PRINCIPLES OF TOXICOLOGY

TABLE 18.8 Examples of Risk Communication Problems
Source of Problem Examples
Source of the message The source of the risk information, usually a governmental or industrial entity or
representative, is not trusted
Any disagreements among scientific experts make the information appear to be
guesswork
There is often a reluctance to disclose limitations and uncertainties in the risk
estimates
The risk assessment may not address issues of greatest concern to individuals
and communities
The message Risk estimates may have large uncertainties due to limitations in models,
methods, and data used in the risk assessment
The inherent technical nature of risk assessments makes them difficult for
laypersons to understand
Use of jargon and bureaucratic and legal language make risk assessments even
more incomprehensible
Channel for conveying the Media interpretation may result in presentation of oversimplified, distorted, or
message
erroneous information
Media emphasis on drama, wrongdoing, or conflicts clouds presentation of risk
information
Eagerness by media to report may result in premature disclosures of scientific
information
Receiver of the message Public perceptions of risk are often inaccurate
There may be unrealistic demands for scientific certainty in risk estimates
There is usually a lack of interest in the technical complexities of the risk
assessment, and therefore a poor understanding of what risk estimates
represent
Not everyone will be open-minded; some individuals with strong opinions and
beliefs will not be receptive to new information
There is often an unwillingness or inability to view risks in context, understand
risk tradeoffs, or view risk problems from a perspective other than that of their
own perceived immediate interests
Source: Adapted from Cohrssen and Covello (1989).
18.9 RISK COMMUNICATION 473
communication. Unfortunately, all too often, the answers conveyed by the risk assessment can seem
ambiguous. Scientists are trained to be circumspect in their conclusions and carefully point out any
caveats in their analysis. This certainly applies to risk assessments, where responsible presentation of
risk estimates is always accompanied by a discussion of the many areas of uncertainty and limitations
in the analysis. When all of the caveats and uncertainties are presented along with the risk estimate,
the uncertainty looms large and it is easy for the public to conclude that “They don’t really know what
the risk is.” When this happens, regardless of whether the risk estimates themselves are large or small,
they have little credibility. Thus, the dilemma for the risk communicator is how to adequately convey
the underlying uncertainties in the risk estimates without losing the essential message that the risks
are large or small, as the case may be.
Deciding whether a risk is acceptable requires, in part, placing that risk in context. Thus, the risk
from a particular chemical or set of exposure circumstances must be compared with other risks to the
individual or population in order to place that risk in perspective. While this is straightforward in
concept, it is difficult in practice, particularly when communicating risk to the general public. One
reason is that the public, unaccustomed to seeing typical risk assessment outputs, may have little basis
for comparison. Unless someone has experience with, or is shown, comparative risk data for a variety
of hazards, it is difficult for them to know whether a 1 × 10 –5 risk is significant. For noncancer health
effects, the meaning of outputs in terms of hazard index or margin of exposure is even more obscure.
How, for example, would you help citizens place a hazard index of 3 for a chemical exposure in the
context of risk from events in their everyday lives?