Document m62Rnv2b88XG8yk59o6pL170

21 November 1975 Session Vtll: SUMMARY SESSION John L. Buckley, Ph.D. Session Chairman 467 HONS 205354 SUMMARY OF SESSION I DR. J. G. VOS (Ri|kt Insutuut voor de Volksgezondheid, Bilthoven, The Netherlands). Recent findings on the biological action of PCB's, such as carcino genicity in rodents and the disturbed reproduction in monkeys, greatly increase our concern ol PCB's as a health hazard, In summarizing the papers presented in the session on health affects, one is confronted already in Dr. Kuratsune's paper with the problem ol PCB's and chlorinated dibenzofuran impurities. In the "Yusho" disease, one it struck by the persistence of symptoms present in patients, although thera is a shift in the pattern, a decrease over the years in the skin Easions but a persistence of hypersecretion of Meibomian glands. In "Yusho" patients, increased urinary excretion of 17-ketosteriods was noted, et was an increase in serum triglyceride levels. Changes in the menstrual cycle ware observed in a high per centage of female patients. Mean blood levels in "Yusho" patients were 7 ppb. This level conflicts with the high PCB concentration* in blood of work ers who are occupationally exposed yet who, for the most part, show no indication of adverse effects, A possible explanation for this difference was the relatively high concentration (5,000 ppm on PCB basis) of chlorinated dibenzofuran* (including 2,3,7,B-TCDF) In rice oil. Apparently furans were formed in the PCB during it* use as a heat exchang er, since the level of chlorinated dibenzofuran in Kanechtor KC-400 was approximately 17 ppm. Of particular significance was the relatively high con centration of chlorinated dlbenzofurans versus PCB's in the liver of some patient* who died, when compared with adipose tissue values. Further studies are required to solve the dilamma of the importance of furans in the etiology of "Yusho" disease! and in a wider context, to get information on possible changes in composition or concentrations of chlo rinated dibenzofuran and other contaminants in used PCB's and on their fate in the environment. During the 1971 PCB conference, there was soma concern on a bladder tumor that was found in a rat by Dr. Kimbrough. Now we know that this tumor apparently developed sponteneously. But as we heard from Dr. Kimbrough, in recent studies cer tain PCB mixtures induce tumors in rats and mice. A spectrum of lesions are induced in livers of rats fed 100 ppm Aroclor 1260 for 21 months1 hyper plastic or neoplastic nodules in 80 percent of the treated animals and in none of the controls, and hepatocellular carcinomas in 14 percent of the ex perimental animats and in one out of 173 controls. Metastases were not observed However, hepato cellular carcinomas were not found in the chronic study in rats, as reported by Dr. Calandra A possi ble explanation can be the small number of animals used in this study. Evidently, this question has to be solved. Hyperplastic nodules were seen in 25 to 50 percent of rats fed 100 ppm Aroclor 1242, 1254, or 1260. These three mixtures did not appear to be mutagenic or teratogenic No-effect levels based on 2-year studies in rats and dogs and reproduction studies in rats were 10 ppm. As reported by Dr Allen, adult monkeys and in particular the females are very sensitive to PCB's. Whan Rhesus monkeys were fed 2.5 or 5 ppm Aro clor 1248--that Is, approximately 0.1 or 0.2 mg/kg body waight/day--skin lesions consisting of acne of face and neck, edema, and hair loss developed in tome females already after 2 months, All females exhibited these changes after 6 months, but males were more resistant. Disturbances in reproduction were present in females and not m males Menstrual cycles were irregular within 4 months. The concep tion rate in the 5-ppm group was decreased. Because of resorptions and abortions, the birth rate was re duced and the infant* born were small. Fifty per cent of them died before weaning, showing typical lesions. These effects on reproduction may be due to an estrogen/progesterone imbalance, Female rhesus monkeys on a PCB diet had increased urinary ievels of ketosteriod*. By comparing the reports of Drs. Kuratsune and Allen, one Is struck by the similarity of lesions present in "Yusho" patients and those produced experimentalty in the monkey, with the exception of the effect on serum triglycerides. Both species seem also to be equally sensitive in a quantitative way. Dr, Matthews studied the effect of chlorination on tissue distribution and excretion of PCB isomers in rats. Each of tha PCB's studied was removed rapidly from blood to liver and muscle Redistribu tion to skin and adipose tissue Increased with in creasing chlorine concentration, whereas elimination via urine or feces was highest with the low chlorina ted isomers. After 6 weeks, 85 percent of the 2,4,5,2',4',5'-isomer was still present in adipose tissue and skin, while the residue of 2,4,5,2',5,-iomer was only 5 percent. Significant excretion occurs only after metabolism to polar compounds. The necessary factor could be the pre sence of two adjacent unsubstituted carbon atoms 459 HONS 205355 that facilitate the formation of arene oxide inter mediates, as was also reported by Or. Allen in his Study with the 2,5,2'B'-isomers in the monkey. Or. Ecobichon reported on the influence of position and degree of chlorination of chlorobiphenyl isomers on the hepatic function in the rat. Substitution at the 4 and 4' positions, irrespective of chlorination at other positions, enhanced the activities of endoplasmic reticulum bound enzymes 0- demethylase and aniline hydroxylase. This is probably due to their higher persistence. For en zymes less discretely localized in the liver cell, such es carboxyiesterase and sulfobromophthalein glutathion conjugating enzyme, the position of chlorine atoms appears of lass importance. Purified unsubstituted biphenyl did produce enzyme induc tion, though enhanced effects were noted when one or more chlorine atoms wera present. As can be concluded from the report of Or. Biocca, biologicel effects of symmetrical hexachloroblfenyl isomers differ not only quentitatively but also qualitatively. Such comparative studies are necessary for the ultimate goel--that is, the under standing of the biological effects produced by com plex mixtures that endanger human health, mixtures that ere different from those formulated commer cially. Of the three isomers tested in mice, 3,4,5,3*, 4'.5'-HCB wes most toxic, followed by 2,4,0,2',4',0 'HCB and 2.4.5.2,,4,,5,-HCB, respectively. Liver weights were increased by all three isomars. Severe thymus atrophy and a decrease in or- and y-globulins were produced only by SAS.S^'.B'-HCB. tn a study in chickens, these isomers along with 2,3,4,2 \3',4'-HCB and 2.3,0.2',3',6'-HCB were given at 400 ppm in the diet for 3 weeks. Again, j3,4,5,3',4' ,6' HCB was most toxic and was lathal even at 3 ppm. Chickens exhibited pronounced edema, thy mic involution, and marked liver pathology. How ever, chickens that ware fed 100 ppm died earlier and had only mild.liver pathology. The 2,4,6,2',4' ,6'-HCB was less toxic (no deaths at 400 ppm) but caused marked liver pathology and highest livar weight increase. The toxicological effects of differ qualitatively from tha other HCB isomen studied, and resemble the lesions produced by 2,3,7,8-TCOF. Dr, McKinney reported on metabolism studies of HCB isomers in the chicken using low resolution mass spectrometry. When metabolites were detect ed, the three basic reactions were isomerization. reductive dechlorination, and oxidation with and without chlorine loss. Significant metabolites were not detected in excreta of chickens fed 2,3,4.2'.3', 4' , 3.4,5,3'.4',5\ or 2.3,6,2',3',6'-HCB Meiahydroxylation followed by parahydroxylation ol the same ring are favored processes (or 2,4.5,2',4', 5 -HCB Further oxidation could give quinone, The presence of a metabolite wuh a trihydroxypentachiorobiphenyl structure indicated that dechlorina tion can be concomitant with hydroxylation A dibenzofuran metabolite was not detected. In the case of 2,4,6,2,.4,,6'-HCB. several re action types occurred: dechlorination, isomeri zation, and dibenzofuran formation This isomer had lowest effect on body weight, did not give a high liver residue, but produced most severe liver pethology despite tha dibenzofuran formation. In contrast. 3.4,5.3',4',5'-HCB accumulated most in liver and fat, was most toxic with "furan"-type ef fects. but metabolites were not detected in the ex creta. However, ona has to consider in the case of 2,4,0,2',4',6'-HCB and possibly 3,4,5,3'.4'.5'-HCB the possibility of covalently bound metabolites that may be of toxicological significance A good corre lation, which may have predictive value, was ob served between the retention indices from gas chro matography with the adipose tissue concentration. An exception was the 2,4,0,2',4',0'-tsomer, which had the smallest retention index but relatively high tissue accumulation. The strong ortho effect could be responsible for this discrepancy Dr. Moore reported on tha first toxicity studies with 2.3,7.B-TCDF. Marked thymus atrophy and the presence of edema are seen in chickens dosed dally with 1 pg/kg Oniy mild liver pathology was present et the 5-pg dose level, which produced 100 percent mortality. The LD$0 in guinea pigs eftar a single ora! dose was approximately 7 pgAg body weight. In chicken and gufnea pigs, 2,3,7,8-TCDF is lethal at dose levels that are lass than one order of magnitude higher than that of 2,3,7,8-TCDD and share a number of biological effects. Mica and rats are more resistant to TCDF, A single subcutaneous dose of 6,000 pg/kg did not reduce body weight but gave thymus atrophy and mild liver toxicity in mica No effect was noted in rats intubated with 1,000 pg/kg body weight. Clearly, more research is needed with different chlorinated dibenzofurans isomers in order to assess their health hazards. HONS 205356 SUMMARY DF SESSION It MR. DAVID GARRETT (Environmental Protection Agency, Washington, D.C.J: In Session II, Or. James Mieure, who it research group leader, Mon santo Industrial Chemicals of St. Louis, spoke of PCB's, their properties and mixtures, and presented physical and chemical properties of commercial Aroclor products. Dr, Stephen Safe, Associate and Professor, De partment of Chemistry, University of Guelph, Ontario, presented an overview of analytical identif ication and spectroscopic properties. Key among the points stressed were that sophisticated methods and equipment are available for identification and quan tification of PCB's at extremely low levels. Dr, Robert Durfae, Vice President of Versar, Inc., presented topical information on the manufac ture and uses of Aroclors in the United States and also gave a vivid description of the use of Aroclors in the manufacture of closed electrical systems--in particular, capacitors and transformer products. In addition he presented an overview of PCB's uses in investment casting waxes and the casting process it self was reviewed. Thomas E. Kopp of the Office of Toxic Sub stances in the Environmental Protection Agency re viewed pest, present, and possible future regulatory activities of EPA concerning PCB's in the water environment. He discussed proposed voluntary stan dards being prepared by NEMA, ANSI concerning labeling and safeguards for handling askarals and atkarel-containlng equipment. Than, Mr. Stanton Kleinert, who is Chief of Surveillance for the Wisconsin Department of Natu ral Resources, discussed sources of PCB's in the State of Wisconsin, emphasizing the probable role of intermedia transfer from air to water and describing some possible sources of contamination for food and water, And lastly in this section, Mr. John Hesse, Supervisor of the Toxic Material Unit, Department of Natural Resources in Michigan, described uses of PCB's and losses to the environment of Michigan. Mr. Hesse also emphasized PC8 losses to air and the probably significant transfer of these PCB's into the water medium. Data was presented on PCB concen trations in municipal treatment effluents and sludges, which undoubtedly contributes to the con tinuous cycling in the environment of these persist ent pollutants. . Some of the salient points generally brought forth in the meeting either presented or implied were that PCB losses to air could be an important contributor to the problems we encounter in water. Disposal of PCB's waste to municipal sewage treat ment does not necessarily curtail the cycling and environmental damage from PCB's. And undoubted ly there should be a greater sense of accountability among users of PCB's and a closer control of inven tory. Additionally, there is presently no corrective U.S, authority which could regulate importation of PCB's end PCB-containing products, nor other seri ous environmental contaminants which are not pes ticides, drugs, and the like. And lastly, judging from estimates of PCB's already contaminating tha environment and its in habitants, the task of cleanup is monumental, even if we had proven technology with which to accom plish this task. Thank you. SUMMARY OF SESSION ill DR, IAN C. T. NtSBET: Eleven major points came out In tha course of our session on transport and accu mulation of PCB's in the environment. 1. We know elmost nothing about chlorinated dl- benzofurans, except that they are present in Arodor 1242 and 1254, and wa learned during Session I thet they ere formed in use end they ere formed by metabolism. We know nothing whatsoever about their subsequent behavior in the environment. 2. PCB's themselves remain universally distributed in the environment. Although some releases have been curtailed, othr releases continue. Thase in clude releases from manufacturing, leaks from sup posedly closed systems, scrapping of PCB's manu factured before 1971 and of materials containing them, and use in nonclosed ^systems of material that HONS 205357 i n eithar imported or diverted from other uses. fish, although there is soma human exposure via 3, Surprisingly large quantities of PCB's which other routes, such as milk, meat, and by inhalation , match Aroclor 1254 or 1260 are still being found in in the air. The information from the FDA total diet ' air end :n dry fallout and precipitation. It is difficult program suggested that the dietary exposure of an to account for these quantities in terms of known average adult in the United States is of the order of | past uses, end accordingly we may have to look for 10 micrograms per day, However, an average for a significant current source of air emissions. Perhaps PCB's has little meaning because of the very wide this may be air emissions from transformers, or dis variations in individual consumption of fish and posal of scrap materials from them. enormous variations in tha contamination leveis. 4. Thare is circumstantial evidence that PCB'i that 9. individuals who have a dietary preference for are now trapped in large quantities in sediments in freshwater fish will take in much more than the takas, rivers, and astuarias will remain available for resuspension and will continue to move slowly average--in some cases at least a hundred times as much as the average. Breast-fed infants appear to downstream. Wa do not have any precise infor have extremely high dietary intakes of PCB's, aver mation about their persistence or about the time it will take them to move downstream into the sea, aging about 50 time* higher than that of their mothers on a milligram per kilogram bans. The but we believe that it it to be meesured m years, if breast-fed infant appears to be one of Dr. Kolbye's not decades, 6. Although PCB levels have decreased consider special consumers who is imprudent enough to eat tha tame diet every day. ably In some components of the environment such 10. Monitoring of PCB residues in human fat in tha as terrestrial birds or the mussels collected off United States and Canada shows that tha median California, as yet there is no clear indication of a PCB concentration is of the order of 1 ppm. Again consistent decline in PCB residues in fish. Wa should there are enormous variations, at least a hundred not expect a rapid decline, because of the long re fold variation between the highest level recorded tention time of PCB's in the environment and in and lowest leva) detectable human tissue. 11. Finally, although tetrachlorobiphenyls ara more 6. in addition, many items containing PCB's have easily degraded in the environment than penta- service lives of 10 to 20 years before they are dis chioro- or higher chlorinated compounds, the tetra carded, so thet we ere still experiencing releases of chlorobiphenyls are nevertheless accumulated and materials manufactured before 1971. retained by fish. Accordingly there are significant 7. Because of time lags in response we may not human intakes of tetrechiorobiphenyis, even though yat have reached peak levels in some compartments they are not retained in significant quantities in in the environment, I am thinking here particularly human tissues. Therefore, release of eithar Aroclor of estuaries, where levels of PCB's may continue to 1016 or 1242 into aquatic systems will lead to soma in crease as sediments are transported downstream. human exposure to tetrachlorobiphenyls. 8. Most human exposure to PCB's in tha diet is via n SUMMARY DF SESSION IV DR. DONALD I. MOUNT (Environmental Protection Agency, Duluth, Minnesota): Among and between the birds, mammals, and aquatic organisms there are marked differences in sensitivity to PCB's. Even so. these differences ere not large when compared to species differences found for other pollutants. Like wise, there are differences in tha toxicity of various Arociors and isomers of PCB's that era real but not large. While increasing chlorine content increases tox- icity in warm-blooded animals, increasing chlorine content decreases toxicity of PCB's to aquatic ani mals. This observation is exceedingly important In determining the future actions to be taken on PCB's. Increased chlorine content seems to increase biological half-lifa and bioconcentration in all ani mal groups, but the evidence is not entirely clear cut on this point. To generalize, we can say that in most cases acute lethal toxicity in birds and mammals occurs 462 M0NS 205358 from 10 to 100 ppm In the food, while more sensi tive special may suffer death from 1 to 10 ppm in the food. Concentrations of about 5 ppm in bird eggs produced death. And concentrations of PCB's from .5 to 5 ppm In food produced reproductive or growth effects. For aquatic animals, water concen trations of 10 to 100 micrograms per titer are acute* ly lethal. Concentrations of 1 to 10 micrograms per liter produced chronic reproductive or growth ef* facts and water concentrations of 1 to 10 nano grams per liter (ppt) produced residues of biological or public health significance. Direct uptake from water into aquatic orga nisms is very significant and appears to produce con centration factors on the order of one hundred thousand or more times. Water uptake supplement ed by food intake results m concentration factors of five hundred thousand or more times. The metabolic pathways, biological half-life, and selected isomer concentrations appear to be dif ferent, especially between cold-blooded and warm blooded animals end for various mixtures end iso mers of PCB's, Enzyme systems of poikilotherms are vastly different among the various groups and are also different from the enzyme systems of the homeotherms. Measurable harmful effects of PCB's in the envi ronment on organisms are not abundantly docu mented, and for the most part the effects that have been found are limited to subtle ones except for specific instances such as in mink and certain bird populations. Based upon laboratory toxicity data and contamination levels found in the environment, one would predict only subtle effects to occur. This is not to say they are not significant. The greatest concern continues to be residues as they affect the organisms carrying that residue-- especially in the eggs and sax products--and as they effect the higher consumers. Apparently water con centrations will have to be kept in the range of .1 to .5 nanogrems par liter if unacceptable residues ere to be avoided. And the evidence to deta is uncon vincing that 1016 is an acceptable substitute as far as aquatic organisms are concerned. SUMMARY OF SESSION V DR, NICHOLAS A. ASHFORD (Massachusetts institute of Technology, Cambridge, Massachusetts): While the effects of PCB's and their possible control ere being pursued it is quite necessary and natural that development of substitutes end their economic and health implications also be examined. In what fol lows, my purpose is to summarize the conference section dealing with economics and substitutes for PCB's. 1 shell present the summary in an order dif ferent from that in which the participants appeared, o as to follow a logical sequence most meaningful to the substitute Issue. Duncan McArthur from the Foster Snell operation presented an analysis of the PCB case which was part of a larger study (called "the Snell Report") of the probable effects of a Toxic Substance Control Act. In the PCB analysis, they addressed the direct and secondary impect of a complete banning of PCB's in the absence of tech nological breakthroughs end new substitutes. They postulated this prohibition would be effected over a period of 76 months, 38 months of which would be consumed with hearings and the promulgation of standards, with 38 months remaining for the tech nological response to eliminate the use of PCB's. The analysis focused on transformer end capacitor manufacturing having e volume capacity of 45 million pounds in 1973. On this basis, they calculate a one-time cost to society of $13.7 million, Sfl.B million of which would effect the secondary users. Thereafter, an annual cost of $110 million per year was anticipated, of which $16.5 million fell upon primary users and $93.3 million on the secondary. There was no detailed examination of tha health and economic benefits to be derived from e banning of PCB's. Dr, Dale Hattis from MIT's Center for Policy Alternatives reported on en examination of both economic end environmental health changes thet may have occurred as a result of the past partial withdrawal of the product from commerce by Mon santo. One of tha factors covered was the increase m fire insurance premiums, estimated as possibly in the tens of millions of dollars and which presumably represented the increased risk as viewed by the in surance industry. It is important to nota that tha methodology was restricted by the availability of information on the nature of substitutes. This points out the complication of trade secrecy end 463 M0NS 205359 proprietary information, which, while presumably being chlorinated, have problems in that regard. legitimate for other reasons, does complicate the Secondly, for capacitors they propose a mixture of assessment of costs and benefits. Two surprises appeared in the study. One had to do with the use of PCB's in paint systems, it was dichlorobiphenyls and their alkylated derivatives, a commercial mixture of which is called chioralky lene. These products are now being examined by an noted that a major group of substitutes evolved which were more economical than the PCB's which they replaced. This evidences a common inertial re sistance to technological change even when it could be anticipated to be more beneficial (in a strictly institute in Bonn for environmental behavior and he indicates that tests already show there is more biodegradation and lower toxicity for these com pounds than for their PCB counterparts, Mr, David Wood from Monsanto Company economic sense) than technology already in use. A described two new products, MCS-1238 and secondary benefit which should result from the de MCS-15BB, for capacitor usage He warns that nei creased use of PCB's is e reduction in the threat to ther is fire resistant although they have much better sport fishing. A calculation of recreational vatua environmental characteristics. Their degradation is could be very large even compared with the alterna more rapid and their accumulation potential in the tive recreational activities which occur as second environment is considerably reduced. Occupational best choices on the part of sport fishermen. The and environmental health considerations indicate a enormous size of the valuation inferred for sport better product with lower acute toxicity. He also fishing makes It easily the largest of the defined announced that they do have candidates with inter costs of unrestrioted PCS disposal. mediate fire resistance between PCB's and mineral A third participant, Richard Rollins, spoke for oil, but did not elaborate on this further. the Electronic Industries Association, which is con Dr. Dean Branson from Dow Chemical Com cerned for the manufacturers and users of capaci pany announced a substitute for use in power capa tors. He cited the Issues of flammability and reliabil citors. This compound is called XPS-4169L and is a ity, and he urged the development of less toxic sub butylated monochlorodiphenyl oxide Once again stitutes. This latter remark was consistent with one we find that e substitute is like the original a chlo very clear message embodied in remarks by the rinated compound. Its properties era worth noting group, namely that his industry was much more concerned with the environmental consequences however. Dielectric iosses are lower or slightly lower than for cepacitor-grade PCB, while the discharge than cost increases in the product. He stated that there are no commercially available substitutes in AC capacitors, including the substitutes presented at this meeting, which are acceptable for safety and reliability. One interesting point made wes that since the components of capacitor-grade PCB (Aroclor 1016) are not what are found in the environ ment, protection of the environment might not profitably be served by attacking the issue of capaci tor use and disposal. It appeared to him that PCB inception voltage is significantly higher. The size or volume per unit of high-voltage power factor correc tion, called kVAR, is about that of the PCB coun terpart, which means that no redesign is necessary for capacitors. There Is little fire and explosion risk indicated by comparing the flashpoints and firepoints of PCB and XFS. The flashpoint for PCB is 166s centigrade, for XFS 174s, The firepoint for PCS is greater than 316s centigrade, while XFS is 199s, This substitute is reported to be more reliable contamination must be coming primarily from some end is anticipated to have a reasonable long-term other industrial source. price. The increased expense is estimated to be less Dr, E, J, Inchaflk for Exxon Chemical reported then S20 for e 200 kVAR unit. The capacity in the on capacitor substitutes based on diisononylphthal- first quarter of 1976 should be in the range of 1 etes with flashpoint of 430s Fahrenheit and which million pounds per year, end a multimillion pound i ere essentially already developed, but not yet fully per year volume capability is estimated by the end proved end tested for health end environmental of 1976. This substitute is more biodegradable by a effects. The Prodelec operation from France presented factor of 45 end the bioconcentration is 30 times less. There is little toxic activity in acute and in an approach which it an incremental modification 90-dey tts, although longer-term tests need to be of previous technology. For transformer use, they carried out. The accumulation in fat is 22 times less recommend keeping trichlorobiphenyl in mixtures The toxicity in fish is on the order of 20 times less with chlorobenzene. Both compounds of course, than for PCB's. 464 HONS 205360 I carried out. The accumulation in fat is 22 times less. The toxicity in fish it on the order of 20 times less then for PCB's. Perhaps the most exciting substitute for use In transformers was announced by Dow-Corning (rep resented by Richerd Montgomery). He indicated thet the globel silicone industry had been looking for a replacement for the transformer fluid PCB's for 5 years, end the technology was now developed for the new fluid. It was to be commercially avail able in 1976 and hed no known environmental problems. Commercial production was available to handle the globel market. In the United States there has been field-testing for 4 years and the product is now ready to be used. The product is called Q2-10 90 dielectric fluid, and is a dimethyl silicone which has been used in the military, in Japen, and in a small experiment in Midland, Michigan, He pointed out that this was not very dissimilar to "dt-gel," which is used of course for human consumption. It is lass flammable than many PCB's with low haat of combustion, high flashpoints and firapoints, and the product is self-extinguishing in case of Ignition by violent transformer breakdown. Insurance compan ies have OK'd the substance for use indoors. The cost Is higher than PCB's but "not outrageous," giv ing rise to an estimated cost increase of about 6 percent in the transformer equipment. Of course, the fluid itself is more expensive, with a higher per centage increase in cost, PC8 transformers now in service can be retrofitted and he believes that the economics are favorable enough to stimulate compe tition. It is worthy to note that unlike the trade industries representing the capacitor users presented at the conference, there was no transformer user or producer represented, it would be interesting to see what General Electric's viewpoint would be on the potential use for this transformer fluid substitute since they have the capability to manufacture sili cone fluids. Their ebsence et the meeting might leave one with an unwarranted optimism for the use of these fluids in transformers. One further reflec tion is that we ere badly in need of a frank assess ment of flammability risk requirements since the substitute products vary in their flammability over the greet range between mineral oil and PCB's. it is not clear what tradeoffs should be made between the fire risks and the safety risks in the industrial setting end the possible damage to humans from substitute products which might get into the envi ronment. It is also not clear that PCB's flammability characteristics should ramain tha benchmark for compliance although the insurance industries may sea this differently. SUMMARY OF SESSION VI MR. CHRISTOPHER M, TIMM (Environmental Protec tion Agency, Region V, Chicago, Illinois): From a very broad mixture of topics and points of views thet we were listening to last night, I believe tha following four points should be emphasized. First, on top of all the human health and wild life effects that have bean documented and thor oughly discussed, PCB's are having a definite end drastic affect on the livelihood and future of tha freshwater fishery and fishermen. This is a very real problem to the people In various perts of tha conti nent and they see no improvement in the near future. Second, a ban on PCB's and better control of other toxic substances to protect our natural re sources is long overdue. However, tha actions of tha regulatory agencies such a* EPA and FDA must be based on scientific fact in the overall impact on tha nation. Third, universally there is a belief that the governmental bodies and agencies for whatever reason are far, far too slow in solving environmental problems like PCB's. This is a frustration to every body. And finally, there is a need to find some way to compensate the people like fishermen whose liveli hood is impected by environmental pollution which ts PCB's. They do not cause the problem, they can not control tha problem, and they often cannot find anyone to blame or even talk to about it. But they suffer tha consequences of decades of Incomplete evaluations and tasting of new compounds. Thank you. 465 HONS 205361 A3U m SUMMARY OF SESSION Vl'J MR. CHARLES N. GREGG, JR. (Environmental Protec tion Agency, Washington, D.C.). Because most of flow of PCB's first from Industrial situations into the environment and thereafter within the environ you have heard the discussion this morning, I will ment to locations where they can teed to higher try not to repeat it, but to provide some insights human and environmental exposures. In my view, a and perhaps some of the highlights. I will not try to voluntary program seems to present a very great op give equal time to the various speakers. portunity for improvement, perhaps much greater First, there is en obvious distinction between than a strictly regulatory program in the light of physical and technical methods of control, which some of the difficulties experienced in using our have been discussed in other sessions, and the regu current authorities. latory and voluntary actions for achieving those Relatively less. It seemed to me, was said by controls that were discussed by this morning's pan this morning's speakers about just how to control el. PCB's, particularly how to control, through regula Second, there is a distinction between the di tion, those PCB's which are currently in industrial rect control of human exposures as, for instance, use or elsewhere in products but not yet released through limitations on PCB's In fish that can be sold generally to the environment. There was some refer for human consumption, and limitations on use or ence to controls over disposal, but to my best recol limitations on emissions into the environment, lection, there was no indication that we had any which In the long run contribute to diminished ex- directly applicable authorities with respect to dis posura. In our present situation, as you were told by posal. the speakers this morning, there ara a vast number Let me touch on a couple of this morning's of Federal agencies with roles. Our Government and highlights. Or. Ahmed of the NR DC asserted that the Canadian Government both contribute to solu the government had failed to carry out its responsi tions of the Great Lakes problem. We have a lot of bilities adequately, particularly under Section State Governments with roles to play. One of the " 307(a) of the Federal Water Pollution Control Act. major problems will be sorting out rotes, and finding He fait that we had a schedule on which we should adequate cooperation in performing those roles, have produced regulations a couple of years ago, among the several agencies and units conoernad. with compliance a year ago, and he criticized EPA's A further complication is that both in Canada lack of attention and priority to toxics in our Water and here we not only have a number of regulatory Pollution Control program. He msde several recom authorities now, but in each case we are looking for mendations: a phaseout of the manufacture and use additional authority which it is anticipated will per of PCB's, a ban on axports and imports, devalop- mit much mora finely applied solutions. And at the mant of an Inventory of point sources, additional same time that we plan for the future, we do not monitoring in fish and alsewhere, a moratorium on know for certain what authority we will have availa river bottom dredging until wa have better indica ble for use. tions of the trouble we stir up, affluent standards One observation I made was that there seemed that would allow us to arrive at 1 ppt in water, to be vary little real optimism, tf we applied all our lower FDA tolerance levels, and the passage of the available resources and used ail of our authorities as Toxic Substances Control Act. best we could, .we could solve in any short time Mr. Wessel of the Food and Drug Administra frame the most pressing problem, which appears to tion referred to Its action in 1972 and 1973 to set be the high levels In fish In a number of places tolerance levels, indicating that various concerns had where they ara caught and consumed in substantial to be balanced in setting levels under Section 406 of i quantity. This lack of optimism did not, neverthe tha Food, Drug, and Cosmetic Act. He indicated less, suggest to the speakers that we should not take that FDA was examining the current tolerance level action. Everybody seemed to agree that It was ap in fish and considering whathar or not to lower It. propriate to move ahead as best one could with the Ha said that thare would be adequate opportunity full range of authorities and voluntary programs for public comment on any proposal that was made. available. - But he felt that this would not solve the PCB prob Also, there was considerable emphasis on non- lem and it would not necassanly pravant consump regulatory action, and incraasing communication tion of fish with high levels of PCB's by private with people who have the opportunity to affect the fisherman. * 466 HONS 205362 Dr. Kolbye of FDA added a discussion of some of tha problami fn setting tolerance levels, and something else I thought was significant: that steps are particularly needed to identify where PCB's are located so we can look to thair proper disposal, and education to this and is needad, Ha did feel that tha average consumer is fairly well protected against PCB's by the current tolerance level, but acknowl edged that there would be higher exposures in some cases and that this was not a concern to pass over lightly, Mr. Barber of tha Environmental Protection Agency, after talking about soma of our authorities and programs wa have undertaken so far, gave con siderable attention to some of tha realities Involved in EPA decisionmaking: tha complexity and impli cations of taking various ra^latory courses, and tha fact that there are limited resources in EPA, particu larly people, to handle a wide array of regulatory responsibilities. Ha pointed out tha importance of tha State role, and Indicated that tha Federal Gov ernment's role can best be viewed as one way of encouraging tha State to find ways to perform a great deal of tha regulatory and enforcement activi ty. Ha fait that regulation must represent some sort of consensus and be anforceebla In order to be pro ductive, He felt that a number of PCB problems were difficult to control because of the numbers of nonpoint sources. He urged that we try tor more awareness among the people who use PCB's, particularly the utilities, and suggested voluntary labeling and use of the planning process under Section 208 of the Federal Water Pollution Control Act. Secretary Read described both the environmen tal problem caused by PCB pollution and tha result ing fisheries resource problem. High investmant in restoring the Great Lakes fishery and future invest ment In this and other fisheries would be hard to justify unless we can control the PCB situation. He suggested particularly that since we find great reduc tions in DDT and mercury as a result of regulation, it would certainly be worth a try to see if we can reduce PCB levels in the water and in fish by taking all of the regulatory steps we now can. He endorsed the Toxic Substances Control Act, and suggested we cut off the importation of PCB's. Dr, Rhoden outlined the plans of NIOSH. Mr. Billy of the Marine Fisheries Service indi cated their environmental, consumer, and public information concerns. They recommend not lower ing the FDA leva! until there has been a sound at tempt to understand the course to be followed, and the avoidance of unproductive and unnecessary ad verse publicity, Mr. Grella of DOT briefly described their incipi ent program to apply DOT authorities to PCB's, though not much has yet bean done. The Coast Guard has a number of functions under the Federal Water Pollution Control Act in tha event of. spills, but the Coast Guard representa tive told us thet until wa in EPA have designated PCB's as a hazardous substance, the Coast Guard is unable to go forward to use its authorities. Ha urged public awareness of the needs for good handling and precautions in transportation. Dr. Milison of the Canadian Govarnment urged a systematic approach, and outlined six regulatory control packages that Canada was considering. He emphasized that Canada does not have a use control act yet, but that such authority togethar with their other authorities would permit them over some peri od of time to do a great deal about controlling PCB's. Since Dr. Highland spoka last, and I heve exhausted my time, with apologies to him I hope you remember what ha said. HONS 205363 467 CONFERENCE HIGHLIGHTS Richard A. Carpenter* A summary of this complax and comprehensive con ference may be more useful if the information Is orga nized in the format shown In the accompanying figura (figure 1). The presentations have dealt with three gen eral topics: A, The occurrence of PCB's in the environmentsources, rates, routes, and sinks; B, The toxicity of PCB's--inadvertent human exposure, laboratory animal experiments, wild life, fish, and ecosystems; C, The uses and benefits of PCB's to industrial society and the possibilities of control. In each topic, information can be characterized as 1. What is known and generally agreed upon with a reasonable degree of confidence. 2. Remaining uncertainties and tha reasons why a lack of understanding continuas. Science is probabilistic in nature and this concept of uncertainty must be recognized whan technical information is used in deciding issues of public policy. 3. Finetly, tha conferenca discussions have sug gested some courses of action which ara pru- A. Occurrence in the Environment 1. What Is known B, Toxicology C. Uses, Benefits and Control 2. Remaining Uncertainties . 3. Prudent Actions Figure 1. Organization of information about polychlorinated biphenyls. * Executive Director, Commiition on Natural Reiourcee, National Research Council, Wellington, D.C. 468 HONS 205364 asszssss aqnil'JHHW m !! iitwni ntfrqapdew. Vi.* Y i j dent, i.a., could and should be set in motion. These Include setting priorities for obtaining mora information and reducing uncertainties through additional research and monitoring. Tha conference was not designed to produce con sensus judgments nr to make recommendations. Thus, the following summary mutt be viewed as the responsi bility of the author alona. A-1 What it known about tha occurrence of PCB't in the environment We hava learnad what should have been apparent from the start--that any persistant, mobile, and foreign or exotic compound is going to be detected everywhere in the environment. In addition to current production and uses, which may result In leaks, a nonpoint source situation exists in that about 400 million pounds of PCB's ere already discarded in the environment and sub stantial amounts are apparently recirculating in sludge, sediments, In eir and dust, and in contaminated orga nisms. Thare are about 300 million pounds in industrial service end this material will be difficult to contain com pletely as It moves toward disposal. The sediments in lakes, rivers, and estuaries provide a vary large reservoir of PCB's for contacting aquatic organisms. The material in dumps (three-fourths of the total discarded) appears to stay there for the most part. Currant processing lossas are Important and can be decreased. Eventual removal is to sediments in the deep ocean and we need to know more about tha fata of this mala rial in tha marina environment. it Is too early to see tha affects of the 1972 volun tary action to limit uses to nondisperslve applications, but certainly It was a justified decision and a move in tha right direction. Thera will be occasional catastrophic spills which can causa substantial damage to fisheries In the future. These will be localized impacts, and will be costly to clean up. Incineration is an affective method of destroying PCB's If the temperature it high enough (i.a., about 2.700 F), Analytical procedural now give confidence that we can measure PCB's qualitatively and quantitatively down to a few parts par trillion. A-2. Uncertainties about PCB't in the environment Thera is a real question as to whether the PCB con tent of tha waters of the Graat Lakes (particularly Lake Michigan) can be lowared by any dagra. of tightanmg-up of tha currant use situation, because of tha recirculating contamination that Is already there. There Is the quas- tion as to the role of air transport and the recirculation of material that is deposited in rain or in dust back Into the air so that it is continually redistributed around tha world. The composition change of PCB's in the environ ment with aging is not well understood; there era ques tions as to their chlorine content changing and regarding formation of diobenzofurans, Wa need a mass baianca and a modal for transport and removal in order to estimate the time thet will be required for these matarials to eventually move to an ultimata sink in tha daap ocean sediments A question has been reised as to the possible conver sion of these matarials into higher chlorinated com pounds during sewage chlorination. Wa need to know mdre about tha presence of tha materials in whole watar; i.e., are we measuring material on suspended sediments, in vary small organisms, in micelles, or actually dissolved in water? Wa need to know about tha biological activity of these various forms of occurrence of PCB's In watar. A-3. Prudent actiont What can we do based on this information and' uncertainty? We cen separate, to some extant, the prob lem of whet is alreedy in the environment from tha con trol of material that has not yet been released. Even If all manufacture and use were stopped immediately, envi ronmental contamination would remain for some time to come, Tha PCB problem should be considered in the context of other halogenated hydrocarbons in tha envi ronment and it should not be separated from Investiga tion and control of tha residues of pesticides and other halogenated materials. Work should begin on a more systematic monitoring system and on tha use of indica tor organisms, such as the suggested "mussel watch," on a worldwide bests. We can usa some ingenuity in devising means of cleaning up contamlnatad water. This problem Is of a magnitude that allows one to think about filtration or adsorption concepts for waters that ara somewhat con fined. Ingenuity may suggest ways to make contaminated fish suitable for use In animal feeds or human contump' tion. Perhaps segregation of certain organs or particular methods of cooking would serva this purpose, or soma other way of decontaminating these valuable animals might be found. B-1 Whet it kno wn about toxicity The Yusho Incident proved the toxicity of used heat transfer fluid to humans at a concentration in cooking oil of about 1,000 ppm of PCB's. But Interpretation of this Incident Is confounded by dibenzofuran contamina 469 HONS 205365 A tion of th* PCB fluid, industrial hygiene experience [I somewhat reassuring as to toxicity to humam except that the occasional symptom* and illnesses cannot be related to known exposure dose* in most instance* The good housekeeping practiced by some large users and the American manufacturer wiii probably be better than that of the variety of secondary users. No human deaths have been caused directly, but reports of serious illness and persistent skin problems conttnue. Exposure of the general public can be controlled by avoiding food (mainly fish) contaminated with PCB's. Exposure from environmental contamination or direct .introduction into humans is unlikely. Averages for die tary intake can be misleading since some persons mey eat large quantities of fish. Laboratory animals show effects when fed diets containing contamination levels found in fish. Fish are effected at the range of PCB levels found neer Industrial outfalls into ambient waters, and the occurrence of fin rot In fish naar these "hot spots" is e direct confirmation of laboratory tests as to the effects on fish. Ecosystem simplification (fewer species end lower populations) has been found in laboratory experiments to occur at concentrations similar to those in hot spots In nature! ambient waters end could be expected to be found et sludge dispose! sites. It is hard to find evidence of damage to terrestrial ecosystems. Biomegnification, i e,, the ratio of the PCB content in aquatic organisms to that of the water in which they live, can be as high as several hundred thousand, 8-2. Uncertainties as to toxicity There is confusion over the interpretation by patho logists of organ damage, it would be helpful if the highly technical problem* of ascertaining carcinogenicity could be worked out by those scientists involved apart from the complexity end emotionalism of e specific issue such ei the PCB problem. The effect of dibenzofurens, which may be present es impurities or as metabolites, is still In question. There is e greet variation es to the response of dif ferent species in laboratory animal tests. The range of sensitivity Is large. More needs to be known as to wheth er the reproduction problem Is the most important ef fect. Fet metabolism is not wail understood and since e greet proportion- of the human population is carrying around a few ppm of this materiel, we need to know more about it Wildlife toxicity data is poor and we need to know which wildlife species may react es do chickens and mink. The relationship of toxicity to chlorine content of the PCB's is uncertain, is the ability to metabolize these compounds (which varies with the chlorine content) desirable or not? The possibility of dioxin as a degrada tion product has been raised. We need to know about the equilibrium distribution of these materials between fish and water, is it possible that depuration can be a help? Are PCB's further accumulated up the food chain after the biomagntfication from water to the first orga nism? B-3 Prudent actions based on toxicity knowledge Certainly more experimental work in animals and careful replication of reported tests are necessary. Prior ity should be given to chronic tests in various species, detection of behavior ch*nge in animals, and laboratory work at true environmental levels, rather than to greatly increased levels of dose. Obviously it is of great impor tance to determine unequivically whether the PCB mate rials are carcinogenic. We need to coordinate this work with experiments and observation* on other halogenated hydrocarbons, particularly the chlorinated hydrocarbons, and to look at combined effects on organisms, communities, and ecosystems. NIOSH should extract the maximum from industrial hygiene date because these human exposures do not necessitate the inferences from animal tests to human toxicology. The widespread occurrence of PCB's in the environ ment constitutes en inedvertent experiment on human populations end the biosphere. A concerted effort at monitoring and analysis is indicated in order to gain the most useful knowledge for further decisions concerning toxic substences et low levels m the environment. C-i. What is known about uses, benefits, and control problems We know that about 700 million pounds of PCB's have been manufactured, but the current annuel produc tion volume is down to 40 million pounds from an 80 million pound level In 1870. About one quarter of pres ent production is going into small capacitors that are scattered very widely throughout our industrial society. The fire retardent benefits of PCB's ere real and important. An abrupt change in the availability of PCB's would be disrupting, but that is unlikely in any event. The estimate of 76 months to reach an end to manufac ture if the Toxic Substances Act existed today suggests that industry will heve a substantial transition period. Forty-five years of use has imbedded PCB's m US industrial practice and it will be costiy to replace these unique materials. Alternative dielectric fluids are on the way, but wiii not be suitable as replacements in axisting transformers. 470 MQNS 205366 C-2. Remaining uncertainties The decision by Japen apparently to move further to eliminate these compounds is a real challenge in the public mind to the regulatory policy of the United States if that Nation can do without PCB's. why cannot we? Is a total ban worldwide necessary in order to re duce and eliminate contamination to the North Ameri can environment? An inventory of PCB's in existence is required and this must be international We need to know more about the changes in PCB's in use, i.e.. dibenzofuran formation. How nondispersive are "clos ed" electric systems? We need to reconcile the differences in human food tolerance limits as established by the United States (5 ppm) and Canada (2 ppm) and In alternative proposals from various protagonists on all sides of that question. Cost/benefit analysis will not be very helpful in the PCB contamination problem because of the great num ber of subjective judgments and different value systems Involved In ernving et a balance. In any event, the margi nal costs end the marginal benefits ere what must be determined. We need to know how to remove PCB's from waste water, i.e., what would be best practicable technology economically achievable In order to get to an effluent standard, and whether that should be 5 ppb, or zero, or whet level. We need to know whether 1 ppt is a reason able ambient water standard in view of the large biomagnificanon factor C 3, Prudent actions EPA has a responsibility to determine priorities and it needs to review the PCB issue in terms of the total set of pollution probiams end the agency's resources. EPA should proceed with effluent standard possibilities in Section 307 of the Water Quaiity Act (PL 92-500), although such action may end up in court tests. The Endangered Species Act may be a means of cooperative action by other Federal agencies. Voluntary housekeeping by industry can be in creased to a substantial extent, but this requires special attention to the weakest firms, always a problem with voluntary cooperation. Payment of compensation to fishermen mBy require an act of Congress similar to the experience with heptachlor in milk some years ago It is my personal opinion that the inadvertent and unavoidable addition of PCB materials to foods could be covered by the Delaney Clause if they are found to be carcinogenic in appropriate animal tests. This conference has addressed a real problem and was not just a demonstration of the prowess of analyti cal chemistry. However, as with any environmental man agement issue, the PCB problem must be put in perspec tive. PCB's will be in the environment for a long time Fisheries resources in some of the Great Lakes and rivers have been lost. We can protect against any imminent hazard to human health. Ecosystems are resilient but local damage has occurred. Further leaks from the Industrie! system must be prevented. Internalizing costs will lead the market to produce replacements for PCB-'s Human health is most important but environmental quality is a reflection of the ecosystem that we all share. In this case there may be a coincidence, m that if we protect human health adequately, we will have protected the environment. All elements of society are in this together and recriminations are not very helpful. Scientists and engi neers can generate and deliver information for rational enforcement decisions, searching for equity as the inevit able tradeoffs are made. Verified technical facts and their implications must be communicated efficiently to the public through education and information programs Most importantly, we must use our ingenuity in solving ,, little parts of the problem when they are all that can be solved at well as in working on an ultimate solution for the problem as e whole. 471 MONS 20536? technical report data (Pleett read /ntlructions on the reverte before completing) i REPORT NO. 2. EPA-560/6-75-004 4 TITLE AND SU0TITLE National Conference on Polychlorinated Biphenyls (November 19-21, 1975, Chicago, Illinois) 3, RECIPIENT'S ACCESSION NO. S REPORT OATE March 1976 6 PERFORMING ORGANIZATION CODE t author(S) Franklin A. Ayer (Compiler) 9 PERFORMING ORGANIZATION NAME AND AOORESS Center for Technology Applications Research Triangle Institute P.0. Box 12194 Research Triangle Park, North Carolina .12 SPONSORING AGENCY NAME ANO AOORESS 27709 Office of Toxic Substances Environmental Protection Agency Washington, D.C. 20460 1S. SUPPLEMENTARY NOTES EPA Project Officer - Thomas Kopp a performing organization report no 10, PROGRAM ELEMENT NO. it, conTract/grant no. " 68-01-2928 13. TYPE OF REPORT ANO PERlOO COVEREO Proceedings Nov, 14, SPONSORING AGENCY COOE - The objectives of the conference vhere to bring together the latest data and best available expertise to help clarify the problems associated with the manufacture, use and disposal of PCBs ... help assess the effectiveness of steps taken to reduce the problems associated with PCBs .,. provide a platform for interested parties to present previous neglected data concerning PCBs ... help clarify the feasibility and ocnplicatians of steps to reduce the problems associated with PCBs. t * 1 IT, KEY WORD* AND DOCUMENT ANALYSIS OMCRIPTORS b.lOENTIFIERS/OPEN ENOEO TERMS c. COSAT I Field/Gioup Polychlorinated Biphenyls (PCBs) . PCS Health Effects 1 PCB Human Exposure PCB Uses, Soirees, Identification PQJ Environmental Fate PCB Occurrence 55 geological Effects & Exposure * rnTFaiVui 1 ON statement"3*c --------------------------------- 19 SECURITY CLASS (Thit Report) 3t NO OP PACES f _4&Z L 20 SECURITY CLASS (Thttpage) 22 PRICE MONS 205368 4 UNITED STATES ENVIRONMENTAL PROTECTION AGENCY Office of Tonic Subttinc*! Wtihlntton, D. C. 30460 OFFICIAL BUSINESS AN EOUAL OPPORTUNITY EMPLOYER WH--667 POSTAGE AND FEES PAIO u.s. environmental protection AGENCY EPA-335 Return tMs theet if you do NOT with to receive this metwieU I, or If change of eddres* is needed! I. (Indicste change. Including ZIP code) Mr. W. Wayne Withers MONS 205369