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f t . *. POLYCHLORINATED DIPHENYL BIODEGRADATION STUDIES '^The,threat of continued accumulation of polychlorinated biphenyl (PCB) residues in the environment is responsible for much of the apprehen sion about the future use of these materials. Examination of the i data collected to date from both external and internal PCB residue l monitoring programs has confirmed chat at their previous rate of I release some persistent PCB homologs have begun to accumulate in the Leco-systenwjTconversely, it can also be stated that, with the excepf ti07r-of^irect high level controllable contaminationi][.PCB homologsi c with less than 5 chlorine atoms have not accumulated in the eco- * system|7although they have been released in an unrestricted fashion |) for many years. ^ o TxdU+t. I This observation indicates that at the previous rate of release an environmentally compatible PCB product would be one containing no PCB homologs with greater than four chlorines per molecule. As has been previously stated, it is not commercially feasible to produce a product completely free of the pe rsistent _homo jogs. However, it is technically feasible to produce an industrially useful PCB product, Aroclor 1016, which contains significantly (10 to 20 times) lower levels of these persistent homologs. Two questions remain which must be answered, first to what degree is biological degradation responsible for the disappearance of the "non-persistent" PCB homologs, and secondly, with controlled and restricted usage, will Aroclor 1016 be environmentally compatible. In an attempt to answer these questions, a number of comparative experimental laboratory studies of the Aroclor products have been carried out to determine the extent to which these materials are degraded by bacterial, avian, mammalian, and aquatic organisms. Bacterial Degradation - Semi-Continuous Activated Sludge (SCAS) Degradation Studies of Polychlorinated Biphenyls Introduction The semi-continuous activated sludge (SCAS) test procedure used to study the primary bacterial degradation2 of polychlorinated biphenyls is patterned after the test method recommended by the sub-committee on biodegradation test methods of the Soap and Detergent Association for the evaluation of surfactants*. This procedure employs sludge from a sewage treatment plant as the source of microorganisms. A specific amount of the material being studied and a synthetic sewage mixture* are fed, on a periodic basis to the activated sludge in a specially designed aeration chamber. Aliquots of the mixed liquor (sludge + water) are withdrawn from the chamber shortly after feeding and near the end of the aeration period and analyzed to determine the disappearance rate of the test compound. This cycle is continuously repeated until a steady state5 is achieved and consistent biodegrada tion rates are obtained. Details of the procedure may be found in the attached Analytical Chemistry Method 71-32. NfcV 027^76 ) y\cf - 2- '?'? SCAS testing of Aroclor 1254, Aroclor 1242, Aroclor 1016,CMCS 1043 and Aroclor 1221 were carried out over an eight-month period^ Disappearance rate data were obtained during two sampling 3pp<eriods for Aroclor 1254, Aroclor 1242, Aroclor 1016, and (fics 104T_lj>) For Aroclor 1221 only one sampling period was employed? In the initial testing of these materials, a feed rate of 1 mg per 24-hour cycle-- ` was used. Because the data obtained from the first sampling period for ail PCBs studied, except Aroclor 1221, were extT`PTnolY with little apparent biodegradation, the exposure period between additions of the test material was extended to 48 hours for all materials except Aroclor 1221. Mean disappearance rates and 95% confidence limits obtained via statistical analysis of the data from the last sampling period are shown in Table I. TABLE I Test Material % Cl (w/w) Exposure Period(Hrs) Mean Per Cent Disappearance Rate (Uncorrected) Aroclor 1221 MCS 1043 JAroclor 1016 Aroclor 1242 Aroclor 1254 21 30 ------ 41 42 54 24 4B 48 48 48 64- 1 3 -6 56.2 + 15.5 32.9 + 13.8 26.3 + 15.5 15.2 + 37.7 It is apparent from inspection of Table I that degradation decreases as the degree of chlorination increases and that because of the uncertainty in the data that it is not possible to differentiate between Aroclor 1242 and Aroclor 1016 with respect to degradability at the 95% confi dence level. This is not surprising since Aroclor 1016 constitutes h ^80% of Aroclor 1242 and the resolving power of the test procedure is Subsequent- SCAS testing of^Aroclor 1221 at a feed level of 1 mg was carried out to establish tSw^Blgnlflcanoo ef-volatility leases ; the effect of exposure period# ami Llm repraauclbi.ilLy o f the testprocedure. The results obtained are shown in Table II. 'A i *\ TABLE I I Aroclor 1221 Exposure Aeration Period(Hrs) Rate (CFH1 Volatility Losses () Mean Per Cent Disappearance Rate Uncorrected- - ?__ Corrected 24 0.5 16.1 74.9 + 7.7 24 0.1 24 0.1 4.5 69.9 + 17.8 81.0 + 18.6 48 0.1 80.6 + 5.7 The data in Table II demonstrate that volatility losses can and do occur and that these losses are a function of the aeration rate and hence also the vapor pressure of the test material in question. It MEV 02 72 77 740532 i* > * / a/**' r is, therefore,-treasonable to ^ s.g^ipgJ-,fthat as the degree of chlorination increases that volatiil-ty iosseB would become insignificant. The fact that the corrected disappearance rates do not vary with aeration rate also indicates that the volatile components of Aroclor 1221 are subject to degradation and that even if they were not lost in this manner they should not appreciably effect the observed degradation rate. The mean uncorrected Aroclor 1221 disappearance rates for the 24-hour and 48-hour exposure periods were for all practical purposes i equivalent, establishing that when dealing with complex mixtures, a 1 simple linear extrapolation of disappearance rates as a function of exposure period is not valid. Electron-capture gaB chromatography analyses of samples taken at the end of the aeration cycle showed that the lower level of chlorination the greater the changes In the homolog distribution. For Aroclor 1221, the dominant monochloro- and dichlorobiphenyl homologs almost completely disappear after 24 hours of exposure to activated sludge. Similar changes in the ratio of the higher chlorinated homologs to lower ones were noted for the other PCBs studied with the exception of Aroclor 1254. For Aroclor 1254, no significant change in the homolog distribution was observed. At the feed levels employed, no toxic effects toward the activated sludge were observed for any of the test compounds. /)JUL v- tCpU ta- Results and Discussion The sampling and analytical procedures employed in the disappearance rate determination of a test compound during a cycle were as follows: A 20-ml sample of the mixed liquor (activated sludge + liquor) was withdrawn one hour after feeding and at the end of the aeration period. The sample of mixed liquor was then extracted and the extract concentrated according to the procedure given in Analytical Chemistry Method 71-18. The concentration of test compounds was then deter mined either by an ultraviolet (UV) spectroscopic or electron-capture gas chromatographic (EC-GC) method. Details of the UV methods are given in Analytical Chemistry Method 71-17 and the EC-GC methods in Analytical Chemistry Method 71-35. The disappearance rate was calculated from the following equation: C -C I Disappearance Rate -- =-- X 100 Where CQ level of test material present after feeding C level of test material present after n hours of exposure NEV 027276 740533 <0 - 4 - Tests were carried out to determine if quantitative recovery of the various test materials from the mixed liquor was achieved by the extraction procedure- Details are given in Analytical Chemistry Method 71-17. Although complete recovery was not achieved in all cases, the recoveries were consistent and independent of concentra tion level. The calculated disappearance rates Bhould, there fore, not be affected significantly. Since the level of chlorination is the most significant factor in the relative biodegradability of the PCBs, the homolog distribution of the various test materials is given in Table III. TABLE -III S p s .f i ? . HOMOLOG DISTRIBUTION OF POLYCHLORINATED BIPHENYL PRODUCTS l** Homolog No. of Cl Per Biphenyl Molecule 0 1 2 3 4 5 6 7 8 9 10 Aroclor 1254 (54% Cl) 0.05 0.06 0.32 0.78 22.99 47.3B 19.75 4.62 3.96 Aroclor 1242 (42% Cl) 0.01 0.70 15.50 49.40 24.80 8.70 0.85 MCS 10X6, MCS 1"0S43 ] Aroc/lor (41% Cl) (30% Cl) / (21% Cl 0.02 1.00 19.70 57.30 21.20) 0.8 0 L 0.0511 0.11 / 23.4 / 71.3 I 5.2 / k .J I 19.00 54.10 20.40 3.90 2.30 0.25 y# Feeding of the Aroclor 1254, Aroclor 1242, Aroclor 1016, and MCS 1043 unitB was started on 8-10-70 at a feed level of 1 mg per 24-hr cycle. These units were sampled for approximately one month starting with the first day of feeding. All analyses were carried out by electron-capture gas chromatography. The data obtained were extremely erratic. A statistical analysis of the data (Statistics Special Study 70-22) using the Student's t test indicated that at C. the 95% significance level, only MCS 1043 showed evidence of bio degradation. Both Aroclor 1016 and Aroclor 1242 showed some evidence of biodegradation, but neither was significant at the 95% level. Aroclor 1254 showed no evidence of biodegradation. In order \ to detect biodegradation at the 95% level of significance in 20 observations, about one-half of the test materials must be degraded i in a cycle. The lack of significant biodegradation during the first sampling period was. probably due in part to the need for an acclima y tion period by the bacterial sludge. Subsequent spot checks on the unit, however, indicated that the data obtained were still erratic. Because of the apparent slow rate of biodegradation of these materials, the cycle time was increased to 48 hours in the hope that larger differences would be observed between the before and after feeding samples. NEW 027279 740534 -5- Qx*. Jo Feeding of the Aroclor 1221 unit was started on 10-27-70 at a feed level of 1 mg per 24 hours. Aroclor 1221, because of its higher rate of disappearance was maintained on the 24-hour cycle. Sampling of the unit was started 1-25-71 and completed 1-29-71. Analyses were carried out by electron-capture gas chromatography. The final sampling period for the Aroclor 1254, Aroclor 1242 Aroclor 1016, and MCS 1043 units at a fped -rate of l^aug~-pgI''~~48-hour cycle was started 2-8-71 and completedQ - 8 - 7 1 ^ 3 "BoKuv and EC-GC analyses were carried out; the UV data was used to determine the overall disappearance rate and the EC-GC to monitor the change in homolog distribution. In Figures 1-1 to 4-2, the observed data from which the mean disa ppearance rates were calculated are shown for both sampling periods for Aroclor 1254, Aroclor 1242, Aroclor 1016, and MCS 1043. In Figure 5, similar data for Aroclor 1221 is shown for a single sampling period. In the top chart of each figure the total mg found in the unit at the beginning and end of each cycle is plotted versus the elapsed time in days after the start of the test. The after feeding sample is denoted by the solid circle; the before feeding sample by the arrowhead; the connecting line indicates the amount lost during each cycle. In the lower chart of each figure, the disappearance rate obtained is plotted versus elapsed time. In Table IV the mean disappearance rate and 95% confidence limits obtained for the test compound during the various sampling periods are given. Since the analyses for Aroclor 1221 were carried out by EC-GC, the disappearance rate does not include any decrease in the biphenyl component (see Table H I for Aroclor 1221 composition). P 1 TABLE IV SCAS MEAN DISAPPEARANCE RATES FOR POLYCHLORINATED BIPHENYL PRODUCTS* y- w / u "\S * Sampling Period/ _____M_e_a_n__D_i__s_a_p_p_e_arance Rate +95% .Confidence Lin^tB Cycle Time Aroolor--1354-- Arocior^l^fe M?S l6l6 HS5 ib4XT Aroclor 1221 1/24 Hours -29. 0-H5B, 11.0+19.5 3.6+19.0 4 .7+22.0 J) 2/24 Hours 64.0+13.6 3/48 Hours 15.2+37.7 26.3+15.3 32.9+13.8 56.2+15.5 r c Identification of feed material in SCAS tests Aroclor 1254 Aroclor 1242 Aroclor 1016 MCS 1043 Aroclor 1221 Lot AK-38 Lot AK--255 Sample No. 1, OR 158591 Sample No. 2, OR 158591 Lot AK-2 ~PC6<!\ 8 S NfcV 027250 740535 e 6- In order to make certain that the observed disappearance rates were not due primarily to volatility lossesr scrubbing experiments on the most volatile test material, Aroclor 1221, were carried out in which the off-gases from the units were passed through a series of three hexane scrubbers during a complete time cycle. Data were obtained at both 0.1 and 0.5 SCFH aeration rates. The data estab lished that at the 0.5 SCFH air flow volatility losses were ^16%, at an aeration rate of 0.1 SCFH the volatility losses were reduced to ^5%, while the overall disappearance rate was essentially the same as that obtained at 0.5 SCFH. This means that the components lost by volatilization are for all practical purposes completely degradable and the disappearance rate (64.0%) obtained represents actual biodegradation. Since the volatility of the PCBs decreases with increasing level of chlorination, the volatility losses should likewise decrease. From the volatility losses observed for Aroclor 1221, one would not expect such losses to be a significant factor in test disappearance rates for MCS 1043, Aroclor 1016, Aroclor 1242, and Aroclor 1254. From the data in Table IV and Figures^l-l, 2-1, 3-1, 4-1, it is quite apparent that the disappearance rate data obtained for Aroclor 1254, Aroclor 1242, Aroclor 1016, and MCS 1043 during the first sampling period was very erratic. The data obtained during the last sampling period as shown in Table IV and in Figures 1-2, 2-2, 3-2, and 4-2 was a significant improvement. From the latter data, the following ranking in terms of biodegradability can be made: Aroclor 1221>MCS 1043>Aroclor 1016^ JU\ Aroclor 1242>Aroclor 1254 V- r ITnn PFilgnnurroe 6, the mean disappearance rate is plotted versus the per cent chlorine in the test compound. The mean per cent disappearance rate for biphenyl was obtained in a previous study (Statistics Special Study 71-2) It is apparent that the disappearance rate decreases with increasing levels of chlorination. As was previously noted, selected samples from the last sampling period were analyzed by EC-GC to monitor changes in homolog and isomer distribution. In Figure 7, chromatograms for Aroclor 1221 are shown. The top trace is a chromatogram of an Aroclor 1221 standard representative of the feed material. The center chromatogram is that of a sample taken at the end of the exposure period or aeration cycle. The bottom chromatogram is that of an Aroclor 1242 standard run under the same GC conditions as the other chromatograms. The numbers above each peak indicate the dominant homolog represented by that peak according to GC-mass spectroscopic determination. NEV 027231 740536 -7- It is important to note that the electron-capture detector does not have the same response for all components. The sensitivity of the detector generally increases as the degree of chlorination increases. From the chromatograms in Figure 7, it is apparent that the dominant monochlorobiphenyl and dichlorobiphenyl components of Aroclor 1221 have almost completely disappeared after a 24-hour cycle, while there 1b an apparent buildup of the minor higher chlorinated isomers. These minor components, because of the increase in detector sensi tivity with chlorination level, are amplified in the chromatograms compared to their true weight per unit basis. Comparison of the extract chromatogram to that of the Aroclor 1242 standard shows that these minor components in Aroclor 1221, which are more resistant to degradation, comprise the major components of Aroclor 1242. In Figure 8, similar chromatograms are shown for MCS 1043. Comparison of the extract chromatogram to that of the standard again shows that the lower chlorinated isomers or homologs disappear more rapidly while a buildup of higher chlorinated components occurs_________ ___" " ,,7 -- 1 .1*1 JIn Figures 9 and 10 chromatograms for Aroclor 1016 and Aroclor 1242 extracts and standards are shown. With these more highly ,,chlorinate d ' products, the change in homo log distribution are n o a s dramatTc^coTTT^ pared to the lower chlorinated products. The buildup of the more refractory penta- and hexachlorobiphenyl homologs is apparent. For Aroclor 1254, chromatograms have not been included since no significant change in homolog or isomer distribution was observed during the testing period. At the conclusion of the final sampling periods for Aroclor 1254, Aroclor 1242, Aroclor 1016, and MCS 1043, feeding of the test compound was stopped. The units were then monitored over a period of time to determine how rapidly the residues remaining from the various test compounds disappeared. In Table V, the mg of residue found at various time intervals after the last feeding are shown. As expected, the lower the level of chlorination the more rapidly the residue disa ppears For Aroclor 1254, it is apparent that no significant decrease in the residue occurred over tne period studied. X l l w-rJLsu Days After Last Feeding Test Compound 3 5 7 10 TABLE V ________________ Mg of Residue Aroclor 1254 Aroclor 1242 MCS 1016 MCS 1043 5.38U* 0- 4.SO) 4.94 ' 7.42 *?? 2.627^.1. J* 2.29 1.47 ' 1.76 2.26 1.16 1.31 1.17 1.24 1.06 0.70 0.75 NEV 0^7282 740537 a -8- ReBidae Studies for P o ly ch lo r in a te d B ip h en yls f P C B a ) in F i s h . D ird s and M a m m a ls Introduction Early in 1969, after confirmation of Jensen's6 identification of PCB residues in Swedish birds and fish, Monsanto began initiating a series of Aroclor toxicity-tissue residue studies. The general objective of these studies was to learn more about the environmental behavior and .potential effects of PCBs. As indicated by the title of this appendix, it will deal only with the results of the residue work. Appendix should be consulted for the results of the toxicity work. The specific objectives of the tissue residue studies with fish, birds and mammals were to learn more about: 1. tissue storage levels as a function of exposure time and exposure level, 2. the character of the PCB residues retained from the various Aroclor products, and 3. the rate at which PCB residues disappear once exposure ceases. To date, analyses of tissues collected from nine7 toxicity-tissue residue studies have been completed. The tissue samples were collected, quick frozen, and shipped by the consultant laboratories to Monsanto Industrial Chemicals Company. Upon receipt, the tissues were analyzed for PCB residues by Monsanto personnel in accordance with Analytical Chemistry M e t h o d *71-35. In the first two tissue collection studies all samples were analyzed. In the subsequent studies, a statistical approach was employed because of the large number of samples In this manner, both the elapsed time and manpower requirements were minimized with little real loss in either accuracy or precision. The approach involved analysis of a balanced sub-set (^25-30%) of the tissues collected. The data from the balanced sub-set of samples, the appropriate study variables (tissue, exposure period, exposure level, sex, and Aroclor f e d ) , and the most probable variable interactions were then used to generate an interpola tion equation via multiple regression-analysis. The initial equation was then smoothed by deleting data more than two standard deviations from the predicted values and the variable interaction terms not significant at the 95% confidence level. The final equations were then used to calculate the PCB residue levels in the un-analyzed tissues. The validity of each of the predicting equations was established in the following manner. The respective residual standard deviations of each equation was compared to those obtained for the equations developed for the two studies in which all samples were analyzed. The 95% confidence limits calculated for these studies from the log of the residual standard deviations indicated that in all studies the actual values determined by analyses would be M).5-2 times the predicted values. NEV 027283 740538 9 '* S -9 Summary and Conclusions The most significant conclusion which can be drawn from these residue studies is that it supports what has and is being observed via residue analysis of environmental samples. That is to say, that from a "residue viewpoint", the bulk of the PCB isomers which have been released to the environment (PCBs with less than 5 chlorines) are subject to degradation. Since degradation of these PCB isomers can and does occur at significant rates they in turn should not be a long term threat to the higher members of the food chain. In Figure 11, the observed PCB residue levels for rats and dogs exposed to Aroclor 1221, Aroclor 1242, Aroclor 1254 and Aroclor 1260 for 90 days is plotted vs the degree of chlorination of the product fed. It graphically illustrates that PCB storage levels decrease exponentially as the degree of chlorination of the product decreases. This exponential decrease simply reflects the refractory PCB content of each product produced via direct chlorination^ Considerable differences were noted in concentration factors as judged by the ratio of the PCB level found in the extractable lipid to the exposure level. Fish were found to be most efficient PCB concentrators followed by chickens, rats and then dogs. The calculated concentration factors observed for Aroclor 1242 are shown in Table VI. TABLE VI Blue Gills Catfish White Leghorn Chickens Albino Rats Beagle Dogs Exposure Level(PPM) 0.1 in wtr. 0.1 in wtr. 1.0 in feed 1.0 in feed 1.0 In feed Exposure Period 21 Days 21 Days 12 Weeks 2 Years 2 Years Max. Observed PCB Level in Lipid 4.0% 3.2% 20 PPM 9 PPM 2 PPM Concentration Factor* (pp 400,000 320,000 20 9 2 NOTE: Factors do not take into account exposure periods Calculation of concentration factors in this fashion for chickens, rats, and dogs can be misleading. For example, ratio of total PCBs retained to that orally ingested by chickens, rats and dogs is shown in Table vil, TABLE VII Test Material - Aroclor 1242 White Leghorn Chickens Albino Rats Beagle Dogs _____ Exposure Level 1 PPM 10 PPM 100 PPM 0.11 0.02 0.005 0.11 0.01 0.001 0.11 0.003 0.0003 l O * ^ \SLy- NEV 027284 P " ' ," s;- ?4053g  - 10- Inspection of the ratios illustrates that the higher members of the food chain are in fact inefficient PCB concentrators. Decrease of PCB residues was noted with both chickens and dogs placed on PCB free recovery diets. The dogs remobilized the residues more rapidly than chickens. In both studies, the residue levels fell more rapidly the lower the degree of chlorination of the product fed. Figure 12 illustrates this point. In it the % total PCBs accumulated in the lipid is plotted vs the recovery periods for the Two Year Beagle Dog Study with Aroclor 1242, Aroclor 1254, and Aroclor 1260. Figures 13-22 are bar graphs constructed from electron capture gas chromatograms of the product fed and the isolated PCB residues. The bar graphs were constructed by normalization to a convenient peak present in each of the chromatograms being compared. The numbers above each bar indicate the dominant homolog or homologs as determined by mass spectrometry. In no case were the residue fingerprints observed to be a function of the exposure level. Figures 13-15 compare the distributions observed for residues isolated from fish, chickens, rats and dogs exposed to Aroclor 1242, Aroclor 1254, and Aroclor 1260. Inspection of these figures demonstrates that fish absorbed Aroclor 1242 without altering the isomer distribu tion. Dogs were found to be most effective at selectively degrading the Aroclor products followed by rats and the chickens. The figures also indicate that, with minor exceptions, the lower chlorinated isomers present in each product are more easily degraded. Figures 16-18 illustrate the make up of the residues isolated from dogs after 2 years of continuous exposure followed by 30 and 60 day recovery periods on PCB free diets. Inspection of these figures reveals that the bulk of the isomers observed in the dogs sacrificed after two years of continuous exposure rapidly degraded once exposure ceases. Figures 19-21 illustrate the alterations observed when chickens exposed to these three Aroclor products for 12 weeks were placed on recovery diets for 30 days. Although the degradation was less extensive than observed with dogs, the same general trends were noted. jin Figure 22, the isomer distribution of Aroclor 124 2 and the residues isolated from rats fed Aroclor 1242 and Aroclor 1016 for 90 days are shown. Although the difference in the total % chlorine in these products is negligible the isomer distribution of the residues are significantly different. This difference can be explained by the fact that the higher chlorinated biphenyl content of Aroclor 1016 relative to Aroclor 1242 has been reduced by a factor of twenty. The actual residue levels as determined by analysis and interpolation are shown in Tables VIII - XXXII. NtV 027265 740540 REFERENCES 1. Bagley, G. E . , Riechel, P., and Cromarite, E . , J. of AOAC 53 (1970) 252. .Armour, J. A., and Burke, J. A., JAOAC, 53 (1970) 761. Zitko, V., Bull. Environ. Contamin. Toxicol., (1971) 464. Reynolds, L. M., Residue Reviews, 3 (1971) 27. Prestt, I., Jefferies, D. J., and Moore, N. W . , Environ. Pollut. 1 (1970) 3. Tas, A. C., deVos, R. H., Environmental Science and Technology, 5 #12 (1971) 1216. Duke, T. W., Lowe, J. I. and Wilson, A. J., Bull. Environ. Contain. Toxicol., 5 (1970) 171. 2. Primary Bacterial Degradations "Minimum alteration of the chemical structure of the material in question to an extent that the characteristic properties of the original material are no longer evident". 3. Biodegradation Subcommittee. JAOCS 4_2, 986 (1965) ; JAOCS 6, 432 (1969) . 4. Synthetic Sewage: 30g. dextrose, 20g. nutrient broth, and 13g. dipotassium hydrogen phosphate in one liter of water. 5. Swisher, R. D., Surfactant Biodegradation, Marcel Dekker, Inc., N.Y. (1970) pp 173, 175-186. 6. Jensen, S. (1966) "Report of a New Chemical Hazard", New Scientist (32) 612. 7. IBT B7009 30-Day Tissue Collection Study In Albino Rats with Aroclors IBT B7296 Two-Year Chronic Oral Toxicity Study of Aroclor 1242, Aroclor 1254, Aroclor 1260 in Albino Rats IBT P7297 Three-Generation Reproduction Study in Albino Rats with Aroclor 1242, Aroclor 1254, Aroclor 1260 IBT 9888C 90-Day Subacute Oral Toxicity Study of Aroclor 1016, 9888D Aroclor 1221 in Albino Rats IBT C7299 Two-Year Chronic Oral Toxicity Study of Aroclor 1242, Aroclor 1254, Aroclor 1260 in Beagle Dogs IBT 9887 90-Day Subacute Oral Toxicity Study of Aroclor 1016, 9885 Aroclor 1221 in Beagle Dogs NfcV 027286 740541 -12& 7. Continued _ XBT J7300 Toxicity, Reproduction and Residue Study of Aroclor 1242, Axoclor 1254, Aroclor 1260 in White Leghorn Chickens IBT 8746 Toxicity, Reproduction and Residue Study of Aroclor 1242, Lot IAK-255 in White Leghorn Chickens The following study was carried out at Bionomics, Inc. of Wareham, Massachusetts. Acute Toxicity of Aroclor 1016, Aroclor 1242, and DDT to Bluegill and Channel Catfish During 21 Days Continuous Exposure to the Chemicals in Water. > 740542  L > *t ) . \ Q ^ c ' -4 V bcc: B2SA B25A B2SL B2NK B2SH 1010 T3A I76O I76O ' ^>1760 Mason--- H. S. Bergen T, L. Gossage W. B. Papageorge C. Patn R. A. Garcia W. R. Richard R. H. Munch Scott Tucker R. Keller October 13# 1971 Dr* Tom Bakin Westinghouse Electrio Beulah Road Pittsburgh# Pa, Bear Toms Thanks kindly for telephoning today to relate questions arising from various plaoes within Westinghouse regarding the environ mental acceptability of Aroolor 1016 and Monsanto's corporate posture regarding this material. We especially welcome your call as indeed we have been seeking . to bring responsible executives of Westinghouse up to date about thlB, Our biological studies continue as intensively as possible within Monsanto and also in collaboration with outside agencies. The findings continue to be increasingly encouraging. Our people welcome opportunity to present all detallo of this bio.logical work and to discuss the practical implications which help to support our corporate policy to continue the supply of this material to meet the requirements of the electrical in dustry, We will also want to review the collaborative program now oentered at ANSI to establish and distribute, guide lines for handling scrap rCBs* We have removed the higher chlorinated and the more refractory PCBs from our dielectric fluids and have discontinued marketing PCBs for non-electrical and open system purposes, Whilo ve continue to market for electrical use In sealed systems# Mon santo oan no longer carry this program alone, V/e need support and testimonials from the electrical manufacturers and users. Accordingly# we welcome your proposed visit by responsible executives# early in November, Please nominate suitable nates and let us know who will Join you In our discussions. P. G. Bonignus Market Manager Bleloctriu Fluids NEV Q0539 705075