Document 7M8B5Y6onbErME1XD4o2VgZZo

21 November 1975 Session Vili: SUMMARY SESSION John L. Buckley, Ph.D. Session Chairman 467 MONS 070113 SUMMARY OF SESSION I DR. J. G. VOS (Rijks imtituut voor de Volksgezond- heid. Bilthoven, The Netherlands): Recent findings on the biological action of PCB's, such as carcino genicity m rodents and the disturbed reproduction in monkeys, greatly increase our concern of PCB's as a health hazard. . In summarizing the papers presented in the session on health effects, one is confronted already in Dr. Kuratsune's paper with the problem of PCB's and chlorinated dibenzofurin impurities. In the "Yusho" disease, one is struck by the persistence of symptoms present in patients, although there is a shift in the pattern, a decrease over the years jn the skin lesions but a persistence of hypersecretion of Meibomian glands. In "Yusho" patients, increased urinary excretion of 17-fcetosteriods was noted, as was an increase in serum triglyceride levels. Changes m the menstrual cycle were observed in a high per centage of female patients. Mean blood levels in "Yusho" patients were 7 ppb. This level conflicts with the high PCS concentrations 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 dibenzofurans (including 2.3,7,8-TCDF) in rice oil. Apparently furans were formed in the PCB during its use as a heat exchang er, since the level of chlorinated dibenzofuran in Kanechlor KC-400 was approximately 17 ppm. Of particular significance was the relatively high con centration of chlorinated dibenzofurans versus PCS' s in the liver of some patients who died, when compared with adipose tissue values. Further studies ere required to solve the dilemma of the importance o* furens in the etiology of "Yusho" disease; and in e wider context, to get information on pouible changes in composition or concentrations of chlo rinated dibenzofuran and other contaminants in used PCS'* and on their fate in the environment. During the 1971 PCB conference, there was *me concern on a bladder tumor that was found in * ret by Or. Kimbrough. Now we know that this tumor apparently developed spontaneously. But as ** flB4fd from Dr. Kimbrough, in recent studies cer^In PCB mixture* induce tumors in rats and mice, spectrum of lesions are induced in livers of rats 100 ppm Aroclor 1260 for 21 months: hyper- P**tic or neoplastic nodules in 80 percent of the an,mals and in none of the controls, and D^tocelluiar carcinomas in 14 percent of the ex- perimental animals and in one out of 173 controls. Metastases were not observed. However, hepato cellular carcinomas were not found in the chronic study m 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. When Rhesus monkeys were fed 2.5 or 5 ppm Aro clor 1240--that is, approximately 0.1 or 0.2 mg/kg body weight/day-skin lesions consisting of acne of face and neck, edema, and hair loss developed in some 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 in 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 infants born were small. Fifty per cent of them died before weaning, showing typical lesions. These effects on reproduction may ba due to an estrogen/progesterone imbalance. Female rhasus monkeys on a PCB diet had increased urinary levels of ketosteriods. By comparing the reports of Drs. Kuratsune and Allen, one is struck by the similarity of lesions present in "Yusho" patients and those produced ex perimentally 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 the 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 tow chlorina ted isomers. After 6 weeks, 85 percent of the 2,4,5,2',4',5'-tsomer was still present in adipose tissue and skin, while the residue of 2,4,5.2',5'-isomer 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 A HONS 070U'* rut facilitate the formation of arene oxide inter-, mediates, as was also reported by Or. Allen in his study with the 2,5,2'5 -isomers in the monkey. Dr. 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 P'obebly due to their higher persistence. For enjymes less discretely localized m the liver cell, such et carbox y lestei ase and sulfobromuphthalein -ilutathion conjugating enzyme, the position of chlorine atoms appears of less importance. Purified lisubstituted biphenyl did produce enzyme induc tion. though enhanced effects were noted when one 0 more chlorine atoms were present. As can be concluded from the report of Dr. t cca. biological effects cf symmetrical hexachlo1 'i'ifenyl isomers differ not only quantitatively but .so qualitatively. Such comparative studies are niressary for the ultimate goal--that is. the under standing of the biological effects produced by com plex mixtures that endanger human health, mixtures Udl are different from those formulated commer cially. Of the three isomers tested in mice, 3.4,5.3', 4.5'-HCB was most toxic, followed by 2,4,6,2',4',6 'HOB and 2.4.5,2',4',5'-HCB, respectively. Liver weights were increased by all three isomers. Severe trymus atrophy and a decrease in a- and y-globulins wive produced only by 3,4,5,3\4',5'HCB. In a si jdy in chickens, these isomers along with 2,3,4,2 \.i'.4'-HCB and 2,3,6,2',3',6'-HCB were given at 400 ppm m the diet for 3 weeks. Again, 3,4,5.3'.4' ,!)' HC8 was most toxic and was lethal even at 3 ppm. Chickens exhibited pronounced edema, thy mic involution, and marked liver pathology. How ever, chickens that were fed 100 ppm died earlier ar.n had only mild liver pathology. The 2,4,6,2',4' ,h-HCB was less toxic (no deaths at 400 ppm) but caused marked liver pathology and highest liver weight increase. The toxicological effects of 3.4,5,3',4\5'*HCB differ qualitatively from the oiher HCB isomers studied, and resemble the lesions produced by 2,3,7,8-TCDF. Dr. McKinney reported on metabolism studies ol HCB isomers in the chicken using low resolution mass spectrometry. When metabolites were detecte-\ 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'-HC8. Metthydroxylation followed by parahydroxyiation of the same ring are favored processes for 2,4,5,2',4', 5'-HCB. Further oxidation could give quinone. The presence of a metabolite with a trihydroxypentachlorobiphenyl structure indicated that dechlorina tion cjo be concomitant with hydroxylation. A diben/uki'an metabolite was not detected. I' the case of 2,4,6,2',4\6'-HCB, several re act'" types occurred: dechlorination, Isomerizai o^ and dibenzofuran formation. This isomer had lowest effect on body weight, did not give a high : v- residue, but produced most severe liver path '!v despite the dibenzofuran formation. In cono.: 3,4,5.3',4',5'-HCB accumulated most in liver ! fat, was most toxic with "furan"-type ef fect r* m metabolites were not detected in the ex creta However, one has to consider in the case of 2,4.6 2 ,4',6' HCB and poaibly 3,4,5.3',4',5' HCB thj 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 tha 2,4,6,2',4',6'-isomer, 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 the first toxicity studies with 2,3,7,8-TCDF. Marked thymus atrophy and the presence of edema are seen in chickens dosed daily with 1 pg/kg. Only mild liver pathology was present at the 5-pg dose level, which produced TOO percent mortality. The LDS0 in guinea pigs after a single oral dose was approximately 7 pg/kg body weight. In chicken and guinea pigs, 2,3,7,8-TCDF is lethal at dose levels that are less than one order of magnitude higher than that of 2,3,7,8-TCDD and share a number of biological effects. Mice 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 mice. 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. 460 *GNS 070^15 SUMMARY OF SESSION II MR. DAVID GARRETT (Environmental Protection. Agency,- Washington, D.C.): In Session II, Of. jimn Mieure, who it research group leader, Mon- unto Induitrial Chemicals of St. Louis, spoke of PCB's, their properties and mixtures, and presented physical and chemical properties of commercial Ard* dor product*. .* Dr. Stephen Safe, Associate and Professor, De partment of Chemistry, University of Guelph. Ontario, presantad an overview ofAnalytical identif ication and spactroscopic^ropertifes. Key among the points stressed were thetSophiiticated methods end;* equipment are available &r identification and quary tificstion of PCB't at extremely low level*. Dr. Robert Durfee, Vice President of Verier, Inc., presented topical infprmation on the manufac ture and utes of Aroclors in the United States and alio gave 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 caning process it self was reviewed. Thomas E. Kopp of the Office of Toxic Sub stances in the Environmental Protection Agency re viewed past, present, and possible future regulatory activities of EPA concerning PCB't in the water environment. He discussed proposed voluntary stan dards bring prepared by NEMA, ANSI concerning labeling and safeguards for handling askarels and aikarel-containing equipment. Then, Mr. Stanton Kleinert, who is Chief of Surveillance for the Wisconsin Department of Natu ral Resources, discussed sources of PCB't in the State of Wisconsin, emphasizing the probable role of intermedia transfer from air to water and deacribing some possible sources of contamination for food and water. And lastly in this stetion, Mr. John Hesse, Supervisor of the Toxic Materiel Unit, Department of Natural Resources in Michigan, described uses of PCB's and losses to the environment of Michigan. Mr. Hesse also emphasized PCB losses to air and the probably significant transfer of these PCB's into the water medium. Data was presented on PCB concen tre tions in municipal treatment effluents end 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 greeter 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 and 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 the environment and its in habitants, the task of cleanup is monumental, even if vwt had proven technology with which to accom plish this task. Thank you. SUMMARY OF SESSION III R- IAN C. T. NIS8CT: Eleven major points came out in the course of our session on transport and accu mulation of PCB's in the environment. 1 Wa know almost nothing about chlorinated dibanzofurens, except that they are present in Aroelor 1242 and 12B4, and we learned during Session I that they are formed in use end they ere formed by '"taboliem. 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, othrfr releases continue. These in clude releases from manufacturing, leaks from sup posedly dosed systems, scrapping of PCB's manu factured before 1971 and of materials containing them, end use in nonciosed systems of material that 461 NQNS 07G116 it either imported or diverted from other uses. 3. Surprisingly large quantities of PCB's which match Arocior t254 or 1260 are still being found in air and ;n dry fallout and precipitation. It is difficult to account for these quantities in terms of known past uses, end accordingly may have to look for a significant current source of air emissions. Perhaps this may be air emissions from transformers, or dis* posai of scrap materials from them. . 4. There is circumstantial evidence that PCB's that ar now trapped in targe quantities in sediments in lakes, rivers, and estuaries will remain available for resuspension and wilt oontinua Jo move slowly downstream. We do not^have any precise infor mation about their persistence or about the time it . will taka them to move downstream into the sea/ but we believe that it is to be measured in years, if not decades. 5. Although PCB levels have decreased consider ably in some components of the environment such as terrestrial birds or the mussels collected off California, as yet there is no clear indication of a consistent decline in PCB residues in fish. Wa should not expect rapid decline, because of the long re tention time of PC8's in the environment and in human tissue. 6. In addition, many itams containing PCB's have service lives of 10 to 20 years before they are dis carded, to that we are still experiencing releases of materials manufactured before 1971. 7. Because of time lags in response we may not yet have reached peak levels in some compartments in the environment. I am thinking hart particularly of estuaries, where levels of PCB't may continue to increase as sedimants are transported downstream. 8. Most human exposure to PCB's in the diet is via fish, although there is some human exposure via other routes, such as milk, meat, and by inhalation in the air. The information from the FDA total diet program suggested that the dietary exposure of an average adult in the United States is of the order of 10 micrograms per day. However, an average for PCB's has tittle meaning because of the very wide variations in individual consumption of fish and enormous variations in the contamination levels. 9. Individuals who h*re a dietary preference for freshwater fish will teke in much more than the average--in some cases at least a hundred times as much as the averaga. Breast-fed infants appear to have extremely high dietary intakes of PCB's, aver aging about 50 times higher than that of their mothers on a milligram per kilogram basis. The breast-fed infant appears to be one of Dr. Kolbye's special consumers who is imprudent enough to eat the same diet every day. 10. Monitoring of PCB residues in human fat in the United States and Canada shows that the median PCB concentration is of the order of 1 ppm. Again there are enormous variations, at laast a hundred fold variation between the highest level recorded and lowest level detectable. 11. Finally, although tetrachlorobiphenyls are more eesily degraded in the environment thin pentachioro- or higher chlorinated compounds, the tetra chlorobiphenyls ere nevertheless accumulated and retained by fish. Accordingly there are significant human intakes of tetrachlorobiphenyls, even though they are not retained in significant quantities in human tissues. Therefore, release of either Arocior 1016 or 1242 into aquatic systems will lead to some human exposure to tetrachlorobiphenyls. SUMMARY OF SESSION IV OR. DONALD I. MOUNT (Environmental Protection Agency, Duluth, Minnesota): Among and between the birds, memmeis, end aquatic organisms there are marked differences in sensitivity to PCB's. Even so, these differences are not large when compered to species differences found for other pollutants. Likewist. there are differences in the toxicity of various Aroclors and isomers of PCB's that are real but not large. While increasing chlorine content increases tox icity in warm-blooded animals, increasing chlorine content decreases toxicity of PC8'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-life and bioconcentration in ail ani mal groups, but the evidence is not entirely dear cut on this point. To generalize, we can say that in most case* acute lethal toxicity in birds and mammals occurs 462 M0NS 070117 9 from 10 to 100 ppm in the food, while mote sensi tive species may suffer death from 1 to 10 ppm in the food. Concentrations of about 5 ppm in bird eggs produced death. And concentrations of l*C8'$ from .5 to 5 ppm in food produced reproductive or growth effects. For aquatic animals, water concen trations of 10 to 100 micrograms per liter are acute ly lethal. Concentrations of 1 to 10 microgramt per liter produced chronic reproductive or growth ef fects end water concentrations of 1 to 10 nano grams per liter (ppt) producedyesidues of biological or public health significance. * Direct uptake fdom water into aquatic orga nisms is vary significant and appears to produce con centration factors ort the order of one hundred thousand or more times. Water uptake supplement ed by food intake results in 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 and for various mixtures and iso mers of PCB's. Enzyme systems of poikilothtrms 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 pan the effects that have been found are limited to subtle ones except for specific instances such as in mink and cartain bird populations. Based upon laboratory toxicity data and contamination levels found in the environment, one would predict only subtle effects to occur. This <s not to say they are not significant. The greatest concern continues to be residues as they affect the organisms carrying that residue-- specially in the eggs and sex products-end as they effect the higher consumers. Apparently water con centrations will have to be kept m the range of .1 to 5 nanograms per liter if unacceptable residues are io be avoided. And the evidence to date is uncon vincing that 1016 is an acceptable substitute e> 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 are being pursued it is Quite necessary and natural that development of substitutes and 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. I shall present the summary in an order dif ferent from that in which the participants appeared, $0 as to follow a logical saquenca 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 impact of a complete banning of PCB's in the absence of tech nological breakthroughs and new substitutes. They Postulated this prohibition would be effected over e Period of 76 months, 38 months of which would be consumed with hearings end 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 and capacitor manufacturing having a volume capacity of 45 million pounds in 1973. On this basis, they calculate a one-time cost to society of $13.7 million, $8.8 million of which would affect the secondary users. Thereafter, an annual cost of $110 million per yeer was anticipated, of which $16.5 million fell upon primary users and $93.3 million on the secondary. There was no detailed examination of the health and economic benefits to be derived from a banning of PCB's. Dr. Dale Hattis from MIT's Center for Policy Alternatives reported on an examination of both economic and environmental health changes that may have occurred as a result of the past partial withdrawal of the product from commerce by Mon santo. One of the factors covered was the increase in 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 note that the methodology was restricted by the availability of information on the nature of substitutes. This points out the complication of trade secrecy and MQNS 070118 proprietary information, which, while presumably legitimate for other reasons, does complicate the assessment of costs and benefits. Two surprises appeared in the study. One hadto do with the use of PCB's in paint systems. It was noted that a major group of substitutes evolved which war* 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 fin a strictly economic tense) than technology already in use. A secondary benefit which should result from the de creased use of PCB's is a reduction in the threat to sport fishing, A calculation of recreational value could be very large even compared with the alterna tive recreational activities which occur as second bast choices on the part of sport fishermen. The enormous size of the valuation inferred for sport fishing makes it easily the largest of the defined costs of unrestricted PC8 disposal. A third participant, Richard Rollins, spoke for the Electronic Industries Association, which is con cerned for the manufacturers and users of capaci tors. He cited the issues of flammability and reliabil ity, and he urged the development of less toxic sub stitutes. This latter remark was consistent with one very clear message embodied in remarks by the group, namely that his industry was much more concerned with the environmental consequences than cost increases in the product. He stated that there are no commercially available substitutes in AC capacitors, including the substitutes presented at this matting, which are acceptable for safety and reliability. One interesting point made was that since the components of capacitor-grade PCB |Aroclor 10t6) are not what are found in the environ ment, protection of the environment might not profitably bt served by attacking the issue of capaci tor use and disposal. It appeared to him that PC8 contamination must ba coming primarily from some other industrial source. Or. E. J. Inchalik for Exxon Chemical reported on capacitor substitutes based on diisononylphtbal- atas with a flashpoint of 430 Fahrenheit and which are essentially already developed, but not yet fully proved and tasted for health and environmental effects. The Prodelec operation from France presented an approach which is an incremental modification of previous technology. For transformer use. they recommand keeping trichlorobiphenyl in mixtures with chlorobenzene. Both compounds of course. being chlorinated, have problems in that regard. Secondly, for capacitors they propose a mixture of dichlorobiphenyls and their alkylated derivatives, a commercial mixture of which is called chloralkylene. These products are now being examined by an 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 PC8 counterparts. Mr. David Wood from Monsanto Company described two new products, MCS-1238 and MCS-1588, for capacitor usage. He warns that neittirr is fire resistant although they have much better environmental characteristics. Their degradation is more rapid and their accumulation potential in the environment is considerably reduced. Occupational and environmental health considerations indicate a better product with lower acute toxicity. He also announced that they do have candidates with internv-cjuite f^e resistance between PCB's and mineral oil. but did not elaborate on this further. Dr. Dean Branson from Dow Chemical Com pany announced a substitute for use in power capa citors. This compound is called XFS-4169L and is a butylated monochlorodiphcnyl oxide. Once again we find that a substitute is like the original, a chlo rinated compound. Its properties are worth noting however. Dielectric losses are lower or slightly lower than for capacitor-grade PCB, while the discharge 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 166 centigrade, for XFS 174. The firepoint for PCB is greater than 316 centigrade, while XFS ts 199 . This substitute is reported to be more reliable and is anticipated to have a reasonable long-term pi ice. The increased expense is estimated to be less than $20 for a 200 kVAR unit. The capacity in the first quarter of 1976 should be in the range of 1 million pounds per year, and a multimillion pound per year volume capability is estimated by the end of 1976. This substitute is more biodegradable by a factor of 45 and the bioconcentration is 30 times less. There is little toxic activity in acute and in 90-day tests, although longer-term tests need to be carried out. The accumulation in fat is 22 times less. The toxicity in fish is on the order of 20 times less than for PCB's. 464 HONS 070119 carried out The accumulation in fat it 22 timai leu. Tha toxicity in fish it on the order of 20 times lest then for PCB's. * Perhaps the most exciting substitute for use in transformers was announced by Dow-Corniny (rep* resented by Richard Montgomery). He indicated that the global silicone industry had been looking for a replacement for the transformer fluid PCB's for 6 years, and the technology was now developed for the new fluid. It was to be commercially avail able in 1976 and had no l$iown environmental problems. Commercial produetion was available to handle the global market. In the United States thare has been field-testing jfor 4 years and the product is now ready to be used. The product is called oi-10 90 dielectric fluid, and is a dimethyl silicone which has been used in the military, in Japan, and in a small experiment in Midland, Michigan. He pointed out that this was not very dissimilar to "di-gel," which is used of course for human consumption. It it less flammable than many PCB's with low heat of combustion, high flashpoints and firepoints, 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 astimated 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. PCB 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 absence at the meeting might leave one with an unwarranted optimism for the use of these fluids in transformers. One further reflec tion is that we are badly in need of a frank assess ment of flammability risk requirements since the substitute products vary in their flammability over the great 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 and the possible damage to humans from substitute products which might gat into the envi ronment. It is also not clear that PCB's flammability characteristics should remain the benchmark for compliance although the insurance industries may see this differently. SUMMARY OP SESSION VI MR. CHRISTOPHER M. TIMM {Environmental Protec tion Agency, Region V, Chicago, Illinois): From a vary broad mixture of topics and points of views that we were listening to last night, I believe the following four points should be emphasized. First, on top of all the human health and wild life effects that have been documented and thor oughly discussed, PCB's are having a definite and drastic affect on the livelihood and future of the freshwater fishery and fishermen. This is a very real problem to the people in various parts of the 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, the actions of the regulatory agencies such as EPA and FDA must be based on scientific fact in the overall impact on the 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 impacted by environmental pollution which is PCB's. They do not cause the problem, they can not control the problem, and they often cannot find anyone to blame or even talk to about it. But they suffar the consequences of decades of incomplete evaluations and testing of new compounds. Thank you. 466 HONS 070120 SUMMARY OF SESSION VII MR. CHARLES N. GREGG, JR. (Environmental Protec- non Agency. Washington, Q.C.): Because most of /ou havo heard the discussion this morning, I will vy not to repeat it, but to provide some insights md perhaps some ot the highlights. I will not try to . jive equal time to the various speakers. First, there is an obvious distinction between uhyiical and technical methods of control, which have been discussed in other sessions,^nd the regu latory and voluntary actions for achieving those controls that were discussed by this morning's pan el Second, there is a distinction between the dircct control of human exposures as, for instance, through limitations on PCB's in fish that can be sold <w human consumption, and limitations on use or limitations on emissions into the environment, which in the long run contribute to diminished ex posure. In our present situation, as you were told by the speakers this morning, there are a vast number of Federal agencies with roles. Our Government and the Canadian Government both contribute to solu tions of the Great Lakes problem. We have a lot of SitQta Governments with roles to play. One of the major problems will be sorting out roles, and finding adequate cooperation in performing those roles, jmong the several agencies and units concerned. A further complication is that both in Canada ind here we not only have a number of regulatory juthorities now, but in each case we are looking for idditional authority which it is anticipated will per nt much more finely applied solutions. And at the sune time that we plan for the future, we do not know for certain what authority we v^jll have availal:le for use, One observation I made was that there seemed to be very little real optimism. If we applied all our available resources and used all of our authorities as best we could, we could solve in any short time frame the most pressing problem, which appears to he the high levels in fish in a number of places where they are caught and consumed in substantial quantity. This lack of optimism did not, neverthe less, suggest to the speakers that we should not take notion. Everybody seemed to agree that it was ap propriate to move ahead as best one could with the full range of authorities and voluntary programs iivai table. Also, there was considerable emphasis on nonrugulatory action, and increasing communication with people who have the opportunity to affect the flow of PCB's first from industrial situations into the environment and thereafter within the environ ment to locations where they can lead to highar human and environmental exposures. In my view, a voluntary program seems to present a very great op portunity for improvement, perhaps much greater than a strictly regulatory- program in the light of some of the difficulties experienced in using our cum nt authorities. Relatively less, it seemed to me, was said by th, morning's speakers about just hew to oontrol PCBh. particularly how to control, through regula te those PCB's which are currently in industrial uv elsewhere in products but not yet released gf- .i':v to the environment. There was some referer-r. t,j controls over disposal, but to my bast recollc : there was no indication that we had any d , applicable authorities with respect to dispor.. Let me touch on a couple of this morning's highlights. Dr. Ahmad of the NRDC assarted that the government had failad to carry out its responsi* bilities adequately, particularly under Section 307(a) of the Federal Water Pollution Control Act. He felt that we had a schedule on which we should have produced regulations a couple of years ago, with compliance a year ago, and ha criticized EPA's lack of attention and priority to toxics in our Water Pollution Control program. Ha made several recom mendations: a phaseout of the manufacture and use of PCB's, a ban on exports and imports, develop ment of an inventory of point sources, additional monitoring in fish and elsewhere, a moratorium on river bottom dredging until we have better indica tions of the trouble we stir up, effluent standards that would allow us to arrive at 1 ppt in water, lower FDA tolerance levels, end the passage of the Toxic Substances Control Act. Mr. Wessel of the Food and Drug Administra tion referred to its action in 1972 and 1973 to sat tolerance levels, indicating that various concerns had to be balanced in setting levels under Section 406 of the Food. Drug, and Cosmetic Act. He indicated that FDA was examining the current tolerance level in fish and considering whether or not to lower it. He said that there would be adequate opportunity tor public comment on any proposal that was made. But he felt that this would not solve the PCS prob lem and it would not necessarily prevent consump tion of fish with high levels of PCB's by private fisherman. 466 MGNS 070121 Dr. Kolbye of FDA added a discussion of some of the problems in setting tolerance levels, and something alt* I thought was significant: that step* art particularly naadad to idantify whara PCB's are located to we can look to their proper disposal, and education to this end is needed. He did feel that the average consumer it fairly well protected against. PCB's by tha current tolerance level, but acknowl edged that there would be higher exposures in some esses end that this was not a concern to pass over lightly. * Mr. Berber of the i^hvtronmental Protection Agency, after talking about some of our authorities and programs we have undertaken so far, gave cony siderable attention to some of the realities involved in EPA decisionmaking: the complexity and impli- cstions of taking various regulatory courses, and tha fact that there are limited resources in EPA, particu larly people, to handle a wide array of regulatory rasponsibiiitiet. He pointed our the importance of the Stitt rola, and indicated that tha Federal Gov ernment's role can bast ba viewed at one way of ancouraging the State to find ways to perform a greet deal of the regulatory and enforcement activi ty- He felt chat regulation must represent some sort of consensus and be enforceable in order to be pro ductive. He fait that a number of PCB problems were difficult to control because of the numbers of nonpoint sources. He urged that we try tor more awereness among the people who use PCB's, particularly the utilities, end suggested voluntary labeling and use of the planning process under Section 206 of the Federal Water Pollution Control Act. Secretary Read described both tha environmen tal problem caused by PCB pollution and tha result ing fisheries resource problem. High investment in restoring the Great Lakes fishery and future invest ment In this and other fisheries would be hard to justify unless we can control tha PCB situation. Ha suggtsted 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 wa cut off tha 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 level 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 been done. The Coast Guard has s number of functions under tha Federal Water Pollution Control Act in the event of. spills, but the Coast Guard representa tive told us that until we in EPA have designated PCB's as a hazardous substance, the Coast Guard is unable to go forward to use its authorities. He urged public awareness of the needs for good handling and precautions in transportation. Dr. Million of the Canadian Government 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 together 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 spoke last, and I have exhausted my time, with apologies to him I hope you remember what he said. 467 MQNS 070122 CONFERENCE HIGHLIGHTS Richard A. Carpenter* A lummiry of this complex and comprehensive con ference may bt mort useful if tht information is orga nized in tht format shown In tht accompanying figure (figurt 1). Tht prtstntations 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-ipadvertent human exposure, laboratory animal experiments, wild-, lift, 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 die reasons why a lack of understanding continues. Science is probabilistic in nature and this concept of uncertainty must be recognized when technical information is usad in deciding issues of public policy. 3. Finally, the conference discussions have sug gested some courses of action which are pru- 1. What Is known A. Occurrence in the Environment B. Toxicoloqy C. Uses, Benefits and Control 2. Remaining Uncertainties . 3. Prudent Actions Figure 1. Organization of information about polychlorinated biphenyls. *Executrv Director, Commiiaion on Natural Resources, National Research Council. Washington, D.C. 468 HONS 070123 dent, i.t., could and should be sat in motion. tion as to the role of air transport and the recirculation i These include setting priorities for otitaining of material that is deposited in rein or in dust beek into more information and reducing uncertainties the air so that it is continually redistributed around the through additional research and monitoring, world. The composition change of PC8's in the environ The conference was not designed to produce con- ment with aging is not well understood; there ere ques isnsus judgments nr to make recommendations. Thus, tions as to their chlorine content changing and regarding the following summary must be viewed as the responsi formation of diobenzofurens. bility of the author alone. We need a mass balance and a modal for transport and removal in order to estimate the time that will be A-1. What is known about the occurrence of PCBs in required for these materials to eventually move to an the environment We have learned what shouldfhave been apparent ultimate sink in the deep ocean sediments. A question has been raised as to the possible conver from the start-that any pprsiiteny mobile, and foreign sion of these materials into higher chlorinated com or exotic compound is going to be detected everywhere pounds during sewage chlorination. in the environment. In addition to current production We need to know more about the presence of the ind uses, which may result in leaks, a nonpoint source materials in whole water; i.e., are we measuring material situation exists in that about 400 million pounds of on suspended sediments, in very small organisms, in PCB's are already discarded in the environment and sub micelles, or actually dissolved in water? We need to stantial amounts are apparently recirculating in sludge, know about the biological activity of these various forms sediments, in air and dust, and in contaminated orga- of occurrence of PCB's in water. nisms. There are about 300 million pounds in industrial A 3. Prudent actions rvice and this material will ba difficult to contain com What can we do based on this information and pletely as it moves toward disposal. The sediments in uncertainty? We can separate, to some extent, the prob lakes, rivars, and estuaries provide a very large reservoir lem of what is already in the environment from the con of PCB's for contacting aquatic organisms. The material trol of material that has not yet been released. Even if ail in dumps (thraa-fourths of the total discarded) appears manufacture end use were stopped immediately, envi to stay there for the most part. Current processing losses ronmental contamination would remain for some time sre important and can be decreased. to come. The PCB problem should be considered in the Eventual removal is to sediments in the deep ocean context of other haiogenated hydrocarbons in the envi snd we need to know more about the fate of this mate ronment end it should not be separated from investiga riel in the marine environment. tion and control of the residues of pesticides and other It is too early to see the effects of the 1972 volun haiogenated materials. Work shoutd begin on e more tary action to limit uses to nondispersive applications, systematic monitoring system and on the use of indica but certainly it was a justified decision and a move in the tor organisms, such as the suggested "mussel welch," on fight direction. a worldwide basis. There will be occasional catastrophic spills which cen cause substantial damage to fisheries in the future. We can use some ingenuity in devising means of cleaning up contaminated water. This problem is of These will be localized impacts, and will be costly to magnitude that allows one to think about filtration or clsin up. adsorption concepts for waters that art somewhat con Incineration is an effective method of destroying ^CB't if the temperature is high enough (i.e., about fined. Ingenuity may suggest ways to make contaminated *.700 F). fish suitable for use in animal feeds or human consump Analytical procedures now give confidence that we tion. Perhaps segregation of certain organs or particular ton measure PCB's qualitatively and quantitatively down methods of cooking would serve this purpose, or some to few parts per trillion. other way of decontaminating these valuable animals might be found. Uncertainties about PCB's in tha environment There is a real question as to whether the PC8 con B-1-. What is known about toxicity G of the waters of the Great Lakes (particularly Lake The Yusho incident proved the toxicity of used heat **'igin) can be lowered by any degre. of tightening-up 01 tot current use situation, because of the recirculating transfer fluid to humans at a concentration in cooking oil of about 1,000 ppm of PCB's. But interpretation of Gemination that is already there. There is the ques- this incident is confounded by dibenzpfuran contamina- 469 *ONS 0701*4 tion of the FCB fluid. Industrial hygiene experience is somewhat reassuring as to toxicity to humans except that the occasional symptoms and illnesses cannot be related to known exposure doses in most instances. The good housekeeping practiced by some large users and the American manufacturer will probably be better then thet of the variety of secondary users. No human deaths have baan causad directly, but reports of serious illness and persistent skin problems continue. 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.ijAverages for die* tary intake can be misleading, since some persons may cat large quantities of fish. Laboratory animals show effects when fed diets containing contamination levels found in fish. Fish are effected at the range of PC8 levels found near industrial outfalls into ambient waters, and the occurrence of fin r<: t in fish near these "hot spots" is a direct confirmation o! laboratory tests as to the effects on fish. Ecosystem simplification (fewer species and lower populations) has been found in laboratory experiments t<: occur at concentrations similar to those in hot spots in natural ambient waters and could be expected to be found at sludge disposal sites. It is hard to find evidence of damage to terrestrial ecosystems. Biomagnification, i.t*.. the ratio of the PC8 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 problems of ascertaining carcinogenicity could t worked out by those scientists involved apart from thti complexity end emotionelism of a specific issue such at the PCB problem. The effect of dibenzofurans, which may be present as impurities or as metabolites, is still in question. There is a great variation as to the response of difftunt species in laboratory animal tests. The range of sensitivity is large. More needs to be known as to whethor the reproductive problem is the most important ef fect. Fat metabolism is not well understood end since a gr<>at proportion of the human population is carrying around a few ppm of this material, we need to know more about it. Wildlife toxicity data is poor and we need to know which wildlife species may react as 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 biomagnification from water to the first orga nism? 8-3. 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 change in animals, and laboratory work at true environmental levels, rather than to greatly increased levels of dose. Obviously it is of great impor tance io determine unequivicaily whether the PCB mate rials an- carcinogenic W-1 neprl to coordinate this work with experiments and observations on other halogenated hydrocarbons. pan.cuiariy the chlorinated hydrocarbons, and to look at combined effects on organisms, communities, and ecosystems. NIOSH should extract the maximum from industrial hygiene data 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 an inadvertent experiment on human populations and the biosphere. A concerted effort at monitoring and analysis is indicated in order to gain the most useful knowledge for further decisions concerning toxic substances at low levels in the environment. C-1. 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 annual produc tion volume is down to 40 million pounds from an 80 million pound level in 1970. About one quarter of pres ent production is going into small capacitors that are scattered very widely throughout our industrial society. The fire retardant benefits of PCB's are 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 have a substantial transition period. Forty-five years of use has imbedded PCB's in U.S. industrial practice and it will be costly to replace these unique materials. Alternative dielectric fluids are on the way, but will not be suitable as replacements in existing transformers. 470 HONS 070125 C-2. Remaining uncertainties The decision by Japan 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, frhy cannot we? Is a total ban worldwide necessary in order to re duce and eliminate contamination to the North Ameri can environment7 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.. dibenzofuren formation. How nondispersive are "cios ed" electric systems? $ We need to recrticlle the differences in human foo't tolerance limits as established by the United States ppm) end Canada (2 ppm) and in alternative/proposai* from various protagonists on all sides of that questicr Cost/benefit analysis will not be very helpful in ti PCS contamination problem because of the great nun> ber of subjective judgments and different value system involved in arriving at a balance. In any event, the man; nal costs and the marginal benefits are what must t determined. We need to know how to remove PCB's from waste water, i.e., what would bt best practicable technology economically achievable in order to get to an effluent standard, and whether that should be 5 ppb, or zero, or what level. We need to know whether 1 ppt is a reason able ambient water standard in view of the large bio magnification factor. C-3. Prudent actions EPA has a responsibility to determine priorities and it needs to review the PCS issue in terms of the total set of pollution problems end the agency's resources. EPA should proceed with effluent standard possibilities in Section 30? of the Water Quality Act (PL 92-500), although such action may and up in court tests. The Endangered Species Act may ba 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 fisharmen may 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 e reel 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 industrial 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 wa all shart, in this case there may be a coincidence, in 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 as well as in working on an ultimate solution for the problem as a whole. 471 HONS 0701.26 TECHNICAL REPORT OATA (Please read Mtuuctionx on the reverse before completing) I REPORT NO. EPA-560/6-75-004 2. 3. RECIPIENT'S ACCESSION NO 4 riTcR ANO SUSTITlE National Conference on Polychlorinated Biphenyls (November 19-21, 1975, Chicago, Illinois) 5 REPORT OAT! March 1976 6. PERFORMING ORGANIZATION COOE 7 AUTHORiS) Franklin A. Ayer (Compiler) 9. MMONMING ORGANIZATION NAME ANO ADDRESS Center for Technology Applications Research Triangle .Institute P.0. Box 12194 I Research Triangle Park, North Carolina 27709 13. SPONSORING AGENCY NAME ANO ADDRESS Office of Toxic Substances Environmental Protection Agency Washington, D.c. 20460 15. SUPPLEMENTARY NOTES EPA Project Officer - Shanas Kopp 18. AiSTRAdt - - - B PERFORMING ORGANIZATION REPORT NO. io. pr6(JrAM CLEMENT NO. 11. coMract/grant &o. 68-01-2928 13. TYPE OP REPORT ANO PIRlOO COVERED Proceedings Nov. 14. SPONSORING AGENCY COOE " The objectives of the conference where to bring together the latest data and best available expertise to help clarify the problem associated with the I 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 ocnplicaticns of steps to reduce the problems associated with PCBs. O KEY WORDS ANO OOCUMfNT ANALYSIS DESCRIPTORS b. 1OENTIFIERS/OPEN ENDED TERMS c. COSATi Field/Croup Polychlorinated Biphenyls (PCBs) PCB Health Effects KB Human Exposure PCB Uses. Sources. Identification KB Environmental Fate K3 occurrence 1 S3 Ecological Effects 6 Exposure |7^TR^^r?VSTfM?NfUett51,4"B 1 i *'* Srm 1220-1 11-73) 19. SECURITY CLASS (This Report) 30. SECURITY CLASS (This page) 31. NO. OF PAGES LR7 33. PRICE HONS 07012? Errata Sheet Pg, 315 Change Para. 2 Line 8 "and for XFS 4169L KW'C" to read 174"C HONS 070128 I til* UNITED STATES [*: environmental pnotection agency OfflM sf Task CiiMwcm WMiitaftt*. 0. C. 30N0 OFFICIAL BUSINESS An equal offortunity emfloyer POSTAGE AND FEES FAIO U.S. ENVIRONMENTAL PROTECTION AGENCY EPA335 \ Return thk sheet if you do NOT wish to rsosive this mstsrisU I, or if change of address is neededT~l. (Indicate change, including ZIP code) Mr. William Papageorge Manager Product Acceptability Specialty and Processing Chemicals Monsanto Industrial Chemicals Company 800 North Lindbergh Boulevard St. Louis, Missouri 63166