Frond density

EC50 > 0.76 mg total a.i./L

NOAEC: 0.41 mg total a.i./L

Growth rate

EC50 > 0.76 mg total a.i./L

NOAEC: 0.41 mg total a.i./L

Most sensitive endpoint: biomass based on NOAEC

Endpoint(s) affected: biomass, frond density, growth rate	47267511
Supplemental (do not use in risk estimation)

Non-Vascular Aquatic Plants

Cyanobacteria (blue-green algae)

Anabaena flos-aquae	94.2	Tier II study

96 hour static study

3 reps.

Initial measured: <0.04 (negative, solvent), 0.0883, 0.139, 0.217,
0.580, and 0.862 mg a.i./L	Biomass (area under growth curve), cell
density, growth rate

EC50 > 0.862 mg total a.i./L

≥ 0.862 mg total a.i./L

Endpoint(s) affected: none.	47267512	Supplemental (do not use in risk
estimation)

Marine Diatom

Skeletonema costatum	94.2	Tier II study

96 hour static study

3 reps.

Initial measured: <0.04 (negative, solvent), 0.0509, 0.109, 0.214,
0.272, and 0.680 mg a.i./L	Biomass (area under growth curve)

EC50: 0.57 (0.38-0.85) mg total a.i./L

NOAEC: 0.0509 mg total a.i./L

Cell density

EC50 > 0.680 mg total a.i./L

NOAEC: 0.272 mg total a.i./L

Growth rate

EC50 > 0.680 mg total a.i./L

NOAEC: 0.272 mg total a.i./L

Most sensitive endpoint: biomass

Endpoint(s) affected: biomass, cell density, growth rate	47267513
Supplemental (do not use in risk estimation)

Freshwater Diatom

Navicula pelliculosa	94.2	Tier II study

96 hour static study

4 reps.

Initial measured: <0.04 (negative, solvent), 0.0761, 0.154, 0.276,
0.432, and 0.914 mg a.i./L	Biomass (area under growth curve)

EC50 > 0.914 mg total a.i./L

NOAEC: 0.432 mg total a.i./L

Cell density

EC50 > 0.914 mg total a.i./L

NOAEC: ≥0.914 mg total a.i./L

Growth rate

EC50 > 0.914 mg total a.i./L

NOAEC: ≥0.914 mg total a.i./L

Endpoint(s) affected: biomass based on NOAEC	47267514	Supplemental (do
not use in risk estimation)

Green Algae

Pseudokirchneriella subcapitata	97.1	Tier I study

72 hour static study

6 reps. (negative, solvent controls); 3 reps. (treatments)

Mean-measured: <0.498 (negative, solvent), 60, 123, 232, 472, and 870
g a.i./L	Biomass (area under growth curve)

EC50: 0.71 (0.65-0.77) mg total a.i./L

NOAEC: 0.23 mg total a.i./L

Cell density

EC50: 0.74 (0.67-0.82) mg total a.i./L

NOAEC: 0.23 mg total a.i./L

Growth rate

EC50 > 0.87 mg total a.i./L

NOAEC: 0.23 mg total a.i./L

Most sensitive endpoint: biomass

Endpoint(s) affected: biomass, cell density, growth rate	47267515
Supplemental (do not use in risk estimation)

Metabolites/ Degradates

Non-Vascular Aquatic Plants

Algae

Pseudokirchneriella subcapitata	99.5	CL 375816 (Metabolite of BAS 560 F)

Tier I study

72 hour static study

5 reps. (negative control); 3 reps. (treatments)

Mean-measured: ND (negative), 6.50, 12.66, 25.80, 51.45, and 101.92 mg
a.i./L	Biomass (area under growth curve), Chlorophyll-a, and Growth rate

EC50 > 101.9 mg total a.i./L

NOAEC ≥ 101.9 mg total a.i./L

Endpoint(s) affected: none.	47267516	Supplemental (do not use in risk
estimation)

Algae

Pseudokirchneriella subcapitata	98.2	CL 4084564 (Metabolite of BAS 560
F)

Tier I study

72 hour static study

5 reps. (negative control); 3 reps. (treatments)

Mean-measured: ND (negative), 3.21, 6.28, 9.9, 18.57, 38.78, and 58.03
mg a.i./L	Chlorophyll-a

EC50: 24 (21-27) mg total a.i./L

NOAEC: 9.9 mg total a.i./L

Biomass (area under growth curve)

EC50: 26 (22-30) mg total a.i./L

NOAEC: 9.9 mg total a.i./L

Growth rate

EC50: 44 (40-47) mg total a.i./L

NOAEC: 9.9 mg total a.i./L

Most sensitive endpoint: chlorophyll-a

Endpoint(s) affected: chlorophyll-a, biomass, and growth rate	47267517
Supplemental (do not use in risk estimation)

Formulations

Non-Vascular Aquatic Plants

Green Algae Pseudokirchneriella subcapitata	24.7	BAS 560 00F (SF 10358,
RLF 12359)

Tier I study

72 hour static study

6 reps. (negative control); 3 reps. (treatments)

Initial mean-measured: <0.05 (negative), 0.188, 0.371, 0.716, 1.383,
2.717, and 5.681 mg a.i./L	Cell density

EC50: 0.66 (0.47-0.91) mg total a.i./L

NOAEC: 0.188 mg total a.i./L

Biomass (area under growth curve)

EC50: 0.73 (0.53-0.99) mg total a.i./L

NOAEC: 0.188 mg total a.i./L

Growth rate

EC50: 5.2 (4.4-6.2) mg total a.i./L

NOAEC: 0.188 mg total a.i./L

Most sensitive endpoint: cell density

Endpoint(s) affected: cell density, biomass, growth rate	47267607
Supplemental (do not use in risk estimation)

2. Terrestrial Effects Characterization

a. Terrestrial Animals

(1) Acute Effects

Birds – Technical

The acute avian oral studies (MRID 47267502, 47267503) on 23-week old
Northern bobwhite quail (Colinus virginianus) and 20-week old mallard
duck (Anas platyrhynchos), respectively, assessed over 14 days are
classified as acceptable.  AC 375839 Technical was administered to the
birds via gelatin capsules at nominal levels of 0 (vehicle control),
400, 600, 900, 1350, and 2025 mg ai/kg bw (limit dose).  The 14-day
acute oral LD50 was >2025 mg ai/kg bw (>limit dose).  The 14-day NOAEL
was 2025 mg ai/kg bw, as there were no mortalities, clinical signs of
toxicity, or treatment-related effects on body weight or food
consumption during the 14-day study.  In addition, no toxicological
effects were observed at necropsy.  AC 375839 Technical (metrafenone)
would be classified as practically non-toxic to young adult Northern
bobwhite quail (C. virginianus) as well as to young adult mallard duck
(A. platyrhynchos) in accordance with the classification system of the
U.S. EPA.

The acute avian dietary studies (MRID 47267504, 47267505) on 11-day old
Northern bobwhite quail (C. virginianus) and 9-day old mallard duck (A.
platyrhynchos), respectively, assessed over 8 days are classified as
acceptable. AC 375839 Technical was administered to the birds in the
diet at nominal concentrations of 0 (negative control), 100, 270, 729,
1968, and 5314 mg ai/kg diet (adjusted for purity).  Mean-measured
concentrations were <3.6 (<LOD, control), 98, 262, 809, 2130, and 6070
mg ai/kg diet, respectively.  The 8-day acute dietary LC50 was >6070 mg
ai/kg diet.  Given there was no dose-response, the NOAEC was the highest
concentration tested, 6070 mg a.i./kg diet. There were no
treatment-related mortalities, clinical signs of toxicity, or effects on
food consumption.  Some gross pathological changes were observed.  AC
375839 Technical (metrafenone) would be classified as practically
non-toxic to juvenile bobwhite quail (C. virginianus) as well as to
juvenile mallard duck (A. platyrhynchos) on an acute dietary basis, in
accordance with the classification system of the U.S. EPA.

Table 24.  Avian Acute Toxicity Data

Common Name	%AI	Study parameters	LD50/LC50 NOAEL/

LOAEL	MRID	Classification/Category

Technical AC 375839 (a.k.a. BAS 560F)

Northern Bobwhite Quail  Colinus virginianus	95.86	Acute oral study

5 birds/sex/dose level

14 day observation period

Nominal: 0 (vehicle), 400, 600, 900, 1350, and 2025 mg a.i./kg bw

	LD50 > 2025 mg a.i./kg bw

NOAEL: 2025 mg/kg bw

Probit slope: N/A

Endpoint(s) affected: none.	47267502	Acceptable/

Practically non-toxic1

Mallard Duck

Anas platyrhynchos	95.86	Acute oral study

5 birds/sex/dose level

14 day observation period

Nominal: 0 (vehicle), 400, 600, 900, 1350, and 2025 mg a.i./kg bw 	LD50
>2025 mg a.i/kg bw

NOAEL:  2025 mg a.i./kg bw

Probit slope: N/A

Endpoint(s) affected: none.	47267503	Acceptable/

Practically non-toxic1

Northern Bobwhite Quail  Colinus virginianus	95.86	Acute dietary study

12 birds per rep.(neg. control & treatment); 3 reps. (neg. control), 1
rep. per treatment

5 days on treatment, 3 additional days observation

Mean-measured: <3.6 (neg. control), 98, 262, 809, 2130, and 6070 mg
a.i./kg diet	LC50 >6070 mg a.i./kg diet

NOAEC: 6070 mg a.i./kg diet

LOAEC >6070 mg a.i./kg diet

Issues3: body weight change (significant reduction in body weight gain
(39%, relative to Control 1) at the 262 mg ai/kg diet level). However,
no concentration-response was observed so it may not be biologically
significant.	47267504	Acceptable/

Practically non-toxic2

Mallard Duck

Anas platyrhynchos	95.86	Acute dietary study

12 birds per rep.(neg. control & treatment); 3 reps. (neg. control), 1
rep. per treatment

5 days on treatment, 3 additional days observation

Mean-measured: <3.6 (neg. control), 98, 262, 809, 2130, and 6070 mg
a.i./kg diet	LC50 > 6070 mg a.i./kg diet

NOAEC:  6070 mg a.i./kg diet

LOAEC >6070 mg a.i./kg diet

Issues3: body weight change (significant reduction in body weight gain
(19%, relative to controls) at the 262 mg ai/kg diet level). However, no
concentration-response was observed so it may not be biologically
significant.	47267505	Acceptable/

Practically non-toxic2

1 Based on LD50 (mg/kg) <10 very highly toxic; 10-50 highly toxic;
51-500 moderately toxic; 501-2000 slightly toxic; >2000 practically
nontoxic

2  Based on LC50 (mg/kg) <50 very highly toxic; 50-500 highly toxic;
501-1000 moderately toxic; 1001-5000 slightly toxic; >5000 practically
nontoxic

3 The Northern bobwhite and mallard duck acute dietary studies were
conducted at the same time in the same laboratory using the same feed.
Therefore, the observance of body weight change at the same
concentration level (262 mg a.i./kg diet) in both studies calls into
question the validity of the effect as a result of the chemical versus
some other factor.

Mammals  - Technical

In an acute oral toxicity study (MRID 47267522), three per sex, fasted,
young adult C57BL mice [(age: 8- 13 weeks old, wt. males 23.0-25.7g,
females 17.0-18.7g)] were given a single oral dose of the test material
(BAS 560 F)  prepared in 0.5% CMC solution in doubly distilled water in
a sequential manner at a dose level of 2000 mg/kg bw by gavage and
observed for 14 days. The three females were dosed in step 1, and the
three males in step 2. The oral LD50 is > 2000 mg/kg in mice which
classifies the product (metrafenone technical) in EPA Toxicity Category
III for oral toxicity.

One male animal died on Day 4. This animal showed poor general health,
dyspnea, tremor, piloerection and sunken flanks. The dead mouse showed
discoloration of the lungs, and ulcer/erosion in stomach. All other male
and female animals survived showed no obnormalities, and gained body
weight during the first week post-exposure.  No gross abnormalities were
noted for any of the surviving animals when necropsied at the
termination.

Mammals – Formulation

In an acute oral toxicity study (MRID 47267609), 5/sex of
Sprague-Dawley derived (Crl:CD(SD)BR) albino rats (age: 8 weeks; weight:
206-229 g males and 165-184 g females) were given a single oral dose of
AC 375839 300 g/L SC (RLF12359) (Lot No. R2066-048; 294 g/L and 25.21%
AC 375839; density 1.19 g/mL; pH 6.6; viscous beige liquid) as received
at a dose of 5000 mg/kg bw administered by oral gavage.  The amount of
test solution to be administered was calculated for each animal. Animals
were observed for clinical signs of toxicity and mortality several times
on the day of dosing and daily for 14 days.  Individual body weights
were recorded prior to dosing (day 0) and on days 7 and 14. A gross
necropsy examination was performed on all animals at scheduled
euthanasia. All animals survived and gained weight. No clinical signs of
toxicity were observed. No gross pathological findings were observed at
necropsy. The oral LD50 is > 5000 mg/kg in rats which classifies the
product (metrafenone formulation) in EPA Toxicity Category IV for oral
toxicity.

Table 25.  Mammalian Acute Toxicity Data

Common Name	%AI	Study parameters	LD50 /NOAEL	MRID
Classification/Category

Technical AC 375839 (a.k.a. BAS 560F)

Mouse	94.2	Acute oral study

2000 mg technical/kg bw (limit test) administered by gavage

3/sex/dose level

14-day observation period	Acute oral LD50 >2000 mg technical/kg bw (F,
M, both)2

NOAEL:  No NOAEL

LOAEL: No LOAEL	47267522	Acceptable/

Practically non-toxic1

Formulation

Laboratory albino rat	25.21%; AC 375839 300 g/ L SC (RLF 12359)	Acute
oral study

5000 mg form/kg bw (limit test) administered by gavage

5/sex/dose level

14-day observation period	Acute oral LD50 >5000 mg form/kg bw (F, M,
both) [> 1,260.5 mg a.i./kg bw] 3

NOAEL:  No NOAEL

LOAEL: No LOAEL	47267609	Acceptable4/

Practically non-toxic1

1 Based on LD50 (mg/kg) <10 very highly toxic; 10-50 highly toxic;
51-500 moderately toxic; 501-2000 slightly toxic; >2000 practically
nontoxic

2 One male animal died on Day 4. This animal showed poor general health,
dyspnea, tremor, piloerection and sunken flanks. The dead mouse showed
discoloration of the lungs, and ulcer/erosion in stomach.

3 All animals survived and gained weight. No clinical signs of toxicity
were observed. No gross pathological findings were observed at necropsy.

4 The study satisfies the OECD Guideline 401, which is no longer
considered an acceptable protocol. The preferred protocol is OECD 425:
Acute Oral Toxicity-Up-and-Down Procedure.

Terrestrial Invertebrates – Technical

The terrestrial invertebrate study on honey bees (Apis mellifera, MRID
47267508) classified as acceptable. The contact test had 4% mortality in
the negative and solvent controls and 0% mortality in the 100 µg
a.i./bee level by 48 hours; there were no sub-lethal effects in the
contact test. The oral test also had 4% mortality in the negative
control, 2% mortality in the solvent control, and 2% mortality in the
114 µg a.i./bee level at 24 and 48 hours; sub-lethal effects were 0% in
the negative control, 2% in the solvent control, and 6% in the 114 µg
a.i./bee level only at 4 hours.

In a 14 day acute limit toxicity study, earthworms (Eisenia fetida, MRID
47267518) were exposed to AC 375839 at a nominal concentration of 1000
mg a.i./kg dry weight of artificial soil. No concurrent reference
chemical test was conducted in this study. The report indicated that the
experiment was carried out in accordance with OECD 207. However, only
one concentration was tested which did not fulfill the requirement of
the guideline. No earthworm mortality was observed in the water control
or test substance treatment. There was one mortality in the acetone
control group. The 14 day LC50 was > 1000 mg a.i./kg dry soil, the
concentration tested. No significant difference in earthworm burrowing
time (i.e., time needed for 10 earthworms to burrow into the soil after
placement on soil surface) was observed. The average weight loss between
Day 0 and Day 14 was 20.6, 3.5 and 39.7 mg in the test groups of water
control, acetone control, and test substance treatment, respectively.
There was a significant difference in weight change between acetone
control and test substance treatment. However, there was no significant
difference between the water control and the test substance. Therefore,
the sub-lethal effect of AC 375839 at a concentration of 1000 mg a.i./kg
dry wt soil on weight loss is uncertain. The end-point toxicity
concentration of AC 375839 can not be determined from this study,
however, it is considered to be non-lethal to earthworms up to a
concentration of 1000 mg a.i./kg dry soil. No other observable compound
related toxicity effect was reported.

Terrestrial Invertebrates – Metabolites

In a 14 day acute toxicity study, earthworms (E. fetida, MRID 47267519)
were exposed to CL 377160 at nominal concentrations of 0, 198, 296, 444,
667, and 1000 mg CL 377160/kg dry weight of artificial soil. No
concurrent reference chemical test was conducted in this study, however,
the facility conducts annual test with 2-chloroacetamide in a
concentration range of 0 – 30 mg/kg dw of soil. The experiment was
carried out in accordance with OECD 207. There were no observable
compound related toxicity effects. No sub-lethal toxicity, specifically
body weight loss, was observed. Calculations using the mean body weight
for each treatment against the mean initial body weight (440 mg each)
showed that there were body weight gains of 3.3%, 5.3%, 7.7%, 10.5%,
4.6%, and 2.7% for the treatments of 0, 198, 296, 444, 667, 1000 mg/kg
dry soil weight. No other toxicity effect was reported. In addition, no
earthworm mortality was observed in the water control or in test
substance treatments. The 14 day LC50 was > 1000 mg/kg dw of soil.  The
14 day NOEC, based on mortality and body weight, was 1000 mg/kg dw of
soil, the highest concentration tested. The CL 377160 is considered to
be non-toxic to earthworms up to a concentration of 1000 mg/kg dw of
soil based on this study. However, a freeze storage stability study
submitted by the applicant (PMRA # 1620213) showed that CL 377160
rapidly bound and degraded in soils even at – 5 ºC. Therefore, the
LC50 obtained from this study is uncertain and the actual LC50 could be
lower.

Terrestrial Invertebrates – Formulations

The terrestrial invertebrate study on honey bees (A. mellifera, MRID
47267606) classified as supplemental. The study uses a formulation to
test toxicity. For honeybee acute contact toxicity studies, a TGAI test
compound is required. Relative to a similar honeybee acute contact
toxicity test (MRID 47267508), which shows no mortality at the treatment
level (100 g a.i./bee), this formulation appears to be more toxic at
a lower nominal concentration (100 g product./bee ≈ 24 g
a.i./bee) having 24% mortality. This information suggests that there is
something in the formulation that is more toxic than the active
ingredient acting alone. Finally, the concentrations of test substance
in the dosing solutions were not determined. Therefore, the actual dose
levels used are unknown.

The contact test had 2% mortality in the negative and solvent controls
and 24% mortality in the 100 µg a.i./bee level by 48 hours; sub-lethal
effects were 0% in the negative and solvent controls, and 10% in the 100
µg a.i./bee level only at 4 hours but not thereafter. The oral test
also had 2% mortality in the negative control, 0% mortality in the
solvent control, and 4% mortality in the 113.4 µg a.i./bee level by 48
hours; sub-lethal effects were 0% in the negative control, 2% in the
solvent control, and 0% in the 113.4 µg a.i./bee level.

In a 14 day acute limit toxicity study, earthworms (E. fetida, MRID
47267608) were exposed to AC 375839 300 g/L SC RLF12359 (SF10358) at
1000 mg formulation/kg dry weight of artificial soil. No concurrent
reference chemical test was conducted in this study. The report
indicated that the experiment was carried out in accordance with OECD
207. However, only one concentration was tested which did not fulfill
the requirement of the guideline. No earthworm mortality was observed in
the water control or in test substance treatment. The 14 day LC50 was >
1000 mg formulation/kg dry soil. No significant difference in earthworm
burrowing time (i.e., time needed for 10 earthworms to burrow into the
soil after placement on soil surface) was observed at day 7. The average
weight loss between Day 0 and Day 14 was 20.6 and 87.9 mg in the test
groups of water control and test substance treatment, respectively. The
difference is statistically significant. The 14 day NOEC, based on body
weight loss, was < 1000 mg/kg dry soil, the concentration tested. The
end-point toxicity concentration of the test substance can not be
determined from this study; however, it is considered to be non-lethal
to earthworms up to a concentration of 1000 mg formulation/kg dry soil.
No other observable compound related toxicity effect was reported.

Table 26.  Terrestrial Invertebrate Acute/Subacute Toxicity Data

Common Name	%AI	Study parameters	LD50 /NOAEL	MRID
Classification/Category

Technical AC 375839 (a.k.a. BAS 560F)

Honey bees

Apis

Mellifera	95.86	48 hour acute contact and oral toxicity tests

5 reps. / 10 bees per rep.

 μg a.i./bee; Oral: 0 (negative, solvent), 114 μg a.i./bee	48 hour
contact LD50 > 100 g ai/bee

NOAEC: 100 μg a.i./bee

LOAEC > 100 µg a.i./bee

48 hour oral LC50 > 114 g ai/bee

NOAEC: 114 μg a.i./bee

LOAEC > 114 µg a.i./bee 	47267508	Acceptable/ Practically non-toxic1

Earthworm Eisenia fetida	95.86	14 day acute limit toxicity

4 reps (treatment); 1 rep (control) / 10 earthworms per rep.

Nominal: 1,000 mg a.i./kg dry soil	14 day LC50 >1,000 mg a.i./kg dry
soil

NOAEC < 1,000 mg a.i./kg dry soil

LOAEC = 1,000 mg a.i./kg dry soil

Endpoint(s) affected: possibly weight loss	47267518	Supplemental/
Non-GLN2

Metabolites

Earthworm Eisenia fetida	97	CL 377160 (hydrolytic metabolite of
metrafenone)

14 day acute toxicity

4 reps (treatment); 1 rep (control) / 10 earthworms per rep.

Nominal: 198, 296, 444, 667, and 1000 mg CL 377160/kg dry soil
     	14-day LC50 >1,000 mg CL377160/kg dry soil

NOAEC: 1,000 mg CL 377160/kg dry soil

LOAEC: 1,000 mg CL 377160/kg dry soil

Endpoint(s) affected: none.	47267519	Supplemental/ Non-GLN2

Formulations

Honey bees

Apis mellifera	24.4% a.i.;

288 g/L	AC 375839 in a 300 g/L SC (SF10358/ RLF12359)

48 hour acute contact and oral toxicity tests

5 reps. / 10 bees per rep.

negative, solvent), 100 μg test material3/bee; Oral: 0 (negative,
solvent), 113.4 μg test material/bee	48 hour contact LD50 > 100 g
form/bee [>24.4 μg a.i./bee]

NOAEC < 100 μg form/bee [<24.4 μg a.i./bee]

LOAEC: 100 µg form/bee [24.4 μg a.i./bee]

48 hour oral LC50 > 113.4 g form/bee [>27.7 μg a.i./bee]

NOAEC: 113.4 μg form/bee [27.7 μg a.i./bee]

LOAEC > 113.4 µg form/bee [> 27.7 μg a.i./bee]	47267606	Supplemental/
Practically non-toxic1

Earthworm Eisenia fetida	288 g a.i./L	AC 375839 300 g/L SC RLF12359
(SF10358)

14 day acute limit toxicity

4 reps (treatment); 1 rep (control) / 10 earthworms per rep.

Nominal: 1,000 mg form/kg dry soil	14 day LC50 >1,000 mg form4/kg dry
soil

NOAEC < 1,000 mg form/kg dry soil

LOAEC < 1,000 mg form/kg dry soil

g a.i./bee) <2 highly toxic; 2-10.99 moderately toxic; ≥11
practically non-toxic

2 Deemed acceptable by PMRA

3 ‘Test material’ is assumed to mean ‘formulation’

4 Not enough information provided in the study to determine active
ingredient content

(2) Chronic Effects

Birds - Technical

≥1320 mg a.i./kg diet.

The one-generation reproductive toxicity study (MRID 47267507) used 16
pairs per level of ca. 5-month old mallard duck (Anas platyrhynchos)
over 22 weeks.  BAS 560 F was administered to the birds in the diet at
nominal concentrations of 0 (control), 450, 900, or 1350 mg ai/kg diet.
Mean-measured concentrations were <18.6 (<LOQ, control), 438, 848, and
1316 mg ai/kg diet, respectively.  No treatment-related effects were
observed on any adult parameter at any treatment level, or on any
offspring parameter at the 438 and 848 mg ai/kg diet levels.  At the
1316 mg ai/kg diet level, a statistically-significant reduction in the
number of eggs laid per hen per week was observed compared to the
control (3.3 versus 4.5 eggs/hen/week).  Hatchability was also reduced
at the 1316 mg ai/kg level, where the percentage of chicks
“dead-in-shell” of fertile eggs increased from 15.7% for the control
level to 36.8% for the 1316 mg ai/kg diet level.  As a direct result,
the percentage of hatched chicks of fertile eggs was also
statistically-different from the control (57.0 versus 77.0%).  The study
was deemed supplemental on account of several guideline deviations
including lack of reporting for pre-test mortality, the initial age of
the birds was below (ca. 5 months) recommended age (at least 7 months),
and cage size was significantly smaller than recommended (OPPTS
recommends at least 10,000 cm2 per bird; instead, the floor space was
only 4225 cm2 per bird).

Table 27.  Avian Chronic Toxicity Data

Common Name	%AI	Study Parameters	NOAEC/LOAEC	MRID	Classification

Technical AC 375839 (a.k.a. BAS 560F)

Northern Bobwhite Quail

Colinus virginianus	95.86	1-generation reproduction study

Pre-laying exposure 10 weeks; egg laying exposure 12 weeks

2 birds per pen (1 ♂: 1♀); 20 pens per neg. control and treatment

Mean measured:  <3.75 (neg. control), 181, 486, and 1320 mg a.i./kg diet
NOAEC ≥ 1320 mg a.i./kg diet

LOAEC ≥ 1320 mg a.i./kg diet

Endpoint(s) affected: none.	47267506	Acceptable

Mallard Duck

Anas platyrhynchos	99.4	1-generation reproduction study

Pre-laying exposure 10 weeks; egg laying exposure 12 weeks

2 birds per pen (1 ♂: 1♀); 20 pens per neg. control and treatment

Mean measured:  <18.6 (neg. control), 438, 848, and 1316 mg a.i./kg diet
NOAEC: = 848 mg a.i./kg diet1

LOAEC: 1316 mg a.i./kg diet

Endpoint(s) affected: egg production (eggs laid per ♀ per wk) and
hatchability (% dead-in-shell of fertile eggs)	47267507	Supplemental

1 Bold value is the value that will be used to calculate risk quotients

Mammals - Technical

In a rat 2-generation reproduction study (MRIDs 46415729, 46415728) and
given the parental animals, no treatment-related effects were observed
on mortality, clinical signs of toxicity, or macroscopic examinations.
The LOAEL for parental toxicity is 1000 ppm (equivalent to 72.8/84.8
mg/kg bw/day [M/F]), based on decreased body weights and body weight
gains in the F1 males.  The NOAEL is 500 ppm (equivalent to 35.9/42.9
mg/kg bw/day [M/F]). In the offspring, no effects of treatment were
observed on clinical signs of toxicity, litter parameters, sexual
maturation, anogenital distance, hematology, or macroscopic or
microscopic pathology. The LOAEL for offspring toxicity is 10,000 ppm
(equivalent to 759/864 mg/kg bw/day [M/F]), based on decreased body
weights in the F1 and F2 pups.  The NOAEL is 1000 ppm (equivalent to
72.8/84.8 mg/kg bw/day [M/F]). No effects of treatment were observed on
estrous cycle number or length, sperm parameters, primordial follicle
count, or reproductive performance. Thus, the LOAEL for reproductive
performance was not observed.  The NOAEL for reproductive performance is
10,000 ppm (equivalent to 759/864 mg/kg bw/day [M/F]).

In a rat developmental toxicity study (MRID 46415726), no
treatment-related effects were observed on mortalities, clinical signs,
body weights, body weight gains, food consumption, hematology, liver
weights, liver histology, or gross pathology relative to maternal
toxicity. Therefore, the maternal LOAEL was not observed.  The maternal
NOAEL is 1000 mg/kg/day (limit dose). Regarding developmental toxicity:
there were no treatment-related effects on the numbers of litters,
fetuses (live or dead), resorptions (early, late, or complete litter) or
on sex ratio or post-implantation loss, on fetal body weights or on
skeletal ossification, indicating no effect on fetal growth or
development; there were no treatment-related external, visceral, or
skeletal variations on development or other malformations. Thus, the
developmental LOAEL was not observed.  The developmental NOAEL is 1000
mg/kg/day (limit dose).

In a rabbit developmental toxicity study (MRID 46415727), no
treatment-related effect was observed on mortalities, hematology, or
gross pathology relative to maternal toxicity. Therefore, the maternal
LOAEL is 350 mg/kg/day, based on decreased body weight gains and food
consumption; increased liver weights; and increased incidences and/or
severity of periportal hepatocellular hypertrophy and diffuse
hepatocellular vacuolation.  The maternal NOAEL is 50 mg/kg/day.
Regarding developmental toxicity: there were no treatment-related
effects on the numbers of litters, fetuses (live or dead), resorptions
(early, late, or complete litter) or on sex ratio or post-implantation
loss, on fetal body weights or on skeletal ossification, indicating no
effect on fetal growth or development; there were no treatment-related
external, visceral, or skeletal variations on development or other
malformations. Thus, the developmental LOAEL was not observed.  The
developmental NOAEL is 700 mg/kg/day.

Table 28.  Mammalian Chronic Toxicity Data

Common Name	%AI	Study Parameters	NOAEC/

LOAEC	MRID	Classification/Category

Technical AC 375839 (a.k.a. BAS 560F)

Rat	95.86	2-generation reproduction study 30 CD Sprague-Dawley
rats/sex/group/generation, by feeding (diet).

3 treatment groups; 1 untreated diet control group

Nominal: 0, 5001, 1000, 10000 ppm

M: 0, 35.9, 72.8, 759 mg BAS 560 F/kg/day

F: 0, 42.9, 84.8, 864 mg BAS 560 F/kg/day

	Parental systemic NOAEL (M/F): 35.9/42.9 mg/kg bw/day1

LOAEL (M/F): 72.8/84.8 mg/kg bw/day, based on decreased body wts and
body wt gain F1 males as well as body wts in F1 and F2 females

Offspring/Develop-mental Toxicity NOAEL (M/F): 72.8/84.8 mg/kg bw/day

LOAEL (M/F): 759/864 mg/kg bw/day, based on decreased body wts in F1 and
F2 pups

Reproductive Toxicity NOAEL (M/F): 759/864 mg/kg bw/day

LOAEL (M/F):  not attained	46415729

46415728	Acceptable / Guideline

Rat	95.86	Developmental toxicity study

25 rats per dose, by gavage.

3 treatment groups; 1 untreated control group

0, 50, 500, 1000 mg BAS 560 F/kg/day	Maternal

NOAEL: 1000 mg/kg/day (HDT; limit dose)

LOAEL: not attained

Developmental

NOAEL: 1000 mg/kg/day (HDT; limit dose)

LOAEL: not attained	46415726	Acceptable/ Guideline

Rabbit	95.86	Developmental toxicity study

25 rabbits per group, by gavage.

3 treatment groups; 1 untreated control group

0, 50, 350, 700 mg BAS 560 F/kg/day	Maternal

NOAEL: 50 mg/kg/day

LOAEL: 350 mg/kg/day, based on decreased body wt gains and food
consumption; increased liver wts; increased incidences and/or severity
of periportal hepatocellular hypertrophy and diffuse hepatocellular
vacuolation

Developmental

NOAEL: 700 mg/kg/day (HDT)

LOAEL: not attained	46415727	Acceptable/ Guideline

1 Bold value is the value that will be used to calculate risk quotients

b. Terrestrial Plants

The two tier I terrestrial plant studies, seedling emergence (MRID
47267509) and vegetative vigor (MRID 47267510), are both supplemental
and are based on the UK/EU formulation (BAS 560 00F, 42.8% purity). The
lower application rates in the studies (0.091 and 0.288 lbs a.i./A for
the seedling emergence study; and, 0.091 and 0.285 lbs a.i./A for all
but soybean [0.099 and 0.283 lbs a.i./A] for the vegetative vigor study)
relative to the label application rate (0.3 lbs a.i./A) leads to
uncertainty in the risk characterization especially as effects were
noted, but the NOAEC and EC05 are undefined. The latter two endpoints
are used for endangered species risk calculations, which cannot be done
in this case. Tier II tests are requested to define the latter
endpoints, to have a study available that is based on the U.S.
formulation, and, subsequently, reduce uncertainty in risk
characterization.

All species were not significantly affected by the two treatments in the
seedling emergence study.  The most sensitive monocot and dicot species
could not be determined.  The NOAEC for all species (monocot and dicot)
was 0.288 lbs ai/A. The EC05, EC25 >0.288 lbs a.i./A. For the highest
treatment level tested, the following effects were noted -- the %
inhibition relative to control that is greater than 5% was observed in
the following plants for the given endpoint: emergence (oat, tomato);
survival (oat, onion, tomato), dry weight (onion, ryegrass), and height
(cucumber, onion, soybean, tomato).

All species were not significantly affected by the two treatments in the
vegetative vigor study.  The most sensitive monocot and dicot species
could not be determined.  The NOAEC for all monocot species was 0.285
lbs ai/A. The EC05, EC25 >0.285 lbs a.i./A. The NOAEC for all dicot
species was the same as that for the monocots except for the soybean
which was 0.283 lbs a.i./A (with the EC05 and EC25 > 0.283 lbs a.i./A).
For the highest treatment level tested, the following effects were noted
-- the % inhibition relative to control that is greater than 5% was
observed in the following plants for the given endpoint: dry weight
(ryegrass) and height (none).

Risk Characterization

Risk Estimation –Integration of Exposure and Effects Data

A quantitative estimation of risk integrates EECs and toxicity estimates
and evaluates the likelihood of adverse ecological effects to non-target
species. In a deterministic approach, an exposure estimate is divided by
a single point estimate of toxicity to calculate a risk quotient (RQ).
The RQ is then compared to Agency Levels of Concern (LOCs, Appendix H),
which serve as criteria for categorizing potential risk to non-target
organisms and the need to consider regulatory action.

Risk to Aquatic Animals and Plants

The greatest amount of uncertainty in the assessment stems from aquatic
studies which were largely based on total concentrations (both dissolved
and undissolved) of the test compound. In all cases (except for the
chronic study on the saltwater mysid, but including aquatic plants), the
risk quotient values were not calculated.

Aquatic Animals

Risk following acute exposure

Freshwater Fish and Aquatic-Phase Amphibians

The acute aquatic risk quotients (RQs) for freshwater fish and
aquatic-phase amphibians were not calculated. Test compound in solution
was not centrifuged and measured (post-centrifugation) in any of the
acute freshwater fish studies (on the technical, metabolites, and
formulations), even though higher concentrations tested exceeded or
likely exceeded the solubility limit of the test compound.  Without
centrifugation, the amount of chemical that is freely dissolved and
bioavailable cannot be determined.  Uncertainty in the level of
dissolved test compound in the solution for all studies renders
calculated endpoints suitable for qualitative use only.

Freshwater Invertebrates

The acute aquatic risk quotients (RQs) for freshwater invertebrates were
not calculated. Test compound in solution was not centrifuged and
measured (post-centrifugation) in any of the acute freshwater
invertebrate studies (on the technical, metabolites, and formulations),
even though higher concentrations tested exceeded or likely exceeded the
solubility limit of the test compound. Without centrifugation, the
amount of chemical that is freely dissolved and bioavailable cannot be
determined. Uncertainty in the level of dissolved test compound in the
solution for all studies renders calculated endpoints suitable for
qualitative use only.

Marine/Estuarine Fish

The study on the technical active ingredient (MRID 47267446) yielded an
LC50 greater than the highest concentration tested because there were no
mortalities and no sublethal effects; therefore, RQs are not reported.

Marine/Estuarine Invertebrates

The acute aquatic risk quotients (RQs) for marine/estuarine
invertebrates were not calculated. Test compound in solution was not
consistently centrifuged and measured (post-centrifugation) in any of
the acute marine/estuarine invertebrate studies (on the technical), even
though higher concentrations tested exceeded or likely exceeded the
solubility limit of the test compound.  Without centrifugation, the
amount of chemical that is freely dissolved and bioavailable cannot be
determined.  Uncertainty in the level of dissolved test compound in the
solution for all studies renders calculated endpoints suitable for
qualitative use only.

Risk following chronic exposure

Freshwater Fish and Aquatic-Phase Amphibians

The chronic aquatic risk quotients (RQs) for freshwater fish and
aquatic-phase amphibians were not calculated. Test compound in solution
was not centrifuged and measured (post-centrifugation) in the chronic
freshwater fish study (on the technical), even though higher
concentrations tested exceeded or likely exceeded the solubility limit
of the test compound. Without centrifugation, the amount of chemical
that is freely dissolved and bioavailable cannot be determined.
Uncertainty in the level of dissolved test compound in the solution for
this study renders calculated endpoints suitable for qualitative use
only.

Freshwater Invertebrates

No acceptable guideline and non-guideline chronic studies on freshwater
invertebrates are available.  Therefore, a quantitative estimation of
risk cannot be conducted.  Chronic risk to freshwater invertebrates
cannot be precluded.

Marine/Estuarine Fish

No chronic studies on marine/estuarine fish are available.  Therefore, a
quantitative estimation of risk cannot be conducted.   Chronic risk to
marine/estuarine fish cannot be precluded.

Marine/Estuarine Invertebrates

The chronic aquatic LOC was not exceeded for the proposed use of
metrafenone for the technical tested. Table 29 summarizes the RQ values
and scenarios used to compare to chronic aquatic LOCs for marine
invertebrates.

Table 29.  Metrafenone: Chronic Risks to Marine/Estuarine Invertebrates
(Application Rate 0.3 lbs a.i./A, 6 Applications/Year)

Species

 Toxicity Endpoint (µg/L)

Scenario

21-Day EEC

(µg/L)

Chronic Risk Quotient1

Levels of Concern Exceeded2

Saltwater mysid

Americamysis bahia

NOAEC = 22

g a.i./L

Technical	Grapes (Metrafenone)

NY Grapes

CA Grapes

8.82

1.10

0.40

0.05

No

No

Saltwater mysid

Americamysis bahia

NOAEC = 22

g a.i./L

Technical	Grapes (Total Metrafenone Residues)

NY Grapes

CA Grapes

17.67

1.89

0.80

0.09

No

No

1 Chronic Risk Quotients are calculated using the following formula:
EEC/NOAEC

2 Chronic LOC for marine/estuarine invertebrates = 1

Aquatic Plants

The aquatic plant risk quotients (RQs) were not calculated. Test
compound in solution was not centrifuged and measured
(post-centrifugation) in these studies (on the technical, metabolites,
and formulations), even though higher concentrations tested exceeded or
likely exceeded the solubility limit of the test compound. Without
centrifugation, the amount of chemical that is freely dissolved and
bioavailable cannot be determined.  Uncertainty in the level of
dissolved test compound in the solution for these studies renders
calculated endpoints suitable for qualitative use only.

Risk to Terrestrial Animals and Plants

Terrestrial Animals

To assess risks of metrafenone to non-target birds and mammals, EECs and
acute and chronic RQs for residues on various forage categories (short
grass, tall grass, broadleaf plants/small insects, fruits/pods/large
insects, and seeds) were obtained from the Tier 1 model, T-REX v. 1.4.1
for foliar spray applications to the proposed crops.  The model assumes
initial concentrations on plant surfaces based on Kenaga predicted
maximum residues as modified by Fletcher et al. (1994), and assumes
first-order dissipation.  In this case, six applications at 0.3 lbs
a.i./A were used.

For birds, acute RQs are derived using dose-based and dietary-based
acute toxicity values.  For mammals, acute RQs are derived using a
dose-based acute toxicity value, and chronic RQs are derived using a
dose-based chronic toxicity value (the test material was administered by
gavage) and a dietary-based chronic toxicity value using the standard
FDA laboratory rat conversion value provided in the T-REX model.
Dietary-based RQs are calculated using EECs expressed in terms of
residue concentration for the various forage categories and toxicity
values (LC50 or NOAEC) expressed in units of dietary concentration.
Dose-based RQs are calculated using a body weight-adjusted LD50 and
consumption-weighted equivalent dose sorted by food source and body
size.  For both birds and mammals, three weight categories (or sizes)
are considered.

Risk following acute exposure

Birds

The acute oral and dietary endpoints are both greater than the highest
concentrations tested (>2025 mg a.i./kg bw and >6070 mg a.i./kg diet,
respectively). There were no mortalities or treatment related clinical
signs of toxicity in the acute oral studies; one death in each dietary
study was observed but was not considered treatment related. Therefore,
RQ values are not reported. Further discussion will be provided in the
risk description.

Potential risk to piscivorous birds

The potential risk to piscivorous birds considers exposure via
consumption of fish contaminated with metrafenone total residues.
However, the acute oral and dietary endpoints are both greater than the
highest concentrations tested (>2025 mg a.i./kg bw and >6070 mg a.i./kg
diet, respectively). There were no mortalities or treatment related
clinical signs of toxicity in the acute oral studies; one death in each
dietary study was observed but was not considered treatment related.
Therefore, RQ values are not reported. Further discussion will be
provided in the risk description.

Mammals

The acute endpoints for mammals are both greater than the highest
concentrations tested (LD50: >2000 mg technical/kg bw, mouse; >5000 mg
form/kg bw, rat). There were no mortalities or treatment related
clinical signs of toxicity in the acute oral rat study; one death was
observed in the acute oral mouse study. Therefore, RQ values are not
reported. Further discussion will be provided in the risk description.

Potential risk to piscivorous mammals

The potential risk to piscivorous mammals considers exposure via
consumption of fish contaminated with metrafenone total residues.
However, the mammalian acute endpoints are both greater than the highest
concentrations tested (LD50: >2000 mg technical/kg bw, mouse; >5000 mg
form/kg bw, rat). A male mouse died in the acute oral mouse study (MRID
47267522) on the technical; there were no mortalities in the acute oral
rat study (MRID 47267609) on the formulation. Therefore, RQ values are
not reported. Further discussion will be provided in the risk
description.

Terrestrial invertebrates

Metrafenone is classified as ‘practically non-toxic’ to honey bees
on an acute contact basis, based on available data for the TGAI and
formulation (24.4% a.i.). Given a non-guideline acute earthworm study
using the technical active ingredient, metrafenone is considered to be
non-lethal to earthworms up to a concentration of 1000 mg a.i./kg dry
soil. Similarly, given a non-guideline acute earthworm study using a
metrafenone metabolite, the metabolite too is considered to be
non-lethal to earthworms up to a concentration of 1000 mg/kg dry weight
of soil. In addition, given a non-guideline acute earthworm study using
a formulation, the formulation is also considered to be non-lethal to
earthworms up to a concentration of 1000 mg formulation/kg dry soil.
Additional discussion is provided in the risk description section.

Risk following chronic exposure

Birds

Utilizing the chronic endpoint (848 mg a.i./kg diet) from a 1-generation
reproduction study (MRID 47267507) conducted with mallard duck and the
T-REX model v.1.4.1, the chronic avian dietary-based RQs do not exceeded
the chronic LOC for birds for any food category.

Table 30.  Upper Bound Kenaga, Chronic Avian Dietary Based Risk
Quotients

Grapes: 0.3 lbs a.i./A; 6 Applications/season

NOAEC (ppm)	EECs and RQs1,2,3

	Short Grass	Tall Grass	Broadleaf Plants/

Small Insects	Fruits/Pods/

Seeds/

Large Insects

	EEC	RQ	EEC	RQ	EEC	RQ	EEC	RQ

181	241.01	0.28	110.46	0.13	135.57	0.16	15.06	0.02

1 Risk Quotients are calculated using the following formula: EEC / NOAEC

2 Chronic risk LOC = 1

3 Based on avian chronic NOAEC = 848 mg a.i./kg diet

	Potential risk to piscivorous birds

The potential risk to piscivorous birds considers exposure via
consumption of fish contaminated with metrafenone total residues.  None
of the RQs exceed the chronic LOC for birds.  The following table
provides estimated RQs from KABAM using the maximum application rate and
the scenario yielding the highest aquatic EECs (New York Grapes
scenario; metrafenone total residue and high runoff scenario).

Table 31. Chronic RQ values for Birds Consuming Fish Contaminated by
Metrafenone (based on KABAM)1

Wildlife Species	Dose Based	Dietary Based2,3

sandpipers	N/A	0.016

cranes	N/A	0.016

rails	N/A	0.018

herons	N/A	0.019

small osprey	N/A	0.022

white pelican	N/A	0.023

N/A = Not applicable

1 NY Grapes scenario (at 0.3 lbs a.i./A with 6 applications/year)

2 Based on avian chronic NOAEC = 848 mg a.i./kg diet

3 LOC for chronic risk = 1.0

Mammals

The chronic LOC is exceeded on a dose basis for mammals in all size
classes eating short grass, for the 15 and 35 gram size classes eating
tall grass and broadleaf plants / small insects.  The chronic LOC on a
dietary basis is not exceeded for any of the food categories.  Risks to
mammals following chronic exposure will be further discussed in the risk
description section.

Table 32.  Upper Bound Kenaga, Chronic Mammalian Dietary Based Risk
Quotients Grapes: 0.3 lbs a.i./A; 6 Applications/season

NOAEC (ppm)	EECs and RQs1,2, 3

	Short Grass	Tall Grass	Broadleaf Plants/

Small Insects	Fruits/Pods/

Seeds/

Large Insects

	EEC	RQ	EEC	RQ	EEC	RQ	EEC	RQ

500	241.01	0.48	110.46	0.22	135.57	0.27	15.06	0.03

1 Risk Quotients are calculated using the following formula: EEC / NOAEC

2 Chronic risk LOC = 1

3 Based on mammalian chronic dietary NOAEL: 500 mg/kg diet

Table 33.  Upper Bound Kenaga, Chronic Mammalian Dose-Based Risk
Quotients

Size Class

(grams)	Adjusted NOAEL	EECs and RQs1,2, 3

Short Grass	Tall Grass	Broadleaf Plants/

Small Insects	Fruits/Pods/

Seeds/

Large Insects	Granivore

EEC	RQ	EEC	RQ	EEC	RQ	EEC	RQ	EEC	RQ

15	78.90	229.78	2.914	105.32	1.33	129.25	1.64	14.36	0.18	3.19	0.04

35	63.84	158.81	2.49	72.79	1.14	89.33	1.40	9.93	0.16	2.21	0.03

1000	27.61	36.82	1.33	16.88	0.61	20.71	0.75	2.30	0.08	0.51	0.02

1 Risk Quotients are calculated using the following formula: EEC / NOAEC

2 Chronic risk LOC = 1

3 Based on mammalian chronic dose-based NOAEL: 35.9 mg/kg bw/day

4 Bolded values exceed LOC

Potential risk to piscivorous mammals

The potential risk to piscivorous mammals considers exposure via
consumption of fish contaminated with metrafenone total residues.  None
of the RQs exceed the chronic LOC for mammals.  The following table
provides estimated RQs from KABAM using the maximum application rate and
the scenario yielding the highest aquatic EECs (New York Grapes
scenario; metrafenone total residue and high runoff scenario).

Table 34. Chronic RQ Values for Mammals Consuming Fish Contaminated by
Metrafenone (based on KABAM) 1

Wildlife Species	Dose Based2,3	Dietary Based2,3

fog/water shrew	0.103	0.019

rice rat/star-nosed mole	0.125	0.018

small mink	0.159	0.025

large mink	0.176	0.025

small river otter	0.189	0.025

large river otter	0.219	0.027

1 NY Grapes scenario (at 0.3 lbs a.i./A with 6 applications/year)

2 Based on mammalian chronic NOAEC = 35.9 mg/kg bw/day

3 LOC for chronic risk = 1.0

Terrestrial Plants

Terrestrial plant risk quotients were not calculated on account of
indeterminate endpoints generated in both the seedling emergence and
vegetative vigor studies.

Risk Description

Based on the available ecotoxicity data and predicted environmental
exposures, this ecological risk assessment supports the presumption of
risk to mammals following chronic exposure.

Risk to Aquatic Animals and Plants

Aquatic Animals

Risk following acute exposure

Freshwater Fish and Aquatic-Phase Amphibians

Technical

The metrafenone limit of water solubility is approximately 0.2-0.5 mg/L
at 12oC. The acute rainbow trout study (MRID 47267443) indicated only 5%
mortality at levels below (0.065 mg total a.i./L) and above (0.43 and
0.82 mg total a.i./L) the solubility limit, which implies the effect may
not be dose related; 16% of fish were lethargic and 5% exhibited dark
discoloration after 96 hours only at the highest concentration tested
(0.82 mg total a.i./L). The acute bluegill sunfish study (MRID 47267442)
indicated 15% mortality, 18% lethargic fish, and 12% virtually immobile
but respiring fish at the highest concentration tested (0.87 mg total
a.i./L) after 96 hours. Given that the test solution was not
centrifuged, the amount of actual dissolved active ingredient
potentially leading to the observed effects is unknown. Nevertheless,
given these studies and assuming that metrafenone concentrations in the
environment reach the solubility limit, the effect of the technical
grade active ingredient on freshwater fish is likely to be low. However,
according to the model estimated EECs (0.00153 - 0.02 mg/L, which
includes metrafenone and total metrafenone residue scenarios), levels of
metrafenone at the solubility limit are not expected to occur in the
environment given the proposed grape use. Therefore, acute risk to
freshwater fish and aquatic-phase amphibians is not expected as a result
of metrafenone use on grapes given the results from the studies using
technical grade active ingredient.

Metabolites/Degradates

The limits of water solubility for metabolites of metrafenone were not
reported in the available studies; exceedance of solubility limit for a
given metabolite (Reg. No. 4084564) was assumed given observed
undissolved test substance in all five treatment groups of one acute
study (MRID 47267445). The acute rainbow trout study (MRID 47267444) was
a limit test with no effects noted at 99 mg total a.i./L. Another acute
rainbow trout study (MRID 47267445) indicated 80% mortality at 20.3 mg
total a.i./L and 100% mortality at 35.2 and 58.4 mg total a.i./L;
sublethal effects were observed in the three highest concentrations:
20.3 mg total a.i./L (tottering, apathy, and distended abdomen), 35.2 mg
total a.i./L (apathy and distended abdomen), and 58.4 mg total a.i./L
(tottering and distended abdomen). Given that the test solution was not
centrifuged, the amount of actual dissolved metabolite potentially
leading to the observed effects is unknown. According to the model
estimated EECs (0.00225 - 0.02 mg/L, which includes total metrafenone
residue scenarios), levels of metrafenone metabolites at the tested
levels are not expected to occur in the environment given the proposed
grape use. Therefore, the effect of metrafenone metabolites on
freshwater fish is likely to be low.

Formulations

The metrafenone limit of water solubility is approximately 0.2-0.5 mg/L
at 12oC. The acute study (MRID 47267605) using a formulation (BAS 560
00F, SF 10358, RLF 12359) indicated no effects on rainbow trout at
concentrations above the solubility limit, from 3.0 to 23.3 mg total
a.i./L. Given that the test solution was not centrifuged, the amount of
actual dissolved active ingredient is unknown. Not unlike the conclusion
drawn for the technical active ingredient, given this study and assuming
that metrafenone concentrations in the environment reach the solubility
limit, the effect of this particular formulation on freshwater fish is
likely to be low. However, according to the model estimated EECs
(0.00153 - 0.02 mg/L, which includes metrafenone and total metrafenone
residue scenarios), levels of metrafenone at the solubility limit are
not expected to occur in the environment given the proposed grape use.
Although this EU/UK formulation closely matches the U.S. formulation
(i.e., BAS 560 03F) it is still not its equivalent. Therefore, the
effect of the U.S. formulated product on freshwater fish and
aquatic-phase amphibians is not known.

Freshwater Invertebrates

Technical

The metrafenone limit of water solubility is approximately 0.2-0.5 mg/L
at 12oC. The acute study (MRID 47267437), in which the three highest
concentrations (0.22, 0.45, and 0.92 mg total a.i./L) were at or above
the solubility limit, indicated no effects on daphnia. Given that the
test solution was not centrifuged, the amount of actual dissolved active
ingredient is unknown. Nevertheless, given this study and assuming that
metrafenone concentrations in the environment reach the solubility
limit, the effect of the technical grade active ingredient on freshwater
invertebrates is likely to be low. However, according to the model
estimated EECs (0.00153 - 0.02 mg/L, which includes metrafenone and
total metrafenone residue scenarios), levels of metrafenone at the
solubility limit are not expected to occur in the environment given the
proposed grape use. Therefore, acute risk to freshwater invertebrates is
not expected as a result of metrafenone use on grapes given the results
from the studies using technical grade active ingredient.

Metabolites/Degradates

The limits of water solubility for metabolites of metrafenone were not
reported in the available studies. The acute daphnia study (MRID
47267438) with CL 375816 indicated no effects. Another acute daphnia
study (MRID 47267439) indicated 5, 55, and 65% immobility at the three
highest concentrations 23.2, 49.6, and 66.4 mg total a.i./L,
respectively, after 48 hours (test termination). Given that the test
solution was not centrifuged, the amount of actual dissolved metabolite
potentially leading to the observed effects is unknown. According to the
model estimated EECs (0.00225 - 0.02 mg/L, which includes total
metrafenone residue scenarios), levels of metrafenone metabolites at the
tested levels are not expected to occur in the environment given the
proposed grape use. Therefore, the effect of metrafenone metabolites on
freshwater invertebrates is likely to be low.

Formulations

The metrafenone limit of water solubility is approximately 0.2-0.5 mg/L
at 12oC. The acute study (MRID 47267604) using a formulation (BAS 560
00F, SF 10358, RLF 12359) indicated 65 and 90% mortality at the two
highest concentrations 6.0 and 11.6 mg total a.i./L, respectively, at 48
hours (test termination); 5% immobility was observed in the negative
control, 0.76 and 1.5 mg total a.i./L concentrations, 15% at 3.0 mg
total a.i./L, and 25% at 6.0 mg total a.i./L. Given that the test
solution was not centrifuged, the amount of actual dissolved active
ingredient potentially leading to the observed effects is unknown. Not
unlike the conclusion drawn for the technical active ingredient, given
this study and assuming that metrafenone concentrations in the
environment reach the solubility limit, the effect of this particular
formulation on freshwater invertebrates is potentially low. However,
according to the model estimated EECs (0.00153 - 0.02 mg/L, which
includes metrafenone and total metrafenone residue scenarios), levels of
metrafenone at the solubility limit are not expected to occur in the
environment given the proposed grape use. Although this EU/UK
formulation closely matches the U.S. formulation (i.e., BAS 560 03F) it
is still not its equivalent. Therefore, the effect of the U.S.
formulated product on freshwater invertebrates is not known.

Marine/Estuarine Fish

The study on the technical active ingredient (MRID 47267446) yielded an
LC50 greater than the highest concentration tested because there were no
mortalities and no sublethal effects; therefore, RQs were not reported.
Comparison of the peak aquatic EECs (0.02 mg/L, taken from the total
metrafenone residue scenario) with the highest concentration tested
(0.65 mg a.i./L uncentrifuged; 0.35 mg a.i./L centrifuged) shows that
the EECs were at least 17 times less than the highest concentrations
tested in the studies. Therefore, acute risk to marine/estuarine fish is
not expected as a result of metrafenone use on grapes.

Marine/Estuarine Invertebrates

The metrafenone limit of water solubility is approximately 0.2-0.5 mg/L
at 12oC. The acute eastern oyster study (MRID 47267440) indicated
effects on shell deposition, whereby relative to the negative control
the mean percent reduction in shell growth starting with the negative
solvent (then, 0.0522, 0.104, 0.203, 0.287 mg total a.i./L, and 0.33 mg
dissolved a.i./L) is as follows: 17.4, 13.9, 26.3, 44.3, 84.2, and 100%,
respectively. Therefore, should concentrations in the environment reach
the solubility limit, the acute risk to marine/estuarine invertebrates
may be expected. However, given that the test solution was not
centrifuged for all but the highest test concentration, the amount of
actual dissolved active ingredient potentially leading to the observed
effects is unknown. Meaning that interpretation of effects from total
concentrations cited here may underestimate potential risk. Similarly,
the acute saltwater mysid study (MRID 47267441) indicated a dose related
effect, this time on mortality at the four out of five highest
concentrations: 5% at 0.129 and 0.240 mg total a.i./L, 15% at 0.416 mg
total a.i./L, and 95% at 0.663 mg total a.i./L; in addition, erratic
swimming was observed in the two highest concentrations by test
termination. Despite the dose response, without centrifugation, the
amount of chemical that is freely dissolved and bioavailable cannot be
determined and, again, interpretation of effects from total
concentrations cited here may underestimate potential risk. However,
according to the model estimated EECs (0.00153 - 0.02 mg/L, which
includes metrafenone and total metrafenone residue scenarios), levels of
metrafenone at the solubility limit are not expected to occur in the
environment given the proposed grape use. Given these studies and
assuming that metrafenone concentrations in the environment are not
likely to reach the solubility limit, the acute risk to marine/estuarine
invertebrates is not expected.

Risk following chronic exposure

Freshwater Fish and Aquatic-Phase Amphibians

a.i./L (p≤0.05).  Post-hatch survival averaged 96% at the negative
control through 0.118 mg total a.i./L levels, and 87, 86, and 11% at the
0.227, 0.421, and 0.839 mg total ai/L levels, respectively.  Therefore,
a dose response is evident and implies that should concentrations in the
environment reach the solubility limit, the chronic risk to freshwater
fish may be expected. No clinical signs of toxicity were observed during
the study in any treatment group.  Fish length was significantly reduced
relative to the average negative control length at the two highest
concentrations 0.421 and 0.839 mg total ai/L and wet and dry weight were
significantly lower than the negative control weights at the highest
concentration (0.839 mg total a.i./L level); however, significant impact
on survival occurred at these levels. Given that the test solution was
not centrifuged, the amount of actual dissolved active ingredient
potentially leading to the observed effects is unknown. For example, the
NOAEC value is low (0.118 mg total a.i./L) even though the measured
concentration includes dissolved and undissolved substance, but had the
sample been centrifuged – including the dissolved compound only - the
value would likely be lower. Therefore, conclusions drawn from these
data would lead to an underestimation of potential risk. According to
the model estimated EECs (0.00075 - 0.017 mg/L, which includes
metrafenone and total metrafenone residue scenarios), levels of
metrafenone at the solubility limit are not expected to occur in the
environment given the proposed grape use. Assuming that metrafenone
concentrations in the environment are not likely to reach the solubility
limit or the concentrations used in this study, the chronic risk to
freshwater fish and aquatic-phase amphibians is not expected.

Freshwater Invertebrates

No acceptable chronic ecotoxicity studies on freshwater invertebrates
are available. Chronic risk to freshwater invertebrates cannot be
precluded.

Marine/Estuarine Fish

No chronic ecotoxicity studies on estuarine/marine fish have been
submitted to the Agency for review.  Chronic risk to estuarine/marine
fish cannot be precluded.

Marine/Estuarine Invertebrates

The chronic aquatic LOC was not exceeded for the proposed use of
metrafenone for the technical active ingredient (MRID 47267448) tested
on the marine/estuarine invertebrate (saltwater mysid); no data is
available for metabolites or formulation studies on marine/estuarine
invertebrates. Although reproduction (number of offspring per female per
reproductive day) was the (most sensitive) affected endpoint in this
study, yielding a definitive endpoint, the RQ calculations indicate that
chronic risk to marine/estuarine invertebrates is not expected as a
result of metrafenone use.

Aquatic Plants

For all aquatic plant studies, dissolved or soluble concentrations
(i.e., post-centrifugation) of test material were not determined.
Without centrifugation, the amount of chemical that is freely dissolved
and bioavailable cannot be determined. This is especially a problem as
some of the testing concentrations were conducted above the solubility
limit of the technical grade active ingredient (MRID 47267511, 47267512,
47267513, 47267514, 47267515, technical; MRID 47267607, formulation). In
addition, the metabolite solubility limit is unknown which leads to
uncertainty in interpreting the measured concentrations in the
metabolite studies (MRID 47267516, 47267517).  The lowest concentration
tested among the vascular plants (MRID 47267511, L. gibba: 0.057 mg
total a.i./L; or, 0.033 mg a.i./L assuming a 42% reduction after
hypothetical centrifugation) and non-vascular plants (MRID 47267513, S.
costatum: 0.0509 mg total a.i./L; or 0.0295 mg a.i./L) is higher than
the highest peak aquatic EEC value of 0.02 mg/L (assuming the total
metrafenone residue scenario). Therefore, had valid endpoints (i.e.,
those based on dissolved concentrations) been determined using these
studies, they would likely be greater than the highest model predicted
concentration in the environment, which implies that risk to vascular
and non-vascular species is not expected as a result of metrafenone use
on grapes. Although the EU/UK formulation used in one of the studies
closely matches the U.S. formulation (i.e., BAS 560 03F) it is still not
its equivalent. Therefore, the effect of the U.S. formulated product on
vascular and non-vascular aquatic plants is not known.

Risk to Terrestrial Animals and Plants

Terrestrial Animals

Risk following acute exposure

Birds

The acute oral and dietary endpoints are both greater than the highest
concentrations tested (>2025 mg a.i./kg bw and >6070 mg a.i./kg diet,
respectively). There were no mortalities or treatment related clinical
signs of toxicity in the acute oral studies; one death in each dietary
study was observed but was not considered treatment related. As a
result, RQ values were not reported. Toxicity characterization implies
that the technical is practically non-toxic. In addition, the highest
concentration tested for the oral studies (2025 mg a.i./kg bw) is 7
times higher than the highest dose-based EEC (274.49 mg/kg) calculated
from T-REX; meanwhile, the highest concentration tested for the dietary
studies (6070 mg a.i./kg diet) is 25 times higher than the highest
dietary-based EEC (241.01 mg/kg). Therefore, given that comparison,
acute risk to birds is not expected as a result of metrafenone use.

Potential risk to piscivorous birds

Several characteristics of metrafenone indicate that it has the
potential to accumulate in tissues of aquatic organisms.  The log of the
n-octanol/water partition coefficient for metrafenone is 4.3 (at 25oC,
pH 4). The lipid normalized BCF was determined to be between 140 and 530
(see MRID 47267450).

As stated in the risk estimation section, the acute oral and dietary
endpoints are both greater than the highest concentrations tested (>2025
mg a.i./kg bw and >6070 mg a.i./kg diet, respectively). There were no
mortalities or treatment related clinical signs of toxicity in the acute
oral studies; one death in each dietary study was observed but was not
considered treatment related. As a result, RQ values were not reported.
The highest concentration tested for the oral studies (2025 mg a.i./kg
bw) is 147 times higher than the highest dose-based EEC (13.73 mg/kg
bw/day) calculated from KABAM for birds consuming fish contaminated by
metrafenone total residues; meanwhile, the highest concentration tested
for the dietary studies (6070 mg a.i./kg diet) is 310 times higher than
the highest dietary-based EEC (19.59 mg/kg). Therefore, given that
comparison, acute risk to piscivorous birds is not expected due to
consumption of fish contaminated with metrafenone.

Mammals

There were no mortalities in the acute oral rat study (MRID 47267609) on
the formulation; one death was observed in the acute oral mouse study
(MRID 47267522) on the technical active ingredient.  Although the EU/UK
formulation used in the formulation study closely matches the U.S.
formulation (i.e., BAS 560 03F) it is still not its equivalent.
Therefore, the effect of the U.S. formulated product on mammals is not
known.

The acute endpoints for mammals are both greater than the highest
concentrations tested (LD50: >2000 mg technical/kg bw, mouse; >5000 mg
form/kg bw, rat). Therefore, RQ values were not reported. In the mouse
study, only 3 individuals/sex were tested with mortality in 1/6 animals
(17%).  With a larger test sample, the LD50 could be approached. The
toxicity classification implies that the technical is practically
non-toxic to mice. In addition, the highest concentration tested for the
oral study (2000 mg a.i./kg bw) is 9 times higher than the highest
dose-based EEC (229.78 mg/kg) calculated from T-REX. Therefore, given
that comparison, acute risk to mammals is not expected as a result of
metrafenone use.

Potential risk to piscivorous mammals

Risk to piscivorous mammals via consumption of fish contaminated with
metrafenone was assessed because metrafenone has the potential to
accumulate in tissues of aquatic organisms.

As stated in the risk estimation section, there were no mortalities in
the acute oral rat study (MRID 47267609) on the formulation and there
was only one death in the acute oral mouse study (MRID 47267522) on the
technical. Although the EU/UK formulation used in the formulation study
matches the U.S. formulation (i.e., BAS 560 03F) it is still not its
equivalent. Therefore, the effect of the U.S. formulated product on
mammals is not known.

The highest concentration tested for the oral studies (2000 mg a.i./kg
bw) is 257 times higher than the highest dose-based EEC (7.795 mg/kg
bw/day) calculated from KABAM for mammals consuming fish contaminated by
metrafenone total residues. Therefore, given that comparison, acute risk
to piscivorous mammals is not expected due to consumption of fish
contaminated with metrafenone.

Terrestrial invertebrates

The 48-hour contact LD50 is >24.4 μg a.i./bee [>100 μg form/bee] with
a NOAEC of <24.4 μg a.i./bee and a LOAEC of 24.4 µg a.i./bee based on
mortality.  Based on this toxicity data, metrafenone is classified as
‘practically non-toxic’ to honeybees on an acute contact basis.
Thus, risk to honeybees is not expected as a result of direct contact
with metrafenone.  Similarly, the non-guideline earthworm studies
consider metrafenone, its degradate, and a formulation to be non-lethal
to earthworms up to a concentration of 1000 mg a.i./kg dry soil, 1000
mg/kg dry weight of soil, and 1000 mg formulation/kg dry soil,
respectively. E. fetida is found in topsoil at depths of approximately
5-20cm. Given a soil depth of 20 cm and assuming a maximum application
rate per season (1.8 lbs a.i./A, which assumes a hypothetical maximum
active ingredient loading rate since the seasonal rate would not be
applied all at once and likely degrade if applied in the recommended 6
applications of at most 0.3 lbs a.i./A), the EEC is much lower (0.77
mg/kg soil) than the concentrations generated in these studies. At
shallower depths (5 cm), the EEC is higher (3.08 mg/kg soil), but still
lower than the study concentration (1000 mg a.i./kg soil). Therefore,
risk to earthworms is not expected as a result of metrafenone use on
grapes. Although the EU/UK formulation used in the formulation studies
for the bee and earthworm matches the U.S. formulation (i.e., BAS 560
03F) it is still not its equivalent. Therefore, the effect of the U.S.
formulated product on bees (and earthworms) is not known.

Risk following chronic exposure

Birds

The chronic avian dietary-based RQ does not exceed the chronic LOC for
birds for any food catogory. The study (MRID 47267507) was done on
mallard duck using the technical grade and yielded a definite endpoint
based on egg production (eggs laid per female per week) and hatchability
(% dead-in-shell of fertile eggs). Due to the fact that the RQ is only
based on one bird species, there is an uncertainty associated with the
estimated risk for all avian species. Nevertheless, given that LOCs were
not exceeded, chronic risk to birds is not expected as a result of
metrafenone use on grapes.

Potential risk to piscivorous birds

As previously stated, risk to piscivorous birds via consumption of fish
contaminated with metrafenone was assessed because metrafenone has the
potential to accumulate in tissues of aquatic organisms.  As stated in
the risk estimation section, none of the RQs exceed the chronic LOC for
birds.   Therefore, chronic risk to piscivorous birds is not expected
due to consumption of fish contaminated with metrafenone total residues.

Mammals

The chronic LOC is exceeded on a dose basis for mammals in all size
classes eating short grass, for the 15 and 35 gram size classes eating
tall grass and broadleaf plants / small insects.  The chronic LOC on a
dietary basis is not exceeded for any of the food categories.  The study
(MRID 46415729, 46415728) was done on the rat using the technical grade
and yielded a definite endpoint based on decreased body weights and body
weight gain in F1 males as well as body weights in F1 and F2 females.
Due to the fact that the RQ is only based on one mammalian species,
there is an uncertainty associated with the estimated risk for all
mammals. Nevertheless, given the LOC exceedance chronic risk to mammals
is expected as a result of metrafenone use. To reduce chronic risk to
mammals, several components of the application protocol would have to
change. For example, in order to have no chronic LOC exceedances (i.e.,
all RQs < 1) for mammals, the minimum single application rate (0.2 lbs
a.i./A) would have to be cut by 25% (i.e., to 0.15 lbs a.i./A) yet
considered the maximum instead, the application interval would have to
nearly double (from 14 days up to 26 days), and the maximum allowed
number of applications would have to be cut from 6 to 5. Alternatively,
in order to have no chronic LOC exceedances for mammals, the minimum
single application rate (0.2 lbs a.i./A) can still be applied yet
considered the maximum instead, but the application interval would have
to nearly double (from 14 days up to 26 days), and the maximum number of
applications would have to be cut by 50% (i.e., from 6 to 3).
Furthermore, in order to have no chronic LOC exceedances in nearly all
cases for mammals –the one exception being an exceedance for the 15g
size glass consuming short grass where the calculated RQ is 1.02 – the
minimum single application rate (0.2 lbs a.i./A) would be changed to the
maximum single application rate and the application interval (14 days)
could remain as currently prescribed by the label, but the maximum
number of applications would have to be reduced from 6 to 2.

Potential risk to piscivorous mammals

As previously stated, risk to piscivorous mammals via consumption of
fish contaminated with metrafenone was assessed because metrafenone has
the potential to accumulate in tissues of aquatic organisms.  As stated
in the risk estimation section, none of the RQs exceed the chronic LOC
for mammals.   Therefore, chronic risk to piscivorous mammals is not
expected due to consumption of fish contaminated with metrafenone.

Terrestrial Plants

As stated in the risk estimation section, terrestrial plant risk
quotients were not calculated on account of indeterminate endpoints
generated in both the seedling emergence and vegetative vigor studies.
The lower application rates in the studies (0.091 and 0.288 lbs a.i./A
for the seedling emergence study; and, 0.091 and 0.285 lbs a.i./A for
all but soybean [0.099 and 0.283 lbs a.i./A] for the vegetative vigor
study) relative to the label application rate (0.3 lbs a.i./A) leads to
uncertainty in the risk characterization especially as effects were
noted. However, the effects in both studies are not considered
significant and the NOAEC and EC05 are undefined (seedling emergence:
NOAEC 0.288 lbs a.i./A; EC05, EC25 > 0.288 lbs a.i./A; vegetative vigor:
NOAEC 0.285 lbs a.i./A; EC05, EC25 > 0.285 lbs a.i./A). Consequently,
the most sensitive monocot and dicot species could not be determined
from either study. Hypothetically, had the NOAEC been determined to be
0.091 lbs a.i./A (the lower concentration tested) in both the vegetative
vigor and seedling emergence studies and given the maximum single
application rate (0.3 lbs a.i./A), the risk would not have triggered
concern for either the dicot or monocot species. In addition, the EECs
based on the maximum seasonal application rate (1.8 lbs a.i./A) range
from 0.018 – 0.198 lbs a.i./A, which are below the concentrations
tested in these studies. Since effects were not significant at the test
concentrations, which are higher than the calculated EECs, risk to
terrestrial plants is not expected as a result of use of the EU/UK
formulation. Both studies were conducted on the EU/UK formulation (BAS
560 00F); therefore, uncertainty exists in determining risk to the U.S.
formulation (BAS 560 03F). Tier II tests are requested to better define
the toxicity endpoints, to have a study available that is based on the
U.S. formulation, and, subsequently, reduce uncertainty in risk
characterization.

Review of Incident Data

With the proposed use on grapes, metrafenone will be applied in the
United States for the first time.  Therefore, no incident data are
available at this time.

Endocrine Effects

As required under FFDCA section 408(p), EPA has developed the Endocrine
Disruptor Screening Program (EDSP) to determine whether certain
substances (including pesticide active and other ingredients) may have
an effect in humans or wildlife similar to an effect produced by a
“naturally occurring estrogen, or other such endocrine effects as the
Administrator may designate.”  The EDSP employs a two-tiered approach
to making the statutorily required determinations. Tier 1 consists of a
battery of 11 screening assays to identify the potential of a chemical
substance to interact with the estrogen, androgen, or thyroid (E, A, or
T) hormonal systems.  Chemicals that go through Tier 1 screening and are
found to have the potential to interact with E, A, or T hormonal systems
will proceed to the next stage of the EDSP where EPA will determine
which, if any, of the Tier 2 tests are necessary based on the available
data. Tier 2 testing is designed to identify any adverse endocrine
related effects caused by the substance, and establish a dose-response
relationship between the dose and the E, A, or T effect.

Between October 2009 and February 2010, EPA is issuing test orders/data
call-ins for the first group of 67 chemicals, which contains 58
pesticide active ingredients and 9 inert ingredients.  This list of
chemicals was selected based on the potential for human exposure through
pathways such as food and water, residential activity, and certain
post-application agricultural scenarios.  This list should not be
construed as a list of known or likely endocrine disruptors.

Metrafenone is not among the group of 58 pesticide active ingredients on
the initial list to be screened under the EDSP.  Under FFDCA sec. 408(p)
the Agency must screen all pesticide chemicals.  Accordingly, EPA
anticipates issuing future EDSP test orders/data call-ins for all
pesticide active ingredients.

For further information on the status of the EDSP, the policies and
procedures, the list of 67 chemicals, the test guidelines and the Tier 1
screening battery, please visit our website:  http://www.epa.gov/endo/.

Federally Threatened and Endangered (Listed) Species

Section 7 of the Endangered Species Act, 16 U.S.C. Section 1536(a)(2),
requires all federal agencies to consult with the National Marine
Fisheries Service (NMFS) for marine and anadromous listed species, or
the United States Fish and Wildlife Services (FWS) for listed wildlife
and freshwater organisms, if they are proposing an "action" that may
affect listed species or their designated habitat.  Each federal agency
is required under the Act to insure that any action they authorize,
fund, or carry out is not likely to jeopardize the continued existence
of a listed species or result in the destruction or adverse modification
of designated critical habitat.  To jeopardize the continued existence
of a listed species means "to engage in an action that reasonably would
be expected, directly or indirectly, to reduce appreciably the
likelihood of both the survival and recovery of a listed species in the
wild by reducing the reproduction, numbers, or distribution of the
species" (50 C.F.R. § 402.02).

To facilitate compliance with the requirements of the Endangered Species
Act (subsection (a)(2)), the Office of Pesticide Programs has
established procedures to evaluate whether a proposed registration
action may directly or indirectly reduce appreciably the likelihood of
both the survival and recovery of a listed species in the wild by
reducing the reproduction, numbers, or distribution of any listed
species (USEPA, 2004).  After the Agency’s screening level risk
assessment is conducted, if any of the Agency’s listed species LOCs
are exceeded for either direct or indirect effects, an analysis is
conducted to determine if any listed or candidate species may co-occur
in the area of the proposed pesticide use or areas downstream or
downwind that could be contaminated from drift or runoff/erosion.  If
listed or candidate species may be present in the proposed action areas,
further biological assessment is undertaken.  The extent to which listed
species may be at risk then determines the need for the development of a
more comprehensive consultation package as required by the Endangered
Species Act.

Both acute endangered species and chronic risk LOCs are considered in
the screening-level risk assessment of pesticide risks to listed
species. Endangered species acute LOCs are a fraction of the
non-endangered species LOCs or, in the case of endangered plants, RQs
are derived using lower toxicity endpoints than non-endangered plants.
Therefore, concerns regarding listed species within a taxonomic group
are triggered in exposure situations where restricted use or acute risk
LOCs are triggered for the same taxonomic group.  The risk assessment
also includes an evaluation of the potential probability of individual
effects for exposures that may occur at the established endangered
species LOC both in the risk characterization and the endangered species
sections.  This probability is calculated using the established
dose/response relationship and assumes a probit (probability unit)
dose/response relationship.

Action Area

For listed species assessments, the action area is considered to be the
area affected directly or indirectly by the Federal action and not
merely the immediate area where metrafenone is applied.  At the initial
Level 1 screening assessment, broadly described taxonomic groups are
considered, and thus, conservatively assumes that listed species within
those broad groups are co-located with the pesticide treatment area.
This means that terrestrial plants and wildlife are assumed to be
located on or adjacent to the treated site and aquatic organisms are
assumed to be located in a surface water body adjacent to the treated
site.  The assessment also assumes that listed species are located
within the area of highest exposure to the pesticide, and that exposure
will decrease with increasing distance from the treated area.

If the assumptions associated with the screening-level action area
result in RQs that are below the listed species LOCs, a "no effect"
determination conclusion is made with respect to listed species in that
taxa, and no further refinement of the action area is necessary.
Furthermore, RQs below the listed species LOCs for a given taxonomic
group indicate no concern for indirect effects upon listed species that
depend upon the taxonomic group covered by the RQ as a resource.
However, in situations where the screening assumptions lead to RQs in
excess of the listed species LOCs for a given taxonomic group, a
potential for a "may affect" conclusion exists and may be associated
with direct effects on listed species belonging to that taxonomic group
or may extend to indirect effects upon listed species that depend upon
that taxonomic group as a resource.  In such cases, additional
information on the biology of listed species, the locations of these
species, and the locations of use sites could be considered along with
available information on the fate and transport properties of the
pesticide to determine the extent to which screening assumptions
regarding an action area apply to a particular listed organism.  These
subsequent refinement steps could consider how this information would
impact the action area for a particular listed organism and may
potentially include areas of exposure that are downwind and downstream
of the pesticide use site.

Taxonomic Groups Potentially at Risk

The preliminary risk assessment for endangered species indicates that
the proposed use and application rate for metrafenone either exceeds the
Endangered Species LOCs for the following taxonomic groups (underlined
[chronic exposure to mammals]) or those for which risk cannot be
precluded (also underlined [chronic exposure to freshwater fish and
invertebrates, acute exposure to marine/estuarine invertebrate, chronic
exposure to marine/estuarine fish]).

Chronic exposure to mammals

Data was not submitted or was deemed invalid for the following: chronic
exposure to freshwater invertebrates and marine/estuarine fish. A
passerine bird study is also not available at this time. Lack of data
does not preclude risk.

Data was supplemental, but inadequate for risk quotient calculations
which would have helped to determine risk to endangered species for the
following: acute exposure to freshwater fish and invertebrates, acute
exposure to marine/estuarine invertebrates, chronic exposure to
freshwater fish; and, aquatic plants. Therefore, there is uncertainty in
determining risk to these taxonomic groups. However, the total
concentration based endpoint (EC50: 0.22 mg total a.i./L) for the acute
marine/estuarine invertebrate (eastern oyster) study (MRID 47267440)
with an effect on shell deposition is 11x greater than the highest
estimated EEC (0.02 mg/L), hence risk to federally listed
marine/estuarine invertebrates cannot be precluded. The total
concentration based endpoint (NOAEC: 0.118 mg total a.i./L) for the
chronic freshwater fish (fathead minnow) study (MRID 47267449) with an
effect on post-hatch survival is approximately 7x greater than the
highest estimated EEC (0.016 mg/L), hence risk to federally listed
freshwater fish cannot be precluded. Applying similar calculations to
the acute freshwater fish and invertebrate data as well as data for
aquatic plants assumes low risk to federally listed species.

Data was acceptable, but inadequate for risk quotient calculations for
the following: acute exposure to marine/estuarine fish. Therefore, there
is uncertainty in determining risk to these taxonomic groups. The
highest concentration tested in the acute marine/estuarine fish
(sheepshead minnow) study (MRID 47267446) was 0.35 mg dissolved a.i./L
which is 17.5x greater than the highest estimated EEC (0.02 mg/L) but
there were no effects on mortality or sublethal effects, hence risk to
federally listed marine/estuarine fish is assumed to be low. Acceptable
data for acute exposure to birds yields non-definitive endpoints with no
effects; therefore, acute risk to federally listed birds is expected to
be low. For similar reasons, acute risk to federally listed piscivorous
birds, mammals, and piscivorous mammals is also expected to be low.

Concerns For Federally Listed as Endangered and/or Threatened Species

Table 35.  Listed Species Risks Associated with Direct or Indirect
Effects from Metrafenone use on Grapes at the Maximum Proposed
Application Rate (0.3 lbs a.i./A, Assuming 6 Applications/Year)  TC
"Table IB-1.  Listed species risks associated with direct or indirect
effects due to applications of propazine on sorghum" \f C \l "1"

Listed Taxon	Direct Effects	Indirect Effects

Terrestrial and semi-aquatic plants - monocots	No	Yes from effects to
mammals

Terrestrial and semi-aquatic plants – dicots	No	Yes from effects to
mammals

Terrestrial invertebrates	No	Yes from effects to mammals

Birds	No	Yes from effects to mammals, FW fish, FW inverts, M/E fish,
M/E inverts (mollusks)

Terrestrial-phase amphibians	No	Yes from effects to mammals

Reptiles	No	Yes from effects to mammals, FW fish, FW inverts, M/E fish,
M/E inverts (mollusks)

Mammals	Yes for chronic1	Yes from effects to mammals, FW fish, FW
inverts, M/E fish,  M/E inverts (mollusks)

  Aquatic non-vascular plants	No	Yes from effects to mammals, FW fish,
FW inverts, M/E fish,  M/E inverts (mollusks)

Aquatic vascular plants	No	Yes from effects to mammals, FW fish, FW
inverts, M/E fish,  M/E inverts (mollusks)

Freshwater (FW) fish	Yes for chronic2	Yes from effects to mammals, FW
fish, FW inverts, M/E fish,  M/E inverts (mollusks)

Aquatic-phase amphibians	Yes for chronic3	Yes from effects to mammals,
FW fish, FW inverts, M/E fish,  M/E inverts (mollusks)

Freshwater (FW) invertebrates	Yes for chronic4	Yes from effects to
mammals, FW fish, FW inverts, M/E fish,  M/E inverts (mollusks)

Marine/estuarine (M/E) fish	Yes for chronic4	Yes from effects to
mammals, FW fish, FW inverts, M/E fish,  M/E inverts (mollusks)

Marine/estuarine (M/E) invertebrates (mollusk)	Yes for acute5,

No for chronic6 	Yes from effects to mammals, FW fish, FW inverts, M/E
fish,  M/E inverts (mollusks)

1 The chronic LOC is exceeded on a dose basis for mammals in all size
classes eating short grass, for the 15 and 35 gram size classes eating
tall grass and broadleaf plants / small insects.  The chronic LOC on a
dietary basis is not exceeded for any of the food categories.

2 The total concentration based endpoint (NOAEC: 0.118 mg total a.i./L)
for the chronic freshwater fish (fathead minnow) study (MRID 47267449)
with an effect on post-hatch survival is approximately 7x greater than
the highest estimated EEC (0.016 mg/L), hence risk to federally listed
freshwater fish cannot be precluded.

3 Results from freshwater fish used as surrogate for assessing risk to
aquatic-phase amphibians

4 Studies not submitted or invalid for which risk cannot be precluded.

5 Mollusk (Eastern oyster); 6 Saltwater mysid

Discussion of risk quotients

The Agency’s LOCs for mammals (chronic) are exceeded for the use of
metrafenone on grapes as outlined in previous sections. The risk to the
remaining federally listed taxonomic groups (freshwater fish and
invertebrates (chronic), marine/estuarine invertebrate (acute),
marine/estuarine fish (chronic)) cannot be precluded on the basis of
toxicity data and estimated exposures. Should estimated exposure levels
occur in proximity to listed resources, the available screening level
information suggests a potential concern for direct effects on listed
species within the taxonomic groups listed above associated with the
uses of metrafenone as described in Section III.A.  The registrant must
provide information on the proximity of federally listed mammals,
freshwater fish and invertebrates, as well as marine/estuarine fish and
invertebrates to the metrafenone use sites. This requirement may be
satisfied in one of three ways: 1) having membership in the FIFRA
Endangered Species Task Force (Pesticide Registration [PR] Notice
2000-2); 2) citing FIFRA Endangered Species Task Force data; or 3)
independently producing these data, provided the information is of
sufficient quality to meet FIFRA requirements. The information will be
used by the OPP Endangered Species Protection Program to develop
recommendations to avoid adverse effects to listed species.

Probit dose response relationship

The Agency uses the probit dose response relationship as a tool for
providing additional information on the potential for acute direct
effects to aquatic and terrestrial animals (U.S. EPA, 2004).  As part of
the risk characterization, an interpretation of acute RQ for listed
species is discussed.  This interpretation is presented in terms of the
chance of an individual event (i.e., mortality or immobilization) should
exposure at the EEC actually occur for a species with sensitivity to
metrafenone on par with the acute toxicity endpoint selected for RQ
calculation.  To accomplish this interpretation, the Agency uses the
slope of the dose response relationship available from the toxicity
study used to establish the acute toxicity measures of effect for each
taxonomic group that is relevant to this assessment.  The individual
effects probability associated with the acute RQ is based on the mean
estimate of the slope and an assumption of a probit dose response
relationship.  In addition to a single effects probability estimate
based on the mean, upper and lower estimates of the effects probability
are also provided to account for variance in the slope, if available.
The upper and lower bounds of the effects probability are based on
available information on the 95% confidence interval of the slope.
Studies with good probit fit characteristics (i.e., statistically
appropriate for the data set) are associated with a high degree of
confidence.  Conversely, a low degree of confidence is associated with
data from studies that do not statistically support a probit dose
response relationship.  In addition, confidence in the data set may be
reduced by high variance in the slope (i.e., large 95% confidence
intervals), despite good probit fit characteristics.  In the event that
dose response information is not available to estimate a slope, a
default slope assumption of 4.5 (95% C.I.: 2 to 9) (Urban and Cook,
1986) is used.

Individual effect probabilities are calculated based on an Excel
spreadsheet tool IEC v1.1 (Individual Effect Chance Model Version 1.1)
developed by the U.S. EPA, OPP, Environmental Fate and Effects Division
(June 22, 2004).  The model allows for such calculations by entering the
mean slope estimate (and the 95% confidence bounds of that estimate) as
the slope parameter for the spreadsheet.  In addition, the acute RQ is
entered as the desired threshold. However, on account of either
non-definitive acute endpoints or endpoints based on total
concentrations (dissolved + undissolved test compound) instead of
dissolved concentrations only, the acute studies which would otherwise
be useful for calculating individual effect probabilities cannot be
used.

Data related to under-represented taxa

Effects data on under-represented taxonomic groups were not submitted by
the Registrant. Effects data from other analyzed sources were either not
obtained (ECOTOX Database, PAN Database) or were not available (publicly
available ECOTOX) for this screening risk assessment.

Implications of sublethal effects

For the sublethal effects discussed below, it is noted that EFED cannot
quantitatively assess the relationship between any of the observed
sublethal effects and potential reduction in survival or reproductive
impairment at this time.  Instead, the concentrations at which sublethal
effects were observed in laboratory studies are discussed in relation to
the concentrations at which mortality and/or reproductive effects were
observed in the same laboratory studies and compared to aquatic and
terrestrial EECs and assessed as to whether or not they may be expected
under field conditions. The EU/UK formulation (BAS 560 00F), which is
used in all formulation studies, closely matches the U.S. formulation
(i.e., BAS 560 03F) but is not equivalent. The formulation studies are
cited and evaluated in this assessment. However, at this time, the
effect of the U.S. formulation on any given taxa is not known.

Acute Studies

Aquatic Organisms

The greatest amount of uncertainty in the assessment stems from aquatic
studies which were largely based on total concentrations (both dissolved
and undissolved) instead of the soluble concentrations of the test
compound.

Given the freshwater fish acute toxicity data the bluegill sunfish
(Lepomis macrochirus) appears to be more sensitive than the rainbow
trout (Oncorhynchus mykiss) on the technical grade active ingredient.
Sublethal effects (lethargic and motionless fish) were observed in the
bluegill study at the highest concentration tested (0.87 mg total
a.i./L) which is greater than the peak aquatic EEC (0.02 mg a.i./L).
Similarly, the lowest tested metabolite concentration at which sublethal
effects were observed for the trout study was at 20.3 mg total a.i./L,
which is also below the total metrafenone residue peak EEC. The numbers
imply that sublethal effects on freshwater fish due to the parent or
metabolite of metrafenone are not expected under field conditions.

The freshwater invertebrate study on daphnia using the technical grade
active ingredient and a metabolite (CL 375816) indicated no effects. On
the other hand, another metabolite study (using CL 4084564) indicated
immobility at 23.2 mg total a.i./L, which is also above peak EEC levels.
The numbers imply that sublethal effects on freshwater invertebrates due
to the parent or metabolite of metrafenone are not expected under field
conditions.

No effects were observed for the marine/estuarine fish technical grade
active ingredient study. Erratic swimming was observed in the saltwater
mysid (Americamysis bahia) study at 0.416 mg total a.i./L and mortality
at 0.129 mg total a.i./L, which are again above peak EEC levels.
Therefore, the values imply that sublethal effects on marine/estuarine
fish and invertebrates due to the parent metrafenone are not expected
under field conditions.

Terrestrial Organisms

The acute oral avian studies indicated no effects; the acute dietary
avian studies indicated a significant change in body weight that was not
associated with a dose-response pattern. In the mammal study on the
technical grade active ingredient, only mortality was reported.
Therefore, no implications with sublethal effects can be made.

Chronic Studies

Aquatic Organisms

The freshwater fish chronic toxicity endpoint (NOAEC 0.118 mg total
a.i./L) based on post-hatch is greater than the highest chronic EEC
(0.017 mg a.i./L). Similarly, the marine/estuarine invertebrate chronic
toxicity endpoint (NOAEC 0.022 mg a.i./L) based on reproduction is
greater than the highest chronic EEC (0.018 mg a.i./L). The values imply
that chronic effects on freshwater fish and marine/estuarine
invertebrates are not expected under field conditions.

No acceptable chronic freshwater invertebrate studies are available. No
chronic marine/estuarine fish studies were submitted for review.

Terrestrial Organisms

The avian chronic toxicity endpoint (NOAEC 848 mg a.i./kg diet) based on
egg production and hatchability did not yield chronic LOC exceedances.
The most sensitive chronic mammalian endpoint (NOAEL 35.9 mg/kg bw/day)
based on decreased body weights and body weight gain in F1 males as well
as body weights in F1 and F2 females, however, exceeded the chronic LOC,
which implies that sublethal chronic effects on mammals are expected
under field conditions.

Indirect Effects Analysis

In conducting a screen for indirect effects, direct effects LOCs for
each taxonomic group are used to make inferences concerning the
potential for indirect effects upon listed species.  The listed species
rely upon non-listed organisms in these taxonomic groups as resources
critical to their life cycle.  Pesticide-use scenarios, resulting in RQs
that are below all direct effect listed species LOCs for all taxonomic
groups assessed are considered of no concern for risks to listed species
either by direct or indirect effects.   However, there may be situations
where a taxonomic group is not quantitatively assessed (e.g.,
terrestrial insects), but other lines of evidence are sufficiently
supportive of concerns for indirect effects on listed organisms that are
dependant upon that taxonomic group.

Where One or More Animal Taxonomic Group RQs Exceed the LOC for Listed
Species

The Level I screening indirect effects analysis documents those types of
dependencies upon non-listed organisms that could be important sources
of indirect effects to listed organisms should effective levels of the
pesticide coincide with locations of listed species and the biologically
based resources upon which they depend.  In cases where screening-level
acute RQs for a given animal group equal or exceed the endangered
species acute LOC, the Agency uses the dose response relationship from
the toxicity study used for calculating the RQ to estimate the
probability of acute effects associated with an exposure equivalent to
the EEC.  This information serves as a guide to establish the need for
and extent of additional analysis that may be performed using
Services-provided “species profiles” as well as evaluations of the
geographical and temporal nature of the exposure to ascertain if a not
likely to adversely affect determination can be made.  The degree to
which additional analyses are performed is commensurate with the
predicted probability of adverse effects from the comparison of dose
response information with the EECs.  The greater the probability that
exposures will produce effects on a taxa, the greater the concern for
potential indirect effects for listed species dependant upon that taxa,
and therefore, the more intensive the analysis on the potential listed
species of concern, their locations relative to the use site, and
information regarding the use scenario (e.g., timing, frequency, and
geographical extent of pesticide application).  The greatest concerns
would exist when exposure is associated with a risk higher than the
effects probability associated with the non-endangered LOC for a
pesticide with an average slope of 4.5.

For metrafenone, risks to listed species are predicted within the
following taxa: mammals, freshwater fish and invertebrates,
marine/estuarine invertebrates, and marine/estuarine fish. Changes in
fish and aquatic invertebrate populations could indirectly affect other
fish and aquatic invertebrates, aquatic plants, birds, reptiles and
mammals.  The chronic endpoint for mammalian species is based on
decreases in body weight and/or body weight gain in both the parents and
pups.  If body size following chronic metrafenone exposure is reduced to
the extent that it has an impact on mammalian populations, reduction in
mammalian populations that are used as a resource for listed species may
be of concern.  Given that the chronic LOC is exceeded for mammals,
indirect effects to listed species (e.g., other mammals, birds,
amphibians, reptiles, plants (pollination) and terrestrial
invertebrates) that rely on mammals as a primary food source, or on
mammal burrows for shelter or breeding habitat, may be of concern.

Critical Habitat

In the evaluation of pesticide effects on designated critical habitat,
consideration is given to the physical and biological features
(constituent elements) of a critical habitat identified by the U.S Fish
and Wildlife and National Marine Fisheries Services as essential to the
conservation of a listed species and which may require special
management considerations or protection.   The evaluation of impacts for
a screening level pesticide risk assessment focuses on the biological
features that are constituent elements and is accomplished using the
screening-level taxonomic analysis (risk quotients, RQs) and listed
species levels of concern (LOCs) that are used to evaluate direct and
indirect effects to listed organisms.

The screening-level risk assessment has identified potential concerns
for indirect effects on listed species for those organisms dependant
upon mammals, freshwater fish and invertebrates, marine/estuarine
invertebrates, and marine/estuarine fish. In light of the potential for
indirect effects, the next step for EPA and the Service(s) is to
identify which listed species and critical habitat are potentially
implicated.  Analytically, the identification of such species and
critical habitat can occur in either of two ways.  First, the agencies
could determine whether the action area overlaps critical habitat or the
occupied range of any listed species.  If so, EPA would examine whether
the pesticide's potential impacts on non-endangered species would affect
the listed species indirectly or directly affect a constituent element
of the critical habitat.  Alternatively, the agencies could determine
which listed species depend on biological resources, or have constituent
elements, that fall into the taxa that may be directly or indirectly
impacted by the pesticide.  Then EPA would determine whether use of the
pesticide overlaps the critical habitat or the occupied range of those
listed species.  At present, the information reviewed by EPA does not
permit use of either analytical approach to make a definitive
identification of species that are potentially impacted indirectly or
critical habitat that is potentially impacted directly by the use of the
pesticide. EPA and the Service(s) are working together to conduct the
necessary analysis.

This screening-level risk assessment for critical habitat provides a
listing of potential biological features that, if they are constituent
elements of one or more critical habitats, would be of potential
concern.  These correspond to the taxonomic groups identified above as
being of potential concern for indirect effects (i.e., mammals,
freshwater fish and invertebrates, marine/estuarine invertebrates, and
marine/estuarine fish).  This should serve as an initial step in problem
formulation for further assessment of critical habitat impacts outlined
above, should additional work be necessary.

Co-occurrence Analysis

The goal of the analysis for co-location is to determine whether sites
of pesticide use are geographically associated with known locations of
listed species.  At the screening level, this analysis is accomplished
using the LOCATES v. 2.10.4 database.  The database uses location
information for listed species at the county level and compares it to
agricultural census data for crop production at the same county level of
resolution.  The product is a listing of federally listed species that
are located within counties known to produce the crop upon which the
pesticide will be used.

Tables 36 and 37 below report the number of states and counties in which
endangered species reside that have the proposed metrafenone use. The
‘grape’ category was selected in LOCATES.  The data suggest that
there is considerable potential for exposure to a variety of endangered
species from metrafenone use. For additional LOCATES output refer to
Appendix E.

	Species Counts by State for Indicated Crops

	No species were excluded.

	Minimum of 1 Acre.

	All Medium Types Reported

	grapes

AL, AK, AZ, AR, CA, CO, CT, DE, DC, FL, GA, HI, ID, IL, IN, IA, KS, KY,
LA, ME, MD, MA, MI, MN, MS, MO, MT, NE, NV, NH, NJ, NM, NY, NC, ND, OH,
OK, OR, PA, PR, RI, SC, SD, TN, TX, UT, VT, VA, WA, WV, WI, WY

Table 36.  Number of Endangered Species Potentially Exposed to
Metrafenone with the Proposed Uses

	Mammals	Amphibians	Birds	Reptiles	Arachnids	Insects	Conf/Cyc	Dicot
Ferns	Lichen	Monocots

Counties	744	93	595	231	12	153	6	493	28	14	272

States	47	11	43	24	4	28	3	41	8	4	37

Species	129	21	163	74	13	73	4	607	20	4	109

Table 37.  Number of Endangered Species Potentially Exposed to
Metrafenone with the Proposed Uses

	Bivalve	Crustacean	Fish	Gastropod	Marine Mammal

Counties	290	56	449	44	50

States	27	13	38	16	7

Species	205	21	197	32	10

Description of Assumptions, Limitations, Uncertainties, Strengths, and
Data Gaps

Assumptions, Limitations, and Uncertainties Related to Exposure for all
Taxa

Maximum Use Scenario

The screening-level risk assessment focuses on characterizing potential
ecological risks resulting from a maximum use scenario, which is
determined from labeled statements of maximum  application rate and
number of applications with the shortest time interval between
applications.  The frequency at which actual uses approach this maximum
use scenario may be dependant on fungicide resistance, timing of
applications, cultural practices, and market forces.

Assumptions, Limitations, and Uncertainties Related to Exposure for
Aquatic Species

Environmental Fate Studies

All of the environmental fate studies for the parent compound were
determined to be scientifically valid and therefore results from all of
the studies can be used to characterize the mobility and rates of
transformation of metrafenone.  However, many of the metabolism studies
have major uncertainties in the identification and pattern of formation
and decline of transformation products.  In all of the aquatic
metabolism studies, between 57% and 65% of the applied radioactivity
remains unidentified with incomplete characterization, and in two
aerobic soil metabolism studies, 15% and 44% of the applied
radioactivity is unidentified.  This includes at least four major
degradates that individually reach levels of 11% to 35% of the applied.
Other transformation products appear as groups of up to 15 components,
in some cases characterized as each being <5% of the applied
radioactivity, but in other cases, some individual components make up 9%
to 10% of the applied.  Even when individual components can all be
classified as minor degradates, these groups represent such a large
portion of the applied radioactivity overall that the possibility that
they may have some impact as a group cannot be precluded despite their
lower individual levels.  This is especially true given that the
degradation pathways suggest that groups of degradates may have a high
degree of structural similarity and so may have similar fate and effects
behavior.  Without information to adequately characterize the
degradates, it may be necessary to assume that they are of equal
toxicity to the parents in order to quantify risks.

Aquatic Exposure Modeling

The lack of complete characterization and identification of degradation
products prompted additional aquatic exposure modeling on total
metrafenone residues.  Although this modeling approach is conservative,
it is reasonable modeling approach to address uncertainties in
degradation product identification.

Bioaccumulation Modeling

Bioaccumulation modeling was conducted because metrafenone has a log Kow
> 4.  The bioaccumulation modeling was conducted using guidance for the
KABAM model.  It is recommended to report the sediment pore water and
water column concentrations at the appropriate time when the pesticide
concentration reaches steady-state.  An evaluation of the time series
for metrafenone showed no clear plateau in metrafenone concentrations.
Therefore, the appropriate averaging time was selected at 21 days to
serve as a conservative exposure concentration for bioaccumulation
modeling.

Assumptions, Limitations, and Uncertainties Related to Exposure for
Terrestrial Species

Location of Wildlife Species

For this screening-level terrestrial risk assessment, a generic bird or
mammal was assumed to occupy either the treated field or adjacent areas
receiving metrafenone at the treatment rate on the field.  Actual
habitat requirements of any particular terrestrial species were not
considered, and it was assumed that species occupy, exclusively and
permanently, the modeled treatment area.  Spray drift model predictions
suggest that this assumption leads to an overestimation of exposure to
species that do not occupy the treated field exclusively and
permanently.

Routes of Exposure

This screening-level assessment for ground (liquid) applications of
metrafenone only considered dietary exposure. Other routes of exposure
that were not considered in the assessment are incidental soil ingestion
exposure, inhalation exposure, dermal exposure, and drinking water
exposure.

Dietary Intake and Other Limitations of Oral Studies in Terrestrial
Species

The avian acute oral study and the avian subacute dietary study each
have limitations for estimating the risk to wild species exposed to
pesticides in the environment.  Both studies have a fixed exposure
period and do not allow for differences in the responses of individuals
to different durations of exposure.  With the acute oral study, the
chemical is administered in a single dose.  This does not mimic wild
bird exposure through multiple feedings.  Also, it does not account for
the effect of different environmental matrices on absorption rate into
the gastrointestinal tract of the animal.  With the acute dietary study,
the endpoint is reported as the concentration mixed with food that
produces a response rather than as the dose ingested.  Although food
consumption sometimes allows for estimation of a dose, calculations of
the mg/kg/day are confounded by undocumented spillage of feed and how
consumption is measured over the duration of the test.  Usually, if
measured at all, food consumption is estimated once at the end of the
five-day exposure period.  Group housing of birds undergoing testing
allows for a measure of only the average consumption per day for a
group, and consumption estimates can be further confounded if birds die
within a treatment group.  In addition, the dietary study utilizes young
birds.  The exponential growth of young birds complicates the estimate
of the dose; controls often nearly double in size over the duration of
the test.  Since weights are only taken at the initiation and at the end
of the exposure period, the dose per body weight (mg/kg) is difficult to
estimate with any precision.  The interpretation of this test can be
further confounded by dietary consumption.  Estimation of the acute LC50
value is not only a function of the intrinsic toxicity of the pesticide,
but also the willingness of the birds to consume treated food.

In addition to the uncertainties associated with the two toxicity
studies utilized for estimating acute risk to birds, other factors, not
normally taken into account in a screening level risk assessment may
narrow the differences between the dose-based and dietary-based acute
RQs for birds. The factors include differences in gross energy and
assimilative efficiency of laboratory feed versus food items in the
field, basic maintenance metabolic rates between wild birds and captive
birds, seasonal free living dietary requirements for wild birds
(including gorging behavior) and specific food avoidance behavior.
These uncertainties may either overestimate or underestimate the risk in
a screening level assessment.

Gross Energy and Assimilative Efficiency. This screening level risk
assessment does not allow for gross energy and assimilative efficiency
differences between wildlife food items and laboratory feed.  For
example, a typical laboratory avian feed, as used, contains
approximately 2750 kcal/ kg.  The Agency’s Wildlife Exposure Factors
Handbook (U.S. Environmental Protection Agency, 1993) presents the
following dry-weight and fresh weight caloric contents for selected
wildlife food items:

Food Item		Energy Dry (kcal/kg)		Energy Fresh (kcal/kg)

grasses				4200				1300

broadleaf forage		4200				2200

seeds				5100				4700

fruits				2000				1100

insects				5600				1600

On gross energy content alone, direct comparison of a laboratory dietary
concentration-based effects threshold to a fresh-weight pesticide
residue estimate would result in an underestimation of field exposure by
food consumption by a factor of 1.25 - 2.5 for most food items.  Only
for seeds would the direct comparison of dietary threshold to residue
estimate lead to an overestimate of exposure.

Depending upon species and dietary matrix, bird assimilation of wild
diet energy ranges from 23 - 80%, and mammal’s assimilation ranges
from 41 - 85% (U.S. EPA, 1993).  If it is assumed that laboratory chow
is formulated to maximize assimilative efficiency (e.g., a value of
85%), a potential for underestimation of exposure may exist by assuming
that consumption of food in the wild is comparable with consumption
during laboratory testing.

Metabolic Rates.  In the screening process, exposure may be
underestimated because metabolic rates are not related to food
consumption.   For example, the Wildlife Exposure Factors Handbook (U.S.
EPA, 1993) includes allometric models for estimating both existing
metabolic rate (EMR) and free living metabolic rate (FMR).  EMR is the
metabolic rate necessary for animal maintenance in captivity without
body weight loss, a condition similar to caged test animals.  FMR is the
energy requirement for an organism in the wild.  For passerine birds
these relationships are as follows:

EMR (kcal/day) = 1.572 (body weight g) 0.6210

FMR (kcal/day) = 2.123 (body weight g) 0.749

Using a weight range for passerines of 10 - 150 g, the EMR predictions
range from 6.6 to 35.3, and the FMR ranges from 11.9 to 90.5 kcal/day.
Thus, it appears that not accounting for increased energy demands of
organisms in the wild when comparing dietary residues to dietary
toxicity thresholds represents about a two-fold underestimation in
exposure potential.

Free Living Metabolic Requirements.  The screening procedure does not
account for situations where the feeding rate may be above or below
requirements to meet free living metabolic requirements.  Gorging
behavior is a possibility under some specific wildlife scenarios (e.g.,
bird migration) where the food intake rate may be greatly increased.
Kirkwood (1983) has suggested that an upper-bound limit to this behavior
might be the typical intake rate multiplied by a factor of 5.

Avoidance.  In contrast is the potential for avoidance, operationally
defined as animals responding to the presence of noxious chemicals in
their food by reducing consumption of treated dietary elements.  This
response is seen in nature where herbivores avoid plant secondary
compounds.  For agrochemicals, Dolbeer et al. (1994) reported that the
use of methiocarb on fruit crops reduced depredation by birds.  Of
course, chemical treatment of food sources and any subsequent avoidance
of those food sources by a species may, in itself, result in detrimental
effects on the energetics of the species.

Incidental Releases Associated with Use

This risk assessment was based on the assumption that the entire
treatment area is subject to pesticide application at the rates
specified on the label. Uneven application of the pesticide through
changes in calibration of application equipment, spillage, and localized
releases at specific areas of the treated field that are associated with
specifics of the type of application equipment were not accounted for in
this assessment.

Residue Levels Selection

The Agency relies on the work of Fletcher et al. (1994) for setting the
assumed pesticide residues in wildlife dietary items.  These residue
assumptions are believed to reflect a realistic upper-bound residue
estimate, although the degree to which this assumption reflects a
specific percentile estimate is difficult to quantify.  It is important
to note that the field measurement efforts used to develop the Fletcher
estimates of exposure involve highly varied sampling techniques.  It is
entirely possible that much of these data reflects residues averaged
over the entire above ground plants in the case of grass and forage
sampling.  Depending upon a specific wildlife species’ foraging
habits, whole aboveground plant samples may either underestimate or
overestimate actual exposure.

TerrPlant Model

At this time, the TerrPlant model cannot accurately estimate terrestrial
exposure levels with pesticides applied with multiple applications or
application intervals.  The technology is not yet available for these
types of estimations.  The label states that a maximum of 1.8 lbs a.i./A
may be applied per season, with a maximum of six applications the
highest single application rate is 0.3 lbs a.i./A.  In modeling the
terrestrial EECs, it was assumed that there was one application per
year. If assuming one application of 1.8 lbs a.i./A the RQ values may be
considered an overestimate of risk, but assuming one application of 0.3
lbs a.i./A the RQ values may be considered an underestimate of risk.
Therefore, the model was used to bracket the potential risk on
terrestrial plants as a result of metrafenone use.

Assumptions, Limitations, and Uncertainties Related to Effects
Assessment

Sublethal Effects

For an acute risk assessment, the screening risk assessment relies on
the acute mortality endpoint as well as a suite of sublethal responses
to the pesticide, as determined by the testing of species response to
chronic exposure conditions and subsequent chronic risk assessment.
Consideration of additional sublethal data in the assessment is
exercised on a case-by-case basis and only after careful consideration
of the nature of the sublethal effect measured and the extent and
quality of available data to support establishing a plausible
relationship between the measure of effect (sublethal endpoint) and the
assessment endpoints.

Age Class and Sensitivity of Effects Thresholds

Testing of juvenile organisms may overestimate toxicity at older age
classes for pesticidal active ingredients that act directly (without
metabolic transformation) because younger age classes may not have the
enzymatic systems associated with detoxifying xenobiotics. However, the
influence of age may not be uniform for all compounds, and compounds
requiring metabolic activation may be more toxic in older age classes.
The risk assessment uses the most sensitive life-stage information as
the conservative screening endpoint.

Use of Most Sensitive Species Tested

Screening risk assessment relies on a selected toxicity endpoint from
the most sensitive species tested; however, the selected toxicity
endpoints do not necessarily reflect sensitivity of the most sensitive
species in a given environment. The relative position of the most
sensitive species tested in the distribution of all possible species is
a function of the overall variability among species to a particular
chemical. Toxicity thresholds may vary up to four orders of magnitude
across species for some chemicals.  Therefore, risk conclusions may
under- or overestimate actual ecological risk for a given species.

Assumptions, Limitations, Uncertainties, Strengths, and Data Gaps
Related to the Acute and Chronic LOC’s

The risk characterization section of the assessment document includes an
evaluation of the potential for individual effects to listed species at
an exposure level equivalent to the LOC.  This evaluation is based on
the median lethal dose estimate and dose/response relationship
established for the effects study corresponding to each taxonomic group
for which the LOCs are exceeded.  The slope of the probit-dose response
is used to generate a probability of individual effects near the low end
tail of the curve.  Predictions based on low probability events are by
nature highly uncertain.  Moreover, for this assessment the
dose-response curve representing a given taxa is generated from one
study using one species.  It is likely that the resulting dose-response
relationship does not represent the response of all species within a
taxa.  Calculating the probability of individual effects at the lower
and upper bounds of the slope is designed to address this source of
uncertainty but the extent to which this captures the variability within
a taxa is unknown.  In some cases, a probit dose-response relationship
cannot be calculated.  In these instances, event probabilities are
calculated based on a default slope assumption of 4.5 (Urban and Cook,
1986).

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MRID 47267450

Zulalian, J.  2001.  BAS 560 F (AC 375839): uptake, depuration,
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MRID 47267436

Xing, J.  2002.  BAS 560 F (CL 375839): laboratory validation of LC/MS
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MRID 47267435

Travis, D.  2002.  BAS 560 F (CL 375839): laboratory validation of LC/MS
determinative and LC/MS/MS confirmatory method M 3441 for the
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MRID 47267434

Smalley, R.  2001.  Method validation of RLA 12618.00 "LC-MS
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MRID 47267431

Panek, M, et al.  2008.  Anaerobic aquatic metabolism of 14C-BAS 560 F.
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MRID 47267430

Yan, Z. and R.A. Huang.  2002.  BAS 560 F (AC 375839): aerobic
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MRID 47267429

Huang, R.  2002.  BAS 560 F: anaerobic soil metabolism.  Unpublished
study performed, sponsored and submitted by BASF Corporation, Research
Triangle Park, North Carolina.

MRID 4726728

Afzal, J. 2002.  CL 377160 (metabolite of BAS 560 F) rate of degradation
in three different soils under aerobic conditions.  Unpublished study
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MRID 47267427

Singh, M. 2008.  Aerobic soil metabolism of 14C-BAS 560 F on US soils.
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MRID 47267426

Steinführer, T.  2000.  14C-AC 375839 (CL 375839) Rate of degradation
in three different soils under aerobic conditions.  Unpublished study
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MRID 47267425

Steinführer, T.  2000.  AC 37589: Metabolism in soil under aerobic
conditions.  Unpublished study performed by Cyanamid Forschung GmbH,
Schwabenheim, Germany.

MRID 47267424

Ta, C. 2001.  BAS 560 F (AC 375839): Soil photolysis.  Unpublished study
performed by BASF Agro Research, Ewing, New Jersey.

MRID 47267423

Fung, C.H.  2002.  BAS 560 F (AC 375839): Aqueous photolysis.
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MRID 47267422

An, D.  1999.  AC 375839: Hydrolysis.  Unpublished study performed by
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MRID 47267421

Tornisielo, A. and R. Hoefs. 2008.  Adsorption/desorption of a
metabolite of BAS 560 F (Reg. No. 4082230) on US soils (including
Amendment No. 1).  Unpublished study performed by BASF SA,
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Research Triangle Park, North Carolina.

MRID 47267421

Tornisielo, A. and R. Hoefs. 2008.  Adsorption/desorption of BAS 560 F
on US soils (including Amendment No. 1).  Unpublished study performed by
BASF SA, Guaratingueta, Brazil; and sponsored and submitted by BASF
Corporation, Research Triangle Park, North Carolina

MRID 47267432

Jordan,J. J.M. Stewart, and R. Warren. 2008. Terrestrial field
dissipation of BAS 560 00F in vineyard/orchard and row crop use
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phase), Vaughn Agricultural Research Services, Branchton, Ontario (field
phase), Research Options, Inc., Winter Garden, Florida (field phase),
BASF RTP, NC (analytical phase); and Agvise Laboratories, Inc. Northwood
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Effects Studies Submitted to the USEPA/Office of Pesticide Programs

MRID 47267502

Ahmed, M.S., R. Troup and T. Harris. 2000(a). Avian acute oral toxicity
test with AC 375839 Technical in Northern Bobwhite (Colinus
virginianus). BASF Doc ID 2000/7000117.

MRID 47267503

Ahmed, M.S., R. Troup and T. Harris. 2000(b). Avian acute oral toxicity
test with AC 375839 Technical in Mallard Duck (Anas platyrhynchos). BASF
Doc ID 2000/7000115.

MRID 47267504

Ahmed, M.S., R. Troup and T. Harris. 2000(c). Avian dietary toxicity
test with AC 375839 Technical in Northern Bobwhite (Colinus
virginianus). BASF Doc ID 2000/7000126.

MRID 47267505

Ahmed, M.S., R. Troup and T. Harris. 2000(d). Avian dietary toxicity
test with AC 375839 Technical in Mallard Duck (Anas platyrhynchos). BASF
Doc ID 2000/7000125.

MRID 47267506

Ahmed, M.S. and M. Rodgers. 2002. BASF: Assessment to determine the