Chromate(3-), [3-[(4,5-dihydro-3-methyl-5-oxo-1-phenyl-1H-pyrazol-4-yl)azo]-2-hydroxy-5-nitrobenzenesulfonato(3-)][3-hydroxy-4-[(2-hydroxy-1-naphthalenyl)azo]-7-nitro-1-naphthalenesulfonato(3-)]-, sodium

Short-term toxicity to fish

Description of key information

LC50 (96h): 40 ppm (CL 95 %: 35.9 - 44.7).

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Effect concentration:

40 mg/L

Additional information

The short-term toxicity to fish of Acid Brown 355b (ABr355b) was tested according to the OECD Guideline 203. For the main test the concentrations were selected according to the results of the pretest as: 10, 17.8, 32, 56 and 100 ppm. The concentration of the substance tested has been satisfactorily maintained throughout the test. The LC50 at 96 hours was graphically determined as 41 ppm and calculated as 40 ppm (CL 95 %: 35.9 - 44.7) (Huntsman Textile Effects (Germany) GmbH, 1986).

The test was performed on the ABr355b (EC 280-689-4), trisodium salt: chromate(3-),[3-[(4,5-dihydro-3-methyl-5-oxo-1-phenyl-1H-pyrazol-4-yl)azo]-2-hydroxy-5-nitrobenzenesulfonato(3-)][3-hydroxy-4-[(2-hydroxy-1-naphthalenyl)azo]-7-nitro-1-naphthalenesulfonato(3-)]-, trisodium.

The reference substance under registration is the Acid Brown 355 (ABr355 - EC 284-915 -2), the form which can have a variable number of the sodium atoms. Thus, although it has been appointed a different EC number to the ABr355b trisodium salt form (EC 280-689-4), it can be considered as “included” into the structure variability of the ABr355 (EC 284-915-2). In this context, the use of the experimental data available on the ABr355b (EC 280-689-4), in order to assess the ABr355 (EC 284-915-2), can be considered as not a read across, but an evaluation on one of the possible forms of the ABr355. Furthermore, based on the experience in the manufacture of the ABr355, the most frequent form is the trisodium salt.

A second study is available: the test procedures followed in the study cannot be subsumed under an international testing guideline, nevertheless they are scientifically acceptable. Fish were tested in a static test system for acute toxicity at 96 -h, after an adaptation period. ABr355 was added to the test water without any pretreatment and the concentrations were fixed as follows: 2.15, 4.64, 10.0, 21.5 and 46.4 mg/l (nominal). Symptoms recorded were apathy, narcotic-like state, tumbling (since the test solutions were intensely coloured and cloudy a complete evaluation of the symptoms could not be performed). The maximum concentration tested causing no mortality was 4.64 mg/l, while the minimum concentration tested causing 100 % mortality was 21.50 mg/l; the LD50 was determined to be greater than 10 mg/l, but lower than 22 mg/l (BASF SE, 1991).

According to the CLP Regulation (EC 1272/2008) criteria for the identification of the classification categories for hazardous to the aquatic environment, both studies fixed the short-term effect level on fish between 10 and 100 mg/l.