A environmentally conscious we are increasingly concerned
about the enlironmental component of product and service
options available in our duent society. Our choices are often made
instinctively, from necessity, since a detailed analysis of the relative
envkonmental merits of using canned versus fresh versus frozen
foods, or glass versus paper versus steel versus aluminum packaging
would simply be too time consuming for each purchase. If, however,
the environmental merit question is resmcted to a small enough
purchase sector it is possible to conduct a complete analysis of
relative merit from the initial resource throwh tl~g~~mww
use attributes. and re~&o-gtJ-rou&mj&d~~~~r G sal of the item. Many environmentally appropriate choices of
products can o y made after such an analysis. An outline of one
such analysis, that of paper versus polystyrene foam as the material
of construction for hot drink containers in fast food or other single
use applications, is given here.
The major raw material for a paper cup is wood, a renewable
resource. However, acquisition of wood for pulp-making has visible
negative impacts on the landscape from the construction of road
access and typical clear-cutting practices. When the clear-cut area
occupies an extensive proportion of a watershed it increases maximum
flows and decreases minimum flows of streams draining the
watershed, increashig the likelihood of flood and drought in the area
served by these streams (1).
A polyfoam cup is made entirely from hydrocarbons (oil and gas).
Impacts from petroleum exploration and recovery are significant,
fiom the former particularly in sensitive northern ecosystems and
from the latter predominantly from accidental spills during drilling,
production, or delivery, which can cause widespread direct and
indirect harm to dected areas as well as resident plants and animals.
But since production of a paper cup consumes as much hydrocarbon
as a polyfoam cup (Table l), acquisition of the raw materials for its
production includes both the wood acquisition and the hydrocarbon
acquisition requirements necessarily causing the greater environmental
impact.
Paper cups are made from bleached pulp, which in turn is
obtained in yields of about 50% by weight from wood chips (2).
Bark and some wood waste are also burned to supply a part of the
energy requirements of the papermaking process. Thus an average of
some 33 g of wood plus, for additional energy requirements, an
average of about 4 g of residual fuel oil or natural gas, is consumed
per paper cup with a finished weight of 10.1 g. More petroleum
than this would be needed if the paper cup had a plastic or wax
coating, but this option is excluded in the estimate given here.
Inorganic chemicals are also required for the papermaking process.
Relatively small amounts of sodium hydroxide or sodium
sulfate are needed for chemical pulping makeup requirements, since
the recycle of these in the kraft pulping process is quite efficient. But
larger amounts of chlorine, sodium hydroxide, sodium chlorate