Document ID: EPA-HQ-OW-2003-0002-0100
Agency: epa
Document Type: Proposed Rule
Title: Guidelines Establishing Test Procedures for the Analysis of Pollutants; Measurement of Mercury in Water (EPA Method 1631, Revision B); Final Rule.
Posted Date: 2003-03-12T05:00Z

30417
Federal
Register
/
Vol.
64,
No.
109
/
Tuesday,
June
8,
1999
/
Rules
and
Regulations
TABLE
1.
 
PM
POST­
REBUILD
LEVELS
(
G/
BHP­
HR)
FOR
CALCULATING
TLFS
FOR
CALENDAR
YEAR
2000
AND
THEREAFTERK
1
 
Continued
Engine
model
Model
year
Pre­
rebuild
level
Post­
Rebuild
level
2
Engine
code
Engine
family
DDC
6V71N
........
1973
 
87
...................
0.50
..........................
0.38
..........................
All
.............................
All.
DDC
6V71N
........
1988
 
89
...................
0.50
..........................
0.38
..........................
All
.............................
All.
DDC
6V71T
.........
1985
 
86
...................
0.50
..........................
0.38
..........................
All
.............................
All.
DDC
8V71N
........
1973
 
84
...................
0.50
..........................
0.38
..........................
All
.............................
All.
DDC
6L71TA
.......
1990
.........................
0.59
..........................
0.59
..........................
All
.............................
All.
DDC
6L71TA
.......
1988
 
89
...................
0.31
..........................
0.23
..........................
All
.............................
All.
DDC
6V71TA
DDEC
..
1990
 
91
...................
0.30
..........................
0.23
..........................
All
.............................
All.
DDC
8V92TA
......
1979
 
87
...................
0.50
..........................
0.38
..........................
All
.............................
8V92TA.
1988
.........................
0.39
..........................
0.29
..........................
All
.............................
8V92TA.
DDC
8V92TA
DDEC
..
1988
.........................
0.41
..........................
0.31
..........................
All
.............................
8V92TA
 
DDEC
II.
DDC
8V92TA
......
1989
.........................
0.47
..........................
0.35
..........................
9E70
........................
KDD0736FW89.
DDC
8V92TA
......
1989
.........................
0.39
..........................
0.29
..........................
9A90
........................
KDD0736FW89.
DDC
8V92TA
......
1989
.........................
0.34
..........................
0.26
..........................
9G85
........................
KDD0736FW89.
DDC
8V92TA
DDEC
..
1989
.........................
0.41
..........................
0.31
..........................
1A
............................
KDD0736FZH4.
DDC
8V92TA
......
1990
.........................
0.47
..........................
0.35
..........................
9E70
........................
LDD0736FAH9.
DDC
8V92TA
DDEC
..
1990
.........................
0.49
..........................
0.37
..........................
1A
............................
LDD0736FZH3.
DDC
8V92TA
DDEC
..
1991
.........................
0.25
..........................
0.19
..........................
1A
or
5A
..................
MDD0736FZH2.
DDC
8V92TA
DDEC
..
1992
 
93
...................
0.21
..........................
0.16
..........................
1D
............................
NDD0736FZH1
&
PDD0736FZH
X.
DDC
8V92TA
DDEC
..
1992
 
93
...................
0.29
..........................
0.22
..........................
6A
............................
NDD0736FZH
1
&
PDD0736FZH
X.
DDC
8V92TA
DDEC
..
1992
 
93
...................
0.20
..........................
0.15
..........................
5A
............................
NDD0736FZH
1
&
PDD0736FZHX.
DDC
8V92TA
DDEC
..
1992
 
93
...................
0.25
..........................
0.19
..........................
1A
............................
NDD0736FZH
1
&
PDD0736FZHX.
CUMMINS
L
 
10
.........
1985
 
1987
...............
0.65
..........................
0.34
..........................
All
.............................
All.
1988
 
1989
...............
0.55
..........................
0.34
..........................
All
.............................
All.
1990
 
1992
...............
0.46
..........................
0.34
..........................
All
.............................
All.
L
 
10EC
............
1992
.........................
0.25
..........................
0.19
..........................
All
.............................
All.
Cummins
L
 
10
EC
w/
trap.
1993
.........................
0.05
..........................
0.05
..........................
All
.............................
All.

Alternatively­
Fueled
Engines.
pre
 
1994
.................
0.10
..........................
0.10
..........................
All
.............................
All.

Other
Engines
............
pre
 
1988
.................
0.50
..........................
0.50
..........................
All
.............................
All.
1988
 
1993
...............
Cert'n
Level
3
...........
Cert'n
Level
3
...........
All
.............................
All.

1
In
accordance
with
40
CFR
85.1403(
c)(
1)(
iv).
2
The
instructions
for
the
spreadsheet
list
these
levels
as
post­
rebuild­
3
levels.
The
instructions
are
available
upon
request
from
the
contact
listed
above.
3
Use
the
certification
level
determined
under
EPA's
new
engine
certification
program.

An
urban
bus
operator
choosing
to
comply
with
Option
2
must
be
able
to
demonstrate
at
all
times
in
a
specified
year
that
its
fleet
level
attained
(
FLA)
is
equal
to
or
less
than
its
TLF
for
that
year.
Using
the
formulas
in
40
CFR
85.1403(
c)(
1)
and
the
PM
emissions
levels
(
including
the
above
post­
rebuild
levels)
in
accordance
with
section
85.1403(
a)(
1)(
iv),
operators
choosing
Option
2
must
calculate
their
TLF
for
calendar
year
2000
and
thereafter.
The
FLA
is
calculated
using
the
formula
of
40
CFR
85.1403(
c)(
2)
and
the
certification
level
of
the
specific
equipment
installed
on
each
bus.
In
order
to
ensure
it
is
in
compliance
with
its
TLF
at
the
start
of
calendar
year
2000
and
thereafter,
transit
operators
choosing
to
comply
with
Option
2
are
expected
to
begin
taking
appropriate
actions
(
such
as
installing
certified
equipment
and/
or
retiring
buses)
no
later
than
calendar
year
1999.
Dated:
May
21,
1999.
Robert
Perciasepe,
Assistant
Administrator
for
Air
and
Radiation.
[
FR
Doc.
99
 
13802
Filed
6
 
7
 
99;
8:
45
am]

BILLING
CODE
6560
 
50
 
P
ENVIRONMENTAL
PROTECTION
AGENCY
40
CFR
Part
136
[
FRL
 
6354
 
3]

RIN
2040
 
AD07
Guidelines
Establishing
Test
Procedures
for
the
Analysis
of
Pollutants;
Measurement
of
Mercury
in
Water
(
EPA
Method
1631,
Revision
B);
Final
Rule
AGENCY:
Environmental
Protection
Agency
(
EPA).
ACTION:
Final
rule.
SUMMARY:
This
final
regulation
amends
the
``
Guidelines
Establishing
Test
Procedures
for
the
Analysis
of
Pollutants''
under
section
304(
h)
of
the
Clean
Water
Act
by
adding
EPA
Method
1631,
Revision
B:
Mercury
in
Water
by
Oxidation,
Purge
and
Trap,
and
Cold
Vapor
Atomic
Fluorescence
Spectrometry.
EPA
Method
1631
measures
mercury
at
the
low
levels
associated
with
ambient
water
quality
criteria
(
WQC).
EPA
has
promulgated
WQC
for
mercury
at
12
parts­
per­
trillion
(
ppt)
in
the
National
Toxics
Rule,
and
published
a
criterion
for
mercury
at
1.3
ppt
in
the
Water
Quality
Guidance
for
the
Great
Lakes
System.
The
version
of
Method
1631
promulgated
today
includes
changes
to
the
method
based
on
public
comments
at
proposal
(
63
FR
28867,
May
26,
1998).
These
changes
increase
measurement
reliability
at
WQC
levels.
EPA
recommends
the
use
of
clean
sampling
and
laboratory
techniques
in
conjunction
with
EPA
Method
1631
to
preclude
contamination
30418
Federal
Register
/
Vol.
64,
No.
109
/
Tuesday,
June
8,
1999
/
Rules
and
Regulations
at
the
low
ppt
levels
necessary
for
mercury
determinations.
EPA
has
published
guidance
documents
on
sampling
and
clean
rooms
for
trace
metals,
including
mercury.

EFFECTIVE
DATE:
This
regulation
is
effective
July
8,
1999.
For
judicial
review
purposes,
this
final
rule
is
promulgated
as
of
1:
00
p.
m.
Eastern
Standard
Time
on
June
22,
1999
in
accordance
with
40
CFR
23.7.
The
incorporation
by
reference
of
EPA
Method
1631
is
approved
by
the
Director
of
the
Federal
Register
July
8,
1999.
ADDRESSES:
Copies
of
the
public
comments
received,
EPA
responses,
and
all
other
supporting
documents
(
including
references
included
in
this
notice)
are
available
for
review
at
the
U.
S.
Environmental
Protection
Agency,
Water
Docket,
401
M
Street
SW,
Washington,
DC
20460.
For
access
to
docket
materials,
call
202/
260
 
3027
on
Monday
through
Friday,
excluding
Federal
holidays,
between
9
a.
m.
and
3:
30
p.
m.
Eastern
Standard
Time
for
an
appointment.
Copies
of
EPA
Method
1631
are
available
from
the
National
Technical
Information
Service
(
NTIS),
5285
Port
Royal
Road,
Springfield,
VA
22161,
(
703)
605
 
6000
or
(
800)
553
 
6847.
The
NTIS
publication
number
is
PB99
 
131989.
An
electronic
version
of
EPA
Method
1631
also
is
available
via
the
Internet
at
http://
www.
epa.
gov/
OST/
Methods.
FOR
FURTHER
INFORMATION
CONTACT:
For
information
regarding
EPA
Method
1631
contact
Maria
Gomez­
Taylor,
Ph.
D.,
Engineering
and
Analysis
Division
(
4303),
USEPA
Office
of
Science
and
Technology,
401
M
Street,
SW,
Washington,
DC
20460;
or
call
202/
260
 
1639.
SUPPLEMENTARY
INFORMATION:

Potentially
Regulated
Entities
EPA
Regions,
as
well
as
States,
Territories
and
Tribes
authorized
to
implement
the
National
Pollutant
Discharge
Elimination
System
(
NPDES)
program,
issue
permits
that
comply
with
the
technology­
based
and
water
qualitybased
requirements
of
the
Clean
Water
Act.
In
doing
so,
the
NPDES
permitting
authority,
including
authorized
States,
Territories,
and
Tribes,
make
a
number
of
discretionary
choices
associated
with
permit
writing,
including
the
selection
of
pollutants
to
be
measured
and,
in
many
cases,
limited
in
permits.
If
EPA
has
``
approved''
standardized
testing
procedures
(
i.
e.,
promulgated
through
rulemaking)
for
a
given
pollutant,
the
NPDES
permit
must
include
one
of
the
approved
testing
procedures
or
an
approved
alternate
test
procedure.
Regulatory
entities
may,
at
their
discretion,
require
use
of
this
method
in
their
permits.
Therefore,
entities
with
NPDES
permits
could
be
affected
by
the
standardization
of
testing
procedures
in
this
rulemaking,
because
NPDES
permits
may
incorporate
the
testing
procedures
in
today's
rulemaking.
In
addition,
when
a
State,
Territory,
or
authorized
Tribe
provides
certification
of
federal
licenses
under
Clean
Water
Act
section
401,
States,
Territories
and
Tribes
are
directed
to
use
the
standardized
testing
procedures.
Categories
and
entities
that
may
ultimately
be
affected
include:

Category
Examples
of
potentially
regulated
entities
Regional,
State
and
Territorial
Governments
and
Indian
Tribes
.............
States,
Territories,
and
Tribes
authorized
to
administer
the
NPDES
permitting
program;
States,
Territories,
and
Tribes
providing
certification
under
Clean
Water
Act
section
401;
Governmental
NPDES
permittees
Industry
.....................................................................................................
Industrial
NPDES
permittees.
Municipalities
............................................................................................
Publicly­
owned
treatment
works
with
NPDES
permits.

This
table
is
not
intended
to
be
exhaustive,
but
rather
provides
a
guide
for
readers
regarding
entities
likely
to
be
affected
by
this
action.
This
table
lists
the
types
of
entities
that
EPA
is
now
aware
could
potentially
be
affected
by
this
action.
Other
types
of
entities
not
listed
in
the
table
could
also
be
affected.
If
you
have
questions
regarding
the
applicability
of
this
action
to
a
particular
entity,
consult
the
person
listed
in
the
preceding
FOR
FURTHER
INFORMATION
CONTACT
section.

Outline
of
Preamble
I.
Authority
II.
Background
III.
Summary
of
Final
Rule
A.
Introduction
B.
Summary
of
EPA
Method
1631
C.
Sample
Contamination
D.
Quality
Control
E.
Performance­
Based
Measurement
System
IV.
Changes
to
EPA
Method
1631
Since
Proposal
A.
Holding
Time
Change
B.
Performance
Criteria
Change
C.
Reporting
Requirements
Changes
1.
Reporting
of
data
that
failed
to
meet
QC
acceptance
criteria
2.
Reporting
of
blank
results
3.
Reporting
laboratory­
specific
MDLs
and
MLs
D.
Other
Changes
and
Improvements
1.
Changes
to
method
implementation
2.
Corrections
to
method
3.
Clarifying
statements
4.
Additions
to
health
and
safety
monitoring
and
waste
management
V.
Public
Participation
and
Response
to
Comments
1.
Support
for
EPA
Method
1631
2.
Practicality
and
cost
3.
EPA
Method
1631
represents
a
significant
regulatory
action
4.
Regulatory
implications
5.
Retention
of
approved
methods
and
approval
of
additional
methods
6.
Application
to
wastewater
matrices
7.
Detection
and
quantitation
8.
Clean
techniques
9.
Corrections
to
statements
in
proposal
10.
Quality
control
11.
Blanks
and
contamination
12.
Validation
study
13.
Technical
details
of
EPA
Method
1631
14.
Miscellaneous
VI.
Regulatory
Requirements
A.
Executive
Order
12866
B.
Unfunded
Mandates
Reform
Act
C.
Regulatory
Flexibility
Act
D.
Paperwork
Reduction
Act
E.
Submission
to
Congress
and
the
General
Accounting
Office
F.
National
Technology
Transfer
and
Advancement
Act
G.
Executive
Order
13045
H.
Executive
Order
12875
I.
Executive
Order
13084
I.
Authority
Today's
regulation
is
being
promulgated
pursuant
to
the
authority
of
sections
301,
304(
h),
and
501(
a)
of
the
Clean
Water
Act
(
CWA),
33
U.
S.
C.
1314(
h),
1361(
a)
(
the
``
Act'').
Section
301
of
the
Act
prohibits
the
discharge
of
any
pollutant
into
navigable
waters
unless
the
discharge
complies
with
a
National
Pollutant
Discharge
Elimination
System
(
NPDES)
permit
issued
under
section
402
of
the
Act.
Section
304(
h)
of
the
Act
requires
the
Administrator
of
the
EPA
to
``
promulgate
guidelines
establishing
test
procedures
for
the
analysis
of
pollutants
that
shall
include
the
factors
which
must
be
provided
in
any
certification
pursuant
to
section
401
of
this
Act
or
permit
applications
pursuant
to
section
402
of
this
Act.''
Section
501(
a)
of
the
Act
authorizes
the
Administrator
to
30419
Federal
Register
/
Vol.
64,
No.
109
/
Tuesday,
June
8,
1999
/
Rules
and
Regulations
``
prescribe
such
regulations
as
are
necessary
to
carry
out
his
function
under
this
Act.''
EPA
publishes
CWA
analytical
method
regulations
at
40
CFR
part
136.
The
Administrator
also
has
made
these
test
procedures
applicable
to
monitoring
and
reporting
of
NPDES
permits
(
40
CFR
part
122,
§
§
122.21,
122.41,
122.44,
and
123.25),
and
implementation
of
the
pretreatment
standards
issued
under
section
307
of
the
Act
(
40
CFR
part
403,
§
§
403.10
and
402.12).

II.
Background
The
details
of
EPA
Method
1631
and
its
use
in
mercury
determinations
were
given
at
proposal
on
May
26,
1998
(
63
FR
28867).
On
March
5,
1999,
EPA
published
a
notice
of
data
availability
(
NODA)
with
results
from
additional
studies
of
municipal
and
industrial
effluents
using
EPA
Method
1631
(
64
FR
10596).
EPA
conducted
the
additional
studies
in
order
to
better
respond
to
comments
received
on
the
May
26,
1998
proposal.

III.
Summary
of
Final
Rule
A.
Introduction
Today's
action
makes
available
at
40
CFR
part
136
an
additional
test
procedure
for
measurement
of
mercury
in
aqueous
samples.
This
rulemaking
does
not
repeal
any
of
the
currently
approved
methods
that
measure
mercury.
For
an
NPDES
permit,
the
permitting
authority
should
decide
the
appropriate
method
based
on
the
circumstances
of
the
particular
water
sample
measured.
Use
of
EPA
Method
1631
may
be
specified
by
the
permitting
authority
when
a
permit
is
modified
or
reissued.
EPA
does
not
intend
for
Method
1631
to
be
a
de
facto
replacement
for
Method
245.1
or
any
of
the
other
existing
EPAapproved
methods
for
measurement
of
mercury.
EPA
intends
that
permit
writers
specify
the
use
of
Method
1631
when
measurement
at
very
low
levels
is
required,
for
example,
to
determine
compliance
with
water
quality­
based
effluent
limitations
duly
established
at
very
low
levels.

B.
Summary
of
EPA
Method
1631
EPA
Method
1631
has
four
procedural
components:
sample
pretreatment;
purge
and
trap;
desorption;
and
detection
by
atomic
fluorescence.
In
the
sample
pretreatment
step,
bromine
monochloride
(
BrCl)
is
added
to
the
sample
to
oxidize
all
forms
of
mercury
to
Hg(
II).
After
oxidation,
the
sample
is
sequentially
prereduced
with
NH2OH
·
HCl
to
destroy
free
halogens,
then
reduced
with
SnCl2
to
convert
Hg(
II)
to
volatile
Hg(
0).
The
Hg(
0)
is
purged
from
the
aqueous
solution
with
nitrogen
onto
a
gold­
coated
sand
trap.
The
trapped
mercury
is
thermally
desorbed
from
the
gold
trap
into
a
flowing
gas
stream
into
the
cell
of
a
cold­
vapor
atomic
fluorescence
spectrometer.
Quality
is
assured
through
calibration
and
testing
of
the
oxidation,
purging,
and
detection
systems.

C.
Sample
Contamination
Trace
levels
of
metals
are
ubiquitous
in
the
environment.
Therefore,
the
determination
of
trace
metals
at
the
levels
of
interest
for
water
quality
criteria
necessitates
the
use
of
clean
sample
handling
techniques
to
avoid
``
false
positive''
test
results
due
to
contamination
in
the
course
of
sample
collection,
handling,
or
analysis.
EPA
has
distributed
several
guidance
documents
that
are
designed
to
ensure
that
data
results
from
the
measurement
of
metals
in
aqueous
test
samples
accurately
reflect
actual
environmental
levels.
The
guidance
documents
include:
Method
1669:
Sampling
Ambient
Water
for
Trace
Metals
at
EPA
Water
Quality
Criteria
Levels
(
Sampling
Guidance),
EPA
 
821
 
R
 
96
 
001,
July
1996;
Guidance
on
Establishing
Trace
Metals
Clean
Rooms
in
Existing
Facilities,
EPA
 
821
 
B
 
96
 
001,
January
1996;
and
Guidance
on
Documentation
and
Evaluation
of
Trace
Metals
Data
Collected
for
Clean
Water
Act
Compliance
Monitoring,
EPA
 
821
 
B
 
96
 
004,
July
1996.
The
most
serious
problem
faced
by
laboratories
conducting
metals
analyses
at
these
very
low
levels
is
the
potential
for
sample
contamination
during
sample
collection
and
handling.
Sample
contamination
with
mercury
is
particularly
difficult
to
control
because
of
its
ubiquity
in
the
environment.
For
example,
commonly
used
polyethylene
sample
containers
are
unacceptable
for
sample
storage
because
atmospheric
mercury
may
diffuse
through
the
walls
of
the
container
causing
sample
contamination.
The
Sampling
Guidance
details
rigorous
sample
handling
and
quality
control
(
QC)
procedures
to
assure
that
reliable
data
are
obtained
for
mercury
at
the
levels
of
interest
for
water
quality
criteria.
EPA
recommends
that
the
procedures
described
in
the
Sampling
Guidance
be
followed
when
performing
low
level,
trace
metals
analyses
and
has
incorporated
certain
essential
elements
of
the
Guidance
in
the
method.

D.
Quality
Control
EPA
Method
1631
contains
all
of
the
standardized
QC
tests
proposed
in
EPA's
streamlining
initiative
(
62
FR
14976,
March
28,
1997)
and
used
in
test
procedures
in
40
CFR
part
136,
appendix
A.
Today's
rule
requires
an
initial
demonstration
of
laboratory
capability
which
consists
of:
(
1)
A
method
detection
limit
(
MDL)
study
to
demonstrate
that
the
laboratory
is
able
to
achieve
the
MDL
and
minimum
level
of
quantification
(
ML)
specified
in
EPA
Method
1631;
and
(
2)
an
initial
precision
and
recovery
(
IPR)
test,
consisting
of
analyses
of
four
reagent
water
samples
spiked
with
mercury,
to
demonstrate
the
laboratory's
ability
to
generate
acceptable
precision
and
recovery.
Today's
rule
also
requires
ongoing
QC
tests
for
each
analytical
batch,
(
i.
e.,
a
set
of
20
samples
or
less
pretreated
at
the
same
time):
·
Verification
of
calibration
of
the
purge
and
trap
and
atomic
fluorescence
systems
to
assure
that
instrument
response
has
not
deviated
significantly
from
the
instrument
response
obtained
during
calibration.
·
Analysis
of
a
matrix
spike
(
MS)
and
matrix
spike
duplicate
(
MSD)
to
demonstrate
method
accuracy
and
precision
and
to
monitor
matrix
interferences.
·
Analysis
of
reagent
and
bubbler
blanks
to
demonstrate
freedom
from
contamination.
·
Analysis
of
a
quality
control
sample
(
QCS)
and
ongoing
precision
and
recovery
(
OPR)
samples
to
demonstrate
that
the
method
remains
under
control.
EPA
Method
1631
contains
QC
acceptance
criteria
for
all
QC
tests.
Compliance
with
these
criteria
will
allow
a
data
user
to
evaluate
the
quality
of
the
results.
These
QC
acceptance
criteria
will
increase
the
reliability
of
results
and
provide
a
means
for
laboratories
and
data
users
to
monitor
analytical
performance,
thereby
providing
a
basis
for
sound,
defensible
data.

E.
Performance
Based
Measurement
System
On
March
28,
1997,
EPA
proposed
a
rule
(
62
FR
14976)
to
streamline
approval
procedures
and
use
of
analytic
methods
in
water
programs
through
implementation
of
a
performance­
based
approach
to
environmental
measurements.
On
October
7,
1997,
EPA
published
a
document
of
the
Agency's
intent
to
implement
a
Performance
Based
Measurement
System
(
PBMS)
in
all
media
programs
to
the
extent
feasible
(
62
FR
52098).
EPA's
water
program
offices
are
developing
plans
to
implement
PBMS.
EPA
anticipates
that
the
final
rule
to
implement
PBMS
in
water
programs
will
be
published
in
1999
based
on
the
March
28,
1997
30420
Federal
Register
/
Vol.
64,
No.
109
/
Tuesday,
June
8,
1999
/
Rules
and
Regulations
proposed
rule.
Consistent
with
Agency
PBMS
implementation
plans,
EPA
Method
1631
incorporates
QA
and
QC
acceptance
criteria
to
serve
as
a
basis
for
assessment
of
method
performance.
When
PBMS
is
in
place,
EPA
Method
1631
would
serve
as
a
reference
method
for
demonstrating
equivalency
when
modifications
are
made.
EPA
Method
1631
also
employs
a
performance­
based
approach
to
the
sample
preparation
and
trapping
systems.
Analysts
are
allowed
to
modify
the
sample
preparation
and
trapping
aspects
of
the
method
provided
all
the
specified
performance
criteria
are
demonstrated
and
documented.
The
method
also
allows
the
use
of
alternate
reagents
and
hardware
provided
that
the
analyst
demonstrates
equivalent
or
superior
performance
and
meets
all
QC
acceptance
criteria.
Demonstrating
equivalency
involves
two
sets
of
tests,
one
set
with
reference
standards
and
the
other
with
the
sample
matrix.
The
equivalency
procedures
include
performance
of
the
IPR
test
using
reference
standards
to
demonstrate
that
the
results
produced
with
the
modified
procedure
would
meet
or
exceed
the
QC
acceptance
criteria
in
EPA
Method
1631.
In
addition,
if
the
detection
limit
would
be
affected
by
a
modification,
performance
of
an
MDL
study
is
required
to
demonstrate
that
the
modified
procedure
could
achieve
an
MDL
less
than
or
equal
to
the
MDL
in
EPA
Method
1631
or,
for
those
instances
in
which
the
regulatory
compliance
limit
is
greater
than
the
ML
in
the
method,
one­
third
the
regulatory
compliance
limit.
For
a
discussion
of
these
levels,
see
EPA
Method
1631
or
the
March
28,
1997
proposed
rule
at
62
FR
14976.

IV.
Changes
to
EPA
Method
1631
Since
Proposal
The
Agency
has
revised
EPA
Method
1631,
Revision
A
based
on
comments
received
on
the
proposal
(
63
FR
28868,
May
26,
1998)
and
the
NODA
(
64
FR
10596;
March
5,
1999).
The
significant
modifications
in
EPA
Method
1631,
Revision
B
are
the
change
of
the
sample
holding
time
(
from
6
months
to
28
days),
the
change
of
the
MS/
MSD
performance
criteria
(
for
recovery
from
75
 
125
percent
to
71
 
125
percent
recovery),
and
a
change
in
reporting
requirements.

A.
Holding
Time
Change
EPA
proposed
the
6
month
holding
time
for
preserved
aqueous
samples
to
be
analyzed
by
EPA
Method
1631.
Because
the
6
month
holding
time
was
not
evaluated
in
the
method
validation
study
supporting
the
proposal,
EPA
requested
data
that
would
support
the
6
month
holding
time.
Data
were
not
available.
Therefore,
in
the
version
of
EPA
Method
1631
being
approved
for
use
today,
EPA
has
set
the
holding
time
to
28
days,
the
prescribed
holding
time
listed
in
Table
II
at
40
CFR
part
136.

B.
Performance
Criteria
Change
The
MS/
MSD
recovery
limits
in
the
proposed
version
of
EPA
Method
1631
were
75
 
125
percent.
The
interlaboratory
method
validation
study
produced
MS/
MSD
limits
of
71
 
119
percent.
In
response
to
comments
on
the
proposal,
EPA
acknowledges
that
the
lower
limit
produced
in
the
interlaboratory
study
is
more
appropriate
and
has
changed
this
limit
to
71
percent
in
the
version
of
EPA
Method
1631
approved
for
use
today.

C.
Reporting
Requirements
Change
1.
Reporting
of
Data
That
Failed
To
Meet
QC
Acceptance
Criteria
In
order
to
clarify
the
Agency's
intent
regarding
data
that
do
not
meet
the
method
QC
acceptance
criteria
or
that
indicate
the
analytical
system
is
not
in
control,
EPA
has
adopted
suggestions
from
commenters
that
these
data
should
not
be
reported
or
otherwise
used
for
permitting
or
regulatory
compliance
purposes.
This
modification
addresses
concerns
that
regulated
entities
could
be
adversely
affected
by
data
not
meeting
performance
criteria,
for
example,
via
compliance
monitoring.
EPA
also
has
added
a
statement
to
section
13.2
of
the
method
that
any
decision
not
to
report
data
from
an
analytical
system
that
is
out
of
control
does
not
provide
relief
from
a
permit's
underlying
requirement
to
submit
timely
reports.

2.
Reporting
of
Blank
Results
In
today's
rule,
EPA
has
expanded
reporting
of
blank
results
to
include
reagent
blanks
and
field
blanks
so
that
a
regulatory
authority
may
consider
field
blank
contamination
in
any
compliance
determination.
To
facilitate
assessment
of
the
presence
and
extent
of
contamination,
the
Agency
has
revised
EPA
Method
1631
to
require
reporting
of
the
mercury
concentration
in
field
blanks
as
well
as
in
reagent
blanks.
Today's
rule,
however,
does
not
require
blank
subtraction.
Regulatory
authorities
or
other
data
users
may
subtract
the
concentration
of
mercury
in
field
blanks
or
reagent
blanks
if
subtraction
is
warranted
on
a
case­
bycase
basis.
Today's
rule
does
nothing,
however,
to
preclude
the
reporting
of
blank­
subtracted
results
in
addition
to
the
separate
reporting
of
results
from
samples
and
from
blanks.
3.
Reporting
Laboratory­
Specific
MDLS
and
MLS
EPA
has
removed
the
option
for
laboratories
to
calculate
their
own
lower
MDLs
and
MLs
in
the
version
of
EPA
Method
1631
being
approved
for
use
today.
EPA
believes
this
will
avoid
confusion
and
preclude
lower
MDLs
and
MLs
from
being
used
for
NPDES
permitting
or
regulatory
compliance
determinations.

D.
Other
Changes
and
Improvements
1.
Changes
To
Method
Implementation
Minor
technical
improvements
were
made
to
EPA
Method
1631
to
clarify
method
implementation.
Changes
and
improvements
include:

·
Revision
to
sections
7.9,
7.10
and
10.1.1.2
to
include
two
working
standards
(
0.10
ng/
mL
and
10.0
ng/
mL)
in
order
to
correct
inaccurate
standard
concentration
levels.

·
Language
changes
in
sections
4.4.1
and
9.3.4.1
to
address
iodide
interferences
that
have
been
identified
and
assessed
since
proposal.
This
modification
required
the
addition
of
a
reference
supporting
the
handling
of
iodide
interferences.
The
additional
reference
has
been
added
to
EPA
Method
1631
as
Reference
10.

·
Revisions
to
sections
9.4.2.2
and
11.1.1.2
to
include
a
requirement
that
a
reagent
blank
include
the
same
amount
of
reagent
as
the
sample
being
analyzed.

·
Revisions
to
section
11.1.1.2
to
include
recommendations
to
assure
that
complete
oxidation
has
occurred.

·
Where
appropriate,
the
word
``
analyst''
was
changed
to
``
laboratory''
to
acknowledge
that
various
sections
of
EPA
Method
1631
may
be
performed
by
different
analysts
in
the
same
laboratory.

2.
Corrections
To
Method
Minor
changes
were
made
to
correct
typographical
and
information
errors.
Nearly
all
of
the
corrections
are
the
result
of
comments
and
include:

·
In
section
9.1.2.1,
``
less
than''
was
changed
to
``
less
than
or
equal
to.''
A
method
modification
must
achieve
an
MDL
``
less
than
or
equal
to''
one­
third
the
compliance
limit
or
the
MDL.

·
In
section
12.4.1,
>
0.2
ng/
L
has
been
corrected
to
<
0.2
ng/
L.

·
In
Table
2,
(
s)
has
been
corrected
to
RSD
for
precision.

·
In
Table
1,
the
lowest
ambient
water
quality
criterion
has
been
corrected
from
1.8
ng/
L
(
human
health
criterion)
to
1.3
ng/
L
(
wildlife
criterion).
30421
Federal
Register
/
Vol.
64,
No.
109
/
Tuesday,
June
8,
1999
/
Rules
and
Regulations
The
lowest
WQC
for
the
Great
Lakes
is
1.3
ng/
L,
the
criterion
for
wildlife
protection
(
see
Table
4
to
40
CFR
part
132).
·
In
section
4.2,
Reference
5
has
been
changed
to
Reference
9,
which
is
a
paper
discussing
contamination
of
samples
by
dental
work
containing
mercury
amalgam
fittings.
·
References
10
through
20
in
the
proposed
version
of
EPA
Method
1631
have
been
changed
to
References
11
through
21
in
the
final
version
to
include
the
addition
of
a
new
Reference
10
addressing
handling
of
samples
containing
iodide
interferences.

3.
Clarifying
Statements
As
a
result
of
comments:
·
In
section
4.3.8.5,
a
statement
was
added
to
clarify
that
reagents
can
be
a
source
of
contamination.
·
Sections
4.3.8.2
and
5.3
were
modified
to
clarify
the
meaning
of
``
high''
concentration
of
mercury
and
to
caution
that
samples
containing
mercury
concentrations
greater
than
100
ng/
L
should
be
diluted
prior
to
bringing
them
into
the
clean
room
or
laboratory
dedicated
to
processing
trace
metals
samples
and
that
samples
containing
m
 
g/
L
concentrations
of
mercury
should
be
treated
as
hazardous.

4.
Additions
To
Health
and
Safety
Monitoring
and
Waste
Management
Today's
version
of
EPA
Method
1631
includes
two
additions
made
to
address
and
clarify
health
and
safety
monitoring
and
waste
management.
·
In
section
5.2,
EPA
added
a
recommendation
that
personal
hygiene
monitoring
should
be
performed
using
Occupational
Safety
and
Health
Administration
(
OSHA)
or
National
Institute
of
Occupational
Safety
and
Health
(
NIOSH)
approved
personal
hygiene
monitoring
methods.
·
In
section
15.1,
a
reference
was
added
to
address
waste
management
techniques:
Environmental
Management
Guide
for
Small
Laboratories
(
EPA
233
 
B
 
98
 
001).
None
of
the
changes
or
improvements
to
the
Method
discussed
above
warrant
re­
proposal
because
these
changes
merely
respond
to
public
comment
to
clarify,
correct
minor
errors,
or
otherwise
improve
the
Method.
None
of
these
changes
impair
method
performance
or
reliability.

V.
Public
Participation
and
Response
to
Comments
The
Agency
proposed
EPA
Method
1631
(``
Method
1631'';
or
``
the
Method'')
on
May
26,
1998
(
63
FR
28867).
The
comment
period
closed
on
July
27,
1998.
In
addition
to
providing
notice
of
the
Method,
the
proposal
also
solicited
information
and
data
that
might
be
relevant
to
the
Agency's
decisionmaking.
EPA
both
received
information
and
data
and
developed
additional
data
confirming
the
proposal.
EPA
issued
a
notice
of
data
availability
(
NODA)
and
request
for
comment
on
these
data
(
64
FR
10596;
March
5,
1999).
The
NODA
comment
period
closed
on
April
5,
1999.
During
the
NODA
comment
period,
EPA
again
solicited
additional
data
and
information
on
EPA
Method
1631.
EPA
received
more
than
500
detailed
comments
from
approximately
30
commenters.
Comments
ranged
from
praise
and
support
for
EPA
Method
1631
to
concern
about
the
possible
setting
of
compliance
limits
at
the
MDL
or
ML
and
suggestions
for
improving
the
technical
details
of
the
method.
EPA
appreciates
the
constructive
comments
and
suggestions
and
believes
that
today's
version
of
EPA
Method
1631
will
provide
reliable
data
for
compliance
monitoring.
A
summary
of
the
significant
comments
is
presented
below,
followed
by
EPA's
response.
See
the
Docket
for
a
complete
summary
of
the
detailed
comments
and
more
extensive
responses.
A
significant
report
received
during
the
comment
period
was
provided
by
the
Department
of
Environmental
Protection
(
DEP)
in
the
State
of
Maine
titled:
``
Mercury
in
Wastewater:
Discharges
to
the
Waters
of
the
State''
(
the
``
Maine
Report'').
The
Maine
Report
gives
details
and
results
of
analysis
of
104
ambient
water
samples
and
more
than
150
wastewater
samples
(
primarily
effluents)
using
the
proposed
version
of
EPA
Method
1631.
The
Maine
Report
is
exemplary
in
that
it
allowed
Maine's
DEP
to
assess
the
presence
and
concentration
of
mercury
Statewide,
and
will
allow
the
State
of
Maine
to
focus
its
resources
on
problem
areas
within
the
State.
The
Maine
Report
is
also
significant
because
it
provided
a
comprehensive
``
real
world''
assessment
of
the
measurement
capability
of
EPA
Method
1631.
The
Maine
Report
demonstrates
that
EPA
Method
1631
can
be
applied
successfully
to
determination
of
mercury
in
a
wide
variety
of
effluents
and
ambient
waters.
Of
particular
interest
is
that,
of
104
ambient
water
samples
tested,
no
sample
contained
mercury
at
a
concentration
greater
than
7
ng/
L.
Of
the
more
than
100
effluent
samples
tested,
only
one
contained
mercury
above
the
200
ng/
L
level
that
previously
approved
methods
for
mercury
could
have
measured.
EPA
has
placed
a
copy
of
the
Maine
Report
in
the
Docket
for
today's
final
rule.
EPA
recommends
that
all
persons
interested
in
making
reliable
mercury
measurements
in
ambient
water
and
discharges
read
the
Maine
Report.
EPA
publicly
thanks
the
State
of
Maine
and
particularly
the
Department
of
Environmental
Protection
for
its
contribution.
Comments
and
responses
are
organized
and
presented
by
subject
area.

1.
Support
for
EPA
Method
1631
Comment:
Commenters
strongly
support
the
need
to
reliably
measure
mercury
levels
in
ambient
waters.
The
method
is
technically
sound
and
the
chemistry
behind
the
method
is
superb.
The
Agency
should
move
aggressively
to
implement
this
method.
Permitting
authorities
and
others
should
take
the
necessary
steps
to
see
its
adoption
and
use.
EPA
Method
1631
will:
(
1)
Allow
gathering
of
the
type
of
information
crucial
to
understanding
mercury
in
the
environment;
(
2)
allow
better
analytical
information
on
the
levels
of
mercury
in
various
waters
to
help
decide
if
and
where
source
reduction
efforts
would
be
most
effective;
(
3)
allow
facilities
to
better
assess
actual
discharges
and
progress
in
reducing
mercury
in
effluents;
(
4)
allow
permitting
authorities
to
establish
appropriate
limits
based
on
ecological
or
human
health
endpoints,
rather
than
being
limited
by
the
less­
sensitive
analytical
techniques
routinely
utilized;
(
5)
allow
agencies
to
better
monitor
response
of
ambient
waters
to
mercury
reduction
initiatives;
(
6)
be
useful
for
situations
in
which
an
authority
or
facility
believes
that
results
obtained
with
currently
approved
methods
do
not
reflect
actual
levels
because
of
contamination
during
sample
collection,
handling,
and
analysis;
and
(
7)
allow
the
State
of
Wisconsin
to
meet
the
recommendations
of
the
``
Wisconsin
Strategy
for
Regulating
Mercury
in
Wastewater.''
The
Wisconsin
strategy
recommends
development
of
better
analytical
capability
to
adequately
quantify
the
level
of
mercury
at
effluent
levels
that
have
the
potential
to
cause
environmental
degradation.
Response:
EPA
appreciates
the
support
and,
in
particular,
the
recognition
that
a
method
for
measuring
mercury
at
ambient
water
quality
criteria
levels
is
overdue,
that
the
method
is
based
on
sound
science,
and
that
EPA
Method
1631
will
protect
dischargers
from
false
reports
that
mercury
is
present
in
an
effluent
when,
in
fact,
inadequate
sampling
and
laboratory
procedures
accounted
for
the
mercury
measured
in
the
sample.
30422
Federal
Register
/
Vol.
64,
No.
109
/
Tuesday,
June
8,
1999
/
Rules
and
Regulations
2.
Practicality
and
Cost
Impractical
and
Costly
Comment:
The
required
use
of
EPA
Method
1631
would
impose
an
economic
burden
on
industry,
would
force
purchase
of
expensive
new
equipment,
and
would
require
a
significant
increase
in
operating
expenses.
The
cost
of
a
Class
100
clean
room
is
$
50,000
 
$
200,000.
The
analytical
equipment
will
cost
$
10,000
 
$
45,000.
Fluoropolymer
bottles
will
cost
an
estimated
$
7,200.
The
bottle
cleaning
protocol
would
require
dedicated
laboratory
space
and
staff.
Additional
cost
will
be
incurred
for
training.
Response:
Not
every
facility
will
need
to
create
a
clean
room
and
bottle
cleaning
capacity,
because
commercial
laboratories
are
available
and
can
supply
clean
bottles.
In
a
study
conducted
by
Ford
Motor
Company,
the
cost
per
sample
analysis
was
in
the
range
of
$
50
 
$
80.
EPA's
experience
is
that
costs
per
sample
typically
range
between
$
50
to
$
110.
EPA
does
not
believe
that
this
cost
is
unreasonable.
If
a
facility
desires
to
establish
a
laboratory
for
analysis
using
EPA
Method
1631,
however,
EPA
has
provided
guidance
for
establishment
of
``
clean
spaces''
that
will
minimize
costs
in
establishing
a
``
clean''
facility
(
see
References
6
and
7
in
Method
1631).

Lack
of
Laboratory
Capability
Comment:
Relatively
few
laboratories
nationwide
currently
have
the
expertise
and
infrastructure
to
conduct
analysis
using
this
Method.
Response:
Not
every
laboratory
will
need
to
establish
the
capability
to
conduct
EPA
Method
1631.
Analytical
costs
are
likely
to
decrease
as
demand
for
and
use
of
the
Method
increases.
Today
more
than
ever,
laboratories
and
other
businesses
respond
rapidly
to
new
business
opportunities.
Therefore,
the
Agency
anticipates
that
capacity
will
develop
rapidly
as
the
demand
increases
for
analyses
by
EPA
Method
1631.

Sampling
With
EPA
Method
1669
Comment:
Required
use
of
the
radical
field
sampling
procedures
in
EPA
Sampling
Method
1669
to
support
EPA
Method
1631
would
significantly
increase
cost
and
staff
necessary
to
sample
for
mercury
analysis
alone.
One
additional
sampling
person
(
for
clean
hands/
dirty
hands)
and
ultraclean
sampling
protocols
will
cost
approximately
$
34,000.
Response:
Once
sampling
personnel
become
familiar
with
the
``
clean
hands/
dirty
hands''
technique
and
procedures
recommended
in
EPA
Methods
1631
and
1669,
sampling
for
mercury
can
proceed
quickly
and
efficiently.
EPA
does
not
believe
that
full­
time
sampling
personnel
will
be
needed.
EPA
anticipates
that
samples
may
need
to
be
collected
monthly,
quarterly,
or
yearly,
depending
on
the
facility
and
whether
mercury
is
measured
at
levels
of
concern.
Therefore,
the
actual
incremental
cost
for
collection
of
samples
using
the
techniques
suggested
in
EPA
Method
1669
will
be
small.

3.
EPA
Method
1631
Represents
a
Significant
Regulatory
Action
Significant
Regulatory
Action
Under
Executive
Order
12866
Comment:
The
proposed
rule
is
a
``
Significant
Regulatory
Action''
under
Executive
Order
12866
(
58
FR
51735,
Oct.
4,
1993).
Response:
It
has
been
determined
that
this
rule
is
a
significant
regulatory
action
and
was,
therefore,
reviewed
by
the
Office
of
Management
and
Budget
(
OMB).

Cost
Increase
Stated
in
Great
Lakes
Guidance
Comment:
EPA
acknowledged
in
Table
5
 
13
of
Assessment
of
Compliance
Costs
Resulting
from
Implementation
of
the
Final
Great
Lakes
Water
Quality
Guidance
(
the
``
Assessment
Document'')
that
the
annual
cost
could
increase
by
$
569.8
million
if
future
MDLs
became
10
times
lower
and
could
increase
by
$
882.5
million
if
future
MDLs
became
100
times
lower.
EPA
Method
1631
lists
an
MDL
1000
times
lower.
This
rule
should
be
subject
to
OMB
review.
Response:
The
estimated
compliance
cost
increases
in
the
Assessment
Document
referred
to
future
MDLs
for
all
toxic
pollutants
(
not
just
mercury)
assuming
MDLs
might
be
used
as
compliance
limits
(
and
the
MDL
used
for
compliance
evaluation).
The
Assessment
Document
states
that
the
minimum
level
(
ML),
not
the
MDL,
should
be
used
for
compliance
evaluation
when
the
WQBEL
is
below
the
detection
or
quantitation
limit
of
the
most
sensitive
analytical
method.
Today's
rule
implicates
neither
of
these
limits
(
MDL
nor
ML)
because
EPA
Method
1631
allows
reliable
measurements
below
the
lowest
ambient
water
quality
criterion
(
1.3
ng/
L)
in
the
final
Great
Lakes
Water
Quality
Guidance.
The
Assessment
Document
presumed
that
costs
would
increase
if
dischargers
were
required
to
meet
discharge
requirements
at
the
lower
MDLs,
not
that
it
would
cost
these
amounts
if
EPA
allowed
use
of
another
method
for
the
measurement
of
mercury.
In
any
event,
EPA
evaluated
compliance
costs
in
the
Great
Lakes
rulemaking
because
it
would
result
in
establishment
of
standards
of
compliance.
Today's
rule
does
not
set
standards
of
compliance,
only
standards
of
measurement
and
analysis.
This
rule
is
considered
a
significant
regulatory
action
and
was,
therefore,
reviewed
by
OMB.

Unfunded
Mandates
Reform
Act
Comment:
The
Unfunded
Mandates
Reform
Act
(
UMRA;
25
U.
S.
C.
1531,
Subchapter
II),
requires
assessment
of
the
effects
of
regulatory
actions
on
the
private
sector
and
preparation
of
a
statement
containing
qualitative/
quantitative
cost­
benefit
analysis
if
costs
are
expected
to
exceed
$
100
million.
EPA
should
perform
the
cost
and
benefit
assessments
because
existing
permits
require
the
use
of
the
most
sensitive
test
procedure.
Response:
EPA
acknowledges
that
some
permits
may
require
the
permittee
to
use
the
most
sensitive
test
procedure
available
at
the
time
of
permit
issuance,
for
example,
when
the
limit
is
below
detection
of
approved
methods.
Today's
rulemaking
does
not
automatically
change
permits
issued
prior
to
today.
The
only
costs
associated
with
today's
rule
are
analytical
costs,
not
compliance
costs.
Today's
rule
is
not
subject
to
the
requirements
of
sections
202
and
205
of
UMRA
because
it
does
not
contain
a
Federal
mandate
that
could
result
in
expenditures
of
$
100
million
or
more
for
State,
local,
and
tribal
governments,
in
the
aggregate,
or
the
private
sector
in
any
one
year.
EPA
estimates
the
incremental
analytical
costs
associated
with
the
use
of
EPA
Method
1631
instead
of
another
approved
method
for
mercury
to
be
less
than
$
2.6
million
per
year.
EPA
believes
that
this
rule
does
not
impose
any
regulatory
requirements
that
might
significantly
or
uniquely
affect
small
governments
because
the
rule
approves
an
additional
test
procedure
for
the
measurement
of
mercury
that
might
be
regulated
by
some
other
action
(
e.
g.,
a
permit
that
implements
a
State­
adopted
water
quality
standard).

Regulatory
Flexibility
Analysis
Comment:
The
Regulatory
Flexibility
Act
(
RFA)
requires
description
of
impact
of
regulatory
actions
on
small
entities.
EPA
is
incorrect
in
stating
that
the
rule
will
not
have
a
significant
economic
impact
on
small
facilities.
Commenters
request
that
the
rule
be
subject
to
OMB
review
and
a
regulatory
flexibility
analysis.
Response:
In
section
VI.
C.
of
the
proposal,
pursuant
to
section
605(
b)
of
30423
Federal
Register
/
Vol.
64,
No.
109
/
Tuesday,
June
8,
1999
/
Rules
and
Regulations
the
Regulatory
Flexibility
Act,
5
U.
S.
C.
605(
b),
the
Administrator
certified
that
this
rule
will
not
have
a
significant
economic
impact
on
a
substantial
number
of
small
entities.
This
regulation
approves
an
additional
test
procedure
(
analytical
method)
for
the
measurement
of
mercury
which
may
be
required
in
the
implementation
of
the
CWA
(
e.
g.,
issuance
of
permits
and/
or
establishment
of
WQS).
EPA
Method
1631
is
not
a
de
facto
replacement
for
EPA
Method
245.1
or
any
of
the
other
existing
EPA­
approved
methods.
EPA
anticipates
that
permit
writers
will
only
require
the
use
of
EPA
Method
1631
if
there
is
a
need
to
assess
effluents
or
ambient
water
at
the
low
levels
EPA
Method
1631
can
measure
or
after
a
determination
that
a
discharge
causes,
has
a
reasonable
potential
to
cause,
or
contribute
to
an
excursion
from
a
water
quality
criterion
for
mercury.
EPA
further
anticipates
that
the
incremental
analytical
costs
that
may
potentially
be
incurred
by
any
small
entity
with
low
mercury
limits
will
be
at
most
$
600
per
year,
assuming
monthly
monitoring.

4.
Regulatory
implications
Support
for
Use
in
Permitting
Comment:
EPA
should
require
immediate
implementation
of
the
new
method
and
should
require
States
to
begin
requiring
it
for
NPDES
compliance
as
soon
as
possible.
Response:
Today's
rule
authorizes
use
of
EPA
Method
1631
but
does
not
require
its
use
for
compliance
monitoring
or
any
other
uses.
The
Agency
developed
EPA
Method
1631
to
enable
reliable
measurement
of
water
samples
at
the
levels
established
in
water
quality
criteria.
Consequently,
EPA
expects
that
when
the
measurement
sensitivity
of
EPA
Method
1631
is
necessary
to
assess
and
implement
water
quality
controls
(
including
compliance
monitoring),
EPA
Method
1631
will
be
used.
If
and
when
other
methods
for
measuring
mercury
at
these
low
levels
are
promulgated
in
40
CFR
part
136
or
are
approved
under
the
procedures
at
40
CFR
136.4
and
136.5,
the
permitting
authority
would
have
discretion
to
determine
which
method
is
most
appropriate
under
the
circumstances.
States
that
are
authorized
to
administer
the
NPDES
program
must
require
use
of
40
CFR
part
136
methods.
EPA
recognizes
that
States
may
need
to
follow
State
procedures
to
adopt
changes
to
40
CFR
part
136
before
they
can
require
use
of
a
newly
promulgated
method
and
allows
States
a
reasonable
time
to
accomplish
this.
See
40
CFR
123.62(
e).
EPA
regulations
do
not
require
that
permits
be
reopened
to
include
a
new
analytical
method.
Instead,
the
permitting
authority
may
have
the
opportunity
to
reopen
the
permit
or
to
wait
until
the
permit
is
reissued
to
include
a
new
or
more
sensitive
analytical
method.
See
40
CFR
122.62(
a)(
2).

Best
Available
Sensitivity
Comment:
EPA
failed
to
acknowledge
that
many
existing
permits
require
the
permittee
to
use
the
test
method
with
the
lowest
detection
level.
Response:
EPA
recommends
that
EPA
Method
1631
be
used
only
for
situations
in
which
mercury
may
be
known
or
thought
to
be
the
cause
of
an
environmental
or
human
health
problem,
or
for
investigations
directed
at
determining
whether
a
problem
exists,
in
the
same
way
that
EPA
recommends
that
other
test
methods
be
used.
EPA
Method
1631
is
being
made
available
for
use
when
it
is
necessary
to
measure
mercury
concentrations
at
low
levels.
As
previously
explained,
existing
permit
requirements
to
use
the
most
sensitive
method
available
may
only
incorporate
the
most
sensitive
method
at
the
time
the
requirement
was
imposed,
not
methods
adopted
in
the
future.

Reporting
vs.
Use
of
Data
Comment:
EPA
Method
1631
states
that
results
need
not
be
reported
for
regulatory
compliance
purposes
if
the
results
do
not
satisfy
QC
acceptance
criteria.
The
Inter­
Industry
Analytical
Group
(
IIAG)
suggests
that
EPA
change
the
phrase
to
read:
``.
.
.
may
not
be
reported
or
otherwise
used
for
permitting
or
regulatory
compliance
purposes.''
IIAG
also
requests
that
EPA
clarify
that
results
from
tests
performed
with
an
analytical
system
that
is
not
in
control
also
should
not
be
reported
or
otherwise
used
for
permitting
or
regulatory
compliance
purposes.
Response:
EPA
has
adopted
IIAG's
suggested
wording,
and
changed
relevant
text
in
EPA
Method
1631
accordingly.
The
wording
changes
clarify
the
Agency's
intent
that
data
that
fail
to
meet
the
Method's
QC
acceptance
criteria
are
not
reliable
measurements
of
mercury.

Iodide
Interference
Comment:
The
Inter­
Industry
Analytical
Group
(
IIAG)
comments
that
EPA
fails
to
give
adequate
consideration
to
interferences
and
cites,
as
an
example,
an
iodide
interference
problem
encountered
by
GPU
Nuclear
Co.
(
GPU)
using
EPA
Method
245.1.
GPU
attributes
this
interference
to
formation
of
a
stable
complex
of
iodide
and
mercury
that
prevents
reduction
of
mercury
to
its
elemental
form
with
the
stannous
chloride
(
SnCl2)
reductant.
(
SnCl2
also
is
used
in
EPA
Method
1631).
GPU
has
overcome
the
problem
by
addition
of
a
small
amount
of
sodium
tetrahydroborate
to
aid
in
reduction
of
mercury.
Response:
EPA
did
not
claim
that
EPA
Method
245.1
was
free
from
test
interference.
The
claim
was
made
concerning
EPA
Method
1631.
EPA
Method
1631
uses
different
chemistry
than
EPA
Method
245.1.
In
EPA
Method
1631,
mercury
is
oxidized
to
Hg(
II)
with
bromine
monochloride,
pre­
reduced
with
ammonium
hydroxide
hydrochloride
(
NH2OH
·
HCl)
to
destroy
free
halogens,
then
reduced
with
SnCl2.
The
NH2OH
·
HCl
likely
plays
the
same
role
as
the
sodium
tetrahydroborate
in
GPU's
procedure.
EPA
has
now
received
a
report
that
high
concentrations
of
iodide
(>
40
mg/
L)
can
interfere
in
the
determination
of
mercury
using
EPA
Method
1631.
These
high
concentrations
can
occur
in
in­
process
streams
and
influents,
but
normally
would
not
be
encountered
in
treated
effluents.
To
allow
for
the
possibility
that
high
concentrations
of
iodide,
however,
and
the
possibility
that
other
substances
could
interfere
in
the
determination
of
mercury
using
EPA
Method
1631,
today's
version
of
EPA
Method
1631
acknowledges
that
test
interference
remain
a
slight
possibility.

Variability
and
Regulatory
Decisions
Comment:
The
Inter­
Industry
Analytical
Group
(
IIAG)
comments
that
EPA's
QC
acceptance
criteria
and
other
variability
must
be
taken
into
account
in
regulatory
decisions.
IIAG
cites
the
QC
acceptance
criteria
for
the
matrix
spike
and
matrix
spike
duplicate
(
MS/
MSD)
in
EPA
Method
1631
and
questions
EPA's
rationale
for
determining
that
such
a
wide
range
of
performance
is
acceptable,
given
the
harsh
regulatory
consequences
associated
with
excursion
of
permit
limitations.
IIAG
states
that
EPA
must
explain
why
such
variability
is
acceptable
and
how
regulators
are
required
to
account
for
that
variability
in
their
permitting
and/
or
compliance
decisions.
Response:
EPA
disagrees
that
QC
acceptance
criteria
are
``
wide.''
These
criteria
are
consistent
with,
or
narrower
than,
other
methods
for
measuring
pollutants
at
these
levels
(
see
for
example
the
QC
acceptance
criteria
for
EPA
Methods
608
and
1613
at
40
CFR
part
136,
appendix
A).
The
QC
acceptance
criteria
recognize
the
variability
expected
to
occur
among
laboratories.
The
EPA
developed
the
criteria
from
multiple,
single­
laboratory
30424
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Register
/
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64,
No.
109
/
Tuesday,
June
8,
1999
/
Rules
and
Regulations
data
and
verified
the
data
in
the
interlaboratory
study.
The
Agency
used
the
laboratory
data
to
develop
the
QC
acceptance
criteria
in
today's
rule.
Regarding
accounting
for
variability
in
permitting
and
compliance
decisions,
EPA's
technology­
based
rules
do
account
for
analytical
variability
because
measurement
variability
is
a
component
of
the
overall
variability
encountered
to
develop
the
rule
(
including
field
measurement).
Therefore,
no
additional
allowance
for
analytical
variability
is
appropriate.
For
water
quality
uses,
accommodation
for
the
effect
of
analytical
variability
is
less
routinized.
In
the
Technical
Support
Document
(
TSD)
for
Water
Qualitybased
Toxics
Control
(
EPA/
505/
2
 
90­
001),
EPA
noted
that
accounting
for
analytical
variability
in
establishing
permitting
requirements
can
result
on
the
one
hand,
in
failure
to
be
adequately
protective
of
the
wasteload
allocation
or,
on
the
other
hand,
to
be
overly
conservative.
Therefore,
EPA
recommended
against
any
additional
allowance
for
analytical
variability.
However,
EPA
currently
is
developing
guidance
on
accounting
for
analytical
variability
in
permitting
in
the
context
of
the
whole
effluent
toxicity
program.
When
finalized,
that
guidance
may
provide
the
basis
for
revising
the
position
taken
in
the
TSD
with
respect
to
accounting
for
analytical
variability
in
general.

5.
Retention
of
Approved
Methods
and
Approval
of
Additional
Methods
Support
as
Additional
Method,
With
Qualification
Comment:
Commenters
support
approval
of
EPA
Method
1631
if
it
is
an
addition
to
the
list
of
approved
methods
and
not
a
replacement
for
existing
methods,
especially
if
a
laboratory
can
demonstrate
that
it
can
achieve
low
ng/
L
detection
limits
(
including
needed
sensitivity)
with
one
of
the
presently
approved
methods.
Response:
Today's
rule
approves
EPA
Method
1631
as
an
additional
method
that
can
be
used
when
measurement
of
mercury
at
water
quality
criteria
levels
is
needed.
EPA
doubts
that
a
laboratory
can
achieve
the
low
levels
(
including
needed
sensitivity)
with
one
of
the
presently
approved
methods.
Typically,
the
MDL
of
a
method
should
be
an
order
of
magnitude
(
factor
of
10)
below
the
level
desired
for
measurement
(
e.
g.,
a
regulatory
compliance
limit,
or
any
water
quality
criterion)
so
that
contamination
can
be
detected
and
the
effects
of
contamination
evaluated.
If
the
detection
limit
is
at
or
near
the
level
desired
for
measurement,
it
would
be
difficult
to
determine
if
the
presence
of
the
substance
is
real
or
is
attributable
to
contamination.
The
capabilities
of
EPA
Method
1631
enable
such
an
evaluation.

Support
Continued
Use
of
Approved
Methods
Comment:
EPA
should
continue
to
allow
the
use
of
other
approved
methods.
Withdrawal
of
existing
methods
(
EPA
245.1,
245.5,
Standard
Method
3112B,
ASTM
D3223
 
91,
USGS
I
 
3462
 
85,
and
AOAC­
International
977.2)
would
be
disastrous.
There
would
be
serious
adverse
economic
ramifications
if
EPA
Methods
245.1
and
245.2
are
withdrawn.
EPA
Method
1631
should
not
be
imposed
on
the
private
sector
as
the
sole
method.
The
option
of
using
less
sensitive
methods
should
remain
where
EPA
Method
1631
sensitivity
is
not
needed.
Response:
Based
on
comments
received
and
the
points
made
in
those
comments,
today's
rule
allows
continued
use
of
the
presently
approved
methods
for
determination
of
mercury
when
those
methods
achieve
the
desired
measurement
objective.

Performance­
Based
Measurement
System
Comment:
The
performance­
based
measurement
system
(
PBMS)
as
applied
in
proposal
allows
for
sample
preparation
and
trapping
modifications,
but
does
not
allow
for
use
of
atomic
absorption.
EPA
should
accept
application
of
PBMS
for
a
different
absorbance
technique
when
it
can
achieve
needed
sensitivity.
Response:
EPA
proposed
to
implement
PBMS
in
its
water
measurement
programs
(
62
FR
14975,
March
28,
1997)
but
has
not
yet
promulgated
a
final
PBMS
rule.
EPA
anticipates
that
the
final
rule
will
allow
use
of
alternate
determinative
techniques
such
as
atomic
absorption.
Until
a
final
rule
is
promulgated,
however,
methods
approved
at
40
CFR
part
136
must
be
used
according
to
their
terms.
Approval
of
the
use
of
alternate
procedures,
such
as
alternate
determinative
techniques,
can
be
requested
through
the
alternate
test
procedure
provisions
described
at
40
CFR
136.4
and
136.5.

6.
Application
to
Wastewater
Matrices
Inapplicable
to
Effluent
Comment:
EPA
Method
1631
is
not
applicable
to
the
determination
of
mercury
in
effluents.
The
Method
should
contain
a
statement
that
it
is
not
intended
for
the
determination
of
concentrations
normally
found
in
industrial
discharges.
Language
in
an
earlier
version
of
EPA
Method
1631
(
January
1996)
stated
that
``
this
method
is
not
intended
for
determination
of
metals
at
concentrations
normally
found
in
treated
and
untreated
discharges
from
industrial
facilities.''
Response:
When
the
Agency
first
began
development
of
EPA
Method
1631,
the
method
description
contained
the
statement
that
it
was
applicable
to
ambient
monitoring
but
that
it
was
not
intended
for
application
to
industrial
discharges.
Since
then,
however,
in
studies
of
POTWs
along
the
Great
Lakes,
in
the
interlaboratory
validation
study,
and
in
other
recent
studies
(
Results
of
Method
1631
Application
to
Effluent
Matrices
(
March
1999)
and
Application
of
Method
1631
to
Industrial
and
Municipal
Effluents
(
December
1998)),
EPA
has
found
that
mercury
could
be
reliably
measured
at
low
levels
in
municipal
and
industrial
discharges.
For
this
reason,
and
because
some
States
requested
EPA
support
to
develop
the
method
for
measurement
of
municipal
and
industrial
discharges,
the
Agency
expanded
EPA
Method
1631
to
cover
wastewaters.
The
statement
regarding
restricted
use
of
EPA
Method
1631
was
deleted
from
the
January
1996
version.

Testing
One
Effluent
Is
Inadequate
Comment:
Testing
one
effluent
at
one
level
by
a
few
laboratories
is
not
an
appropriate
inter­
laboratory
study
for
general
NPDES
application.
Response:
The
Agency
validated
EPA
Method
1631
on
one
filtered
and
one
unfiltered
wastewater
matrix
in
the
interlaboratory
validation
study.
Subsequently
the
Agency
gathered
additional
effluent
data
in
response
to
comments
regarding
the
method's
applicability
to
wastewaters
generally.
EPA
made
these
data
available
in
a
notice
of
data
availability
on
March
5,
1999
(
64
FR
10596).
These
data
demonstrate
that
EPA
Method
1631
is
applicable
for
measurement
of
municipal
and
industrial
effluents.

7.
Detection
and
Quantitation
MDL
Is
Flawed
Comment:
Several
commenters
state
that
Agency
estimates
of
detection
and
quantitation
in
EPA
Method
1631
are
flawed.
The
estimates
cannot
be
achieved
in
real
world
use.
The
estimates
are
scientifically
unsound.
The
estimates
are
neither
realistic
nor
reproducible.
The
estimates
use
an
inappropriate
multiplication
factor.
They
overestimate
the
certainty
associated
with
measurements.
The
estimates
are
not
representative
of
expected
performance
by
qualified
laboratories.
They
are
not
a
valid
statistical
basis
for
predicting
laboratory
30425
Federal
Register
/
Vol.
64,
No.
109
/
Tuesday,
June
8,
1999
/
Rules
and
Regulations
performance.
The
estimates
were
based
on
spikes
into
reagent
water
instead
of
wastewaters.
The
estimates
do
not
consider
effluent
characteristics.
The
estimates
are
based
on
a
protocol
that
has
never
been
subjected
to
peer
review
and
public
comment.
The
estimates
do
not
reflect
the
performance
capability
of
laboratories
that
will
be
performing
compliance
monitoring.
Response:
EPA
disagrees
that
the
MDLs
and
MLs
in
EPA
Method
1631
were
developed
inappropriately.
EPA
Method
1631
employs
the
method
detection
limit
(
MDL)
(
see
40
CFR
part
136,
appendix
B).
The
MDL
is
defined
as
the
minimum
concentration
of
a
substance
that
can
be
measured
and
reported
with
99%
confidence
that
the
analyte
concentration
is
greater
than
zero
and
is
determined
from
analysis
of
a
sample
in
a
given
matrix
containing
the
analyte.
The
MDL
procedure
is
not
designed
to
control
``
false
positives''
or
``
false
negatives,''
allow
for
repetitive
testing,
or
predict
laboratory
performance.
However,
since
the
variability
of
the
blank
is
expected
to
be
approximately
equal
to
the
variability
at
the
MDL,
measurement
results
greater
than
the
MDL
are
unlikely
to
be
obtained
when
measuring
samples
that
do
not
contain
the
substance
of
interest.
In
effect,
the
MDL
can
be
used
to
control
the
rate
of
``
false
positives.''
Reagent
water
is
the
matrix
used
for
determining
the
MDL
performance
measure
of
a
method
because
(
1)
reagent
water
is
available
to
all
laboratories,
(
2)
reagent
water
allows
determination
of
the
lowest
concentration
of
a
substance
that
can
be
detected
absent
matrix
interferences,
and
(
3)
there
is
no
matrix
that
represents
all
wastewater
matrices.
Application
of
the
MDL
procedure
to
particular
methods
has
been
subject
to
peer
review
and
public
comment
with
every
MDL
that
EPA
publishes
in
nearly
every
chemical­
specific
method
proposed
in
the
Federal
Register
since
1984.
The
MDL
procedure
has
widespread
acceptance
and
use
throughout
the
analytical
community.
No
other
detection
or
quantitation
limit
procedure
or
concept
has
achieved
this
level
of
acceptance
and
use.
EPA
Method
1631
incorporates
the
concept
of
a
minimum
level
of
quantitation
(
ML),
which
is
the
lowest
level
at
which
an
analytical
system
is
expected
to
give
a
recognizable
signal
and
acceptable
calibration
point.
In
1994,
EPA
revised
its
use
of
the
ML
concept
to
10
times
the
standard
deviation
associated
with
the
MDL
in
order
to
be
more
consistent
with
the
limit
of
quantitation
(
LOQ)
of
the
American
Chemical
Society
(
ACS).
The
LOQ
is
based
on
a
standard
deviation
of
replicate
measurements
on
a
blank,
which
is
expected
to
be
approximately
equal
to
the
standard
deviation
of
replicate
measurements
at
the
MDL.
Therefore,
EPA
expects
the
ML
to
be
approximately
equal
to
the
LOQ.
Because
the
MDL
is
established
at
3.14
times
the
standard
deviation
associated
with
the
MDL
and
the
ML
is
10
time
the
standard
deviation
associated
with
the
MDL,
the
multiplier
between
the
MDL
and
ML
is
3.18.
EPA
believes
that
this
multiplier
is
consistent
with
other
multipliers
selected
for
the
purpose
of
quantitation
and
that
this
multiplier
is
therefore
appropriate.
Readers
are
referred
to
the
response
to
comments
document
in
the
Docket
for
today's
rulemaking
for
a
more
detailed
response.
EPA
plans
to
continue
to
examine
the
issues
of
detection
and
quantitation.
The
Agency
initiated
a
study
recently
to
examine
the
effects
of
error
from
various
analytical
systems
on
detection
and
quantitation,
and
plans
to
involve
the
public
in
the
application
of
the
data
being
gathered
to
develop
an
improved
approach,
if
such
an
approach
is
found
to
exist.

Use
of
the
MDL/
ML
Concepts
Violate
Administrative
Procedure
Act
Comment:
Commenters
opposed
EPA's
proposed
detection
and
quantitation
levels
because
EPA
did
not
provide
the
opportunity
for
review
and
comment
on
the
basis
for
the
proposed
decisions.
EPA's
proposal
neither
describes
the
origin
of
the
MDL
nor
explains
why
the
Agency
believes
that
it
is
an
acceptable
basis
for
developing
detection
levels
for
use
in
compliance
determinations.
Response:
The
MDL
concept
origin
is
an
article
published
in
the
peerreviewed
scientific
literature
in
1981
(
Environmental
Science
and
Technology
15
1426
 
1435).
The
MDL
procedure
has
been
used
in
EPA's
various
environmental
programs
since
it
was
published
at
40
CFR
Part
136,
Appendix
B
in
1984.
The
MDL
procedure
is
accepted
and
used
by
nearly
all
organizations
making
environmental
measurements.
Recently,
EPA
has
undertaken
data
gathering
that
should
allow
re­
examination
of
detection
and
quantitation
limits.
When
this
study
is
complete,
EPA
will
decide
if
the
MDL
and
ML
continue
to
be
appropriate
or
if
other
concepts
are
appropriate
for
EPA's
scientific
and
regulatory
purposes.
EPA
has
involved,
and
will
continue
to
involve,
stakeholders
in
this
process
and
in
EPA's
final
decision.
Until
other
detection
and
quantitation
limit
concepts
are
shown
to
be
more
appropriate,
EPA
will
continue
to
use
the
MDL
and
ML
for
the
reasons
stated
at
the
beginning
of
this
response,
in
other
responses,
and
in
other
rules.

MDL
Violates
A
1985
Judicial
Settlement
Comment:
A
commenter
noted
that,
in
a
judicial
settlement
in
1985,
EPA
agreed
that
the
MDL
procedure
published
at
40
CFR
part
136,
appendix
B,
was
intended
to
apply
exclusively
to
the
subset
of
the
test
methods
that
the
Agency
published
at
40
CFR
part
136,
appendix
A,
in
1984.
Thus,
the
commenter
argues
that,
if
EPA
uses
the
MDL
procedure
for
the
purpose
of
deriving
a
detection
level
for
EPA
Method
1631,
the
Agency
must
provide
the
public
an
opportunity
to
review
and
comment
on
that
decision.
As
justification
for
use
of
the
MDL,
EPA
gave
the
reasons
that
(
1)
laboratories
that
participated
in
the
EPA
Method
1631
study
were
able
to
calculate
an
MDL
at
least
as
low
as
that
achieved
in
an
earlier
study,
and
(
2)
the
MDL
is
well
below
the
lowest
water
quality
criterion
(
WQC)
in
the
National
Toxics
Rule
and
listed
in
the
final
water
quality
guidance
for
the
Great
Lakes
System.
The
commenter
argues
that
these
reasons
may
be
desirable
but
that
they
are
irrelevant
for
determining
an
appropriate
detection
level.
The
commenter
argues
that
EPA
must
first
confirm
that
good
laboratories
can
achieve
that
level.
Response:
The
commenter
is
correct
that,
in
1985,
EPA
agreed
in
a
settlement
that
the
MDL
procedure
at
40
CFR
part
136,
appendix
B,
was
applicable
to
the
40
CFR
part
136,
appendix
A
methods
only.
The
settlement,
however,
did
not
restrict
future
application
of
the
MDL
procedure,
nor
did
it
restrict
any
person's
right
to
challenge
the
Agency's
reliance
on
the
MDL
procedure
in
any
future
rulemaking.
EPA
provided
the
opportunity
for
comment
on
use
of
the
MDL
in
EPA
Method
1631.
EPA
believes
that
the
interlaboratory
validation
study
of
EPA
Method
1631
confirms
that
good
laboratories
can
achieve
the
detection
and
quantitation
levels
that
EPA
established
for
EPA
Method
1631.

Effluent
Study
Offers
No
Support
for
the
MDL
Performance
Measure
in
EPA
Method
1631
Comment:
If
the
intent
of
EPA's
effluent
study
was
to
determine
whether
MDL
calculations
are
influenced
by
the
sample
matrix,
EPA
should
have
used
a
matrix
more
representative
of
real
world
samples
rather
than
the
City
of
Eugene's
POTW
effluent.
The
mercury
level
in
the
City's
effluent
was
lower
than
in
any
30426
Federal
Register
/
Vol.
64,
No.
109
/
Tuesday,
June
8,
1999
/
Rules
and
Regulations
of
the
other
effluents
used
in
EPA's
study.
Response:
Step
3(
b)
of
the
MDL
procedure
at
40
CFR
part
136,
appendix
B
requires
that
the
measured
level
of
analyte
be
less
than
five
times
the
MDL.
The
MDL
in
EPA
Method
1631
is
0.2
ng/
L.
Five
times
the
MDL
is
1.0
ng/
L
and
therefore
the
concentration
of
mercury
in
the
MDL
study
needed
to
be
in
the
range
of
0.2
to
1.0
ng/
L.
The
measured
level
of
mercury
in
the
City
of
Eugene's
POTW
effluent
was
0.56
and
0.72
ng/
L,
based
on
data
collected
prior
to
the
MDL
study.
Therefore,
the
mercury
concentration
of
the
City's
sample
was
in
the
appropriate
range
for
the
MDL
study.
8.
Clean
techniques
Clean
Techniques
Should
Be
Required
Comment:
The
rule
should
require
clean
sampling,
handling,
and
analysis
when
EPA
Method
1631
is
used
and
the
Agency
should
develop
a
comprehensive
database
on
the
level
of
contamination
that
may
arise.
A
commenter
provided
a
list
of
sections
in
EPA
Method
1631
that
allow
discretion
but
that
the
commenter
believes
must
be
made
mandatory
to
assure
reliable
and
reproducible
results,
for
example,
if
government
inspectors
measure
the
same
sample
effluents.
The
commenter
argues
that
EPA
must
explain
its
rationale
for
deciding
that
certain
clean
techniques
are
mandatory
and
to
justify
its
decision
that
other
techniques
are
not
mandatory
and,
therefore,
can
be
left
to
the
discretion
of
enforcement
officials.
The
only
exception
to
required
use
of
clean
techniques
should
be
that
permittees
should
have
complete
discretion
as
to
the
use
of
such
techniques
because
the
failure
to
use
such
techniques
can
only
result
in
mercury
results
higher
than
the
level
actually
present
in
an
effluent.
Response:
During
the
development
of
EPA
Method
1631,
the
Agency
found
some
researchers
using
very
extensive
measures
for
clean
sampling,
including
the
wearing
of
clean
room
caps,
suits,
booties,
and
shoulder­
length
gloves
in
addition
to
hand­
length
gloves.
On
the
other
hand,
EPA
found
other
researchers
wearing
shorts,
tee
shirts,
and
handlength
gloves
only.
Because
the
Agency
sought
to
maximize
the
flexibility
of
capable
personnel,
EPA
provided
the
Sampling
Guidance
(
EPA
Method
1669)
to
indicate
measures
to
prevent
and
preclude
contamination.
The
sampling
guidance
is
not
mandatory
for
use
with
EPA
Method
1631
because
some
permittees
and
sampling
teams
are
capable
of
reliable
sample
collection
without
the
measures
detailed
in
the
guidance.
The
rigor
of
clean
sample
collection
techniques
is
determined
by
the
required
measurement
objective
or
regulatory
level
(
i.
e.,
the
lower
the
desired
level,
the
more
critical
is
the
adherence
to
rigorous
clean
sampling
protocols).
Those
elements
of
clean
sampling,
handling,
and
analysis
that
the
Agency
believes
are
necessary
to
assure
reliable
and
reproducible
results
have
been
incorporated
into
EPA
Method
1631.
For
example,
the
use
of
clean
gloves
by
all
sampling
personnel
and
the
use
of
metal­
free
apparatus
are
requirements
specified
in
the
method.
In
addition,
the
QC
requirements
in
the
method
are
designed
to
detect
potential
contamination
that
may
arise
in
the
field,
during
transport,
or
in
the
laboratory.
Regarding
development
of
a
comprehensive
database,
the
Agency
does
not
see
the
need
to
develop
a
database
on
the
level
of
contamination
that
may
arise.
In
both
EPA
Method
1631
and
the
Sampling
Guidance
(
EPA
Method
1669),
EPA
is
very
explicit
that
contamination
is
a
concern
and,
consequently,
the
Agency
provided
appropriate
measures
to
minimize
contamination.
EPA
includes
a
number
of
mandatory
steps
in
a
method
when
it
believes
those
steps
are
necessary
to
provide
reliable
analytical
results.
If
EPA
were
to
justify
every
discretionary
aspect
of
a
method
(
indicated
by
the
words
``
should,''
or
``
may,''
and
other
words
denoting
suggestions)
for
every
method
or
guidance
document
that
the
Agency
develops,
method
and
document
development
would
grind
to
a
halt.
Parametric
studies
of
every
variable
that
could
possibly
influence
the
outcome
of
a
method
or
use
of
a
document
would
become
cost­
prohibitive.
The
list
of
discretionary
techniques
in
EPA
Method
1631
that
the
commenter
suggests
should
be
evaluated
would
require
20
parametric
studies.

Clean
Techniques
Should
Not
Be
Required
Comment:
Clean
techniques
should
not
be
required.
There
is
no
documentation
in
the
record
that
clean
field
blanks
and
clean
samples
can
be
collected.
This
casts
doubt
on
the
ability
of
laboratories
and
permittees
to
use
this
method
in
day­
to­
day
activities
designed
to
meet
Clean
Water
Act
requirements.
Clean
techniques
are
an
unnecessary
expense
because
detection
levels
this
low
are
not
needed
for
personal
or
environmental
protection.
EPA
Method
1631
is
able
to
detect
such
low
levels
that
sample
collection
and
analysis
must
occur
in
pristine
environments
to
prevent
false
positives.
Response:
Clean
techniques
are
not
required
but
are
recommended
for
low
level
mercury
measurements
associated
with
WQ
criteria.
EPA
cautions,
however,
that
contamination
has
been
identified
as
a
potential
problem
in
collecting
samples
for
mercury
prior
to
the
advent
of
clean
techniques.
Use
of
these
techniques,
as
detailed
in
the
sampling
guidance
(
EPA
Method
1669)
and
in
the
technical
literature
(
see
references
2
 
9
of
EPA
Method
1631),
has
allowed
collection
of
samples
free
of
contamination
at
ng/
L
levels.
EPA
urges
use
of
clean
techniques,
as
appropriate,
to
preclude
contamination.
As
stated
earlier,
those
elements
of
clean
sampling,
handling,
and
analysis
that
the
Agency
believes
are
necessary
to
assure
reliable
and
reproducible
results
have
been
incorporated
into
EPA
Method
1631.
Although
EPA
agrees
that
clean
techniques
should
not
be
(
and
are
not)
required,
EPA
disagrees
with
the
commenters
assertion
that
the
record
contains
no
documentation
that
clean
field
blanks
and
clean
samples
can
be
collected.
The
EPA
Method
1631
Interlaboratory
Study
included
the
collection
of
field
samples
for
use
in
the
study,
and
results
from
background
and
QC
analyses
demonstrated
the
ability
to
collect
clean
field
blanks
and
samples.
Following
proposal
of
the
method,
EPA
also
collected
additional
effluent
data
and
made
those
data,
including
QC
results,
available
in
the
Docket
and
through
a
notice
of
data
availability
(
64
FR
10596).
These
data
provide
further
demonstration
that
clean
field
blanks
and
clean
samples
can
be
collected.

9.
Corrections
to
statements
in
proposal
Holding
Time
Comment:
Proposed
EPA
Method
1631
lists
a
holding
time
of
6
months.
EPA
used
a
period
of
only
one
month,
however,
to
evaluate
the
stability
of
the
samples.
Please
provide
the
basis
for
the
large
variation
in
holding
times
between
EPA
Method
1631
(
6
months),
EPA
Method
245.1
(
28
days),
and
draft
EPA
Method
245.7
(
72
hours).
EPA
must
have
data
to
support
the
specified
maximum
holding
time
and
will
need
to
change
holding
time
in
CFR
if
EPA
Method
1631
is
approved.
Response:
EPA
specified
the
maximum
holding
time
at
6
months
in
the
proposed
version
of
EPA
Method
1631
based
on
statements
by
a
number
of
laboratories
involved
in
development
of
EPA
Method
1631
that
samples
could
be
held
for
this
period.
EPA
requested
data
that
would
support
the
6
month
holding
time.
Data
were
not
forthcoming.
Therefore,
in
today's
30427
Federal
Register
/
Vol.
64,
No.
109
/
Tuesday,
June
8,
1999
/
Rules
and
Regulations
version
of
Method
1631,
EPA
has
specified
a
maximum
holding
time
of
28
days,
consistent
with
Table
II
at
40
CFR
part
136.

Lowest
Water
Quality
Criterion
Comment:
The
lowest
water
quality
criterion
(
WQC)
for
the
Great
Lakes
Water
Quality
Guidance
is
not
1.8
ng/
L.
It
is
1.3
ng/
L,
the
criterion
for
wildlife
protection
(
see
Table
4
to
40
CFR
part
132).
Waters
of
the
United
States
frequently
exceed
these
levels
even
where
there
is
no
direct
industrial
or
municipal
discharge.
Response:
EPA
stands
corrected.
EPA
recognizes
that
waters
of
the
United
States
can
exceed
Great
Lakes
WQC
levels,
even
where
there
is
no
industrial
or
municipal
discharge.
That
possibility,
however,
does
not
affect
the
substance
of
today's
rule.

10.
Quality
Control
Excessive
quality
ControL
Comment:
The
quality
control
(
QC)
in
EPA
Method
1631
is
excessive,
unreasonable,
far
more
rigorous
than
in
currently
approved
methods,
and
demonstrates
the
inappropriateness
of
this
method
for
general
application.
Response:
The
QC
in
EPA
Method
1631
is
consistent
with
the
other
40
CFR
part
136,
appendix
A
methods
and
consistent
with
requirements
for
other
environmental
analytical
chemistry
methods.
EPA
believes
that
the
QC
requirements
are
necessary
to
ensure
the
reliability
of
data
results
and
that
these
requirements
are
not
onerous.

Insufficient
Quality
Control
Comment:
Without
addition
of
more
comprehensive
QC
for
background,
mercury
determinations
at
low
ppt
levels
are
subject
to
unknown
and
unacceptable
bias
and
imprecision.
Additional
validation
and
modification
to
the
QA/
QC
are
necessary
for
the
method
to
realize
its
potential
of
being
a
rugged
method
capable
of
providing
reliable
quantification
of
mercury
at
sub­
ng/
L
concentrations.
Response:
Bubbler
blanks,
reagent
blanks,
and
method
blanks
serve
as
checks
on
contamination.
The
MDL
performance
capacity
of
Method
1631
is
0.2
ng/
L.
This
MDL
enables
detection
of
contamination
at
sub­
ng/
L
concentrations,
should
such
contamination
occur.
A
discharger
or
laboratory
is
not
precluded
from
performing
additional
QC
if
it
desires.

Method
Performance
Comment:
A
commenter
argues
that
EPA
must
assure
that
the
irreducible
performance
limitations
inherent
in
all
methods
will
not
act
to
penalize
persons
for
lawful
conduct.
EPA
cannot
provide
such
assurances
absent
adequate
performance
data,
which
can
only
be
derived
from
properly
conducted
method
validation
studies.
If
EPA
determines
that
a
test
method
has
been
adequately
validated,
EPA
must
publish
performance
characteristics
along
with
the
method.
Response:
EPA
conducted
a
validation
study
on
EPA
Method
1631.
Published
method
performance
characteristics
associated
with
the
Method
include:
(
1)
A
method
detection
limit
(
MDL)
and
minimum
level
of
quantitation
(
ML)
in
Table
1,
(
2)
quality
control
(
QC)
acceptance
criteria
in
Table
2,
and
(
3)
precision
and
recovery
data
for
six
sample
types
in
Table
3.
These
data
more
than
adequately
support
the
adequacy
of
the
Agency's
validation
of
EPA
Method
1631.

11.
Blanks
and
Contamination
Reagent
Blanks
Comment:
Reagent
blanks
also
should
be
subtracted
from
sampling
results.
Otherwise,
inaccurate,
high
results
will
be
reported.
Response:
Section
12.4
in
EPA
Method
1631
asks
for
separate
reporting
of
results
for
samples
and
blanks,
unless
otherwise
requested
or
required
by
a
regulatory
authority
or
in
a
permit.
The
reason
for
separate
reporting
is
so
that
a
regulatory
authority
can
assess
if
results
for
samples
are
attributable
to
contamination
and
the
extent
to
which
contamination
is
affecting
the
measurement.
There
is
no
prohibition
in
EPA
Method
1631
against
reporting
blank­
subtracted
results,
provided,
of
course
that
results
for
blanks
and
samples
are
reported
separately.

Bubbler
and
Reagent
Blanks
Inadequate
Comment:
Bubbler
blanks
and
reagent
blanks
only
demonstrate
that
the
analytical
system
is
uncontaminated.
Analysis
of
field
or
equipment
blanks
should
not
be
used
to
demonstrate
laboratory
capabilities.
Response:
EPA
agrees
that
bubbler
blanks
and
reagent
blanks
are
used
to
demonstrate
that
the
analytical
system
is
uncontaminated.
EPA
disagrees
that
field
blanks
or
equipment
blanks
should
not
be
used
to
demonstrate
laboratory
capabilities.
The
laboratory
is
responsible
for
determining
and
reporting
field
contamination
and
for
demonstrating
that
equipment
blanks
are
free
from
contamination.
Section
9.4
of
EPA
Method
1631
also
contains
a
statement
``
it
is
suggested
that
additional
blanks
be
analyzed
as
necessary
to
pinpoint
sources
of
contamination
in,
and
external
to,
the
laboratory.''
Both
field
and
laboratory
contamination
sources
may
affect
the
analytical
results.

Blank
Subtraction
Comment:
It
should
be
acceptable
to
subtract
field
blank
results
in
addition
to
reagent
and
bubbler
blanks.
EPA
must
require
correction
for
reagent
blanks.
Response:
EPA
has
revised
section
12.4
of
the
method
to
ask
for
reporting
the
concentration
of
mercury
in
field
blanks
but
has
not
required
blank
subtraction
so
that
a
regulatory
authority
can
assess
if
results
for
samples
are
attributable
to
contamination
and
the
extent
to
which
contamination
is
affecting
the
measurement.
A
regulatory
authority
or
other
data
user
may
subtract
the
concentration
of
mercury
in
field
blanks
or
reagent
blanks
if
it
believes
this
subtraction
is
appropriate.
Today's
rule
does
not
preclude
the
reporting
of
blank­
subtracted
results
provided
that
results
for
samples
and
blanks
are
reported
separately.

Sample­
Specific
Reagent
Concentrations
Comment:
The
reagent
blank
does
not
address
sample­
specific
variation
in
reagent
concentrations.
Section
11.1.1.2
states
that
sewage
effluent
will
require
high
levels
of
bromine
monochloride
(
BrCl).
The
increased
requirement
for
BrCl
for
samples
high
in
organic
materials
could
increase
the
background
contribution
if
the
BrCl
contains
trace
amounts
of
mercury.
This
could
lead
to
a
high
bias
for
mercury
in
samples
that
require
high
levels
of
BrCl.
EPA
Method
1631
states
that
BrCl
cannot
be
purified
(
section
9.4.2.3).
Response:
EPA
agrees
and
has
added
the
requirement
that
whatever
concentration
or
amount
of
reagent
that
is
added
to
the
sample
must
also
be
added
to
the
reagent
blank
in
order
to
identify
the
reagent
as
a
potential
source
of
contamination.
Regarding
the
statement
in
EPA
Method
1631
that
BrCl
cannot
be
purified,
EPA
believes
that
this
statement
is
true.
BrCl,
however,
is
made
in
the
laboratory
from
several
reagents
that
can
be
obtained
in
highly
purified
form.
The
resulting
BrCl
will
then
be
very
pure.

12.
Validation
Study
Insufficient
Validation
Comment:
Insufficient
method
validation
has
been
provided
to
justify
method
use
for
routine
NPDES
purposes.
Response:
The
validation
steps
performed
with
EPA
Method
1631
are
30428
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/
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109
/
Tuesday,
June
8,
1999
/
Rules
and
Regulations
the
same
as
EPA
has
performed
with
many
other
methods.
The
Agency
validated
EPA
Method
1631
first
in
multiple
single­
laboratory
studies
and
then
further
validated
the
method
in
an
interlaboratory
study.
EPA
followed
ASTM
Practice
D
2777
in
the
interlaboratory
validation
study
design.
Some
members
of
the
ASTM
Committee
D
 
19
on
water
reviewed
the
interlaboratory
study
plan
and
contributed
to
the
study.
In
response
to
commenters
concerned
about
the
application
of
EPA
Method
1631
to
NPDES
effluents,
EPA
gathered
data
on
application
of
EPA
Method
1631
to
effluents
and
made
these
data
available
to
commenters
for
review
prior
to
today's
final
rule
(
64
FR
10596).

Validation
Under
Routine
Conditions
Comment:
Validation
data
results
were
not
obtained
under
normal,
routine
analytical
operations.
EPA
Method
1631
should
not
be
promulgated
until
it
is
validated
using
commercial
laboratories
able
to
sample
and
analyze
waste
streams
using
ultraclean
techniques.
The
fact
that
EPA
Method
1631
has
been
subjected
to
the
required
validation
studies
alone
does
not
ensure
that
it
is
ready
for
widespread
application.
Response:
Commercial
laboratories
were
included
in
the
interlaboratory
method
validation
study
and
all
laboratories
involved
in
the
study
perform
mercury
analyses
routinely
using
the
techniques
in
EPA
Method
1631.
It
is
not
necessary
for
commercial
laboratories
involved
in
the
analysis
of
samples
for
mercury
to
be
able
to
sample
waste
streams,
although
some
do.
All
laboratories
involved
in
the
interlaboratory
study
analyze
waste
streams
and
all
of
the
laboratories
involved
in
the
study
determined
their
respective
detection
limits.
EPA
believes
that
the
fact
that
EPA
Method
1631
has
been
subjected
to
the
required
validation
ensures
that
it
is
ready
for
widespread
application.
Over
time,
commercial
laboratories
will
develop
capacity
to
conduct
EPA
Method
1631
just
as
they
have
for
other,
previously
approved
test
methods.

Additional
Interlaboratory
Studies
Comment:
EPA's
intralaboratory
(
i.
e.,
within
laboratory)
studies
reported
in
the
Docket
with
the
NODA
failed
to
evaluate
the
matrix
issue
in
a
``
realworld
interlaboratory
context.
EPA
did
not
assess
interlaboratory
precision
and
bias
in
studies
included
with
the
NODA.
EPA's
data
are
insufficient
to
characterize
precision
and
bias
of
mercury
measurements
in
industrial
effluents.
Although
the
study
included
analysis
of
mercury
samples
by
multiple
laboratories,
none
of
the
samples
was
split
between
laboratories.
The
studies
should
have
been
designed
to
determine
interlaboratory
and
multi­
matrix
precision,
accuracy,
and
sensitivity
of
EPA
Method
1631.
Response:
Assessing
interlaboratory
precision
and
bias
was
not
an
objective
of
the
additional
studies.
EPA
assessed
interlaboratory
precision
in
the
interlaboratory
validation
study
and
published
performance
data
for
the
interlaboratory
validation
study
in
the
report
that
was
included
in
the
Docket
at
proposal.
In
comments
on
EPA's
proposal
of
EPA
Method
1631
on
May
26,
1998
(
63
FR
28867),
commenters
expressed
concern
that
only
one
municipal
secondary
effluent
had
been
analyzed
to
determine
precision
and
bias
and
that
no
industrial
wastewater
samples
were
analyzed.
They
argued
that
it
was
unreasonable
for
EPA
to
adopt
a
method
with
no
data
on
the
applicability
to
a
wide
variety
of
wastewater
matrices.
In
response
to
those
concerns,
the
Agency
applied
EPA
Method
1631
to
a
wide
variety
of
wastewater
matrices,
including
industrial
wastewater
samples.
EPA
gathered
data
generated
from
the
analyses
of
several
different
types
of
effluent
samples
in
order
to
determine
whether
the
results
from
that
study
meet
the
quality
control
(
QC)
acceptance
criteria
from
the
proposed
method.
EPA
developed
the
QC
acceptance
criteria
as
a
means
of
assuring
the
appropriate
levels
of
precision
and
bias.
Reevaluation
of
precision
and
bias
would
be
unnecessary
if
the
QC
acceptance
criteria
remained
appropriate.
The
commenters
claim
that
EPA
Method
1631
was
validated
inadequately
because
EPA
did
not
conduct
interlaboratory
method
validation
studies
on
a
wide
variety
of
wastewater
matrices
containing
naturally
occurring
mercury
levels
near
the
ML
of
EPA
Method
1631.
EPA
disagrees.
The
ASTM
guidelines
recommend
the
use
of
reagent
water
as
a
reference
matrix
in
at
least
one
environmental
sample
matrix
other
than
the
reference
matrix.
EPA
included
a
municipal
effluent
in
the
interlaboratory
validation
study.
It
would
be
impractical
to
use
a
wide
variety
of
wastewater
matrices
with
natural
concentration
near
the
ML
of
EPA
Method
1631
because
the
levels
in
the
sample
are
unknown
prior
to
analysis.
EPA
followed
ASTM
and
AOAC
guidelines
for
the
interlaboratory
method
validation
study
conducted
prior
to
proposal.
EPA
believes
that
the
Agency
has
fully
addressed
commenters'
requests
for
additional
data
on
the
application
of
EPA
Method
1631
to
wastewaters.
Commenters
that
have
requested
that
EPA
conduct
extensive
interlaboratory
studies
were
involved
in,
and
had
the
opportunity
to
contribute
to,
EPA's
interlaboratory
method
validation
study
at
the
time
it
was
conducted.
These
commenters
chose
not
to
contribute
to
a
more
extensive
study
or
conduct
studies
on
their
own.
EPA
reiterates
that
the
main
objective
in
conducting
the
additional
studies
was
to
demonstrate
that
effluent
samples
containing
mercury
at
or
near
the
ambient
water
quality
criteria
levels
given
in
the
National
Toxics
Rule
(
40
CFR
131.36)
and
in
the
Water
Quality
Guidance
for
the
Great
Lakes
System
(
40
CFR
part
132)
could
be
analyzed
with
little
or
no
difficulty.
Data
included
in
the
Docket
with
the
NODA
and
data
provided
by
the
State
of
Maine
demonstrate
that
these
measurements
can
be
made
reliably,
claims
from
commenters
about
interlaboratory
variability,
precision,
accuracy,
and
sensitivity
notwithstanding.

Insufficient
Concentrations
Comment:
A
commenter
argued
that
EPA
failed
to
validate
EPA
Method
1631
at
a
sufficient
number
of
concentrations.
The
commenter
cites
a
report
prepared
by
the
Electric
Power
Research
Institute
(
EPRI)
in
which
consultants
to
EPRI
cite
ASTM
Practice
D
2777
 
96
as
the
need
to
validate
the
method
using
samples
spiked
at
multiple
levels.
Response:
EPRI
and
EPA
collaborated
on
the
study
design
for
the
EPA
Method
1631
interlaboratory
validation
study.
EPA
shared
data
from
the
study
with
EPRI's
consultants
immediately
after
these
data
were
verified
and
validated.
The
consultants
acknowledge
the
collaboration
in
the
attachment
to
the
comment.
At
the
outset
of
the
study,
EPA
and
EPRI
agreed
on
the
limitations
of
the
study,
including
that
there
were
insufficient
resources
to
test
every
matrix
at
multiple
levels.
In
the
study,
EPA
validated
EPA
Method
1631
at
multiple
levels
in
reagent
water
and
in
freshwater
collected
near
Port
Washington,
Wisconsin.
To
support
today's
final
rule,
EPA
has
gathered
additional
data
on
a
variety
of
complex
effluents
using
EPA
Method
1631
and
evaluated
them
at
the
low
concentration
levels
of
interest
(
i.
e.,
low
parts
per
trillion).
These
data
represent
the
application
of
the
Method
to
``
real
world''
effluent
samples.
The
data
results
demonstrate
that
Method
1631
can
be
successfully
applied
to
effluents
because
all
of
the
matrix
spike
and
30429
Federal
Register
/
Vol.
64,
No.
109
/
Tuesday,
June
8,
1999
/
Rules
and
Regulations
matrix
spike
duplicate
(
MS/
MSD)
recoveries
were
within
the
QC
acceptance
criteria
in
EPA
Method
1631,
with
the
exception
of
two
samples
that
were
spiked
at
inappropriate
levels.

EPA
Did
Not
Follow
Voluntary
Consensus
Standards
Bodies
(
VCSB)
Procedures
Comment:
A
commenter
claims
that
EPA
failed
to
use
available
standards
and
practices
from
VCSBs
to
design
its
method
validation
study
as
required
by
the
National
Technology
Transfer
and
Advancement
Act
(
NTTAA)
and
Office
of
Management
and
Budget
(
OMB)
Circular
A
 
119.
The
commenter
asserts
that
NTTAA
makes
no
distinction
between
technical
standards
that
are
themselves
scientific
tests
(
i.
e.,
analytical
methods)
and
standards
used
in
the
evaluation
of
the
effectiveness
and
reliability
(
i.
e.,
validation)
of
those
tests.
The
commenter
states
that
EPA
claims
to
have
complied
with
NTTAA
by
developing
a
new
mercury
method
that
had
not
yet
been
developed
by
a
VCSB
and
that
EPA
incorrectly
claims
to
have
followed
VCSB
standards
for
the
design
and
conduct
of
its
validation
study.
Response:
EPA
agrees
that
NTTAA
and
OMB
Circular
A
 
119
require
federal
agencies
to
consider
available
VCSB
standards
and
practices.
NTTAA
requires
federal
agencies
to
consult
with
VCSBs
and
other
organizations
when
such
participation
is
in
the
public
interest
and
is
compatible
with
agency
missions,
authorities,
priorities,
and
budget
resources.
If
compliance
with
the
requirement
to
use
VCSB
standards
and
practices
is
inconsistent
with
applicable
law
or
otherwise
impractical,
a
federal
agency
may
elect
to
develop
technical
standards
not
developed
or
adopted
by
VCSBs
if
the
head
of
the
agency
or
department
transmits
to
OMB
an
explanation
of
the
reasons
for
using
other
standards.
EPA
disagrees
with
the
commenter's
statement
that
we
failed
to
use
available
standards
and
practices
from
VCSBs
to
design
its
method
validation
study.
EPA
designed
the
interlaboratory
study
with
participation
by
the
Electric
Power
Research
Institute
(
EPRI)
and
its
consultants.
Individuals
in
EPRI
are
members
of
ASTM
Committee
D
 
19
on
water.
Committee
D
 
19
developed
Practice
D
2777.
The
Agency
followed
Practice
D
2777
in
the
study
design.
Practice
D
2777
requires
the
use
of
at
least
one
representative
(``
reference'')
sample
matrix
which
is
the
same
for
all
laboratories
and
recommends
the
use
of
at
least
one
environmental
sample
matrix.
Reagent
water
is
recommended
as
the
reference
sample
matrix.
In
a
memorandum
attached
to
the
comment,
the
only
statement
suggesting
that
EPA
did
not
follow
Practice
D
2777
in
the
study
design
is
a
statement
that
Practice
D
2777
requires
Youden
pairs
at
a
minimum
of
three
concentrations
per
matrix.
EPA
included
four
concentration
pairs
in
reagent
water
(
and
an
unspiked
pair),
four
concentration
pairs
for
freshwater,
and
one
concentration
pair
each
for
marine
(
one
pair
filtered
and
one
pair
unfiltered)
and
for
a
municipal
effluent
(
one
pair
filtered
and
one
pair
unfiltered).
EPA
believes
that
the
design
of
its
validation
study
follows
ASTM
Practice
2777
 
96.
EPRI
members
were
aware
of
the
resource
limitations
of
the
study
and
agreed
that
the
design's
limited
number
of
Youden
pairs
and
blind
duplicate
samples
would
not
negate
the
usefulness
of
study
results.

Performance
Data
Are
Inadequate
and
Misleading
Comment:
A
commenter
argues
that
EPA's
performance
information
is
inadequate
and
misleading
because
it
fails
to
include
regression
equations.
Stakeholders
need
a
means
to
predict
how
EPA
Method
1631
will
perform
at
any
particular
level
within
its
working
range.
EPA
has
provided
regression
equations
in
other
methods.
EPA
inexplicably
departed
from
this
practice.
The
commenter
further
argues
that
EPA's
performance
information
is
inadequate
and
misleading
because
the
EPA
Method
1631
acceptance
criteria
are
inconsistent
with
study
results.
For
example,
test
data
can
be
used
if
the
initial
precision
and
recovery
falls
within
the
range
of
79
 
121
percent
which
is
broader
than
the
capability
(
86
 
113
percent)
demonstrated
by
the
EPA
Method
1631
interlaboratory
study.
EPA
must
explain
the
difference
in
the
final
rule,
if
only
to
avoid
confusion
in
the
interpretation
of
EPA
Method
1631
data.
Response:
EPA
disagrees
that
the
performance
information
is
inadequate
and
misleading.
As
EPA
has
stated
elsewhere
in
these
responses,
EPA
has
no
knowledge
of
use
of
regression
equations
in
the
interpretation
of
data
by
dischargers
or
others.
Regression
equations
are
redundant
with
QC
acceptance
criteria.
Regression
equations
can
be
used
to
calculate
expected
method
performance
at
a
given
concentration.
The
expected
performance
can,
in
turn,
be
used
to
determine
if
a
laboratory's
performance
is
equivalent
to
the
performance
of
laboratories
in
the
interlaboratory
study.
On
the
other
hand,
laboratories
that
practice
a
method
that
contains
QC
acceptance
criteria
recognize
these
criteria
as
absolute
standards
of
performance
within
which
the
method
must
operate.
Calculating
another
standard
of
performance,
as
the
commenter
suggests,
would
be
redundant.
Further,
because
the
QC
acceptance
criteria
are
an
absolute
standard,
laboratories
can
be
held
accountable.
If
they
fail
to
meet
this
standard,
corrective
action
would
be
required
followed
by
reanalysis
of
samples
after
the
QC
acceptance
criteria
are
met.
Standards
of
performance
derived
from
regression
equations
do
not
ensure
this
result.
The
difference
between
the
QC
acceptance
criteria
listed
in
proposed
EPA
Method
1631
and
in
Table
11
of
the
interlaboratory
study
report
are
attributable
to
EPA's
decision
to
not
tighten
the
acceptance
criteria
from
the
draft
method
published
in
1995
(
EPA
821
 
R
 
96
 
027).
EPA
is
concerned
that
any
method
that
is
iteratively
tested
may
result
in
ever
tightening
QC
acceptance
criteria
because
succeeding
data
gathered
with
the
method
will
likely
fall
within
these
criteria.
EPA
therefore
retained
the
QC
acceptance
criteria
from
the
draft
method
in
the
version
of
EPA
Method
1631
proposed.
In
contrast,
EPA
has
widened
the
QC
acceptance
criteria
for
the
matrix
spike
and
matrix
spike
duplicate
(
MS/
MSD)
between
the
proposed
version
and
today's
version.
The
reason
for
this
widening
is
that
the
data
gathered
in
the
interlaboratory
study
demonstrated
that
the
QC
acceptance
criteria
for
the
MS/
MSD
were
too
restrictive.
Making
certain
QC
acceptance
criteria
unreasonably
restrictive
is
onerous
upon
laboratories,
especially
new
laboratories
beginning
to
practice
a
method.
Therefore,
for
EPA
Method
1631,
the
Agency
decided
not
to
tighten
the
QC
acceptance
criteria
for
the
IPR
and
OPR,
and
loosened
the
QC
acceptance
criteria
for
the
MS/
MSD.

Mercury
Forms
and
Species
Comment:
Mercury
exists
in
many
forms
and
states.
The
interlaboratory
validation
study
failed
to
consider
molecular
diversity
of
mercury.
Response:
EPA
Method
1631
determines
total
mercury.
The
oxidation
step
in
EPA
Method
1631
oxidizes
all
commonly
occurring
forms
and
species
to
Hg(
II)
which
is
subsequently
reduced
to
volatile
Hg(
0)
so
that
it
can
be
purged
from
solution
and
determined.

13.
Technical
details
of
EPA
Method
1631
UV
Oxidation
Comment:
EPA
must
study
and
validate
EPA
Method
1631
with
UV
30430
Federal
Register
/
Vol.
64,
No.
109
/
Tuesday,
June
8,
1999
/
Rules
and
Regulations
oxidation
on
a
range
of
industrial
effluents
and
sewage
samples,
including
``
microbially­
rich''
samples.
Results
of
the
commenters'
studies
suggest
that
UV
photo­
oxidation
can
increase
recoveries
in
some
effluents.
The
use
of
UV
oxidation
makes
measurement
of
mercury
method­
defined.
Response:
In
section
3.1
of
EPA
Method
1631,
the
Agency
suggests
use
of
UV
oxidation
for
microbially­
rich
samples.
EPA
has
added
recommendations
for
determining
complete
oxidation.
These
recommendations
should
aid
in
recovery
of
mercury
from
some
samples,
as
the
commenter
suggests.
Regarding
all
interferences
not
being
oxidizable,
the
commenter
provided
no
example
of
a
non­
oxidizable
interference
that
could
occur
in
wastewaters.
Regarding
the
use
of
UV
oxidation
making
mercury
a
``
method­
defined
analyte,''
mercury
could
become
method­
defined
in
EPA
Method
1631
only
if
it
were
not
recovered
reliably
from
a
large
number
of
samples.
For
the
few
number
of
samples
in
which
incomplete
oxidation
can
occur
to
make
consideration
of
mercury
as
``
methoddefined
the
additional
recommendations
should
now
assure
complete
oxidation
so
that
mercury
does
not
need
to
be
considered
``
method­
defined.''
Total
mercury
can
be
determined
reliably.

Safety
Comment:
There
are
safety
hazards
inherent
in
the
practice
of
EPA
Method
1631.
The
preparation
of
bromine
monochloride
(
BrCl)
is
more
hazardous
than
preparation
of
potassium
permanganate
(
KmnO4).
A
significant
amount
of
hot
acid
is
involved
in
cleaning
bottles/
glassware.
Laboratory
ovens
will
be
destroyed
or
serve
as
a
source
of
contamination
as
a
result
of
cleaning
bottles
that
need
to
sit
overnight
at
60
 
70
°
C
with
HCl.
Further
clarification
and
explanation
is
requested
on
what
is
required
for
laboratory
personal
hygiene
monitoring.
Response:
Section
5
of
EPA
Method
1631
is
dedicated
to
safety
issues,
and
the
sampling
guidance
(
EPA
Method
1669)
contains
additional
information
on
safety.
Section
7.6
of
EPA
Method
1631
explicitly
states
that
BrCl
must
be
prepared
under
a
hood
because
copious
quantities
of
free
halogens
are
generated.
The
sampling
guidance
contains
detailed
procedures
for
bottle
cleaning
including
suggestions
for
a
heated
acid
vat
in
which
bottles
may
be
cleaned.
Use
of
metal
ovens
for
heating
acids
is
not
suggested
for
the
reason
that
the
commenter
states.
EPA
Method
1631
is
performance­
based,
however,
and
allows
laboratories
to
modify
the
cleaning
protocols
so
long
as
the
modified
protocols
are
capable
of
yielding
uncontaminated
equipment
blanks.
Regarding
personal
hygiene
monitoring,
EPA
has
added
the
statement
to
EPA
Method
1631
to
recommend
that
the
personal
hygiene
monitoring
be
performed
using
Occupational
Safety
and
Health
Administration
(
OSHA)
or
National
Institute
of
Occupational
Safety
and
Health
(
NIOSH)
approved
personal
hygiene
monitoring
methods.

14.
Miscellaneous
Toxicity
Limit
Comment:
The
fact
that
EPA
has
established
toxicity
limits
at
extremely
low
levels
by
a
means
not
based
on
laboratory
analyses
does
not
mean
that
analytical
technology
can
be
developed.
Response:
EPA
believes
that
ambient
water
quality
criteria
and
health
effectsbased
limits
can
best
be
supported
by
gathering
of
data
at
levels
represented
by
these
criteria
and
limits,
the
means
for
establishing
these
limits
notwithstanding.
EPA
will
continue
to
strive
to
develop
the
analytical
technology
that
will
allow
reliable
measurements
at
these
levels.

Dissolved
Mercury
Only
Comment:
EPA
should
clarify
that
EPA
Method
1631
applies
to
dissolved
mercury
only.
If
the
total
digestion
is
performed,
naturally
occurring
sediments
may
contribute
significant
analyte
concentrations
to
a
result.
Response:
Today's
rule
approves
use
of
EPA
Method
1631
for
determination
of
dissolved
and
total
mercury.
If
a
sample
contains
suspended
material
such
as
sediment,
it
is
intended
that
the
mercury
attached
to
or
contained
in
the
sediment
be
included
in
the
measurement.

Ambient
Criterion
Based
on
Methyl
Mercury
Comment:
The
ambient
water
quality
criterion
of
12
ng/
L
for
mercury
is
based
on
methyl
mercury.
EPA
incorrectly
implied
in
the
proposal
that
EPA
Method
1631
should
be
used
to
show
compliance
with
the
methyl
mercurybased
12
ng/
L
standard,
and
should
remove
reference
to
this
standard
if
the
method
is
finalized.
Response:
The
criterion
continuous
concentration
(
CCC)
of
12
ng/
L
is
for
total
recoverable
mercury
in
water
(
40
CFR
131.36(
b)(
1)).
Today's
rule
approves
EPA
Method
1631
so
that
reliable
measurements
of
mercury
can
be
made
at
this
level,
the
basis
for
the
standard
notwithstanding.
Both
``
total''
and
``
dissolved''
mercury
measurements
can
be
made
with
this
method.

Grab
Samples
Comment:
The
commenter
requests
that
EPA
provide
a
note
in
40
CFR
Part
136
that
requires
only
grab
samples
should
be
collected
when
using
EPA
Method
1631
because
of
potential
contamination
with
compositing
sampling
procedures.
Response:
EPA
has
not
mandated
use
of
grab
samples
because
EPA
does
not
wish
to
discourage
use
of
automated
compositing
equipment
or
sampling
by
other
means,
although
EPA
cautions
that
precluding
contamination
using
these
methods
is
more
difficult
than
with
collection
of
grab
samples.

Implementation
Comment:
A
commenter
argues
that
the
rulemaking
for
EPA
Method
1631
also
must
provide
an
objective
and
clear
description
regarding
how
the
Method
is
to
be
implemented
in
practice.
Response:
The
meaning
of
the
comment
is
unclear.
If
the
commenter
means
that
the
details
of
EPA
Method
1631
are
inadequate
and
the
procedures
in
EPA
Method
1631
need
to
be
developed
further,
EPA
believes
that
the
validation
study
demonstrates
that
the
procedures
in
EPA
Method
1631
are
more
than
adequate
for
implementation
of
EPA
Method
1631
in
practice.
If
the
commenter
means
that
EPA
must
examine
the
impact
of
the
measurements
made
by
the
method
on
the
regulatory
process,
EPA
believes
that
this
activity
is
outside
the
scope
of
method
development,
validation,
and
approval.
EPA's
regulations
for
water
pollution
control
are
based
on
wastewater
treatment
and
water
quality
considerations
as
required
by
the
Clean
Water
Act.
EPA
Method
1631
is
simply
a
tool
to
measure
total
mercury
in
aqueous
samples.

Personnel
Qualifications
Comment:
A
commenter
argues
that
EPA
should
specify
the
minimum
qualifications
for
persons
performing
EPA
Method
1631.
Section
4.3.2
of
EPA
Method
1631
states
that
it
is
imperative
that
the
procedures
be
carried
out
by
well­
trained,
experienced
personnel.
Response:
Section
1.10
states
that
EPA
Method
1631
``
should
be
used
only
by
analysts
who
are
experienced
in
the
use
of
CVAFS
techniques
and
who
are
trained
thoroughly
in
the
sample
handling
and
instrumental
techniques
described
in
this
Method.
Each
analyst
who
uses
this
Method
must
demonstrate
the
ability
to
generate
acceptable
results
using
the
procedure
in
section
9.2.''
30431
Federal
Register
/
Vol.
64,
No.
109
/
Tuesday,
June
8,
1999
/
Rules
and
Regulations
VI.
Regulatory
Requirements
A.
Executive
Order
12866
Under
Executive
Order
12866
(
58
FR
51735,
October
4,
1993),
the
Agency
must
determine
whether
a
regulatory
action
is
``
significant''
and
therefore
subject
to
OMB
review
and
the
requirements
of
the
Executive
Order.
The
Order
defines
``
significant
regulatory
action''
as
one
that
is
likely
to
result
in
a
rule
that
may:
(
1)
Have
an
annual
effect
on
the
economy
of
$
100
million
or
more
or
adversely
affect
in
a
material
way
the
economy,
a
sector
of
the
economy,
productivity,
competition,
jobs,
the
environment,
public
health
or
safety,
or
State,
local,
or
tribal
governments
or
communities;
(
2)
create
a
serious
inconsistency
or
otherwise
interfere
with
an
action
taken
or
planned
by
another
agency;
(
3)
materially
alter
the
budgetary
impact
of
entitlements,
grants,
user
fees,
or
loan
programs
or
the
rights
and
obligations
of
recipients
thereof;
or
(
4)
raise
novel
legal
or
policy
issues
arising
out
of
legal
mandates,
the
President's
priorities,
or
the
principles
set
forth
in
the
Executive
Order.''
Pursuant
to
the
terms
of
Executive
Order
12866,
it
has
been
determined
that
this
rule
is
a
``
significant
regulatory
action.''
As
such,
this
action
was
submitted
to
OMB
for
review.
OMB
made
no
suggestions
or
recommendations
on
this
rule.

B.
Unfunded
Mandates
Reform
Act
Title
II
of
the
Unfunded
Mandates
Reform
Act
of
1995
(
UMRA),
Pub.
L.
104
 
4,
establishes
requirements
for
Federal
agencies
to
assess
the
effects
of
their
regulatory
actions
on
State,
local,
and
tribal
governments
and
the
private
sector.
Under
section
202
of
the
UMRA,
EPA
generally
must
prepare
a
written
statement,
including
a
cost­
benefit
analysis,
for
proposed
and
final
rules
with
``
Federal
mandates''
that
may
result
in
expenditures
to
State,
local,
and
tribal
governments,
in
the
aggregate,
or
to
the
private
sector,
of
$
100
million
or
more
in
any
one
year.
Before
promulgating
an
EPA
rule
for
which
a
written
statement
is
needed,
section
205
of
the
UMRA
generally
requires
EPA
to
identify
and
consider
a
reasonable
number
of
regulatory
alternatives
and
adopt
the
least
costly,
most
costeffective
or
least
burdensome
alternative
that
achieves
the
objectives
of
the
rule.
The
provisions
of
section
205
do
not
apply
when
they
are
inconsistent
with
applicable
law.
Moreover,
section
205
allows
EPA
to
adopt
an
alternative
other
than
the
least
costly,
most
cost­
effective
or
least
burdensome
alternative
if
the
Administrator
publishes
with
the
final
rule
an
explanation
why
that
alternative
was
not
adopted.
Before
EPA
establishes
any
regulatory
requirements
that
significantly
or
uniquely
may
affect
small
governments,
including
tribal
governments,
it
must
have
developed
under
section
203
of
UMRA,
a
small
government
agency
plan.
The
plan
must
provide
for
notifying
potentially
affected
small
governments,
enabling
officials
of
affected
small
governments
to
have
meaningful
and
timely
input
in
the
development
of
EPA
regulatory
proposals
with
significant
federal
intergovernmental
mandates,
and
informing,
educating,
and
advising
small
governments
on
compliance
with
the
regulatory
requirements.
Today's
final
rule
does
not
contain
a
federal
mandate
(
under
the
regulatory
provisions
of
Title
II
of
the
UMRA)
for
State,
local,
or
tribal
governments
or
the
private
sector
that
may
result
in
expenditures
of
$
100
million
or
more
in
any
one
year.
EPA
has
determined
that
this
rule
contains
no
regulatory
requirements
that
significantly
or
uniquely
might
affect
small
governments.
As
discussed
below
under
the
Regulatory
Flexibility
Act,
the
economic
impact
on
small
entities
is
anticipated
to
be
small.
This
rule
makes
available
a
testing
procedure
which
would
be
used
at
the
discretion
of
the
permitting
authority
when
compliance
with
State­
adopted
water
quality
standards
necessitates
a
more
sensitive
method
than
those
previously
approved.
This
rule
would
impose
no
enforceable
duty
on
any
state,
local
or
tribal
governments
or
the
private
sector,
nor
would
it
significantly
or
uniquely
affect
them.
It
would
not
significantly
affect
them
because
any
incremental
costs
incurred
are
small
and
it
would
not
uniquely
affect
them
because
it
would
affect
all
size
entities
based
on
whether
testing
for
mercury
is
otherwise
required
by
a
regulatory
authority.
Further,
monitoring
for
small
entities
is
generally
expected
to
be
less
frequent
than
monitoring
for
larger
entities.
Therefore,
today's
rule
is
not
subject
to
the
requirements
of
sections
202,
203
and
205
of
UMRA.

C.
Regulatory
Flexibility
Act
Under
the
Regulatory
Flexibility
Act
(
RFA),
5
U.
S.
C.
601
et
seq.,
as
amended
by
the
Small
Business
Regulatory
Enforcement
Fairness
Act
(
SBREFA),
EPA
generally
is
required
to
conduct
a
regulatory
flexibility
analysis
describing
the
impact
of
the
regulatory
action
on
small
entities
as
part
of
rulemaking.
However,
under
section
605(
b)
of
the
RFA,
if
EPA
certifies
that
the
rule
will
not
have
a
significant
economic
impact
on
a
substantial
number
of
small
entities,
EPA
is
not
required
to
prepare
a
regulatory
flexibility
analysis.
Pursuant
to
section
605(
b)
of
the
Regulatory
Flexibility
Act,
5
U.
S.
C.
605(
b),
the
Administrator
certifies
that
this
rule
will
not
have
a
significant
economic
impact
on
a
substantial
number
of
small
entities.
This
regulation
approves
a
testing
procedure
for
the
measurement
of
mercury
which
EPA
anticipates
will
be
used
by
regulatory
authorities
when
a
permit
limit
has
been
set
below
the
level
of
detection
of
previously
approved
methods.
In
developing
this
regulation,
EPA
considered
the
effects
on
small
entities.
Section
601(
6)
of
the
RFA
defines
small
entity
as
small
business,
small
governmental
jurisdiction,
and
small
organization.
The
small
entities
that
might
be
affected
by
this
rule
include
small
governmental
jurisdictions
(
that
own
POTWs)
and
small
businesses
with
discharge
permits
for
mercury
at
or
below
200
ng/
L.
Of
the
477
entities
that
we
have
identified
with
mercury
limits
at
or
below
200
ng/
L,
143
are
businesses,
38
are
drinking
water
treatment
plants
in
Puerto
Rico,
and
296
are
POTWs.
To
evaluate
the
potential
impact
on
small
businesses,
EPA
first
assumed
that
all
of
the
143
businesses
were
small.
EPA
assigned
to
each
identified
facility
the
approximate
average
revenue
for
a
small
business
in
the
SIC
code
to
which
that
facility
belongs.
If
the
facility
is
classified
as
a
``
major''
discharger
in
the
Permit
Compliance
System
(
PCS),
EPA
assumed
incremental
analytical
monitoring
costs
of
$
5,200
per
year.
This
assumption
is
based
upon
weekly
monitoring
for
mercury
at
two
sample
locations
using
Method
1631,
and
assumes
each
facility
will
incur
an
incremental
cost
of
$
50
per
sample
(
the
high
end
of
the
range
of
incremental
costs).
If
the
facility
is
classified
as
a
``
minor''
discharger
in
PCS,
EPA
assumed
incremental
analytical
monitoring
costs
of
$
600
per
year.
This
assumption
is
based
upon
monthly
monitoring
for
mercury
at
one
sample
location
using
Method
1631,
and
again
assumes
each
facility
will
incur
the
high
end
incremental
cost
of
$
50
per
sample.
EPA
then
calculated
the
ratio
of
costs
(
using
these
upper­
bound
assumptions)
to
the
assigned
revenue
to
derive
an
upper­
bound
estimate
of
the
impacts.
The
ratio
is
above
0.5
percent
for
only
three
facilities
 
`
`
major''
facilities,
which
may
not
be
small
businesses
 
and
in
all
cases
is
below
4
percent.
On
average,
the
impacts
were
much
lower.
Specifically,
the
mean
ratio
for
all
of
the
facilities
is
0.17
percent
and
the
median
ratio
is
0.06
percent.
Although
PCS
contains
limitations
data
for
over
20
30432
Federal
Register
/
Vol.
64,
No.
109
/
Tuesday,
June
8,
1999
/
Rules
and
Regulations
percent
of
the
``
minor''
dischargers,
EPA
believes
that
``
minor''
dischargers
without
limitations
data
in
PCS
would
have
a
similarly
low
level
of
impact.
No
``
minor''
discharger
is
expected
to
experience
an
impact
of
more
than
0.5
percent
of
revenues.
Small
governments
are
those
representing
jurisdictions
of
less
than
50,000
people.
The
38
drinking
water
plants
in
Puerto
Rico
are
state­
owned
and
thus
are
not
small
governments.
To
evaluate
the
impact
on
small
POTWs,
EPA
looked
at
the
potential
impacts
on
two
sizes
of
POTWs
to
represent
both
``
major''
and
``
minor''
dischargers
potentially
affected
by
the
regulation.
Based
on
national
estimates
from
the
Census
of
Governments,
local
governments
collect
$
79.31
per
person
in
sewerage
charges,
which
EPA
assumed
to
be
the
average
per
capita
revenue
for
POTWs
from
the
population
that
they
serve.
On
average,
a
POTW
has
a
flow
of
100
gallons
per
day
for
each
person
that
it
serves.
EPA
assumed
that
a
POTW
serving
1,000
people
(
having
a
flow
of
100,000
gallons
per
day)
would
have
revenues
of
$
79,310
and
incur
costs
of
$
600
(
using
the
same
assumptions
as
for
``
minor''
businesses),
which
is
0.76
percent
of
its
revenue.
Similarly,
EPA
estimated
that
a
POTW
serving
10,000
people
(
having
a
flow
of
1
million
gallons
per
day,
and
thus
being
a
major
discharger)
would
have
revenue
of
$
793,100
and
incur
costs
of
$
5,200
(
using
the
same
assumptions
as
for
``
major''
businesses),
which
is
only
0.66
percent
of
revenue.
Based
upon
these
estimates,
EPA
concludes
that
this
rule
will
not
have
a
significant
economic
impact
on
a
substantial
number
of
small
entities.

D.
Paperwork
Reduction
Act
This
rule
contains
no
information
collection
requirements.
Therefore,
no
information
collection
request
has
been
submitted
to
the
Office
of
Management
and
Budget
(
OMB)
for
review
and
approval
under
the
Paperwork
Reduction
Act
of
1995,
44
U.
S.
C.
3501
et
seq.

E.
Submission
to
Congress
and
the
General
Accounting
Office
The
Congressional
Review
Act,
5
U.
S.
C.
801
et
seq.,
as
added
by
the
Small
Business
Regulatory
Enforcement
Fairness
Act
of
1996,
generally
provides
that
before
a
rule
may
take
effect,
the
agency
promulgating
the
rule
must
submit
a
rule
report,
which
includes
a
copy
of
the
rule,
to
each
House
of
the
Congress
and
to
the
Comptroller
General
of
the
United
States.
EPA
will
submit
a
report
containing
this
rule
and
other
required
information
to
the
U.
S.
Senate,
the
U.
S.
House
of
Representatives
and
the
Comptroller
General
of
the
United
States
prior
to
publication
of
the
rule
in
the
Federal
Register.
A
major
rule
cannot
take
effect
until
60
days
after
it
is
published
in
the
Federal
Register.
This
action
is
not
a
``
major
rule''
as
defined
by
5
U.
S.
C.
804(
2).
This
rule
will
be
effective
July
8,
1999.

F.
National
Technology
Transfer
and
Advancement
Act
As
noted
in
the
proposed
rule,
section
12(
d)
of
the
National
Technology
Transfer
and
Advancement
Act
of
1995
(
NTTAA),
Pub.
L.
104
 
113,
section
12(
d)
(
15
U.
S.
C.
272
note)
directs
EPA
to
use
voluntary
consensus
standards
in
its
regulatory
activities
unless
to
do
so
would
be
inconsistent
with
applicable
law
or
otherwise
impractical.
Voluntary
consensus
standards
are
technical
standards
(
e.
g.,
materials
specifications,
test
methods,
sampling
procedures,
business
practices)
that
are
developed
or
adopted
by
voluntary
consensus
standards
bodies.
The
NTTAA
directs
EPA
to
provide
Congress,
through
the
Office
of
Management
and
Budget
(
OMB),
explanations
when
the
Agency
decides
not
to
use
available
and
applicable
voluntary
consensus
standards.
This
rulemaking
involves
technical
standards.
Therefore,
the
Agency
conducted
a
search
to
identify
potentially
applicable
voluntary
consensus
standards.
EPA's
search
of
the
technical
literature
revealed
that
there
are
no
consensus
methods
for
determination
of
mercury
at
these
trace
levels,
although
the
American
Society
of
Testing
and
Materials
(
ASTM)
potentially
is
in
the
process
of
developing
an
analytical
method
for
the
determination
of
trace
levels
of
mercury.
If
ASTM
or
another
voluntary
consensus
standard
body
approves
such
a
method
and
EPA
believes
that
the
method
is
suitable
for
compliance
monitoring
and
other
purposes,
EPA
will
promulgate
the
method
in
a
subsequent
rule.
As
mentioned
earlier,
the
Agency
followed
ASTM's
Practice
D
2777
(
a
voluntary
consensus
standard)
in
the
design
of
EPA's
interlaboratory
method
validation
study
for
EPA
Method
1631.

G.
Executive
Order
13045
Executive
Order
13045,
``
Protection
of
Children
from
Environmental
Health
Risks
and
Safety
Risks,''
(
62
FR
19885,
April
23,
1997)
applies
to
any
rule
that:
(
1)
Is
determined
to
be
``
economically
significant''
as
defined
under
E.
O.
12866,
and
(
2)
concerns
an
environmental
health
or
safety
risk
that
EPA
has
reason
to
believe
may
have
a
disproportionate
effect
on
children.
If
the
regulatory
action
meets
both
criteria,
the
Agency
must
evaluate
the
environmental
health
or
safety
effects
of
the
planned
rule
on
children,
and
explain
why
the
planned
regulation
is
preferable
to
other
potentially
effective
and
reasonably
feasible
alternatives
considered
by
the
Agency.
EPA
interprets
E.
O.
13045
as
applying
only
to
those
regulatory
actions
that
are
based
on
health
or
safety
risks,
such
that
the
analysis
required
under
section
5­
501
of
the
Order
has
the
potential
to
influence
the
regulation.
Although
it
has
been
determined
that
this
rule
is
a
``
significant
regulatory
action''
under
E.
O.
12866,
it
is
not
economically
significant
and,
therefore,
E.
O.
13045
does
not
apply.
In
addition,
this
rule
does
not
establish
an
environmental
standard
intended
to
mitigate
health
or
safety
risks.

H.
Executive
Order
12875
Under
Executive
Order
12875,
``
Enhancing
the
Intergovernmental
Partnership,''
EPA
may
not
issue
a
regulation
that
is
not
required
by
statute
and
that
creates
a
mandate
upon
a
State,
local
or
tribal
government,
unless
the
Federal
government
provides
the
funds
necessary
to
pay
the
direct
compliance
costs
incurred
by
those
governments,
or
EPA
consults
with
those
governments.
If
EPA
complies
by
consulting,
E.
O.
12875
requires
EPA
to
provide
to
the
Office
of
Management
and
Budget
a
description
of
the
extent
of
EPA's
prior
consultation
with
representatives
of
affected
State,
local
and
tribal
governments,
the
nature
of
their
concerns,
any
written
communications
from
the
governments,
and
a
statement
supporting
the
need
to
issue
the
regulation.
In
addition,
Executive
Order
12875
requires
EPA
to
develop
an
effective
process
permitting
elected
officials
and
other
representatives
of
State,
local
and
tribal
governments
``
to
provide
meaningful
and
timely
input
in
the
development
of
regulatory
proposals
containing
significant
unfunded
mandates.''
Today's
rule
does
not
create
a
mandate
on
State,
local
or
tribal
governments.
States
have
been
particularly
supportive
of
EPA's
efforts
to
approve
a
more
sensitive
test
method
for
mercury.
The
rule
does
not
impose
any
enforceable
duties
on
these
entities.
This
rule
makes
available
a
testing
procedure
for
use
when
testing
is
otherwise
required
by
a
regulatory
agency.
Accordingly,
the
requirements
of
section
1(
a)
of
Executive
Order
12875
do
not
apply
to
this
rule.

I.
Executive
Order
13084
Under
Executive
Order
13084,
``
Consultation
and
Coordination
with
Indian
Tribal
Governments,''
EPA
may
30433
Federal
Register
/
Vol.
64,
No.
109
/
Tuesday,
June
8,
1999
/
Rules
and
Regulations
not
issue
a
regulation
that
is
not
required
by
statute,
that
significantly
or
uniquely
affects
the
communities
of
Indian
tribal
governments,
and
that
imposes
substantial
direct
compliance
costs
on
those
communities,
unless
the
Federal
government
provides
the
funds
necessary
to
pay
the
direct
compliance
costs
incurred
by
the
tribal
governments,
or
EPA
consults
with
those
governments.
If
EPA
complies
by
consulting,
E.
O.
13084
requires
EPA
to
provide
to
the
Office
of
Management
and
Budget,
in
a
separately
identified
section
of
the
preamble
to
the
rule,
a
description
of
the
extent
of
EPA's
prior
consultation
with
representatives
of
affected
tribal
governments,
a
summary
of
the
nature
of
their
concerns,
and
a
statement
supporting
the
need
to
issue
the
regulation.
In
addition,
Executive
Order
13084
requires
EPA
to
develop
an
effective
process
permitting
elected
and
other
representatives
of
Indian
tribal
governments
``
to
provide
meaningful
and
timely
input
in
the
development
of
regulatory
policies
on
matters
that
significantly
or
uniquely
affect
their
communities.''
As
described
under
the
Regulatory
Flexibility
Analysis,
today's
rule
does
not
significantly
or
uniquely
affect
the
communities
of
Indian
tribal
governments.
Further,
this
rule
does
not
impose
substantial
direct
compliance
costs
on
Tribal
governments.
This
rule
makes
available
a
testing
procedure
which
would
be
used
when
testing
is
otherwise
required
by
a
regulatory
agency
to
demonstrate
compliance
with
water
quality­
based
permit
limits
for
mercury.
Accordingly,
the
requirements
of
section
3(
b)
of
Executive
Order
13084
do
not
apply
to
this
rule.

List
of
Subjects
in
40
CFR
Part
136
Environmental
protection,
Analytical
methods,
Incorporation
by
reference,
Monitoring,
Reporting
and
recordkeeping
requirements,
Waste
treatment
and
disposal,
Water
pollution
control.
Dated:
May
28,
1999.
Carol
M.
Browner,
Administrator.

In
consideration
of
the
preceding,
USEPA
amends
40
Code
of
Federal
Regulations
part
136
as
follows:

PART
136
 
GUIDELINES
ESTABLISHING
TEST
PROCEDURES
FOR
THE
ANALYSIS
OF
POLLUTANTS
1.
The
authority
citation
of
40
CFR
part
136
continues
to
read
as
follows:

Authority:
Secs.
301,
304(
h),
307,
and
501(
a),
Pub.
L.
95
 
217,
Stat.
1566,
et
seq.
(
33
U.
S.
C.
1251,
et
seq.)
(
The
Federal
Water
Pollution
Control
Act
Amendments
of
1972
as
amended
by
the
Clean
Water
Act
of
1977).

2.
Section
136.3,
paragraph
(
a),
Table
IB.
 
List
of
Approved
Inorganic
Test
Procedures,
is
amended
by
revising
entry
35
to
read
as
follows:

§
136.3
Identification
of
test
procedures.

(
a)
*
*
*
*
*
*
*
*

TABLE
IB
 
LIST
OF
APPROVED
INORGANIC
TEST
PROCEDURES
Parameter,
units
and
method
Reference
(
method
number
or
page)

EPA1,35
STD
methods
18th
ed.
ASTM
USGS2
Other
*
*
*
*
*
*
*
35.
Mercury
 
Total,
4
mg/
L:
Cold
vapor,
manual,
or
.......................
245.1
3112
B
.....................
D3223
 
91
................
I
 
3462
 
85
................
3
977.22
Automated
...........................................
245.2
..................................
..................................
..................................
........................
Oxidation,
purge
and
trap,
and
cold
vapor
atomic
fluorescence
spectrometry
(
ng/
L).
43
1631
..................................
..................................
..................................
........................

*
*
*
*
*
*
*

Table
1B
Notes:
1
``
Methods
for
Chemical
Analysis
of
Water
and
Wastes,''
Environmental
Protection
Agency,
Environmental
Monitoring
Systems
Laboratory
 
Cincinnati
(
EMSL
 
CI),
EPA
 
600/
4
 
79
 
020,
Revised
March
1983
and
1979
where
applicable.
2
Fishman,
M.
J.,
et
al.
``
Methods
for
Analysis
of
Inorganic
Substances
in
Water
and
Fluvial
Sediments'',
U.
S.
Department
of
the
Interior,
Techniques
of
Water
 
Resource
Investigations
of
the
U.
S.
Geological
Survey,
Denver,
CO,
Revised
1989,
unless
otherwise
stated.
3
``
Official
Methods
of
Analysis
of
the
Association
of
Official
Analytical
Chemists,''
methods
manual,
15th
ed.
(
1990).
4
For
the
determination
of
total
metals
the
sample
is
not
filtered
before
processing.
A
digestion
procedure
is
required
to
solubilize
suspended
material
and
to
destroy
possible
organic­
metal
complexes.
Two
digestion
procedures
are
given
in
``
Methods
for
Chemical
Analysis
of
Water
and
Wastes,
1979
and
1983.''
One
(
Section
4.1.3),
is
a
vigorous
digestion
using
nitric
acid.
A
less
vigorous
digestion
using
nitric
and
hydrochloric
acids
(
Section
4.1.4)
is
preferred;
however,
the
analyst
should
be
cautioned
that
this
mild
digestion
may
not
suffice
for
all
sample
types.
Particularly
if
a
colorimetric
procedure
is
to
be
employed,
it
is
necessary
to
ensure
that
all
organo­
metallic
bonds
be
broken
so
that
the
metal
is
in
a
reactive
state.
In
those
situations,
the
vigorous
digestion
is
to
be
preferred
making
certain
that
at
no
time
does
the
sample
go
to
dryness.
Samples
containing
large
amounts
of
organic
materials
may
also
benefit
by
this
vigorous
digestion,
however,
vigorous
digestion
with
concentrated
nitric
acid
will
convert
antimony
and
tin
to
insoluble
oxides
and
render
them
unavailable
for
analysis.
Use
of
ICP/
AES
as
well
as
determinations
for
certain
elements
such
as
antimony,
arsenic,
the
noble
metals,
mercury,
selenium,
silver,
tin,
and
titanium
require
a
modified
sample
digestion
procedure
and
in
all
cases
the
method
write­
up
should
be
consulted
for
specific
instructions
and/
or
cautions.
Note
to
Table
IB
Note
4:
If
the
digestion
procedure
for
direct
aspiration
AA
included
in
one
of
the
other
approved
references
is
different
than
the
above,
the
EPA
procedure
must
be
used.
Dissolved
metals
are
defined
as
those
constituents
which
will
pass
through
a
0.45
micron
membrane
filter.
Following
filtration
of
the
sample,
the
referenced
procedure
for
total
metals
must
be
followed.
Sample
digestion
of
the
filtrate
for
dissolved
metals
(
or
digestion
of
the
original
sample
solution
for
total
metals)
may
be
omitted
for
AA
(
direct
aspiration
or
graphite
furnace)
and
ICP
analyses,
provided
the
sample
solution
to
be
analyzed
meets
the
following
criteria:
a.
has
a
low
COD
(<
20),
b.
is
visibly
transparent
with
a
turbidity
measurement
of
1
NTU
or
less,
c.
is
colorless
with
no
perceptible
odor,
and
d.
is
of
one
liquid
phase
and
free
of
particulate
or
suspended
matter
following
acidification.
*
*
*
*
*
35
Precision
and
recovery
statements
for
the
atomic
absorption
direct
aspiration
and
graphite
furnace
methods,
and
for
the
spectrophotometric
SDDC
method
for
arsenic
are
provided
in
Appendix
D
of
this
part
titled,
``
Precision
and
Recovery
Statements
for
Methods
for
Measuring
Metals.''
*
*
*
*
*
43
The
application
of
clean
techniques
described
in
EPA's
draft
Method
1669:
Sampling
Ambient
Water
for
Trace
Metals
at
EPA
Water
Quality
Criteria
Levels
(
EPA
 
821
 
R
 
96
 
011)
are
recommended
to
preclude
contamination
at
low­
level,
trace
metal
determinations.
30434
Federal
Register
/
Vol.
64,
No.
109
/
Tuesday,
June
8,
1999
/
Rules
and
Regulations
3.
Section
136.3
is
amended
by
adding
new
paragraph
(
40)
to
read
as
follows:

§
136.3
Identification
of
test
procedures.
(
a)
*
*
*
(
b)
*
*
*
*
*
*
*
*
(
40)
USEPA.
1999.
Method
1631,
Revision
B,
``
Mercury
in
Water
by
Oxidation,
Purge
and
Trap,
and
Cold
Vapor
Atomic
Fluorescence
Spectrometry.''
May
1999.
Office
of
Water,
U.
S.
Environmental
Protection
Agency
(
EPA
821
 
R
 
99
 
005).
Available
from:
National
Technical
Information
Service,
5285
Port
Royal
Road,
Springfield,
Virginia
22161.
Publication
No.
PB99
 
131989.
Cost:
$
25.50.
Table
IB,
Note
43.
*
*
*
*
*
[
FR
Doc.
99
 
14220
Filed
6
 
7
 
99;
8:
45
am]

BILLING
CODE
6560
 
50
 
P
ENVIRONMENTAL
PROTECTION
AGENCY
40
CFR
Part
239
[
FRL
 
6354
 
7]

Adequacy
of
State
Permit
Programs
Under
RCRA
Subtitle
D
AGENCY:
Environmental
Protection
Agency.
ACTION:
Direct
final
rule.

SUMMARY:
The
Environmental
Protection
Agency
(
EPA)
is
taking
direct
final
action
to
streamline
the
approval
process
for
specified
States
permit
programs
for
solid
waste
disposal
facilities
other
than
municipal
solid
waste
landfills
(
MSWLFs)
that
receive
conditionally
exempt
small
quantity
generator
(
CESQG)
hazardous
waste.
States
whose
subtitle
D
MSWLF
permit
programs
or
subtitle
C
hazardous
waste
management
programs
have
been
reviewed
and
approved
or
authorized
by
the
Agency
are
eligible
for
this
streamlined
approval
process
if
their
State
programs
require
the
disposal
of
CESQG
hazardous
waste
in
suitable
facilities.
EPA
is
issuing
an
adequacy
determination
to
the
following
State
programs:
Arizona,
California,
Colorado,
Connecticut,
Florida,
Georgia,
Illinois,
Kentucky,
Louisiana,
Massachusetts,
Michigan,
Minnesota,
New
Hampshire,
New
York,
North
Carolina,
North
Dakota,
Oklahoma,
Ohio,
Pennsylvania,
Rhode
Island,
South
Dakota,
Tennessee,
Utah,
Vermont,
Virginia,
West
Virginia,
Wisconsin,
and
Wyoming.
Elsewhere
in
the
proposed
rule
section
of
today's
Federal
Register,
EPA
is
proposing
the
program
adequacy
of
these
States
and
soliciting
comment
on
this
decision.
If
relevant
adverse
comments
are
received,
EPA
will
withdraw
this
direct
final
rule
of
program
adequacy
and
address
the
comments
in
a
subsequent
final
rule
document.
EPA
will
not
give
additional
opportunity
for
comment.
If
EPA
receives
relevant
adverse
comment
concerning
the
adequacy
of
only
certain
State
programs,
the
Agency's
withdrawal
of
the
direct
final
rule
will
only
apply
to
those
State
programs.
Comments
on
the
inclusion
or
exclusion
of
one
State
permit
program
will
not
affect
the
timing
of
the
decision
on
the
other
State
permit
programs.
DATES:
This
final
rule
will
become
effective
September
7,
1999,
unless
EPA
receives
relevant
adverse
comment
by
July
8,
1999.
Should
the
Agency
receive
such
relevant
adverse
comments,
EPA
will
withdraw
this
direct
final
rule
and
give
timely
notice
in
the
Federal
Register.
ADDRESSES:
Commenters
must
send
an
original
and
two
copies
of
their
comments
referencing
docket
number
F
 
98
 
SAPF
 
FFFFF
to:
RCRA
Docket
Information
Center,
Office
of
Solid
Waste
(
5305G),
U.
S.
Environmental
Protection
Agency
Headquarters
(
EPA,
HQ),
401
M
Street,
SW,
Washington,
D.
C.
20460.
Hand
deliveries
of
comments
should
be
made
to
the
Arlington,
VA,
address
listed
below.
Comments
may
also
be
submitted
electronically
by
sending
electronic
mail
through
the
Internet
to:
rcradocket
epamail.
epa.
gov.
Comments
in
electronic
format
should
also
be
identified
by
the
docket
number
F
 
98
 
SAPF
 
FFFFF.
All
electronic
comments
must
be
submitted
as
an
ASCII
file
avoiding
the
use
of
special
characters
and
any
form
of
encryption.
Commenters
should
not
submit
electronically
any
confidential
business
information
(
CBI).
An
original
and
two
copies
of
CBI
must
be
submitted
under
separate
cover
to:
RCRA
CBI
Document
Control
Officer,
Office
of
Solid
Waste
(
5305W),
U.
S.
EPA,
401
M
Street,
SW,
Washington,
D.
C.
20460.
Public
comments
are
available
for
viewing
in
the
RCRA
Information
Center
(
RIC),
located
at
Crystal
Gateway
I,
First
Floor,
1235
Jefferson
Davis
Highway,
Arlington,
VA.
The
RIC
is
open
from
9
a.
m.
to
4
p.
m.,
Monday
through
Friday,
excluding
federal
holidays.
To
review
docket
materials,
it
is
recommended
that
the
public
make
an
appointment
by
calling
703
 
603
 
9230.
The
public
may
copy
a
maximum
of
100
pages
from
any
regulatory
docket
at
no
charge.
Additional
copies
cost
$
0.15/
page.
For
information
on
accessing
paper
and/
or
electronic
copies
of
the
document,
see
the
SUPPLEMENTARY
INFORMATION
section.
Supporting
materials
for
the
final
determination
for
Connecticut,
Massachusetts,
New
Hampshire,
Rhode
Island,
and
Vermont
are
available
for
viewing
by
contacting
Cynthia
Greene,
US
EPA
Region
1,
90
Canal
Street,
Boston,
MA
02203,
phone
617/
565
 
3165.
Supporting
materials
for
the
final
determination
for
New
York
are
available
for
viewing
by
contacting
John
Filippelli,
US
EPA
Region
2,
290
Broadway,
New
York,
NY
10007
 
1866,
phone
212/
637
 
4125.
Supporting
materials
for
the
final
determination
for
Pennsylvania,
West
Virginia,
and
Virginia
are
available
for
viewing
by
contacting
Mike
Giuranna,
US
EPA
Region
3,
1650
Arch
Street,
Philadelphia,
PA
19103
 
2029,
phone
215/
814
 
3298.
Supporting
materials
for
the
final
determination
for
Florida,
Georgia,
Kentucky,
North
Carolina,
and
Tennessee
are
available
for
viewing
by
contacting
Patricia
Herbert,
US
EPA
Region
4,
Atlanta
Federal
Center,
61
Forsyth
Street,
Atlanta,
GA
30303
 
3104,
phone:
404/
562
 
8449.
Supporting
materials
for
the
final
determination
for
Illinois,
Michigan,
Minnesota,
Ohio,
and
Wisconsin
are
available
for
viewing
by
contacting
Mary
Setnicar,
US
EPA
Region
5,
77
West
Jackson
Blvd.,
Chicago,
IL
60604
 
3590,
phone
312/
886
 
0976.
Supporting
materials
for
the
final
determination
for
Louisiana
and
Oklahoma
are
available
for
viewing
by
contacting
Willie
Kelley,
US
EPA
Region
6,
1445
Ross
Avenue,
Dallas,
TX
75202
 
2733,
phone:
214/
665
 
6760.
Supporting
materials
for
the
final
determination
for
Colorado,
North
Dakota,
South
Dakota,
Utah,
and
Wyoming
are
available
for
viewing
by
contacting
Gerald
Allen,
Region
8,
US
EPA
999
18th
Street,
Suite
500,
Denver,
CO
80202
 
2466,
phone
303/
312
 
7008.
Supporting
materials
for
the
final
determination
for
Arizona
and
California
are
available
for
viewing
by
contacting
Steve
Wall,
US
EPA
Region
9,
75
Hawthorne
Street,
San
Francisco,
CA
94105,
phone
415/
744
 
2123.

FOR
FURTHER
INFORMATION
CONTACT:
For
general
information,
contact
the
RCRA
Hotline
at
800
424
 
9346
or
TDD
800/
553
 
7672
(
hearing
impaired).
In
the
Washington,
D.
C.,
metropolitan
area,
call
703/
412
 
9810
or
TDD
703/
412
 
3323.
For
information
on
specific
aspects
of
this
direct
final
rule,
contact
Allen
Geswein,
Municipal
and
Industrial
Solid
Waste
Division
of
the
Office
of