Environmental Engineering Reference
In-Depth Information
of different plastics or materials of construction for a specific application
area such as potable water pipes, greenhouse glazing, insulation of homes,
orpackagingofclassesoffood.Ultimately,thesustainablechoiceofaplastic
for a given application is one that delivers the required functional attributes
at the minimum ecological footprint. At times, this may unavoidably
indicate a generic plastic with a poor environmental rating. High
environmental costs are often accommodated for indispensable societal
services. If the societal benefit of the product is high enough, it will still be
manufacturedandused.Sustainablegrowthintheseinstancesstilldemands
research to find an adequate replacement and strategies to mitigate the
hazard associated with the product, not its substitution with a product of
reduced functionality.
8.4.1 PVC
Most comparative assessments of plastics find PVC to be a particularly
low-ranking, thereforeanundesirable, plasticmaterial (Lindahl etal.,2014)
that needs to be phased out, especially in packaging and building uses.
Its production, use, and disposal are in fact beset with a range of adverse
environmental impacts (Thornton, 2002). There is a large enough body
of literature that suggests the use of PVC is associated with a particularly
high environmental cost. In some applications, PVC does not offer unique
functionality that would justify that high an environmental cost.
The major uses of PVC in buildings include pipes, window frames, siding (in
the United States), roofing, and flooring. The US Green Building Council,
however,recommendsagainsttheuseofPVCinsustainablebuildingdesign.
The key environmental issues associated with PVC use are as follows.
a. Over half the weight of PVC is made up of chlorine! Chlorine production
is energy intensive and consumes approximately 1% of the world's
electrical energy. Large-scale synthesis of the vinyl chloride monomer
(VCM) results in inevitable emission of traces of chlorine, the
carcinogenic monomer, and possibly dioxins, into air. The chlorine-rich
waste (~1 million tons annually) from the process is incinerated,
highly toxic chemicals and the acceptable daily exposure set by EPA is
concern, potential for accidental spills where transport of VCM and Cl
2
is involved, as well as an air pollution issue. Mercury chloride was used
