The development and prognosis of chronic intoxication by tetrachlordibenzo-p-dioxin in men

Chloracne caused by ingestion of olive oil contaminated with PCDDs and PCDFs

1. All members of a Spanish family (father, mother and six children) developed chloracne. 2. The causative agent was found to be the family's stock of olive oil, which had become contaminated with polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), pentachlorophenol, and hexachlorobenzene. 3. The more highly chlorinated PCDDs, in particular octachlorodibenzo-p-dioxin, were the predominant congeners in the oil. 4. Three members of the family exhibited either an overt or a sub-clinical disturbance of kidney function. The father also had a chronic respiratory problem. These changes could not be unequivocally attributed to the PCDDs. 5. Experimental toxicity of the oil was limited to the development of an hepatic porphyria in mice. 6. A serum sample, taken 5 years after consumption of the oil ceased, contained high levels of the PCDDs and PCDFs. Extrapolation back to ingested dose was used to validate dosage estimates. 7. The use of toxicity equivalence factors (TEFs) provided estimates of cumulative dosage to produce chloracne as 0.13-0.31 micrograms 2378-TCDD kg-1 (using EPA TEFs) or 6.7-16 micrograms 2378-TCDD kg-1 (using Nordic/NATO TEFs). 8. This is the first incident in which human toxicity is related primarily to ingestion of PCDDs and for which estimates of dosage can be made.

A cohort mortality study of forestry workers exposed to phenoxy acid herbicides

A cohort mortality study was undertaken of forestry workers at a public electrical utility who had worked for six months or more during 1950-82 and who were routinely exposed to herbicides including phenoxy acids. A total of 1222 men with 25 274 years at risk experienced 80 deaths. Ascertainment of vital state at the end of follow up was 95.5%. The male population of the province (Ontario) was used as the reference group. Overall, no excess mortality was found in this cohort relative to the reference population. A statistically significant increase in deaths occurred, however, due to suicide (SMR = 210, 95% confidence interval, 95% CI 105-376) for the cohort as a whole. No deaths were seen due to cancers such as soft tissue sarcoma and non-Hodgkin's lymphoma that have been cited by other authors as being associated with exposure to phenoxy acid herbicides. Although the cohort is not large, the absence of deaths due to these cancers is consistent with findings from other studies with sufficient numbers to allow examination of specific risks. The cohort is still young, however, and at the end of follow up most had not reached an age when increased incidence of cancer would normally be expected.

Thirty-four-year mortality follow-up of BASF employees exposed to 2,3,7,8-TCDD after the 1953 accident

2,3,7,8-Tetrachlorodibenzodioxin (TCDD) was formed in an uncontrolled decomposition reaction at BASF Aktiengesellschaft on 17 November 1953. This report presents the findings of a 34-year mortality follow-up study of 247 workers who were partly heavily exposed; 78 thereof had died. We divided these employees into three cohorts based on the amount and reliability of the exposure information. The mortality was compared with the national mortality rates in the Federal Republic of Germany (FRG) and is presented in terms of standardized mortality ratios (SMRs) together with 90% confidence intervals (CI) for different periods of time since the first exposure. In general, the overall mortality of these workers was similar to the rates of the national population. The SMR for all malignant neoplasms based on 23 deaths was 117 (90% CI: 80, 166), suggesting no overall increase in cancer among those employees. When workers with chloracne were examined separately, the SMR for all malignant neoplasms was not significantly elevated overall (SMR 139; 87, 211), but it was for the time period 20 or more years after the first exposure (SMR 201; 122, 315). Results for 22 causes of death as well as additional information on the type of exposure and skin findings are presented and discussed in relation to the current literature. In general, our results do not appear to support a strong association between cancer mortality and TCDD, but they do suggest that some hazard may have been produced.

Health effects three years after potential exposure to the toxic contaminants of an electrical transformer fire

A medical surveillance program has been established for 482 persons who were potentially exposed to polychlorinated biphenyls (PCBs), dibenzo-p-dioxins, and dibenzofurans from an electrical transformer fire in a Binghamton, NY office building in 1981. Vital Record and Cancer Registry data, medical records, and mail questionnaires were used to assess mortality, symptomatology, cancer incidence, and reproductive events through 1984. The numbers of deaths, cancers, fetal deaths, and infants with low birth weight or congenital malformations were similar to those expected on the basis of age- and sex-specific rates for upstate New York and other comparison populations. Two suicides were observed compared with 0.31 expected, but the difference was not statistically significant. After adjustment for possible confounders, persons with the greatest degree of potential exposure were significantly more likely than those with less exposure to report unexplained weight loss (relative risk [RR] = 12.80), muscle pain (RR = 5.07), frequent coughing (RR = 4.14), skin color changes (RR = 3.49), and nervousness or sleep problems (RR = 3.19). The possibility of recall bias and the intervening effects of stress, however, weaken the conclusion that toxic chemicals caused the symptomatology. Exposure-related systemic disorders, e.g., chloracne or peripheral neuropathy, were not diagnosed by personal physicians; however, some persons refused to release their medical records because of ongoing litigation. The findings are consistent with those of our earlier assessment.

Polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans: the risks to human health. A review

1 PCDDs and PCDFs are ubiquitous and persistent in the environment. They are to be found in body tissues of both humans and animals. 2 The most extensively studied PCDD is 2,3,7,8-TCDD. It has been shown to produce a wide range of effects and is considered to be a (non-genotoxic) carcinogen in animals. 3 Studies into the mechanisms of toxicity so far reveal that there is involvement of a specific receptor (Ah), however further work is required to elucidate the mechanisms of the various effects. 4 Reports on a number of human exposures to PCDDs and PCDFs are described. Results from human epidemiological studies are difficult to interpret: there have been problems in methodology; there has been inadequate information on intake, and exposures have often been to mixtures of PCDDs and/or PCDFs together with other related compounds. 5 Many regulatory authorities faced with the problem of providing an index of risk from exposure to mixtures of PCDDs and PCDFs have employed the concept of 'TCDD equivalents'. 6 Whether or not PCDDs and PCDFs pose a significant human health risk at current levels of exposure they remain of considerable interest to the toxicologist.

Rabbit serum hypertriglyceridemia after administration of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)

TCDD (2,3,7,8-tetrachlorodibenzo-p-dioxin) caused a dose-dependent decrease of adipose tissue lipoprotein lipase (LPL) activity and caused a concomitant increase in serum triglyceride concentration in the rabbit 10 d after single ip administration of either 1 or 50 micrograms/kg. Hepatic low-density lipoprotein (LDL) binding was markedly depressed and serum cholesterol concentrations were modestly increased relative to pair-fed control animals. Serum glucose concentrations were significantly lower in the rabbit administered TCDD compared to ad libitum or pair-fed control animals, although little change was observed in serum insulin concentration. Electron microscopic examination of aortic arches 20 d after a single ip administration of 50 micrograms TCDD/kg revealed ruffling, denudation, and sloughing off of the cell surface and the appearance of macrophage-like structures in the intima and media of the endothelial cells. These alterations resemble preatherosclerotic lesions typical in animals with hyperlipidemia. It is proposed that TCDD causes hyperlipidemia in the rabbit through suppression of LPL activity and LDL receptor binding.

Immunological abnormalities 17 years after accidental exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin

Eighteen workers were reviewed 17 years after accidental exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (dioxin). Clinical assessment showed that they were in good health. A study of several biochemical and immunological parameters in these subjects and in 15 carefully matched controls showed no difference in serum concentrations of hepatic enzymes between exposed workers and controls. Although mean serum concentrations of cholesterol and triglyceride were higher in exposed subjects than in controls, the results did not reach statistical significance. Antinuclear antibodies and immune complexes were detected significantly more frequently in the peripheral blood of workers exposed to dioxin. There was no significant difference between exposed workers and controls in the number of T lymphocytes, B lymphocytes, and helper and suppressor T cell counts in peripheral blood, but the number of natural killer cells identified by the monoclonal antibody Leu-7 was significantly higher in workers exposed to dioxin.

Dystonia and tremor following exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin

Forty-seven railroad workers who were exposed to polychlorinated phenols, including dioxin (TCDD), during 1979 while cleaning up the chemical spillage following damage to a tank car filled with these chemicals were followed medically for the subsequent 6 years. Two committed suicide. The initial neurological complaints included a sense of fatigue and muscle aching, both of which have been reported in other individuals following dioxin exposure. On detailed neurological examination in December, 1985, 24 of 45 had dystonic writer's cramp and/or other action dystonias of the hands. None of the involved individuals had a family history of dystonia, and all 24 dated the onset of the dystonia to the first 2 to 3 years subsequent to their toxic exposure. The dystonias varied in severity but were usually mild. No other types of dystonic involvement were recognized. Thirty-five of the 45 individuals also manifested postural and terminal intention tremor which resembled benign essential tremor. None of the involved individuals had a family history of tremor, and all 35 of those affected dated the onset of the tremor to some time subsequent to their toxic exposure. Forty-three of 45 patients had histories and findings suggestive of peripheral neuropathy. This is the first report relating any type of dystonia to prior dioxin exposure and the first report relating action dystonia, such as dystonic writer's cramp, and postural/terminal intention tremor, to toxic exposure of any type.

Assessing the health effects of potential exposure to PCBs, dioxins, and furans from electrical transformer fires: the Binghamton State Office Building medical surveillance program

A medical surveillance program has been established for 482 persons who were potentially exposed to polychlorinated biphenyls (PCBs), dibenzo-p-dioxins, and dibenzofurans from an electrical transformer fire in a Binghamton, NY office building in 1981. Blood samples were analyzed for serum concentrations of PCBs and for biochemical and hematologic parameters at the time of the fire and 9 to 12 mo later. Firefighters and individuals who were in the building for 25 hr or more were also asked about post-fire symptomatology and examined after 1 yr for disorders of the skin, eyes, liver, and neurologic system. The results indicated that reported exposure was positively related to mean serum PCB levels (p = .004). The means and individual values, however, were within the range reported by other studies of persons with no unusual exposures. Significant correlations were observed between serum PCB concentrations and levels of liver enzymes and lipids, but mean levels of these biochemical parameters were not associated with reported exposure after adjustment for relevant covariables. Approximately one-half of those examined had skin lesions, but no cases of chloracne were detected, and there was no clinical evidence of any other exposure-related systemic disorder. The data suggest that exposure to contaminants from the building did not result in substantial absorption or cause any major short-term health effects.

Estimation of exposure to Agent Orange and other defoliants among American troops in Vietnam: a methodological approach

Two pivotal problems in determining whether exposure to herbicides has caused disease in Vietnam veterans or their offspring are definition of which troops were exposed and extent of exposure. The DoD HERBS tape is the most complete publicly available record of herbicide spraying in Vietnam. It contains about 17,000 records consisting of coordinates of spray missions, dates, chemical agent, quantity and area sprayed, and mission purpose. We have developed a set of discrete and continuous indexes of probability of exposure to herbicides for individual veterans. These probability indexes are based on HERBS tape spray data and on locations and dates of service derived from a place-and-date matrix completed by the veteran. They can take into account a conservative estimate of environmental persistence of herbicide by using first-order exponential decay kinetics with an estimated half-life of dioxin. Mean values for the continuous exposure probability indexes were significantly greater among veterans judged to be exposed according to self-reported job titles and specific military experiences than among men judged unlikely to have been exposed. Probabilistic exposure indexes based on HERBS tape for classification of likely exposure to herbicides in South Vietnam during 1965-1971 appear to be well suited for comparative classification of veterans and hence for use in epidemiologic studies.

[The liver and environmental poisons]

For almost a century now numerous examples of acute and subacute hepatic injury from exposure to toxic agents in the occupational or non-occupational environment have been extensively studied and are well documented, but such events are comparatively rare. In contrast, epidemiological data associating exposure to environmental chemicals with chronic liver disease or primary hepatic malignancies in the human is scarce as compared with the vast body of literature concerning chronic pulmonary disease as a consequence of exposure at the workplace. Large-scale industrial production of many newly synthesized organic chemicals began during the period 1930-1940 but it was not until the 1960s that the output increased exponentially. Consequently, the spectrum of environmental influences is gaining increasing complexity since simultaneous or sequential exposure to a variety of pollutants is becoming the rule rather than the exception. Possible interaction or synergism of environmental agents--even of those which in themselves or for their low dosage level may be considered "harmless" - and particularly latency periods of more than one decade further complicate preventive strategies. The liver, as the central site for the biotransformation of xenobiotics, deserves special attention when new chemicals which are to be introduced into the environment are being tested for their potential toxicity, especially since many hepatotoxic agents have been shown to undergo bioactivation in the liver. Currently available information on hepatic injury due to environmental agents is briefly reviewed and comprises solvents and degreasing agents, pesticides, polyhalogenated biphenyls, dioxins and dibenzofuranes, epoxy resin hardeners, vinyl chloride, naturally occurring hepatotoxins in plants and fungi, herbal medicines and traditional remedies and a side-light on the Reye syndrome and the Spanish "toxic oil syndrome".

Chloracne and chloracnegens

Chloracne, an acneform eruption resulting from poisoning by halogenated aromatic compounds, has been a considerable problem over the last 40 years. The condition is always a symptom of systemic poisoning and should be familiar to all practitioners, particularly dermatologists. It is difficult to treat and can last for long periods without known additional exposure to chloracnegens. Some chloracnegens are capable of causing a variety of systemic signs and symptoms and may be oncogenic. Although there are probably fewer than 4,000 persons with chloracne worldwide, those found with the disorder should be evaluated medically on a regular basis and followed, if possible, throughout their lives.

TCDD (2,3,7,8-tetrachlorodibenzo-p-dioxin) reduces lipoprotein lipase activity in the adipose tissue of the guinea pig

TCDD (2,3,7,8-tetrachlorodibenzo-p-dioxin) administered to young male guinea pigs at a dose of 1 microgram/kg (single intraperitoneal injection) caused a large reduction in adipose tissue lipoprotein lipase (LPL) activity. This effect occurred rapidly; a 70% decrease was noticed after 24 hour and 80% of LPL activity was lost by 48 hours when the serum triglyceride levels increased to 175% of control levels. LPL is known to play an important role in controlling the amount of free fatty acids supplied to adipose tissues. Administration of a large dose of glucose to fasted guinea pigs, which have shown a similar weight loss, but less LPL loss than TCDD-treated animals, had the effect of elevating their adipose LPL levels back to a near normal level, whereas the same treatment caused no significant increase in the LPL levels of TCDD-treated animals. Evidence indicates that the TCDD-caused decline in LPL activity is irreversible. As a consequence, the affected guinea pigs are incapable of responding to changes in nutritional status.

Lipid abnormalities in workers exposed to dioxin

Ten years after an incident in which workers were exposed to tetrachlorodibenzodioxin (TCDD) a controlled biochemical study showed statistically significant increases in the serum cholesterol and triglyceride concentrations of workers both with and without chloracne. Urinary excretion of D-glucaric acid was significantly higher for all workers.

Cutaneous signs of systemic toxicity due to dioxins and related chemicals

The controversy about dioxin effects on human health received a great deal of attention recently when the State of Missouri was declared to have a dioxin crisis. However, dioxin and several related chemicals are widespread throughout the world. Cutaneous signs play an important part in evaluating toxicity of dioxin and similar chemicals. Chloracne is the most sensitive indicator of significant dioxin exposure. Porphyria cutanea tarda and hyperpigmentation are other known cutaneous effects, and malignant fibrous histiocytomas of the skin may possibly be associated, although data are inconclusive on this point. The AMC Council on Scientific Affairs recommended that all physicians become familiar with chloracne and other toxic effects of dioxin. Dermatologists, especially, should be aware of the problem and may discover early cases of previously unsuspected exposure to this group of chemicals.

Health implications of 2,3,7,8-tetrachlorodibenzodioxin (TCDD) contamination of residential soil

Extrapolations from animal toxicity experiments (including carcinogenicity and reproductive effects) to possible human heath effects can be used to estimate a reasonable level of risk for 2,3,7,8-tetrachlorodibenzodioxin (2,3,7,8-TCDD). Extrapolations are derived from: (1) review of published studies, (2) a complex set of assumptions related to human exposure to contaminated soil, and (3) estimates of (a) a dose response curve, (b) appropriate margins of safety, and/or (c) applicable mechanisms of action. One ppb of 2,3,7,8-TCDD in soil is a reasonable level at which to begin consideration of action to limit human exposure for contaminated soil.

Health status of workers with past exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin in the manufacture of 2,4,5-trichlorophenoxyacetic acid: comparison of findings with and without chloracne

Chloracne was found in 52% of 226 workers in a 1979 cross-sectional survey at a plant where 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) had been manufactured from 1948 to 1969. Mean duration of residual chloracne was 26 years, and in 29 subjects, it had been present for 30 years. A significant increased prevalence of abnormal gamma-glutamyl transpeptidase (GGT) and higher mean GGT were found in those with chloracne, compared to those without. Although mean triglyceride values were higher in those with chloracne, the difference was not statistically significant. Neurological examination showed a statistically significant higher prevalence of abnormal sensory findings in those with chloracne. Increased prevalence of angina and reported myocardial infarction in those with chloracne was not significant when age-adjusted. Increased prevalence of reported sexual dysfunction and decreased libido in those with chloracne compared to those without was statistically significant after age adjustment. No differences were found between those with and without chloracne in serum cholesterol, total urinary porphyrins, or in reproductive outcome.

Immunoreactive uroporphyrinogen decarboxylase in porphyria cutanea tarda

Immunoreactive uroporphyrinogen decarboxylase was measured by rocket immuno-electrophoresis in haemolysates from 7 unrelated patients with familial porphyria cutanea tarda (PCT), 6 patients with sporadic PCT, and 7 normal subjects. In all patients with familial PCT immunoreactive enzyme protein was decreased (51% of normal), to the same extent as catalytic activity (56% of normal), whereas in sporadic PCT both measurements were normal. These results show that familial PCT is commonly caused by a mutation which does not lead to the production of non-catalytic cross-reactive immunological material. Familial PCT can be distinguished from other types of PCT by a simple immunoelectrophoretic method that does not involve measurement of uroporphyrinogen decarboxylase activity and which is therefore likely to be suitable for routine diagnostic use.

Liquid chromatography of urinary porphyrins for the biological monitoring of occupational exposure to porphyrinogenic substances

Very sensitive and precise analytical methods for measuring total porphyrin excretion and the relative amounts of different porphyrins in urine are required in order to monitor the biological effects of porphyrinogenic substances in workers and the general population. Many analytical steps of a HPLC method for measuring porphyrins as methyl esters in urine have been perfected. Sensitivity is 0.1 microgram/1 for each type of porphyrin, and average recovery is 92% in the range of 50-450 micrograms/liter porphyrins. The coefficient of variation is 3.4% within a series and 12.5% between series. Chemical oxidation before analysis and appropriate storing of the samples are the key points in achieving high quality results. The urinary excretion of porphyrins in healthy male workers varies within the range 21 to 161 micrograms/liter (95% limits of a group of 78 subjects). Concomitant factors, like drug use or liver disorders, were found to alter urinary porphyrin excretion. The proposed method permits the detection of extremely small alterations in porphyrin excretion resulting from occupational exposure to industrial chemicals such as, for example, mild coproporphyrinuria or early stages of chemical porphyria induced by polyhalogenated arylhydrocarbons.

Evaluation of a detoxification regimen for fat stored xenobiotics

A detoxification regimen has been found to be safe for use by individuals exposed to recreational (abused) and medical drugs, patent medicines, occupational and environmental chemicals. Patients with high blood pressure had a mean reduction of 30.8 mm systolic, 23.3 mm diastolic. Cholesterol level mean reduction was 19.5 mg/100ml, while triglycerides did not change. Medical complications associated with the program were rare, occurring in less than three percent of the subjects. The program resulted in improvements in psychological test scores. The mean increase in Wechsler Adult Intelligence Scale IQ was 6.7 points. High Minnesota Multiphasic Personality Inventory profiles decreased on the third scale (10.7), the fourth scale (8.0), the fifth scale (4.5) and the sixth scale (8.0). The decrease in the fourth scale suggests hope for sociopaths, a group with fourth scale scores not improved by National Institute for Mental Health or Narcotic Addict Rehabilitation Act inpatient programs.