International Agency for Research on Cancer (IARC) - Summaries & Evaluations

ortho-PHENYLPHENOL (Group 3)

For definition of Groups, see Preamble Evaluation.

VOL.: 73 (1999) (p. 451)

Chem. Abstr. No.: 90-43-7
Chem. Abstr. Name: (1,1¢ -Biphenyl)-2-ol

Sodium ortho-phenylphenate 
Chem. Abstr. No.: 132-27-4
Chem. Abstr. Name: (1,1¢ -Biphenyl)-2-ol, sodium salt

5. Summary of Data Reported and Evaluation

5.1 Exposure data

Exposure to ortho-phenylphenol and its sodium salt may occur during their production and use as industrial and agricultural fungicides, germicides and disinfectants, and as chemical intermediates. ortho-Phenylphenol has been detected in some groundwater and drinking-water samples as well as in some fruits and juices.

5.2 Human carcinogenicity data

No data were available to the Working Group.

5.3 Animal carcinogenicity data

ortho-Phenylphenol was tested for carcinogenicity in one experiment in mice and two experiments in rats by administration in the diet. Benign and malignant bladder tumours were induced at significant incidence in male rats in one study. Sodium ortho-phenylphenate was tested in mice in one study and in rats in two studies. It induced tumours of the bladder and renal pelvis in male rats in both studies and a marginal increase in the incidence of bladder tumours in female rats in one of the studies. There was no evidence of carcinogenicity in mice.

Bladder carcinogenesis induced in male rats by administration of N-nitrosobutyl(4-hydroxybutyl)amine was enhanced by sodium ortho-phenylphenate but not by ortho-phenylphenol. In one study, dermal application of sodium ortho-phenylphenate enhanced skin tumorigenesis in mice given 7,12-dimethylbenz[a]anthracene.

5.4 Other relevant data

The major urinary metabolites of sodium ortho-phenylphenate are the glucuronide and sulfate conjugates of ortho-phenylphenol and phenylhydroquinone. The capacity of male rats to metabolize sodium ortho-phenylphenate is several times greater than that of females.

Urothelial toxic effects and increased regenerative cell proliferation in the bladder epithelium are induced in rats. Although the mechanism of toxicity is unknown, the higher pH induced by the sodium salt may enhance the toxic effect of sodium ortho-phenylphenate in comparison with that of ortho-phenylphenol.

In a study of rats exposed to ortho-phenylphenol by oral gavage during gestation, the high dose resulted in delayed skeletal maturation of pups but had no effect on their viability, growth or morphological appearance.

No data were available on the genetic and related effects of ortho-phenylphenol and its sodium salt in humans. Mixed results were found in assays with ortho-phenylphenol for genotoxicity in rodents in vivo and in cultured mammalian cells in vitro. It induced gene mutation in mammalian cells in vitro. It was not mutagenic to bacteria or Drosophila but induced aneuploidy in fungi.

5.5 Evaluation

There is inadequate evidence in humans for the carcinogenicity of ortho-phenylphenol and sodium ortho-phenylphenate.

There is limited evidence in experimental animals for the carcinogenicity of ortho-phenylphenol.

There is sufficient evidence in experimental animals for the carcinogenicity of sodium ortho-phenylphenate.

Overall evaluation

ortho-Phenylphenol is not classifiable as to its carcinogenicity to humans (Group 3).

Sodium ortho-phenylphenate is possibly carcinogenic to humans (Group 2B).

For definition of the italicized terms, see Preamble Evaluation.

Previous evaluations: Vol. 30 (1983); Suppl. 7 (1987) (sodium ortho-phenylphenate)

Synonyms ortho-Phenylphenol

Sodium ortho-phenylphenate 

Last updated: 30 September 1999

    See Also:
       Toxicological Abbreviations
       Phenylphenol, ortho- and its Sodium Salt  (IARC Summary & Evaluation, Volume 30, 1983)