Biomedical Engineering Reference
In-Depth Information
Environmental audits and environmental management systems provide and
structure information to guide industrial decision makers. Environmental
labeling (e.g., organic labels or carbon footprints) and environmental certi-
fication (an official statement of environmental performance, such as build-
ing certification by the Leadership in Energy and Environmental Design
Green Building Rating System) is used to communicate information to the
consumer.
These end-user tools rely on quantified analytical methods such as sub-
stance flow analysis, risk assessment, and LCA, which differ mainly in the
focus of the analysis. Substance flow analysis quantifies flows and reservoirs
of a given substance (e.g., lead) or of a group of substances (e.g., inorganic
nitrogen compounds) for a given region and time duration. Risk assess-
ment concentrates on the probabilistic risk for large production facilities
(e.g., nuclear power plants) or for the local impacts of toxic chemicals in a
region. The focus of LCA is to relate environmental impacts to the func-
tion of a product over its whole life cycle, from cradle to grave, considering
a wide range of pollutants and impacts. Because of this broad application,
the results are more comprehensive but with higher uncertainties. As these
analytical tools are all based on common elements, such as mass balance
and multimedia modeling, LCA developments are performed in collabora-
tion with specialists from the other domains described above. As discussed
by Jolliet and Small,
1
the human health component of Life Cycle Impact
Assessment (LCIA) aims to assess in a comparative way the multiple impacts
and large number of toxic substances that are involved in the life cycle of
products. This often differs from the scope of regulatory toxicological assess-
ments, which generally focus on ensuring that safe doses are not surpassed
by exposures at any location or point in time.
11.1.2 Different Steps of LCA
According to the definition provided in the ISO standards and SETAC, an
LCA consists of four steps.
Goal definition
defines the product or system func-
tion and the functional unit to which emissions will be related, as well as the
boundary of the system that meets this function. The next stage in LCA is
inventory
, which lists the resources extracted and pollutant emissions to air,
water, and soil for all the processes needed to achieve this functional unit. The
third stage,
impact assessment
, estimates the environmental impacts of these
emissions. Finally,
interpretation
identifies key processes and pollutants; per-
forms sensitivity, uncertainty, and cost-benefit analyses; and can assess the
improvement potential (Figure 11.1). LCA is meant to be an iterative procedure
(Figure 11.1), performed in at least two iterations. First, a screening should be
performed, covering all LCA phases, to assess the orders of magnitude of emis-
sions and related impacts. Then, focusing on the most damaging processes,
emissions, and life cycle phases, a more detailed analysis should be carried out
to improve the assessment quality. In the context of nano-based applications,
