United States
Environmental Protection
Agency
Office of Health and
Environmental Assessment
Washington DC 20460
Research and Development
EPAV600/S6-87/008 July 1988
&EPA Project Summary
Recommendations for and
Documentation of Biological
Values for Use in Risk
Assessment
This document was prepared by
the Office of Health and Envi-
ronmental Assessment, Environ-
mental Criteria and Assessment
Office, Cincinnati, OH, for the Office
of Solid Waste and Emergency
Response. This document consists
of an extensive compilation of values
gleaned from published literature
sources for lifespan, body weight,
food consumption, water con-
sumption and inhalation volumes for
a wide range of predominately
mammalian species. Synthesis of
this information to provide recom-
mendations concerning parameters
for conversion of exposure data
(drinking water, food and air
concentration) from mammalian
toxicological studies to dose esti-
mates in units of milligrams/kilogram
body weight/day is provided.
This Project Summary was
developed by EPA's Environmental
Criteria and Assessment Office,
Cincinnati, OH, to announce key
findings of a research project which
is fully documented in a separate
report (see Project Report ordering
information at back).
Introduction
Reference values for parameters such
as food consumption, fluid consumption
and ventilatory volume have been widely
utilized across the Agency to estimate
mg'kg/day doses from experimental
exposure concentrations expressed as
ppm in air, water or food. While it is
preferable to utilize measured param-
eters specific to the particular study,
frequently these data are not reported.
Estimation of a mg/kg/day dose was
historically an integral component of
Acceptable Daily Intake (ADI) devel-
opment and currently is required for
Reference Dose (RfD) and Reportable
Quantity (RQ) calculations. Reference
values for body weights, while important
for the above uses, are also required (in
the absence of experimental values) for
surface area estimates, which are utilized
in both the RQ and cancer meth-
odologies. The only Published Agency
guidance concerning which values to
utilize in risk assessment are allometnc
equations for food con-sumption and
ventilatory volume for rats and mice.
These equations were given in the
Methodology for the Ambient Water
Quality Criteria Documents and were
based upon an extremely limited data
set.
In the absence of formal guidance, ad
hoc positions have been developed,
which differ across the different Agency
offices. These differences frequently re-
sult because each office has utilized a
different, small subset of the available
data as a basis for their reference values
While the variability introduced by
these differing values is generally quite
small in a quantitative sense, qualitatively
this variability has profound effects in
terms of apparent consistency of risk
assessment numbers across offices. In
addition, achieving agreement concerning
these numbers within the framework of a
particular risk assessment where several
offices are involved frequently requires
utilization of time and resources, which
could be better applied to the resolution
of other issues.
This document provides the first
extensive compilation of experimental
data for these parameters for all of the
commonly used laboratory species
including values for food and water
consumption, inhalation volume, body
weight and lifespan. This database is
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synthesized to provide recommendations
concerning parameters for conversion of
exposure data (food, water or air
concentration) into dose estimates in
units of mg/kg body weight/day. It is
anticipated that these recommendations
will be of utility for risk assessment in
terms of estimating doses from
mammalian toxicology studies when the
studies fail to report intake values for the
experimental animal relevant to the
medium in which the toxicant is
administered.
Results and Conclusions
Data are presented in two forms,
estimates of each parameter for animal
of unknown body weight, as well as
allometric equations for parameter
estimation for animals of known body
weight. Data were adequate to provid
estimates of inhalation volume, bod
weight, food and water consumption fc
twelve mammalian species Parameter
were estimated separately for mdividuc
sexes and strains wherever data allowec
This document is currently undergoim
evaluation as a potential framework ti
achieve a consensus agreement con
cernmg default physiological parameters
Karen Blackburn is the EPA Project Officer (see below).
The complete report, entitled Recommendations for and Documentation of
Biological Values for Use in Risk Assessment," (Order No. PB 88-179
874/AS; Cost: $32.95, subject to change) will be available only from:
National Technical Information Service
5285 Port Royal Road
Springfield, V'A 22161
Telephone: 703-487-4650
The EPA Protect 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
Official Business
Penalty for Private Use $300
EPA/600 S6-87/008
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