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LETTERS Atmospheric mixing Dear Sir: I was much interested in this news story ( E S & T , January 1980, p 15) since I have been trying to ascertain the origin of ground-level ozone observed here in southern California during S a n t a Ana wind conditions. T h e upper left diagram on p 16 is unfortunately mislabeled; some readers may notice that this diagram o f a typical ozone profile shows maximum ozone concentrations of 20 pphm while the lower diagram shows values as high as 40 pphm well below the ozonosphere. This may have arisen through a mistranslation of units from those customary a m o n g meteorologists: cm-atm of ozone a t N T P / k m . Manabe and Wetherald, for example, in J. of the Atmospheric Sciences (1967, 24, 241) show a profile with these units as the abscissa. I n his book “Fundamentals of Air Pollution,” Williamson ( I 973) cites this paper as the source for a n ozone profile, but he has labeled the abscissa in ppb. He apparently ignored t h e fact that the ozone concentration is corrected to sea level ( N T P probably the same as S T P ) while km refers to the real thickness of a layer of the upper atmosphere. T h e actual concentration by moles, molecules, or volume is more like 7 or 8 ppm. This may be one of those propagating errors, since it also appears in Seinfeld’s book, “Air Pollution, Physical and Chemical Fundamentals.” Edgar R. Stephens
University of Calif.-Riverside Statewide Air Pollution Research Center Riverside, Calif. 92521
Literature citations Dear Sir: Citation analyses, which attempt to define significant publications in special areas and which subsequently generate lists t h a t become regarded as definitive in those areas, can often be misleading to those seeking a “best list” of the publications in a subject field. Subramanyan and O’Pecko, in their E S & T article (August 1979, p 927-29), have produced such a n analysis. However, their conclusions. which a r e correct for the evidence they have produced, unfortunately present a misleading view of the environmental field. In our company 626
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library (we a r e environmental consultants) there is a vastly different citation and use pattern than what these authors found. Much of the work which we perform may never be cited in conventionally published literature. There are two reasons for this. Work for industrial clients becomes the clients’ property, and only gets into the open literature if a client wishes to have the work published. W o r k on governmentsponsored projects is published in government reports, but such reports a r e not considered to be in the conventional open literature. Such \vork reaches the open literature if our government client agrees to have us publish a paper on the sponsored work. Much of the use to which our library is put is in making available in usable form such government reports. Our people rely heavily on the following journals: Atmospheric Encironment, Encironmental Science and Technology, and Journal of the Air Pollution Control Association, and to a much lesser degree, Science, Analytical Chemistry, American Industrial Hygiene Association Journal, Archices of Encironmental Health, and Journal of Chromatographic Science. W e work in the water, noise, soil, and air pollution areas, but the bulk of the library’s journal activity centers around these first three journals, and the order of use is approximately a s I have listed them. There is nearly constant activity with these journals, especially on the citations accompanying the articles, but this level of usage would never be discernible through the published journal literature. W e experience heavy use of the Federal Register, but again, this usage may never be reflected in citations in published papers. FR may be referred to innumerable times, especially by legal staff in such organizations a s ours, but this fact may not be obvious to journal readers. Another noncited service heavily used, which is not a journal but a periodically updated loose-leaf service, is Encironnient Reporter (published by Bureau of National Affairs, Inc.). It receives extremely heavy use. There a r e probably several other
examples of “invisible citations” (for want of a better name) that are very important but are cited in the report to the client and not seen by the public unless the client makes the report available (as a journal article, conference paper, or through NTIS). Because of our experience with the literature, encouraging the use of Subramanyam and O’Pecko’s list as a representative core journal collection for an environmental library would be inappropriate. Judith A. Doubille
Technical Librarian TRC-Environmental Consultants, Inc. Wethersfield, Conn. 06109
Groundwater Dear Sir: I read with great interest the January issue of ES& T in which Julian Josephson highlights groundwater and its importance to the nation ( E S & T , January 1980, p 38). There is a growing awareness of the importance of groundwater in this country. As Mr. Josephson correctly pointed out in his article, nearly 50% of our nation’s population rely on groundwater for their drinking water supply, and because of its vulnerability, once contaminated, it is virtually lost to the consumer. T h e issue of groundwater contamination is of such importance that the Environmental Protection Agency (EPA) has undertaken a new initiative in developing a comprehensive strategy to protect this vital resource. In developing the overall strategy, E P A intends to involve citizens, state, local and other federal agency officials-an important process to assure cooperation and understanding a t all levels of this endeavor. W h y federal consideration? Since water rights and law generally are ‘‘local’’ in nature this is a valid question. The answer is severalfold: First, groundwater typically does not respect state borders, and contamination of a n underground source in one state may effect the health and well-being of persons of another state. Second, it is necessary to ensure that federal actions d o not contribute to groundwater (continued on page 628)
