A SUSTAINABILITY PRIMER - Plastics and Environmental Sustainability - page 69

1. The epoxy liners in tin cans leach bisphenol A (BPA), an endocrine
disruptor, into the food contents. Ingesting even low levels of BPA is a
health concern. While BPA-free cans with no epoxy liners are
available, they are about 15% more expensive compared to
conventional cans. Despite this disadvantage, some canned-food
manufacturers 20 have switched to the BPA-free cans.
2. Some skin care preparations use polyethylene microbeads that serve
as exfoliants. The particles in municipal waste reach the oceans via
wastewater and are potent marine pollutants as well as a pathway
that introduce concentrated persistent chemicals (POPs) in seawater to
the marine food web (microparticles; see Chapter 9 ). On recognizing
the environmental damage posed by these, several leading
manufacturers 21 have pledged to phase out their use of these and to
undertake research to identify nonpolluting replacement.
2.5.1.9 Converting the Pollutants into Resources
Carbon dioxide is a pollutant of immediate interest, and most operations in
the plastics supply chain emit CO 2 into the atmosphere. Emerging research
suggests that emissions from industry might be used to produce polymer
raw materials:
1. Waste CO 2 can be captured and converted into poly(propylene
carbonate) [PPC] plastic. Large-scale conversion of the waste gas into
PPC has been demonstrated . 22
The critical component is a proprietary catalyst developed by the
innovators. As more uses for this plastic and its copolymers and blends
are found, this can be a valuable means of converting waste CO 2 into a
resource.
2. Using a different technology (Joule Unlimited, MA), waste CO 2 is
mixed with algae or cultures of microorganism exposed to sunlight to