Document k6roRZKJ8xMR7nmz7Xwxd74R0

;,OM ^ ' SUBJECT : R E tFftE N C E TO D. R. Bishop - A3NB September 27, 1979 Dr. C. F. Callis - B2SA Dr. W. R.' Gaffey - C2SH Mr. F. J. Holzapfel - B2SB Dr. W. J. McCarville - A3NC Dr. F. C. Meyer - C2SH Mr. P. S. Park - E2NJE Mr. R. M. Scott - 1670 Dr. E. Tillman - A2SB Mr. B. J. Wander - C2SA Mr. P. R. Wilkins - 1650 Mr. R. T. Berendt - E2ND Mr. W. D. Crosson - A3NC Mr. W. B. Papageorge - G4WA Mr. J. J. Spano - G4NH F.Y.I., the attached article from the September 24 issue of C&EN is a well-done, comprehensive update on the .dioxin issue. It is worth your time to read it. D R B :ec Attachment Dan R. Bishop CONFIDENTIAL SUBJECT TO PROTECTIVE ORDER. M - 10 i REV. 8 7 7 i i GO 4504 Sci i ?STI*; , lu J Results of several recent studies don't jibe with D ow 's ' contention that dioxins enter environment from combustion; still, agreement is emerging Taking potshots at Dow Chemical's theory that polychlorinated di benzo-p-dioxins are formed by all sorts of combustion processes and axe, therefore, ubiquitous in the environ ment has become a popular sport imong some analytical chemists, specially when there are reporters >res The most recent opportunity or i\ activity, the symposium and jress conference on the chemistry of libenzodioxins and dibenzofurans, ponsored jointly by the divisions of Pesticide Chemistry and of Chemical dealth & Safety (Probationary), had ts share of shooters. But the sessions ilso seemed to show, perhaps for the Irst time, an emerging common ground shared by scientists on all ides of the issue. The issue is Dow's theory, first proposed last Nsvember, that poly chlorinated dibenzo-p-dioxins, diJenzofurans, and biphenyls are ormed in trace amounts in all forms >f combustion. Therefore, they are iot only ubiquitous in the environ ment, but have been there since the idvent of fire. It is only their detecion that is recent, due to advances in inalytical techniques (C&EN, Feb. 2, page 23). The theory has gained so much atention because one of the polychloinated, dibenzo-p-dioxins, the ^.^.S-tetrachloro species (2,3,7,8ICDD), is an extremely toxic comlound that also s a carcinogen and a era i in laboratory animals.-This ?rri1. is a trace contaminant in ne herbicide 2,4,5-trichlorophenox_acetic acid (2,4,5-T) produced by Jow and others. The herbicide is currently under an emergency suspension for many uses from the Environmental Protection Agency because of an alleged associ- ` ation between its use and increased miscarriages in a group of women living near forests that had been sprayed with the herbicide in Alsea, Ore. Detectable levels of 2,3,7,8- TCDD also have been found in fish taken from the Tittabawassee River, which flows by Dow's produc tion plant for the herbicide in Mid land, Mich. Presence of the com pound in fish led Michigan's De partment of Natural Resources to suspect the company of illegally contaminating the river with this compound. So Dow's theory that combustion is a major source of polychlorinated dioxins in the environment is more1 Crummett: complex and expensive than interesting chemistry. If true, it- goes a long way toward absolving the Even these reports may be at least company's product and its manufac partially compatible with Dow's turing process from responsibility for findings. For example, Warren B. contamination of the environment by Crummett, a research scientist with these very toxic compounds. Dow's analytical laboratories, ex Among the potshots the theory re plained that the power plant where ceived at the symposium, two are Dow found dioxins in the stack most prominant: Brenda J. Kimble of emissions was on Dow's Midland fa the Department of Energy's Radio- cility. During the sampling period it biology Laboratory at the University was burning primarily fuel oil, with a of California, Davis, and Michael L. small amount of coal. Various scien Gross, director of the Midwest Center tists at the press conference suggested for Mass Spectrometry at the Uni that possibly the fuel oil, or even the versity of Nebraska, Lincoln, have air in Midland, contains chemical analyzed the smokestack emissions of precursors to the dioxins found in the a coal-fired power plant in California. stack emissions that are not found in They find no T.CDD's in the emis the California power piant. sions, down to their detection level of Crummett criticized the California 0.6 ppt of fly ash. The Dow study study in two ways. He says the sam looked specifically at the smokestack ples were taken from too low in the emissions of a power plant and con smokestacks and that the particulates cluded that this was a source of that were analyzed were primarily dioxins. siliceous, whereas Dow had found Also, David L. Stalling of the U.S. that the dioxins in such emissions Fish & Wildlife Service and associates were associated with carbonaceous analyzed 16 samples of fish and other particulates. aquatic animals for polychlorinated "The particulates we sampled were dibenzofurans and dibenzodioxins. the sdme as those that come out the They found dibenzo-p-dioxins in only top of the smokestack," Kimble says. two samples, both from the Tittaba The Dow study made sweeping claims wassee River. Further, 2,3,7,8-TCDD about power plants being sources of was the most common isomer in these environmental dioxins based on ex samples, an isomer distribution that tremely limited evidence, she says. would not be expected if the source of What she and Gross have shown is the isomer were ordinary combustion. that at least one.important cla>s The most likely explanation, Stalling power plants, those that burn western says, is that the Dow plant is the coal, can be free of dioxin contami source of the isomer found in the nation. fish. The question of the need to have significantly different from tho:-,e of control group animals. Just how important the trace quantities of dioxins that are being found in the environment are iikely to be is a point that was raised fre quently during the symposium. Rappe, Buser, and Stalling ail sc-crned to agree that the polychlorinated di" benzofurans, though less toxic in an absolute sense than the most toxic dioxins, are of more concern because they are present in higher concen trations. They can be formed ly combustion of poE'chlorinated bi phenyls (PCB's), which earlier work has shown are very widespread in the environment. Stalling, along with Donald W. Kuehl of EPA's Duluth, Minn., re search laboratory, Ralph C. Dou gherty of Florida State University, and Rappe, finds polychlorinated precursors present in the material certain kinds of chemicals, such dibenzofurans and naphthalenes in being burned in order to generate combustion presents very little health aquatic animals living in waters that chlorinated dioxins or dibenzofurans hazard. And, like Dow, they think contain PCB's and their breakdown in combustion has become a central that the use of 2,4,5-T is a very much products. The results are somewhat point- of dispute. Something, of less important contributor of dioxins preliminary, since only 16 samples course, has to provide the atoms that to the environment than is combus have been analyzed and, so far, no eventually end up in the'dioxins and tion.- samples have been checked from dibenzofurans. Dow contends, based Even the dioxins that enter the pristine waters. However, animals on its widespread finding of these environment from pesticide use seem taken from the Ohio River and Lake compounds in combustion products, to be much less hazardous than lab Michigan, where contamination that just about anything that will oratory tests would lead ode to be comes from used PCB's, show higher burn can serve as a precursor. Others, lieve, says Capt. Alvin L. Young of the levels and more complex mixtures of particularly Christoffer Rappe of the U.S. Air Force's Occupational & En these compounds than do fish taken :versity of Umea, Sweden, and vironmental Health Laboratory, from the Hudson River, which is s-Rudolf Buser of the Swiss Brooks Air Force Base, Tex. Young contaminated by newly manufac *tueral Research Station, Waden- and his associates have analyzed the tured PCB's but contains low levels of swil, think that synthetic chlorinated soil and animals at Eglin Air Force PCB combustion products. compounds must be present before Base in Florida where 73,000 kg of Rappe and Buser have been combustion will yield chlorinated 2,4,5-T was sprayed between 1962 studying the combustion products of dioxins and dibenzofurans. and 1970. Much of this material con chlorophenols, PCB's, and chlori Here, too, there seems to be some tained much higher levels of nated diphenyl ethers and benzenes. middle ground emerging. Crummett, ^2,3,7,8-TCDD than are now found in All of these compounds can be con for instance, seems to acknowledge The herbicide. verted to polychlorinated dibenzo- that some materials produce more Some 2,3,7;8-TCDD was still dioxins and dibenzofurans in high dioxins when they are burned than do present in soil samples taken in 1978. yield, they find. However, 2.3,7,8- others. He maintains, however, that Concentrations ranged from less than TCDD, the most toxic of the diben- precursor compounds are so wide 10 ppt to 1500 ppt. (Young's analyti zodioxins, is a minor product of spread in the environment that cal method cannot distinguish combustion under the conditions tracking them down via combustion 2.3.7.8- TCDD from all other chlori found in municipal incinerators; data is a task of such complexity and expense as to be infeasible. He re ported two new examples of how widespread 2,3,7,8-TCDD is in the environment. Detectable levels of this compound now have been found in commercial sludge fertilizer made from treated sewage. It also has been detected in the National Bureau of Standards'standard sample of urban particulate matter. Buser and Rappe now say that the synthetic chemical precursors for both dioxins and diobenzofurons can nated diben20-p-dioxins. The con centration he reports is for the com bination of isomers th at includes the 2.3.7.8- TCDD isomer.) The Air Force chemists did not find detectable levels of 2,3,7,8-TCDD in any plants taken from the site. How ever, they Hid find it in nine species of animals, including mammals, birds, fish, ond reptiles. Levels varied from several hundred parts per trillion in the livers of beach mice and mea dowlarks to 12 ppt in the whole bod ies of two kinds of fish. 2,3,7,8-tetrachlorodibenzofuran, the most toxic of this class of compounds, is the major isomer formed under these conditions. PCB's can yield chlorinated dibenzofurans as high as 25%, they find. Nevertheless, except for a few special cases, they do not see even the dibenzofurans as health hazards. They do recommend that poKvi.k,rmated phenolic chemical wastes bo very carefully incinerated in ov-ns that allow for high-temper,-::::re in cineration and long residence !d.. :*> ^und "practically everywhere" in Beach mice, which contained the make sure that toxic prodin - environment at low levels. They highest concentrations of the com destroyed. And halogenated :-K ...**jtain, however, that, except in pound, were singled out for further biphenyls, and diphenyl ' '* special circumstances, such as the study. Eighteen types of tissue from should not be used as finrr,- combustion of chemical wastes or 300 animals were examined for toxic danta because of the high to\.i <:* accidental fires involving stores of effects, but none of the tissues were their combustion products. '* 28 CAEN Sept. 24, 1979