Polystyrene: The Beady-Eyed Monster
How is it made?
Polystyrene is formed from hydrocarbon styrene (C8H8 ) through suspension polymerization, a process by which tiny drops of styrene are completely surrounded by a water-based solution. These droplets are then heated by radiation at about 212 degrees Fahrenheit, forming polystyrene beads. After the beads are cooled, washed, and dried, the beads are blown with steam. This steam expands the beads and decreases its density to about 3 percent of its original value, which accounts for the lightweight nature of polystyrene foam. Once the beads have been steamed, they are aged for a period of 24 hours, and then fed into a mold of the desired shape. The molded beads are steamed once again for fusion, and then they go through their final stage of cooling and rinsing. After that, the foam is cut, packaged, and shipped to vendors, and often ends up in the hands of consumers as a coffee cup or a to-go plate.
The Environmental IMPACT: According to the EPA's Toxic Release Inventory, more than 32.5 million pounds of styrene were released into the atmosphere in year 2008 alone. What does that mean for the environment? The presidents of leading polystyrene manufacturing companies would have you believe that this has no effect on the environment, since CFC use in polystyrene production was banned in the late 1980s. However, although polystyrene production no longer depletes the vital ozone layer (stratospheric level), it's actually contributing to ground level ozone (tropospheric level), which is just as detrimental, as it causes smog and heavily depleted air quality. This smog results when naturally prevalent nitrogen oxides in the air react with man-made hydrocarbons like polystyrene. So abounding quantities (like 32.5 million pounds) of styrene in the atmosphere does, in fact, affect the environment. See illustration below.
In addition to its problematic production, polystyrene poses another issue on its back end. It is classified under resin code 6, which means it's extremely difficult to recycle. The Foundation for Advancements in Science and Education reported that polystyrene accounted for up to 30% of all plastic found in land-fills. This is primarily because of the costly recycling process. Polystyrene foam has a much lower resell value than other plastics, and can only be resold if collected and baled into pallets of at least half a ton. Because of its very light weight, it takes very large quantities of uncontaminated recycled polystyrene to produce one viable pallet. For this reason, most curbside recycle companies have opted against accepting polystyrene foam altogether.
On the bright side, there are some other options for recycling expanded polystyrene. Locally, Publix grocery stores provide bins for collection, and Polymer Sciences Inc. off of Fulton Industrial Blvd. has a drop off for recycling expanded polystyrene. Although collected cups and containers are recycled into other products like CD cases and plastic ware, it requires an addition of virgin product resulting in the use of more energy and raw resources. This makes recycling for the sake of saving energy and materials virtually impossible.
The Health IMPACT: Although there is currently no emissions regulation on polystyrene, the EPA has established a ground water regulation. The maximum contaminant level (MCL) set for styrene is 0.1 parts per million (ppm). The EPA has found that health effects caused by short-term exposure to styrene at levels higher than the MCL include damages to the nervous system such as depression, loss of concentration, weakness, fatigue, and nausea. Long-term exposure to styrene levels at levels higher than the MCL include liver and nerve tissue damage, and even cancer. These findings are consistent with the reports of the International Agency for Research of Cancer, as they have categorized styrene under section 2B, “possibly carcinogenic to humans”.
How are we directly exposed to styrene, anyway? Well, we eat it. Every time we drink from a polystyrene cup, or heat up left-over food in its to-go plate, those containers lose weight. This means that the styrene chemical breaks down and leaches into the very things that we consume, making us directly susceptible to the health effects listed above.