United States
Environmental Protection
Agency
Office of Health and
Environmental Assessment
Washington DC 20460
Research and Development
EPA/600/S8-91/042 July 1991
v/EPA Project Summary
Updated Health Effects
Assessment Documents
An updated series of Health Effects
Assessment (HEA) documents were pre-
pared by the Environmental Criteria and
Assessment Office, Cincinnati, OH, for
the Office of Emergency and Remedial
Response. These documents update 15
of the 1984 HEAs and are brief, sum-
mary assessments of potential adverse
health effects following either oral or
inhalation exposure for the purpose of
remedial actions.
This Project Summary was devel-
oped by EPA's Environmental Criteria
and Assessment Office, Cincinnati, OH,
to announce key findings of the research
project that Is fully documented in sepa-
rate reports (see Project Report order-
Ing Information at back).
Introduction
These reports summarize and evaluate
information relevant to a preliminary in-
terim assessment of adverse health ef-
fects associated with specific chemicals
and compounds. All estimates of accept-
able intakes and carcinogenic potency pre-
sented in this document should be
considered as preliminary and reflect lim-
ited resources allocated to this project.
Pertinent toxicologic and environmental
data were located through on-line litera-
ture searches of the TOXLINE, CANCER-
LINE and the CHEMFATE/DATALOG data
bases. Secondary sources of information
have also been relied upon in the prepara-
tion of these reports and represent large-
scale health assessment efforts that entail
extensive peer and Agency review.
Discussion
The intent in these assessments is to
suggest acceptable exposure levels when-
ever sufficient data were available. Val-
ues were not derived or larger uncertainty
factors were employed when the variable
data were limited in scope tending to
generate conservative (i.e., protective)
estimates. Nevertheless, the interim val-
ues presented reflect the relative degree
of hazard associated with exposure or
risk to the chemical(s) addressed.
Whenever possible, two categories of
values have been estimated for systemic
toxicants (toxicants for which cancer is not
the endpoint of concern). The first, RfDs
(formerly AIS—Acceptable Intake Sub-
chronic) or subchronic reference dose, is
an estimate of an exposure level that would
not be expected to cause adverse effects
when exposure occurs during a limited
time interval (i.e., for an interval that does
not constitute a significant portion of the
lifespan). This type of exposure estimate
has not been extensively used, or rigor-
ously defined, as previous risk assess-
ment efforts have been primarily directed
towards exposures from toxicants in ambi-
ent air or water where lifetime exposure is
assumed. Animal data used for RfDs esti-
mates generally include exposures with
durations of 30-90 days. Subchronic hu-
man data are rarely available. Reported
exposures are usually from chronic occu-
pational exposure situations or from re-
ports of acute accidental exposure. These
values are developed for both inhalation
(RfDsl) and oral (RfDso) exposures.
Printed on Recycled Paper
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The RfD (formerly AIC - Acceptable
Intake Chronic) is similar in concept and
addresses chronic exposure. It is an esti-
mate of an exposure level that would not
be expected to cause adverse effects when
exposure occurs for a significant portion of
the lifespan. The RfD is route-specific and
estimates acceptable exposure for either
oral (RfD0) or inhalation (RfD,) with the
implicit assumption that exposure by other
routes is insignificant.
Composite scores (CSs) for noncar-
cinogens have also been calculated where
data permitted. These values are used for
ranking reportable quantities.
For compounds for which there is suffi-
cient evidence of card nog enicity, RfDs and
RfD values are not derived. Since the
Agency's cancer policy assumes a pro-
cess that is not characterized by a thresh-
old, any exposure contributes an increment
of risk. Consequently, derivation of these
values would be inappropriate. For car-
cinogens, q,*s have been computed based
on oral and/or inhalation data if available.
The qt* represents an upper-bound esti-
mate on lifetime cancer risk as estimated
by the multi-stage model.
Inhalation values (RfDsl, RfD,, and q,*)
have been developed for purposes of in-
halation exposure evaluations only. These
values do not reflect differential absorption
assumptions appropriate for route-to-route
extrapolation. These estimates have been
developed to be readily transposable to
units of air concentration and have incor-
porated an assumption that exposure con-
centration will be relatively stable across a
24-hour period.
The primary locus of the brief literature
summaries presented in the HEAs is litera-
ture directly relevant to hazard assess-
ment, primarily mammalian toxicologic
evaluations of subchronic or chronic dura-
tion conducted utilizing oral or inhalation
exposure protocols. The HEAs generally
reflect secondary sources of information
when available in the form of more exten-
sive agency documentation.
Conclusion
Table 1 summarizes the risk as-
sessments developed in each docu-
ment. IMPORTANT REMINDER! These
assessments were prepared in 1988-
1989 and may have been superseded
by more recent documentation. Please
refer to the following references for the
most current information.
U.S. EPA Health Effects Assessment
Summary Table. Available from the
National Technical Information Ser-
vice, Springfield, VA, at 703/489-
4807. Order Number PB91-921100.
(This Table is updated quarterly, ev-
ery three months.)
U.S. EPA Integrated Risk Informa-
tion System (IRIS). Available online
from the National Library of
Medicine's Toxicology Data Network
(TOXNET) and from the National
Technical Information Service,
Springfield, VA, at 703/489-4807. Or-
der Number PB90-591330. (This data
base is updated quarterly, every three
months.)
Table 1. Summary of Risk Assessments
Chemical(s) RfDso RfD0
(mg/day) (mg/day)
Acetone
Benzene
Cadmium
Carbon Tetrachloride
Chlordane
Chlorobenzene
Chloroform
DDT
Methylene Chloride
Methyl Ethyl Ketone
Naphthalene
Phenol
Tetrachloroethylene
Trichloroethylene
Xylene
70
ND
NA
0.5*
ND
14
ND
ND
ND
32
29
42
ND
ND
250
7
ND
0.04
0.05'
ND
1.4
ND
ND
ND
3
29
42
ND
ND
126
RfDsl
(mg/day)
ID
ND
ND
ND
ND
3
ND
ND
ND
64
ID
ID
ND
ND
&>
RfD,
(mg/day)
ID
ND
ND
ND
ND
0.3
ND
ND
ND
6
ID
ID
ND
ND
6f
CS
6.5
ND
ND
ND
ND
8
ND
ND
ND
9.6
13.2
44
ND
ND
10
Q/*
(mg/kg/day) '
ID
2.9x10 *-oral
2.9x10 *-inhal.
6. 1-inhal.
1. 3x1 01 -oral
5.2x10 2-inhal.
1.3-oral
1.3-inhal.
ID
6.1x10*-oral
8.1x10 *-inhat.
0.34-oral
7.5x10 *-oral
1.4x10 *-inhal.
ID
ID
ID
5.1x10 '-oral
2.85x10 -> to
9.47x10 7-inhal.
1.1x10 '-oral
6x10 *-inhal.
ID
Cancer
Group
D
A
B1
B2
B2
D
B2
B2
B2
D
D
D
B2
B2
D
" = Calculated 0.3 mg/m3 x20 = 6 mg/day
ID - Insufficient Data
ND = Not Derived (Carcinogen)
NA = Not Applicable
&U.S. GOVERNMENT PRINTING OFFICE: IWI - 54«-OZ»/40032
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This Project Summary was prepared by staff of the Environmental Criteria and Assessment Office, USEPA,
Cincinnati, OH 45268.
Deb McKean is the EPA Project Officer, (see below).
This Project Summary covers 15 separate reports, entitiled, "Updated Health Effectrs Assessment for..."
Acetone (Order No. PB90-142373/AS; Cost $15.00)
Benzene (Order No. PB90-142381/AS; Cost $17.00)
Cadmium (Order No. PB90-142399/AS; Cost $17.00)
Carbon Tetrachloride (Order No. PB90-142407/AS; Cost $17.00)
Chlordane (Order No. PB90-142415/AS; Cost $15.00)
Chlorobenzene (OrderNo. PB90-142514/AS; Cost $15.00)
Chloroform (Order No. PB90-142423/AS; Cost $15.00)
DDT (Order No. PB90-142431/AS; Cost $17.00)
Methyl Ethyl Ketone (Order No. PB90-142456/AS; Cost $15.00)
Methylene Chloride (Order No. PB90-142449/AS; Cost $17.00)
Naphthalene (Order No. PB90-142464/AS; Cost $15.00)
Phenol (Order No. PB90-142472/AS; Cost $15.00)
Tetrachloroethylene (Order No. PB90-142480/AS; Cost $17.00)
Trichloroethylene (Order No. PB90-142498/AS; Cost $17.00)
Xylenes (Order No. PB90-142506/AS; Cost $17.00)
(All costs are subject to change)
The above reports will be available only from:
National Technical Information Service
5285 Port Royal Road
Springfield, VA 22161
Telephone: 703-487-4650
The EPA Project Officer can be contacted at:
Environmental Criteria and Assessment Office
U. S. Environmental Protection Agency
Cincinnati, OH 45268
United States
Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati, OH 45268
BULK RATE
POSTAGE & FEES PAID
EPA PERMIT NO. G-35
Official Business
Penalty for Private Use $300
EPA/600/S8-91/042
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