EPA/600/N-92/016
UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
Region II, New York, New York 10278
DATE: - October 22, 1992
SUBJECT: Risk Assessment Review
c<^&:—
FROM: William J. MrfszyTislsltf' P.E.
Deputy Regional Administrator
/-^
William Farland, Ph.D. / / /1V,
Director ^xK/^c (//C
Office of Health and Environmental Assessment
Attached is a copy of the Risk Assessment Review, a bimonthly
publication that is a cooperative effort between the Office
of Research and Development and the Regional Risk Assessment
Network.
The Review serves as a focal point for information exchange
among the EPA risk assessment community on both technical and
policy issues related to' risk assessment. It is currently in
its fourth year of publication and we are pleased at the
positive feedback we've received on the Review's usefulness
to staff across the Agency.
Thanks to all of you who continue to contribute articles and
are involved with production efforts. If you have an article
to contribute or any suggestions for further issues, contact
one of the Committee members listed on page 1 of the Review.
Attachment
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September 1992
Highlights
Office of Health and Environmental Assessment
Documents on Dioxin
Inhalation Slope Factors and Less-than-
Lifetime Exposure
....p. 1
....p. 1
Region X Report on Meeting on
"Equity in Environmental Health:
Research Issues and Needs"
Region X Risk-based Enforcement
Targeting Project
Ecological Risk Analysis of the
Mid-Snake River, Idaho
P. 3
P. 3
,.p.3
I. Special Features
Office of Health and Environmental
Assessment Documents on Dioxin
by Linda BaOtyBeeht (202) 260-7345
The Environmental Protection Agency recently held two
peer-review workshops to review draft documents on expo-
sure assessment procedures (September 10-11) and health
assessment issues (September 22-25) related to its reassess-
ment of dioxin. The health assessment chapters have been
printed as eight separate documents that will later be com-
Risk Assessment Review Committee
Bill Farland - ORD, (202) 260-7317
Maureen McClelland - Region I, (617) 565-4885
Maria Pavlova - Region II, (212) 264-7364
Marian Olsen - Region II, (212) 264-5682
Suzanne Wuerthele - Region Vm, (303) 293-1714
Dana Davoli - Region X, (206) 553-2135
bined into one health assessment document The draft docu-
ments, authored primarily by outside scientific experts, are
in a preliminary stage of development and do not represent
Agency policy. Comments received during the workshops
are being reviewed, and external review drafts will be
prepared and released for public review and comment,
followed by Science Advisory Board review.
Copies of the draft exposure document or any of the draft
health assessment chapters are available from the ORD
Publications Center, CERI, U.S. Environmental Protection
Agency, 26 West Martin Luther King Drive, Cincinnati,
Ohio 45268; telephone (513) 569-7562; FAX (513) 569-
7566. All requests should include name, mailing address,
and the appropriate document title and number from the list
on page 2.
J
II. Headquarters
Inhalation Slope Factors and Less-than-
Lifetime Exposure
by Charles Kit (202) 260-7338
At the Seventh Annual Regional Risk Assessor's Meeting
in Dallas, Texas, in June Charles Ris from the Office of
Health and Environmental Assessment (OHEA) in Wash-
ington, D.C., spoke on the following issues: additional
background information regarding the withdrawal of inha-
lation slope factors from IRIS, how to cope with assessment
procedures that are still geared to mg/kg/day units for
inhalation, and the latest thinking on less-than-lifetime
exposure and risk assessment The following information
paraphrases the slides and comments presented at the meet-
ing:
1. Use of mg/kg/day units for inhalation and oral slope
factors were in use without reservation until 1989.
Over the years, however, a number of technical and
procedural issues about using these units for inhalation
slope factors have evolved with similar experiences for
the reference concentrations (RfCs). In 1989, use of
mg/kg/day units for inhalation was discontinued and
only units of concentration are recommended and now
used. A number of concerns made the change war-
ranted. For example, the presence of two slope factors
in the same units was confusing the users, the dose
units of mg/kg and mg/kg/day were not always the unit
system of choice given the respiratory system effects
seen from inhalation exposure (ppm or dose per unit
respiratory surface area are generally better while the
systemic effects mg/kg/day may still be satisfactory), a
pharmacokinetic interface was more difficult to achieve,
mg/kg/day requires the assumption of respiratory rate
and body weight while concentration units do not
Concentration units are common units in monitoring
and exposure assessments. Since 1989, route extrapo-
lation between oral and inhalation or vice versa is only
done with justification and the availability of mg/kg/
day inhalation values tended to make such extrapola-
tion too easy an exercise. (When there is a justification
to convert from concentration units to mg/kg/day or
vice versa, 20 cubic meters per day is the nominal
adult 24-hour respiratory rate assumption, i.e., 1 mg/
kg/day = 3,500 micrograms/cubic meter). This is not to
say that pre-1989 mg/kg/day inhalation values were
incorrect, but their continued use warrants reflection.
(sec Inhalation p. 2)
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Office (continued from p. 1)
Estimating Exposures to Dioxin-Like Compounds
EPA/600/6-88/005B
Health Assessment Chapters
1. Disposition and Pharmacokinetics
EPA/600/AP-92/001a
2. Mechanisms of Toxic Actions
EPA/600/AP-92/001b
3. Acute, Subchronic and Chronic Toxicity
EPA/600/AP-92/001C
4. Inununotoxic Effects
EPA/600/AP-92/001d
5. Reproductive and Developmental Toxicity
EPA/600/AP-92/001e
6. Carcinogenicity of TCDD in Animals
EPA/600/AP-92/001f
7. Epidemiology/Human Data
EPA/600/AP-92/001g
8. Dose-Response Relationships
EPA/600/AP-92/001h
>• For questions on the exposure document, call John
Schaum, (202) 260-5988; FAX (202) 260-1722. For
questions on the health assessment call Bill Farlahd,
(202) 260-7315; FAX (202) 260-0393.
Inhalation (continued from p. 1)
In those cases where Agency procedures are set up to
use mg/kg/day for inhalation exposure, it is important
to realize that risk assessment science has moved ahead
and that Agency procedures are being updated to re-
flect these advances.
Participants at the Dallas meeting recommended that
some of the above information be inserted into the IRIS
Background Document file, and this will be done.
2. Update on the latest thinking about methods to ad-
dress less-than-lifetime or intermittent exposure in
cancer risk estimations. When exposures are intermit-
tent or last for less than lifetime, die cumulative expo-
sure received over a lifetime would generally be prorated
to obtain an average lifetime daily exposure. This is a
default assumption for use in the absence of informa-
tion indicating that such proration is unwarranted. For
example, if an individual were exposed to ambient air
containing 100 ppb for 20 hours per day, 300 days per
year, for 40 years, the average daily exposure would be
calculated as:
100 ppb x (20/24) x (300/365) x (40/70) = 39 ppb.
This approach becomes more problematic as the expo-
sures in question become more intense (i.e., when
evidence suggests that the agent has dose-rate effects)
and/or when exposure is less frequent "Average daily
exposure" refers to a prorated experience over an
individual's lifetime, not necessarily to a typical expe-
rience across a population. One could, for example,
calculate an average daily exposure for both a highly
exposed individual as well as for an individual near the
center of the exposure distribution.
3. Is the slope factor or unit risk still useful for less than
lifetime? Yes, up to a point The greater the departure
from continuous lifetime, the less the relative confi-
dence. In the past, the less-than-lifetime scenario has
been handled by using a default proration or modelled
adjustment factor, i.e., risk is proportional to total dose
over a 70 year lifetime so that 40 years of exposure is
40/70 of a lifetime. There are some circumstances
where pharmacokinetic modelling is more appropriate
for equivalent dose calculation as long as the model is
using chemical-specific parameters rather than a plethora
of assumptions. The less-than-lifetime issue puts even
more emphasis on the need to know, within reasonable
bounds of evidence, the mechanisms of action. (The
relationship among childhood-only, full-lifetime, and
adult-only exposure scenarios may be a sleeper issue).
In any case, when using the current EPA slope factors
or unit risks, the estimated upper bound cancer risk is
still at the end of the lifetime only because we don't yet
know how to do a partial lifetime slope factor or unit
risk.
in. Regions
Region II
ATSDR Study of Respiratory Effects from Waste
Burning Facilities in North Carolina
The Agency for Toxic Substances and Disease Registry
(ATSDR) is funding a three-year project to analyze air
quality and respiratory disease symptoms of residents near
two incinerators in North Carolina. The study will be con-
ducted by Dr. Carl Shy an epidemiologist with the Univer-
sity of North Carolina at Chapel HilL
> For additional information, contact Dr. Shy, (919) 966-
7448, or the project manager, Darrah Degnanat, (919)
966-7425.
Publications of Interest
• Health, United States, 1991. This report released by
the Centers for Disease Control's National Center for
Health Statistics, examines the health of and health
care for the nation and includes a chartbook section on
minority health, with detailed racial/ethnic data on
major health indicators. The report also provides data
on a wide range of health measures.
This volume includes the "1991 Prevention Profile."
The Prevention Profile examines the final status of the
1990 health objectives for the nation and highlights
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several components of the three broad national health
objectives for the year 2000.
Copies of "Health, United States, 1991" are available
from the Superintendent of Documents, U.S. Govern-
ment Printing Office, Washington, D.C. 20402; the
telephone number is (202) 783-3238. The stock num-
ber is 017-022-01156-5, and the price is $18.00.
• Annual Summary of Births, Marriages, Divorces
and Deaths: United States, 1991. The Centers for
Disease Control's National Center for Health Statistics
has released vital statistics (provisional data on the
number and rate of births, marriages, divorces, and
deaths) for 1991. The report presents statistics on the
expectation of life, major causes of death, deaths from
human immunodeficiency virus infection, and infant
mortality. Data by state of occurrence are shown for
birth, marriage, divorce, death, and infant death.
The report, "Annual Summary of Births, Marriages,
Divorces, and Deaths: United, States, 1991," is avail-
able, free of charge, from the Scientific and Technical
Information Branch, Division of Data Services, NCHS,
CDC, Room 1064, 6525 Belcrest Road, Hyattsville,
Maryland 20782; telephone (301) 436-8500.
Region VII
Region YE will offer the Workshop on Risk and Decision
Making from October 21 to 23 at the Regional Office. The
course will be co-facilitated by Mary Williams, from Re-
gion VII's Water Management Division, and Cherri
Baysinger-Daniel, from the Missouri Department of Health.
The course has been updated to include the revised case
study and has been extended to three days.
> Contact Mary Williams (913) 551-7415
Region X
Environmental Equity
Staff from Region X participated in the joint EPA/NIEHS/
ATSDR workshop in Durham, North Carolina on "Equity
in Environmental Health: Research Issues and Needs."
Approximately 75 attendees listened to presentations on
cross-cutting issues (Le., susceptibility, data collection/evalu-
ation, health status, and environmental justice), then split
into four workgroups, each devoted to a single environmen-
tal health problem: air pollution, hazardous waste, water
pollution, and pesticides.
In the water pollution workgroup, Region X staff brought
attention to Native Americans and new and recent immi-
grants, particularly Asian, whose populations and lifestyle
' characteristics challenge EPA's current default risk assess-
ment assumptions. For example, anecdotal information states
that some Asian immigrants collect and eat organisms that
tend to accumulate pollutants, such as invertebrates, marine
plants, and bottom fish. In addition, food preparation tech-
niques and the persons' lower body weights may lead to
higher exposures to such pollutants.
Based on discussions from the workshop, staff from the
Office of Health Research are preparing draft papers for
workgroup review. The final papers will be submitted to the
journal, Environmental Health Perspectives.
>• Contact Roseanne M. Lorenzana (206) 553-8002
Risk based Enforcement Targeting
Region X is leading an EPA-wide effort to improve and
automate risk-based targeting for inspections and enforce-
ment On September 22-24,1992, staff from the Office of
Research and Development and the Office of Enforcement
met in Seattle with the Region X team and the regional
directors of the Air, Water, and RCRA programs for a
review of the pilot approach. The discussions also covered
the toxicity and environmental vulnerability scoring meth-
ods and hardware/software issues.
In their pilot effort, Region X used the Toxic Release
Inventory (TRI) database, compliance monitoring informa-
tion available in the IDEA system, toxicity ranking, and air,
soil, water, and population characteristics in a Geographic
Information System (GIS) format Other ranking method-
ologies, including the TRI Indicator Methodology and the
Hazard Ranking System (HRS), were compared and dis-
cussed.
> For additional information, contact the Region X team
members:
Randy Bruins
Roseanne Lorenzana
Jim Hileman
Ray Peterson
Bill Schmidt
(206) 553-2146
(206) 553-8002
(206) 553-1640
(206) 553-1682
(206) 553-1586
Ecological Risk Analysis of the Mid-Snake River,
Idaho
Region X is working in cooperation with a group of scien-
tists from other federal and state agencies and academic
institutions to complete an ecological analysis of the Mid-
Snake River in Idaho. The analysis will be used to develop
a comprehensive policy (nonpoint source, endangered spe-
cies) and regulatory (water quality standards, total maxi-
mum daily loads) guidelines for this watershed. This type of
analysis would also provide a prototype for management of
other reaches of the Snake River and other river ecosys-
tems.
The upper Snake River Basin is a multipurpose resource
which is reaching its limits as demands for development
increase. Management issues are an overriding concern in
this basin because of long-term claims on the water and
nonpoint source effects. The dominant point sources are
hatcheries, feedlots, municipal sewage treatment plants,
and hydroelectric projects. The predominant nonpoint source
is agriculture. Irrigation diversions and return flows com-
prise the major impacts upon aquatic ecosystems at present
Future plans include the construction and modification of
hydroelectric projects. These issues must be resolved by a
thorough analysis of the problem, the sources, and possible
-------
options for corrective action which allow for future devel-
opment and alternative land uses.
An ecological risk analysis of the Snake River will be
completed using measurements and models to estimate the
likelihood of deleterious alterations in the riverine abiotic
and biotic systems for both the present and future river
conditions. A multicompartment water quality model is
used to characterize the ecological risks associated with
development options in the Snake River Basin between
American Falls Reservoir and King Hill, Idaho. Elements
of risk are derived from variability in flow, water quality
and quantity, outflow, meteorologic variability, and model
uncertainty compared to the variability in the environmen-
tal requirements for indicator organisms. Using the Geo-
graphic Information System, results from the ecological
analysis are tied to a planning model that provides a frame-
work for analysis of management options in the Snake
River Basin.
>• Contact Pat Cirone (206) 553-1597
IV. Meetings
Thirty-First Hartford Symposium on Health
and the Environment—October 20-23, 1992
The 31st Hanford Symposium, "Health and the Environ-
ment: The Development and Application of Biomarkers to
the Study of Human Health Effects," will be held October
20-23, 1992, in Richland, Washington. The symposium is
sponsored by the U.S. Department of Energy. Battelte, and
the University of Washington's School of Public Health
and Community Medicine.
>• For additional information, contact Dr. Ray Baalman,
Life Sciences Center, MSK1-50, Battelle, Pacific North-
west Laboratories, Richland, Washington 99352. The
phone number is (509) 375-3665.
Society of Environmental Toxicology and
Chemistry Meeting— November 8-12, 1992
The Society of Environmental Toxicology and Chemistry
will hold its 13th Annual Meeting November 8-12, 1992, at
the Cincinnati Convention Center in Cincinnati, Ohio.
The theme of the 1992 Annual Meeting is Environmental
Sciences and Resource Management in the 21st Century.
The meeting theme recognizes the necessity for environ-
mental scientists and resource mangers to become effective
teachers and communicators on the concepts of chemical
risk assessment, analytical chemistry, risk communication,
science education, economics, air toxics, land-use planning,
and life-cycle assessment The theme presents the challenge
for today's society to look at the earth as an integrated
system and develop the science and management practices
to ensure a healthy environment in the 21st Century.
The meeting will also include the following nine short
courses:
• Ecological risk assessment,
• Product life-cycle assessment: concept, methods and
applications,
• Sediment bioaccumulation tests: assessing sediment
bioavailability,
• How to conduct the frog embryo teratogenesis assay,
Xenopus (FETAX),
• A survey of regulatory quality assurance requirements,
• The fugacity concept in environmental modeling,
• Contaminant detection and effect technologies for trans-
fer to developing countries,
• Application of MINTEQA2 to ecological risk assess-
ment, and .
• Lake water quality modeling and trend analysis.
>• To attend the meeting, or for additional information,
contact the SETAC at 1010 North 12th Avenue,
Pensacola, Florida 32501.
HMCRI's 13th Annual National Conference
and Exhibition—December 3-6,1992
The 13th Annual HMCRI's National Conference and Exhi-
bition will be held December 1-3, 1992, at the Sheraton
Washington Hotel in Washington, D.C.
The conference will include
• 200 specialized technical papers,
• An exhibition hall with over 450 boqths featuring
companies displaying goods and services for hazard-
ous materials management,
• HMCRI Professional Certification Seminars, and
• OSHA Seminars.
Proceedings of every technical paper presented at the con-
ference will also be developed.
>• For additional information on the conference, contact
HMC/Superfund '92, 7237 Hanover Parkway,
Greenbelt, Maryland 20770-3602, or call (301) 982-
9500. The FAX number is (301) 220-3870.
National Childhood Lead Poisoning Prevention
Conference—December 7-9,1992
The Centers for Disease Control (CDC) will sponsor the
National Childhood Lead Poisoning Prevention Conference
December 7-9, 1992, in Atlanta, Georgia. Representatives
from state- and community-based childhood lead poisoning
prevention programs, state and local government agencies,
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private and public organizations and institutions, academia,
and child-health advocacy groups are expected to attend.
The goal of the conference is to strengthen childhood lead-
poisoning prevention programs and efforts nationwide
through information exchange and discussion about preven-
tion activities and scientific research. Conference topics
will include:
• Screening and follow-up,
• Managing the leaded environment,
• Community education and outreach,
• Epidemiology and Surveillance, and
• Directions for the future.
>• For additional information and registration materials,
contact Yvonne Chrimes, PACE Enterprises, Inc., 17
Executive Park Drive, Suite 200, Atlanta, Georgia
30329, or telephone (404) 633-8610. The FAX number
is (404) 633-8745.
HMCRI is accepting proposals for l-hour-and-15-minute
lectures, half-day programs, posters, 25-minute papers and
full-day seminars. Abstracts should range from 250 to 350
words, single spaced. Abstracts for meeting presentations in
the categories listed previously should be sent to HMCRI-
FER'93 at 7237 Hanover Parkway, Greenbelt, Maryland
20770-3602, by November 9. 1992. The FAX number is
(301) 220-3870.
Risk and Decision-Making Course Schedule
The following is the schedule for the Risk and Decision-
Making Courses through December.
October 21-23 Kansas City, Kansas
December 1-3 Sacramento, California
> Contacts: Jim Cole (202) 260-2747
Marian Olsen (212) 264-5682
Conference on Household Hazardous Wastes
Planned for December 8-12, 1992, in
Minneapolis, Minnesota
EPA will hold its Seventh Household Hazardous Waste
Conference December 8-12, 1992, in Minneapolis, Minne-
sota. The meeting will focus on reducing the amount and
toxicity of household wastes.
The conference is co-sponsored by the EPA and the state of
Minnesota. The registration fee is $135.00.
> For further information, call (301) 585-2898.
*****
2nd Annual Federal Environmental
Restoration Conference and Exhibition — May
25-27,1993
The Second Annual Federal Environmental Restoration
Conference and Exhibition will be held at the Sheraton
Washington Hotel on May 25-27. 1993. The conference is
being sponsored by the Hazardous Materials Control Re-
sources Institute from Greenbelt, Maryland. Participating
agencies include the U.S.:
Department of Energy,
Department of Defense,
Army Corps of Engineers,
Department of the Navy,
Environmental Protection Agency,
Bureau of Reclamation,
Air Force, Naval Facilities Engineering Command, and
Department of the Interior.
Contacts:
Jerome Puskin
Linda Tuxen
Dorothy Patton
Dick Hill
Don Barnes
Dean Hill
Maureen McClelland
Marian Olsen
Jeffrey Burke
Elmer Akin
Milt Clark
JonRauscher
Mary Williams
Suzanne Wuerthele
Arnold Den
DanaDavoli
OAR-RAD
ORD-OHEA
ORD-RAF
OPTS
SAB
NEIC
Region I
Region II
Region HI
Region IV
Region V
Region VI
Region VII
Region VIII
Region DC
Region X
(202) 260-9640
(202) 260-5949
(202) 260-6743
(202) 260-2897
(202) 260-4126
(202) 776-8138
(617) 565-4885
(212) 264-5682
(215) 597-1177
(404) 347-1586
(312) 886-3388
(214) 655-8513
(913) 551-7415
(303) 293-0961
(415) 744-1018
(206) 442-2135
If you would like to receive additional copies of this and
subsequent Reviews or to be added to the mailing list
contact
CERI Distribution
26 West Martin Luther King Drive
Cincinnati, Ohio 45268
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