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EXTOXNET PIP -PENTACHLOROPHENOL (PCP) Page 3 of 5 u Saw/ while another did find increases [71]. Weak mutagenic effects were seen in human lymphocyte cultures exposed to PCP [71]. The evidence suggests that PCP is nonmutagenic or weakly mutagenic. . Carcinogenic effects: Studies of two formulated PCP products (Dowcide and Penta) showed increases in cancers of the spleen, liver, and adrenal gland in test mice or rats at doses of about 17 to 18 mg/kg/day [71]. These findings were not replicated for Dowcide in mice in a second study [71]. There have been reports of a possible association between occupational exposures to technical PCP and Hodgkin's disease, acute leukemia, and soft-tissue sarcoma, but confounding factors such as concurrent exposure to other substances makes interpretation of these data problematic [71].No convincing evidence of PCP's caricinogenic effects in humans is available [71]. Current evidence is not sufficient to assess the potential of PCP to cause carcinogenic effects in humans. . Organ toxicity: Data from animal studies indicate that the major target organs for PCP are the liver, kidneys, and central nervous system. . Fate in humans and animals: PCP is rapidly absorbed through the gastrointestinal tract following ingestion [71]. Accumulation is not common,but if it does occur, the major sites are the liver, kidneys,plasma protein, brain, spleen, and fat [69,71]. Unless kidney and liver functions are impaired,PCP is rapidly eliminated from blood and tissues, and is excreted,mainly unchanged or in conjugated form, via the urine [71]. Single doses of PCP have half-lives in blood of 15 hours in rats, 78 hours in monkeys, and 30 to 50 hours in humans [69]. Ecological Effects: . Effects on birds: The compound is slightly toxic to practically nontoxic to bird species. The reported 5-day dietary LC50 value in Japanese quail is greater than 5139 ppm [54]. Reported acute oral LD50 values for PCP are 380 mg/kg in mallard duck and 504 mg/kg in pheasant [55]. . Effects on aquatic organisms: PCP may be highly to very highly toxic to many species of fish; reported 96-hour LC50 values are 68 ug/L in chinook salmon, 52 ug/L in rainbow trout, 205 ug/L in fathead minnow, 68 ug/L in channel catfish, and 32 ug/L in bluegill sunfish [55]. Several species of fish, invertebrates, and algae have had levels of PCP that were significantly higher(up to 10,000 times)than the concentration in the surrounding waters [71]. Once absorbed by fish, pure PCP is rapidly excreted as is its metabolite,with a biological half-life of only 10 hours [71]. Biomagnification,that is the progressively higher concentration of a compound as it passes up the food chain, is not thought to be significant because of PCP's rapid break down in living organisms [70]. . Effects on other organisms: Cattle and other farm animals have ingested PCP by chewing and licking outdoor wood structures, or from being housed in wooden pens that were treated with PCP solutions. This has caused sickness and death in some of these animals [17]. Environmental Fate: . Breakdown in soil and groundwater: PCP is moderately persistent in the soil environment, with a reported field half-life of 45 days [15]. PCP degrades most rapidly in flooded or anaerobic (airless) soils, at higher temperatures and in the presence of organic matter in the soil [12,15]. Breakdown is mainly by anaerobic biodegradation; breakdown by sunlight and hydrolysis do not appear to be significant processes [15]. It is poorly sorbed at neutral and alkaline conditions, and may be mobile in many soils [12,15]. Sorption will be slightly greater(and mobility slightly lesser) in soils with higher proportions of soil organic matter [12]. The compound has been found in groundwater in California, Oregon, and Minnesota at very low concentrations ranging from http://extoxnet.orst.edu/pips/pentachl.htrn 5/8/2008