Friday,

July
18,
2003
Part
VI
Environmental
Protection
Agency
National
Primary
Drinking
Water
Regulations;
Announcement
of
Completion
of
EPA's
Review
of
Existing
Drinking
Water
Standards;
Notice
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Friday,
July
18,
2003
/
Notices
ENVIRONMENTAL
PROTECTION
AGENCY
[
FRL
 
7529
 
1]

RIN
2040
 
AD67
National
Primary
Drinking
Water
Regulations;
Announcement
of
Completion
of
EPA's
Review
of
Existing
Drinking
Water
Standards
AGENCY:
Environmental
Protection
Agency.
ACTION:
Notice.

SUMMARY:
The
Safe
Drinking
Water
Act
(
SDWA)
requires
the
United
States
Environmental
Protection
Agency
(
EPA)
to
conduct
a
periodic
review
of
existing
National
Primary
Drinking
Water
Regulations
(
NPDWRs).
EPA
has
completed
its
review
of
69
NPDWRs
that
were
established
prior
to
1997,
including
68
chemical
NPDWRs
and
the
Total
Coliform
Rule
(
TCR).
The
intended
purpose
of
the
review
was
to
identify
those
NPDWRs
for
which
current
health
risk
assessments,
changes
in
technology,
and/
or
other
factors,
provide
a
health
or
technological
basis
to
support
a
regulatory
revision
that
will
maintain
or
improve
public
health
protection.
EPA
published
its
protocol
for
the
review
of
NPDWRs
and
its
preliminary
revise/
not
revise
decisions
for
the
69
NPDWRs
in
the
April
17,
2002,
edition
of
the
Federal
Register
(
67
FR
19030
(
USEPA,
2002g))
in
order
to
seek
comment
from
the
public.
Today's
action
briefly
describes
the
major
comments,
other
new
information,
and
EPA's
current
revise/
not
revise
decisions
for
the
69
NPDWRs.
ADDRESSES:
The
official
public
docket
for
this
action
is
located
at
EPA
West
Building,
Room
B102,
1301
Constitution
Avenue,
NW.,
Washington,
DC.
FOR
FURTHER
INFORMATION
CONTACT:
Contact:
Ken
Rotert,
(
202)
564
 
5280,
e­
mail:
rotert.
kenneth@
epa.
gov
for
inquiries
regarding
the
TCR.
For
all
other
technical
inquiries
contact:
Judy
Lebowich,
(
202)
564
 
4884,
e­
mail:
lebowich.
judy@
epa.
gov,
or
Wynne
Miller,
(
202)
564
 
4887,
e­
mail:
miller.
wynne@
epa.
gov.
General
information
may
also
be
obtained
from
the
EPA
Safe
Drinking
Water
Hotline.
Callers
within
the
United
States
may
reach
the
Hotline
at
(
800)
426
 
4791.
The
Hotline
is
open
Monday
through
Friday,
excluding
Federal
holidays,
from
9
a.
m.
to
5:
30
p.
m.
Eastern
Time.
SUPPLEMENTARY
INFORMATION:

Table
of
Contents
I.
General
Information
A.
Does
this
Notice
Apply
to
My
Public
Water
System?
B.
How
Can
I
Get
Copies
of
Related
Information?
1.
Docket
2.
Electronic
Access
II.
Background
A.
What
Is
the
Statutory
Requirement
for
the
Six­
Year
Review?
B.
What
Has
the
Agency
Done
to
Address
the
Statutory
Requirement?
III.
EPA's
Current
Revise/
Not
Revise
Decisions
for
the
69
Pre­
1997
NPDWRs
IV.
Summary
of
Major
Comments
and
New
Information
and
the
Agency's
Response
A.
What
Did
Commenters
Say
Regarding
the
Reasonableness
and
Appropriateness
of
EPA's
Six­
Year
Review
Approach?
1.
Overall
Approach
and
Decision
Criteria
2.
Health
Effects
Technical
Review
3.
Analytical
Methods
Feasibility
Technical
Review
4.
Review
of
Treatment
Technologies
and
Related
Issues
5.
Review
of
Implementation­
Related
Issues
6.
Review
of
Occurrence
and
Exposure
7.
Consideration
of
Available
Economic
Information
B.
What
Comments
or
New
Information
Did
EPA
Receive
on
Chemical
Contaminant­
Specific
Issues?
1.
Alachlor
2.
Antimony
3.
Atrazine
4.
Beryllium
5.
Carbofuran
6.
Chromium
7.
1,1­
Dichloroethylene
8.
Dichloromethane
9.
Di(
2­
ethylhexyl)
adipate
(
DEHA)
10.
Di(
2­
ethylhexyl)
phthalate
(
DEHP)
11.
Fluoride
12.
Glyphosate
13.
Lead
and
Copper
14.
Lindane
(
g­
hexachlorocyclohexane)
15.
Simazine
C.
What
Comments
Did
EPA
Receive
Regarding
the
Review
of
Implementation­
Related
Issues
for
Chemical
NPDWRs?
D.
What
Comments
Did
EPA
Receive
on
the
Total
Coliform
Rule?
E.
What
Comments
Did
EPA
Receive
on
Research
Needs?
V.
References
List
of
Tables
Table
III
 
1:
Current
Revise/
Not
Revise
Decisions
for
the
68
Chemical
NPDWRs
and
the
TCR
Table
IV
 
1:
1,1­
Dichloroethylene
Occurrence
Table
IV
 
2:
Lindane
Occurrence
I.
General
Information
A.
Does
This
Notice
Apply
to
My
Public
Water
System?

This
action
itself
does
not
impose
any
requirements
on
anyone.
Instead,
it
notifies
interested
parties
of
the
availability
of
EPA's
responses
to
comments
received
on
EPA's
Six­
Year
Review
protocol
and
the
Agency's
current
revise/
not
revise
decisions
for
69
NPDWRs.
B.
How
Can
I
Get
Copies
of
Related
Information?

1.
Docket
EPA
has
established
an
official
public
docket
for
this
action
under
Docket
ID
No.
OW
 
2002
 
0012.
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/
DC)
EPA
West,
Room
B102,
1301
Constitution
Ave.,
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
at
http://
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
view
public
comments,
access
the
index
listing
of
the
contents
of
the
official
public
docket,
and
access
those
documents
in
the
public
docket
that
are
available
electronically.
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
section
I.
B.
1.
Once
in
the
system,
select
``
search,''
then
key
in
the
appropriate
docket
identification
number.

Abbreviations
and
Acronyms
Used
in
This
Action
BAT
 
best
available
technology
CBI
 
confidential
business
information
CCL
 
contaminant
candidate
list
CFR
 
Code
of
Federal
Regulations
CMR
 
Chemical
Monitoring
Reform
DACT
 
diaminochlorotriazine
DEA
 
desethyl
atrazine
DEHA
 
di(
2­
ethylhexyl)
adipate
DEHP
 
di(
2­
ethylhexyl)
phthalate
DIA
 
desisopropyl
atrazine
EPA
 
United
States
Environmental
Protection
Agency
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/
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18,
2003
/
Notices
1
These
include:
(
1)
EPA's
overall
protocol
for
the
review
of
NPDWRs
(
USEPA,
2003c);
(
2)
health
effects
(
USEPA,
2003f);
(
3)
analytical
methods
feasibility
(
USEPA,
2003a);
(
4)
treatment
technology
(
USEPA,
2003g);
(
5)
consideration
of
other
regulatory
revisions
(
USEPA,
2003b);
(
6)
occurrence
and
exposure
(
USEPA,
2003d;
USEPA,
2002f);
(
7)
and
economic
considerations
(
USEPA,
2002c).
EPA/
DC
 
EPA
Docket
Center
FQPA
 
Food
Quality
Protection
Act
FR
 
Federal
Register
IOC
 
inorganic
chemical
IRED
 
interim
reregistration
eligibility
decision
IRIS
 
Integrated
Risk
Information
System
LCCA
 
Lead
Contamination
Control
Act
of
1988
LCR
 
Lead
and
Copper
Rule
MCL
 
maximum
contaminant
level
MCLG
 
maximum
contaminant
level
goal
MDL
 
method
detection
limit
mg/
kg/
day
 
milligram(
s)
per
kilogram
of
body
weight
per
day
mg/
L
 
milligram(
s)
per
liter
MYP
 
multi­
year
plan
NAS
 
National
Academy
of
Sciences
NCOD
 
National
Contaminant
Occurrence
Database
NDWAC
 
National
Drinking
Water
Advisory
Council
NPDWR
 
National
Primary
Drinking
Water
Regulation
NRC
 
National
Research
Council
NTP
 
National
Toxicology
Program
NTNCWS
 
non­
transient
noncommunity
water
system
Occurrence
Methodology
Document
 
Occurrence
Estimation
Methodology
and
Occurrence
Findings
Report
for
the
Six­
Year
Review
of
Existing
National
Primary
Drinking
Water
Regulations
Occurrence
Summary
Document
 
Occurrence
Summary
and
Use
Support
Document
for
the
Six­
Year
Review
of
Existing
National
Primary
Drinking
Water
Regulations
OPP
 
Office
of
Pesticide
Programs
OW
 
Office
of
Water
PE
 
performance
evaluation
PHS
 
Public
Health
Service
PQL
 
practical
quantitation
level
Protocol
Document
 
EPA
Protocol
for
Review
of
Existing
National
Primary
Drinking
Water
Regulations
RED
 
reregistration
eligibility
decision
RfD
 
reference
dose
ROS
 
regression
on
ordered
statistics
RSC
 
relative
source
contribution
SAB
 
Science
Advisory
Board
SAP
 
Science
Advisory
Panel
SDWA
 
Safe
Drinking
Water
Act
SOC
 
synthetic
organic
chemical
TCR
 
Total
Coliform
Rule
TMDLs
 
total
maximum
daily
loads
Treatment
Feasibility
Document
 
Water
Treatment
Technology
Feasibility
Support
Document
for
Chemical
Contaminants;
In
Support
of
EPA
Six­
Year
Review
of
National
Primary
Drinking
Water
Regulations
TT
 
treatment
technique
VOC
 
volatile
organic
chemical
WQP
 
water
quality
parameter
WS
 
water
supply
II.
Background
A.
What
Is
the
Statutory
Requirement
for
the
Six­
Year
Review?

Under
the
Safe
Drinking
Water
Act
(
SDWA),
as
amended
in
1996,
EPA
must
periodically
review
existing
National
Primary
Drinking
Water
Regulations
(
NPDWRs)
and,
if
appropriate,
revise
them.
Section
1412(
b)(
9)
of
SDWA
states:

The
Administrator
shall,
not
less
often
than
every
6
years,
review
and
revise,
as
appropriate,
each
national
primary
drinking
water
regulation
promulgated
under
this
title.
Any
revision
of
a
national
primary
drinking
water
regulation
shall
be
promulgated
in
accordance
with
this
section,
except
that
each
revision
shall
maintain,
or
provide
for
greater,
protection
of
the
health
of
persons.

B.
What
Has
the
Agency
Done
To
Address
the
Statutory
Requirement?

The
Agency
developed
a
systematic
process,
or
protocol,
for
the
review
of
existing
NPDWRs
in
accordance
with
the
SDWA
requirements
and
applied
the
protocol
to
the
review
of
the
NPDWRs
for
total
coliforms
and
68
inorganic
and
organic
chemicals
published
prior
to
the
SDWA
1996
Amendments
(
i.
e.,
pre­
1997
NPDWRs).
In
the
April
17,
2002,
Federal
Register,
EPA
provided:
 
A
description
of
the
review
protocol;
 
A
detailed
discussion
of
how
the
protocol
was
applied
in
assessing
each
of
the
69
pre­
1997
NPDWRs;
 
The
preliminary
results
of
each
of
the
technical
reviews,
and
the
preliminary
decision
for
each
NPDWR;
and
 
A
request
for
the
public
to
comment
on
any
aspect
of
the
Agency's
protocol
and
preliminary
decisions.
Please
refer
to
the
April
17,
2002,
Federal
Register
for
the
detailed
discussion
of
EPA's
revise/
not
revise
decisions
for
each
of
the
69
NPDWRs.
Today's
action
briefly
summarizes
the
major
public
comments,
other
new
information,
and
EPA's
current
revise/
not
revise
decisions
for
the
69
NPDWRs.
Today's
action
only
discusses
in
detail
those
decisions
or
rationales
that
were
affected
by
public
comments
or
other
new
information
that
has
become
available
since
April
2002.
In
June
2002,
EPA
consulted
with
the
Science
Advisory
Board
(
SAB)
Drinking
Water
Committee
and
requested
their
review
and
comment
on
whether
the
protocol
EPA
developed
based
on
the
National
Drinking
Water
Advisory
Council
(
NDWAC)
recommendations
was
consistently
applied
and
appropriately
documented.
The
SAB
provided
verbal
feedback
regarding
the
transparency
and
clarity
of
EPA's
decision
criteria
for
making
its
revise/
not
revise
decisions
under
the
current
review.
EPA
has
revised
this
protocol
document
to
better
explain
how
the
decision
criteria
were
applied
and
will
also
take
the
SAB
comments
into
consideration
when
planning
for
the
next
review
cycle.

III.
EPA's
Current
Revise/
Not
Revise
Decisions
for
the
69
Pre­
1997
NPDWRs
EPA
received
comments
from
44
commenters
on
its
preliminary
revise/
not
revise
decisions
in
the
April
17,
2002,
Federal
Register.
The
Agency
responded
to
these
comments
in
the
``
Public
Comment
and
Response
Summary
for
the
Six­
Year
Review
of
National
Primary
Drinking
Water
Regulations''
(
USEPA,
2003e),
which
is
available
in
the
Water
Docket
in
the
EPA
Docket
Center
and
at
the
EPA
Dockets
Web
site
http://
www.
epa.
gov/
epadocket/.
Other
technical
support
documents
1
for
the
decisions
discussed
in
today's
action
are
also
available
in
the
Water
Docket
and
at
the
EPA
Dockets
Web
site
http://
www.
epa.
gov/
epadocket/
and
the
Safewater
Web
site
http://
www.
epa.
gov/
safewater/.
Based
on
the
Agency's
preliminary
review,
as
well
as
the
public
comments
received
and
other
new
information,
EPA
believes
that
it
is
appropriate
to
revise
the
Total
Coliform
Rule
(
TCR).
The
Agency
also
believes
that
it
is
not
appropriate
to
revise
the
68
chemical
NPDWRs
at
this
time.
However,
for
the
reasons
discussed
in
sections
IV.
B.
7,
IV.
B.
13,
and
IV.
B.
14
of
today's
action,
the
Agency
has
modified
the
basis
of
its
not
revise
findings
for
1,1­
dichloroethylene,
lead,
and
lindane,
respectively.
Table
III
 
1
reflects
the
Agency's
current
revise/
not
revise
decisions
for
the
69
NPDWRs.
As
indicated
in
Table
III
 
1,
EPA's
decision
not
to
revise
an
NPDWR
at
this
time
is
based
on
one
of
the
following
reasons:
 
Health
risk
assessment
is
in
process:
As
of
December
31,
2002,
the
Agency
is
currently
conducting,
or
has
scheduled,
a
detailed
review
of
current
health
effects
information.
Because
the
results
of
the
assessment
are
not
yet
available,
or
were
not
available
in
time
for
consideration
under
the
1996
 
2002
review
cycle,
the
Agency
does
not
believe
it
is
appropriate
to
revise
the
NPDWR
at
this
time.
In
these
cases,
EPA
will
consider
the
results
of
the
updated
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Friday,
July
18,
2003
/
Notices
health
risk
assessment
during
the
2002
 
2008
review
cycle.
If
the
results
of
the
health
risk
assessment
indicate
a
compelling
reason
to
reconsider
the
maximum
contaminant
level
goal
(
MCLG),
EPA
may
decide
to
accelerate
the
review
schedule
for
that
contaminant's
NPDWR.
 
NPDWR
remains
appropriate
after
data/
information
review:
The
outcome
of
the
review
indicates
that
the
current
regulatory
requirements
remain
appropriate,
and
therefore,
no
regulatory
revisions
are
warranted.
Any
new
information
available
to
the
Agency
either
supports
the
current
regulatory
requirements
or
does
not
justify
a
revision.

 
New
information,
but
no
revision
appropriate
at
this
time
because:

 
Low
priority:
In
EPA's
judgment,
any
resulting
revisions
to
the
NPDWR
would
not
provide
a
meaningful
opportunity
for
health
risk
reduction
or
result
in
meaningful
cost­
savings
to
public
water
systems
and
their
customers.
These
revisions
are
a
low
priority
activity
for
the
Agency
and,
thus,
are
not
appropriate
for
revision
at
this
time
because
of
one
or
more
of
the
following
considerations:
competing
workload
priorities;
the
administrative
costs
associated
with
rulemaking;
and
the
burden
on
States
and
the
regulated
community
to
implement
any
regulatory
change
that
resulted.

 
Information
gaps:
Although
results
of
the
review
support
consideration
of
a
possible
revision,
the
available
data
are
insufficient
to
support
a
definitive
regulatory
decision
at
this
time.

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IV.
Summary
of
Major
Comments
and
New
Information
and
the
Agency's
Response
This
section
summarizes
the
major
public
comments,
including
the
Agency's
response,
and
other
new
information,
and
explains
any
modifications
to
EPA's
preliminary
revise/
not
revise
decisions.
For
a
more
detailed
summary
of
the
comments
and
the
Agency's
response,
please
refer
to
the
document:
``
Public
Comment
and
Response
Summary
for
the
Six­
Year
Review
of
National
Primary
Drinking
Water
Regulation''
(
USEPA,
2003e).

A.
What
Did
Commenters
Say
Regarding
the
Reasonableness
and
Appropriateness
of
EPA's
Six­
Year
Review
Approach?

1.
Overall
Approach
and
Decision
Criteria
a.
Adequacy
of
the
Review.
Commenters
generally
agreed
that
EPA
had
identified
the
appropriate
key
elements
of
the
review.
However,
some
commenters
stated
that
the
Agency
could
have
done
more
in
some
areas
(
e.
g.,
implementation)
and
a
few
commenters
expressed
the
opinion
that
the
Agency's
review
process
contains
weaknesses,
or
was
not
applied
appropriately,
because
it
did
not
identify
any
chemical
NPDWRs
for
revision
at
this
time.
EPA
Response:
The
Agency
believes
that
its
basic
review
protocol
and
decision
rationale
are
reasonable
and
appropriate.
Even
though
EPA's
application
of
the
protocol
did
not
identify
any
chemical
NPDWRs
for
revision
at
this
time,
that
is
not
a
reason
to
reject
or
modify
the
protocol.
The
review
did
result
in
the
initiation
of
health
risk
assessments
for
three
contaminants
and
efforts
to
address
data
gaps/
research
needs
for
several
other
contaminants.
Health
risk
assessments
are
underway
for
approximately
half
of
the
chemical
contaminants
addressed
in
today's
action.
The
Agency
expects
most
of
these
assessments
to
be
completed
within
the
next
few
years.
When
completed,
these
assessments
will
support
further
analysis
that
may
result
in
different
revise/
not
revise
decisions
as
part
of
the
ongoing
Six­
Year
Review
process.
b.
Criteria
for
Deciding
that
an
MCLG/
MCL
Revision
is
Appropriate
and
Definition
of
``
Significant''
and
``
Negligible.''
While
some
commenters
agreed,
others
disagreed
with
the
Agency's
consideration
of
estimated
changes
in
occurrence
levels
and
available
economic
information
whenever
a
health
or
technological
basis
exists
to
revise
a
standard.
For
example,
some
commenters
felt
that
EPA
should
revise
the
MCLG
and,
as
appropriate,
the
maximum
contaminant
level
(
MCL),
whenever
a
health
basis
exists,
regardless
of
other
considerations.
A
few
commenters
criticized
the
Agency
for
not
defining
what
it
considers
``
significant''
and
``
negligible''
gains
in
public
health
protection
and/
or
costsavings
in
terms
of
regulatory
revision.
EPA
Response:
Section
1412(
b)(
9)
of
SDWA,
as
amended
in
1996,
provides
the
Administrator
with
broad
discretion
to
determine
when
a
revision
to
an
NPDWR
is
appropriate.
As
a
part
of
this
determination,
the
Agency
believes
it
is
reasonable
to
consider
whether
a
potential
revision
is
likely
to
provide
a
meaningful
opportunity
for
health
risk
reduction.
This
criterion
is
consistent
with
the
statutory
provisions
governing
the
regulatory
determination
process
under
section
1412(
b)(
1)(
A)
for
contaminants
not
currently
regulated.
EPA
also
believes
it
is
reasonable
to
consider
the
extent
of
potential
costsavings
for
public
water
systems
and
their
customers
when
determining
whether
revisions
that
potentially
would
result
in
a
relaxed
standard
(
i.
e.,
where
a
health
basis
exists
for
a
less
stringent
standard)
or
streamlined
implementation
are
appropriate.
These
considerations
allow
the
Administrator
to
better
prioritize
efforts
that
are
most
likely
to
result
in
a
meaningful
opportunity
for
health
risk
reduction
or
cost­
savings
to
public
water
systems
and
their
customers.
Revisions
that
do
not
satisfy
at
least
one
of
these
criteria
are
a
low
priority
activity
for
the
Agency,
and
thus
are
not
appropriate
at
this
time
because
of
one
or
more
of
the
following
considerations:
 
Competing
workload
priorities;
 
The
administrative
costs
associated
with
rulemaking;
and
 
The
burden
on
States
and
the
regulated
community
to
implement
any
regulatory
change
that
resulted.
EPA
believes
that
the
determination
of
whether
the
impact
of
a
potential
revision
is
``
significant''
or
``
negligible''
is
a
matter
of
judgment
that
depends
on
a
number
of
variables,
not
all
of
which
are
amenable
to
precise
definition.
However,
EPA
recognizes
that
the
use
of
``
negligible/
significant''
terminology
may
imply
more
precision
and
quantitation
in
the
determination
than
is
possible.
The
Agency
also
understands
that
the
use
of
the
term
``
negligible''
may
imply
to
some
that
the
Agency
is
belittling
small
gains
in
health
risk
reduction.
This
is
not
the
Agency's
intent.
Accordingly,
in
today's
action,
the
Agency
has
explained
its
rationale
more
clearly
in
terms
of
the
criteria
noted
in
the
previous
paragraph.
c.
Authority
to
Relax
an
Existing
Standard
and
Deregulation
of
Low/
Non­
Occurring
Contaminants.
Some
commenters
argued
that
the
Agency
should
never
consider
relaxing
a
standard
because
doing
so,
by
definition,
would
lessen
the
level
of
public
health
protection.
Other
commenters
encouraged
the
Agency
to
actively
consider
deregulating
contaminants
that
have
low
occurrence
or
do
not
appear
to
be
occurring
in
finished
water
or,
at
a
minimum,
to
further
reduce
the
frequency
of
monitoring
for
these
contaminants.
EPA
Response:
EPA
disagrees
with
those
commenters
who
oppose
relaxing
a
standard
for
any
reason.
The
legislative
history
of
the
SDWA
Amendments
of
1996
makes
clear
that
Congress
envisioned
the
possibility
that
a
relaxed
standard
might
be
appropriate
under
circumstances
that
would
not
result
in
a
lessening
of
the
level
of
public
health
protection.
In
its
discussion
of
potential
revisions
to
an
existing
drinking
water
standard,
Senate
Report
Number
104
 
169
(
available
electronically
at
http://
thomas.
loc.
gov/)
states:

Amendments
made
by
the
bill
require
that
any
future
standard
issued
for
a
contaminant
already
regulated
must
maintain
or
provide
for
greater
protection
of
the
health
of
persons.
Generally,
this
will
preclude
the
promulgation
of
a
revised
standard
for
a
contaminant
that
is
less
stringent
than
the
standard
already
in
place.
However,
there
are
circumstances
under
which
a
standard
may
be
relaxed.
The
maximum
contaminant
level
goal
for
a
contaminant
is
set
at
a
level
at
which
there
is
no
adverse
effect
on
the
health
of
persons
with
an
adequate
margin
of
safety.
New
scientific
information
may
cause
the
MCLG
to
be
revised
and
in
some
cases
these
revisions
may
be
to
less
stringent
levels.
This
may
lead
to
a
revision
of
the
maximum
contaminant
level
since
it
need
be
no
more
stringent
than
the
MCLG.
New
information
may
also
allow
for
a
smaller
margin
of
safety
because
it
narrows
the
range
of
uncertainty
for
estimates
of
health
risks.
Finally,
some
substances
which
have
been
regulated
as
carcinogens
for
ingestion
in
drinking
water
may
be
reclassified
(
as
asbestos
has
been
in
the
most
recent
revision)
or
assigned
a
threshold
for
the
effect
based
on
new
scientific
information.
In
each
of
these
cases,
EPA
may
issue
a
revised
standard
for
a
contaminant
that
is
less
stringent
than
the
one
it
replaces.
(
S.
Rep.
104
 
169,
104th
Cong.,
1st
Sess.
(
1995)
at
38)

However,
because
section
1412(
b)(
9)
of
SDWA
requires
that
any
revision
to
an
existing
NPDWR
maintain
or
improve
the
level
of
public
health
protection,
EPA
believes
that
a
clear,
technically­
based
demonstration
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regarding
the
absence
of
potential
risk
is
necessary
to
deregulate
a
contaminant.
EPA
does
not
believe
it
is
appropriate
to
deregulate
any
currently
regulated
contaminant
at
this
time
because
the
Agency
is
not
able
to
make
a
determination,
pursuant
to
section
1412(
b)(
9)
of
SDWA,
that
there
would
be
no
lessening
of
public
health
protection
if
the
contaminant
were
deregulated.
The
Agency
disagrees
that
evaluation
of
finished
water
data
is
sufficient
to
consider
deregulation
of
low
or
non­
occurring
contaminants.
The
apparent
low
or
non­
occurrence
of
these
contaminants
in
finished
water
may
be
the
result
of
effective
treatment
processes
in
place
rather
than
the
lack
of
occurrence
in
source
water.
EPA
believes
that
the
existing
waiver
provisions
in
the
SDWA
regulations
give
States
sufficient
flexibility
to
reduce
or
potentially
eliminate
monitoring
of
a
chemical
contaminant,
where
appropriate.
States
that
have
primacy
for
the
drinking
water
regulations
are
responsible
for
their
waiver
programs
and
can
grant
waivers
if
a
particular
pesticide
or
herbicide
has
not
been
previously
used,
manufactured,
stored,
transported,
or
disposed
in
the
area,
a
system's
source
water
is
not
susceptible
to
contamination
from
the
chemical,
or
the
State
has
determined
the
system
is
not
vulnerable.
The
State
can
grant
waivers
for
individual
contaminants,
a
group
of
contaminants,
or
issue
an
area­
wide
waiver
(
see
40
CFR
141.23
(
b)
and
(
c),
and
141.24
(
f)
and
(
h)).
In
addition,
States
can
adopt
alternative
monitoring
strategies
as
long
as
the
approach
is
as
stringent
as
the
Federal
requirements
(
USEPA,
1997b).

2.
Health
Effects
Technical
Review
a.
Contaminants
Undergoing
Health
Risk
Assessments.
A
few
commenters
raised
issues
with
respect
to
the
36
chemical
contaminants
for
which
health
risk
assessments
were
underway
when
EPA
published
its
preliminary
revise/
not
revise
decisions
in
the
April
17,
2002,
Federal
Register.
In
particular,
these
commenters
wanted
to
know
the
process
that
EPA
plans
to
follow
to
review
each
NPDWR
once
the
risk
assessment
is
completed,
including
when
that
review
would
occur
and
when
an
accelerated
review
would
be
appropriate.
EPA
Response:
Between
April
and
August
2002,
the
Agency
completed
health
risk
assessments
for
2
of
the
36
contaminants:
1,1­
dichloroethylene
and
lindane.
The
results
of
those
assessments
and
the
impact
on
the
Agency's
revise/
not
revise
decisions
are
discussed
in
sections
IV.
B.
7
and
IV.
B.
14,
respectively,
of
today's
action.
NPDWRs
for
the
remaining
contaminants
for
which
health
risk
assessments
are
in
process
will
be
reviewed
as
a
part
of
the
2002
 
2008
review
cycle.
However,
if
in
the
Agency's
judgment,
a
compelling
reason
exists
to
revisit
the
``
not
revise''
decision
sooner,
EPA
may
accelerate
the
review
cycle
for
that
NPDWR.
In
reviewing
these
regulations,
EPA
expects
to
apply
an
approach
consistent
with
the
protocol
used
for
the
current
review.
That
is,
the
Agency
will
consider
the
same
key
elements
and
apply
the
same
basic
decision
tree
for
making
a
revise/
not
revise
decision.
The
key
elements
of
the
review
include
health
effects
technical
review,
technology
review,
other
regulatory
revisions
review,
and,
if
appropriate,
occurrence/
exposure
analyses
and
consideration
of
available
economic
information
(
see
67
FR
19030
at
19038,
April
17,
2002
(
USEPA,
2002g)).
b.
Other
Issues
Related
to
the
Health
Effects
Technical
Review.
One
commenter
stated
that
the
Agency
risk
assessments
underestimate
risk
because
absorption
of
chemicals
through
the
skin,
lung,
and
nose
is
not
``
adequately''
taken
into
account.
Another
commenter
encouraged
the
Agency
to
evaluate
the
literature
for
potential
reproductive
and
developmental
effects
for
chemicals
with
zero
MCLGs
since
risk
management
strategies,
such
as
monitoring
frequency
or
treatment
requirements,
may
be
affected
by
such
information.
EPA
Response:
EPA
disagrees
that
the
Agency
underestimates
risk
when
deriving
MCLGs.
The
Agency
takes
multiple
routes
of
exposure
into
account
by
including
a
relative
source
contribution
(
RSC)
in
its
calculation
of
an
MCLG
value.
The
RSC
compares
exposure
from
air,
food,
and
drinking
water
and
uses
the
data
in
allocating
a
portion
of
the
total
exposure
to
drinking
water.
When
exposure
data
for
the
chemical
are
not
available,
EPA
assumes
that
the
RSC
from
drinking
water
is
20
percent
of
the
total
exposure.
This
allows
80
percent
of
the
total
exposure
to
come
from
sources
other
than
drinking
water,
such
as
exposure
from
food,
inhalation,
or
dermal
contact.
EPA
recognizes
the
possibility
that
some
chemicals
with
zero
MCLGs
may
also
be
of
reproductive
and/
or
developmental
concern.
EPA
is
investigating
these
endpoints
and
their
potential
impact
on
monitoring
frequency
or
treatment
requirements.
However,
the
Agency
does
not
believe
the
analysis
can
be
completed
during
the
current
review
cycle
without
significantly
delaying
the
current
revise/
not
revise
decisions.
To
the
extent
possible,
EPA
will
consider
the
results
of
this
analysis
and
any
additional
information
during
subsequent
Six­
Year
Reviews.

3.
Analytical
Methods
Feasibility
Technical
Review
Commenters
generally
supported
the
Agency's
approach
of
using
Performance
Evaluation
(
PE)
Water
Supply
(
WS)
data
and
the
10
times
method
detection
limit
(
MDL)
multiplier
to
evaluate
possible
changes
in
analytical
feasibility
for
several
of
the
contaminants
under
this
Six­
Year
Review.
A
few
commenters
agreed
that
the
WS
data
are
a
valuable
source
of
information
for
evaluating
interlaboratory
performance
and
for
developing
practical
quantitation
levels
(
PQLs).
However,
the
same
commenters
questioned
whether
the
approach
of
using
PE
WS
data
will
be
possible
for
future
reviews
since
the
Agency's
laboratory
certification
program
that
once
collected
this
information
has
been
externalized
to
private
providers.
These
commenters
questioned
whether
the
externalized
or
privatized
data
would
be
sufficient
for
the
determination
and/
or
re­
evaluation
of
PQLs.
In
addition,
at
least
one
commenter
suggested
that
it
may
be
appropriate
(
in
the
next
Six­
Year
Review)
to
re­
evaluate
the
policy
of
basing
the
PQL
on
only
EPA
Regional
and
State
laboratory
results,
and
recommended
that
the
Agency
include
commercial
and
large
utility
laboratory
results.
According
to
the
commenter,
these
laboratories
(
commercial
and
large
utility)
have
demonstrated
``
significant
innovation
in
method
development
and
improved
quantitation.''
EPA
Response:
EPA
agrees
that
the
WS
studies
have
been
a
valuable
source
of
information
for
determining
PQLs.
At
this
time,
the
Agency
has
not
determined
whether
the
privatized
data
will
be
sufficient
for
the
purposes
mentioned
by
the
commenter.
In
addition,
the
Agency
has
not
yet
determined
how
best
to
gather
data
to
determine
and/
or
reassess
PQLs
for
future
reviews.
The
Agency
is
in
the
process
of
evaluating
acceptable
options.
The
policy
for
determining
the
most
appropriate
methodology
for
calculating
PQLs
for
drinking
water
contaminants
is
outside
the
scope
of
the
Six­
Year
Review.

4.
Review
of
Treatment
Technologies
and
Related
Issues
Commenters
suggested
that,
while
EPA's
review
of
existing
NPDWRs
was
generally
consistent
with
the
NDWAC
recommendations
to
EPA
(
NDWAC,
2000),
the
Agency's
review
of
treatment
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technologies
which
support
the
regulations
should
be
expanded.
Specifically,
commenters
recommended
that
EPA
review
all
treatment
technique
(
TT)
requirements
and
allow
for
changing
or
expanding
these
TT
requirements
where
new
information
warrants
such
a
change.
EPA
Response:
EPA
continues
to
believe
its
approach
to
reviewing
TT
requirements
is
appropriate.
The
``
EPA
Protocol
for
the
Review
of
Existing
NPDWRs''
(
Protocol
Document)
discusses
when
it
is
appropriate
for
the
Agency
to
consider
revisions
to
TT­
type
regulations
(
see
sections
II.
C
and
III.
B
of
the
Protocol
documents)
(
USEPA,
2002d;
USEPA,
2003c).
The
Agency
discussed
the
review
of
the
four
chemical
treatment
technique
NPDWRs
(
i.
e.,
acrylamide,
copper,
epichlorohydrin,
and
lead)
in
both
the
draft
and
final
``
Water
Treatment
Technology
Feasibility
Support
Document
for
Chemical
Contaminants;
In
Support
of
EPA
Six­
Year
Review
of
National
Primary
Drinking
Water
Regulations''
(
Treatment
Feasibility
Documents)
(
USEPA,
2002b;
USEPA,
2003g).
The
Agency
has
no
specific
information
that
provides
a
basis
for
revisions
to
TT
requirements
at
this
time.
However,
EPA
believes
that
research
data
in
a
number
of
treatmentrelated
areas
may
be
useful
in
future
reviews
of
NPDWRs.
The
Agency
is
committed
to
working
with
stakeholders
to
identify
and
prioritize
treatmentrelated
research
needs,
and
to
work
with
EPA's
research
partners
to
address
the
highest
priority
needs.

5.
Review
of
Implementation­
Related
Issues
While
several
commenters
felt
overall
that
EPA's
Six­
Year
Review
protocol
was
reasonable
and
appropriate,
they
encouraged
EPA
to
consider
implementation­
related
modifications
(
i.
e.,
``
other
regulatory
revisions'')
as
a
reason
to
revise
a
rule,
even
if
there
were
no
basis
to
revise
the
MCLG
and/
or
MCL/
TT
requirements.
EPA
Response:
Implementationrelated
issues
are
the
primary
reason
for
the
Agency's
decision
to
revise
the
TCR
at
this
time
(
67
FR
19030
at
19085,
April
17,
2002
(
USEPA,
2002g)),
so
it
is
clear
that
EPA
considered
implementedrelated
issues
in
its
review.
The
Protocol
Document
(
USEPA,
2002d;
USEPA,
2003c)
identifies
the
conditions
under
which
the
Agency
will
consider
implementation­
related
revisions.
EPA
continues
to
believe
these
criteria
are
appropriate.
During
the
current
review,
none
of
the
identified
potential
implementation­
related
revisions
pertaining
to
the
chemical
NPDWRs,
in
EPA's
judgment,
met
the
stated
criteria
for
reasons
documented
in
EPA's
final
document,
``
Consideration
of
Other
Regulatory
Revisions
for
Chemical
Contaminants
in
Support
of
the
Six­
Year
Review
of
National
Primary
Drinking
Water
Regulations''
(
USEPA,
2003b).

6.
Review
of
Occurrence
and
Exposure
a.
Occurrence
Database
Concerns.
A
few
commenters
asked
for
information
regarding
next
steps
for
the
National
Contaminant
Occurrence
Database
(
NCOD).
Another
commenter
pointed
out
that
States
have
been
willing
to
assist
EPA
by
providing
occurrence
data
beyond
what
is
required
of
them.
However,
the
commenter
raised
concerns
that
he/
she
felt
EPA
needs
to
address
to
facilitate
further
data
sharing.
Some
commenters
expressed
concern
about
the
completeness
and
representativeness
of
the
16­
State
data
set
used
for
the
Six­
Year
Review.
One
commenter
suggested
that
the
Agency
should
have
issued
an
Information
Collection
Request
to
obtain
more
complete
data
for
the
Six­
Year
Review
analysis.
EPA
Response:
The
Agency
is
updating
the
NCOD
to
provide
sample
data
that
have
been
quality
checked
and
used
in
various
EPA
analyses.
This
update
to
NCOD
includes
unregulated
occurrence
data
collected
prior
to
1999
as
well
as
the
latest
Unregulated
Contaminant
Monitoring
Rule
data
(
64
FR
50556,
September
17,
1999
(
USEPA,
1999b))
reported
by
laboratories
for
public
water
systems
required
to
report
results.
It
also
includes
the
data
used
for
the
Six­
Year
Review
of
regulated
contaminants.
EPA
appreciates
that
some
States
are
willing
to
share
their
full
compliance
monitoring
records
with
the
Agency,
even
though
it
is
not
required.
The
Agency
and
the
States
are
continuing
to
work
together
to
establish
a
protocol
for
data
sharing,
including
safeguards
to
prevent
misuse
and
misinterpretation
of
data.
The
16­
State
cross­
section
data
set
compiled
for
occurrence
analyses
for
the
Six­
Year
Review
is
the
largest
compliance
monitoring
data
set
for
drinking
water
assembled
by
EPA
to
date.
The
design
and
construction
of
the
16­
State
cross­
section
data
set
was
based
on
the
fact
that
contaminant
occurrence
varies
spatially
(
geographically)
due
to
differing
patterns
of
population,
land
use,
chemical
use,
geology,
hydrology,
and
climate.
The
detailed
description
of
the
``
pollution­
potential''
and
geographic
diversity
considerations,
and
the
derived
balanced
cross­
section
of
States
(
that
was
developed
to
be
collectively
indicative
of
national
occurrence)
is
included
in
the
``
Occurrence
Estimation
Methodology
and
Occurrence
Findings
Report
for
the
Six­
Year
Review
of
Existing
National
Primary
Drinking
Water
Regulations''
(
Occurrence
Methodology
Document)
(
USEPA,
2003d).
EPA
selected
its
16­
State
cross­
section
to
be
as
representative
as
possible
of
national
contaminant
occurrence.
In
EPA's
judgment,
these
States
provide
a
reasonable
cross­
section
of
agricultural
and
industrial
pollution
potential,
as
described
in
the
Occurrence
Methodology
Document,
and
also
provide
geographic
coverage
of
the
United
States.
Therefore,
EPA
believes
that
the
data
assembled
from
these
States
is
the
most
representative
data
currently
available
of
national
contaminant
occurrence.
The
Agency
did
receive
occurrence
data
from
States
other
than
those
in
its
16­
State
cross­
section.
However,
many
State
data
sets
contained
incomplete
records
(
e.
g.,
no
water
type
or
population
records
specified)
or
had
other
quality
problems.
Therefore,
they
were
not
included
in
the
analyzed
data
set.
b.
Occurrence
Analysis
Methodology.
One
commenter
noted
that
while
the
occurrence
estimation
methodology
has
several
strengths,
it
also
has
a
number
of
flaws.
The
commenter
was
concerned
about
the
large
proportion
of
nondetected
observations
in
the
occurrence
data,
and
the
difficulty
of
verifying
the
assumptions
made
by
the
Agency.
The
commenter
agreed
that
EPA's
occurrence
analysis
may
represent
a
``
decent''
estimate
given
the
limitations
of
the
data.
The
commenter
also
noted
that
the
occurrence
estimation
methodology
is
premised
on
``
subjective
decisions
or
qualitative
observations
*
*
*
rather
than
documented,
statistically­
based
quantitative
ones''
and
would
like
to
have
seen
alternate
approaches
used
to
provide
confirmation
of
the
estimates.
In
addition,
the
commenter
questioned
why
the
Agency
used
``
modeled
data
sets
to
test
the
model
rather
than
a
standard
statistical
strategy
of
basing
the
model
on
a
portion
of
the
data
set
and
using
the
remainder
to
test
the
model.''
One
commenter
stated
that
the
Stage
2
analysis
(
Bayesian
analysis)
was
poorly
described
and
that
this
conflicts
with
the
transparency
requirements
of
the
1996
SDWA
Amendments.
In
addition,
the
commenter
asked
EPA
to
clarify
how
the
occurrence
data
from
other
survey
efforts,
which
are
summarized
in
``
Occurrence
Summary
and
Use
Support
Document
for
the
Six­
Year
Review
of
Existing
National
Primary
Drinking
Water
Regulations''

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18,
2003
/
Notices
(
Occurrence
Summary
Document)
(
USEPA,
2002f),
were
used
to
inform
the
modeling
effort.
EPA
Response:
EPA's
occurrence
model
development
work
was
significantly
revised
to
reflect
peer
review
comments
prior
to
the
March
2002
Occurrence
Methodology
Document
(
USEPA,
2002e)
and
the
April
17,
2002,
Federal
Register.
The
additional
work
involved
the
development
of
a
detailed
simulation
study
to
evaluate
the
Bayesian
model.
EPA
evaluated
the
performance
of
the
Bayesian
estimator
and
an
alternative
occurrence
estimation
approach,
the
Regression
on
Ordered
Statistics
(
ROS)
method,
against
synthetic
data
(
i.
e.,
data
developed
with
known
national
contaminant
occurrence
distributions).
This
simulation
study
also
enabled
an
explicit
evaluation
of
the
validity
of
the
assumption
of
a
log­
normal
distribution
of
the
data.
The
simulation
study
was
conducted
using
varying
conditions
of
a
correctly
and
incorrectly
specified
model,
and
synthetic
data
sets
developed
with
high
and
low
amounts
of
non­
detected
data.
The
study
findings
indicated
that
the
Bayesian
estimator
performed
well
at
estimating
the
distributions
of
contaminant
concentration
means
(
especially
in
the
upper
tails),
performed
better
than
the
alternate
approach
(
i.
e.,
the
ROS
method),
and
accurately
estimated
the
uncertainty
of
the
distributional
estimates.
The
Agency
believes
that
this
analysis
supports
the
validity
of
EPA's
analytical
approach.
The
Bayesian
model
was
tested
against
the
ROS
approach
because
the
ROS
method
is
an
accepted
drinking
water
contaminant
occurrence
estimation
approach
and
was
used
to
estimate
occurrence
for
the
recent
arsenic
rule.
These
findings
were
all
included
and
described
in
the
Six­
Year
Review's
Occurrence
Methodology
Document.
EPA
has
attempted
to
make
its
occurrence
analysis
as
clear
as
possible.
In
response
to
the
concerns
raised
by
the
peer
reviewers,
a
less
technical
description
of
the
occurrence
estimation
methodology,
aimed
at
the
general
reader,
was
added
to
the
main
body
of
the
document.
A
detailed
description
of
the
analysis,
intended
for
readers
with
technical
expertise,
including
the
complete
computer
code
used
for
model
analysis,
was
incorporated
into
an
appendix
of
the
document.
EPA
agrees
that
its
estimation
methodology
is
complex,
but
also
believes
that
it
is
as
transparent
as
possible
while
still
providing
a
technically
accurate
description
of
the
Agency's
analysis.
The
use
of
simple
national
occurrence
(
statistical)
assessments
is
not
possible
at
this
time
because
there
is
no
national
database
with
a
complete
collection
of
regulated
contaminant
occurrence
data.
Thus,
there
is
no
ideal
basis
for
comparison
of
national
occurrence
studies
(
i.
e.,
the
true
system
contaminant
means
and
national
distributions
of
contaminant
occurrence
are
not,
and
cannot,
be
known).
The
validation
approach
suggested
by
the
commenter
(
i.
e.,
basing
the
model
on
a
portion
of
the
data
set
and
using
the
remainder
to
test
the
model)
is
intended
for
a
regression­
type
of
model
using
observed
system
means
to
develop
a
model
for
system­
specific
predictions.
This
approach
is
not
possible
for
the
six­
year
occurrence
assessments,
since,
to
the
best
of
EPA's
knowledge,
data
on
the
true
individual
system
contaminant
mean
concentrations
and
national
distributions
are
not
available.
Regarding
the
other
survey
studies
included
in
the
Occurrence
Summary
Document,
few,
if
any,
provide
the
quantitative
analytical
results
and
national,
representative
coverage
that
would
enable
direct
comparison
to,
or
inclusion
in,
the
Six­
Year
Review
estimation
analyses
conducted
with
the
16­
State
cross­
section
occurrence
data.
c.
Other
Issues
Related
to
the
Occurrence
Technical
Review.
One
commenter
stated
that
the
Agency's
current
approach
to
estimate
occurrence,
employing
a
conservative
methodology
and
making
conservative
simplifying
assumptions
in
the
absence
of
definitive
data,
was
appropriate.
On
the
other
hand,
the
commenter
argued
that
it
was
not
appropriate
for
the
Agency
to
conduct
as
massive
a
data
collection
and
analysis
project
as
was
undertaken
without
clear
quantitative
objectives
for
the
analysis
identified
a
priori.
The
commenter
noted
that
it
was
not
apparent
from
either
the
April
17,
2002,
Federal
Register
or
the
Occurrence
Methodology
Document
(
USEPA,
2002e)
that
the
Agency
undertook
an
effort
to
set
performance
objectives
for
the
occurrence
estimation.
The
commenter
felt
that
the
Occurrence
Methodology
Document
does
not
allow
the
reader
to
determine
if
the
data
are
well
apportioned
among
the
categories
for
which
results
are
reported.
They
also
noted
that
they
were
unable
to
find
indications
in
the
support
document
that
such
an
analysis
was
undertaken
in
preparation
for
constructing
the
Bayesian
model.
The
commenter
stated
that
the
support
document
does
not
include
actual
numeric
counts
or
ranges
of
detected
values
and
suggested
that
it
would
be
useful
to
have
this
information
by
contaminant,
State,
system
size
category,
and
water
type,
as
well
as
an
explicit
count
of
non­
detects
by
this
same
matrix.
EPA
Response:
There
are
several
general
approaches
when
undertaking
and
designing
studies
that
require
large
amounts
of
data.
As
the
commenter
states,
a
priori
data
quality
objectives
are
part
of
one
research
approach
where
study
objectives
(
including
technical
statistical
performance
measures)
are
set,
determinations
are
made
on
how
to
meet
those
objectives,
and
then
the
study
is
designed
and
implemented
accordingly.
This
ideal
was
not
practical
for
the
national
occurrence
study
conducted
for
the
Six­
Year
Review
because
EPA
did
not
have
the
resources
to
generate
original
data,
and
was
thus
dependent
on
the
data
that
could
be
obtained
from
the
States.
The
approach
taken
by
the
Six­
Year
Review
was
to
gather
a
large
amount
of
data
that,
in
aggregate,
was
expected
to
be
indicative
of
national
contaminant
occurrence,
develop
an
occurrence
estimation
model
that
built
upon
what
has
been
learned
from
recent
regulatory
development
work,
and
then
evaluate
how
good
the
resulting
model
estimates
are.
As
discussed
in
section
IV.
A.
6.
b
of
today's
action,
the
true
national
distributions
of
contaminant
occurrence
cannot
be
known.
The
16­
State
national
cross­
section
data
set
used
for
the
Six­
Year
Review
is
the
largest
compliance
monitoring
database
for
drinking
water
compiled
by
EPA
to
date.
The
database
represents
approximately
37
percent
of
the
total
number
of
public
water
systems
and
43
percent
of
the
total
population
served
by
public
water
systems
in
the
United
States.
External
peer
reviews
assessed
the
approach
for
developing
the
national
cross­
section
and
its
``
representativeness''
separately
under
the
Chemical
Monitoring
Reform
(
CMR)
project
(
in
1998/
1999)
(
USEPA,
1999c)
and
the
Six­
Year
Review
project
(
USEPA,
2002e),
and
provided
generally
favorable
comments.
The
data
management
and
crosssection
development
have
been
described
in
detail
in
the
support
documents
for
the
CMR
and
the
Six­
Year
Review.
Further
tabulations
of
the
data
have
been
generated
and
presented,
as
the
commenter
requested,
in
the
final
Occurrence
Methodology
Document
(
USEPA,
2003d).
This
information
includes
the
numbers
and
percentages
of
analytical
detections
and
nondetections
for
each
contaminant
in
each
of
the
system
size
and
source
water
type
categories.
Generally,
because
of
the
large
amount
of
data
and
the
manner
in
which
the
Bayesian
model
handles
data,
the
distribution
of
observations
across
the
various
categories
does
not
significantly
affect
EPA's
estimates.
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Notices
2
These
15
chemical
NPDWRs
are:
Benzene;
beryllium;
chlordane;
1,2­
dibromo­
3­
chloroproppane
dichloromethane;
1,1­
dichloroethylene;
1,2­
dichloropropane;
heptachlor;
heptachlor,
epoxide;
hexachlorobenzene;
lindane;
oxamyl;
picloram;
toxaphene;
and
1,1,2­
trichloroethane.
3
The
other
three
NPDWRs
in
the
data
gaps
category,
chromium,
fluorida,
and
lead,
were
placed
there
for
reasons
other
than
occurrence
and
economic
considerations.
Chrominum
is
in
the
data
gaps
category
because
of
the
studies
being
conducted
by
the
National
Toxicology
Program
studies.
Fluoride
is
in
the
data
gaps
category
pending
a
National
Academy
of
Sciences
update
of
the
health
risk
assessment
and
review
of
the
RSC
assumptions.
Lead
is
in
the
data
gaps
category
based
on
consideration
of
public
comments
(
see
section
IV.
B.
13
of
today's
action).
number
of
analytical
records
differed
by
contaminant.
EPA
evaluated
27,648
to
93,062
analytical
records
for
the
individual
inorganic
chemicals,
32,606
to
121,327
records
for
the
synthetic
organic
chemicals,
and
123,229
to
201,235
records
for
the
volatile
organic
chemicals.
Most
importantly,
the
Stage
2
occurrence
model
also
quantifies
the
uncertainty
of
the
estimates
in
the
different
categories
of
system
size
and
source
water
type.
Hence,
the
statistical
significance
of
differences
in
occurrence
between
the
categories
can
be
easily
assessed.
However,
the
Agency
believes
it
is
more
appropriate
to
consider
the
universe
of
potentially
affected
systems
within
the
16­
State
cross­
section,
rather
than
individual
system
categories,
when
making
its
revise/
not
revise
decisions
as
part
of
the
Six­
Year
Review
process.

7.
Consideration
of
Available
Economic
Information
Some
commenters
stated
that,
while
the
Agency's
review
of
NPDWRs
was
generally
consistent
with
NDWAC
recommendations
to
EPA
(
NDWAC,
2000),
it
is
not
clear
how
the
Agency
took
economic
factors
into
account.
EPA
Response:
An
EPA
memorandum,
dated
March
18,
2002,
describes
the
Agency's
qualitative
evaluation
of
economic
factors
(
USEPA,
2002c).
This
memorandum
was
cited
in
the
April
17,
2002,
Federal
Register
and
is
available
in
the
docket
for
the
Six­
Year
Review
(
Docket
No.
OW
 
2002
 
0012).
It
notes
that
detailed
economic
analyses
were
not
deemed
by
the
Agency
to
be
necessary
to
support
its
decisions
of
whether
or
not
to
revise
a
particular
NPDWR.
Rather,
a
qualitative
assessment,
based
on
the
extent
of
occurrence
of
a
contaminant
at
the
MCL,
as
well
as
at
alternative
levels,
was
undertaken
to
inform
the
Agency's
judgment
about
whether
possible
changes
to
an
MCL
offered
a
meaningful
opportunity
for
health
risk
reduction
and/
or
cost­
savings
to
public
water
systems
and
their
customers.
EPA
has
conducted
this
assessment
for
15
of
the
chemical
NPDWRs
for
which
the
Agency
had
determined
that
a
potential
health
or
technological
basis
may
exist
for
considering
a
revision
to
the
MCLG/
MCL.
2
EPA
compared
the
estimated
occurrence
and
exposure
values
at
the
current
MCL
and
at
potentially
revised
regulatory
level(
s).
For
14
of
these
chemical
NPDWRs,
the
Agency's
assessment
showed
that
the
differences
were
small.
In
EPA's
judgment,
these
differences
are
unlikely
to
provide
a
meaningful
opportunity
for
health
risk
reduction
or
cost­
savings
to
public
water
systems
and
their
customers.
After
consideration
of
these
factors,
EPA
decided
that
any
revision
would
be
a
low
priority
activity
for
the
Agency,
and,
thus,
not
appropriate
to
revise
at
this
time
because
of:
Competing
workload
priorities;
the
administrative
costs
associated
with
rule
making;
and
the
burden
on
States
and
the
regulated
community
to
implement
any
regulatory
change
that
resulted.
In
the
case
of
dichloromethane,
the
Agency
did
not
have
sufficient
data
to
recalculate
the
PQL
to
support
any
potential
regulatory
revision
and
thus
placed
it
in
the
data
gaps
category.
3
B.
What
Comments
or
New
Information
Did
EPA
Receive
on
Chemical
Contaminant­
Specific
Issues?

1.
Alachlor
One
commenter
stated
that
the
Office
of
Pesticide
Programs
(
OPP)
found
that
the
chloroacetanilide
pesticides
(
acetochlor,
alachlor,
and
butachlor)
should
be
considered
as
a
group
of
chemicals
having
a
common
mechanism
of
toxicity
due
to
their
ability
to
cause
nasal
turbinate
tumors.
The
commenter
believes
EPA
therefore
should
adopt
a
strong
total
chloroacetanilide
pesticide
standard
that
would
strengthen
the
current
standards.
EPA
Response:
Butachlor
and
acetochlor
do
not
presently
have
an
NPDWR
and
thus,
are
not
included
in
the
Six­
Year
Review.
However,
acetochlor
is
included
on
the
Contaminant
Candidate
List
(
CCL)
and
may
in
the
future
be
considered
as
a
candidate
for
regulation.
Alachlor
is
a
regulated
drinking
water
contaminant
and
is
included
in
the
Six­
Year
Review.
It
is
currently
undergoing
a
risk
assessment
and,
therefore,
the
Agency
believes
that
revision
of
the
NPDWR
is
not
appropriate
at
this
time.
If
the
Agency
decides
to
regulate
either
acetochlor
or
butachlor
in
the
future,
EPA
may
consider
regulating
them
as
a
group,
including
alachlor,
following
a
cumulative
risk
assessment
process
for
pesticides
that
have
a
common
mechanism
of
toxicity.
It
would
be
premature
to
propose
a
total
chloroacetanilide
pesticide
standard
until
a
cumulative
risk
assessment
is
completed
because
this
analysis
could
impact
the
Agency's
evaluation
of
specific
members
of
this
group,
or
the
group
as
a
whole.

2.
Antimony
a.
Health
Effects.
A
number
of
commenters
have
suggested
that
the
current
MCLG
and
MCL
of
0.006
milligrams
per
liter
(
mg/
L)
for
antimony
need
to
be
revised.
Some
of
the
reasons
given
were:
 
The
study
used
to
derive
the
current
MCLG
(
Schroeder
et
al.,
1970)
is
not
consistent
with
current
good
laboratory
practice
guidelines
and
there
are
several
newer
studies
of
antimony
toxicity
that
should
be
considered
in
deriving
a
new
reference
dose
(
RfD).
 
Animals
used
in
the
Schroeder
et
al.,
1970
study
had
a
viral
infection.
To
compensate
for
this
infection,
adjustments
were
made
to
the
size
of
the
animal
groups
in
an
attempt
to
salvage
the
data.
 
The
antimony
compound
used
in
the
Schroeder
et
al.,
1970
study
was
potassium
antimony
tartrate,
the
most
water
soluble
and
toxic
form
of
antimony.
Antimony
found
in
drinking
water
is
likely
to
be
in
the
form
of
less
toxic
trivalent
and
pentavalent
antimony
species.
Therefore,
basing
the
MCLG
on
the
most
toxic
species
of
antimony
(
potassium
antimony
tartrate)
is
likely
to
overestimate
the
risk
posed
by
antimony
in
drinking
water.
EPA
Response:
EPA
agrees
that
the
MCLG
and
MCL
for
antimony
may
need
to
be
re­
evaluated.
EPA
is
in
the
process
of
developing
a
new
health
risk
assessment
for
antimony,
taking
into
consideration
new
studies
that
have
become
available
on
the
toxicity
of
antimony.
EPA
expects
to
complete
the
health
risk
assessment
for
antimony
in
the
2003
 
2004
time
frame
(
68
FR
5870,
February
5,
2003
(
USEPA,
2003h)).
As
a
result
of
the
ongoing
health
risk
assessment,
a
revision
to
the
antimony
standard
is
not
appropriate
at
this
time,
and
antimony
will
be
re­
evaluated
as
part
of
the
next
Six­
Year
Review
process.
b.
Treatment
and
Implementation
Issues.
Several
commenters
questioned
the
appropriateness
of
the
antimony
MCL,
and
the
effectiveness
of
using
the
EPA­
designated
best
available
technologies
(
BATs)
to
meet
the
antimony
MCL.
A
few
small
systems
in
Utah
have
levels
of
antimony
in
water
at
or
above
the
MCL
value
of
0.006
mg/
L.
These
systems
were
granted
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Notices
4
The
IRED
is
an
intermediate
decision
for
an
individual
pesticide
that
does
not
take
into
account
cumulative
risk
issues
for
pesticides
with
a
common
mode
of
action.
The
RED
does
include
cumulative
risk.
If
an
IRIS
assessment
is
also
in
process
when
the
IRED
or
RED
is
signed,
EPA
will
make
a
case­
by­
case
decision
on
whether
to
wait
for
the
IRIS
assessment
before
considering
possible
revisions
to
the
NPDWR.
5
Section
303(
d)
of
the
Clean
Water
Act
and
the
implementing
regulations
(
40
CFR
130.7)
require
States
to
develop
TMDLs
for
waters
where
required
point
and
nonpoint
source
pollution
controls
are
not
stringent
enough
to
attain
or
maintain
compliance
with
State
water
quality
standards
after
the
application
of
technology­
based
and
other
Continued
exemptions
contingent
upon
testing
and
installation
of
treatment
by
March
2004.
These
systems
are
investigating
treatment
options
for
the
removal
of
antimony
from
their
source
water.
Commenters
submitted
supporting
data
documenting
the
results
of
their
testing
and
cost
analyses.
According
to
commenters,
on­
site
testing
indicated
that
the
designated
BATs
(
i.
e.,
reverse
osmosis
and
coagulation/
filtration)
and
most
of
the
other
tested
treatments
were
ineffective
and/
or
prohibitively
expensive
due
to:
raw
water
quality
concerns;
water
conservation
needs;
current
costs
for
water
production;
and
other
concerns,
such
as
waste
water
management.
However,
commenters
did
identify
treatment
options
that
may
be
feasible,
but
these
may
require
further
investigation
prior
to
full
scale
use.
EPA
Response:
As
discussed
in
the
April
17,
2002,
Federal
Register
and
as
noted
in
the
previous
response
in
section
IV.
B.
2.
a,
EPA
does
not
believe
it
is
appropriate
to
consider
revisions
to
the
NPDWR
for
antimony
at
this
time
because
of
the
ongoing
health
risk
assessment
(
67
FR
19030
at
19051
(
USEPA,
2002g)).
When
EPA
initially
promulgated
the
antimony
NPDWR
in
1992,
the
Agency
estimated
that
200
public
water
systems
would
be
affected
(
USEPA,
1992).
EPA
recognizes
that
implementation
of
this
standard
may
present
challenges
for
a
few
localities.
Although
the
use
of
the
designated
BATs
for
antimony
may
not
be
appropriate
in
some
cases,
as
long
as
systems
comply
with
the
MCL,
they
are
not
limited
to
these
technologies.
EPA
believes
that
the
treatment
data
generated
by
the
commenters
may
be
valuable
and
may
provide
insight
into
potential
alternative
treatment
technologies.
The
Agency
has
revised
the
document,
``
Water
Treatment
Technology
Feasibility
Support
Document
for
Chemical
Contaminants;
In
support
of
EPA
Six­
Year
Review
of
National
Primary
Drinking
Water
Regulations''
(
Treatment
Feasibility
Document)
(
USEPA,
2003g)
to
refer
to
these
preliminary
test
data
as
they
may
be
applicable
to
the
development
of
potential
new
treatment
technologies
for
the
removal
of
antimony
and
other
contaminants.

3.
Atrazine
a.
Health
Effects.
Several
commenters
addressed
the
EPA
decision
not
to
consider
revision
of
the
MCL
for
atrazine
at
this
time.
Some
of
these
commenters
stated
that
EPA
should
use
the
risk
assessment,
released
by
OPP
in
May
2002,
as
a
basis
for
reconsidering
the
atrazine
NPDWR.
One
of
the
commenters
noted
that
the
2002
risk
assessment
is
based
on
reproductive
and
developmental
endpoints
which
represents
a
change
from
the
toxicity
endpoint
that
formed
the
basis
of
the
current
MCLG.
Two
commenters
stated
that
the
MCL
for
atrazine
should
be
revised
upward
because
of
the
results
of
the
2002
OPP
risk
assessment
in
which
the
RfD
increased
and
the
cancer
classification
changed
from
``
possible
human
carcinogen''
to
``
not
likely
to
be
a
human
carcinogen.''
The
commenters
stated
that
the
change
in
the
cancer
assessment
implies
elimination
of
the
additional
10­
fold
risk
management
factor
used
in
1991
to
derive
the
MCLG/
MCL
for
atrazine.
Another
commenter
stated
that
atrazine
should
be
regulated
using
a
non­
linear
approach
which
recognizes
that
there
is
a
level
at
which
no
known
health
effects
occur
and
that
these
findings
must
be
part
of
the
new
MCL.
Conversely,
another
commenter
stated
that
there
is
substantial
new
evidence
from
epidemiological
and
occupational
studies
that
atrazine
poses
a
serious
cancer
risk,
and
that
it
is
an
endocrine
disruptor
at
low
levels.
The
commenter
believes
EPA
should
adopt
a
revised
atrazine
and
total
triazine
standard
lower
than
(
i.
e.,
more
stringent
than)
the
current
0.003
mg/
L
standard
for
atrazine.
A
commenter
also
urged
the
Agency
to:
 
Provide
a
definitive
timetable
for
review
of
the
standard;
 
Outline
a
preliminary
scope
for
its
review
of
the
standard;
and
 
State
the
underlying
premise
for
the
scope
of
the
review.
Other
commenters
stated
that
the
existing
NPDWR
only
regulates
the
parent
compound
atrazine,
and
that
a
revised
NPDWR
should
include
the
chloro­
metabolite
degradants
(
i.
e.,
diaminochlorotriazine
(
DACT),
desethyl
atrazine
(
DEA),
and
desisopropyl
atrazine
(
DIA)).
These
commenters
believe
that
inclusion
of
the
chlorometabolites
would
strengthen
compliance
monitoring
programs
for
public
water
systems
under
SDWA
and
thereby
strengthen
public
health
protection.
They
stated
that
a
regulation
for
atrazine
and
the
chloro­
metabolites
should
be
developed
and
promulgated
within
the
next
12
to
18
months.
Another
commenter
stated
that
since
the
Agency
has
found
that
atrazine,
simazine,
propazine,
and
the
degradants
DACT,
DEA,
and
DIA
have
a
common
mechanism
of
toxicity,
these
should
be
regulated
in
a
total
triazine
regulation.
EPA
Response:
EPA
does
not
believe
it
is
appropriate
to
consider
revisions
to
the
NPDWR
for
atrazine
at
this
time
because
the
revised
risk
assessment
has
not
been
finalized.
For
purposes
of
the
Six­
Year
Review
protocol,
EPA
considers
a
risk
assessment
final
when
an
Interim
Reregistration
Eligibility
Decision
(
IRED),
Reregistration
Eligibility
Decision
(
RED),
and/
or
IRIS
assessments
are
complete.
4
Even
though
an
IRED
for
atrazine
was
signed
on
January
31,
2003,
an
amended
IRED
is
scheduled
to
be
released
in
October
2003
which
will
include
a
Scientific
Advisory
Panel
(
SAP)
peer
review
of
new
data
related
to
health
effects.
Based
upon
the
outcome
of
the
SAP
review,
the
October
2003
IRED
may
include
additional
information
that
could
impact
a
revise/
not
revise
decision.
Therefore,
EPA
does
not
believe
it
is
appropriate
to
consider
possible
revisions
to
the
NPDWR
at
this
time.
In
reviewing
the
atrazine
regulation,
EPA
will
apply
an
approach
consistent
with
the
protocol
used
for
the
current
review.
The
Agency
will
consider
the
same
key
elements
(
i.
e.,
health
effects
review,
technology
review,
other
regulatory
revisions
review,
and,
if
appropriate,
occurrence/
exposure
analyses
and
consideration
of
available
economic
information)
and
apply
the
same
basic
decision
tree
for
making
a
revise/
not
revise
decision.
To
address
the
issue
of
regulating
the
triazines
as
a
group,
the
Agency
is
evaluating
the
unregulated
triazines
as
part
of
the
CCL
process.
When
the
risk
assessment
is
completed
for
atrazine,
the
Agency
will
consider
whether
or
not
there
are
compelling
reasons
for
considering
a
revision
to
the
atrazine
regulation
or
to
wait
until
the
risk
assessment
for
the
triazines,
which
considers
issues
of
cumulative
risk,
is
finalized.
EPA
will
use
the
CCL
regulatory
determination
process
in
deciding
whether
the
triazines
should
be
regulated
as
a
group.
b.
Costs
of
Treatment.
Commenters
stated
that
the
costs
associated
with
not
revising
the
MCL
are
great.
These
commenters
are
concerned
that
State
agencies
will
be
required
to
develop
total
maximum
daily
loads
(
TMDLs)
based
on
303(
d)
5
listings
resulting
from
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required
controls.
A
TMDL
establishes
the
maximum
amount
of
a
pollutant
that
may
be
introduced
into
a
waterbody
while
still
ensuring
attainment
and
maintenance
of
water
quality
standards.
6
Since
NTP
is
posting
its
progress
on
its
internet
site
http://
ntp­
server.
niehs.
nih.
gov/
htdocs/
Studies/
HexChromium/
hexchromiumpg.
html,
EPA
and
the
public
will
be
able
to
evaluate
the
new
data
relative
to
the
existing
EPA
assessment
for
chromium
VI
as
it
is
released.
an
outdated
MCL
which
creates
a
burden
on
State
and
local
government,
its
citizens,
and
diverts
limited
resources
away
from
programs
that
provide
real
benefits.
Some
commenters
also
stated
that
the
treatment
costs
to
hundreds
of
community
water
systems
are
considerable.
One
commenter
also
stated
that
these
are
real
dollars
that
would
otherwise
be
available
for
emergency
services,
education,
nutrition
programs,
and
other
vital
programs
that
are
the
responsibilities
of
local
and
State
agencies.
EPA
Response:
As
stated
in
the
previous
response
in
section
IV.
B.
3.
a,
EPA
does
not
believe
it
is
appropriate
to
revise
the
NPDWR
for
atrazine
at
this
time
because
the
risk
assessment
is
not
yet
final.
If
EPA
decides
to
revise
the
NPDWR
for
atrazine,
economic
factors,
including
feasibility
and
an
assessment
of
costs
and
benefits,
will
be
taken
into
consideration
for
the
drinking
water
program.

4.
Beryllium
Two
commenters
believed
that
the
current
drinking
water
standard
for
beryllium
is
more
stringent
than
necessary
for
the
protection
of
public
health
and
felt
that
EPA
should
adopt
a
higher
value
for
the
beryllium
standard.
These
commenters
disagreed
with
EPA
on
the
use
of
an
uncertainty
factor
of
300
in
deriving
the
1998
RfD.
The
commenters
stated
the
use
of
uncertainty
factors
of
3
for
database
uncertainty,
10
for
extrapolating
data
from
a
dog
study
to
humans,
and
10
for
intraspecies
variation
is
inappropriate.
The
commenters
stated
that
EPA
has
the
authority
to
raise
the
current
drinking
water
standards
for
beryllium
based
on
new
information
that
allows
for
a
smaller
margin
of
safety
than
the
one
used
by
EPA.
The
commenter
felt
that
the
current
standard
for
beryllium
is
``
lower
than
necessary
to
protect
the
public
from
beryllium
toxicity
and
results
in
clean­
up
standards
that
are
lower
than
naturally
occurring
level
of
beryllium
in
water
sources
and
soils.''
This
commenter
also
expressed
concern
that
the
local
application
of
the
Federal
drinking
water
standard
to
private
wells
in
some
cases
caused
undue
concerns
among
users
of
those
wells.
EPA
Response:
One
of
the
purposes
of
the
Six­
Year
Review
is
to
determine
if
the
MCL
of
a
chemical
should
be
changed
based
on
a
revised
RfD
or
cancer
classification.
Analytical
methods
and
treatment
technologies
are
considered,
as
well
as
occurrence
in
public
water
systems.
The
RfD
for
beryllium
was
revised
in
1998
based
on
extensive
Agency
internal
and
external
reviews,
and
is
unlikely
to
be
revised
in
the
absence
of
new
data.
The
1998
assessment
also
provided
separate
cancer
classification
for
inhalation
and
oral
exposures
(
USEPA,
1998).
In
the
revised
assessment,
the
carcinogenicity
of
beryllium
by
the
inhalation
route
was
described
as
``
likely,''
while
that
by
the
oral
route
of
exposure
``
cannot
be
determined.''
As
discussed
in
the
April
17,
2002,
Federal
Register,
the
Agency
considered
the
occurrence
of
beryllium
at
both
potentially
higher
and
lower
regulatory
levels.
EPA
concluded
that
a
revision
to
the
NPDWR
would
not
result
in
a
meaningful
opportunity
for
health
risk
reduction
or
cost­
savings
to
public
water
systems
and
their
customers.
As
a
result,
revision
of
this
NPDWR
is
a
low
priority
action
for
the
Agency
and
is
not
appropriate
at
this
time.
The
goal
of
drinking
water
standards
is
to
protect
public
health.
Therefore,
it
does
not
matter
whether
the
source
of
contamination
is
naturally­
occurring
or
man­
made.
While
EPA
appreciates
the
information
on
private
wells,
the
SDWA
requirements
do
not
apply
to
private
wells
(
i.
e.,
wells
that
are
not
part
of
a
``
public
water
system'').
The
costs
and
benefits
of
a
drinking
water
standard
are
assessed
only
with
regard
to
the
impacts
on
public
water
systems
and
their
customers.

5.
Carbofuran
Some
commenters
mentioned
that
the
Agency
concluded
that
N­
methyl
carbamates,
including
carbofuran,
should
be
considered
as
a
class
because
they
have
a
common
mechanism
of
toxicity.
Therefore,
they
believe
EPA
should
issue
a
stronger
standard
for
total
N­
methyl
carbamates,
including
carbofuran,
which
would
be
more
stringent
than
the
current
carbofuran
standard
of
0.04
mg/
L.
EPA
Response:
EPA
is
re­
evaluating
the
toxicity
of
carbofuran.
However,
a
final
assessment
has
not
been
issued
by
EPA.
The
Agency
considers
N­
methyl
carbamate
pesticides
as
a
group
of
chemicals
having
a
common
mechanism
of
toxicity
due
to
their
ability
to
inhibit
acetylcholinesterase.
However,
it
is
not
appropriate
to
revise
the
NPDWR
for
carbofuran
at
this
time
because
the
Agency
has
not
yet
completed
the
final
health
risk
assessment
for
carbofuran
or
the
other
N­
methyl
carbamates.

6.
Chromium
One
commenter
requested
that
EPA
move
quickly
in
making
a
revise/
not
revise
determination
once
the
new
data
on
chromium
become
available
from
the
National
Toxicology
Program
(
NTP)
studies
of
the
health
effects
of
chromium
VI.
EPA
Response:
The
NTP
studies
that
the
commenter
refers
to
should
be
available
before
the
end
of
the
next
Six­
Year
Review
cycle.
Meanwhile,
EPA
is
continuing
to
follow
the
progress
of
NTP
in
conducting
subchronic
and
chronic
studies
of
chromium
VI.
6
NTP
made
the
data
from
the
subchronic
portion
of
the
study
available
to
the
public
in
June
2002
(
NTP,
2002).
A
peer
review
meeting
was
held
at
NTP
on
July
24,
2002.
EPA
will
examine
the
peer
review
report
covering
the
subchronic
data
once
it
becomes
available.
Once
the
subchronic
and
chronic
studies
are
completed,
the
health
effects
data
will
be
evaluated
with
regard
to
their
impact
on
the
present
RfD
and
cancer
assessment,
and
integrated
with
the
occurrence
and
analytical
method
data
before
making
a
new
revise/
not
revise
decision.

7.
1,1­
Dichloroethylene
In
the
April
17,
2002,
Federal
Register,
the
Agency
preliminarily
placed
1,1­
dichloroethylene
in
the
no
revision
category
because
a
health
risk
assessment
was
pending
at
the
time
of
publication.
Since
the
publication
of
the
April
17,
2002,
Federal
Register,
the
Agency
has
finalized
the
risk
assessment
for
1,1­
dichloroethylene.
The
remaining
paragraphs
in
this
section
include
a
brief
background
discussion
about
the
original
promulgation
of
the
1,1­
dichloroethylene
NPDWR,
the
results
of
the
appropriate
six­
year
technical
reviews
and
the
Agency's
revise/
not
revise
decision.
a.
Background.
EPA
published
the
current
NPDWR
for
1,1­
dichloroethylene
on
July
8,
1987
(
52
FR
25690
(
USEPA,
1987)).
The
NPDWR
established
an
MCLG
and
an
MCL
of
0.007
mg/
L.
The
Agency
based
the
MCLG
on
an
RfD
of
0.009
milligram
per
kilogram
of
body
weight
per
day
(
mg/
kg/
day)
and
a
cancer
classification
of
C,
possible
human
carcinogen.
b.
Technical
Reviews.
EPA
updated
the
risk
assessment
for
1,1­
dichloroethylene
on
August
13,
2002
(
USEPA,
2002i).
The
new
risk
assessment
established
an
RfD
of
0.046
mg/
kg/
day,
based
on
the
same
toxicological
study
as
that
of
the
MCLG,
but
using
an
uncertainty
factor
of
100
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instead
of
1,000,
and
using
benchmark
dose
modeling
for
the
dose­
response
analysis.
Under
the
1986
cancer
guidelines
(
51
FR
33992,
September
24,
1986
(
USEPA,
1986)),
1,1­
dichloroethylene
was
assigned
to
Group
C,
possible
human
carcinogen.
Under
the
draft
revised
``
Guidelines
for
Carcinogen
Risk
Assessment''
(
USEPA,
1999a),
the
data
for
1,1­
dichloroethylene
were
considered
inadequate
for
an
assessment
of
human
carcinogenic
potential
by
the
oral
route.
Based
on
the
change
in
RfD
for
1,1­
dichloroethylene,
using
a
20
percent
RSC
and
a
10­
fold
risk
management
factor
for
possible
carcinogenicity,
EPA
used
0.03
mg/
L
as
a
level
for
evaluating
the
occurrence
data.
Without
the
use
of
the
10­
fold
risk
management
factor,
EPA
also
used
0.3
mg/
L
as
a
level
for
evaluating
the
occurrence
data.
Analytical
or
treatment
feasibility
do
not
pose
any
limitations
for
the
current
MCL
and
would
not
be
a
limiting
factor
at
the
0.03
mg/
L
or
the
0.3
mg/
L
level
(
USEPA,
2002a;
USEPA,
2003g).
The
Agency's
review
of
possible
``
other
regulatory
revisions''
did
not
identify
any
issues
that
are
specific
to
1,1­
dichloroethylene
(
USEPA,
2003b).
EPA
evaluated
the
results
of
the
occurrence
and
exposure
analyses
for
1,1­
dichloroethylene
to
determine
whether
possible
changes
to
the
standard
would
be
likely
to
result
in
a
meaningful
opportunity
for
cost­
savings
to
public
water
systems
and
their
customers
(
USEPA,
2003d).
Table
IV
 
1
shows
the
results
of
the
detailed
occurrence
and
exposure
analysis
based
on
the
16­
State
cross­
section
for
the
current
MCL
(
0.007
mg/
L),
and
for
two
higher
levels
(
0.03
mg/
L
and
0.3
mg/
L).
Based
on
the
detailed
analysis,
it
appears
that
1,1­
dichloroethylene
is
unlikely
to
occur
at
concentrations
above
0.007
mg/
L
in
the
States
used
for
the
cross­
section.

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The
results
of
the
detailed
occurrence
and
exposure
analysis
indicate
that
less
than
0.02
percent
of
the
19,101
systems
sampled
in
the
16­
State
cross­
section,
and
less
than
0.02
percent
of
the
population
served
by
those
19,101
systems
might
be
affected
if
EPA
were
to
consider
levels
as
high
as
0.03
mg/
L
to
0.3
mg/
L.
The
current
BATs
and
small
system
compliance
technology
for
1,1­
dichloroethylene
have
other
beneficial
effects
(
e.
g.,
reduction
of
other
co­
occurring
contaminants,
or
other
common
impurities)
in
addition
to
1,1­
dichloroethylene
removal.
Therefore,
if
EPA
were
to
consider
any
of
these
higher
levels,
the
Agency
does
not
know
how
many
of
these
public
water
systems
that
are
currently
treating
to
comply
with
the
current
MCL
of
0.007
mg/
L
would
be
likely
to
discontinue
treatment
that
is
already
in
place
(
USEPA,
2002c;
USEPA,
2003g).
c.
Current
Decision.
Although
there
are
new
health
effects
data
that
might
support
calculation
of
a
less
stringent
standard
for
1,1­
dichloroethylene,
EPA
does
not
believe
a
revision
to
the
NPDWR
for
1,1­
dichloroethylene
is
appropriate
at
this
time.
In
making
this
decision,
the
Agency
considered
whether
any
potential
revision
to
the
1,1­
dichloroethylene
NPDWR
is
likely
to
provide
a
meaningful
opportunity
for
cost­
savings
to
public
water
systems
and
their
customers.
After
consideration
of
this
factor,
EPA
has
decided
that
any
revision
to
1,1­
dichloroethylene
would
be
a
low
priority
activity
for
the
Agency,
and,
thus,
is
not
appropriate
to
revise
at
this
time
because
of:
 
Competing
workload
priorities;
 
The
administrative
costs
associated
with
rulemaking;
and
 
The
burden
on
States
and
the
regulated
community
to
implement
any
regulatory
change
that
resulted.

8.
Dichloromethane
One
commenter
stated
that
it
may
be
difficult
to
lower
the
PQL
for
dichloromethane
below
the
range
of
0.001
to
0.002
mg/
L
since
it
is
required
in
a
number
of
EPA
methods
and
therefore
is
a
common
laboratory
contaminant.
Because
it
is
a
common
laboratory
contaminant,
the
commenter
stated
that
using
the
MDL
for
524.2
and
502.2
does
not
constitute
a
reasonable
basis
for
assuming
that
the
PQL
can
be
lower.
The
commenter
stated
that
none
of
the
existing
WS
studies
had
spike
samples
this
low
and,
in
addition,
the
occurrence
data
may
have
been
compromised
due
to
laboratory
contamination.
EPA
Response:
The
basis
for
EPA
indicating
that
a
lower
PQL
``
may
exist''
was
due
to
the
fact
that
laboratories
had
greater
than
95
percent
laboratory
passing
rates
using
a
+/
¥
40
percent
acceptance
window
at
``
known''
spike
concentrations
close
to
current
MCL
of
0.005
mg/
L.
If
laboratory
contamination
due
to
dichloromethane
were
a
problem,
such
high
passing
rates
at
this
value
would
not
be
expected.
The
MDLs
for
524.2
and
502.2
were
only
used
with
the
10
times
MDL
multiplier
to
estimate
what
the
lower
value
could
be.
However,
EPA
does
agree
that,
at
this
time,
the
Agency
does
not
have
sufficient
data
to
recalculate
the
PQL
for
dichloromethane
and
for
this
reason,
the
Agency
placed
it
in
the
data
gap
category.
Regarding
the
occurrence
issue,
EPA
has
no
data
to
suggest
that
high
occurrence
values
were
due
to
false
positives
from
laboratory
contamination
and
the
Agency
is
proceeding
on
the
assumption
that
State
data
are
accurate
unless
there
is
information
to
the
contrary.
If
laboratory
contamination
due
to
dichloromethane
does
exist,
laboratories
should
be
able
to
identify
and
discern
a
contamination
issue
if
they
are
running
laboratory
blanks.

9.
Di(
2­
ethylhexyl)
adipate
(
DEHA)
One
commenter
submitted
detailed
comments
regarding
di(
2­
ethylhexyl)
adipate
(
DEHA).
The
commenter
believed
that
EPA
should
consider
removing
the
regulation
for
DEHA
and
provided
the
following
reasons:
 
The
regulation
of
DEHA
in
drinking
water
does
not
provide
any
meaningful
reduction
in
the
health
risk
to
humans
because
it
is
unlikely
to
cause
adverse
effects
to
humans,
including
reproductive
effects,
except
at
very
high
doses
which
cannot
be
attained
in
drinking
water,
due
to
the
low
water
solubility
of
DEHA.
 
The
weight
of
evidence
indicates
that
the
peroxisome
proliferation
mechanism
of
DEHA
rodent
carcinogenicity
is
not
relevant
to
humans.
Thus,
the
MCLG
for
DEHA
should
not
include
an
additional
10­
fold
risk
management
factor
for
possible
carcinogenicity.
 
The
legislative
history
of
the
1996
SDWA
indicates
that
Congress
envisioned
circumstances
where
relaxation
of
an
MCL
would
provide
the
same
level
of
health
protection
as
the
existing
regulation.
Accordingly,
if
DEHA
cannot
be
deregulated,
the
commenter
believes
the
MCLG
and
MCL
should
be
increased.
EPA
Response:
DEHA
was
regulated
in
1992.
Since
that
time,
new
studies
have
become
available
on
the
toxicity
of
DEHA
and
its
metabolites.
For
this
reason,
EPA
decided
to
initiate
a
new
health
risk
assessment
of
DEHA
(
67
FR
1212,
January
9,
2002
(
USEPA,
2002a)).
The
assessment
will
include
examination
of
the
studies
on
which
the
current
NPDWR
is
based,
as
well
as
an
evaluation
of
the
data
provided
by
this
commenter
and
new
studies
that
have
become
available
since
DEHA
was
regulated.
This
health
risk
assessment
is
planned
for
completion
in
the
2003
 
2004
time
frame
(
68
FR
5870,
February
5,
2003
(
USEPA,
2003h))
and
is
expected
to
include
development
of
an
RfD
for
non­
cancer
health
effects,
as
well
as
an
assessment
of
potential
carcinogenicity
from
oral
exposure.
At
this
time,
it
is
premature
to
predict
the
outcome
of
the
Agency's
assessment.
Thus,
as
discussed
in
section
IV.
A.
2.
a
of
today's
action,
the
Agency
believes
that
revision
to
the
NPDWR
for
DEHA
is
not
appropriate
at
this
time.
EPA
will
determine
in
the
future
if
revision
of
the
MCLG/
MCL
is
warranted.
Any
revision
to
the
MCLG/
MCL
will
also
take
into
consideration
all
the
new
information,
including
the
water
solubility
of
DEHA
under
various
environmental
conditions.
As
stated
by
the
commenter,
the
legislative
history
of
the
1996
SDWA
Amendments
supports
EPA's
interpretation
that
the
Agency
could
increase
an
MCLG
and
MCL
as
long
as
the
relaxed
standard
does
not
lessen
the
level
of
public
health
protection.
However,
EPA
does
not
believe,
at
the
present
time,
that
it
can
demonstrate
that
deregulating
DEHA
would
maintain
the
current
level
of
public
health
protection
(
see
section
IV.
A.
1.
c
of
today's
action).

10.
Di(
2­
ethylhexyl)
phthalate
(
DEHP)

The
same
commenter
who
submitted
comments
on
DEHA
also
submitted
detailed
comments
regarding
di(
2­
ethylhexyl)
phthalate
(
DEHP).
The
commenter
felt
that
EPA
should
consider
removing
the
regulation
for
DEHP
for
a
variety
of
reasons,
including
the
following:
 
The
regulation
of
DEHP
in
drinking
water
does
not
provide
any
meaningful
reduction
in
the
health
risk
to
humans.
 
The
weight
of
the
evidence
indicates
that
the
mode
of
action
through
which
DEHP
causes
cancer
in
rodents
is
not
relevant
to
humans
and,
thus,
the
MCLG
for
DEHP
should
not
be
zero.
Any
MCLG
for
DEHP
should
be
based
on
a
threshold
endpoint
and
not
on
cancer.
The
commenter
cited
the
February
2000
International
Agency
for
Research
on
Cancer
reclassification
of
DEHP
from
Group
2B
(
possibly
carcinogenic
to
humans)
to
Group
3
(
not
classifiable
as
to
its
carcinogenicity
to
humans)
as
justification
for
recommending
that
EPA
also
reconsider
its
cancer
classification.

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The
solubility
of
DEHP
in
drinking
water
is
well
below
any
concentrations
that
would
pose
a
risk
to
humans.
 
If
DEHP
were
to
be
considered
for
regulation
under
the
statutory
requirements
of
the
1996
SDWA,
it
would
not
be
regulated.
 
The
legislative
history
of
the
1996
SDWA
indicates
that
Congress
envisioned
circumstances
where
relaxation
of
an
MCL
would
provide
the
same
level
of
health
protection
as
the
existing
regulation.
Accordingly,
the
commenter
believes
consideration
should
be
given
to
increasing
the
MCLG
for
DEHP
based
on
the
new
health
effects
data.
 
Reproductive
effects
from
DEHP
as
observed
in
rodents
do
not
appear
to
be
relevant
for
primates
and
the
doses
that
are
associated
with
effects
in
animals
are
well
above
those
that
would
be
experienced
for
humans
exposed
through
drinking
water
because
of
solubility
limitations.
The
commenter
also
highlighted
the
findings
of
the
NTP
Center
for
the
Evaluation
of
Risk
to
Human
Reproduction
that
there
was
``
minimal
concern
for
reproductive
or
developmental
toxicity
for
the
general
population,
based
on
estimates
of
total
exposure
to
DEHP.''
EPA
Response:
Revision
of
the
NPDWR
for
DEHP
is
not
appropriate
at
this
time
because
an
Agency
health
risk
assessment
is
currently
in
process.
The
assessment
is
anticipated
to
be
completed
in
the
2003
 
2004
time
frame
(
68
FR
5870,
February
5,
2003
(
USEPA,
2003h)).
Advances
in
understanding
differences
between
the
primate
and
rodent
response
to
DEHP
and
the
body
of
toxicological
data
that
have
become
available
in
the
past
decade
motivated
the
Agency's
re­
examination
of
DEHP
and
will
be
fully
considered
in
the
reassessment.
Once
the
Agency
assessment
is
completed,
EPA
will
consider
the
findings
and
will
determine
if
there
is
a
compelling
reason
to
review
the
DEHP
NPDWR
prior
to
the
next
Six­
Year
Review
cycle.
As
discussed
in
sections
IV.
A.
1.
b
and
IV.
A.
2.
a
of
today's
action,
``
revise''
versus
``
not
revise''
decisions
under
the
Six­
Year
Review
take
into
consideration
occurrence,
advances
in
analytical
methods,
treatment
technologies,
available
economic
information,
and
other
factors.
As
stated
by
the
commenter,
the
legislative
history
of
the
1996
SDWA
Amendments
supports
EPA's
interpretation
that
the
Agency
could
increase
an
MCLG
and
MCL
as
long
as
the
relaxed
standard
does
not
lessen
the
level
of
public
health
protection.
However,
EPA
does
not
believe,
at
the
present
time,
that
it
can
demonstrate
that
deregulating
DEHP
would
maintain
the
current
level
of
public
health
protection
(
see
section
IV.
A.
1.
c
of
today's
action).

11.
Fluoride
EPA
received
three
comments
on
the
Agency's
decision
to
place
fluoride
in
the
data
gap
category
while
the
National
Academy
of
Sciences
(
NAS)
examines
the
toxicological
and
RSC
data
published
over
the
last
decade.
Two
of
the
commenters
supported
EPA's
decision.
One
of
these
requested
that
the
NAS
concentrate
its
review
on
all
of
the
data
on
the
toxicology
of
fluoride
and
not
just
data
on
the
critical
skeletal
effects.
A
third
commenter
requested
that
EPA
not
lower
the
MCL
for
fluoride
from
4
mg/
L
to
2
mg/
L
and
supported
the
1986
EPA
decision
that
dental
fluorosis
is
a
cosmetic
effect
rather
than
an
adverse
health
effect.
The
commenter
stated
that
the
Public
Health
Service
(
PHS)
recommended
fluoridation
level
to
be
used
at
schools
is
3
mg/
L.
The
commenter
also
stated
that
if
EPA
were
to
lower
the
MCL,
then
schools
that
are
currently
fluoridating
might
have
a
conflict
with
the
PHS
recommendations
and
the
EPA
MCL.
EPA
Response:
The
National
Research
Council
(
NRC)
of
the
NAS
has
agreed
to
review
the
toxicological
data
on
fluoride
that
have
been
published
since
it
completed
the
1993
study
of
``
Health
Effects
of
Ingested
Fluoride''
(
NRC,
1993),
and
to
examine
the
data
on
relative
fluoride
exposure
from
drinking
water
compared
to
fluoride
exposure
from
the
diet
and
fluoride­
containing
dental
products.
Although
the
Agency
indicated
in
the
April
17,
2002,
Federal
Register
that
new
data
on
bone
effects
were
a
reason
for
initiating
the
data
review
(
because
bone
effects
were
the
basis
of
the
present
MCLG),
the
NAS
review
will
look
at
the
new
toxicological
data
for
all
endpoints.
It
is
anticipated
that
the
NAS
review
will
take
about
two
years
to
complete.
Because
of
this
pending
review,
revision
of
the
NPDWR
for
fluoride
is
not
appropriate
at
this
time.
It
is
therefore
premature
to
make
any
judgment
regarding
the
NAS
findings
and
whether
or
not
they
may
lead
to
a
consideration
of
a
change
in
the
MCL.
However,
PHS
recommendations
for
school
fluoridation
programs
are
designed
to
provide
the
benefits
of
fluoridation
without
increasing
the
risk
for
dental
fluorosis.
The
PHS
recommends
school
water
fluoridation
only
if:
 
The
school
has
its
own
source
of
water;
 
The
school
is
not
connected
to
a
community
water
system;
 
More
than
25
percent
of
students
are
not
served
by
a
public
water
system
that
provides
water
at
levels
adequate
to
protect
against
dental
caries;
and
 
The
students
served
are
kindergarten
age
or
greater.

12.
Glyphosate
Two
commenters
made
the
statement
that,
despite
continued
use
of
glyphosate
in
pesticide
applications,
available
data
and
the
Agency's
occurrence
analysis,
which
includes
a
prediction
of
frequency
of
occurrence
at
levels
below
detection,
indicate
that
glyphosate
is
not
observed
in
compliance
monitoring.
One
of
these
commenters
stated
that
the
occurrence
appeared
to
be
rare
(
less
than
0.1
percent)
at
concentrations
1,000
times
lower
than
the
MCL.
In
addition,
according
to
the
commenters,
the
cost
of
analyzing
for
glyphosate
is
expensive,
since
it
is
a
single
analyte
analysis.
Accordingly,
the
commenters
wanted
EPA
to
reconsider
the
glyphosate
standard
taking
costs
and
benefits
into
account.
The
commenters
felt
that
the
data
may
indicate
that
a
glyphosate
standard
is
inappropriate
and
does
not
result
in
any
additional
public
health
protection.
Therefore,
the
commenters
recommended
EPA
pursue
data
gaps
that
the
Agency
would
need
to
fill
in
order
to
demonstrate
that
eliminating
the
glyphosate
standard
would
not
lower
public
health
protection.
EPA
Response:
EPA
is
conducting
an
Agency
risk
assessment
for
glyphosate
that
will
update
the
1993
OPP
assessment.
As
a
part
of
this
process,
EPA
is
considering
all
the
data
that
have
been
published
or
submitted
to
EPA
since
the
completion
of
the
RED
in
1993
(
USEPA,
1993).
Accordingly,
revision
of
the
glyphosate
NPDWR
is
not
appropriate
at
this
time
due
to
the
pending
Agency
assessment.
EPA
recognizes
that
some
utilities
feel
that
the
analysis
of
glyphosate
in
drinking
water
is
expensive
and
that
this
should
be
taken
into
consideration
with
respect
to
cost
and
benefits.
This
will
be
considered
when
EPA
evaluates
glyphosate
in
the
next
review
cycle
(
unless
there
is
a
compelling
reason
to
evaluate
glyphosate
on
an
accelerated
schedule).
For
the
reasons
stated
in
section
IV.
A.
1.
c
of
today's
action,
EPA
does
not
believe
it
is
appropriate
to
consider
deregulation
of
glyphosate
at
this
time.

13.
Lead
and
Copper
a.
Research
Needs.
Three
commenters
acknowledged
the
Agency's
January
2000
revisions
to
the
Lead
and
Copper
Rule
(
LCR)
but
stated
that
the
Agency
should
continue
to
consider
how
to
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make
the
LCR
easier
to
implement.
In
particular,
they
recommended
that
the
following
three
LCR­
related
research
areas
be
incorporated
into
EPA's
overall
research
strategy:
1.
How
well
LCR
monitoring
results
correlate
to
actual
exposure
and
the
effectiveness
of
the
rule
in
protecting
public
health.
2.
Whether
there
is
a
correlation
between
water
quality
at
indoor
and
outdoor
taps.
3.
What
effect
the
ban
on
lead
in
fixtures
has
had
on
lead
levels
and
whether
changes
need
to
be
made
based
on
this
ban.
The
commenters
explained
their
rationale
for
recommending
that
the
Agency
determine
if
a
correlation
could
be
established
between
indoor
and
outdoor
water
quality.
They
stated
that
a
major
weakness
of
the
LCR
is
that
sample
integrity
may
be
compromised
by
allowing
customers
to
collect
water
samples.
If
the
Agency
could
establish
such
a
correlation,
the
LCR
could
be
revised
to
allow
water
system
operators
to
collect
samples
from
outdoor
taps;
thereby
removing
the
need
for
customercollected
sampling.
EPA
Response:
EPA
recognizes
that
the
LCR
is
a
challenging
rule
that
requires
difficult
solutions
to
implement,
but
continues
to
believe
that
the
public
health
objective
addressed
by
the
rule
is
as
important
and
essential
today
as
it
was
when
the
rule
was
first
promulgated.
Since
the
Agency
promulgated
the
revisions
to
the
LCR
in
January
2000
(
65
FR
1950,
January
12,
2000
(
USEPA,
2000)),
the
Agency
has
received
no
significant
new
information
that
would
support
a
revision.
However,
the
Agency
recognizes
that
more
research
would
be
useful
to
obtain
additional
information
that
could
be
utilized
to
address
some
of
the
issues
associated
with
the
implementation
of
this
rule.
For
this
reason,
EPA
has
revised
its
rationale
for
not
revising
the
NPDWR
for
lead
and
placed
it
in
the
data
gaps
category.
Although
the
Agency
continues
to
believe
that
the
NPDWR
for
copper
belongs
in
the
risk
assessment
in
process
category
at
the
present
time,
EPA
will
also
consider
copper­
related
risk
management
and
implementation
issues
as
a
part
of
any
LCR­
related
research
plans.
The
Agency
is
committed
to
working
with
stakeholders
to
support
and
coordinate
identification
and
prioritization
of
LCRrelated
research
needs.
Until
this
research
is
completed,
EPA
believes
it
is
premature
to
consider
revisions
to
the
LCR;
as
a
result,
revision
of
the
LCR
is
not
appropriate
at
this
time.
The
Agency
believes
that
understanding
the
possible
correlation
between
monitoring
results
and
actual
rates
of
exposure
and
public
health
protection
is
a
valid
issue.
However,
EPA
recognized
during
the
initial
regulatory
development
of
the
LCR
that
a
significant
effort
would
be
necessary
to
provide
a
statistically
valid
number
and
frequency
of
samples
for
an
exposure
assessment.
The
Agency
thus
adopted
an
alternative
approach
which
specified
a
monitoring
scheme
that
sought
to
``*
*
*
assure
that
systems
are
performing
`
optimal
corrosion
control'
in
part
by
requiring
systems
to
conduct
comprehensive
tap
sampling
at
homes
specifically
targeted
for
their
potential
to
contain
elevated
levels
of
lead
and
copper''
(
56
FR
26460
at
26514,
June
7,
1991
(
USEPA,
1991b)).
One
issue
in
assessing
exposure
reduction
resulting
from
the
LCR
is
a
determination
of
an
exposure
baseline.
EPA
does
not
have
a
lot
of
data
against
which
to
measure
changes
in
exposure
that
have
occurred
as
a
result
of
rule
implementation.
For
these
reasons,
EPA
believes
that
there
is
still
insufficient
information
to
change
the
basic
monitoring
approach
adopted
in
the
original
rule,
but
recognizes
that
additional
research
may
be
useful.
Research
on
whether
a
correlation
exists
between
the
water
quality
at
indoor
taps
and
water
quality
at
outdoor
taps
is
a
very
complex
issue.
Several
variables
potentially
affect
whether
a
reliable
correlation
exists
between
indoor
and
outdoor
taps.
These
variables
include:
standing
time
within
the
system;
contact
time
with
the
building
plumbing;
and
the
content
of
the
interior
plumbing.
These
variables,
coupled
with
the
fact
that
lead
levels
from
building­
to­
building
can
be
highly
site­
specific,
make
a
correlation
between
indoor
and
outdoor
taps
difficult
to
establish.
EPA
continues
to
believe
that
focusing
on
the
point
of
delivery
to
the
customer
most
closely
links
the
data
collected
to
the
water
quality
consumed
by
the
customer.
EPA
recognizes
the
commenter's
concerns
regarding
the
integrity
of
samples
collected
by
drinking
water
customers.
To
date,
however,
the
Agency
has
not
been
able
to
identify
an
acceptable
alternative
to
monitoring
at
the
consumer's
tap
that
can
produce
results
equivalent
to
those
obtained
at
the
point
of
consumption
in
terms
of
ensuring
adequate
public
health
protection.
Regarding
the
commenter's
third
recommendation,
EPA
will
consider
this
research
need
as
part
of
the
Agency's
overall
drinking
water
research
planning
process.
b.
Relaxing
the
Monitoring
Requirements.
Three
commenters
recommended
that
water
systems
be
allowed
to
conduct
water
quality
parameter
(
WQP)
monitoring
in
lieu
of
continued
lead
and
copper
tap
monitoring.
One
of
these
commenters
added
that
this
should
be
allowed
once
the
system
has
demonstrated
that
it
does
not
have
a
lead
problem.
This
commenter
also
stated
that
the
new
requirements
to
use
lead­
free
solder
and
plumbing
fixtures
should
preclude
problems
with
lead.
Two
commenters
noted
the
difficulty
that
water
systems
are
having
maintaining
their
current
sampling
pool
because
homeowners
no
longer
want
to
participate
in
the
LCR
monitoring
program.
One
of
these
commenters
recommended
using
WQP
results
to
ensure
corrosion
control
treatment
is
being
adequately
maintained
and
to
stop
lead
and
copper
monitoring
after
three
to
five
years.
The
commenter
added
that
once
the
system
ceases
lead
and
copper
monitoring,
it
can
use
public
education
to
supplement
continuing
corrosion
control,
and
can
use
coupons
to
demonstrate
that
corrosion
rates
meet
accepted
standards.
EPA
Response:
While
EPA
is
sensitive
to
the
difficulties
associated
with
the
monitoring
requirements
of
the
LCR,
the
Agency
is
also
concerned
about
the
implications
of
reduced
or
discontinued
monitoring.
Significant
treatment
changes
or
water
chemistry
disturbances
(
such
as
new
water
sources,
major
pH/
coagulation
changes,
disinfectant
changes,
or
seasonal
water/
treatment
changes)
can
influence
the
effectiveness
of
corrosion
control,
which
in
turn
will
require
appropriate
adjustments
of
treatment.
Current
regulations
require
water
systems
to
continue
monitoring
lead
and
copper
levels
to
assure
that
water
quality
changes
adversely
affecting
the
presence
of
these
contaminants
in
the
drinking
water
are
detected
and
to
assure
that
appropriate
adjustments
to
maintain
optimal
corrosion
control
are
made.
Proper
process
control,
including
water
quality
and
corrosion
inhibitor
residual
concentration
monitoring
in
the
distribution
system,
is
the
key
to
making
any
corrosion
control
or
other
treatment
work,
and
assure
the
continuation
of
proper
water
quality.
However,
EPA
recognizes
that
some
changes
might
be
justified
in
the
future
based
on
new,
scientifically
valid,
information
and/
or
research.
EPA
is
considering
aspects
such
as
the
implications
of
simultaneous
treatment
modifications
on
water
quality,
including
lead
and
copper
control,
in
its
research
planning.
EPA
is
not
yet
able
to
determine
whether
the
outcome
of
such
research
will
provide
a
basis
for
modifications
to
the
LCR
treatment
or
monitoring
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Notices
7
Treatment
changes
are
categorized
as
changes
to
any
water
quality
treatment
process,
including
(
but
not
restricted
to)
disenfection,
disinfection
byproduct
removal,
and
corrosion
control.
requirements.
As
stated
in
the
response
in
section
IV.
B.
13.
a.
of
today's
action,
EPA
has
placed
the
LCR
in
the
data
gaps
category
pending
the
completion
of
future
research.
c.
Corrosion
Control
Treatment
Strategy.
Two
commenters
noted
concerns
regarding
the
lead
and
copper
corrosion
control
strategy.
One
commenter
indicated
that
the
LCR
should
be
revised
to
allow
systems
to
change
corrosion
control
strategies.
The
commenter
stated
that
considerable
development
of
the
corrosion
control
market
has
occurred
since
systems
made
their
initial
assessments
and
implemented
corrosion
control
programs.
The
commenter
felt
that
currently,
the
``
LCR
locks
utilities
into
a
given
control
strategy,''
when
in
some
instances
limited
pilot
work
and
ongoing
WQP
monitoring
would
allow
a
system
to
re­
assesses
its
treatment
and
implement
an
alternative
corrosion
control
inhibitor.
The
second
commenter
indicated
that
the
current
corrosion
control
strategies
are
marginally
effective
at
preventing
particulate
lead
and
copper
from
entering
the
water
supply.
The
commenter
recommended
that
EPA
consider
methods
for
mitigating
the
release
of
insoluble
components
from
plumbing
fixtures.
EPA
Response:
The
Agency
disagrees
that
the
LCR
locks
utilities
into
a
given
control
strategy,
but
feels
it
is
necessary
to
demonstrate
a
sound
basis
for
reassessing
and
implementing
an
alternative
treatment
strategy
in
the
context
of
the
existing
regulation.
EPA
notes
that
the
current
regulation
provides
some
flexibility
to
both
States
and
water
systems
in
the
choice
of
a
corrosion
control
strategy.
For
example,
in
response
to
its
own
initiative,
a
request
by
a
water
system
or
other
interested
party,
a
State
may
modify
its
determination
of
the
optimal
corrosion
control
treatment,
among
those
listed
in
the
Federal
regulation,
or
may
modify
optimal
WQPs
if
the
State
determines
such
changes
are
necessary
to
ensure
that
the
system
continues
to
optimize
corrosion
control
treatment
(
40
CFR
141.82(
h)).
The
Agency
believes
that
the
existing
requirements
to
notify
the
State
when
changing
a
corrosion
control
strategy
remain
necessary
and
appropriate.
After
they
have
optimized
corrosion
control,
water
systems
must
notify
the
State
of
any
treatment
changes
7
within
60
days
of
the
change
(
40
CFR
141.90(
a)(
3)).
The
Agency
encourages
water
systems
to
notify
the
State
prior
to
making
any
changes
thus
allowing
the
Primacy
Agency
to
review
the
changes
to
reduce
the
potential
for
detrimental
sideeffects
In
the
Agency's
experience,
changes
in
treatment,
such
as
(
but
not
restricted
to)
replacement
of
high
pH
treatment
with
corrosion
inhibitor,
changes
in
coagulant
and
coagulation
conditions,
changes
in
disinfection,
installation
of
membrane
processes,
or
introduction
of
chemically
different
waters
into
the
distribution
system
provide
potential
for
detrimental
sideeffects
Water
treatment
changes,
therefore,
should
only
be
done
with
the
greatest
care
and
pilot
investigations.
While
changes
to
treatment
can
be
made
under
the
existing
regulation,
systems
should
conduct
additional
monitoring
(
e.
g.,
of
lead,
copper,
and
WQPs)
until
the
new
treatment
is
fully
implemented
and
stabilized.
EPA
also
recognizes
that
the
current
LCR
may
limit
flexibility
to
some
extent,
particularly
in
the
adoption
of
new
or
emerging
technologies.
The
original
rule
attempted
to
balance
this
concern
with
the
need
to
provide
strong
public
health
protection
by
ensuring
that
only
control
strategies
of
proven
effectiveness
are
adopted.
The
Agency
does
not
have
an
adequate
basis
to
revise
the
treatment
requirements
at
this
time
but
will
continue
to
monitor
new
developments,
including
emerging
technology.
The
Agency
may
consider
revisions
to
the
LCR
prior
to
the
end
of
the
next
Six­
Year
Review
cycle
if
the
Agency
receives
new,
scientifically­
valid,
information
that
provides
a
basis
for
achieving
significant
improvement
in
public
health
protection
or
significant
cost­
savings
to
utilities
and
their
customers
while
maintaining
current
public
health
protection.
EPA
has
always
recognized
that
the
release
of
insoluble
particulate
material
containing
lead
and
copper
can
be
an
issue
in
some
water
systems.
While
more
research
may
be
of
interest
to
improve
optimization
of
corrosion
control
approaches
with
respect
to
this
source,
EPA
expects
that
evaluations
and
pilot
studies
by
water
systems
should
include
testing
and
consideration
of
the
relative
effectiveness
of
different
treatments
towards
particulate
release
in
systems
for
which
it
is
important.
d.
Lead
Levels
in
School
Drinking
Water.
One
commenter
was
concerned
that
the
data
on
lead
levels
that
was
analyzed
under
the
Six­
Year
Review
of
NPDWR
standards
may
not
indicate
actual
lead
contamination
of
drinking
water
sources.
As
an
example,
the
commenter
noted
that
even
though
Baltimore
City
is
in
compliance
for
lead
levels,
1 
3
of
Baltimore
schools
are
using
alternative
sources
of
drinking
water
due
to
lead
contamination.
The
commenter
expressed
concern
that
since
data
obtained
from
schools,
such
as
the
data
from
Baltimore,
was
not
considered
in
the
evaluation
of
lead
contamination
in
drinking
water,
the
most
vulnerable
population
may
not
be
protected
from
exposure
to
lead.
The
commenter
stated
that
it
is
time
for
the
Agency
to
reassess
how
lead
levels
are
evaluated.
EPA
Response:
The
LCR
is
designed
to
address
system­
wide
problems
with
lead
and
copper
contamination.
The
rule
does
not
specifically
target
particular
structures,
such
as
schools,
but
rather
contains
a
monitoring
protocol
designed
to
ensure
that
the
overall
levels
of
lead
and
copper
system­
wide
are
minimized.
Once
optimal
treatment
is
implemented,
any
remaining
problems
with
elevated
lead
levels
in
schools
may
be
due
to
plumbing,
coolers,
or
other
materials
in
the
building.
These
potential
sources
of
lead
in
schools
are
of
concern
and
for
this
reason
are
explicitly
addressed
under
the
provisions
of
the
Lead
Contamination
Control
Act
of
1988
(
LCCA)
(
sections
1461
to
1465
of
SDWA).
The
LCCA
directed
EPA
to
publish
a
guidance
manual
and
testing
protocol
to
assist
States
and
schools
in
identifying
sources
and
determining
the
extent
of
lead
contamination
in
school
drinking
water
and,
if
necessary,
in
remedying
such
contamination.
In
January
1989,
the
Agency
published
and
distributed
the
guidance
manual,
``
Lead
in
School's
Drinking
Water,''
to
States
and
schools
(
USEPA,
1989).
In
1994,
the
Agency
updated
and
revised
the
guidance
manual
entitled
``
Lead
in
Drinking
Water
in
Schools
and
Nonresidential
Buildings''
(
USEPA,
1994).
A
copy
of
this
manual
may
be
obtained
from
the
Safewater
website
http://
www.
epa.
gov/
safewater/
consumer/
leadinschools.
html.
In
addition,
the
LCCA
imposed
a
ban
on
the
manufacture
and
sale
of
water
coolers
that
are
not
lead
free.
The
LCCA
requirements
are
independent
of
the
NPDWRs
and
therefore
are
not
addressed
under
the
Six­
Year
Review
process.
However,
the
Agency
is
continuing
to
work
with
schools
and
States
to
address
problems
dealing
with
lead
in
school
drinking
water.

14.
Lindane
(
g­
hexachlorocyclohexane)
In
the
April
17,
2002,
Federal
Register,
the
Agency
preliminarily
placed
lindane
in
the
no
revision
category
because
a
health
risk
assessment
was
pending
at
the
time
of
publication.
One
commenter
stated
that
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the
RED
risk
assessment
for
lindane,
issued
after
publication
of
the
April
17,
2002,
Federal
Register,
should
be
considered
in
the
Agency's
review
of
the
NPDWR
and
expressed
concerns
regarding
the
existing
regulation.
The
commenter
stated
that
the
current
NPDWR
is
based
on
an
RfD
developed
in
1988
on
the
basis
of
adverse
kidney
effects
and
should
be
revised
(
USEPA,
1988).
The
kidney
effects
were
determined
to
occur
through
a
pathway
that
is
not
relevant
to
human
health
risk
assessment.
The
commenter
stated
that
the
new
OPP
toxicological
assessment
has
resulted
in
a
significant
change
to
the
quantitative
dose­
response
assessment
for
lindane
and
that
there
are
no
data
gaps
or
uncertainties
which
would
prevent
a
revision
of
the
NPDWR
for
lindane
at
this
time.

EPA
Response:
Since
the
publication
of
the
April
17,
2002,
Federal
Register
and
receipt
of
the
comment
regarding
lindane,
the
Agency
has
finalized
the
risk
assessment
for
lindane
and
signed
the
RED
on
July
31,
2002.
The
remaining
paragraphs
in
this
section
include
a
brief
background
discussion
about
the
original
promulgation
of
the
lindane
NPDWR,
the
results
of
the
appropriate
six­
year
technical
reviews
and
the
Agency's
revise/
not
revise
decision.
a.
Background.
EPA
published
the
current
NPDWR
for
lindane
on
January
30,
1991
(
56
FR
3526
(
USEPA,
1991a)).
The
NPDWR
established
an
MCLG
and
an
MCL
of
0.0002
mg/
L.
The
Agency
based
the
MCLG
on
an
RfD
of
0.0003
mg/
kg/
day
and
a
cancer
classification
of
C,
possible
human
carcinogen.
b.
Technical
Reviews.
EPA
updated
the
risk
assessment
on
July
31,
2002
(
USEPA,
2002h).
The
new
risk
assessment
established
an
RfD
of
0.0047
mg/
kg/
day.
The
Food
Quality
Protection
Act
(
FQPA)
of
1996
provides
for
an
additional
safety
factor
of
up
to
10­
fold,
if
necessary,
in
assessing
the
risks
to
infants
and
children
to
take
into
account
the
potential
for
pre­
and
post­
natal
toxicity,
and
the
completeness
of
the
toxicity
and
exposure
databases.
This
is
referred
to
as
the
FQPA
safety
factor.
The
Agency
concluded
that
an
FQPA
safety
factor
of
three
was
required
for
lindane
since
there
is
evidence
for
increased
susceptibility
of
the
young
demonstrated
in
a
developmental
neurotoxicity
and
two­
generation
reproductive
toxicity
study
in
rats.
The
rationale
for
using
an
FQPA
safety
factor
of
three
is
detailed
in
the
RED.
In
accordance
with
the
1999
EPA
Draft
``
Guidelines
for
Carcinogen
Risk
Assessment''
(
USEPA,
1999a),
the
Agency
classified
lindane
as
``
suggestive
evidence
of
carcinogenicity,
but
not
sufficient
to
assess
human
carcinogenic
potential.''
Based
on
the
RfD
for
lindane
of
0.0047
mg/
kg/
day,
the
application
of
the
additional
FQPA
safety
factor
of
three
to
this
RfD,
a
20
percent
RSC,
and
a
10­
fold
risk
management
factor
of
suggested
evidence
of
carcinogenicity,
EPA
used
0.001
mg/
L
as
a
level
for
evaluating
the
occurrence
data.

Analytical
or
treatment
feasibility
do
not
pose
any
limitations
for
the
current
MCL
and
would
not
be
a
limiting
factor
at
the
0.001
mg/
L
level
(
USEPA,
2003a;
USEPA
2003g).
The
Agency's
review
of
possible
``
other
regulatory
revisions''
did
not
identify
any
issues
that
are
specific
to
lindane
(
USEPA,
2003b).

EPA
evaluated
the
results
of
the
occurrence
and
exposure
analyses
for
lindane
to
determine
whether
possible
changes
to
the
standard
would
be
likely
to
result
in
a
meaningful
opportunity
for
cost­
savings
to
public
water
systems
and
their
customers
(
USEPA,
2003d).
Table
IV
 
2
shows
the
results
of
the
detailed
occurrence
and
exposure
analysis
based
on
the
16­
State
cross­
section
for
concentrations
of
0.0002
mg/
L
(
the
current
MCL),
and
for
0.001
mg/
L.
Based
on
the
detailed
analysis,
it
appears
that
lindane
is
unlikely
to
occur
at
concentrations
above
0.0002
mg/
L
in
the
States
used
for
the
cross­
section.

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The
results
of
the
detailed
occurrence
and
exposure
analysis
indicate
that
few,
if
any,
of
the
16,098
systems
sampled
in
the
16­
State
cross­
section
might
be
affected
if
EPA
were
to
consider
levels
as
high
as
0.001
mg/
L.
The
current
BATs
and
small
system
compliance
technology
for
lindane
have
other
beneficial
effects
(
e.
g.,
reduction
of
other
co­
occurring
contaminants,
or
other
common
impurities)
in
addition
to
lindane
removal.
Therefore,
if
EPA
were
to
consider
a
higher
level,
the
Agency
does
not
know
how
many
of
these
public
water
systems
that
are
currently
treating
to
comply
with
the
current
MCL
of
0.0002
mg/
L
would
be
likely
to
discontinue
any
treatment
that
is
already
in
place
(
USEPA,
2002c;
USEPA,
2003g).
c.
Current
Decision.
Although
there
are
new
health
effects
data
that
might
support
calculation
of
a
less
stringent
standard
for
lindane,
EPA
does
not
believe
a
revision
to
the
NPDWR
for
lindane
is
appropriate
at
this
time.
In
making
this
decision,
the
Agency
considered
whether
any
potential
revision
to
the
lindane
NPDWR
is
likely
to
provide
a
meaningful
opportunity
for
cost­
savings
to
public
water
systems
and
their
customers.
After
consideration
of
this
factor,
EPA
has
decided
that
any
revision
to
lindane
would
be
a
low
priority
activity
for
the
Agency,
and,
thus,
is
not
appropriate
to
revise
at
this
time
because
of:
 
Competing
workload
priorities;
 
The
administrative
costs
associated
with
rulemaking;
and
 
The
burden
on
States
and
the
regulated
community
to
implement
any
regulatory
change
that
resulted.

15.
Simazine
One
commenter
agreed
that
simazine
should
be
addressed
after
the
risk
assessment
is
completed
in
2003
or
2004.
The
commenter
requested
that
the
Office
of
Water
(
OW)
work
closely
with
the
OPP
on
the
risk
assessment
at
that
time.
The
commenter
also
recommended
that
OW
address
the
revision
of
the
existing
simazine
NPDWR
before
the
next
review
cycle
year,
scheduled
for
2008.
The
commenter
believes
the
extensive
mammalian
toxicology
database,
submitted
as
part
of
the
Triazine
Special
Review,
can
be
used
in
this
process.
EPA
Response:
OW
has
been
coordinating
with
OPP
for
the
revision
of
the
atrazine
and
simazine
risk
assessments.
Once
the
simazine
risk
assessment
is
completed,
EPA
will
determine
whether
a
compelling
reason
exists
to
consider
review
of
the
simazine
NPDWR
on
an
accelerated
schedule.
C.
What
Comments
Did
EPA
Receive
Regarding
the
Review
of
Implementation­
Related
Issues
for
Chemical
NPDWRs?

Several
commenters
recommended
that
EPA
ensure
consistent
application
of
rules
by
making
rules
more
consistent
with
respect
to
monitoring
frequency,
triggers
for
increased
monitoring,
criteria
for
returning
to
routine
monitoring,
and
criteria
for
reducing
sample
requirements.
In
addition,
commenters
suggested
that
the
Agency
review
possible
ways
for
reducing
the
reporting
burden
on
States,
which
could
free
up
State
resources
currently
used
to
implement
rules.
One
commenter
was
concerned
about
monitoring
and
reporting
issues
in
conjunction
with
CMR.
The
commenter
felt
that
EPA
should
not
miss
an
opportunity
to
relieve
some
of
the
unnecessary
confusion
that
the
monitoring
requirements
of
Phase
II
and
V
have
created.
This
confusion
includes
issues
such
as,
what
a
detection
is
and
what
the
monitoring
requirements
are
for
systems
in
States
without
a
waiver
program.
EPA
was
encouraged
to
provide
this
consistency
as
much
as
possible,
including
using
the
standard
monitoring
framework
to
allow
States
and
water
systems
to
more
easily
understand
rule
requirements
and
reduce
the
need
for
States
to
update
their
data
management
systems.
One
commenter
said
EPA
should
ensure
consistent
application
of
rules
by
determining
whether
or
not
chronic
contaminants
should
be
regulated
at
non­
transient
non­
community
water
systems
(
NTNCWSs),
and
review
existing
NPDWRs
to
ensure
that
rules
are
applied
consistently.
Another
commenter
recommended
that
the
compliance
language
for
the
synthetic
organic
chemicals
(
SOCs)
and
volatile
organic
chemicals
(
VOCs)
in
the
Final
Arsenic
Rule
(
66
FR
6975,
January
22,
2001
(
USEPA,
2001))
be
adopted
for
the
inorganic
chemicals
(
IOCs),
and
that
systems
not
be
considered
in
violation
of
the
MCL
until
it
has
completed
one
year
of
quarterly
samples.
EPA
Response:
The
Agency
agrees
that
consistency
across
regulations
is
desirable
to
the
extent
that
it
does
not
jeopardize
public
health
protection
or
the
environment.
As
part
of
the
Advanced
Notice
of
Proposed
Rulemaking
for
CMR
(
62
FR
36100,
July
3,
1997
(
USEPA,
1997a)),
EPA
considered
some
of
the
issues
raised
by
the
commenters.
However,
during
the
comment
period
for
the
CMR,
stakeholders
generally
indicated
that
the
existing
monitoring
framework
was
sufficient.
Most
State
commenters
indicated
that
it
would
be
too
burdensome
to
adopt
CMR.
As
a
result,
the
Agency
decided
to
take
no
further
action
on
the
CMR.
However,
the
Agency
established
a
standardized
monitoring
framework
which
applies
to
all
of
the
regulated
chemical
and
radiological
contaminants
(
except
lead
and
copper).
The
new
chemical
and
radiological
rules
that
EPA
has
promulgated
(
e.
g.,
arsenic
and
radionuclides)
are
coordinated
with
the
standardized
monitoring
framework.
The
Agency
made
special
efforts
to
ensure
that
the
reduced
monitoring
periods
are
in
line
with
the
3­
year
compliance
periods
in
the
standardized
monitoring
framework.
To
assist
States
with
understanding
rule
requirements,
the
Agency
conducted
a
series
of
Phase
II/
V
training
in
2001.
The
training
provided
information
to
help
States
make
informed
decisions
about
reducing
quarterly
monitoring
requirements.
With
respect
to
reduced
monitoring,
States
currently
have
the
flexibility
to
reduce
the
frequency
of
monitoring
and/
or
to
waive
sampling
requirements
for
any
given
contaminant
after
minimum
criteria
are
met
to
demonstrate
that
the
system
is
reliably
and
consistently
below
the
MCL
and/
or
not
vulnerable
to
contamination.
NTNCWSs
are
traditionally
regulated
for
chronic
contaminants.
However,
through
an
alternative
mechanism,
the
Agency
is
currently
evaluating
risk
and
exposure
as
they
pertain
to
NTNCWS
monitoring
requirements.
This
review
will
not
be
completed
in
time
for
this
Six­
Year
Review
process.
Until
all
the
issues
have
been
identified
and
specific
options
have
been
formulated,
it
will
not
be
clear
if
a
revision
to
regulations
is
indicated.
EPA
intends
to
consistently
implement
compliance
determination
provisions
for
IOCs,
SOCs,
and
VOCs
for
all
NTNCWSs
and
community
water
systems,
as
described
in
the
preamble
to
the
Final
Arsenic
Rule
(
66
FR
6975
at
6990,
January
22,
2001
(
USEPA,
2001)).
The
rule
makes
compliance
determinations
based
on
a
running
annual
average.
The
clarifications
to
compliance
determinations
for
SOCs,
IOCs,
and
VOCs
are
based
on
the
average
of
the
initial
MCL
exceedance
and
any
subsequent
State­
required
confirmation
samples.
States
have
the
flexibility
to
require
confirmation
samples
and
more
frequent
monitoring,
in
addition
to
required
quarterly
samples.
The
average
of
the
exceedance
and
confirmation
sample
constitutes
the
first
quarterly
sample.
Compliance
with
the
MCL
is
based
on
the
average
of
the
first
quarterly
sample
and
three
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additional
samples
over
a
period
of
one
year,
unless
any
one
quarterly
sample
would
cause
the
running
annual
average
to
exceed
the
MCL.
Then
the
system
is
out
of
compliance
immediately.

D.
What
Comments
Did
EPA
Receive
on
the
Total
Coliform
Rule?
Several
commenters
addressed
the
TCR.
Several
commenters
raised
several
issues
relating
to
monitoring.
Some
contended
that
routine
monitoring
should
be
focused
on
critical
locations
in
the
distribution
system,
rather
than
on
the
current
requirement
to
monitor
all
parts
of
the
distribution
system.
They
also
urged
EPA
to
allow
the
use
of
dedicated
sampling
taps.
Some
commenters
argued
for
allowing
a
finished
water
storage
reservoir
as
a
routine
monitoring
site.
Two
commenters
urged
EPA
to
focus
on
E.
coli
as
the
measure
of
water
quality
in
the
distribution
system,
rather
than
on
total
coliforms.
In
addition
to
routine
monitoring,
a
few
commenters
addressed
the
topic
of
repeat
samples
after
a
total
coliform­
positive
sample.
One
commenter,
for
example,
urged
EPA
to
eliminate
the
requirement
to
take
upstream
and
downstream
repeat
samples
after
a
total
coliform­
positive
sample.
Environmental
groups
urged
EPA
to
strengthen
the
TCR
and
other
rules
that
protect
against
pathogens,
and
exhorted
EPA
not
to
ease
the
TCR
burden
such
that
public
health
is
compromised.
EPA
Response:
EPA's
announcement
in
the
April
17,
2002,
Federal
Register
was
only
intended
to
discuss
the
Agency's
intent
to
begin
the
process
for
revising
the
TCR.
EPA
will
consider
the
commenters'
suggestions
as
part
of
the
revision
process.
As
stated
in
the
April
17,
2002,
Federal
Register,
the
Agency
plans
to
consider
revisions
to
the
TCR
with
new
requirements
for
ensuring
the
integrity
of
distribution
systems.
The
Agency
remains
committed
to
obtaining
input
from
stakeholders
as
part
of
the
rule
development
process.
EPA
agrees
with
the
comment
that
public
health
should
not
be
compromised,
and
will
consider
only
those
revisions
that
will
assure
public
health
protection.

E.
What
Comments
Did
EPA
Receive
on
Research
Needs?
Commenters
found
that
EPA's
information
on
potential
research
resulting
from
the
review
of
NPDWRs
would
be
better
represented
by
a
summary
of
research
needs
that
were
identified
by
the
Agency.
Commenters
felt
that
this
summary
is
important
to
inform
future
regulatory
decisions.
Commenters
also
suggested
additional
research
needs
that
had
not
been
identified
by
EPA
in
its
preliminary
review.
EPA
Response:
EPA
agrees
that
the
identification
of
research
needs
is
an
important
component
of
the
review
of
NPDWRs.
Research
findings
may
support
future
reviews
and/
or
revisions
to
NPDWRs.
The
Agency
is
considering
research
needs
that
it
identified
as
part
of
the
review
as
well
as
those
suggested
by
commenters.
EPA
will
continue
to
identify
areas
where
data
are
lacking.
Dialogue
with
industry
and
other
groups,
including
those
that
sponsor
or
conduct
research
on
priority
areas,
would
be
beneficial
to
the
drinking
water
program.
Collaboration
in
sponsoring
studies
can
provide
multiple
benefits.
There
are
two
research
needs
associated
with
the
Six­
Year
Review
that
are
being
addressed
through
mechanisms
external
to
EPA.
The
National
Research
Council
of
the
National
Academy
of
Sciences
is
conducting
an
assessment
of
recent
data
on
fluoride
health
effects.
In
addition,
the
National
Toxicology
Program
is
conducting
a
study
on
chromium
VI
toxicity.
Both
of
these
research
efforts
are
discussed
in
the
April
17,
2002,
Federal
Register
announcement
of
EPA's
preliminary
revise/
not
revise
decisions.
The
current
review
identified
several
general
and
specific
areas
of
potential
research
related
to
treatment.
The
treatment­
related
research
areas
are
briefly
discussed
in
the
Treatment
Feasibility
Document
(
USEPA,
2003g).
EPA
is
currently
in
the
process
of
examining
whether
specific
research
needs
exist
within
each
of
the
Six­
Year
Review
areas
of
regulatory
consideration
(
i.
e.,
health
effects,
analytical
methods,
treatment,
implementation,
and
occurrence/
exposure).
Some
of
the
research
needs
identified
during
the
Six­
Year
Review
effort
will
be
discussed
in
the
context
of
the
Multi­
Year
Plan
(
MYP)
for
drinking
water.
The
MYP
describes
the
EPA
Office
of
Research
and
Development's
fiscal
year
2003
to
2010
research
program
to
support
the
regulatory
development
activities
of
the
EPA
Office
of
Water.
EPA
plans
to
make
this
document
available
to
the
public
in
2003.

V.
References
National
Drinking
Water
Advisory
Council
(
NDWAC).
2000.
Recommended
Guidance
for
Review
of
Existing
National
Primary
Drinking
Water
Regulations.
November
2000.
Available
on
the
Internet
at:
http://
www.
epa.
gov/
safewater/
ndwac/
guidfnl.
pdf.
National
Research
Council
(
NRC).
1993.
Health
Effects
of
Ingested
Fluoride.
National
Academy
Press,
Washington,
DC.
August
1993.
Available
on
the
Internet
at:
http://
books.
nap.
edu/
books/
030904975X/
html/
R1.
html.
National
Toxicology
Program
(
NTP).
2002.
NTP
study
of
the
hexavalent
chromium
compound
sodium
dichromate
dihydrate.
Available
on
the
Internet
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Dated:
July
11,
2003.
Linda
J.
Fisher,
Acting
Administrator.
[
FR
Doc.
03
 
18152
Filed
7
 
17
 
03;
8:
45
am]

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