APPENDIX
B
TIER
I
DRINKING
WATER
ASSESSMENT
UNITED
STATES
ENVIRONMENTAL
PROTECTION
AGENCY
WASHINGTON,
D.
C.
20460
OFFICE
OF
PREVENTION,
PESTICIDES,
AND
TOXIC
SUBSTANCES
PC
Code:
056502
DP
BARCODE:
291286
MEMORANDUM
November
12,
2003
SUBJECT:
Pentachloronitrobenzene:
Tier
I
Drinking
Water
EDWCs
for
Use
in
the
Human
Health
Risk
Assessment.

TO:
Mohsen
Sahafeyan,
Chemist
RRB2/
HED
(
7509C)

FROM:
Cheryl
A.
Sutton,
Ph.
D.
Environmental
Scientist
ERBIV/
EFED
(
7507C)

THRU:
R.
David
Jones,
Ph.
D.,
Senior
Agronomist
ERBIV/
EFED
(
7507C)

Elizabeth
Behl,
Branch
Chief
ERBIV/
EFED
(
7507C)

This
memo
summarizes
the
Tier
I
estimated
drinking
water
concentrations
(
EDWC)
for
pentachloronitrobenzene
[
PCNB;
plus
the
degradate
pentachloroaniline
(
PCA),
as
described
below]
in
surface
water
and
in
groundwater
for
use
in
the
human
health
risk
assessment.
The
EDWC's
are
summarized
in
Table
1.
Because
the
surface
water
EDWC
values
(
as
estimated
by
FIRST)
are
controlled
by
the
solubility
of
PCNB
(
440

g
L­
1)
rather
than
by
the
degradation
rate,
there
is
no
difference
the
in
EDWC
whether
PCA
is
included
in
the
estimate
or
not.
This
may
not
hold
if
more
refined
assessments
with
PRZM
and
EXAMS
are
done.
EFED
used
the
screening
model
FIRST
(
FQPA
Index
Reservoir
Screening
Tool)
to
calculate
the
surface
water
EDWC's
and
used
the
screening
model
SCI­
GROW
(
Screening
Concentrations
in
Ground
Water)
to
calculate
the
groundwater
EDWC.
Because
PCNB
is
a
registered
chemical
already
in
use,
a
search
for
monitoring
data
was
conducted;
the
results
are
discussed
in
a
separate
section
below.
Because
monitoring
data
for
PCNB
are
scarce
and
of
limited
value
in
terms
of
this
assessment,
they
are
presented
only
for
their
qualitative
value;
they
were
not
used
quantitatively
in
the
drinking
water
assessment.

In
response
to
a
decision
made
by
the
MARC
committee
(
27
May
2003;
Final
Decision),
the
EFED
scientist
was
to
conduct
the
drinking
water
assessment
to
account
for
the
parent
compound
plus
two
PCNB
degradates
considered
to
be
residues
of
concern,
pentachloroaniline
(
PCA)
and
pentachlorophenol
(
PCP).
Because
PCP
is
a
known
carcinogen,
it
will
be
considered
separately
in
2
this
assessment.
Because
PCP
was
not
monitored
and/
or
detected
in
most
of
the
submitted
guideline
studies,
the
evaluation
of
the
compound
in
terms
of
its
presence
in
drinking
water
as
a
result
of
PCNB
use
will
be
qualitative.
To
account
for
the
degradate
PCA,
aerobic
soil
metabolism
half­
lives
determined
for
the
parent
compound
in
the
guideline
studies
were
recalculated
using
concentration
data
for
the
parent
compound
plus
PCA.
Because
separate
aqueous
photolysis
data
were
not
available
for
PCA,
and
the
compound
was
not
detected
in
the
irradiated
solutions
initially
containing
the
parent
compound,
the
photolysis
half­
life
used
in
the
modeling
was
calculated
using
parent
compound
concentration
data
only.
The
lack
of
information
on
the
photolysis
rate
of
PCA
comprises
a
small
uncertainty
surrounding
the
surface
water
EDWCs.
For
the
input
parameter
values
for
soil
adsorption
(
K
oc
in
SCI­
GROW
and
K
d
in
FIRST),
the
reviewer
used
the
soil
adsorption
coefficients
determined
only
for
the
parent
compound.
Based
on
submitted
data,
however,
the
mobility
of
PCA
is
similar
to
that
of
the
parent
compound,
in
that
both
compounds
are
generally
expected
to
adsorb
to
soil
and
organic
matter
and
have
a
low
leaching
potential.

In
general,
PCNB
is
a
persistent,
volatile
compound
that
will
be
immobile
in
most
soils,
but
may
have
slight
or
even
moderate
mobility
in
coarser
(
sandy)
soils,
particularly
those
that
are
low
in
organic
matter.
While
PCNB
is
expected
to
be
persistent
in
aerobic
environments,
it
is
microbially
degraded
more
rapidly
(
DT
50'
s
of
<
30
days)
in
anaerobic
environments.
It
is
stable
to
hydrolysis
and
is
effectively
stable
to
photodegradation
on
soil,
but
appears
(
based
on
two
submitted
studies)
to
photodegrade
fairly
rapidly
in
water,
with
half­
lives
on
the
order
of
a
few
days
or
less.
(
While
evidence
of
aqueous
photodegradation
of
PCNB
was
not
found
in
the
literature,
EFED
found
the
submitted
studies
acceptable
and,
therefore,
used
the
half­
life
values
determined
in
those
studies.)
In
field
studies,
the
compound
has
been
shown
to
dissipate
more
rapidly
in
the
plots
in
which
the
pesticide
was
not
incorporated,
with
a
half­
life
range
of
39­
57
days
versus
a
half­
life
range
of
128­
324
days
for
plots
with
incorporated
PCNB.
The
major
degradates
of
PCNB
in
the
environment
are
PCA
and
pentachlorothioanisole
(
PCTA);
minor
degradates
are
pentachlorothioanisole
sulfoxide
(
PCTASO),
pentachlorothioanisole
sulfone
(
PCTASO
2),
and
pentachlorobenzene
(
PCB),
which
is
also
present
as
an
impurity
along
with
hexachlorobenzene
(
HCB).
While
PCP
was
detected
in
two
of
the
submitted
studies,
there
is
not
sufficient
evidence
(
either
from
the
submitted
data
or
from
published
literature,
as
discussed
later
in
this
memo)
that
the
compound
will
routinely
be
formed
from
PCNB
in
the
environment.

Table
1.
Tier
I
EDWCs
for
drinking
water
risk
assessment.

Surface
water
drinking
water
sources
acute:
440
ug/
L
(
ppb)
1
chronic:
440
ug/
L
(
ppb)

Groundwater
drinking
water
sources
30.6
ug/
L
(
ppb)
2
1Surface
water
EDWC's
(
acute
and
chronic)
are
based
on
PCNB
use
on
turf
at
32.67
lb
a.
i./
A/
application
in
two
applications
(
total
application
rate
of
65.34
lb
a.
i./
A.
Note
that
440
ppb
is
the
aqueous
solubility
limit
of
PCNB
at
25
oC.
2Groundwater
EDWC's
are
based
on
PCNB
use
on
bulb
crops
at
213.4
lb
a.
i./
A/
application
in
a
single
application.

Estimated
Drinking
Water
Concentrations
For
the
surface
water
and
groundwater
assessments,
the
application
rates
for
turf
(
2
applications
of
32.67
lb
a.
i./
A/
application),
peanuts
(
2
applications
of
10
lb
a.
i./
A/
application),
3
cole
crops
(
1
application
of
30
lb
a.
i./
A),
potatoes
(
1
application
of
25
lb
a.
i./
A)
and
bulb
crops
(
1
application
of
213.4
lb
a.
i./
A)
were
initially
used,
which
represent
the
highest
annual
application
rates
on
the
labels
(
as
presented
in
the
Use
Closure
Memo
for
PCNB
Reregistration
of
1/
23/
03,
amended
6/
23/
03)
for
soil
or
foliar
applications
of
PCNB.
Seed
treatment
usage
rates
were
considered
(
after
conversion
to
field
application
rates
by
multiplying
by
the
typical
seeding
rates
for
each
crop;
rates
were
obtained
from
Appendix
V
of
EFED's
9/
12/
03
Ecological
Risk
Assessment
for
the
Carboxin
Reregistration
Elegibility
Decision),
but
did
not
result
in
field
application
levels
greater
than
those
for
soil
and
foliar
applications.
The
soil
drench
application
scenario
(
applicable
to
many
crops)
was
modeled
to
determine
preliminary
EDWC's
for
such
uses.
While
these
values
are
reported
here
(
in
a
separate
table),
they
are
to
be
considered
preliminary
values
and
should
not
be
used
in
the
human
health
risk
assessment
at
this
time.
Prior
to
a
final
determination
of
EDWC's
associated
with
a
soil
drench
use,
it
is
necessary
that
EFED
obtain
additional
information
from
the
registrants
regarding
this
use
pattern.
A
summary
of
the
model
input
parameter
values
used
in
FIRST
to
model
soil
and
foliar
applications
is
presented
in
Table
2.
The
FIRST
output
file
is
located
in
Attachment
1.
A
summary
of
the
model
input
parameter
values
used
in
SCI­
GROW
to
model
soil
and
foliar
applications
is
presented
in
Table
3.
The
SCI­
GROW
output
file
is
located
in
Attachment
2.
A
table
of
the
source
data
used
to
determine
input
parameter
values
is
located
in
Attachment
3.

FIRST
(
v1.0)
is
a
screening­
level
model
designed
to
estimate
the
pesticide
concentrations
found
in
surface
water
for
use
in
drinking
water
assessments.
The
model
provides
upper
bound
estimates
of
environmental
concentrations
(
acute
and
chronic)
in
surface
water
drinking
water
sources
(
untreated)
that
might
occur
following
the
use
of
a
pesticide.
FIRST
uses
basic
environmental
fate
data
and
pesticide
label
use
and
application
information
to
estimate
the
EECs
following
the
treatment
of
a
10­
hectare
field
with
subsequent
runoff
into
a
reservoir
(
an
Index
Reservoir,
based
on
Shipman
City
Lake
in
Illinois,
a
13­
acre
lake
9­
feet
deep
with
a
watershed
area
of
427
acres
or
172.8
hectares)
that
undergoes
two
full
turnovers
annually.
FIRST
also
uses
a
Percent
Cropped
Area
(
PCA)
factor
to
adjust
for
the
area
within
the
watershed
that
is
planted
to
the
modeled
crop.
In
the
model,
a
single
runoff
event
occurs
two
days
after
the
last
application
and
can
move
a
maximum
of
8%
of
the
applied
pesticide
into
the
reservoir,
with
the
amount
dependent
on
the
degradation
and
adsorption
of
the
pesticide
which
occurs
in
the
field
prior
to
the
event,
any
incorporation
of
the
pesticide
at
the
time
of
application,
and
the
PCA.
The
model
also
accounts
for
degradation
and
binding
to
sediment
which
may
occur
in
the
reservoir
following
the
runoff
event.
Spray
drift
(
resulting
in
direct
deposition
of
the
pesticide
into
the
reservoir
or
indirect
loading
from
spray
drift
landing
on
the
feeding
stream)
in
the
model
is
equivalent
to
16%
of
the
applied
for
aerial
application,
6.3%
for
orchard
air
blast
application,
and
6.4%
for
other
ground
spray
application.

SCI­
GROW2
is
a
regression­
based,
Tier
1
screening
model
that
provides
a
groundwater
exposure
value
to
be
used
in
determining
the
potential
risk
to
human
health
from
drinking
water
contaminated
with
the
pesticide.
SCI­
GROW2
estimates
likely
groundwater
concentrations
if
the
pesticide
is
used
at
the
maximum
allowable
rate
in
areas
where
groundwater
is
vulnerable
to
contamination.
Characteristics
of
such
vulnerable
areas
include
high
rainfall,
rapidly
permeable
4
soil,
and
a
shallow
aquifer.
In
most
cases,
a
large
majority
of
the
use
area
will
have
groundwater
that
is
less
vulnerable
to
contamination
than
the
areas
used
to
derive
the
SCI­
GROW2
estimate.

EFED
recommends
that
the
acute
EDWC
to
be
used
in
the
human
health
risk
assessment
for
surface
water
is
440
ppb,
based
on
the
use
of
PCNB
on
turf
at
an
application
rate
of
32.67
lb
a.
i./
A/
application
for
two
applications
with
an
application
interval
of
21
days
(
total
application
rate
of
65.3
lb
a.
i./
A).
It
is
noted
that
for
all
of
the
aforementioned
crops
modeled
with
soil/
foliar
applications
(
with
total
maximum
application
rates
ranging
from
20
to
213.4
lb
a.
i./
A),
the
same
acute
EDWC's
(
i.
e.,
440
ppb)
were
obtained.
Note,
also,
that
the
value
"
440
ppb"
is
the
aqueous
solubility
limit
of
the
parent
compound
at
25
oC.
EFED
recommends
that
the
chronic
EDWC
to
be
used
in
the
drinking
water
assessment
for
surface
water
is
440
ppb,
also
based
on
the
use
of
PCNB
on
turf,
as
described
previously.
While
the
use
of
PCNB
on
bulb
crops
at
an
application
rate
of
213.4
lb
a.
i./
A/
application
with
a
single
application
and
no
incorporation
resulted
in
the
same
chronic
EDWC
for
surface
water
of
440
ppb,
the
same
use
(
i.
e.,
bulbs)
only
with
incorporation
to
6
inches
resulted
in
a
lower
chronic
EDWC
of
328.6
ppb.
For
the
purposes
of
comparison,
EFED
determined
the
acute
and
chronic
surface
water
EDWC's
for
parent
PCNB
only
(
without
including
PCA),
using
the
turf
application
scenario.
The
EDWC's
for
parent
only
were
440
ppb
for
both
acute
and
chronic
exposures,
indicating
that
the
inclusion
of
PCA
did
not
have
an
apparent
effect
on
the
surface
water
EDWC's,
as
they
were
more
significantly
affected
by
the
aqueous
solubility
limit
of
the
compound.

EFED
recommends
that
the
EDWC
to
be
used
in
the
human
health
risk
assessment
for
groundwater
is
30.6
ppb,
based
on
the
use
of
PCNB
on
bulb
crops
at
an
application
rate
of
213.4
lb
a.
i./
A,
applied
in
a
single
application.
For
the
purposes
of
comparison,
EFED
determined
the
groundwater
EDWC
for
parent
PCNB
only
(
without
including
PCA),
using
the
bulb
application
scenario.
The
EDWC
for
parent
only
was
13.0
ppb,
indicating
that
the
inclusion
of
PCA
did
have
an
effect
on
the
groundwater
EDWC.
5
Table
2.
FIRST
(
v1.0)
input
parameter
values
and
results
for
PCNB
applied
to
various
crops.

Parameter
Value
Application
Rate
(
lb
a.
i./
A)
turf:
32.67
potatoes:
25
peanuts:
10
bulb
crops:
213.4
cole
crops:
30
Number
of
Applications
turf:
2
potatoes:
1
peanuts:
2
bulb
crops:
1
cole
crops:
1
Interval
between
Applications
(
days)
turf:
21
potatoes:
NA
peanuts:
30
bulb
crops:
NA
cole
crops:
Not
Applicable
(
NA)

Soil
Partition
Coefficient
(
K
d;
mL/
g)
15.5
(
MRID
41648201;
lowest
non­
sand
K
d)

Aerobic
Soil
Metabolism
Half­
life
(
days)
t
1/
2
=
1555
days
(
parent
plus
PCA)
(
source
data
from
MRID's
42911902,
41384501,
41713202,
42112801)
1
Wetted
in?
No
Depth
of
Incorporation
(
inches)
turf:
0
potatoes:
0
peanuts:
0
bulb
crops:
0;
6
cole
crops:
0
Method
of
Application
turf:
ground
application
of
granular
peanuts:
ground
application
of
granular
cole
crops:
ground
spray
(
broadcast)
potatoes:
ground
spray
(
broadcast)
bulb
crops:
ground
spray
(
broadcast);
granular
Percent
Cropped
Area
0.87
(
all
crops
modeled
here)

Solubility
in
Water
(
mg/
L
or
ppm)
0.44
Aerobic
Aquatic
Metabolism
Half­
life
(
days)
t
1/
2
=
3110
days
(
parent
plus
PCA)
1
(
source
data
from
MRID's
42911902,
41384501,
41713202,
42112801)
(
input
value
is
two
times
the
aerobic
metabolism
half­
life
input
value)

Hydrolysis
Half­
life
@
pH
7
(
days)
stable
Aquatic
Photolysis
Half­
life
@
pH5
(
days)
1.83
FIRST
Results
(
Estimated
Drinking
Water
Concentrations
for
surface
water)
Acute
Concentration
(
ppb):
4402
(
all
crops)
Chronic
Concentration
(
ppb):
turf:
440.0
peanuts:
183.6
cole
crops:
301.4
potatoes:
251.2
bulb
crops:
440.0;
328.63
1For
the
purposes
of
the
drinking
water
assessment,
half­
lives
were
recalculated
to
account
for
the
parent
plus
the
degradate
PCA.
The
aerobic
soil
metabolism
half­
life
used
in
the
models
represents
the
90th
percentile
of
the
upper
confidence
bound
on
the
mean
half­
life
for
two
soils.
The
aerobic
aquatic
metabolism
half­
life
was
determined,
in
the
absence
of
study
data,
by
mulitiplying
the
aerobic
soil
metabolism
half­
life
model
input
value
by
two
to
account
for
the
uncertainty
associated
with
a
lack
of
true
aquatic
metabolism
study
data.
2Note
that
440
ppb,
the
acute
concentration
for
all
scenarios
modeled,
is
the
aqueous
solubility
limit
for
PCNB
at
25
oC.
3Because
FIRST
does
not
allow
directly
for
incorporation
of
a
non­
granular
formulation
(
as
is
done
for
this
usage),
the
EDWC
was
also
determined
for
this
crop
(
2nd
value
reported)
using
a
granular
formulation
incorporated
to
6
inches
to
represent
the
use
of
either
a
granular
OR
a
non­
granular
formulation
(
F,
WP
or
WSP)
incorporated
to
6
inches.
The
first
value
reported
corresponds
to
a
use
scenario
with
no
incorporation.
6
Table
3.
SCI­
GROW2
input
parameter
values
and
results
for
PCNB
applied
to
various
crops
by
soil
or
foliar
applications
only.

Parameter
Value
Maximum
Application
Rate
(
lb
a.
i./
A/
application)
turf:
32.67
peanuts:
10
cole
crops:
30
potatoes:
25
bulb
crops:
213.4
Maximum
Number
of
Applications
per
Year
turf:
2
(
21­
day
interval)
peanuts:
2
(
30­
day
interval)
cole
crops:
1
potatoes:
1
bulb
crops:
1
Aerobic
Soil
Metabolism
Half­
life
(
days)
t
1/
2
=
750.5
days
(
parent
plus
PCA;
average
of
two
values)
1
Organic
Carbon
Partition
Coefficient
(
K
oc)
1588
(
lowest
value
of
four;
based
on
parent
compound
only)
(
MRID
41648201)

Results
(
Estimated
Drinking
Water
Concentrations
for
groundwater,
in
ppb)
turf:
9.38
peanuts:
2.87
cole
crops:
4.31
potatoes:
3.59
bulb
crops:
30.6
1For
the
purposes
of
the
drinking
water
assessment,
half­
lives
were
recalculated
to
account
for
the
parent
plus
the
degradate
PCA,
as
requested
by
the
MARC.

Preliminary
EDWC's
for
a
Soil
Drench
Use
Scenario
To
allow
for
a
determination
of
EDWC's
for
all
of
the
potential
label
uses
of
PCNB,
the
soil
drench
application
scenario
(
applicable
to
many
crops)
was
modeled
to
determine
preliminary
EDWC's
for
such
uses.
Although
the
application
scenario
is
reported
as
a
soil
drench
use
on
beans
(
dry
type),
a
soil
drench
use
on
multiple
other
crops
with
the
same
application
rate
(
i.
e.,
40.84
lb
a.
i./
A/
application)
will
yield
the
same
values.
The
values
are
reported
in
Table
4
are
to
be
considered
preliminary
values
and
should
not
be
used
in
the
human
health
risk
assessment
at
this
time.
Prior
to
a
final
determination
of
EDWC's
associated
with
a
soil
drench
use,
it
is
necessary
that
EFED
obtain
additional
information
from
the
registrants
on
this
use
pattern,
particularly
with
regard
to
drenching
practices,
time
between
drench
and
transplant,
number
of
treatments,
estimated
amount
of
pesticide/
formulated
product
not
retained
in
the
drenched
container,
and
planting
densities
for
transplants
in
the
field.
Please
note
that
the
preliminary
values
were
determined
with
a
usage
scenario
which
included
a
single
application
of
the
pesticide.
Although
the
label
appears
to
allow
for
two
applications
(
with
a
28­
day
interval)
per
growing
season
at
this
rate,
it
is
unclear
as
to
when
the
applications
would
occur
relative
to
the
transplant
to
the
field.
Thus,
at
this
time,
EFED
utilized
a
single
application
in
the
use
scenario.
7
Table
4.
Tentative
Tier
I
EDWCs
for
drinking
water
based
on
a
soil
drench
use
scenario.

Surface
water
drinking
water
sources
acute:
207.3
ug/
L
(
ppb)
1
chronic:
62.9
ug/
L
(
ppb)

Groundwater
drinking
water
sources
5.9
ug/
L
(
ppb)

1Surface
water
and
groundwater
EDWC's
are
based
on
PCNB
use
on
beans
(
dry­
type)
at
40.84
lb
a.
i./
A/
application
in
a
single
application
.
Note
that
this
application
rate
is
the
same
as
that
used
for
multiple
other
crops
with
a
soil
drench
application
usage.
Note
also
that
440
ppb
is
the
aqueous
solubility
limit
of
PCNB
at
25
oC.

Monitoring
Data
NAWQA
monitoring
data
are
not
available.
Based
on
information
contained
in
the
USEPA's
Pesticides
in
Ground
Water
Database,
A
Compilation
of
Monitoring
Studies:
1971­
1991,
National
Summary,
PCNB
is
not
found
in
groundwater
at
significant
levels
or
frequencies.
In
sampling
of
1708
wells,
only
three
detections
of
PCNB
occurred,
at
a
range
of
0.008
 
0.275

g/
L.
Sampled
wells
which
did
not
contain
measurable
levels
of
PCNB
included
459
wells
in
California,
71
in
Maine,
649
in
Minnesota,
263
in
Mississippi,
10
in
Oregon
and
188
in
Texas.
However,
there
is
no
related
information
available
with
regard
to
whether
the
monitoring
sites
corresponded
with
PCNB
use
sites
or
times
of
usage.
Updated
monitoring
data
from
STORET
are
not
available;
it
is
no
longer
possible
to
query
either
the
historical
database
(
in
the
Legacy
Data
Center)
or
the
new
database
(
Modernized
STORET)
to
obtain
all
detections
of
a
specific
compound.

To
supplement
the
monitoring
data
available
to
EFED
in­
house,
a
literature
search
was
conducted
to
obtain
published
information
(
generally
post­
1990
only)
on
the
occurrences
of
PCNB
and
its
degradates
in
the
aquatic
and
terrestrial
environments;
information
on
the
former
are
included
below.
PCNB
and
its
major
degradates
PCA
and
PCTA
have
not
been
detected
frequently
in
North
America.
The
presence
of
PCA
and
PCTA
in
the
environment
are
most
likely
a
result
of
the
use
of
PCNB.
Detections
of
the
potential
degradate
PCP
in
the
environment
cannot
necessarily
be
attributed
to
its
existence
as
a
degradate
of
PCNB,
but
are
most
likely
a
result
of
its
use
as
a
pesticide
(
wood
preservative).
Similarly,
detections
of
the
degradate
(
and
impurity
in
PCNB)
PCB
in
the
environment
are
most
likely
a
result
of
its
existence
as
a
byproduct
in
the
manufacture
of
other
compounds
or
as
a
degradate
of
hexachlorobenzene
(
HCB),
and
its
industrial
uses.

In
a
groundwater
monitoring
study
of
18
wells
in
three
counties
in
California
(
July
1994
 
1995),
PCNB
was
not
detected
(
California
EPA,
1995).
In
a
review
of
multiple
studies
in
which
sampling
was
conducted
in
surface
water
and/
or
groundwater
at
golf
courses,
PCNB
was
monitored
in
surface
water
in
an
unspecified
number
of
studies,
but
was
not
detected
(
Cohen
et
al.,
1999).

The
degradates
PCA,
PCB
and
PCP
were
monitored
in
the
Mississippi
River
and
many
of
its
tributaries
(
Illinois,
Missouri,
Ohio,
Arkansas,
White,
and
Yazoo
Rivers;
Rostad
et
al.,
1993).
PCA
was
detected
in
the
surface
waters
at
multiple
locations,
at
concentrations
of
0.018­
0.055
ng/
L.
PCB
was
detected
in
the
Mississippi
River
and
two
of
its
main
tributaries,
but
was
not
likely
a
result
of
PCNB
use.
Its
presence
was
attributed
to
its
existence
as
a
degradate
of
HCB,
as
suggested
by
the
concentration
profiles
of
the
two
compounds.
PCP
was
not
found
in
any
of
the
surface
water
8
samples.

In
summary,
monitoring
data
on
PCNB
are
somewhat
scarce
and/
or
incomplete
information
is
available.
As
such,
the
data
may
be
taken
at
face
value,
but
are
not
substantial
enough
to
quantitatively
incorporate
into
the
drinking
water
assessment.
Additionally,
the
data
have
limitations
in
that
it
is
not
clear
in
most
cases
whether
the
water
bodies/
wells
monitored
correspond
with
or
were
even
targeted
to
correspond
with
PCNB
usage
in
terms
of
location
and/
or
time.

Pentachlorophenol
It
was
decided
by
the
MARC
committee
that
both
pentachloroaniline
(
PCA)
and
pentachlorophenol
(
PCP)
were
both
PCNB
degradates
of
concern
in
water.
Thus,
the
drinking
water
assessment
must
take
into
account
these
degradates
in
addition
to
the
parent
compound.
The
degradate
PCA
was
accounted
for
by
the
recalculation
of
the
parent
half­
lives,
as
described
previously
in
this
memo.
As
aforementioned,
the
degradate
PCP,
a
known
carcinogen,
must
be
considered
independently
of
PCNB
and
PCA.
In
the
submitted
guideline
studies,
pentachlorophenol
(
PCP)
was
detected
as
a
degradate
of
PCNB
in
only
two
of
the
studies,
an
anaerobic
soil
metabolism
study
and
a
terrestrial
field
dissipation
study.
In
the
anaerobic
soil
metabolism
study,
PCP
was
first
detected
in
the
soil,
at
0.28
ppm,
immediately
after
the
induction
of
anaerobic
conditions
at
30
days,
and
was
0.33
ppm
at
90
days
(
60
days
postflooding);
in
the
water
phase,
PCP
was
0.048
ppm
at
60
days
and
0.037
ppm
at
90
days.
[
It
is
noted
that,
given
current
EFED
modeling
requirements,
data
from
aerobic
and
anaerobic
aquatic
metabolism
studies
are
generally
considered
more
useful
than
data
from
the
anaerobic
soil
metabolism
studies.]
In
the
terrestrial
field
dissipation
study
in
which
PCP
was
detected,
the
compound
was
detected
immediately
after
application
at
0.022
ppm,
increased
with
time
to
a
maximum
of
0.161
ppm
by
day
16,
then
decreased
to
0.008
ppm
by
day
60,
and
was
below
the
limit
of
quantification
(
LOQ;
0.005
ppm)
by
120
days.
The
lack
of
detection
of
PCP
in
the
second
submitted
anaerobic
soil
metabolism
study
and
the
other
seven
field
dissipation
studies
does
not
indicate
that
the
compound
wasn't
present;
it
was
simply
not
monitored
in
those
studies.
In
a
single
aerobic
soil
metabolism
study
in
which
PCP
was
monitored,
the
compound
was
not
detected.

As
submitted
data
on
PCP
(
specifically,
as
a
degradate
of
PCNB)
are
lacking,
the
treatment
of
PCP
in
EFED's
Tier
I
assessment
must
be
qualitative
in
nature.
The
conclusions
presented
here
were
drawn
mainly
from
information
obtained
from
the
published
literature,
as
cited
where
appropriate.
Essentially,
evidence
that
PCP
is
formed
from
PCNB
during
microbial
degradation
in
soil
has
been
found
in
the
literature,
but
the
weight
of
evidence
is
not
substantial.
EFED
has
indicated
to
SRRD
that
additional
data
on
the
microbial
metabolism
of
PCNB
in
both
aerobic
and
anaerobic
soil/
water
systems
are
necessary
for
a
more
complete
evaluation
of
the
risks
(
particularly
with
regard
to
PCP)
associated
with
the
use
of
PCNB.

PCP
has
been
reported
to
be
a
"
major"
degradate
of
PCNB
when
the
compound
is
microbially
metabolized
in
soil
(
Murthy
&
Kaufman,
1978;
Motoyama
et
al.,
2001).
However,
the
term
"
major"
was
not
defined
in
either
of
the
publications
and
the
second
publication
merely
cited
the
first
as
the
source
of
their
information,
as
did
other
studies
found
in
the
literature.
Thus,
EFED's
fairly
extensive
literature
search
resulted
in
only
one
primary
reference
in
which
it
was
stated
that
PCP
is
a
soil
9
metabolite
of
PCNB.
Attempts
to
contact
the
study
authors
or
their
successors
at
the
(
former)
USDA
Pesticide
Degradation
Laboratory
were
unsuccessful.

In
the
first
publication
(
i.
e.,
Murthy
&
Kaufman),
the
study
authors
were
unable
to
quantify
the
amount
of
PCP
formed,
as
they
discarded
the
aqueous
portion
(
which
accounted
for
8­
16%
of
the
56­
58%
of
the
applied
that
was
extracted
from
the
soil
samples,
for
a
maximum
possible
level
of
9.28%
of
the
applied)
of
their
extract
following
an
organic
extraction,
and
were
therefore
unable
to
analyze
the
aqueous
phase
for
PCP.
In
subsequent
investigations,
the
study
authors
were
able
to
determine
(
through
GLC
and
TLC)
that
PCP
was
the
compound
present
in
the
aqueous
phase
of
the
soil
extract,
but
did
not
attempt
to
quantify
the
residues.

In
a
study
done
in
Japan,
it
appears
that
PCP
was
not
detected
in
a
volcanic
ash
soil
which
had
been
extensively
treated
in
the
past
with
PCNB
and
in
which
the
parent
compound
was
detected
in
the
soil
at
10.10
ppm
(
Ohsawa
et
al.,
1984).
However,
the
compound
pentachloroanisole
(
PCAN),
which
is
a
methylated
derivative
of
and
can
interconvert
with
PCP
under
certain
conditions,
was
detected
at
0.009
ppm.
(
Further
interpretation
of
this
study
was
hindered
by
the
fact
that
much
of
the
text
was
in
Japanese
and
a
translation
was
not
available.)
It
has
been
suggested
in
the
literature
that
PCAN
is
the
product
of
the
microbial
degradation
of
PCP
following
that
compound's
formation
from
PCNB
by
soil
microbes
(
Murthy
and
Kaufman,
1978;
Murthy
et
al.,
1979).
In
a
study
of
PCNB
degradation
by
fungi,
PCAN
was
detected
(
Mora­
Torres
et
al.,
1996).
In
a
study
on
PCNB
degradation
by
soil
microbes
native
to
France,
neither
PCP
nor
PCAN
were
observed;
degradates
included
only
PCA
and
PCTA
(
Mora­
Torres
et
al.,
2000).

In
a
study
of
the
metabolism
of
PCNB
in
anaerobic
sediment
in
Japan,
PCP
was
not
identified
as
a
degradate;
degradates
included
pentachloroaniline,
2,3,4,5­
tetrachloroaniline,
3,4,5­
trichloroaniline,
3,5­
dichloroaniline
and
3­
chloroaniline
(
with
2­
CA
and
4­
CA
identified
as
intermediates;
Susarla
et
al.,
1996).
Tetrachloroaniline
has
also
been
identified
as
a
metabolite
of
PCNB
in
other
studies
(
Mora­
Torres
et
al.,
1996).

These
results
indicate
that
there
are
conditions
under
which
PCP
can
form
in
the
environment,
but
does
not
form
under
all
conditions.
At
this
point
in
time,
we
do
not
have
sufficient
information
to
determine
what
conditions
favor
PCP
formation
and
which
do
not.
Nor
is
there
sufficient
information
to
quantify
the
amount
and
rate
of
formation
of
PCP
from
PCNB
when
PCP
is
produced.
Consequently,
EFED
is
unable
to
estimate
how
much
PCP
might
occur
in
drinking
water
from
PCNB
use.
EFED
has
indicated
to
SRRD
that
additional
data
on
the
microbial
metabolism
of
PCNB
in
both
aerobic
and
anaerobic
soil/
water
systems
are
necessary
for
a
more
complete
evaluation
of
the
risks
associated
with
PCNB,
particularly
with
regard
to
PCP.

Literature
Cited
California
EPA;
Sampling
for
pesticide
residues
in
California
well
water.
1995
Update
of
The
Well
Inventory
Database
in
California.
CA
Environmental
Protection
Agency,
Dept.
of
Pesticide
Regulation,
10th
Annual
Report.
(
December
1995)
10
Cohen,
S.,
A.
Svrjcek,
T.
Durborrow,
N.
Lajan
Barnes.
Water
quality
impacts
by
golf
courses.
J.
Environ.
Qual.
28:
798­
809.

Mora­
Torres,
R.,
C.
Grosset
and
J.
Alary.
Chromatographia
51:
526­
530
(
2000).

Mora­
Torres,
R.,
C.
Grosset,
R.
Steiman,
and
J.
Alary.
Liquid
chromatography
study
of
degradation
and
metabolism
of
pentachloronitrobenzene
by
four
soil
micromycetes.
Chemosphere
33:
683­
692
(
1996).

Motoyama,
T.,
K.
Kadokura,
S.
Tatsusawa,
T.
Arie,
and
I.
Yamaguchi.
Application
of
plant
microbe
systems
to
bioremediation.
RIKEN
Re.
42:
35­
38
(
2001).

Murthy,
N.
B.
K.
and
D.
D.
Kaufman.
Degradation
of
pentachloronitrobenzene
(
PCNB)
in
anaerobic
soils.
J.
Agric.
Food
Chem.
26:
1151­
1156.
(
1978).

Murthy,
N.
B.
K.,
D.
D.
Kaufman
and
G.
F.
Fries.
Degradation
of
pentachlorophenol
(
PCP)
in
aerobic
and
anaerobic
soil.
J.
Environ.
Sci.
Health
B14:
1­
14
(
1979).

Ohsawa,
K.,
T.
Miyamoto,
and
I.
Yamamoto.
Residue
analysis
of
pentachloronitrobenzene
and
its
related
compound
(
sic)
in
soils
by
mass
fragmentography.
J.
Pestic.
Sci.
9:
339­
345
(
1984).

Rostad,
C.
E.,
W.
E.
Pereira
and
T.
J.
Leiker.
1999.
Distribution
and
transport
of
selected
anthropogenic
lipophilic
organic
compounds
associated
with
Mississippi
River
suspended
sediment,
1989
 
1990.
Archives
of
Environ.
Contam.
and
Tox.
36:
248
 
255.

Susarla,
S.,
S.
Masunaga
and
Y.
Yonezawa.
Transformation
of
chloronitrobenzenes
in
anaerobic
sediment.
Chemosphere
32:
967­
977
(
1996).

USEPA.
Pesticides
in
groundwater
database.
A
compilation
of
monitoring
studies:
1971­
1991.
National
summary.
USEPA/
OPP/
OPPTS.
USEPA­
734­
12­
92­
001
(
1992).
11
ATTACHMENT
1:
FIRST
File
RUN
No.
1
FOR
pcnb
ON
turf
*
INPUT
VALUES
*
­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­
RATE
(#/
AC)
No.
APPS
&
SOIL
SOLUBIL
APPL
TYPE
%
CROPPED
INCORP
ONE(
MULT)
INTERVAL
Kd
(
PPB
)
(%
DRIFT)
AREA
(
IN)
­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­
32.670(
65.036)
2
21
15.5
440.0
GRANUL(
.0)
87.0
.0
FIELD
AND
RESERVOIR
HALFLIFE
VALUES
(
DAYS)
­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­
METABOLIC
DAYS
UNTIL
HYDROLYSIS
PHOTOLYSIS
METABOLIC
COMBINED
(
FIELD)
RAIN/
RUNOFF
(
RESERVOIR)
(
RES.­
EFF)
(
RESER.)
(
RESER.)
­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­
1555.00
2
N/
A
1.83­
226.92
******
211.49
UNTREATED
WATER
CONC
(
MICROGRAMS/
LITER
(
PPB))
Ver
1.0
AUG
1,
2001
­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­
PEAK
DAY
(
ACUTE)
ANNUAL
AVERAGE
(
CHRONIC)
CONCENTRATION
CONCENTRATION
­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­
440.000
440.000
12
ATTACHMENT
2:
SCI­
GROW
File
SCIGROW
VERSION
2.3
ENVIRONMENTAL
FATE
AND
EFFECTS
DIVISION
OFFICE
OF
PESTICIDE
PROGRAMS
U.
S.
ENVIRONMENTAL
PROTECTION
AGENCY
SCREENING
MODEL
FOR
AQUATIC
PESTICIDE
EXPOSURE
SciGrow
version
2.3
chemical:
pcnb
time
is
10/
20/
2003
13:
19:
59
­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­
Application
Number
of
Total
Use
Koc
Soil
Aerobic
rate
(
lb/
acre)
applications
(
lb/
acre/
yr)
(
ml/
g)
metabolism
(
days)
­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­
213.400
1.0
213.400
1.59E+
03
750.5
­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­
groundwater
screening
cond
(
ppb)
=
3.06E+
01
*************************************************************************
13
ATTACHMENT
3:
General
fate
and
physical­
chemical
property
source
data
for
PCNB
modeling.

PARAMETER
VALUE
Chemical
Name
pentachloronitrobenzene
Molecular
Weight
295.3
Solubility
(
25
oC)
0.44
mg/
L
(
440
ppb)

Vapor
Pressure
(
25
oC)
1.13
x
10­
4
mmHg
Hydrolysis
Half­
life
(
pH
5,
7,
9;
25
oC)
stable
(
MRID's
40865301,
40972601)

Aqueous
Photolysis
Half­
life
(
pH
7)
t
1/
2
=
2.5
days
(
MRID's
42606201,
42606202)
t
1/
2
=
26.8
hours
(
MRID
42336201)

Soil
Photolysis
Half­
life
stable
(
MRID's
41004801,
41713201)

Aerobic
Soil
Metabolism
Half­
life
t
1/
2
=
77,
189
days
(
parent
only);
t
1/
2
=
489,
1012
days
(
parent
plus
PCA)
1
t
1/
2
=
983,
1052
days
(
total
residues)
2
(
MRID's
42911902,
41384501,
41713202,
42112801)

Anaerobic
Soil
Metabolism
Half­
life
t
1/
2
=
9
days,
<
30
(
DT
50;
parent
only);
t
1/
2
=
210,
410
days
(
parent
plus
PCA,
PCP)
t
1/
2
=
268,
334
days
(
total
residues)
(
MRID's
41203602,
42094401,
41384301,
41686001,
41713202,
42112802)

Organic
Carbon
Partition
Coefficient
(
K
oc)
1588,
2912,
3870,
17508
(
MRID
41648201)

Soil
Partition
Coefficient
(
K
d,
mL/
g)
7.3,
15.5,
19.1,
210
(
MRID
41648201)

1For
the
purposes
of
the
drinking
water
assessment,
half­
lives
were
recalculated
to
account
for
the
parent
plus
the
degradates
PCA
and
PCP,
when
monitored
and
detected.
2For
the
purposes
of
the
ecological
assessment,
half­
lives
were
recalculated
to
account
for
total
residues,
inclusive
of
the
parent
plus
the
degradates
PCA,
PCTA,
PCB,
PCP,
PCTASO,
PCTASO
2,
and
the
manufacturing
contaminant
HCB.
