![](media/image1.wmf){width="1.3576388888888888in"
height="1.375in"}UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

![](media/image1.wmf){width="1.3576388888888888in"
height="1.375in"}WASHINGTON D.C., 20460

**[Registration Review]{.smallcaps}**

**[Ecological Risk Assessment]{.smallcaps}**

**[Problem Formulation for:]{.smallcaps}**

**[FOMESAFEN]{.smallcaps}**

**[Prepared By:]{.smallcaps}**

**Paige Doelling Brown, Ph.D., Fisheries Biologist**

**James Hetrick, Ph.D., Senior Chemist**

**Environmental Risk Branch 1**

**Environmental Fate and Effects Division**

**Office of Pesticide Programs**

**[Approved By:]{.smallcaps}**

**Nancy Andrews, Ph.D., Branch Chief**

**Environmental Risk Branch 1**

**Environmental Fate and Effects Division**

**Office of Pesticide Programs**

**[Stressor Source and Distribution]{.smallcaps}**

The source of the stressor considered in this document is sodium salt of
fomesafen.

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. Fomesafen is a diphenylether. It disrupts the cell
membrane of the plant
([www.syngentacroprotection-us.com](http://www.syngentacroprotection-us.com/))
by penetrating into the cytoplasm and causing formation of peroxides and
free electrons ([www.abcbids.org](http://www.abcbids.org/)). The
specific mode of action is inhibition of protoporphyrinogen oxidase
([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.

Fomesafen is highly persistent in soil (63-527 days, 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.

**[Integration of Available Information]{.smallcaps}**

The risk assessments available in the docket, and which serves as the
basis for this problem formulation, include the following:

-   Ecological Risk Assessment in Support of Docket Preparation for
    Registration Review of Fomesafen (DP 306023), January 18, 2006

**[Ecological Effects]{.smallcaps}**

**[Available Toxicity Studies]{.smallcaps}**

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 most sensitive endpoint
for each taxa evaluated. In aquatic systems, taxa evaluated include
aquatic plants, invertebrates, and fish. Fish serve as a surrogate for
aquatic-phase amphibians. 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 is used as a surrogate for reptiles and
terrestrial-phase amphibians. Mammal data is derived from guideline
studies conducted on laboratory rats, mice, or rabbits.

**[Aquatic Guideline Data]{.underline}**

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. Details of conversion are
included in Appendix E. Aquatic plant data were submitted by the
registrant (upon request by EFED), during the development of this risk
assessment. Although the Data Evaluation Review (DER) process has not
yet been completed for these studies, they have been provisionally
classifed as Supplemental, and the toxicity data has been incorporated
into the assessment. Overall, fomesafen is slightly toxic to practically
nontoxic to invertebrates and practically non-toxic to fish on an acute
basis (Table 1). Chronic data were also available, and are presented in
Table 2.

+---------------+----------+-------------+-----------+---------------+
| Table 1 Acute |          |             |           |               |
| Aquatic Data  |          |             |           |               |
| from          |          |             |           |               |
| Registr       |          |             |           |               |
| ant-submitted |          |             |           |               |
| Studies       |          |             |           |               |
+---------------+----------+-------------+-----------+---------------+
| # Species     | ## LC~5  | ## 95%      | **NOAEC   | **Cla         |
|               | 0~ (ppm) |  C.I. (ppm) | (ppm)**   | ssification** |
|               |          |             |           |               |
|               |          |             |           | **(MRID)**    |
+---------------+----------+-------------+-----------+---------------+
| ### Freshwa   |          |             |           |               |
| ter Organisms |          |             |           |               |
+---------------+----------+-------------+-----------+---------------+
| Green alga^1^ | 0.12     | 0.05-0.34   | 0.02      | Supplemental  |
| *(Selenastrum |          |             |           |               |
| ca            | (        |             |           | \(46673804\)  |
| pricornutum)* | biomass) |             |           |               |
|               |          |             |           | Technical     |
+---------------+----------+-------------+-----------+---------------+
| Water flea    | 376      | 323-437     | 117       | Core^2,\ 3^   |
|               |          |             |           |               |
| *(Daphnia     | (pra     |             |           | \(163169\)    |
| magna)*       | ctically |             |           |               |
|               | n        |             |           | Formulation   |
|               | ontoxic) |             |           |               |
+---------------+----------+-------------+-----------+---------------+
| Rainbow Trout | 126      | 117-135     | 80        | Core^2,\ 3^   |
|               |          |             |           |               |
| *             | (pra     |             |           | \(103023\)    |
| (Onchorynchus | ctically |             |           |               |
| mykiss)*      | n        |             |           | Formulation   |
|               | ontoxic) |             |           |               |
+---------------+----------+-------------+-----------+---------------+
| ### E         |          |             |           |               |
| stuarine/ Mar |          |             |           |               |
| ine organisms |          |             |           |               |
+---------------+----------+-------------+-----------+---------------+
| Marine        | 1.51     | ND          | 0.94      | Supplemental  |
| diatom^1^     |          |             |           |               |
| *(Skeletonema | (        |             |           | \(46673806\)  |
| costatum)*    | biomass) |             |           |               |
|               |          |             |           | Technical     |
+---------------+----------+-------------+-----------+---------------+
| Mysid shrimp  | 25       | 19-38       | ND        | Core^2^       |
|               |          |             |           |               |
| *(Mysidopsis  | (        |             |           | \(135647\)    |
| bahia)*       | slightly |             |           |               |
|               | toxic)   |             |           | Technical     |
+---------------+----------+-------------+-----------+---------------+
| Sheepshead    | \>163    | ND          | \>163     | Core^2,\ 3^   |
| minnow        |          |             |           |               |
|               | (pra     |             |           | \(135651\)    |
| *(Cyprinodon  | ctically |             |           |               |
| varigetus)*   | n        |             |           | Formulation   |
|               | ontoxic) |             |           |               |
+---------------+----------+-------------+-----------+---------------+

^1^Provisional data and classification, pending final review. ^2^Data
are from studies originally reviewed and classified in 1984, some of
which used formulated product. ^3^For purposes of this risk assessment,
test concentrations were adjusted for percent a.i. if necessary, and
endpoints were re-calculated using TOXANAL software. ND-not determined.

+-----------------+------+------+--------------------+---------------+
| Table 2 Chronic |      |      |                    |               |
| Aquatic Data    |      |      |                    |               |
| from            |      |      |                    |               |
| Regis           |      |      |                    |               |
| trant-submitted |      |      |                    |               |
| Studies         |      |      |                    |               |
+-----------------+------+------+--------------------+---------------+
| # Species       | ##   | ## L | **Endpoints        | **Classi      |
|                 |  NOA | OAEC | Affected**         | fication^1^** |
|                 | EC ( |      |                    |               |
|                 | ppm) | #    |                    | **(MRID)**    |
|                 |      | #  ( |                    |               |
|                 |      | ppm) |                    |               |
+-----------------+------+------+--------------------+---------------+
| ### Fresh       |      |      |                    |               |
| water Organisms |      |      |                    |               |
+-----------------+------+------+--------------------+---------------+
| Water flea      | 50   | 100  | Reduced growth,    | Core          |
|                 |      |      |                    |               |
| *(Daphnia       |      |      | Total \# of        | \(135642\)    |
| magna)*         |      |      | offspring          |               |
|                 |      |      |                    | Formulation   |
+-----------------+------+------+--------------------+---------------+
| #               |      |      |                    |               |
| ## Estuarine/ M |      |      |                    |               |
| arine organisms |      |      |                    |               |
+-----------------+------+------+--------------------+---------------+
| Mysid shrimp    | 0.7  | 1.7  | Parental mortality | Core          |
|                 |      |      |                    |               |
| *(Mysidopsis    |      |      |                    | \(135648\)    |
| bahia)*         |      |      |                    |               |
|                 |      |      |                    | Formulation   |
+-----------------+------+------+--------------------+---------------+
| Sheepshead      | 12.2 | 20.1 | Reduced larval     | Core          |
| minnow^2^       |      |      | survival           |               |
|                 |      |      |                    | \(135644\)    |
| *(Cyprinodon    |      |      |                    |               |
| varigetus)*     |      |      |                    | Formulation   |
+-----------------+------+------+--------------------+---------------+

^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 a.i.

[Aquatic Data from ECOTOX]{.underline}

The ECOTOX database was accessed, and no toxicity data for fomesafen
were located.

**[Terrestrial Plant Guideline Data]{.underline}**

Terrestrial plant guideline studies were submitted during the
development of this risk assessment. Data are shown below (Table 3), but
are considered provisional pending final data evaluation review.
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. The product is marketed as a control for broad-leafed
weeds. In some cases, calculated EC~25~s were below the concentrations
tested, so a NOAEC was not determined. The most sensitive endpoint, used
in the risk assessment, is the vegetative vigor EC~25~ for radish
(0.0016 lb ai/A).

+-----------------+------------+------+-------+--------+-------------+
| Table 3         |            |      |       |        |             |
| Terrestrial     |            |      |       |        |             |
| Plant Guideline |            |      |       |        |             |
| Data            |            |      |       |        |             |
+-----------------+------------+------+-------+--------+-------------+
| # Species       | ## C       | ## C | ## EC | **N    | **Classifi  |
|                 | ommon name | lass | ~25~  | OAEC** | cation^1^** |
|                 |            |      |       |        |             |
|                 |            |      | ##    | **(lb  | **(MRID)**  |
|                 |            |      |  (lb  | ai     |             |
|                 |            |      | ai/A) | /A))** |             |
+-----------------+------------+------+-------+--------+-------------+
| Vegetative      |            |      |       |        |             |
| Vigor           |            |      |       |        |             |
+-----------------+------------+------+-------+--------+-------------+
| ### R           | Radish     | D    | 0     | 0      | Su          |
| aphanus sativus |            |      | .0016 | .00098 | pplementary |
|                 |            |      |       |        |             |
|                 |            |      |       |        | \           |
|                 |            |      |       |        | (46673802\) |
+-----------------+------------+------+-------+--------+-------------+
| *Echinochloa    | Barnyard   | M    | 0.31  | 0.25   |             |
| crus-galli*     | grass      |      |       |        |             |
+-----------------+------------+------+-------+--------+-------------+
| Seedling        |            |      |       |        |             |
| emergence       |            |      |       |        |             |
+-----------------+------------+------+-------+--------+-------------+
| *Lycopersicon   | Tomato     | D    | 0.005 | ND     | Su          |
| esculentum*     |            |      |       |        | pplementary |
|                 |            |      |       |        |             |
|                 |            |      |       |        | \           |
|                 |            |      |       |        | (46673801\) |
+-----------------+------------+------+-------+--------+-------------+
| *Allium cepa*   | Onion      | M    | 0.089 | ND     |             |
+-----------------+------------+------+-------+--------+-------------+

**^1^** Provisional classification, pending final data evaluation
review.

Efficacy data (MRID 135656) were part of the data package submitted. 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). The two
concentrations bracket the currently proposed rates (0.42 and 0.54 kg
ai/ha). 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.

**[Avian and Small Mammal Guideline Data]{.underline}**

Guideline studies were available for birds (both dose and dietary), and
small laboratory mammals (dose). On the basis of both dose and dietary
values, fomesafen is practically non-toxic to birds and slightly toxic
to mammals (Table 4). Endpoints for female guinea pigs and mallard ducks
were used to develop risk quotients.

+---------------+----------+-------------+-----------+---------------+
| Table 4 Avian |          |             |           |               |
| and Small     |          |             |           |               |
| Mammal        |          |             |           |               |
| Guideline     |          |             |           |               |
| Data from     |          |             |           |               |
| Acute Studies |          |             |           |               |
+---------------+----------+-------------+-----------+---------------+
| # Species     | ## LC~5  | ## 95%      | **NOAEC   | **Classi      |
|               | 0~ (ppm) |  C.I. (ppm) | (ppm)**   | fication^1^** |
|               |          |             |           |               |
|               |          |             |           | **(MRID)**    |
+---------------+----------+-------------+-----------+---------------+
| #             |          |             |           |               |
| ## Acute dose |          |             |           |               |
+---------------+----------+-------------+-----------+---------------+
| Mallard duck  | \>5,000  | ND          | ND        | Core          |
|               |          |             |           |               |
|               | (pra     |             |           | \(163168\)    |
|               | ctically |             |           |               |
|               | no       |             |           |               |
|               | n-toxic) |             |           |               |
+---------------+----------+-------------+-----------+---------------+
| Rat           | F 1499   | (1302-1749) | 1219      | Minimum       |
|               |          |             |           |               |
|               | M 1858   | (1420-2546) | 975       | \(164901\)    |
|               |          |             |           |               |
|               | (        |             |           |               |
|               | slightly |             |           |               |
|               | toxic)   |             |           |               |
+---------------+----------+-------------+-----------+---------------+
| Mouse         | F 745    | (512-1286)  | 487       | Minimum       |
|               |          |             |           |               |
|               | M 766    | (525-1341)  | 312       | \(164901\)    |
|               |          |             |           |               |
|               | (        |             |           |               |
|               | slightly |             |           |               |
|               | toxic)   |             |           |               |
+---------------+----------+-------------+-----------+---------------+
| Guinea Pig    | F 607    | ND          | 244       | Minimum       |
|               |          |             |           |               |
|               | (        |             |           | \(164901\)    |
|               | slightly |             |           |               |
|               | toxic)   |             |           |               |
+---------------+----------+-------------+-----------+---------------+
| ###           |          |             |           |               |
| Acute dietary |          |             |           |               |
+---------------+----------+-------------+-----------+---------------+
| Bobwhite      | \>20,000 | ND          | 13,333    | Core          |
| quail         |          |             |           |               |
|               | (pra     |             |           | \(103022\)    |
|               | ctically |             |           |               |
|               | no       |             |           |               |
|               | n-toxic) |             |           |               |
+---------------+----------+-------------+-----------+---------------+
| Mallard duck  | \>20,000 | ND          | 20,000    | Core          |
|               |          |             |           |               |
|               | (pra     |             |           | \(163384\)    |
|               | ctically |             |           |               |
|               | no       |             |           |               |
|               | n-toxic) |             |           |               |
+---------------+----------+-------------+-----------+---------------+

^1^Data are from studies originally reviewed and classified in 1984.

ND-Not determined

Chronic guideline studies (Table 5) were available for birds (mallard
duck and bobwhite quail) and small laboratory mammals (rat). Bird
guideline studies did not establish a LOAEC, only determining that there
were no effects at the highest (mean-measured) concentration tested.
This 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 overestimate the risk
to birds. In some cases, calculated exposure is near or above the
maximum tested concentration.

+-----------+---------+-------+----------------------+---------------+
| Table 5   |         |       |                      |               |
| Avian and |         |       |                      |               |
| Small     |         |       |                      |               |
| Mammal    |         |       |                      |               |
| Guideline |         |       |                      |               |
| Data from |         |       |                      |               |
| Chronic   |         |       |                      |               |
| Studies   |         |       |                      |               |
+-----------+---------+-------+----------------------+---------------+
| # Species | ## NOAE | ##    | **Endpoint           | **Classi      |
|           | C (ppm) | LOAEC | Affected**           | fication^1^** |
|           |         |       |                      |               |
|           |         | **(p  |                      | **(MRID)**    |
|           |         | pm)** |                      |               |
+-----------+---------+-------+----------------------+---------------+
| Bobwhite  | 51      | ND    | None                 | Core          |
| quail     |         |       |                      |               |
|           |         |       |                      | \(135640\)    |
+-----------+---------+-------+----------------------+---------------+
| Mallard   | 46      | ND    | None                 | Core          |
| duck      |         |       |                      |               |
|           |         |       |                      | \(135639\)    |
+-----------+---------+-------+----------------------+---------------+
| Rat       | 250     | 1000  | Number of pups born  | Acceptable    |
|           |         |       | live, number of pups |               |
|           |         |       | surviving            | \(144862\)    |
+-----------+---------+-------+----------------------+---------------+

^1^Data are from studies originally reviewed and classified in 1984.

ND-Not determined

**[Terrestrial Insect Data]{.underline}**

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 μg ai/bee**,** and the acute contact
LD~50~ was \>100 μg 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.

[Terrestrial Data from ECOTOX]{.underline}

The ECOTOX database was accessed, and no toxicity data for fomesafen
were located.

**Incident Reports**

EFED maintains EIIS, a database containing reported incidents of damage
to non-target species caused by pesticide use. There are a total of 28
reported incidents for fomesafen, 27 of which are damage to agricultural
crops. Incidents reported cover a range of 9 years (1994-2002), but many
of them (54%) were reported in 2002. Corn was the crop most frequently
reported damaged, accounting for 21 out of the 24 cases for which the
specific crop was reported. In some cases (5) the fomesafen was applied
directly to the damaged crop, and the legality was classified as misuse
or accidental misuse. In other cases (17) the damaged was caused by
drift, legality of application 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.

There is one report of a fish kill. 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.

**[Exposure Characteristics]{.smallcaps}**

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 undergos slow
photodegradation in water

(t~1/2~= 49 to 289 days). Fomesafen is persistent (t~1/2~=9 to 99 weeks)
in aerobic soil and aquatic environments. However, it degrades rapidly
(t~1/2~\< 20 days) in anaerobic environments. The major degradation
product of fomesafen is
5-(2-chloro-α,α,α-trifluoro-p-tolyloxy)-N-methylsulphonyl-panthranilamide
(fomesafen amine). A minor degradation product is
5-(2-chloro-α,α,α-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
(t~1/2~= 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
were depurated during a 14-day depuration period.

**[Characteristics of Ecosystems Potentially at Risk]{.smallcaps}**

For typical crop applications, the ecosystem at risk is the field
itself, in terms of organisms that might be sprayed during application,
organisms affected by accumulation of 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 agricultural fields, pelagic and benthic elements 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.

Fomesafen is being proposed as a pre-plant, pre-emergence, and
post-emergence herbicide for use on broadleaf weeds, grasses, and
sedges, in snap beans, dry beans, and cotton. Methods of application are
ground spray (0.5 lb ai/A, cotton) and aerial spray (0.375 lb ai/A, 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. Maps 1, 2, and 3 show the locations of these crops
according to USDA crop data.

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height="6.523611111111111in"}

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**[Assessment Endpoints]{.smallcaps}**

Assessment endpoints are defined as "explicit expressions of the actual
environmental value that is to be protected." Defining an assessment
endpoint involves two steps: 1) identifying the valued attributes of the
environment that are considered to be at risk; and 2) operationally
defining the assessment endpoint in terms of an ecological entity (i.e.,
a community of fish and aquatic invertebrates) and its attributes (i.e.,
survival and reproduction). Therefore, selection of the assessment
endpoints is based on valued entities (i.e., ecological receptors), the
ecosystems potentially at risk, the migration pathways of pesticides,
and the routes by which ecological receptors are exposed to
pesticide-related contamination. The selection of clearly defined
assessment endpoints is important because they provide direction and
boundaries in the risk assessment for addressing risk management issues
of concern. Changes to assessment endpoints are typically estimated from
the available toxicity studies, which are used as the measures of
effects to characterize potential ecological risks associated with
exposure to a pesticide, such as paclobutrazol.

To estimate exposure concentrations, the ecological risk assessment
considers a single application at the maximum application rate to fields
that have vulnerable soils. The most sensitive toxicity endpoints are
used from surrogate test species to estimate treatment-related direct
effects on acute mortality and chronic reproductive, growth and survival
assessment endpoints. Toxicity tests are intended to determine effects
of pesticide exposure on birds, mammals, fish, terrestrial and aquatic
invertebrates, and plants. These tests include short-term acute,
sub-acute, and reproduction studies and are typically arranged in a
hierarchical or tiered system that progresses from basic laboratory
tests to applied field studies. The toxicity studies are used to
evaluate the potential of a pesticide to cause adverse effects, to
determine whether further testing is required, and to determine the need
for precautionary label statements to minimize the potential adverse
effects to non-target animals and plants.

Evaluation of ecological effects focuses initially on direct effects to
the groups of organisms residing in the ecosystems at risk, based on
ratios 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.

*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. Both acute and chronic effects are
considered.

*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.

**[Conceptual Model]{.smallcaps}**

In order for a chemical to pose an ecological risk, it must reach
ecological receptors in biologically significant concentrations. An
exposure pathway is the means by which a pesticide moves in the
environment from a source to an ecological receptor. For an ecological
exposure pathway to be complete, it must have a source, a release
mechanism, an environmental transport medium, a point of exposure for
ecological receptors, and a feasible route of exposure. The conceptual
model (**Figure 1**) depicts the potential pathways for ecological risk
associated with fomesafen use. The conceptual model provides an overview
of the expected exposure routes for organisms within the fomesafen
action area.

[Risk Hypothesis]{.smallcaps}

• Fomesafen deposited on plant surfaces may affect growth, survival, or
fecundity of birds and/or small mammals ingesting the affected
vegetation.

• Fomesafen accumulating in soil may be toxic to non-target plants.

• Fomesafen in runoff from treated areas may kill aquatic plants,
aquatic invertebrates, or fish.

• Fomesafen in runoff from treated areas may reduce populations of
aquatic plants, aquatic invertebrates, or fish, causing changes in the
community.

• Fomesafen in runoff from treated areas may accumulate in sediments,
resulting in chronic impacts to the benthic community.

• Fomesafen is expected to move from the application site by leaching
into groundwater and runoff into surface water. Use of water resources
with fomesafen occurrence as an irrigation source water may adversely
impact non-target plants.

**[Analysis Plan Options]{.smallcaps}**

The registration review screening level risk assessment is based on an
overview document compliant risk assessment for fomesafen use on cotton,
dry beans, and snap beans (Ecological Risk Assessment in Support of
Docket Preparation for Registration Review of Fomesafen (DP 306023),
January 18, 2006. .

**[Measures of Exposure]{.smallcaps}**

**[Aquatic Exposure]{.smallcaps}**

Tier II EFED aquatic exposure models use 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 no outflow with a constant volume (20 million
liters), and is intended to represent an upper-end occurrence
concentration.

**PRZM-EXAMS Modeling for Surface Water**

The aquatic exposure assessment for fomesafen was conducted to assess
use on soybeans and cotton. Soybeans were used a surrogate for dry beans
and snap beans, as EFED currently has no standard scenarios for these
crops. Standard scenarios were selected to assess runoff potential from
vulnerable use sites in MS (soybean and cotton), NC (cotton), and TX
(cotton). Input parameters for fomesafen were selected according to EFED
Input Parameter Guidance for PRZM/EXAMS[^1]. Input parameters are shown
in Table 6.

+---------------------------------+-------+------------+--------------+
| Table 6 Input Parameters for    |       |            |              |
| PRZM-EXAMS Modeling of          |       |            |              |
| Fomesafen on Cotton and         |       |            |              |
| Soybeans                        |       |            |              |
+---------------------------------+-------+------------+--------------+
| **Parameter**                   | **Va  | **         | **Source**   |
|                                 | lue** | Comments** |              |
+---------------------------------+-------+------------+--------------+
| Application Rate (kg a.i./ha)-  | 0.42  | Aerial     | Label^1^     |
| Cotton                          |       | Spray      |              |
+---------------------------------+-------+------------+--------------+
| Application Rate (kg a.i./ha)-  | 0.56  | Ground     | Label^1^     |
| Cotton                          |       | Spray      |              |
+---------------------------------+-------+------------+--------------+
| Application Rate (kg a.i/ha)-   | 0.42  | Aerial     | Label^1^     |
| Soybean                         |       | Spray      |              |
+---------------------------------+-------+------------+--------------+
| Molecular Weight (grams/mole)   | 420   |            | EPA 2020220  |
+---------------------------------+-------+------------+--------------+
| Solubility (mg/L)               | 1200  | \@pH= 7;   | MRID         |
|                                 |       | 20^0^c     | 45048207     |
+---------------------------------+-------+------------+--------------+
| Vapor Pressure (torr)           | \<    | @ 50^o^C   | HSDB         |
|                                 | 7.5x1 |            |              |
|                                 | 0^-7^ |            |              |
+---------------------------------+-------+------------+--------------+
| Henry's Constant (atm m^3^/mol) | 7.5   | Estimated  | HSDB         |
|                                 | x10   |            |              |
|                                 | ^-13^ |            |              |
+---------------------------------+-------+------------+--------------+
| Kd (L/kg)                       | 0.68  | Lowest     | Acc No.      |
|                                 |       | non-sand   | 259413       |
|                                 |       | K~d~       |              |
+---------------------------------+-------+------------+--------------+
| Aerobic Soil Metabolism         | 428.8 | Upper      | Acc No.      |
| Half-life (days)                |       | 90^th^     | 071059       |
|                                 |       | percentile |              |
|                                 |       | of mean^2^ | Acc. No.     |
|                                 |       |            | 00135660     |
+---------------------------------+-------+------------+--------------+
| Aerobic Aquatic Metabolism      | 115.7 | Upper      | Acc. No.     |
| Half-life (days)                |       | 90^th^     | 72158        |
|                                 |       | percentile |              |
|                                 |       | of mean^3^ |              |
+---------------------------------+-------+------------+--------------+
| Anaerobic Aquatic Metabolism    | S     | Co         | No Data      |
| Half-life (days)                | table | nservative | Available    |
|                                 |       | Assumption |              |
+---------------------------------+-------+------------+--------------+
| Photodegradation in Water       | 289   | \@pH=7     | MRID         |
| (days)                          |       |            | 40451101     |
+---------------------------------+-------+------------+--------------+
| Hydrolysis Half-life (days)     | S     | \@pH=7     | Acc No.      |
|                                 | table |            | 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.

For aerial applications (Table 7), peak 1 in 10 year estimated
environmental concentrations (EECs) ranged from 7.5 ppb (soybeans, MS)
to 12.2 ppb (cotton, TX). Chronic 1-in-10 year (21-day average and
60-day average) EECs ranged from 6.4 ppb (soybean, MS, 60-day average)
to 11.4 ppb (cotton, MS &TX, 21-day average).

  ------------ ----------- ----------- ---------- --------- --------- ---------
  Table 7                                                             
  PRZM-EXAMS                                                          
  EECs for                                                            
  Fomesafen at                                                        
  0.375 lb                                                            
  a.i/A^1^                                                            

  **Region**   **Crop**    **State**   **Peak**   **4       **21      **60
                                                  days**    days**    days**

                                       **μg/L                         
                                       (ppb)**                        

  1            Soybean     MS          7.462      7.382     7.133     6.443

  1            Cotton      MS          12.102     11.964    11.411    10.115

  1            Cotton      NC          9.856      9.728     9.201     8.067

  1            Cotton      TX          12.201     12.045    11.437    9.973
  ------------ ----------- ----------- ---------- --------- --------- ---------

1-Concentrations were derived for 0.375 lb ai/A using aerial
applications

Peak 1-in-10 year EECs for ground spray applications (Table 8) ranged
from 10.6 ppb (cotton, NC) to 15.1 ppb (cotton, MS). Chronic 1 in 10
year (21-day average and 60-day average) concentrations ranged from 8.6
ppb (cotton, MS, 60-day average) to 14.2 ppb (cotton, MS, 21-day
average).

  ------------ ----------- ----------- ---------- --------- --------- ---------
  Table 8                                                             
  PRZM-EXAMS                                                          
  EECs for                                                            
  Fomesafen at                                                        
  0.50 lb ai/A                                                        

  **Region**   **Crop**    **State**   **Peak**   **4       **21      **60
                                                  days**    days**    days**

                                       **μg/L**                       

  1            Cotton      MS          15.106     14.939    14.249    12.621

  1            Cotton      NC          10.609     10.471    9.905     8.680

  1            Cotton      TX          14.63      14.445    13.713    11.954
  ------------ ----------- ----------- ---------- --------- --------- ---------

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

**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 9. A groundwater monitoring study was
submitted (MRID 42247001), but the shallow groundwater wells were dry
during the study. Fomesafen was detected in soil porewater at
concentrations of 1 μg/L (at 4 months), up to 17 μg/L (at 1 month). It
was detected at a concentration of 1 μg/L in the medium- to deep-depth
wells.

+---------------------------------+-------+----------+---------------+
| Table 9 Input Parameters for    |       |          |               |
| SCIGROW Modeling for Fomesafen  |       |          |               |
+---------------------------------+-------+----------+---------------+
| **Parameter**                   | **Va  | **Co     | **Source**    |
|                                 | lue** | mments** |               |
+---------------------------------+-------+----------+---------------+
| Application Rate (kg a.i./ha)-  | 0.56  |          | Label^1^      |
| Cotton                          |       |          |               |
+---------------------------------+-------+----------+---------------+
| K~oc~ (L/kg)                    | 68    | Esti     | Acc No.       |
|                                 |       | mated^2^ | 259413        |
+---------------------------------+-------+----------+---------------+
| Aerobic Soil Metabolism         | 3     | Mean^3^  | Acc No.       |
| Half-life (days)                | 87.84 |          | 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 is not expected to exceed 6.68 μg/L. A
groundwater monitoring study was submitted (MRID 42247001), but the
shallow groundwater wells were dry during the study. Fomesafen was
detected in soil porewater at concentrations of 1 μg/L (at 4 months), up
to 17 μg/L (at 1 month). It was detected at a concentration of 1 μg/L in
the medium- to deep-depth wells.

Because fomesafen is expected to leach to groundwater, EFED has
calculated the maximum application rate of fomesafen from two inches of
irrigation water, using the following equations. This calculation
assumes that two inches (0.167 ft) of irrigation water is required for
optimum plant growth. The calculations are as follows:

43,560 ft^2^/A\* 0.167 ft irrigation water= 7,274 ft^3^ for 2 inches of
irrigation water/A

7,274 ft^3^ irrigation water/A\* 28.316846 liter/ft^3^=205,991.13 liters
of irrigation water/A

205,991.13 liter of irrigation water/A \*EEC g/L = fomesafen g/A

(fomesafen g/A)/ (10^6^) = fomesafen grams/A\*1lb/454 grams=fomesafen
lbs ai/A.

Based on two inches of irrigation and the SCIGROW estimate, the
application rate of fomesafen is estimated at 0.003 lbs ai/A. Using the
concentrations of 1 mg/L and 17mg/L (from the groundwater study) as
outer bounds, concentrations of fomesafen in irrigation water could
range from 0.0004-0.0077 lbs ai/A.

**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. A first-order decay model (A=A~o~e^-kt^) was used to
estimate fomesafen soil concentrations. The time period in the model (t)
was set to 730 days to represent alternate years applications. The upper
90^th^ percentile of the mean half-life (t~1/2~=428 days; k=0.00161950
days^-1^) was used to represent the microbial mediated decay rate of
fomesafen in soil. The starting concentration (A~0~ ) was set at the
label recommended application rate of 0.375 lbs ai/A for aerial
applications and 0.5 lbs ai/A for ground applications. 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.

Figure 2 illustrates the fomesafen concentrations in soil reach a
plateau after approximately 10 years regardless of the application rate.
Application rates of 0.375 lbs/A can theoretically result in a maximum
fomesafen concentration of 0.14 mg/kg. Higher application rates of 0.5
lbs ai/A can theoretically result in a maximum fomesafen concentration
of 0.19 mg/kg.

![](media/image5.wmf)

Figure 2 - Estimate of Fomesafen Loading in the Surface Soil (0-15 cm
depth) from alternate year applications of 0.375 lbs/A (solid line) and
0.5 lbs/A (dotted line)

**[Terrestrial Exposure]{.smallcaps}**

**[Avian]{.smallcaps}**

For birds, dose estimates for the 0.2 lb ai/A application rate range
from 0.87 mg/kg bwt (1000g frugivores, granivores, and insectivores) to
54.7 mg/kg bwt (20 g herbivores) (Table 10). At the 0.37 lb ai/A
application rate, estimated doses range from 1.64 (1000g frugivores,
granivores, and insectivores) to 102 (1000g fruit and pods). Dose
estimates for the 0.49 lb ai/A application rate range from 2.14 mg/kg
bwt (1000g frugivores, granivores, and insectivores) to 134 mg/kg bwt
(20 g herbivores).

+------------------------------------+----------+----------+----------+
| Table 10 Bird Dose Estimates       |          |          |          |
+------------------------------------+----------+----------+----------+
| # Feeding Categories               | **Kenaga |          |          |
|                                    | Upper    |          |          |
|                                    | Bound    |          |          |
|                                    | Dose     |          |          |
|                                    | (mg/kg   |          |          |
|                                    | bwt)**   |          |          |
+------------------------------------+----------+----------+----------+
|                                    | *        | **       | *        |
|                                    | *Small** | Medium** | *Large** |
|                                    |          |          |          |
|                                    | **(20    | **(100   | **(1000  |
|                                    | g)**     | g)**     | g)**     |
+------------------------------------+----------+----------+----------+
| *0.2 lb ai/A Appllication Rate     |          |          |          |
| (Alternative)*                     |          |          |          |
+------------------------------------+----------+----------+----------+
| Short grass                        | 54.67    | 31.17    | 13.96    |
+------------------------------------+----------+----------+----------+
| Tall grass                         | 25.06    | 14.29    | 6.40     |
+------------------------------------+----------+----------+----------+
| Broadleaf plants/small insects     | 30.75    | 17.54    | 7.85     |
+------------------------------------+----------+----------+----------+
| Fruits/pods/seeds/large insects    | 3.42     | 1.95     | 0.87     |
+------------------------------------+----------+----------+----------+
| *0.375 lb ai/A Application Rate*   |          |          |          |
+------------------------------------+----------+----------+----------+
| 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     |
+------------------------------------+----------+----------+----------+
| *0.50 lb ai/A Application Rate*    |          |          |          |
+------------------------------------+----------+----------+----------+
| 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     |
+------------------------------------+----------+----------+----------+

**Small** **Mammals**

For mammals dose estimates for the 0.2 lb ai/A application rate range
from 0.10 mg/kg bwt (1000g granivore) to 45.8 mg/kg bwt (20 g short
grass) (Table 11). At the 0.37 lb ai/A application rate, estimated doses
range from 0.19 (1000g granivore) to 85.8 (20 g short grass). Dose
estimates for the 0.49 lb ai/A application rate range from 0.25 mg/kg
bwt (1000g granivore) to 112 mg/kg bwt (20 g short grass).

+------------------------------------+----------+----------+----------+
| Table 11 Mammal Dose Estimates     |          |          |          |
+------------------------------------+----------+----------+----------+
| # Feeding Categories               | **Kenaga |          |          |
|                                    | Upper    |          |          |
|                                    | Bound    |          |          |
|                                    | Dose     |          |          |
|                                    | (mg/kg   |          |          |
|                                    | bwt)**   |          |          |
+------------------------------------+----------+----------+----------+
|                                    | *        | **       | *        |
|                                    | *Small** | Medium** | *Large** |
|                                    |          |          |          |
|                                    | **(15    | **(35    | **(1000  |
|                                    | g)**     | g)**     | g)**     |
+------------------------------------+----------+----------+----------+
| *0.2 lb ai/A Appllication Rate     |          |          |          |
| (Alternative)*                     |          |          |          |
+------------------------------------+----------+----------+----------+
| ### Herbivores/Insectivores        |          |          |          |
+------------------------------------+----------+----------+----------+
| Short grass                        | 45.76    | 31.63    | 7.33     |
+------------------------------------+----------+----------+----------+
| Tall grass                         | 20.98    | 14.50    | 3.36     |
+------------------------------------+----------+----------+----------+
| Broadleaf plants/small insects     | 25.74    | 17.79    | 4.13     |
+------------------------------------+----------+----------+----------+
| Fruits/pods/seeds/large insects    | 2.86     | 1.98     | 0.46     |
+------------------------------------+----------+----------+----------+
| ######## Granivores                |          |          |          |
+------------------------------------+----------+----------+----------+
| Fruits/pods/seeds/large insects    | 0.64     | 0.44     | 0.10     |
+------------------------------------+----------+----------+----------+
| *0.375 lb ai/A Application Rate*   |          |          |          |
+------------------------------------+----------+----------+----------+
| ### 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     |
+------------------------------------+----------+----------+----------+
| *0.50 lb ai/A Application Rate*    |          |          |          |
+------------------------------------+----------+----------+----------+
| ### 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     |
+------------------------------------+----------+----------+----------+

**Plants**

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.
TerrPlant estimates are shown in Table 12.

+-----------------------+-------------+----------------+--------------+
| Table 12 Terrestrial  |             |                |              |
| Plant Exposure        |             |                |              |
+-----------------------+-------------+----------------+--------------+
| # Application Method  | **Total     |                | **Drift EEC  |
|                       | Loading     |                | (lb ai/A)**  |
|                       | (Runoff     |                |              |
|                       | +Drift) (lb |                |              |
|                       | ai/A)**     |                |              |
+-----------------------+-------------+----------------+--------------+
|                       | ####### U   | **Wetland      | **All        |
|                       | pland areas | areas**        | areas**      |
+-----------------------+-------------+----------------+--------------+
| ###                   |             |                |              |
|  Use at 0.375 lb ai/A |             |                |              |
+-----------------------+-------------+----------------+--------------+
| Aerial                | 0.0263      | 0.0938         | 0.0188       |
+-----------------------+-------------+----------------+--------------+
| Ground                | 0.0113      | 0.0788         | 0.0038       |
+-----------------------+-------------+----------------+--------------+
| ##                    |             |                |              |
| # Use at 0.50 lb ai/A |             |                |              |
+-----------------------+-------------+----------------+--------------+
| Aerial                | 0.0343      | 0.1225         | 0.0245       |
+-----------------------+-------------+----------------+--------------+
| Ground                | 0.0147      | 0.1029         | 0.0049       |
+-----------------------+-------------+----------------+--------------+

**[Summary of Risks]{.smallcaps}**

**[Aquatic Risks]{.smallcaps}**

Fomesafen appears to be of relatively low toxicity to aquatic organisms,
both animals and plants in freshwater and estuarine/marine systems
(Table 13). Both acute and chronic effects were considered. 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 distance is dependent on application rate, application
methods, and weather conditions.

+---------------------+--------------+---------------+---------------+
| Table 13 Summary of |              |               |               |
| Aquatic RQs         |              |               |               |
+---------------------+--------------+---------------+---------------+
| # Taxa              | ## Acute RQ  | **Chronic     | **Endangered  |
|                     |              | RQ**^1^       | Species       |
|                     |              |               | RQ**^2^       |
+---------------------+--------------+---------------+---------------+
| *Use on Beans at    |              |               |               |
| 0.375 lb a.i./A (MS |              |               |               |
| scenario, aerial    |              |               |               |
| application)*       |              |               |               |
+---------------------+--------------+---------------+---------------+
| FW Aquatic Plants   | 0.06         | NA^1^         | 0.33          |
+---------------------+--------------+---------------+---------------+
| FW Aquatic          | \<0.001      | \<0.001       | \<0.001       |
| Invertebrates       |              |               |               |
+---------------------+--------------+---------------+---------------+
| Fish                | \<0.001      | NC            | \<0.001       |
+---------------------+--------------+---------------+---------------+
| SW Aquatic Plants   | 0.01         | NA^1^         | 0.008         |
+---------------------+--------------+---------------+---------------+
| SW Aquatic          | \<0.001      | 0.01          | \<0.001       |
| Invertebrates       |              |               |               |
+---------------------+--------------+---------------+---------------+
| SW Fish             | \<0.001      | \<0.001       | \<0.001       |
+---------------------+--------------+---------------+---------------+
| *Use on Cotton at   |              |               |               |
| 0.375 lb a.i./A (MS |              |               |               |
| scenario, aerial    |              |               |               |
| application)*       |              |               |               |
+---------------------+--------------+---------------+---------------+
| FW Aquatic Plants   | 0.10         | NA^1^         | 0.53          |
+---------------------+--------------+---------------+---------------+
| FW Aquatic          | \<0.001      | \<0.001       | \<0.001       |
| Invertebrates       |              |               |               |
+---------------------+--------------+---------------+---------------+
| FW Fish             | \<0.001      | NC            | \<0.001       |
+---------------------+--------------+---------------+---------------+
| SW Aquatic Plants   | 0.01         | NA^1^         | 0.013         |
+---------------------+--------------+---------------+---------------+
| SW Aquatic          | \<0.001      | 0.02          | \<0.001       |
| Invertebrates       |              |               |               |
+---------------------+--------------+---------------+---------------+
| SW Fish             | \<0.001      | \<0.001       | \<0.001       |
+---------------------+--------------+---------------+---------------+
| *Use on Cotton at   |              |               |               |
| 0.5 lb a.i./A (MS   |              |               |               |
| scenario, ground    |              |               |               |
| application)*       |              |               |               |
+---------------------+--------------+---------------+---------------+
| FW Aquatic Plants   | 0.13         | NA^1^         | 0.66          |
+---------------------+--------------+---------------+---------------+
| FW Aquatic          | \<0.001      | \<0.001       | \<0.001       |
| Invertebrates       |              |               |               |
+---------------------+--------------+---------------+---------------+
| FW Fish             | \<0.001      | NC            | \<0.001       |
+---------------------+--------------+---------------+---------------+
| SW Aquatic Plants   | 0.01         | NA^1^         | 0.016         |
+---------------------+--------------+---------------+---------------+
| SW Aquatic          | \<0.001      | 0.02          | \<0.001       |
| Invertebrates       |              |               |               |
+---------------------+--------------+---------------+---------------+
| SW Fish             | \<0.001      | 0.001         | \<0.001       |
+---------------------+--------------+---------------+---------------+

^1^ There are no chronic aquatic plants tests. ^2^ Endangered species RQ
for plants are calculated based on NOAEC. Endangered species RQ 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.

**[Terrestrial Risks]{.smallcaps}**

**[Avian]{.smallcaps}**

At the proposed application rate of 0.5 lb ai/A, no acute dose- or
dietary-based LOCs are exceeded for birds (Table 14). Chronic LOCs for
birds in three out of the four food categories (short grass, tall grass,
and broadleaf plants/small insects) are exceeded.

+------------------------+------+----+------+-------------+----------+
| Table 14 Avian RQ      |      |    |      |             |          |
| Summary 0.5 lb ai/A    |      |    |      |             |          |
+------------------------+------+----+------+-------------+----------+
| # Ris                  | ##   |    |      | ## A        | *        |
| k quotients based on K | Acut |    |      | cute dietar | *Chronic |
| enaga upper bound EECs | e do |    |      | y-based RQs | RQs**    |
|                        | se-b |    |      |             |          |
|                        | ased |    |      |             |          |
|                        |  RQs |    |      |             |          |
+------------------------+------+----+------+-------------+----------+
|                        | ##   | #  | ## 1 | #           | **All    |
|                        |  20g | #  | 000g | # All birds | birds**  |
|                        |      | 10 |      |             |          |
|                        |      | 0g |      |             |          |
+------------------------+------+----+------+-------------+----------+
| Short grass            | 0.05 | 0. | 0.01 | 0.01        | 2.56 ^c^ |
|                        |      | 02 |      |             |          |
+------------------------+------+----+------+-------------+----------+
| Tall grass             | 0.02 | 0. | 0.00 | 0.00        | 1.17 ^c^ |
|                        |      | 01 |      |             |          |
+------------------------+------+----+------+-------------+----------+
| Broadleaf plants/small | 0.03 | 0. | 0.00 | 0.00        | 1.44 ^c^ |
| insects                |      | 01 |      |             |          |
+------------------------+------+----+------+-------------+----------+
| Fruits/pods/seeds/lg   | 0.00 | 0. | 0.00 | 0.00        | 0.16 ^c^ |
| insects                |      | 00 |      |             |          |
+------------------------+------+----+------+-------------+----------+

^a^ exceeds acute risk LOC (0.5)

^b^ exceeds endangered species acute risk LOC (0.1)

^c^ exceeds chronic risk LOC (1.0)

At the proposed application rate of 0.375 lb ai/A, no acute dose- or
dietary-based RQs exceed any LOCs (Table 15). The chronic LOC is
exceeded for birds consuming the food categories of short grass and
broadleaf plants/small insects.

+------------------------+------+----+------+-------------+----------+
| Table 15 Avian RQ      |      |    |      |             |          |
| Summary: 0.375 lb ai/A |      |    |      |             |          |
+------------------------+------+----+------+-------------+----------+
| # Ris                  | ##   |    |      | ## A        | *        |
| k quotients based on K | Acut |    |      | cute dietar | *Chronic |
| enaga upper bound EECs | e do |    |      | y-based RQs | RQs**    |
|                        | se-b |    |      |             |          |
|                        | ased |    |      |             |          |
|                        |  RQs |    |      |             |          |
+------------------------+------+----+------+-------------+----------+
|                        | ##   | #  | ## 1 | #           | **All    |
|                        |  20g | #  | 000g | # All birds | birds**  |
|                        |      | 10 |      |             |          |
|                        |      | 0g |      |             |          |
+------------------------+------+----+------+-------------+----------+
| Short grass            | 0.04 | 0. | 0.01 | 0.00        | 1.96 ^c^ |
|                        |      | 02 |      |             |          |
+------------------------+------+----+------+-------------+----------+
| Tall grass             | 0.02 | 0. | 0.00 | 0.00        | 0.90     |
|                        |      | 01 |      |             |          |
+------------------------+------+----+------+-------------+----------+
| Broadleaf plants/small | 0.02 | 0. | 0.00 | 0.00        | 1.10 ^c^ |
| insects                |      | 01 |      |             |          |
+------------------------+------+----+------+-------------+----------+
| Fruits/pods/seeds/lg   | 0.00 | 0. | 0.00 | 0.00        | 0.12     |
| insects                |      | 00 |      |             |          |
+------------------------+------+----+------+-------------+----------+

^a^ exceeds acute risk LOC (0.5)

^b^ exceeds endangered species acute risk LOC (0.1)

^c^ exceeds chronic risk LOC (1.0)

**[Small mammals]{.smallcaps}**

At the proposed application rate of 0.50 lb ai/A, dose-based RQs exceed
the endangered species LOC for two size classes of mammals (15g and 35
g) consuming short grass (Table 16). Using the dose-based RQ, chronic
LOC is exceeded for mammals consuming the food categories of short grass
(all weights), tall grass (15g, 35g), and broadleaf plants/small insects
(15g, 35g). No chronic dietary based-RQs exceed any LOCs.

+-----------------+----+----+------+----+----+------+--------------+
| Table 16 Small  |    |    |      |    |    |      |              |
| Mammal RQ       |    |    |      |    |    |      |              |
| Summary: 0.50   |    |    |      |    |    |      |              |
| lb ai/A         |    |    |      |    |    |      |              |
+-----------------+----+----+------+----+----+------+--------------+
| # Risk Q        | #  |    |      | *  |    |      | **Chronic    |
| uotients based  | #  |    |      | *C |    |      | d            |
|                 | Ac |    |      | hr |    |      | ietary-based |
| # on Kenaga     | ut |    |      | on |    |      | RQs**        |
|                 | e  |    |      | ic |    |      |              |
| #               |    |    |      | ** |    |      |              |
| upper bound EEC | #  |    |      |    |    |      |              |
|                 | #  |    |      | ** |    |      |              |
|                 | do |    |      | do |    |      |              |
|                 | se |    |      | se |    |      |              |
|                 | -b |    |      | -b |    |      |              |
|                 | as |    |      | as |    |      |              |
|                 | ed |    |      | ed |    |      |              |
|                 |  R |    |      | R  |    |      |              |
|                 | Qs |    |      | Qs |    |      |              |
|                 |    |    |      | ** |    |      |              |
+-----------------+----+----+------+----+----+------+--------------+
|                 | #  | #  | #    | #  | ** | **   | **All        |
|                 | #  | #  | # 10 | #  | 35 | 1000 | mammals**    |
|                 | 15 | 35 | 00 g | 15 | g  | g**  |              |
|                 |  g |  g |      |  g | ** |      |              |
+-----------------+----+----+------+----+----+------+--------------+
| Short grass     | 0. | 0. | 0.06 | 4. | 3. | 1.87 | 0.47         |
|                 | 13 | 11 |      | 08 | 49 | ^c^  |              |
|                 | ^  | ^  |      | ^  | ^  |      |              |
|                 | b^ | b^ |      | c^ | c^ |      |              |
+-----------------+----+----+------+----+----+------+--------------+
| Tall grass      | 0. | 0. | 0.03 | 1. | 1. | 0.86 | 0.22         |
|                 | 06 | 05 |      | 87 | 60 |      |              |
|                 |    |    |      | ^  | ^  |      |              |
|                 |    |    |      | c^ | c^ |      |              |
+-----------------+----+----+------+----+----+------+--------------+
| Broadleaf       | 0. | 0. | 0.03 | 2. | 1. | 1.05 | 0.26         |
| plants/         | 07 | 06 |      | 30 | 96 | ^c^  |              |
|                 |    |    |      | ^  | ^  |      |              |
| small insects   |    |    |      | c^ | c^ |      |              |
+-----------------+----+----+------+----+----+------+--------------+
| Fru             | 0. | 0. | 0.00 | 0. | 0. | 0.12 | 0.03         |
| its/pods/seeds/ | 01 | 01 |      | 26 | 22 |      |              |
|                 |    |    |      |    |    |      |              |
| lg insects      |    |    |      |    |    |      |              |
+-----------------+----+----+------+----+----+------+--------------+
| Seeds           | 0. | 0. | 0.00 | 0. | 0. | 0.03 | NA           |
| (granivores)    | 00 | 00 |      | 06 | 05 |      |              |
+-----------------+----+----+------+----+----+------+--------------+

^a^ exceeds acute risk LOC (0.5)

^b^ exceeds endangered species acute risk LOC (0.1)

^c^ exceeds chronic risk LOC (1.0)

At the proposed application rate of 0.375 lb ai/A, no acute dose-based
RQs for mammals exceed any LOCs, although the RQ for small (15g) mammals
consuming short grass equals the endangered species LOC (Table 17).
Using the dose-based RQ, the chronic LOC is exceeded for mammals
consuming the food categories of short grass (all weights), tall grass
(15g, 35g), and broadleaf plants/small insects (15g, 35g).

+-----------------+----+----+------+----+----+------+--------------+
| Table 17 Small  |    |    |      |    |    |      |              |
| Mammal RQ       |    |    |      |    |    |      |              |
| Summary:        |    |    |      |    |    |      |              |
| 0.375lb ai/A    |    |    |      |    |    |      |              |
+-----------------+----+----+------+----+----+------+--------------+
| # Risk Q        | #  |    |      | *  |    |      | **Chronic    |
| uotients based  | #  |    |      | *C |    |      | d            |
|                 | Ac |    |      | hr |    |      | ietary-based |
| # on Kenaga     | ut |    |      | on |    |      | RQs**        |
|                 | e  |    |      | ic |    |      |              |
| #               |    |    |      | ** |    |      |              |
| upper bound EEC | #  |    |      |    |    |      |              |
|                 | #  |    |      | ** |    |      |              |
|                 | do |    |      | do |    |      |              |
|                 | se |    |      | se |    |      |              |
|                 | -b |    |      | -b |    |      |              |
|                 | as |    |      | as |    |      |              |
|                 | ed |    |      | ed |    |      |              |
|                 |  R |    |      | R  |    |      |              |
|                 | Qs |    |      | Qs |    |      |              |
|                 |    |    |      | ** |    |      |              |
+-----------------+----+----+------+----+----+------+--------------+
|                 | #  | #  | #    | #  | ** | **   | **All        |
|                 | #  | #  | # 10 | #  | 35 | 1000 | mammals**    |
|                 | 15 | 35 | 00 g | 15 | g  | g**  |              |
|                 |  g |  g |      |  g | ** |      |              |
+-----------------+----+----+------+----+----+------+--------------+
| Short grass     | 0  | 0. | 0.05 | 3  | 2. | 1.43 | 0.36         |
|                 | .1 | 08 |      | .1 | 67 | ^c^  |              |
|                 | 0^ |    |      | 2^ | ^  |      |              |
|                 | b^ |    |      | c^ | c^ |      |              |
+-----------------+----+----+------+----+----+------+--------------+
| Tall grass      | 0. | 0. | 0.02 | 1. | 1. | 0.66 | 0.17         |
|                 | 05 | 04 |      | 43 | 22 |      |              |
|                 |    |    |      | ^  | ^  |      |              |
|                 |    |    |      | c^ | c^ |      |              |
+-----------------+----+----+------+----+----+------+--------------+
| Broadleaf       | 0. | 0. | 0.03 | 1. | 1. | 0.80 | 0.20         |
| plants/         | 06 | 05 |      | 76 | 50 |      |              |
|                 |    |    |      | ^  | ^  |      |              |
| small insects   |    |    |      | c^ | c^ |      |              |
+-----------------+----+----+------+----+----+------+--------------+
| Fru             | 0. | 0. | 0.00 | 0. | 0. | 0.09 | 0.20         |
| its/pods/seeds/ | 01 | 01 |      | 20 | 17 |      |              |
|                 |    |    |      |    |    |      |              |
| lg insects      |    |    |      |    |    |      |              |
+-----------------+----+----+------+----+----+------+--------------+
| Seeds           | 0. | 0. | 0.00 | 0. | 0. | 0.02 | NA           |
| (granivores)    | 00 | 00 |      | 04 | 04 |      |              |
+-----------------+----+----+------+----+----+------+--------------+

^a^ exceeds acute risk LOC (0.5)

^b^ exceeds endangered species acute risk LOC (0.1)

^c^ exceeds chronic risk LOC (1.0)

**[Plants]{.smallcaps}**

For both proposed uses of fomesafen, ground application at 0.5 lb ai/A
and aerial application at 0.375 lb ai/A, total loading RQs exceeded the
acute plant risk LOC (1) for both monocots and dicots in adjacent
wetland areas but not in upland areas (Table 18). Drift-based RQs were
exceeded for dicots in all adjacent areas. LOC exceedences for acute
risk to endangered plants followed the same pattern, but were of greater
magnitude. RQs based on the two alternative ground application scenarios
(0.375 lb ai/A and 0.2 lb ai/A) were also generated. At both these
rates, there were no exceedences for monocots. RQs for both total
loading to wetland areas and drift only exceeded the acute risk and
endangered species acute risk LOCs for dicots.

+--------------+---------+--------+-------+---------+---+------+-------+
| Table 18     |         |        |       |         |   |      |       |
| Terrestrial  |         |        |       |         |   |      |       |
| Plant Risk   |         |        |       |         |   |      |       |
| Quotients    |         |        |       |         |   |      |       |
| Based on     |         |        |       |         |   |      |       |
| TerrPlant    |         |        |       |         |   |      |       |
+--------------+---------+--------+-------+---------+---+------+-------+
| # Applic     | **Total |        | ##### |         | * |      |       |
| ation Method | Loading |        | ## ** |         | * |      |       |
|              | RQ      |        | Total |         | D |      |       |
|              | (S      |        |  Load |         | r |      |       |
|              | eedling |        | ing R |         | i |      |       |
|              | emerg   |        | Q (Se |         | f |      |       |
|              | ence)** |        | edlin |         | t |      |       |
|              |         |        | g Eme |         | R |      |       |
|              |         |        | rgenc |         | Q |      |       |
|              |         |        | e)**  |         | * |      |       |
|              |         |        |       |         | * |      |       |
|              |         |        |       |         |   |      |       |
|              |         |        |       |         | * |      |       |
|              |         |        |       |         | * |      |       |
|              |         |        |       |         | ( |      |       |
|              |         |        |       |         | V |      |       |
|              |         |        |       |         | e |      |       |
|              |         |        |       |         | g |      |       |
|              |         |        |       |         | e |      |       |
|              |         |        |       |         | t |      |       |
|              |         |        |       |         | a |      |       |
|              |         |        |       |         | t |      |       |
|              |         |        |       |         | i |      |       |
|              |         |        |       |         | v |      |       |
|              |         |        |       |         | e |      |       |
|              |         |        |       |         | v |      |       |
|              |         |        |       |         | i |      |       |
|              |         |        |       |         | g |      |       |
|              |         |        |       |         | o |      |       |
|              |         |        |       |         | r |      |       |
|              |         |        |       |         | ) |      |       |
|              |         |        |       |         | * |      |       |
|              |         |        |       |         | * |      |       |
+--------------+---------+--------+-------+---------+---+------+-------+
|              | ###     |        | **We  |         | * |      |       |
|              | #### ** |        | tland |         | * |      |       |
|              | Upland  |        | ar    |         | A |      |       |
|              | areas** |        | eas** |         | l |      |       |
|              |         |        |       |         | l |      |       |
|              |         |        |       |         | a |      |       |
|              |         |        |       |         | r |      |       |
|              |         |        |       |         | e |      |       |
|              |         |        |       |         | a |      |       |
|              |         |        |       |         | s |      |       |
|              |         |        |       |         | * |      |       |
|              |         |        |       |         | * |      |       |
+--------------+---------+--------+-------+---------+---+------+-------+
|              | Monocot | Dicot  | Mo    | Dicot   | M |      | Dicot |
|              |         |        | nocot |         | o |      |       |
|              |         |        |       |         | n |      |       |
|              |         |        |       |         | o |      |       |
|              |         |        |       |         | c |      |       |
|              |         |        |       |         | o |      |       |
|              |         |        |       |         | t |      |       |
+--------------+---------+--------+-------+---------+---+------+-------+
| ######       |         |        |       |         |   |      |       |
| # Acute risk |         |        |       |         |   |      |       |
+--------------+---------+--------+-------+---------+---+------+-------+
| ### Use at 0 |         |        |       |         |   |      |       |
| .2 lb ai/A ( |         |        |       |         |   |      |       |
| alternative) |         |        |       |         |   |      |       |
+--------------+---------+--------+-------+---------+---+------+-------+
| Ground       | 0.07    | 0.08   | 0.47  | 0.53    | 0 |      | 2.04  |
|              |         |        |       |         | . |      | ^a^   |
|              |         |        |       |         | 0 |      |       |
|              |         |        |       |         | 1 |      |       |
+--------------+---------+--------+-------+---------+---+------+-------+
| ### Use at 0 |         |        |       |         |   |      |       |
| .375 lb ai/A |         |        |       |         |   |      |       |
+--------------+---------+--------+-------+---------+---+------+-------+
| Aerial       | 0.29    | 0.33   | 1.05  | 1.19    | 0 |      | 11.72 |
|              |         |        | ^a^   | ^a^     | . |      | ^a^   |
|              |         |        |       |         | 0 |      |       |
|              |         |        |       |         | 6 |      |       |
+--------------+---------+--------+-------+---------+---+------+-------+
| Ground       | 0.13    | 0.14   | 0.88  | 1.00    | 0 |      | 2.34  |
| (            |         |        |       | ^a^     | . |      | ^a^   |
| alternative) |         |        |       |         | 0 |      |       |
|              |         |        |       |         | 1 |      |       |
+--------------+---------+--------+-------+---------+---+------+-------+
| ### Use at   |         |        |       |         |   |      |       |
|  0.5 lb ai/A |         |        |       |         |   |      |       |
+--------------+---------+--------+-------+---------+---+------+-------+
| Ground       | 0.17    | 0.19   | 1.16  | 1.30    | 0 |      | 3.06  |
|              |         |        | ^a^   | ^a^     | . |      | ^a^   |
|              |         |        |       |         | 0 |      |       |
|              |         |        |       |         | 2 |      |       |
+--------------+---------+--------+-------+---------+---+------+-------+
| #            |         |        |       |         |   |      |       |
| ###### Endan |         |        |       |         |   |      |       |
| gered specie |         |        |       |         |   |      |       |
| s acute risk |         |        |       |         |   |      |       |
+--------------+---------+--------+-------+---------+---+------+-------+
| ### Use at 0 |         |        |       |         |   |      |       |
| .2 lb ai/A ( |         |        |       |         |   |      |       |
| alternative) |         |        |       |         |   |      |       |
+--------------+---------+--------+-------+---------+---+------+-------+
| Ground       | 0.07    | 0.08   | 0.47  | 0.53    |   | 0.01 | 1.25  |
|              |         |        |       |         |   |      | ^a^   |
+--------------+---------+--------+-------+---------+---+------+-------+
| ### Use at 0 |         |        |       |         |   |      |       |
| .375 lb ai/A |         |        |       |         |   |      |       |
+--------------+---------+--------+-------+---------+---+------+-------+
| Aerial       | 0.29    | 0.33   | 1.05  | 1.19    |   | 0.08 | 19.13 |
|              |         |        | ^a^   | ^a^     |   |      | ^a^   |
+--------------+---------+--------+-------+---------+---+------+-------+
| Ground       | 0.13    | 0.14   | 0.88  | 1.00    |   | 0.02 | 3.83  |
| (            |         |        |       | ^a^     |   |      | ^a^   |
| alternative) |         |        |       |         |   |      |       |
+--------------+---------+--------+-------+---------+---+------+-------+
| ### Use at   |         |        |       |         |   |      |       |
|  0.5 lb ai/A |         |        |       |         |   |      |       |
+--------------+---------+--------+-------+---------+---+------+-------+
| Ground       | 0.17    | 0.19   | 1.16  | 1.30    |   | 0.02 | 5.00  |
|              |         |        | ^a^   | ^a^     |   |      | ^a^   |
+--------------+---------+--------+-------+---------+---+------+-------+

^a^ Exceeds or equals LOC of 1

**[Future Decisions]{.smallcaps}**

The Agency does not foresee requiring any additional ecological effects
or environmental fate data listed in 40 CFR Part 158 prior to support
current assessments. The Agency is re-reviewing environmental fate
studies for fomesafen. These studies were re-reviewed because there was
no documented assessment of degradation kinetics. The re-reviewed
studies are not expected to alter the interpretation on the persistence
of fomesafen in aquatic and soil environments. More importantly, the
Agency needs to conduct an endangered species assessment due to the high
phytoxicity of fomesafen.

[^1]: ^1^ **Guidance for Selecting Input Parameters in Modeling the
    Environmental Fate and Transport of Pesticides. Version II,
    2/28/02.**