Clinical findings among PCB-exposed capacitor manufacturing workers

Initial Medical Management of a Mini-Disaster with a Transformer Fire Emitting Polychlorinated Biphenyls

On June 22, 1982, the main power transformer at a local high school (St. Paul, Minnesota) overheated, causing the pressure relief valve to operate and release smoke and mist throughout the building. The transformer contained thermal-dielectric fluid with the tradename “Pyranol,” consisting of polychlorinated biphenyls (PCB's) in the form of “Aroclor” and chlorinated benzenes. The transformer did not explode or flame. The emmission characterized by a “white mist” occurred over an approximately 4-hour period with resultant contamination of basement and first floor areas. The temperature of the emission was estimated to be approximately 250-300°F.

“Pyranol” contains PCB aroclor 1260 (45%) and chlorinated benzenes (40% trichloro and 15% tetrachlorobenzenes). Commercial PCB preparations manufactured in the United States have been marketed under the trade name “Aroclor.” Several grades of Aroclor have been designated by numbers such as 1260. The first two digits represent the type of molecule (12 = chlorinated biphenyl). The last wo digits give the weight percent of chlorine.

The fire was discovered by the school janitor and the firefighters arrived at 5:40 a.m. As the firefighters walked near the transformer, several men began complaining of nausea, sore throat and burning of exposed skin. Firefighters having symptoms were asked to go out in the open and were immediately hosed down with water. Initially, 14 firefighters were taken to the emergency room of St. Paul-Ramsey Medical Center, where they were evaluated, treated and released. When inquiry was begun to find out what kind of substance was burning, it was discovered that the transformer which contained “Pyranol” (installed in the school in 1958) had overheated.

Chlorinated hydrocarbons in adipose tissue of infants and toddlers: inventory and studies on their association with intake of mothers' milk

Chlorinated hydrocarbon and polychlorinated biphenyl (PCB) concentrations were determined in adipose tissue from 34 infants, 14 children in the 2nd year of life, and 2 older children. The highest mean concentration detected during the first 2 years of life was for PCBs (0.67 ppm), followed by DDT (0.57 ppm), HCB (0.23 ppm), and HCH (0.15 ppm). Concentrations of HCB and PCB, which are especially characteristic of highly industrialised countries, were considerably higher in children of German mothers than in those of Turkish mothers. All single investigated values were lower than the mean values for adults in the Federal Republic of Germany, but many were still higher than mean concentrations for adults in other parts of the world. A breakdown into children with high mothers' milk intake and those with low intake showed a highly significant association with the quantity of mothers' milk consumed: the concentration of organohalogens in adipose tissue of children with high intake was significantly higher than in those with low intake. Two tasks urgently demand our attention: the development of further ways to reduce environmental sources of organohalogen contamination and the study of the possible pathogenetic effect of these organohalogens on the health of our children.

Postnatal transfer of PCBs from exposed mothers to their babies: influence of breast-feeding

Polychlorinated biphenyl (PCB) concentrations in the blood of mothers who were occupationally exposed to PCBs in a capacitor manufacturing facility, and their children, were analyzed from 1975 to 1979. The factory terminated PCB use in 1972, and environmental PCBs were eliminated artificially. Despite this, blood PCB levels of the mothers were very high, i.e., 10-100 times higher than that of non-occupationally exposed persons. In a previous report, we discussed the relationship between breast-feeding and PCB levels in the blood. This relationship is confirmed further by the present investigation which continued during a 5-yr period. The PCB levels in blood of children were influenced greatly by the duration of breast-feeding, but showed little relationship to the PCB levels in maternal blood. The PCB exposure period of the mothers, time of birth, and age of the children were less clearly related to the PCB levels in the children. The PCB concentration in the children's blood decreased at a constant rate and was independent of their blood PCB levels. A similar result was noted for their mothers' PCB levels. A slight difference, however, was found in the rate of decrease of blood PCB levels between the mothers and children. The results of questionnaire research on the health conditions and the medical examinations for the children showed that frequency of complaints, e.g., red eye, fever, itchy skin, and carious teeth, related favorably to the duration of breast-feeding. Less severe findings, i.e., decay of nails, pigmentation, mottled enamel, carious teeth, which were typical symptoms in yusho patients, were observed in some children. They were not, however, diagnosed as having PCB poisoning inasmuch as medical treatments were unnecessary.

Polychlorinated biphenyl (PCB) toxicity in adult cynomolgus monkeys (M. fascicularis): a pilot study

Aroclor 1254 and Aroclor 1248, at doses of 11.7 and 4.7 mg/kg body weight (equivalent to 5 and 2 mg/kg/day), were given 3 days per week to groups of cynomolgus monkeys, and caused weight loss, fingernail loss, facial edema, epiphora, and death. Blood and adipose tissue PCB concentrations rose with the length of treatment. Tissue concentrations in blood, adipose tissue, liver and kidneys were highest in monkeys treated with Aroclor 1254, reflecting dose differences. There was considerable variation, both within and between groups, in hematologic responses to PCB treatment. Aroclor 1254-treated monkeys had depressed and weakly responsive erythropoiesis. Aroclor 1248-treated monkeys had active but ineffective or depressed erythropoiesis with severe macrocytic or moderate normocytic anemia. Biochemical determination of blood serum constituents revealed treatment and time-related trends towards hypoalbuminemia and increased alkaline phosphatase, serum glutamic oxaloacetic transaminase, serum glutamic pyruvic transaminase, lactic dehydrogenase, cholesterol, triglycerides, total bilirubin and direct bilirubin values. Pathologic lesions common in both Aroclor groups were dilatation of meibomian glands duct; mucinous hyperplasia of the gastric mucosa; atrophy and loss of germinal centers in the splenic and other lymphoid follicles; enlargement, fatty degeneration, and necrosis of hepatocytes; bile duct and gall bladder epithelial cell hypertrophy and hyperplasia; and thyroid aberrations in follicular cell size and number of intracytoplasmic lysosomes. Lesions seen exclusively in an Aroclor 1254-treated monkey were widespread mucinous metaplasia and hyperplasia of the fundic mucosa. The results suggest that in general, cynomolgus monkeys may be more refractory or less susceptible to PCB toxicity than rhesus monkeys and, that Aroclor 1248 may be more toxic than Aroclor 1254.

Comparison of the effects of acute and subchronic administration of Aroclor 1254, a commercial mixture of polychlorinated biphenyls, on pentobarbital-induced sleep time and [14C]pentobarbital disposition in mice

We have reported previously that polychlorinated biphenyls (PCBs) alter neurochemistry and suppress spontaneous locomotor activity in mice. The present study was initiated to determine whether orally administered (Aroclor 1254) would potentiate pentobarbital-induced sleep time. Sleep time was enhanced significantly by Aroclor 1254 (500 mg/kg) given 0 to 8 h prior to pentobarbital, with the peak effect occurring at 2 h. This effect was demonstrated to be dose-responsive in the range of 5 to 25 mg/kg given 2 h prior to pentobarbital, but only slightly larger increments in sleep time were observed with higher doses of PCBs (50, 100, 250, and 500 mg/kg). Administration of vehicle or Aroclor 1254 (30 or 100 mg/kg) for 14 successive days reduced sleep time when pentobarbital was given 45 min after the last dose of vehicle or Aroclor 1254, with a further reduction when pentobarbital was given 24 h after the last dose. As a correlate to the sleep-time studies, levels of pentobarbital and metabolites were measured in brain, liver, and plasma of mice that had received varying doses of Aroclor 1254 2 h prior to [14C]pentobarbital. Elevated levels of pentobarbital and decreased levels of metabolites were found after acute administration of Aroclor 1254 during a period of time when Aroclor 1254-treated mice were still asleep. These effects of Aroclor 1254 on pentobarbital disposition were found to be dose-dependent. Brain levels of pentobarbital in mice after 14 d of Aroclor 1254 treatment (30 mg/kg) were less than those in vehicle-treated animals, and these levels were consistent with the reduced sleep times. Thus, a correlation between pentobarbital brain levels and sleep time in both Aroclor 1254-treated and nontreated animals suggests that Aroclor 1254 does not alter pentobarbital narcosis by a direct action on the brain. Rather, acutely administered Aroclor 1254 may be augmenting sleep time by competing with pentobarbital for metabolic sites in the liver, while chronically administered Aroclor 1254 induces pentobarbital metabolism.

Metabolic and health consequences of occupational exposure to polychlorinated biphenyls

In surveys of three groups of workers occupationally exposed to polychlorinated biphenyls (PCBs) serum PCB concentrations were quantitated as lower chlorinated biphenyls (L-PCBs) and higher chlorinated biphenyls (H-PCBs). Serum L-PCB and H-PCB concentrations were many times greater among workers employed in power capacitor manufacturing than exposed areas. Statistically significant positive correlations of symptoms suggestive of mucous membrane and skin irritation, of systemic malaise, and altered peripheral sensation were noted with increasing concentrations of serum PCB. No clinical abnormalities attributable to exposure to PCB were observed. Serum PCB concentrations were positively and significantly correlated with glutamic-oxalacetic transaminase (SGOT), serum gamma-glutamyl transpeptidase (GGTP), and plasma triglyceride, and inversely correlated with plasma high density lipoprotein-cholesterol. These correlations were present across all study sites. These findings are indicative of PCBs' physiological effect on the liver, whose long-range health significance is unknown. Nevertheless, the consistent positive association of serum PCB with plasma triglyceride and negative association with plasma HDL-cholesterol may have long-term cardiovascular consequences.

Dermatological findings in capacitor manufacturing workers exposed to dielectric fluids containing polychlorinated biphenyls (PCBs)

Significant occupational exposure to polychlorinated biphenyls (PCBs) may occur in the manufacturing of capacitors and transformers, in which PCBs are used as electrical insulators. Reports of adverse health effects resulting from PCB exposure have come primarily from an incident resulting from the accidental ingestion of contaminated rice oil in Japan in 1968 ("yusho"). Dermatological findings were prominent features and included pigmentation disturbances and chloracne. To evaluate the dermatological effects of long-term occupational exposure to PCBs, a cross-sectional clinical survey was conducted of 326 capacitor manufacturing workers. A high prevalence (37%) of dermatological abnormalities was found, but typical PCB-associated signs, such as chloracne, were less frequent than among patients with "yusho," despite high concentrations of plasma PCB. As association between dermatological signs and plasma levels of higher homologues of PCBs was suggested, but contaminants which have been reported to be present in commercial PCB mixtures (polychlorinated dibenzofurans) should be considered an etiologic factor or co-factor in the development of "PCB-associated" dermatological findings.

Body burden of polychlorinated biphenyls among persons employed in capacitor manufacturing

In an effort to assess exposure among workers engaged in capacitors manufacture, PCB concentration was determined in plasma (290) and adipose tissue (61). In general, males had higher concentrations of PCBs than females. The correlation of plasma concentration (1-546 ppb) of the more highly chlorinated PCBs, which had been used in past, with total duration of employment suggested accumulation over time. The gc-ec pattern of these PCB peaks was, in most cases, characteristic of exposure to a PCB mixture with 54% chlorine. The less highly chlorinated PCBs, di-, tri-, and tetrachlorobiphenyls, were the source of current exposure, and were observed in concentrations of 6-2530 ppb in plasma. Higher exposure occurred among persons with direct contact with PCBs in jobs such as capacitor filling. Adipose tissue concentrations, for both the more highly chlorinated PCBs (1-165 ppm) and lower chlorinated PCBs (0.6-414 ppm), were proportional to those in plasma.

Mortality and industrial hygiene study of workers exposed to polychlorinated biphenyls

Because of the demonstrated toxic effects on animals resulting from exposure to polychlorinated biphenyls (PCBs), the National Institute for Occupational Safety and Health conducted a retrospective cohort mortality study of 2,567 workers in two plants where PCBs were used in the manufacture of electrical capacitors. All workers included in the study were employed for at least 3 months in areas of the plants where PCBs were used. The vital status of 98% of the two cohorts was determined, and 39,018 person-years were accumulated. All-cause mortality was lower than expected (163 obs. vs 182.4 exp.) as well as all cancer mortality (39 obs. vs 43.8 exp.). Excess mortality was noted for rectal cancer (4 obs. vs 1.19 exp.) and liver cancer (3 obs. vs 1.07 exp.), although neither excess was statistically significant. In one of the plants the observed mortality due to cirrhosis of the liver was also elevated. The results of detailed industrial hygiene surveys conducted in each plant are also presented.