Plastic bags don’t biodegrade

Re: “Paper or plastic,” July 10. To equate crude oil pumped from deep geologic formations miles beneath the surface with a petrochemical product buried in shallow subsurface soil is beyond preposterous.

Scientists estimate that supermarket-type plastic bags take 500-1,000 years to photodegrade (when exposed to ultraviolet radiation from sunlight). It hasn’t been studied long enough to say exactly how long. Supermarket plastic bags are made of polyethylene, a polymer that doesn’t biodegrade. Microorganisms don’t recognize it as food.

Plastic bags befoul our vegetation, sanitary sewer systems, and beaches. They accumulate in our oceans and threaten marine habitat. I suggest the letter writer bury some plastic bags in his backyard and dig them up 10 years later. He’ll find intact plastic bags.

George Johnson
La Crescenta

Editor’s Note: The writer is president of Athanor Environmental Services, Inc. in La Crescenta.