on aquatic life, wildlife, and humans," and to develop a strategy to reduce use of those substances. "The committee's bill has been developed in close cooperation with the Adnrrinistration/' notes Sen. Max Baucus (D.Mont.), chairman of the parent committee, which will mark up the bill later this month. 'The old, so-called commandand-control approaches that worked to control pollution from factory and sewer pipes may not work ... when we're talking about the cumulative effects of small amounts of toxic substances that accumulate up through the food chain/' However, the bill takes a more traditional approach in many areas. For example, it tightens EPA's control of chemicals discharged from industrial facilities, allows the agency to develop tougher effluent guidelines by mandating changes in manufacturing processes, and increases regulation of effluents that must be treated before release to publicly owned treatment works (POTWs). Industry has been allowed to dis-
charge into POTWs wastewaters that have been pretreated to eliminate most, if not all, pollutants—as long as a municipal system can comply with its permit. The proposed law requires manufacturers and others to pretreat their effluent to the same standard used for direct dumping into lakes and rivers. Related to this is a provision to eliminate the domestic sewage exclusion (DSE), which allows pretreated industrial wastes to be mixed with sewage and sent to POTWs. This effectively avoids some conflicts between the Clean Water Act and the Resource Conservation & Recovery Act over toxic chemical regulation. Industry fears that removing the DSE would result in costly duplication of controls by the two laws. In addition, the proposed law increases EPA authority over indirect discharges of pollutants, increases criminal penalties for initial violation of the law to up to five years in prison, and doubles penalties for repeat offenders. Bette Hileman, David Hanson
Electric fields alter lipid membrane structure Chemists at Stanford University have shown that relatively modest electric fields can alter the structure of lipid monolayers that are models of biological membranes. Their research [Science, 263, 655 (1994)] suggests a mechanism by which electromagnetic fields (EMFs) could affect biological systems. Such a mechanism has been lacking until now in the debate over possible EMF health effects (C&EN, Jan. 31, page 19). "This does not prove that external electric fields have a deleterious effect on cell membranes, but it suggests that they might have such effects/' points out chemistry professor Harden M. McConnell, who directed the study. In work supported by the National Science Foundation, McConnell and postdoctoral fellows Ka Yee C. Lee and Jurgen F. Klinger studied a binary mixture of dihydrocholesterol (DChol) and dimyristoylphosphatidylcholine (DMPC). Their experiments are conceptually simple: They create a monolayer of a mixture of DChol and DMPC on water in a glass dish. A tungsten wire insulated by a glass capillary pokes through the monolayer. Application of an electric potential between the water and the wire results in an inhomogeneous electric field across
the monolayer. The group uses fluorescence microscopy to monitor changes in the monolayer. McConnell and coworkers varied the composition of the monolayer and surface pressure to investigate the monolayer's response to an electric field in different regions of the phase diagram of the DChol-DMPC system. Binary mixtures such as those the group is studying are characterized by a critical pressure, above which the two liquids are miscible in all proportions. Below the critical pressure, there can be either one or two phases of the mixture, depending on composition and pressure. The critical pressure is related to the critical temperature, Tc. McConnell says that application of an electric field at pressures below the critical pressure produces a liquid-liquid phase separation in an otherwise homogeneous monolayer. At pressures slightly above the critical pressure, an electric field produces a large concentration gradient in the monolayer without phase separation. The temperature at which an organism grows affects the lipid makeup of its membranes, McConnell notes. This "growth temperature,,—98.6 °F for humans—is often just above the temperature that triggers the onset of phase separation,
and thus may be close to Tc. This suggests to McConnell that even weak electric fields could have a significant effect on the structure of biological membranes. Nevertheless, he tells C&EN, 'If I had to make a bet as to whether weak electromagnetic radiation had a significant effect on animals, I would bet against it. However, if I were told, 'yes, there definitely is an effect on animals/ these results are something I would think very seriously about in trying to develop a research program to discover the mechanism/, Rudy Baum
Top researchers seek to shape science policy More than 200 top U.S. research figures—most of them dispirited during the past year over fears of being politically forgotten—gathered at a hastily called meeting in Washington, D.C., last week to help the Clinton Administration write a national science policy for drastically changing times. But there was another agenda perhaps even more important to them. They wanted to know that the Administration and Congress love them for what they do. The verdict: Yes, they are loved. Such officials as Vice President Al Gore and Sen. Barbara A. Mikulski (D.-Md.) said so. The meeting, held at the National Academy of Sciences, was unusual in that it was the Administration's own idea. White House science adviser John H. Gibbons wants to draft a major na-
Mikulski: new paradigm is emerging FEBRUARY 7,1994 C&EN
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