5 January 2000
Home sweet toxic home
by Kate Melville
Burning off trash in the backyard is almost a tradition in many countries and aside from the obvious environmental problems there is also the risk of producing major amounts of toxic air pollution.
According to the United States Environmental Protection Agency and the New York State Department of Health, a family of four burning trash in a barrel in their backyard, can potentially put as much dioxin and furan into the air as municipal waste incinerator serving tens of thousands of households. These polychlorinated compounds can be formed simply by burning common household trash at low temperatures. "Open burning of household waste in barrels is potentially one of the largest sources of airborne dioxin and furan emissions in the United States, particularly as EPA standards force major reductions in emissions from municipal and medical waste incinerators," says Paul Lemieux, of the EPA's National Risk Management Research Laboratory.
The EPA study took emission measurements from burning of "typical" household trash in 55-gallon drums, the trash included newspapers, books, magazines, junk mail, cardboard, milk cartons, food waste, various types of plastic, and assorted cans, bottles and jars. No tires, paint, oils, grease, or other household hazardous wastes were included in the burning. Barrel burn results were compared with emission data from a controlled incinerator that exceeded the EPA's dioxin requirements. Using comparable weights of trash, "emissions from open burning were several orders of magnitude higher than for controlled combustion in a municipal waste combustor.
"Recognizing that there are varied wastes and methods of burning, this particular study found that under test conditions, more polychlorinated compounds were emitted from barrel burning than municipal incinerators because of lower incineration temperatures and poor combustion conditions (in barrels)," says Lemieux.
This new study helps solve the mystery of a major discrepancy between the EPA's estimates of dioxin emissions and actual deposition measurements. Emissions of dioxins and furans from burn barrels "may be an important missing link to help close the gap between measured deposition rates and the emissions inventories.
Burning trash in open barrels is banned in most urban areas of the U.S. but are still allowed in many rural areas.
Although dioxins and furans have been shown to damage the health of laboratory animals, direct evidence of the compounds' effects in humans is less clear but still cause for concern, according to Scott Matsen, Ph.D., of the National Institute of Environmental Health Sciences in Research Triangle Park.
"Exposure to certain dioxins has been clearly shown to cause adverse effects in laboratory animals, such as immune dysfunction, cancer, hormonal changes and developmental abnormalities," says Matsen. "Although the available evidence for adverse effects in people is more limited than for laboratory animals, the sum total of the information is cause for concern about the human health hazards of environmental exposure to this class of chemicals."
So it's time to let your rural (and any other neighbours) know that while burning off a few bits of rubbish in the back yard may seem harmless enough, it is pretty bad for the environment and the health of people down wind.