845 PCBs AND ASSOCIATED AROMATICS INTRODUCTION Polychlorinated biphenyls (PCBs) are a family of chemical compounds which do not exist in nature but which are man- made. Commercial mixtures are clear, pale yellow liquids manufactured by the replacement of hydrogen atoms on the biphenyl molecule by chlorine. The reaction is controlled according to the percentage replacement of hydrogen and results in a product which contain chlorobiphenyls with one or, more usually, several chlorine atoms attached to each molecule. The family of polychlorinated biphenyls can contain from 1 to 10 chlorine atoms arranged within the molecule in 209 different ways. The different molecular combina- tions are called congeners. The congeners which comprise the series of compounds with the same number of chlorine atoms are known as an homologous series. The congeners are named according to the homologous series to which they belong. For example, a PCB containing 3 chlorine atoms would be called a trichlorobiphenyl, or one with 5 chlorine atoms a pentachlorobiphenyl. The homolo- gous series of PCBs and the number of isomers contained in each are listed in Table 1. The synthesis of biphenyl and its subsequent reaction with chlorine to yield polychlorinated biphenyls is shown PCBs have been manufactured by various companies throughout the world and are often referred to by the manu- The perceptions of risk associated with ownership and operation of PCB containing equipment is related to the risk of fires, spills, cleanup or noncompliance with regulations. The following time line focuses on the development of PCB risk perceptions as new knowledge grew from the time that PCBs were first used in industrial applications. 1881 PCBs were first described in the chemical literature in 1881 by Schmidt and Schultz. 1929–1931 PCBs were developed by the Federal Phosphorus Company and Swann Research Co. The latter business was bought by Monsanto in the Early 1930’s. The available data on the toxicity of PCBs were first summarised in an article published in 1931 (Smyth, 1931). 1933 The first reported episode of PCB-related toxicity occurred in 1933, at the Swann Chemical Co. Twenty three of 24 men working on the manufacture of PCB almost simultaneously developed skin eruptions that were diagnosed as ‘chloracne’. Some of the men also complained of lassitude. The investi- gators report on the episode concluded that the toxic agent was an unidentified impurity, which had probably appeared TABLE 1 Chlorobiphenyl Empirical Formula # of Isomers Weight% Cl mono C 12 H 9 Cl 3 18.8 di C 12 H 8 Cl 2 12 31.8 tri C 12 H 7 Cl 3 24 41.3 tetra C 12 H 6 Cl 4 42 48.6 penta C 12 H 5 Cl 5 46 54.3 hexa C 12 H 4 Cl 6 42 58.9 hepta C 12 H 3 Cl 7 24 62.8 octa C 12 H 2 Cl 8 12 66.0 nona C 12 HCl 9 3 68.7 deca C 12 Cl 10 1 71.2 Adapted from Reference 1: Hutzinger et al. Ј C016_003_r03.indd 845C016_003_r03.indd 845 11/18/2005 1:12:21 PM11/18/2005 1:12:21 PM © 2006 by Taylor & Francis Group, LLC in Figure 1. facturer’s trade name. Table 2 lists the main producers. 846 PCBs AND ASSOCIATED AROMATICS in the PCB when a new source of crude benzene was used for making the biphenyl. When purchase from this benzene source was discontinued, and the process better enclosed, the chloracne problem disappeared. 1936 Halowax acne was a term first coined by Jones and Alden in 1936 to describe chloracne induced by PCBs. PCBs were being manufactured in a distillation process in which biphe- nyl was extracted from coal tar using benzene, styrene, tol- uene and xylene. Once the biphenyl was extracted, it was chlorinated with chlorine gas to produce PCB. Chloracne was identified in workers manufacturing Aroclors [Schwartz, 1936]. 1937 An early case report of death by cirrhosis of the liver with acute yellow atrophy may be attributable to PCNs rather than PCBs [Drinker et al., 1937]. 1938 Morphological changes were observed in rats dosed orally with PCBs (Aroclor 1265) in concentrations as low as 0.001 mg/Kg/d [Bennett et al., 1938]. 1943 Good and Pensky described the formation of acneiform eruptions in workers manufacturing Aroclors. An investigation of dermatitis among cable strippers in the shipbuilding industry revealed lesions, cysts and kera- tinization of skin in not only the workers, but also in some spouses and children [Schwartz, 1943]. 1944 Skin lesions similar to chloracne in humans were observed in three species of laboratory animals subcutaneously exposed to Aroclor 1242 at levels ranging from 7 mg/Kg/d to 138 mg/Kg/d [Miller, 1944]. FIGURE 1 The reaction of anhydrous chlorine with biphenyl results in isomers of homologous series of PCBs. TABLE 2 Commercial PCB mixtures have been produced worldwide Trade name Manufacturer Country Aceclor ACEC Belgium Apirolio Caffaro Italy Aroclor Monsanto United States Clophen Bayer West Germany Kaneclor Mitsubishi Japan Pyralene Prodelec France Pyranol G.E. United States Pyroclor Monsanto (U.K.) United Kingdom C016_003_r03.indd 846C016_003_r03.indd 846 11/18/2005 1:12:22 PM11/18/2005 1:12:22 PM © 2006 by Taylor & Francis Group, LLC PCBs AND ASSOCIATED AROMATICS 847 1949 PCBs extracted from air were analyzed by Jacobs (1949) before the advent of gas chromatography. 1950 In the 1950–1952 time frame, an episode of PCB poison- ing occurred when 7 of 14 people exposed to vapors from a leaking PCB-filled heat exchanger developed chloracne. [Meigs, 1954]. 1952 Askarel used in capacitors up to 1952 was Aroclor 1254. After 1952 the type of askarel was changed to Aroclor 1242. 1953 Badische Anilin had an industrial accident on 17th November, 1953 and is one of seven similar accidents which have been recorded. The process involved the manufacture of trichloro- phenol from tetrachlorobenzene (Figure 2). The Seveso incident, which occurred in 1976, is per- haps the best documented industrial accident of this type. Thermographic records at the Seveso plant showed an uncon- trolled rise in the temperature of the reaction vessel, following failure of a safety shutdown device. The mixture was heated at 230° to 240°C for 4 to 5 hours and 3 to 4 atmospheres before a safety disc ruptured and released nearly the entire mixture (Figure 3). 1954 Meigs et al. estimated that about 1 year was required to develop chloracne after the beginning of exposure to air with a concentration of 0.1 mg PCB/m 3 . PCB was used as a heat exchange fluid for a reaction chamber. There was leakage of vapour which exposed a group of 7 to 14 workers. 1956 A Monsanto accident in the manufacture of chlorophenols occurred in the Monsanto Nitro Plant during 1949. A similar accident also occurred at Badische Anilin in Germany on 17th November, 1953. Monsanto described their experience in a 1956 memo- randum with personnel from Badische Anilin: “A thorough systematic investigation has isolated impurities in the tri- chlorophenol process (or residues) which will cause the same effects in rabbits.” The materials mentioned include “pentachlor naphthalene” and “chlorinated diphenyl oxide”. PCDFs and PCDDs can be formed from chlorophenols in three different ways as follows: 1) the dimerization of chlorophenates; 2) the cyclization of polychlorinated diphenyl ethers (PCDPEs); 3) the cyclization of polychlorinated phenoxy phe- nols, termed pre-dioxins. 1 The dimerization of chlorophenates has been shown in the reaction shown above. 2 Polychlorinated diphenyl ethers are formed in the polychloro-phenol synthesis according to the fol- The formation of PCDFs from the cyclization of polychlorinated diphenyl ethers is as follows 3 Polychlorinated phenoxy phenols are termed ‘pre- dioxins’ for the reason that they are intermediates One or more of the steps in the formation of PCDDs has a high activation energy. Activation energy in chemical FIGURE 2 The intended reaction produces TCP. FIGURE 3 The dimerization of chlorophenates yields PCDDs. C016_003_r03.indd 847C016_003_r03.indd 847 11/18/2005 1:12:22 PM11/18/2005 1:12:22 PM © 2006 by Taylor & Francis Group, LLC lowing reaction (Figure 4). (Figure 5). in the cyclization sequence (Figures 6 and 7). 848 PCBs AND ASSOCIATED AROMATICS thermodynamics is a concept which describes the energy flow in a reaction from reactants to products. When there is a high activation energy barrier, the reactants require more energy to attain an activated state than when there is a low activa- tion barrier. Once the reactants have gained enough energy to form an activated intermediate they can either return to the reactant form or proceed to a stable product. The bal- ance between the forward and backward reaction directions is an equilibrium condition which may be heavily weighted in favor of either the reactants or products. The high activa- tion energy in the formation of PCDDs contributes directly to their low yields. The residue from the trichloro-phenol distillation in the Monsanto synthesis was reported to be 20 times less effective in producing liver necrosis in rabbits than the residue of the fraction remaining after heating to above 230°C. The boiling points of many dioxin precur- sors are lower than the reaction temperature range in which PCDDs are formed and therefore there is a loss of precursor molecules before reaction can occur. The possibility of pressure differences in the formation of the residues are only one of several key parameters which make the comparison difficult. It is, nevertheless, clear that the residue derived from the high temperature distillation was substantially more toxic than the pentachloro naphtha- lene studied. The health effects of PCNs had been described in the literature some 17 years before but the effect observed on rabbits left in the operating area after the BASF accident was surprising—they died from liver necrosis after a one week exposure! 1957 A review of characteristic chloracne lesions appeared in 1957 by Schwartz et al. 1962 Threshold limit values for PCBs in workroom air were set in 1962 by the American Conference of Governmental Industrial Hygienists. Under “Chlorodiphenyl—42% Chlorine” it was stated that “Acne, systemic poisoning and even death may result from exposure to chlorinated diphe- nyls.” The references indicated were [Schwartz, L.: Am. J. Pub. Health; 26, 586 (1936) and Drinker, C.K., Warren, M.F., Bennett, G.A.: J. Ind. Hyg. & Tox.; 19, 283 (1937)]. A threshold limit value of 1 mg/m 3 was recommended to offer good protection against severe systemic toxicity but may not guarantee complete freedom from chloracne. In other words, it was recognized that there was a risk of severe systemic toxicity and that chloracne was a separate issue. FIGURE 4 Formation of polychlorinated diphenyl ethers (PCDPEs) can lead to the formation of polychlorinated dibenzofurans (PCDFs). FIGURE 5 Loss of HCl produces cyclization of the diphenyl ether to a dibenzofuran. FIGURE 6 FIGURE 7 Loss of H 2 from the pre-dioxin produces PCDD. C016_003_r03.indd 848C016_003_r03.indd 848 11/18/2005 1:12:23 PM11/18/2005 1:12:23 PM © 2006 by Taylor & Francis Group, LLC PCBs AND ASSOCIATED AROMATICS 849 Chick edema disease was linked to PCB exposure when chicks were placed in galvanized cages that were coated with an epoxy resin paint. The paint had not hardened prior to placing the chicks in the cages, and within three weeks the chicks showed symptoms resembling those that had been reported as chick edema in incidents resulting from toxic components in chicken feed [McCune et al., 1962]. Chick edema disease was linked to PCB exposure when chicks were placed in galvanized cages that were coated with an epoxy resin paint. The paint had not hardened prior to placing the chicks inside the cages, and within three weeks the chicks showed symptoms resembling those that had been reported as chick edema in incidents resulting from toxic components in chicken feed [McCune et al., 1962]. Aroclor 1242 was determined to be the causative agent. Prompted by this initial finding, further studies on the effects of PCBs in chicks were conducted. Studies on chicks fed Aroclor 1242 showed high mortality, hydropericardium (accumula- tion of water in the sac that surrounds the heart), hemor- rhagic edematous lungs (abnormal swelling from blood and fluid accumulation in the lungs), kidney tubular dilation and lesions, swollen liver, and a dose-dependent pathology [McCune, 1962; Flick et al., 1965]. Growth rates of chicks were slowed in a dose-dependent manner and defeathering and dermatitis were reported [Flick et al., 1965]. 1963 A study with chick embryos showed 0% hatchability in high Aroclor 1242-dosed embryos. Embryo’s showed beak deformity, edema and growth retardation [McLaughlin et al., 1963]. 1966 In 1966 the American Conference of Governmental Industrial Hygienists amended their description of the suggested limit of “Chlorodiphenyl—42% Chlorine—Skin” and stated that “Acne is not an invariable warning sign of impending, more severe, systemic toxicity” (Figure 8). Jensen identified Aroclors 1254 and 1260 while analyzing for DDT [Jensen 1966]. He detected the presence of certain unidentified peaks in specimens of white-tailed eagle feathers dating as far back as 1942. Since DDT was used widely as a pesticide only after 1945 it was apparent that the pesticide-like chemical found in the samples was not a DDT break-down product, DDE or DDD. In 1967 G. Widmark unambiguously identified the contaminants as PCBs using MS. The initial work by Jensen (1966, 1969) and of Risebrough (1968) sparked an immediate concern that PCBs had become ubiquitous in the environment. The information was reported in the San Francisco Chronicle of February 24, 1969. In an open letter to Monsanto’s customers, the Environmental Health department, gave a cautious overview of the findings on March 3, 1969. 1967 G. Widmark published “IUPAC Commission of Methods of Pesticide Analysis: Possible Interference by PCBs.” FIGURE 8 Widespread contamination by these compounds complicated the analytical quantitation of PCBs. C016_003_r03.indd 849C016_003_r03.indd 849 11/18/2005 1:12:23 PM11/18/2005 1:12:23 PM © 2006 by Taylor & Francis Group, LLC 850 PCBs AND ASSOCIATED AROMATICS Also: Jensen, S. and G. Widmark: OECD pesticide confer- ence report on unintended residues in the environment. 1968 Risebrough et al. (1968) published in Nature: “Polychlori- nated Biphenyls in the Global Ecosystem”. Found that the eggshell thickness of fragments of a peregrine falcon egg was 34% less than the thickness of eggshells present in the same area 21 years previously. September, 1968: Information sent by Westinghouse on “Inerteen and Environmental Contamination” described that “It has been indicated by several laboratories that measurable amounts of the PCBs are present in our general environment and may have some effect on certain species of wildlife. While askarels are generally regarded as being non-toxic to humans, it is reasonable to assume that very high standards of con- trol will be issued by the Government in the overall program against pollution”. The bulletin indicated that Monsanto had arranged for return of scrap Inerteen fluid in sealed drums and indicated that “Inerteen soaked coils, insulation scrap, filter cartridges, and other materials must be stored until appropri- ate methods can be provided to dispose of them properly.” In October 1968, Japanese health officials became aware of an epidemic disease which came to be known as “Yusho”. The cause of the disease was the ingestion of PCB contaminated rice oil over a period of about eight months [Kuratsune et al., 1972]. The epidemic became the subject of a special issue of the journal Fukuoka Acta Medica in June 1969 [Kuratsune et al., 1969]. The incident is impor- tant because it clearly documents the potential for reproduc- tive and transplacental effects in humans. About 325 patients with acneiform eruptions had been treated in northern Japan between the summer of 1968 and January 1969. The apparent cause of the poisoning was traced to the consumption of a particular brand of rice bran oil. By May 1970 the total number of cases had risen to 1,291. The common symptoms included acneiform erup- tions, hyperpigmentation of the skin, nails and mucous membranes, swelling of the upper eyelids, and hyperemia of the conjunctivae. The ‘Yusho’ incident and another very similar accident in Taiwan, known as the ‘Yu-Cheng’ incident, are fully dis- cussed in a later section. The Yusho incident prompted the US Food and Drug Administration to initiate a national survey to determine the extent and levels to which PCBs might have made their way into the food chain. 1969 Analytical methods for the detection of PCBs in food became recognised as routine by the Food and Drug Administration (FDA). Kuratsune et al. (1969) published an article entitled “Study on ‘Yusho’ or Chlorobiphenyls Poisoning”. Among the women with Yusho who were pregnant at the time of the outbreak, some were examined for observations that might indicate reproductive effects upon human exposure to PCBs. Since these case reports are based upon a small sample of Yusho cases, there observations cannot be verified statistically and are therefore only indicators that PCBs in rice oil might result in some reproductive effects that are not inconsistent with those reported in laboratory studies. Out of nine pregnant women, all of whom had char- acteristic Yusho poisoning, two incidents of stillbirth were reported in which the fetuses manifested Yusho symptoms such as brown staining of skin, nails and gingive [Taki et al., 1969]. February 24, the San Francisco Chronicle carried a major feature about “a menacing new pollutant” in marine life research carried out by Dr. Robert Risebrough of the University of California. March 3, 1969: Information on the San Francisco Chronicle’s article is circulated to Monsanto customers in a letter dated March 3, 1969. On March 7, 1969 the Associate Commissioner for Science and Deputy Associate commissioner for Compliance asked the Bureau of Science to evaluate foods sampled for pesticides for evidence of PCBs. None was indicated using the analytical methods of that time except for traces of PCB in fish from the Great Lakes. March 10–14, 1969: District pesticide experts were given analytical information concerning PCB and told to be aware of the possibility of its presence in foods. (Pesticide Analytical Workshop 3/10–14/69). PCB was identified as a contaminant of many of the fish analyzed as part of proceedings against the City Smoke Fish Co. of Detroit, MI (June and July 1969). The fish also con- tained DDT above 5 ppm. July 1969: Cow’s milk was found to be contaminated with PCBs (July 1969) from cows given feed treated with herbicides that had been diluted with PCBs. On September 13, 1969 the Baltimore District Office of the FDA reported PCB in West Virginia milk. The source was traced to the use of an Aroclor as a solvent for pesticide spray. Regulatory action at 0.2 ppm PCB on a whole milk basis was established by the FDA on December 16, 1969. 1970 Aroclor 1260 was discontinued in 1970. 1254 was an avail- able alternative. Monsanto, the only producer of PCBs in the US alerted its customers to the potential problem of environmental con- tamination. Major electrical equipment manufacturers were requested to relay the information to end-use customers with advice as to proper destruction of PCBs. Monsanto advised clients from 1970 onwards to be careful not to let water that may contain PCBs get into sumps or drains that would lead into the sewer system. In 1970, the FDA prepared a summary of the available information on the chemistry and toxicity of PCBs. [US Dept. of Health, Education, and Welfare (1970): “Supplement 1— Status Report on the Chemistry and Toxicology of PCBs of C016_003_r03.indd 850C016_003_r03.indd 850 11/18/2005 1:12:23 PM11/18/2005 1:12:23 PM © 2006 by Taylor & Francis Group, LLC PCBs AND ASSOCIATED AROMATICS 851 Aroclors”; Washington, D.C.: Bureau of Foods, Food and Drug Administration, Public Health Service.] During 1970, the Council on Environmental Quality (CEQ) studied regulatory approaches to the problem of toxic chemicals in the environment. In its report published in 1971, CEQ iden- tified PCBs as a major problem. [Council on Environmental Quality (1971): “Toxic Substances”; Washington, DC.] Vos et al. (1970) published “Identification and Toxicolo- gical Evaluation of Chlorinated Dibenzofuran and Chlorinated Naphthalene in Two Commercial PCBs”. Increased levels of porphyrins are consistent with chronic hepatic porphyria that has been associated with exposures to other polyhalogenated aromatics. This condition can range from a subclinical state, where increased urinary porphy- rin excretion results in no observed adverse effects, to por- phyria cutanea tarda (PCT) which is a skin disease resulting in excessive light sensitivity, scaling, and itching. Increased levels of coproporphyrins and protoporphyrins in faeces and porphyrins in liver, bile and the small intestines of chicks fed Aroclor 1260, Clophen A60 and Phenoclor DP6 were reported by Vos and Koeman (1970). Morphological changes in monkeys were observed with doses ranging from 1.4 mg/Kg/d to 16.4 mg/K/d and also mice dosed with 12.8 mg/Kg/d [Nishizumi, 1970]. Aroclors 1221, 1232, 1242 and 1248 in high doses, bind to estrogen receptors in the rabbit uterus [Bitman and Cecil, 1970]. Close parallels between the toxic effects of PCBs and PCDFs/PCDDs were established in a series of studies and reported in major scientific reviews such as [Crow, 1970]. Cleanup methods for analysis were devised to separate DDT and its analogues from some of the PCBs [Amour and Burke, 1970]. The Pesticide Regulation Division of the FDA issued PR Notice 70–25 instructing manufacturers and formulators of economic poisons containing PCBs and PCTs to change their formulations to exclude these classes of compounds. Open letter from GE Electric Utility Sales Division to electric utility customers expresses environmental concerns and starts “As you are well aware the public concern with pollution is rapidly escalating.” February 3, 1970: The FDA initiated a regulatory thresh- old value of 5 ppm PCB in the edible flesh of fish, February 3, 1970. August 1970: Fish near the effluent of Monsanto’s Annison plant were found to contain PCB in August 1970. August 1970: Cow’s milk was found to be contaminated with PCBs (August 1970) from cows given feed that had been stocked in silos coated with PCB-based products. September 1970: The Office and Science and Technology panel on Hazardous Trace Substances reviewed cadmium, arsenic and PCBs. Also, the National Swedish Environment Protection Board held a conference on PCBs. One of the sessions of the conference highlighted “environmental prob- lems”. This conference, perhaps for the first time, brought together the extent of understanding of the manufacture, use, extent of environmental contamination, analytical methods, and biological effects of PCBs. September 14, 1970: An open letter from Monsanto, dated September 14, 1970 states: “As a supplier of askarel fluids namely Inerteen, Pyranol, and Aroclors which do con- tain PCBs, we wish to inform you that the FDA announced a guideline for PCB of 5 ppm in fish and 0.2 ppm in milk. Therefore, control of waste and spills is imperative.” A letter was sent to Monsanto customers requesting information on the quantities of PCB fluids that might be shipped to Monsanto for disposal so that the company could design an appropriate sized incinerator. October, 1970: At the October Double Client Committee meetings, a subcommittee was formed to investigate PCB disposal problems. October 12–14, 1970: The International Electrotechnical Commission Technical Committee No. 10; Liquid and Gaseous Dielectrics Subcommittee 10B; Insulating Liquids Other than Hydrocarbon Oils indicated in its minutes of meeting dated October 12–14, 1970: “Agenda–Item 5—To review current concern with the finding of PCBs in some environments and what action should be taken in recom- mending precautions in the application, processing and effluent disposal of askarels to prevent them becoming envi- ronmental contaminations . Copies of IEEE and ASTM documents were circulated by the US Delegation. A French Delegate circulated copies of a publication from Prodelac (a French producer of askarels).” October 28, 1970: Minutes of the IEEE Insulating Fluids Subcommittee dated October 28, 1970 indicated “Monsanto will, however, discontinue by the end of 1970, the sale of Aroclors for application as plasticizers, heat transfer agents, hydraulic fluids and other non-electrical applications.” November 19, 1970: A NEMA letter to (ANSI) dated November 19, 1970, regarding the proposed committee on the disposal of askarel used in electrical equipment indicates “ . The Monsanto Company has already taken steps to limit the availability of askarel to those users where the fluid is essential and is contained in a closed system, such as is the case for transformers and capacitors. With the coopera- tion of transformer and capacitor manufacturers, steps have been taken to alert all known users on the problem and on corrective measures. Monsanto has also instituted a means for disposing of askarel-soaked waste materials, coils, insu- lation, scrap, discarded capacitors, etc.” November 1970: Occurrence of PCBs in chickens fol- lowing absorption from PCB-containing plastic wrappings. In December 1970, Monsanto sent a letter to end users of PCB products requesting information on the amount and types of solid PCB contaminated materials that might be shipped to Monsanto for disposal. Monsanto was in the pro- cess of sizing the design for a kiln to incinerate PCB wastes and intended to make the service generally available. 1971 In 1971 Monsanto began to phase out production of the more highly chlorinated Aroclors: 1232, 1248, 1260, 1262 and 1268. C016_003_r03.indd 851C016_003_r03.indd 851 11/18/2005 1:12:24 PM11/18/2005 1:12:24 PM © 2006 by Taylor & Francis Group, LLC 852 PCBs AND ASSOCIATED AROMATICS In 1971 Monsanto introduced Aroclor 1016, which had an average chlorination similar to Aroclor 1242 but with fewer of the more highly chlorinated compounds. At the end of 1975, only Aroclors 1221, 1016, 1242 and 1254 were still being produced. Up to this point in time (1971) the principal government “control” actions for PCBs were the result of ‘persuasion’ by the Federal Government rather than by direct regula- tory exercise. The Government possessed no real regulatory authority to control the manufacture, distribution or use of PCBs. However, strong influence was brought to bear by the several Government inquiries of the time—especially the PCB Interdepartmental Task Force. The principal recom- mendation of the PCB Task Force was the discontinuance of all uses of PCBs except in electrical capacitors and trans- formers. The latter uses were judged to be both essential to industry and represented ‘closed’ systems. Thus, the major action of PCB manufacturing phaseout and use restrictions were taken ‘voluntarily’ by Monsanto. An OECD study on the sampling and analysis of residues in wildlife involved 23 laboratories in 13 OECD member countries between 1966 and 1971 and confirmed that residues of organochlorine pesticides, PCBs and mercury were to be found in a wide variety of species, in different habitats, and in areas where PCBs have not been deliberately released. The OECD published a case study report of PCB and mercury pollution in Japan in 1976. The general situa- tion regarding PCB pollution was described as follows: “Environmental pollution of PCBs was first recognized in Europe followed by the US then Japan. Results of field investigations demonstrated that PCB pollution in organ- isms inhabiting the natural environment was at a severe level. In Japan, analytical results indicating concentrations of residues in wild animals were first reported in 1971. In January of 1972, a standard method for the analysis of PCBs was established by the research group of the Ministry of Health and Welfare sponsored by Science and Technology Agency, whereby the uniform analysis of PCB residues in wild animals was realized A national survey concerning environmental pollution of PCBs was conducted from May to December, 1972. During this period, the water quality of 1,084 locations and bottom sediments sampled from 1,445 places was inspected.” During 1970, the Council on Environmental Quality (CEQ) studied regulatory approaches to the problem of toxic chemicals in the environment. In its report “Toxic Chemicals” published in 1971, CEQ identified PCBs as a major problem. [Council on Environmental Quality, 1971]. The instructions for handling Westinghouse’s Inerteen insulating fluid referenced the ANSI C107.1–1974 for com- plete information on handling and disposal of Askarels. The document also included a section on “Environmental Considerations” which stated “It has been shown by several laboratories that measurable amounts of the PCBs, particu- larly those with more than 50% chlorination, are present in the general environment and are a threat to certain species of wild-life. . To be sure that the Inerteen and Inerteen contaminated materials do not contaminate the environment they must be incinerated in approved equipment.” A disposal section in the handling instructions describes the disposal of Inerteen liquid, solvent rinses contaminated with Inerteen, solids contaminated with inerteen and the cleaning of con- taminated drums. The American Conference of Governmental Industrial Hygienists retained a threshold limit value of 1 mg/m 3 in 1971 and stated “Exposure to the vapor and fume of chlorodi- phenyl may result in acne, irritation of respiratory passages, and injury to the liver . . Several deaths due to atrophy of the liver occurred among workers exposed to the fumes of chlorodiphenyls and chloronaphthalenes.” Transplacental passage of Aroclors 1221 and 1254 in rabbits was observed [Grant et al., 1971] when PCB resi- dues were found in higher concentrations in fetal liver than in tissues of dosed does. Placental and adipose tissues of stillbirths from Yusho mothers confirmed the presence of Kanechlor components [Kuratsune et al., 1971]. The total quantity of contaminated rice oil ingested by patients in the Yusho incident of 1968, as well as the dose rate of ingestion of PCBs was estimated 38 by Yoshimura, 1971. Studies of Yusho patients have revealed symptoms of numbness, pain, hypothesia or areflexia of the limbs in about 50% of cases [Murai and Kuroiwa, 1971]. From 1971 to December 1975 a frequent method of dis- posal of askarel capacitors was to throw them into a dumpster for disposal in various landfills. The State of Massachusetts enacted a bill in 1971 to prohibit the discharge of any chemical solution containing PCBs into the environment. A paper was presented at the 1971 Doble Client Conference to report activities of the special Doble subcom- mittee on askarel disposal problems. February 23, 1971: ANSI meeting of the committee on Use and Disposal of Askarel of the Power Equipment Division, February 23, 1971. “The committee noted that the purpose of this meeting is to review developments since the August 20, 1970 meeting and develop recommendations to ANSI on a suggested program of action, including priorities for various activities, list of organizations to be invited to participate, etc. The formation of the ANSI committee had as its objectives to: “1) Serve as a source of technical information and advice for Federal, State and local authorities and for the information of all others concerned. 2) Encourage the development of suitable disposal facilities and maintain a list of their capabilities and locations, for the information of all concerned. 3) Serve as the advisory group for US participation in CEE, IEC, COPANT, SEGRA and other inter- national organizations.” Between February and October 1971 TCP/PCDD/PCB was sprayed on a horse arena in Missouri. Still bottom resi- dues from TCP manufacture were contained in the waste C016_003_r03.indd 852C016_003_r03.indd 852 11/18/2005 1:12:24 PM11/18/2005 1:12:24 PM © 2006 by Taylor & Francis Group, LLC PCBs AND ASSOCIATED AROMATICS 853 oil used to control dust in Missouri horse arenas. When the waste oil storage tank was examined, it was found to contain 300 ppm TCDD. July 1971: A Monsanto PCB bulletin [Monsanto, 1971] was issued in July 1971 entitled ‘Handling, Waste Control and Disposal of PCBs’. The document was “ Produced and distributed as a service to industry by Monsanto ” . It was pointed out that Pydraul ® , a fire resistant hydraulic fluid, was no longer manufactured with PCBs but other products had a place in continued applications provided that common sense and good maintenance procedure were used towards elimi- nating any threat to the environment from PCBs. Monsanto offered nine guidelines to prevent the escape of PCBs into the environment. In conclusion, the disposal of solids was suggested in a properly operated landfill not located near any water system. The Monsanto position was explained in a series of points which included Monsanto’s recommendation that PCB contaminated solids could be buried as a satisfac- tory disposal option provided that the site was dry. Tests by Monsanto and others of PCBs in the environment had shown that the higher chlorinated PCB congeners were being retained in organisms and that there was an absence of PCBs with three chlorines or less. Some initial successes had been obtained using biodegradation of PCBs under lab conditions. The apparent lack of lower chlorinated species in the environment led Monsanto to develop Aroclor 1016 as a more environmentally acceptable product. By this time, Monsanto had made it known that it would supply Aroclors only to the electrical industry since the electrical applica- tions were considered to be enclosed. Information was pre- sented which suggested that the health effects of PCBs were minimal. Interestingly, the health effects observed in the Yusho incident were thought to have been caused by PCDFs as impurities which were typically found ‘in some European PCBs’. The correlation between PCBs and PCDFs had been shown by Vos et al. (1970) who found that the relative con- centrations of the PCDF isomers present in Yusho oil and in two samples of used heat exchanger PCBs (Kanechlor 400 and Mitsubishi-Monsanto T1248) were strikingly similar. The mechanism for the interconversion of PCBs into PCDFs was not published until 1979 [Buser and Rappe, 1979]. By 1971 Monsanto had determined that about 75% of the PCBs in the environment could be attributed to plasticiz- ers, lubricants, hydraulic fluids, incineration of PCB mate- rials and open dumps with the remainder coming from the electrical industry. It was concluded that there was sufficient biological evidence to indicate that PCBs can be deleterious to the health of animal and human life and that, even though it could not be expressed quantitatively, it was inappropriate for electrical equipment manufacturers to ignore the weight of the evidence against PCBs. Electrical equipment manufacturers were to inform customers about the nature of PCBs, and the hazards asso- ciated with them. Instructions were to be provided on the proper disposal of units containing PCBs. PCB manage- ment controls were to be initiated in manufacturing facili- ties. Customers were to be informed that the disposal of PCB liquid waste should be done by sending the material to Monsanto for incineration while failed or non-serviceable units should be sent back to the manufacturer so that the PCB in the unit could be disposed of adequately. All of the maintenance and repair shops were to be alerted concern- ing the nature of PCBs and, again, a procedure set up for the proper use and disposal of the liquid and solid waste. Equipment manufacturers intended to encourage NEMA and other industrial organizations to establish uniform use, handling and disposal standards. Field records of PCB equipment performance were to be obtained. June 1971: The National Industrial Pollution Control Council published “The Use and Disposal of electrical Insulating Liquids” in June 1971 and included in their report recommendations to minimize the possibility of entry into the environment of PCBs used in capacitors and transform- ers. These regulations were later developed by a committee of ANSI. In July 1971, leakage of a heat exchanger fluid caused contamination of pasteurized fish meal which in turn was fed as a ration to chickens and catfish. In July 1971: discovery of PCBs in food wrappings due to recycling of copy paper in the production of paper pulp. Occurrence of PCBs in turkey and chicken fed PCB- containing products (reason unknown). FDA began recall of 50 tons of meat, 300 tons of fish feed, and 3,300 tons of fish meal contaminated with PCBs caused by a leak in a heat exchanger system. In August 1971, Westinghouse’s Power Transformer Division issued an updated set of ‘Instructions for Handling Inerteen® Insulating Fluid P.D.S. 54201 CM and Installation and Maintenance of Inerteen Transformers.’ [Westinghouse, 1971], which incorporated the earlier supplemental notice of environmental concerns and waste disposal. In this version of the guide disposal suggestions are much more explicit and contain recommendations for Inerteen liquid, solvent- rinses contaminated with Inerteen and solids, including drums, contaminated with Inerteen. Environmental concerns were also expressed to the equipment purchaser much more explicitly in this document than in the earlier 1968 version: “ a carefully planned program of waste disposal must be followed at every step of the equipment life. This includes manufacture, repair and final disposition of the fluid and the Inerteen contaminated parts. ” On August 3, 1971, FDA called an Interagency meeting of spokesmen from several Federal agencies and research laboratories to review PCBs. OST released its report on PCB environmental impact in March 1972. September 1971, Monsanto introduced Aroclor 1016 as a replacement for Aroclor 1242 in capacitors. The fluid was made by vacuum distillation of Aroclor 1242 to remove the more highly chlorinated PCB homologs since these were recognized as being less biodegradable than the lower chlo- rinated congeners. September 1, 1971 representatives of several Agencies of the Federal Government established an Interdepartmental Task Force to coordinate the scientific efforts relative to understanding PCBs. The Agencies involved were USDA, C016_003_r03.indd 853C016_003_r03.indd 853 11/18/2005 1:12:24 PM11/18/2005 1:12:24 PM © 2006 by Taylor & Francis Group, LLC 854 PCBs AND ASSOCIATED AROMATICS EPA, the Council on Environmental Quality and the Office of Science and Technology. The OST took the lead role and the work was conducted under what became known as the Interdepartmental Task Force on PCBs. The Task Force was announced on September 5, 1971 in a joint FDA–USDA press conference. September 15, 1971: The OST Panel on Hazardous Trace Substances and the Governmental Task Force met jointly with representatives of the Monsanto Co. The principal agenda item of this meeting was a request for information concerning the amounts and usage, and estimates of losses into the environment. October 1, 1971: Norway enacted regulations which came into effect on October 1, 1971 which required prior authorization for the use of PCBs. December 1971: Monsanto adopted a policy not to sell any more dielectric fluids to its customers before they entered into an indemnity agreement. December 20–21, 1971: National Institute of Envir- onmental Health Sciences symposium on PCBs held at Durham, NC on December 20–21, 1971. Members of the press, especially science writers, were invited to attend. Thus, the aims of the conference were to educate both scientists and the public about the science of PCBs and its interpretation. 1972 PCBs were the subject of an increasing number of papers reported in the scientific literature dealing with the environ- ment between 1970 and 1971. A conference which dealt with the environmental problem of PCBs was held in September 1970 in Sweden and in August 1971, an environmental qual- ity workshop was convened in Durham, New Hampshire by the National Academy of Sciences. The lay press, prompted by the newsworthiness of several accidental PCB spills and the widespread finding of PCBs in the environment, published many articles in 1970–1971 which dealt with PCB contamination. Many PCB reports involved the contamination of foodstuffs. The Federal Department of Agriculture made an exten- sive surveillance of food in cooperation with the Department of Agriculture and established ‘Action Levels’ for PCBs in milk, poultry and fish. Action levels are temporary thresh- olds for regulatory decision pending the establishment of regulatory policy and procedure. During 1970 and 1971, the FDA used these guideline values in several seizures of foods found to be contaminated with PCBs. Following announcements in the public press in 1971 there began to be political enquiries made by Senator By August 1971, the FDA was being pressured into taking a position in which public pressure and advocacy demanded a stronger position against the use of PCBs. FDA initiated a meeting to discuss the scientific issues concern- ing PCBs which involved several Government agencies and Federal research laboratories. Following this meeting the FDA asked the President’s Science Advisor to provide a focus for the Government’s actions and decisions concern- ing PCBs. The request was made because: • the PCB issue cut across several Federal agencies; • the issue was becoming politically stressful for the FDA; • the Office of Science and Technology (OST) had already started a scientific review of PCBs (October 1970). The OST review committee became known as the Panel on Hazardous Trade Substances and had as its goal the identi- fication of the needs for information by the Government in making judgments concerning trace hazardous substances. On September 1, 1971 the FDA met with the USDA, EPA, the Council on Environmental Quality (CEQ) and the OST to explore options concerning PCBs. The OST adopted the lead role and this group became known as the Interdepartmental Task Force on PCBs. The Task Force met with Monsanto, the only US producer of PCBs to request information concerning the amounts of PCBs produced, pat- terns of distribution and usage, and estimates of losses into the environment. A model was developed for the rates and routes of envi- ronmental transport of PCBs based on Monsanto’s informa- tion. The model coefficients were tested wherever possible by physical measurement and analytical monitoring. The exercise pointed up gaps in the knowledge base. In particu- lar, analytical methods for PCBs were not well developed and biological effects were not well defined. The final Interdepartmental Task Force report, in addi- tion to being a review of the scientific information of the time also dealt with the benefits of PCBs derived from a National Bureau of Standards (NBS) report. This review became the basis for the rule-making decision to maintain electrical uses of PCBs and to restrict other applications. The Task Force report reviewed the Federal regulations for their applicability to PCBs in part to determine the power of the Government to control and limit the manufacture, dis- tribution, use and disposal of PCBs. Regulatory authorities were capable of responding to specific incidents of contami- nation but the Government had no power to prevent more PCBs from entering the environment. Despite mounting public pressure calling for an outright ban on PCBs the Commissioner of the FDA held a press conference in which he deferred the decision making pro- cess until further review and deliberation of perspectives had been accomplished. During this time period, the National Institute of Environmental Health Sciences had initiated its own review of scientific knowledge concerning PCBs and it brought together the scientific community and the public in a confer- ence to discuss the findings in December 1971. The result of the information exchange was to reduce the sensationalism surrounding PCBs and to reduce the newsworthiness of the now more scientific issues. The result was that a dramatic decline occurred in the number of sensational newspaper reports concerning PCBs. C016_003_r03.indd 854C016_003_r03.indd 854 11/18/2005 1:12:24 PM11/18/2005 1:12:24 PM © 2006 by Taylor & Francis Group, LLC McGovern and Governor Miliken of Michigan (Figure 9). [...]... number of broad aspects of the PCB question Most important, perhaps, was the exploration of the benefits or utility of PCBs and of the industrial and commercial dependencies built up over the years This explicit review of benefits of PCBs was of vital important for decision-making on PCBs The National Bureau of Standards engaged in a review and analysis of the benefits and even the “essentiality” of each... Class I and Class II compounds are the coplanar and mono-ortho-coplanar PCBs, respectively Class III are mono-ortho-coplanars, which lack a chlorine in a paraposition Class IV PCBs are the di-ortho-coplanar compounds Classes I to IV are dioxin-like in decreasing order of potency Class V and Class VI are the tri- and tetraortho -PCBs which are not coplanar and do not elicit significant dioxin-like activity... was that of limited restriction of PCBs This was a direct outcome of the analysis performed by the National Bureau of Standards of the utility and essentiality of PCBs © 2006 by Taylor & Francis Group, LLC C016_003_r03.indd 856 11/18/2005 1:12:25 PM PCBs AND ASSOCIATED AROMATICS 857 TABLE 3 ANSI committee C 0-1 07 membership # of Representatives Organization Represented 2 Department of the Army 2 Environmental. .. failure of the equipment in a time which would be too short to allow the formation of PCDFs An EPRI report on the degradation of PCBs under electrical discharge has shown that PCDFs are not formed.46 The PCB components of Yusho oils were primarily tetra- and pentaCBs with lesser quantities of tri-, hexa- and heptaCBs and small quantities of octa- and nonCBs In contrast to the predominance of tetra- and. .. heat, moisture and electrical degradation The properties of PCBs which are the most important from the point of view of usage and environmental exposure risk are as follows: • PROPERTIES OF PCBs • • • The more chlorine used in the manufacture of PCBs the greater the viscosity of the product and the greater its • • PCBs are heat stable and have no flash or fire point; very chemically stable and unreactive;... blood, liver and adipose tissue of Yusho patients has been found to be similar to that of PCBs although the rate of elimination of PCQs appears to be similar to, or even a little faster than that of PCBs. 48 © 2006 by Taylor & Francis Group, LLC C016_003_r03.indd 879 11/18/2005 1:12:32 PM 880 PCBs AND ASSOCIATED AROMATICS TABLE 18 The relative ratios of toxic contaminants in Yusho and Yu-Cheng oils are... Safety and Health, November 3, 1975 to inform the occupational health community of the then current knowledge concerning industrial uses and the toxicity of PCBs The document contains an extensive bibliography of early literature The report states that “Prior to the environmental concern surrounding the persistence and ubiquitousness of PCBs, [Interagency Task force on PCBs: PCBs and the Environment COM-7210419,... partial oxidation and consequently, the overall toxicity of the fluid was the combined effect of compounds of concern In 1970 Vos et al.12 showed a correlation between the toxic effects of European PCBs and the concentration levels of PCDFs The relative concentrations of the PCDF isomers present in Yusho oil and in two samples of other used heat exchanger PCBs (Kanechlor KC400 and Mitsubishi-Monsanto T1248)... etc.), the large amounts of PCBs already contained in land disposal sites present a severe hazard for the future.” “Monsanto and portions of the electrical equipment industry which use PCBs have greatly reduced PCB releases to water and land over the past few years, primarily through improvement of plant housekeeping, improved waste collection and handling, and disposal of liquid wastes through... leakage and a higher proportion of leaked fluid is expected to volatilize from heat transfer systems September 1, 1983: Report on “Carcinogenic Risk Assessments of PCBs ; Health and Environmental Review Division of Office of Toxic Substances; September 1, 1983: document summarizes the results of four previous risk assessments for cancer conducted by FDA, OTA, CAG/EPA, and OTS October 1983: The Office of . & Francis Group, LLC 854 PCBs AND ASSOCIATED AROMATICS EPA, the Council on Environmental Quality and the Office of Science and Technology. The OST took the lead role and the work was conducted. or utility of PCBs and of the industrial and commercial dependencies built up over the years. This explicit review of benefits of PCBs was of vital important for decision-making on PCBs. The. decision-making on PCBs. The National Bureau of Standards engaged in a review and analysis of the benefits and even the “essential- ity” of each of the several uses of PCBs. In this, the NBS received advice