Pentaclorofenolo: stato attuale delle conoscenze

Largely produced and used as a 'universal biocide', pentachlorophenol (PCP) is under investigation as possible carcinogenic agent for man, after Scandinavian studies have shown that human exposure to chlorophenols might be associated with cancer and leukaemia. PCP is used mainly in the wood and tanning industries. Technical grade PCP may be contaminated by variable amounts of impurities, including chlorinated dioxins and furans. This makes it uncertain whether the acute and chronic effects observed in experimental animals can be ascribed to PCP itself or to its contaminants. The acute toxic effects of PCP are due to uncoupling of oxidative phosphorylation. The porphyrogenic and acnigenic activity shown by the commercial products appears to be related to the presence of contaminants. Both pure and technical grade PCP induce toxic damage to the liver and changes in the immunological system. Analytical grade PCP has been found to be teratogenic in animals. Analogous effects have also been caused by hexachlorodibenzodioxin, one of the main contaminants of PCP. So far, the carcinogenic activity of PCP has not been sufficiently studied. Experimental investigations in animals are few and of questionable value. Human epidemiological data address multiple exposure situations, where the significance of PCP exposure cannot be easily singled out. Therefore the question is still open and further research is needed. Absorption of PCP in humans may occur through inhalation, skin penetration and via the digestive system. PCP is metabolized in the organism only to a limited extent and is mostly excreted unchanged with the urine. Human exposure is not confined to work settings. Although environmental persistence of PCP is rather short, minimal amounts of PCP can be traced almost everywhere in the environment and in human tissues. PCP may dissipate in the environment from waste disposal, treated wood or other sources. Release of PCP from treated wood may be of importance as a source of human exposure for countries where log homes are popular. PCP can be detected in environmental samples using sensitive and specific analytical methods; these methods can also be adapted for use in human biological monitoring by measuring the PCP concentration in blood and urine. The relationship between environmental exposure and PCP levels in body fluids is rather uncertain. Urinary PCP concentrations can be used for biological monitoring of exposed subjects. Health surveillance of workers exposed to PCP should be addressed mainly to the evaluation of skin disorders, liver function changes and nervous system alterations.