Page 243 - Materials Chemistry, Second Edition

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TABLE 6.1
Comparison of Environmental Risk Assessment and Life-Cycle Assessment

Criteria Environmental risk assessment Life-cycle assessment
Object Industrial process or activity Functional unit, i.e., product or service,
with its life-cycle
Spatial scale Site specific Global/site generic
Temporal scale Dependent on activity Product life
Objective Environmental optimization by Environmental optimization by
risk minimization reduction of potential emissions and
resource use
Principle Comparison of intensity of Environmental impact potential of
disturbance with sensitivity of substances
environment
Input data Specific emission data and General input and output of industrial
environmental properties processes
Dimension Concentration and dose Quantity of emissions
Reference Exposure potential to threshold Characterization factor
Result Probability of hazard Environmental effect score

integrated, is outlined in Table 6.1. The comparison is illustrated by the example of
electricity generated from coal and produced in the same way but in two different
regions, in which the combustion of coal is obviously an important part of the life-
cycle:

• Case 1: in a very populated and acidification-sensitive area next to the
mining site
• Case 2: in a purely populated and no acidification-sensitive area far from
the mining site

According to Sonnemann et al. (1999), the LCA will probably state the minimal
total emissions and energy demand for Case 1 due to the importance of the additional
transport and the negligence of the specific region. By contrast, the ERA will state
the minimal risk to the environment for Case 2 because the focus is put only on the
main process within the life-cycle, but the extra transport is not considered. This
example shows in a simple way the significance of the difference highlighted in
Table 6.1. It also clearly demonstrates the need for a more integrated approach that
does not so easily allow two environmental impact analysis tools to provide such
contradictory and inconsistent results.
Olsen et al. (2001) emphasize the feature of LCA as a relative assessment due
to the use of a functional unit, while ERA is an absolute assessment that requires
very detailed information, e.g., on exposure conditions. It is concluded that the
conceptual background and the purpose of the tools are different, but that overlaps
in which they may benefit from each other occur.

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