Sodium [3-hydroxy-4-[(1-hydroxy-8-sulpho-2-naphthyl)azo]naphthalene-1-sulphonato(4-)]chromate(1-)

Endpoint summary

Description of key information

Short-term toxicity to fish: LC50(48h) = 450 mg/l

Short-term toxicity to invertebrates: EC50 (48h) = 4.40 mg/l

Toxicity to aquatic plants: ErC50(7d): 21.12 mg/l

Toxicity to microorganisms BST > 300 mg/l

Additional information

The assessment is based on information gathered by studies conducted in order to evaluate the acute toxicity to fish, invertebrates, aquatic plants and microorganisms. The studies on Daphnia magna and Lemna Gibba are performed on the Similar Substance 01 and considered for the chemical safety assessment due to the similarity between the similar substance and the target substance. The complete evaluation and justification of the read across aprroach is attached at section 13..

Acute administration to fish:

The short term toxicity to fish was evaluated according to the CIBA GEIGY internal method 11. Eight Salmo gairdneri was tested at concentration of 100, 200 and 1000 mg/l. The substance shows a LC50(48h) = 450 mg/l

Acute toxicity testing on invertebrates:

Acute Immobilization Toxicity Study in Daphnia magna was conducted on Similar Substance 01 in accordance with OECD guideline 202. Based on the results of the range finding experiment, main experiment was conducted with the following concentrations: 0.30, 0.60, 1.20, 2.40, 4.80, 9.60 and 19.20 mg/l.

NOEC (48h) = 0.60 mg/l LOEC (48h) = 1.20 mg/l

EC50 (48h) = 4.40 mg/l

Toxicity to aquatic plants other than algae:

Lemna gibba (Duckweed) were exposed to Similar Substance 01 at test concentration of 100 mg/l. Three replicates for each test concentration and six replicates for control were maintained.

After exposure, Lemna gibba was observed for frond count on days ‘3’, ‘5’ and ‘7’. Dry weight of the fronds were recorded at start (pre-culture representative samples) and at the end of the test. Fronds were observed for their appearance on days ‘3’, ‘5’ and ‘7’. All fronds were found normal and healthy in all replicates of control and test concentration except 51.54 mg/L where necrosis observed on day ‘5’ and in addition to necrosis, root filaments were turned blue in 10.65, 23.43 and 51.54 mng/l concentrations on day ‘7’.

The doubling time (Td) of frond number in the control group was calculated as 1.608 day^-1.

ErC50(frond numbers) 21.12 mg/l

ErC50(frond dry weight) 21.67 mg/l

EyC50(frond numbers) 9.55 mg/l

EyC50(frond dry weight) 8.69 mg/l

NOEC = 2.2 mg/l

LOEC= 4.84 mg/l

Toxicity to microorganisms

The substance has been tested for bacteria growth inhibition according to internal method 58. The substance shows a BST> 300 mg/l.

Justification for classification or non-classification

As observed from these results the substance does not shows signs of toxicity from one of the three trophic levels. The values from toxicity to fish is above the trigger values for classification according to the CLP Regulation (EC n. 1272/2008).

The toxicity value for Daphnia magna (the most sensitive specie) are:

NOEC 48h = 0.60 mg/l

EC50 48h = 4.4 mg/l

EC100 48h = 19.20 mg/l.

The toxicity value for Lemna Gibba (Duckweed) are:

ErC50(frond numbers) 21.12 mg/l

ErC50(frond dry weight) 21.67 mg/l

EyC50(frond numbers) 9.55 mg/l

EyC50(frond dry weight) 8.69 mg/l

NOEC = 2.2 mg/l

LOEC= 4.84 mg/l

The values are below the limit for avoiding the classification (1 mg/l < Category Chronic 2 ≤ 10 mg/l.

Based on values reported above the classification as Aquatic Category Chronic 2 (H411: Toxic to aquatic life with long lasting effects) is proposed according to the CLP Regulation (EC n. 1272/2008).