Wood preservation facilities, pentachlorophenol pressure: chapter E-2

2. Physical and Chemical Properties

PCP is a solid at room temperature. It can be characterized as a stable organic compound that is sparingly soluble in water and highly soluble in organic solvents. It adsorbs strongly to organic solids such as cellulose in wood.

PCP is chemically and biologically persistent at high concentrations (i.e. the 5-9% concentrations used for treatment of wood). Its persistence in treated wood and its toxicity to wood decay organisms are two major reasons for the use of PCP as a wood preservative. However, it is photodegradable and at low concentrations is also biodegradable.

The physical and chemical properties listed below must be given special consideration during handling and contingency planning:

• the ability of PCP to dissolve in water; dissolution increases as pH and temperature increase
• the high solubility of PCP in oils, including skin oils, which enhances its ability to penetrate skin following dermal contact
• the potential to form toxic fumes upon exposure to fires and high temperatures (i.e. over 350°C)
• a vapour pressure (although low at room temperature) that will result in a small degree of sublimation of PCP

The physical and chemical properties of PCP are outlined in Table 2 (6, 7). General physical and chemical properties can be obtained from manufacturers’ material safety data sheets (MSDS) and from labels for pesticide products. Electronic copies of the pesticide label can be obtained from the Health Canada website.