Safe
Drinking
Water
Act
Contaminant
Candidate
List
(
3/
1998)

Purpose:
:
The
1996
amendments
to
the
Safe
Drinking
Water
Act
require
the
EPA
to
publish
a
list
of
contaminants
that
are
known
or
anticipated
to
be
present
in
public
water
systems.

The
list
must
be
published
after
consultation
with
the
scientific
community,
including
the
Science
Advisory
Board,
after
notice
and
opportunity
for
public
comment,
and
after
consideration
of
the
occurrence
database
established
under
section
1445(
g).
The
unregulated
contaminants
considered
for
the
list
must
include,
but
not
be
limited
to,
substances
referred
to
in
section
101(
14)
of
the
Comprehensive
Environmental
Response,
Compensation,
and
Liability
Act
of
1980
(
CERCLA),
and
substances
registered
under
the
Federal
Insecticide,
Fungicide,
and
Rodenticide
Act
(
FIFRA).
During
the
development
of
the
CCL,
the
Agency
consulted
with
stakeholders,
including
the
National
Drinking
Water
Advisory
Council's
(
NDWAC)
Working
Group
on
Occurrence
&
Contaminant
Selection,
which
includes
microbiologists,
toxicologists,
public
health
scientists,
and
engineers,
and
consulted
with
other
members
of
the
scientific
community
including
the
Science
Advisory
Board
(
SAB).

The
initial
list
was
published
in
march
1998.
To
meet
the
required
revision
schedule
the
next
list
is
due
in
2003.

Chemicals:
The
draft
list
included
263
chemicals
from
8
source
lists.
The
final
list
was
reduced
to
50
chemical
and
10
microbial
contaminants.

Sample
Locations:
None.
This
is
a
compilation
of
results
from
many
sources.

Sample
Design:
None.
This
list
is
a
summary
of
data
from
several
lists
of
possible
contaminants
including
the
Drinking
Water
Priority
List,
Health
Advisories,
IRIS,
PWS,
CERCLA,
Stakeholder
summary
list,
TRI,
and
OPP
ranking.

The
initial
list
of
contaminants
considered,
as
well
as
those
eliminated
or
deferred
from
consideration,
are
in
Table
3
(
attached).
The
following
sections
provide
a
description
of
each
of
the
lists
and
the
rationale
behind
including
it
with,
or
excluding
it
from,
the
initial
list
of
contaminants
considered.

a.
1991
Drinking
Water
Priority
List.
The
SDWA,
as
amended
in
1986,
required
EPA
to
publish
a
triennial
list
of
priority
contaminants,
the
DWPL,
which
may
require
regulation.
The
first
list
containing
53
contaminants/
contaminant
group
was
published
on
January
2,
1988
(
53
FR
1892).
Since
none
of
the
contaminants
had
been
selected
for
regulation,
EPA
revised
and
updated
the
1988
list
three
years
later.
The
revised
and
updated
list,
published
on
January
14,
1991
(
56
FR
1470),
contained
50
substances
carried
over
from
the
1988
list
and
27
new
substances,
bringing
the
total
number
of
contaminants/
contaminant
groups
to
77,
including
one
microorganism.
In
consideration
of
the
statutory
requirements
and
the
time
frame
for
rulemaking
in
the
SDWA
at
the
time,
EPA
used
the
following
criteria
to
select
contaminants
for
the
DWPL:
(
1)
occurrence
or
the
potential
occurrence
of
the
substance
in
public
water
systems;
(
2)
documented
or
suspected
adverse
health
effects;
and
(
3)
the
availability
of
sufficient
information
on
the
substance
so
that
a
regulation
could
be
developed
within
the
statutory
time
frame.
The
contaminants
were
selected
from
the
following
groups:
disinfectants
and
their
byproducts,
the
first
group
of
100
contaminants
on
the
1987
CERCLA
priority
list
of
hazardous
substances
(
52
FR
12866),
design
analytes
of
the
EPA
National
Pesticide
Survey
conducted
between
1987­
1990,
pesticides
with
high
potential
for
leaching
in
groundwater,
substances
recommended
by
the
States
and
EPA
regions,
unregulated
contaminants
monitored
under
Section
1445
of
the
SDWA,
and
certain
substances
reported
frequently
and
at
high
concentrations
in
drinking
water.
The
selection
of
contaminants
was
made
with
the
assistance
of
the
DWPL
workgroup
which
consisted
of
representatives
from
various
programs
within
the
Agency,
the
National
Toxicology
Program,
the
U.
S.
Geological
Survey,
and
the
Agency
for
Toxic
Substances
and
Disease
Registry.
For
development
of
the
draft
CCL,
the
Agency
selected
contaminants
from
the
1991
DWPL
that
were
not
specifically
addressed
by
other
regulations
under
development.
Thus,
all
contaminants
specifically
addressed
by
the
disinfectants
and
disinfection
byproducts
regulation
were
eliminated
from
consideration.

b.
Health
advisories.
The
Health
Advisories
(
HAs)
are
prepared
for
contaminants
that
have
the
potential
to
cause
adverse
human
health
effects
and
which
are
known
or
anticipated
to
occur
in
drinking
water,
but
for
which
no
national
regulations
currently
exist.
Each
HA
contains
information
on
the
nature
of
the
adverse
health
effects
of
the
contaminant
and
the
concentrations
that
would
not
be
anticipated
to
cause
an
adverse
effect
following
various
periods
of
exposure.
HAs
also
summarize
available
data
on
occurrence,
pharmacokinetics,
environmental
fate,
health
effects,
available
analytical
methods,
and
treatment
techniques
for
the
contaminant.
HA
concentration
levels
include
a
margin
of
safety
to
protect
sensitive
members
of
the
population
(
e.
g.,
children,
the
elderly,
pregnant
women).
The
Office
of
Water
Health
Advisory
Program
was
initiated
to
provide
information
and
guidance
to
individuals
and
agencies
concerned
with
potential
risk
from
drinking
water
contaminants.
HAs
are
used
only
for
guidance
and
are
not
legally
enforceable,
and
are
subject
to
change
as
new
information
becomes
available.
For
purposes
of
developing
the
draft
CCL,
all
contaminants
with
HAs,
or
HAs
under
development,
were
considered.

c.
Integrated
Risk
Information
System.
The
Integrated
Risk
Information
System
(
IRIS)
is
an
EPA
on­
line
database
containing
health
risk
and
EPA
regulatory
information.
IRIS
lists
chemicals
of
interest
or
concern
for
which
the
Agency
has
reached
consensus
regarding
adverse
health
effects.
When
available,
a
reference
dose
(
RfD)
for
non­
cancer
health
effect
resulting
from
oral
exposure
is
reported
with
information
about
how
the
RfD
was
derived
and
any
uncertainty
regarding
the
source
studies.
An
RfD
is
an
estimate
of
a
daily
exposure
to
the
human
population
that
is
likely
to
be
without
appreciable
risk
of
adverse
effect
over
a
lifetime
of
exposure.
For
carcinogens,
a
carcinogenic
assessment,
or
cancer
potency
factor,
is
reported
for
both
oral
and
inhalation
exposure.
The
cancer
potency
factor
is
the
estimated
risk
to
the
human
population
of
cancer
effects
over
a
lifetime
of
exposure.
In
1992,
in
anticipation
of
the
next
DWPL,
the
Agency
developed
a
list
of
chemicals
based
on
a
risk­
based
screen
of
chemicals
in
IRIS.
There
were
approximately
600
chemicals
in
the
IRIS
database
in
1992,
and
312
were
selected
for
further
screening.
The
312
were
chosen
because
they
had
defined
toxicity
via
the
oral
route
of
exposure
and
did
not
have
NPDWRs.
The
312
chemicals
were
screened
using
the
following
categories:
(
1)
using
Storage
and
Retrieval
(
STORET)
data,
chemicals
were
identified
with
concentration
in
water
that
exceeded
the
drinking
water
equivalent
level
(
DWEL)
which
was
derived
from
the
reference
dose
or
cancer
potency;
(
2)
chemicals
were
identified
that
were
produced
in
quantities
exceeding
one
billion
pounds
per
year;
(
3)
pesticides
were
identified
with
use
exceeding
1000
tons
per
year;
and
(
4)
chemicals
were
identified
that
were
reported
in
the
Toxic
Release
Inventory
(
TRI)
database
as
discharged
to
surface
water
in
excess
of
100
tons
per
year.
Sixteen
chemicals
met
the
STORET
criteria;
nine,
the
production
criteria;
31,
the
pesticides
criteria;
and
6,
the
TRI
criteria.
A
total
of
48
individual
chemicals
were
identified,
and
some
were
identified
by
more
than
one
screen.
All
48
contaminants
were
included
on
the
initial
list
for
consideration.

d.
Non­
Target
Analytes
in
Public
Water
Supply
Samples.
In
anticipation
of
the
1994
DWPL,
the
Agency
consulted
with
analytical
laboratories
that
routinely
analyze
samples
for
public
water
systems
to
determine
what
contaminants
were
occurring
that
were
not
currently
regulated.
A
list
of
contaminants
tentatively
identified
in
1991
from
drinking
water
samples
collected
for
compliance
monitoring
was
developed.
These
contaminants,
also
referred
to
as
non­
targets
analytes,
are
compounds
identified
by
the
spikes
found
on
the
chromatograph.
The
concentrations
for
these
compounds
were
not
measured.
These
non­
target
analytes
represent
the
monitoring
experience
of
several
water
systems
with
operations
in
various
states.
The
contaminants
included
on
the
initial
list
for
consideration
are
a
subset
of
23
contaminants
chosen
from
the
larger
list
of
non­
targets
analytes.
The
23
contaminants
were
chosen
because
they
were
considered
to
be
related
to
possible
anthropogenic
sources.

e.
CERCLA
Priority
List.
In
developing
the
CCL,
the
SDWA
requires
EPA
to
consider
substances
referred
to
in
section
101(
14)
of
the
CERCLA.
CERCLA
requires
the
Agency
for
Toxic
Substances
and
Disease
Registry
(
ATSDR)
to
prepare
a
list
in
the
order
of
priority
of
hazardous
substances
which
are
most
commonly
found
at
facilities
on
the
CERCLA
National
Priority
List
(
NPL).
In
1995,
ATSDR
developed
a
list
of
275
hazardous
substances
ranked
by
the
order
of
priority.
(
ATSDR,
1996)
To
develop
this
list,
ATSDR
considered
750
of
2800
substances
present
at
NPL
sites
and
ranked
them
based
on
the
following
three
criteria,
which
were
combined
to
result
in
a
total
score.
These
criteria
were:
(
1)
Frequency
of
occurrence
at
NPL
sites,
(
2)
toxicity,
and
(
3)
potential
for
human
exposure.
The
number
of
NPL
sites
at
which
a
substance
was
identified
in
any
medium
was
used
to
indicate
the
frequency
of
occurrence.
EPA's
Reportable
Quantity
(
RQ)
was
used
to
assess
the
toxicity
of
candidate
substance.
If
a
RQ
was
not
available,
the
RQ
methodology
was
applied
to
candidate
substances
to
establish
a
Toxicity/
Environmental
Score.
The
human
exposure
component
was
based
on
two
parts:
the
concentration
of
the
substance
in
the
environmental
media
and
the
exposure
status
of
population.
EPA
included
the
top
50
substances
from
the
1995
CERCLA
prioritized
list
of
275
substances
for
consideration
for
the
draft
CCL.

f.
Stakeholder
responses.
In
December
1996,
the
EPA
convened
its
first
stakeholder
meeting
on
the
contaminant
identification
process.
At
that
meeting,
EPA
requested
input
on
what
contaminants
to
include
on
its
first
CCL.
At
the
December
meeting,
and
following,
participants
have
provided
input
to
the
Agency
on
contaminants
for
inclusion
on,
or
exclusion
from,
the
CCL.
Some
stakeholders
provided
information
on
health
effects
or
occurrence,
or
both,
while
others
listed
contaminants.
All
contaminants
suggested
by
stakeholders
were
included
for
initial
consideration
except
those
which
already
had
NPDWRs,
or
which
were
included
under
other
regulatory
activity
mentioned
in
section
VIII
of
this
notice.

g.
Toxic
Release
Inventory.
Another
source
of
available
information
which
could
serve
as
a
predictor
of
anticipated
occurrence
in
drinking
water,
is
the
TRI.
This
data
base,
established
under
the
Emergency
Planning
and
Community
Right­
to­
Know
Act
of
1986,
contains
information
from
manufacturing
facilities
in
the
United
States
regarding
transfers
and
releases
of
toxic
and
hazardous
materials
to
air,
ground
and
water.
The
most
recent
report
analyzed
data
gathered
for
calendar
year
1994
from
22
chemical
categories
and
included
343
separate
chemicals
from
23,000
facilities
which
met
certain
thresholds
requiring
submission
of
data.
(
U.
S.
EPA,
1997c).
In
order
to
assess
the
potential
for
a
chemical
to
be
a
contaminant
in
public
water
systems,
EPA
conducted
an
analysis
of
the
release
and
emissions
data.
Each
of
the
four
categories
of
emissions
or
discharges
were
assigned
a
threshold
value
above
which
the
contaminant
was
deemed
to
fit
within
the
criteria
of
the
SDWA,
as
a
contaminant
anticipated
to
occur
in
public
water
systems.
The
threshold
did
not
attempt
to
attribute
differences
in
reactivity,
solubility,
mobility
or
toxicity
of
the
pollutants
at
this
stage
of
the
contaminant
evaluation
process,
but
involved
simply
determining
a
gross
anticipation
factor.
If
a
contaminant
was
released
via
an
on­
site
discharge
to
the
environment,
EPA
judged
that
it
was
reasonable
to
anticipate
it
as
a
contaminant
in
public
water
systems
to
varying
degrees,
depending
upon
the
media
receiving
the
discharge.
The
overall
analysis
of
the
above
TRI
criteria
resulted
in
58
chemicals
from
the
various
discharges
meeting
the
criteria.
Where
a
release
was
close
to
the
threshold,
it
was
included
in
the
tally.
Several
chemicals
met
the
criteria
but
were
excluded
because
there
is
an
existing
standard
(
e.
g.,
hydrofluoric
acid­­
fluoride
is
regulated)
or
a
standard
under
consideration
(
sulfuric
acid­­
there
is
regulatory
activity
currently
underway
regarding
sulfate).
Other
contaminants
such
as
ammonia,
hydrochloric
acid,
or
methanol
were
not
believed
to
represent
a
significant
threat
to
drinking
water
due
to
limited
persistence,
leaving
51
contaminants.
Of
the
51
contaminants,
49
met
the
criteria
for
air
release,
21
from
stack
emissions,
38
for
fugitive
emissions,
11
via
underground
injection,
13
from
land
release,
and
30
for
surface
water
releases.
All
51
were
included
for
initial
consideration
in
Table
3.

h.
Pesticides
identified
by
Office
of
Pesticide
Programs.
In
developing
the
CCL,
the
SDWA
requires
EPA
the
consider
substances
referred
to
in
the
FIFRA.
During
the
development
of
the
draft
CCL,
the
Agency's
Office
of
Ground
Water
and
Drinking
Water
sought
assistance
from
the
Office
of
Pesticide
Programs
(
OPP)
in
determining
what
pesticides
should
be
priorities
for
the
drinking
water
program.
In
response
to
the
request,
OPP
provided
recommendations
for
a
number
of
pesticides.
(
U.
S.
EPA,
1997b)
The
list
of
pesticides,
based
on
physical­
chemical
properties,
occurrence
and
extent
of
use,
was
ranked
using
the
Ground
Water
(
GW)
Risk
score,
a
calculated
potential
to
leach
to
ground
water.
Pesticides
with
a
GW
Risk
of
2.0
or
greater
were
included
for
initial
consideration
in
developing
the
CCL
(
see
Table
3).
However,
later
during
the
data
evaluation
and
screening
phase
of
the
draft
CCL
development,
the
decision
was
made
to
defer
some
of
the
pesticides
identified
by
the
OPP
GW
Risk
of
2.0
or
greater.
The
pesticides
in
Table
4
include
those
where
the
GW
Risk
value
of
2.0
or
greater
was
the
only
factor
for
inclusion
on
the
CCL.
The
decision
was
made,
that
for
these
cases,
inclusion
on
the
CCL
would
be
deferred
pending
further
evaluation
of
the
potential
of
these
pesticides
to
occur
at
levels
of
health
concern.
Many
new
pesticides
for
which
no
other
data
exists
are
included
in
Table
4.
Table
4.
Pesticides
Deferred
Asulam
bensulfuron
methyl
bentazon
bromacil
Cadre
chlorimuron
ethyl
chlorsulfuron
Diazinon­­
oxypyrimidine
Dicamba
Ethylenethiourea
(
ETU)
Fenamiphos
Fluometuron
Halofenozide
Halosulfuron
Hexazinone
Imazamethabenz
Imazapyr
Imazaquin
Imazethapyr
MCPA
(
Methoxone)
Methsulfuron
methyl
Nicosulfuron
Norflurazon
Primisulfuron
methyl
Prometryn
Propazine
Prosulfuron
Pyrithiobac­
Na
Rimsulfuron
Sulfentrazone
Sulfometuron
methyl
Tebufenozide
Terbufos
sulfone
Thiazopyr
Triasulfuron
The
Agency
is
working
to
develop
a
tool
to
estimate
concentrations
in
ground
and
surface
waters
based
on
physical­
chemical
properties
and
pesticide
use
volumes,
and
then
compare
the
estimated
concentrations
with
health
advisory
levels
or
calculated
health
levels
based
on
reference
doses
or
cancer
potency.
The
model
is
expected
to
be
completed
and
available
for
use
at
the
end
of
1997,
and
at
that
time
the
Agency
will
reevaluate
the
inclusion
for
the
additional
pesticides
on
Table
4
on
the
CCL.
On
August
4,
1997,
EPA
announced
its
schedule
for
reassessing
tolerances
for
pesticide
residues
on
raw
and
processed
foods
(
62
FR
42020).
Publication
of
this
schedule
was
pursuant
to
the
requirements,
as
established
by
the
Food
Quality
Protection
Act
of
1996
(
FQPA).
Under
this
new
law,
EPA
is
required
to
reassess
all
existing
tolerances
and
exemptions
from
tolerances
for
both
active
and
inert
ingredients.
EPA
is
directed
to
give
priority
review
to
pesticides
that
appear
to
present
risk
concerns
based
on
current
data.
Many
of
the
pesticides
included
in
today's
notice
are
included
among
the
first
group
of
reassessments.
In
reassessing
tolerances,
EPA
must
consider
the
aggregate
exposure
to
the
pesticide,
including
drinking
water;
cumulative
effects
from
other
pesticides
with
a
common
mode
of
toxicity;
whether
there
is
an
increased
susceptibility
from
exposure
to
the
pesticide
to
infants
and
children;
and
whether
the
pesticide
produces
an
effect
in
humans
similar
to
an
effect
produced
by
a
naturally
occurring
estrogen
or
other
endocrine
effects.

j.
Endocrine
disruptors.
A
list
of
contaminants
was
developed
which
included
those
suspected
of
having
adverse
effects
on
endocrine
function
(
see
Table
6).
For
several
years,
the
Agency
has
been
concerned
that
chemicals
may
be
disrupting
the
endocrine
(
i.
e.,
hormonal)
systems
of
humans
and
wildlife.
It
has
also
been
hypothesized
that
endocrine
disruption
might
result
in
cancer,
harm
to
male
and
female
reproductive
systems,
thyroid
damage,
or
other
adverse
consequences.
In
February
1997,
EPA
issued
an
assessment
and
analysis
of
this
concern
(
U.
S.
EPA,
1997a).
The
report
represents
an
interim
assessment
pending
a
more
extensive
review
expected
to
be
issued
by
the
National
Academy
of
Sciences
(
NAS)
later
this
year.
Table
6.
Contaminants
Identified
as
Suspected
of
Endocrine
Disruption
Amitrole
Benomyl
Dicofol
(
Kelthane)
Esfenvalerate
Ethylparathion
Fenvalerate
Kepone
Mancozeb
Metiram
Mirex
Nitrofen
Oxychlordane
Parathion
Permethrin
Synthetic
pyrethroids
Transnonachlor
Tributyltin
oxide
Vinclozolin
Zineb
Ziram
Octachlorostyrene
PBBs
Penta­
to
nonyl­
phenols
In
brief,
the
report
found
that
while
effects
have
been
found
in
laboratory
animal
studies,
a
causal
relationship
between
exposure
to
a
specific
environmental
agent
and
an
adverse
health
effect
in
humans
operating
via
endocrine
disruption
has
not
been
established,
with
a
few
exceptions.
The
exceptions
include
incidents
of
chemical
exposure
in
the
workplace
and
exposure
to
the
drug
DES.
Further
research
is
needed
before
such
effects
can
be
demonstrated.
Under
the
SDWA,
as
amended,
the
Agency
is
also
required
to
establish
a
program
to
screen
endocrine
disrupting
contaminants.
Additional
authority
to
assess
endocrine
disruptors
is
also
provided
through
the
recently
enacted
FQPA.
EPA's
Office
of
Prevention,
Pesticides,
and
Toxic
Substances
(
OPPTS)
has
the
Agency
lead
on
endocrine
disruptor
screening
and
testing
issues.
OPPTS
is
actively
engaged
in
research
and
regulatory
initiatives
to
respond
to
the
growing
scientific
and
public
concern
over
endocrine
disruptors.
The
Endocrine
Disruptor
Screening
and
Testing
Advisory
Committee
(
EDSTAC)
has
been
established
to
provide
advice
and
counsel
to
the
agency
in
implementing
a
screening
and
testing
strategy
required
under
the
FQPA
and
SDWA.
EDSTAC
is
composed
of
a
balanced
representation
from
industry,
government,
environmental
and
public
health
groups,
labor,
academia,
and
other
interested
stakeholders.
During
its
deliberations,
the
Committee
will
consider
human
health,
ecological,
estrogenic,
androgenic,
anti­
estrogenic,
antiandrogenic
and
thyroid
effects
of
pesticides,
industrial
chemicals,
and
important
mixtures.
EDSTAC
will
complete
its
recommendations
for
a
screening
and
testing
strategy
by
March,
1998.
The
recommendations
will
be
peer
reviewed
jointly
by
the
SAB
and
the
FIFRA
Scientific
Advisory
Panel.
EPA
is
also
involved
in
concurrent
effort
to
coordinate
activities
with
the
European
Union,
the
Organization
of
Economic
and
Community
Development,
and
the
United
Nations
Environmental
Program
concerning
global
research
programs,
and
international
harmonization
of
endocrine
disruptor
screening
and
testing
methods
for
chemicals
and
pesticides.
As
a
result,
pending
completion
of
the
EDSTAC's
recommendations
and
the
additional
review
of
endocrine
disruptors
by
the
NAS,
EPA
has
not
included
contaminants
for
initial
consideration
for
the
draft
CCL
based
solely
on
the
possibility
of
endocrine
disruption
(
although
several
contaminants
implicated
as
endocrine
disruptors
were
considered
for
other
reasons).
The
Agency
will
continue
to
follow
this
issue
closely
and
reconsider
this
category
of
potential
contaminants
in
the
development
of
future
CCLs.

Time
period
Covered:
Drinking
Water
Priority
List
from
1991,
IRIS
data
from1992,
non
target
analytes
list
from
1991,
CERCLA
list
from
1995,
stakeholder
responses
from
1996,
TRI
data
from
1994
and
OPP
list
1997.

Evaluation
Method:
Criteria
were
developed
by
the
NDWAC
Working
Group
for
use
in
screening
and
evaluating
chemical
contaminants
for
the
draft
CCL,
with
the
exception
of
aldicarbs,
nickel,
and
sulfate
which
are
discussed
in
section
III.
C.
3.
The
general
premises
of
the
criteria
were:
(
1)
The
contaminants
included
for
initial
consideration
be
those
on
EPA's
initial
list,
without
NPDWRs,
and
(
2)
that
occurrence,
or
anticipated
occurrence,
of
the
contaminant
be
evaluated
first,
before
evaluating
its
health
effects
information.
The
criteria,
presented
below,
were
used
to
screen
and
evaluate
chemical
contaminants
for
the
purpose
of
developing
today's
draft
CCL.
Data
used
to
evaluate
and
screen
contaminants
were
obtained
from
STORET,
the
Hazardous
Substances
Database
(
HSDB),
IRIS,
published
literature,
and
various
EPA
reports
and
documents.

These
criteria,
as
well
as
the
conceptual
approach
to
the
Contaminant
Identification
Method
(
CIM)
presented
in
the
December
2­
3,
1996
Stakeholders
meeting,
will
serve
as
the
basis
for
developing
a
more
robust
contaminant
identification
method
for
future
CCL
development.
The
search
results
on
each
element
of
the
criteria
for
contaminants
considered
during
the
development
of
the
CCL
can
be
found
by
using
the
Occurrence
Table,
the
Health
Table,
and
the
Comments
Table
included
in
the
docket
for
today's
notice.
a.
Criteria
for
occurrence.
For
the
occurrence
portion
of
the
criteria,
an
affirmative
response
to
any
of
the
following
elements
would
result
in
moving
to
the
health
portion
of
the
criteria
for
further
consideration.
If
all
of
the
occurrence
elements
had
a
negative
response,
the
contaminant
was
eliminated
from
further
consideration.
The
two
main
elements
to
the
occurrence
portion
of
the
criteria
were
as
follows:
(
1)
Was
the
contaminant
looked
for
and
found
in
drinking
water,
or
in
a
major
drinking
water
source,
or
in
ambient
water
at
levels
that
would
trigger
concern
about
human
health?
(
2)
if
the
contaminant
was
not
looked
for,
is
it
likely
to
be
found
in
water
based
on
surrogates
for
occurrence?
To
judge
whether
a
contaminant
was
looked
for
and
found
in
drinking
water,
according
to
the
criteria,
it
would
need
to
be
included
in
a
major
survey
which
was
defined
as
one
which
included
a
population
of
100,000
or
more,
2
or
more
states,
or
10
or
more
small
public
water
systems,
or
a
data
set
such
as
EPA's
Unregulated
Contaminants
Database.
To
judge
whether
a
contaminant
was
looked
for
and
found
in
a
major
drinking
water
source,
or
in
ambient
water,
any
source
of
occurrence
data
could
be
used.
A
source
of
drinking
water
was
considered
to
be
major
if
it
supplied
a
population
of
100,000
or
more,
or
2
or
more
states.
Levels
that
would
trigger
concern
about
human
health
were
defined
as
concentrations
in
samples
within
an
order
of
magnitude
of
the
level
that
is
likely
to
cause
health
effects,
or
at
least
\
1/
2\
of
samples
at
50%
of
level
that
is
likely
to
cause
health
effects.
Contaminants
were
considered
to
have
met
the
criteria
if
the
data
available
indicated
occurrence
at
a
population
of
100,000
or
more;
or
in
2
or
more
states;
or
in
10
or
more
small
public
water
systems
at
levels
that
would
trigger
concern
about
human
health.
If
the
contaminant
was
not
looked
for
using
the
data
available,
it
was
evaluated
to
determine
if
it
was
likely
to
be
found
in
water
based
on
surrogates
for
occurrence.
The
elements
considered
as
surrogates
for
occurrence
included:
TRI
releases,
or
production
volumes,
coupled
with
physicalchemical
properties,
or
the
OPP
GW
Risk
value.
In
order
for
a
contaminant
to
meet
this
criterion
as
likely
to
be
found
in
water
using
TRI,
the
release
to
surface
water
was
in
excess
of
400,000
pounds
per
year,
and
the
physical­
chemical
properties
indicated
persistence
&
mobility
of
the
contaminant.
The
quantity
of
400,000
pound
per
year
was
based
on
the
top
15
TRI
chemicals
with
the
largest
discharges
to
surface
water
as
reported
in
1995.
In
order
for
a
contaminant
to
meet
this
criterion
as
likely
to
be
found
in
water
using
production,
the
volume
was
in
excess
of
10
billion
pounds
per
year,
and
physical­
chemical
properties
indicated
persistence
and
mobility.
For
a
contaminant
to
meet
this
criteria
as
likely
to
be
found
in
water
using
OPP
GW
Risk,
the
value
was
2.0
or
greater.
However,
late
during
the
data
evaluation
and
screening
phase
of
the
CCL
development,
the
decision
was
made
to
defer
contaminants
identified
under
this
element
until
a
more
in­
depth
analysis
could
be
performed
that
would
include
risk
to
both
surface
and
ground
water,
and
a
component
to
address
health.
b.
Criteria
for
health.
For
the
health
portion
of
the
criteria,
an
affirmative
response
to
any
of
the
following
elements
resulted
in
including
the
contaminant
on
the
first
CCL,
if
it
also
met
the
occurrence
criteria.
A
negative
response
to
every
question
resulted
in
the
contaminant
being
eliminated
from
consideration
for
the
CCL.
The
health
portion
of
the
criteria
had
one
major
component;
was
there
evidence,
or
suspicion,
that
the
contaminant
causes
adverse
human
health
effects?
This
portion
of
the
criteria
was
met
if
a
contaminant
had
one
or
more
of
the
following
elements:
(
1)
Listed
by
California
Proposition
65,
(
2)
an
EPA
Health
Advisory,
(
3)
a
likely
(
based
on
animal
data)
or
known
(
based
on
human
data)
carcinogen
by
EPA
or
International
Agency
for
Research
on
Cancer
(
IARC),
(
4)
more
than
one
human
epidemiological
study
(
indicating
adverse
effects),
(
5)
an
oral
value
in
IRIS,
(
6)
regulated
in
drinking
water
by
another
industrial
country,
(
7)
a
member
of
a
chemical
family
of
known
toxicity,
or
(
8)
structural
activity
relationship
indicating
toxicity.
As
the
contaminants
were
being
screened
and
evaluated,
the
factors
for
health
which
proved
to
be
the
most
useful
were
those
that
provided
a
health
level
of
concern
as
a
concentration
that
could
be
compared
to
the
levels
of
occurrence
found
in
water,
such
as
an
EPA
Health
Advisory,
an
oral
value
in
IRIS,
or
a
regulatory
level
from
another
industrial
country.
Being
listed
by
California
Proposition
65,
or
a
member
of
a
chemical
family
of
known
toxicity
had
limited
utility
in
determining
which
contaminants
to
include
on
the
CCL.

Results:
The
final
candidate
contaminant
list
includes
50
chemical
and
10
microbial
contaminants
(
see
Table
1,
attached).
It
also
identifies
data
gaps
and
next
steps
for
future
lists
(
see
Table
2,
attached).

Short
Term
Followup:
Contact
ODWGW
for
progress
of
2003
list
and
fulfillment
of
data
gap
research
priorities.

Long
Term
Followup:
Can
we
coordinate
these
two
planning
processes?
Table
6.
Contaminants
Identified
as
Suspected
of
Endocrine
Disruption
Amitrole
Benomyl
Dicofol
(
Kelthane)
Esfenvalerate
Ethylparathion
Fenvalerate
Kepone
Mancozeb
Metiram
Mirex
Nitrofen
Oxychlordane
Parathion
Permethrin
Synthetic
pyrethroids
Transnonachlor
Tributyltin
oxide
Vinclozolin
Zineb
Ziram
Octachlorostyrene
PBBs
Penta­
to
nonyl­
phenols
Table
1.­­
Drinking
Water
Contaminant
Candidate
List
­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­
Microbiological
contaminants
­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­
Acanthamoeba
(
guidance
expected
for
contact
lens
wearers)
Adenoviruses
Aeromonas
hydrophila
Caliciviruses
Coxsackieviruses
Cyanobacteria
(
blue­
green
algae),
other
freshwater
algae,
and
their
toxins
Echoviruses
Helicobacter
pylori
Microsporidia
(
Enterocytozoon
&
Septata)
Mycobacterium
avium
intracellulare
(
MAC)
­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­

Chemical
contaminants
CASRN
1,1,2,2­
tetrachloroethane...............................
79­
34­
5
1,2,4­
trimethylbenzene..................................
95­
63­
6
1,1­
dichloroethane......................................
75­
34­
3
1,1­
dichloropropene.....................................
563­
58­
6
1,2­
diphenylhydrazine...................................
122­
66­
7
1,3­
dichloropropane.....................................
142­
28­
9
1,3­
Dichloropropene.....................................
542­
75­
6
[[
Page
10276]]

2,4,6­
trichlorophenol...................................
88­
06­
2
2,2­
dichloropropane.....................................
594­
20­
7
2,4­
dichlorophenol......................................
120­
83­
2
2,4­
dinitrophenol.......................................
51­
28­
5
2,4­
dinitrotoluene......................................
121­
14­
2
2,6­
dinitrotoluene......................................
606­
20­
2
2­
methyl­
Phenol
(
o­
cresol)..............................
95­
48­
7
Acetochlor..............................................
34256­
82­
1
Alachlor
ESA
&
other
acetanilide
pesticide
degradation
products...............................................
N/
A
Aldrin..................................................
309­
00­
2
Aluminum................................................
7429­
90­
5
Boron...................................................
7440­
42­
8
Bromobenzene............................................
108­
86­
1
DCPA
mono­
acid
degradate................................
887­
54­
7
DCPA
di­
acid
degradate..................................
2136­
79­
0
DDE.....................................................
72­
55­
9
Diazinon................................................
333­
41­
5
Dieldrin................................................
60­
57­
1
Disulfoton..............................................
298­
04­
4
Diuron..................................................
330­
54­
1
EPTC
(
s­
ethyl­
dipropylthiocarbamate)....................
759­
94­
4
Fonofos.................................................
944­
22­
9
Hexachlorobutadiene.....................................
87­
68­
3
p­
Isopropyltoluene
(
p­
cymene)...........................
99­
87­
6
Linuron.................................................
330­
55­
2
Manganese...............................................
7439­
96­
5
Methyl
bromide..........................................
74­
83­
9
Methyl­
t­
butyl
ether
(
MTBE).............................
1634­
04­
4
Metolachlor.............................................
51218­
45­
2
Metribuzin..............................................
21087­
64­
9
Molinate................................................
2212­
67­
1
Naphthalene.............................................
91­
20­
3
Nitrobenzene............................................
98­
95­
3
Organotins..............................................
N/
A
Perchlorate.............................................
N/
A
Prometon................................................
1610­
18­
0
RDX.....................................................
121­
82­
4
Sodium..................................................
7440­
23­
5
Sulfate.................................................
14808­
79­
8
Terbacil................................................
5902­
51­
2
Terbufos................................................
13071­
79­
9
Triazines
&
degradation
products
of
triazines
(
including,
but
not
limited
to
Cyanazine
21725­
46­
2,
and
atrazine­
desethyl
6190­
65­
4).......................
Vanadium................................................
7440­
62­
2
­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­
