NEWS OF THE WEEK
EPA ALLOWS NOPERMIT SPRAYING PESTICIDES: Industry says exemption will provide regulatory certainty
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HE AGRICULTURAL CHEMICALS industry says it welcomes a decision by the Environmental Protection Agency that will allow pesticides to be applied by farmers, ranchers, and public health officials over and near bodies of water without obtaining a permit under the Clean Water Act. But pesticide manufacturers also maintain that the scope of the final rule, issued on Nov. 21, should be broader. "EPA's action clarifies two important situations where a permit will not be needed before applying pesticides, but it only applies to aquatic uses and forest canopy applications," says Jay J. Vroom, president and chief executive officer of CropLife America, an industry trade group. Under the new regulation, pesticides can be applied directly into water or sprayed nearby without a pollution permit if the application is needed to control aquatic weeds, mosquitoes, or other pests. EPA says the measure clarifies that permits are
HOW POLONIUM POISONS TOXICOLOGY: 210Po carpet bombs cells with damaging a-particles
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HE POLONIUM-210 POISONING of former Soviet spy Alexander Litvinenko has health physicists dusting off Cold War-era tomes on the biological effects of radioactive isotopes. Data are scarce, especially for human exposure to the isotope, but scientists still have a good idea of how polonium may have led to Litvinenko's death on Nov. 23,22 days after his alleged poisoning in London. 21 °Po, once used in triggers for fission bombs, is an a-particle emitter with a half-life of 138 days. It decays into stable 2o6Pb by spitting out an a-particle—a helium nucleus—with 5.3 MeV of energy. That's a million times the energy of a typical chemical bond. Even so, a-particles are readily stopped by a single sheet of paper, so 210Po generally becomes dangerous only if it gets inside the body. If Litvinenko ingested even 1 ug of 21°Po, perhaps as a citrate or chloride salt, roughly 3 quadrillion atoms of the isotope would have entered his system, enough potentially for tens or even hundreds of 210Po atoms to reach
not required as long as the pesticides are sprayed in compliance with the Federal Insecticide, Fungicide & Rodenticide Act (FIFRA), the federal statute governing the registration and application of pesticides. Vroom says the rule removes some ambiguity in the permit question for public health officials and a few other pesticide users and partially closes the door on nuisance lawsuits. "For the rule to be comprehensive, it should apply to all applications of pesticides, which would encompass production agricultural uses of crop protection products and other essential applications of pesticides," Vroom states. Environmental activists, however, charge the exemption will lead to more toxic chemicals getting into the nation's waterways. "EPA's action allows the weaker and more generalized standards under FIFRA to trump the more stringent Clean Water Act standards," says Jay Feldman, executive director of Beyond Pesticides, a Washington, D.C.-based activist group. The water pollution law, he explains, uses a healthbased standard to protect waterways and requires permits when chemicals are directly deposited into rivers, lakes, and streams. FIFRA, in contrast, uses a subjective risk assessment with no attention to the safest alternative. "Studies suggest that more protection is needed from pesticides, not less," Feldman asserts.-GLENN HESS
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every cell of his body. Even as he began excreting the poison, most of the polonium atoms would have insinuated themselves into cells by associating with proteins. From those perches, the radioactive nuclei would have shot out a-particles that wreak biochemical carnage. Wherever these a-particles go, 209, they deposit a huge amount of energy in a tiny region, says radiation researcher Roger W. Howell of the University of Medicine & Dentistry of New Jersey, in Newark. As each a-particle cuts a path through a several-cell distance, Howell and others say, it leaves a devastating trail of ionization and radical formation, destroying proteins and severing Polonium DNA along the way. Antistatic foils Litvinenko died just a few weeks following his poilike the one shown soning probably because the a-particles decimated the contain tiny especially fragile stem cells in his bone marrow that are amounts ofarequired for the constant proliferation of red blood cells emitting210Po. and key immune system cells, explains veteran radiation scientist Albert L. Wiley Jr. of the Radiation Emergency Assistance Center/Training Site, in Oak Ridge, Tenn. It will take sleuthing by detectives and a detailed autopsy report to determine more precisely what happened before, during, and after Litvinenko's poisoning, Wileynotes.-IVAN AMATO
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DECEMBER 4, 2006
