I must admit that I've fantasized about appearing on Oprah. What an opportunity to demystify chemistry that would be! But I think the closest I'll ever come will be answering a question from one of her researchers.
It seems Oprah has an interest in polystyrene, because the researcher wanted to know whether it was true that this plastic will take hundreds of years to break down in the environment. Undoubtedly the question was motivated by environmental issues, with some towns now considering banning one of polystyrenes major incarnations, those ubiquitous foamed food and beverage containers.
This is not the first time that foamed polystyrene has plucked at environmental heartstrings. Back in the late 1980s a grassroots movement caused McDonald's and other fast food restaurants to eliminate foamed packaging. At that time the major concern was over chlorofluorocarbons (CFCs), chemicals used in the production of polystyrene foam, which were being implicated in the destruction of the ozone layer. This is no longer an issue, as CFCs have been replaced by pentane or carbon dioxide that is more environmentally friendly.
Today, worries about polystyrene focus on the toxicity of chemicals used to make the material, on the possibility of residual styrene leaching into food from containers, and on the non-biodegradability of the substance. Certainly, polystyrene is not readily biodegradable. But neither I, nor anyone else, can confirm that it will take hundreds of years for polystyrene to "break down" in the environment. It has not been around for hundreds of years, so we don't know exactly how long it takes to break down. Based on the evidence we have, however, we can assume that it will in-deed take a very long time to biodegrade, especially if the polystyrene ends up in a landfill. But is this an environmental horror? Not at all! First, a little background information is in order.
Polystyrene is one of our most useful plastics and has been manufactured for commercial use since the 1940s. It is made from styrene, an oily liquid derived from petroleum. This brings up yet another is-sue about the material. Are we squandering some of our non-renewable resources on the making of this plastic?
Hardly. Less than a fraction of one per cent of our petroleum reserves is needed to produce all polystyrene products. And there are loads of these. Although when polystyrene is mentioned, most people conjure up images of foamed clamshells and coffee cups, the substance is widely used to make articles ranging from computer cabinets and toys to insulating panels. Traces of styrene, the raw material used to make polystyrene, are always present in the finished product, and in the case of food and beverage containers, can leach out into the contents, particularly if these are hot. This is of some concern since styrene, based on laboratory evidence, is a potential carcinogen. But studies of workers exposed to the chemical have not revealed any increase in cancer rates, so it is most unlikely that drinking that occasional cup of coffee from a polystyrene cup is a problem.
In an ideal world, all our garbage would be chewed up by microbes and converted into harmless substances such as carbon dioxide, simple nitrogen compounds and water. Pile up some leaves, paper and food scraps in the back yard, and you can watch this happen. That's what composting is all about. But throw a foamed polystyrene coffee cup on the compost pile, and it will remain untouched. Bacteria do not look on it as a tasty morsel, meaning that it is non-biodegradable.
Consider, though, that if you dispose of all this garbage in an airless landfill instead of a corner in your back yard, biodegradation is severely impaired. Even "biodegradable" food packaging made of polylactic acid (PLA); a darling of environmentalists because it is derived from corn, will not degrade.
Of course, the situation is different if the garbage ends up in an industrial composting facility, but not much of our waste does. How big an issue is non-biodegradability in a landfill?
Not very really! In fact, it is biodegradation that can lead to sub-stances that leach out of landfills, although modern landfills are constructed to prevent any environmental contamination. Polystyrene products may indeed sit in that landfill for hundreds of years, but they do so harmlessly. And they don't take up much space. Easily compressible polystyrene products occupy less than one per cent of the volume in landfills. Maybe they deserve the rest after they have helped protect our fragile articles during shipping and provided us with food containers that are hygienic, do not leak, and keep hot foods hot and cold ones cold. True, after use, food containers often end up as litter on streets. But that is not the plastic's fault; it is people's fault. Appropriate use and proper disposal is the key.
Polystyrene can be readily recycled where facilities exist, and today's food containers can end up as tomorrow's insulating panels that reduce your heating and cooling costs. While polystyrene does bring up some environmental issues, let's not lose sight of its valuable contributions. Automobile parts, life-saving flotation devices, laboratory equipment, television sets and, of course, all sorts of food containers are made of polystyrene.
And what would the people clamouring to rid our world of polystyrene food containers suggest we replace them with? Paper? Bringing home a fruit salad from the deli in a paper container is hardly the solution. Furthermore, paper is no better at degrading in a landfill than polystyrene, and occupies more space than the plastic. As far as energy investment goes, it takes more to produce paper than polystyrene.
So, now I think I'll go and enjoy a yogurt from a polystyrene container. And I'll hang on to that container in case Oprah calls. It can make for a real neat demo. I'll give you a hint. Shrinky Dinks, a children's arts and crafts product, are made of polystyrene.
Prof. Joe Schwarcz is Director of McGill University’s Office for Science and Society (OSS). It is dedicated to disseminating up-to-date information in the areas of food, food issues, medications, cosmetics and health topics in general. Dr Schwarcz teaches a variety of courses with emphasis on health issues and on the application of chemistry to everyday life. Professor Schwarcz has received numerous awards for teaching chemistry and for interpreting science for the public. Among these are the Royal Society of Canada’s McNeil Award and the American Chemical Society’s prestigious Grady-Stack Award. Dr. Schwarcz is the only non-American ever to be honored with this prize. His latest award is the Royal Canadian Institute’s Sandford Fleming Medal.
He was the chief consultant on the Reader’s Digest best sellers “Foods That Harm, Foods That Heal” and “The Healing Power of Vitamins, Minerals and Herbs” and contributed the chemistry chapter to the best-selling “Mental Floss.” His books “Radar, Hula Hoops and Playful Pigs,” “The Genie in the Bottle,” “That’s The Way The Cookie Crumbles,” “Dr. Joe and What You Didn’t Know,” “The Fly in the Ointment” and “Let Them Eat Flax” have been best sellers. The books have been translated into five languages and are sold around the world. His next work, “An Apple A Day,” is set to appear in December.