GAO
United
States
General
Accounting
Office
Congressional
Requesters
May
2000
TOXIC
CHEMICALS
Long­
Term
Coordinated
Strategy
Needed
to
Measure
Exposures
in
Humans
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Data
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Contents
Letter
3
Appendixes
Appendix
I:
Objectives,
Scope,
and
Methodology
46
Appendix
II:
Reported
Gaps
in
Human
Exposure
Data
and
History
of
Federal
Efforts
52
Appendix
III:
Survey
of
State
Environmental
Health
Officials
and
Results
62
Appendix
IV:
Comments
From
the
Department
of
Health
and
Human
Services
68
Appendix
V:
Comments
From
the
Environmental
Protection
Agency
73
Appendix
VI:
Major
Contributors
to
This
Report
78
Tables
Table
1:
Extent
to
Which
Human
Exposure
Data
Are
Collected
for
Potentially
Harmful
Chemicals
Through
NHANES
or
the
NHEXAS
Pilot
Surveys
14
Table
2:
Prevalence
of
Elevated
Blood
Lead
Levels
in
Children
Ages
1
Through
5,
by
Selected
Demographic
Characteristics
(
NHANES,
1991
Through
1994)
18
Table
3:
Examples
of
How
State
Officials
Use
Human
Exposure
Data
23
Table
4:
Examples
of
Reports
Calling
for
Coordination
in
Environmental
Health
32
Table
5:
Number
of
Chemicals
and
Time
Frames
for
Select
Federal
Efforts
55
Contents
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Abbreviations
ATSDR
Agency
for
Toxic
Substances
and
Disease
Registry
CDC
Centers
for
Disease
Control
and
Prevention
DP­
HANES
Defined
Population
Health
and
Nutrition
Examination
Survey
EPA
Environmental
Protection
Agency
HHS
Department
of
Health
and
Human
Services
MTBE
methyl
t­
butyl
ether
NCEH
National
Center
for
Environmental
Health
NCHS
National
Center
for
Health
Statistics
NHANES
National
Health
and
Nutrition
Examination
Survey
NHATS
National
Human
Adipose
Tissue
Survey
NHEXAS
National
Human
Exposure
Assessment
Survey
NIEHS
National
Institute
of
Environmental
Health
Sciences
NIH
National
Institutes
of
Health
NRC
National
Research
Council
NTP
National
Toxicology
Program
PBT
persistent,
bioaccumulative,
and
toxic
PCB
polychlorinated
biphenyls
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United
States
General
Accounting
Office
Washington,
D.
C.
20548
Health,
Education,
and
Human
Services
Division
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Letter
May
2,
2000
Congressional
Requesters
State
and
local
officials
report
continuing
public
concern
over
the
health
risks
posed
by
exposures
to
toxic
chemicals,
ranging
from
heavy
metals
such
as
arsenic
found
at
national
hazardous
waste
sites
to
common
pesticides
used
in
and
around
the
home.
For
example,
increasing
rates
of
cancer
in
various
communities
have
prompted
questions
about
the
potential
link
to
residues
from
pesticides,
indoor
air
pollutants,
and
other
toxic
chemicals.
Historically,
estimates
of
human
exposure
to
toxic
chemicals
have
been
based
on
the
concentration
of
these
chemicals
in
environmental
media
 
such
as
air,
water,
and
food
 
along
with
assumptions
about
how
people
are
exposed.
Federal
monitoring
efforts
have
primarily
focused
on
this
type
of
measurement.
However,
according
to
public
health
experts,
measurements
of
internal
doses
of
exposure
 
actual
levels
of
chemicals
or
their
metabolites1
in
human
tissues
such
as
blood
or
urine
 
can
be
a
more
useful
measure
of
exposure
for
some
purposes.

Over
the
past
decade,
advances
in
laboratory
technology
have
provided
new
tools
for
measuring
a
broad
range
of
chemicals
in
human
tissues
 
tools
that
can
help
researchers
and
health
officials
assess
how
much
of
a
chemical
has
been
absorbed
in
the
body
and
provide
more
accurate
measurements
of
exposure
to
relate
to
potential
health
risks.
When
gathered
for
the
U.
S.
population,
such
data
can
help
identify
new
or
previously
unrecognized
hazards
related
to
chemical
substances
found
in
the
environment,
monitor
changes
in
exposures
over
time,
and
establish
the
distribution
of
exposure
levels
among
the
general
population.
These
data
can
also
help
identify
subpopulations
 
such
as
children,
low­
income
groups,
or
ethnic
minorities
 
that
might
be
at
increased
risk
because
they
face
particularly
high
levels
of
exposure.
State
and
local
health
officials
can
use
information
on
typical
exposures
in
the
general
population
to
help
assess
environmental
health
risks
for
specific
sites
or
populations
within
their
borders
and
to
keep
local
residents
informed.
For
example,
local
officials
in
one
community
collected
exposure
measurements
before,

1Metabolites
result
from
the
interaction
of
the
chemicals
with
enzymes
or
other
chemicals
inside
the
body.
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during,
and
after
the
burning
of
arsenic­
contaminated
soil
and
found
that
no
excess
exposure
 
as
compared
to
typical
levels
found
in
the
population
 
had
occurred.

In
light
of
the
potential
benefits
offered
by
these
new
technologies,
you
asked
us
to
review
efforts
to
collect
and
use
such
information
at
both
the
state
and
federal
levels.
Specifically,
you
asked
us
to
(
1)
determine
the
extent
to
which
state
and
federal
agencies
 
in
particular,
the
Department
of
Health
and
Human
Services
(
HHS)
and
the
Environmental
Protection
Agency
(
EPA)
 
collect
human
exposure
data2
on
potentially
harmful
chemicals,
including
data
to
identify
at­
risk
populations,
and
(
2)
identify
the
main
barriers
hindering
further
progress
in
such
efforts.

We
compiled
a
list
of
more
than
1,400
naturally
occurring
and
manmade
chemicals
considered
by
HHS,
EPA,
and
other
entities
to
pose
a
potential
threat
to
human
health.
These
included
chemicals
prioritized
for
safety
testing
(
based
on
EPA's
findings
that
the
chemicals
may
present
unreasonable
health
risks),
chemicals
linked
to
cancer,
toxic
chemicals
frequently
found
at
Superfund
sites,
and
certain
pesticides
monitored
in
foods
or
thought
to
be
potentially
harmful
to
humans.
For
these
chemicals,
we
assessed
the
extent
to
which
major
HHS
and
EPA
survey
efforts
 
specifically
HHS'
National
Health
and
Nutrition
Examination
Survey
(
NHANES)
and
EPA's
National
Human
Exposure
Assessment
Survey
(
NHEXAS)
phase
I
(
pilot
surveys)
 
were
collecting
human
exposure
data.
We
also
surveyed
93
environmental
health
officials
in
50
states
and
the
District
of
Columbia,
receiving
responses
from
81
officials
in
48
states
for
a
response
rate
of
87
percent.
At
the
federal
level,
we
focused
on
survey
data
collected
for
the
general
(
non­
occupationally­
exposed)
population.
We
excluded
federally
sponsored
academic
and
private
sector
research.
Appendix
I
explains
our
scope
and
methodology
in
more
detail.
We
conducted
our
work
from
March
1999
through
March
2000
in
accordance
with
generally
accepted
government
auditing
standards.

2The
scientific
community
uses
varying
terminology
when
referring
to
human
exposures.
Often,
external
contacts
with
chemicals
are
defined
as
"
exposures,"
and
internal
measurements
of
exposure
are
referred
to
as
"
doses."
Doses
are
also
considered
a
measure
of
exposure.
Our
review
focused
primarily
on
efforts
to
gather
internal
exposure
measurements
through
human
tissue
in
the
non­
occupationally­
exposed
population.
To
simplify
reporting,
we
are
referring
to
such
internal
exposure
measurements
as
"
human
exposure"
data.
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Results
in
Brief
Federal
and
state
efforts
to
collect
human
exposure
data
are
limited,
despite
some
recent
expansions.
HHS
and
EPA
have
been
able
to
take
advantage
of
improved
technology
to
measure
exposures
for
more
people
and
for
a
broader
range
of
chemicals.
Still,
with
existing
resources,
HHS
and
EPA
surveys
together
measure
in
the
general
population
only
about
6
percent
of
the
more
than
1,400
toxic
chemicals
in
our
review.
For
those
toxic
chemicals
that
we
reviewed,
the
portion
measured
ranged
from
2
percent
of
chemicals
prioritized
for
safety
testing
to
about
23
percent
of
those
chemicals
most
often
found
at
Superfund
sites
and
considered
to
pose
a
significant
threat
to
human
health.
Even
for
those
chemicals
that
are
measured,
information
is
often
insufficient
to
identify
smaller
population
groups
at
high
risk,
such
as
children
in
inner
cities
and
people
living
in
polluted
locations
who
may
have
particularly
high
exposures.
At
the
state
level,
efforts
are
similarly
limited.
Almost
all
state
officials
who
we
surveyed
said
they
highly
valued
human
exposure
data
for
populations
within
their
borders,
and
many
provided
specific
examples
of
how
such
data
have
provided
useful
information
for
interpreting
citizens'
health
risks
and
guiding
public
health
actions.
For
example,
state
officials
in
nine
states
used
human
samples
not
only
to
identify
who
was
exposed
to
a
toxic
pesticide
illegally
sprayed
in
citizens'
homes,
but
to
identify
houses
most
in
need
of
clean­
up.
Despite
this
perceived
value,
most
officials
reported
that
they
were
unable
to
collect
or
use
human
exposure
data
in
most
of
the
cases
where
they
thought
it
was
important
to
do
so.

Three
main
barriers
limit
federal
and
state
agencies'
abilities
to
make
more
progress.
First,
federal
and
state
laboratories
often
lack
the
capacity
to
conduct
measurements
needed
to
collect
human
exposure
data;
additionally,
for
most
of
the
chemicals
on
our
list,
no
laboratory
method
has
been
developed
for
measuring
the
chemical
levels
in
human
tissues.
The
second
barrier,
particularly
voiced
by
state
officials,
relates
to
the
lack
of
information
to
help
set
test
results
in
context.
Public
health
officials
said
they
need
more
information
on
typical
exposures
in
the
general
population
so
that
they
can
compare
this
information
with
people's
levels
at
specific
sites
or
with
specific
populations
in
their
states.
They
also
said
they
needed
more
research
to
relate
exposure
levels
to
health
effects
for
the
chemicals
of
concern
in
their
states.
The
third
barrier,
of
particular
concern
at
the
federal
level,
is
that
coordinated,
long­
term
planning
among
federal
agencies
has
been
lacking,
partly
because
of
sporadic
agency
commitments
to
human
exposure
measurement
and
monitoring.
HHS
and
EPA
officials
indicated
that
they
have
been
discussing
the
merits
of
establishing
a
coordinated
interagency
human
exposure
program,
but
they
have
not
yet
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formalized
or
agreed
upon
a
long­
term
strategy.
A
long­
term
coordinated
strategy
should
also
ensure
adequate
linkages
between
collection
efforts
and
agency
goals,
provide
a
framework
for
coordinating
data
collection
efforts
that
considers
individual
agencies'
needs
and
expertise,
provide
a
framework
for
identifying
at­
risk
populations,
and
consider
states'
needs
for
information.
To
address
these
needs,
we
are
recommending
that
the
Secretary
of
HHS
and
the
Administrator
of
EPA
develop
a
coordinated
federal
strategy
for
the
short­
and
long­
term
monitoring
and
reporting
of
human
exposures
to
potentially
toxic
chemicals.

Background
EPA
projects
a
continuing
upward
trend
in
environmental
compliance
costs
for
pollution
control
measures,
amounting
to
an
estimated
$
148
billion
this
year.
Hundreds
of
millions
of
dollars
are
spent
monitoring
levels
of
toxic
chemicals
in
the
environment
 
for
example,
approximately
$
139
million
of
federal
funding
supported
national
air­
quality
monitoring
networks
in
the
United
States
in
fiscal
year
1999.3
Despite
these
expenditures,
what
often
is
not
known
is
the
extent
to
which
people
are
exposed
to
potentially
harmful
chemicals
in
their
daily
lives,
the
chemicals
to
which
they
are
most
often
exposed,
the
levels
of
such
exposure,
how
exposures
change
over
time
in
relation
to
regulatory
policies,
and
the
sources
of
exposure.
Policymakers,
regulators,
researchers,
and
public
health
officials
must
often
rely
on
estimates
of
human
exposure
levels
for
the
general
population
or
for
smaller
groups
thought
to
be
at
risk.
Such
estimates
are
often
derived
from
data
showing
the
extent
the
chemicals
are
found
in
the
air,
water,
food,
or
other
environmental
media
and
assumptions
about
how
and
at
what
rate
the
body
absorbs
the
chemicals
it
contacts.
A
variety
of
methods
for
measuring
exposures
are
considered
to
be
more
direct
than
those
that
measure
chemicals
in
the
ambient
environment.
These
methods
measure
exposures
in
people's
more
immediate
environments
and
include
tools
such
as
personal
air
monitors,
which
measure
chemicals
that
may
be
inhaled.
For
several
chemicals
and
purposes,
measuring
internal
exposure
levels
in
human
tissues
is
considered
the
most
useful
and
accurate
measure
and
an
important
piece
of
the
information
needed
to
link
contaminants
in
the
environment
with
adverse
health
effects.

3
The
Role
of
Monitoring
Networks
in
the
Management
of
the
Nation's
Air
Quality,
National
Science
and
Technology
Council,
Committee
on
Environment
and
Natural
Resources,
Air
Quality
Research
Subcommittee
(
Mar.
1999).
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While
officials
may
be
able
to
collect
internal
exposure
levels
at
a
local
level,
the
results
are
difficult
to
interpret
without
information
such
as
comparative
data
to
show
what
exposure
levels
might
be
considered
high
or
research
findings
linking
exposure
levels
to
specific
health
effects.
Because
of
the
need
for
improved
data
on
actual
human
exposures
found
in
the
general
population,
the
National
Research
Council
(
NRC),
an
arm
of
the
National
Academy
of
Sciences,
recommended
in
1991
that
the
nation
adopt
a
new
program
to
monitor
chemical
residues
in
human
tissues,
such
as
blood.
NRC
noted
that
determining
the
concentrations
of
specific
chemicals
in
human
tissues
could
serve
to
integrate
many
kinds
of
human
exposures
across
media
such
as
air,
water,
or
food
and
over
time.
As
one
component
of
an
effort
to
manage
environmental
quality
and
protect
public
health,
NRC
reported
that
a
well­
designed
national
program
for
monitoring
toxic
chemicals
in
human
tissues
was
needed.
4
NRC
pointed
out
that
human
exposure
data
could
be
used
to
help
monitor
changes
in
the
population's
exposure
to
chemicals
and
identify
population
groups
 
by
factors
such
as
age
or
geographic
location
 
that
might
be
at
increased
risk
because
they
face
higher
levels
of
exposure.

Direct
biological
monitoring
of
human
exposure
to
chemicals
has
been
made
increasingly
possible
by
recent
advancements
in
analytical
chemistry
and
molecular
biology.
Methods
have
been
developed
to
measure
smaller
levels
of
toxicants
in
body
tissues
and
to
do
so
with
smaller
sample
amounts.
5
For
example,
a
few
years
ago
a
laboratory
would
need
100
milliliters
of
blood
to
detect
dioxins
in
the
part­
per­
billion
range.
New
test
methods
use
less
than
10
milliliters
and
are
capable
of
detecting
concentrations
in
the
parts­
per­
trillion
range.
Single
samples
can
also
now
be
used
to
detect
low
concentrations
of
multiple
chemicals.
Since
1995,
for
example,
laboratory
methods
have
been
developed
to
detect
polycyclic
aromatic
hydrocarbons,
a
group
of
more
than
100
chemicals
formed
during
4According
to
NRC,
human
monitoring
data
alone
can
signal
the
need
to
conduct
studies
on
specific
environmental
chemicals,
but
these
data
are
best
viewed
as
one
component
of
a
comprehensive
environmental
monitoring
program.
Human
measurements
are
best
supplemented
with
knowledge
of
contaminant
sources,
environmental
pathways,
environmental
concentrations,
time
patterns
and
locations
of
exposure,
routes
of
entry
into
the
body,
material
toxicity,
and
latency.
See
NRC,
Commission
on
Life
Sciences,
Monitoring
Human
Tissues
for
Toxic
Substances(
Washington,
D.
C.:
National
Academy
Press,
1991).

5Other
human
biological
tissues
that
might
be
used
for
measurements
of
chemical
concentrations
include
fat
tissue,
breast
milk,
semen,
urine,
liver
specimens,
hair,
fingernails,
or
saliva.
Human
breath
has
also
been
used
to
measure
exposure
to
certain
chemicals.
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the
incomplete
burning
of
coal,
oil,
gas,
garbage,
tobacco,
and
other
substances.

Lead
is
an
example
of
a
chemical
that
has
been
monitored
extensively
by
measuring
absorption
into
human
tissues
 
specifically,
lead
levels
in
the
blood.
Elevated
levels
of
lead
in
the
blood
can
cause
learning
problems
and,
at
extreme
levels,
result
in
serious
brain
or
kidney
damage.
Data
on
blood
lead
levels
have
been
collected
for
the
national
population
since
1976.
Public
health
officials,
researchers,
and
others
have
used
lead
exposure
data
from
large­
and
small­
scale
studies
in
many
ways
to
identify
at­
risk
populations,
evaluate
regulatory
actions,
improve
the
models
used
to
estimate
exposure,
and
identify
significant
sources
of
preventable
exposure,
as
shown
in
the
following
examples.

°
Identifying
at­
risk
populations:
National
blood
lead
data
revealed
that
low­
income
children
living
in
houses
built
before
1946
had
a
prevalence
of
elevated
blood
lead
levels
of
16.4
percent
as
compared
to
4.4
percent
for
all
children
ages
1
through
5;
non­
Hispanic
black
children
in
similar
housing
had
a
prevalence
of
21.9
percent
 
the
highest
risk
of
elevated
blood
lead
levels
of
any
demographic
group.
Using
this
information,
state
and
local
health
officials
can
more
effectively
target
screening
and
treatment
efforts.
°
Establishing
and
evaluating
public
health­
related
policies:
In
the
1980s,
EPA
was
considering
whether
or
not
to
make
permanent
a
temporary
ban
on
lead
in
gasoline.
National
data
on
lead
exposure
showed
a
decline
in
average
blood
lead
levels
that
corresponded
to
the
declining
amounts
of
lead
in
gasoline.
Based
on
this
and
other
information,
EPA
strengthened
its
restrictions
on
lead
in
gasoline
and
required
a
more
rapid
removal
of
lead
from
gasoline.
°
Improving
models
used
to
estimate
exposure:
Experts
indicate
that
an
increasingly
important
use
of
human
exposure
data
has
been
as
a
"
reality
check"
on
other
indexes
of
exposure,
such
as
questionnaires
about
activities
or
work
histories,
to
ascertain
whether
exposures
may
have
occurred.
For
example,
prior
to
the
decision
to
phase
out
lead
in
gasoline,
exposure
models
suggested
that
eliminating
lead
in
gasoline
would
have
only
a
slight
effect
on
blood
lead
levels,
while
actual
testing
showed
a
more
dramatic
effect.
°
Identifying
key
sources
of
exposure:
When
combined
with
other
exposure
data,
exposure
measurements
can
help
reveal
the
source
of
the
exposure
 
an
essential
step
in
developing
and
monitoring
intervention
strategies
designed
to
reduce
or
eliminate
harmful
exposures.
For
example,
when
no
evidence
of
lead
paint
 
the
most
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common
source
of
lead
contamination
 
was
found
in
the
home
of
a
child
whose
blood
showed
abnormal
levels
of
lead,
public
health
officials
were
baffled.
Observational
data
on
how
and
where
the
child
spent
time
and
environmental
data
from
the
surfaces
most
often
encountered
revealed
that
lead­
contaminated
stuffing
in
a
toy
the
child
chewed
likely
accounted
for
the
high
exposure.
The
child's
blood
lead
level
declined
when
the
contaminated
toy
was
removed.

While
lead
is
unique
among
chemicals
in
that
it
has
been
extensively
studied
 
decades
of
research
has
shown
its
harmful
effects
at
increasingly
lower
levels
 
such
research
has
been
possible
in
part
because
of
laboratory
advances
in
measurement
technology.
Over
the
years,
as
technology
improved
the
ability
to
measure
smaller
and
smaller
amounts
of
lead
in
the
bloodstream,
researchers
have
been
able
to
identify
increasingly
subtle
adverse
effects
by
linking
blood
lead
levels
and
changes
in
neurobehavioral
functioning.

Current
Measurement
Efforts
Cover
Few
Chemicals
and
Situations
Although
HHS
and
EPA
each
are
expanding
their
survey
efforts
to
use
new
technologies
and
measure
a
broader
range
of
exposures
in
the
national
population,
their
measurement
efforts
cover
a
limited
portion
of
the
more
than
1,400
potentially
harmful
chemicals
we
reviewed.
These
surveys
also
remain
of
limited
value
for
identifying
at­
risk
populations,
because
in
the
case
of
their
survey
efforts,
sample
sizes
to
date
have
been
insufficient
 
and,
for
most
chemicals,
not
representative
of
the
general
population.
In
addition,
federal
efforts
to
help
assess
potential
disproportionate
exposures
by
collecting
data
on
communities
living
near
Superfund
sites
have
been
limited
to
few
locations.
State
agencies
reported
that
their
efforts
are
also
limited,
despite
the
importance
they
place
on
using
such
data
in
their
studies
of
population­
or
site­
specific
situations
within
their
borders.
According
to
state
environmental
health
officials,
they
are
often
unable
to
collect
these
data.

Federal
Efforts
Are
Expanding
In
our
examination
of
the
HHS
and
EPA
surveys,
we
found
that
the
types
of
chemicals
measured
have
recently
increased.
For
the
past
40
years,
HHS'
Centers
for
Disease
Control
and
Prevention
(
CDC)
has
collected
through
a
survey
nationally
representative
data
on
the
health
and
nutrition
of
the
U.
S.
population.
Exposure
measurements
are
one
component
of
this
survey.
In
the
mid­
1990s,
EPA's
Office
of
Research
and
Development
initiated
a
human
exposure
survey,
which
is
currently
in
its
pilot
phase
in
three
locations
across
the
country.
A
third
more
recent
effort
to
monitor
human
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exposures
to
select
chemicals
was
initiated
in
1996
by
HHS'
National
Institute
of
Environmental
Health
Sciences
(
NIEHS)
of
the
National
Institutes
of
Health
(
NIH).
For
each
of
these
federal
efforts,
laboratory
measurements
are
largely
conducted
by
the
laboratory
at
CDC's
National
Center
for
Environmental
Health,
which
also
developed
many
of
the
methods
for
performing
these
measurements.

CDC's
National
Health
and
Nutrition
Examination
Survey
CDC
collects
human
exposure
data
as
part
of
NHANES,
which
has
been
conducted
periodically
since
1960
and,
beginning
in
1999,
has
been
conducted
annually.
NHANES
monitors
trends
in
health
status
by
conducting
interviews
and
physical
assessments
on
a
nationally
representative
sample
of
about
5,000
people
per
year.
NHANES
collects
blood
and
urine
samples
for
many
purposes,
such
as
assessing
cholesterol
levels
and
the
prevalence
of
diabetes.
Since
1976,
these
samples
have
also
been
used
to
measure
exposure
to
selected
chemicals,
and
excess
samples
are
banked
for
future
research.
In
the
past,
CDC's
human
exposure
monitoring
efforts
have
focused
largely
on
lead,
cadmium,
and
a
few
pesticides
and
volatile
organic
compounds
 
chemical
compounds
which
include
a
number
of
animal
and
known
or
suspected
human
carcinogens
found
in
tobacco
smoke,
building
supplies,
and
consumer
products.
6
Starting
with
the
1999
NHANES,
CDC
proposed
to
measure
up
to
210
chemicals
in
human
tissues
as
staff
and
other
resources
permitted.
These
chemicals
include
metals
such
as
mercury,
which
at
high
levels
may
damage
the
brain,
kidneys,
and
developing
fetus;
polyaromatic
hydrocarbons
(
a
group
of
compounds
found
in
sources
such
as
foods
that
have
been
grilled);
and
volatile
organic
compounds,
such
as
benzene.
At
the
time
of
our
review,
a
CDC
official
indicated
that
resources
allowed
them
to
include
about
74
chemicals
for
1999
and
2000.
The
estimated
marginal
costs
for
the
environmental
exposure­
related
components
of
the
NHANES
1999
survey
were
about
$
5
million.

EPA's
National
Human
Exposure
Assessment
Survey
To
expand
upon
and
replace
its
National
Human
Adipose
Tissue
Survey
(
NHATS)
 
a
tissue
monitoring
program,
which
ended
in
1992
 
EPA
6Special
reference
studies
supported
by
the
Agency
for
Toxic
Substances
and
Disease
Registry
were
also
conducted
on
nonrepresentative
samples
of
a
portion
of
the
people
participating
in
the
most
recently
completed
segment
of
NHANES
(
conducted
from
1991
through
1994).
These
special
studies
assessed
exposure
to
45
pesticides
and
volatile
organic
compounds.
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initiated
in
1993
pilot
surveys
for
NHEXAS
in
three
regions
of
the
country.
7
A
goal
of
the
NHEXAS
pilots
is
to
obtain
knowledge
on
the
population's
distribution
of
total
exposure
to
several
classes
of
chemicals
and
to
test
the
feasibility
of
collecting
representative
survey
data
on
people's
total
exposures.
NHATS
focused
on
monitoring
human
fat
tissues
for
persistent
organochlorine
pesticides
and
polychlorinated
biphenyls
(
PCB);
NHEXAS
has
broadened
this
focus
in
two
ways.
First,
in
addition
to
measuring
chemical
levels
in
samples
such
as
blood
or
urine,
the
NHEXAS
pilot
surveys
included
measurements
of
chemicals
in
air,
foods
and
beverages,
water,
and
dust
in
individuals'
personal
external
and
internal
environments.
To
conduct
these
measurements,
the
pilot
surveys
used
tools
such
as
questionnaires,
activity
diaries,
air­
monitoring
badges
worn
by
the
individual
or
other
air­
monitoring
devices,
and
tap
and
drinking
water
and
food
samples.
Such
data
are
important
for
purposes
such
as
identifying
the
most
important
sources
or
routes
of
exposure
and
for
taking
actions
to
reduce
or
prevent
exposures.
Second,
the
NHEXAS
pilot
surveys
included
more
types
of
chemicals
than
pesticides,
such
as
lead
and
other
heavy
metals.
The
NHEXAS
pilots,
however,
included
fewer
chemicals
than
its
predecessor
 
which
measured
about
130
pesticides
and
PCBs
in
human
fat
tissue
 
in
part
because
monitoring
levels
of
any
given
chemical
in
personal
environments
and
in
human
tissues
requires
significantly
more
laboratory
measurements
for
the
same
chemical.
EPA's
NHEXAS
pilot
surveys,
which
have
tested
biological
samples
from
about
460
participants,
have
collectively
measured
up
to
46
chemicals,
including
pesticides,
heavy
metals,
and
volatile
organic
compounds
in
blood,
urine,
or
hair.
Once
data
from
these
pilot
surveys
have
been
further
analyzed,
EPA
intends
to
assess
the
feasibility
and
cost
of
conducting
a
national
effort
to
collect
total
exposure
data.
To
date,
EPA
has
invested
about
$
20
million
to
support
the
pilot
surveys.
Very
preliminary
estimates
by
EPA
for
a
national
survey
range
from
$
20
million
to
$
30
million
per
year
over
10
years
or
more.

National
Institute
of
Environmental
Health
Sciences'
Human
Exposure
Initiative
In
1996,
NIEHS
began
an
initiative
to
collect
human
exposure
data.
This
initiative
was
started
as
a
collaboration
between
NIEHS
and
CDC
to
improve
understanding
of
human
exposures
to
hormonally
active
agents
 
also
called
"
environmental
endocrine
disrupters"
 
for
the
national
7Specifically,
pilot
surveys
were
conducted
in
Arizona,
Maryland,
and
EPA's
region
5
(
Illinois,
Indiana,
Michigan,
Minnesota,
Ohio,
and
Wisconsin).
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population.
8
The
effort
was
intended
to
build
upon
the
chemical
monitoring
in
NHANES
by
supporting
the
development
of
laboratory
methods
and
measurement
of
previously
unmeasured
chemicals
in
human
tissues
collected
from
NHANES
and
other
studies.
NIEHS
and
CDC
signed
an
interagency
agreement,
under
which
CDC
will
develop
methods
for
measuring
and
will
measure
in
blood,
urine,
or
both
up
to
80
chemicals
thought
to
be
hormonally
active
agents.
For
this
effort,
CDC
obtained
samples
of
about
200
people
 
most
of
whom
are
from
the
ongoing
sampling
of
the
general
population
under
NHANES.

In
1999,
officials
of
NIEHS
and
the
National
Toxicology
Program
(
NTP)
 
an
interagency
effort
to
coordinate
toxicological
research
and
testing
activities
of
HHS,
which
is
administratively
housed
at
NIEHS
 
proposed
to
expand
upon
the
initial
collaboration
and
formalized
the
undertaking
as
the
Human
Exposure
Initiative.
Specifically,
they
proposed
a
broader
interagency
effort
to
quantify
human
internal
exposures
to
chemicals
released
into
the
environment
and
workplace.
One
significant
purpose
of
this
effort
was
to
help
prioritize
those
chemicals
and
chemical
mixtures
to
be
studied
by
NTP,
recognizing
the
limited
resources
available
for
toxicological
testing
and
the
need
for
better
information
to
prioritize
which
chemicals
should
be
tested.
According
to
NTP
officials,
although
NTP
is
the
nation's
largest
federal
toxicology
testing
program,
it
can
initiate
only
10
long­
term
cancer
studies
and
10
reproductive
studies
per
year.
9
NIEHS
provided
a
list
of
131
chemicals
it
hoped
would
be
measured
through
this
expanded
effort.
At
the
time
of
our
review,
however,
program
officials
told
us
that
NIEHS
had
not
published
data
from
the
chemicals
CDC
had
measured
under
this
agreement,
and
CDC
was
developing
the
laboratory
methods
needed
to
measure
many
of
the
chemicals
identified
by
NIEHS
as
8The
concern
about
endocrine
disrupters
originated
from
the
finding
that
some
synthetic
chemicals
in
the
environment
are
associated
with
adverse
reproductive
and
developmental
effects
in
wildlife
and
mimic
the
actions
of
female
hormones.
According
to
NRC,
although
it
is
clear
that
exposures
to
hormonally
active
agents
at
high
concentrations
can
affect
wildlife
and
human
health,
the
extent
of
harm
caused
by
exposure
to
these
compounds
in
concentrations
that
are
common
in
the
environment
is
debated.
See
NRC,
Commission
on
Life
Sciences,
Hormonally
Active
Agents
in
the
Environment(
Washington,
D.
C.:
National
Academy
Press,
July
1999).

9According
to
NTP
officials,
chemicals
are
tested
for
cancer
and
noncancer
endpoints
 
including
effects
on
reproduction,
development,
nervous
system,
and
immune
systems
 
using
traditional
bioassays
as
well
as
newly
validated
tests.
Validation
of
new
tests
is
achieved
through
an
NTP
interagency
center
involving
15
federal
agencies
or
institutes.
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10
(
For
more
information
on
NHANES,
NHATS,
NHEXAS,
and
NIEHS'
Human
Exposure
Initiative,
see
app.
II.)

Despite
Expansion,
Chemicals
Covered
in
Exposure
Measurements
Remains
Limited
Despite
these
expanded
efforts,
NHANES
and
the
NHEXAS
pilot
surveys
cover
only
about
6
percent
(
or
81)
of
the
1,456
potentially
harmful
chemicals
in
our
review.
We
compared
the
chemicals
measured
by
these
surveys
to
eight
selected
lists
of
chemicals
of
concern.
11
Our
selection
was
based,
in
part,
on
our
assessment
and
input
from
experts
that
these
lists
contained
chemicals
of
higher
concern
to
human
health.
12
However,
the
listed
chemicals
represent
a
small
portion
of
those
that
are
regulated
or
are
of
potential
public
health
importance.
For
example,
there
are
over
7,000
lists
of
chemical
substances
and
classes
that
are
regulated
under
the
Toxic
Substances
Control
Act
and
the
Emergency
Planning
and
Community
Right­
to­
Know
Act.

For
those
individual
lists
that
we
reviewed,
the
portion
of
toxic
chemicals
measured
ranged
from
2
percent
of
chemicals
prioritized
for
safety
testing
(
based
on
EPA's
findings
that
the
chemicals
may
present
unreasonable
risks)
to
about
23
percent
of
chemicals
most
often
found
at
the
nation's
Superfund
sites
and
identified
as
posing
the
most
significant
threat
to
human
health.
See
table
1
for
each
of
the
lists
reviewed
and
the
extent
to
which
NHANES
or
the
NHEXAS
pilots
are
measuring
these
chemicals,
and
appendix
I
for
a
discussion
of
each
list
included
in
our
review.

10CDC
officials
indicated
that,
by
the
end
of
1999,
it
had
developed
laboratory
methods
to
measure
more
than
half
of
the
chemicals
under
the
agreement
with
NIEHS.

11We
excluded
NHATS
and
Human
Exposure
Initiative
chemical
lists
from
our
analysis.
NRC's
1991
review
of
the
NHATS
program
raised
questions
about
the
representativeness
of
the
results
and
the
methods
used
to
handle
the
tissue
specimens,
among
other
questions.
The
Human
Exposure
Initiative
measurements
were
not
available
at
the
time
of
our
review
and,
thus,
which
chemicals
had
been
or
are
currently
being
measured
was
not
known.

12We
selected
these
lists
based
on
input
from
program
officials
and
experts
at
EPA,
HHS,
the
Association
of
Public
Health
Laboratories,
and
the
Pew
Commission
on
Environmental
Health
and
our
assessment
that
the
criteria
for
listing
a
chemical
demonstrated
that
exposure
could
potentially
be
harmful
to
humans.
There
are
many
toxic
chemical
lists
maintained
by
different
programs
and
agencies
for
different
purposes
that
we
did
not
include
in
our
review
and,
as
such,
the
ones
we
reviewed
do
not
necessarily
individually
or
collectively
represent
the
chemicals
of
highest
concern
to
human
health.
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Table
1:
Extent
toWhich
Human
Exposure
Data
Are
Collected
for
Potentially
Harmful
Chemicals
Through
NHANES
or
the
NHEXAS
Pilot
Surveys
Note:
Our
analysis
was
based
on
human
exposure
data
collected
through
NHANES
or
the
NHEXAS
pilot
surveys
through
2000.

aThe
Report
on
Carcinogens
list
may
also
include
pharmaceutical
agents,
substances
of
primarily
occupational
concern,
and
banned
substances.
According
to
NIEHS
officials,
this
may
account
for
their
lower
inclusion
in
NHANES
or
the
NHEXAS
pilots.
NIEHS
and
NTP
officials
indicated
that,
in
addition
to
these
chemicals,
NTP
reports
results
of
its
chronic
bioassays
for
cancer
in
its
technical
report
series.
There
are
now
approximately
500
reports,
which
collectively
include
nearly
250
chemicals
found
to
cause
cancer
in
rodents.
Officials
indicated
that
another
useful
evaluation
would
assess
the
proportion
of
rodent
carcinogens
for
which
human
exposure
data
are
collected
and
that
NTP
is
planning
to
conduct
such
an
evaluation.

While
many
potentially
harmful
chemicals
in
these
lists
are
not
measured
in
the
population,
NHANES
or
the
NHEXAS
pilot
surveys
contain
a
greater
portion
of
chemicals
considered
of
higher
priority.
Two
toxic
chemical
lists
we
reviewed
 
one
ranking
chemicals
frequently
found
at
Superfund
sites
and
one
ranking
selected
chemicals
compiled
by
EPA
 
prioritized
chemicals
based
on
their
potential
to
harm
human
health.
We
examined
the
highest­
ranked
chemicals
on
these
lists
and
found
that
higher
proportions
of
these
chemicals
were
or
will
be
measured
compared
to
the
overall
list.
A
CDC
laboratory
official
also
indicated
CDC
was
in
the
process
of
Priority
chemicals
Chemicals
measured
or
being
measured
Description
of
list
Number
in
list
Number
Percent
Chemicals
found
most
often
at
the
national
Superfund
sites
and
of
most
potential
threat
to
human
health
275
62
23%

EPA's
list
of
toxics
of
concern
in
air
168
27
16
Chemicals
harmful
because
of
their
persistence
in
the
environment,
tendency
to
bioaccumulate
in
plant
or
animal
tissues,
and
toxicity
368
52
14
Pesticides
of
potential
concern
as
listed
by
EPA's
Office
of
Pesticide
Programs
and
the
U.
S.
Department
of
Agriculture's
Pesticide
Data
Program
243
32
13
Chemicals
that
are
reported
in
the
Toxic
Release
Inventory;
are
considered
toxic;
and
are
used,
manufactured,
treated,
transported,
or
released
into
the
environment
579
50
9
Chemicals
that
are
known
or
probable
carcinogens
as
listed
in
HHS'
Report
on
Carcinogensa
234
17
7
Chemicals
most
in
need
of
testing
under
the
Toxic
Substances
Control
Act
(
Master
Testing
list)
476
10
2
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developing
methods
to
measure
a
number
of
the
chemicals
on
these
lists
and
planned
to
measure
other
chemicals
in
future
efforts
if
they
have
adequate
resources
to
do
so.

°
Ranking
of
chemicals
frequently
found
at
Superfund
sites:
Developed
by
EPA
and
HHS'
Agency
for
Toxic
Substances
and
Disease
Registry
(
ATSDR),
which
conducts
public
health
assessments
or
other
health
investigations
for
populations
living
around
national
Superfund
sites,
this
list
ranks
substances
that
are
most
commonly
found
at
Superfund
sites
and
pose
the
most
significant
potential
threat
to
human
health
due
to
their
known
or
suspected
toxicity
and
potential
for
human
exposure.
Of
the
top
40
chemicals
on
this
list,
CDC
indicated
that
9
were
currently
being
measured
in
NHANES.
CDC
hopes
to
include
an
additional
30
of
the
top
40
in
future
efforts;
11
of
these
30
chemicals,
however,
were
included
in
the
NHEXAS
pilot
surveys.
°
Ranking
of
selected
toxic
chemicals
compiled
by
EPA:
These
rankings
are
based
on
a
chemical's
persistence,
tendency
to
accumulate
in
plants
and
animals,
and
toxicity.
CDC
indicated
4
of
the
top
22
chemicals
on
this
list
based
on
their
health
hazard13
were
currently
being
measured
in
NHANES.
CDC
hopes
to
include
the
remaining
18
in
future
efforts;
6
of
the
18
chemicals
were
included
in
the
NHEXAS
pilot
surveys.

Federal
Efforts
Are
Limited
for
Identifying
At­
Risk
Subpopulations
In
recent
years,
federal
agencies
have
been
charged
with
identifying
whether
certain
populations
 
including
minorities,
people
with
low
incomes,
and
children
 
disproportionately
face
greater
health
risks
because
they
have
greater
exposure
to
environmental
hazards.
14
Researchers
increasingly
recognize
that
the
scarcity
of
adequate
and
appropriate
data,
especially
for
exposures
and
related
health
effects,

13EPA's
prioritized
chemical
list
ranks
chemicals
based
on
the
length
of
time
to
break
down,
the
degree
to
which
they
accumulate
in
plants
and
animals,
and
their
toxicity.
Both
ecological
and
health
risk
scores
are
calculated.
We
used
only
the
health
risk
scores
in
our
analysis.

14Executive
Order
12898
requires
that
each
agency
identify
and
address
as
appropriate
disproportionately
high
and
adverse
human
health
or
environmental
effects
of
its
programs,
policies,
and
activities
on
minority
populations
and
low­
income
populations
in
the
United
States
and
its
territories
and
possessions.
Executive
Order
13045
established
similar
requirements
with
respect
to
children.
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hinders
efforts
to
more
systematically
identify
groups
that
may
be
at
risk.
15
Lacking
such
data,
past
efforts
to
identify
the
exposures
of
certain
demographic
groups
have
often
relied
on
measures
of
chemical
levels
in
the
surrounding
environment.
For
example,
some
studies
around
hazardous
waste
sites
and
industrial
plants
have
shown
that
minorities
and
low­
income
subpopulations
are
disproportionately
represented
within
the
geographic
area
around
the
sites.
Such
studies
are
limited
in
identifying
the
actual
health
risk
because
they
must
make
assumptions
about
how
these
substitute
measures,
such
as
how
close
one
lives
to
a
hazardous
waste
site,
relate
to
actual
exposures
experienced
by
people.

To
identify
groups
whose
exposure
is
disproportionately
greater
than
that
experienced
by
the
remainder
of
the
population
 
and
thereby
provide
more
definitive
assessments
of
whether
certain
groups
potentially
face
greater
health
risks
 
health
officials
and
researchers
might
measure
exposure
levels
for
(
1)
a
representative
sample
and
analyze
the
characteristics
of
subpopulations
with
the
highest
exposures
or
(
2)
a
population
thought
to
be
at
high
risk
and
compare
it
to
measurements
from
a
reference
population.
16
We
examined
the
extent
to
which
federal
survey
data
on
human
exposures
collected
to
date
could
be
used
to
assess
characteristics
of
those
groups
most
exposed.
We
also
examined
the
extent
to
which
human
exposure
data
was
collected
on
a
population
considered
to
be
at
higher
risk
 
specifically,
those
living
around
national
priority
hazardous
waste
sites.
In
each
effort,
the
information
collected
has
been
limited,
as
discussed
below.

Sampling
Not
Sufficient
to
Identify
Many
Highly
Exposed
Groups
Representative
sampling
is
required
to
identify
at­
risk
subpopulations
in
a
non­
biased
way
 
that
is,
without
presupposing
that
a
certain
group
is
at
higher
risk.
The
sample
must
also
be
large
enough
to
ensure
highly
exposed
15S.
Perlin,
K.
Sexton,
and
D.
Wong,
"
An
Examination
of
Race
and
Poverty
for
Populations
Living
Near
Industrial
Sources
of
Air
Pollution,"
Journal
of
Exposure
Analysis
and
Environmental
Epidemiology,

Vol.
9,
No.
1
(
1999),
pp.
29­
48.

16D.
Wagener,
D.
Williams,
and
P.
Wilson,
"
Equity
in
Environmental
Health:
Data
Collection
and
Interpretation
Issues,"
Toxicology
and
Industrial
Health,
Vol.
9,
No.
5
(
1993),
pp.
775­
95.
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subpopulations
can
be
objectively
identified.
17
For
nearly
all
chemicals
except
lead,
however,
past
federal
collection
of
human
exposure
data
in
NHANES
and
the
NHEXAS
pilot
surveys
has
been
insufficient
to
identify
whether
disproportionate
exposures
are
occurring
in
many
demographic
groups.
In
the
case
of
NHANES,
the
sample
is
generally
drawn
to
reflect
the
national
population
as
a
whole.
18
Consequently,
the
sample
of
the
group
of
interest
may
be
too
small
to
draw
meaningful
conclusions
about
characteristics,
such
as
exposures,
of
the
group.
In
the
past,
most
NHANES
exposure
measurements
were
conducted
among
non­
randomly­
selected
samples
and
from
only
a
portion
of
the
surveyed
participants,
thus
limiting
the
ability
to
identify
highly
exposed
groups.
Lead
was
an
exception.
Data
for
blood
lead
levels
in
children
have
been
the
most
comprehensively
collected,
and
certain
characteristics
have
been
clearly
associated
with
a
higher
prevalence
of
blood
lead
levels.
EPA
has
concluded
that
the
evidence
is
unambiguous:
children
of
color
have
a
higher
prevalence
of
elevated
blood
lead
levels
than
white
children
do,
and
children
in
lowerincome
families
have
a
higher
prevalence
than
children
in
higher
income
families.
See
table
2
for
the
most
recent
NHANES
analysis.

17The
feasibility
of
using
a
representative
survey
to
identify
at­
risk
subpopulations
based
on
individual
characteristics
(
such
as
age,
race,
or
income
level)
or
location
(
such
as
a
city,
county,
or
state)
depends
on
sample
design
and
size
 
that
is,
on
how
the
participants
are
selected
and
how
many
participants
are
included.
Generally,
the
lower
the
percentage
of
the
population
in
question
in
the
sample,
the
less
the
data
can
be
used
to
develop
precise
estimates
of
exposure
or
to
distinguish
exposure
levels
between
subgroups.

18Certain
groups
may
be
included
at
a
higher
rate
or
oversampled
to
ensure
a
greater
level
of
accuracy.
For
example,
between
1988
and
1994,
children
ages
2
months
through
5
years
surveyed
in
NHANES
were
oversampled.
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Table
2:
Prevalence
of
Elevated
Blood
Lead
Levels
in
Children
Ages
1
Through
5,
by
Selected
Demographic
Characteristics
(
NHANES,
1991
Through
1994)

Source:
CDC,
"
Update:
Blood
Lead
Levels
 
United
States,
1991­
1994,"
Morbidity
and
Mortality
Weekly
Report,
Vol.
46,
No.
7
(
1997),
pp.
141­
5.

CDC
officials
told
us
that
representative
data,
such
as
that
collected
for
lead,
would
be
collected
for
a
larger
number
of
chemicals
starting
in
1999.
However,
CDC
plans
indicated
that
for
most
chemicals
monitored,
only
a
portion
of
NHANES
survey
participants
 
generally
one­
third
or
fewer,
depending
on
the
type
of
chemical
 
would
be
tested.
For
some
chemicals,
only
certain
groups
thought
to
be
at
higher
risk
may
be
tested.
For
example,
NHANES
will
include
measurement
of
certain
persistent
pesticides
known
as
organochlorines
in
one­
third
of
the
survey
participants
ages
12
through
19.
Children
under
12
will
not
be
assessed.
19
CDC
officials
indicated
that
people
over
19
may
be
assessed
if
adequate
resources
are
available
to
do
so.
Although
most
organochlorines
are
banned
in
the
United
States,
some
are
still
used
in
home
and
garden
products,
such
as
products
for
treating
lice
and
controlling
agricultural
and
structural
pests
and
flame
Characteristic
of
children
in
sample
Percentage
with
elevated
blood
lead
levels
Race/
ethnicity
Black,
non­
Hispanic
11.2%

Mexican­
American
4.0
White,
non­
Hispanic
2.3
Income
level
Low
8.0
Middle
1.9
High
1.0
Age
group
1
through
2
5.9
3
through
5
3.5
Total
ages
1
through
5
4.4%

19According
to
CDC
officials,
children
under
12
will
not
be
assessed
because
the
volume
of
tissue
samples
needed
to
perform
the
measurement
will
not
be
available.
Other
measurements
 
such
as
those
for
lead,
mercury,
and
cotinine
(
a
metabolite
of
nicotine
illustrating
exposure
to
cigarette
smoke)
 
will
be
performed
for
many
in
this
age
group.
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retardants
used
in
synthetic
fabrics.
20
NHANES
data
from
a
one­
third
subsample
will
be
useful
for
establishing
reference
ranges
within
the
population
and
illuminating
exposure
levels
nationally;
they
will
also
be
useful
for
identifying
exposures
of
broad
demographic
groups,
such
as
males
and
females.
But
these
data
are
not
enough
to
enable
researchers
to
assess
exposure
levels
of
or
characterize
many
potentially
at­
risk
groups,
such
as
the
exposures
of
inner­
city
children
in
low­
income
families.
21
According
to
a
CDC
laboratory
official,
targeted
studies
should
be
considered
for
groups
that
represent
a
small
portion
of
the
population.

Similarly,
the
NHEXAS
pilot
surveys
included
representative
samples
of
participants
in
the
three
geographic
locations
covered.
However,
because
of
the
smaller
sample
sizes,
the
work
to
date
has
also
been
too
limited
for
20According
to
CDC
laboratory
officials,
other
NHANES
exposure
measurements
planned
for
1999
and
2000
for
a
subsample
of
participants
includes
volatile
organic
compounds,
mercury,
nonpersistent
pesticides,
phthalates,
and
trace
metals.
Air
toxic
exposures
to
selected
volatile
organic
compounds
will
be
measured
in
personal
measurements
 
such
as
chemical
levels
in
the
air,
measured
through
badges,
and
chemicals
in
water
samples
 
and
in
blood
samples
from
a
subsample
of
people
ages
20
through
59.
Mercury
will
be
measured
in
the
hair
and
blood
of
participants
ages
1
through
5
and
women
ages
16
through
49.
Nonpersistent
pesticides
or
their
metabolites
are
planned
for
measurement
in
one­
half
of
participants
ages
6
through
11
and
one­
third
of
participants
ages
12
and
over.
Surveys
and
focused
research
indicate
that
household
use
of
certain
pesticides
may
be
extensive,
but
little
information
is
available
concerning
residential
or
household
exposures
among
the
general
population.
Phthalates
are
planned
for
measurement
in
one­
third
of
the
participant
ages
6
and
older.
Seventeen
trace
metals
will
be
measured
in
one­
third
of
participants
ages
6
and
older.
Trace
metals
such
as
barium
and
beryllium
have
been
associated
with
adverse
health
effects
in
occupational
or
laboratory
studies
but
have
not
been
monitored
in
the
general
population.

21The
current
design
of
NHANES
samples
allows
several
years
of
data
to
be
combined.
If
exposure
for
chemicals
is
measured
consistently
over
several
years,
then
assessing
risk
factors
may
be
increasingly
possible
over
time.
CDC
officials
indicated
that
for
any
annual
NHANES
full
sample,
a
limited
number
of
estimates
for
broad
population
subgroups
can
be
developed.
More
detailed
measures
for
smaller
subgroups
(
for
example,
analyses
by
age,
gender,
and
race
and
ethnicity)
will
require
more
years
of
data,
generally
3
through
6
years
 
and
even
longer
if
a
subsample
is
used
 
of
data
collected
for
all
participants.
Based
on
an
annual
sample
of
one­
third
of
the
participants,
CDC
indicated
that
estimates
may
be
possible
for
very
broad
subgroups,
such
as
males
or
females;
participants
ages
6
through
19
or
over
20;
or
a
few
major
race
and
ethnicity
groups,
depending
on
the
prevalence
of
the
condition
examined.
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Needs
much
analysis
of
at­
risk
populations.
22
The
pilot
surveys
included
biological
measurements
for
about
200
people
in
six
Midwestern
states,
about
180
people
in
Arizona,
23
and
about
80
people
in
Baltimore.

Federal
Efforts
to
Identify
Communities
of
Concern
Valuable,
but
Human
Exposure
Data
Are
Limited
A
second
method
to
identify
a
subpopulation
disproportionately
at
risk
of
adverse
health
effects
is
to
compare
exposure
levels
for
a
group
thought
to
be
at
high
risk
with
baseline
measurements
from
a
reference
population.
24
This
method
can
be
used
to
determine,
for
example,
the
extent
to
which
people
in
a
neighborhood,
community,
or
geographic
location
are
exposed
relative
to
others.
In
cases
where
exposure
levels
have
been
identified
as
high
compared
to
reference
populations
but
potential
health
effects
associated
with
those
levels
have
not
been
researched,
public
health
actions
can
help
prevent
further
or
increasing
exposures,
and
these
groups
can
be
assessed
for
any
subsequent
health
outcomes.

22One
assessment
of
the
data
from
Midwestern
states
provided
some
indication
of
potential
differences
in
personal
exposures
between
age
groups,
races,
income
segments,
and
house
construction
dates.
Researchers
cautioned
that
the
data
for
some
categories
examined
were
small.
This
assessment
did
not
report
on
exposure
measurements
from
biological
sampling
in
this
survey.
(
See
E.
D.
Pellizzari,
R.
L.
Perritt,
and
C.
A.
Clayton,
"
National
Human
Exposure
Assessment
Survey:
Exploratory
Survey
of
Exposure
Among
Population
Subgroups
in
EPA
Region
V,"
Journal
of
Exposure
Analysis
and
Environmental
Epidemiology,

Vol.
9
(
1999),
pp.
49­
55.

23These
participants
provided
biological
samples,
such
as
blood
and
urine.
Larger
participant
groups
in
the
study
areas
provided
environmental
and
food
monitoring
samples
and
responded
to
questionnaires.
This
excludes
a
related
but
separate
study
done
in
Minnesota
reviewing
pesticide
exposures
that
was
not
one
of
the
three
formal
pilot
surveys.

24Determining
the
distribution
of
chemical
exposure
among
a
non­
occupationally­
exposed
population
establishes
a
"
reference
range"
that
shows
what
can
be
considered
background
exposure
and
what
can
be
considered
high.
With
reference
range
information,
officials
concerned
about
exposures
of
groups
can
compare
the
groups'
exposures
to
those
of
the
general
population
and
determine
whether
public
health
action
is
warranted
to
prevent
or
reduce
high
levels
of
exposure.
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One
federal
effort,
conducted
by
ATSDR,
analyzes
risks
faced
by
communities
near
hazardous
waste
sites.
ATSDR
estimates
that
12.5
million
people
live
within
1
mile
of
the
nation's
1,300
Superfund
sites.
The
agency
can
collect
biological
samples
through
exposure
investigations
as
part
of
the
public
health
assessment
process
or
in
response
to
requests
from
the
public.
25
ATSDR
officials
said
that
human
exposure
data
collected
at
Superfund
sites
have
been
useful
in
deciding
on
actions
such
as
stopping
or
reducing
exposures,
relocating
residents,
referring
residents
for
medical
follow­
up,
reducing
community
anxiety,
influencing
priorities
on
sitespecific
clean­
up,
making
referrals
to
researchers
for
assessing
health
links,
and
educating
community
and
other
health
providers.
As
evidence,
they
pointed
to
the
conclusions
of
an
expert
review
panel,
which
stated
in
March
1997
that
human
exposure
data
were
as
important
to
exposure
investigations
and
public
health
assessments
as
environmental
monitoring
results
at
the
sites
of
concern.
26
However,
the
number
of
investigations
that
included
human
exposure
data
has
been
limited.
Between
1995
and
July
1999,
ATSDR
had
gathered
biological
samples
at
only
about
47
of
the
more
than
1,300
Superfund
sites.
At
least
34
of
these
investigations
detected
contaminants
in
people
and
16
found
elevated
levels.

Other
federally
conducted
efforts
designed
to
monitor
or
collect
data
on
the
exposures
of
populations
within
selected
communities
or
geographic
regions
have
also
been
infrequent.
27
One
such
regional­
scale
effort
under
way
is
collecting
data
on
exposures
within
selected
communities
along
the
border
between
Texas
and
Mexico.
Officials
from
Mexico
and
federal
and
state
agencies
in
the
United
States
are
comparing
exposures
of
people
in
25ATSDR
conducts
exposure
investigations
when
(
1)
people
have
likely
been
exposed
to
a
contaminant,
(
2)
more
information
is
needed
on
the
exposure,
(
3)
an
exposure
investigation
will
provide
that
information,
and
(
4)
that
investigation
will
affect
public
health
decisions.

26In
its
report,
panel
members
suggested
many
improvements
to
ATSDR's
exposure
investigations,
including
creating
a
technical
planning
group
to
review
emerging
and
innovative
technologies
and
establishing
a
national
clearinghouse
of
collected
data.
ATSDR
officials
indicated
that
they
had
not
been
able
to
act
on
some
of
the
panel's
suggestions
because
of
limited
staff
and
resources
and
other
barriers
to
collecting
data,
such
as
the
lack
of
laboratory
methods
for
testing
chemicals
of
interest.
ATSDR
has
nine
staff
to
conduct
exposure
assessments
for
sites
across
the
nation
and
can
only
respond
to
requests
from
communities
or
state
or
local
officials
for
assistance
rather
than
conducting
such
assessments
as
part
of
every
new
investigation.

27Federal
agencies
also
might
fund
academic
research
that
is
designed
to
identify
communities
of
concern.
Assessing
the
extent
that
federally
supported
academic
research
included
or
focused
on
human
exposure
data
to
identify
at­
risk
population
was
beyond
the
scope
of
our
review.
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the
border
area
with
those
in
areas
away
from
the
border.
Another
study
examined
the
exposures
of
people
along
the
Arizona
border
compared
to
the
exposures
of
people
elsewhere
in
the
state.
This
study
collected
environmental
samples
for
pesticides,
metals,
and
volatile
organic
chemicals.
Blood
and
urine
samples
were
also
tested
to
relate
the
environmental
measurements
to
the
measurements
in
human
tissues
for
these
chemicals.

State
Officials
Value
Human
Exposure
Data
for
Studies
and
Investigations
but
Do
Not
Often
Include
Them
Most
state
officials
who
we
surveyed
highly
valued
human
exposure
data.
However,
most
could
not
include
it
in
their
exposure­
related
health
studies,
investigations
of
concerns
such
as
disease
clusters,
or
surveillance
efforts.
Almost
half
of
the
officials
responding
to
our
survey
estimated
that
they
had
participated
in
10
or
more
exposure­
related
studies
or
investigations
since
1996,
with
about
16
percent
estimating
they
participated
in
50
or
more.
However,
about
half
of
officials
indicated
they
could
seldom
if
ever
collect
exposure
data
through
human
samples
in
their
efforts.
When
data
were
developed,
officials
listed
five
main
uses:
(
1)
environmental
health
epidemiologic
studies,
(
2)
surveillance
of
diseases
or
conditions
with
suspected
environmental
causes,
(
3)
investigations
of
citizen
concerns,
(
4)
planned
or
accidental
chemical
releases,
and
(
5)
disease
clusters
(
see
table
3).
28
State
officials
we
spoke
with
noted
that
human
exposure
data
are
often
the
most
valid
and
persuasive
evidence
available
to
demonstrate
whether,
and
to
what
extent,
exposure
has
occurred
or
changed
over
time.
In
highly
charged
situations,
where
community
trust
has
eroded,
such
data
may
be
the
only
evidence
acceptable
to
area
residents.

28Since
most
states
conduct
surveillance
for
lead
exposure,
we
asked
officials
to
not
include
these
efforts
in
their
responses.
See
app.
III
for
a
copy
of
our
survey.
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Table
3:
Examples
of
How
State
Officials
Use
Human
Exposure
Data
While
mercury,
arsenic,
and
pesticides
were
most
often
reported
as
being
studied
in
human
samples,
some
state
officials
reported
using
human
exposure
data
for
chemicals
that
CDC
has
since
1991
developed
methods
to
measure.
For
example,
about
15
percent
of
officials
conducted
studies
of
human
exposure
to
volatile
organic
compounds,
and
almost
30
percent
reported
studies
of
exposure
to
PCBs
using
data
from
tissue
analysis.

Regardless
of
whether
state
officials
had
collected
or
used
human
exposure
data
in
the
past
4
years,
about
90
percent
of
those
officials
responding
to
our
survey
said
human
exposure
data
from
tissue
samples
was
extremely
or
very
important
for
addressing
environmental
health
concerns.
Despite
the
perceived
value
of
such
data,
almost
two­
thirds
of
officials
said
they
could
include
human
exposure
data
in
fewer
than
half
of
the
exposure­
related
studies,
investigations,
and
surveillance
efforts
where
Purpose
Example
Environmental
health
epidemiologic
studies
Using
blood
and
urine
samples
from
people
who
ate
sport
fish
and
were
concerned
about
undue
exposure
to
dioxins,
pesticides,
and
other
chemicals,
health
officials
determined
these
people
had
exposure
to
some
chemicals
from
2
to
10
times
higher
than
levels
in
a
reference
population.
Based
on
these
results,
officials
will
focus
a
larger
health
effects
study
on
exposure
to
those
chemicals.

Surveillance
of
diseases
or
conditions
with
suspected
environmental
causes
Virtually
all
states
collect
information
on
blood
lead
levels
in
children
to
monitor
and
prevent
lead
poisoning.
Some
also
monitor
exposure
to
pesticides
and
other
chemicals
such
as
mercury
and
arsenic.

Investigation
of
citizen
concerns
Health
officials
used
human
tissue
measurements
and
citizens'
reports
of
illnesses
to
demonstrate
that
the
combined
effect
of
chemicals
released
into
the
environment
posed
a
health
hazard
severe
enough
to
warrant
evacuating
nearby
residents.
State
and
federal
officials
subsequently
closed
a
manufacturing
plant
because
of
the
harmful
health
effects
of
its
chemical
releases.

Investigation
of
planned
or
accidental
chemical
releases
Officials
in
nine
states
asked
CDC
to
test
tissue
samples
from
almost
17,000
individuals
thought
to
have
been
exposed
to
methyl
parathion,
a
deadly
pesticide.
CDC's
ability
to
measure
the
pesticide
in
human
tissue
and
compare
exposures
across
states
was
critical
to
identifying
individuals
with
high
exposures
and
houses
most
in
need
of
clean­
up.
Because
relocating
residents
and
removing
the
pesticide
from
homes
cost
up
to
$
250,000
per
household,
the
exposure
data
helped
officials
avoid
spending
limited
funds
on
houses
that
did
not
pose
a
health
risk
to
the
people
living
in
them.
One
state
official
said
the
exposure
results
reduced
the
number
of
houses
needing
pesticide
removal
from
hundreds
to
fewer
than
10.

Investigation
of
disease
clusters
State
health
officials
reviewed
data
on
individual
cases
of
cancer
in
one
community
and
for
the
entire
state.
When
available
data
on
known
risk
factors
did
not
account
for
the
increased
incidence
of
breast
cancer,
officials
began
a
more
detailed
study
that
included
human
tissue
analysis.
Blood
samples
were
obtained
from
women
before
and
after
treatment
began
and
from
women
in
a
control
group.
Results
will
be
compared
to
reference
range
data
developed
by
CDC.
One
goal
of
such
studies
is
to
help
identify
environmental
factors
that
contribute
to
breast
cancer
risk.
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they
considered
it
important.
More
than
one­
third
said
they
seldom
could
include
such
data.

Several
state
health
and
laboratory
officials
whom
we
interviewed
expressed
frustration
at
the
missed
opportunities
for
collecting
biological
samples
as
part
of
their
studies
and
investigations
for
reasons
such
as
limited
laboratory
capacity.
For
example,
health
officials
in
one
state
could
not
examine
the
role
played
by
methyl
t­
butyl
ether
(
MTBE)
 
an
additive
designed
to
promote
more
efficient
burning
of
gasoline
 
in
a
major
respiratory
disease
outbreak
because
state
staff
lacked
the
expertise
and
CDC
staff
lacked
the
time
to
conduct
the
needed
tests.
In
1995,
after
MTBE
was
added
to
gasoline
and
thousands
of
citizens
reported
becoming
ill,
state
officials
wanted
to
measure
MTBE
or
its
by­
products
in
blood
from
samples
of
individuals
with
and
without
symptoms
to
determine
whether
MTBE
exposure
might
be
the
cause
or
a
contributing
factor.
Objective
measures
of
individual
exposure
might
have
allowed
public
health
officials
to
conclusively
demonstrate
or
rule
out
a
link
between
the
outbreak
and
exposure,
something
that
was
not
possible
with
environmental
data
and
epidemiologic
surveys.
The
chemicals
officials
most
often
cited
as
wanting
to
study
using
human
exposure
data
but
could
not
were
pesticides
and
volatile
organic
compounds.

Significant
Information
and
Infrastructure
Gaps
Point
to
Need
for
Strategic
Planning
and
Coordination
As
part
of
our
survey
and
interviews,
we
asked
public
health
experts
and
state
and
federal
officials
to
identify
barriers
they
considered
significant
to
their
efforts
to
collect
and
use
human
exposure
data.
Officials
cited
two
primary
barriers:
the
lack
of
laboratory
capacity
or
methods
to
analyze
tissue
samples
and
the
lack
of
information
to
help
set
exposure
test
results
in
context.
Addressing
these
barriers
takes
time
and
resources.
In
that
regard,
we
identified
a
third
barrier
to
more
effective
use
of
existing
resources:
HHS
and
EPA
lack
a
long­
term
strategic
plan
to
address
infrastructure
and
science
barriers,
coordinate
efforts
to
meet
federal
and
state
needs,
and
address
the
many
questions
about
how
to
set
priorities
given
their
limited
resources.
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Laboratory
Capacity
and
Methods
to
Measure
More
Chemicals
Needed
State
officials
frequently
said
insufficient
laboratory
capacity
in
their
states
and
at
the
federal
level
hindered
their
ability
to
obtain
human
exposure
data
in
cases
where
they
thought
such
data
were
important.
Over
half
of
the
officials
said
their
states
lacked
sufficient
numbers
of
trained
laboratory
staff,
sufficient
laboratory
capacity
to
analyze
samples,
or
sufficient
laboratory
equipment.
Many
officials
attribute
such
capacity
limitations
to
funding
constraints
because
tissue
analyses
can
be
timeconsuming
and
expensive
to
perform.
For
example,
according
to
a
CDC
official,
each
test
to
measure
dioxins
in
a
sample
requires
(
1)
a
laboratory
free
from
chemicals
that
could
compromise
test
results,
(
2)
specialized
equipment
that
costs
about
$
500,000,
and
(
3)
highly
trained
and
experienced
staff
to
complete.
Officials
of
a
professional
organization
representing
public
health
laboratories
told
us
that,
although
many
state
laboratories
perceive
they
have
a
role
in
conducting
tests
to
detect
toxic
substances
in
humans,
very
few
currently
have
such
capacity.
29
State
and
federal
officials
we
interviewed
told
us
that
because
few
state
laboratories
have
the
necessary
equipment
and
expertise,
they
often
rely
on
CDC's
environmental
health
laboratory
staff
to
analyze
tissue
samples.
Given
the
specialized
laboratory
requirements,
CDC's
environmental
health
laboratory
is
generally
considered
the
best­
suited
to
analyze
tissue
samples
for
a
range
of
chemicals
and
has,
in
fact,
developed
many
of
the
methods
to
do
so,
according
to
federal
and
state
officials.
CDC's
laboratory
performs
measurements
for
most
federal
and
many
state
efforts
to
gather
human
exposure
data.
Many
officials
said
CDC's
laboratory
capacity
is
essential
to
their
efforts
and
needs
to
expand
to
meet
growing
needs.
A
few
state
officials
said
CDC's
laboratory
consistently
returned
test
results
when
people's
lives
were
at
risk
but
was
less
able
to
help
states
assess
health
risks
more
generally.
An
official
in
one
state
said
that,
while
CDC's
assistance
is
invaluable,
the
state's
laboratory
capacity
allowed
public
health
officials
to
obtain
human
exposure
data
and
investigate
citizen's
concerns
more
frequently
than
they
could
if
they
had
to
rely
soley
on
CDC's
laboratory
capacity.

29This
organization
actively
supports
expanding
state
and
local
laboratory
capacity
to
participate
in
a
human
biomonitoring
program
to
provide
human
exposure
data
that
would
enhance
the
effectiveness
of
environmental
policy
and
regulatory
decisions.
In
addition,
this
group
helped
states
apply
for
the
four
grants
CDC
offered
to
increase
state
and
local
laboratory
capacity
to
detect
in
human
fluids
and
tissues
chemicals
that
could
be
used
in
a
terrorist
attack.
Illustrating
their
interest
in
developing
such
laboratory
capacity,
31
state
and
2
local
health
departments
applied
for
the
four
grants.
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Another
significant
issue
is
the
lack
of
analytical
laboratory
methods
to
measure
chemicals
of
concern.
Despite
advances
over
the
past
2
decades
in
analytic
chemistry
and
molecular
biology,
laboratory
methods
have
not
been
developed
to
measure
about
88
percent
of
the
1,456
chemicals
in
our
review,
according
to
information
provided
by
CDC
and
EPA
officials.
Although
laboratory
staff
at
CDC
have
quickly
applied
scientific
and
technological
advances
to
develop
new
and
more
efficient
laboratory
methods,
they
are
concerned
about
the
lack
of
methods
to
test
a
single
human
sample
for
several
related
toxics.
For
example,
a
method
exists
to
measure
arsenic
in
blood
but
not
to
measure
arsenic
and
other
heavy
metals
at
the
same
time.
Such
methods
make
more
efficient
use
of
the
samples
that
are
gathered
and
greatly
reduce
the
time
and
money
needed
to
test
large
numbers
of
samples.
While
CDC's
laboratory
continuously
develops
new
chemical
testing
methods,
current
resources
limit
the
number
to
about
10
annually.

Even
when
analytical
methods
exist,
efforts
to
gather
human
exposure
data
are
sometimes
limited
by
problems
with
the
methods
used
to
gather
the
samples.
This
is
especially
true
for
young
children,
a
group
thought
to
be
particularly
susceptible
to
harmful
effects
from
exposure.
In
some
cases,
existing
laboratory
methods
require
sample
volumes
that
can
only
be
obtained
through
invasive
techniques.
That
is,
blood
samples
must
be
obtained
by
puncturing
a
vein
rather
than
by
pricking
a
finger.
Many
people
will
not
allow
their
children
to
participate
in
studies
that
require
such
techniques.
Similarly,
urine
samples
can
be
difficult
to
obtain
from
children
who
wear
diapers.
For
example,
substances
in
the
diapers
can
compromise
test
results.

Information
Needed
to
Interpret
Human
Exposure
Measurements
To
help
interpret
the
results
of
laboratory
analysis
and
determine
what
actions,
if
any,
are
needed
to
protect
the
public's
health,
state
and
federal
officials
cited
the
need
for
two
types
of
context­
setting
data:
comparative
(
or
reference
range)
information
that
shows
exposure
levels
among
the
general
population
and
research
that
links
exposure
to
adverse
health
effects.
At
the
state
level,
where
many
of
the
specific
actions
regarding
atrisk
situations
are
taken,
almost
three­
fourths
of
responding
officials
cited
the
lack
of
such
information
as
a
problem.

State
officials
said
that
reference
range
data,
when
available,
allowed
them
to
determine
whether
exposures
are
sufficiently
high
to
merit
action
to
reduce
or
prevent
further
exposure.
For
example,
in
one
state,
public
health
officials,
with
help
from
CDC,
responded
to
citizens'
reports
of
foul
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odors
from
leaking
tanks
at
a
waste
cleanup
site
by
gathering
and
analyzing
blood
samples
from
those
living
nearby.
CDC's
analysis
of
the
blood
samples
showed
that
residents
near
the
site
had
exposure
levels
at
the
high
end
of
a
CDC­
developed
reference
range.
State
and
federal
officials
ordered
the
contractor
to
move
the
cleanup
operations
to
another
location.
Over
60
percent
of
state
officials
responding
to
our
survey
said
the
lack
of
reference
range
data
prevented
them
from
using
human
exposure
data
in
their
work.
State
officials
said
the
problem
for
research
about
adverse
health
effects
was
similar.
Much
of
the
data
linking
exposure
to
health
effects
concerns
high­
level
occupational
exposures
or
higher
doses
administered
to
laboratory
animals.
Consequently,
translating
the
results
of
such
research
to
lower­
level
exposures
of
people
and
determining
how
best
to
advise
people
about
potential
effects
is
problematic.

Federal
health
officials
and
researchers
also
cited
a
need
for
both
types
of
information
in
their
investigations,
particularly
for
federally
supported
work
in
specific
geographic
areas.
ATSDR
officials
said
the
lack
of
reference
ranges
was
a
particular
reason
they
could
not
generate
human
exposure
data
more
often
in
public
health
assessments
and
exposure
investigations.
When
data
allow
officials
to
put
exposure
into
context,
concerns
can
be
investigated
and
addressed.
For
example,
in
one
community,
where
citizens
were
concerned
about
exposure
to
dioxins
from
nearby
chemical
manufacturing
plants,
ATSDR
officials
had
CDC's
laboratory
analyze
blood
samples
and
found
that
some
residents
had
levels
of
several
dioxins
above
the
highest
levels
in
a
CDC­
ATSDR­
developed
reference
range.
In
response,
ATSDR
helped
residents
obtain
assistance
from
medical
professionals
expert
in
dioxins
and,
working
with
state
and
federal
environmental
agencies,
began
environmental
testing
to
locate
the
exposure
source.

Stronger
Interagency
Efforts
Needed
for
Strategic
Planning
and
Coordination
The
barriers
outlined
above
present
daunting
challenges
to
state
and
federal
agencies.
The
number
of
chemicals
that
remain
to
be
investigated
and
the
kinds
of
information
needed
are
substantial,
the
research
is
often
expensive,
and
progress
is
often
slow.
At
the
same
time,
the
level
of
resources
available
for
dealing
with
the
issue
is
limited,
and
responsibilities
are
fragmented
among
many
state
and
federal
agencies.
Many
studies
have
pointed
to
the
need
for
better
coordination.
While
HHS
and
EPA
efforts
have
been
coordinated
through,
for
example,
participation
on
advisory
committees
and
the
use
of
CDC's
laboratory
for
performing
the
actual
measurements,
such
coordination
falls
short
of
what
is
needed
for
longterm
planning.
This
need
is
illustrated
by
the
growing
convergence
of
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interest
in
the
planned
expansions
of
NHANES
and
NHEXAS.
To
ensure
as
much
progress
as
possible
with
available
resources,
HHS
and
EPA
need
a
strategic
planning
effort
that
reflects
a
clear
set
of
priorities,
a
framework
for
coordinating
data
collection
and
reporting
efforts,
and
a
tie
to
performance
goals.

Agreement
About
Need
for
Better
Planning
and
Coordination
of
Efforts
Is
Widespread
In
1991,
NRC
reported
that
"
although
a
successful
monitoring
program
must
be
highly
relevant
to
regulatory
needs,
it
could
and
should
serve
a
wide
range
of
client
programs
and
must
not
be
dominated
by
any
one
of
them."
NRC
reported
that
the
approaches
of
EPA,
CDC,
and
ATSDR
are
each
important
in
the
identification
and
control
of
environmental
hazards
to
human
health
and
that
coordination
among
the
programs
would
enhance
federal
monitoring
efforts
and
benefit
researchers,
health
professionals,
and
the
public.
30
Officials
and
experts
agree
that
interagency
interaction
is
needed
to
take
advantage
of
all
approaches
and
information
available
to
develop
the
most
cost­
effective,
least
burdensome
approach
for
collecting
needed
exposure
data.
Towards
this
end,
HHS
agencies
and
EPA
have
at
various
times
attempted
to
collaborate
in
their
respective
exposure
monitoring
efforts.
For
example,
EPA
solicited
broad
interagency
input
into
the
design
of
NHEXAS
and
established
interagency
agreements
with
CDC
and
others
to
assist
in
performing
laboratory
measurements,
quality
control,
and
other
support
functions.
Also
through
interagency
agreements,
CDC
has
broadened
the
exposure
monitoring
component
of
NHANES
to
incorporate
the
needs
of
EPA
researchers.

30While
NRC
found
EPA
in
the
best
position
to
house
a
human
exposure
monitoring
program,
it
also
found
that
the
ambivalence
within
EPA
about
the
National
Human
Monitoring
program's
future
indicated
that
the
match
of
program
goals,
potential
benefits,
and
EPA
mandates
was
not
perfect.
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Outside
reviews
and
involved
researchers
and
officials
indicate
that
even
with
recent
efforts,
coordination
has
fallen
short
in
ensuring
adequate
interaction
and
linkages
between
agencies.
For
example,
EPA's
scientific
advisers
reviewed
the
NHEXAS
pilot
surveys
and
concluded
that,
while
NHEXAS
was
an
excellent
project
and
highly
relevant
for
providing
needed
information,
a
strategic
plan
was
needed
for
follow­
up
studies.
They
also
urged
that
EPA
link
NHEXAS
exposure
data
with
biological
data
from
NHANES,
where
possible,
and
develop
a
more
collaborative
process
for
gathering
input
for
chemical
selection.
Attendees
at
a
September
1999
NIEHS
conference
on
the
Role
of
Human
Exposure
Assessment
in
the
Prevention
of
Environmental
Disease
also
called
for
a
coordinated
interagency
effort
in
assessing
human
exposure.
31
One
theme
and
recommendation
from
the
discussions
was
the
need
to
bridge
scientific
disciplines
and
agency
missions
to
address
knowledge
gaps
in
assessing
human
exposure.

State
officials
and
others
have
also
indicated
that
better
linkages
and
partnering
are
needed
between
federal,
state,
and
local
agencies.
For
example,
an
official
of
the
Association
of
Public
Health
Laboratories
told
us
that
one
way
to
improve
states'
involvement
in
a
national
exposure
monitoring
program
would
be
to
further
their
capability
to
assess
levels
of
toxic
chemicals
in
their
own
populations
relative
to
national
levels.
This
would
require,
in
this
official's
view,
the
transfer
of
new
monitoring
technology
to
state
public
health
laboratories,
along
with
the
resources
necessary
to
support
that
technology.
Improved
capacity
at
the
state
level
would
allow
federal
laboratories
to
concentrate
on
developing
more
and
faster
analytical
methods
for
measuring
chemicals
in
tissues
and
on
responding
to
crisis
situations.
Other
experts
have
also
called
for
better
linkages
between
federal
efforts
and
communities
and
community
concerns.
For
example,
the
NHEXAS
reviewers
recommended
that
EPA
improve
communication
between
NHEXAS
investigators
and
state
and
local
health
officials.
Another
theme
of
the
conference
on
human
exposure
assessment
was
that
efforts
to
assess
human
exposure
be
in
line
with
public
health
goals
and
community
concerns.

31The
NIEHS­
supported
conference
addressed
many
opportunities
and
challenges
in
exposure
assessment
research,
including
exposure­
analysis
methodology,
exposure­
disease
relationships,
regulatory
and
legislative
issues,
gene­
environment
interactions,
disease
prevention
and
intervention,
and
some
current
federal
initiatives
related
to
exposure
assessment.
One
area
of
discussion
was
the
need
for
and
limitations
of
biological
measures
of
exposure.
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Individual
Priorities
Contribute
to
Difficulties
in
Coordinating
Efforts
The
challenges
federal
and
state
agencies
face
in
setting
priorities
for
which
chemicals
to
assess
in
their
individual
programs
likely
contribute
to
the
difficulties
they
have
in
collaborating
with
one
another.
The
expense
of
conducting
exposure
measurements
in
ongoing
surveys
 
especially
for
the
number
of
samples
required
to
establish
national
or
regional
trends
and
levels
 
necessitates
that
priorities
be
set.
However,
agreeing
on
priorities
 
or
even
agreeing
on
the
process
for
setting
priorities
 
is
challenging
and
resource­
intensive.
For
example,
to
identify
chemicals
to
measure
in
NHEXAS,
EPA
undertook
an
extensive
selection
process,
soliciting
input
from
regional
and
program
offices.
32
EPA's
scientific
advisers,
while
supportive
of
the
program,
cited
the
criteria
for
selecting
target
chemicals
as
a
weakness.
NHANES
is
even
less
formal
in
this
regard,
with
no
documented
priority­
setting
process
for
chemicals
to
be
measured.
Chemicals
measured
are
largely
determined
by
CDC's
laboratory
scientists
based
on
such
factors
as
the
availability
of
analytical
methods
for
measuring
the
chemical
and
the
laboratory's
capacity
to
perform
the
measurements.
33
According
to
a
CDC
official,
CDC's
limited
staff
and
laboratory
resources
cannot
develop
the
administrative
infrastructure
to
establish
a
scientific
review
process
for
selecting
priority
chemicals.

Another
challenge
in
setting
priorities,
according
to
some
officials,
is
the
appropriate
balance
between
gathering
exposure
information
on
chemicals
about
which
little
is
known
and
gathering
information
on
those
already
considered
to
be
toxic.
NHANES
and
NHEXAS,
for
example,
focus
largely
on
chemicals
that
are
considered
to
be
toxic
at
some
level.
By
contrast,
the
National
Toxicology
Program's
Human
Exposure
Initiative
is
intended
to
help
set
priorities
for
chemical
toxicological
testing
and
might
gather
baseline
information
on
chemicals
and
chemical
mixtures
occurring
in
the
population
that
are
not
necessarily
already
known
as
harmful.

32Because
of
its
emphasis
on
evaluating
total
human
exposure,
NHEXAS
emphasized
those
chemicals
that
can
be
measured
in
multiple
environmental
media
(
for
example
in
air,
water,
and
food)
as
well
as
human
tissues.

33CDC's
laboratory
officials
indicated
that
their
choice
of
chemicals
is
determined
by
the
availability
of
high­
quality
analytical
methods
with
adequate
throughput,
whether
the
chemical
is
a
known
or
suspected
cause
of
health
problems,
whether
the
chemical
is
on
EPA
and
ATSDR
priority
lists,
the
number
of
persons
likely
exposed,
and
the
availability
of
funding
from
collaborators.
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Officials
we
interviewed
raised
many
other
concerns
that
would
need
to
be
addressed
when
trying
to
coordinate
efforts
among
multiple
federal
and
state
agencies
and
programs:

°
For
what
specific
purpose(
s)
will
these
data
be
collected?
°
What
chemicals
should
be
measured,
in
what
order,
how
frequently,
and
in
what
specific
tissues?
34
°
What
chemicals
should
be
measured
concurrently
with
or
only
through
personal
environmental
measurements?
°
What
is
the
best
way
to
identify
populations
that
might
be
at
higher
risk
of
exposure?
°
What
chemicals
should
be
monitored
in
humans
nationally,
versus
regionally
or
locally?
35
°
How
can
exposure
data
be
coupled
with
our
increasing
knowledge
about
the
effect
genetic
factors
have
on
risk
from
exposure
to
improve
the
understanding
about
an
individual's
risk
from
chemical
contaminants?
°
What
role
should
state
agencies
have
in
conducting
human
exposure
measurements
and
in
planning
federal
efforts?

The
fragmentation
of
responsibilities
and
efforts
for
assessing
human
exposure
reflect
larger
issues
in
the
fragmentation
of
responsibility
for
environmental
health.
For
over
a
decade,
a
number
of
studies
have
pointed
34Several
officials
pointed
to
the
importance
of
developing
a
breast
milk
monitoring
program.
Many
environmental
agents
are
fat
soluble
and
are
released
into
breast
milk
at
significant
concentrations.
Examples
include
dioxins
and
PCBs.
According
to
NIEHS
researchers,
6
months
of
nursing
could
result
in
dioxin
or
PCB
concentrations
in
infants
which
are
10
times
higher
than
in
the
mother.
Breast
milk
monitoring
programs
operate
in
several
European
countries
including
Sweden,
Germany,
and
the
Netherlands.

35EPA's
scientific
advisers'
review
of
the
NHEXAS
pilot
surveys
illustrates
some
of
the
tradeoffs
in
determining
the
appropriate
balance
between
large
population
surveys
and
more
targeted
follow­
up
surveys.
The
advisers
reported
that
population
studies
are
the
only
means
for
collecting
baseline
information
for
such
uses
as
trend
analysis.
NHANES
is
an
example
of
such
a
probability
study.
On
the
other
hand,
more
targeted
special
studies
tend
to
assess
high­
end
exposure
groups
more
precisely.
Additionally,
the
review
illustrated
how
total
exposure
data
may
be
unnecessary
to
collect
for
chemicals
at
a
national
level,
depending
on
the
chemical.
The
advisers
pointed
out
that
targeted
special
studies
can
be
used
to
identify
sources
and
factors
associated
with
high­
end
exposures.
While
identification
of
major
sources,
media,
and
pathways
for
populations
experiencing
high
exposures
are
essential
to
reduce
unacceptably
high
risks,
if
the
majority
of
the
national
population
is
exposed
to
pollutants
at
levels
under
health­
related
benchmarks,
source
identification
for
such
exposures
is
not
a
priority
from
a
health
standpoint.
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Health
Data
Needs
to
the
need
for
improved
coordination
between
regulatory
and
health
agencies
(
see
table
4).

Table
4:
Examples
of
Reports
Calling
for
Coordination
in
Environmental
Health
Potential
for
Convergence
of
Effort
Is
Increasing
The
importance
of
planning
and
coordination
is
magnified
by
the
possible
overlap
in
current
plans
to
expand
human
exposure
monitoring
efforts.
This
potential
can
be
seen
in
HHS'
and
EPA's
plans
for
NHANES
and
proposed
expansions
of
the
NHEXAS
pilots.
Although
nearly
two­
thirds
of
the
chemicals
measured
in
the
NHEXAS
pilot
surveys
are
currently
measured
or
planned
for
NHANES,
the
two
efforts
have
taken
differing
approaches
in
the
past
to
monitoring
the
population's
exposure
to
these
chemicals.
36
The
NHEXAS
pilots
have
focused
on
"
total"
exposure,
which
entailed
measurements
in
human
tissues,
water,
air,
food,
dust,
and
other
potential
sources
in
participants'
living
environments,
and
data­
gathering
has
focused
on
three
selected
regions
of
the
country.
Total
exposure
Report
Description
Environmental
Health
Data
Needs:
An
Action
Plan
for
Federal
Public
Health
Agencies
(
Public
Health
Foundation,
1997)
Called
for
the
federal
government
to
facilitate
stronger
ties
between
environmental
protection
and
public
health
agencies,
perhaps
by
strengthening
organizational
links
and
coordinating
funding
for
federal
(
EPA
and
HHS)
programs.
Also
indicated
that
priority
environmental
health
information
needs
included
more
complete
exposure
data,
including
laboratory
data
such
as
biological
measurements.

Burke,
Shalauta,
and
Tran,
The
Environmental
Web:
Impact
of
Federal
Statutes
on
State
Environmental
Health
and
Protection
(
Public
Health
Service,
Jan.
1995)
Found
that
progress
in
understanding
the
relationship
between
human
health
and
the
environment
will
require,
among
other
actions,
improved
cooperation
between
the
many
health
and
environmental
agencies
at
the
federal,
state,
and
local
levels.

Researching
Health
Risks
(
Office
of
Technology
Assessment,
1993)
Reported
that
although
agencies
are
expanding
their
research
efforts,
few
incentives
exist
for
them
to
collaborate,
and
the
lack
of
collaboration
can
only
hinder
progress
in
applying
newly
developed
techniques
and
knowledge
to
understanding
the
potential
links
between
exposure
and
adverse
health
effects.

The
Potential
for
Linking
Environmental
and
Health
Data
(
National
Governors'
Association,
1990)
Reported
that
linkage
of
environmental
and
health
data
to
investigate
possible
connections
between
exposure
and
adverse
health
effects
cannot
occur
without
interagency
communication
and
cooperation,
which
rarely
evolves
naturally.

The
Future
of
Public
Health
(
Institute
of
Medicine,
1988)
Found
that
separating
environmental
health
from
public
health
programs
impeded
desirable
coordination
and
could
limit
the
depth
of
analyses
given
to
the
health
implications
of
environmental
hazards.

36The
follow­
up
to
the
NHEXAS
pilots
has
not
been
planned,
so
the
identity
of
the
chemicals
to
be
measured
is
not
known.
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Needs
measurements
can
help
identify
those
sources
that
most
contribute
to
exposure
 
a
critical
part
of
determining
how
to
take
action
to
reduce
or
prevent
exposures.
However,
measuring
total
exposure
requires
several
types
of
laboratory
measurements
and
is
thus
more
expensive.
By
contrast,
NHANES
has
focused
its
exposure
monitoring
on
human
biological
measurements
and
on
a
sample
that
is
generally
representative
of
the
nation
as
a
whole.
Biological
monitoring
data
demonstrate
exposure
from
all
sources,
but
determining
exposure
sources
usually
requires
additional
environmental
measurements.
Other
than
the
few
chemicals
it
covered,
NHANES
has
historically
been
considered
an
awkward
vehicle
for
including
exposure
monitoring
 
in
large
part
because
of
its
wide
range
of
competing
goals
and
lack
of
a
primary
commitment
to
monitoring
tissues
for
exposures.

Changes
to
the
1999
NHANES,
such
as
the
following,
show
a
greater
emphasis
in
environmental
health.
These
changes
along
with
EPA's
plans
to
expand
NHEXAS
suggest
a
convergence
of
the
two
approaches
and
a
growing
and
overlapping
interest
among
agencies
in
exposure
measurement
and
monitoring.

°
NHANES
now
has
a
goal
of
monitoring
exposures.
Starting
with
NHANES
1999,
CDC
formalized
its
commitment
to
monitoring
trends
in
the
nation's
environmental
exposures
by
establishing
this
as
a
stated
goal
of
NHANES.
37
In
line
with
this
goal,
CDC's
laboratory
plans
to
issue
37At
this
writing,
NHANES'
goals
are
to
(
1)
estimate
the
number
and
percentage
of
persons
in
the
United
States
and
designated
subgroups
with
selected
diseases
and
risk
factors;
(
2)
monitor
trends
in
the
prevalence,
awareness,
treatment,
and
control
of
selected
diseases;
(
3)
monitor
trends
in
risk
behaviors
and
environmental
exposures;
(
4)
analyze
risk
factors
for
selected
diseases;
(
5)
study
the
relationship
between
diet,
nutrition,
and
health;
(
6)
explore
emerging
public
health
issues
and
new
technologies;
and
(
7)
establish
a
national
probability
sample
of
genetic
material
for
future
genetic
research.
CDC
officials
told
us
that
the
emerging
focus
in
NHANES
on
environmental
health
issues
reflects
advances
in
technology
as
well
as
the
public's
increasing
priority
for
understanding
the
impacts
of
environment
on
health.
Part
of
CDC's
responsibility
is
to
report
on
environmental
hazards
and
determinants
of
health.
Section
306
of
the
Public
Health
Service
Act
(
42
U.
S.
C.
242k)
directs
the
National
Center
for
Health
Statistics,
the
CDC
agency
that
conducts
NHANES,
to
collect
statistics
on
subjects
such
as
the
extent
and
nature
of
illness
and
disability
of
the
population;
environmental,
social,
and
other
health
hazards;
determinants
of
health;
health
resources;
and
utilization
of
health
care.
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this
year
a
"
National
Exposure
Report
Card"
using
NHANES
samples.
38
This
goal
is
similar
to
EPA's
goal
as
proposed
for
NHEXAS'
follow­
up
survey
 
to
document
the
status
and
trends
of
the
national
distributions
of
human
exposure
to
potentially
high­
risk
chemicals.

°
NHANES
will
include
selected
environmental
measurements.
Starting
with
NHANES
1999,
environmental
measurements,
such
as
contaminant
levels
in
water
and
house
dust,
and
levelsmeasured
through
personal
air
monitors
worn
by
participants
will
be
included
in
the
survey
to
help
identify
potential
sources
of
exposure.
39
°
NHANES
will
be
conducted
continuously
rather
than
periodically,
allowing
for
more
flexibility
in
the
measurements
it
includes.
According
to
CDC
officials,
the
new
annual
sampling
design
will
enable
them
to
include
emerging
and
changing
priorities
in
the
data
collected
through
the
survey
and
thus
allow
for
a
broader
collection
of
data
than
in
previous
surveys,
including
exposure
and
measurements
in
people's
personal
environments.

Other
planned
changes
to
NHANES
and
NHEXAS
also
indicate
a
growing
overlap
in
approaches
and
interests.
For
example,
pending
analysis
and
evaluation
of
its
pilot
surveys,
EPA
is
proposing
to
expand
NHEXAS
beyond
the
regional
focus
of
its
pilot
to
include
a
nationally
representative
sample
similar
to
the
framework
of
NHANES.
Also,
both
CDC
and
EPA
would
like
to
eventually
include
a
component
in
NHANES
and
NHEXAS
to
monitor
special
populations.
EPA's
proposed
expansion
of
NHEXAS
would
eventually
include
"
special
studies"
to
examine
high­
end
exposures
in
more
detail
and
with
greater
precision.
Small
populations
for
further
study
would
be
identified
through
the
national
survey.
CDC
also
plans
to
add
a
component
to
NHANES
that
will
gather
selected
NHANES
health
and
nutrition
data,
possibly
including
exposure
measurements,
on
specific
subpopulations
in
geographic
areas
of
interest
or
among
specific
racial
or
ethnic
minority
populations.
This
effort
to
add
a
subpopulation
component
38According
to
CDC
laboratory
officials,
the
first
report
card
will
provide
data
on
exposure
levels
of
the
population
to
25
chemicals
that
have
not
yet
been
determined.
These
might
include
selected
heavy
metals,
indoor
air
pollutants,
nonpersistant
pesticides,
and
phthalates.

39Because
of
the
wide
range
of
other
health
and
nutrition
questions
addressed
in
NHANES,
environmental
measurements
currently
included
are
less
extensive
than
those
included
in
NHEXAS
because,
for
example,
food
and
beverage
samples
are
not
conducted.
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Health
Data
Needs
to
NHANES
was
initiated
in
response
to
the
needs
of
state
health
officials
and
others
for
local
level
data.

Funding
Is
Sporadic,
and
Funding
Priorities
Change
Part
of
the
difficulty
in
collaborating
and
in
planning
human
exposure
monitoring
efforts
to
meet
longer­
term
needs
may
also
arise
from
issues
of
sporadic
funding
and
resources
to
support
these
efforts.
As
compared
to
the
hundreds
of
millions
spent
on
monitoring
contaminants
in
environmental
media,
we
estimate
that
less
than
$
7
million
was
spent
collectively
by
CDC
(
including
ATSDR)
and
EPA
on
their
respective
human
exposure
efforts
in
1999.40
Neither
CDC
nor
EPA
has
provided
a
dedicated
funding
stream
for
their
exposure
measurement
efforts.
Funding
for
efforts
has,
to
a
large
extent,
depended
on
priorities
established
year
to
year.
For
example,
funding
for
the
exposure
and
other
environmental
components
of
NHANES
depends
to
some
extent
on
the
interests
of
other
federal
agencies
and
their
willingness
to
pay
for
related
data
gathering
and
analysis.
41
CDC
estimated
it
would
spend
about
$
4.7
million
for
laboratory
measurements
and
laboratory
staff
costs
in
1999
for
NHANES­
related
exposure
measurements
such
as
lead,
mercury,
cotinine,
heavy
metals,
pesticides,
volatile
organic
compounds,
and
other
chemical
classes.
Interagency
agreements
document
the
receipt
of
about
$
1.2
million
from
collaborators
for
some
of
those
laboratory
measurements.
If
other
agencies
do
not
pay
CDC
to
conduct
laboratory
tests
 
with
the
exception
of
some
"
core"
measurements,
such
as
lead
 
CDC
performs
tests
as
time
and
laboratory
resources
allow.
For
example,

40NIEHS­
CDC
interagency
agreements
document
that
NIEHS
had
provided
about
$
3.3
million
to
CDC
between
fiscal
years
1996
and
2000
for
performing
environmental
exposure
measurements
for
its
Human
Exposure
Initiative.
No
funding
was
provided
in
fiscal
year
1999.

41NHANES
1999,
for
example,
received
$
15.9
million
in
appropriated
funding
and,
according
to
CDC
officials,
an
additional
$
6.8
million
from
collaborating
institutions.
Interagency
agreements
related
to
environmental
measurements
performed
in
conjunction
with
NHANES
document
the
receipt
of
about
$
1.4
million
from
collaborators
at
EPA
and
other
agencies
for
environmental
exposure
measurements.
In
addition
to
EPA's
support
for
measurement
of
certain
chemicals
in
human
tissues,
an
estimated
$
125,000
was
received
from
the
Department
of
Housing
and
Urban
Development
for
performing
dust
sampling
and
an
estimated
$
30,000
from
the
Mickey
Leland
National
Urban
Air
Toxics
for
personal
measurements
of
volatile
organic
compounds.
CDC
laboratory
officials
indicated
that
the
increase
to
their
fiscal
year
2000
funding
for
the
environmental
health
laboratory
has
improved
their
ability
to
support
needed
laboratory
measurements
for
NHANES
and
other
efforts.
This
funding
increased
by
about
$
5
million
between
fiscal
years
1999
and
2000.
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although
CDC
initially
proposed
for
the
survey
starting
in
1999
to
measure
up
to
210
chemicals
in
tissues
of
a
subset
of
NHANES
survey
participants,
CDC
officials
indicated
that
those
chemicals
could
be
measured
only
as
resources
allowed.
42
At
the
time
of
our
review,
a
CDC
laboratory
official
indicated
that
resources
might
allow
them
to
include
about
74
chemicals
in
1999
and
2000.

EPA's
commitment
to
funding
NHEXAS
also
remains
uncertain.
EPA
officials
estimated
that
approximately
$
20
million
was
spent
on
NHEXAS
from
1993
through
1999
 
with
a
decreasing
amount
designated
to
the
project
in
1999
and
2000.
While
EPA's
independent
scientific
advisers
commended
the
design
for
NHEXAS
and
said
it
could
be
the
basis
for
an
effective
national
program,
they
expressed
concerns
about
the
limited
resources
allocated
to
analyze
the
data
gathered
in
the
pilot
projects.
43
At
a
national
level,
EPA
has
dedicated
approximately
three
full­
time
positions
to
evaluate
the
data
from
the
NHEXAS
pilots
and
design
future
expansions.

Better
Linkages
to
Program
Goals
and
Performance
Monitoring
Needed
The
Government
Performance
and
Results
Act
of
1993
(
Results
Act)
provides
federal
agencies
a
structured
framework
to
coordinate
efforts
in
crosscutting
programs
when
agency
missions
overlap.
The
Results
Act
requires
federal
agencies,
as
part
of
their
mandated
responsibilities,
to
prepare
annual
performance
plans
that
discuss
agency
goals
and
performance
measures.
Past
reviews
have
shown
that
EPA,
HHS,
and
other
federal
agencies
have
not
fully
used
the
Results
Act
planning
process
to
explain
how
each
would
coordinate
crosscutting
efforts
with
other
agencies.
Few
agency
plans
attempt
the
challenging
task
of
discussing
planned
strategies
for
coordination
and
establishing
complementary
performance
goals
and
common
or
complementary
performance
measures.

A
major
weakness
of
EPA's
fiscal
year
2000
Annual
Performance
Plan
was
the
lack
of
sufficient
detail
describing
crosscutting
goals
and
activities
or
how
EPA
planned
to
coordinate
with
other
federal
agencies
on
related
42According
to
CDC
officials,
uncertain
funding
may
limit
their
ability
to
perform
NHANES
measurements
for
dioxins,
furans,
coplanercoplanar
PCBs,
phytoestrogens,
certain
heavy
metals,
phthalates,
and
polyaromatic
hydrocarbons.

43EPA
officials
indicated
that
at
the
individual
study
level,
approximately
$
250,000
was
allocated
for
analyses
of
the
NHEXAS
pilot
data
in
fiscal
year
1999;
EPA
plans
to
spend
approximately
$
170,000
in
fiscal
year
2000.
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strategic
or
performance
goals.
44
For
example,
under
its
plan's
"
safe
food"
objective,
EPA
discusses
coordinating
with
HHS
and
other
agencies
to
reduce
health
risks
from
pesticides.
However,
it
did
not
outline
specific
projects
and
strategies,
responsibilities,
and
products
that
must
be
coordinated
for
EPA
to
accomplish
its
goals.
Similarly,
HHS'
performance
plan
lacked
details
regarding
how
crosscutting
activities
and
goals
would
be
coordinated
with
other
agencies.

In
their
fiscal
year
2001
performance
plans,
EPA
and
CDC
make
limited
use
of
human
exposure
data
to
measure
or
validate
performance,
and
neither
agency
describes
how
data
collection
efforts
relate
to
complementary
goals
of
other
federal
agencies.
For
example,
EPA
and
CDC
have
the
common
goal
of
reducing
childhood
lead
poisoning,
but
only
CDC
uses
data
on
blood
lead
levels
to
validate
progress
toward
this
goal.
Although
EPA
has
goals
that
are
clearly
related
to
reducing
human
exposure
to
other
toxic
chemicals,
the
human
exposure
data
collected
by
EPA
and
CDC
have
largely
not
been
linked
with
or
used
to
measure
progress.
Such
data
show
potential
for
helping
elucidate
federal
progress
in
environmental
efforts,
but
EPA
has
not
yet
acted
to
fully
realize
such
potential.
For
example,
NHEXAS
data
are
used
to
help
assess
children's
exposure
to
pesticides.
However,
a
related
goal
to
reduce
public
exposure
to
pesticides
does
not
use
human
exposure
data;
instead,
it
relies
on
the
number
of
activities
to
educate
agricultural
workers
and
the
public.
The
effectiveness
of
these
efforts
could
be
assessed,
in
part,
through
measured
reductions
in
actual
human
exposure
to
specific
pesticides.
During
1999,
CDC
maintained
a
goal
to
develop
methods
to
measure
toxic
substances
in
humans
and
added
a
goal
to
measure
and
report
on
human
exposure
to
toxic
substances.
However,
neither
goal
discusses
how
CDC
will
coordinate
with
EPA
and
other
federal
programs
in
meeting
these
goals
and
ensuring
that
newly
developed
methods
and
measured
substances
meet
priority
data
needs.

Successful
Models
for
Planning
and
Coordination
Point
to
the
Need
for
High­
Level
Mandate,
Process
for
Inclusion,
and
Mechanism
for
Reporting
Program
officials
at
HHS
and
EPA
told
us
in
early
2000
that
they
were
discussing
the
merits
of
establishing
a
new
interagency
program
in
human
44See
Observations
on
the
Environmental
Protection
Agency's
Fiscal
Year
2000
Performance
Plan(
GAO/
RCED­
99­
237R)
July
20,
1999.
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exposure
monitoring.
45
At
the
time
of
our
review,
the
proposal
was
in
early
stages
of
discussion
and
officials
had
not
clarified
how
a
new
program
would
consider
states'
information
needs,
differ
from
or
relate
to
NHANES
and
the
NHEXAS
pilot
surveys,
or
resolve
past
issues
about
differing
agency
goals
and
priorities.

Several
experts
and
agency
officials
have
pointed
to
successful
models
of
interagency
collaboration
in
environmental
health
issues
that
could
help
shape
an
HHS­
EPA
interagency
effort.
One
such
model
is
the
collaboration
on
children's
environmental
health
issues.
In
this
case,
Executive
Order
13045,
signed
by
the
President
on
April
21,
1997,
established
a
Task
Force
on
Environmental
Health
Risks
and
Safety
Risks
to
Children
to
develop
and
recommend
federal
strategies
for
children's
environmental
health
and
safety.
Among
the
elements
that
have
been
cited
as
contributing
to
success
were
a
clear
mandate
to
collaborate
and
a
process
to
respond
to
the
input
and
data
needs
of
different
stakeholders.
According
to
involved
officials,
a
high­
level
interagency
work
group
has
worked
closely
to
address
its
charges.
These
charges
include
developing
general
policy
and
annual
priorities;
a
coordinated
federal
research
agenda;
recommendations
for
partnerships
among
federal,
state,
local,
and
tribal
governments
and
the
private,
academic,
and
nonprofit
sectors;
and
identifying
high­
priority
initiatives
to
advance
protection
of
children's
environmental
health.
46
A
second
model
with
a
top­
down
mandate
and
a
process
to
respond
to
stakeholders
is
NTP,
established
in
1978
as
an
HHS­
wide
effort
to
provide
regulatory
and
research
agencies
needed
information
about
potentially
toxic
and
hazardous
chemicals
nationwide
and
to
strengthen
the
science
base
in
toxicology.
According
to
officials,
part
of
NTP's
success
in
fostering
collaboration
are
an
inclusive
executive
committee
and
an
established
process
for
decisionmaking.
The
NTP
Executive
Committee,
which
provides
policy
oversight
of
NTP,
includes
agencies
outside
of
HHS,
such
as
EPA
and
the
Consumer
Product
Safety
Commission.
The
NTP
Executive
Committee
also
serves
as
a
decisionmaking
body,
in
that
members
cast
votes
on
key
issues,
such
as
prioritization
of
chemicals
for
study
and
for
45This
effort
was
coordinated
through
the
White
House
Office
of
Science
and
Technology
Policy.

46Executive
Order
13045
also
indicates
such
strategies
are
to
include
proposals
to
enhance
public
outreach
and
communication
and
a
statement
regarding
the
desirability
of
new
legislation
to
fulfill
or
promote
the
purposes
of
the
order.
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listing
in
NTP's
Report
on
Carcinogens.
47
Involved
officials
believe
the
voting
requirement
helps
move
key
issues
forward
and
provides
an
effective
means
of
resolving
disagreements.
NTP
also
has
an
inclusive
process
for
identifying
chemicals
to
be
considered
by
the
Executive
Committee.
NTP's
chemical
testing
nominations
are
solicited
from
sources
in
academia,
federal
and
state
regulatory
and
health
agencies,
industry,
and
unions,
as
well
as
environmental
groups
and
the
general
public.

Several
officials
indicated
that
reports
on
exposures
in
the
national
population
to
toxic
chemicals
are
needed
to
help
inform
policymakers,
researchers,
and
the
public.
Specifically,
such
reports
can
help
identify
serious
human
health
risks,
help
officials
link
exposures
to
sources,
determine
appropriate
interventions
to
help
reduce
these
risks,
and
document
the
effectiveness
of
interventions
in
reducing
exposures.
Moreover,
agencies
could
use
such
reports
to
validate
or
measure
progress
in
meeting
goals
established
under
the
Results
Act.
A
key
element
of
NTP
is
its
biennial
reports.
As
informational
scientific
and
public
health
documents,
these
reports
are
not
only
used
by
federal
and
state
agencies
but
are
considered
an
important
medium
for
informing
the
public
and
policymakers
on
the
status
of
substances
considered
likely
to
be
carcinogenic
for
humans.

Conclusions
The
nation
has
a
long
way
to
go
in
measuring
human
exposures
to
potentially
harmful
chemicals.
While
federal
efforts
are
increasingly
covering
chemicals
of
potential
concern,
there
are
substantial
gaps
in
current
information
on
exposure
levels,
the
health
risks
that
result,
and
those
who
may
be
most
at
risk.
Recent
advances
in
laboratory
technology
show
promise
for
improving
the
collection
and
analysis
of
some
of
the
information
needed
to
understand
and
measure
human
exposures.
However,
a
more
long­
term
and
concerted
effort
to
address
infrastructure
and
scientific
limitations
in
measuring
exposure
will
be
required
if
substantive
progress
is
to
be
made.
Applying
and
continually
improving
47The
Director
of
NTP
issues
the
Report
on
Carcinogens
pursuant
to
a
1978
amendment,
section
301(
B)(
4)
of
the
Public
Health
Services
Act,
which
requires
the
Secretary
of
HHS
to
publish
a
list
of
all
substances
that
are
either
known
to
be
human
carcinogens
or
may
reasonably
be
anticipated
to
be
human
carcinogens
and
to
which
a
significant
number
of
persons
residing
in
the
United
States
are
exposed.
NTP
issues
a
revised
Report
on
Carcinogens
every
2
years.
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upon
these
advances
to
cover
an
increasing
number
of
chemicals
and
issues
will
require
both
time
and
resources.
CDC's
laboratory
to
date
has
been
able
to
meet
many
demands
for
human
exposure
data
for
federal
and
state
measurement
and
monitoring
efforts.
However,
its
capacity,
given
current
resources,
will
continue
to
limit
progress
to
develop
new
methods
and
include
more
people
and
chemicals
in
federal
and
state
efforts.

Federal
agencies
are
currently
planning
whether
and
how
they
can
expand
existing
programs
to
meet
the
significant
needs
for
human
exposure
data.
Collaboration
in
such
planning
is
essential,
because
agencies
have
different
capacities
and
skills,
and
separate
attempts
have
fallen
short
of
supporting
the
large
efforts
that
are
needed.
So
far,
no
clear
strategy
has
emerged
for
how
to
carry
out
this
major
task,
particularly
given
the
growing
and
overlapping
interests
among
many
agencies
for
understanding
and
measuring
human
exposures
to
potentially
harmful
chemicals.
In
our
view,
developing
such
a
strategy
is
a
challenging
but
necessary
first
step.

In
the
meantime,
state
and
local
health
officials
must
try
to
understand
and
communicate
the
risks
from
environmental
contaminants
to
concerned
citizens
 
a
difficult,
if
not
impossible,
task
when
information
is
unavailable
to
help
them
interpret
the
risks
from
the
exposures
citizens
face
in
their
daily
environments.
State
officials
indicate
they
need
more
of
the
information
that
is
collected
through
federal
efforts
to
help
interpret
those
levels
faced
by
citizens
in
their
states.
And
to
collect
measurements
for
their
studies
and
investigations,
state
officials
are
faced
with
finding
laboratories
that
have
the
equipment
and
capacity
to
perform
the
complex
measurements.
Federal
capacity,
largely
centered
at
CDC,
cannot
meet
states'
needs
in
many
situations,
and
laboratory
capacity
is
lacking
in
most
states.

To
help
meet
the
gaps
in
environmental
exposure
data
at
all
levels
of
government,
EPA
and
the
various
HHS
agencies
with
environmental
health
responsibilities
need
to
work
closely
together
to
forge
a
strategic
plan
laying
out
the
necessary
next
steps
for
addressing
human
exposure
information
and
concerns.
In
addition
to
considering
states'
needs
and
capacities
for
collecting
human
exposure
data,
such
a
plan
could
°
provide
long­
term
structure
to
human
exposure
monitoring
as
an
interagency
effort,
°
establish
a
mechanism
for
setting
program
priorities
in
line
with
agency
goals
and
performance
measures,
°
clarify
agency
roles
and
minimize
duplication,
and
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°
help
agencies
share
expertise.

Policymakers,
agencies,
and
the
public
seek
many
types
of
information
on
exposure
trends
and
levels
in
the
national
population
as
well
as
for
groups
considered
potentially
at
risk
of
disproportionate
exposures.
Resolution
is
also
needed
on
what
information
should
be
reported
on
national
trends
and
levels
of
exposure.
A
strategic
plan
could
help
agencies
resolve
the
many
different
informational
needs
to
determine
what
exposure
information
should
be
reported
and
how
agencies
can
work
together
to
report
such
information.

Recommendations
to
the
Secretary
of
HHS
and
the
Administrator
of
EPA
We
recommend
that
the
Secretary
of
HHS
and
the
Administrator
of
EPA
develop
a
coordinated
federal
strategy
for
the
short­
and
long­
term
monitoring
of
human
exposures
to
potentially
toxic
chemicals.
In
developing
such
a
strategy,
the
Secretary
and
the
Administrator
should
assess
the
need
for
an
interagency
program
to
collect
and
report
data
on
human
exposures,
the
extent
current
surveys
and
agency
efforts
can
be
used
as
part
of
such
an
effort,
and
the
funding
needs
and
sources
to
sustain
a
viable
program
for
monitoring
human
exposures
to
toxic
substances.
Such
a
strategy
should
°
address
individual
agency
needs
and
expertise,
°
provide
a
framework
for
coordinating
efforts
to
gather
data
needed
to
improve
understanding
of
human
exposures,
°
assess
needed
federal
and
state
laboratory
capacity,
°
establish
research
priorities
for
laboratory
methods
development
and
a
mechanism
or
process
for
setting
chemical
monitoring
priorities,
°
develop
a
framework
for
identifying
at­
risk
populations,
and
°
consider
states'
informational
needs.

We
further
recommend
that
the
agencies
identify
common
or
complementary
performance
goals
or
measures
to
reduce,
monitor,
or
develop
methods
for
measuring
human
exposures
to
toxic
chemicals.
Such
goals
or
measures
can
be
a
basis
for
structuring
and
supporting
interagency
collaborations
to
collect
and
use
human
exposure
data.

As
part
of
this
coordinated
strategy,
we
recommend
that
the
Secretary
of
HHS
and
Administrator
of
EPA
periodically
publish
a
report
on
levels
and
trends
in
the
national
population
of
exposures
to
selected
toxic
substances.
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Data
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Agency
Comments
We
provided
HHS
and
EPA
an
opportunity
to
comment
on
a
draft
of
this
report.
Both
agencies
generally
concurred
with
our
conclusions
and
recommendations
 
that
a
long­
term
coordinated
federal
strategy
was
needed
for
monitoring
human
exposures
to
potentially
toxic
chemicals
and
that
such
efforts
could
be
linked
through
common
or
complementary
performance
goals
 
and
indicated
that
they
would
work
together
to
implement
our
recommendations.
(
See
apps.
IV
and
V,
respectively.)
HHS
and
EPA
also
both
stressed
the
importance,
as
discussed
in
our
report,
of
expanding
the
scope
of
their
efforts
to
monitor
and
measure
human
exposures
to
toxic
chemicals
beyond
the
limited
number
of
chemicals
covered
today.
To
support
such
expansions,
HHS
noted
the
importance
of
additional
resources
for
improving
laboratory
capacity
and
methods.

HHS
and
EPA
provided
several
other
comments
raising
points
that
one
or
both
agencies
consider
important
to
monitoring
human
exposures
to
toxic
chemicals.
These
included
the
need
to
(
1)
coordinate
any
exposure
monitoring
in
the
general
population
with
monitoring
of
occupational
exposures;
(
2)
consider
adding
the
monitoring
of
breast
milk
in
a
national
program;
(
3)
depending
on
the
chemical
and
the
purpose
for
the
data
collection,
consider
measures
of
human
exposure
other
than
the
concentration
in
human
tissues
for
collection;
and
(
4)
consider
the
option
of
expanding
the
scope
of
NHANES
as
a
means
of
improving
data
needed
to
identify
potentially
at­
risk
subgroups.
We
agree
that
the
points
raised
in
these
comments
are
important
and
that
they
should
be
considered
during
development
of
any
coordinated
federal
strategy.

EPA
also
said
that
additional
federal
partners,
including
the
Departments
of
Defense,
Transportation,
and
Energy
should
participate
in
developing
and
supporting
a
coordinated
federal
strategy.
We
agree
that
it
would
be
appropriate
to
obtain
input
from
all
involved
and
interested
agencies.
HHS
and
EPA
also
provided
a
number
of
clarifying
and
technical
comments,
which
we
incorporated
where
appropriate.

We
are
sending
copies
of
this
report
to
the
Honorable
Donna
E.
Shalala,
Secretary
of
HHS,
and
the
Honorable
Carol
M.
Browner,
Administrator,
EPA.
We
are
also
sending
copies
to
Jeffrey
P.
Koplan,
Director,
CDC,
and
Administrator,
ATSDR;
Ruth
Kirschstein,
Acting
Director,
NIH;
Kenneth
Olden,
Director,
NIEHS;
Richard
J.
Jackson,
Director,
National
Center
for
Environmental
Health;
Edward
J.
Sondik,
National
Center
for
Health
Statistics;
Norine
Noonan,
Assistant
Administrator
for
Research
and
B­
282172
Page
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Health
Data
Needs
Development,
EPA;
and
other
interested
parties.
We
will
make
copies
available
to
others
upon
request.

If
you
or
your
staff
have
any
questions,
please
contact
me
at
(
202)
512­
7119.
Other
major
contributors
are
included
in
appendix
VI.

Janet
Heinrich
Associate
Director,
Health
Financing
and
Public
Health
Issues
B­
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List
of
Requesters
The
Honorable
Nancy
Pelosi
House
of
Representatives
The
Honorable
Maxine
Waters
House
of
Representatives
The
Honorable
Eleanor
Holmes
Norton
House
of
Representatives
The
Honorable
Patsy
Mink
House
of
Representatives
The
Honorable
Anne
G.
Eshoo
House
of
Representatives
The
Honorable
Nydia
Velazquez
House
of
Representatives
The
Honorable
John
Conyers
House
of
Representatives
The
Honorable
Louise
Slaughter
House
of
Representatives
The
Honorable
Henry
A.
Waxman
House
of
Representatives
Page
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Needs
Appendix
I
Appendixes
Objectives,
Scope,
and
Methodology
AppendixI
Nine
members
of
the
Congress
asked
us
to
study
the
nation's
data
collected
to
assess
human
exposure
to
potentially
toxic
chemicals
in
the
environment.
As
agreed
with
our
requesters,
we
focused
our
work
primarily
on
efforts
to
measure
chemical
exposures
in
human
tissue
samples,
such
as
blood,
hair,
and
urine.
This
report
discusses
(
1)
the
extent
to
which
state
and
federal
agencies
 
specifically,
HHS
and
EPA
 
collect
human
exposure
data
on
potentially
harmful
chemicals,
including
data
to
identify
at­
risk
populations,
and
(
2)
the
main
barriers
hindering
further
progress
in
such
efforts.

Scope
of
Our
Review
Although
laboratory
measurements
of
chemical
exposure
are
only
one
part
of
the
data
collected
to
address
environmental
health
concerns,
they
merit
attention
because
new
technology
makes
it
increasingly
easy
to
measure
the
degree
to
which
a
chemical
has
been
absorbed
into
human
tissues.
Such
measurements
are
often
a
more
accurate
and
useful
approach
to
assessing
exposure
than
environmental
measurements,
according
to
public
health
experts.

Because
federal
agencies
that
collect
human
exposure
data
collect
these
data
for
different
purposes,
we
were
not
able
to
assess
the
overall
adequacy
of
the
nation's
efforts
to
address
environmental
health
concerns.
Therefore,
we
focused
our
work
at
the
federal
level
on
the
efforts
of
two
agencies
 
HHS
and
EPA
 
and
the
subcomponents
of
these
agencies
involved
in
exposure
measurement
and
monitoring
in
the
U.
S.
population:

°
EPA's
Office
of
Research
and
Development,
°
HHS'
National
Center
for
Environmental
Health
(
NCEH),
°
HHS'
National
Center
for
Health
Statistics
(
NCHS),
°
HHS'
Agency
for
Toxic
Substances
and
Disease
Registry
(
ATSDR),
and
°
HHS'
National
Institute
of
Environmental
Health
Sciences
(
NIEHS).

We
focused
our
work
mainly
on
nonoccupational
environmental
exposure
to
chemical
agents
known
or
thought
to
pose
a
health
hazard
by
one
or
more
of
these
agencies.

To
gather
information
about
activities
of
state
officials,
we
surveyed
environmental
health
officials
in
state
public
health
agencies
and
conducted
site
visits
to
six
states.
Appendix
I
Objectives,
Scope,
and
Methodology
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Methodology
of
Our
Review
To
assess
the
extent
to
which
the
federal
agencies
we
reviewed
have
collected
human
exposure
data,
we
met
with
key
officials
responsible
for
efforts
intended
to
collect
human
exposure
data
at
each
agency.
We
focused
on
what
we
identified
as
being
the
most
significant
federal
efforts
in
human
exposure
assessment
at
EPA
and
HHS
related
to
nonoccupational
human
exposure
to
environmental
contaminants.
We
reviewed
four
major
activities:
EPA's
National
Human
Exposure
Assessment
Survey
(
NHEXAS),
CDC's
National
Health
and
Nutrition
Examination
Survey
(
NHANES),
NIEHS'
Human
Exposure
Initiative,
and
ATSDR's
exposure
investigation
activities
around
hazardous
waste
and
other
sites.
We
also
obtained
information
on
EPA's
National
Human
Adipose
Tissue
Survey
(
NHATS),
which
ended
in
1992.

We
also
interviewed
officials
and
obtained
documentation
on
how
these
various
programs
were
planned
and
organized
and
to
assess
the
extent
data
were
collected
in
a
manner
that
allows
the
identification
of
at­
risk
subpopulations
by
such
factors
as
income,
race
and
ethnicity,
age,
and
geographic
location.
We
obtained
relevant
budget
information
for
1999
and
reviewed
related
agency
performance
plans.

To
assess
barriers
to
progress
in
collecting
or
using
human
exposure
data,
we
interviewed
federal
officials
involved
in
such
efforts
about
past
and
current
views
on
such
barriers.
In
addition,
we
reviewed
the
general
literature
on
human
exposure
to
environmental
chemicals
and
interviewed
officials
from
organizations
representing
state
epidemiologists,
state
public
health
laboratory
directors,
local
public
health
officials,
the
chemical
industry,
environmental
advocates,
and
public
health
experts.

To
gather
nationwide
data
on
the
views
of
state
public
health
officials,
we
surveyed
officials
with
environmental
health
responsibilities
related
to
chemical
exposure
in
state
public
health
agencies.
We
identified
93
officials
in
each
of
the
50
states
and
the
District
of
Columbia
 
referred
to
collectively
as
states
 
with
assistance
from
the
Council
of
State
and
Territorial
Epidemiologists
and
officials
in
each
of
the
51
states.

We
also
conducted
on­
site
work
at
EPA,
CDC
agencies,
and
NIEHS
and
in
six
states
 
California,
Louisiana,
Massachusetts,
North
Carolina,
Oregon,
and
Washington.
These
six
states
were
selected
to
represent
diverse
geographic
areas
and
environmental
health
programs.
In
the
six
states,
we
interviewed
state
public
health
officials.
We
also
interviewed
officials
in
state
environmental
protection
and
agriculture
agencies,
academic
and
Appendix
I
Objectives,
Scope,
and
Methodology
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independent
researchers,
and
representatives
of
community
advocacy
organizations.

We
excluded
efforts
to
collect
human
exposure
data
within
occupational
settings
from
the
scope
of
our
review.
Similarly,
we
excluded
federally
supported
academic
and
private
sector
research
efforts.

Our
work
was
conducted
from
March
1999
through
March
2000
in
accordance
with
generally
accepted
government
auditing
standards.

Methodology
for
Chemical
List
Analyses
To
assess
the
extent
to
which
human
exposure
data
are
available
for
chemicals
of
high
concern
to
human
health,
we
analyzed
a
number
of
chemical
lists
maintained
by
HHS
and
EPA
agencies.
We
also
identified
chemicals
measured
through
HHS
and
EPA
representative
surveys.

Chemical
data
were
gathered
from
various
sources,
including
EPA's
Offices
of
Pesticide
Programs,
Air
and
Radiation,
Pollution
Prevention
and
Toxics,
and
Research
and
Development;
the
National
Toxicology
Program
(
NTP)
headquartered
at
NIEHS;
CDC's
ATSDR;
and
NCEH
and
NCHS
within
ATSDR.
Several
toxic
chemical
lists
were
identified
through
a
review
of
related
reports
and
literature
on
environmental
exposure
issues.
To
narrow
the
scope,
we
also
contacted
staff
in
relevant
offices
within
these
agencies
and
asked
them
to
identify
key
lists
of
chemicals
of
concern.
We
consulted
experts
and
public
health
laboratory
officials
at
the
Pew
Commission
for
Environmental
Health
and
the
Association
for
Public
Health
Laboratories.

From
the
many
available
chemical
lists,
we
judgmentally
selected
eight
based
on
our
assessment
that
each
list
contained
chemicals
thought
to
have
a
high
potential
for
causing
harm
to
human
health
and
input
and
recommendations
from
experts.
These
eight
lists,
which
contained
more
than
1,400
unique
chemicals,
provide
a
conservative
number
of
the
chemicals
agency
officials
consider
a
concern
for
human
health.
To
ensure
that
chemicals
with
more
than
one
name
were
not
included
more
than
once,
we
used
Chemical
Abstract
Service
numbers,
a
unique
identifier.
These
lists,
whether
singly
or
combined,
do
not
necessarily
reflect
the
highest
priorities
of
the
federal
government
or
the
agencies
or
programs
we
contacted.
The
lists
we
reviewed
are
described
below.

°
Chemicals
found
most
often
at
the
nation's
Superfund
sites:
HHS'
ATSDR,
which
conducts
public
health
assessments
or
other
health
investigations
for
populations
living
around
national
priority
hazardous
Appendix
I
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Scope,
and
Methodology
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waste
sites,
and
EPA
prepare
a
list,
in
order
of
priority,
of
hazardous
substances.
This
list
contains
substances
that
are
most
commonly
found
at
facilities
on
the
National
Priorities
List
(
Superfund)
and
pose
the
most
significant
potential
threat
to
human
health
due
to
their
known
or
suspected
toxicity
and
potential
for
human
exposure.
°
EPA's
list
of
toxics
of
concern
in
air:
The
Congress
established
the
original
list
of
188
hazardous
air
pollutants
that
EPA
would
regulate
through
the
Clean
Air
Act.
EPA
periodically
must
revise
the
list
to
add
or,
when
warranted,
remove
substances.
EPA
adds
substances
that
it
determines
to
be
air
pollutants
that
are
known
to
cause
or
may
reasonably
be
anticipated
to
cause
adverse
effects
to
human
health
or
adverse
environmental
effects.
°
Chemicals
harmful
because
of
their
persistence
in
the
environment,
tendency
to
bioaccumulate
in
plant
or
animal
tissues,
and
toxicity:
EPA's
Office
of
Solid
Waste
and
Office
of
Pollution
Prevention
and
Toxics
created
this
list
of
persistent,
bioaccumulative,
and
toxic
(
PBT)
chemicals.
PBT
chemicals
do
not
readily
break
down
or
decrease
in
potency
after
they
are
released
into
the
environment,
even
if
released
in
quantities
that
are
very
small
and
legally
permitted.
Over
time,
these
chemicals
are
likely
to
accumulate
in
soils
or
other
environmental
media,
be
absorbed
or
ingested
by
animals
and
plants,
accumulate
in
animal
and
plant
tissue,
pass
through
the
food
chain,
and
potentially
cause
long­
term
human
health
or
ecological
problems.
°
Priority
pesticides
of
potential
concern:
We
combined
two
lists
of
potentially
harmful
chemicals
to
develop
this
list.
EPA's
Office
of
Pesticides
Programs
provided
a
list
of
pesticides
of
concern
that
were
classified
as
organophosphates;
carbamates;
or
group
B1,
B2,
or
C
carcinogens.
According
to
a
program
official,
these
classes
of
pesticides
are
generally
considered
among
the
most
potentially
harmful
to
human
health.
We
combined
this
list
with
the
U.
S.
Department
of
Agriculture's
Pesticide
Data
Program
list
of
pesticides
that
are
measured
in
selected
commodities
or
foods.
Pesticides
monitored
by
the
program
in
1997
included
insecticides,
herbicides,
fungicides,
and
growth
regulators
in
fresh
and
processed
fruit
and
vegetables,
whole
milk,
and
grains.
°
Chemicals
that
are
known
or
probable
carcinogens:
HHS'
Report
on
Carcinogens
includes
substances
known
or
reasonably
thought
to
be
cancer­
causing
based
on
evaluations
of
substances
performed
by
scientists
from
NTP,
other
federal
health
research
and
regulatory
agencies,
and
nongovernment
institutions.
The
list
of
substances
in
the
report
represents
an
initial
step
in
hazard
identification.
Substances
listed
as
"
known
to
be
human
carcinogens"
are
those
for
which
there
is
sufficient
evidence
of
carcinogenicity
(
cancer­
causing
potential)
in
Appendix
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Scope,
and
Methodology
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humans
to
indicate
a
causal
relationship
between
exposure
to
the
agent,
substance,
or
mixture
and
human
cancer.
Substances
listed
as
"
reasonably
anticipated
to
be
human
carcinogens''
are
those
for
which
there
is
limited
evidence
of
carcinogenicity
in
humans,
insufficient
evidence
of
carcinogenicity
in
experimental
animals,
or
both.
°
Chemicals
that
are
considered
toxic
and
used,
manufactured,
treated,
transported,
or
released
into
the
environment:
EPA
publishes
the
Toxics
Release
Inventory
containing
information
on
the
release
and
other
waste
management
activities
of
toxic
chemicals
by
facilities
that
manufacture,
process,
or
otherwise
use
them.
This
database
is
made
available
to
the
public
and
is
considered
useful
to
citizens,
businesses,
and
governments
for
purposes
of
working
together
to
protect
the
quality
of
their
land,
air,
and
water
and
for
evaluating
the
probability
that
chemical
releases
could
impact
human
health
in
communities.
°
Chemicals
most
in
need
of
testing
required
by
the
Toxic
Substances
Control
Act:
The
Master
Testing
list
contains
those
chemicals
that
are
prioritized
for
safety
testing
based
on
EPA's
finding
that
(
1)
a
chemical
may
present
an
unreasonable
risk
of
injury
to
human
health
or
the
environment
and/
or
the
chemical
is
produced
in
substantial
quantities
that
could
result
in
significant
or
substantial
human
or
environmental
exposure,
(
2)
the
available
data
to
evaluate
the
chemical
are
inadequate,
and
(
3)
testing
is
needed
to
develop
the
required
data.

We
compared
the
combined
list
of
these
chemicals,
totaling
1,456,
and
each
individual
list
with
those
chemicals
identified
by
EPA
and
CDC
officials
as
measured
in
the
NHEXAS
and
NHANES
human
exposure
efforts
through
2000.
We
excluded
NHATS'
and
the
Human
Exposure
Initiative's
chemical
lists
from
our
analysis.
NRC's
1991
review
of
the
NHATS
program
raised
questions
about,
for
example,
the
representativeness
of
the
results
and
the
methods
used
to
handle
the
tissue
specimens.
NIEHS'
Human
Exposure
Initiative
measurements
were
not
complete
at
the
time
of
our
review
and
thus
it
was
not
known
which
chemicals
had
been
or
are
currently
being
measured.

Survey
Development
and
Distribution
and
Analysis
To
develop
survey
questions,
we
reviewed
documentation
on
environmental
health
programs
prepared
by
HHS
and
EPA
agencies,
professional
organizations
representing
state
epidemiology
and
public
health
laboratory
officials,
and
public
health
experts.
We
also
spoke
with
officials
and
representatives
from
each
of
these
groups.
Appendix
I
Objectives,
Scope,
and
Methodology
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We
pretested
our
survey
in
person
with
state
environmental
health
officials
in
two
states
and
in
teleconferences
with
officials
in
two
additional
states.
We
asked
knowledgeable
people
in
EPA
and
CDC
and
in
the
environmental
and
public
health
fields
to
review
the
survey
instrument.
We
refined
the
questionnaire
in
response
to
their
comments
to
help
ensure
that
potential
respondents
could
provide
the
information
requested
and
that
our
questions
were
fair,
relevant,
answerable
with
readily
available
information,
and
relatively
free
of
design
flaws
that
could
introduce
bias
or
error
into
our
study
results.
We
mailed
questionnaires
to
the
93
officials
in
August
1999.
We
sent
at
least
one
follow­
up
mailing
and
conducted
telephone
follow­
ups
to
nonrespondents.
We
ended
data
collection
in
December
1999;
had
received
responses
from
81
officials
in
48
states
for
a
response
rate
of
87
percent.

In
preparing
for
our
analysis,
we
reviewed
and
edited
the
completed
questionnaires
and
checked
the
data
for
consistency.
We
tested
the
validity
of
the
respondents'
answers
and
comments
by
comparing
them
with
data
we
gathered
through
interviews
with
public
health
experts
and
other
public
health
officials
and
with
documentation
obtained
at
federal
agencies
and
in
case
study
states.

The
survey
and
survey
results
are
presented
in
appendix
III.
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80
Environmental
Health
Data
Needs
Appendix
II
Reported
Gaps
in
Human
Exposure
Data
and
History
of
Federal
Efforts
AppendixII
Since
the
1980s,
reports
reviewing
environmental
health
data
needs
have
recommended
the
broader
collection
of
human
data
showing
actual
human
exposures
to
chemical
contaminants
in
the
environment.
Various
federal
agencies
have
collected
such
human
exposure
data
for
a
number
of
purposes;
historically,
these
collection
efforts
have
been
limited
to
selected
chemicals,
subpopulations,
and
time
periods.

Various
Reports
Discuss
the
Gaps
in
Human
Data
Showing
Measured
Exposure
to
Chemical
Contaminants
Data
on
actual
levels
of
chemicals
in
humans
has
been
a
longstanding
gap
in
the
information
needed
to
establish
human
health
risks
from
exposures
to
environmental
contaminants.
While
data
on
the
concentration
of
chemicals
in
environmental
media
 
such
as
air,
water,
and
food
 
have
historically
been
used
to
estimate
human
exposure
to
harmful
chemicals,
this
approach
to
detect
or
define
human
health
risks
has
limitations.
According
to
the
NRC,
there
are
too
many
chemicals,
too
many
sources,
and
too
many
routes
of
exposure
to
rely
solely
on
environmental
monitoring.
Measurements
of
internal
doses
of
exposure
 
actual
levels
of
chemicals
or
their
metabolites
found
in
human
tissues,
such
as
blood
or
urine
 
are
generally
considered
an
accurate
measure
of
human
exposure.
Such
measurements
can
reflect
exposures
from
all
routes
and
that
may
be
accumulated
over
time,
modified
by
individual
differences
in
physiology,
and
difficult
or
impossible
to
assess
by
environmental
measurements
(
such
as
hand­
to­
mouth
ingestion
in
young
children).
In
1991,
NRC
reported
that
a
program
of
human
tissue
monitoring
is
critical
to
the
continued
improvement
of
understanding
of
exposure
to
toxic
chemicals
and
recommended
that
such
a
program
be
given
high
priority
for
funds
and
other
resources.
1
Several
other
federal
reviews
have
pointed
to
information
needs
in
this
area.
An
interagency
assessment
of
federally
supported
databases
conducted
in
the
early
1990s
concluded
that
federal
data
systems
generally
lacked
data
on
actual
human
exposures,
including
information
about
contact
between
the
chemical
and
the
human
body
(
personal
exposures)
and
the
amount
of
the
chemical
absorbed
(
internal
doses).
The
review
also
found
substantial
value
in
collecting
and
analyzing
these
data
in
a
comprehensive
and
systematic
manner
and
that
the
costs
associated
with
1NRC,
Commission
on
Life
Sciences,
Monitoring
Human
Tissues
for
Toxic
Substances.
Appendix
II
Reported
Gaps
in
Human
Exposure
Data
and
History
of
Federal
Efforts
Page
53
GAO/
HEHS­
00­
80
Environmental
Health
Data
Needs
establishing
and
maintaining
appropriate
databases
were
justified.
2
A
discussion
of
some
of
these
reviews
follow.

°
HHS,
NCHS,
Environmental
Health:
A
Plan
for
Collecting
and
Coordinating
Statistical
and
Epidemiologic
Data(
Washington,
D.
C.:
Government
Printing
Office,
1980):
This
report
found
that
"
acceptable
ranges
of
physiologic
measurements
and
normal
levels
of
trace
elements
must
be
determined
before
any
attempt
can
be
made
to
associate
health
outcomes
with
environmental
exposures.
Many
of
these
baseline
data
do
not
exist
for
particular
populations
of
interest
or
for
specific
pollutants.
In
addition,
early
indicators
and
symptoms
of
disease
that
might
be
environmentally
related
are
not
clearly
understood."
The
report
identified
a
number
of
research
directions
to
help
define
the
association
between
health
effects
and
specific
environmental
exposures,
including
the
establishment
of
baseline
data
on
physiological
measurements
of
trace
elements
in
tissue
and
blood
for
the
population.
°
HHS,
NIEHS,
Issues
and
Challenges
in
Environmental
Health
(
Washington,
D.
C.:
National
Institutes
of
Environmental
Sciences,
1987):
This
report
found
that
due
to
"
gaps
in
data
systems
established
for
monitoring
and
surveillance
of
environmental
exposure,
effort
should
be
made
to
foster
better
linkage
among
existing
systems.
.
.
.
Existing
data
systems
should
be
expanded
to
include
biochemical
and
cellular
indicators
of
early
stages
of
disease.
.
.
.
The
group
found
there
is
a
need
for
more
research
and
more
systematic
collection
of
data
on
the
exposure
of
human
populations
to
harmful
substances.
Reliable
exposure
data
are
necessary
for
assessing
the
probability
that
exposed
populations
will
develop
adverse
health
effects
and
the
likelihood
of
success
in
intervening
to
reduce
those
risks."
°
K.
Sexton
and
others,
"
Estimating
Human
Exposures
to
Environmental
Pollutants:
Availability
and
Utility
of
Existing
Databases":
This
report
found
that
while
"
the
evidence
suggests
that
existing
data
systems
contain
a
substantial
amount
of
information
that
is
relevant
to
exposure
estimation
.
.
.
the
quality
of
the
data
is
inconsistent
and
difficult
to
assess
and
that
understanding
and
accessing
the
information
is
often
difficult.
Furthermore,
these
systems
demonstrate
a
striking
absence
of
data
on
actual
human
exposures,
including
a
lack
of
information
about
2See
K.
Sexton
and
others,
"
Estimating
Human
Exposures
to
Environmental
Pollutants:
Availability
and
Utility
of
Existing
Databases,"
Archives
of
Environmental
Health,
Vol.
47,
No.
6
(
1992),
pp.
398­
407.
Appendix
II
Reported
Gaps
in
Human
Exposure
Data
and
History
of
Federal
Efforts
Page
54
GAO/
HEHS­
00­
80
Environmental
Health
Data
Needs
contact
between
the
agent
and
the
human
body
(
exposure)
and
about
the
amount
of
the
agent
or
its
metabolites
that
enters
the
body
(
dose)."
°
NRC,
Hormonally
Active
Agents
in
the
Environment:
This
report
found
that
"
determining
the
risk
of
environmental
hormonally
active
agents
to
humans
and
wildlife
is
difficult
because
exposure
to
these
agents
has
not
been
routinelymonitored
.
.
.
.
Background
concentrations
of
hormonally
active
agents
in
humans,
particularly
in
adipose
(
fat)
tissue
and
blood,
and
other
biota
need
to
be
established.
In
particular,
routes
of
exposure
and
the
effects
of
diet
need
to
be
assessed
to
provide
a
framework
for
examining
the
effects
of
these
compounds
in
the
general
population
and
in
highly­
exposed
subpopulations."

History
of
Federal
Efforts
to
Collect
Human
Exposure
Data
Since
1967,
HHS
and
EPA
have
conducted
federal
surveys
to
assess
the
U.
S.
population's
exposures
to
toxic
chemicals
from
the
analysis
of
human
tissue
samples.
While
their
efforts
measured
some
of
the
same
exposures
and
covered
some
of
the
same
time
periods,
their
goals
differed
and
most
did
not
include
a
nationally
representative
sample
of
citizens.
EPA's
efforts
first
monitored
exposure
to
pesticides
and,
more
recently,
have
attempted
to
link
human
exposure
data
to
specific
routes
of
exposure.
CDC's
periodic
surveys
are
intended
to
monitor
trends
in
the
health
and
nutrition
status
of
the
population
but,
over
time,
have
included
exposures
to
environmental
toxics
as
one
component
of
the
general
survey.
NIEHS'
Human
Exposure
Initiative,
established
in
the
late
1990s,
is
intended
to
help
the
agency
prioritize
chemicals
for
further
toxicology
and
carcinogenicity
testing.
Within
these
studies,
various
subgroups
have
been
used
to
develop
human
exposure
estimates,
but
in
most
cases,
sampling
has
not
been
for
all
participant
groups
or
random.
Consequently,
the
results
cannot
be
projected
to
the
U.
S.
population
as
a
whole
for
most
chemicals.
See
table
5
for
the
time
frames
and
numbers
of
chemicals
covered
for
major
federal
efforts.
Appendix
II
Reported
Gaps
in
Human
Exposure
Data
and
History
of
Federal
Efforts
Page
55
GAO/
HEHS­
00­
80
Environmental
Health
Data
Needs
Table
5:
Number
of
Chemicals
and
Time
Frames
for
Select
Federal
Efforts
aThe
number
of
participants
in
NHANES
II
and
NHANES
III
who
received
physical
examinations
is
used
as
a
proxy
for
the
number
providing
biological
samples,
as
the
latter
number
was
not
readily
available.

bThe
number
of
persons
examined
in
a
calendar
year
is
planned
to
be
about
5,000.

cFor
NHANES,
the
list
of
potentially
toxic
chemicals
covered
was
provided
by
CDC
laboratory
officials.
For
NHEXAS,
the
list
of
potentially
toxic
chemicals
covered
was
provided
by
EPA
NHEXAS
officials.

dAccording
to
a
CDC
laboratory
official,
lead
and
cadmium
are
measured
in
all
participants.
Cotinine
will
also
be
measured
in
many
participants
 
specifically,
those
ages
4
and
older.

eChemicals
analyzed
by
NHATS
varied
over
time.
NHATS
collected
data
on
20
pesticides
between
1970
and
1981.
NIEHS
chemicals
are
not
included
because
data
were
not
available
at
the
time
of
our
review.

fExcludes
a
related
but
separate
study
done
in
Minnesota
reviewing
pesticide
exposures
that
was
not
one
of
the
three
formal
pilot
surveys.

A
description
of
these
federal
efforts
to
collect
human
exposure
data
follows.

°
CDC's
National
Health
and
Nutrition
Examination
Surveys:
NHANES,
conducted
multiple
times
since
1960
by
NCHS,
is
designed
to
provide
national
estimates
of
the
health
and
nutrition
status
of
the
noninstitutionalized
civilian
population
of
the
United
States.
Estimates
are
obtained
by
examining
randomly
selected
participants
in
a
manner
that
accurately
reflects
the
demographic
characteristics
of
the
U.
S.
population.
Participants
are
given
comprehensive
physical
examinations
(
including
tissue
samples)
and
are
interviewed
on
issues
Duration
Number
of
participants
providing
biological
samples
Number
of
chemicals
measured
for
any
participants
Number
of
chemicals
measured
for
all
participants
(
ages
1
and
older)

Second
National
Health
and
Nutrition
Examination
Survey
(
NHANES
II)

1976­
1980
20,000
examineda
36
1
Third
National
Health
and
Nutrition
Examination
Survey
(
NHANES
III)

1988­
1994
30,000
examineda
47
1
National
Health
and
Nutrition
Examination
Survey,
1999
(
NHANES)

1999­
ongoing
5,000
per
yearb
74c
2d
National
Human
Adipose
Tissue
Survey
(
NHATS)

1967­
1992
14,000
128
20e
National
Human
Exposure
Assessment
Survey
(
NHEXAS)
Pilot
Study
1995­
1999
460f
46c
6
Appendix
II
Reported
Gaps
in
Human
Exposure
Data
and
History
of
Federal
Efforts
Page
56
GAO/
HEHS­
00­
80
Environmental
Health
Data
Needs
such
as
their
nutritional
habits,
health
conditions,
and
housing
characteristics.
NHANES
data
are
used
for
a
number
of
purposes.
For
example,
in
addition
to
monitoring
changes
in
blood
lead
levels,
uses
of
NHANES
include
development
of
national
standards
for
blood
pressure
and
cholesterol
levels
and
for
determining
infection
rates
for
diseases.
CDC's
laboratory
housed
at
NCEH
performs
the
measurements
of
chemicals
in
human
tissues
for
NHANES.
°
Second
National
Health
and
Nutrition
Examination
Survey:
NHANES
II
was
designed
to
provide
national
estimates
of
the
health
and
nutritional
status
of
the
civilian
noninstitutionalized
population
of
the
United
States
for
persons
aged
6
months
to
74
years.
Children,
the
elderly
and
people
classified
as
living
at
or
below
the
poverty
level
were
oversampled
in
order
to
increase
the
reliability
of
the
estimates
for
these
groups.
Measurements
of
pesticide
residues
were
taken
from
participants
who
were
between
the
ages
of
12
and
74
years
of
age.
3
Blood
lead
measurements
were
taken
from
participants
in
all
age
groups
in
the
survey.
°
Third
National
Health
and
Nutrition
Examination
Survey:
NHANES
III
was
designed
to
provide
national
estimates
of
health
and
nutritional
status
of
the
civilian
noninstitutionalized
population
of
the
United
States
ages
2
months
and
older.
Children
ages
2
months
through
5
years,
blacks,
Mexican­
Americans,
and
persons
ages
60
or
older
were
oversampled
to
increase
the
reliability
of
the
estimates
for
these
groups.
Blood
lead
measurements
were
taken
from
all
participants
ages
1
year
or
older.
Cadmium
measurements
were
taken
from
all
participants
ages
6
years
or
older.
In
addition,
some
participants
ages
20
through
59
years
hadmeasurements
taken
for
volatile
organic
compounds
and
pesticides.
Participants
volunteered
for
these
additional
measurements,
so
the
results
cannot
be
projected
to
the
population
as
a
whole.
However,
the
results
still
serve
as
the
reference
ranges
for
these
chemicals.
°
National
Health
and
Nutrition
Examination
Survey,
1999:
In
1999,
NCHS
changed
the
design
of
NHANES
so
that
it
will
now
be
conducted
as
a
continuous
survey
of
about
5,000
participants
annually.
Like
the
previous
surveys,
NHANES
will
yield
nationally
representative
results
for
the
civilian
noninstitutionalized
population.
The
NHANES
design
will
allow
for
oversampling
to
vary
between
years;
persons
aged
12
to
19,
persons
aged
60
and
over,
blacks,
and
Mexican­
Americans
are
being
oversampled.
It
will
be
tied
to
related
federal
government
data
3Data
were
not
publicly
available,
as
CDC
is
resolving
some
methodological
issues
associated
with
data
collection.
Appendix
II
Reported
Gaps
in
Human
Exposure
Data
and
History
of
Federal
Efforts
Page
57
GAO/
HEHS­
00­
80
Environmental
Health
Data
Needs
collections
conducted
on
the
general
U.
S.
population,
in
particular,
the
National
Health
Interview
Survey.
4
NCHS
also
plans
to
release
results
from
the
survey
every
year
after
the
first
3
years
of
data
collection.
More
than
1
year
of
data
will
be
required
for
many
estimates,
particularly
among
detailed
subgroups
of
the
population.
While
lead
and
cadmium
will
be
the
only
potentially
toxic
chemicals
measured
for
all
participants
ages
1
and
older
(
although
cotinine,
a
metabolite
which
illustrates
exposure
to
environmental
tobacco
smoke,
will
be
measured
for
most
age
groups
 
those
ages
4
and
over),
NCHS
and
NCEH
plan
to
get
nationally
representative
data
for
specific
chemicals
for
persons
in
specific
demographic
groups,
such
as
mercury
measurements
in
women
ages
16
through
49.
NCHS
will
also
measure
household
lead
dust,
drinking
water
contaminants,
and
exposure
to
volatile
organic
compounds
for
selected
participants.
In
addition
to
conducting
an
annual
national
survey,
NCHS
is
developing
a
smaller,
more
targeted
health
survey
 
the
Defined
Population
Health
and
Nutrition
Examination
Survey
(
DP­
HANES).
NCHS
recognizes
that
NHANES
cannot
collect
information
that
would
be
directly
useful
at
the
local
or
state
level
or
for
small
populations.
DP­
HANES
is
intended
to
address
this
issue
through
the
use
of
small
mobile
examination
centers
that
would
visit
areas
of
interest
and
examine
2,000
to
3,000
participants
for
each
special
study.
DP­
HANES
participants
would
not
receive
the
full
range
of
tests
given
under
NHANES;
rather,
the
DP­
HANES
examination
would
be
tailored
to
the
specific
needs
of
the
population
under
study.
°
EPA's
National
Human
Adipose
Tissue
Survey:
NHATS
was
intended
to
be
a
continuously
operating
survey
that
would
collect,
store,
and
analyze
samples
of
autopsy
and
surgical
specimens
of
human
adipose
tissue
from
major
metropolitan
areas
of
the
country.
It
was
established
by
HHS
in
1967
and
was
transferred
to
EPA
in
1970.
During
its
existence,
NHATS
data
documented
the
widespread
and
significant
prevalence
of
pesticide
exposures
in
the
general
population.
NHATS
data
also
showed
that
reduced
use
of
polychlorinated
biphenyls
(
PCB)
and
DDT
and
dieldrin
(
common
insecticides)
resulted
in
lower
tissue
concentrations
of
these
compounds.
A
trend
analysis
for
1970
through
1981
of
NHATS
data
showed
a
dramatic
decline
in
PCB
concentrations
after
the
regulation
of
PCBs
in
1976.
During
the
1980s,
problems
with
NHATS'
survey
design,
management,
and
goals
were
compounded
by
insufficient
financial
support
and
caused
the
usefulness
and
quality
of
NHATS
to
4The
sampling
will
be
conducted
on
different
people,
but
some
questions
asked
in
each
survey
will
be
the
same.
Appendix
II
Reported
Gaps
in
Human
Exposure
Data
and
History
of
Federal
Efforts
Page
58
GAO/
HEHS­
00­
80
Environmental
Health
Data
Needs
deteriorate.
In
1991,
NRC
conducted
a
study
to
review
and
evaluate
the
effectiveness
and
potential
applications
of
NHATS.
5
The
study
concluded
that
a
more
comprehensive
national
program
of
human
tissue
monitoring
was
a
critical
need
for
understanding
human
exposures
to
environmental
toxics.
In
addition,
EPA
needed
a
human
tissue
monitoring
program
in
order
to
evaluate
the
need
and
effectiveness
of
EPA's
regulatory
programs.
The
study
recommended
that
NHATS
be
completely
redesigned
to
provide
more
useful
data
based
on
probability
samples
of
the
whole
U.
S.
population
and
that
funding
be
increased
to
permit
the
program
to
fulfill
its
mission.
EPA
ended
the
NHATS
in
1992
and
replaced
it
with
the
NHEXAS
pilot
surveys.
°
EPA's
National
Human
Exposure
Assessment
Survey
Pilot
Surveys:
The
NHEXAS
pilot
surveys
were
designed
to
obtain
knowledge
on
the
multiple
pathways
and
media
population
distribution
of
exposures
to
several
classes
of
chemicals
and
to
test
the
feasibility
of
conducting
a
national
survey
to
provide
estimates
on
the
status
of
human
exposure
to
potentially
high­
risk
chemicals.
NHEXAS
was
also
designed
to
measure
"
total
exposure"
 
the
levels
of
chemicals
participants
take
in
through
the
air
they
breathe;
the
food,
drinking
water,
and
other
beverages
they
consume;
and
in
the
soil
and
dust
around
their
homes.
Measurements
have
also
been
made
of
chemicals
in
biological
samples
(
such
as
blood
and
urine)
provided
by
some
participants.
Participants
completed
questionnaires
to
help
identify
possible
sources
of
exposure
to
chemicals.
As
designed,
NHEXAS
has
three
phases.
Phase
I
is
intended
to
develop
and
validate
NHEXAS
methods,
phase
II
is
designed
to
obtain
nationally
representative
exposure
data
in
a
manner
similar
to
that
used
by
NHANES
to
get
health
data,
and
phase
III
is
designed
to
follow
up
on
information
developed
from
phase
II
and
will
study
selected
subpopulations.
EPA
conducted
NHEXAS
phase
I
(
pilot)
surveys
in
Arizona,
Maryland,
and
EPA's
region
5
(
Illinois,
Indiana,
Michigan,
Minnesota,
Ohio,
and
Wisconsin).
About
460
participants
in
the
pilot
surveys
provided
biological
samples;
examinations
measured
a
variety
of
chemicals,
such
as
volatile
organic
compounds,
heavy
metals,
and
pesticides.
Human
tissue
measurements
were
performed
under
interagency
agreement
by
CDC's
environmental
health
laboratory.
EPA
has
completed
most
of
the
fieldwork
for
the
NHEXAS
phase
I
surveys
and
is
now
analyzing
the
results.
Based
on
these
results,
EPA
will
finalize
the
scope
and
methods
for
NHEXAS
phases
II
and
III.

5NRC,
Commission
on
Life
Sciences,
Monitoring
Human
Tissues
for
Toxic
Substances.
Appendix
II
Reported
Gaps
in
Human
Exposure
Data
and
History
of
Federal
Efforts
Page
59
GAO/
HEHS­
00­
80
Environmental
Health
Data
Needs
°
ATSDR's
Exposure
Investigations:
As
part
of
its
health
assessment
process
or
in
response
to
requests,
ATSDR
may
conduct
limited
biological
monitoring
at
hazardous
waste
sites
or
other
locations
through
a
process
called
exposure
investigations.
In
response
to
the
recognition
that
the
conclusions
drawn
from
indirect
methods
of
measuring
exposures
were
often
not
accurate
and
not
reliable
for
assessing
potential
health
impacts
and
the
need
for
more
direct
measures
of
exposures,
ATSDR
formally
established
an
exposure
investigation
unit
within
its
Division
of
Health
Assessments
and
Consultation.
The
Exposure
Investigation
Section
was
established
in
1995
and
is
comprised
of
nine
staff
members
who
respond
to
requests
to
conduct
exposure
investigations
around
hazardous
waste
sites.
These
investigations
involve
gathering
biological
samples,
conducting
personal
monitoring
for
site­
related
contaminants
and
their
byproducts,
and
analyzing
environmental
data
using
computational
tools.

In
1996,
ATSDR
convened
an
expert
review
panel
to
comment
on
ATSDR's
exposure
investigation
program,
including
whether
ATSDR
was
on
the
right
track
in
providing
exposure
information
to
improve
public
health
decisionmaking
intended
to
address
environmental
releases
from
hazardous
waste
sites.
The
panelists
endorsed
many
aspects
of
ATSDR's
investigative
process,
including
the
following:

°
Conducting
exposure
investigations
prior
to
preparing
public
health
assessments,
which
makes
agency
responsibilities
easier
because
information
is
provided
that
enables
federal
agencies
to
take
action
and
respond
to
community
concerns
in
a
timely
manner.
°
Considering
exposure
determinations
to
be
as
important
as
obtaining
environmental
monitoring
results.
°
Emphasizing
the
human
element
of
exposure
investigations,
which
illustrates
that
the
federal
government
responds
to
community
concerns.

The
panel
also
made
several
suggested
improvements
to
the
process,
including
establishing
a
national
clearinghouse
of
exposure
investigation
data
and
results
and
developing
site
criteria
and
a
protocol
for
identifying
who
will
decide
on
sites
to
target
for
exposure
investigation.

ATSDR's
exposure
investigations
have
been
valuable
but
limited
in
scope.
ATSDR
used
biological
monitoring
in
conducting
47
exposure
investigations
between
1995
and
July
1999.
Of
these
investigations,
17
Appendix
II
Reported
Gaps
in
Human
Exposure
Data
and
History
of
Federal
Efforts
Page
60
GAO/
HEHS­
00­
80
Environmental
Health
Data
Needs
were
done
in
support
of
the
460
health
assessments
done
at
that
time.
Unlike
NHANES
and
the
NHEXAS
pilot
surveys,
exposure
investigations
usually
have
a
small
number
of
participants
(
less
than
100)
who
volunteer
to
participate
in
the
study.
While
the
exposure
investigations
are
not
intended
to
be
used
for
generalizations
about
larger
populations,
the
studies
have
proven
very
useful
in
ATSDR's
community
outreach
and
intervention
activities.

°
NIEHS'
Human
Exposure
Initiative:
In
1996,
this
initiative,
a
collaboration
between
NIEHS
and
CDC,
was
started
to
improve
understanding
of
human
exposures
to
hormonally
active
agents
 
also
called
"
environmental
endocrine
disrupters"
 
for
the
national
population.
CDC's
environmental
health
laboratory
under
an
interagency
agreement
is
developing
methods
for
and
measuring
up
to
80
chemicals
thought
to
be
hormonally
active
agents
in
blood,
urine,
or
both.
Human
tissue
samples
used
for
these
measurements
are
largely
obtained
from
the
ongoing
sampling
of
the
general
population
under
NHANES
and
total
about
200
in
number.

In
1999,
NIEHS
and
NTP
officials
proposed
to
expand
the
initial
collaboration
between
NIEHS
and
CDC
by
quantifying
human
internal
exposures
to
selected
chemicals
that
are
released
into
the
environment
and
workplace.
NTP
officials
indicated
this
information
would
benefit
public
health
and
priority­
setting
in
a
number
of
ways.
First,
it
would
strengthen
the
scientific
foundation
for
risk
assessments
by
allowing
(
1)
the
development
of
more
credible
relationships
between
exposure
and
response
in
people
thereby
improving
cross­
species
extrapolation,
(
2)
the
development
of
biologically
based
dose­
response
models,
and
(
3)
the
identification
of
sensitive
subpopulations
and
for
estimates
of
risk
based
on
"
margin
of
exposure."
Second,
it
would
provide
the
kind
of
information
necessary
for
deciding
which
chemicals
should
be
studied
with
the
limited
resources
available
for
toxicological
testing.
For
example,
there
are
85,000
chemicals
in
commerce
today,
and
NTP
can
provide
toxicological
evaluations
on
10
to
20
per
year.
Third,
the
information
could
be
used
to
identify
and
help
focus
research
on
those
mixtures
of
chemicals
that
are
actually
present
in
people's
bodies.
Fourth,
the
types
and
amount
of
chemicals
in
children
and
other
potentially
sensitive
subpopulations
would
be
identified.
Determinations
of
whether
additional
safety
factors
need
to
be
applied
to
children
must
rest
in
part
upon
comparative
exposure
analyses
between
children
and
adults.
Fifth,
this
initiative,
taken
together
with
the
environmental
genome
initiative,
will
provide
the
science
base
Appendix
II
Reported
Gaps
in
Human
Exposure
Data
and
History
of
Federal
Efforts
Page
61
GAO/
HEHS­
00­
80
Environmental
Health
Data
Needs
essential
for
meaningful
studies
on
gene
and
environment
interactions,
particularly
for
strengthening
the
evaluation
of
epidemiology
studies.
Finally,
efficacy
of
public
health
policies
aimed
at
reducing
human
exposure
to
chemical
agents
could
be
evaluated
in
a
more
meaningful
way
if
human
exposure
data
were
available
over
time,
including
remediation
around
Superfund
sites
and
efforts
to
achieve
environmental
equity.
Page
62
GAO/
HEHS­
00­
80
Environmental
Health
Data
Needs
Appendix
III
Survey
of
State
Environmental
Health
Officials
and
Results
AppendixII
Appendix
III
Survey
of
State
Environmental
Health
Officials
and
Results
Page
63
GAO/
HEHS­
00­
80
Environmental
Health
Data
Needs
Appendix
III
Survey
of
State
Environmental
Health
Officials
and
Results
Page
64
GAO/
HEHS­
00­
80
Environmental
Health
Data
Needs
Appendix
III
Survey
of
State
Environmental
Health
Officials
and
Results
Page
65
GAO/
HEHS­
00­
80
Environmental
Health
Data
Needs
Appendix
III
Survey
of
State
Environmental
Health
Officials
and
Results
Page
66
GAO/
HEHS­
00­
80
Environmental
Health
Data
Needs
Appendix
III
Survey
of
State
Environmental
Health
Officials
and
Results
Page
67
GAO/
HEHS­
00­
80
Environmental
Health
Data
Needs
Page
68
GAO/
HEHS­
00­
80
Environmental
Health
Data
Needs
Appendix
IV
Comments
From
the
Department
of
Health
and
Human
Services
AppendixIV
Appendix
IV
Comments
From
the
Department
of
Health
and
Human
Services
Page
69
GAO/
HEHS­
00­
80
Environmental
Health
Data
Needs
Appendix
IV
Comments
From
the
Department
of
Health
and
Human
Services
Page
70
GAO/
HEHS­
00­
80
Environmental
Health
Data
Needs
Appendix
IV
Comments
From
the
Department
of
Health
and
Human
Services
Page
71
GAO/
HEHS­
00­
80
Environmental
Health
Data
Needs
Appendix
IV
Comments
From
the
Department
of
Health
and
Human
Services
Page
72
GAO/
HEHS­
00­
80
Environmental
Health
Data
Needs
Page
73
GAO/
HEHS­
00­
80
Environmental
Health
Data
Needs
Appendix
V
Comments
From
the
Environmental
Protection
Agency
AppendixV
Now
on
page
6.

Now
on
page
41.
Appendix
V
Comments
From
the
Environmental
Protection
Agency
Page
74
GAO/
HEHS­
00­
80
Environmental
Health
Data
Needs
Appendix
V
Comments
From
the
Environmental
Protection
Agency
Page
75
GAO/
HEHS­
00­
80
Environmental
Health
Data
Needs
Appendix
V
Comments
From
the
Environmental
Protection
Agency
Page
76
GAO/
HEHS­
00­
80
Environmental
Health
Data
Needs
Now
on
page
5.

Now
on
page
7.

Now
on
page
31.

See
page
26.
Appendix
V
Comments
From
the
Environmental
Protection
Agency
Page
77
GAO/
HEHS­
00­
80
Environmental
Health
Data
Needs
Page
78
GAO/
HEHS­
00­
80
Environmental
Health
Data
Needs
Appendix
VI
Major
Contributors
to
This
Report
AppendixVI
GAO
Contact
Katherine
Iritani,
Evaluator­
in­
Charge,
(
206)
287­
4820
Staff
Acknowledgments
The
following
individuals
made
important
contributions
to
this
report:
Frank
Pasquier
served
as
Assistant
Director;
Cheryl
Williams,
Senior
Evaluator,
performed
the
literature
review,
assessed
barriers,
performed
state
site
visits,
and
 
along
with
Anita
Kay,
Intern
 
administered
the
survey
of
state
environmental
health
officials;
Tim
Clouse,
Evaluator
assessed
federal
efforts
and
evaluated
information
collected
for
identifying
at­
risk
populations;
Sharon
Silas,
Intern,
and
Evan
Stoll,
Technical
Analyst,
compiled
and
analyzed
the
lists
of
toxic
chemicals;
Sylvia
Shanks
served
as
attorney­
adviser,
and
Stan
Stenersen
guided
the
message
development
and
report
writing.

(
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