Page 208 - Design for Environment A Guide to Sustainable Product Development

186 Cha pte r Ni ne

Risk analysis is a complex subject, spanning a broad variety of
risk sources, mechanisms, endpoints, and mathematical techniques.
Despite the large amount of literature that has accumulated regard-
ing environmental risk analysis, the methods are still evolving due
both to theoretical advances and new empirical findings. Funda-
mental limitations on what is knowable (e.g., the “true” impacts on
human populations of chronic low-level exposures) will continue to
force reliance on predictive models, so that scientific debate over risk
assessment methods may never be fully resolved. As a consequence,
decision making regarding the mitigation of risks will continue to be
challenged by the presence of significant assumptions and uncer-
tainties in the available information, including the following:

• Types and magnitudes of risk agents, such as hazardous mate-
rials, waste and emissions, and ionizing radiation.
• Possible initiating events leading to unplanned releases, such
as leaks, spills, fires, explosions, or deliberate human intrusion.
• Fate and transport mechanisms that describe how released
agents are dispersed in the environment and partitioned
among air, water, soil and other elements, as well as how they
are chemically and physically transformed.
• Categories of receptors that may be exposed to released agents,
including workers, community residents, sensitive popula-
tions (children, pregnant women, etc.), natural vegetation and
wildlife, aquatic organisms, and domestic animals and crops.
• Exposure pathways, or routes, whereby humans and other
biota may be exposed to released agents or their by-products,
including inhalation, uptake through direct contact, inges-
tion in water, and bioaccumulation in the food chain.

Despite data limitations, it is still possible to develop and apply
an objective decision-making process that takes into account the
degree of uncertainty in risk estimates, as well as the relative impor-
tance of the corresponding endpoints from the perspective of dif-
ferent stakeholders. Moreover, it is possible to factor this type of

in formation into a risk/cost/benefit analysis such that the associ-
ated trade-offs can be explicitly communicated to a variety of inter-
ested parties. To pursue such an approach requires great attention to
the quality, adequacy, and credibility of the information upon which
the analyses are based.
There are certain situations in which the traditional approach to
risk analysis and management is not adequate. As the boundaries of
the system become broader, several limitations emerge: increasing
complexity, uncertainty, and interdependence with other systems