Amines, C12-14-tert-alkyl, compds. with 1-[2-[5-(1,1-dimethylpropyl)-2-hydroxy-3-nitrophenyl]diazenyl]-2-naphthalenol 1-[2-[2-hydroxy-4(or 5)-nitrophenyl]diazenyl]-2-naphthalenol chromium complexes

Endpoint summary

Description of key information

Based on the blackish discoloration of the whole body, at least the chromophore of the black dye is taken up by in distributed throughout the body. Upon cessation of treatment, the discoloration disappears with time.

Key value for chemical safety assessment

Bioaccumulation potential:

low bioaccumulation potential

Additional information

No specific experimental toxicokinetic data is available. The product is a UVCB mixture of anionic chrome-azo complexes that form salts with a UVCB mixture of highly branched N-cationic trialkylamines. The molecular weights range between 851.53 - 949.67 g/mol.

Determination of the log Pow with the HPLC-method (OECD 117) showed five signals corresponding to log Pow values between 2.29 and 3.66. As these values are below 4.5, they do not give rise of concern for bioaccumulation.

Based on the results of the water solubility determination, non-coloured components (absorption at 226 nm) with a sum water solubility of 23 mg/L are present. The coloured components (absorption at 574 nm) are poorly soluble in water at neutral pH (< 0.5 mg/L); they are soluble in fat (43 g/kg fat).

The stability in the highly acidic environment of the stomach is unknown. Considering that after oral dosing of rats, the rat body shows a dose-dependent blackish discoloration, the chromophore should remain intact. During the study, rat feces showed a black coloration which is considered to be related to the colour of the test substance.

Repeated oral intake of the test substance at 1000 mg/kg/ bw/day in young animals resulted in reversible purple or blue skin/fur as well as in bluish discolouration of the pancreas and testes. In the absence of any microscopic correlates and given that the test article is a dye stuff, these discolourations were concluded to be due to passive staining and not a toxicological response. The bluish discoloration of the pancreas and testes was observed in three of five males after 28 days. At the end of the recovery period, one male showed bluish discoloration in testes. For females, one of five and none of five animals showed bluish discoloration of the pancreas at the end of the treatment period and after recover, respectively. No discoloration was observed at the doses of 200 and 50 mg/kg bw.

Apart from the discoloration, changes in clinical chemistry were observed at 200 and 1000 mg/kg bw. These do not give a clear picture of target organs and they were reversible within the 14 day recovery period. For details it is referred to the section describing repeated dose toxicity.

 

In contrast to the absence of toxicity observed in the repeated dose toxicity study (OECD 407), significant toxicity (ie mortality at 1000 mg/kg bw) is observed in parental animals in the screening study for reproductive toxicity (OECD 421). The only difference between those studies were the age and accordingly the body weights of the animals. During the OECD 407 study, rats are young and double their body weights between the beginning and the end of the study. For the OECD 421 study, the initial body weight of the rats roughly corresponds to that at the end of the OECD 407 study. For equal doses in regard to mg/kg bw, the total amount of the test material is twice as high in the OECD 421 study.

For older and heavier rats as used in the screening study for reproductive toxicity, dark discoloration of blood samples was reported indicating transport via the blood.

The discoloration pattern indicates uptake after ingestion and elmination via the bile at overload doses. Elimination of the intact dye via the urine is unlikely as this should have resulted in dark discoloration, which was not observed.

Upon cessation of treatment, the discoloration of the animals disappears (BASF 2012): The black discoloration of rats treated with 1000 mg/kg bw for 18 days completely disappeared within a a post-dosing period of 24 days.

Overall, it is concluded that the substance is unlikely to have a potential for bioaccumulation.

Dermal absorption

A molecular weight of > 500 g/mol is generally considered unfavourable for skin penetration. This criterium is clearly fulfilled for the coloured components

(851.53 - 949.67 g/mol)

. The log Pow values are less than 4, therefore the default assumption of 10% permeability cannot be applied. Inhalation The vapour pressure of the substance is negligible, therefore exposure via the gas phase is not relevant. Inhalation to mist or fine dusts is expected to result in particle deposition in the respiratory tract. Systemic uptake from there is at least possible after mucociliary clearance to the stomach.