Morbidity in former sawmill workers exposed to pentachlorophenol (PCP): a cross-sectional study in New Zealand

BACKGROUND

From 1950 to 1990 pentachlorophenol (PCP) was used widely in the New Zealand sawmill industry, and persistent claims of long-term health effects have been made.

METHODS

We surveyed surviving members of a cohort enumerated to study mortality in sawmill workers employed from 1970 to 1990. Estimates of historical exposure were based on job titles held, using the results of a PCP biomonitoring survey conducted in the 1980s. The survey involved interviews and clinical examinations, with interviewers and examiners blinded to exposure status.

RESULTS

Of the 293 participants 177 had not been exposed, and of the 116 exposed all but 10% had low or short-term PCP exposure. Nevertheless, a number of significant associations between PCP exposure and the prevalence of various symptoms were observed including associations between: (i) exposure levels and self-reported tuberculosis, pleurisy or pneumonia (P < 0.01) and a deficit in cranial nerve function (P = 0.04); (ii) duration of employment and thyroid disorders (P = 0.04), and neuropsychological symptoms including often going back to check things (P = 0.04), low libido (P = 0.02) and heart palpitations (P = 0.02), and a strong dose-response trend for frequent mood changes without cause (P < 0.01); and (iii) cumulative exposure and frequent mood changes without cause (P = 0.02), low libido (P = 0.04), and in the overall number of neuropsychological symptoms reported (P = 0.03).

CONCLUSIONS

PCP exposure was associated with a number of physical and neuropsychological health effects that persisted long after exposure had ceased.

Accident insurance, sickness, and science: New Zealand's no-fault system

This article explores the process of seeking compensation for occupational illness under a no-fault accident insurance scheme. The author uses two case studies--firefighters who attended a fire at a chemical storage depot and timbermill workers who worked with pentachlorophenol--to illustrate how science can be used to deny compensation to sick and dying workers. The results of the studies suggest that a no-fault accident compensation scheme, considered to be a victory for workers, offers no guarantee of just outcomes for working people. And science can be co-opted and used to support business and state interests against workers; this ideological support is increasingly hidden behind the development of "objective" systems of assessing compensation claims.

Assessment of pentachlorophenol-exposed timber workers using a test-of-poisoning model

Sixty-two former New Zealand timber workers who were exposed to pentachlorophenol (PCP) at work were interviewed, examined, and assessed both by laboratory investigations and psychometrically for clinical syndromes that could be related to PCP exposure. Three such syndromes were identified: an acute complex of fever, headaches, upper and lower respiratory tract and eye irritation, skin disease, and foul smelling and discolored sweat; a chronic fatigue syndrome, beginning while still at work and frequently persisting; and a delayed encephalopathy. Neither of the sustained syndromes was considered characteristic of PCP poisoning, and many confounders were identified. An exposure index and a test-of-poisoning score had a statistically insignificant correlation.

[Pentachlorophenol poisoning. Report of 4 cases and review of the literature]

Pentachlorophenol (PCP) was, and still is, one of the most frequently used fungicides and pesticides. The use of PCP has been more restricted during the last few years. PCP's most important industrial application is as a wood preservative. The pentachlorophenol can be absorbed into the body by all the routes of occupational exposure. Some epidemiological observations suggest that exposure to PCP solutions may result in an increased risk for certain diseases in humans, e.g., immunodeficiency, blood disorders, malignancies, congenital anomalies. Chronic poisoning is difficult to detect since symptoms are often vague. Acute poisoning is due to interference with oxidative phosphorylation and can present itself as an unexpected case of sudden death. Four cases of PCP poisoning, including one fatalitie, occurred in two small wood preservative plants. All cases presented with increased serum creatinine phosphokinasa. The clinical finding are reported, and treatment modalities commented. At present there is no antidote for PCP. The basis for treatment is intensive supportive care to maintain vital bodily function. In one patient plasmapheresis was used and rapid recover was obtained. It is suggested that such therapy may be lifesaving in such intoxications.

Human pentachlorophenol poisoning

Pentachlorophenol (PCP) was, and still is, one of the most frequently used fungicides and pesticides. Its toxicity is due to interference with oxidative phosphorylation. Acute and chronic poisoning may occur by dermal absorption, inhalation or ingestion. Chronic poisoning occurs mainly in sawmill workers or people living in log homes treated with PCP-containing wood protecting formulations. Quantitative determination of PCP in urine and serum is useful to detect occupational or subclinical exposure. The clinical features of acute and chronic PCP poisoning can be classified systematically into effects on the skin, metabolism (fever), the haematopoietic tissue, the respiratory system, the central and peripheral nervous system, the kidney and the gastrointestinal tract. Although PCP is not classified as a human carcinogen, some epidemiological observations suggest that exposure to chlorophenols in general and PCP solutions in particular may result in an increased risk for certain malignant disorders such as nasal carcinoma and soft tissue sarcoma. There is concern that contamination of PCP-solutions with products such as chlorodibenzo-p-dioxins is the real cause of this suspected carcinogenicity. No specific antidote exists for the treatment of (acute) PCP poisoning. The basis of the treatment of acute poisoning is intensive supportive care with prevention of dangerous rise in temperature. Use of PCP-based products as indoor wood preservatives poses an unacceptable risk to human health.

Dioxin intoxication from chronic exposure of horses to pentachlorophenol-contaminated wood shavings

Investigations into the cause of health problems on a horse-breeding farm led to the discovery of high concentrations (630 to 9,810 mg/kg of bedding) of pentachlorophenol in wood shavings used as bedding for horses over a period of 2 to 4 years. Toxicologic signs in the horses were characteristic of toxic effects associated with exposure of polychlorinated dibenzo-p-dioxins and dibenzofurans. Tissue residue analysis confirmed presence of toxic polychlorinated dibenzo-p-dioxin and dibenzofuran isomers known to be in pentachlorophenol, substantiating the bioavailability of polychlorinated dibenzo-p-dioxins and dibenzofurans in the wood shavings. The findings provide evidence that residue concentrations in the range of 2 ng/g of toxic polychlorinated dibenzo-p-dioxin isomers in liver or fat correlate with toxicologic effects in horses.

Aplastic anaemia associated with organochlorine pesticide: case reports and review of evidence

Three patients with aplastic anaemia had a history of substantial previous exposure to organochlorine pesticides. The temporal association between chemical exposure and the onset of first symptoms of anaemia was strongly supportive. Organochlorines have the property of lipid affinity and accumulation in adipose tissue. Objective evidence of clinically important concentrations of tissue pesticide residues may be a useful confirmation of previous exposure. In the patients studied the presence of Lindane (gamma hexachlorocyclohexane) was shown using gas chromatography/mass spectrometry with selective ion monitoring of fragments obtained from one heavily exposed patient, with concentrations about five times greater than a matched control. The presence of clinically important tissue concentrations of pentachlorophenol was also confirmed in a second patient exposed to this agent. The long term safety of organochlorine pesticides remains doubtful as they were introduced before adequate toxicological screening tests had been developed. The central registration of possible haematological adverse reactions, however, forms an important epidemiological method in the study of environmental chemical hazards and should be complied with whenever possible.

[Toxic environmental factors in sudden infant death (SIDS)]

The increasing number of discussions on the influence of toxic environmental factors, including SIDS, prompted systematic postmortem chemical-toxicological investigations to be carried out on 54 SIDS cases and 2 control cases of the same age group. Tissue levels of arsenic, lead, cadmium, mercury, and pentachlorphenol, as well as other organic noxious agents, were measured in several organs. In addition, the COHb concentrations were determined. In spite of the widely scattered values, the extreme levels measured and the arithmetic means and median averages of As, Pb, Cd, Hg, PCP, and COHb had no more range in concentrations than can be expected for toxic effects - according to present knowledge anyway. It was observed that infants from an urban environment showed no greater concentration of noxious agents than did infants from rural regions. There were also no differences between SIDS cases and the controls, nor was there a correlation between infections of the respiratory system that are often morphologically detected - including laryngitis - and higher concentrations of these agents in the organs of SIDS cases.

Pentachlorophenol intoxication: report of a fatal case, with comments on the clinical course and pathologic anatomy

A case of a 33-yr-old man who died following occupational exposure to pentachlorophenol is presented. Postmortem examination revealed cerebral edema and fatty degeneration of the viscera. Review of the literature indicates that the clinical syndrome of poisoning with the compound results from mitochondrial toxicity with derangement of aerobic metabolism.

Pentachlorophenol poisoning

Pentachlorophenol (PCP) is a pesticide commonly used as a wood preservative. Although exposure has been well controlled in large chemical manufacturing plants, over-exposures have recently becomes a concern at smaller facilities. Five cases of PCP poisoning, including two fatalities, occurred in two small wood preservative plants. All cases presented with fever, including severe hyperpyrexia in two; an increased anion gap and renal insufficiency were noted in two others. PCP may uncouple oxidative phosphorylation, resulting in a poisoning syndrome characterized by hyperpyrexia, diaphoresis, tachycardia, tachypnea, abdominal pain, nausea, and even death.

Pesticide poisoning of livestock: a review of cases investigated

The cases of suspected poisoning of livestock by a range of organic chemicals, mainly pesticides, investigated at the Central Veterinary Laboratory during the period 1977 to 1980 are reviewed. The incidences of poisoning by various types of compound and the species most at risk are discussed. Organophosphorus pesticides and rodenticides were the commonest causes of poisoning. Pesticides accounted for one in 25 of all fatal poisonings listed by the veterinary investigation diagnosis analysis (VIDA) of the Ministry of Agriculture, Fisheries and Food.

[Investigations on neurotoxicity of chemical substances at the workplace. II. Determination of the motor and sensory nerve conduction velocity in persons occupationally exposed to pentachlorophenol (author's transl)]

We examined eighteen workers (three women, 15 men) in a pentachlorophenol (PCP) processing factory, with a mean activity of 12 years. PCP in blood and urine samples was analyzed by gas chromatography. To evaluate the peripheral nervous system the maximal motor as well as sensory nerve conduction velocities of the ulnar and/or median nerve were measured. The PCP-levels in plasma ranged between 0.02 and 1.5 ng/l, median 0.25 ng/l, and in urine between 13 and 1,224 micrograms/l, median 112 micrograms/l, or between 11 and 2,111 micrograms/g creatinine, median 111 micrograms/g creatinine. The median values of the neurophysiological parameters showed a mild degree of slowing in the PCP-collective. In the case of the sensory nerve conduction velocities, this decrease was significant. A dose-effect relationship between internal PCP-load and the different nerve conduction velocities could not be demonstrated. The individual evaluation of the toxicological and neurophysiological results gave hints that in some cases decreased nerve conduction velocity is caused by chronic exposure to PCP.

Clinical findings in workers exposed to pentachlorophenol

Comparative findings are presented on the health and exposure status of groups of individuals in Hawaii with and without occupational exposure to pentachlorophenol (PCP). Occupational exposure to PCP occurred through employment at firms engaged in the treatment of wood with either PCP alone or PCP plus other compounds as preservative chemicals. Mean serum levels were 0.32 ppm for 32 control individuals, 1.72 ppm for 24 workers exposed to PCP and other wood preservative chemicals, and 3.78 ppm for 22 workers exposed to PCP as the sole preservative chemical. Age-standardized prevalence rates were significantly higher among the PCP-exposed than among the controls for low-grade infections or inflammations of the skin and subcutaneous tissue, protective membrane of the eyes and the mucosa membrane of the upper respiratory tract. Strong to moderate statistical associations were observed between PCP exposure and increased occurrence of bands (immature leucocytes) and basophils, increased plasma cholinesterase, alkaline phosphatase, gamma globulin and uric acid, and decreased serum calcium. Despite these statistical associations, laboratory values considered to be clinically abnormal were few and not significantly greater in occurrence among the PCP-exposed individuals.

[Pentachlorophenol poisoning in nestlings of canaries (Serinus canarius) (author's transl)]

Using binder twine of bales of straw as nesting material for canaries apparently resulted in a reduction of hatchability. However, the outstanding feature was the high mortality rate during the first week after hatching, with a peak on the fourth day and nestlings never growing any older than three months. Other symptoms consisted in marked retardation of growth and poor growth of feathers. The adult birds presented a normal appearance. The most likely cause was the presence of pentachlorophenol (PCP) averaging 285 ppm).

A pharmacokinetic study of pentachlorophenol poisoning and the effect of forced diuresis

A pharmacokinetic study of an intentional pentachlorophenol ingestion by an elderly human has been undertaken. Information on the presence or absence of forced diuresis either continuously or for a short restricted period indicates that such treatment would materially reduce the body burden of pentachlorophenol. It is suggested that forced diuresis is the treatment of preference for such intoxication at this time.

[Chloracne, porphyria cutanea tarda, and other poisonings due to the herbicides]

In 80 industrial workers producing herbicides (2,4,5-trichlorphenoxyaceticacidsodium and sodiumpentachlorphenolate) in Czechoslovakia the following signs of intoxication caused by 2,3,6,7-tetrachlordibenzodioxin were found: Dermatological: Chloracne and Porphyria cutanea tarda. Internal: Disorders of the metabolism of porphyrins, fats, carbohydrates, plasmaproteins. Neurological: Mainly lesions of the peripheral neurone. Psychiatric: Neurasthenic syndrome and organic lesions. Differences from the usual course of chloracne were observed. Porphyria cutanea tarda acquisita was most obvious, one patient suffered and died from severe atherosclerosis, hypertension and diabetes. Many patients developed polyneuropathy, as verified both by EMG and autopsy. Two patients died from bronchogenic carcinoma.