Backyard burning is recipe for dioxin.Prompted in large part by concern over dioxin dioxin Aromatic compound, any of a group of contaminants produced in making herbicides (e.g., Agent Orange), disinfectants, and other agents. Their basic chemical structure consists of two benzene rings connected by a pair of oxygen atoms; when substituents on the rings are emissions, cities around the globe have been tightening regulations on municipal incinerators. Largely ignored have been rural households that burn their garbage in a barrel out back. A new federal study now indicates that just a handful of such fires can spew as much dioxin as a large municipal incinerator does. The results also reveal that per pound of trash burned, avid recyclers spew the most dioxins. These toxicants, last year formally designated human carcinogens Carcinogens Substances in the environment that cause cancer, presumably by inducing mutations, with prolonged exposure. Mentioned in: Colon Cancer, Rectal Cancer (SN: 5/15/99, p. 309), are slated to be banned from production, even accidental, under a pair of developing United Nations treaties (SN: 7/4/98, p. 6). Trash burning is policed at state and local levels. In recent years, many regulators have called an Environmental Protection Agency Environmental Protection Agency (EPA), independent agency of the U.S. government, with headquarters in Washington, D.C. It was established in 1970 to reduce and control air and water pollution, noise pollution, and radiation and to ensure the safe handling and hotline requesting data on pollution emitted by the open burning of trash. Two studies had examined burning but had yielded few reliable data, notes Paul M. Lemieux, a chemical engineer who led the new testing by EPA EPA eicosapentaenoic acid. EPA abbr. eicosapentaenoic acid EPA, n.pr See acid, eicosapentaenoic. EPA, n. at its lab in Research Triangle Park Research Triangle Park, research, business, medical, and educational complex situated in central North Carolina. It has an area of 6,900 acres (2,795 hectares) and is 8 × 2 mi (13 × 3 km) in size. Named for the triangle formed by Duke Univ. , N.C. His team collaborated with New York New York, state, United States New York, Middle Atlantic state of the United States. It is bordered by Vermont, Massachusetts, Connecticut, and the Atlantic Ocean (E), New Jersey and Pennsylvania (S), Lakes Erie and Ontario and the Canadian province of officials who had characterized the trash generated by households that did and didn't avidly recycle. The EPA scientists then compiled equal-weight batches of trash simulating those two waste streams. To imitate the typical practice, Lemieux's team burned trash in 55-gallon barrels with ventilation holes punched near the bottom. On average, burning each kilogram kilogram, abbr. kg, fundamental unit of mass in the metric system, defined as the mass of the International Prototype Kilogram, a platinum-iridium cylinder kept at Sèvres, France, near Paris. of a recyclers' trash created 264 micrograms of dioxins, 44 times more than did an equivalent quantity of trash from nonrecycling households. Lemieux credits the difference to the higher proportion of chlorine and metals in the recyclers' trash--key ingredients in the recipe for cooking up dioxins. In fact, it would take only two to three avid recyclers burning 1.5 kg of trash on any given day to match the daily dioxin output of a well-run municipal incinerator serving the needs of up to 120,000 households, Lemieux and his colleagues observe in the Feb. 1 ENVIRONMENTAL SCIENCE & TECHNOLOGY. Charged with tallying U.S. dioxin data, David H. Cleverly of the EPA in Washington, D.C., has applied Lemieux's data to a rough estimate of the U.S. households not subject to bans on residential burning. Backyard burning, he speculates, might annually "add 800 grams [of dioxins] to our national inventory, which is now about 3,000 grams from all sources. So it could, potentially, be a big deal." Lemieux's data also "imply we should be thinking about what's in the waste stream that is causing dioxins to form rather than just trying to manage municipal incinerators to form less dioxin," says environmental scientist Valerie M. Thomas of Princeton University Princeton University, at Princeton, N.J.; coeducational; chartered 1746, opened 1747, rechartered 1748, called the College of New Jersey until 1896. Schools and Research Facilities . Chemist Pat Costner of Greenpeace International in Eureka Springs, Ark., agrees. Since creating dioxins requires chlorine, she argues, "we should move away from chlorine-containing materials"--such as the polyvinyl chloride polyvinyl chloride (PVC), thermoplastic that is a polymer of vinyl chloride. Resins of polyvinyl chloride are hard, but with the addition of plasticizers a flexible, elastic plastic can be made. plastic that Lemieux identified as the likely primary source of the dioxin in the trash he burned. |
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