E­
1
Appendix
E
Saltwater
Conversion
Factors
for
Dissolved
Values
September
26,
2002
U.
S.
Environmental
Protection
Agency
Office
of
Water
Office
of
Science
and
Technology
Washington,
D.
C.
E­
2
ACKNOWLEDGMENTS
Larry
Brooke
and
Tyler
Linton
(
primary
authors)
Great
Lakes
Environmental
Center
1295
King
Avenue
Columbus,
OH
43212
Jennifer
Mitchell
and
Cindy
Roberts
(
authors
and
document
coordinators)
U.
S.
Environmental
Protection
Agency
Washington,
DC
E­
3
Saltwater
Conversion
Factors
for
Converting
Nominal
or
Total
Copper
Concentrations
to
Dissolved
Copper
Concentrations
The
U.
S.
EPA
changed
its
policy
in
1993
of
basing
water
quality
criteria
for
metals
from
a
total
metal
criteria
to
a
dissolved
metal
criteria.
The
policy
states
"
the
use
of
dissolved
metal
to
set
and
measure
compliance
with
water
quality
standards
is
the
recommended
approach,
because
dissolved
metal
more
closely
approximates
the
bioavailable
fraction
of
metal
in
the
water
column
than
does
total
recoverable
metal"
(
Prothro
1993).
All
of
the
criteria
for
metals
to
this
date
were
based
upon
total
metal
and
very
few
data
were
available
with
dissolved
concentrations
of
the
metals.
A
problem
was
created
by
the
new
policy
of
how
to
derive
dissolved
metal
concentrations
for
studies
in
which
this
form
of
the
metal
was
not
measured.
The
U.
S.
EPA
attempted
to
develop
correction
factors
for
each
metal
for
which
criteria
exist
for
both
fresh­
and
saltwater
(
Lussier
et
al.
1995;
Stephan
1995).
In
the
case
of
saltwater,
a
correction
for
copper
was
not
derived.

Several
saltwater
studies
are
available
that
report
nominal,
total,
and
dissolved
concentrations
of
copper
in
laboratory
water
(
Table
1)
from
site­
specific
water
effect
ratio
(
WER)
studies.
These
studies
show
relatively
consistent
ratios
for
the
nominal­
to­
dissolved
concentrations
and
for
the
total­
to­
dissolved
concentrations.
Calculation
of
a
mean
ratio
(
conversion
factor)
to
convert
nominal
and
total
copper
concentrations
to
dissolved
copper
permits
the
use
of
the
results
for
critical
studies
without
dissolved
copper
measurements.

Three
studies,
each
with
multiple
tests
per
study,
were
useful
for
deriving
the
conversion
factors.
One
study
was
conducted
for
the
lower
Hudson
River
in
the
New
York/
New
Jersey
Harbor
(
SAIC
1993).
The
tests
were
conducted
with
harbor
site
water
and
with
EPA
Environmental
Research
Laboratory
­
Narragansett
water
from
Narragansett
Bay,
Massachusetts.
Only
the
tests
with
laboratory
water
were
used
for
this
exercise.
Three
series
of
48­
hour
static
tests
were
conducted
with
various
animals.
Salinity
ranged
from
28
to
32
ppt
during
all
the
tests.
Series
1
tests
were
not
used
to
calculate
ratios
for
dissolved­
to­
total
or
dissolved­
to­
nominal
copper
concentrations,
because
in
many
instances,
concentrations
of
measured
copper
did
not
increase
as
nominal
concentrations
increased.
Of
the
series
2
tests,
only
the
coot
clam
(
Mulinia
lateralis)
tests
were
successful
and
used
to
calculate
ratios.
Three
replicate
tests
without
ultraviolet
(
UV)
light
present
and
one
test
with
UV
light
present
were
reported
with
total
and
dissolved
copper
measurements
made
at
0
hr
and
48
hr
(
end)
of
the
tests.
Dissolved­
to­
total
and
dissolved­
to­
nominal
ratios
were
calculated
for
the
four
tests
each
with
two
time
intervals.
The
mean
ratio
for
the
dissolved­
tototal
measurements
is
0.943
and
the
mean
ratio
for
the
dissolved­
to­
nominal
is
0.917.
A
third
series
of
static
tests
was
conducted
by
SAIC
and
the
mussel
(
Mytilus
sp.)
test
was
the
only
successful
test.
Again
the
tests
were
conducted
as
three
replicate
tests
without
UV
light
and
a
fourth
with
UV
light.
The
mean
test
ratio
for
dissolved­
to­
total
copper
was
0.863
and
the
dissolved­
to­
nominal
mean
test
ratio
was
0.906.

The
summer
flounder
(
Paralichthys
dentatus)
was
exposed
to
copper
in
laboratory
water
for
96
hours
in
a
static
test
(
CH2MHill
1999a).
The
water
was
collected
from
Narragansett
Bay
and
diluted
with
laboratory
reverse
osmosis
water
to
dilute
the
solution
to
22
ppt
salinity.
Three
tests
were
run
with
copper
concentrations
measured
at
the
start
of
the
tests
as
total
recoverable
and
dissolved
copper.
Five
exposure
concentrations
were
used
to
conduct
the
tests.
Only
the
two
lowest
concentrations
were
used
to
derive
ratios
for
dissolved­
to­
total
and
dissolved­
to­
nominal
copper
mean
ratios.
These
concentrations
were
at
the
approximate
500

g/
L
or
lower
concentrations,
and
are
in
the
range
of
most
copper
concentrations
routinely
tested
in
the
laboratory.
The
mean
dissolved­
to­
total
and
dissolved­
to­
nominal
ratios
were
0.947
and
0.836,
respectively.

Three
48­
hour
static
tests
were
conducted
with
the
blue
mussel
(
Mytilus
edulis)
in
water
from
the
same
source
and
treated
in
the
same
manner
as
the
summer
flounder
tests
(
CH2MHill
1999b).
Salinity
was
E­
4
diluted
to
20
ppt.
Exposures
were
made
at
eight
concentrations
of
copper
and
total
and
dissolved
copper
concentrations
were
measured
only
at
the
start
of
the
tests.
Mean
ratios
for
the
dissolved­
to­
total
and
dissolved­
to­
nominal
copper
were
calculated
by
combining
the
ratios
calculated
for
each
of
the
test
concentrations.
The
mean
dissolved­
to­
total
and
dissolved­
to­
nominal
ratios
were
0.979
and
0.879,
respectively.

A
study
was
conducted
by
the
City
of
San
Jose,
CA
to
develop
a
WER
for
San
Francisco
Bay
in
which
copper
was
used
as
a
toxicant
and
the
concentrations
used
in
the
laboratory
exposures
were
measured
as
total
and
dissolved
copper
(
Environ.
Serv.
Dept.,
City
of
San
Jose
1998).
Mussels
and
the
purple
sea
urchin
(
Strongylocentrotus
purpuratus)
were
used
as
the
test
organisms.
Tests
were
conducted
in
filtered
natural
sea
water
from
San
Francisco
Bay
that
was
diluted
to
a
salinity
of
28
ppt.
The
mussel
test
was
of
48­
hour
duration
and
the
purple
sea
urchin
test
was
of
96­
hour
duration.
Five
concentrations
of
copper
were
used
in
the
toxicity
tests
with
the
concentrations
measured
at
the
start
of
each
test.
(
During
each
test,
a
single
concentration
of
copper
was
measured
at
the
termination
of
the
test
and
this
value
was
not
used
in
the
calculations.)
Twenty­
two
tests
were
conducted
during
a
13­
month
period
with
the
mussel
and
two
tests
were
conducted
with
the
purple
sea
urchin.
The
mean
dissolved­
to­
total
and
dissolved­
tonominal
ratios
for
the
mussel
tests
were
0.836
and
0.785,
respectively.
The
mean
dissolved­
to­
total
and
dissolved­
to­
nominal
ratios
for
the
purple
sea
urchin
were
0.883
and
0.702,
respectively.

For
some
of
the
tests,
control
concentrations
had
measured
concentrations
of
total
and
dissolved
copper.
These
values
were
not
used
to
calculate
ratios
for
dissolved­
to­
total
and
dissolved­
to­
nominal
copper
concentrations.
All
mean
ratios
were
calculated
as
the
arithmetic
mean
and
not
as
a
geometric
mean
of
the
available
ratios.
When
the
data
are
normally
distributed,
the
arithmetic
mean
is
the
appropriate
measure
of
central
tendency
(
Parkhurst
1998)
and
is
a
better
estimator
than
the
geometric
mean.
All
concentrations
of
copper
used
to
calculate
ratios
should
be
time­
weighted
averages
(
Stephan
1995).
In
all
instances
of
data
used
to
calculate
ratios,
the
concentrations
were
identical
to
time­
weighted
values
because
either
only
one
value
was
available
or
if
two
were
available
they
were
of
equal
weight.

Based
on
the
information
presented
above
the
overall
ratio
for
correcting
total
copper
concentrations
to
dissolved
copper
concentrations
is
0.909
based
upon
the
results
of
six
sets
of
studies.
This
is
comparable
to
its
equivalent
factor
in
freshwater,
which
is
0.960
±
0.037
(
Stephan
1995).
When
it
is
necessary
to
convert
nominal
copper
concentrations
to
dissolved
copper
concentrations
the
conversion
factor
is
0.838
based
upon
the
same
studies.
The
means
of
both
conversion
factors
have
standard
deviations
of
less
than
ten
percent
of
the
means
(
Table
1).
E­
5
Table
E­
1.
Summary
of
Saltwater
Copper
Ratios
Species
Mean
Dissolved­
to­
Total
Ratio
Mean
Dissolved­
to­
Nominal
Ratio
Reference
Coot
clam,
Mulinia
lateralis
0.943
0.917
SAIC
1993
Summer
flounder,
Paralichthys
dentatus
0.947
0.836
CH2MHill
1999a
Blue
mussel,
Mytilus
sp
0.863
0.906
SAIC
1993
Blue
mussel,
Mytilus
edulis
0.979
0.879
CH2MHill
1999b
Blue
mussel,
Mytilus
sp
0.836
0.785
Environ.
Serv.
Dept.,
City
of
San
Jose
1998
Purple
sea
urchin,
Strongylocentrotus
purpuratus
0.883
0.702
Environ.
Serv.
Dept.,
City
of
San
Jose
1998
Arithmetic
Mean
0.909
0.838
Standard
Deviation
±
0.056
±
0.082
E­
6
References
CH2MHill.
1999a.
Bioassay
report:
Acute
toxicity
of
copper
to
summer
flounder
(
Paralichthys
dentatus).
Final
report
prepared
for
U.
S.
Navy.
November
1999.
CH2MHill,
Norfolk,
Virginia.
26
p.

CH2MHill.
1999b.
Bioassay
report:
Acute
toxicity
of
copper
to
blue
mussel
(
Mytilus
edulis).
Final
report
prepared
for
U.
S.
Navy.
November
1999.
CH2MHill,
Norfolk,
Virginia.
41
p.

Environmental
Services
Department,
City
of
San
Jose.
1998.
Development
of
a
site­
specific
water
quality
criterion
for
copper
in
south
San
Francisco
Bay.
Environmental
Services
Department,
City
of
San
Jose,
San
Jose/
Santa
Clara
Water
Pollution
Control
Plant,
4245
Zanker
Road,
San
Jose,
CA.
171
pp.
May.

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S.
M.,
W.
S.
Boothman,
S.
Poucher,
D.
Champlin
and
A.
Helmsteter.
1995.
Derivation
of
conversion
factors
for
dissolved
saltwater
aquatic
life
criteria
for
metals.
Draft
report
to
the
U.
S.
EPA,
Office
of
Water.
U.
S.
EPA,
Narragansett,
RI.
March
31,
1995.

Parkhurst,
D.
F.
1998.
Arithmetic
versus
geometric
means
for
environmental
concentration
data.
Environ.
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32:
92A­
95A.

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M.
1993.
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concerning
"
Office
of
Water
Policy
and
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Guidance
on
Interpretation
and
Implementation
of
Aquatic
Life
Metals
Criteria."
October
1.

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1993.
Toxicity
testing
to
support
the
New
York/
New
Jersey
Harbor
site­
specific
copper
criteria
study.
Final
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to
U.
S.
EPA,
Office
of
Wastewater
Enforcement
and
Compliance
(
Contract
No.
68­
C8­
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4­
94).
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International
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Narragansett,
RI.

Stephan,
C.
E.
1995.
Derivation
of
conversation
factors
for
the
calculation
of
dissolved
freshwater
aquatic
life
criteria
for
metals.
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March
11,
1995.
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MN.
