April 1, 2007
By a vote of 10-1, the San Francisco city leaders approved a partial ban on plastic bags, which requires large markets and drug stores to offer customers bags made of paper that can be recycled, plastic that degrades easily enough to be composted, or reusable cloth. San Francisco’s Mayor Gavin Newsom is expected to sign the ban into law.
The switch from plastic bags to alternative materials is scheduled to take effect in six months for grocery stores and in one year for pharmacies. A Newsday.com story reported that Craig Noble, a spokesman for the Natural Resources Defense Council, said it would be disappointing if grocers rejected the biodegradable plastic bag option, since more trees would have to be cut down if paper bag use increases, adding that the new compostable/biodegradable plastic bags “offer consumers a way out of a false choice, a way out of the paper or plastic dilemma.”
In related news, according to a March 27 report in Canadian Press, Leaf Rapids, in Manitoba, is considering creation of a plastic bag free zone, pending legal challenges to the municipal bylaw, resulting from debate whether such a ban would fall under the town’s “spheres of jurisdiction”. Rossland, British Columbia is also looking at a similar law.
A potential answer to such bans could come from ongoing developments in biodegradable plastics that would break down over time. At the American Chemical Society’s national meeting held recently at McCormick Place in Chicago, Robson Storey, a professor of polymer science and engineering at the University of Southern Mississippi (USM; Hattiesburg) presented a paper on a biodegradable resin intended for use on sea-faring vessels that would break down into natural byproducts in 20 days via hydrolysis. Cruise ships and the Navy have expressed interest, since considerable time, money, and space is used to store waste on the open seas until a port is reached. Based on a polyurethane modified with PLGA (poly D,L-lactide-co-glycolide), which is used in absorbable surgical sutures, the material can range from soft and rubber-like to hard and rigid. In the ocean, the plastics, which are actually denser than saltwater, would sink and break down into nontoxic components, including water, carbon dioxide, lactic acid, glycolic acid, succinic acid, caproic acid, and L-lysine. The material has garnered interest from the U.S. Army Natick Solider Research, Development and Engineering Center (Natick, MA), which is conducting tests in the Gulf of Mexico at the USM Gulf Coast Research lab in Ocean Springs, MI.
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