166 Introduction to Renewable Biomaterials
Outputs Category Unit Amount Comments
S,S,S-tributyl
phospho-
rotrithioate
Water/unspecified kg 8.74E−06 Pesticides – consumption,
Pesticides – application
method, Ru
Sodium chlorate Water/unspecified kg 1.16E−05 Pesticides – consumption,
Pesticides – application
method, Ru
Suspended solids,
unspecified
Water/unspecified kg 1.02E+01 Erosion
Trifluralin Water/unspecified kg 1.02E−05 Pesticides – consumption,
Pesticides – application
method, Ru
“*” denotes the meaning ‘per’.
“a” denotes the meaning ‘year’.
Life-Cycle Impact Assessment
LCIA is the third sequential step of an LCA. The purpose of an LCIA “is to provide
additional information to assess LCI result and help users better understand the
environmental significance of natural resource use and environmental releases”. The
LCIA helps provide significance and simplify results for easier decision making;
however, it is important to understand that it does not directly measure the impacts of
chemical releases to the environment as an environmental risk assessment does. The
third step of LCIA follows sequentially after the LCI using the many flows to and from
the environment developed in the LCI. These LCI flows without an impact assessment
step are not easily interpreted, and understanding the significance of emissions can be
impossible (Figure 5.6).
The LCIA as previously mentioned is different from a risk assessment measuring
absolute values of environmental impacts; rather, the LCIA helps determine the
significance of emissions and impacts in relation to the study scope. The absolute
value of the impacts cannot be determined by the LCIA due to (Margni and Curran,
2012)
- the relative expression of potential environmental impacts to a reference unit;
- the integration of environmental data over space and time;
- the inherent uncertainty in modeling environmental impact;
- the fact that some possible environmental impact occur in the future.
Even though the LCIA has limitations, it is useful in determining what impacts matter
the most, what unit processes are contributing most through hot spot analysis, and help
identify best-scenario options when environmental trade-offs occur.
According to ISO, there are three mandatory processes of an LCIA including selection
of impact categories, classification, and characterization (Figure 5.7).
5.3.2.10 Mandatory Elements
Selection of Impact Methods The selection of impact methods should reflect the intent
and methods outlined in the goal and scope of the study. The impact indicators of the
LCIA method must reflect the purpose of the study and examine the resources or
