Pentachlorophenol Data Sheet

Source of Exposure

Pentachlorophenol production and use are of the order of 50 million lb per year. It is primarily used as a fungicide, bacteriocide, slimicide and herbicide. It is the major synthetic wood preservative treatment chemical in current use. It is found in a variety of product uses for its biocidal properties, including use in shoe leather, drilling muds, paper products, and certain food packaging.

As a result surface water and treated drinking water have been found to contain as much as 0.70 and 0.06 ppb, respectively, pentachlorophenol (Buhler et al., 1973). It is readily absorbed through the skin. Two cases of fatal poisonings and several non fatal cases occurred in a hospital nursery in which pentachlorophenol had been used as a fungicide in the laundry room and ultimately contacted infants through their diapers (Armstrong et al., 1969). In recent years it has become apparent that many commercial samples of pentachlorophenol are contaminated with polychlorinated dibenzodioxins and dibenzofurans (Buser, 1975), which are highly toxic in their own right.

Symptoms

The acute toxic effects resembles that produced by the nitrophenolic herbicides, marked increases in metabolic rate as the result of uncoupling of oxidative phosphorylation. Patients suffer from inordinate sweating, thirst, fever, headache, dizziness, vomiting, asthenia, weight loss, and myalgia of the legs. Pentachlorophenol has been shown to cause reproductive failures in rats and to exhibit neurotoxicity in dogs, sheep, and rats. Renal damage has been observed in occupationally exposed groups and a number of reports have been published linking environmental exposures with the development of aplastic anemia and related hematological toxic effects.

Although pentachlorophenol is highly toxic in its own right, some study suggests that the contaminants may be responsible for some of the toxic effects of the technical grade product. A comparison of effects of technical versus purified pentachlorophenol indicated that only the technical grade produced chloracne, chick edema, hepatic porphyria and increased relative liver weight (Johnson et al., 1973; Goldstein, 1976) Technical grade was also much more active as a liver enzyme inducer.

Disposition

Pentachlorophenol is readily absorbed after ingestion, inhalation or through intact skin. Pentachlorophenol and its oxicised metabolite, tetrachlorohydroquinone, are excreted in the urine in free and conjugated forms, with about 74% of a dose being excreted unchanged in 7 days. Urinary concentrations in 130 pest-control operators exposed to pentchlorophenol ranged from 0.003 to 35.7 ug/ml (mean 1.8).

Plasma concentrations of 0.99 to 9.1 ug/ml were reported in 6 occupationally exposedsubjects and blood concentrations of 0.34 to 6.0 ?g/ml were reported in 7 exposed workers (Clarke, 1986).

Toxic Levels

The fatal dose of pentachloroplhenol for laboratory animals ranges from 30 to 100 mg/kg. The current permissible exposure value for industrial workers is 1 mg/g creatinine.

The estimated minimum lethal dose is 1 g and maximum permissible atmospheric concentration is 0.5 mg/ml3. Blood concentrations greater than 30 ?g/ml are usually toxic.

References

-Armstrong, R.W.; Eichner, E.R.; Klein, D.E.; Barthel, W.F.; Bennett, J,V.; Jonsson, V.; Bruce, H.; and Loveless, L.E.: Pentachlorophenol poisoning in a nursery for newborn infants. II, Epidemiologic and toxicologic studies. J.Pediatr., 75:317-325, 1969.

-Clarke’s Isolation and Identification of Drugs, The Pharmaceutical Press, London, 1986.

-Buser, H.R.: Analysis of polychlorinated dibenzo-P-dioxins and dibenzofurans in chlorinated phenols by mass fragmentography. J.Chromatogr., 107:295-310, 1975.

-Johnson, R.L.; Gehring, P.J.; Kociba, R.J.; and Schwetz, B.A.: Chlorinated dibenzodioxins and pentachlorophenol. Environ.HealthPerspect., 5:171-175, 1973.

-Goldstein, J.A.: Effects of pentachlorophenol on hepatic drug metabolizing enzymes and prphyria related to contamination with chlorinated dibenzo-p-dioxins and dibenzofurans. Toxicol.Qppl.Pharmacol., 37:145-146, 1976.

-Buhler, D.R.; Rasmusson m>E.; and Nakaue, H.S.: Occurrence of hexachlorophene and pentachlorophenol in sewage and water. Environ.Sci.Technol., 7:929-934, 1973.