approach that focused on data concerning plant operations, technologies, and so forth to calculate releases. Then they took an "outside-in" approach, measuring soil and water contamination to calculate what emissions level would have caused the contamination. Till predicted that the upcoming studies will be more difficult because they will include chemical releases. Although plant managers kept records on radioactive materials, they were more negligent about chemicals. He also said the fields of chemical and radiological risk assessment will grow closer in the future. Although both use common methodologies and approaches the disciplines make different assumptions about kev issues such as dispersion Till said "T'm willing to bet thprp may hp signifirant Hiffpr that V
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risk numbers and giving the popnlation a better sense of theirto1 ' V"
PAT
PHIBBS
EMFs not a threat at residential levels No "clear, convincing" evidence exists to show that common residential exposures to electromagnetic fields (EMFs) are a threat to human health, according to a new report from the National Research Council. In 1979, researchers found that children living close to high concentrations of electrical wires were 1.5 times more likely to develop leukemia. After reviewing early epidemiological studies, the committee found no evidence that EMFs altered human cell function in common residential settings Neither did they find a case in which "tremendously high" exDosure affected cell DNA, which is believed essential for the initiation of cancer. The report calls for new research to pinpoint the factors that are causing childhood leukemia in children living near power lines and to clarify the relationship between high EMF exposures and breast cancer in animals already exposed to carcinogens. "Possible Health Effects of Exposure to Residential Electric and Magnetic Fields" can be obtained by calling (202) 334-3313.
NEWS TECHNOLOGY Herbicide-resistant soybean plant sprouts opposition to transgenic seeds The first widespread introduction of a herbicide-resistant soybean plant in the United States this fall has stirred resistance to genetically altered seeds by environmental groups and raised questions about the potential risks to the environment. However, many U.S. farmers reported success with the soybean plant, and seed manufacturers said the environmental group's concerns are groundless. Farmers have genetically manipulated plants for decades to improve crop yields. But transgenic plant research has increased over the past decade, with companies like DuPont, Germany's Hoechst AG, and Monsanto pouring resources into seed development. All three companies have introduced seeds that are resistant to the herbicides they produce Monsanto also has introduced potato and cotton seeds resistant to insect pests The chemical producers say the new plants will cut chemical use and emissions from farm eauipment and put less strain on the environment Several environmental groups assert that too little is known about the environmental effects of these plants and urge governments and growers to be more cautious. In October, Greenpeace activists protested by destroying an Iowa test plot of Monsanto's Roundup Ready soybean plants. Two other groups asked EPA to pull the company's registration for its pest-resistant cotton plant Bollgard Bt. The groups warn that transgenic plants could increase growers' reliance on cli.Gmic3.Js as well as induce the spread of the bioeneineered genes to other p l a n t s possibly c a u s i n g s o m e
plants to die out of ecosystems The altered gene that allows Monsanto's Roundup Ready soybean plant to resist the company's popular herbicide Roundup causes growers to use only Roundup to kill weeds in the soybean crop. The benefit to farmers is that because the herbicide can be directly applied to the weeds
The widespread introduction this fall of Monsanto's transgenic soybean plant prompted protests from Greenpeace. Activists sprayed a test plot of the plants near Atlantic, Iowa. (Photo courtesy of Scott 01sen, Greenpeace)
after the soybean plant has sprouted, growers will apply the chemical only once a season, said Karen Marshall, Monsanto spokesperson. EPA prohibits application of a herbicide to a n o n herbicide-resistant seed after the plant has sprouted. But Greenpeace's Beth Fitzgerald argues that farmers might use more of the herbicide, either accidentally or because they worry about crop yield. With repeated exposure, weeds resistant to Roundup will develop, forcing growers to rely on older, possibly more environmentally harmful herbicides, Fitzgerald said. Jack Dekker, weed biologist at Iowa State University, believes that weeds may become resistant to Roundup. "Weeds are survivors," Dekker said. As herbicides are repeatedly applied, eventually new weed strains appear to replace those killed. Although herbicide-resistant weeds themselves don't appear to present an environmental problem in the United States switching to older more environmentally harmful pesticides could add to pollution Dekker said Marshall dismissed environmentalists' worries about increased herbicide use. Roundup has been in use for more than 20 years, and Monsanto has seen no cases of weed resistance. Herbicide use continued on page 528A
VOL.30, NO. 12, 1996/ENVIRONMENTAL SCIENCE & TECHNOLOGY / NEWS • 5 2 7 A
