Health Risk Science - U.S. National
Research Council Risk Assessment Framework
The
National Research Council was established by the United States National
Academy of Sciences in 1916 to advise the federal government within
the broad community of science and technology. Upon the
initiative of the United States Congress, the National Research Council
conducted a study to strengthen the reliability and objectivity of
the scientific assessment that forms the basis for federal regulatory
policies pertaining to carcinogens and other public health hazards. This
study was conducted under contract with the U.S. Food and Drug Administration
within the Department of Health and Human Services.
The
NRC (1983a) model consists of two stages: risk assessment and risk
management (see figure) {National Research Council 1983 234 /id}. Risk
assessment refers to the use of a factual base to define the health
effects of the exposure of individuals or populations to hazardous
materials or situations. Elements of risk assessment are numerous
and include a description of the potential adverse health effects
determined in epidemiological, clinical, toxicological, and environmental
studies. Results obtained from research need to be extrapolated before
the type and extent of health effects in exposed humans to a specific
substance can be predicted. Risk assessment also includes judgments
on exposed individuals to determine the number and characteristics
and those exposed at a range of intensities and durations. Finally,
risk assessment can facilitate summary judgments on whether any public-health
problems are factual and important while taking into account uncertainties. Risk
management is the process of evaluating regulatory options and selecting
from among them.
Risk
assessment is subdivided into four components: hazard identification,
dose response assessment, exposure assessment, and risk characterization.
The process of risk assessment doesn’t always contain all four
components because it is possible that no adverse health effect is
found, and no further analyses are required. At the risk management
stage, alternative regulatory options are developed and evaluated.
Selection of a particular regulatory option involves consideration
of the public health, economic, social, and political consequences
of implementation.
The
NRC model was subsequently adopted by the United States Environmental
Protection Agency (1984) {United States Environmental Protection
Agency 1984 245 /id} with no significant structural or definitional
changes. The United States Department of Health and Human
Services (DHHS) {United States Department of Health and Human Services
1985 244 /id} has expanded the NRC model to include consideration
of nonregulatory options for risk management. These include
advisory options as well as risk reduction through technological
means. The DHHS also recommends expansion of research
so as to reduce the uncertainties associated with scientific knowledge.
U.S. National Research Council Framework
for Risk Assessment (1983)
National Research Council. 1983. Risk Assessment in the Federal
Government: Managing the Process. National Academy Press, Washington,
D.C. |
