen is a diphenyl-ether, one of a class of herbicides sometimes referred to as light-dependent peroxidizing herbicides (LDPHs), which have enhanced toxicity in the presence of solar ultra-violet radiation.  Because toxicity of the LDPHs is affected by the presence of ultraviolet (UV) radiation, toxicity tests used in this assessment, which were conducted under standard laboratory lighting conditions, may underestimate the toxicity of fomesafen to some taxa under natural sunlight conditions.  The Agency is currently in the process of developing a protocol for aquatic studies that evaluate the effect of UV light on the toxicity of these herbicides, but at the time of this assessment, it had not been finalized (EFED 2007).  Preliminary studies have been submitted for some chemicals, but not fomesafen.  Fish early life-cycle studies on oxyfluorfen conducted under UV light indicate larval fish LD50s are approximately an order of magnitude lower than LD50s based on standard lighting conditions (MRID 46585104).  In this study, the larval fish appeared to hatch prematurely compared to the controls, and then die.  Based on the mode of action, it is possible that disruption of the egg cell membrane caused the premature hatch.  The extent to which UV light enhances the toxicity of fomesafen is unknown.  However, existing studies may underestimate the toxicity.  Potential impacts of the underestimation are discussed in the Risk Description (Section 6).

Fomesafen, along with other chemicals in this class have been associated with peroxisome proliferation, which can induce hepatocellular carcinomas in rodents.  (Smith and Elcombe 1989, Ashby et al as cited in Krijt et al 1999.  A discussion of potential for carcinogenicity, based on EFED’s review of open literature information and the HED’s review of mammalian guideline studies, is included in the terrestrial effects section.

4.2	Aquatic Hazard Summary

Fomesafen was originally registered for use in the 1980s.  Guideline studies from that time were available for aquatic invertebrates and fish, both freshwater and marine/estuarine.  Although some of the studies were conducted on formulated product, and would not be acceptable under current standards, they were classified as core or supplemental under the guidelines at the time they were submitted, and have been used in this assessment.  When necessary, endpoints for these tests were re-calculated and/or data were converted to express toxicity on the basis of active ingredient.  Overall, fomesafen is slightly toxic to practically nontoxic to invertebrates and practically non-toxic to fish on an acute basis.  Chronic tests were conducted under standard laboratory lighting, and as noted in Section 4.1, may underestimate toxicity by approximately an order of magnitude.

Table   SEQ Table \* ARABIC  18   Aquatic Toxicity Profile for Fomesafen

Assessment Endpoint	Surrogate Species	Toxicity Value Used 	Source Citation	Comments

Freshwater

Acute Toxicity to Fish and Aquatic-phase Amphibians	Rainbow trout LC50=126 mg/L

95%CI=117-135 mg/L

Slope=14.6	MRID

103023	Formulation1,2

(practically nontoxic)

Chronic Toxicity

Fish and Aquatic-phase Amphibians	Calculated based on ACR

(Sheepshead minnow/sheeps-head minnow	LC50=9.4 mg/L

(ACR=13.4)	Estimated	Estimated from formulation data.

Daphnia ACR=7.5

Mysid ACR=35.7

Acute Toxicity to Aquatic Invertebrates	Water flea	LC50=376 mg/L

95%CI=323-437 mg/L

Slope=5.6	MRID 1631169	Formulation1,2

(practically nontoxic)

Chronic Toxicity

Aquatic Invertebrates	Water flea	NOAEC=50 mg/L

LOAEC=100 mg/L	MRID

135642	Formulation1,2

Reduced growth, and # of offspring

Acute Toxicity to Aquatic Plants

(non-vascular)	Green alga	LC50=0.092 mg/L3

NOAEC=0.010 mg/L3	MRID 46673804	Technical

Biomass most sensitive endpoint

Acute Toxicity to Aquatic Plants (vascular)	Duckweed	LC50= 0.210 mg/L

NOAEC=0.064 mg/L	MRID

46673803	Technical

Dry weight most sensitive endpoint

Saltwater

Acute Toxicity to Fish	Sheepshead minnow	LC50= >163mg/L

95%CI=ND

Slope=ND	MRID

135651	Formulation1,2

(practically nontoxic)

Chronic Toxicity to Fish 	Sheepshead minnow	NOAEC=12.2 mg/L

LOAEC=20.1 mg/L	MRID

135644	Formulation1,2

Reduced larval survival

Acute Toxicity to Aquatic Invertebrates	Mysid shrimp	LC50=25 mg/L

95%CI=19-38 mg/L

Slope=ND	MRID

135647	Formulation1,2

(slightly toxic)

Chronic Toxicity

Aquatic Invertebrates	Mysid shrimp	NOAEC=0.70 mg/L

LOAEC=1.7 mg/L	MRID 135648	Formulation1,2

Parental mortality

Acute Toxicity to Aquatic Plants 	SW diatom	LC50= 1.51 mg/L

NOAEC=0.94 mg/L	MRID 46673806	Technical

Biomass most sensitive endpoint

1 Data are from studies originally reviewed and classified in 1984, some of which used formulated product. 2 For purposes of this risk assessment, test concentrations were adjusted for percent ai if necessary, and endpoints were re-calculated using TOXANAL software. 3 Endpoints have been revised since those reported in problem formulation, which were based on provisional data.  ND-not determined.

4.3	Summary of Aquatic Ecotoxicity Studies

4.3.1	Aquatic Guideline Data

Fomesafen was originally registered for use in the 1980s.  Guideline studies from that time were available for aquatic invertebrates and fish, both freshwater and marine/estuarine.  Although some of the studies were conducted on formulated product, and would not be acceptable under current standards, they were classified as core or supplemental under the guidelines at the time they were submitted.  When necessary, endpoints were re-calculated and/or data were converted to express toxicity on the basis of active ingredient. Aquatic plant data are from studies conducted on the technical ingredient.  Acute toxicity (LC50s) for fish and invertebrates ranges from 25 mg ai/L (mysid shrimp, MRID 135647) to 1,507 mg/L (bluegill, MRID 163169).  No sub-lethal effects were reported in the acute studies. Overall, fomesafen is slightly toxic to practically nontoxic to invertebrates and practically non-toxic to fish on an acute basis.  Chronic toxicity (NOAECs) for fish and invertebrates range from 0.7 mg ai/L (mysid shrimp, parental mortality, MRID 1354648) to 50 mg ai/L (Daphnia magna, reduced growth, total number of offspring, MRID 1354642). Because of fomesafen’s low toxicity to aquatic animals based on the available data, additional studies were not requested at the time of problem formulation, and this risk assessment was conducted using existing data.  More recent studies on aquatic plants were conducted on the technical active ingredient (ai).  LC50s for aquatic plants range from 0.092 mg ai/L (green alga, MRID 46673804) to 71 mg ai/L (bluegreen alga, MRID 46673807).  NOAECs range from 0.0095 mg ai/L (green alga, MRID 46673804) to 27.3 mg ai/L (bluegreen alga, MRID 46673807).

4.3.2	Aquatic Data from ECOTOX

Several studies were available in ECOTOX evaluating the effects of fomesafen on aquatic organisms, including mesocosm studies that addressed effects on community structure and primary productivity (Caquet et al 2005 (E87334) and Caquet 2006 (E95935); Perschbacher et al 1997 (E53095)).  Other studies evaluated effects on the hematocytes of snail exposed to fomesafen in solution Russo et al (2007) (E95100) and Russo and Medec (2007) (E95590).

g/L (mean) in the fomesafen-only ponds and as 19.4 ±7.6 g/L (mean) in the fomesafen-Agral 90 ponds.  The authors make no mention of measuring concentrations in other compartments in the mesocosm or performing any mass balance calculations to determine fate of fomesafen in the mixture mesocosms, although they speculate (Caquet et al 2005) it may have accumulated at the interfaces.

Currently, the EFED assumption for spray drift in aerial applications is 5%, and it is assumed to be the product (or whatever application mix) deposited directly on the surface of a water body adjacent to a treated field.  Study authors have essentially made the same assumption, and evaluated the short-term effects (deposition-72 hrs) of a 1% and 10% drift rate associated with aerial application to soybeans on the phytoplankton community of a small (500-L) pond.  Based on this work, one could interpret that short-term effects on the phytoplankton abundance and production from concentrations of fomesafen ≤0.06 mg/L are not anticipated.  This should be caveated with the fact that the community was dominated by cyanobacteria (which appear to be less sensitive to fomesafen than green algae).  Also, measurement endpoints reported by authors evaluate overall primary productivity of the sy瑳浥慲桴牥琠慨潣浭湵瑩⁹瑳畲瑣牵ⱥ眠楨档洠 祡戠潭敲爠獥潰獮癩⹥

 extended exposure.  At concentrations of ≤270 g/L for durations ≤504 hours (21 days) there was no observable abnormal behavior, mortality, or reduction of hemocyte cell viability in the snails (Russo et al 2007, Russo and Madec 2007).  Based on this work, it appears that fomesafen induces an immune response in freshwater snails at concentrations that may occur in the environment, but how these responses translate to measurable effects at an organism level (e.g., reduced growth, tumor activation, increase susceptibility to disease) are unknown.

4.4	Terrestrial Hazard Summary

Guideline studies evaluating effects on birds, mammals, and terrestrial invertebrates were available for fomesafen.  Several ECOTOX studies suitable for risk assessment purposes were available.  On an acute basis, fomesafen is slightly toxic to mammals and practically non-toxic to birds and honeybees.  Open literature studies indicate fomesafen may induce homolysis and formation of hepatic carcinomas in some strains of mice, but these occur at concentrations and durations of exposure far higher than likely to occur in the environment based on current registrations.  HED (USEPA 2006) has determined fomesafen is neither mutagenic nor carcinogenic for humans, nor does it appear to be associated with endocrine-disrupting effects.

Table   SEQ Table \* ARABIC  19   Terrestrial Toxicity Profile for Fomesafen

Assessment Endpoint	Surrogate Species	Toxicity Value Used 	Source Citation	Comments

Vertebrates

Acute Risk to Mammals	Guinea pig	LC50=607 mg/kg

95%CI=ND

Slope=ND	MRID 164901	Slightly toxic

Chronic Risk to Mammals	Rat	NOAEC=1,000 mg/kg

LOAEC=ND	MRID 144862	No reproductive effects

Acute Risk to Birds, Terrestrial-phase Amphibians, and Reptiles	Mallard duck

(oral dose)	LC50=>5,000 mg/kg

95%CI=ND

Slope=ND	MRID 163168	Practically non-toxic

	Mallard duck (dietary)	LC50=>20,000 mg/kg

NOAEC=20,000 mg/kg	MRID

163384	Practically non-toxic

Chronic Risk to Birds, Terrestrial phase Amphibians, and Reptiles Mallard duck	NOAEC=46 mg/kg

g/bee	MRID 135651	Practically non-toxic

Plants

Acute Risk to Monocots	Onion

(seedling emergence)	EC25= 0.084 lb ai/A

NOAEC=0.030 lb ai/A	MRID 46673801	Formulation

(Reflex 2 LC)

Acute Risk to Dicots	Lettuce

(vegetative vigor)	EC25= 0.002 lb ai/A

NOAEC=<0.002 lb ai/A	MRID 46673802

	4.5	Summary of Terrestrial Ecotoxicity Studies

4.5.1	Avian and Small Mammal Guideline Data

Guideline acute toxicity studies were available for birds (both dose and dietary), and small laboratory mammals (dose).  The oral LD50 for mallard ducks was greater than the highest dose tested (LD50>5,000 mg/kg, MRID163168).  Sub-acute dietary LC50s for both mallards and bobwhite quail were also greater than the highest dose tested (>20,000 mg/kg, MRIDs 163384, 164901)  Acute oral dose LD50s were available for guinea pigs (F 607 mg/kg, MRID 164901), mice (F 745 mg/kg, M 766 mg/kg, MRID164901) and rats (F 1499 mg/kg, M 1858 mg/kg, MRID 164901).  On the basis of both dose and dietary values, fomesafen is practically non-toxic to birds and slightly toxic to mammals.  Endpoints for female guinea pigs and mallard ducks were the most sensitive and were used to develop risk quotients.

Chronic guideline studies were available for birds (mallard duck, MRID 135639) and small laboratory mammals (rat, MRID 144862).  The bird guideline study did not establish a LOAEC, only determining that there were no effects at the highest (mean-measured) concentration tested for birds.  No sub-lethal effects were noted.  Lack of a LOAEC contributes significant uncertainty to the evaluation of chronic risk to birds.  The mallard duck NOAEC (46 ppm) is used in the determination of chronic risk to birds, but it may over-estimate the risk to birds.  In some cases, calculated exposure is near or above the maximum tested concentration.  In the rat study, no treatment related reproductive parameters were affected at the highest dose tested, resulting in a reproductive NOAEC of 1,000 mg/kg (MRID 144862).  Changes in the liver histopathology of both the parents and the offspring were noted at 1,000 mg/kg.  Histology changes are difficult to link with the assessment endpoints of growth, survival and fecundity evaluated by the Agency.  The reproductive NOAEC of 1,000 mg/kg was used to develop endpoints for mammals.

Because of fomesafen’s low toxicity to terrestrial organisms based on the available data, additional studies were not requested at the time of problem formulation, and this risk assessment was conducted using existing data.

4.5.2	Terrestrial Plant Data

<IP_ADDRESS>	Guideline Studies

Terrestrial plant guideline studies were available.  Fomesafen is effective, both pre- and post-emergent, against a variety of plants, although dicots appear to be more sensitive than monocots for both endpoints (seedling emergence and vegetative vigor).  The product is marketed as a control for broad-leafed weeds.

Guideline studies for seedling emergence (MRID 46673801, acceptable) and vegetative vigor (MRID 46673802, acceptable) were available at the time of this assessment.  Both studies evaluated the effects of fomesafen formulated product (REFLEX 2LC) on 10 plant species.  Species tested included 4 monocots (onion, barnyard grass, corn, and oats) and 6 dicots (radish, lettuce, tomato, soybean, oilseed rape, and sugarbeet).  Two concentrations were tested: 0.25 lb ai/A and 0.50 lb ai/A.  For monocots, the seedling emergence EC25s ranged from 0.084 lb ai/A to >0.48 lb ai/A (no effect at highest concentration tested).  Dicots were more sensitive, with the seedling emergence EC25s  ranging from 0.005-0.35 lb ai/A, with the exception of soybeans, with an EC25 of >0.48 lb ai/A (no effect at highest concentration tested).  Currently, soybeans are the crop for which fomesafen is most commonly used.  For dicots, the sensitivity range for the vegetative vigor endpoint is similar to the seedling emergence endpoint. EC25s for the dicot vegetative vigor endpoint range from 0.002-0.24 lb ai/A, with the exception of soybeans, with an EC25 of >0.47 lb ai/A (no effect at highest concentration tested).  For monocot vegetative vigor endpoint EC25s ranged from 0.29 lb ai/A to >0.47 lb ai/A (no effect at highest concentration tested). Based on this data, dicots appear more sensitive than monocots, and the vegetative vigor and seedling emergence endpoints appear to be equally sensitive.

<IP_ADDRESS>	Additional Registrant-Submitted Data

Efficacy data (MRID 135656) were part of the data package submitted for the original registration of fomesafen, and were considered in this assessment.  The efficacy data included pre-emergence and post-emergence treatment of 24 plant species, at two concentrations (0.25 and 1.0 kg ai/ha, or when converted, 0.42 and 0.54 lb ai/A).  The two concentrations are greater than most currently registered rates.  The plant species tested included both monocots (11 species) and dicots (13 species).  Both crop (7 species) and non-crop (17 species) plants were evaluated.  With the exception of soybeans, all plants tested experienced >20% “damage” when treated pre-emergence, with a significant number (65%) experiencing >80% damage when treated with the lower concentration (0.25 kg ai/ha).  Applied post-emergence, fomesafen is slightly less effective, with “damage” typically in the 0-40% range for monocots and 40-80% range for dicots.  The report did not specify how damage was quantified.

Additional plant data was submitted by the registrant during the registration review process (MRID 47587101).  This submission was not reviewed by EPA for acceptability, and raw data were not included, thus values reported herein do not represent anything statistically generated by the Agency.  Inclusion of these data is intended to provide a broader view of potential effects on plants than is provided by guideline data alone.  These data do not represent a regulatory endpoint.

The submission included an estimation a 10th percentile EC25, based on EC25s for a range of plant species tested by the registrant. The registrant’s database included 210 efficacy tests addressing 35 common crop and weed, with multiple application rates ranging from 0.01-0.45 lb ai/A.  Effects on the plants are rated on a visual scale of 1 to 10 compared to control plants, then converted to a percent effects scale (0%=no damage, 100%=complete efficacy).

4.5.3	Terrestrial Insect Data

Guideline tests for honeybees were submitted (MRID 135651, Core), as was a field chronic effects study on earthworms (MRID 135652).  The acute oral LD50 for honeybees was >50 g ai/bee, and the acute contact LD50 was >100 g ai/bee.  The field test for earthworms included two applications of fomesafen, applied at one-year intervals.  Fields were treated with 0.5 kg ai/ha and 5.0 kg ai/ha.  No adverse effects on total numbers, total weights, or numbers of individual species were noted at the 0.5 kg ai/ha treatment level.  A significant change in numbers of one species of earthworm (Allolobophura nocturna) was noted at the higher treatment level, but authors attributed this to modifications in grass cover caused by the herbicide treatment rather than direct toxic effects.

Studies were also submitted (MRID 135656) for eight species of invertebrates, from the orders Acarina, Hemiptera, Diptera, Lepidoptera, Coleoptera, and Nemotoda.  Fomsafen was applied to multiple life stages at concentrations of 250 and 500 ppm.  The greatest level of mortality in these tests was 9%.  Aphids (Aphis fabae) experienced mortality rates of 9% at concentrations of 250 ppm and 500 ppm.

4.5.4	ECOTOX Data

Some information regarding toxicity of fomesafen was available in the open litereature.  Full reviews of studies with endpoints potentially useful for this risk assessment are located in Appendix B.  No studies contained endpoints lower than those derived from guideline studies.  Summaries of studies evaluating biochemical and community-level endpoints are presented below.

<IP_ADDRESS>	Biochemical Endpoints

Several studies (Krijt et al 1993 (E95026); Krijt et al 1994a (E95399); Krijt et al 1994b (E95589); Krijt et al 1999 (E95400); Krijt et al 2003 (E95588)) evaluating the effects of fomesafen on mammalian hematocytes were located and reviewed.  The work of Krijt et al demonstrates that fomesafen ingested by mice at concentrations ranging from 100-2,500 ppm diet for 10 days causes elevated liver and fecal porphyrins, primarily via inhibition of the 7th enzyme of the heme biosynthesis protoprophyrin III oxidase (Krijt et al 1993).  Body weight gain is statistically significantly affected when fomesafen is administered at concentrations of 2,500 ppm in diet for 10 days (Krijt et al 1993).  The treatment groups in all investigations are small (n=3 or 4).  Mice used in the experiments were generally in the size range of 30-35 grams.  In some cases, fomesfen may also inhibit uroporphyrinogen III decarboxylase, but specific biochemical responses may vary dependent on the strain of mouse (Krijt et al 1994m, Krijt et al 2003).  Consumption of high doses (2,300-3,000 ppm) for extended periods of time (50 weeks to 14 months) caused development of precancerous cells in the liver (Krijt et al 1999).  Even with extended exposure, mice appeared to recover following a period of clean diet (3months) with liver porphyrins decreasing, and liver histology not noticeably different from controls (Krijt et al 1999).  In both studies that included a recovery period, liver porphyrin concentrations decreased rapidly following withdrawal from fomesafen, but did not return to the same levels as controls during the observation period (Krijt et al 1999).

g/L(“maximum mean”) in the fomesafen only ponds and as 19.4 ±7.6 g/L (“maximum mean”) in the fomesafen-Agral 90 ponds

on from concentrations of fomesafen ≤0.06 mg/L are not anticipated.  This should be caveated with the fact that the mesocosm community was dominated by cyanobacteria (which appear to be less sensitive to fomesafen than green algae based on registrant-submitted studies: MRID 46673806, green alga EC50 92 g/L; MRIDs 46673807, blue-green alga EC50 710 g/L).  Also, measurement endpoints reported by authors evaluate overall primary productivity of the system, rather than community structure, which may be more responsive.

4.5.5	Carcinogenicity, Mutagenicity, and Endocrine Disruption

) as the mode of action for fomesafen-induced hepatocarcinogeneisis in mice.  The data did not support either mutagensis or cytotoxicity followed by regenerative proliferation as alternative modes of action.” (USEPA 2006).

EPA is required under the FFDCA, as amended by 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 effect produced by a naturally occurring estrogen, or other such endocrine effects as the Administrator may designate.”  Following the recommendations of its Endocrine Disruptor Screening and Testing Advisory Committee (EDSTAC), EPA determined that there were scientific bases for including, as part of the program, 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.  When the appropriate screening and/or testing protocols being considered under the Agency’s Endocrine Disrupter Screening Program (EDSP) have been developed and vetted, fomesafen may be subjected to additional screening and/or testing to better characterize effects related to endocrine disruption.

4.5.6	Toxic Effects of Multi-Active Ingredient Labeled Products

Mammalian toxicity data were available for several formulated products, including one containing only fomesafen and all those containing multiple active ingredients.  Based on female guinea pig data (used as the assessment endpoint LD50 = 607 mg/kg bw), rats are less sensitive to fomesafen (female LD50 = 1,499 mg/kg bw).  For the formulations, rat data was compared to minimize variability associated with interspecies variation.

Flexstar (reg#100-1101), which contains only fomesafen (22.1%) has an LD50 of 3863 mg/kg (female, 95% CI not reported, MRID44030101).  Prefix (reg #100-1268), which contains both fomesafen and s-metolachlor (10.1% and 46.5% respectively) has an LD50 of 5,000 mg/kg (combined, 95% CI 2,865-8,390, MRID46952103).  Metolachlor has an LD50 of 2780 mg/kg (combined, 95% CI 2,180-3,545, MRID00015523).  Formulations containing bentazon (BAS 530 04 (29%), reg#7969-82 and Faster (29.8%), reg#7969-83) have an LD50 of >1210 mg/kg and 1470 mg/kg (95% CI 1,000-2,160, MRIDs 40340502, 40031302).  Bentazon has an LD50 of 1480 mg/kg (MRIDs 92065, 64314).

Although guideline studies are not designed to elucidate such effects, there do not appear to be additive or synergistic acute toxicity effects between fomesafen and any of the currently co-formulated active ingredients based on available data.  Toxic effects to mammals from ingestion of the formulated products containing fomesafen alone or fomesafen in conjunction with s-metolachlor or bentazon are not anticipated to exceed toxic effects estimated based on the technical active ingredient (Appendix H).

4.6	Incident Database Review

EFED maintains EIIS, a database containing reported incidents of damage to non-target species caused by pesticide use.  There are a total of 65 reported incidents (Appendix F) for fomesafen, 64 of which are damage to agricultural crops.  Incidents reported cover a range of 13 years (1992-2005), but many of them (83%) were reported in 2001-2003.  Corn was the crop most frequently reported damaged, accounting for 86% of the total plant damage reports.  The most frequently reported routes of exposure for corn were direct treatment, drift, and carryover.  In many cases (36%) the legality was classified as registered use.  In other cases (55%), the legality of application is unknown.  The certainty that the incident was related to fomesafen use was generally classified as probable.  Other crops damaged included green peas, cotton, and soybeans under registered use conditions.  Only 5 cases of misuse or accidental misuse were reported.

There is one report of a fish kill (I007601-001).  In this incident, there was a report of approximately 200 fish (channel catfish, crappie, largemouth bass, and redear sunfish) dying following a legal application to a soybean site.  The certainty of the kill being related to fomesafen runoff is classified as possible.  Application was in accordance with registered use.

5.0	Risk Estimation

Risk is estimated by calculating the ratio of the expected environmental concentration and the appropriate toxicity endpoint.  This value is the risk quotient (RQ), which is then compared to pre-established levels of concern (LOC) for each category evaluated.  The RQ methodology, LOCs, and specific details of calculation are contained in Appendix G.  The highest EECs and most sensitive endpoints are used to determine the screening level RQ.  Using these two values, theoretically, results in a conservative estimate of risk.

5.1	Aquatic RQ Summary

≤0.02.  Acute risk RQs for fresh-and saltwater plants, both vascular and non-vascular, ranged from <0.01 to 0.16.  In no cases did RQs for plants exceed the acute risk LOC.  Listed species RQs for fresh- and saltwater aquatic plants ranged from <0.01 to 1.6.  At the 0.5 lb ai/A application rate, RQs for freshwater non-vascular plants exceed the listed species LOC.  For some, but not all of the scenarios modeled, RQs for freshwater non-vascular plants exceed the listed species LOC at the application rate of 0.375 lb ai/A (RQs for all scenarios modeled are included in Appendix A).  In no cases did the modeled concentrations of fomesafen exceed the LOAEC for freshwater non-vascular plants.

Fomesafen appears to pose very low risk to aquatic ecosystems based on the data currently available.

Table 21  Summary of Aquatic RQs

Taxa	Acute RQ	Chronic RQ1	Endangered Species RQ2

Highest Section 24 Use on Cotton at 0.5 lb ai/A (MS scenario, ground application)

FW Aquatic Plants (algal)	0.16	NA1	1.6 a

FW Aquatic Plants (vascular)	0.07	NA1	0.24

FW Aquatic Invertebrates	<0.01	<0.01	<0.01

FW Fish	<0.01	NC	<0.01

SW Aquatic Plants	0.01	NA1	0.02

SW Aquatic Invertebrates	<0.01	<0.01	<0.01

SW Fish	<0.01	<0.01	<0.01

Highest Section 3 EEC: Use on Cotton at 0.375 lb ai/A (TX scenario, aerial application)

FW Aquatic Plants (algal)	0.13	NA1	1.2a

FW Aquatic Plants (vascular)	0.06	NA1	0.19

FW Aquatic Invertebrates	<0.01	<0.01	<0.01

FW Fish	<0.01	<0.01	<0.01

SW Aquatic Plants	<0.01	NA1	0.01

SW Aquatic Invertebrates	<0.01	0.02	<0.01

SW Fish	<0.01	<0.01	<0.01

Lowest EEC:  Use on Beans at 0.17 lb ai/A (MI scenario, aerial application)

FW Aquatic Plants (algal)	0.03	NA1	0.24

FW Aquatic Plants (vascular)	0.01	NA1	0.04

FW Aquatic Invertebrates	<0.01	<0.01	<0.01

FW Fish	<0.01	<0.01	<0.01

SW Aquatic Plants	<0.01	NA1	<0.01

SW Aquatic Invertebrates	<0.01	<0.01	<0.01

SW Fish	<0.01	<0.01	<0.01

1 There are no chronic aquatic plants tests. 2 Endangered species RQ for plants are calculated based on NOAEC.  Endangered species RQs for animals are calculated in the same way as acute risk values, but compared to a different LOC.  NA – not applicable, NC – Not calculated, data not available.  aExceeds endangered species LOC.

5.2	Terrestrial RQ Summary

5.2.1	Terrestrial Plants

Risk quotients were calculated based on the exposures estimated by both TerrPlant and AgDrift.  Calculations were made using data from both types of guideline studies (vegetative vigor and seedling emergence).  Evaluations were done for both monocots and dicots.  The most sensitive endpoint was dicot vegetative vigor (EC25=0.0016 lb ai/A, NOAEC=0.00098 lb ai/A).  For the seedling emergence tests, calculated EC05 was unavailable, and the reported NOAEC was greater than the calculated EC25, so the EC25 was used as the toxicity endpoint for the endangered species analysis.

<IP_ADDRESS>	TerrPlant

Because fomesafen is highly toxic to terrestrial plants, RQs for all application rates, both aerial and ground, are presented below.  It is especially toxic to dicots, and RQs exceed the LOC for both non-listed and listed species of plants in upland and wetland areas, as well as on the basis of spray drift alone.  RQs for non-listed dicots range from 4.3 (drift only, 0.17 lb ai/A) to 59.8 (wetland, 0.5 lb ai/A).  RQs for listed dicots range from >0.85 (drift only, 0.17 lb ai/A) to 59.8 (wetland, 0.5 lb ai/A).  For non-listed monocots, RQs exceed the LOC only in the wetland area.  Non-listed monocot RQs range from <0.1 (drift only, 0.17 lb ai/A) to 3.3 (wetland, 0.5 lb ai/A).  RQs for listed monocots range from <0.1 (drift only, 0.17 lb ai/A) to 3.3 (wetland, 0.5 lb ai/A).

Table 22  Terrestrial Plant Risk Quotients Based on TerrPlant

Application Rate

(lb ai/A)	Total Loading RQ

(Seedling Emergence)	Total Loading RQ

(Seedling Emergence)	Drift Only

(Vegetative Vigor)

	Upland Areas	Wetland Areas	Drift Only

	Monocot	Dicot	Monocot	Dicot	Monocot	Dicot

Aerial Applications   Non-listed Plants

0.5

Region 1 pine	0.60	10.87a	3.27a	59.78a	0.30	12.50a

0.375

Region 1 & 2	0.45	8.15a	2.66a	44.84a	0.22	9.38a

0.312

Region 3	0.37	6.78a	2.04a	37.30a	0.19	7.80a

0.25

Region 4	0.30	5.43a	1.64a	29.89a	0.15	6.25a

0.17

Region 5	0.20	3.70a	1.11a	20.33a	0.10	4.25a

Ground Applications   Non-listed Plants

0.5

Region 1 pine	0.36	6.52a	3.04a	55.43a	<0.1	2.50a

0.375

Region 1 & 2	0.27	4.89a	2.28a	41.58a	<0.1	1.88a

0.312

Region 3	0.22	4.07a	1.87a	34.59a	<0.1	1.56a

0.25

Region 4	0.18	3.26a	1.52a	27.72a	<0.1	1.25a

0.17

Region 5	0.12	2.22a	1.03a	18.85a	<0.1	0.85

Aerial Applications   Listed Plants

0.5

Region 1 pine	1.67a	10.87a	9.17a	59.78a	0.83	>12.50a

0.375

Region 1 & 2	1.25a	9.87a	6.88a	54.28a	0.63	>9.38a

0.312

Region 3	1.04a	8.21a	5.72a	45.16a	0.52	>7.80a

0.25

Region 4	0.83	6.58a	4.58a	36.18a	0.42	>6.25a

0.17

Region 5	0.57	4.47a	3.12 	24.61a	0.28	>4.25a

Ground Applications   Listed Plants

0.5

Region 1 pine	1.00a	7.89a	8.50a	67.11a	0.17	>2.50a

0.375

Region 1 & 2	0.75	5.92a	6.38a	50.33a	0.13	>1.88a

0.312

Region 3	0.62	4.93a	5.30a	41.87a	0.10	>1.56a

0.25

Region 4	0.50	3.95a	4.25a	33.55a	<0.1	>1.25a

0.17

Region 5	0.34	2.68a	2.89a	22.82a	<0.1	>0.85

a Exceeds or equals LOC of 1

<IP_ADDRESS>	AgDrift

Acute risk RQs and listed species RQs were calculated for aerial and ground applications (low boom and high boom) using the EC25 and NOAEC for the most sensitive dicot (lettuce EC25 0.0002 lb ai/A, NOAEC <0.00019 lb ai/A).  As the endpoints are so similar, RQs presented below apply to both listed and non-listed species.  Because the droplet size is an important parameter in determining spray drift, clearance distances and RQs were calculated for all droplet spectrum available in AgDrift.  The maximum extent of AgDrift Tier I modeling is approximately 1,000 ft from point of application for aerial applications, but the specific distance varies slightly dependent on the droplet spectrum.  For the sake of consistency, modeling was terminated at 950 ft for all spectra.  At this distance, the mathematical curve which describes the deposition is asymptotic, there are only small declines for greater linear distances.

 For aerial applications, fomesafen applied with a very fine to fine or fine to medium droplet spectrum exceeds the terrestrial plant LOC at all application rates.  For coarser droplet spectra, RQs range from 0.96 to 1.4, and clearance distances range from 250 ft to >950 ft.  Ground applications require a narrower buffer to clear the LOC, especially a low boom.  Clearance distances for ground applications range from 30 ft to 450 ft.

Table   SEQ Table \* ARABIC  20   Drift Deposition from Aerial Applications

Application Rate

(lb ai/A)	Very Fine to Fine	Fine to Medium	Medium to Coarse	Coarse to Very Coarse

	Clearance Distance

(ft)	RQ

unitless	Clearance Distance

(ft)	RQ

unitless	Clearance Distance

(ft)	RQ

unitless	Clearance Distance

(ft)	RQ

unitless

0.5	>950	10.7	>950	3.0	>950	1.4	700	0.98

0.375	>950	8.0	>950	2.3	>950	1.1	550	0.94

0.312	>950	6.7	>950	1.9	>950	1.1	550	0.94

0.25	>950	5.4	>950	1.5	600	0.96	350	0.98

0.17	>950	3.6	>950	1.0	400	0.94	250	0.96

Bold designates an exceedence (LOC=1)

Table   SEQ Table \* ARABIC  21   Drift Deposition from Ground Applications

Application Rate

(lb ai/A)	Low Boom	High Boom

	Very Fine to Fine	Fine to Medium	Medium to Coarse	Coarse to Very Coarse

	Clearance Distance

(ft)	RQ

unitless	Clearance Distance

(ft)	RQ

unitless	Clearance Distance

(ft)	RQ

unitless	Clearance Distance

(ft)	RQ

unitless

0.5	300	0.88	150	0.83	450	0.98	250	0.83

0.375	200	0.96	80	0.98	400	0.95	150	0.96

0.312	200	0.80	70	0.90	350	0.97	150	0.85

0.25	150	0.83	50	0.93	300	0.94	90	0.95

0.17	80	0.98	30	0.93	250	0.79	60	0.88

5.2.2	Avian RQ Summary

For birds, no acute LOCs were exceeded at any application rates.

Chronic RQs are reported as <RQ, due to the fact that the NOAEC established in the guideline study was not definitive.  At the application rate of 0.5 lb ai/A, chronic LOCs for birds in three out of the four food categories (short grass, tall grass, and broadleaf plants/small insects) were exceeded.  At the application rate of 0.375 lb ai/A, chronic LOCs for birds consuming the food categories of short grass and broadleaf plants/small insects were exceeded.  At the application rate of 0.17 lb ai/A, chronic LOCs for birds in the short grass food category were exceeded.

Table   SEQ Table \* ARABIC  22   Avian RQ Summary

Risk quotients based on Kenaga upper bound EECs	Acute dose-based RQs1 Acute dietary-based RQs1	Chronic RQs

	20g	100g	1000g	All birds	All birds

Maximum Application Rate 0.5 lb ai/A (pine seedlings, states in region 1)

Short grass	0.05	0.02	0.01	0.01	<2.61c

Tall grass	0.02	0.01	<0.01	<0.01	<1.20c

Broadleaf plants/small insects	0.03	0.01	<0.01	<0.01	<1.47c

Fruits/pods/seeds/lg insects	<0.01	<0.01	<0.01	<0.01	<0.16

Common Application Rate 0.375 lb ai/A (all crops, regions 1, 2)

Short grass	0.04	0.02	0.01	<0.01	<1.96c

Tall grass	0.02	0.01	<0.01	<0.01	<0.90

Broadleaf plants/small insects	0.02	0.01	<0.01	<0.01	<1.10c

Fruits/pods/seeds/lg insects	<0.01	<0.01	<0.01	<0.01	<0.12

Minimum Application Rate 0.17 lb ai/A (all crops, region 5)

Short grass	0.02	0.01	<0.01	<0.01	<0.89c

Tall grass	0.01	<0.01	<0.01	<0.01	<0.41

Broadleaf plants/small insects	0.01	<0.01	<0.01	<0.01	<0.50

Fruits/pods/seeds/lg insects	<0.01	<0.01	<0.01	<0.01	<0.06

a exceeds acute risk LOC (0.5)

b exceeds endangered species acute risk LOC (0.1)

c exceeds chronic risk LOC (1.0)

5.2.3	Small Mammal RQ Summary

For mammals, no acute LOCs were exceeded at any application rates.  The chronic LOC was exceeded only for small (15g) mammals eating short grass at the highest rate (0.5 lb ai/A, pine seedlings in AR, GA, MS, NC, and SC).

Table   SEQ Table \* ARABIC  23   Small Mammal RQ Summary

Risk Quotients based

on Kenaga

upper bound EEC	Acute

dose-based RQs	Chronic

dose-based RQs	Chronic dietary-based RQs

	15 g	35 g	1000 g	15 g	35 g	1000 g 	All mammals

Maximum Application Rate 0.5 lb ai/A (pine seedlings, states in region 1)

Short grass	0.09	0.07	0.04	1.04 c	0.89	0.48	0.48

Tall grass	0.04	0.03	0.02	0.48	0.41	0.22	0.22

Broadleaf plants/

small insects	0.05	0.04	0.02	0.59	0.50	0.27	0.27

Fruits/pods/seeds/

lg insects	0.01	<0.01	<0.01	0.07	0.06	0.03	0.03

Seeds (granivores)	<0.01	<0.01	<0.01	0.01	0.01	0.01	NA

Common Application Rate 0.375 lb ai/A (all crops, regions 1&2)

Short grass	0.06	0.05	0.03	0.78	0.67	0.36	0.36

Tall grass	0.03 	0.03	0.01	0.36	0.31	0.16	0.17

Broadleaf plants/

small insects	0.04	0.03	0.02	0.44	0.38	0.20	0.20

Fruits/pods/seeds/

lg insects	<0.01	<0.01	<0.01	0.05	0.04	0.02	0.20

Seeds (granivores)	<0.01	<0.01	<0.01	0.01	0.01	<0.01	NA

Minimum Application Rate 0.17 lb ai/A (all crops, region 5)

Short grass	0.03	0.02	0.01	0.35	0.30	0.16	0.16

Tall grass	0.01	0.01	0.01	0.16	0.14	0.07	0.07

Broadleaf plants/

small insects	0.02	0.01	0.01	0.20	0.17	0.09	0.09

Fruits/pods/seeds/

lg insects	<0.01	<0.01	<0.01	0.02	0.02	0.01	0.01

Seeds (granivores)	<0.01	<0.01	<0.01	<0.01	<0.01	<0.01	NA

a Equals or exceeds acute risk LOC (0.5)

b Equals or exceeds listed species acute risk LOC (0.1)

c Equals or exceeds chronic risk LOC (1.0)

5.2.4	Terrestrial Invertebrate Summary

g ai/bee (based on large insect estimator, 0.5 lb ai/A) to 8.64 g ai/bee (based on small insect estimator).  Using the acute contact LD50 of >100 g ai/bee, anticipated exposure at the treatment site would not be greater than approximately 9% of the LD50.  RQs calculated on this basis are shown below.  At the time of this assessment, OPP has an interim listed species acute risk LOC for terrestrial insects, but does not have a corresponding LOC for non-listed species.

g ai/bee)

0.50

(Pine seedlings, Region 1)	Small insects	<0.09 a	8.64

	Large insects	<0.01	0.96

0.375

(Regions 1, 2)	Small insects	<0.07 a	6.48

	Large insects	<0.01	0.72

0.017

(Region 5)	Small insects	<0.03	2.94

	Large insects	<0.01	0.32

a Equals or exceeds interim listed species acute risk LOC (0.05)

Non-guideline field tests on earthworms submitted by the registrant showed that fomesafen did not have observable adverse effects on total numbers, total weights, or numbers of individual species at a treatment level of 0.45 lb ai/A.  Decline in the population of one species of earthworms in the test plots was attributed to the change in plant cover on the plot as a result of the herbicide application.

6.0	Risk Description

Aquatic Risk

Based on currently available data, fomesafen appears to be of relatively low toxicity to aquatic animals in freshwater and estuarine/marine systems.  Both acute and chronic effects were considered.  Fomesafen is a light-dependent peroxidizing herbicide (LDPH), and may be more toxic under conditions of natural sunlight than in laboratory lighting (Matringe 1989).  The Agency has proposed testing this class of compounds under ultra-violet (UV) light conditions (EFED 2007), but as of the time of this risk assessment, such data were not available for fomesafen.  Based on fish early-life cycle tests submitted for oxyfluorfen, another chemical in this class, UV light conditions appear to increase the toxicity by approximately an order of magnitude (MRID 46585104).  To evaluate the effect of this increase in toxicity, fish early life cycle endpoints were adjusted by an order of magnitude and RQs were recalculated for all scenarios modeled.  In all cases, RQs were <0.015.  It should be noted, however, that the freshwater fish early life cycle endpoint was based on an ACR calculated from the saltwater fish studies, thus considerable uncertainty surrounds this endpoint.  Based on the effects noted in the oxyfluorfen study (decreased hatching time and reduced larval survival) and the mode of action of LDPHs, it seems possible that oxyfluorfen may have affected the viability of the egg cell membrane surrounding the larva. Given this possibility, extrapolation of the enhanced toxicity to the fish life stages used in the acute toxicity tests was not judged to be appropriate.  No tests conducted under UV light conditions were available for aquatic invertebrates, thus the type or magnitude of phototoxic effects on these types of organisms is unknown.  Given that many zooplankters have translucent bodies, and are present in the surface layers of water bodies where UV rays might penetrate (Barron et al 2000, Diamond et al 2005), photoenhanced toxicity to these taxa is a possibility.

In aquatic ecosystems, aquatic plants are the taxa most sensitive to fomesafen.  Aquatic plants (both vascular and non-vascular) are the primary producers, and may serve as the primary energy base in some aquatic systems either via consumption by herbivores or energy input to the detrital food web.  Perturbations to the base of the food chain have the potential to modify community structure and/or productivity of the affected system.  There are no acute risk LOC exceedences for any application rates.  RQs exceed the listed species LOC for freshwater non-vascular plants for the application rate of 0.375 lb ai/A in some scenarios modeled, and for the application rate of 0.5 lb ai/A in all scenarios modeled.  However, EECs (2-25 g/L) do not exceed the LOAEC (23 g/L), which is based on a 9% inhibition in biomass (MRID46673804).  Mesocosm studies (Caquet et al 2005, Caquet 2006) show that fomesafen concentrations of 30-60 g/L can cause perturbations in the system, but these perturbations are primarily associated with shifts in species composition and abundance rather than primary productivity.  Mesocosm studies conducted by Pershbarger et al (1997) indicate short-term effects on phytoplankton abundance and composition from concentrations of fomesafen ≤60 g/L are not measurable, but it must be noted that their experimental system was dominated by blue-green alga (EC50 = 71,000 g/L, MRID 46673807), which are less sensitive to fomesafen than the green alga (EC50 = 92 g/L, MRID 46673804).  The mesocosm studies were both conducted outdoors under natural sunlight conditions, thus any photoenhancement of fomesafen toxicity for these taxa would be implicitly incorporated into study results.  Measurable differences in the algal composition and productivity of water bodies receiving runoff from fields treated with fomesafen at the application rates evaluated in this document are not anticipated.  At the time of this assessment, there were no listed freshwater non-vascular plants, and no indications of any obligate relationships between a listed species and freshwater algae.

Fomesafen may indirectly affect aquatic systems by damaging plants in adjacent wetland or riparian zones.  Modification of the vegetation in wetlands or riparian zones could cause decreased allochthonous input, increased sediment input, destabilization of the stream bank, or changes in the structural components (plant).  Effects on waterbody associated plant communities can be minimized by ensuring an adequate offset distance is maintained between the application site and the wetland or riparian zone.  Appropriate offset distances are discussed in the terrestrial plants section.

Table   SEQ Table \* ARABIC  25   Summary of Risk to Non-listed Aquatic Organisms

Assessment Endpoint	Crops	Estimator	LOC Exceedence

Freshwater

Acute Toxicity to Fish and Aquatic-phase Amphibians	Pine seedlings

Cotton, Beans (soy, snap, dry)

Cotton, Beans (soy, snap, dry)	MS cotton (0.5lb ai)

TX cotton (0.375 lb ai)

MI beans (0.375 lb ai)	No

No

No

Chronic Toxicity

Fish and Aquatic-phase Amphibians	Pine seedlings

Cotton, Beans (soy, snap, dry)

Cotton, Beans (soy, snap, dry)	MS cotton (0.5lb ai)

TX cotton (0.375 lb ai)

MI beans (0.375 lb ai)	No

No

No

Acute Toxicity to Aquatic Invertebrates	Pine seedlings

Cotton, Beans (soy, snap, dry)

Cotton, Beans (soy, snap, dry)	MS cotton (0.5lb ai)

TX cotton (0.375 lb ai)

MI beans (0.375 lb ai)	No

No

No

Chronic Toxicity

Aquatic Invertebrates	Pine seedlings

Cotton, Beans (soy, snap, dry)

Cotton, Beans (soy, snap, dry)	MS cotton (0.5lb ai)

TX cotton (0.375 lb ai)

MI beans (0.375 lb ai)	No

No

No

Acute Toxicity to Aquatic Plants

(non-vascular)	Pine seedlings

Cotton, Beans (soy, snap, dry)

Cotton, Beans (soy, snap, dry)	MS cotton (0.5lb ai

TX cotton (0.375 lb ai)

MI beans (0.375 lb ai)	No

No

No

Acute Toxicity to Aquatic Plants (vascular)	Pine seedlings

Cotton, Beans (soy, snap, dry)

Cotton, Beans (soy, snap, dry)	MS cotton (0.5lb ai

TX cotton (0.375 lb ai)

MI beans (0.375 lb ai)	No

No

No

Saltwater

Acute Toxicity to Fish	Pine seedlings

Cotton, Beans (soy, snap, dry)

Cotton, Beans (soy, snap, dry)	MS cotton (0.5lb ai)

TX cotton (0.375 lb ai)

MI beans (0.375 lb ai)	No

No

No

Chronic Toxicity to Fish 	Pine seedlings

Cotton, Beans (soy, snap, dry)

Cotton, Beans (soy, snap, dry)	MS cotton (0.5lb ai)

TX cotton (0.375 lb ai)

MI beans (0.375 lb ai)	No

No

No

Acute Toxicity to Aquatic Invertebrates	Pine seedlings

Cotton, Beans (soy, snap, dry)

Cotton, Beans (soy, snap, dry)	MS cotton (0.5lb ai)

TX cotton (0.375 lb ai)

MI beans (0.375 lb ai)	No

No

No

Chronic Toxicity

Aquatic Invertebrates	Pine seedlings

Cotton, Beans (soy, snap, dry)

Cotton, Beans (soy, snap, dry)	MS cotton (0.5lb ai)

TX cotton (0.375 lb ai)

MI beans (0.375 lb ai)	No

No

No

Acute Toxicity to Aquatic Plants 	Pine seedlings

Cotton, Beans (soy, snap, dry)

Cotton, Beans (soy, snap, dry)	MS cotton (0.5lb ai)

TX cotton (0.375 lb ai)

MI beans (0.375 lb ai)	No

No

No

Terrestrial Risk

In general, fomesafen presents low risk to terrestrial animals on an acute basis, with no acute LOC exceedences for either birds or mammals.  However, there are chronic LOC exceedences for both birds and mammals at all application rates.  Fomesafen poses a risk to terrestrial plants, especially dicots, in areas which may be subject to drift or runoff from the application site.  Due to the sensitivity of dicots to fomesafen, effect from drift may occur as far away from the use site as 1,000 ft for aerial applications and 300 ft for ground applications.

6.2.1	Birds, Reptiles, and Amphibians

In the avian reproduction study on mallard ducks (MRID 135639), no endpoints were affected, thus the NOAEC was established as the highest dose tested (46 mg/kg diet).  No LOAEC was determined, so based on the available data, the meaning of the chronic LOC exceedences for birds is difficult to interpret, either in terms of which endpoints might be affected, or if chronic exposure to fomesafen is at levels that would trigger these effects.

It should also be noted that generally bobwhite quail, which were not tested for fomesafen, are more sensitive than mallard ducks.  Avian data for fomesafen and several structurally similar compounds, acifluorfen (PCs<PHONE_NUMBER>04), oxyfluorfen (PC 111601), and lactofen (PC 128888), is presented below.  The data available for the other chemicals suggests reproductive effects of fomesafen may include reduction in embryo survival, number of hatchlings, and/or number of eggs laid.  The data also suggests that bobwhite quail are the more sensitive species for this class of chemicals, thus the mallard data used in the risk assessment may underestimate the risk to more sensitive species.  Mammalian data were also considered in an attempt to characterize the potential chronic toxicity for birds.  Reproductive effects were noted in the lactofen and oxyfluorfen tests.

Because the reported NOAECs and LOAECs are in part an artifact of the test concentrations selected and sufficient data points are not available to generate chronic dose-response curves, no specific conclusions should be drawn regarding relative toxicity of the compounds.  In the absence of more definitive chronic avian data for fomesafen, the Agency concludes that there is a chronic risk to insectivorous or herbivorous birds, reptiles, and/or terrestrial-phase amphibians foraging in or near the treated area for all application rates.  Potential effects on the fecundity of frugivorous birds foraging in or near the treated area should be anticipated for the 0.5 lb ai/A application rate.

Table   SEQ Table \* ARABIC  26   Comparison of Chronic Data for Acifluorfen, Fomesafen, and Oxyfluorfen.

Chemical	Test Organism	NOAEC

(mg/kg diet)	LOAEC

(mg/kg diet)	Endpoints Affected

Avian

Acifluorfen

(PC114401)	Bobwhite quail

(MRID 107491)	20	100	Reduced number of embryos

	Mallard duck

(MRID 107492)	100	>100	No endpoint affected

Fomesafen	Mallard duck

(MRID 135639)	46	>46	No endpoint affected

Lactofen

(PC128888)	No chronic data available

Oxyfluorfen

(PC111601)	Bobwhite quail

(MRID 46070102)	124	256	Survivor weight, embryo survival, number of hatchlings

	Mallard duck

(MRID 46070101)	506	751	Eggs laid, embryo survival, number of hatchlings

Mammalian

Acifluorfen

(PC114401)	Rat

(MRID155548)	2500	ND	No reproductive effects

Fomesafen	Rat

(MRID144862)	1000	ND	No reproductive effects

Lactofen

(PC128888)	Rat

(AC73859)	50	500	Reduced pup weight

Oxyfluorfen

(PC111601)	Rat

(MRID42014901)	400	1600	Decreased body weight, # live pups/litter

6.2.2	Mammals

For mammals, no acute LOCs were exceeded at any application rate.  The chronic LOC was exceeded only for small (15g) mammals eating short grass at the highest application rate (0.5 lb ai/A, pine seedlings in AR, GA, MS, NC, and SC).  Thus effects on the endpoints of growth, survival, and fecundity are not anticipated at the 0.375 lb ai/A application rate.

Open literature data demonstrated elevated levels of liver and fecal porphyrins in mice fed 100 mg/kg diet for 10 days (Krijt et al 1994b).  Based on TREX estimates of dietary EECs, only the 0.5 lb ai/A rate exceeds 100 mg/kg rate.  Given the existing body of data regarding fomesafen effects on the liver porphyrins of small mammals, effects on this biochemical endpoint appear unlikely, although there is a difference in sensitivity amongst strains of mice (Krijt et al 1994a).  Where laboratory mice strains are in a species sensitivity distribution as compared to small wild mammals is unknown.

6.2.3	Terrestrial Invertebrates

Based on available data, effects on terrestrial invertebrates, while possible, do not appear likely.  Lack of indicated toxicity in guideline bee studies, guideline aquatic invertebrate studies, and non-guideline studies on soil invertebrates, arthropods, and in aquatic mesocoms support this conclusion.

Table   SEQ Table \* ARABIC  27   Summary of Risk to Non-Listed Terrestrial Animals

Assessment Endpoint	Application Rate

lb ai/A	Size Class

(g)	LOC Exceedence1	Clearance estimate

Distance from site (ft)	Rate

(lb ai/A)

Vertebrates

Acute Risk to Mammals	0.5	15

35

1000	No

No

No	Clears at current rate

	0.375	15

35

1000	No

No

No	Clears at current rate

	0.17	15

35

1000	No

No

No	Clears at current rate

Chronic Risk to Mammals	0.5	15

35

1000	Yes (SG)

No

No	Aerial 02

Ground 10	0.473

Clear

Clear

	0.375	15

35

1000	No

No

No	Clears at current rate

	0.17	15

35

1000	No

No

No	Clears at current rate

Acute Risk to Birds, Terrestrial-phase Amphibians, and Reptiles	0.5	20

100

1000	No

No

No	Clears at current rate

	0.375	20

100

1000	No

No

No	Clears at current rate

	0.17	20

100

1000	No

No

No	Clears at current rate

Chronic Risk to Birds, Terrestrial-phase Amphibians, and Reptiles	0.5 All	Yes (SG, TG, BL, SL)	Aerial 100

Ground 10	0.192

	0.375	All	Yes (SG, BL)	Aerial 100

Ground 10	0.192

	0.17	All	Yes (SG)	Aerial 100

Ground 10	0.192

Invertebrates

Acute Risk to Invertebrates	All rates	All	Risk appears unlikely	Not applicable

1 LOC exceedences using more conservative dose-based estimates

2 AgDrift clearance estimate is ~45% deposition directly below aircraft

3 Clearance level is for short grass estimate

4 OPP does not currently have an acute risk LOC for non-listed terrestrial invertebrates

Feeding categories:  short grass (SG), tall grass (TG), broadleaf plants, small insects (BL), seeds, large insects (SL), granivore-mammals only (G)

NA – Not applicable

6.2.4	Plants

The non-target organisms of greatest concern for fomesafen are plants in the overspray, runoff, and spray drift zones.  Fate data do not indicate fomesafen is likely to be subject to long-range atmospheric transport, thus this route of exposure has not been addressed in the assessment.  It is, however, persistent in soil, and may affect plants growing in the soil of treated fields or overspray areas for an extended period (approximately a year) following application.  Because of the persistence, it is also likely to accumulate in fields repeatedly treated with fomesafen, even if the field is only treated in alternate years.  The theoretical maximum concentration occurs in about 10 years if the field is treated in alternate years.  Maximum residual concentration for an application rate of 0.375 lb ai/A is 0.29 lb ai/A, and for an application rate of 0.5 lb ai/A is 0.38 lb ai/A.  These concentrations are greater than the seedling emergence EC25s of the most sensitive dicot (tomato, EC25 0.005 lb ai/A) and the most sensitive monocot (onion, EC25 0.084 lb ai/A).

Shallow groundwater used for irrigation of agricultural fields could potentially contain sufficient fomesafen to affect some crops.  Based on estimated concentrations delivered to a field receiving 2 inches of irrigation water (0.0004-0.0077 lbs ai/A, based on application rate of 0.5 lb ai/A to field), sensitive crop species such as radish, lettuce, oilseed rape, and tomato (EC25s of 0.002-0.008 lb ai/A) could be affected.  How long fomesafen will persist in the groundwater is not well defined.

Fomesafen has the potential to adversely affect plant communities of concern beyond the edges of the treated field.  Plants potentially affected by fomesafen include crops in neighboring fields, hedgerows, riparian zones, and wetlands.  Using AgDrift (Tier 1), EFED was unable to calculate the distance required for the acute plant risk to fall below the LOC for aerial applications, with toxicity predicted to occur at least to 900 ft beyond the application point for aerial applications and 300 ft for ground applications.  Potential runoff effects to wetlands near the treatment site are difficult to evaluate, as the amount of runoff is greatly influenced by slope, presence of buffers, and degrees of channelization in runoff swales.  Wetlands receiving direct runoff from treated sites are likely to be affected.

Because fomesafen is an herbicide, it may affect the primary productivity, community composition, and/or structure of herbaceous communities located near the margins of the treated fields.  EFED has no data with which to evaluate the potential effect on woody plants, although given the mode of action for fomesafen (cell membrane disruption), woody plants may be more resistant.  Modifications to the plant community may have significant effects on the populations of animals dependent on those communities.

Table   SEQ Table \* ARABIC  28   Summary of Risk to Non-listed Terrestrial Plants

Assessment Endpoint	Type of Plant	Application Rate

lb ai/A	LOC Exceedence2	Clearance estimate1

Distance from site (ft)	Rate

(lb ai/A)

Acute Risk to Monocots	Aerial Application

	Upland	0.5	No	Clears at current rate

(Based on

runoff and drift)

0.375	No

	0.312	No

	0.25	No

	0.17	No

Wetland	0.5	Yes	100	0.084

0.375	Yes

0.312	Yes

0.25	Yes

0.17	Yes

	Ground Application

	Upland	0.5	No	Clears at current rate

(Based on

runoff and drift)

0.375	No

	0.312	No

	0.25	No

	0.17	No

Wetland	0.5	Yes	10	0.084

0.375	Yes

0.312	Yes

0.25	Yes

0.17	Yes

Acute Risk to Dicots	Aerial Application

	Upland	0.5	Yes	>900	0.002

0.375	Yes

0.312	Yes

0.25	Yes

0.17	Yes

	Wetland	0.5	Yes

0.375	Yes

0.312	Yes

0.25	Yes

0.17	Yes

	Ground Application

	Upland	0.5	Yes	300	0.002

0.375	Yes	200

	0.312	Yes	200

	0.25	Yes	150

	0.17	Yes	80

Wetland	0.5	Yes	300

	0.375	Yes	200

	0.312	Yes	200

	0.25	Yes	150

	0.17	Yes	80

	1  Based on drift estimates from AgDrift, does not include runoff

6.3	Endangered Species

6.3.1	Aquatic Listed Species

No aquatic endangered species are at risk for direct effects from fomesafen.  Although there are listed species LOC exceedences for freshwater non-vascular plants, there were no listed freshwater non-vascular plants at the time of this assessment.  Additionally, no listed species have been identified as having an obligate relationship with freshwater non-vascular plants.  This results in a determination of no effect for aquatic organisms on the basis of direct effects.  Indirect effects to aquatic organisms are possible, based on potential effects on riparian and wetland plant communities.  For an evaluation of indirect effects, please see the section on endangered plants.

Table   SEQ Table \* ARABIC  29   Summary of Risk to Listed Aquatic Organisms

Assessment Endpoint	Crops	Estimator	LOC Exceedence

Freshwater

Acute Toxicity to Fish and Aquatic-phase Amphibians	Pine seedlings

Cotton, Beans (soy, snap, dry)

Cotton, Beans (soy, snap, dry)	MS cotton (0.5lb ai)

TX cotton (0.375 lb ai)

MI beans (0.375 lb ai)	No

No

No

Chronic Toxicity

Fish and Aquatic-phase Amphibians	Pine seedlings

Cotton, Beans (soy, snap, dry)

Cotton, Beans (soy, snap, dry)	MS cotton (0.5lb ai)

TX cotton (0.375 lb ai)

MI beans (0.375 lb ai)	No

No

No

Acute Toxicity to Aquatic Invertebrates	Pine seedlings

Cotton, Beans (soy, snap, dry)

Cotton, Beans (soy, snap, dry)	MS cotton (0.5lb ai)

TX cotton (0.375 lb ai)

MI beans (0.375 lb ai)	No

No

No

Chronic Toxicity

Aquatic Invertebrates	Pine seedlings

Cotton, Beans (soy, snap, dry)

Cotton, Beans (soy, snap, dry)	MS cotton (0.5lb ai)

TX cotton (0.375 lb ai)

MI beans (0.375 lb ai)	No

No

No

Acute Toxicity to Aquatic Plants

(non-vascular)	Pine seedlings

Cotton, Beans (soy, snap, dry)

Cotton, Beans (soy, snap, dry)	MS cotton (0.5lb ai)

TX cotton (0.375 lb ai)

MI beans (0.375 lb ai)	Yes

Yes

No

Acute Toxicity to Aquatic Plants (vascular)	Pine seedlings

Cotton, Beans (soy, snap, dry)

Cotton, Beans (soy, snap, dry)	MS cotton (0.5lb ai)

TX cotton (0.375 lb ai)

MI beans (0.375 lb ai)	No

No

No

Saltwater

Acute Toxicity to Fish	Pine seedlings

Cotton, Beans (soy, snap, dry)

Cotton, Beans (soy, snap, dry)	MS cotton (0.5lb ai)

TX cotton (0.375 lb ai)

MI beans (0.375 lb ai)	No

No

No

Chronic Toxicity to Fish 	Pine seedlings

Cotton, Beans (soy, snap, dry)

Cotton, Beans (soy, snap, dry)	MS cotton (0.5lb ai)

TX cotton (0.375 lb ai)

MI beans (0.375 lb ai)	No

No

No

Acute Toxicity to Aquatic Invertebrates	Pine seedlings

Cotton, Beans (soy, snap, dry)

Cotton, Beans (soy, snap, dry)	MS cotton (0.5lb ai)

TX cotton (0.375 lb ai)

MI beans (0.375 lb ai)	No

No

No

Chronic Toxicity

Aquatic Invertebrates	Pine seedlings

Cotton, Beans (soy, snap, dry)

Cotton, Beans (soy, snap, dry)	MS cotton (0.5lb ai)

TX cotton (0.375 lb ai)

MI beans (0.375 lb ai)	No

No

No

Acute Toxicity to Aquatic Plants 	Pine seedlings

Cotton, Beans (soy, snap, dry)

Cotton, Beans (soy, snap, dry)	MS cotton (0.5lb ai)

TX cotton (0.375 lb ai)

MI beans (0.375 lb ai)	No

No

No

Terrestrial Listed Species

There are no listed species acute risk LOC exceedences for birds or mammals.  Chronic risk LOCs were exceeded for herbivorous birds at all application rates except the 0.17 lb ai/A rate (Region 5).  Chronic risk LOCs were exceeded for insectivorous birds at applications rates of 0.375 lb ai/A and higher (Region 1 & 2).  As birds are the surrogate for reptiles and terrestrial-phase amphibians, these exceedences also apply to those taxa.  Exceedences are based on a non-definitive endpoint from a guideline study, and thus may overestimate risk.  In absence of a definitive endpoint, the Agency assumes effects may occur at any exposure concentrations about the established NOAEC.  The AgDrift model was used to estimate the distances from the application site for exposure to drop below the level of concern based on the most conservative estimator (short grass).  The resulting clearance distances were 10 ft for ground applications and 100 ft for aerial applications.  Thus, for listed insectivorous and herbivorous birds, reptiles, or amphibians nesting or foraging within 100 ft of the application source, the direct effects determination is may affect, likely to adversely affect.  For organisms located greater than 100 ft away from the field, the direct effects determination is no effect.    REF _Ref217117673 \h  \* MERGEFORMAT  Table 31  and   REF _Ref217117726 \h  \* MERGEFORMAT  Table 32  show which species have been identified as potentially at risk, based on application rate, geographic location, and dietary habits.  Indirect effects on listed birds, reptiles, and terrestrial-phase amphibians are possible, based on potential effects on plant communities and/or designated habitat.  For an evaluation of indirect effects, please see the section on endangered plants.

For mammals, there were no listed species acute risk LOC exceedences or chronic risk LOC exceedences for any of the existing Section 3 application rates.  For application rates of 0.375 lb ai/A or less, the effects determination for mammals is no effect.  Chronic risk LOCs were exceeded for the small herbivorous mammals (15g) at the 0.5 lb ai/A application rate, which applies only to pine seedlings in AR, GA, MS ,NC, and SC.  Based on the available data (LOCATES and dietary information), no listed small herbivorous mammals occur in these locations.

Table   SEQ Table \* ARABIC  30   Summary of Risk to Listed Terrestrial Animals

Assessment Endpoint	Application Rate

lb ai/A	Size Class

(g)	LOC Exceedence1	Clearance estimate

Distance from site (ft)	Rate

(lb ai/A)

Vertebrates

Acute Risk to Mammals	0.5	15

35

1000	No

No

No	Clears at current rate

	0.375	15

35

1000	No

No

No	Clears at current rate

	0.17	15

35

1000	No

No

No	Clears at current rate

Chronic Risk to Mammals	0.5	15

35

1000	Yes (SG)

No

No	Aerial 02

Ground 10	0.473

Clear

Clear

	0.375	15

35

1000	No

No

No	Clears at current rate

	0.17	15

35

1000	No

No

No	Clears at current rate

Acute Risk to Birds, Terrestrial-phase Amphibians, and Reptiles	0.5	20

100

1000	No

No

No	Clears at current rate

	0.375	20

100

1000	No

No

No	Clears at current rate

	0.17	20

100

1000	No

No

No	Clears at current rate

Chronic Risk to Birds, Terrestrial-phase Amphibians, and Reptiles	0.5 All	Yes (SG, TG, BL, SL)	Aerial 100

Ground 10	0.192

	0.375	All	Yes (SG, BL)	Aerial 100

Ground 10	0.192

	0.17	All	No	Clears at current rate

Invertebrates

Acute Risk to Invertebrates	0.5	All	Yes	Aerial 0

Ground 10	0.28

	0.375	All	Yes

	0.17	All	No	Clears at current rate

1 LOC exceedences using more conservative dose-based estimates

2 AgDrift clearance estimate is ~45% deposition directly below aircraft

3 Clearance level is for short grass estimate

4 OPP does not currently have an acute risk LOC for non-listed terrestrial invertebrates

Feeding categories:  short grass (SG), tall grass (TG), broadleaf plants, small insects (BL), seeds, large insects (SL), granivore-mammals only (G)

Indirect Effects and Critical Habitat Effects (Birds, Reptiles, Amphibians, and Mammals)

The most likely indirect effect on listed animals is modification of habitat as a result of damage to plants.  The habitat modification could include reduced food supply, locations for nesting or burrowing, and/or reduced cover for predator avoidance.  Both monocots and dicots are affected by fomesafen, although based on available data, effects on sensitive species of dicots occur at lower concentrations.  The assessment endpoint used for non-listed plant species is the EC25, a measure of a 25% reduction in the most sensitive endpoint for the most sensitive plant.  Although plant sensitivity to fomesafen varies, determining the range of sensitivities in plant communities near application sites is beyond the scope of this assessment.  For fomesafen, the most sensitive endpoints are typically biomass and percent survival.  While it is difficult to predict community-level effects on the plant community supporting the listed plants, a 25% reduction in these endpoints is likely to reduce the viability of any affected population.  Degradation of habitat could indirectly affect listed species in a number of ways.  Thus, for purposes of this assessment, exceedence of the non-listed plant LOC is considered a “may affect, likely to adversely affect” for listed animals, and has the potential to modify designated critical habitat for habitat located within 1,000 ft of aerial applications and 850 ft of ground applications.

Potential mitigation measures include but are not limited to: 1)  restricting applications of fomesafen within 1,000 ft of populations of endangered plants, and 2)  restricting applications of fomesafen at sites where runoff to wetland areas is likely. Removal of aerial application methods from the label is another possibility.  However, in light of the fact that anticipated effects zones are almost as wide for ground applications, this may not be the most beneficial mitigation.

Table   SEQ Table \* ARABIC  31 .  Listed birds potentially at risk from fomesafen

Common Name	Scientific Name	Pine	Soybean	Cotton	Dry Beans	Snap Beans

Flycatcher, Southwestern Willow	Empidonax trailii extimus

R1	R1	R1

	Plover, Piping	Charadrius melodus	R1	R1, R2	R1, R2	R1, R2	R1, R2

Tern, California Least	Sterna antillarum browni

R1	R1	R1

	Tern, Interior Least	Sterna antillarum	R1	R1, R2	R1

R1, R2

Warbler, Bachman’s	Vermivora bachmanii	R1	R2

	R1, R2