Greenware—Is It Green?

During the recent heat wave here in Ithaca, NY, I drank a lot of takeout iced coffee from my local café, Gimme! Coffee. I noticed something weird happening to the empty plastic cups left behind in the sweltering car: They were shrinking, sort of melting in onto themselves. The lids read "Greenware." I began to notice these cups all over town, even at our local Wegmans. What was going on?

Research soon yielded the happy revelation that the Food and Drug Administration (FDA) has approved drink receptacles made of PLA (polylactides), a polymer derived from corn. Smooth, clear and visually indistinguishable from petroleum-based plastics, the material for these cups is produced by NatureWorks LLC, a branch of Cargill Dow. PLA plastics biodegrade completely in 90 days in commercial or institutional composters, require 50 percent less fossil fuel than regular plastics to produce, and are not toxic to burn.

Polylactides are derived from starch, in this case corn dextrose. According to NatureWorks, lactic acid, a substance naturally occurring in the human body, is itself already used as a food additive. Polylactides have also been used for many years by the medical industry because it is bioresorbable, meaning it is absorbed by the body, thus making it an ideal material for implants and internal sutures. The FDA hasn't found that PLA leaches any toxic chemicals, which gives it an advantage over some plastics commonly used for holding liquids, such as polycarbonate, which can leach hormone disupting bisphenol-A, and polystyrene, which can leach styrene, a possible human carcinogen.

This year NatureWorks will use the dextrose from 13 million bushels of field corn, a variety grown for animal feed, to produce this new plastic resin. Unfortunately, they use genetically-engineered (GE) corn as well as non-GE corn. Genes from GE crops have already spread to certain populations of US and Mexican non-GE corn. Serious risks to human health could result, according to the Union of Concerned Scientists, if genes from pharmaceutical and industrial crops contaminate the seeds for food crops at a significant level. And though not oil-based, the synthetic fertilizers used on them can be.

So far just cold disposable cups, available from many distributors, such as Green Earth Office Supply (greenearthofficesupply.com), are in circulation since this type of PLA can withstand liquid temperatures only up to 110 degrees F. But NatureWorks and others hint at a disposable PLA hot cup in the imminent future. Several companies, including Quickpoint and Jamplast, already manufacture and distribute nondisposable hot cups made entirely from corn.

When composted in commercial or institutional composters the cups will disappear completely in 47 days, according to NatureWorks, but only if the composter is run at a temperature above 140 degrees F, slightly higher than most commercial composters consider optimal. Fabri-Kal, the Michigan company that manufactures the cups, says the cups go away in closer to 90 days in standard commercial composters. NatureWorks is currently compiling a nationwide list of institutional composters (check their web site below). People who have mixed the cups into their home composts, cooler and drier than commercial setups, generally agree the cups disappear in around a year, although it helps to cut them.

My cold drinks taste just fine in Greenware. PLA plastic cups aren't perfect, but they aren't a petroleum product and appear to be completely safe for the consumer. Another iced latte, please!

Resources

Good Earth Office Supply: www.greenearthofficesupply.com, 800 327-8449

Natureworks: www.natureworksllc.com