Reaction mass of tetrasodium [μ-[[4,4'-[(3,3'-dihydroxy[1,1'-biphenyl]-4,4'-diyl)bis(azo)]bis[3-hydroxynaphthalene-2,7-disulphonato]](8-)]]dicuprate(4-) and hydrogen [[4,4'-[(3,3'-dihydroxy[1,1'-biphenyl]-4,4'-diyl)bis(azo)]bis[3-hydroxynaphthalene-2,7-disulphonato]](8-)]]dicuprate(4-)

Endpoint summary

Additional information

Despite the alert on benzidine functional group contained in the molecule, the substance has been evaluated in a weight of evidence based on symilar substances of the same benzidine-congener-based dyes copper complex and the fact that under reduction, no release of benzidine has been measured over 10 ppm.

The considered similar substances are:

1) The non-phase in substance Blue GS 1259 R5, EC 407-230-4, CAS 126637-70-5, dilithium disodium (5,5'-diamino-(μ-4,4'-dihydroxy-1:2-κ-2,O4,O4',-3,3'-[3,3'-dihydroxy-1:2-κ-2-O3,O3'-biphenyl-4,4'-ylenebisazo-1:2-(N3,N4-η:N3',N4'-η)]-dinaphthalene-2,7 -disulfonato(8)))dicuprate(2-). The Registrant has not yet letter of access to the study in the scope of Registration, but received enough information from the data owner to refer to this study in the framework of answeering to the ECHA common screening. For this substance a bacteriar reverrse mutation test according to OECD 471 has been performed in GLP in 1990 with negative results with and without methabolic activation.On the same substance an in vivo Mammalian Bone Marrow Chromosome Aberration Test OECD 475 has been performed as well with negative results.

2) C.I Direct Blue 218, EC 249-008-8 , CAS 28407-37-6, tetrasodium;(3E)-5-amino-3-[[4-[4-[(2E)-2-(8-amino-1-oxo-3,6-disulfonatonaphthalen-2-ylidene)hydrazinyl]-3-hydroxyphenyl]-2-hydroxyphenyl]hydrazinylidene]-4-oxonaphthalene-2,7-disulfonate;copper, was not mutagenic in Salmonella typhimurium strains TA98, TA100, TA1535, or TA1537 tested with and without exogenous metabolic activation (S9). It was also tested in a modified Salmonella test protocol which employed reductive metabolism supplied by flavin mononucleotide or rat cecal bacteria, followed by oxidative metabolism; results of this test using strain TA1538 were also negative. C.I. Direct Blue 218 induced a small but significant increase in sister chromatid exchanges in Chinese hamster ovary cells at the highest dose tested without S9. No increase in chromosomal aberrations were observed in Chinese hamster ovary cells with or without S9.

[ETAD; Initial Submission: NTP Technical Report on the Toxicology and Carcinogenesis Studies of C.I. direct Blue 218 in F344 Rats and B6C3F1 Mice with Cover Letter Dated 12/21/92; 12/01/92; EPA Doc. No. 88-930000102; Fiche No. OTS0556439] Based on the above evidences, the substance can not be considered as mutagen. Mutagenicity studies provided evidence that the benzidine- and benzidine congener- derived dyes require reductive metabolism before they are mutagenic. All soluble dyes tested, with the exception of Direct Blue 218 (copper chelated), produced frameshift mutations in Salmonella when tested under conditions that fostered reduction of the azo bonds. The azo linkages in Direct Blue 218 also appeared to be reduced by the NADP/FMN-fortified rodent liver preparations and by the cecal extract, as judged by the change in visible color intensity, but the resulting product was not mutagenic. This may indicate that the reduction of this dye does not release the free amine, but a copper complex of this amine with the chromophore or to 3,3'- dihydroxybenzidine. [Summary of the National Toxicology Program Benzidine Dye Initiative Daniel L. Morgan, 'June K. Dunnick Thomas Goehl' Michael R Jokinen1 H. B. Matthews' Errol Zeiger) and John H. Mennear Volume 102, Supplement2, June 1994][Reid TM, Morton KC, Wang CY, King CM. Mutagenicity of azo dyes following metabolism by different reductive/oxidative systems. Environ Mutagen 6:705-717(1984).]

Justification for selection of genetic toxicity endpoint
The assessmento for genotoxicity has been performed on similar substances, of the same benzidine-congener-based dyes. Despite the alert on benzidine potential functional group, the substance, together with the similar ones we took into considerations, have the benzinic group bound to the copper metal, in a way that preserve his release, methabolismus or reactivity. This is also supported from the fact that no benzidine is released over 10 ppm after chemical reduction and the related test is attached in the analytical identification IUCLID section 1.4

Short description of key information:
Non genotoxic

Endpoint Conclusion: No adverse effect observed (negative)

Justification for classification or non-classification

A mutation means a permanent change in the amount or structure of the genetic material in a cell. The term ‘mutation’ applies both to heritable genetic changes that may be manifested at the phenotypic level and to the underlying DNA modifications when known (including specific base pair changes and chromosomal translocations). The term ‘mutagenic’ and ‘mutagen’ will be used for agents giving rise to an increased occurrence of mutations in populations of cells and/or organisms. The more general terms ‘genotoxic’ and ‘genotoxicity’ apply to agents or processes which alter the structure, information content, or segregation of DNA, including those which cause DNA damage by interfering with normal replication processes, or which in a non- physiological manner (temporarily) alter its replication. Genotoxicity test results are usually taken as indicators for mutagenic effects.

Data on similar substances are available for classification of Direct Blue 080:1, therefore no classification for genetic toxicity is warranted under Regulation 1272/2008.