Dissecting sides on the PVC issue

Welcome to the great vinyl debate - not unlike a recent heavyweight title bout, minus the biting. In this corner, wearing green and weighing in with a genuine concern for Mother Earth, we have environmental watchdog groups such as Greenpeace who contend that polyvinyl chloride is a big contributor to dioxin production. In the opposite corner, wearing a different shade of green, are manufacturers and industry groups such as the Vinyl Institue, presenting evidence of PVC's recyclability and environmental friendliness. Ready to rumble?

Marketing campaigns don't always attempt to sell products. Sometimes, the target is perception. Following in the advertising industry's "perception-is-reality" footsteps, environmental groups such as Greenpeace use the familiar symbol for poison as a logo for PVC. And to the general public, skull-and-crossbones images married to vinyl might actually wash. Tactics such as these play on awareness of and concern for the environment. But selling this image to an audience of plastics industry insiders is a different story. Here, the group can knowledgeably digest the facts required to fully understand all of PVC's facets, including its environmental impact.

With that premise in mind, IMM set out to uncover both sides of the controversy over PVC's alleged role in releasing dioxin to the environment. As with most issues in life, we found that there are quite a few gray - make that light green - areas in the fracas surrounding vinyl.

Forest Green Defined

Defining the controversy over PVC's environmental impact is relatively simple, especially compared to resolving it. Essentially, environmentalists contend that the significant amount of chlorine inherent in vinyl's manufacture and released upon its combustion is a primary contributor to dioxin in the soil and air. Chemically speaking, during the combustion process, chlorine can combine with organic matter to form dioxin. Dioxins, according to the Chlorine Chemistry Council, are a family of 75 solid chemical compounds, both colorless and odorless, based on chlorine, hydrogen, and oxygen. These compounds do not dissolve readily in water, but are highly soluble in fatty substances and organic matter.

An EPA study of laboratory animals given high doses of the most toxic form of dioxin - 2,3,7,8-TCDD - concluded that this form may cause cancer in humans. But the carcinogenic properties of this and other forms of dioxin are still under debate among scientists. For example, the EPA currently lists an ADI (allowable daily intake) for TCDD as .01 picograms (pg) (1 x 10-14g) per kg of body weight per day. At this dosage, the calculated cancer risk would be 1 in 1 million. By comparison, the World Health Organization sets that level at 10 pg (1 x 10-11g).

Black-and-White World?

Just as there are shades of gray in life, so there are shades of green in the PVC controversy. D'Lane Wisner, manager of environmental solutions for PVC manufacturer Geon (Avon Lake, OH) states that vinyl is half chlorine, and points out that nearly all plastics use chlorine in some way. "Remember also that 60 percent of all chemistry involves chlorine, including products used in water purification systems," he says. During a recent Geon seminar, Wisner cited an example: "The government of Peru decided to stop chlorinating the water supply several years ago in an attempt to prevent chlorine exposure. The result was 20,000 deaths from cholera, malaria, and other diseases before Peruvian officials did a quick about-face, returning chlorine to the country's water.

Uses for PVC range from computer housings to appliances to toys. It is recyclable, offering up to eight heat histories without property loss. Although it has been maligned recently by environmental advocates, PVC supporters and manufacturers contend that vinyl provides us with both function and environmental friendliness.

Whether or not dioxin is carcinogenic, a 1996 study points to the fact that environmental dioxin is on the decline. At the same time, PVC usage and manufacture is climbing. Researchers from both Europe and the U.S. measured dioxin in lake sediments, going layer by layer to determine the age of the deposit. They determined that around 1960, dioxin deposits (measured in pg/sq cm/year) peaked at about 35. Sediments from 1996 show dioxin at about 10. In comparison, vinyl production measured 2.5 billion lb annually in 1960 while reaching almost 13 billion lb last year. Groups such as the Vinyl Institute and Chlorine Chemistry Council assert that if PVC was directly responsible for dioxin in the environment, the study would have shown a direct correlation.

On the flip side, Greenpeace cites a study from 1984 that found an abrupt increase in dioxin concentrations in lake sediment after 1940. This study found agreement between the production of chloro-organic compounds and the level of deposited dioxin.

Study Wars

As you may have already surmised, each side in the vinyl debate fortifies its opinions by performing scientific research, compiling the results into massive studies. On the environmental side, Greenpeace most recently published "PVC The Poison Plastic." Trade organizations point to the 1995 study conducted by the American Society of Mechanical Engineers and authored by scientists Rigo, Chandler, and Lanier.

Briefly, the Greenpeace study concluded with recommendations to decrease chlorine-containing vinyl as the primary method of reducing dioxin. In the ASME study, researchers found that the production of dioxin had no correlation to the amount of PVC or chlorine in the feedstream. Rather, they concluded, the presence of dioxin in stack gases depended upon combustion temperature and incinerator design and operation.

While Greenpeace acknowledged that facility design, operating conditions, and catalysts also contribute to dioxin formation, the group attempted to discredit Rigo et al in the report, "Chlorine and Dioxin." But again, related research failed to find positive correlation between chlorine in the feed and dioxin in the stack gases in more than 80 percent of the municipal incinerators examined.

The Burning Question

These and other studies point to the central issue in the PVC controversy: what really happens when it is burned in an incinerator? In summary, environmentalists contend that dioxin is formed due to the heavy concentration of chlorine from PVC in the waste stream. Trade organizations point out that any incinerator, whether it contains a high concentration of PVC or not, will emit dioxins if the temperature of incineration is below 2000F and if the design and operation are shoddy. Another problem, these groups say, is that chlorine can be introduced from many sources, both natural and synthetic.

Now a word from the neutral corner: The Environmental Protection Agency considers incineration one of the viable alternatives for handling solid waste. In a report entitled "An Agenda for Action," the EPA's Municipal Solid Waste Task Force advocates developing environmentally safe incineration facilities as part of an overall plan to reduce solid waste that also includes recycling, reuse, and reduction. Now for the burning question - where are these incinerators going to be located? One of the problems facing implementation of this option is the Nimby syndrome, a.k.a. "not in my back yard." It is difficult to convince communities of environmental safety when visions of dioxin-emitting incinerators still exist. Currently, less than 10 percent of unrecycled waste in the U.S. is incinerated; the remainder goes to landfills.

Other countries offer a contrasting perspective on this issue. Sweden, for example, one of the only countries with specific dioxin regulations, sends 55 percent of all solid waste to incinerators, where it becomes fuel for energy plants. Twelve years ago, the country conducted a one-year study of air emissions, concluding that modern incinerator technologies such as electrostatic precipitators, lime scrubbers, and fabric filters could reduce harmful emissions by more than 95 percent. Solid waste-to-energy conversion also runs successfully in Japan (46 percent) and Germany (35 percent).

Environment Canada, a government agency, also offered input on this question. It conducted a study in which two pilot air-pollution control systems were connected to a mass-burning incinerator in Quebec City that contained a significant amount of plastic in the feedstream. Testing showed that higher flue gas temperatures - 1800 to 2200F - removed 95 percent of all pollutants.

A rebuttal to these findings from environmentalists comes from the EPA in Denmark. A 1993 Danish study found that "doubling the PVC content of an incinerator's wastefeed increases dioxin emissions by 32 percent," according to Greenpeace's Thornton. He also reports that the German EPA found that combustion of chlorinated wastes containing plastics and other chemicals produced higher dioxin concentrations in ash residues than combustion of chloride-containing but chlorine-free paper, wood, cotton, or wool.

Recycling: Just Say Yes

Recycling could represent a mutually agreeable solution to the PVC controversy. Unfortunately, recycling vinyl and other plastic products generally remains yet another solid-waste alternative that causes government, industry, and environmental advocacy groups to differ. That's because efforts to create viable recycling infrastructures have stalled. Government involvement is nil at present, and while a few notable companies are operating profitably, there are almost no economic incentives to set up the collection, cleaning, and separating systems necessary to generate revenue. Without a thriving industry, the hope of successfully and economically recycling PVC or any thermoplastic remains dim.

Compare this to the bright outlook on PVC's ability to be recycled. Geon's Wisner explains: "Vinyl retains its properties upon remelting - on average, it can see eight heat histories before significant property losses occur. Also, the end-use applications for recycled PVC are numerous. When recycling becomes widespread, vinyl will be one of its star performers." - Michelle Maniscalco