46.9, and 193.9 mg/kg bw/day for F1 females.  The premating period was
10 weeks.  The males received the treated or control diets continuously
until sacrificed when almost all their litters were weaned, and the
females received the diets during premating, mating, gestation, and
lactation until sacrifice after weaning their litters.

No treatment-related effects were observed on survival or clinical signs
in any group of parental

male or female rats in either generation.  Absolute body weight and
weight gain were

significantly decreased but were within 10% of that of controls in F0
and F1 males during

premating/postmating periods and in female rats during premating except
as noted below.  High-

dose F0 females gained up to 14% (p<0.01) less weight than controls and
high-dose F1 males

weighed 11% (p<0.01) less than controls on day 4 of premating because of
the significantly

decreased male pup weight at weaning.  Food consumption was
significantly decreased during a

few weekly intervals in high-dose F0 and F1 males and females, but was
within 10% of that of

controls.  Food efficiency was not significantly affected by treatment
of male or female rats in

either generation.  No treatment-related effect was observed on body
weight, weight gain, food

consumption, or food efficiency in low- or mid-dose male or female rats
of either generation.

In high-dose pregnant females, body weight was significantly decreased
by 7% on GD 6 and 13

in the F0 generation and by 10-11% throughout gestation in the F1
generation compared with that

 of controls.  Both generations gained 14-16% (p<0.01) less weight than
controls during the first

13 days of gestation, but weight gain was similar to or greater than
that of controls after GD 13.

A 13% decrease in body weight gain in mid-dose F0 females during GD 0-6
was not

accompanied by a decrease in body weight.  High-dose  F0 and F1
lactating females had body

weight up to 8% and 13% (p<0.01) less, respectively, than controls, but
weight gain was not

significantly affected.  High-dose F0 and F1 females consumed up to 12%
(p<0.01) less food than

controls during the first 13 days of lactation.

Postmortem evaluation showed treatment-related and toxicologically
significant effects only in

the kidneys.  High-dose F0 and F1 males had small, statistically
significant increases in absolute

and relative kidney weights and high-dose F0 and F1 females had
significant increases in relative

kidney weight.  No treatment-related gross lesions were observed in male
or female rats in either generation.  Treatment-related and
toxicologically significant histopathologic lesions were

observed in the kidneys of high-dose F0 and F1 male and female rats.
The incidences of  cortical tubular basophilia, medullary granular
casts, and cortical scarring were significantly increased in high-dose
F0 and F1 males compared with the control incidences.  The incidence of
interstitial inflammation was significantly increased in high-dose F0
males.  The increased incidences of cortical tubular dilatation and
cortical granular casts in high-dose F1 males did not reach statistical
significance but were considered treatment related.  In high-dose F0 and
F1 female rats, the incidences of cortical tubular basophilia and
cortical tubular dilatation were significantly increased and the
increased incidence of  corticomedullary mineralization was not
statistically significant but was considered treatment related.

The lowest-observed-adverse-effect level (LOAEL) for systemic toxicity
of AE C638206 in

rats is 2000 ppm (144.6-179.9 mg/kg bw/day in males and 159.7-193.3
mg/kg bw/day in

females) based on decreases in weight gain in F0 females and kidney
toxicity in F0 and F1

males and females.  The no-observed-adverse-effect level (NOAEL) is 500
ppm (36.4-43.7

mg/kg bw/day in males and 41.0-46.9 mg/kg bw/day in females).

Evaluation of reproductive parameters showed no treatment-related
effects on estrous cycle

periodicity or length, sperm measures (motility or sperm count),
precoital interval, gestation

length, or reproductive indices (mating, conception, fertility, and
gestation) in either generation.

The numbers of implantation sites and viable litters were similar in the
treated and control

groups in both generations.  No treatment-related gross or microscopic
lesions were observed in

reproductive organs.

The lowest-observed-adverse-effect level (LOAEL) for reproductive
toxicity of AE

C638206 in rats was not determined; therefore the
no-observed-adverse-effect level

(NOAEL) is >2000 ppm (>179.9 mg/kg bw/day in males and >193.3 mg/kg
bw/day in

females).

No treatment-related effects were observed on the behavior or other
clinical signs of offspring of

either generation.  No treatment-related effects were observed on litter
size, sex ratio, or any

survival index (postimplantation survival, live birth, viability, and
lactation indices) in F1 or F2

offspring.  The day of attainment of sexual maturation and the body
weight at attainment were

not affected by treatment with the test material in male or female F1
offspring.  Body weight was

significantly reduced by 7-13% in high-dose group F1 and F2 male and
female pups 14, 21, and

28 days old.  Weight gain over the 28-day postnatal period was
significantly decreased by 8-9%

in high-dose F1 male and female pups and by 11-14% in high-dose F2 male
and female pups

compared with that of controls due primarily to decreases in weight gain
occurring after

postnatal day 7.  Statistically significant changes in organ weights in
F1 and F2 weanlings

(absolute and/or relative spleen, thymus and/or brain) were not
accompanied by gross lesions in

these organs and microscopic examinations were not conducted.

The lowest-observed-adverse-effect level (LOAEL) for offspring toxicity
of AE C638206 in

rats is 2000 ppm (144.6-179.9 mg/kg by/day in males and 159.7-193.3
mg/kg bw/day in

females) based on decreases in body weight and weight gain F1 and F2
male and female

pups.  The no-observed-adverse-effect level (NOAEL) is 500 ppm
(36.4–43.7 mg/kg bw/day

for males and 41.0-46.9 mg/kg bw/day in females).

Kidney toxicity was observed in the parental animals at the high-dose
level; therefore, the

animals in this study were adequately dosed to assess both reproductive
and offspring toxicity.

This study is Acceptable/Guideline and it satisfies the guideline
requirement for a two-

generation reproductive study (OPPTS 870.3800); OECD 416 in rats.

A.3.4	Chronic Toxicity

	870.4100a (870.4300) Chronic Toxicity – Rat

A combined chronic toxicity/carcinogenicity study in rats is included in
section A.3.5 below.

	870.4100b Chronic Toxicity – Dog

In a chronic toxicity study (MRID 46474128) AE C638206 (95.9%, Lot No.
OP2050046) was administered to 5 beagle dogs/sex/dose by oral gavage at
concentrations of 0, 70, 300 and 1000 mg/kg/day for 52 weeks.

There were no significant compound-related effects based on mortality,
clinical signs, food consumption, opthalmoscopic examinations,
urinalysis, hematology, clinical chemistry, organ weight, gross
pathology or histopathology.  Body weight gain was inhibited in males
treated with 1000 mg fluopicolide/kg/day.  Although increased
cholesterol concentrations at the end of the study were statistically
significant and slightly above the historical range in females treated
with 1000 mg/kg/day, there were no correlative changes indicating an
exposure-related effect on lipid metabolism in these animals.  One
female in the 300 mg/kg/day dosage group died during the study, however,
the death was not conclusively associated with exposure to fluopicolide.

The LOAEL for AE C638206 in male dogs was 1000 mg/kg/day based on
decreased body weight gain.  The NOAELs were 300 and 1000 mg/kg/day for
males and females, respectively.

This chronic study in the dog is Acceptable/Guideline and satisfies the
requirement for a chronic oral study [OPPTS 870.4100, OECD 452] in a
non-rodent.

A.3.5	Carcinogenicity

	870.4200a Carcinogenicity Study – rat

In a combined chronic toxicity/carcinogenicity study (MRID 46474139), AE
C638206 (Fluopicolide, 95.9%, a.i.; Batch No. OP2050046) was
administered to 60 Crl:CD (SD) IGS BR rats/sex/dose in the diet at
concentrations of 0 (controls), 50, 200, 750 or 2500 ppm (equivalent to
0, 2.1, 8.4, 31.5 or 109.4 mg/kg bw/day in males and 0, 2.8, 10.8, 41.0
or 142.2 mg/kg bw/day in females) for up to 104 weeks.  An additional 20
animals/sex/dose were administered the same concentration and sacrificed
after 52 weeks of treatment for a interim sacrifice.  A third set of 10
animals/sex/dose were fed the treated diet at the same concentrations
for 52 weeks followed by 13 weeks of being fed basal diet prior to
sacrifice in a recovery study.  A report, MRID 46474138, which consisted
of a summary of the study profile was provided as an additional source
of information.

Statistical analysis showed no increased incidence of mortality in any
of the treated groups

compared to controls.  The only clinical signs observed were in the
females rats and consisted of

yellow perigenital staining, brown staining of the pinna and brown
staining of the dorsum.

Statistical significance was not evaluated for these clinical signs.
Yellow perigenital staining and

the brown staining of the pinna was observed primarily in the 2500 ppm
females in the main

study with these signs beginning around week 13 and increasing to weeks
47-53 when they were

observed in 21-31% of the females at 2500 ppm.  Both effects then
started to diminish and were

seen in few animals (<5%) by the end of the second year.  Similar
results were observed in the

52 week study.  Brown staining of the dorsum was observed but was not
seen in a concentration-

related increase, affecting controls as well as treated females.  These
clinical signs appear to be

of low toxicological significance due to a lack of corresponding
urinalysis, clinical chemistry or

histopathology effects identified, and they were transient with most
effects minimizing after the

first year.  While palpable masses were observed and monitored, there
was not a treatment-

related increase in the incidence of these masses.

There was no statistically significant difference in body weight in any
of the treated groups.  A

statistically significant (p< 0.05 or p<0.01) decrease in mean body
weight gain was observed in

weeks 0-1 in both studies at the highest dose in males (33%) and females
(28%), compared to

controls.  In the main study, a statistically significant (p<0.01)
decrease was also seen in the

females at 200 (20%) and 750(32%) ppm groups.  The only significant
decrease in body weight

gain in weeks 1-2 of the main study was in males at 2500 ppm and females
at 50 and 2500 ppm,

 and these gains were decreased 11% in the males and 15 and 42% in the
females, respectively,

compared to controls.  After this time, body weight and body weight gain
remained lower than

controls (n.s.) with the overall body weight gain of the 2500 ppm group
being 11% and 17% less

than controls in the males and females, respectively.  In the animals
dosed for 52 weeks, the

similar effect of decreased body weight gain in the highest dosed males
and females was

observed with statistical significance in the first 2 weeks.  Both male
and female rats had

comparable body weight gain by the end of the recovery period.  A
corresponding decrease in

food consumption and food efficiency was observed in the highest dosed
group of males and

females during the first two weeks of treatment; however, statistical
analysis was not included in

the report.

Statistical differences in hematology and clinical chemistry were not
toxicologically significant.

Those observed were minor, sporadic and did not have a clear
treatment-related association.

Statistically significant increases (p<0.01 or 0.05) in relative (to
body weight) and absolute

kidney (122- 137%), thyroid (154-163%) and liver (122-134%) weights were
observed in the

males at 2500 ppm in the main study.  These same increases were observed
in the males at 2500

ppm in the 52 week study, except for absolute kidney weight.  Females at
2500 ppm in the 52

week study had statistically significant increases in relative, but not
absolute, liver and kidney

weights; this was associated with a significant decrease in terminal
body weight.

Males had a statistically significant increase in the incidence of and
severity of non-neoplastic

microscopic lesions in the thyroid, kidney and liver in the main study.
A corresponding increase

(p< 0.05) in the incidence of enlarged kidneys and thyroids were present
in the males at 2500

ppm compared to controls on gross observation.  On histopathological
examination, an increased

incidence of thyroid cystic follicular hyperplasia was present in the
males and observed in 0/60,

1/37, 0/37, 4/35 and 7/60 (p < 0.05) in the controls, 50, 200, 750 or
2500 ppm males.  Lesions in

the kidney were those associated with the alpha -2u-globulin
accumulation normally present in

male aged rats and are not considered adverse or applicable to human
risk assessment.  The liver

effect, centrilobular hepatocyte hypertrophy, observed both at 52 and
104 weeks was considered

to be an adaptive change due to treatment.  During the recovery period,
all lesions present were

reversed except for a slight increase in the severity of the renal
cortical tubular basophilia in the

males.  Females had no statistically significant differences in lesions
in any of the dose groups in

either the toxicity or the main study.

The lowest-observed-adverse effect level (LOAEL) for AE C638206 in rats
is 2500 ppm

(109.4 and 142.2 mg/kg/day for males and females, respectively) based on
decreases in body

weight gain (M and F) and an increase in thyroid organ weight with
corresponding

increases in the incidence of thyroid lesions (M only).  The
no-observed-adverse effect level

(NOAEL) for AE C638206 is 750 ppm (31.5 and 41.0 in males and females,
respectively).

At the doses tested, there was not a treatment related increase in tumor
incidence of any type in

animals dosed with up to 2500 ppm AE C638206 for up to 104 weeks.
Dosing was considered

adequate based on the decreased body weight gain in the male and female
rats at 2500 ppm, and

the non-neoplastic lesions observed at 2500 ppm in males.  While effects
were minimal in the

female, a reproductive study, MRID 46474124 (main study) and 46474125
(supplemental study

histopathological evaluation of liver and kidneys) indicated kidney
toxicity (microscopic

lesions) in male and female rats in both parental generations and
decreased body weight

gain in the F0 females treated with AC638206 for 16 weeks at 2000 ppm
indicating adequate dosing in this study at 2500 ppm.

This chronic/carcinogenicity study in the rat is Acceptable/Guideline
and satisfies the guideline

requirement for a chronic/carcinogenicity study [(OPPTS 870.4300); OECD
453] in rats.

	870.4200b Carcinogenicity (feeding) – Mouse

In a carcinogenicity study (MRID 46474130) AE C638206 (Fluopicolide)
(95.9% a.i., batch #OP2050046) was administered to 50 C57BL/6
mice/sex/dose in the diet at dietary levels of 0, 50, 400, or 3200 ppm
(equivalent to 0, 7.9, 64.5, 551.0 mg/kg bw/day for males, and 0, 11.5,
91.9, and 772.3 mg/kg bw/day for females) for 18 months.  Satellite
groups of 10 C57BL/6 mice/sex/dose were similarly treated for 12 months.
 Historical control incidences of hepatocellular lesions were provided
(MRID 46474135).

2/10 for each lesion).

The LOAEL for AE C638206 in mice is 3200 ppm for both sexes (551.0
mg/kg/day for males, 772.3 mg/kg/day for females), based on severely
decreased body weights and body weight gains and liver lesions in both
sexes.  The NOAEL is 400 ppm in both sexes (64.5 mg/kg/day for males,
91.9 mg/kg/day for females).

At the doses tested, there was a treatment related increase in the
incidence of hepatocellular adenoma when compared to controls.  The 3200
ppm animals had statistically significant increases in hepatocellular
adenoma in both sexes after 78 weeks, and a small increase after 52
weeks.  The adenoma incidence after 78 weeks at 0, 50, 400 and 3200 ppm
was 5/50, 0/50, 5/50, and 11/50, respectively, for males, and 1/50,
2/50, 0/50, and 16/50, respectively, for females.  After 52 weeks,
hepatocellular adenoma was found in 3/10 high-dose females but no males.
   The adenomas were correlated with an increased incidence of liver
masses and nodules at necropsy.  Dosing was considered adequate based on
decreased body weight gains, decreased food efficiency, and liver
lesions seen in both sexes at the high dose.

This carcinogenicity study is Acceptable/Guideline and satisfies
guideline requirements for a carcinogenicity study [OPPTS 870.4200b;
OECD 451] in mice.

A.3.6	Mutagenicity

	Gene Mutation

Guideline 84-2, Reverse gene mutation

MRID 46474146

Unacceptable/guideline

	dose range:  1.6 to 5000 µg/plate

No increases in revertant colonies were found in either test series at
concentrations up to the limit dose, 5000 µg/plate. Therefore,
AEC638206 00 IC99 0005 is considered nonmutagenic in the conventional
battery of bacterial strains.

This study was considered unacceptable/guideline because purity
information for the test material was not provided.

Guideline 84-2, Reverse gene mutation

MRID 46474202

acceptable/guideline

	dose range:  1.6 to 5000 µg/plate

No increases in revertant colonies were found in either test series at
concentrations up to the limit dose, 5000 µg/plate. Therefore,
AEC638206 00 IC99 0001 is considered nonmutagenic in the conventional
battery of bacterial strains.

Guideline 84-2, Reverse gene mutation

MRID 46474148

acceptable/guideline

	dose range:  1.6 to 5000 µg/plate

No increases in revertant colonies were found in either test series at
concentrations up to the limit dose, 5000 µg/plate. Therefore,
AEC638206 00 IB99 0002 is considered nonmutagenic in the conventional
battery of bacterial strains.

Guideline 84-2, Reverse gene mutation

MRID 46474144

acceptable/guideline

	dose range:  1.6 to 5000 µg/plate

No increases in revertant colonies were found in either test series at
concentrations up to the limit dose, 5000 µg/plate. Therefore,
AEC638206 Technical is considered nonmutagenic in the conventional
battery of bacterial strains.

Guideline 84-2, Reverse gene mutation

MRID 46474142

acceptable/guideline

	dose range:  5 to 5000 µg/plate

AE C638206 (fluopicolide) is considered mutagenic at precipitating
concentrations in the conventional battery of bacterial strains.

	Cytogenetics

Guideline 84-2, in vitro mammalian cells in culture/gene mutation assay
in Chinese hamster lung cells

MRID 46474204

Acceptable/guideline

	1.2 to 3820 µg/mL,  0.4 to 120 µg/mL and 0.313 to 60 µg/mL with and
without activation

No concentration in any of the three experiments was a biologically
relevant, reproducible increase in mutant colonies found at
concentrations up to the highest subcytotoxic levels.  Both positive
controls showed marked increases.

Guideline 84-2, in vivo mammalian chromosome
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In the presence of  ≥50% reduction in the MI, no statistically
significant increases in the structural or numerical (polyploidy)
aberrant metaphases were found at any test concentration in either
trial, compared to marked (p≤0.001) increases in both positive
controls.

Guideline 84-2, in vitro mammalian chromosome aberrations

MRID 46474206

Acceptable/guideline

	3.2 to 100 µg/mL with and without activation; 0.1 to 6.3 µg/mL
without activation

This batch mixture of AE C638206 is considered a clastogen in the in
vitro Chinese hamster lung (V79) cell system in the absence of S9
activation.

Guideline 84-2, in vivo mammalian cytogenetics

MRID 46474214

Acceptable/guideline

	IP injection of 150, 300 or 600 mg/kg/day

No dose up to the HDT was a significantly increased number of mPCEs
recorded, in the presence of a statistically increased ratio of PCEs to
NCEs (evidence of interference with erythropoiesis), either when
compared to vehicle controls, or to the laboratory’s 8-year historical
control data base. The positive control registered a marked increase in
mPCEs, in the absence of any alteration of erythropoietic effects.

Guideline 84-2, in vivo mammalian cytogenetics

MRID 46474210

Acceptable/guideline

	Two oral doses of 200, 600, or 2000 mg/kg/day, 24 hours apart

No adverse clinical signs were observed during the main study. The ratio
of polychromatic to normochromatic erythrocytes was unaffected by
treatment. Additionally, at no dose level up to the limit dose, (2000
mg/kg/day), were increased numbers of mPCEs induced by the test article,
compared with the marked increases observed in CPA-treated cells.

	Other Genotoxicity

Guideline (no # given),  Unscheduled DNA synthesis in hepatocytes

MRID 46474216

acceptable/guideline	600 or 2000 mg/kg

There was no evidence (or a dose-related positive response) that
unscheduled DNA synthesis, as determined by radioactive tracer
procedures (nuclear silver grain counts) was induced at either timed
sacrifice in rats exposed to the test material up to the limit dose
(2000 mg/kg).

A.3.7	Neurotoxicity

	870.6100 Delayed Neurotoxicity Study – Hen

Not required for this chemical.

	870.6200 Acute Neurotoxicity Screening Battery

In an acute neurotoxicity study (MRID 46474218; summarized in MRID
46474217), groups of fasted, 6- to 7-week old CD rats (10/sex) were
given a single oral dose of AE C638206 (95.9% a.i., batch/lot
#OP2050046) in 1% methylcellulose at doses of 0, 10, 100, or 2000 mg/kg
bw and observed for 15 days.  Doses were based on a range-finding study
in which single doses of 50 mg/kg induced behavioral changes (MRID
46474219).  Neurobehavioral assessment (functional observational battery
[FOB] and motor activity testing) was performed in 10 animals/sex/group
pretreatment, on Day 1 (at six hours post-dosing, the time of peak
effect), and on Days 8 and 15.  Cholinesterase activity was not
determined.  At study termination, 5 animals/sex/group were euthanized
and perfused in situ for neuropathological examination.  Of the perfused
animals, the control and high-dose groups were subjected to
histopathological evaluation of brain and peripheral nervous system
tissues.

There was no effect of treatment on body weight, body weight gain, food
consumption, food efficiency, brain weight, brain measurements (cerebral
hemispheres), or incidence of gross or microscopic lesions.  Lower body
temperature in the high-dose males and females at the time of peak
effect (6 hours post-dosing) on the day of treatment (Day 1) was the
only treatment-related observation during the FOB.  This sign was not
observed on Days 8 or 15.  A statistically significant decrease in
forelimb grip strength in females in the 2000 mg/kg group on Day 8,
reduced motor activity of males in the 2000 mg/kg treatment group on Day
1, and increased motor activity in females in the 2000 mg/kg group on
Day 15 were considered incidental to treatment as these effects were not
clearly dose-related and were not observed in the other sex.

The LOAEL for AE C638206 in male and female rats was 2000 mg/kg, based
on the transient effect of lower body temperature.  The NOAEL for male
and female rats was 100 mg/kg.

This neurotoxicity study is classified as Acceptable/Guideline, and
satisfies the guideline

requirement for an acute neurotoxicity study in rats (870.6200; OECD
424) provided positive

control neuropathology data are submitted by the conducting laboratory.

	870.6200 Subchronic Neurotoxicity Screening Battery

In a subchronic neurotoxicity study (MRID 46474221), Technical Grade AE
C638206 (97.8% a.i., Batch # OP2050046) was administered to 10 CD
rats/sex at dietary concentrations of 0, 200, 1400, or 10,000 ppm for 13
weeks.  Time-weighted average doses were 0, 15.0, 106.6, or 780.6
mg/kg/day, respectively, for males and 0, 18.0, 125.2, or 865.8
mg/kg/day, respectively, for females.  Neurobehavioral assessment
(functional observational battery [FOB] and motor activity testing) was
performed on all animals pre-test and at weeks 4, 8, and 13.  At study
termination, 6 animals/sex/group were euthanized and perfused in situ
for neuropathological examination.  Of the perfused animals, control and
high-dose rats were subjected to histopathological evaluation of brain
and peripheral nervous system tissues.  Positive control data for FOB
and motor activity testing were submitted in MRID 46474222 and were
summarized in MRID 46474220.

All animals survived to scheduled sacrifice.  No treatment-related
clinical signs of toxicity or gross lesions were observed in any group.
FOB findings and motor activity were similar between the treated and
control groups.

Mean body weight of the low-dose males and females was similar to the
controls throughout the study.  Mid- and high-dose males and females had
slightly lower body weight than that of the control group beginning at
week 1 but these data were not analyzed statistically.  Overall body
weight gain by the high-dose males and females and mid-dose females was
81%, 72%, and 87% (p  0.05 or 0.01), respectively, of the respective
control levels.  The most pronounced effect on body weight gain in the
high-dose groups was during weeks 0-1 when males and females gained 56%
and 63%, respectively, of the control level.  Weight gain by the
mid-dose groups appeared to be consistently less than that of controls
at each weekly interval.  Food consumption by the high-dose males and
females was slightly less than that of the controls for most weekly
intervals of the study.  Excessive food scatter was observed by the mid-
and high-dose males and by all treated female groups.  Overall food
conversion efficiency by the high-dose males and females and mid-dose
females was 87%, 79%, and 89%, respectively, of the respective control
levels.  The most pronounced effect on food efficiency in the high dose
groups was during week 1 when males and females were 62% and 69%,
respectively, of the control level.

Treatment-related lesions observed in the liver (hypertrophy) of males
and females and the male kidney (hyaline droplets) were not considered
adverse or relevant to humans.

Therefore, the systemic and neurotoxicity LOAEL for AE C638206 in male
and female rats is 10,000 and 1400 ppm, respectively (780.6 and 125.2
mg/kg/day for males and females, respectively) based on decreased body
weight gain, food consumption, and food efficiency.  The NOAEL for males
and females was 1400 and 200 ppm, respectively (106.6 and 18.0 mg/kg/day
for males and females, respectively).

The study is classified as Acceptable/Guideline and does satisfy the
guideline requirement for a subchronic neurotoxicity study in rats
(870.6200b) provided positive control neuropathology data are submitted
by the conducting laboratory.

	870.6300 Developmental Neurotoxicity Study

Not required for this chemical.

A.3.8	Metabolism

	870.7485	Metabolism - Rat

Five studies (MRIDs 46474226, 46474239, 46474241, 46474242, and
46474244) were conducted to examine the metabolism and disposition of AE
C638206 (fluopicolide) in male and female Sprague-Dawley CD rats
following single doses of [14C-2,6-pyridyl]-AE C638206 at 10 mg/kg bw or
[14C-2,6-pyridyl]-AE C538206 and [14C-U-phenyl]-AE C638206 at 10 and 100
mg/kg bw.  Rats were subjected to the dosing regimens above using
[14C-2,6-pyridyl]-AE C538206 (lot nos. 903AE-3 and GAR 2034-/4; >99% and
97% radiochemical purity) or [14C-U-phenyl]-AE C538206 (lot no. CFQ
12747; 99.1% radiochemical purity) and nonlabeled test article (batch
no. R001737, 99.3% chemical purity).  Excretion, tissue distribution,
pharmacokinetics (blood/plasma), and metabolite profiles were
determined.  In MRID 46474242, metabolite profiles were assessed in
urine and fecal extracts of male and female rats given a single oral 10
mg/kg bw dose of [14C-2,6-pyridyl]-AE C638206 and sacrificed at 48 hours
post-dosing.

There were no biologically significant treatment-related effects noted
during the course of the study.  Overall recovery of administered
radioactivity was an acceptable 93.9-103.6%.  The data supported the
contention that AE C538206 is readily absorbed and rapidly excreted
within 72 hours following a single oral dose of 10 mg/kg.  Fecal
elimination accounted for 68.8-72.4% of the administered radioactivity
whereas urinary excretion accounted for only 18.8-21.4% of the
administered radioactivity.  In the bile excretion study (MRID
46474244), 51.7% of the administered radioactive dose in both sexes was
excreted by the cannulated bile duct indicating a significant portion of
the radioactivity recovered in feces is derived from hepatic metabolism
of AE C638206.  Time-course blood/plasma and tissue studies revealed
rapid absorption and distribution of administered radioactivity to all
organs and tissues followed by moderately rapid excretion with reduction
to background levels in most tissues and organs within 72 hours.  Tissue
concentrations peaked at 6-7 hours post-dosing and about 96% of the peak
tissue concentrations were dissipated between 6-7 hours and 168 hours
post-dose.  Absorption and excretory patterns did not exhibit
gender-related variability, but blood/plasma kinetic studies (MRID
46474226) suggest near-saturation of absorption at the high dose (100
mg/kg bw).  Based upon tissue burden data, neither AE C638206 nor its
metabolites appear to undergo any significant tissue sequestration.
With the exception of transiently higher levels in the liver, kidneys,
and intestines during the elimination phase, radioactivity
concentrations in any given tissue consistently represented considerably
less than 1% of the administered dose within 24 hours of administration
of AE C638206.

Both urinary and fecal metabolites were quantified by HPLC and most were
identified using HPLC or HPLC/MS in conjunction with known standards.
The major metabolites identified appeared to be oxidative N-dealkylation
cleavage products.  Extraction efficiency appeared to be excellent and
most components in both of the matrices examined (urine and feces) were
adequately quantified and characterized.  The available data, based upon
studies using [14C-2,6-pyridyl]-AE C638206, affirmed the metabolism
pathway (Appendix, Figure 1) proposed by the investigators.

These metabolism studies (MRID 46474226, 46474239, 46474241, 46474242,
and 46474244) are, collectively, Acceptable/Guideline and satisfy the
requirements for a Metabolism and Pharmacokinetics Study
[OPPTS 870.7485 (§85-1)].  The studies were properly designed,
conducted and reported.

	870.7600	Dermal Absorption – Rat

In a dermal penetration study (MRID 46708638), [14C-Phenyl]-AE C638206
(Fluopicolide; 99.8% radiochemical purity; Batch No. SEL/1200) in a
commercial concentrate (or aqueous dilution of a concentrate for the low
dose) was applied to the skin of 5 male Sprague-Dawley rats/time
point/dose. The dose (1.43 or 659 μg/cm2 skin) was applied to 12 cm2
skin and removed after 8 hours.  The animals were sacrificed at 8, 24,
72, or 144 hours after application.  Additionally, 2 male rats/time
point/dose were treated similarly in a preliminary study and were
sacrificed at 24, 72, or 144 hours, except only 1 rat was treated with
the low dose in the 144 hour group.

Recovery of the applied dose was 91-109%.  The distribution profile of
radioactivity was qualitatively similar between the two dose groups.
The majority of the administered dose (41-69% of the low dose and 87-91%
of the high dose) was recovered from the swabs used to remove the test
compound from the skin after 8 hours of treatment.  A total of 56-81%
(low dose) or 92-95% (high dose) was considered not absorbed.  After 144
hours, only 2-7% remained at the dose site and was considered available
for absorption.  Estimates of dermal absorption were based on the sum of
urine + feces + cage wash + tissues + treated skin + stratum corneum.
Dermal absorption ranged from 3-8% (low dose) to 22-37% (high dose).  In
the main studies, dermal absorption was greatest at 24 hours after
application, but there was no clear evidence for increased dermal
absorption with time at either dose.  Although there was not a
time-dependent increase in total dermal absorption at either dose, there
was a time-dependent increase in absorption through the stratum corneum
at the low dose (but not the high dose).

This study is classified as acceptable/guideline and satisfies the
guideline requirements (OPPTS 870.7600; OECD none) for a dermal
penetration study in rats.

In a non-guideline in vitro dermal penetration study (MRID 46708637),
[14C-Phenyl]-AE C638206 (Fluopicolide; 99.8% radiochemical purity; Batch
No. SEL/1200) was applied to excised human and rat skin in a suspension
concentrate formulation (EXP 11120A) at 2 dose concentrations, 1.9 and
744 μg/cm2 skin.  Flow-through diffusion cells were prepared for each
skin type at each dose level (n=7/group).  Dermatomed membranes of
approximately 300 µm thickness were tested for permeability prior to
treatment.  Receptor fluid samples were collected each hour after
treatment for 24 hours.  At 8 hours after test compound application, the
skin was swabbed with a mild detergent solution.  After 24 hours, the
experiment was terminated, and the skin membranes were tape stripped.
The initial 2 tape strips were assumed to represent the residual
(non-absorbed) dose.  Subsequent tape strips, the remaining skin, and
the receptor fluid remaining in the cell and outlet tubing at the end of
the experiment were also assayed.  Radioactivity was determined by
liquid scintillation counting.  Results for 5-7 skin
samples/species/dose were reported.

Total recovery was 92.3-96.5%.  The total amounts of applied
radioactivity absorbed within 24 hours at the high dose level were
0.022% in humans and 0.172% in rats, while at low dose levels the
amounts absorbed were 1.454% in humans and 14.26% in rats.  Therefore,
the amount of radioactive material absorbed was 7.8 times greater for
rat skin than for human skin at the high dose level, and 9.8 times
greater for rat skin than human skin at the low dose level.  These data
indicate that dermal penetration studies in the rat will provide a very
conservative estimate of dermal absorption in humans for risk
assessment.

This study is acceptable/non-guideline.

A.3.9	Special/Other Studies

	None.

Appendix B:  Metabolism Assessment

  TC \l1 "Appendix B:  Metabolism Assessment

Table B.	Tabular Summary of Fluopicolide and its Metabolites and
Degradates in Plants

Chemical Name (other names in parenthesis)

Matrix	Percent TRR (PPM) 1	Structure

Matrices - Major Residue, >10%TRR	Matrices - Minor Residue, <10%TRR

	Parent fluopicolide

2,6-dichloro-N-[[3-chloro-5-(trifluoromethyl)-2-pyridinyl]methyl]-benzam
ide

(AE C638206)	Grapes (fruit)	91.2 %

(1.152 ppm)

(phenyl label)

87.4%

(0.910 ppm)

(pyridinyl label)

Metabolite  1:

2,6-dichlorobenzamide

(BAM)

(AE C653711)	Grapes (fruit)

2.0%

(0.026 ppm)

(phenyl label only)

Metabolite 2:

3-chloro-5-trifluoromethylpyridine-2-carboxylic acid

(PCA)

(AE C657188)	Grapes (fruit)

2.3%

(0.024 ppm)

(pyridinyl label only)

Metabolite 3:

2,6-dichloro-N-[(3-chloro-5-trifluoromethylpyridin-2-yl)methyl]-3-hydrox
ybenzamide

(AE C643890)	Grapes (fruit)

0.2%

(0.002 ppm)

(phenyl label only)

Grapes: MRID 46474025; three foliar applications for a total seasonal
rate of 0.357 lb ai/A (1x); 21-day PHI

Appendix C:  Tolerance Assessment Summary and Table  TC \l1 "Appendix
C:  Tolerance Assessment Summary and Table

HED has determined that the terminal residue of concern in grape for the
tolerance expression is fluopicolide per se
[2,6-dichloro-N-[[3-chloro-5-(trifluoromethyl)-2-pyridinyl]methyl]benzam
ide].  The tolerance expression (fluopicolide) proposed in the petition
is appropriate.

No Codex, Canadian, or Mexican maximum residue limits (MRLs) or
tolerances have been established for fluopicolide.

Adequate field trial data for grapes are available.  The available field
trial data will support a tolerance for fluopicolide in/on grape of 2.0
ppm.

Adequate processing data for raisins are available pending submission of
the requested storage stability data/information.  The available data
indicate that residues of fluopicolide are not likely to concentrate in
juice but do concentrate in raisins.  The processing data indicate that
a tolerance of 6.0 ppm for grape, raisin is appropriate.

The proposed tolerances should be revised to reflect the recommended
tolerance levels and correct commodity definitions as specified in Table
C.

Table C.   Tolerance Summary for Fluopicolide on Imported Grapes.

Commodity	Proposed Tolerance (ppm)	Recommended Tolerance (ppm)	Comments;
Correct Commodity Definition

Grape (imported)	2	2.0	Grape

Grape, raisin (imported)	6	6.0	Grape, raisin

Appendix D:  Review of Human Research TC \l1 "Appendix D:  Review of
Human Research

None.

Appendix E: 	Sections 3.0, 4.0, 8.0, and 10.0 for BAM (from R. Mitkus,
RAB1, updated 7/27/06)  TC \l1 "Appendix E:  Sections 3.0, 4.0, 8.0, and
10.0 for BAM

3.0	 	Hazard Characterization/Assessment

3.1	 	Hazard and Dose-Response Characterization

Studies Considered in the Toxicity and Dose-Response Evaluation

Dichlobenil

Data from the following studies were used to evaluate the hazard
potential of dichlobenil:

Acute (for olfactory toxicity): one intraperitoneal (single dose)
toxicity study (mouse, rat) and one subcutaneous (single dose,
neonates)/intraperitoneal (single dose, adults) toxicity study (mouse)

Subchronic: Two oral (hamster, rat), one dermal (rabbit), one dermal
(mouse), and two inhalation (rat) toxicity studies

Chronic: Two oral toxicity (dog), two oral carcinogenicity (hamster),
and one combined oral toxicity/carcinogenicity (rat) studies

Reproduction/developmental: Two developmental (rat, rabbit) and one
two-generation reproduction (rat) studies

Other: Nine genotoxicity screens (in vivo/in vitro) and five
metabolism/toxicokinetics studies (rat)

BAM

Data from the following studies were used to evaluate the hazard
potential of dichlobenil:

Acute (for olfactory toxicity): one intraperitoneal (single dose)
olfactory toxicity study (mouse)

Subchronic: One oral (rat) toxicity study

Chronic: One oral toxicity (dog) study and one combined oral
toxicity/carcinogenicity (rat) study

Reproduction/developmental: One developmental (rabbit) toxicity study
and one three-generation reproduction (rat) study

Other: Three genotoxicity screens (in vivo/in vitro)

3.1.2		Sufficiency of studies/data

Dichlobenil

The acute and chronic studies were sufficient to determine whether human
hazard

could exist within the context of dose, duration, timing, and route of
exposure.  Data

quality is acceptable.  There was no evidence that dichlobenil was
either

mutagenic or clastogenic in either in vitro or in vivo assays.
Dichlobenil was determined

to be non-mutagenic in bacteria and mouse lymphoma cells, negative in an
in vivo

chromosomal aberration assay, and did not cause unscheduled DNA
synthesis (repair of

DNA damage) in or transformation of mammalian cells in vitro.  The HED
Cancer Peer

Review Committee (1995) classified dichlobenil as a “Group C, possible
human

carcinogen.”  An RfD approach was recommended for the quantification
of human

cancer risk.

Based on olfactory toxicity observed following dermal (Deamer et al.
1994), inhalation

(Guideline study), and intraperitoneal (i.p.) (Brandt et al. 1990;
Eriksson and

Britebo 1995) exposures of adult animals and subcutaneous exposure
(s.c.) of neonatal

mice (Eriksson and Brittebo 1995), the Agency requires a comparative
study of

olfactory toxicity by the oral route in neonates and adults.  The
registrant is

encouraged to consult with the Agency to discuss the protocol.

BAM

The acute and chronic studies were sufficient to evaluate human hazard
potential, and

data quality is acceptable. There was no evidence that BAM was either
mutagenic or

clastogenic in either in vitro or in vivo assays.  In addition, BAM did
not cause

unscheduled DNA synthesis (repair of DNA damage) in mammalian cells in
vitro.

The carcinogenic potential of BAM was evaluated in the rat.  An
increased incidence of hepatocellular adenomas was observed at the high
dose in females only in the study.  However, the statistical
significance of the effect was marginal (P=0.049), dosing was considered
adequate in the study, and the tumors were non-cancerous.  In the
absence of data for a second species, HED considers the carcinogenic
potential of BAM to be similar to that of the parent compound,
dichlobenil (possible human carcinogen).

BAM-mediated olfactory toxicity was observed in one study (i.p.)
collected from the open literature (Brittebo et al. 1991).  However,
olfactory epithelial necrosis was observed in adult animals at a dose
that was eight times higher than that which caused the same effect using
dichlobenil.  In the absence of studies via other routes of exposure,
potential BAM-mediated olfactory toxicity in offspring is considered by
HED to be similar to that of dichlobenil.

3.1.3 		Herbicidal Mode of Action

Dichlobenil is a systemic herbicide that inhibits cellulose biosynthesis
in plants, thereby leading to alteration of cell wall structure and
function (Sabba et al. 1999).  Dichlobenil is primarily converted to
2,6-dichlorobenzamide (BAM) in the soil by way of microbial degradation
and is then taken up by the roots of exposed plants (Verloop 1972).

3.1.4		Mammalian Toxicology

<IP_ADDRESS>		Dichlobenil

Dichlobenil technical demonstrated moderate acute toxicity (Category II
or III) via the oral, dermal, and inhalation routes.  It is neither a
dermal irritant (Category IV), eye irritant (Category IV), nor a dermal
sensitizer (Table 3.1a).

A summary of the subchronic and chronic toxicity and genotoxicity
databases for dichlobenil is found in Table 3.1b.  In the subchronic and
chronic oral toxicity studies in hamsters, rats, and dogs, liver
toxicity was the adverse effect most often observed at the LOAEL.  For
example, in a 90-day oral toxicity study in rats, inflammation and
necrosis were observed in the liver of males, and increased liver weight
and liver histopathology (swelling and vacuolation of hepatocytes) were
observed in females.  In a 90-day oral toxicity study in hamsters,
increased liver weight, enlarged liver (with rough surface), and swollen
hepatocytes were observed in females.  In addition, decreased weight of
the prostate and mineralization of the prostate were reported in males.
Increased liver weights and hepatic enzymes, as well as liver
histopathology, were observed at lower doses in both chronic dog
toxicity studies, as well as in the combined chronic
toxicity/carcinogenicity study in the rat.

In addition to the liver, the nose is considered a target organ for
dichlobenil.  Olfactory toxicity was observed in short-term dermal and
inhalation toxicity studies in mice and rats.  Because olfactory
toxicity was not assayed following acute or subchronic oral exposure to
dichlobenil, the absence of this information is considered a data gap.
Olfactory toxicity was not observed in the chronic oral (capsule)
toxicity study in the dog.

In a high-dose carcinogenicity study in the hamster, decreased body
weight gain was observed in males and females, while liver
histopathology (finely vacuolated hepatocytes, hepatitis, and brown
pigment in the hepatocytes) was observed in males.  According to the
Health Effects Division 2nd Carcinogenicity Peer Review (1995), there
was a treatment-related increase in liver adenomas and combined
adenomas/carcinomas in males only at the highest dose tested, when
compared to controls.  However, dosing was considered excessive at this
dose in both sexes, based on decreased body weight gains and severe
hepatotoxicity.

In a second carcinogenicity study performed in hamsters at lower doses,
reduced secretion of the prostate and seminal vesicles was observed at
the LOAEL in males, whereas generalized systemic toxicity was observed
in females, as evidenced by decreased body weight gain, peritonitis, and
hyperplasia of the adrenal cortex, small intestine, and bone marrow
(sternum).  According to the Health Effects Division 2nd Carcinogenicity
Peer Review (1995), there was no treatment-related increase in the
incidence of any tumor type in this study.  Dosing was considered
adequate, based on decreased body weight gains and hyperplasia in
various tissues in both sexes.

In a combined chronic toxicity/carcinogenicity study in the rat, adverse
effects on clinical chemistry, gross pathology, and histopathology
confirmed dichlobenil hepatotoxicty. Nephrosis (kidney damage) was also
observed in males, followed by parathyroid hyperplasia, which was
considered a compensatory mechanism to maintain normal blood calcium
levels.  According to the Health Effects Division 2nd Carcinogenicity
Peer Review (1995), a treatment-related increase in the incidence of
hepatocellular adenomas and combined adenomas/carcinomas was observed in
females only at the highest dose tested.  Dosing was considered adequate
in females, but excessive in males, at this dose.  Based on the weight
of the evidence, the HED 2nd Carcinogenicity Peer Review (1995)
classified dichlobenil as a Group C, possible human carcinogen, and
recommended that an RfD approach should be used for quantification of
human cancer risk.

Olfactory toxicity was observed following dermal and inhalation
exposures in three

toxicity studies that were either published in the open literature (one
dermal) or submitted to the Agency (two inhalation).  In each study,
degeneration of the olfactory epithelium was observed.  Since the
olfactory epithelium is composed of olfactory sensory neurons, damage to
the olfactory epithelium is considered a neurotoxic effect that is
confined to this organ only.

HED concluded that there was no evidence of increased susceptibility to
offspring

following pre-natal exposure to rats or rabbits in developmental
toxicity studies.

Evidence of increased pre-/post-natal susceptibility was observed in the
two-generation

reproduction study in rats.  However, the degree of concern for this
susceptibility is low,

since the NOAEL from this study is six times lower than the dose (LOAEL)
at which

adverse effects (decreased pup body weight) were observed, and is
therefore protective.

Delayed maturity of the uterus was observed in all high-dose females
tested in the chronic oral (capsule) toxicity study in the dog.  A
marked decrease in mean uterine weight at the high dose confirmed this
finding.  Ovarian weights were also decreased in high-dose females, but
no alterations were observed microscopically.  These results are
suggestive of modulation of the female endocrine system in this study;
however, the dose utilized in this risk assessment for the chronic RfD
is almost forty times lower than that at which the effects were observed
and is considered protective of any potential endocrine modulation.

Table 3.1a.  Acute toxicity profile for dichlobenil technicala

Guideline No./Study Type

MRID No.

Results	Toxicity Category

870.1100/Acute oral toxicity (rat)	44866902	>2000 mg/kg	III

870.1200/Acute dermal toxicity (rabbit)	43250401	<2000 mg/kg	II

870.1300/Acute inhalation toxicity (rat)	40425401

>0.250 mg/L	II

870.2400/Primary eye irritation (rabbit)	40425403	Not an eye irritant	IV

870.2500/Primary dermal irritation (rabbit)	40425402

Not a dermal irritant	IV

870.2600/Dermal sensitization (guinea pig)	40548501	Not a skin
sensitizer	---

a Based on Memo, Dupuy JL, D257750, 11/12/1999

Table 3.1b.  SUBCHRONIC, CHRONIC, AND GENO- TOXICITY PROFILE FOR
DICHLOBENIL TECHNICAL

Guideline No./

Study Type

MRID No. (Year)/Doses/ Classification

Results

870.3100

90-day oral (hamster; dietary)

40600701 (1987)

0, 41, 209, 1289, or 7500/4648 ppm (adjusted due to evaporation;
equivalent to 0, 3, 16, 79, or 395/263 mg/kg bw/day)

Acceptable/Non-guideline

NOAEL = 3 (M) and 16 (F) mg/kg/day

LOAEL = 16 mg/kg/day (M) based on decreased weight of the prostate and
mineralization of the prostate; and 79 mg/kg/day (F) based on increased
liver weight, enlarged liver (with rough surface), and swollen
hepatocytes

870.3100

90-day oral (rat; dietary)

00107106 (1961)

0, 100, 1000, 3000, or 10000 ppm (equivalent to 0, 4.5, 45, 135, or 453
mg/kg/day; adjusted for purity)

Acceptable/Non-guideline

NOAEL = 4.5 (M) and 45 (F) mg/kg/day

LOAEL = 45 mg/kg/day (M) based on hepatocytic inflammation and necrosis;
and 135 mg/kg/day (F) based on increased liver weight and liver
histopathology (swelling and vacuolation of hepatocytes)

870.3200

21-day dermal

(rabbits)

43879301 (1995)

0, 100, 300, or 1000 mg/kg/day

Acceptable/Non-guideline

NOAEL = 1000 mg/kg/day (HDT)

LOAEL was not observed.

Non-guideline (literature)

5-day dermal (mouse)

Deamer et al. (1994); no MRID

0, 10, 25, 50, 100, 150, or 200 mg/kg/day

Acceptable/Non-guideline

NOAEL = 25 mg/kg/day

LOAEL = 50 mg/kg/day based on olfactory epithelial damage following
single (1-day) and repeated (5-day) dosing

870.3465

90-day inhalation (rat)

46398701 (2002), 46653001 (2002)

0, 2.3, 5.1, or 12 mg/m3 (equivalent to 0, 0.03, 0.07, or 0.17
mg/kg/day, respectively)

for 28 days (6 hrs/day; 5 days/week)

Unacceptable/Guideline due to inadequate dosing for 28 days

NOAEL (28 days) = 12 mg/m3 (HDT)

LOAEL (28 days) was not observed.

870.3465

90-day inhalation (rat)	46653001 (2002)

0, 21, 77, or 200 mg/m3 (equivalent to 0, 0.3, 1.1, or 2.9 mg/kg/day,
respectively  )

for 7 days (range finding; 6 hrs/day)

Acceptable/Non-guideline

NOAEL (7 days, range finding) was not observed.

LOAEL (7 days, range finding) = 21 mg/m3 (0.3 mg/kg/day) based on an
increased incidence of nasal degeneration

870.4100

Chronic toxicity oral (dog; dietary)

00067649 (1969)

0, 20, 50, or 350 ppm (equal to 0, 0.5, 1.25, or 8.75 mg/kg/day)

Acceptable/Non-guideline

NOAEL = 1.25 mg/kg/day

LOAEL = 8.75 mg/kg/day based on increased liver weight (M&F), serum
alkaline phosphatase (M&F), and serum alanine aminotransferase (F);
liver histopathology [leukocytic infiltration around the central veins
(M&F) and necrosis (M)]; and an increase in the number of erythrocytes
in the urine (F)

870.4100

Chronic toxicity oral (dog; capsule)

43969701 (1995)

0, 1, 6, or 36 mg/kg/day

Acceptable/Guideline

NOAEL = 1 mg/kg/day

-GT and periportal hypertrophy of hepatocytes (M)

870.4200

Carcinogenicity oral (hamster; dietary)

41988301 (1991), 42015101 (1991), 42563601 (1992)

0, 5, 26, 132, or 675 ppm [equal to 0/0, 0.34/0.35, 1.69/1.78,
9.39/9.20, or 45.64/48.85 mg/kg/day (M/F)]

Acceptable/Non-guideline

NOAEL = 1.69 (M) and 9.20 (F) mg/kg/day

LOAEL = 9.39 mg/kg/day (M) based on reduced secretion of the prostate
and seminal vesicles; and 48.85 mg/kg/day (F) based decreased body
weight gain, peritonitis, and hyperplasia of the adrenal cortex, small
intestine, and bone marrow (sternum)

No evidence of carcinogenicity.

870.4200

Carcinogenicity oral (hamster; dietary)

42221201 (1992), 42563601 (1992)

0, 675, 1500, or 3375 ppm [equal to 0/0, 51/55, 117/121, 277/277
mg/kg/day (M/F)]

Acceptable/Non-guideline

NOAEL was not observed.

LOAEL = 51/55 mg/kg/day (M/F) based on decreased body weight gain (M&F),
and liver histopathology (finely vacuolated hepatocytes, hepatitis, and
brown pigment in the hepatocytes) (M)

Statistically significant increase in hepatocellular adenomas and
combined adenomas/carcinomas at 277 mg/kg/day (M); dosing considered
excessive in M&F

870.4300

Combined Chronic Toxicity/

Carcinogenicity oral (rat; dietary)

00147438 (1983), 40401101 (1987), 40823801 (1988)

0, 50, 400, or 3200 ppm (equal to 0, 2.3, 18.9, or 173.1 mg/kg/day)

Acceptable/Non-guideline

NOAEL = 2.3 mg/kg/day

LOAEL = 18.9 mg/kg/day based on changes in clinical chemistry (increased
blood urea nitrogen, cholesterol), gross pathology (enlarged liver,
enlarged kidney), and histopathology (nephrosis, parathyroid
hyperplasia) in males; and increased liver weight, enlarged liver, and
cytologic alterations (polyploidy with hepatocytic swelling) in the
liver in females.

Statistically significant increase in hepatocellular adenomas and
combined adenomas/carcinomas in at 173.1 mg/kg/day (F); dosing
considered adequate in females

Statistically significant increasing trend for hepatocellular adenomas,
carcinomas, and combined adenomas/carcinomas at 173.1 mg/kg/day (M);
dosing considered excessive in males

870.3700

Developmental toxicity oral (rat; gavage)

00147437 (1984)

0, 20, 60, or 180 mg/kg/day

Acceptable/Non-guideline

Maternal NOAEL = 20 mg/kg/day

Maternal LOAEL = 60 mg/kg/day based on decreased body weight gain, food
consumption, and food efficiency during dosing

Developmental  NOAEL = 180 mg/kg/day

Developmental LOAEL was not identified.

870.3700

Developmental toxicity oral (rabbit; gavage)

41257302 (1989)

0, 15, 45, or 135 mg/kg/day

Acceptable/Non-guideline

Maternal NOAEL = 45 mg/kg/day

Maternal LOAEL = 135 mg/kg/day based on decreased body weight gain and
food consumption during dosing

Developmental  NOAEL = 45 mg/kg/day

Developmental LOAEL = 135 mg/kg/day, based on increased

number of total resorptions/dam and post-implantation loss;

and increased incidences of fetal external (cleft palate,

adactyly, bilateral open eye), visceral (abnormal cystic

gallbladder, distended ureter with bilateral severe

hydronephrosis), and skeletal (malformed and malpositioned

right scapula, right radius absent with malpositioned ulna and

humerus, fused cervical vertebral arches, asymmetrically

ossified and fused cervical vertebra centra, abnormally

shaped cranium with enlarged and misshapen fontanelle,

enlarged fontanelle, misshapen frontals, skull and frontals

foreshortened and nasal malpositioned, and major fusion of

sternebrae) anomalies

870.3800

2-generation reproduction oral (rat; dietary)

	41257303 (1989), 42239101 (1992)

0, 60, 350, or 2000 ppm (equivalent to 0, 3, 17.5, or 100 mg/kg/day)

Acceptable/Non-guideline	Parental NOAEL = 17.5 mg/kg/day

Parental LOAEL = 100 mg/kg/day based on decreased body weight gains
during premating (M&F) and gestation (F) in both generations and
decreased food consumption during premating in both generations (M&F)

Reproductive NOAEL = 17.5 mg/kg/day

Reproductive LOAEL = 100 mg/kg/day based on decreased number of
implantations/dam in F1 (unreported for P)

Offspring NOAEL = 3 mg/kg/day

Offspring LOAEL = 17.5 mg/kg/day based on decreased body weight during
weaning in both generations

Non-guideline (literature)

Fetal and neonatal mouse olfactory study (single injections; s.c. in
neonates, i.p. in adults)	Eriksson and Brittebo (1995); no MRID

0, 12, or 25 mg/kg/day (s.c. in neonates, i.p. in adults)

Acceptable/Non-guideline	Parental NOAEL not observed.

Parental LOAEL (i.p.) = 12 mg/kg/day based on many vacuolated,
degenerated, or necrotic Bowman’s glands and no periodic acid-Schiff
(PAS) staining of contents of Bowman’s glands

Offspring NOAEL not observed.

Offspring LOAEL (PND 8; s.c.) = 12 mg/kg/day based on no periodic
acid-Schiff (PAS) staining of contents of Bowman’s glands (measure of
mucus production)

Non-guideline (literature)

Adult mouse olfactory study (single injection; i.p.)	Brandt et al.
(1990); no MRID

0, 6, 12, 25, or 50 mg/kg/day (i.p.)

Acceptable/Non-guideline	NOAEL (i.p.) = 6 mg/kg/day

LOAEL (i.p.) = 12 mg/kg/day based on necrosis in Bowman’s glands and
olfactory epithelium

870.5100

In vitro bacterial reverse mutation (Ames test)

00153579 (1984)

g/plate (-/+ activation) in S. typhimurium

Acceptable/Guideline

Negative with or without activation.

870.5100

In vitro bacterial reverse mutation (Ames test)

00153586 (1981)

At concentrations up to 5000 g/plate (-/+ activation) in E. coli and
S. typhimurium; and 5000 g/disk (- activation) in B. subtilis

Acceptable/Guideline

Negative with or without activation.

870.5300

In vitro mouse lymphoma (L5178Y) mutation

00153576 (1984)

At concentrations up to 280 g/ml (- activation) and 50 g/ml (+
activation)

Acceptable/Guideline

Negative with or without activation.

870.5395

In vivo mouse erythrocyte micronucleus assay

00153578 (1983)

0, 300, 600, or 1200 mg/kg

Unacceptable/Guideline due to insufficient sampling times

Negative.

870.5375

In vitro chromosomal aberrations (human lymphocytes)

00153577 (1984)

g/ml (-/+ activation) (limit of solubility)

Acceptable/Guideline

Negative with or without activation.

870.5375

In vitro chromosomal aberrations (CHO cells)

43191501 (1990)

At concentrations up to 100 g/ml (-/+ activation)

Acceptable/Guideline

Negative with or without activation.

870.5550

In vitro Unscheduled DNA synthesis (human HeLa epithelioid cells)

00153580 (1984)

At concentrations up to 102.4 g/ml (-/+ activation)

Acceptable/Guideline

Negative with or without activation.

In vitro transformation assay (BALB/3T3 cells)

00153581 (1984)

At concentrations up to 7500 g/ml (+ activation)

Acceptable/Guideline

Negative.

In vitro recombination assay

00153586 (1981)

At concentrations up to 5000 g/disk (- activation) in B. subtilis

Acceptable/Non-guideline

Negative.

870.7485

Metabolism and toxicokinetics

(rats)	41227401-04 (1989), 41299401 (1987)

2.5 mg/kg (single dose; oral); 5 mg/kg (single dose; oral, i.v.); 3.75,
30, or 240 mg/kg (single and repeated dose; oral)

Acceptable/Guideline	After 7 days of i.v. exposure, 65-71% and 25-31% of
the dose was excreted in the urine and feces, resp., in M&F; similar
results were obtained for the oral route of exposure (therefore
efficient GI absorption).  79% and 20% oral dose was measured in bile
and urine, resp., 24 hrs. after exposure; 20-30% oral dose eliminated in
feces via bile (supports enterohepatic recirculation).  95% of urinary
metabolites were excreted 24 hrs. after dosing.  Recovery (96%) 7 days
after a single i.v. dose indicates low residence time in tissues;
slightly longer residence time following oral exposure is suggested by
84-86% recovery 7 days after a single oral dose. Tissue levels peaked
1-3 hrs. after oral dosing.  Dichlobenil is metabolized via
hydroxylation at the 3 or 4 position of the phenyl group followed by
sulfation or glucuronidation; or via displacement of a Cl atom followed
by glutathione conjugation. Glutathione conjugation appears to be
saturable during repeated dosing.

<IP_ADDRESS>		2,6-Dichlorobenzamide (BAM)

The dichlobenil soil metabolite, 2,6-dichlorobenzonitrile (BAM)
demonstrated moderate acute toxicity (Category III) via the oral route
of exposure (Table 3.1c).  Because the subchronic and chronic toxicity
of BAM is less than or equal to that of dichlobenil (parent compound),
the acute toxicity of BAM via the inhalation and dermal routes is
expected to be less than or equal to that of dichlobenil.

A summary of the subchronic and chronic toxicity and genotoxicity
databases for BAM is found in Table 3.1d.  In the subchronic and chronic
oral toxicity studies in the rat and dog, respectively, body weight
change was the toxicological effect most often observed at the LOAEL.
In the combined chronic toxicity/carcinogenicity study in the rat,
toxicologically significant changes in body weight were also observed at
the LOAEL, as were eosinophilic foci in the liver.  In general, adverse
liver effects were observed in the submitted studies at doses of BAM
that were higher than those of dichlobenil (parent).

There was no evidence of carcinogenicity in the combined chronic
toxicity/carcinogenicity study of BAM in the rat.  An increased
incidence of hepatocellular adenomas was observed at the high dose in
females only in the study.  However, the statistical significance of the
effect was marginal (P=0.049), dosing was considered adequate in the
study, and the tumors were non-cancerous.  In addition, there was no
evidence that BAM was either mutagenic or clastogenic.  However, in the
absence of a second species, HED considers the carcinogenic potential of
BAM to be similar to that of dichlobenil (possible human carcinogen) and
that it is appropriate to use an RfD approach for quantification of
human cancer risk.

BAM-mediated olfactory toxicity was observed in one study collected from
the open literature (Brittebo et al. 1991).  Although olfactory
epithelial necrosis was observed after i.p. administration of BAM, the
dose was eight times higher than that which caused the same effect using
dichlobenil.  In the absence of studies via other routes of exposure,
BAM-mediated olfactory toxicity is considered by HED to be less than
that of dichlobenil (parent).

HED concluded that there was no evidence of increased susceptibility to
offspring following pre-natal exposure to rabbits in a developmental
toxicity study and pre-/post-natal exposure in the two-generation
reproduction study in the rat.

BAM is considered neurotoxic.  Toxicity to the olfactory sensory neurons
was observed following single i.p. exposures of mice to BAM (Brittebo et
al. 1991).  In the 90-day oral toxicity study in rats, reduced muscle
tone was observed; however, the toxicological significance of this
finding is unclear, given the lack of reproducibility of the effect in
other studies, the age of the study itself (1967), and the fact that the
purity of the compound was not reported in the study.  Lethargy and
ataxia were observed in mice tested orally in a dose-range finding study
for the in vivo erythrocyte micronucleus assay.  The effects were
resolved after 24 hours.  In addition, in a two-week dietary study
recently submitted and not fully reviewed by the Agency (MRID 46892401),
clinical signs of toxicity (slightly decreased muscle tone, slight loss
of pinnae reflexes) were observed in mice at 2500 ppm (approximately
equal to 375 mg/kg/day).  Therefore, HED is requesting Guideline acute
and subchronic neurotoxicity screening batteries (OPPTS 870.6200) with
BAM.

Table 3.1c.  Acute toxicity profile for soil metabolite
2,6-dichlorobenzamide (BAM)a

Guideline No./Study Type

MRID No.

Results	Toxicity Category

870.1100/Acute oral toxicity (mouse)	42940201

1538/1144 mg/kg (M/F)	III

a According to Reregistration Eligibility Decision (1998)

Table 3.1d.  SUBCHRONIC, CHRONIC, AND GENO- TOXICITY PROFILE FOR
METABOLITE, 2,6-DICHLOROBENZAMIDE (BAM)

Guideline No./

Study Type

MRID No. (Year)/Doses/ Classification

Results

870.3100

90-day oral (rat; dietary)

00067654 (1967)

0, 50, 180, 600, or 2300 ppm (equal to 0, 4, 14, 49, or 172 mg/kg/day)

Acceptable/Non-guideline

NOAEL = 14 mg/kg/day

LOAEL = 49 mg/kg/day based on decreased body weight gain (M) and reduced
skeletal muscle tone (day 4 only in males; days 91 and 92 only in
females)

870.3150

90-day oral (dog; dietary)

00067655 (1967)

0, 100, 300, or 2000 ppm (equal to 0, 7.5, 22.5, or 150 mg/kg/day)

Unacceptable/Guideline due to parasitic infections (ascariasis) in most
animals

NOAEL = 22.5 mg/kg/day

LOAEL = 150 mg/kg/day based on clinical signs (thin appearance, dull
coat, hair loss) and increased liver weight and serum alkaline
phosphatase concentrations (F) and clinical signs (thin appearance, dull
coat, hair loss) (M)

870.4700

Chronic toxicity oral (dogs; dietary)

42940203 (1971)

0, 60, 100, 180, or 500 ppm (equal to 0, 1.5, 2.5, 4.5, or 12.5
mg/kg/day)

Acceptable/Non-guideline

NOAEL = 4.5 mg/kg/day

LOAEL = 12.5 mg/kg/day based on decreased body weight and body weight
gain

870.4300

Combined Chronic Toxicity/ Carcinogenicity oral (rat; dietary)

42940202 (1971), 44043601 (1996), 44052901 (1996)

0, 60, 100, 180, or 500 ppm [equal to 0, 2.2/2.8, 3.6/4.7, 6.5/8.5, or
19/25 mg/kg/day (M/F)]

Acceptable/Non-guideline

NOAEL = 6.5 (M) and 4.7 mg/kg/day (F)

LOAEL = 19 mg/kg/day (M) and 8.5 mg/kg/day (F) based on decreased body
weight and body weight gain (≥ week 26) and an increased incidence of
hepatocellular alteration (eosinophilic foci)

Borderline statistically significant (P=0.049) increased incidence of
hepatocellular adenomas at 25 mg/kg/day (F only); dosing considered
adequate (M&F)

870.3700

Developmental toxicity oral (rabbit; gavage)

43003601 (1986), 43265201 (1994)

0, 10, 30, or 90 mg/kg/day

Acceptable/Guideline

Maternal NOAEL= 30 mg/kg/day

Maternal LOAEL= 90 mg/kg/day based on increased incidences of clinical
signs (late abortion, thin appearance) and decreased (severe) body
weight gain and food consumption during dosing

Developmental NOAEL = 30 mg/kg/day

Developmental LOAEL = 90 mg/kg/day based on increased

incidences of late abortion and skeletal (bipartite interparietal

bone) and visceral (postcaval lung lobe agenesis) anomalies

870.3800

3-generation reproduction oral (rat; dietary)

	42940204 (1971)

0, 60, 100, or 180 ppm (equivalent 0, 4.5, 7.5, or 13.5 mg/kg/day)

Acceptable/Non-guideline	Parental NOAEL = 13.5 mg/kg/day

Parental LOAEL was not observed.

Reproductive NOAEL = 13.5 mg/kg/day

Reproductive LOAEL was not observed.

Offspring NOAEL = 13.5 mg/kg/day

Offspring LOAEL was not observed.

Non-guideline (literature)

Adult mouse olfactory study (single injection; i.p.)	Brittebo et al.
(1991); no MRID

0, 25, 50, or 100 mg/kg/day (i.p.)

Acceptable/Non-guideline	NOAEL (i.p.) not observed.

LOAEL (i.p.) = 25 mg/kg/day based on decreased periodic acid-Schiff
(PAS) staining of contents of Bowman’s glands (measure of mucus
production)

Necrosis of Bowman’s glands and olfactory epithelium observed at 100
mg/kg/day only

870.5100

In vitro bacterial reverse mutation (Ames test)

43003603 (1992)

g/plate (-/+ activation) in S. typhimurium

Acceptable/Guideline

Negative with or without activation.

870.5395

In vivo mouse erythrocyte micronucleus assay

43003602 (1993), 43747101 (1995)

0, 250 mg/kg

Acceptable/Guideline

Negative.

Lethargy observed in dose-range finding (pilot) study at 100 mg/kg/day
(=LOAEL; NOAEL not observed)

870.5550

In vitro Unscheduled DNA synthesis (rat hepatocytes)

43003604 (1993)

At concentrations up to 1000 g/ml

Acceptable/Guideline

Negative.

3.2		Absorption, Distribution, Metabolism, Excretion (ADME)

The metabolism of [phenyl-U14C]dichlobenil was studied in male and
female Sprague-Dawley rats.  Following oral administration of
dichlobenil at 2.5 or 5 mg/kg, approximately 65-75% of the dose was
eliminated in the urine and 20-30% in the feces (via biliary excretion)
after seven days.  There were no apparent differences between the sexes.
 Results from oral, intravenous, and biliary excretion studies indicated
that the compound is readily absorbed from the gastrointestinal tract
and eliminated in the bile.  However, as a result of enterohepatic
recirculation, the compound is reabsorbed and then eliminated primarily
in the urine.  Based on elimination patterns, it was concluded that
animals dosed at 3.75, 30, or 240 mg/kg exhibited reduced absorption at
the high dose (i.e., saturation).  Specifically, the relative rate of
urinary excretion varied inversely with dose level, and increased
amounts of unchanged parent compound were excreted in the feces at high
doses.  No apparent sex-related differences were seen.  Similar
elimination patterns were noted following the administration of
[phenyl-U14C]dichlobenil on days 1 and 11 and of unlabeled compound on
days 2-10, in an 11-day daily dosing experiment.  No major differences
in metabolic patterns between sexes were observed.

Dichlobenil is metabolized via hydroxylation at the 3 or 4 position of
the phenyl group followed by sulfation or glucuronidation; or via
displacement of a chlorine atom followed by glutathione conjugation.
Glutathione conjugation appears to be saturable during repeated dosing.
The soil metabolite 2,6-dichlorobenzamide (BAM) was not identified as a
metabolite in the rat.

Radioactive residue levels were assayed in the liver, kidney, whole
blood, and plasma.  High residues were detected in the liver.  In a
time-course study of residue levels in various tissues from rats
receiving 2.5 mg/kg, the highest levels were found in the liver, kidney,
and some samples of kidney fat.  The highest radioactive levels were
found during 1-3 hours post dosing.  Thereafter, residue levels
decreased.  Recovery (96%) seven days after a single i.v. dose indicates
low residence time in tissues; slightly longer residence time following
oral exposure is suggested by 84-86% recovery 7 days after a single oral
dose.  No major sex-related differences were noted in tissue
distribution.

No metabolism or absorption studies are available for dichlobenil via
the dermal or inhalation routes.  The Agency is currently reviewing
metabolism studies for BAM.

3.3		FQPA Considerations

3.3.1	 	Adequacy of the Toxicity Data Base

The toxicology database used to assess pre- and/or post-natal exposure
to dichlobenil is adequate.  However, the toxicology database used to
assess pre- and/or post-natal exposure to the soil metabolite, BAM, is
incomplete.  Data from a 2-week oral toxicity study has been requested
to evaluate potential neurotoxic effects of BAM in mice.  The following
acceptable studies are available:

Dichlobenil

One developmental toxicity study in rats

One developmental toxicity study in rabbits

One two-generation reproduction study in rats

2,6-Dichlorobenzamide (BAM)

One developmental toxicity study in rabbits

One three-generation reproduction study in rats

3.3.2		Evidence of Neurotoxicity (Dichlobenil and BAM)

Olfactory toxicity was observed following dermal, inhalation, and
intraperitoneal (i.p.)

exposures to dichlobenil in five toxicity studies that were either
published in the open

literature (one dermal, two i.p. studies) or submitted to the Agency
(two inhalation

studies).  In each study, degeneration of the olfactory epithelium was
observed.  Since the

olfactory epithelium is composed of olfactory sensory neurons, damage to
the olfactory

epithelium is considered a neurotoxic effect.

BAM is considered neurotoxic.  Toxicity to the olfactory sensory neurons
was observed following single i.p. exposures of mice to BAM (Brittebo et
al. 1991).  In the 90-day oral toxicity study in rats, reduced muscle
tone was observed; however, the toxicological significance of this
finding is unclear, given the lack of reproducibility of the effect in
other studies, the age of the study itself (1967), and the fact that the
purity of the compound was not reported in the study.  Lethargy and
ataxia were observed in mice tested orally in a dose-range finding study
for the in vivo erythrocyte micronucleus assay.  The effects were
resolved after 24 hours.  In addition, in a two-week dietary study
recently submitted and not fully reviewed by the Agency (MRID 46892401),
clinical signs of toxicity (slightly decreased muscle tone, slight loss
of pinnae reflexes) were observed in mice at 2500 ppm (approximately
equal to 375 mg/kg/day).  Therefore, HED is requesting Guideline acute
and subchronic neurotoxicity screening batteries (OPPTS 870.6200) with
BAM.

<IP_ADDRESS>		Developmental Toxicity Studies (Dichlobenil)

Rat

In an Acceptable/Non-guideline, prenatal developmental toxicity study
(MRID 00147437), dichlobenil technical (purity not reported; batch#
FUN82B07A/FUX003000) was administered by gavage in 1% gum tragacanth to
25 pregnant Wistar Cpb:WU rats/sex/dose from gestation day (GD) 6-15
inclusive at daily dose levels of 0, 20, 60, or 180 mg/kg/day.  No
treatment-related mortality or clinical signs of toxicity were observed
in pregnant does in the study.

A 29% (P<0.01) and 36% (P<0.01) decrease in mean body weight gain was
observed during the dosing period in does treated at 60 and 180
mg/kg/day, resp.  This effect was accompanied by a 15% (P<0.01) and 21%
(P<0.01) decrease in food consumption at 60 and 180 mg/kg/day,
respectively, as well as a respective 19% (P<0.05) and 24% (P<0.01)
decrease in food efficiency.  During the post-dosing period (GD 16-21),
body weight gain, food consumption, and food efficiency values in mid-
and high-dose animals rebounded to levels that were similar to or
greater than those of controls.  The maternal LOAEL is 60 mg/kg bw/day,
based on decreased body weight gain, food consumption, and food
efficiency during dosing.  The maternal NOAEL is 20 mg/kg bw/day.

No treatment-related changes were observed in cesarean section
parameters (death, altered growth) for either embryos or fetuses.  It is
unclear from the study report whether statistical analysis was performed
for litter incidences of external, skeletal, or visceral observations.
With regard to external anomalies, a shallow dose-dependent increase in
the incidence of small subcutaneous hemorrhage or petechia was observed
(0/23, 1/22, 2/22, and 3/21 litters at 0, 20, 60, and 180 mg/kg/day);
however, the increase in the number of fetuses affected (0-3) was only
slightly increased across dose and not statistically significant.
Historical control incidences for this specific observation were not
reported.  However, the percentage of litters affected at all doses was
within the historical control range (0-20%) of litter incidences of
externally visible alterations.

An increased litter (13.6-14.3%) and fetal (3.1-3.5%) incidence of
unilateral supernumerary rib (14th) was observed at ≥ 60 mg/kg/day.
The fetal incidences were not statistically significantly different from
concurrent controls.  The litter incidence (19%) of bilateral
supernumerary rib (14th) was also increased at 180 mg/kg/day, as was the
fetal incidence (4.7%; P<0.05).  However, both the litter and fetal
incidences of supernumerary (14th) rib were below the historical control
incidences (32.26% and 10.86%, resp.).  An increase (P<0.01) in the
“degree” of absence of ossification of the sternebrae (expressed as
transformed ossification values per litter) was also observed at 180
mg/kg/day (7.03 vs. 0.59 in controls).  The increase was outside the
historical control range (0-0.31).  However, given that the concurrent
control value (0.59) was above the upper limit of the historical control
range and dose-response was lacking in the effect, the calculated value
is not considered toxicologically significant.

With respect to visceral anomalies, a very slight increase in the
malformations, unilateral microphthalmia and intestinal alteration of
the situs viscerum (combined with focal fibrosis of the peritoneum and
mesentery) was observed at the high dose in one animal in 1/21 litters
only.  The malformation, soft consistency of the lens/unilateral folded
retina, was observed in a different animal in 1/21 litters only.  The
incidence of each effect was above that of the historical controls
(1/2691 fetuses; 1/401 litters); however, fetal incidences were not
statistically significant and a dose-response was lacking at the doses
tested.  The developmental LOAEL was not identified.  The developmental
NOAEL is 180 mg/kg bw/day.

Rabbit

In an Acceptable/Non-guideline, prenatal developmental toxicity study
(MRID 41257302), dichlobenil technical (98.5% a.i.; lot#s 3 and 6;
batch# FUX010000) was administered by gavage in 1% gum tragacanth to 18
pregnant New Zealand white rabbits/sex/dose from gestation day (GD) 7-19
inclusive at daily dose levels of 0, 15, 45, or 135 mg/kg/day.  No
treatment-related mortality, clinical signs of toxicity (including
abortions), or gross pathology were observed in the study.

A decrease (129%; P<0.05) in body weight gain was observed during the
dosing period only (GD 7-19) in does treated at 135 mg/kg/day.  This
effect was accompanied by a 30% (P<0.01) decrease in food consumption at
the high dose during the dosing period only.  Body weight gain and food
consumption in high-dose animals rebounded during the post-dosing period
(GD 19-29).  The maternal LOAEL is 135 mg/kg bw/day, based on decreased
body weight gain and food consumption during dosing.  The maternal NOAEL
is 45 mg/kg bw/day.

Increases in total resorptions/dam (1.3) and post-implantation loss
(17.9%) were observed at 135 mg/kg/day.  Although the effects were not
dose-dependent, the incidences were outside the historical control range
and considered treatment-related.  Although generally occurring at very
low incidences (1-3 fetuses), several external, visceral, and skeletal
defects anomalies were reported at 135 mg/kg/day. These effects were not
observed in either concurrent or historical controls or were observed at
incidences outside historical control ranges and were therefore
considered toxicologically significant.  External anomalies included
bilateral open eye (3/115 fetuses; 3/14 litters), cleft palate, and
adactyly.  High-dose visceral anomalies included abnormal cystic
gallbladder and distended ureter with bilateral severe hydronephrosis.
Skeletal defects at 135 mg/kg/day were composed of malformed and
malpositioned right scapula, right radius absent with malpositioned ulna
and humerus, fused cervical vertebral arches, asymmetrically ossified
and fused cervical vertebra centra, abnormally shaped cranium with
enlarged and misshapen fontanelle, enlarged fontanelle (19/115 fetuses;
13/14 litters), misshapen frontals (2/115 fetuses; 2/14 litters), skull
and frontals foreshortened and nasal malpositioned, and major fusion of
sternebrae (3/115 fetuses; 3/14 litters).

The developmental LOAEL is 135 mg/kg bw/day, based on increased number
of total

resorptions/dam and post-implantation loss; and increased incidences of
external (cleft

palate, adactyly, bilateral open eye), visceral (abnormal cystic
gallbladder, distended

ureter with bilateral severe hydronephrosis), and skeletal (malformed
and malpositioned

right scapula, right radius absent with malpositioned ulna and humerus,
fused cervical

vertebral arches, asymmetrically ossified and fused cervical vertebra
centra, abnormally

shaped cranium with enlarged and misshapen fontanelle, enlarged
fontanelle, misshapen

frontals, skull and frontals foreshortened and nasal malpositioned, and
major fusion of

sternebrae) anomalies.  The developmental NOAEL is 45 mg/kg bw/day.

<IP_ADDRESS>		Reproductive Toxicity Study (Dichlobenil)

In an Acceptable/Non-guideline, two-generation reproduction study (MRIDs
41257303 and 42239101), dichlobenil technical (99.4% a.i.; lot#s 4 and
5; batch# F6N87EO8A/FUX011000) was administered in the diet to
Crl:CD(SD)BR rats (30/sex/dose in the P generation; 25/sex/dose in the
F1 generation) at daily dose levels of 0, 60, 350, or 2000 ppm
(equivalent to 0, 3, 17.5, or 100 mg/kg/day) for 2 consecutive
generations.  One (of 30) high-dose P males was found dead during week
14 of the study.  The cause of death was liver necrosis and hemorrhage
(MRID 42239101).  One (of 25) F1 high-dose males was sacrificed in
extremis during week 12 of the study due after an accidental injury to
the snout.  Both deaths were considered incidental to treatment.  There
were no treatment-related clinical signs of toxicity in the study.

During the 10-week premating period for P animals, mean cumulative body
weight gains were decreased by 25-26% (P<0.05) at 2000 ppm in both males
and females.  Similarly, mean overall body weight gains for F1 males
were decreased by 25% during the 10-week premating period and by 18% for
F1 females at 2000 ppm.  During gestation, mean body weight gains were
decreased by 13-14% in both P and F1 females at 2000 ppm.  Decrements in
body weight gains were not observed in adult females of either
generation during lactation.  Mean food consumption at 2000 ppm was
decreased by 11-33% (P<0.001) in P males and by 17-28% (P<0.001) in P
females during premating.  In F1 males, mean food consumption during
premating was decreased by 16-21% (P<0.001) and by 16-20% (P<0.001) in
F1 females at 2000 ppm.  Mean food consumption for P and F1 females
during gestation and lactation was not reported.

No treatment-related effects were observed on fertility index, fecundity
index, gestation index, or mean gestation length in either P or F1
females.  The mean number of implantations/dam was unreported for P
females and decreased at 2000 ppm in F1 females (12.3 vs. 14.6 in
controls).  The parental systemic LOAEL is 2000 ppm (100 mg/kg bw/day),
based on decreased body weight gains during premating (males and
females) and gestation (females) in both generations, decreased food
consumption during premating in both generations (males and females),
and decreased number of implantations/dam in F1 females.  The parental
systemic NOAEL is 350 ppm (17.5 mg/kg bw/day).  The reproductive LOAEL
is 2000 ppm (100 mg/kg bw/day), based on decreased number of
implantations/dam in F1 females.  The reproductive NOAEL is 350 ppm
(17.5 mg/kg bw/day).

 dam at 2000 ppm.  At ≥ 350 ppm, the mean pup body weight of F1
offspring was decreased by 16-23% (P<0.05) from postnatal day (PND) 4
(precull)-21.  The effect was dose-dependent.  In F2 offspring, mean pup
body weight was also dose-dependently decreased by 19-22% (P<0.05) from
PND 14-21.  An increased incidence of pelvic cavitation of the kidney at
2000 ppm (3% vs. 0%) was observed during necropsy in weanling F2
offspring; however, the incidence was similar to the sporadic incidence
observed in P and F1 animals and was not considered toxicologically
significant.  The offspring LOAEL is 350 ppm (17.5 mg/kg bw/day), based
on decreased body weight during weaning in both generations.  The
offspring NOAEL is 60 ppm (3 mg/kg bw/day).

<IP_ADDRESS>		Developmental Toxicity Study (BAM)

Rabbit

In an Acceptable/Non-guideline, prenatal developmental toxicity study
(MRID 43003601), 2,6-dichlorobenzamide (99.4% a.i.; batch# FUX001000)
was administered by gavage in 1% gum tragacanth to 16 pregnant New
Zealand white rabbits/sex/dose from gestation day (GD) 7-19 inclusive at
daily dose levels of 0, 10, 30, or 90 mg/kg/day.  Five (of 16) females
treated at 90 mg/kg/day were sacrificed in extremis.  Three of the 5
sacrificed high-dose dams had late abortions (GD 19, 21, and 22, resp.).
The incidence of abortion followed by sacrifice at 0, 10, and 30
mg/kg/day was 1/16, 1/16, and 0/16, resp.  The other 2/5 high-dose
animals were sacrificed moribund.  Moribund condition followed by
sacrifice was observed in 1/16, 0/16, and 2/16 animals at 0, 10, and 30
mg/kg/day, resp.  The incidence of thin appearance was increased at 90
mg/kg/day (10/16), whereas the incidences at 0, 10, and 30 mg/kg/day
were 1/16, 0/16, and 2/16, resp.

A decrease (129%) in mean body weight gain, relative to controls, was
observed during the dosing period (GD 7-19) in does treated at 90
mg/kg/day.  Similarly, food consumption at 90 mg/kg/day was decreased
during the dosing period by 49%, relative to controls.  Body weight gain
and food consumption in high-dose animals rebounded above control levels
during the post-dosing period (GD 20-28).  No treatment-related gross
pathology was observed.  The maternal LOAEL is 90 mg/kg bw/day, based on
increased incidences of clinical signs (late abortion, thin appearance)
and decreased (severe) body weight gain and food consumption during
dosing.  The maternal NOAEL is 30 mg/kg bw/day.

No treatment-related effects were observed on several developmental
endpoints, including the number of resorptions, post-implantation loss,
litter size, and sex ratio.  Mean fetal body weight at 90 mg/kg bw/day
(33.9 g) was decreased by 6%, relative to controls; however, the change
was not statistically significant and the mean value fell within the
historical control range (27.7 g-39.4 g).  No treatment-related changes
were observed on the incidences of external defects.

An increase in the incidence of bipartite interparietal bone was
observed at 90 mg/kg bw/day.  Litter incidences were 1/14, 1/15, 2/14,
and 3/11 litters at 0, 10, 30, and 90 mg/kg/day.  Bipartite
interparietal bone is considered a malformation in rats (Solecki et al.
2001).  Historical control data were not provided for the litter
incidences of bipartite interparietal bone, and fetal incidences only
were reported for the current study.  However, the fetal incidences were
not statistically significant different from concurrent controls, and
the concurrent control fetal incidence (0.8%) exceeded that of the
historical controls (0.3%).  An increase in the incidence of postcaval
lung lobe agenesis was also observed at 90 mg/kg bw/day.  Litter
incidences were 0/14, 0/15, 1/14, and 3/11 at 0, 10, 30, and 90
mg/kg/day.  The fetal incidence of postcaval lung lobe agenesis at 90
mg/kg bw/day (3.2%) exceeded that of the historical controls (1.2%),
whereas that at 30 mg/kg bw/day (0.9%) did not.  The developmental LOAEL
is 90 mg/kg bw/day, based on increased incidences of late abortion and
skeletal (bipartite interparietal bone) and visceral (postcaval lung
lobe agenesis) anomalies.  The developmental NOAEL is 30 mg/kg bw/day.

<IP_ADDRESS>		Reproductive Toxicity Study (BAM)

In an Acceptable/Non-guideline, 3-generation reproduction study (MRID
42940204), 2,6-dichlorobenzamide (99.5% a.i.; batch # 195) was
administered in the diet to Long-Evans rats (10 males/dose and 20
females/dose in the P, F1, and F2 generations) at daily dose levels of
0, 60, 100, or 180 ppm (equivalent to 0, 4.5, 7.5, or 13.5 mg/kg/day)
for 3 consecutive generations.  Two litters were produced in each
generation.  The number of pups per litter was counted on postnatal days
(PNDs) 1, 5, and 21 (also weighed).  Litters were culled to ten animals
each on PND 5.  P, F1, and F2 generation parental animals were weighed
and examined for gross pathology on the day of termination
(unspecified).  Organ weights were measured, and histopathology was
performed on select F3b weanlings only.

No treatment-related mortality was observed in the P, F1b, or F2b
parental generations.  A 6% (P<0.05) decrease in mean parental terminal
body weight was observed at 180 ppm in the F2b generation; however, the
decrease was not biologically significant and not observed in P or F1b
parental animals.  No treatment-related gross pathology was observed in
P, F1b, or F2b parental animals.  Fertility and gestation indices were
similar across treatment groups in P, F1, and F2 generation dams.  The
parental systemic LOAEL was not observed.  The parental systemic NOAEL
is 180 ppm (13.5 mg/kg bw/day).  The reproductive LOAEL was not
observed.  The reproductive NOAEL is 180 ppm (13.5 mg/kg bw/day).

No treatment-related differences were observed in the mean number of
pups per litter on PNDs 1, 5 (pre-cull), or 21 in the F1, F2 or F3
generations.  Viability and lactation indices were similar across the
treatment groups in F1, F2, and F3 generation pups.  Mean survival from
birth to PND 5 (viability index) was slightly reduced (86.2%, P<0.01;
vs. 95.7% in controls) at 180 ppm in the F3b generation; however this
decrease was not observed in any other generation.  In addition, mean
survival from birth to weaning was similar across dose for each of the
three generations of offspring.  Hyperexcitability was observed in pups
(number not reported) from four litters in the F1b generation only.

 ≥100 ppm in females was observed in this same generation. Changes in
F3b generation weanling mean organ weights were not considered
toxicologically significant, however, due to a lack of histopathological
correlates in the liver and kidney.  The offspring LOAEL was not
observed.  The offspring NOAEL is 180 ppm (13.5 mg/kg bw/day).

3.3.5		Additional Information from Literature Sources

Dichlobenil and its soil metabolite, BAM, have both been shown to be
olfactory toxicants

in adult animals following intraperitoneal (i.p.) exposure (Brandt et
al. 1990; Brittebo et

al. 1991; Eriksson and Brittebo 1995).  Dichlobenil alone also causes
olfactory toxicity in

neonatal animals following subcutaneous (s.c.) exposure (Eriksson and
Brittebo 1995).

Olfactory toxicity has also been demonstrated after dermal exposure of
dichlobenil

(Deamer at al. 1994) to adult animals.

Experimental evidence suggests that dichlobenil and BAM are activated to
the ultimate

olfactory toxicant (currently unknown) by cytochrome P (CYP) 450 enzymes
located in

Bowman’s glands of the nasal mucosa (Brandt et al. 1990; Brittebo
1997).  It is suggested

that damage to the olfactory epithelium is a secondary effect of damage
to the Bowman’s

glands (primary lesion), which are located in the lamina propria of the
olfactory mucosa

(Brandt et al. 1990; Brittebo et al. 1991).  Since CYP 450s are abundant
in both the

olfactory epithelium and Bowman’s glands, both areas may be sites of
bioactivation of

dichlobenil and BAM (Harkema et al. 2006).  Further, it has been
hypothesized that

damage to the olfactory epithelium, as well as the liver, may be
mediated by

hydroxylated metabolites of dichlobenil or BAM, the metabolites of which
have been

shown in vitro to be uncouplers of oxidative phosphorylation in rat
liver mitochondria

(Brittebo et al. 1991).

3.3.6	 	Pre-and/or Postnatal Toxicity (Dichlobenil and BAM)

Determination of Susceptibility

Dichlobenil

There was no evidence of increased prenatal susceptibility in the
developmental toxicity

studies in rats or rabbits.  In the rat developmental toxicity study, no
developmental

effects were observed at the highest dose tested; maternal toxicity was
observed at

the mid dose.  In the rabbit developmental toxicity study, an increase
in total

resorptions/dam, post-implantation loss, as well as external, visceral,
and skeletal

anomalies were observed at the high dose.  However, maternal toxicity
(decreased body

weight gain and food consumption) was also observed at the high dose.

Evidence of increased pre-/post-natal susceptibility was observed in
the two-generation

reproduction study in rats.  In this study, toxicologically significant
decreases in body

weight gain (premating and gestation) and food consumption (premating)
were observed

at the high dose in both parental and F1 generation adults.  However,
decreased body

weight was observed during weaning  in both F1 (16-23%) and F2 (19-22%)
generation

pups at the next lower (mid) dose.

Overall, HED concluded that there is evidence of increased
susceptibility to offspring

following pre-/post-natal exposure to rats in the two-generation
reproduction study in

rats.

BAM

There was no evidence of increased prenatal susceptibility in the
developmental toxicity

study in the rabbit or in the three-generation reproduction study in the
rat.  In the rabbit

developmental toxicity study, an increase in the incidences of late
abortion, as well as

visceral and skeletal anomalies were observed at the high dose.
However, severe

maternal toxicity [decreased body weight gain (>15%) and food
consumption (49%) and

late abortion] was observed at the same dose.  In the rat
three-generation reproduction

study, no adverse effects were observed up to the highest dose tested in
either generation.

Degree of Concern Analysis

Dichlobenil

HED considers the concern for increased susceptibility to offspring
following pre-/post-

natal exposure to dichlobenil to be low.  The Agency proposes to
regulate potential

incidental oral exposure by using the NOAEL from the two-generation
reproduction

study in rats.  HED is confident in this NOAEL, which is six times lower
than the dose

(LOAEL) at which decreased pup body weight was observed in the
two-generation

reproduction study in rats.

BAM

Since there is no evidence of increased pre-/post-natal susceptibility
in the developmental

toxicity study in the rabbit or in the three-generation reproduction
study in the rat, there is

no concern.

Recommendation for a Developmental Neurotoxicity Study (Dichlobenil

                and BAM)

Abnormal offspring behavior, CNS malformations or neuropathology in
offspring, effects

on offspring brain weights, and effects on offspring sexual maturation
were not observed

in any study for dichlobenil..  However, neuropathology (olfactory
sensory neuron

toxicity) was observed in both adult and neonatal animals following i.p.
and s.c.

exposure, respectively, to dichlobenil (Eriksson and Brittebo 1995).
Toxicity to olfactory

sensory neurons was also observed in adult animals following a single
i.p. dose of BAM

(Brittebo et al. 1991).

Clinical signs of neurotoxicity were observed in three studies for BAM.
In the subchronic oral toxicity study in the rat, decreased skeletal
muscle tone was observed with increasing severity at the mid-high and
high doses.  However, the toxicological significance of this finding is
unclear, given the lack of reproducibility of the effect in other
studies, the age of the study itself (1967), and the fact that the
purity of the compound was not reported in the study.

Lethargy and ataxia were observed after a single dose in mice in an oral
dose-range finding study for the in vivo erythrocyte micronucleus assay
for BAM.  The effects were transient (resolved within 24 hours).  In
addition, in a two-week dietary study recently submitted and not fully
reviewed by the Agency (MRID 46892401), clinical signs of toxicity
(slightly decreased muscle tone, slight loss of pinnae reflexes) were
observed in mice at 2500 ppm (approximately equal to 375 mg/kg/day).
Until acute and subchronic neurotoxicity batteries are received and
evaluated by the Agency, their absence is considered a data gap.  A
developmental neurotoxicity study is pending, based on receipt and
review of the requested acute and subchronic neurotoxicity screening
batteries.

FQPA Safety Factor (SF) for Infants and Children (Dichlobenil and

                BAM)

Dichlobenil

Data from the published literature (Eriksson and Brittebo 1995) indicate
that

olfactory toxicity following s.c. (neonates) or i.p. (adults) exposure
is similar in both

subpopulations of mice.  However, a comparative assessment of the tissue
dose of

dichlobenil following s.c. or i.p. administration cannot be made based
on the existing

data.  Therefore, the risk assessment team recommends that the 10X FQPA
SF, in the

form of a UFDB be retained until the potential of dichlobenil to induce
olfactory toxicity

in neonates relative to adults via the oral route is assessed.

BAM

The risk assessment team recommends that the 10X FQPA SF, in the form of
two UFDBs,

be retained for most exposure scenarios.  The first UFDB of 3X
corresponds to the lack of

data assessing the potential of dichlobenil (parent) to induce olfactory
toxicity in neonates

relative to adults via the oral route is assessed.  HED believes that a
value of 3X (rather

than 10X) for the first UFDB is warranted based on the observation that
approximately 3-

fold higher doses of BAM are needed to induce levels of olfactory
toxicity that are

similar to those caused by dichlobenil, following a single i.p.
injection of either

compound to adult mice (Brandt et al. 1990; Brittebo et al. 1991).  The
second UFDB of

3X corresponds to the incompleteness of the database with regard to the
systemic

neurotoxic potential of BAM.

The risk assessment team also recommends that the FQPA SF be retained,
but reduced to

3X for the acute dietary exposure scenario (general population) only,
since a LOAEL

based on clinical signs of neurotoxicity was utilized to extrapolate a
NOAEL for this

scenario.  HED believes this reduction is warranted based on the
decrease in severity of

effects that was observed with decreasing dose in the pilot study for
the in vivo mouse

micronucleus assay.

Hazard Identification and Toxicity Endpoint Selection

Dichlobenil

A summary of the toxicological endpoints and doses chosen for the
relevant exposure scenarios for human risk assessment is found in Table
3.2.

Table 3.2.  Summary of Toxicological Doses and Endpoints for Dichlobenil
for Use in Dietary and Non-Occupational Human Health Risk Assessments

Exposure Scenario	Point of Departure	Uncertainty/FQPA Safety Factors
RfD, PAD, Level of Concern for Risk Assessment	Study and Toxicological
Effects

Acute Dietary (General population, including infants and children)	N/A
N/A	N/A	An endpoint of concern (effect) attributable to a single dose
was not identified in the database. Quantification of acute risk to
general population, including infants and children, is not required.

Acute Dietary (Females 13-49 years of age)	NOAEL = 45

mg/kg/day	UFA = 10X

UFH = 10X

FQPA SF4 = 10X

(includes UFDB = 10X)	aRfD = 0.45 mg/kg/day

aPAD = 0.045 mg/kg/day	Developmental toxicity (rabbit) Offspring LOAEL =
135 mg/kg/day based on increased incidences of total resorptions/dam,
post-implantation loss, and fetal external, visceral, and skeletal
anomalies (see tox table)

Chronic Dietary (All populations)	NOAEL = 1

mg/kg/day	UFA = 10X

UFH = 10X

FQPA SF4 = 10X

(includes UFDB = 10X)	cRfD = 0.01 mg/kg/day

-GT and periportal hypertrophy of hepatocytes (M); olfactory toxicity
was assayed and not observed in this study

Incidental Oral

Short- and Intermediate-Term (1-30 days and 1-6 months)	NOAEL = 3

mg/kg/day	UFA = 10X

UFH = 10X

FQPA SF4 = 10X

(includes UFDB = 10X)	Residential LOC for MOE = 1000	2-generation
reproduction (rat) Offspring LOAEL = 17.5 mg/kg/day based on decreased
body weight during weaning in both generations

Dermal

Short-, Intermediate-, and Long-Term (1-30 days, 1-6 months, and > 6
months)	NOAEL = 25

mg/kg/day	UFA = 10X

UFH = 10X

FQPA SF4 = 10X

(includes UFDB = 10X)	Residential LOC for MOE = 1000

OccupationalLOC for MOE = 100	5-day dermal (mouse; literature study 1)
LOAEL = 50 mg/kg/day based on olfactory epithelial damage

Inhalation

Short-, Intermediate-, and Long-Term (1-30 days, 1-6 months, and >6
months)	NOAEL = 0.17

mg/kg/day 2	UFA = 10X

UFH = 10X

FQPA SF4 = 10X

(includes UFDB = 10X)	Residential LOC for MOE = 1000

OccupationalLOC for MOE = 100	7-day inhalation (rat; dose-range finding)
LOAEL = 0.30 mg/kg/day 3 based on nasal degeneration

Cancer	Classification: Group C, possible human carcinogen; RfD approach
should be used for quantification of human risk (2nd Carcinogenicity
Peer Review, 1995)

Abbreviations: UF = uncertainty factor, UFA = extrapolation from animal
to human (interspecies), UFH = potential variation in sensitivity among
members of the human population (intraspecies), FQPA SF = FQPA Safety
Factor, UFDB = to account for the absence of key data, NOAEL = no
observed adverse effect level, LOAEL = lowest observed adverse effect
level, RfD = reference dose (a = acute, c = chronic), PAD = population
adjusted dose, MOE = margin of exposure, LOC = level of concern, N/A =
Not Applicable

1   HYPERLINK
"http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Search&itoo
l=pubmed_Abstract&term=%22Deamer+NJ%22%5BAuthor%5D"  Deamer NJ ,
HYPERLINK
"http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Search&itoo
l=pubmed_Abstract&term=%22O%27Callaghan+JP%22%5BAuthor%5D"  O'Callaghan
JP ,   HYPERLINK
"http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Search&itoo
l=pubmed_Abstract&term=%22Genter+MB%22%5BAuthor%5D"  Genter MB . (1994).
Olfactory toxicity resulting from dermal application of
2,6-dichlorobenzonitrile (dichlobenil) in the C57Bl mouse.
Neurotoxicology 15(2):287-93

2 Calculated as follows: [(NOAEL) x (m3 / 1000 L) x (24,550 / MW) x
(0.100 mg/kg/day / ppm for a young rat)], where NOAEL= 12 mg/m3 from
28-day inhalation toxicity study (rat) and MW=172

3 Calculated as follows: [(LOAEL) x (m3 / 1000 L) x (24,550 / MW) x
(0.100 mg/kg/day / ppm for a young rat)], where LOAEL= 21 mg/m3 from
7-day inhalation range finding study (rat) and MW=172

4 The 10X FQPA SF has been retained in the form of a UFDB for the lack
of olfactory toxicity data in neonates and/or adults following oral
exposure to dichlobenil

3.5.1 		aRfD - Females age 13-49

The aRfD for females 13-49 years of age was established based on the
NOAEL (100 mg/kg/day) from the developmental toxicity study in rabbits.
The LOAEL of 135 mg/kg/day is based on increased incidences of total
resorptions/dam, post-implantation loss, and fetal external, visceral,
and skeletal anomalies.  This study and endpoint are the most
appropriate for the population of concern, namely, women of childbearing
age.  The FQPA SF has been retained in the form of a UFDB for this
exposure scenario to account for the lack of olfactory toxicity data in
adults and neonates following oral exposure to dichlobenil.

3.5.2	 	aRfD - General Population

An acute dietary endpoint for all populations, including infants and
children, was not established since an endpoint of concern attributable
to a single dose was not identified in the database.

3.5.3	 	cRfD

The cRfD was established based on the NOAEL (1 mg/kg/day) from the
chronic toxicity

study in the dog.  The LOAEL of 6 mg/kg/day is based on increased liver
weights and

increased serum cholesterol, triglyceride, phospholipid, and alkaline
phosphatase levels

-glutamyl transferase levels and periportal hypertrophy of
hepatocytes in males.  The NOAEL of 1 mg/kg is the lowest in the
database.  In addition, the study duration is appropriate for the
duration of exposure.  Although olfactory toxicity was assayed and not
observed in adult dogs in this study, the 10X FQPA SF has been retained
in the form of a UFDB for this exposure scenario to account for the lack
of olfactory toxicity data in neonates following oral exposure to
dichlobenil.

3.5.4	 	Incidental Oral Exposure (Short- and Intermediate-Term)

The effects of concern that are relevant to the selection of the short-
and

intermediate-term incidental oral doses are decreased body weight
observed during

weaning in both generations at 17.5 mg/kg/day in the two-generation
reproduction study

in rats.  The study length is appropriate for the durations of exposure,
namely, 1-30 days

(short-term) and 1-6 months (intermediate-term); and the NOAEL of 3
mg/kg/day is

protective of the population of concern, namely, infants and children.
However, the 10X FQPA SF has been retained in the form of a UFDB for
this exposure scenario to account for the lack of olfactory toxicity
data in neonates following oral exposure to dichlobenil.

3.5.5	 	Dermal Absorption

No dermal absorption study is available in the database.  Since a
route-specific toxicity study (5-day dermal in mouse) is being used for
dermal risk assessment, estimation of dermal absorption is not
necessary.

3.5.6 		Dermal Exposure (Short-, Intermediate-, and Long-Term)

The effects of concern that are relevant to the selection of the short-,
intermediate-, and

long-term dermal doses are olfactory epithelial damage observed in a
published 5-day

dermal toxicity study in rats (Deamer et al. 1994).  The route of
exposure of this study is

ideal for these dermal exposure scenarios.  However, the 10X FQPA SF has
been retained

in the form of a UFDB for this exposure scenario to account for the lack
of olfactory toxicity data in neonates following exposure to
dichlobenil.

3.5.7 		Inhalation Exposure (Short-, Intermediate-, and Long-Term)

The 7-day dose-range finding inhalation toxicity study in the rat was
chosen for the

short-, intermediate-, and long-term inhalation exposure scenarios.  The
effect of concern

that is relevant to the selection of  short-, intermediate, and
long-term inhalation

endpoints is nasal degeneration observed at 0.3 mg/kg/day (NOAEL = 0.17
mg/kg/day)

in this study.  Although the route of exposure of this study is ideal
for these exposure

scenarios, the 10X FQPA SF has been retained in the form of a UFDB to
account for the

lack of olfactory toxicity data in neonates following exposure to
dichlobenil.

BAM

A summary of the toxicological endpoints and doses chosen for the
relevant exposure scenarios for human risk assessment is found in Table
3.3.

Table 3.3.  Summary of Toxicological Doses and Endpoints for
2,6-Dichlorobenzamide (BAM) for Use in Dietary and Non-Occupational
Human Health Risk Assessments

Exposure Scenario	Point of Departure	Uncertainty/FQPA Safety Factors
RfD, PAD, Level of Concern for Risk Assessment	Study and Toxicological
Effects

Acute Dietary (General population, including infants and children)	LOAEL
= 100 mg/kg/day

	UFA = 10X

UFH = 10X

FQPA SF4,5 = 10X (includes UFL = 3X and UFDB = 3X)

	aRfD = 1 mg/kg/day

aPAD = 0.1 mg/kg/day	Dose-range finding assay for in vivo mouse
erythrocyte micronucleus assay LOAEL = 100 mg/kg/day based on lethargy
after a single oral dose

Acute Dietary (Females 13-49 years of age)	NOAEL = 30 mg/kg/day	UFA =
10X

UFH = 10X

FQPA SF5,6 = 10X

(includes UFDB = 10X)	aRfD = 0.30 mg/kg/day

aPAD = 0.03 mg/kg/day	Developmental toxicity (rabbit) Offspring LOAEL =
90 mg/kg/day based on increased incidences of  late abortion and
skeletal (bipartite interparietal bone) and visceral (postcaval lung
lobe agenesis) anomalies

Chronic Dietary (All populations)	NOAEL = 4.5

mg/kg/day	UFA = 10X

UFH = 10X

FQPA SF5,6 = 10X

(includes UFDB = 10X)	cRfD = 0.045 mg/kg/day

cPAD = 0.0045 mg/kg/day	Chronic toxicity (dog) LOAEL = 12.5 mg/kg/day
based on decreased body weight and body weight gain

Incidental Oral

Short- and Intermediate-Term (1-30 days and 1-6 months)	NOAEL = 14

mg/kg/day	UFA = 10X

UFH = 10X

FQPA SF5,6 = 10X

(includes UFDB = 10X)	Residential and Occupational LOC for MOE = 1000
90-day oral (rat) LOAEL = 49 mg/kg/day based on decreased body weight
gain (M) and reduced skeletal muscle tone (day 4 only in males; days 91
and 92 only in females)

Dermal

Short-, Intermediate-, and Long-Term (1-30 days, 1-6 months, and >6
months) 7	NOAEL = 25

mg/kg/day	UFA = 10X

UFH = 10X

FQPA SF5,6 = 10X

(includes UFDB = 10X)	Residential and Occupational LOC for MOE = 1000
5-day dermal using dichlobenil (mouse; literature study 1) LOAEL = 50
mg/kg/day based on olfactory epithelial damage

Inhalation

Short-, Intermediate-, and Long-Term (1-30 days, 1-6 months, and >6
months) 7	NOAEL = 0.17

mg/kg/day 2	UFA = 10X

UFH = 10X

FQPA SF5,6 = 10X

(includes UFDB = 10X)	Residential and Occupational LOC for MOE = 1000
7-day inhalation using dichlobenil (rat; dose-range finding) LOAEL =
0.30 mg/kg/day 3 based on nasal degeneration

Cancer	Classification: Formally unclassified; however, NOAEL in
carcinogenicity study similar to that for parent (dichlobenil);
therefore “Group C, possible human carcinogen” (former system); RfD
approach appropriate for quantification of human risk

Abbreviations: UF = uncertainty factor, UFA = extrapolation from animal
to human (interspecies), UFH = potential variation in sensitivity among
members of the human population (intraspecies), FQPA SF = FQPA Safety
Factor, UFL = use of a LOAEL to extrapolate a NOAEL, UFDB = to account
for the absence of key data, NOAEL = no observed adverse effect level,
LOAEL = lowest observed adverse effect level, RfD = reference dose (a =
acute, c = chronic), PAD = population adjusted dose, MOE = margin of
exposure, LOC = level of concern, N/A = Not Applicable

1   HYPERLINK
"http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Search&itoo
l=pubmed_Abstract&term=%22Deamer+NJ%22%5BAuthor%5D"  Deamer NJ ,
HYPERLINK
"http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Search&itoo
l=pubmed_Abstract&term=%22O%27Callaghan+JP%22%5BAuthor%5D"  O'Callaghan
JP ,   HYPERLINK
"http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Search&itoo
l=pubmed_Abstract&term=%22Genter+MB%22%5BAuthor%5D"  Genter MB . (1994).
Olfactory toxicity resulting from dermal application of
2,6-dichlorobenzonitrile (dichlobenil) in the C57Bl mouse.
Neurotoxicology 15(2):287-93

2 Calculated as follows: [(NOAEL) x (m3 / 1000 L) x (24,550 / MW) x
(0.100 mg/kg/day / ppm for a young rat)], where NOAEL= 12 mg/m3 from
28-day inhalation toxicity study (rat) and MW=172

3 Calculated as follows: [(LOAEL) x (m3 / 1000 L) x (24,550 / MW) x
(0.100 mg/kg/day / ppm for a young rat)], where LOAEL= 21 mg/m3 from
7-day inhalation range finding study (rat) and MW=172

4 The FQPA SF has been retained in the form of a UFL, because a LOAEL
was used to extrapolate a

NOAEL

5 The FQPA SF has been retained in the form of a UFDB for the lack of
acute and subchronic olfactory toxicity data in neonates following oral
exposure to dichlobenil

6 The FQPA SF has been retained in the form of a UFDB for the lack of
neurotoxicity data

7 In the absence of route-specific data, endpoints for all dermal and
inhalation exposure scenarios were identical to those for dichlobenil
(parent), since olfactory toxicity has been observed following i.p.
administration of BAM in mice [  HYPERLINK
"http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Search&itoo
l=pubmed_Abstract&term=%22Brittebo+EB%22%5BAuthor%5D"  Brittebo EB ,
HYPERLINK
"http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Search&itoo
l=pubmed_Abstract&term=%22Eriksson+C%22%5BAuthor%5D"  Eriksson C ,
HYPERLINK
"http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Search&itoo
l=pubmed_Abstract&term=%22Feil+V%22%5BAuthor%5D"  Feil V ,   HYPERLINK
"http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Search&itoo
l=pubmed_Abstract&term=%22Bakke+J%22%5BAuthor%5D"  Bakke J ,   HYPERLINK
"http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Search&itoo
l=pubmed_Abstract&term=%22Brandt+I%22%5BAuthor%5D"  Brandt I . (1991).
Toxicity of 2,6-dichlorothiobenzamide (chlorthiamid) and
2,6-dichlorobenzamide in the olfactory nasal mucosa of mice.   HYPERLINK
"javascript:AL_get(this,%20'jour',%20'Fundam%20Appl%20Toxicol.');"
Fundam Appl Toxicol  17(1):92-102].

3.5.8		aRfD - Females age 13-49

The aRfD for females 13-49 years of age was established based on the
LOAEL from the

developmental toxicity study in rabbits.  The LOAEL of 90 mg/kg/day is
based on

increased incidences of  late abortion and skeletal (bipartite
interparietal bone) and

visceral (postcaval lung lobe agenesis) anomalies.  This study and
endpoint are the most

appropriate for the population of concern, namely, women of childbearing
age.  The 10X

FQPA SF has been retained in the form of a UFDB for this exposure
scenario to account

for the lack of olfactory toxicity data in adults and neonates following
oral exposure to

dichlobenil or BAM, as well as for the lack of systemic neurotoxicity
data for BAM.  It is noted

that approximately 3-fold higher doses of BAM are needed to induce
levels of olfactory

toxicity that are similar to those caused by dichlobenil, following a
single i.p. injection of

either compound to adult mice (Brandt et al. 1990; Brittebo et al.
1991).

3.5.9	 	aRfD - General Population

The aRfD for the general population, including infants and children, was
established based on the LOAEL from the dose-range finding assay for the
in vivo mouse erythrocyte micronucleus assay.  The LOAEL of 100
mg/kg/day is based on lethargy following a single oral dose of BAM.  A
NOAEL was not identified in this study.  Since a LOAEL was used to
estimate a point of departure for this exposure scenario, the FQPA SF
has been retained in the form of a 3X UFL.  The 10X FQPA SF is also
composed of 3X UFDB to account for the lack of olfactory toxicity data
in adults and neonates following oral exposure to BAM or dichlobenil.

3.5.10	 	cRfD

The cRfD was established based on the NOAEL (4.5 mg/kg/day) from the
chronic

toxicity study in the dog.  The LOAEL of 12.5 mg/kg/day is based on
decreased body weight and body weight gain.  The NOAEL of 4.5 mg/kg is
the lowest in the BAM database.  In addition, the study duration is
appropriate for the duration of exposure.  The FQPA SF has been retained
in the form of a 10X UFDB for this exposure scenario to  account for the
lack of olfactory toxicity data in neonates following oral exposure to
BAM or dichlobenil, as well as the lack of systemic neurotoxicity data
for BAM.

3.5.11	 	Incidental Oral Exposure (Short- and Intermediate-Term)

The effects of concern that are relevant to the selection of the short-
and

intermediate-term incidental oral doses are decreased body weight gain
observed in males

and reduced skeletal muscle tone (observed on day 4 only in males and on
days 91 and 92

only in females) at  49 mg/kg/day in the 90-day oral toxicity study in
rats.  The study

length and effects are ideal for the durations of exposure, namely, 1-30
days (short-term)

and 1-6 months (intermediate-term).  The NOAEL of 14 mg/kg/day is
protective of the

population of concern, namely, infants and children.  The 10X FQPA SF
has been

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 in the form of a UFDB for this exposure scenario to account for the
lack of

olfactory toxicity data in adults and neonates following oral exposure
to dichlobenil or

BAM, as well as for the lack of systemic neurotoxicity data for BAM.  .

3.5.12	 	Dermal Absorption

No dermal absorption study is available in the database.  Since a
route-specific toxicity study (5-day dermal in mouse using dichlobenil)
is being used for dermal risk assessment, calculation of dermal
absorption is not necessary.

3.5.13		Dermal Exposure (Short-, Intermediate-, and Long-Term)

The effects of concern that are relevant to the selection of the short-,
intermediate-, and

long-term dermal doses are olfactory epithelial damage observed in a
published 5-day

dermal toxicity study in rats (Deamer et al. 1994) using dichlobenil.
The route of

exposure of this study is ideal for these dermal exposure scenarios.
However, the

FQPA SF has been retained in the form of a 10X UFDB for this exposure
scenario to

account for the lack of olfactory toxicity data in neonates following
oral exposure to

dichlobenil or BAM, as well as for the lack of systemic neurotoxicity
data for BAM.

Based on the results from two published literature studies of BAM via
the intraperitoneal

route, BAM is expected to cause olfactory toxicity at doses 3X higher
than dichlobenil.

3.5.14		Inhalation Exposure (Short-, Intermediate-, and Long-Term)

The 7-day dose-range finding inhalation toxicity study using dichlobenil
in the rat was

chosen for the short-, intermediate-, and long-term inhalation exposure
scenarios.  The

effect of concern that is relevant to the selection of  short-,
intermediate, and long-term

inhalation endpoints is nasal degeneration observed at 0.3 mg/kg/day
(NOAEL = 0.17

mg/kg/day) in this study.  Although the route of exposure of this study
is ideal for these

exposure scenarios, the FQPA SF has been retained in the form of a 10X
UFDB to account

for the lack of olfactory toxicity data in neonates following oral
exposure to dichlobenil

or BAM, as well as for the lack of systemic neurotoxicity data for BAM.
Based on the

results from two published literature studies of BAM via the
intraperitoneal route, BAM

is expected to cause olfactory toxicity at doses 3X higher than
dichlobenil.

3.5.15	 	Level of Concern for Margin of Exposure (Dichlobenil and BAM)

The target MOEs for occupational and residential exposure risk
assessments are as follows:

Route

	Duration

	Short-Term

(1-30 days)	Intermediate-Term

(1-6 Months)	Long-Term

(> 6 Months)

Occupational (Worker) Exposure

Dermal	100/1000a	100/1000	100/1000

Inhalation	100/1000	100/1000	100/1000

Residential (Non-Dietary) Exposure

Oral	1000/1000	1000/1000	1000/1000

Dermal	1000/1000	1000/1000	1000/1000

Inhalation	1000/1000	1000/1000	1000/1000

a MOEs expressed for dichlobenil/BAM

3.5.16	       Recommendation for Aggregate Exposure Risk Assessments

Estimation of aggregate risk is currently not required, because a common
toxicological effect across oral, dermal, and inhalation exposure
scenarios was not observed for either dichlobenil or BAM.

     Classification of Carcinogenic Potential

Dichlobenil was determined to be non-mutagenic in bacteria and mammalian
cells, as

well as non-clastogenic in several mammalian assays (in vitro and in
vivo).  The

carcinogenic potential of dichlobenil was evaluated for the second time
by the Health

Effects Division Carcinogenicity Peer Review Committee (CPRC) in 1995.
In a high-

dose carcinogenicity study in the hamster, a treatment-related increase
in liver adenomas

and combined adenomas/carcinomas was observed in males only at the
highest dose

tested.  However, dosing was considered excessive at this dose in both
sexes, based on

decreased body weight gains and severe hepatotoxicity.  In a second
carcinogenicity

study performed in hamsters at lower doses, no treatment-related
increases in the

incidence of any tumor type were observed.  Dosing was considered
adequate, based on

decreased body weight gains and hyperplasia in various tissues in both
sexes.  In a

combined chronic toxicity/carcinogenicity study in the rat, a
treatment-related increase in

the incidence of hepatocellular adenomas and combined
adenomas/carcinomas was

observed in females only at the highest dose tested.  Dosing was
considered adequate in

females, but excessive in males, at this dose.  Based on these data, the
CPRC classified

dichlobenil as a “Group C, possible human carcinogen” (former
system), and an RfD

approach to quantification of cancer risk was recommended.

BAM was determined to be non-mutagenic in bacteria and non-clastogenic
in an in vivo

mouse erythrocyte micronucleus assay.  Like dichlobenil, BAM also did
not induce

unscheduled DNA synthesis in mammalian cells.  The Agency is currently
reviewing

additional genotoxicity studies for BAM.  There was no evidence of
carcinogenicity in

the combined chronic toxicity/carcinogenicity study of BAM in the rat.
An increased

incidence of hepatocellular adenomas was observed at the high dose in
females only in

the study.  However, the statistical significance of the effect was
marginal (P=0.049),

dosing was considered adequate in the study, and the tumors were
non-cancerous.

However, since the carcinogenic potential of BAM was evaluated in only
one species,

HED considers the carcinogenic potential of BAM to be similar to that of
dichlobenil

(possible human carcinogen).  Therefore, an RfD approach to
quantification of cancer

risk is also warranted for BAM.

3.6	 	Endocrine disruption

EPA is required under the Federal Food, Drug, and Cosmetic Act (FFDCA),
as amended

by FQPA, to develop a screening program to determine whether certain
substances

(including all pesticide active and other ingredients) “may have an
effect in humans that

is similar to an effect produced by a naturally occurring estrogen, or
other such endocrine

effects as the Administrator may designate.”  Following
recommendations of its

Endocrine Disruptor and Testing Advisory Committee (EDSTAC), EPA
determined that

there was a scientific basis for including, as part of the program, the
androgen and thyroid

hormone systems, in addition to the estrogen hormone system.  EPA also
adopted

EDSTAC’s recommendation that the Program include evaluations of
potential effects in

wildlife. For pesticide chemicals, EPA will use the Federal Insecticide,
Fungicide, and

Rodenticide Act (FIFRA) and, to the extent that effects in wildlife may
help determine

whether a substance may have an effect in humans, FFDCA authority to
require the

wildlife evaluations.  As the science develops and resources allow,
screening of

additional hormone systems may be added to the Endocrine Disruptor
Screening Program

(EDSP).  When additional appropriate screening and/or testing protocols
being

considered under the Agency’s EDSP have been developed, dichlobenil or
its soil

metabolite, BAM, may be subjected to further screening and/or testing to
better

characterize effects related to endocrine disruption.  It is noted that
in the chronic dog

toxicity study with dichlobenil, delayed maturity of the uterus was
observed in all high-dose females.  A marked decrease in mean uterine
weight at the high dose confirmed this finding.  Ovarian weights were
also decreased in high-dose females, but no alterations were observed
microscopically.  These results are suggestive of modulation of the
female endocrine system; however, the dose at which these effects were
observed was forty times higher than that utilized for risk assessment,
i.e., the NOAEL.  The NOAEL utilized for risk assessment is therefore
considered protective of any potential endocrine modulation by
dichlobenil.  In addition, no other reproductive parameters were
affected in this or any other study in the database.  No evidence of
endocrine modulation was observed in any study with BAM.

4.0		Public Health and Pesticide Epidemiology Data

This is the function of the ORE assessor.  It would be interesting to
know if adverse nasal effects have been reported in human Ag workers
exposed to dichlobenil.

8.0		Cumulative Risk Characterization/Assessment

Dichlobenil produces a toxic metabolite (BAM) that is also produced by
chlorthiamid (2,6-dichlorothiobenzamide), and this should be considered.
 For information regarding EPA’s efforts to determine which chemicals
have a common mechanism of toxicity and to evaluate the cumulative
effects of such chemicals, see the policy statements released by EPA’s
Office of Pesticide Programs concerning common mechanism determinations
and procedures for cumulating effects from substances found to have a
common mechanism on EPA’s website at
http://www.epa.gov/pesticides/cumulative/.

10.0		Data Needs and Label Requirements

Toxicology

Guideline acute neurotoxicity screening battery (OPPTS 870.6200) with
2,6-dichlorobenzamide (BAM)

Guideline subchronic neurotoxicity screening battery (OPPTS 870.6200)
with 2,6-dichlorobenzamide (BAM)

A comparative study of olfactory toxicity by the oral route in neonates
and adults.  The registrant is encouraged to consult with the Agency to
discuss the protocol.

A DNT is reserved pending receipt and review of the acute and subchronic
neurotoxicity screening batteries

1 Calculated as follows: [(Concentration in mg/m3) x (m3 / 1000 L) x
(24,550 / MW) x (0.100 mg/kg/day / ppm for a young rat)], where MW=172.

 Calculated as follows: [(Concentration in mg/m3) x (m3 / 1000 L) x
(24,550 / MW) x (0.100 mg/kg/day / ppm for a young rat)], where MW=172.

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