Reaction mass of N-(4-(bis(4-(methylamino)phenyl)methylene)cyclohexa-2,5-dienylidene)-N-methylmethanaminium acetate and [4-[[4-(dimethylamino)phenyl][4-(methylamino)phenyl]methylene]cyclohexa-2,5-dien-1-ylidene]dimethylammonium acetate and [4-[bis[4-(dimethylamino)phenyl]methylene]-2,5-cyclohexadien-1-ylidene]dimethylammonium acetate

Endpoint summary

Description of key information

The substance is produced and put on the market only in acetic aqueous solution and cannot be isolated in a solid powder form. Solvent removal in liquid basic dyes is not always feasible and it ends with a composition containing the substance and some acetic acid crystals, that is not representative of the chemistry of the basic dye and that will have a substantial influence on the general properties of the substance. Moreover, it has been experienced that triphenylmethane basic dye after dehydration produce the reduced (neutral) insoluble form, losing their cationic property. Therefore it is proposed that the properties of the substance are assessed by read across from similar substance. In particular for biodegradation properties, analogue sbstance 3 was tested for ready biodegradation following OECD 301E (BASF, 1982) showing no ready biodegradation properties. Since the acetate portion is readly biodegradable, the cationic part, the dimethylviolet-cation with a triarylmethane structure, has the responsability for the non biodegradability of the substance. Triarylmethanes are known to be poorly biodegradable: in the BASF study a DOC removal of 10 - 20% DOC in 28 days was observed. Studies on the biodegradation of other triarylmethane dyes (Cha et al. 2001, Yatome et al. 1993) indicated that only minor parts of the C-backbone are susceptible to biodegradation.

Based on the read across considerations, the same results apply to Basic Violet 1 Acetate and the substance can be considered as non ready biodegradable and consequently persistent.