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PENTACHLOROPHENOL
CAS No: 87-86-5
I. PHYSICAL AND CHEMICAL PROPERTIES (From HSDB, 1995)
Molecular weight 266.35
Boiling point 309°C
Melting point 190°C
Vapor pressure 0.00011 mm Hg @ 25°C
Air concentration conversion 1 ppm = 10.9 mg/m 3 @ 25°C
II.
HEALTH ASSESSMENT VALUES
Unit Risk Factor: 4.6 E-6 (µg/m 3 ) -1
Slope Factor: 1.8 E-2 (mg/kg-day) -1
[Calculated from a cancer potency factor derived by CDHS (1991) from male mouse liver
tumor data (NTP, 1989) using a linearized multistage procedure.]
III.
CARCINOGENIC EFFECTS
Human Studies
No human epidemiological studies were located that were adequate to evaluate a possible association
between exposure to pentachlorophenol and cancer.
Animal Studies
The National Toxicology Program (NTP, 1989) conducted 2 studies on the carcinogenic effects of
lifetime exposure of mice to pentachlorophenol (PeCP). In these studies, B6C3F 1 mice were exposed
to dietary PeCP, as either the technical grade or EC-7 grade, for 2 years. The technical grade PeCP
contained polychlorinated dibenzodioxins (PCDDs) and dibenzofurans (PCDFs) as contaminants in
significantly higher concentrations than the EC-7 grade. The NTP found dose-related increases in liver
and adrenal medullary tumors in male and female mice, and an increase in hemangiosarcomas in the
females exposed to the EC-7 grade (Table 1). The incidence of liver neoplasms and
hemangiosarcomas was higher in female mice exposed to technical grade PeCP. The incidence of
hemoangiosarcomas in female mice was 0/35, 3/50, and 6/50 for the 0, 100, and 200 ppm PeCP
groups, respectively.
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