Environmental Engineering Reference
In-Depth Information
8.4 RANKING COMMON PLASTICS
A reasonable approach to facilitating environmental sustainability is to
recognize particularly unsustainable plastic material in specific applications
and substitute these with more sustainable ones. Ranking the main classes
of plastics on the basis of their energy costs and fossil fuel use as well
as externalities generated during their manufacture (with special attention
paid to toxicity) is a useful starting point in assessing their environmental
sustainability. While the rankings are based on LCAs, their limited scope
and emphasis of selected environmental impacts such as recyclability or
impacts on human health must be appreciated. The available rankings are
material-specific and are not directly linked to specific application areas
and therefore cannot be easily used in making informed choices in material
selection. Attempts at ranking the common classes of thermoplastics
(Greenpeace, 1998; Institute for Agriculture and Trade Policy, 2008; Miller
et al., 2006; Van der Naald and Thorpe, 1998; Yarwood and Eagan, 1998)
including some by manufacturers of consumer goods (Henderson et al.,
2009; Opel Automaker, 2002) have been reported. Despite the differences
in the scope of LCAs these were based on and that they did not take specific
applications into account, the rankings obtained are very similar.
Early attempts yielded the highly publicized plastic pyramid (Greenpeace
International) shown in
Figure 8.4
. In 2005, a similar ranking was
developed and presented as a plastic spectrum (Rossi et al., 2005), where
the ranking based on environmental hazard was supplemented also by the
recyclability of the plastic. Along the same lines is the development of a
“plastic score card” where the resins are given a score ranging from A+
to F based on three core considerations of sustainable feedstocks, green
chemistry, and closed-loop system design. The general rankings of resins in
all studies were not that different from that in the original plastic pyramid
in
Figure 8.4
.
