Reaction products of diazotised 4'-aminoazobenzene-4-sulphonic acid, coupled with resorcinol and diazotised sodium 4-aminobenzenesulfonate, sodium salts

Endpoint summary

Description of key information

Short-term toxicity to aquatic invertebrates:

EC50 (Daphnia magna, 48 h) > 100 mg/L

Toxicity to aquatic plant other than algae:

ErC50 (Lemna minor, 7d) 100 - 1000 mg/L

Additional information

Invertebrate acute toxicity

The aquatic toxicity against Daphnia magna of the substance was investigated using a specific QSAR model, developed to predict the acute oral toxicity for dyes. The existing QSAR models have strong limitations to predictionic complex structures as the organic dyes are, and consequently they provide unreliable results. The QSAR modelling was developed in accordance with the OECD principles (details in the documentationattached).

Based on the estimation, the substance is expected to have no concern foraquatic toxicity against Daphnia magna. The estimation resulted to be in the applicability domain of the model.

Thus, the substance can be considered as not classified foraquatic toxicity against Daphnia magna.

 

In order to confirm the results obtained by the QSAR prediction, the investigations performed on an analogue substance (Similar Substance 01) are used as support of the prediction. Justification for Read Across is given in Section 13 of IUCLID.

Acute toxicity to Daphnia magna was determined following OECD guideline 202. Toxic effects were evaluated in terms of mobility, using nominal test concentrations of 95, 171, 309, 556 and 1000 mg test substance /l and a control. Actual concentrations in test media were also measured.

In test media, measured concentrations of test substance only amounted to 29.2 - 41.7 % of nominal values. These low recovery rates were probably due to precipitation of test substance, which was seen in test media of all test concentrations during test duration and also in samples taken for analytical measurements. Since measured concentration of stock solution was 102.4 % of nominal value, results were reported as nominal concentrations of test substance.

Up to the highest concentration tested of 1000 mg test substance/l, no toxic effect on Daphnia magna was observed. Therefore, after 48 hours of exposure:

EC0 = 1000 mg/l and EC50 > 1000 mg/l.

Aquatic plant other than algae toxicity

The following data was obtained for the Similar Substance 02. It is expected that the Target substance will present similar effect levels to aquatic plants other than algae. Justification for Read Across is given in Section 13 of IUCLID.

The inhibitory effects of the test item to Lemna minor were investigated over a period of 7 days, according to the OECD Guideline 221 (2006). The test was performed at concentrations of 10, 100 and 1000 mg/l of the active ingredient. The determination of the effect concentrations was based on the nominal concentrations, assuming the test item to be stable in water for the whole test period.

Based on the data observed with respect to growth rate and yield for the endpoint frond numbers, the ErC50 and the EyC50 were found to be 100 -1000 mg/l and about 100 mg/l based on active ingredient, respectively. The no-observed-effect concentrations to Lemna minor with respect to growth rate (NOErC) and yield (NOEyC) for the endpoint frond numbers were 10 mg/l active ingredient, as determined by Dunnett's test.

Justification for classification or non-classification

According to the CLP Regulation (EC n. 1272/2008), Part 4: Environmental Hazards, the substances can be classified for hazardous to the aquatic environment when the following criteria are met:

A )Acute (short-term) aquatic hazard Category Acute 1: 96 hr LC 50 (for fish) and/or 48 hr EC 50 (for crustacea) and/or 72 or 96 hr ErC 50 (for algae or other aquatic plants) ≤ 1 mg/l.

B) Long-term aquatic hazard (iii) Substances for which adequate chronic toxicity data are not available and the substance is not rapidly degradable and/or the experimentally determined BCF ≥ 500 (or, if absent, the log K ow ≥ 4).

Category Chronic 1: 96 hr LC 50 (for fish) and/or 48 hr EC 50 (for crustacea) and/or 72 or 96 hr ErC 50 (for algae or other aquatic plants) ≤ 1 mg/l

Category Chronic 2: 96 hr LC 50 (for fish) and/or 48 hr EC 50 (for crustacea) and/or 72 or 96 hr ErC 50 (for algae or other aquatic plants)> 1 to ≤10 mg/l

Category Chronic 3:96 hr LC 50 (for fish) and/or 48 hr EC 50 (for crustacea) and/or 72 or 96 hr ErC 50 (for algae or other aquatic plants) > 10 to ≤ 100 mg/l.

 

The substance is not rapidly degradable and the available data fixed the effect levels to Daphnia magna and Lemna minor that do meet the criteria related to the above mentioned hazard categories. Therefore, the substance is not classified for Aquatic toxicity according to the CLP Regulation (EC 1272/2008).