UNITED
STATES
ENVIRONMENTAL
PROTECTION
AGENCY
WASHINGTON
D.
C.,
20460
OFFICE
OF
PREVENTION,
PESTICIDES
AND
TOXIC
SUBSTANCES
PC
Code:
031301
DP
Barcode:
D294453
Date:
February
7,
2006
MEMORANDUM
SUBJECT:
Revised
Ecological
Risk
Assessment
in
Support
of
the
Reregistration
Eligibility
Decision
on
DCNA
(
Dicloran)

TO:
James
Parker,
Chemical
Review
Manager
Special
Review
and
Reregistration
Division
Barbara
Madden,
Product
Manager
Registration
Division
FROM:
Cheryl
A.
Sutton,
Ph.
D.,
Environmental
Scientist
Christopher
J.
Salice,
Ph.
D.,
Biologist
Environmental
Risk
Branch
IV
Environmental
Fate
and
Effects
Division
(
7507c)

APPROVED
BY:
Elizabeth
Behl,
Branch
Chief
Environmental
Risk
Branch
IV
Environmental
Fate
and
Effects
Division
(
7507c)

The
Environmental
Fate
and
Effects
Division
(
EFED)
has
completed
its
revision
of
the
environmental
fate
and
ecological
risk
assessment
of
the
organochlorine
pesticide
DCNA
(
dicloran)
in
support
of
the
reregistration
eligibility
decision
on
DCNA
as
a
contact
fungicide
in
a
variety
of
food
and
non­
food
labeled
uses
(
and
three
proposed
new
uses).
The
risk
assessment
has
been
revised
to
reflect
the
additional
data
sent
in
by
the
registrant
during
the
error­
only
comment
period.
In
response
to
data
gaps
identified
in
the
environmental
fate
and
ecological
risk
assessment
of
DCNA
(
DP
Barcode
D313887;
dated
7/
20/
05),
the
registrant
submitted
one
environmental
fate
(
aerobic
aquatic
metabolism)
and
four
ecological
effect
studies
for
evaluation.
The
ecological
effects
studies
included
a
rainbow
trout
(
Oncorhynchus
mykiss)
juvenile
growth
study,
a
Daphnia
magna
life
cycle
study,
a
sediment
toxicity
study
of
midge
(
Chironomus
riparius)
larvae,
and
an
aquatic
plant
(
Scendesmus
subspicatus)
toxicity
study.
As
a
result
of
the
new
data,
new
surface
water
estimated
environmental
concentrations
(
EEC)
were
determined
and
revised
RQs
were
calculated.
Additionally,
estimated
concentrations
in
sediment
pore
water
were
determined
and
RQs
were
calculated
using
the
newly
submitted
sediment
toxicity
data.

Estimated
environmental
concentrations
for
both
aquatic
and
terrestrial
exposure
assessments
were
based
on
parent
DCNA
only.
The
revised
document
comprises
the
Level
1
screening
assessment
of
the
environmental
fate
and
ecological
effects
for
the
pesticide
DCNA.
It
represents
a
national
assessment,
although
the
majority
(
99%)
of
DCNA
usage
is
in
California
and
the
Pacific
Northwest.
Modeled
uses
include
labeled
uses
on
lettuce,
grapes,
potatoes,
snapbeans,
and
onions;
and
proposed
uses
on
peanuts
and
carrots.
Modeling
­
2­

results
for
head
lettuce
in
California
can
serve
as
surrogate
modeling
results
for
both
celery
(
a
major
use)
and
radicchio
(
a
new
use),
which
are
in
the
same
crop
group
(
Group
04)
as
head
lettuce.
Application
rates
and
use
patterns
modeled
have
not
been
changed
from
the
previous
risk
assessment
(
DP
Barcode
D313887).

Based
on
a
deterministic
screening­
level
assessment
of
environmental
exposure
and
biological
effects
data
for
DCNA,
as
reflected
in
the
revised
RQ
values,
potential
risks
associated
with
DCNA
usage
are
indicated
for
freshwater
fish
and
amphibians
(
acute
endangered
species);
birds
and
reptiles
(
acute,
acute
endangered
species,
chronic);
and
mammals
(
acute
endangered
species,
chronic).
There
were
no
LOC
exceedences
indicating
potential
acute
or
acute
endangered
species
risks
to
either
freshwater
or
estuarine/
marine
invertebrates,
nor
acute
risks
to
mammals.
Chronic
risk
LOCs
were
not
exceeded
for
freshwater
fish
and
invertebrates.
However,
there
is
uncertainty
associated
with
the
freshwater
fish
chronic
toxicity
study
which
did
not
follow
guidelines;
a
guideline
freshwater
fish
chronic
toxicity
study
is
still
required.
The
potential
for
chronic
risks
to
estuarine/
marine
fish
and
invertebrates
is
unknown
because
useable
ecotoxicity
data
were
not
submitted.
Similarly,
ecotoxicity
data
were
not
submitted
for
aquatic
vascular
or
for
terrestrial
or
semi­
aquatic
plants,
so
potential
risks
to
these
taxa
could
not
be
assessed.
In
the
absence
of
suitable
toxicity
data,
risks
are
assumed.
Hence
for
DCNA,
chronic
risks
are
assumed
for
estuarine/
marine
fish
and
invertebrates
and
risks
are
also
assumed
from
aquatic
vascular
and
terrestrial/
semi­
aquatic
plants.
The
risk
assessment
for
DCNA
remains
incomplete,
because
the
body
of
submitted
toxicity
data
is
still
incomplete.
Detailed
information
on
the
data
gaps
are
presented
below
in
Tables
1
and
2.
­
3­

Table
1.
Status
of
environmental
fate
data
adequacy/
needs
for
DCNA.

Guideline
#
Data
Requirement
Are
Data
Adequate
for
Risk
Assessme
nt?
MRID
#'
s
Study
Classification
161­
1
835.2120
Hydrolysis
yes
Acc.
No.
253963
Acceptable
161­
2
835.2240
Photodegradation
in
Water
yes
43891901
40508809
Acceptable
Unacceptable
161­
3
835.2410
Photodegradation
on
Soil
yes
43893601
40508810
Acceptable
Unacceptable
161­
4
835.2370
Photodegradation
in
Air
 

162­
1
835.4100
Aerobic
Soil
Metabolism
yes
408948011
00086942
Acceptable
Supplemental
162­
2
835.4200
Anaerobic
Soil
Metabolism
yes
408948011
Acceptable
162­
3
835.4400
Anaerobic
Aquatic
Metabolism
yes
438665011
Acceptable
162­
4
835.4300
Aerobic
Aquatic
Metabolism
no
462160011
46657101
Unacceptable
Acceptable
163­
1
835.1240
835.1230
Leaching­
Adsorption/
Desorption
yes
40538202
40538201
43809001
40863001
00065859
Acceptable
Acceptable
Supplemental
Unacceptable
Unacceptable
163­
2
835.1410
Laboratory
Volatility
waived
(
4/
6/
90)

164­
1
835.6100
Terrestrial
Field
Dissipation
Not
Required
44414201
40583101
00086953
&
00086955
00082668
Acceptable
Unacceptable
Unacceptable
Unacceptable
164­
2
835.6200
Aquatic
Field
Dissipation
 
 
NA
164­
3
835.6300
Forestry
Dissipation
 
 
NA
164­
4
835.6400
Combination
Products
and
Tank
Mixes
Dissipation
 
 
NA
­
4­

165­
4
850.1730
Accumulation
in
Fish
yes
43782001
40508808
Acceptable
Supplemental
165­
5
850.1950
Accumulation
 
Aquatic
Non­
target
Organisms
 
 
NA
166­
1
835.7100
Groundwater
 
Small
Prospective
yes
45237401
In
Review
201­
1
840.1100
Droplet
Size
Spectrum
202­
1
840.1200
Drift
Field
Evaluation
1A
single
document,
MRID
40894801,
contains
both
the
aerobic
and
anaerobic
soil
metabolism
studies.
­
5­

Table
2.
Status
of
ecological
effects
data
adequacy/
needs
for
DCNA.

Guideline
#
Data
Requirement
MRID
#'
s
Study
Classification
Are
the
data
adequate
for
risk
assessment?

71­
1
Avian
acute
oral
LD50
Bobwhite
quail
Mallard
duck
437551­
01
405831­
03
Acceptable
Invalid
yes
no
71­
2
Avian
subacute
dietary
LC50
Bobwhite
quail
Mallard
duck
405088­
12
431155­
01
405088­
11
431155­
02
Supplemental
Acceptable
Supplemental
Acceptable
no
yes
no
yes
71­
4
Avian
reproduction
bobwhite
quail
mallard
duck
462189­
00
NS
In
Review
­­
In
Review
no
72­
1
Freshwater
fish
acute
LC50
Rainbow
trout
Bluegill
sunfish
00096064
00096058
Acceptable
Acceptable
yes
yes
72­
2
Freshwater
invertebrate
acute
LC50
(
Daphnia
magna)
405831­
02
Acceptable
yes
72­
3a
Estuarine/
marine
fish
acute
LC50
(
Sheepshead
minnow)
NS
­­
no
72­
3b
Estuarine/
marine
acute
invertebrate
LC50
(
mysid)
NS
­­
no
72­
3c
Estuarine/
marine
acute
invertebrate
LC50
(
mollusc)
00087031
Supplemental
yes
72­
4a
Freshwater
fish
early
life
stage
(
Rainbow
trout)
NS
­­
no
72­
4b
Freshwater
invertebrate
life
cycle
(
Daphnia
magna)
466571­
03
Supplemental
yes
72­
4d
Estuarine/
marine
life
cycle
(
mysid)
NS
­­
no
72­
5
Freshwater
fish
full
life
cycle
(
Fathead
minnow)
NS
­­
no
141­
1
Acute
honeybee
contact
00036935
Acceptable
yes
Nonguideline
Earthworm
Acute
NS
­­
Not
Required
­
6­

Nonguideline
Sediment
Test
w/
Chironomus
sp.
466571­
04
 
no
122­
1
Tier
I
Terrestrial
Plant
NS
 
no
123­
2
Acute
nonvascular
plant
466571­
05
Acceptable
yes
81­
1
rat
acute
oral
toxicity
00086879
00064581
Unacceptable
Supplemental
no
yes
83­
4
rat
2­
generation
reproduction
444141­
01
Acceptable
yes
NS
=
not
submitted
