LETTERS Citations
Dear Sir: I read belatedly but with interest the article “Environmental Research Journals” by Subramanyam and O‘Pecko ( E S &T , August 1979, p 927). The frequency of citation data in the core list of research journals (Table 2) intrigued us to do a similar study for 1977 for the Journal of the Air Pollution Control .4s.~ociation(JAPCA). We came up with some figures which lead us to believe that journals develop followings not only in readership but, assuming unbiased editorial review, in authorship. For example, in 1977 ES& T was cited 175 times in ES& T while JAPCA was cited only 41 times. Yet in 1977, JAPCA was cited 148 times in JAPCA while E S & T was cited only 42 times. Our data follow: Total references cited: 1576 Journal articles cited: 785 Journal titles
JAPCA Atmospheric Environment
ES& T Ind. Eng. Chem. Fed. Regist. J. Appl. Meteorol. Arch. Environ. Health Am. Ind. Hyg. Assoc. Anal. Chem. Et cetera
Number of times cited
Percent of total journal citations
148 5a
18.8 7.4
42 38 22
5.3 4.9 4.9 2.8
ia
2.3
16
2.0
16
2.0
37
Harold M. Englund Air Pollution Control Association Pittsburgh, Pa. 1521 3 Water chlorination
Dear Sir: In reading the January 1980 issue of Encironmental Science & Technology, I noted on p 21 some comments from my talk at the water chlorination conference in Colorado Springs, Colo. I would like to clarify this material since it does not ade-
quately describe the material presen ted. First, 1 indicated that a little chlorine is always needed at the condenser outlet at the plant where the stud) was conducted, not just usually. It is true that no chlorine was used on one unit for a period of five weeks during the winter months, but I did indicate that this was part of the study and that the condenser became severell fouled during this part of the study (February). We knew it would foul during the summer. but at such low inlet water temperatures (ranging from 3 5 O F to 40 O F during this time of the winter), we did not know for sure that fouling would occur. Second, the quotation regarding TVA’s N P D E S permit requirements is incorrect. It is stated in our plant N P D E S permits that the plant must maintain average free residual chlorine ( F R C ) concentration of no more than 0.2 mg/L or a maximum instantaneous concentration of 0 . 5 m g / L F R C before mixing with any other waste stream. In addition, only one unit may be chlorinated at a time. This permit is not a TVA-imposed requirement, but it is an EPA requirement of TVA. R. D. Moss
Tennessee Valley Authority Chattanooga, Tenn. 37401
Groundwater
Dear Sir: Just a short note to tell you how much we enjoyed the “Safeguards for groundwater” article that appeared in your January 1980 issue on p 3 8 . The discussion of this timely and complex subject was excellent and we, of course, appreciate your mention of our firm. David W. Miller
Geraghty & Miller, Inc. Syosset, N.Y. 11791 Dear Sir: I read with great interest and some dismay your article on “Safeguards for groundwater” ( E S &T , January 1980, p 38). I wish to point out:
( I ) The vast majority of the 1 I O million Americans dependent on groundwater do not obtain their groundwater in the manner shown by the lady on your cover. Submersible pumps are normally used for large volume abstractions, not human muscles. Your photograph is irritatingly misleading. (2) Hydrodynamic dispersion does occur in the subsurface and, although it may be less pronounced than in rivers, it is an important mechanism in the dilution of contaminants both in soils and in sand and gravel and sedimentary rock aquifers. Methods to quantify contaminant dispersion in groundwater have been developed and applied in the U S . , Canada, West Germany, Britain, France, and Israel. (3) It is simply untrue that contaminants which enter a “groundwater horizon have virtually no natural antidotes.” As you point out later in your article, adsorption reactions limit the mobility and concentration of contaminants. Furthermore, heavy metals may be precipitated as oxides, carbonates, or sulfides, and organic compounds may be reduced to simpler nontoxic forms with the aid of microbial catalysis. While these mechanisms may not everywhere maintain contaminant levels below drinking water limits, they are effective in varying degrees in controlling the mobility and concentration of contaminants i n groundwater flow systems. Understanding such mechanisms will allow waste-disposal sites to be chosen on the basis of the waste-retention properties of local earth materials and watersupply wells to be sited beyond the zone of influence of any potentially contaminating activities. (4) In order to summarize European and North American studies of groundwater pollution and the measures taken for its prevention, U N ESCO will publish in late 1980 a report entitled “Aquifer Contaniination and Protection.” Richard E. Jackson
Environment Canada
Ottawa, Ontario K I A 0E7 Volume 14, Number 4,April 1980
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