Document g22Dp3Z5N0OnaRwjJQe1XL5gV

environment xxl r-f~o,tLe-r Safe PCB's possible? 3' . H*dvPn Polychlorinated biphenyls (cell's) arc widely used industrial compounds that have caused increasing con cern lo scientists because of their toxicological similarity to chlorinated hydrocarbon pesticides and their persist ence in nature. Thu major manufacturer of pea's in the United Slides has stringently curtailed their use, but foreign use continues. A University of California, Riverside, researcher says it is possible to alter i*c n's chemically so they will be biodegradable and thus not be persistent in nature. But he adds that more research will have to be done to determine if the altered rat's arc commercially useful and otherwise desirable. Microbiologist Maqsud Ahmed says biodegradation of pen's depends on the position and numbers of chlorine atoms in a rcu molecule.'Reporting at the American Society for Microbiology annua! meeting in Philadel phia, Ahmed stated (hat he and D. .1). Focht deter mined that pure cultures of bacteria isolated from sew age arc capable of breaking.down imsubstitutcd biphenyl and monochloiobiphcnyl molecules byaltaekmg'al'irpar- ticular site of the molecule. If the 'compound'>s'altered by placing a chlorine atom at the :.itc, however, the bac teria no longer can degrade the compound. Further research will aim at determining biodegrodability by the bacteria of a number of rot molecules with diflercnt chlorine atom configurations. Rural air pollutir n The Environmental Protection Agency considers one milligram per cubic meter of urban particulate air pollu tion severe. Two Kansas State University researchers say that the level from dust storms in Midwestern rural areas goes ns high as 15 milligrams. The high level?; occur for as many os 423 hours annually at one research point, Coodland, Knns. The dust levels arc clearly correlated with farming. In Glasgow, Mont., where the researchers say there is little cultivated land in relation to grazing land, there was little dust. Bui in Lubbock, Texas, where the surround ing area is heavily cultivated, there were 47.5 dajs an nually of high levels. The average level of the agricultural dust at the Mid western research sites during dust storms was 4.K5 milli grams per cubic meter. 17aia were from the 1950's, a period of drought, and the two researchers. Lawrence Hagen and Neil P. Woodruff, arc now looking at 1960's data. The agricultural particulates arc larger than urban ones, and likely differ in many other ways. But the re searchers say their findings may justify imposing limits under air pollution laws. Substitute GNW for GNP Sicco S. Mansholi, the new president of the Commis sion of the European Communities, says overemphasis on a growing gross national product is "diabolical" and should be replaced with a new concept, "gross national welfare." He says Europe must take the lead in worldwide ac tion for pollution control, population limitation and the bettering of human life. I Ire United States, faced with domestic political pictures, cannot cany the burden alone, he emphasizes. natal sciences The real thirst quencher Cold water really does quench thirst faster than warm water, but the body may not get as much water as it needs. There is a lag between the time when enough water is consumed and the time when extracellular lluid reaches normal levels (hydration). To prevent e\ec->s intake, sonic mechanism must anticipate hydration and signal the organism to stop drinking. Gregory Knpatos and Richard M. Gold of the Slate University of New York at Cortland deprived rats of water for 23.5 hours and then allowed them to drink at will for half an hour. Water temperature was vailed from J2 degrees C. lo 48 degrees C. They found that the amount of water consumed by the rats increased with temperature to a peak at 36 degrees, the body temperature of rats, and then declined as temperature approached pain thresholds, The researchers suggest in the May 12 Science that rats drink less cool water be cause cooling of the tongue signals satiation. Evolution apparently favored a temperature-based water-intake regulation, say the researchers; in wild animals and primitive man water needs correlate with the temperature of the environment. Trout, heat and ATP Many species of fish are sensitive lo temperature changes. Thermal pollution that raises water tempera ture by only a few degrees may, for example, disrupt the migratory behavior of exposed fish. The Environ mental Protection Agency has recommended that heat added to streams should not raise their temperature moie than 2.8 degrees C., and suggests that migiaiion of salmonids would not be affected by temperatures 20 degrees C. or lower. From studies of stcclhcad trout, W. S. Zaugg. B. L. Adams and L. R. McLain of the Western Fish Nutrition Laboratory of the Bureau of Sport Fisheries and Wild life in Washington conclude that those temperature limits are much too high. In the spring, young trout spawned in the Columbia River undergo adaptive bio chemical and physiological changes and migrate seaward. The rcscachcrs report in the April 28 Scilncl that one of these changes, an increase in adenosine triphos phatase activity, is prevented or reversed if fish arc ex posed to water above 12 degrees C, Fish with diminished adenosine triphosphatase activity die in seawater. Homing pigeons and the lagena How a pigeon released in alien territory finds its way home is unknown, but it has been suggested that cither of tsvo organs, the lagena and the cochlea, may aid na\igation by sensing changes in atmospheric pressuie. Ihc function of the lagena, a well-developed sense organ in the inner car of birds, is unknown. Hans G. Wallraff of the Max-IM.mek Institute for Be havioral Physiology in Scewiesen, Cieiinany, icmntcd both cochleae and lagenac from 14 homing, pie-eons. p;m\'( them with normal birds and released them at two locations 151 kilometers and 159 kilometers from the loft. In both cases, the operated pigeons pci formed as will in finding, the loft as did coniio] pigeons. W.illivff coni hides in the April 19 Naicki. Ni w Bioiogv that v. ha lever the function of the l.igvna is. it does not seem to be isscntiai to homing 3JU HUNS 062349 science news, veil. 101 am y 2o,iCni