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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Administrative data

Key value for chemical safety assessment

Additional information

The germ cell mutagenicity potential of the target substance sodium 4-hydroxyphenolate (EC 701-006-2) was determined by read-across from the harmonized classification for hydroquinone (EC 204-617-8). The target molecule, Sodium 4-hydroxyphenolate has the same molecular structure as the free phenol hydroquinone, with the exception that one proton on one of the phenolic group is replaced by sodium. In aqueous solution, both substances have a pH-dependent equilibrium, which is governed by the pKa value of the phenolic hydrogens (ca. 9.95 in water). In biological systems, the transport, the mode of action, the metabolism, and the metabolic fate for the source and the target chemical are likely to be identical. Upon oral administration, the sodium 4-hydroxyphenolate first mixes with the acidic medium in the stomach. The pH of gastric fluid varies widely with the species and the nutritional status. Values for humans are of 1.7 (1.4 - 2.1) in the fasted state, and 5.0 (4.3 - 5.4) upon food intake. For rats, pH in the median anterior portion of the stomach is reported to be 5.0, in the median posterior portion 3.0, without reference to feeding state. Despite the variations, it is concluded that in gavage applications the test substance is always exposed to a pH around or below 2, which converts the sodium salt to the free phenol, since this route is normally applied to fasted animals. From this point on, the source chemical and target chemical will be indistinguishable. As a conclusion, the mutagenicity potential of sodium 4-hydroxyphenolate is estimated to be similar to that of hydroquinone.


Short description of key information:
The mutagenicity potential of the target substance sodium 4-hydroxyphenolate (EC 701-006-2) was determined by read-across from the harmonized classification for hydroquinone (EC 204-617-8).

Endpoint Conclusion: No study available

Justification for classification or non-classification

Sodium 4-hydroxyphenolate (EC 701-006-2) is classified as a germ cell mutagen category 2 based on a read-across from the harmonized classification for hydroquinone (EC 204-617-8).