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A current promotional program sponsored by the plastics industry emphasizes the positive contributions that plastics make. And claims listed in those advertisements are accurate.
But as shown in the article on the preceding page, the largest single use for plastics is packaging. Because packaging has a short lifespan, it makes up a large portion of the plastics waste stream. But where does that "waste stream" lead?
In general, the Environmental Protection Agency says that in the early 1990s about 80 percent of all municipal solid waste was sent to landfills, 10 percent was incinerated and 10 percent was recycled. While more and more plastic is being recycled, the EPA estimates that plastics make up about 20 percent of the solid waste that is landfilled.
Most consumers think that the slow degradation of plastics is the primary reason that plastics should be recycled. However, research has shown that other waste, such as paper, wood and food wastes, also degrade very slowly in landfills.
The more serious problem with plastic waste concerns the additives contained in plastics. These additives include colorants, stabilizers and plasticizers that may include toxic components such as lead and cadmium. Studies indicate that plastics contribute 28 percent of all cadmium in municipal solid waste and about 2 percent of all lead. Researchers don't know whether these and other plastic additives contribute significantly to products leached from municipal landfills.
How toxic are plastics that are burned? Researchers don't know that, either. Plastics that contain heavy-metal-based additives may also contribute to the metal content of incinerator ash. The EPA is looking for substitutes for lead- and cadmium-based additives.
One additional concern relates to use of petroleum products. All plastics began their lives as petroleum. By increasing plastics recycling, scientists and engineers are able to reduce dependence on petroleum.