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EXTOXNET PIP -PENTACHLOROPHENOL (PCP) Page 2 of 5
<br /> Toxicological Effects:
<br /> . Acute toxicity: Pentachlorophenol is moderately toxic via the oral route,with reported oral LD50
<br /> values for various formulations ranging from 27 to 211 mg/kg in rats [69,70]. In mice the oral
<br /> LD50 is 74 to 130 mg/kg, and in rabbits 70 to 300 mg/kg [69,70[. It is moderately toxic via
<br /> inhalation as well,with a reported inhalation LC50 of 0.2 to 2.1 mg/L in rats [17]. The time frame
<br /> for this LC50 (e.g., 4-hour, 1-hour, etc.)was not given. Inhalation LD50 values(i.e., the median
<br /> lethal doses,not concentrations, via the inhalation route) of 225 mg/kg in rats and 355 mg/kg in
<br /> mice are reported, also without a time frame [70]. Another calculated LD50 in rats via the
<br /> inhalation route is 11.7 mg/kg for 28 to 44 minutes of exposure, assuming a breathing rate of 80
<br /> mL/minute [69]. Pentachlorophenol causes irritation to the mucous membranes, skin, and eyes of
<br /> test animals [9]. Via the dermal route, it is moderately toxic, with reported dermal LD50 values
<br /> ranging from 96-330 mg/kg in the rat, and 40 to greater than 1000 mg/kg in the rabbit(depending
<br /> on formulation) [69]. Skin penetration may be the most dangerous route of exposure,being
<br /> responsible for about 50 known cases of PCP poisoning, 30 of which have resulted in death.
<br /> Immersion of a human hand in a 0.4 percent PCP solution for 10 minutes caused pain and
<br /> inflammation. Technical PCP resulted in chloracne on the ears of rabbits, and edema in chicks,but
<br /> pure PCP did not [70]. High acute exposure to PCP can cause elevated temperature,profuse
<br /> sweating, dehydration, loss of appetite, decreased body weight,nausea, and neurological effects
<br /> such as tremors, uncoordinated movement, leg pain, muscle twitching, and coma[69,70]. Some of
<br /> the symptoms may be due to the impurities in the formulation, rather than the pentachlorophenol
<br /> itself[69].
<br /> • Chronic toxicity: Much research on PCP has been performed with poorly characterized technical
<br /> material, and the chronic toxicity observed may depend in large measure on the proportion of
<br /> chlorodibenzo-p-dioxins present in the mixture [69]. In a 90-day feeding trial in rats, 30
<br /> mg/kg/day produced depressed red blood cell and hemoglobin levels as well as liver degeneration,
<br /> and even lower doses resulted in irregular blood chemistry and enzyme levels, along with
<br /> increased liver and kidney weights [69,71]. Pure PCP, and also technical PCP without dioxin
<br /> contamination,produced only slight enlargement of livers and kidneys [69]. Purified PCP also did
<br /> not produce toxic effects such as liver damage and immune system alterations,which had
<br /> previously been reported for the technical product [69,71]. In humans, the most common exposure
<br /> to PCP is inhalation in the workplace. Abdominal pain, nausea, fever, and respiratory irritation, as
<br /> well as eye, skin, and throat irritation,may result from such exposure [70], while very high levels
<br /> may cause obstruction of the circulatory system in the lungs and cause heart failure [70].
<br /> Survivors of toxic exposures may suffer permanent visual and central nervous system damage
<br /> [70]. Persons regularly exposed to PCP tend to tolerate higher levels of PCP vapors than persons
<br /> having little contact with these vapors [70,71].
<br /> • Reproductive effects: Rats fed PCP at doses of 30 mg/kg/day for 62 days before mating and
<br /> during lactation showed weight loss,but no decreases in fecundity and fertility [69]. Sperm of
<br /> male mice given technical or purified PCP for 5 days at 50 mg/kg/day showed no abnormalities
<br /> within 35 days of treatment [69]. The evidence indicates that PCP does not cause reproductive
<br /> effects.
<br /> • Teratogenic effects: Offspring of rats fed PCP at doses of 30 mg/kg/day for 62 days before
<br /> mating and during lactation showed lowered survival and growth rates [69]; 3 mg/kg/day did not
<br /> have any effects [69]. Maternal doses of 5 mg/kg/day of technical PCP in rats produced toxicity to
<br /> the fetus or embryo, and 50 mg/kg/day on days 6 to 15, 8 to 11 or 12 to 15 of gestation produced
<br /> increases resorptions, swelling, dilated ureters, and skeletal anomalies [69]. It is unlikely that PCP
<br /> has teratogenic effects in humans at normal exposure levels.
<br /> • Mutagenic effects: PCP is not mutagenic in bacteria or houseflies, but is weakly mutagenic in
<br /> mice and may be mutagenic in yeast [71]. One study of chromosomal aberrations in
<br /> occupationally exposed workers showed no increased incidence of sister-chromatid exchanges,
<br /> http://extoxnet,orst.edu/pips/pentachl.htm 5/8/2008
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