Background
Information:

The
Clean
Water
Act
(
CWA)
requires
EPA
to
periodically
review
and
publish
criteria
for
water
quality,
accurately
reflecting
the
latest
scientific
knowledge.
Water
quality
criteria
developed
under
section
304(
a)
are
based
solely
on
data
and
scientific
judgments.
They
do
not
consider
economic
impacts
or
the
technological
feasibility
of
meeting
the
criteria
in
ambient
water.
Section
304(
a)
criteria
provide
guidance
to
States
and
Tribes
in
adopting
water
quality
standards
and
provide
a
scientific
basis
for
them
to
develop
controls
of
discharges
or
releases
of
pollutants.

Throughout
the
years
EPA
has
developed
and
revised
criteria
for
protection
of
human
health
and
aquatic
life
for
various
pollutants.
EPA
published
aquatic
life
criteria
for
copper
in
1980,
1985
and
1995.
EPA
is
currently
in
the
process
of
revising
its
aquatic
life
criteria
for
copper
once
again.

EPA's
latest
revision
to
its
copper
criteria
is
based
on
the
results
of
a
recent
literature
review.
Newly
identified
studies
were
reviewed
and
their
suitability
for
use
in
deriving
aquatic
life
criteria
was
evaluated.
New
data
were
considered
in
developing
the
draft
criteria
and
studies
that
were
previously
evaluated
and
considered
acceptable
for
use
in
deriving
criteria
were
also
reevaluated
as
a
part
of
this
effort.

In
addition
to
updating
the
criteria
based
on
new
literature,
EPA
incorporated
the
biotic
ligand
model
(
BLM)
into
the
freshwater
criteria
calculation
procedure.
The
BLM
is
based
on
the
premise
that
toxicity
is
related
to
metal
bound
to
a
biological
site
(
or
`
biotic
ligand')
and
that
binding
is
related
to
total
dissolved
metal
concentrations
and
complexing
ligands
in
the
water.
The
complexing
ligands
compete
with
the
biotic
ligand
for
metals
and
other
cations
in
the
water.
Unlike
the
empirical
harness
relationships
the
BLM:
explicitly
accounts
for
individual
water
quality
variables;
is
not
linked
to
a
particular
correlation
among
these
variables;
and
can
address
variables
that
were
not
a
factor
in
the
hardness
relationship.

Technical
Charge:

The
peer
reviewers
are
charged
with
examining
the
available
data
concerning
the
adverse
effects
of
acute
and
chronic
exposures
to
copper
on
aquatic
organisms
and
commenting
on
the
following
technical
issues.
In
responding
to
the
various
technical
questions
the
reviewers
must
make
clear
the
supporting
rational
for
their
conclusions.
However,
peer
reviewers
should
not
necessarily
limit
their
review
to
only
these
questions.

1.
Comment
on
the
appropriateness
of
the
freshwater
and
saltwater
Criterion
Maximum
Concentrations
(
CMCs)
and
Criterion
Continuous
Concentrations
(
CCCs).

2.
Measurements
of
BLM
input
parameters
were
not
available,
for
all
parameters,
for
all
studies
used
to
derive
the
criteria.
In
some
cases
therefore,
input
parameters
were
estimated.
A
detailed
description
of
the
methods
used
to
estimate
these
missing
parameters
is
included
in
the
Appendix,
Estimation
of
Water
Chemistry
Parameters
for
Acute
Copper
Toxicity
Tests.
Are
any
of
the
estimation
procedures
for
the
parameters
inappropriate
or
could
other
methods
be
used
to
improve
the
estimations?
3.
The
freshwater
criteria
presented
in
this
document
were
developed
utilizing
the
biotic
ligand
model
(
BLM).
Are
the
BLM­
derived
copper
criteria
an
improvement
over
the
hardness­
dependent
copper
criteria?

4.
Is
the
description
of
the
methods
used
to
incorporate
the
BLM
into
the
criteria
calculation
procedures
clearly/
adequately
described?
Are
the
procedures
appropriate?
Is
the
establishment
of
the
chronic
criterion
through
the
BLM­
calculated
FAV
and
the
assigned
ACR
appropriate?

5.
Based
on
the
report
provided
by
Patrick
Gaffney,
regarding
the
DNA
analysis
of
Mytilus
species,
EPA
agreed
that
species
collected
and
tested
from
the
west
coast
were
likely
not
M.
edulis
and
thus
calculated
SMAVs
for
both
M.
edulis
and
M.
spp.
The
calculated
saltwater
final
acute
value
(
FAV)
was
higher
than
the
SMAV
for
the
M.
spp.
and
so,
pursuant
to
the
1985
Guideline
procedures,
the
FAV
was
lowered
to
protect
the
commercially
important
M.
spp.
To
calculate
the
saltwater
final
chronic
value
(
FCV)
this
FAV
(
or
M.
spp.
SMAV)
was
divided
by
a
final
acute­
chronic
ratio
(
FACR)
derived
from
both
freshwater
and
saltwater
species,
implying
that
a
`
5th
percentile'
ACR
was
applicable
for
use
in
conjunction
with
the
M.
spp.­
FAV.
Comment
on
the
appropriateness
of
any/
all
facet(
s)
of
this
calculation
procedure.
