Uranium tailings puzzle Muskie
Chemist Li Two loops, 188 amino acids
responds only to growth hormones from primates, which are not so readily available as bovine or sheep hormones. (Rats, however, respond to growth hormones from all mammals.) Dr. Li and his co-workers isolated the first growth hormone (from cattle) in 1944. They isolated human growth hormone for the first time in 1956. Work on the structure of the latter began soon after isolation. In 1964, the Berkeley scientists separated clusters of human growth hormone molecules into single chains. They found that the molecular weight of the chain is 21,500. They determined its amino acid sequence by standard protein chemistry methods. Enzymes break the chain into fragments containing from five to 10 amino acids each. These enzymes—trypsin, chymotrypsin, and pepsin—each attack different amino acids and produce different fragments. The fragments are purified on ionexchange resin columns, then analyzed for kinds and number of amino acids with an automatic amino acid analyzer. The sequence of the amino acids in each fragment is determined by the phenyl isothiocyanate method. The fragments can then be assembled into several possible complete structures. The correct one was chosen by splitting the molecule into four large fragments with cyanogen bromide and determining the sequence of these fragments. Laboratory synthesis of the entire chain would be extremely difficult, Dr. Li says. But knowledge of the structure paves the way for learning which part of the molecule is responsible for which biological activity. Evidence from the Berkeley laboratory already shows that less than half the molecule may be needed to promote growth. 18 C&EN MAY 16, 1966
Sen. Muskie's Special Subcommittee on Air and Water Pollution is trying to answer two questions on water pollution from radioactive materials: Do radioactive materials in piles of tailings from shutdown uranium mills in the Colorado River basin threaten seriously to contaminate the river and its tributaries? What responsibility, if any, does the Federal Government have to see that these piles are maintained in a safe condition? At committee hearings both the Atomic Energy Commission and the Federal Water Pollution Control Administration (currently a unit of the Department of Health, Education, and Welfare) agreed that at present there is no serious radioactive contamination in the river basin. In fact, the concentration of radium-226 (the most likely contaminant) in the streams is no more than one third of the level regarded as safe. However, AEC and FWPCA disagreed sharply on the possibility of future contamination from the piles of tailings. Most of the radioactivity left in the tailings is very long lived. For example, radium-226 has a half life of 1620 years and thorium-230 has a half life of 80,000 years. At most of the mill sites FWPCA says, the piles are subject to slow erosion by wind or water to nearby streams. While this process will not produce large-scale contamination, FWPCA says, "There is potential for small continuous amounts of radioactivity to be leached to the streams over a long period of time." FWPCA recommends that interim measures (designed to prevent spread of radioactive materials for 10 to 20
years) be started without delay. These measures include covering the piles of tailings with dirt or a petroleum stabilizer, seeding, and building dikes to protect the piles from river erosion. FWPCA also wants discussions to be held leading to binding agreements regarding long-term public and private responsibilities for adequate maintenance of the tailings piles. Responsibility should be fixed now, FWPCA says, while the owners of shutdown plants can be readily identified. Otherwise, if contamination becomes a problem in the future, it may be impossible to determine who is responsible for the damage. AEC does not agree that the piles represent a radiation hazard. Its studies show that people in the vicinity of the piles would be exposed to only a small fraction of the concentrations of radioactivity allowable by applicable standards. AEC also rejects the speculation that the piles may become hazardous at some future time. "At the present time we find it difficult to conceive of any mechanism whereby the radioactive material which is now so widely dispersed could become so concentrated as to exceed current applicable standards for protection against radiation." Regardless of the situation, AEC says it plans to continue its cooperative effort with federal, state, and local authorities as well as with the uranium milling industry to achieve adequate pollution control. Sen. Edmund Muskie (D.-Me.) says his subcommittee will not come to any quick conclusions but will try to develop an insight into the public and private responsibilities for these radioactive wastes. "We don't want to develop any unnecessary fears where hazards may not exist; what we want is to determine the ultimate responsibility for any future problems that might arise," he added.
GC scale-up patent issues
• Uranium processing plants
Dots show uranium mills in four-state area where tailings piles could lead to radioactive contamination of Colorado River and its tributaries
Plant-scale gas chromatography—a technology building up rapidly at Abcor, Inc., Cambridge, Mass.—has now been buttressed by a patent issued last week to Dr. Raymond Baddour, professor of chemical engineering at MIT and cofounder of Abcor. The patent (U.S. 3,250,058) provides broad coverage of methods and apparatus involving use of column internals in scaling u p chromatographic columns to large sizes. Abcor, an engineering company specializing in advanced separations technology, has for some time been developing the technology of plantscale gas chromatography (C&EN,
