Document ID: EPA-HQ-OW-2003-0002-0107
Agency: epa
Document Type: Proposed Rule
Title: Guidelines Establishing Test Procedures for the Analysis of Pollutants; Procedures for Detection and Quantitation; Proposed Rule
Posted Date: 2003-03-12T05:00Z

11770
Federal
Register
/
Vol.
68,
No.
48
/
Wednesday,
March
12,
2003
/
Proposed
Rules
Alternative
Methods
of
Compliance
(
g)(
1)
An
alternative
method
of
compliance
or
adjustment
of
the
compliance
time
that
provides
an
acceptable
level
of
safety
may
be
used
if
approved
by
the
Manager,
Seattle
ACO.
Operators
shall
submit
their
requests
through
an
appropriate
FAA
Principal
Maintenance
Inspector,
who
may
add
comments
and
then
send
it
to
the
Manager,
Seattle
ACO.
(
2)
Alternative
methods
of
compliance,
approved
previously
per
AD
94
 
15
 
12,
amendment
39
 
8983,
are
approved
as
alternative
methods
of
compliance
with
paragraphs
(
a)
and
(
e)
of
this
AD.
(
3)
Alternative
methods
of
compliance,
approved
previously
per
AD
94
 
15
 
18,
amendment
39
 
8989,
are
approved
as
alternative
methods
of
compliance
with
paragraphs
(
b)
and
(
e)
of
this
AD.
(
4)
Alternative
methods
of
compliance,
approved
previously
per
AD
94
 
15
 
18
and
AD
94
 
15
 
12
that
provide
alternative
inspections
are
approved
as
alternative
methods
of
compliance
for
the
inspections
of
that
area
only
in
this
AD.
Note
6:
Information
concerning
the
existence
of
approved
alternative
methods
of
compliance
with
this
AD,
if
any,
may
be
obtained
from
the
Seattle
ACO.

Special
Flight
Permits
(
h)
Special
flight
permits
may
be
issued
per
sections
21.197
and
21.199
of
the
Federal
Aviation
Regulations
(
14
CFR
21.197
and
21.199)
to
operate
the
airplane
to
a
location
where
the
requirements
of
this
AD
can
be
accomplished.

Issued
in
Renton,
Washington,
on
March
5,
2003.
Ali
Bahrami,
Acting
Manager,
Transport
Airplane
Directorate,
Aircraft
Certification
Service.
[
FR
Doc.
03
 
5857
Filed
3
 
11
 
03;
8:
45
am]

BILLING
CODE
4910
 
13
 
P
DEPARTMENT
OF
LABOR
Mine
Safety
and
Health
Administration
30
CFR
Part
75
RIN
1219
 
AA76
Underground
Coal
Mine
Ventilation
 
Safety
Standards
for
the
Use
of
a
Belt
Entry
as
an
Intake
Air
Course
To
Ventilate
Working
Sections
and
Areas
Where
Mechanized
Mining
Equipment
Is
Being
Installed
or
Removed
AGENCY:
Mine
Safety
and
Health
Administration
(
MSHA),
Labor.
ACTION:
Change
of
hearing
dates.

SUMMARY:
MSHA
published
hearing
dates
in
the
January
27,
2003
proposed
rule
on
Safety
Standards
for
the
Use
of
a
Belt
Entry
as
an
Intake
Air
Course
to
Ventilate
Working
Sections
and
Areas
Where
Mechanized
Mining
Equipment
Is
Being
Installed
or
Removed
(
68
FR
3936).
Three
of
the
hearing
dates
published
with
the
proposed
rule
conflict
with
other
Agency
hearings
and
are
being
changed.
The
hearing
in
Grand
Junction,
Colorado
is
changed
from
May
29,
2003
to
April
3,
2003.
The
hearing
in
Charleston,
West
Virginia
is
changed
from
May
13,
2003
to
April
8,
2003.
The
hearing
in
Washington,
Pennsylvania
is
changed
from
May
15,
2003
to
April
10,
2003.
All
of
the
hearing
locations
are
printed
under
SUPPLEMENTARY
INFORMATION
for
the
convenience
of
the
public.

FOR
FURTHER
INFORMATION
CONTACT:
Marvin
W.
Nichols,
Jr.,
Director;
Office
of
Standards,
Regulations,
and
Variances,
MSHA;
phone:
(
202)
693
 
9440;
facsimile:
(
202)
693
 
9441;
E­
mail:
nichols­
marvin@
msha.
gov.

SUPPLEMENTARY
INFORMATION:

I.
Public
Hearings
The
table
contains
information
on
the
hearing
dates,
locations,
and
phone
numbers
for
all
of
the
hearings
on
``
Safety
Standards
for
the
Use
of
a
Belt
Entry
as
an
Intake
Air
Course
to
Ventilate
Working
Sections
and
Areas
Where
Mechanized
Mining
Equipment
is
Being
Installed
or
Removed.''

Date
Location
Phone
April
3,
2003
...............................
Holiday
Inn
Grand
Junction,
755
Horizon
Drive,
Grand
Junction,
CO
81506
.....................
(
970)
243
 
6790
April
8,
2003
...............................
Marriott
Town
Center,
200
Lee
Street,
Charleston,
WV
25301
...........................................
(
304)
345
 
6500
April
10,
2003
.............................
Holiday
Inn
at
the
Meadows,
340
Racetrack
Road,
Washington,
PA
15301
......................
(
724)
222
 
6200
April
29,
2003
.............................
Holiday
Inn
 
Birmingham
Airport,
5000
10th
Avenue
North,
Birmingham,
AL
35212
........
(
205)
591
 
6900
May
1,
2003
...............................
Holiday
Inn
Lexington
 
North,
1950
Newton
Pike,
Lexington,
KY
40305
...........................
(
859)
233
 
0512
Dated:
March
7,
2003.
Dave
D.
Lauriski,
Assistant
Secretary
of
Labor
for
Mine
Safety
and
Health.
[
FR
Doc.
03
 
5942
Filed
3
 
11
 
03;
8:
45
am]

BILLING
CODE
4510
 
43
 
P
ENVIRONMENTAL
PROTECTION
AGENCY
40
CFR
Part
136
[
FRL
 
7463
 
1]

RIN
2040
 
AD53
Guidelines
Establishing
Test
Procedures
for
the
Analysis
of
Pollutants;
Procedures
for
Detection
and
Quantitation
AGENCY:
Environmental
Protection
Agency
(
EPA).
ACTION:
Proposed
rule.
SUMMARY:
This
action
proposes
revisions
to
the
procedures
for
determining
the
sensitivity
of
analytical
(
test)
methods
under
EPA's
Clean
Water
Act
(
CWA).
EPA's
method
detection
limit
(
MDL)
and
minimum
level
of
quantitation
(
ML)
are
used
to
define
test
sensitivity
under
the
CWA.
The
MDL
is
used
to
determine
the
lowest
concentration
at
which
a
substance
is
detected
or
is
``
present''
in
a
sample.
The
ML
appears
in
many
EPA
methods
and
has
been
used
to
describe
the
lowest
concentration
of
a
substance
that
gives
a
recognizable
signal,
or
as
a
quantitation
limit.
The
proposed
revisions
include
clarifications
and
improvements
that
are
based
on
a
recent
EPA
assessment
of
the
MDL
and
the
ML
and
of
alternative
approaches
for
defining
test
sensitivity,
peer
review
of
the
Agency's
assessment,
and
earlier
stakeholder
comments
on
the
existing
MDL
procedure.
This
proposal
also
revises
the
definition
of
the
MDL
to
reflect
the
proposed
revisions
to
the
procedure.
The
Agency's
assessment
of
existing
EPA
procedures
for
determining
test
sensitivity
and
alternative
approaches
is
also
made
available
for
public
comment
in
a
separate
notice
in
today's
Federal
Register
(
see
Notice
of
Document
Availability
and
Public
Comment
Period
on
the
Technical
Support
Document
for
the
Assessment
of
Detection
and
Quantitation
Concepts).
DATES:
Comments
must
be
postmarked,
delivered
by
hand,
or
electronically
mailed
on
or
before
July
10,
2003.
Comments
provided
electronically
will
be
considered
timely
if
they
are
submitted
electronically
by
11:
59
p.
m.
Eastern
Time
on
July
10,
2003.
ADDRESSES:
Comments
may
be
submitted
by
mail
to
Water
Docket,
U.
S.
Environmental
Protection
Agency
(
4101T),
1200
Pennsylvania
Avenue
NW.,
Washington
DC
20460,
or
electronically
through
EPA
Dockets
at
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Federal
Register
/
Vol.
68,
No.
48
/
Wednesday,
March
12,
2003
/
Proposed
Rules
http://
www.
epa.
gov/
edocket/,
Attention
Docket
ID
No.
OW
 
2003
 
0002.
See
Unit
C
of
the
SUPPLEMENTARY
INFORMATION
section
for
additional
ways
to
submit
comments
and
more
detailed
instructions.

FOR
FURTHER
INFORMATION
CONTACT:
William
Telliard;
Engineering
and
Analysis
Division
(
4303T);
Office
of
Science
and
Technology;
Office
of
Water;
U.
S.
Environmental
Protection
Agency;
Ariel
Rios
Building;
1200
Pennsylvania
Avenue,
NW.;
Washington,
DC
20460,
or
call
(
202)
566
 
1061
or
E­
mail
at
telliard.
william@
epa.
gov.

SUPPLEMENTARY
INFORMATION:
A.
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
(
CWA).
In
doing
so,
NPDES
permitting
authorities,
including
States,
Territories,
and
Tribes,
make
several
discretionary
choices
when
they
write
the
permit.
These
choices
include
the
selection
of
pollutants
to
be
measured
and,
in
many
cases,
limited
in
permits.
If
EPA
has
``
approved''
(
i.
e.,
promulgated
through
rulemaking)
standardized
testing
procedures
under
40
CFR
part
136
for
the
analysis
of
a
given
pollutant,
the
NPDES
permit
must
include
one
of
the
approved
testing
procedures
or
an
approved
alternate
test
procedure.
The
testing
procedures
can
include
a
specification
for
detection
and
quantitation
levels
that
must
be
met.
Therefore,
entities
with
NPDES
permits
could
potentially
be
regulated
by
the
proposed
revisions
to
the
detection
and
quantitation
procedures
in
this
rulemaking.
In
addition,
when
an
authorized
State,
Territory,
or
Tribe
certifies
Federal
licenses
under
CWA
section
401,
they
must
use
the
standardized
testing
procedures
and
meet
the
associated
detection
and
quantitation
levels.
Categories
and
entities
that
could
potentially
be
regulated
include:

Category
Examples
of
potentially
regulated
entities
State,
Territorial,
and
Indian
Tribal
Governments
.............
States,
Territories,
and
Tribes
authorized
to
administer
the
NPDES
permitting
program
States,
Territories,
and
Tribes
providing
certification
under
Clean
Water
Act
section
401
Industry
...............................................................................
Facilities
that
must
conduct
monitoring
to
comply
with
NPDES
permits
Municipalities
......................................................................
POTWs
that
must
conduct
monitoring
to
comply
with
NPDES
permits
This
table
is
not
intended
to
be
exhaustive,
but
rather
provides
a
guide
for
readers
regarding
entities
likely
to
be
regulated
by
this
action.
This
table
lists
the
types
of
entities
that
EPA
is
now
aware
could
potentially
be
regulated
by
this
action.
Other
types
of
entities
not
listed
in
the
table
could
also
be
regulated.
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.

B.
How
Can
I
Get
Copies
of
This
Document
and
Other
Related
Information?
1.
Docket.
EPA
has
established
an
official
public
docket
for
this
action
under
Docket
ID
No.
OW
 
2003
 
0002.
The
official
public
docket
consists
of
the
documents
specifically
referenced
in
this
action,
any
public
comments
received,
and
other
information
related
to
this
action.
Although
a
part
of
the
official
docket,
the
public
docket
does
not
include
Confidential
Business
Information
(
CBI)
or
other
information
whose
disclosure
is
restricted
by
statute.
The
official
public
docket
is
the
collection
of
materials
that
is
available
for
public
viewing
at
the
Water
Docket
in
the
EPA
Docket
Center,
EPA
West
Building,
Room
B102,
1301
Constitution
Avenue
NW.,
Washington,
DC.
The
EPA
Docket
Center
Public
Reading
Room
is
open
from
8:
30
a.
m.
to
4:
30
p.
m.,
Monday
through
Friday,
excluding
legal
holidays.
The
telephone
number
for
the
Public
Reading
Room
is
(
202)
566
 
1744,
and
the
telephone
number
for
the
Water
Docket
is
(
202)
566
 
2426.
2.
Electronic
Access.
You
may
access
this
Federal
Register
document
electronically
through
the
EPA
Internet
under
the
``
Federal
Register''
listings
athttp://
www.
epa.
gov/
fedrgstr/.
An
electronic
version
of
the
public
docket
is
available
through
EPA's
electronic
public
docket
and
comment
system,
EPA
Dockets.
You
may
use
EPA
Dockets
at
http://
www.
epa.
gov/
edocket/
to
submit
or
view
public
comments,
to
access
the
index
listing
of
the
contents
of
the
official
public
docket,
and
to
access
those
documents
in
the
public
docket
that
are
available
electronically.
Once
in
the
system,
select
``
search,''
then
key
in
the
appropriate
docket
identification
number.
Certain
types
of
information
will
not
be
placed
in
the
EPA
Dockets.
Information
claimed
as
CBI
and
other
information
whose
disclosure
is
restricted
by
statute,
which
is
not
included
in
the
official
public
docket,
will
not
be
available
for
public
viewing
in
EPA's
electronic
public
docket.
EPA's
policy
is
that
copyrighted
material
will
not
be
placed
in
EPA's
electronic
public
docket
but
will
be
available
only
in
printed,
paper
form
in
the
official
public
docket.
Although
not
all
docket
materials
may
be
available
electronically,
you
may
still
access
any
of
the
publicly
available
docket
materials
through
the
docket
facility
identified
in
B.
1.
For
public
commenters,
it
is
important
to
note
that
EPA's
policy
is
that
public
comments,
whether
submitted
electronically
or
in
paper,
will
be
made
available
for
public
viewing
in
EPA's
electronic
public
docket
as
EPA
receives
them
and
without
change,
unless
the
comment
contains
copyrighted
material,
CBI,
or
other
information
whose
disclosure
is
restricted
by
statute.
When
EPA
identifies
a
comment
containing
copyrighted
material,
EPA
will
provide
a
reference
to
that
material
in
the
version
of
the
comment
that
is
placed
in
EPA's
electronic
public
docket.
The
entire
printed
comment,
including
the
copyrighted
material,
will
be
available
in
the
public
docket.
Public
comments
submitted
on
computer
disks
that
are
mailed
or
delivered
to
the
docket
will
be
transferred
to
EPA's
electronic
public
docket.
Public
comments
that
are
mailed
or
delivered
to
the
Docket
will
be
scanned
and
placed
in
EPA's
electronic
public
docket.
Where
practical,
physical
objects
will
be
photographed,
and
the
photograph
will
be
placed
in
EPA's
electronic
public
docket
along
with
a
brief
description
written
by
the
docket
staff.

C.
How
and
to
Whom
Do
I
Submit
Comments?
You
may
submit
comments
electronically,
by
mail,
or
through
hand
delivery/
courier.
To
ensure
proper
receipt
by
EPA,
identify
the
appropriate
docket
identification
number
in
the
subject
line
on
the
first
page
of
your
comment.
Please
ensure
that
your
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/
Vol.
68,
No.
48
/
Wednesday,
March
12,
2003
/
Proposed
Rules
comments
are
submitted
within
the
specified
comment
period.
Comments
received
after
the
close
of
the
comment
period
will
be
marked
``
late.''
EPA
is
not
required
to
consider
these
late
comments.
However,
late
comments
may
be
considered
if
time
permits.
1.
Electronically.
If
you
submit
an
electronic
comment
as
prescribed
below,
EPA
recommends
that
you
include
your
name,
mailing
address,
and
an
e­
mail
address
or
other
contact
information
in
the
body
of
your
comment.
Also
include
this
contact
information
on
the
outside
of
any
disk
or
CD
ROM
you
submit,
and
in
any
cover
letter
accompanying
the
disk
or
CD
ROM.
This
ensures
that
you
can
be
identified
as
the
submitter
of
the
comment
and
allows
EPA
to
contact
you
in
case
EPA
cannot
read
your
comment
due
to
technical
difficulties
or
needs
further
information
on
the
substance
of
your
comment.
EPA's
policy
is
that
EPA
will
not
edit
your
comment,
and
any
identifying
or
contact
information
provided
in
the
body
of
a
comment
will
be
included
as
part
of
the
comment
that
is
placed
in
the
official
public
docket,
and
made
available
in
EPA's
electronic
public
docket.
If
EPA
cannot
read
your
comment
due
to
technical
difficulties
and
cannot
contact
you
for
clarification,
EPA
may
not
be
able
to
consider
your
comment.
i.
EPA
Dockets.
Your
use
of
EPA's
electronic
public
docket
to
submit
comments
to
EPA
electronically
is
EPA's
preferred
method
for
receiving
comments.
Go
directly
to
EPA
Dockets
at
http://
www.
epa.
gov/
edocket,
and
follow
the
online
instructions
for
submitting
comments.
Once
in
the
system,
select
``
search,''
and
then
key
in
Docket
ID
No.
OW
 
2003
 
0002.
The
system
is
an
``
anonymous
access''
system,
which
means
EPA
will
not
know
your
identity,
e­
mail
address,
or
other
contact
information
unless
you
provide
it
in
the
body
of
your
comment.
ii.
E­
mail.
Comments
may
be
sent
by
electronic
mail
(
e­
mail)
to:
OWdocket
epamail.
epa.
gov,
Attention
Docket
ID
No.
OW
 
2003
 
0002.
In
contrast
to
EPA's
electronic
public
docket,
EPA's
e­
mail
system
is
not
an
``
anonymous
access''
system.
If
you
send
an
e­
mail
comment
directly
to
the
Docket
without
going
through
EPA's
electronic
public
docket,
EPA's
e­
mail
system
automatically
captures
your
email
address.
E­
mail
addresses
that
are
automatically
captured
by
EPA's
e­
mail
system
are
included
as
part
of
the
comment
that
is
placed
in
the
official
public
docket,
and
made
available
in
EPA's
electronic
public
docket.
iii.
Disk
or
CD
ROM.
You
may
submit
comments
on
a
disk
or
CD
ROM
that
you
mail
to
the
mailing
address
identified
in
Unit
C.
2.
These
electronic
submissions
will
be
accepted
in
WordPerfect
or
ASCII
file
format.
Avoid
the
use
of
special
characters
and
any
form
of
encryption.
2.
By
Mail.
Send
an
original
and
three
copies
of
your
comments
to
Water
Docket,
U.
S.
Environmental
Protection
Agency
(
4101T),
1200
Pennsylvania
Avenue
NW.,
Washington,
DC
20460,
Attention
Docket
ID
No.
OW
 
2003
 
0002.
3.
By
Hand
Delivery
or
Courier.
Deliver
your
comments
to
the
Water
Docket
Center,
EPA
West
Building,
Room
B102,
1301
Constitution
Avenue
NW.,
Washington,
DC,
Attention
Docket
ID
No.
OW
 
2003
 
0002.
Such
deliveries
are
only
accepted
during
the
Docket's
normal
hours
of
operation
as
identified
in
Unit
B.
1.

C.
How
Should
I
Submit
CBI
to
the
Agency?

Do
not
submit
information
that
you
consider
to
be
CBI
electronically
through
EPA's
electronic
public
docket
or
by
e­
mail.
You
may
claim
information
that
you
submit
to
EPA
as
CBI
by
marking
any
part
or
all
of
that
information
as
CBI
(
if
you
submit
CBI
on
disk
or
CD
ROM,
mark
the
outside
of
the
disk
or
CD
ROM
as
CBI
and
then
identify
electronically
within
the
disk
or
CD
ROM
the
specific
information
that
is
CBI).
Information
so
marked
will
not
be
disclosed
except
in
accordance
with
procedures
set
forth
in
40
CFR
part
2.
In
addition
to
one
complete
version
of
the
comment
that
includes
any
information
claimed
as
CBI,
a
copy
of
the
comment
that
does
not
contain
the
information
claimed
as
CBI
must
be
submitted
for
inclusion
in
the
public
docket
and
EPA's
electronic
public
docket.
If
you
submit
the
copy
that
does
not
contain
CBI
on
disk
or
CD
ROM,
mark
the
outside
of
the
disk
or
CD
ROM
clearly
that
it
does
not
contain
CBI.
Information
not
marked
as
CBI
will
be
included
in
the
public
docket
and
EPA's
electronic
public
docket
without
prior
notice.
If
you
have
any
questions
about
CBI
or
the
procedures
for
claiming
CBI,
please
consult
the
person
identified
in
the
FOR
FURTHER
INFORMATION
CONTACT
section.

D.
What
Should
I
Consider
as
I
Prepare
My
Comments
for
EPA
?

You
may
find
the
following
suggestions
helpful
for
preparing
your
comments:
1.
Explain
your
views
as
clearly
as
possible.
2.
Describe
any
assumptions
that
you
used.
3.
Provide
any
technical
information
and/
or
data
you
used
that
support
your
views.
4.
If
you
estimate
potential
burden
or
costs,
explain
how
you
arrived
at
your
estimate.
5.
Provide
specific
examples
to
illustrate
your
concerns.
6.
Offer
alternatives.
7.
Make
sure
to
submit
your
comments
by
the
comment
period
deadline.
8.
Ensure
proper
receipt
by
EPA
by
identifying
the
appropriate
docket
identification
number
in
the
subject
line
on
the
first
page
of
your
response.
It
would
also
be
helpful
if
you
provided
the
name,
date,
and
Federal
Register
citation
related
to
your
comments.

Outline
of
Document
I.
Statutory
Authority
II.
Purpose
of
This
Action
III.
Background
A.
Analytical
(
Test)
Methods
Used
for
CWA
Programs
B.
Settlement
Agreement
C.
Detection,
Quantitation,
and
Current
Controversy
D.
Historical
Use
of
Detection
and
Quantitation
Limits
under
the
Clean
Water
Act
IV.
EPA's
Assessment
of
Detection
and
Quantitation
Concepts
A.
Study
Plan
B.
Information
and
Data
Used
in
the
Assessment
C.
Concepts
and
Procedures
Included
in
the
Assessment
D.
Issues
Considered
during
the
Assessment
E.
Evaluation
Criteria
V.
EPA's
Findings
and
Conclusions
VI.
Peer
Review
of
EPA's
Assessment
VII.
Proposed
Revisions
to
the
MDL
and
ML
A.
Definition
of
the
Detection
Limit
B.
Technical
Revisions
to
the
MDL
Procedure
C.
Editorial
Changes
to
the
MDL
Procedure
D.
Definition
and
Procedure
for
Determining
the
Minimum
Level
of
Quantitation
E.
Acceptance
of
Test
Methods
Employing
Alternative
Detection
and
Quantitation
Procedures
VIII.
Industry
Proposal
IX.
Solicitation
of
Comments
X.
Statutory
and
Executive
Order
Reviews
A.
Executive
Order
12866:
Regulatory
Planning
and
Review
B.
Paperwork
Reduction
Act
C.
Regulatory
Flexibility
Act
D.
Unfunded
Mandates
Reform
Act
E.
Executive
Order
13132:
Federalism
F.
Executive
Order
13175:
Consultation
and
Coordination
with
Indian
Tribal
Governments
G.
Executive
Order
13045:
Protection
of
Children
from
Environmental
Health
&
Safety
Risks
H.
Executive
Order
13211:
Actions
that
Significantly
Affect
Energy
Supply,
Distribution,
or
Use
I.
National
Technology
Transfer
and
Advancement
Act
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Proposed
Rules
XI.
References
Appendix
A:
Definitions,
Acronyms,
and
Abbreviations
Used
in
This
Document
I.
Statutory
Authority
This
action
is
being
proposed
pursuant
to
the
authority
of
sections
301(
a),
304(
h),
and
501(
a)
of
the
Clean
Water
Act
(``
CWA''
or
the
``
Act''),
33
U.
S.
C.
1311(
a),
1314(
h),
1361(
a).
Section
301(
a)
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
application
pursuant
to
[
section
402
of
this
Act].''
Section
501(
a)
of
the
Act
authorizes
the
Administrator
to
``
prescribe
such
regulations
as
are
necessary
to
carry
out
this
function
under
[
the
Act].''
EPA
publishes
analytical
test
method
regulations
for
use
in
CWA
programs
at
40
CFR
part
136.
The
Administrator
has
made
these
test
methods
applicable
to
monitoring
and
reporting
of
NPDES
permits
(
40
CFR
122.21,
122.41,
122.44,
and
123.25),
and
implementation
of
the
pretreatment
standards
issued
under
section
307
of
the
Act
(
40
CFR
403.10
and
403.12).

II.
Purpose
of
This
Action
EPA
recently
completed
an
assessment
of
procedures
for
determining
the
sensitivity
of
analytical
test
methods
(
i.
e.,
procedures
for
determining
detection
and
quantitation)
and
their
application
to
Clean
Water
Act
Programs.
That
assessment
was
conducted
pursuant
to
a
settlement
agreement
with
the
Alliance
of
Automobile
Manufacturers,
et
al.
(
See
III.
B.
below
for
details.)
The
assessment
is
contained
in
a
document
entitled,
Technical
Support
Document
for
the
Assessment
of
Detection
and
Quantitation
Concepts
or
``
Assessment
Document''
(
EPA
821
 
R
 
03
 
005,
February,
2003).
A
draft
of
the
Assessment
Document
was
peerreviewed
in
August
2002
in
accordance
with
EPA
peer
review
guidelines.
Following
peer
review,
EPA
incorporated
peer
review
comments
into
the
Assessment
Document.
EPA
is
providing
an
opportunity
for
public
review
and
comment
on
the
assessment
and
the
Assessment
Document
through
this
notice
and
also
in
a
separate
notice
in
this
Federal
Register
(
see
Notice
of
Document
Availability
and
Public
Comment
Period
on
the
Technical
Support
Document
for
the
Assessment
of
Detection
and
Quantitation
Concepts).
Based
on
findings
from
the
assessment,
EPA
is
proposing
revisions
to
the
method
detection
limit
procedure
codified
at
40
CFR
part
136,
Appendix
B
and
is
seeking
comment
on
the
revisions
proposed
in
this
notice.
EPA
also
is
proposing
to
revise
the
definition
of
``
Detection
limit''
at
40
CFR
136.2
and
to
add
a
definition
of
the
``
Minimum
level
of
quantitation
(
ML)''
for
consistency
with
the
proposed
revisions
to
Appendix
B.

III.
Background
A.
Analytical
(
Test)
Methods
Used
for
CWA
Programs
Section
304(
h)
of
the
Clean
Water
Act
requires
that
the
EPA
Administrator
``
promulgate
guidelines
establishing
test
procedures
for
the
analysis
of
pollutants''
to
be
monitored
and
regulated
under
the
National
Pollutant
Discharge
Elimination
System
(
NPDES).
EPA
proposes
and
promulgates
test
methods
at
40
CFR
part
136
in
accordance
with
section
304(
h).
The
approved
test
methods
have
been
drawn
from
a
variety
of
sources,
including
methods
developed
by
commercial
vendors,
EPA
and
other
government
agencies,
as
well
as
methods
from
voluntary
consensus
standards
bodies
(
VCSBs),
such
as
the
American
Public
Health
Association
(
APHA),
the
Water
Environment
Federation
(
WEF),
and
the
American
Water
Works
Association
(
AWWA),
which
jointly
publish
Standard
Methods
for
the
Examination
of
Water
and
Wastewater;
the
Association
of
Official
Analytical
Chemists
(
AOAC­
International);
and
the
American
Society
for
Testing
and
Materials
(
ASTM
International).
Among
considerations
for
approval
of
a
test
method
at
40
CFR
part
136
are
the
demonstrated
performance
characteristics
of
precision,
bias,
and
sensitivity
(
i.
e.,
detection
and
quantitation).
EPA
generally
evaluates
each
of
these
characteristics
to
determine
if
the
test
method
will
yield
results
at
concentrations
of
concern
that
are
reliable
enough
to
meet
EPA
needs
for
permitting
and
compliance
monitoring
under
the
CWA.
Detection
and
quantitation
limits
have
been
among
the
most
controversial
of
these
characteristics,
particularly
among
members
of
the
regulated
community.

B.
Settlement
Agreement
On
June
8,
1999,
EPA
published
a
final
rule
adding
EPA
Method
1631,
Revision
B:
Mercury
in
Water
by
Oxidation,
Purge
and
Trap,
and
Cold
Vapor
Atomic
Fluorescence
Spectrometry
(
Method
1631B)
to
the
``
Guidelines
Establishing
Test
Procedures
for
the
Analysis
of
Pollutants''
under
section
304(
h)
of
the
Clean
Water
Act.
This
method
was
developed
specifically
to
measure
concentrations
of
mercury
at
low
(
i.
e.,
ambient
water
quality
criteria)
levels.
Following
promulgation,
the
Alliance
of
Automobile
Manufacturers,
the
Chemical
Manufacturers
Association,
and
the
Utility
Water
Act
Group
(``
Petitioners'')
and
the
American
Forest
and
Paper
Association
(``
Intervenor'')
filed
a
lawsuit
challenging
the
method.
(
Alliance
of
Automobile
Manufacturers,
et
al.
v.
EPA,
No.
99
 
1420
(
D.
C.
Cir.)).
The
challenge
addressed
specific
aspects
of
EPA
Method
1631
as
well
as
the
general
procedures
used
to
establish
the
method
detection
limit
(
MDL)
and
the
minimum
level
of
quantitation
(
ML)
specified
in
the
method.
On
October
19,
2000,
EPA
entered
into
a
settlement
agreement
with
the
Petitioners
and
Intervenor
(
the
``
settlement
agreement'').
The
settlement
agreement
included
six
clauses.
EPA
has
already
satisfied
the
requirements
of
clauses
1
through
5,
which
addressed
clarification
and
revision
of
specific
method
procedures
and
requirements.
This
proposal
partially
fulfills
the
requirements
of
clause
6
of
the
settlement
agreement,
which
addresses
procedures
for
determining
the
sensitivity
of
analytical
test
methods.
Clause
6
provides
for
EPA
to
assess
existing
Agency
and
alternative
procedures
for
determining
detection
and
quantitation
limits
under
the
Clean
Water
Act
and
to
sign
a
notice
for
publication
in
the
Federal
Register
on
or
before
February
28,
2003,
inviting
public
comment
on
the
assessment.
The
assessment
is
to
include,
at
a
minimum,
evaluation
of
the
``
Definition
and
Procedure
for
Determination
of
the
Method
Detection
Limit''
published
at
40
CFR
part
136,
Appendix
B
and
used
in
Method
1631,
and
evaluation
of
the
corresponding
``
minimum
level''
of
quantitation
procedures.
Clause
6
further
provides
for
EPA
to
submit
its
assessment
to
formal
peer
review
by
experts
in
the
field
of
analytical
chemistry
and
in
the
statistical
aspects
of
analytical
data
interpretation.
EPA
conducted
peer
review
of
its
assessment
in
August
2002.
A
summary
of
the
results
of
the
peer
review
is
provided
in
section
VI
of
this
proposal;
the
peer
reviewers'
comments
and
EPA's
responses
are
included
in
the
docket
for
this
proposal.
As
stipulated
in
the
settlement
agreement,
EPA
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provided
the
draft
Assessment
Document
to
the
Petitioners
and
Intervenor
for
concurrent
review
and
comment
in
August
2002.
Their
comments
are
also
included
in
the
docket
for
this
proposal.
Finally,
EPA
agreed
to
invite
public
comment
on
the
assessment
for
a
period
of
no
less
than
120
days
and
to
sign
a
notice
taking
final
action
on
the
assessment
on
or
before
September
30,
2004.
Elsewhere
in
today's
Federal
Register,
EPA
is
publishing
a
notice
of
availability
of
the
Assessment
Document,
titled
``
Technical
Support
Document
for
the
Assessment
of
Detection
and
Quantitation
Concepts,''
and
announcing
a
120­
day
comment
period
on
it.

C.
Detection,
Quantitation,
and
Current
Controversy
Generally
speaking,
a
detection
limit
is
the
lowest
concentration
or
amount
of
a
substance
that
allows
for
differentiation
between
a
sample
that
contains
the
substance
and
one
that
does
not.
A
quantitation
limit
is
the
lowest
concentration
or
amount
of
a
substance
that
can
be
measured
with
some
stated
level
of
confidence.
Establishing
such
detection
and
quantitation
limits
generally
involves
the
application
of
statistics
and
chemistry
expertise
and
judgement.
The
fact
that
scientific
judgement
is
involved
in
the
detection
and
quantitation
decision
is
evidenced
by
the
continuing
debate
on
this
subject;
the
number
of
different
terms
currently
in
use
by
different
organizations;
the
number
of
concepts
and
procedures
that
have
been
advanced
by
different
organizations
to
define
or
determine
the
detection
and
quantitation
capabilities
of
analytical
test
methods;
and
the
fact
that
there
is
no
general
consensus
among
various
government
agencies,
method
developers,
or
scientific
organizations
on
a
single
detection
and
quantitation
approach.
EPA
estimates
that
more
than
50
different
terms
have
been
used
in
published
analytical
test
methods
to
describe
detection
and
quantitation
capabilities
of
test
methods
and,
in
many
instances,
the
same
term
is
used
by
different
organizations
to
mean
different
things.
Nearly
all
of
the
approaches
advanced
to
date
fall
into
one
of
two
main
categories:
(
1)
Those
that
assume
measurement
error
is
constant
or
effectively
constant
in
the
low
concentration
range
and
are,
therefore,
based
on
the
error
observed
in
replicate
measurements
made
at
a
single
low
concentration,
and
(
2)
those
that
assume
measurement
error
varies
as
a
function
of
concentration
and
are,
therefore,
based
on
the
error
observed
in
replicate
measurements
gathered
in
the
region
of
detection
and
quantitation.
Examples
of
the
first
category
(
referred
to
as
the
``
single
concentration
approach''
or
``
constant
error
model'')
include
those
first
advanced
by
Lloyd
Currie
(
1968)
and
later
adopted
in
various
forms
by
the
American
Chemical
Society
(
ACS),
the
International
Organization
for
Standardization
(
also
known
as
``
ISO''),
the
International
Union
of
Pure
and
Applied
Chemistry
(
IUPAC),
and
EPA.
Examples
of
the
latter
category
(
the
``
variable
error
model'')
were
adopted
in
various
forms
by
the
U.
S.
Army
Toxic
and
Hazardous
Materials
Agency
(
USATHAMA,
now
the
U.
S.
Army
Environmental
Center,
or
USAEC)
and
ASTM
International.
The
two
categories
represent
two
somewhat
different
conceptual
approaches
to
the
problem
of
assessing
detection
and
quantitation
capabilities.
Both
approaches
require
estimates
of
measurement
variability
in
the
low
concentration
range,
but
the
philosophy
behind
the
first
category
is
based
on
direct
measurement
of
variability
at
a
fixed
concentration
in
the
concentration
region
most
relevant
to
the
problem.
The
philosophy
behind
the
second
category
is
based
on
the
concept
that
measurement
variability
throughout
the
low
end
of
the
measurement
range
is
relevant
to
the
problem
of
setting
detection
and
quantitation
limits.
The
methodology
used
in
implementing
procedures
in
the
second
category
involves
statistical
estimation
methods
that
allow
data
collected
throughout
the
low
end
of
the
range
to
contribute
to
estimation
of
measurement
variability
in
detection
and
quantitation
region.
There
are
also
differences
in
the
experimental
procedures
used
to
determine
detection
and
quantitation
limits.
Again,
these
tend
to
fall
into
two
categories.
The
first
category
of
singlelaboratory
detection
limits
uses
data
from
an
experiment
in
a
single
laboratory
to
estimate
detection
limits.
The
second
category
of
multi­
laboratory
detection
limits
uses
data
from
experiments
from
multiple
laboratories
to
estimate
detection
limits.
The
rationale
for
the
latter
proposal
is
that
actual
measurement
sensitivity
varies
among
laboratories,
regardless
of
the
approach
used
to
estimate
the
sensitivity
of
a
given
method.
The
Interlaboratory
Detection
Estimate
(
IDE)
and
the
Interlaboratory
Quantitation
Estimate
(
IQE)
adopted
by
ASTM
International
is
an
example
of
such
an
approach.
Although
EPA's
MDL
procedure
does
not
incorporate
specific
procedures
to
account
for
multiple
laboratory
variability,
EPA
nonetheless
has
accounted
for
this
variability
during
method
validation
as
described
in
Section
D.
1
below.

D.
Historical
Use
of
Detection
and
Quantitation
Limits
Under
the
Clean
Water
Act
The
procedure
for
estimating
the
MDL
was
originally
published
in
1981
by
staff
at
EPA's
environmental
research
laboratory
in
Cincinnati,
Ohio
(
Glaser,
et
al.,
1981).
The
MDL
is
based
on
the
constant
error
model
described
by
Currie
(
1968).
EPA
promulgated
the
procedure
for
determining
the
MDL
for
use
in
CWA
programs
on
October
26,
1984
(
49
FR
43234).
The
ML
was
originally
proposed
on
December
5,
1979
(
44
FR
69463),
in
footnotes
to
Table
2
of
EPA
Method
624
and
to
Tables
4
and
5
of
EPA
Method
625.
Between
1980
and
1984,
EPA
developed
Methods
1624
and
1625
and
included
the
ML
in
similar
tables
in
those
two
methods.
When
these
four
methods
were
promulgated
for
use
in
CWA
programs
on
October
26,
1984
(
49
FR
43234),
EPA
replaced
the
MLs
in
Methods
624
and
625
with
MDLs,
and
retained
the
MLs
in
Methods
1624
and
1625.
Unlike
the
MDL,
there
have
been
changes
to
the
definition
of
the
ML
over
the
years.
For
example,
the
term
``
recognizable
signal''
has
been
used
instead
of
``
recognizable
mass
spectra''
for
non­
GC/
MS
methods.
Since
1984,
the
MDL
and
ML
have
been
used
in
a
variety
of
ways
by
analytical
laboratories,
permitting
authorities,
and
regulatory
communities.
The
three
most
significant
uses
of
the
MDL
are
described
below,
along
with
some
concerns
with
those
uses.

1.
Method
Development
The
primary
purpose
of
the
MDL
and
ML
is
to
characterize
the
sensitivity
of
a
particular
test
method
for
a
particular
pollutant.
Information
about
method
sensitivity
is
critical
when
deciding
which
method
is
needed
to
accomplish
a
specific
measurement
objective.
The
MDLs
published
in
some
EPA
methods
have
been
criticized
because
they
are
based
on
the
performance
of
a
single
laboratory
that
may
not
reflect
the
capabilities
of
the
laboratory
community.
EPA
has
responded
to
this
criticism
in
recent
years
by
gathering
MDL
information
from
multiple
laboratories.
During
development
of
several
analytical
methods,
EPA's
Office
of
Science
and
Technology
addressed
the
issue
by
using
single
laboratory
studies
to
develop
an
initial
estimate
of
the
MDL
for
each
analyte
and
then
verified
these
MDLs
in
interlaboratory
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studies
or
in
additional
singlelaboratory
studies
at
other
facilities.
For
example,
when
EPA
initially
drafted
Method
1631
for
measurement
of
mercury,
EPA
estimated
the
MDL
to
be
0.05
ng/
L,
based
on
results
produced
by
a
contract
research
laboratory.
Additional
single­
laboratory
studies
suggested
that
the
MDL
should
be
raised
to
0.2
ng/
L
to
better
reflect
existing
capabilities
of
the
laboratory
community.
During
EPA's
interlaboratory
study
for
Method
1631,
twelve
participant
laboratories
were
asked
to
conduct
MDL
studies.
Each
laboratory
obtained
an
MDL
less
than
0.2
ng/
L,
the
value
published
in
the
promulgated
version
of
Method
1631.
The
ML
has
been
used
in
the
1600­
series
of
EPA
chemical
methods
promulgated
for
use
under
the
CWA
since
1984
as
an
additional
means
to
characterize
method
sensitivity,
establish
the
lower
end
of
the
calibration
range,
and
serve
as
a
quantitation
limit
in
those
methods.
Although
its
use
has
thus
far
been
limited
to
the
1600­
series
methods,
the
ML
concept
is
applicable
to
any
analytical
procedure
to
which
the
MDL
can
be
applied
under
the
CWA.

2.
Demonstrating
Laboratory
Performance
The
MDL
also
has
been
used
as
a
means
of
demonstrating
laboratory
capability
or
performance.
For
example,
a
laboratory
often
publishes
results
of
an
MDL
study
to
advertise
its
ability
to
detect
a
pollutant
at
a
low
level.
Similarly,
a
laboratory
client
or
a
certification
program
may
require
that
a
laboratory
demonstrate
its
ability
to
achieve
a
specified
MDL
using
a
particular
method.
EPA
also
has
used
MDLs
in
approved
EPA
CWA
methods
(
i.
e.,
promulgated
at
40
CFR
part
136)
to
provide
a
standard
for
allowing
increased
flexibility
and
encouraging
advances
in
technology.
Under
EPA's
CWA
Alternate
Test
Procedures
(
ATP)
program
and
in
EPA's
performance­
based
methods,
a
laboratory
is
permitted
to
modify
certain
aspects
of
approved
method
procedures
provided
that
it
is
able
to
achieve
an
MDL
that
is
less
than
or
equal
to
onethird
the
regulatory
compliance
limit
or
less
than
or
equal
to
the
MDL
specified
in
the
approved
method,
whichever
is
greater
(
see
section
9.0
of
EPA
Method
1631,
for
example).

3.
Use
of
the
MDL
and
ML
in
Clean
Water
Act
Programs
Both
the
MDL
and
ML
have
been
used
as
reporting
limits
for
a
variety
of
studies
and
monitoring
efforts
under
the
CWA.
For
example,
EPA
often
uses
the
MDL
as
a
reporting
threshold
in
surveys
designed
to
determine
levels
of
human
exposure
from
consumption
of
water
or
fish
under
the
CWA
in
order
to
characterize
health
risks
from
a
variety
of
pollutants.
In
recent
years,
EPA
has
used
the
ML
as
the
reporting
limit
in
setting
numeric
limits
for
effluent
guidelines
limitations.
EPA
recommended
in
a
1994
draft
guidance
document
that
the
ML
be
included
in
a
National
Pollutant
Discharge
Elimination
System
(
NPDES)
permit
as
a
footnote
to
the
water
quality­
based
effluent
limit
(
WQBEL)
when
the
WQBEL
is
below
either
the
MDL
or
ML
of
the
most
sensitive
method.
(
See
U.
S.
EPA
Draft
National
Guidance
for
the
Permitting,
Monitoring,
and
Enforcement
of
Water
Quality­
based
Effluent
Limitations
Set
Below
Analytical
Detection/
Quantitation
Levels,
1994.)
This
1994
draft
guidance
document
was
very
controversial
and
was
never
finalized.
Because
individual
States
are
responsible
for
implementation
and
enforcement
of
NPDES
permits,
use
of
the
MDL
and
ML
in
the
NPDES
program
varies
among
the
States.

4.
Concerns
Regarding
Use
of
the
MDL
Over
the
years,
a
number
of
concerns
have
been
raised
about
the
MDL
procedure.
Some
of
these
concerns
are
technical
in
nature
(
e.
g.,
selection
of
appropriate
spiking
levels
and
treatment
of
outliers),
while
others
focus
on
implementation
(
e.
g.,
use
of
the
MDL
as
a
regulatory
compliance
limit).
As
part
of
EPA's
assessment
of
detection
and
quantitation
limits,
the
Agency
identified
and
investigated
a
number
of
issues,
including
concerns
that
had
been
presented
to
the
Agency
by
a
variety
of
sources
(
e.
g.,
commercial
laboratories,
permittees,
State
laboratory
and
permitting
authorities,
EPA
and
other
Federal
laboratories,
and
others).
Section
IV.
D
of
this
proposal
highlights
the
most
significant
issues
addressed
during
the
recent
assessment.
A
comprehensive
discussion
of
these
issues
is
provided
in
the
Assessment
Document
that
is
available
in
the
docket
supporting
today's
proposed
rule
and
noticed
elsewhere
in
today's
Federal
Register
for
public
comment.

IV.
EPA's
Assessment
of
Detection
and
Quantitation
Concepts
EPA
first
began
a
comprehensive
assessment
of
detection
and
quantitation
limits
in
the
mid­
1990s
as
concerns
about
the
increased
use
of
water
quality­
based
permitting
began
to
push
permit
limits
for
many
pollutants
below
the
measurement
capabilities
of
some
laboratories
for
a
number
of
environmental
chemistry
methods.
One
of
the
key
areas
of
concern
centered
on
the
nature
of
measurement
error
in
the
region
of
detection
and
quantitation.
Because
EPA
was
not
aware
of
studies
that
included
replicate
testing
across
or
within
the
vicinity
of
this
region,
EPA
focused
its
early
efforts
on
developing
such
data,
first
with
a
single­
laboratory
study
of
measurement
error
using
inductively
coupled
plasma­
mass
spectrometry
(
ICP­
MS)
techniques,
and
later
with
a
similar
single­
laboratory
study
of
measurement
error
using
10
different
analytical
techniques
commonly
used
in
Clean
Water
Act
monitoring
programs.
The
October
2000
settlement
agreement
described
in
section
III.
B.
of
this
preamble
committed
EPA
to
a
fixed
timetable
and
established
specific
milestones
for
completing
its
assessment.
The
general
approach
used
in
the
Agency's
assessment
of
detection
and
quantitation
concepts
and
procedures
is
summarized
below.
Additional
details
concerning
the
assessment
are
presented
in
the
Assessment
Document
that
is
available
in
the
public
docket
supporting
this
proposed
rule.
EPA
is
also
providing
an
opportunity
for
public
review
and
comment
on
this
assessment
and
the
Assessment
Document
in
a
separate
notice
in
today's
Federal
Register
(
see
Notice
of
Document
Availability
and
Public
Comment
Period
on
the
Technical
Support
Document
for
the
Assessment
of
Detection
and
Quantitation
Concepts).

A.
Study
Plan
In
December
of
2001,
EPA
produced
a
draft
Plan
for
the
Assessment
of
Detection
and
Quantitation
Limits
Under
Section
304(
h)
of
the
Clean
Water
Act.
The
December
2001
plan
described
roles
and
responsibilities
for
implementing
the
plan,
provided
a
background
discussion
of
detection
and
quantitation
limit
concepts,
and
outlined
a
series
of
events
necessary
to
support
EPA's
assessment
of
detection
and
quantitation
concepts
and
procedures
as
required
to
comply
with
the
terms
and
schedules
set
forth
in
Clause
6
of
the
settlement
agreement.
The
draft
plan
was
circulated
for
review
by
EPA
staff,
the
Petitioners
and
Intervenor,
and
external
peer
reviewers.
The
external
peer
review
was
performed
in
accordance
with
EPA's
Science
Policy
Council
Handbook
 
Peer
Review,
2nd
Edition
(
EPA
100
 
B
 
00
 
001,
December
2001;
the
``
Peer­
review
Handbook'').
EPA
evaluated
the
comments
and
recommendations
provided
by
reviewers
and,
where
appropriate,
integrated
these
comments
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into
a
revised
version
of
the
Plan
for
the
Assessment
of
Detection
and
Quantitation
Limits
Under
Section
304(
h)
of
the
Clean
Water
Act
(
EPA
821
 
R
 
02
 
010,
April,
2002;
the
``
study
plan'').
The
study
plan
is
included
in
the
docket
for
this
proposal,
along
with
the
peer
review
comments
and
the
Agency's
response
to
them..

B.
Information
and
Data
used
in
the
Assessment
In
1997
and
1998,
EPA
searched
the
published
literature
to
identify
documents
that
discussed
detection
and
quantitation
concepts
and
procedures.
EPA
conducted
a
follow­
up
search
in
2001.
The
principal
goal
of
these
efforts
was
to
identify
concepts,
procedures,
and
issues
that
should
be
considered
by
EPA
during
its
assessment.
EPA
identified
more
than
100
documents
describing
detection
and
quantitation
concepts
and
issues
and
has
included
a
list
of
these
documents
in
the
docket
supporting
this
proposed
rule.
Additional
information
concerning
the
literature
search
is
presented
and
discussed
in
the
Assessment
Document.
EPA
initially
hoped
to
identify
a
large
body
of
data
containing
a
sufficient
number
of
results
that
were
generated
at,
below,
and
above
the
region
of
interest
(
i.
e.,
at
concentration
levels
targeting
limits
of
detection
and
quantitation).
EPA
determined,
however,
that
few
such
data
sets
exist.
EPA
identified
six
useful
data
sets
for
fully
evaluating
measurement
variability
in
the
range
of
analytical
detection
and
quantitation.
These
included
three
data
sets
generated
by
EPA
expressly
for
the
purpose
of
characterizing
measurement
variability
in
the
region
of
interest
and
three
data
sets
suggested
by
the
Petitioners
and
Intervenor.
Although
the
Petitioners
and
Intervenor
suggested
other
data
sets,
EPA
found
that
these
data
sets
either
did
not
include
a
sufficient
number
of
data
results
that
were
at,
below,
and
above
the
region
of
detection
and
quantitation
to
yield
information
for
the
assessment
or
that
the
data
included
in
the
data
sets
were
of
questionable
validity.
These
data,
and
EPA's
decisions
regarding
the
data,
are
discussed
in
the
Assessment
Document.
As
noted
above,
three
of
these
studies
were
conducted
by
EPA
for
the
purpose
of
evaluating
the
relationship
between
measurement
variation
and
concentration.
In
these
studies,
replicate
measurements
from
each
combination
of
analyte
and
measurement
technique
(
i.
e.,
analytical
method)
were
produced
by
a
single
laboratory
over
a
wide
range
and
large
number
of
concentrations.
A
fourth
data
set
was
developed
as
part
of
a
study
conducted
by
the
American
Automobile
Manufacturers
Association
(
AAMA)
for
the
purpose
of
estimating
a
quantitation
value
based
on
a
concept
called
the
alternative
minimum
level
that
had
been
described
in
the
literature
(
Gibbons
et
al.,
1997).
In
that
study,
replicate
samples
were
measured
at
a
limited
number
of
concentrations
by
multiple
laboratories.
The
final
two
data
sets
were
jointly
gathered
by
EPA
and
the
Electric
Power
Research
Institute
(
EPRI)
to
support
interlaboratory
validation
of
EPA
Methods
1631
and
1638.
Additional
details
concerning
each
of
these
studies
are
provided
in
the
Assessment
Document
available
in
the
docket
supporting
this
proposed
rule.
Data
from
these
studies
also
are
available
in
the
docket.

C.
Concepts
and
Procedures
Included
in
the
Assessment
As
mentioned
earlier
in
this
document,
EPA
identified
numerous
terms
that
have
been
used
to
describe
the
sensitivity
of
a
particular
method
or
instrument.
Examples
of
these
terms
are
analytical
detection
limit,
lower
limit
of
detection,
limit
of
sensitivity,
minimum
detectable
quantity,
system
detection
limit,
and
approximate
detection
limit.
For
its
assessment,
EPA
considered
detection
and
quantitation
terms,
concepts,
or
procedures
advanced
in
the
published
literature
and
by
various
EPA
offices,
the
American
Chemical
Society
(
ACS),
the
International
Union
of
Pure
and
Applied
Chemistry
(
IUPAC),
the
International
Organization
for
Standardization
(
ISO),
ASTM
International,
industry
groups,
and
others.
EPA
found
that
most
of
the
terms
or
concepts
considered
have
no
corresponding
definition
or
procedure
for
calculating
a
value,
and
it
may
be
that
these
terms
reflect
the
method
developer's
estimate
of
the
lowest
concentration
of
a
substance
that
a
test
method
is
capable
of
measuring.
EPA
did
not
evaluate
any
such
terms
in
the
assessment.
EPA
also
did
not
consider
terms
that
do
not
reflect
the
entire
measurement
process
(
such
as
the
``
Instrument
Detection
Limit''),
concepts
that
are
uniquely
designed
for
a
single
program
(
such
as
the
``
Contract
Required
Detection
Limit''
used
in
the
Superfund
Contract
Laboratory
Program),
or
concepts
no
longer
advanced
by
the
originating
organization
(
such
as
the
``
Compliance
Monitoring
Detection
Limit''
and
the
``
Alternative
Minimum
Level'').
After
eliminating
terms
and
concepts
for
the
reasons
described
above,
EPA
focused
its
assessment
on
four
sets
of
concepts
that
are
widely
referenced
and
generally
reflect
the
diversity
of
concepts
advanced
to
date.
These
include
(
1)
The
EPA
MDL
and
ML
used
under
CWA
programs,
(
2)
the
Interlaboratory
Detection
Estimate
(
IDE)
and
Interlaboratory
Quantitation
Estimate
(
IQE)
adopted
by
ASTM
International,
(
3)
the
Limit
of
Detection
(
LOD)
and
Limit
of
Quantitation
(
LOQ)
adopted
by
the
American
Chemical
Society
(
ACS),
and
(
4)
the
Critical
Value
(
CRV),
Minimum
Detectable
Value
(
MDV)
and
Limit
of
Quantification
(
LOQ)
adopted
by
the
International
Union
of
Pure
and
Applied
Chemistry
(
IUPAC)
and
the
International
Organization
for
Standardization
(
ISO).
Although
the
ACS,
IUPAC
and
ISO
concepts
are
functionally
similar
to
EPA's
MDL
and
ML,
these
organizations
have
not
developed
detailed
procedures
for
calculating
detection
and
quantitation
values.
Only
the
EPA
and
ASTM
concepts
are
supported
by
detailed
procedures
for
calculating
detection
and
quantitation
values.
Without
such
procedural
details,
the
ACS,
IUPAC
and
ISO
concepts
are
unlikely
to
be
useful
for
establishing
detection
and
quantitation
limits
in
analytical
methods
for
use
in
CWA
programs.
Therefore,
the
discussion
below
addresses
the
EPA
and
ASTM
concepts
only.
Results
of
EPA's
evaluation
of
the
additional
concepts
are
discussed
in
detail
in
the
Assessment
Document
included
in
the
docket
supporting
this
proposed
rule.

1.
Method
Detection
Limit
(
MDL)
and
Minimum
Level
(
ML)
of
Quantitation
As
discussed
in
section
III.
D
of
this
document,
the
MDL
is
based
on
the
constant
error
model
proposed
by
Currie
in
1968
and
was
initially
promulgated
in
1984
for
use
in
CWA
programs.
The
MDL
and
ML
are
supported
by
a
procedure
that
involves
the
analysis
of
at
least
seven
replicate
samples
containing
the
target
analyte(
s)
at
an
estimate
of
the
detection
limit.
Determination
of
the
MDL
is
based
on
multiplication
of
the
standard
deviation
among
the
replicate
measurements
by
the
99th
percentile
of
a
t­
distribution
with
n­
1
degrees
of
freedom.
The
ML
is
also
based
on
the
constant
error
model
proposed
by
Currie
in
1968.
The
ML
is
derived
by
multiplying
the
standard
deviation
of
the
replicate
measurements
by
10.
The
primary
differences
between
the
MDL,
ML,
and
detection
and
quantitation
limit
concepts
first
proposed
by
Currie
are
that
(
1)
The
MDL
and
ML
are
supported
by
detailed
procedures
for
implementing
the
concepts,
and
(
2)
the
EPA
CWA
procedures
extend
Currie's
proposed
replicate
measurements
of
a
blank
with
replicate
measurements
of
reagent
water
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(
or
other
reference
matrix)
to
which
a
small
amount
of
the
analyte
is
added.
This
latter
difference
results
from
the
fact
that
the
concepts
developed
by
Currie
assume
that
measurements
on
blank
samples
will
produce
a
signal
that
can
be
used
to
estimate
measurement
variability.
This
is
the
case
with
radiochemistry
analyses,
where
there
is
usually
some
background
radiation
that
produces
a
response
in
the
analysis
of
a
blank
sample.
For
many
other
types
of
environmental
analyses,
the
analysis
of
a
blank
sample
produces
no
instrumental
response.
Thus,
the
EPA
CWA
MDL
procedure
involves
adding
the
analyte
to
a
reference
matrix
(
e.
g.,
a
blank
sample)
at
low
concentrations
to
ensure
that
a
response
is
produced.

2.
Interlaboratory
Detection
Estimate
(
IDE)
and
Interlaboratory
Quantitation
Estimate
(
IQE)
The
IDE
was
approved
by
ASTM
International's
Committee
D
19
for
Water
in
1997,
as
ASTM
Designation
6091
 
97:
Standard
Practice
for
99%/
95%
Interlabortory
Detection
Estimate
(
IDE)
for
Analytical
Methods
with
Negligible
Calibration
Error.
Subsequently,
members
of
ASTM
Committee
D
19
developed
the
interlaboratory
quantitation
estimate
(
IQE)
that
was
approved
in
2000
as
ASTM
Designation
D
6512
 
00:
Standard
Practice
for
Interlaboratory
Quantitation
Estimate.
The
IDE
and
IQE
concepts
are
based
on
the
variable
error
model
and
include
procedures
that
require
that
data
gathered
in
a
formal
study
of
a
method
be
used
to
select
from
one
of
four
possible
models
of
the
interlaboratory
error
and
concentration.
The
possible
models
include:
the
``
constant
model,''
applicable
to
both
the
IDE
and
IQE,
in
which
the
interlaboratory
standard
deviation
does
not
change
with
concentration;
the
``
straight­
line
model,''
applicable
to
both
the
IDE
and
IQE,
in
which
the
interlaboratory
standard
deviation
is
a
linear
function
of
concentration;
the
``
exponential
model''
applicable
to
the
IDE,
in
which
the
interlaboratory
standard
deviation
is
an
exponential
function
of
concentration;
and
the
``
hybrid
model''
applicable
to
the
IQE,
in
which
the
interlaboratory
standard
deviation
has
both
additive
(
constant)
and
multiplicative
(
linear)
components
that
follow
the
model
of
Rocke
and
Lorenzato
(
1995).
Such
studies
involve
samples
representing
at
least
five
different
concentration
levels
and
analyzed
in
a
minimum
of
six
(
required)
to
ten
(
recommended)
laboratories.
The
ASTM
procedures
are
also
designed
to
take
into
account
all
possible
sources
of
variability,
including
interlaboratory
variability,
when
estimating
detection
and
quantitation
limits.
As
a
result,
the
IDE
and
IQE
generally
produce
higher
limits
than
are
produced
using
other
procedures.

D.
Issues
Considered
During
the
Assessment
In
performing
the
assessment,
EPA
identified
a
number
of
statistical
and
analytical
chemistry
issues
that
should
be
considered
when
evaluating
detection
and
quantitation
limit
concepts
and
procedures
in
general,
and
in
the
specific
context
of
Clean
Water
Act
applications.
The
issues
considered
include
six
specific
issues
raised
by
the
Petitioners
and
Intervenor,
as
well
as
issues
identified
by
EPA
staff,
peer
reviewers,
and
others.
The
six
issues
raised
by
the
Petitioners
are:
Criteria
for
selection
and
appropriate
use
of
statistical
models;
methodology
for
parameter
estimation;
statistical
tolerance
and
prediction;
criteria
for
design
of
detection
and
quantification
studies,
including
selection
of
concentration
levels
(``
spiking
levels'');
interlaboratory
variability;
and
incorporation
of
elements
of
probability
design.
Some
of
the
significant
additional
issues
considered
by
EPA
in
its
assessment
include:
Matrix
effects;
minimization
of
false
positives
and
false
negatives;
cost
and
ease
of
implementation;
and
how
well
detection
and
quantitation
limits
published
in
methods
reflect
individual
laboratory
capability.
These
and
other
issues
considered
by
EPA
are
identified
and
discussed
in
Chapter
3
of
the
Assessment
Document.

E.
Evaluation
Criteria
After
identifying
and
considering
the
issues,
EPA
developed
six
evaluation
criteria
that
reflect
EPA's
views
concerning
the
issues.
These
six
criteria
formed
the
primary
basis
for
evaluating
the
ability
of
each
detection
and
quantitation
limit
approach
identified
in
section
III.
C.
above
to
meet
EPA
needs
under
the
Clean
Water
Act.
A
complete
discussion
of
these
criteria
and
EPA's
assessment
of
each
approach
against
these
criteria
is
provided
in
the
Assessment
Document
that
is
available
in
the
docket
supporting
this
proposed
rule.
The
six
criteria
are
summarized
below.
Criterion
1:
The
detection
and
quantitation
limit
approaches
should
be
scientifically
valid.
In
evaluating
this
criterion,
EPA
considered
the
following
factors:
(
1)
Whether
the
concept
can
be
(
and
has
been)
tested;
(
2)
whether
the
concept
has
been
subjected
to
peer
review
and
publication;
(
3)
whether
the
error
rate
associated
with
the
concept
or
methodology
is
either
known
or
can
be
estimated;
(
4)
whether
standards
exist
and
can
be
maintained
to
control
the
concept's
operation
(
i.
e.,
it
is
supported
by
well­
defined
procedures
for
use);
and
(
5)
whether
the
concept
has
attracted
(
i.
e.,
achieved)
widespread
acceptance
within
a
relevant
scientific
community.
EPA
believes
that
these
considerations
are
helpful
for
demonstrating
the
scientific
validity
of
a
detection
or
quantitation
concept.
Criterion
2:
The
approach
should
address
demonstrated
expectations
of
laboratory
and
method
performance,
including
routine
variability.
EPA
believes
that
the
detection
and
quantitation
limit
procedures
should
be
capable
of
providing
a
realistic
expectation
of
laboratory
performance.
In
evaluating
different
approaches
against
this
criterion,
EPA
considered
the
sources
of
variability
captured
by
the
procedure
and
the
degree
to
which
the
statistics
that
underlie
the
procedure
realistically
reflect
these
sources.
Criterion
3:
The
approach
should
be
supported
by
a
practical
and
affordable
procedure
that
a
single
laboratory
can
use
to
evaluate
method
performance.
Ideally,
any
required
procedure
for
calculating
analytical
method
sensitivity
should
be
simple,
complete,
and
costeffective
to
implement.
The
laboratories
that
can
be
expected
to
use
detection
and
quantitation
procedures
will
range
from
large
laboratories
and
laboratory
chains
with
a
wide
range
of
technical
capability
to
small
laboratories
operated
by
one
or
a
few
people
with
a
limited
set
of
statistical
or
analytical
skills.
If
a
procedure
is
complicated,
it
will
be,
generally,
more
error
prone
in
its
use.
Similarly,
if
a
procedure
requires
investment
of
extensive
resources
that
cannot
be
billed
to
a
client,
laboratories
will
have
a
disincentive
to
use
the
procedure.
Therefore,
if
EPA
wishes
to
encourage
the
development
and
use
of
innovative
techniques
that
improve
measurement
performance
or
lower
measurement
cost,
the
Agency
should
consider
practicality
and
affordability
as
significant,
if
not
co­
equal,
considerations
to
scientific
validity.
Criterion
4:
The
detection
level
approach
should
identify
the
signal
or
estimated
concentration
at
which
there
is
99%
confidence
that
the
substance
is
actually
present
when
the
analytical
method
is
performed
by
experienced
staff
in
a
well­
operated
laboratory.
Any
approach
to
developing
detection
limits
should
be
capable
of
providing
regulators,
the
regulated
community,
and
data
users
with
confidence
that
a
pollutant
reported
as
being
present
really
is
present.
Historically,
nearly
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every
detection
limit
approach
has
set
the
criterion
for
detection
at
99
percent
confidence
(
i.
e.,
the
lowest
level
at
which
a
pollutant
will
be
detected
with
a
probability
of
99
percent).
This
criterion
results
in
the
probability
of
a
false
positive;
i.
e.,
that
a
pollutant
will
be
stated
as
being
present
when
it
is
not
really
present
(
a
Type
I
error),
of
one
percent.
Criterion
5:
The
quantitation
limit
approach
should
identify
the
concentration
that
gives
a
recognizable
signal
that
is
consistent
with
the
capabilities
of
the
method
when
a
method
is
performed
by
experienced
staff
in
well­
operated
laboratories.
Measurement
capabilities
among
laboratories
vary
depending
on
a
number
of
factors,
including,
but
not
limited
to,
instrumentation,
training,
and
experience.
Similarly,
measurement
capabilities
among
different
analytical
methods
vary
depending
on
a
number
of
factors,
including
the
techniques
and
instrumentation
employed
and
the
clarity
of
the
method
itself.
Historical
approaches
to
recognizing
laboratory
capabilities
in
establishing
detection
and
quantitation
limits
have
varied
between
two
extremes
of
establishing
the
limit
in
a
state­
of­
the­
art
research
laboratory
to
reflect
the
lowest
possible
limit
that
can
be
achieved,
and
establishing
the
limit
based
on
statistical
prediction
intervals
calculated
from
a
large
number
of
laboratories
with
varying
levels
of
experience,
instrumentation
and
competence.
Generally,
use
of
the
former
has
been
employed
to
serve
as
a
goal
or
performance
standard
to
be
met
by
other
laboratories,
whereas
use
of
the
latter
treats
the
limit,
not
as
a
performance
standard
that
needs
to
be
met
by
each
laboratory,
but
rather
as
a
characterization
of
the
future
performance
of
the
entire
universe
of
laboratory
capabilities
at
the
time
of
method
development.
Rather
than
using
one
of
these
two
extremes,
EPA
prefers
to
establish
a
quantitation
limit
at
a
concentration
that
is
achievable
with
a
defined
level
of
confidence
in
welloperated
laboratories.
Criterion
6:
Detection
and
quantitation
approach
should
be
applicable
to
the
variety
of
decisions
made
under
the
Clean
Water
Act,
and
should
support
State
and
local
obligations
to
implement
measurement
requirements
that
are
at
least
as
stringent
as
those
set
by
the
Federal
Government.
The
Clean
Water
Act
requires
EPA
to
conduct,
implement,
and
oversee
a
variety
of
data
gathering
programs.
These
programs
include,
but
are
not
limited
to,
surveys
to
monitor
changes
in
ambient
water
quality,
screening
studies
to
identify
pollutants
of
concern,
data
gathering
to
support
effluent
guidelines,
environmental
assessments
to
establish
water
quality
standards,
and
studies
to
evaluate
human
health
and
environmental
risks
under
the
Clean
Water
Act.
In
addition,
EPA
should
be
able
to
apply
detection
and
quantitation
limits
to
permitting,
quality
control
in
analytical
laboratories,
method
promulgation,
and
other
uses
of
the
40
CFR
part
136
methods.

V.
EPA's
Findings
and
Conclusions
As
noted
previously,
EPA
considered
four
sets
of
detection
and
quantitation
limit
approaches
advanced
by
EPA,
ASTM
International,
ACS,
and
both
ISO
and
IUPAC.
Each
approach
was
assessed
against
the
suite
of
criteria
described
above
for
use
under
the
Clean
Water
Act.
The
EPA
approaches
(
i.
e.,
the
MDL
and
ML)
and
the
ASTM
International
approaches
(
i.
e.,
the
IDE
and
IQE)
are
supported
by
clearly
defined
procedures
for
implementing
the
concepts.
Neither
the
ACS
nor
the
ISO/
IUPAC
approaches
are
supported
by
detailed
procedures
for
implementation;
this
lack
of
supporting
procedures
was
reflected
in
the
outcome
of
EPA's
overall
assessment.
Briefly,
EPA
found
that
(
1)
no
single
pair
of
detection
and
quantitation
limit
concepts
perfectly
meets
EPA's
criteria
for
use
under
the
Clean
Water
Act,
(
2)
the
MDL
and
ML
most
closely
meet
EPA's
criteria,
and
(
3)
minor
revisions
and
clarifications
to
the
MDL
and
ML
would
allow
both
concepts
to
fully
meet
the
Agency's
needs
under
the
CWA.
Details
of
these
revisions
and
clarifications
are
described
in
section
VII
of
this
proposed
rule.
EPA
also
found
that,
although
the
IDE
and
IQE
procedures
may
be
acceptable
for
establishing
detection
and
quantitation
values
derived
from
interlaboratory
validation
studies,
the
complexity
and
subjectivity
of
the
procedures,
along
with
their
inability
to
address
individual
laboratory
performance,
make
them
unsuitable
as
the
primary
means
of
establishing
sensitivity
under
the
Clean
Water
Act.
However,
EPA
believes
that
the
IDE
and
IQE
can
be
used
to
establish
sensitivity
under
certain
conditions.
EPA
would
be
willing
to
consider
and
approve
under
40
CFR
part
136,
new
test
methods
that
include
the
IDE
and
IQE.
Details
of
EPA's
findings
are
provided
in
the
Assessment
Document
that
is
available
in
the
docket
supporting
this
proposed
rule.
VI.
Peer
Review
of
EPA's
Assessment
In
August
2002,
EPA
conducted
a
peer
review
of
its
assessment
as
presented
in
a
draft
Technical
Support
Document
(
draft
Assessment
Document).
The
peer
review
was
performed
in
accordance
with
EPA's
peer
review
policies,
which
are
described
in
the
Science
Policy
Council
Handbook
(
EPA
100
 
B
 
00
 
001),
and
performed
by
two
experts
in
the
field
of
analytical
chemistry
and
two
experts
in
the
statistical
aspects
of
analytical
data
interpretation.
Reviewers
were
provided
with
a
draft
copy
of
EPA's
Assessment
Document,
copies
of
all
data
evaluated
in
the
assessment,
statistical
programs
used
to
analyze
the
data,
and
copies
of
the
detection
and
quantitation
approaches
evaluated.
In
the
charge
to
the
peer
reviewers,
EPA
requested
a
written
evaluation
of
whether
the
assessment
approach
described
by
EPA
is
valid
and
of
the
conceptual
soundness
of
the
assessment.
Reviewers
also
were
asked
to
consider
and
address
eight
specific
questions
pertaining
to
the
adequacy
of
the
concepts
and
procedures,
the
issues
considered,
the
evaluation
criteria
developed
by
EPA,
EPA's
assessment
and
conclusions,
the
data
used
to
perform
the
assessment,
suggested
improvements
to
the
procedures
discussed,
and
EPA's
consideration
of
interlaboratory
vs.
intralaboratory
issues.
A
copy
of
all
materials
associated
with
the
peer
review,
including
the
peer
review
charge,
the
materials
provided
to
the
peer
reviewers
for
review,
complete
copies
of
the
peer
reviewers'
comments,
and
detailed
EPA
responses
to
each
of
the
comments
is
provided
in
the
docket
supporting
this
proposed
rule.
The
comments
from
the
peer
reviewers
were
generally
supportive
of
EPA's
assessment
and
its
presentation
of
the
assessment
in
the
draft
Assessment
Document.
The
peer
reviewers
stated
that
EPA's
assessment
of
detection
and
quantitation
concepts
appears
valid
based
on
the
evaluation
criteria
and
is
consistent
with
the
Data
Quality
Act
and
EPA's
Quality
System.
The
peer
reviewers
stated
further
that
the
detection
and
quantitation
concepts
and
procedures
considered,
the
issues
addressed,
and
the
evaluation
criteria
developed
based
on
those
issues
are
sufficiently
complete
and
adequate.
Although
two
of
the
four
peer
reviewers
believe
that
the
use
of
interlaboratory
measurements
is
important
for
a
general
understanding
of
the
laboratory
communities'
capabilities,
they
also
believe
that
the
MDL
and
ML
are
more
appropriate
to
address
the
issues
that
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Proposed
Rules
EPA
must
consider
in
support
of
a
permittee's
CWA
requirements.
These
commenters
concluded
that
EPA's
approach
between
inter­
and
intralaboratory
studies
is
balanced
and
reasonable.
Overall,
the
peer
reviewers
supported
the
continued
use
of
the
MDL
and
ML
procedures,
almost
to
the
exclusion
of
the
other
approaches.
The
most
notable
exception
was
a
suggestion
that
EPA
consider
abandoning
the
``
traditional''
concept
of
a
quantitation
limit,
such
as
the
ML,
and
instead
consider
that
any
measured
result
reported
with
an
associated
estimate
of
measurement
precision
is
a
quantifiable
value.
Reviewers
stated,
however,
that
use
of
the
ML
is
practical
if
EPA
desires
to
establish
a
quantitation
limit.
Although
the
peer
reviewers
were
generally
supportive
of
the
assessment
and
EPA's
current
approach
to
detection
and
quantitation
under
the
CWA,
they
had
some
recommendations
for
improvement
to
the
Agency's
assessment
and
to
the
MDL
procedure.
The
reviewers
suggested
that
EPA
consider
the
following:
(
1)
Providing
additional
references;
(
2)
expanding
the
discussion
of
outliers;
(
3)
establishing
a
repository
of
reference
materials
that
demonstrate
the
ability
to
handle
interferences
and
low
level
detection;
(
4)
making
minor
modifications
to
Evaluation
Criterion
4
(
i.
e.,
edit
to
reflect
equivalence
to
an
implementation
of
Currie's
critical
level);
(
5)
clarifying
the
MDL
confidence
interval
calculations
discussed
in
Chapter
5
of
the
Assessment
Document;
and
(
6)
enhancing
the
focus
on
the
impact
of
operational
procedures
(
quality
control)
in
method
performance.
The
Assessment
Document
available
in
the
docket
supporting
today
proposed
rule
addresses
each
of
these
suggestions.
The
peer
reviewers
also
suggested
the
following
improvements
to
the
MDL
procedure:
(
1)
Provide
clarification
to
indicate
that
blank
samples
can
be
used
to
estimate
the
MDL
if
those
blanks
generate
a
signal;
(
2)
revise
the
language
in
Step
1
of
the
MDL
procedure
to
address
certain
common
misunderstandings
(
e.
g.,
strengthen
the
discussion
of
the
selection
of
the
spiking
level
used
for
the
MDL
study);
and
(
3)
specify
that
the
spike
level
used
to
establish
the
MDL
should
not
be
more
than
a
factor
of
three
times
greater
than
the
calculated
MDL.
The
first
two
suggestions
from
the
peer
reviewers
regarding
improvements
to
the
MDL
procedure,
have
been
included
in
the
proposed
revision
to
the
MDL
procedure.
Although
EPA
agrees
with
the
theoretical
arguments
related
to
the
last
suggestion
regarding
the
spike
level,
EPA
already
tested
this
suggestion
in
one
of
its
studies
of
detection
and
quantitation
concepts
and
found
that
it
could
create
laboratory
burdens
that
far
exceed
the
benefits.
Specifically,
EPA
required
a
spike­
to­
MDL
ratio
of
three
in
its
multi­
technique
variability
studies
(
the
``
Episode
6000
studies''),
which
are
described
in
the
Assessment
Document
supporting
this
rule.
Two
laboratories
reported
that
a
large
number
of
iterations
would
be
required
(
particularly
in
multiple­
analyte
methods)
in
order
to
achieved
a
spiketo
MDL
ratio
of
three,
and
would
result
in
increased
laboratory
burden
and
cost.
Therefore,
this
suggestion
is
not
incorporated
into
the
revised
MDL
procedure
in
this
proposed
rule.
Based
on
peer
review
comments
and
comments
received
over
the
years
from
the
laboratory
community,
the
Petitioners,
and
other
stakeholders,
EPA
is
proposing
revisions
to
the
MDL
procedure
(
see
section
VII
below).

VII.
Proposed
Revisions
to
the
MDL
and
ML
This
proposal
would
revise
the
definition
of
detection
limit
for
use
under
the
CWA.
It
also
would
revise
certain
aspects
of
the
existing
procedure
for
determining
the
Method
Detection
Limit
(
MDL)
in
40
CFR
part
136,
Appendix
B
(
Definition
and
Procedure
for
the
Determination
of
the
Method
Detection
Limit)
and
modify
the
discussion
to
clarify
implementation
of
the
procedure.
It
also
requests
comment
on
whether
to
add
a
stand­
alone
definition
of
quantitation
limit
and
procedure
for
determining
the
Minimum
Level
of
Quantitation
(
ML)
in
Appendix
B.
This
proposal
incorporates
the
results
of
EPA's
recent
assessment
of
detection
and
quantitation
concepts
and
procedures
discussed
throughout
this
preamble
and
in
the
Assessment
Document,
and
address
various
stakeholder
comments
received
by
EPA
since
the
1984
promulgation
of
the
MDL
(
49
FR
43234,
October
26,
1984).
The
following
discussion
is
divided
into
five
sections:
(
1)
Revisions
to
the
definition
of
the
detection
limit
are
discussed
in
section
VII.
A;
(
2)
technical
revisions
to
the
MDL
procedure
are
discussed
in
section
VII.
B;
(
3)
clarifications
and
other
minor
editorial
changes
to
the
MDL
procedure
are
discussed
in
section
VII.
C;
(
4)
the
addition
of
a
definition
of
quantitation
limit
and
the
addition
of
a
procedure
to
calculate
the
ML
are
discussed
in
section
VII.
D;
(
5)
section
VII.
E
discusses
EPA's
continued
acceptance
of
analytical
methods
from
organizations
that
do
not
necessarily
use
EPA's
MDL
and
ML
procedures.

A.
Definition
of
the
Detection
Limit
Section
136.2(
f)
currently
defines
the
term
``
detection
limit''
to
mean
``
the
minimum
concentration
of
an
analyte
(
substance)
that
can
be
measured
and
reported
with
a
99%
confidence
that
the
analyte
concentration
is
greater
than
zero
as
determined
by
the
procedure
set
forth
at
appendix
B
of
this
part.''
EPA
is
proposing
to
revise
§
136.2(
f)
to
explicitly
equate
the
term
``
detection
limit''
with
the
``
method
detection
limit''
and
to
reflect
the
proposed
revisions
to
the
MDL
procedure
at
Appendix
B
as
follows:
``
Detection
limit
means
the
method
detection
limit
(
MDL),
as
determined
by
the
procedure
set
forth
at
Appendix
B
of
this
part.
The
MDL
is
an
estimate
of
the
measured
concentration
at
which
there
is
99%
confidence
that
a
given
analyte
is
present
in
a
given
sample
matrix.''
EPA
also
is
proposing
to
revise
the
definition
of
the
Method
Detection
Limit
included
in
Appendix
B
as
follows:
``
The
MDL
is
an
estimate
of
the
measured
concentration
at
which
there
is
99%
confidence
that
a
given
analyte
is
present
in
a
given
sample
matrix.''
The
MDL
is
the
concentration
at
which
a
decision
is
made
regarding
whether
an
analyte
is
detected
by
a
given
analytical
method.
The
MDL
is
calculated
from
replicate
analyses
of
a
matrix
containing
the
analyte
and
is
functionally
analogous
to
the
``
critical
value''
described
by
Currie
(
1968,
1995)
and
the
Limit
of
Detection
described
by
the
American
Chemical
Society
(
Keith
et
al.,
1980,
McDougal
et
al.,
1983).
EPA
also
is
requesting
comment
on
an
alternative
approach
in
which
the
term
limit
of
detection
would
be
defined
at
§
136.2
as
``
the
critical
value,
which
is
the
concentration
at
which
there
is
99%
confidence
that
a
given
analyte
is
present
in
a
given
sample
matrix,''
and
the
method
detection
limit
would
be
defined
as
``
the
procedure
set
forth
in
Appendix
B
of
this
part,
which
can
be
used
to
estimate
the
limit
of
detection
(
i.
e.,
critical
value).''

B.
Technical
Revisions
to
the
MDL
Procedure
This
notice
proposes
several
technical
revisions
to
the
MDL
procedure
at
40
CFR
part
136,
Appendix
B.
These
revisions
are
based
on
EPA's
recent
assessment
of
detection
and
quantitation
concepts
described
in
the
Assessment
Document,
as
well
as
comments
received
from
stakeholders,
the
Petitioners,
and
the
peer
reviewers
of
the
assessment.
Specifically,
the
proposed
revisions
would:

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48
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March
12,
2003
/
Proposed
Rules
1.
Revise
the
definition
of
the
MDL
to
replace
the
term
``
minimum
concentration''
with
the
term
``
estimate
of
the
measured
concentration''
and
replace
the
phrase
``
greater
than
zero''
with
the
phrase
``
present
in
a
given
sample
matrix.''
The
revised
definition
would
note
the
functional
analogy
of
the
MDL
with
the
``
critical
value''
described
by
Currie
(
1968
and
1995)
and
the
``
limit
of
detection''
(
LOD)
described
by
the
American
Chemical
Society
in
1980
and
1983.
The
revised
definition
also
would
note
that
the
MDL
represents
the
concentration
at
which
the
detection
decision
is
made.
These
proposed
revisions
are
intended
to
make
the
definition
of
the
MDL
more
consistent
with
the
MDL
procedure.
The
proposed
revisions
reflect
peer
review
comments
on
EPA's
recent
assessment
of
detection
and
quantitation
concepts
and
procedures.
2.
Expand
the
Scope
and
Application
discussion
to
recognize
that
there
are
a
variety
of
purposes
and
analytical
methods
for
which
the
MDL
procedure
may
be
employed.
The
revised
text
provides
examples
of
four
common
uses
of
the
MDL
procedure
(
i.
e.,
demonstrating
laboratory
capability
with
a
particular
method;
monitoring
trends
in
laboratory
performance;
characterizing
method
sensitivity
in
a
particular
matrix;
and
establishing
an
MDL
for
a
new
or
revised
method
for
nationwide
use).
The
revised
text
also
clarifies
that
the
procedure
may
not
be
applicable
to
certain
test
methods
such
as
those
used
to
measure
pH
or
temperature,
for
example.
These
revisions
are
based
on
questions
from
stakeholders
about
the
scope
and
applicability
of
the
MDL
procedure.
3.
Revise
three
of
the
four
considerations
for
estimating
the
detection
limit
(
see
Step
1
of
the
current
MDL
procedure
and
section
4.3
of
the
proposed
revisions),
and
suggest
that
the
method­
specified
MDL
can
be
used
as
the
initial
estimate
when
performing
an
MDL
study
to
verify
laboratory
performance
or
to
demonstrate
that
the
MDL
can
be
achieved
in
a
specific
matrix.
The
proposed
revisions
to
the
original
considerations
include:
(
1)
Clarifying
that,
if
analysis
of
blank
samples
yields
an
instrument
response,
the
detection
limit
can
be
estimated
as
approximately
equal
to
three
times
the
standard
deviation
of
replicate
measurements
of
the
analyte
in
the
blank;
(
2)
replacing
``
that
region
of
the
standard
curve
where
there
is
a
significant
change
in
sensitivity
(
i.
e.,
a
break
in
the
slope
of
the
standard
curve)''
with
``
a
concentration
in
the
region
of
constant
or
effectivelyconstant
standard
deviation
at
low
concentrations;''
and
(
3)
replacing
``
instrumental
limitations''
with
``
the
lowest
concentration
that
can
be
detected
by
analyzing
samples
containing
successively
lower
concentrations
of
the
analyte.''
4.
Revise
the
specifications
for
establishing
the
test
concentration
range
according
to
the
intended
application
of
the
MDL
as
follows:
(
1)
If
verifying
a
published
MDL,
the
test
concentration
should
be
no
more
than
five
times
the
published
MDL;
(
2)
if
verifying
an
MDL
to
support
a
regulatory
objective
or
the
objective
of
a
study
or
program,
the
test
concentration
should
be
no
more
than
one
third
the
compliance
or
target
limit;
(
3)
if
determining
an
MDL
for
a
new
or
revised
method,
the
test
concentration
should
be
no
more
than
five
times
the
estimated
detection
limit;
and
(
4)
if
performing
an
iteration,
the
test
concentration
should
be
no
more
than
five
times
the
MDL
determined
in
the
most
recent
iteration.
(
See
Step
3.1
of
the
current
procedure
and
section
4.3.1
of
the
proposed
revisions.)
5.
Delete
the
calculation
of
a
95%
confidence
interval
estimate
for
the
MDL.
EPA
has
determined
that
these
calculations
are
neither
routinely
performed
by
laboratories,
nor
are
the
results
employed
by
regulatory
agencies,
including
EPA.
6.
Revise
the
discussion
of
the
iterative
procedure
to
require
that
the
iterative
procedure
be
used
to
verify
the
reasonableness
of
the
MDL
when
developing
an
MDL
for
a
new
or
revised
method
or
when
developing
a
matrixspecific
MDL,
but
that
it
remain
optional
when
determining
an
MDL
to
verify
a
method­,
matrix­,
program­,
or
study­
specific
MDL.
This
change
recognizes
that
the
iterative
procedure
is
rarely
used
to
verify
laboratory
performance,
but
is
considered
important
during
method
development.
The
discussion,
as
revised,
also
would
provide
specific
instructions
on
how
to
assess
the
reasonableness
of
an
MDL
used
to
verify
laboratory
performance.
(
See
Step
7
of
the
current
procedure
and
section
4.8
of
the
proposed
revision.)
7.
Add
a
new
section
(
section
4.9)
to
the
MDL
procedure
to
address
the
treatment
of
suspected
outliers.
EPA
is
proposing
to
add
this
section
in
response
to
frequent
questions
from
stakeholders
with
regard
to
outliers
in
the
absence
of
any
affirmative
statements
in
the
current
MDL
procedure.
The
discussion
in
this
proposed
section
specifies
that
suspected
outliers
be
examined
for
spurious
errors
that
may
occur
as
a
result
of
human
error
or
instrument
malfunction,
recommends
that
correctable
errors
be
corrected
before
calculation
of
the
MDL,
and
requires
that
any
corrective
actions
be
documented.
The
proposed
section
specifically
would
provide
for
invalidation
of
results
from
noncorrectable
errors
and
preclude
their
use
in
calculating
the
MDL.
The
proposed
section
also
describes
the
use
of
the
Grubbs
test
for
outlying
values
as
a
means
to
screen
the
results
of
the
replicate
samples
for
possible
outliers,
and
provides
an
example
application
of
the
Grubbs
test.
Finally,
the
proposed
section
would
reiterate
the
requirement
that
any
results
generated
from
more
than
seven
replicates
must
be
used
to
calculate
the
MDL
unless
they
are
determined
to
be
outliers
by
the
use
of
an
appropriate
outlier
test.
This
proposed
change
addresses
the
possibility
that
some
laboratories
could
prepare
more
than
the
requisite
seven
samples
and
then
select
only
the
seven
results
that
yield
the
most
desirable
MDL
value.
Laboratory
auditors
from
various
agencies
have
identified
this
practice
as
a
problem
that
can
distort
the
MDL,
but
it
is
not
specifically
prohibited
or
addressed
in
the
current
procedure.
8.
Delete
the
discussion
of
analysis
and
use
of
blanks
included
in
section
4(
a)
of
the
current
procedure.
The
current
discussion
applies
to
methods
in
which
a
blank
measurement
is
required
to
calculate
the
measured
level
of
an
analyte;
it
requires
separate
measurements
of
blank
samples
for
each
MDL
sample
aliquot
analyzed
and
subtraction
of
the
average
result
of
the
blank
samples
from
each
respective
MDL
sample
measurement.
The
proposed
deletion
of
this
discussion
is
in
recognition
that
subtraction
of
a
single
(
or
average)
blank
sample
result
from
the
result
for
each
MDL
sample
would
not
change
the
standard
deviation
and
thus,
would
have
no
effect
on
the
resulting
MDL.
Although
EPA
believes
laboratories
would
be
prudent
to
analyze
blanks
for
assessing
potential
contamination,
EPA
also
believes
that
requiring
analysis
of
blanks
or
subtraction
of
blank
results
during
MDL
determinations
is
unnecessarily
burdensome.
9.
Revise
the
optional
pre­
test
described
in
section
4(
b)
of
the
current
procedure.
The
current
procedure
suggests
analyzing
two
aliquots
to
evaluate
the
estimated
detection
limit
before
proceeding
with
the
full
sevenreplicate
test.
Results
from
these
analyses
are
evaluated
to
determine
if
the
sample
is
in
the
``
desirable
range
for
determining
the
MDL,''
but
no
criteria
are
provided
for
establishing
this
desirable
range.
The
proposed
revisions
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Proposed
Rules
to
the
pre­
test
procedure
are
intended
to
address
this
issue.
These
revisions
now
appear
in
section
4.1
of
the
proposed
procedure.
Specifically,
the
pre­
test
has
been
modified
to
suggest
analysis
of
three
aliquots.
Results
from
these
analyses
are
evaluated
by
calculating
a
preliminary
MDL
based
on
the
standard
deviation
of
the
analyses,
and
then
determining
if
this
preliminary
MDL
is
within
0.2
to
1.0
times
the
concentration
spiked
in
the
sample.
This
revision
is
consistent
with
the
current
procedure's
recommendation
that
samples
used
to
determine
an
MDL
contain
the
analyte
at
a
concentration
that
is
``
between
1
and
5
times
the
estimated
method
detection
limit.''

C.
Editorial
Changes
to
the
MDL
Procedure
This
notice
proposes
editorial
changes
to
the
MDL
procedure
at
40
CFR
part
136,
Appendix
B
that
are
designed
to
clarify
the
existing
procedure
and
improve
readability.
These
editorial
changes
include
changes
to
the
numbering
scheme,
the
addition
of
clearer
titles
to
some
of
the
procedural
steps,
and
minor
clarifications.
Specifically,
the
proposed
changes
would:
1.
Add
a
summary
section
to
provide
an
overview
of
the
various
steps
included
in
the
MDL
procedure.
The
summary
section
is
consistent
with
the
current
format
for
analytical
methods
and
should
be
particularly
helpful
to
non­
laboratory
readers.
2.
Clarify
in
the
Scope
and
Application
discussion
that
the
MDL
procedure
is
intended
for
use
in
EPA's
Clean
Water
Act
programs,
and
that
alternative
procedures
may
be
used
to
establish
test
method
sensitivity
provided
the
resulting
detection
value
meets
the
sensitivity
needs
for
a
specific
application.
3.
Clarify
throughout
the
procedure
that
not
all
of
the
steps
are
required
for
every
application.
This
clarification
provides
consistency
with
the
proposed
revisions
in
the
Scope
and
Application
section
of
the
procedure.
4.
Expand
the
discussion
of
matrix
selection
to
address
use
of
an
MDL
in
either
a
reference
matrix
or
an
alternate
matrix.
(
See
Step
2
of
the
current
procedure
and
section
4.2
of
the
proposed
revisions.)
Use
of
matrices
other
than
reagent
water
are
not
discussed
until
Step
3b
of
the
current
procedure.
The
expanded
discussion
is
intended
to
provide
additional
clarity
and
consistency
with
the
description
of
the
four
applications
added
to
the
MDL
Scope
and
Application
section
(
see
section
VII.
B.
2
above).
5.
Expand
the
discussion
of
establishing
the
test
concentration
range
to
more
clearly
describe
the
steps
required
and
prepare
the
test
samples.
(
See
Step
3
of
the
current
procedure
and
section
4.3
of
the
proposed
revisions.)
These
proposed
changes
are
editorial
and
describe
the
process
that
may
be
used
for
determining
a
matrix­
specific
MDL
as
well
as
determining
an
MDL
in
a
reference
matrix
such
as
reagent
water.
Additional
clarifications
include
recognition
that
some
analytes
may
require
that
seven
aliquots
be
prepared
individually,
as
opposed
to
preparing
a
bulk
sample
of
sufficient
volume
to
be
split
into
seven
aliquots.
EPA
is
proposing
this
clarification
in
response
to
questions
from
laboratories
regarding
the
appropriate
means
for
preparing
the
MDL
aliquots.
6.
Expand
the
discussion
of
performing
the
analyses
to
include
a
brief
introduction
clarifying
that
the
samples
used
for
MDL
analyses
must
be
processed
using
the
sample
handling,
processing,
and
result
calculations
specified
in
the
analytical
method.
(
See
Step
4
of
the
current
procedure
and
section
4.4
of
the
proposed
revisions.)
This
proposed
change
includes
moving
this
statement
from
the
Reporting
section
of
the
current
procedure
to
the
more
appropriate
location
in
section
4
of
the
revised
procedure.
This
proposed
change
also
would
clarify
that
blankcorrection
or
recovery­
correction
procedures
are
applied
to
the
MDL
analyses
only
when
those
procedures
are
employed
for
routine
sample
analyses,
and
precludes
their
use
if
they
are
not
specified
in
the
test
method.
EPA
is
proposing
these
changes
in
response
to
questions
raised
by
laboratories,
the
Petitioners,
and
as
a
result
of
the
recent
assessment.
7.
Reorganize
the
procedural
steps
contained
in
Step
4
of
the
current
procedure,
such
that
the
optional
pretest
of
the
MDL
is
discussed
before
the
procedure
for
performing
the
full
sevenreplicate
test.
(
See
section
4.4
of
the
proposed
revisions.)
EPA
is
proposing
this
change
strictly
to
improve
ease
of
use.
8.
Expand
and
reorganize
the
description
of
the
seven­
replicate
version
of
the
MDL
described
in
Step
4(
a)
of
the
current
procedure.
The
revised
version
would
appear
in
section
4.5
and
reflects
comments
from
stakeholders
that
the
discussion
in
the
current
procedure
is
not
sufficiently
clear.
The
revised
procedure
also
would
state
explicitly
that
all
analytical
results
must
be
positive
numbers,
and
that
the
results
from
all
aliquots
analyzed
must
be
used
in
the
calculations,
except
those
identified
as
outliers
using
the
procedures
described
in
section
4.9
of
the
revised
procedure
(
see
the
discussion
regarding
outliers
in
VII.
B
above).
These
proposed
changes
would
clarify
stakeholder
concerns
regarding
those
analytical
methods
(
e.
g.,
for
metals)
that
may
produce
negative
numbers
at
very
low
concentrations
and
would
emphasize
the
revision
made
in
response
to
concerns
regarding
inappropriate
screening
of
results
used
for
MDL
determinations.
9.
Simplify
the
calculations
of
standard
deviation
of
replicate
measurements
in
Step
5
of
the
current
procedure.
(
See
section
4.6
of
the
proposed
revisions.)
For
example,
the
current
procedure
details
the
calculation
of
the
sample
variance
(
s2),
and
then
details
the
calculation
of
the
sample
standard
deviation
(
s)
in
a
separate
equation.
Given
that
the
variance
term
does
not
factor
into
the
MDL
calculation
directly,
the
proposed
revision
would
require
only
calculation
of
the
standard
deviation.
The
proposed
revision
also
would
include
a
caution
warning
the
reader
to
calculate
the
sample
standard
deviation
(
s),
not
the
population
standard
deviation
(
sigma),
when
using
automated
programs
such
as
spreadsheets.
This
error
was
not
as
likely
to
occur
in
1984,
prior
to
the
ready
availability
of
personal
computers
and
laboratory
data
systems,
but
is
commonly
seen
today.
10.
Move
the
table
of
Student's
tvalues
from
its
current
location
following
the
text
in
Step
7
to
section
4.7,
where
the
t­
value
is
employed.
EPA
is
proposing
this
change
to
improve
ease
of
use
and
increase
readability.
11.
Add
a
table
of
F­
statistic
values
to
the
iterative
procedure
described
in
section
4.8.
EPA
is
proposing
this
change
to
improve
ease
of
use
and
address
those
instances
in
which
an
iterative
MDL
might
be
determined
from
other
than
seven
replicates
per
data
set.
12.
Delete
the
``
Reporting''
section
of
the
MDL
procedure.
The
existing
procedure
includes
a
section
listing
the
information
that
must
be
provided
with
the
MDL
for
each
analyte.
EPA
is
proposing
to
delete
this
section
because
it
is
not
relevant
to
the
procedure
and
it
is
generally
duplicative
of
reporting
and
recordkeeping
requirements
that
States,
other
regulatory
entities,
or
laboratory
certification
officials
already
require.

D.
Definition
and
Procedure
for
Determining
the
Minimum
Level
of
Quantitation
Although
ML
values
for
analytes
were
published
in
1984
in
EPA
Methods
1624
and
1625
(
49
FR
43234,
October
26,
1984),
the
definition
of
the
ML
was
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Proposed
Rules
provided
in
a
footnote
to
the
tables
within
those
methods.
The
original
definition
was
intended
to
define
a
minimum
level
of
quantitation
for
these
isotope
dilution
GC/
MS
methods.
However,
as
described
in
the
Assessment
Document,
EPA
has
changed
the
definition
of
the
ML
over
the
years
and
has
expanded
its
applicability
to
other
40
CFR
part
136
methods.
This
proposal
requests
comment
on
whether
to
add
the
following
definition
of
the
ML
to
Appendix
B
of
40
CFR
part
136:
``
the
lowest
level
at
which
the
entire
analytical
system
gives
a
recognizable
signal
and
acceptable
calibration
point
for
the
analyte,
as
determined
by
the
procedure
set
forth
at
Appendix
B
of
this
part.
The
ML
represents
the
lowest
concentration
at
which
an
analyte
can
be
measured
with
a
known
level
of
confidence.''
In
addition
to
the
definition,
EPA
requests
comment
on
whether
Appendix
B
should
contain
an
explicit
explanation
of
the
calculation
of
the
ML
from
an
MDL
value
determined
using
the
revised
MDL
procedure,
including
a
table
of
multiplier
values
that
may
be
used
when
the
MDL
value
is
calculated
from
other
than
seven
replicate
analyses.
An
alternative
is
to
not
incorporate
a
definition
in
§
136.2
but
to
continue
to
specify
the
ML
on
a
method­
by­
method
basis.
In
this
case,
the
ML
may
continue
to
be
determined
and
supported
with
data
gathered
during
method
validation
studies.
This
approach
would
allow
maximum
flexibility
to
design
studies
that
are
appropriate
for
the
intended
use
of
the
method.
A
second
alternative
is
to
incorporate
into
§
136.2
the
definition
of
limit
of
quantitation
as
``
The
lowest
concentration
of
an
analyte
that
can
be
measured
with
a
defined
level
of
confidence''
and
to
incorporate
the
definition
of
ML
(
minimum
level)
as
``
The
procedure
set
forth
in
Appendix
B
of
this
part
of
the
same
name,
which
can
be
used
to
estimate
the
limit
of
quantitation.''
In
this
proposal,
EPA
is
also
requesting
comment
on
whether
it
should
encourage
or
require
that
laboratories
periodically
demonstrate
target
analyte
recovery
at
the
ML
by
preparing
and
analyzing
a
reference
matrix
sample
spiked
at
the
ML
using
all
sample
handling
and
processing
steps
described
in
the
method.
EPA
recognizes
that
existing
methods
do
not
provide
acceptance
criteria
for
such
``
ML
standards.''
Therefore,
EPA
suggests
that,
if
the
method
does
not
provide
acceptance
criteria
for
an
ML
standard,
acceptance
criteria
for
other
spiked
reference
matrix
samples
(
e.
g.,
laboratory
control
samples,
laboratory
fortified
blanks,
ongoing
precision
and
recovery
samples,
etc.)
may
be
used
to
evaluate
analyte
recovery
at
the
ML.
EPA
is
soliciting
comment
on
whether
this
recommendation
should
be
made
into
a
mandatory
requirement,
retained
as
a
recommendation,
or
replaced
by
an
alternative
recommendation
for
demonstrating
recovery
at
the
ML.

E.
Acceptance
of
Test
Methods
Employing
Alternative
Detection
and
Quantitation
Procedures
This
proposed
rule
would
allow
use
of
alternative
detection
and
quantitation
procedures
to
establish
detection
and
quantitation
limits
in
an
analytical
method,
provided
that
the
resulting
detection
and
quantitation
limits
meet
the
sensitivity
needs
for
the
specific
application.
The
use
of
detection
and
quantitation
approaches
from
voluntary
consensus
standards
bodies
(
VCSBs)
and
other
organizations
is
encouraged
under
the
National
Technology
Transfer
and
Advancement
Act
(
NTTAA),
because
it
facilitates
the
approval
of
analytical
methods
from
these
organizations
at
40
CFR
part
136
without
requiring
that
these
organizations
specifically
employ
EPA's
MDL
and
ML
procedures
to
establish
method
sensitivity.
This
allowance
would
result
in
greater
flexibility
to
establish
or
improve
the
sensitivity
of
methods
for
use
under
the
Clean
Water
Act.
It
also
would
facilitate
approval
of
analytical
methods
from
VCSBs
and
other
organizations.
In
selecting
an
appropriate
test
method
for
a
specific
purpose,
the
laboratory
must
always
consider
the
sensitivity
of
the
approved
test
methods.
Only
those
test
methods
with
the
desired
sensitivity
should
be
used
to
meet
the
objective
of
the
CWA
``
to
restore
and
maintain
the
chemical,
physical,
and
biological
integrity
of
the
Nation's
waters.''
EPA
recognizes
that
there
are
alternative
detection
and
quantitation
approaches
that
may
be
used
for
determining
test
method
sensitivity.
EPA
has
included
test
methods
at
40
CFR
part
136
that
employ
alternative
approaches,
although
some
of
these
approaches
have
not
been
rigorously
defined.
In
its
recent
assessment
of
detection
and
quantitation
approaches,
EPA
evaluated
the
interlaboratory
detection
estimate
(
IDE)
and
the
interlaboratory
quantitation
estimate
(
IQE)
procedures
published
by
ASTM
International.
However,
EPA
is
not
aware
at
this
time
of
any
published
test
methods
from
any
source
that
include
specific
values
for
the
IDE
and
the
IQE,
including
test
methods
published
by
ASTM
International.
EPA
will
consider
test
methods
that
include
these
procedures
for
use
in
CWA
programs
when
such
methods
are
available.
If
ASTM
International
is
successful
in
developing
single­
laboratory
adaptations
of
the
IDE
and
IQE
that
may
be
used
to
verify
the
ability
of
a
given
laboratory
to
achieve
the
IDE
and
IQE,
then
EPA
also
may
consider
those
single­
laboratory
approaches
in
evaluating
both
method
and
laboratory
performance.

VIII.
Industry
Proposal
On
December
27,
2002,
the
Inter­
Industry
Analytical
Group
(
IIAG)
submitted
a
proposal
that
recommends
(
1)
a
sensitivity
test
intended
to
``
replace
the
MDL
as
a
test
of
whether
an
individual
laboratory
is
performing
adequately,''
and
(
2)
an
interlaboratory
validation
study
design
intended
to
characterize
precision
and
accuracy
of
methods
used
for
regulatory
compliance.
EPA
did
not
have
the
opportunity
to
evaluate
IIAG's
proposal
against
the
criteria
discussed
in
Section
IV
of
this
preamble,
but
intends
to
do
so
prior
to
publication
of
a
final
rule.
EPA
is
providing
a
summary
of
the
recommendations
contained
in
the
``
Inter­
Industry
Analytical
Group
Proposal
for
Sensitivity
Test
and
Full­
Range
Interlaboratory
Validation
Study''
here.
The
complete
text
of
the
recommendations
has
been
placed
in
the
docket
supporting
this
proposed
rule.
EPA
is
soliciting
comment
on
the
industry
recommendations.
IIAG
is
proposing
a
sensitivity
test
in
place
of
the
MDL
for
determining
laboratory
performance
capability.
The
proposed
sensitivity
test
includes
the
provision
that
EPA
first
determine
the
lowest
calibration
point
of
a
method,
prescribe
a
dilution
of
that
calibration
point
as
the
spike
level
(
e.
g.,
at
one­
half
or
two­
thirds
the
lowest
calibration
point),
specify
a
required
number
of
replicates,
and
set
a
quality
control
acceptance
criterion.
IIAG
asserts
that
an
advantage
of
such
a
test
is
that
it
would
provide
all
laboratories
with
a
single
spike
level
and
an
``
unambiguous
pass
or
no­
pass
test.''
EPA
is
soliciting
comment
on
approaches
that
might
be
considered
appropriate
for
such
determinations
(
i.
e.,
the
lowest
calibration
point
of
a
method,
an
appropriate
dilution,
a
number
of
replicates,
and
an
acceptance
criterion
for
standard
deviation
between
measurements
of
the
replicates).
EPA
also
is
soliciting
comment
on
how
IIAG's
recommended
sensitivity
test
would
be
either
more
appropriate
or
less
appropriate
than
either
the
current
MDL
and
ML
procedures
or
the
MDL
and
ML
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procedures
if
revised
according
to
this
proposed
rule.
IIAG's
proposed
``
full
range''
validation
study
is
intended
to
determine
precision
and
bias
across
the
entire
working
range
of
an
analytical
method
(
i.
e.,
from
a
blank
to
the
upper
end
of
the
working
range)
and
would
account
for
variability
between
laboratories.
IIAG
recommends
that,
unlike
the
MDL
and
IIAG's
proposed
sensitivity
test,
the
``
full­
range''
validation
study
could
be
used
to
characterize
bias
and
precision
across
the
entire
working
range
of
the
method
and
results
of
such
a
study
could
be
used
to
establish
an
interlaboratory
method
detection
level.
EPA
is
requesting
comment
on
the
use
of
data
generated
through
a
``
full
range''
validation
study
to
determine
a
quantitation
level,
detection
level,
and
corresponding
bias
and
precision
criteria
that
are
applicable
throughout
the
entire
working
range
of
the
method.
EPA
also
is
soliciting
comment
on
how
IIAG's
recommended
``
full
range''
validation
study
would
be
either
more
appropriate
or
less
appropriate
than
EPA's
use
of
interlaboratory
validation
studies,
which
are
designed
in
accordance
with
ASTM
Standard
D
2777,
or
other
appropriate
standards.
For
example,
EPA
used
the
ASTM
standard
to
validate
EPA
Method
1631
(
see
Interlaboratory
Validation
Study
of
EPA
Method
1631).

IX.
Solicitation
of
Comments
EPA
is
hereby
requesting
public
comment
on
the
proposed
revisions
discussed
in
section
VII
of
this
preamble
and
on
the
industry
proposal
discussed
in
section
VIII.
Specifically,
EPA
is
requesting
comment
on
the
proposed
revisions
to
the
Definition
and
Procedure
for
the
Determination
of
the
Method
Detection
Limit
at
40
CFR
part
136
(
Appendix
B),
to
the
proposed
revision
to
the
definition
of
``
Detection
Limit,''
on
whether
EPA
should
add
definition
of
``
Minimum
Level''
at
40
CFR
136.2,
and
on
whether
and
how
the
sensitivity
test
described
in
the
industry
proposal
could
be
used
in
CWA
programs.
EPA
is
also
requesting
public
comment
on
the
Assessment
Document
supporting
the
proposed
revisions
discussed
in
this
notice
elsewhere
in
today's
Federal
Register
(
see
Notice
of
Document
Availability
and
Public
Comment
Period
for
the
Technical
Support
Document
for
the
Assessment
of
Detection
and
Quantitation
Concepts).
Commenters
are
encouraged
to
support
their
views
with
data
or
information
that
would
assist
EPA
in
making
a
final
decision
on
detection
and
quantitation
procedures
for
EPA's
CWA
applications.
To
ensure
that
EPA
can
properly
respond
to
comments,
commenters
should
cite,
where
possible,
the
paragraph(
s)
or
section(
s)
in
this
proposal
to
which
each
comment
refers.
For
further
details
on
submission
of
comments,
please
see
the
DATES;
ADDRESSES;
and
``
How
to
Submit
Comments''
sections
at
the
beginning
of
this
preamble.
EPA
is
particularly
requesting
comment
on
the
following:
1.
EPA
is
requesting
comment
on
whether
to
include
a
definition
and
procedure
for
the
ML
in
Appendix
B
of
40
CFR
part
136
(
see
section
VII.
D
of
this
preamble).
EPA
is
soliciting
comment
on
whether
the
proposed
addition
of
an
ML
definition
and
procedure
in
Appendix
B
is
appropriate,
or
whether
either
of
the
alternatives
discussed
in
section
VII.
D
are
more
appropriate
to
maintain
flexibility
in
the
application
of
different
quantitation
approaches.
2.
EPA
is
proposing
a
recommendation
that
laboratories
periodically
demonstrate
target
analyte
recovery
at
the
ML
by
preparing
and
analyzing
a
reference
matrix
sample
spiked
at
the
ML
(
see
section
VII.
D
of
this
preamble).
Specifically,
EPA
is
soliciting
comment
on
whether
this
recommendation
should
be
made
into
a
mandatory
requirement,
retained
as
a
recommendation,
or
replaced
by
an
alternative
recommendation
for
demonstrating
recovery
at
the
ML.
EPA
also
is
soliciting
comments
and
recommendations
regarding
procedures
for
establishing
acceptance
criteria
for
ML
recovery,
and
when
application
of
the
criteria
would
be
appropriate
(
e.
g.,
development
of
new
methods,
validation
of
data),
if
such
a
requirement
were
mandatory.
3.
EPA
is
proposing
to
add
a
new
Step
8
to
the
MDL
procedure
to
address
the
identification
and
treatment
of
suspected
outliers
(
see
Section
VII.
B.
7
of
this
preamble).
This
proposed
step
includes
provision
for
invalidation
of
results
from
noncorrectable
errors
and
precludes
their
use
in
calculating
the
MDL.
The
proposed
step
also
states:
``
Given
the
small
number
of
replicates
typically
used
to
determine
the
MDL,
it
is
inappropriate
to
use
a
data
set
that
contains
more
than
one
statistical
outlier.''
EPA
requests
comment
on
(
1)
the
procedures
for
identifying
outliers,
(
2)
the
specification
that
only
one
outlier
may
be
removed
from
a
data
set
that
is
used
for
MDL
determination,
and
(
3)
the
appropriateness
of
allowing
use
of
a
data
set
containing
six
results
if
an
outlier
is
identified
and
removed
from
a
data
set
containing
results
from
the
required
minimum
of
seven
replicate
samples.
4.
EPA
is
proposing
to
revise
the
specifications
for
establishing
the
test
concentration
(
spike
level)
that
will
be
used
in
the
determining
the
MDL
according
to
the
intended
application
of
the
MDL
(
see
Section
VII.
A.
4
of
this
preamble).
EPA
is
soliciting
comment
on
these
levels
and
on
the
appropriateness
of
applying
these
levels
according
to
the
intended
use
of
the
MDL.
5.
EPA
is
soliciting
comment
on
the
sensitivity
test
and
``
full­
range''
validation
study
described
by
IIAG
and
included
in
the
public
docket
supporting
this
proposed
rule
(
see
Section
VII
of
this
preamble).
EPA
is
specifically
soliciting
comment
on
those
aspects
of
IIAG's
proposed
study
that
relate
to
detection
and
quantitation
issues.
6.
EPA
is
proposing
to
delete
the
Reporting
section
of
the
existing
MDL
procedure.
EPA
is
soliciting
comments
on
whether
this
change
is
appropriate.

X.
Statutory
and
Executive
Order
Reviews
A.
Executive
Order
12866:
Regulatory
Planning
and
Review
Under
Executive
Order
12866
(
58
FR
51735
(
October
4,
1993)),
the
Agency
must
determine
whether
the
regulatory
action
is
``
significant''
and
therefore
subject
to
Office
of
Management
and
Budget
(
OMB)
review
and
the
requirements
of
the
Executive
Order.
The
Executive
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.
It
has
been
determined
that
this
rule
is
not
a
``
significant
regulatory
action''
under
the
terms
of
Executive
Order
12866
and
is
therefore
not
subject
to
OMB
review.

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B.
Paperwork
Reduction
Act
This
action
does
not
impose
an
information
collection
burden
under
the
provisions
of
the
Paperwork
Reduction
Act,
44
U.
S.
C.
3501
et
seq.
This
action
imposes
no
information
collection,
reporting
or
recordkeeping
requirements.
Burden
means
the
total
time,
effort,
or
financial
resources
expended
by
persons
to
generate,
maintain,
retain,
or
disclose
or
provide
information
to
or
for
a
Federal
agency.
This
includes
the
time
needed
to
review
instructions;
develop,
acquire,
install,
and
utilize
technology
and
systems
for
the
purposes
of
collecting,
validating,
and
verifying
information,
processing
and
maintaining
information,
and
disclosing
and
providing
information;
adjust
the
existing
ways
to
comply
with
any
previously
applicable
instructions
and
requirements;
train
personnel
to
be
able
to
respond
to
a
collection
of
information;
search
data
sources;
complete
and
review
the
collection
of
information;
and
transmit
or
otherwise
disclose
the
information.
An
Agency
may
not
conduct
or
sponsor,
and
a
person
is
not
required
to
respond
to
a
collection
of
information,
unless
it
displays
a
currently
valid
OMB
control
number.
The
OMB
control
numbers
for
EPA's
regulations
are
listed
in
40
CFR
part
9
and
48
CFR
chapter
15.

C.
Regulatory
Flexibility
Act
The
Regulatory
Flexibility
Act
(
RFA)
generally
requires
an
agency
to
prepare
a
regulatory
flexibility
analysis
of
any
rule
subject
to
notice
and
comment
rulemaking
requirements
under
the
Administrative
Procedure
Act
or
any
other
statute
unless
the
agency
certifies
that
the
rule
will
not
have
a
significant
economic
impact
on
a
substantial
number
of
small
entities.
Small
entities
include
small
businesses,
small
organizations,
and
small
governmental
jurisdictions.
For
purposes
of
assessing
the
impacts
of
this
rule
on
small
entities,
small
entity
is
defined
as:
(
1)
A
small
business
as
defined
by
the
U.
S.
Small
Business
Administration
definitions
at
13
CFR
121.201;
(
2)
a
small
governmental
jurisdiction
that
is
a
government
of
a
city,
county,
town,
school
district
or
special
district
with
a
population
of
less
than
50,000;
and
(
3)
a
small
organization
that
is
any
not­
for­
profit
enterprise
which
is
independently
owned
and
operated
and
is
not
dominant
in
its
field.
After
considering
the
economic
impacts
of
this
proposed
rule
on
small
entities,
I
certify
that
this
action
will
not
have
a
significant
economic
impact
on
a
substantial
number
of
small
entities.
This
rule
proposes
to
modify
existing
procedures
in
40
CFR
part
136,
appendix
B
for
determination
of
detection
and
quantitation
in
analytical
methods.
This
modification
would
clarify
and
improve
existing
procedures.
Overall,
the
costs
of
this
modification
are
minimal.
Many
laboratories
using
analytical
test
methods
are
already
implementing
aspects
of
the
modification,
further
minimizing
any
potential
cost
increases.
Therefore,
EPA
believes
that
this
rule
will
not
have
a
significant
economic
impact
on
a
substantial
number
of
small
entities.
We
continue
to
be
interested
in
the
potential
impacts
of
the
proposed
rule
on
small
entities
and
welcome
comments
on
issues
related
to
such
impacts.

D.
Unfunded
Mandates
Reform
Act
Title
II
of
the
Unfunded
Mandates
Reform
Act
of
1995
(
UMRA),
Public
Law
104
 
4,
establishes
requirements
for
Federal
agencies
to
assess
the
effects
of
their
regulatory
actions
on
State,
Tribal,
and
local
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,
Tribal,
and
local
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
of
why
that
alternative
was
not
adopted.
Before
EPA
establishes
any
regulatory
requirements
that
may
significantly
or
uniquely
affect
small
governments,
including
Tribal
governments,
it
must
have
developed
under
section
203
of
the
UMRA
a
small
government
agency
plan.
The
plan
must
provide
for
the
notification
of
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.
This
proposed
rule
contains
no
Federal
mandate
(
under
the
regulatory
provisions
of
Title
II
of
the
UMRA)
for
State,
Tribal,
and
local
governments
or
the
private
sector
in
any
one
year.
This
rule
imposes
no
enforceable
duty
on
any
State,
local,
or
Tribal
governments
or
the
private
sector.
This
rule
proposes
to
modify
existing
procedures
in
40
CFR
part
136,
appendix
B
for
determination
of
detection
and
quantitation
in
analytical
methods.
This
modification
would
clarify
and
improve
current
procedures.
Overall,
the
costs
of
this
modification
are
minimal.
Thus,
this
rule
is
not
subject
to
sections
202
and
205
of
the
UMRA.
For
the
same
reasons,
EPA
has
also
determined
that
this
rule
contains
no
regulatory
requirements
that
might
significantly
or
uniquely
affect
small
governments.
Thus,
this
rule
also
is
not
subject
to
the
requirements
of
section
203
of
the
UMRA.

E.
Executive
Order
13132:
Federalism
Executive
Order
13132,
entitled
``
Federalism''
(
64
FR
43255,
August
10,
1999),
requires
EPA
to
develop
an
accountable
process
to
ensure
``
meaningful
and
timely
input
by
State
and
local
officials
in
the
development
of
regulatory
policies
that
have
federalism
implications.''
``
Policies
that
have
federalism
implications''
is
defined
in
the
Executive
Order
to
include
regulations
that
have
``
substantial
direct
effects
on
the
States,
on
the
relationship
between
the
national
government
and
the
States,
or
on
the
distribution
of
power
and
responsibilities
among
the
various
levels
of
government.''
This
proposed
rule
does
not
have
federalism
implications.
It
will
not
have
substantial
direct
effects
on
the
States,
on
the
relationship
between
the
national
government
and
the
States,
or
on
the
distribution
of
power
and
responsibilities
among
the
various
levels
of
government,
as
specified
in
Executive
Order
13132.
This
rule
proposes
to
modify
existing
procedures
in
40
CFR
part
136,
Appendix
B
for
determination
of
detection
and
quantitation
in
analytical
methods.
This
modification
would
clarify
and
improve
existing
procedures.
The
costs
of
this
rule
for
State
and
local
governments
are
minimal.
Thus,
Executive
Order
13132
does
not
apply
to
this
rule.
In
the
spirit
of
Executive
Order
13132,
and
consistent
with
EPA
policy
to
promote
communications
between
EPA
and
State
and
local
governments,
EPA
specifically
solicits
comments
on
this
proposed
rule
from
State
and
local
officials.

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Proposed
Rules
F.
Executive
Order
13175:
Consultation
and
Coordination
with
Indian
Tribal
Governments
Executive
Order
13175,
titled
``
Consultation
and
Coordination
With
Indian
Tribal
Governments''
(
65
FR
67249,
November
9,
2000),
requires
EPA
to
develop
an
accountable
process
to
ensure
``
meaningful
and
timely
input
by
Tribal
officials
in
the
development
of
regulatory
policies
that
have
Tribal
implications.''
``
Policies
that
have
Tribal
implications''
is
defined
in
the
Executive
Order
to
include
regulations
that
have
``
substantial
direct
effects
on
one
or
more
Indian
Tribes,
on
the
relationship
between
the
Federal
government
and
the
Indian
Tribes,
or
on
the
distribution
of
power
and
responsibilities
between
the
Federal
government
and
Indian
Tribes.''
This
proposed
rule
does
not
have
Tribal
implications.
It
will
not
have
substantial
direct
effects
on
Tribal
governments,
on
the
relationship
between
the
Federal
government
and
Indian
Tribes,
or
on
the
distribution
of
power
and
responsibilities
between
the
Federal
government
and
Indian
Tribes,
as
specified
in
Executive
Order
13175.
This
rule
proposes
to
modify
existing
procedures
in
40
CFR
part
136,
Appendix
B
for
determination
of
detection
and
quantitation
in
analytical
methods.
This
modification
would
clarify
and
improve
existing
procedures.
The
costs
of
this
rule
for
Tribal
governments
are
minimal.
Thus,
Executive
Order
13175
does
not
apply
to
this
rule.
In
the
spirit
of
Executive
Order
13175,
and
consistent
with
EPA
policy
to
promote
communications
between
EPA
and
Tribal
governments,
EPA
specifically
solicits
comments
on
this
proposed
rule
from
Tribal
officials.

G.
Executive
Order
13045:
Protection
of
Children
From
Environmental
Health
&
Safety
Risks
Executive
Order
13045
(
62
FR
19885,
April
23,
1997)
applies
to
any
rule
that:
(
1)
Is
determined
to
be
``
economically
significant''
as
defined
under
Executive
Order
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.
This
proposed
rule
is
not
subject
to
Executive
Order
13045
because
it
is
not
``
economically
significant''
as
defined
in
Executive
Order
12866.
Furthermore,
it
does
not
concern
an
environmental
health
or
safety
risk
that
EPA
has
reason
to
believe
may
have
a
disproportionate
effect
on
children.

H.
Executive
Order
13211:
Actions
That
Significantly
Affect
Energy
Supply,
Distribution,
or
Use
This
rule
is
not
subject
to
Executive
Order
13211,
``
Actions
Concerning
Regulations
That
Significantly
Affect
Energy
Supply,
Distribution,
or
Use''
(
66
FR
28355
(
May
22,
2001))
because
it
is
not
a
significant
regulatory
action
under
Executive
Order
12866.

I.
National
Technology
Transfer
and
Advancement
Act
Section
12(
d)
of
the
National
Technology
Transfer
and
Advancement
Act
of
1995,
(``
NTTAA''),
Public
Law
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.,
material
specifications,
test
methods,
sampling
procedures,
business
practices)
that
are
developed
or
adopted
by
voluntary
consensus
standard
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
proposed
rulemaking
involves
technical
standards.
Therefore,
the
Agency
identified
and
evaluated
potential
voluntary
consensus
standards.
Specifically,
EPA
identified
and
evaluated
potential
detection
and
quantitation
concepts
and
procedures
published
by
the
American
Society
for
Testing
and
Materials
(
ASTM
International),
from
the
International
Organization
for
Standardization
(
ISO),
the
International
Union
of
Pure
and
Applied
Chemistry
(
IUPAC),
and
the
American
Chemical
Society
(
ACS).
EPA
determined
that,
although
ISO,
IUPAC,
and
ACS
have
published
terms
and
definitions
for
detection
and
quantitation,
these
organizations
have
not
published
an
applicable
standard
(
i.
e.,
a
step­
by­
step
protocol
to
make
a
detection
or
quantitation
determination).
EPA
did
identify
applicable
standards
from
ASTM
International
(
the
IDE
and
IQE).
This
proposed
rulemaking
would
allow
the
use
of
these
procedures
for
methods
development
purposes
and
would
allow
the
use
of
any
analytical
methods
with
an
IDE
and
IQE,
provided
these
test
methods
meet
the
analytical
sensitivity
requirements
for
a
specific
data
use.
There
is
currently
no
applicable
voluntary
consensus
standard
for
detection
and
quantitation
for
laboratory
quality
control
purposes.
EPA
welcomes
comments
on
this
aspect
of
the
proposed
rulemaking
and,
specifically,
invites
the
public
to
identify
potentially
applicable
voluntary
consensus
standards
and
to
explain
why
such
standards
should
be
used
in
this
regulation.

XI.
References
American
Chemical
Society,
1980:
Analytical
Chemistry
1980,
52,
2242
 
2249.
American
Chemical
Society,
1983:
Analytical
Chemistry
1983,
55,
2210
 
2218.
Budde,
William
L.,
Environmental
Science
and
Technology
1981
15,
1426
 
1435.
Currie,
1968:
Currie,
Lloyd
A.
Anal.
Chem.
1968
40,
586
 
593.
Currie,
1999:
Currie,
Lloyd
A.
Anal.
Chim.
Acta
1999
391,
127
 
134.
Gibbons,
1997:
Gibbons,
Robert
D.;
Coleman,
David
E.;
Maddalone,
Raymond
F.
Env.
Sci.
Technol.
1997,
31,
2071
 
2077).
Glaser,
1981:
Glaser,
John
A.,
Foerst,
Denis
L.,
McKee,
Gerald
D.,
Quave,
Stephan
A.,
and
Budde,
William
L.
(
1981),
Environ.
Sci.
Technol.,
15:
1426.
Kahn,
1998:
Kahn,
Henry
D.;
Telliard,
William
A.;
White,
Charles
E.
Env.
Sci.
Technol.
1998
32,
2346
 
2348.
Kahn,
1998:
Kahn,
Henry
D.;
Telliard,
William
A.;
White,
Charles
E.
Env.
Sci.
Technol.
1999
33,
1315.
Maddalone,
1993:
Maddalone,
Raymond
F.;
Rice,
James
K.;
Edmondson,
Ben
C.;
Nott,
Babu
R.;
Scott,
Judith
W.
Water
Environment
and
Technology
1993,
5,
1
 
4.
Rocke
and
Lorenzato,
1995:
Rocke,
D.
M.
and
Lorenzato,
S.
Technometrics
1995,
37,
176
 
184.

Appendix
A:
Definitions,
Acronyms,
and
Abbreviations
Used
in
This
Document
AAMA
 
American
Automobile
Manufacturers
Association
ACS
 
American
Chemical
Society
AOAC
 
Association
of
Official
Analytical
Chemists
(
now
AOACInternational
APHA
 
American
Public
Health
Association
ASTM
 
American
Society
for
Testing
and
Materials
(
now
ASTM
International)
ATP
 
Alternate
Test
Procedure
AWWA
 
American
Water
Works
Association
CBI
 
confidential
business
information
CFR
 
Code
of
Federal
Regulations
CRV
 
critical
value
CWA
 
Clean
Water
Act
 
Federal
Water
Pollution
Control
Act
Amendments
(
33
U.
S.
C.
1251
et
seq.)
EPA
 
Environmental
Protection
Agency
EPRI
 
Electric
Power
Research
Institute
FR
 
Federal
Register
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12,
2003
/
Proposed
Rules
IDE
 
interlaboratory
detection
estimate
IIAG
 
Inter­
Industry
Analytical
Group
IQE
 
interlaboratory
quantitation
estimate
ISO
 
International
Organization
for
Standardization
IUPAC
 
International
Union
of
Pure
and
Applied
Chemistry
LOD
 
limit
of
detection
LOQ
 
limit
of
quantitation
MDL
 
method
detection
limit
MDV
 
minimum
detectable
value
ML
 
minimum
level
of
quantitation
NBS
 
National
Bureau
of
Standards
(
now
NIST)
NIST
 
National
Institute
of
Standards
and
Technology
(
formerly
NBS)
NPDES
 
National
pollutant
discharge
elimination
system
NTTAA
 
National
Technology
Transfer
and
Advancement
Act
OMB
 
Office
of
Management
and
Budget
POTW
 
Publicly­
owned
treatment
works
RFA
 
Regulatory
Flexibility
Act
SBREFA
 
Small
Business
Regulatory
Enforcement
Fairness
Act
SCC
 
Sample
Control
Center
TSD
 
technical
support
document
UMRA
 
Unfunded
Mandates
Reform
Act
USATHAMA
 
U.
S.
Army
Toxic
and
Hazardous
Materials
Agency
(
now
the
U.
S.
Army
Environmental
Center
[
USAEC])
U.
S.
C.
 
United
States
Code
WQBEL
 
water­
quality­
based
effluent
limit
WEF
 
Water
Environment
Federation
List
of
Subjects
at
40
CFR
Part
136
Environmental
protection,
Reporting
and
recordkeeping
requirements,
Water
pollution
control.

Dated:
February
28,
2003.
Christine
Todd
Whitman,
Administrator.

For
the
reasons
set
out
in
the
preamble,
title
40,
chapter
I
of
the
Code
of
Federal
Regulations,
is
proposed
to
be
amended
as
follows:

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

Authority:
Secs.
301,
304(
h),
307,
and
501(
a),
Pub.
L.
95
 
217,
91
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
136.2
is
amended
by
revising
paragraph
(
f)
and
adding
paragraph
(
g)
to
read
as
follows:

§
136.2
Definitions.

*
*
*
*
*
(
f)
Detection
limit
means
the
method
detection
limit
(
MDL),
as
determined
by
the
procedure
set
forth
at
Appendix
B
of
this
part.
The
MDL
is
an
estimate
of
the
measured
concentration
at
which
there
is
99%
confidence
that
a
given
analyte
is
present
in
a
given
sample
matrix.
(
g)
Minimum
level
of
quantitation
(
ML)
means
the
lowest
level
at
which
the
entire
analytical
system
gives
a
recognizable
signal
and
acceptable
calibration
point
for
the
analyte,
as
determined
by
the
procedure
set
forth
at
Appendix
B
of
this
part.
The
ML
represents
the
lowest
concentration
at
which
an
analyte
can
be
measured
with
a
known
level
of
confidence.
3.
Appendix
B
of
part
136
is
revised
to
read
as
follows:

Appendix
B
to
Part
136
A.
Definition
and
Procedure
for
the
Determination
of
the
Method
Detection
Limit
 
Revision
2
1.0
Definition
The
method
detection
limit
(
MDL)
is
an
estimate
of
the
measured
concentration
at
which
there
is
99%
confidence
that
a
given
analyte
is
present
in
a
given
sample
matrix.
The
MDL
is
the
concentration
at
which
a
decision
is
made
regarding
whether
an
analyte
is
detected
by
a
given
analytical
method.
The
MDL
is
calculated
from
replicate
analyses
of
a
matrix
containing
the
analyte
and
is
functionally
analogous
to
the
``
critical
value''
described
by
Currie
(
1968,
1995)
and
the
Limit
of
Detection
(
LOD)
described
by
the
American
Chemical
Society
(
Keith
et
al.,
1980,
McDougal
et
al.,
1983).

2.0
Scope
and
Application
2.1
This
procedure
is
for
the
determination
of
an
MDL
for
a
given
analyte
(
parameter)
in
a
given
matrix
(
the
component
or
substrate
that
contains
the
analyte)
using
a
given
test
procedure
(
analytical
method).
It
is
applicable
to
a
wide
variety
of
analytes,
matrices,
and
instruments,
and
to
a
broad
variety
of
physical
and
chemical
analytical
methods,
with
some
exceptions
(
e.
g.,
pH,
temperature).
This
procedure
is
intended
for
use
in
EPA's
Clean
Water
Act
(
CWA)
programs.
An
alternative
procedure
may
be
used
(
e.
g.,
from
a
voluntary
consensus
standards
body)
to
establish
the
sensitivity
of
an
analytical
method,
provided
the
resulting
detection
limit
meets
the
sensitivity
needs
for
the
specific
application.
2.2
This
procedure
requires
a
complete,
specific,
and
well­
defined
analytical
method.
It
is
essential
that
all
sample
processing
steps
of
the
analytical
method
that
are
applied
to
routine
analyses
be
included
in
determination
of
an
MDL.
2.3
This
procedure
may
be
used
for
a
variety
of
applications,
including,
but
not
limited
to:
2.3.1
Demonstrating
laboratory
capability
with
a
particular
method.
A
laboratory
using
this
procedure
to
demonstrate
capability
with
a
particular
method
is
not
required
to
perform
the
iterative
verification
of
the
MDL
(
section
4.8)
if
the
laboratory­
determined
MDL
is
less
than
or
equal
to
either
the
MDL
in
the
method,
the
MDL
required
to
support
a
regulation,
or
the
objectives
of
a
study
(
see
section
4.8.5).
2.3.2
Monitoring
trends
in
laboratory
performance.
When
used
in
this
manner,
the
MDL
for
a
given
analyte
measured
using
a
given
analytical
method
may
vary
as
a
function
of
laboratory
experience
and
the
matrix
tested.
2.3.3
Characterizing
method
sensitivity
in
a
particular
matrix.
An
MDL
is
typically
determined
in
a
reference
matrix.
However,
it
also
may
be
determined
in
a
real­
world
matrix
to
verify
that
the
target
MDL
can
be
achieved
in
that
matrix.
2.3.3.1
If
the
MDL
required
for
a
specific
application
can
be
achieved
in
a
real­
world
matrix,
that
MDL
may
be
used
in
lieu
of
a
reference­
matrix
MDL,
and
iteration
(
section
4.8)
is
not
necessary.
2.3.3.2
If
the
MDL
needed
for
a
specific
application
cannot
be
achieved
in
the
realworld
matrix
(
i.
e.,
if
the
purpose
of
the
MDL
study
is
to
demonstrate
the
effects
of
matrix
interferences
in
a
real
world
sample),
the
laboratory
must
(
1)
perform
an
MDL
study
in
a
reference
matrix
to
demonstrate
the
laboratory's
ability
to
apply
the
method
in
the
absence
of
interferences,
and
(
2)
verify
the
matrix­
specific
MDL
through
the
iterative
procedure
given
in
section
4.8.
2.3.3.3
Refer
to
section
4.2
for
additional
information
concerning
the
selection
of
test
matrices.
2.3.4
Establishing
an
MDL
for
a
new
or
revised
method
for
nationwide
use.
When
the
procedure
is
used
to
establish
an
MDL
for
a
new
or
revised
method,
the
MDL
should
be
derived
from
data
obtained
from
multiple
laboratories.
Organizations
developing
or
revising
methods
must
document
and
make
available
the
data
and
procedures
used
to
establish
an
MDL
to
obtain
approval
for
use
under
Clean
Water
Act
programs.

3.0
Summary
of
the
Procedure
3.1
The
procedural
steps
required
for
determining
an
MDL
vary
with
the
intended
application
of
the
MDL.
However,
regardless
of
the
intended
application,
all
MDL
determinations
must
include
the
following
steps:
(
a)
Estimating
the
detection
limit
of
the
method
as
practiced,
(
b)
Selecting
the
appropriate
matrix
to
be
used
in
the
determination,
(
c)
Selecting
the
appropriate
test
concentration,
(
d)
Preparing
and
analyzing
a
minimum
of
seven
replicate
aliquots
of
a
blank
or
spiked
matrix,
(
e)
Calculating
the
mean
concentration
of
the
analyte,
the
standard
deviation
of
that
mean,
and
the
MDL,
using
the
formula
provided
in
this
procedure,
(
f)
Comparing
the
calculated
MDL
to
a
method­
specified
MDL,
relevant
regulatory
requirements,
or
project­
specific
objectives,
as
appropriate.
3.2
When
developing
MDLs
for
new
or
revised
methods,
or
developing
matrixspecific
MDLs
for
nationwide
use,
the
procedure
also
may
include:
(
a)
Conducting
an
optional
pre­
test
using
fewer
replicates
to
verify
that
an
appropriate
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Proposed
Rules
concentration
was
selected
to
perform
the
MDL
test,
(
b)
Conducting
an
iterative
procedure
involving
analyses
of
additional
replicates
to
verify
the
reasonableness
of
the
MDL
(
required
for
method
development),
(
c)
Determining
the
MDL
in
additional
relevant
matrices
or
in
multiple
laboratories.

4.0
Procedure
4.1
Estimate
the
detection
limit
of
the
method
If
the
purpose
of
determining
the
MDL
is
to
verify
laboratory
performance
using
a
specific
method
or
to
determine
the
MDL
in
a
specific
matrix,
the
laboratory
should
use
the
MDL
published
in
the
method
as
the
initial
estimate.
If
the
MDL
is
being
determined
for
other
reasons
(
e.
g.,
method
development),
the
experience
of
the
laboratory
is
important
to
properly
estimate
the
detection
limit.
The
laboratory
must
include
at
least
one
of
the
following
considerations
in
producing
this
initial
estimate:
4.1.1
The
concentration
of
analyte
that
produces
an
instrument
signal/
noise
in
the
range
of
2.5
to
5
for
those
instances
in
which
an
instrument
is
used
for
the
determination.
4.1.2
The
concentration
approximately
equal
to
three
times
the
standard
deviation
of
replicate
measurements
of
the
analyte
in
a
blank.
If
analysis
of
the
blank
produces
no
response
(
zero),
use
the
concentration
approximately
equal
to
three
times
the
standard
deviation
of
replicate
measurements
at
the
lowest
concentration
that
always
produces
a
response.
4.1.3
A
concentration
in
the
region
of
constant
or
effectively
constant
standard
deviation
at
low
concentrations.
This
assumes
that
the
model
of
Glaser
et
al.
(
1981),
which
includes
a
low
concentration
region
where
the
standard
deviation
of
the
measurement
error
is
constant
or
effectively
constant,
is
suitable
to
describe
the
measurement
process
for
the
analytical
method
under
consideration.
4.1.4
The
lowest
concentration
that
can
be
detected
by
analyzing
samples
containing
successively
lower
concentrations
of
the
analyte.
4.2
Select
the
matrix
to
be
used
to
develop
the
MDL.
The
MDL
is
typically
determined
in
a
reference
matrix.
However,
it
may
be
determined
in
a
real­
world
matrix
to
verify
that
the
MDL
required
for
a
specific
application
can
be
achieved
in
that
matrix.
4.2.1
Reference
Matrix
The
most
common
reference
matrix
is
reagent
water.
Reagent
water
is
defined
as
water
in
which
the
analyte
and
interferences
are
not
detected
at
the
MDL
or,
if
this
is
the
initial
estimate,
detected
at
the
detection
limit
estimated
in
section
4.1.
An
interference
is
defined
as
a
systematic
error
in
the
measured
analytical
signal
caused
by
the
presence
of
a
substance
other
than
the
analyte.
Other
common
reference
matrices
are
sand
as
a
reference
matrix
for
soils,
sediments,
and
other
solid
samples;
and
corn
oil
as
a
reference
matrix
for
tissue
samples.
After
selecting
the
reference
matrix
to
be
tested,
proceed
to
section
4.3.
4.2.2
Matrices
other
than
a
reference
matrix
4.2.2.1
If
the
MDL
determined
in
a
matrix
other
than
a
reference
matrix
is
sufficient
to
meet
requirements
of
the
specific
application
(
e.
g.,
the
laboratory
is
able
to
meet
the
MDL
required
for
compliance
monitoring
or
published
in
the
method),
it
is
not
necessary
to
determine
the
MDL
in
a
reference
matrix.
4.2.2.2
If
the
purpose
of
a
matrix­
specific
MDL
is
to
determine
the
effects
of
matrix
interferences
in
a
real­
world
sample,
the
laboratory
also
must
determine
the
MDL
in
a
reference
matrix
to
demonstrate
the
laboratory's
ability
to
apply
the
method
in
the
absence
of
interferences.
Note
to
Section
4.2.2.2:
A
laboratory
seeking
to
develop
a
matrix­
specific
MDL
for
a
specific
method
must
use
the
same
cleanup
steps
that
will
be
used
for
analysis
of
samples.
4.3
Establish
the
test
concentration
range
and
prepare
test
samples
Establish
the
test
concentration
range
per
section
4.3.1.
Prepare
the
test
samples
from
a
reference
matrix
per
section
4.3.2,
or
from
an
alternative
matrix
per
section
4.3.3.
Prepare
a
sufficient
quantity
of
the
matrix
to
provide
samples
for
a
minimum
of
seven
analyses.
Note
to
Section
4.3:
For
analytes
for
which
a
single­
volume
(
bulk)
sample
or
spiked
single­
volume
sample
would
result
in
nonhomogenous
replicates
(
e.
g.,
for
determination
of
``
oil
and
grease''),
or
for
which
preparation
of
a
spiked
single­
volume
sample
is
impractical,
a
minimum
of
seven
individual
aliquots
should
be
prepared
at
the
test
concentration.
4.3.1
Establish
the
test
concentration
range
as
follows.
4.3.1.1
If
verifying
an
MDL
that
is
published
in
an
analytical
method,
the
test
concentration
should
be
no
more
than
five
times
the
published
MDL.
4.3.1.2
If
verifying
an
MDL
required
to
support
a
regulatory
objective
or
the
objective
of
a
specific
study
or
program,
the
test
concentration
should
be
no
more
than
one
third
the
compliance
or
target
limit.
4.3.1.3
If
performing
an
MDL
study
for
a
new
or
revised
method,
the
test
concentration
should
be
no
more
than
five
times
the
detection
limit
estimated
in
section
4.1.
4.3.1.4
If
performing
an
iteration
(
see
section
4.8),
the
test
concentration
should
be
no
more
than
five
times
the
MDL
determined
in
the
most
recent
iteration.
4.3.2
Preparing
test
samples
from
a
reference
matrix
If
a
blank
sample
produces
an
acceptable
signal
(
see
section
4.3.2),
spiking
is
not
required;
otherwise,
spike
the
reference
matrix
at
the
concentration
established
in
section
4.3.1.
Proceed
to
section
4.4.
Note
to
Section
4.3.2:
The
laboratory
must
ensure
that
the
levels
in
blanks
are
not
too
high.
Otherwise,
the
resulting
MDL
produced
may
be
artificially
biased.
For
a
spiked
sample,
the
concentration
of
the
contaminant
in
the
blank
should
not
be
a
significant
portion
of
the
total
concentration
since
this
also
could
result
in
an
artificial
bias
for
the
MDL.
It
is
important
to
spike
the
analyte
at
the
proper
concentration
(
section
4.3)
to
ensure
the
MDL
is
determined
accurately.
4.3.3
Preparing
test
samples
from
a
matrix
other
than
a
reference
matrix
Analyze
three
aliquots
of
the
sample
matrix
to
characterize
the
concentration
of
the
target
analyte(
s)
present
in
the
matrix.
4.3.3.1
If
the
average
measured
concentration
of
the
analyte
in
the
matrix
is
less
than
five
times
the
concentration
established
in
section
4.3.1,
proceed
to
section
4.4.
4.3.3.2
If
the
average
measured
concentration
of
the
analyte
in
the
matrix
is
less
than
the
concentration
range
established
in
section
4.3.1,
spike
the
matrix
to
bring
the
concentration
of
the
analyte
to
the
established
concentration
range
and
proceed
to
section
4.4.
4.3.3.3
If
the
average
measured
concentration
of
the
analyte
in
the
matrix
is
greater
than
the
concentration
range
established
in
section
4.3.1,
reduce
the
concentration
of
the
analyte
to
the
established
concentration
range,
using
one
of
the
following
techniques
before
proceeding
to
section
4.4:
4.3.3.3.1
Selectively
remove
the
analyte
from
the
matrix.
4.3.3.3.2
Obtain
another
matrix
with
a
lower
concentration
of
the
analyte.
4.3.3.3.3
Dilute
a
sample
of
the
matrix
with
the
appropriate
reference
matrix.
For
example,
if
the
matrix
is
aqueous,
dilute
the
sample
with
reagent
water.
Note
to
Section
4.3.3.3.3:
Dilution
should
be
used
only
if
the
analyte
cannot
be
selectively
removed
(
3.3.3.1)
or
if
another
matrix
with
a
lower
analyte
concentration
cannot
be
obtained
(
3.3.3.2)
because
dilution
of
the
sample
has
the
potential
to
dilute
any
interferences
present.
4.4
Perform
the
analyses
4.4.1
The
analyses
in
section
4.4.3
(
optional
pre­
test
of
estimated
detection
limit)
and
4.2
(
MDL
analyses)
must
be
performed
using
all
of
the
routinely
employed
calibration,
sample
handling,
processing,
and
result
calculations
specified
in
the
analytical
method.
For
example,
many
methods
contain
multiple
sample
cleanup
options;
any
and
all
cleanup
options
routinely
used
to
analyze
a
sample
must
be
used
when
analyzing
the
replicate
samples
prepared
in
section
4.3.
4.4.2
Similarly,
if
the
analytical
method
employs
recovery­
correction
or
blankcorrection
procedures
for
calculating
results,
those
procedures
must
be
used
when
calculating
results
of
an
analysis
of
each
aliquot.
If
a
recovery­
or
blank­
correction
procedure
is
not
specified
in
the
test
method,
such
correction
must
not
be
used.
4.4.3
Optional
pre­
test
It
may
be
economically
and
technically
desirable
to
evaluate
the
estimate
of
the
detection
limit
(
section
4.1)
before
proceeding
with
determination
of
the
MDL
in
section
4.5.
This
pre­
test
attempts
to
ensure
that
the
MDL
study
is
being
conducted
at
the
correct
concentration
to
prevent
repeating
the
entire
study;
it
may
be
particularly
useful
when
the
analytical
costs
are
high.
To
evaluate
the
estimated
detection
limit,
proceed
as
follows:
4.4.3.1
Process
three
aliquots
of
the
test
sample
prepared
in
section
4.3
through
the
entire
method,
per
section
4.5.
4.4.3.2
Calculate
the
standard
deviation
of
results
for
the
three
aliquots
as
follows:

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/
Vol.
68,
No.
48
/
Wednesday,
March
12,
2003
/
Proposed
Rules
s
X
X
n
i
i
n
=
 
(
)

 
=
 
2
1
1
Where:
Xi
=
a
result
in
the
method
reporting
units
obtained
from
analysis
of
a
sample
aliquot,
i=
1
to
3
X
¯
=
mean
of
the
three
results,
and
n
=
number
of
sample
aliquots
(
3
in
this
case)
4.4.3.3
Calculate
a
preliminary
MDL
as
follows:
Preliminary
MDL
=
6.96s
Where:
6.96
=
Student's
t­
value
appropriate
for
a
99%
confidence
level
and
two
degrees
of
freedom
s
=
standard
deviation
of
the
results
of
analyses
of
the
three
replicates
from
section
4.4.3.2
4.4.3.4
If
the
preliminary
MDL
is
in
the
range
of
0.2
 
1.0
times
the
concentration
in
the
spiked
sample
(
section
4.3),
analyze
a
minimum
of
four
additional
aliquots
and
proceed
using
the
procedure
in
section
4.5.
Use
all
seven
measurements
for
calculation
of
the
MDL.
Otherwise,
produce
a
new
bulk
sample
per
section
4.3,
with
the
analyte
at
the
concentration
of
the
preliminary
MDL
and
either
repeat
section
4.4.3,
or
proceed
to
section
4.5
for
determination
of
the
MDL.
4.5
MDL
determination
4.5.1
Process
at
least
seven
aliquots
of
the
test
sample
prepared
in
section
4.4
or
section
4.4.3
through
the
entire
analytical
method.
4.5.2
Make
all
computations
as
specified
in
the
method,
with
final
results
in
the
method­
specified
reporting
units.
4.5.3
To
obtain
a
valid
MDL,
all
of
the
analytical
results
must
be
positive
numbers.
If
any
of
the
results
are
negative
or
zero,
increase
the
test
concentration
(
per
section
4.3)
and
repeat
the
MDL
procedure.
4.5.4
If
more
than
seven
aliquots
are
prepared
and
analyzed,
the
results
from
all
the
aliquots
must
be
used
to
calculate
the
MDL,
except
as
described
in
section
4.9.
4.6
Calculate
the
standard
deviation,
s,
as
follows:

s
X
X
n
i
i
n
=
 
(
)

 
=
 
2
1
1
Where:
Xi
=
a
result,
in
the
method
reporting
units,
obtained
from
analysis
of
a
sample
aliquot,
i=
1
to
n
X
¯
=
mean
of
the
results,
and
n
=
number
of
sample
aliquots
Note
to
Section
4.6:
When
using
a
program
such
as
a
spreadsheet
to
calculate
the
standard
deviation
(
s),
make
certain
that
the
sample
standard
deviation,
which
uses
(
n
¥
1)
in
the
denominator,
is
calculated,
rather
than
the
population
standard
deviation
(
s),
which
uses
n
in
the
denominator.

4.7
Calculate
the
MDL
The
MDL
is
t
n
calculated
as:
MDL
=
s
×
 
 
=
(
)
1
1
0
99
,
.
 
Where:
s
=
standard
deviation
of
the
results
calculated
in
section
4.6
t(
n
¥
1,
1
¥
a=
0.99)
=
Students'
t­
value
appropriate
for
a
99%
confidence
level
and
(
n
¥
1)
degrees
of
freedom,
from
the
table
below.

TABLE
OF
STUDENT'S
t­
VALUES
AT
THE
99%
CONFIDENCE
LEVEL
Number
of
replicates
for
Degrees
of
freedom
(
df)
t(
n
¥
1,

1
¥
a=
0.99)
Singles
MDL
(
df
=
n
¥
1)
Iterative
MDL
(
df
=
n
¥
2)

7
...............................................................................................................................................................
N/
A
6
3.143
8
...............................................................................................................................................................
N/
A
7
2.998
9
...............................................................................................................................................................
N/
A
8
2.896
10
.............................................................................................................................................................
N/
A
9
2.821
11
.............................................................................................................................................................
N/
A
10
2.764
12
.............................................................................................................................................................
N/
A
11
2.718
13
.............................................................................................................................................................
14
12
2.681
14
.............................................................................................................................................................
15
13
2.650
15
.............................................................................................................................................................
16
14
2.624
16
.............................................................................................................................................................
17
15
2.602
17
.............................................................................................................................................................
18
16
2.583
18
.............................................................................................................................................................
19
17
2.567
19
.............................................................................................................................................................
20
18
2.552
Note
to
Section
4.7:
Degrees
of
freedom
=
(
n
¥
1)
if
a
single
MDL
study
is
performed.
If
an
iterative
MDL
study
is
performed,
degrees
of
freedom
=
(
nh
+
n1
¥
2),
as
described
in
section
4.8;
N/
A
indicates
that
the
number
of
degrees
of
freedom
in
this
row
does
not
apply
to
an
iterative
MDL
study.
4.8
Iterate
and
verify
the
reasonableness
of
the
MDL
When
developing
an
MDL
for
a
new
or
revised
method,
or
when
developing
a
matrix­
specific
MDL,
the
MDL
procedure
must
be
iterated
and
the
reasonableness
of
the
MDL
determined
using
an
F­
test,
as
described
in
sections
4.8.1
through
4.8.4.
When
verifying
a
method­,
matrix­,
program­,
or
study­
specific
MDL,
the
MDL
is
determined
as
described
in
section
4.8.5
and
iteration
may
not
be
necessary.
4.8.1
Iteration
When
developing
an
MDL
for
a
new
or
revised
method,
the
spiking,
analysis,
and
calculation
steps
(
sections
4.3
to
4.6)
must
be
repeated
using
a
spike
at
no
more
than
five
times
the
MDL
determined
initially
or
in
the
most
recent
iteration,
to
confirm
the
reasonableness
of
the
MDL.
4.8.2
Once
the
iteration
is
complete
(
i.
e.,
two
successive
MDL
estimates
have
been
produced),
calculate
the
F­
ratio
(
F)
as:

F
s
n
s
n
h
h
l
l
=
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2
2
1
1
Where:
sh
2
=
variance
estimate
from
the
higher
spike
concentration
sl
2
=
variance
estimate
from
the
lower
spike
concentration
nh
=
number
of
observations
at
the
higher
concentration
nl
=
number
of
observations
at
the
lower
concentration
4.8.3
For
seven
replicates
at
each
concentration,
the
90th
percentile
of
the
distribution
of
the
F­
statistic
is
3.055.
4.8.3.1
If
seven
replicates
were
analyzed
at
each
spike
concentration
and
F
>
3.055,
the
two
variances
are
different
and
the
MDL
determined
at
the
higher
spike
concentration
is
not
a
reasonable
estimate.
In
this
case,
return
to
section
4.3
and
produce
another
sample
at
a
test
concentration
below
the
higher
of
the
two
previous
iterations,
analyze
a
minimum
of
seven
aliquots,
calculate
the
MDL,
and
repeat
the
F­
test
in
section
4.8.2.
4.8.3.2
If
F
 
3.055
for
seven
replicates
at
each
concentration,
the
two
variances
are
not
different.
Proceed
to
section
4.8.4.
Note
to
Section
4.8.3.2:
If
more
than
seven
replicates
are
used,
the
appropriate
F­
statistic
is
determined
from
the
table
below.

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Register
/
Vol.
68,
No.
48
/
Wednesday,
March
12,
2003
/
Proposed
Rules
TABLE
OF
F­
STATISTIC
VALUES
F­
statistic
6
7
8
9
6
.......................................................................................................................................
3.055
3.014
2.983
2.958
7
.......................................................................................................................................
2.827
2.785
2.752
2.725
8
.......................................................................................................................................
2.668
2.624
2.589
2.561
9
.......................................................................................................................................
2.551
2.505
2.469
2.440
4.8.4
When
the
process
has
been
iterated
and
the
results
pass
the
F­
test
in
section
4.8.3,
the
final
MDL
is
calculated
by
pooling
the
results
from
the
two
iterations
that
passed
the
F­
test.
The
pooled
standard
deviation
is
calculated
as:

s
n
s
n
s
n
n
pooled
h
h
l
l
h
l
=
 
(
)(
)+
 
(
)(
)
+
 
(
)
1
1
2
2
2
Where:
(
sh)
2
=
variance
estimate
from
the
higher
spike
concentration
(
sl)
2
=
variance
estimate
from
the
lower
spike
concentration
nh
=
number
of
sample
aliquots
used
for
the
higher
spike
concentration
nl
=
number
of
sample
aliquots
used
for
the
lower
spike
concentration
4.8.5
The
pooled
MDL
is
calculated
using
the
pooled
standard
deviation
and
the
Student's
t­
value
for
(
nh
+
nl
¥
2)
degrees
of
freedom
(
e.
g.,
12
degrees
of
freedom
for
two
iterations
with
seven
aliquots
each).

MDL
s
t
pooled
pooled
n
n
h
l
=
×
+
 
 
=
(
)
2
099
,
.
1
 
Where:
Spooled
=
pooled
standard
deviation
of
the
results
t(
nh
 
n1­
2,
1­
a
=
0.99)
=
Student's
t­
value
appropriate
for
a
99%
confidence
level
and
(
nh+
nl)
aliquots
For
12
degrees
of
freedom,
the
t­
value
is
2.681.
If
more
than
seven
replicates
were
used
for
either
iteration,
the
appropriate
tvalue
must
be
determined
from
the
table
given
in
section
4.7.
4.8.5
When
verifying
a
method­,
matrix­,
program­,
or
study­
specific
MDL,
the
determined
MDL
is
compared
to
the
methodspecified
MDL,
the
MDL
required
to
support
a
regulatory
objective,
or
the
MDL
required
to
support
an
objective
of
a
specific
study
or
program.
If
the
required
MDL
is
not
met
for
the
analyte,
make
sure
that
all
instrumentation
and
technical
aspects
of
the
process
(
reagent
concentrations,
temperature,
clean
glassware,
proper
dilutions,
etc.)
are
checked
and
assessed
to
be
working
properly
before
a
repeat
of
the
analyses.
If
the
second
attempt
fails,
iteration
at
a
more
appropriate
spiking
level
for
that
analyte
is
necessary
until
the
requirement
is
met.
If
the
regulatory,
study,
or
program
objective
is
not
known,
the
MDL
is
verified
if
the
determined
MDL
is
less
than
or
equal
to
the
methodspecified
MDL.
4.9
Suspected
Outliers
4.9.1
Results
associated
with
a
known,
spurious
error
that
occurred
during
analysis
should
be
discarded,
or
where
appropriate,
corrected.
Spurious
errors
include
those
that
arise
through
human
error
or
instrument
malfunction,
such
as
transposing
digits
in
a
number
while
recording
data,
arithmetical
errors
when
calculating
results,
doublespiking
of
an
aliquot,
or
the
presence
of
an
air
bubble
lodged
in
a
spectrophotometer
flow­
through
cell.
Recording
or
arithmetical
errors
can
and
should
be
corrected,
and
the
corrective
actions
documented
prior
to
use
of
results.
Results
associated
with
spurious
errors
that
cannot
be
corrected
will
invalidate
the
measurement
and
should
not
be
incorporated
into
the
MDL
determination.
4.9.2
If
random
or
spurious
errors
are
suspected,
it
may
be
appropriate
to
apply
a
statistically
accepted
analysis
of
outliers,
such
as
Grubbs
test
described
below.
Any
outlying
result
should
be
considered
with
care
to
identify
potential
causes.
It
is
generally
not
an
accepted
practice
to
reject
a
value
purely
on
statistical
grounds.
Therefore,
EPA
recommends
that
when
the
cause
of
a
potential
outlier
cannot
be
attributed
to
spurious
causes,
the
MDL
test
be
repeated
for
the
analyte(
s)
in
which
such
an
outlier
occurs.
Note
to
Section
4.9.2:
If
more
than
seven
aliquots
are
prepared
and
analyzed,
results
from
all
aliquots
must
be
used
in
the
MDL
determination
unless
they
have
been
determined
to
be
outliers
as
described
above.
Given
the
small
number
of
replicates
typically
used
to
determine
the
MDL,
it
is
inappropriate
to
use
a
data
set
that
contains
more
than
one
statistical
outlier.
4.9.3
The
use
of
Grubbs
test
for
outliers
is
described
below,
followed
by
an
example
(
section
4.9.4).
4.9.3.1
Rank
the
n
observed
data
points
in
the
order
of
increasing
numerical
value:
X1
 
X2
 ... 
Xn
4.9.3.2
Using
the
mean,
X
¯
,
and
standard
deviation,
s,
from
section
4.6,
calculate:

T
X
X
s
X
X
s
l
n
=
 
(
)
=
 
(
)
1
and
Tn
Where:
X1
=
lowest
observed
value
of
X
Xn
=
highest
observed
value
of
X
4.9.3.3
Choose
the
larger
of
T1
and
Tn.
4.9.3.4
Compare
the
larger
calculated
value
of
T
(
e.
g.,
T1
or
Tn)
with
the
critical
value
appropriate
for
the
number
of
observations
(
n)
from
the
table
below.
If
T
is
larger
than
the
critical
value
in
the
table,
then
the
smallest
(
when
testing
T1)
or
largest
(
when
testing
Tn)
observed
data
point
is
considered
to
be
an
outlier
with
95%
confidence.
TABLE
OF
CRITICAL
VALUES
FOR
T
IN
THE
GRUBBS
TEST
Number
of
data
points
(
n)
Critical
values
for
T
7
............................................
2.020
8
............................................
2.126
9
............................................
2.215
10
..........................................
2.290
11
..........................................
2.355
12
..........................................
2.412
13
..........................................
2.462
14
..........................................
2.507
15
..........................................
2.549
4.9.4
Example
application
of
the
outlier
test
4.9.4.1
Consider
the
following
ranked
data
set
with
seven
observations:
0.0449,
0.0458,
0.0462,
0.0469,
0.0471,
0.0475,
and
0.0508.
4.9.4.2
Its
mean,
X
¯
,
is
0.0470,
and
its
standard
deviation,
s,
is
0.0019.
4.9.4.3
Calculate:
T1
=
(
0.0470
¥
0.0449)/
0.0019
=
1.132
and
Tn
=
(
0.0508
¥
0.0470)/
0.0019
=
2.007
4.9.4.4
Select
the
larger
value:
T
=
max{
1.132,
2.007}
=
2.007
4.9.4.5
Compare
T
with
the
corresponding
critical
value
in
the
second
line
of
the
table
above,
where
n=
7
and
the
critical
value
of
T
=
2.020.
Since
the
calculated
value
of
T,
2.007,
is
not
larger
than
the
critical
value
in
the
table,
2.020,
there
is
insufficient
evidence
to
conclude
that
any
of
the
observed
data
points
is
an
outlier,
and
the
MDL
would
be
calculated
from
all
seven
results.

5.0
References
5.1
Currie,
Lloyd
A.
(
1968),
Limits
for
Quantitative
Detection
and
Quantitative
Determination,
Analytical
Chemistry
40:
586
 
593.
5.2
Currie,
Lloyd
A.
(
1995),
Nomenclature
in
Evaluation
of
Analytical
Methods
including
Detection
and
Quantification
Capabilities,
Pure
and
Appl.
Chem.
67:
10,
1699
 
1722.
5.3
Glaser,
J.
A.,
D.
L.
Foerst,
J.
D.
McKee,
S.
A.
Quave
and
W.
L.
Budde
(
1981),
Trace
Analyses
for
Wastewaters,
Environ.
Sci.
Technol.,
15:
1426.
5.4
Keith,
Lawrence
H.,
et
al.
(
1983),
Principles
of
Environmental
Analysis,
Analytical
Chemistry
55:
14,
2210
 
2218.
5.5
McDougal,
Daniel,
et
al.
(
1980),
Guidelines
for
Data
Acquisition
and
Data
Quality
Evaluation
in
Environmental
Chemistry,
Analytical
Chemistry
52:
14,
2242
 
2249.

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11790
Federal
Register
/
Vol.
68,
No.
48
/
Wednesday,
March
12,
2003
/
Proposed
Rules
B.
Definition
and
Procedure
for
the
Determination
of
the
Minimum
Level
of
Quantitation
(
ML)

1.0
Definition
The
minimum
level
of
quantitation
(
ML)
is
the
lowest
level
at
which
the
entire
analytical
system
gives
a
recognizable
signal
and
acceptable
calibration
point
for
the
analyte.
The
ML
represents
the
lowest
concentration
at
which
an
analyte
can
be
measured
with
a
known
level
of
confidence.
It
may
be
equivalent
to
the
concentration
of
the
lowest
calibration
standard,
assuming
that
all
method­
specified
sample
weights,
volumes,
and
cleanup
procedures
have
been
employed.
It
is
functionally
analogous
to
the
``
determination
limit''
described
by
Currie
(
1968)
and
the
Limit
of
Quantification
(
LOQ)
described
by
the
American
Chemical
Society
(
Keith
et
al.,
1980,
McDougal
et
al.,
1983)
and
Currie
(
1995).
Note
to
Section
1.0:
The
ML
is
directed
at
obtaining
a
10%
relative
standard
deviation
for
determination
of
an
analyte
in
an
environmental
sample.
This
error
may
be
reduced
by
making
multiple
determinations
of
the
analyte
in
the
sample.

2.0
Scope
and
Application
2.1
The
ML
is
typically
established
by
the
organization
that
develops
or
modifies
an
analytical
test
method.
A
laboratory
that
employs
the
method
would
be
expected
to
include
calibration
standards
that
encompass
the
ML
when
it
calibrates
an
analytical
system,
unless
a
higher
quantitation
level
is
acceptable
for
a
specific
application.
If
an
ML
is
not
specified
in
a
method,
a
laboratory
may
use
the
ML
procedure
to
establish
the
lowest
calibration
point.
2.2
This
procedure
is
intended
for
use
in
EPA's
Clean
Water
Act
(
CWA)
programs.
An
alternative
procedure
may
be
used
(
e.
g.,
from
a
voluntary
consensus
standards
body)
to
establish
the
sensitivity
of
an
analytical
method
provided
the
resulting
quantitation
limit
meets
the
sensitivity
needs
(
i.
e.,
data
quality
objective)
for
the
specific
application.
2.3
Laboratories
are
encouraged,
but
not
required,
to
periodically
demonstrate
recovery
of
the
target
analyte
near
the
published
ML
or
laboratory­
established
ML
by
preparing
a
reference
matrix
sample
spiked
at
the
ML
and
analyzing
it
using
all
sample
handling
and
processing
steps
described
in
the
method.
If
the
method
does
not
provide
acceptance
criteria
for
such
an
ML
standard,
the
laboratory
can
make
an
assessment
of
whether
acceptance
criteria
for
other
spiked
reference
matrix
samples
(
e.
g.,
laboratory
control
samples,
laboratory
fortified
blanks,
ongoing
precision
and
recovery
samples,
etc.)
are
appropriate
to
evaluate
analyte
recovery
at
the
ML.
Alternatively,
the
laboratory
may
develop
its
own
acceptance
criteria
based
on
data
gathered
by
the
laboratory
over
time.

3.0
Procedure
3.1
The
ML
is
based
on
10
times
the
standard
deviation
of
the
results
of
replicate
analyses
of
a
matrix
containing
the
analyte.
The
method
detection
limit
(
MDL)
is
also
based
on
the
same
standard
deviation,
multiplied
by
the
Student's
t­
value
appropriate
for
a
99%
confidence
level
and
corresponding
degrees
of
freedom.
Because
the
standard
deviation
may
not
be
readily
available,
the
ML
is
often
calculated
as
a
factor
times
the
MDL.
3.1.1
Calculating
the
ML
based
on
MDL
study
data
When
available,
obtain
the
actual
standard
deviation
value
from
the
MDL
study
and
calculate
the
ML
directly,
as
10
times
the
standard
deviation.
If
an
iterative
MDL
study
is
performed,
calculate
the
MDL
as
10
times
the
pooled
standard
deviation.
3.1.2
Calculating
the
ML
based
on
the
MDL
Assuming
a
single
iteration
of
seven
replicates
is
used
to
determine
the
MDL,
the
number
of
degrees
of
freedom
is
6,
and
the
Student's
t­
value
is
3.143.
Therefore,
the
MDL
is:
MDL
=
3.143
×
s
and
the
ML
is:

ML
s
MDL
MDL
=
×
=
×
 
×
10
10
3143
318
.
.

3.1.3
If
the
MDL
is
calculated
from
other
than
seven
replicates
or
using
the
iterative
procedure,
the
factor
of
3.18
will
change,
and
the
table
below
is
used
to
establish
the
correct
multiplier.
For
example,
if
an
iterative
MDL
study
is
performed
consisting
of
exactly
7
replicates
in
each
iteration,
the
resulting
pooled
MDL
would
incorporate
12
degrees
of
freedom,
and
the
equation
for
the
ML
above
would
be
modified
accordingly,
using
a
multiplier
of
3.73.

TABLE
OF
STUDENT'S
t­
VALUES
AT
THE
99%
CONFIDENCE
LEVEL
AND
ML
MULTIPLIERS
Number
of
replicates
for
Degrees
of
freedom
(
df)
t(
n­
1,1­
a=
0.99)
ML
multiplier
Single
MDL
(
df=
n
¥
1)
Iterative
MDL
(
df=
n
¥
2)

7
.................................................................................................................
N/
A
6
3.143
3.18
8
.................................................................................................................
N/
A
7
2.998
3.34
9
.................................................................................................................
N/
A
8
2.896
3.45
10
...............................................................................................................
N/
A
9
2.821
3.54
11
...............................................................................................................
N/
A
10
2.764
3.62
12
...............................................................................................................
N/
A
11
2.718
3.68
13
...............................................................................................................
14
12
2.681
3.73
14
...............................................................................................................
15
13
2.650
3.77
15
...............................................................................................................
16
14
2.624
3.81
16
...............................................................................................................
17
15
2.602
3.84
17
...............................................................................................................
18
16
2.583
3.87
18
...............................................................................................................
19
17
2.567
3.90
19
...............................................................................................................
20
18
2.552
3.92
Note
to
Table:
Degrees
of
freedom
=
(
n
¥
1)
if
a
single
iteration
MDL
study
is
performed
and
(
nh
+
nl
¥
2)
if
an
iterative
MDL
study
is
performed;
N/
A
indicates
that
the
number
of
degrees
of
freedom
in
this
row
does
not
apply
to
an
iterative
MDL
study.

4.0
Rounding
The
ML
may
be
used
to
establish
the
lowest
calibration
point
for
the
analyte.
Therefore,
in
order
to
facilitate
the
preparation
of
calibration
standards
containing
the
analyte
without
undue
difficulty,
the
ML
may
be
rounded
to
the
nearest
multiple
of
1,
2,
or
5
×
10
n,
where
n
is
an
integer.

5.0
References
5.1
Currie,
Lloyd
A.
(
1968),
Limits
for
Quantitative
Detection
and
Quantitative
Determination,
Analytical
Chemistry
40:
586
 
593.
5.2
Currie,
Lloyd
A.
(
1995),
Nomenclature
in
Evaluation
of
Analytical
Methods
including
Detection
and
Quantification
Capabilities,
Pure
and
Appl.
Chem.
67:
10,
1699
 
1722.
5.3
Glaser,
J.
A.,
D.
L.
Foerst,
J.
D.
McKee,
S.
A.
Quave
and
W.
L.
Budde
(
1981),
Trace
Analyses
for
Wastewaters,
Environ.
Sci.
Technol.,
15:
1426.
5.4
Keith,
Lawrence
H.,
et
al.
(
1983),
Principles
of
Environmental
Analysis,
Analytical
Chemistry
55:
14,
2210
 
2218.
5.5
McDougal,
Daniel,
et
al.
(
1980),
Guidelines
for
Data
Acquisition
and
Data
Quality
Evaluation
in
Environmental
Chemistry,
Analytical
Chemistry
52:
14,
2242
 
2249.

[
FR
Doc.
03
 
5712
Filed
3
 
11
 
03;
8:
45
am]

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