Trisodium bis[3-[(4,5-dihydro-3-methyl-5-oxo-1-phenyl-1H-pyrazol-4-yl)azo]-2-hydroxy-5-nitrobenzenesulphonato(3-)]chromate(3-)

Endpoint summary

Description of key information

Short-term toxicity to aquatic invertebrates

EC50 (48h) = 6.11 mg/l

Toxicity to aquatic plants other than algae

ErC50 > 100 mg/l

Additional information

No studies on the "Aquatic toxicity" are available for the substance in itself nevertheless, studies were conducted with an analogue molecule (Similar Substance 01). Further information on the adequacy of the Read Across approach is reported in the Read Across justification attached to section 13.

Short-term toxicity to aquatic invertebrates

A GLP compliant study was carried out in accordance with OECD Guidelines for the testing of chemicals, section 2 Number 202 “Daphnia Sp., Acute Immobilisation Test”, Adopted 13th April 2004 to assess the effect of the test substance. Based on the results of a range finding experiment the test concentrations were set as follows: 1, 1.5, 2.3, 3.4, 5.1, 7.6 and 11.4 mg/l. Four replicates each containing 10 daphnids were held for each test concentration and a control group. Analysis of the test preparations at 0 and 48 hours showed measured concentrations to be near nominal and so the results are based on nominal concentrations only.   Based on the test results, the EC50 of the test substance in Daphnia magna observed for a period of 48 hours was calculated as 6.11 mg/l. The no observed effect concentration (NOEC) was calculated as 3.4 mg/l and the low observed effect concentration (LOEC) was calculated as 5.1 mg/l.

Toxicity to aquatic plants other than algae

In a GLP-compliant OECD 221 guideline study Lemna gibba (Duckweed) exposed to the test item recorded:

ErC50 based upon the frond numbers observed for a period of ‘7’ days for Lemna gibba was found to be > 100 mg/L.

All fronds were found normal and healthy in all replicates of control and test concentration after 7 days leading to the end point being determined as ErC50 > 100mg/l and EyC50 > 100mg/l.

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 availableand 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

Based on the above results, the Daphnia study provides the lowest toxicity endpoint and therefore will be used for Classification as Aquatic Chronic 2 (H411).