Pentachlorophenol (PCP) can be found in two forms: pentachlorophenol
itself or as the sodium salt of pentachlorophenol
(NaPCP). These two forms have some different physical
properties, but are expected to have similar toxic effects. PCP is
a synthetic substance, made from other chemicals, and does
not occur naturally in the environment. Although PCP was first
synthesized in 1841, it was not produced commercially until
1936. It has since been registered for use as an insecticide,
fungicide, herbicide, algicide, and disinfectant. By 1967, PCP
and its sodium salt, NaPCP, were used extensively in industry
and agriculture, due in large part to the solubility of PCP in
organic solvents and of NaPCP in water. In 1977, both were
listed together as the second most heavily used pesticide in the
United States.
Sodium pentachlorophenate is a crystalline solid. Phenolic odor.
White or tan powder. Soluble in water,
ethanol, and acetone; insoluble in benzene.
Fungicide; herbicide; slimicide; fermentation
disinfectant, especially in finishes and papers.
PCP and its water soluble salt, NaPCP, are commercially
produced organochlorine compounds used primarily as the
preservatives of wood and wood products, and secondarily
as herbicides, insecticides, fungicides, molluscicides, and
bactericides.
Sodium pentachlorophenolate is a white or tan, powdered solid. Sodium pentachlorophenolate is soluble in water and may burn, but Sodium pentachlorophenolate is not easily ignited. Sodium pentachlorophenolate may be toxic by ingestion, inhalation and skin absorption. Sodium pentachlorophenolate is used as a fungicide, herbicide and as a disinfectant.
Sodium pentachlorophenolate is incompatible with strong oxidizing agents.
Toxic by ingestion, inhalation; skin irritant.
Exposure can cause irritation of eyes, nose and throat. May cause weakness, excessive sweating, headache, dizziness, nausea, vomiting, and difficulty in breathing.
Special Hazards of Combustion Products: Irritating vapors and toxic gases, such as hydrogen chloride, polychlorodibenzodioxins and carbon monoxide, may be formed when involved in fire.
Poison by ingestion, inhalation, skin contact, intravenous, intraperitoneal, subcutaneous, and intratracheal routes. An experimental teratogen. Experimental reproductive effects. Mutation data reported. When heated to decomposition it emits toxic fumes of Cland Na2O. See also CHLOROPHENOLS.
Uses include: wood preservative; as a fungicide in water-based latex paints; preservation of cellulose products, textiles, adhesives, leather, pulp, paper, and industrial waste systems; a contact and preemergence herbicide; general disinfectant and control of the intermediate snail host of schistosomiasis. The technical grade of sodium pentachlorophenate usually contain toxic microcontaminants including polychlorinated dibenzodioxins and dibenzofurans (132-64-9, and others).
Data from a wide range and
large number of studies evaluating the carcinogenic potential
of pentachlorophenol are available. These include three longterm
carcinogenicity studies in mice, three in
rats, two studies evaluating the potential
of pentachlorophenol to act as promoter in the carcinogenic
process, and a “stop exposure” study. The
results of the initiation and/or promotion studies are uniformly
negative, as are the results of all the rat studies and two
of the three long-term mouse studies. In addition, a very large
body of genotoxicity evidence suggests that pentachlorophenol
is nonmutagenic.
Routes and pathways, relevant physicochemical properties
Solubility: in water 330 g l-1 at 25 °C; soluble in ethanol,
acetone; insoluble in benzene and petroleum oils.
Partition behavior in water, sediment, and soil
If released to air, NaPCP will exist solely in the aerosol
phase in the ambient atmosphere. The aerosol phase will be
removed from the atmosphere by wet and dry deposition. If released to soil and water under typical ambient conditions
(pH 5–9), NaPCP is expected to exist predominately in
its dissociated form (pKa 4.7). Releases to soil can decrease
in concentration due to slow biodegradation (half-life is
weeks to months) and leaching into groundwater. Releases
to water may photolyze (half-life is hours to days with
rate decreasing with depth of water), biodegrade, adsorb
to sediments, or bioaccumulate in aquatic organisms.
Biodegradation probably becomes significant after a period
of acclimation.
Environmental persistency
NaPCP is not persistent in water, sewage, or soil because of
bacterial decomposition. PCP readily decomposes in sunlight
to monomeric and dimeric oxidation products in water.
Principal decompose products are tetrachlororesorcinol,
chloranilic acid, and dimeric products.
Bioaccumulation and biomagnification
Sodium pentachlorophenol did not appear to bioaccumulate
in aquatic organisms to very high concentrations.
BCFs for the compound were <1000 for most species
tested.
UN2567 Sodium pentachlorophenate, Hazard Class: 6.1; Labels: 6.1-Poisonous materials
The biochemical action of pentachlorophenol is active
uncoupling of oxidation phosphorylation. PCP binds to
mitochondrial protein and inhibits mitochondrial ATP-ase
activity. Thus, both the formation of ATP and the release of
energy to the cell from the breakdown of ATP to ADP are
prevented. Electron transport is not inhibited by PCP, although
reactions dependent on available high-energy bonds, such as
oxidative and glycolytic phosphorylation, are affected. Binding
to enzymatic protein has been reported and may lead to the
inhibition of other cellular enzymes. There is also an increase in
cellular oxygen demand during the uncoupling of oxidative
phosphorylation. This causes the initial rise in respiration rate
reported in individuals poisoned by PCP.
Uses include: wood preservative; as a fungicide in water-based latex paints; preservation of cellulose products, textiles, adhesives, leather, pulp, paper, and industrial waste systems; a contact and preemergence herbicide; general disinfectant and control of the intermediate snail host of schistosomiasis. The technical grade of sodium pentachlorophenate usually contain toxic microcontaminants including polychlorinated dibenzodioxins and dibenzofurans (132-64-9, and others).
Consult with environmental regulatory agencies for guidance on acceptable disposal practices. Generators of waste containing this contaminant (≥100 kg/mo) must conform to EPA regulations governing storage, transportation, treatment, and waste disposal.
