LETTERS Pollutants and human reproduction Dear Sir: In reference to the article “The effect of environmental pollutants on human reproduction, including birth defects,” (ES&T , June 1981, p. 626), we find portions of the paper relative to mercury to be incorrect and grossly misleading in several respects. In Table 1, mercury is listed as one of the teratogenic metals. This writer checked one of the references associated with this listing and found that there was no mention in the reference regarding teratogenicity of metallic mercury; rather, the reference discussed methyl mercury. Based on the fetal effects for mercury listed in Table 1, we suspect that most of the references cited refer to alkyl mercury compounds and not to elemental mercury. In the last paragraph, middle column of p. 635, the authors state, “An effect of mercury and methyl mercury in decreasing male fertility is well known (37).” Ref. 37 is given as Doull, J.; Klaassen, C.; Amdur, M. “Toxicology,” 2nd ed.; MacMillan Publishing Co., Inc.: New York, 1980, p. 96. Neither mercury nor methyl mercury is mentioned on p. 96 of the reference. In fact, the authors of this textbook do a good job in emphasizing the differences in the toxicology of mercury and alkyl mercury compounds. We find no mention at all of the “well-known” effect of either mercury or methyl mercury on male fertility in any of the text on mercury in this reference. At the top of p. 635 in heavy type, set apart from the main text, is the statement, “No other compound has been involved in more poisoning incidents or claimed more victims than mercury. At Minamata, Japan, 700 cases of human poisoning were recorded with a 38% mortality rate. . . . The lack of maternal symptoms attests to the ease with which methyl mercury crosses the human placenta.” The first statement is false since mercury obviously is not a compound. And the fact of the matter is that the Minamata incident resulted from direct discharge of methyl mercury-not metallic mercury-from an industrial source. Moreover, there is little doubt that 1112
EnvironmentalScience & Technology
carbon compounds have caused more poisoning incidents and have claimed more victims than have mercury compounds. However well-meaning the objective of this publication, your failure to properly distinguish the very different toxicity of mercury and alkyl mercury compounds results in a real disservice to the science. Edmund J. Laubusch Chlorine Institute, Inc. New York, N.Y. 10173
Author’s response Dear Sir: The letter by Mr. Laubusch points out some errors in our list of references and some ambiguous wording (in the section of our article dealing with mercury-related teratogenesis) that has apparently led to some confusion. Underlying all the points in Mr. Laubusch’s letter is a disbelief that metallic mercury or inorganic mercury compounds can be associated with teratogenic effects, abortion, or infertility. Unfortunately, Mr. Laubusch interpreted the title of Table 1 in a narrow sense. Perhaps, instead of “Teratogenic metals,” we should have used the caption “Teratogenic effects associated with metal-containing compounds.” However we, as well as the referee, thought this was obvious in the table as well as in the text (p. 634, paragraph 1). Although Mr. Laubusch read only one of the listed references in Table 1, I would like to point out that inorganic forms of mercury have been implicated in animal systems with abortions (Ref. 47: HgC12); also, Gale and Ferm have demonstrated both fetotoxicity and birth defects in hamsters by exposure to mercuric acetate (Ref. 103). Toxic effects to the human fetus have been documented only with alkyl mercury compounds, mainly methyl mercury. What effects maternal exposure to metallic mercury or inorganic mercury compounds have on the human fetus are unknown. Cleg (Ref. 4 7 ) cites experimental data from mammals to show that transplacental transfer of mercury compounds decreases in the order: methyl > phenyl > inorganic. However, he documents that inorganic mercury is detectable in
the fetal bloodstream. It has been demonstrated that inorganic mercury exerts a deleterious effect on the hamster fetus, but can it also in other mammals? The answer is not known. Also, an interesting statement by Doull (Ref. 37, p. 649) states that methylation of mercury can take place in man (by bacteria in the gut?). If this is so, can inorganic mercury be organified in man to more easily cross the placenta to exert a toxic effect? Little is known about this subject at present. Mr. Laubusch takes offense at ,a statement relating to the number of mercury compound exposures that have led to fetal injury. He has misinterpreted the statement. The article deals specifically with chemical-related birth defects and reproductive failure, not toxicology in general. Can he name one organic compound which has caused more fetal injuries? Three compounds easily come to mind: 1 ) Thalidomide was implicated with 10 000 cases in West Germany; however, this drug, used for therapeutic reasons, is not an environmental pollutant, and therefore was not included in this article. 2) The PCB poisoning incident in Japan involved 13 infants. 3) A case can only be made for diethylstilbestrol, which was a contaminant of beef and poultry. However, no one knows the true number of exposed individuals who ate the meat, or its effect on offspring. The most common effect would be vaginal adenosis, which heals in time via squamous metaplasia. Many would therefore not regard this effect as teratogenic. The contention that methyl mercury itself was dumped into Minimata Bay is false, although even textbooks such as Doull’s is ambiguous on the subject. The factory at Minamata Bay produced nitrogenous fertilizers, vinyl chloride, acetic acid, and H2SO4 (1 ). HgC12 was used as a catalyst in the production of vinyl chloride, and HgS04 in the process for acetaldehyde. Irukayama et al. (2) assayed the seawater from Minimata Bay and confirmed the presence of HgC12, which was predominant, as well as mercuric acetate, vinyl mercuric chloride, HgS04, and metallic mercury. A small amount of organomercurial, also present, was later identified
as methyl mercury. Irukayama postulated both bacterial synthesis of methyl mercury in the sludge (later confirmed) as well as a chemical reaction scheme. Uchida et al. (3) assayed and identified the toxic compound in the shellfish as methylmethyl mercuric sulfide (CH3-HgS-CH3). The organified mercury produced by bacteria was taken up in the aquatic chain and into the shellfish (Hormomya mutabilis). Finally, Mr. Laubusch states he could not find reference to the toxic effect of mercury (metallic) or methyl mercury on male fertility anywhere in Doull’s book (Ref. 37). The reference cited was in error. The correct page is p. 343, as could have been found by consulting the index. Although the toxic effects of metallic lead on male fertility are well known, we agree with Mr. Laubusch that the effects of mercury and methyl mercury are not well known. However, the citation by R. Dixon in Doull’s book stands. Another letter from J. StuartWarner kindly pointed out another error in the references. The correct reference to nickel teratogenesis in rats should be Sunderman et al. ( 4 ) . Ref. 150 by J. Stuart-Warner noted the absence of effects of nickel carbonyl on humans. R. B. Kurzel C. .,I Cetrulo Tufts University School of Medicine Boston, Mass. 02125 References ( I ) Tokuami, H.,et al. K u m a m l o Med. J. 1961,14,47-74.
(2) Irukayama. K., et al. Kumamoto Med. J. 1962, I S . 1-12 1962, IS. 51-68. (3) Uchida, M.,el al. Kumomlo Med. J. 1961, 14, 181-187. (4) Sunderman, F..Jr., et al. Science lW, 203, 550-553.
Cost uf air pollution control
Dear Sir: The feature article, “Minimizing the cost of air pollution control,” by G . R. Cass and G . J. McRae (ES&T, July 1981, pp. 748-757) makes a number of telling points and makes them clearly. Of course, we are still faced with the unfortunate fact of the manifest imperfection of all models. It is all very well to compute a system that leads to no infractions of air quality standards or increments in the computer. However, what is actually enforced is whether infractions occur in the real worldnot invariably the same thing. However, models are in fact improving and, as they do, the generalizations of this paper will still be applicable. I found, however, two disappointments in the final version of the paper.
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The point was certainly made that legislation and regulations to date have set totally unrealistic time tables for the sort of monitoring and modeling program required for rational decisions as to the most cost-effective control steps to be taken. However, the point was probably, not made vigorously enough. At a time when, most probably, a whole cycle of changes may take place in ambient air quality standards, it must be recognized that an adequate program for reaching compliance can easily take three or four years, not the six months to one year frequently allowed. It is not just a matter of grabbing some data and a model and rubbing them together; what is frequently involved is the purchase of an entire new monitoring system, which can frequently involve one or more attempts to get the necessary funds from the elected governing body of the jurisdiction involved, whether a state legislature, a city council, or the Congress. This leads to my second point. It would be very useful to have at least some exemplary figures for the cost of mounting an adequate program of monitoring and modeling. Whether the work is actually done by the staff of an agency or a contractor, the cost is likely to he of the same order of magnitude as present total agency budgets. Speaking as a former state agency official, I can say that an awfully good argument is needed to go before a legislative budget committee to request a doubling of budget, even for a restricted period of time. It would be most helpful to have guidance on how to minimize the a t to the state of minimizing the cost to the polluting industries. It would help to know a typical ratio of cost for an effective planning program to the a t saving for industry. Only when armed with this sort of information-at least for one or two representative cases-can we expect the state or local air pollution officer to be able to stand up to the appropriate budgeting authority to raise the funds for a proper program, and to the faera1 government for time to execute
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Don’t get me wrong. Cass and McRae have done a good piece of work. However, for better or worse it is unlikely to be widely adopted until there are at least some examples of the cost-effectiveness of this approach in comparison with others. James P. M g e Consultant in Atmospheric Chemistry 385 Broadway Boulder, Colo. 80303
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