3-[[2-(acetyloxy)ethyl][4-[(4-nitrophenyl)azo]phenyl]amino]propiononitrile

Endpoint summary

Description of key information

Short-term toxicity to aquatic invertebrates

EC50 (48 h) = 18.6 mg/l (nominal concentration)

Toxicity to aquatic algae and cyanobacteria

ErC50> 100 mg/l (loading rate value)

EyC50 > 100 mg/l (loading rate value)

Additional information

Aquatic toxicity of target substance was assessed based on a read across approach, using available data on Similar Substance 01. Details on the read across are reported in section 13.

Both target substance and read across substance are not ready biodegradable and have a low solubility, below 20 mg/l in water.

Short-term toxicity to aquatic invertebrates

Similar Substance 01 was tested for acute toxicity to daphnia magna in a 48 -hour static test according to OECD guideline 202.

Nominal concentrations tested were 100 %, 50 %, 25 %, 12.5 %, 6.25 % of a saturated solution with nominal loading of 100 mg/l. Measured concentrations 0 -hour and 48 -hour after start of exposure were below the lowest calibration level, thus nominal value were used. At nominal concentration of 25 mg/l, 18/20 were found to be immobile; at higher concentrations all daphnids were immobile.

Based on nominal concentrations, the EC50 value was calculated as 18.6 mg/l after 48 hours.

Toxicity to aquatic algae and cyanobacteria

Similar Substance 01 was tested on toxicity to aquatic algae and cyanobacteria in a 72 -hour static test according to OECD guideline 201.

A saturated solution with a nominal loading of 100 mg test substance/l was prepared and undissolved particles were removed by membrane filtration. Components of dilution water were added to the saturated solution. Concentrations used in the test were 6.25 - 12.5 - 25.0 - 50.0 - 100 % of the saturated solution. Three replicates were tested for each concentration and six replicates for the control. Test media were clear throughout the test period. Analytical monitoring of test solutions was done via HPLC‑DAD at 0 h and recovery rates were found to be below the lowest calibration level (LCL). Therefore, all effect values were referred to nominal loading levels. After 72 h, growth rate inhibition at the highest loading level was only 6 % (not significant) and yield inhibition was 28 %. Thus,

- growth rate: ErC50 (72h) > 100 % (i.e. 100 mg/l nominal loading).

- yield: EyC50 (72h) > 100 % (i.e. 100 mg/l nominal loading).

Justification for classification or non-classification

According to the CLP Regulation (EC 1272/2008), the threshold of classification of a substance for acute aquatic toxicity is 1 mg/l. This limit is compared with LC50 (96h) for fish, EC50 (48 h) for daphnia and EC50 (72 - 96 h) for algae or aquatic plants.

As for chronic toxicity, in case of lack of chronic data, the toxic potential is identified by appropriate combinations of acute toxicity data and lack of biodegradability. The threshold of classification is 100 mg/l.

In case of poorly soluble substances, the threshold for classification is identified as the solubility limit of the substance.

Based on EC50 values obtained, no classification for acute toxicity was applied; based on EC50 (48h) of 18.6 mg/l for immobilisation effects in daphnids, the substance is classified as Aquatic Chronic Toxicity 3 for chronic toxicity according to the CLP Regulation (EC 1272/2008).