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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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Reference
Endpoint:
toxicity to aquatic algae and cyanobacteria
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Justification for type of information:
REPORTING FORMAT FOR THE ANALOGUE APPROACH : Please see attached Read Across supporting document in Section 13 which includes the following:
1. HYPOTHESIS FOR THE ANALOGUE APPROACH
2. SOURCE AND TARGET CHEMICAL(S) (INCLUDING INFORMATION ON PURITY AND IMPURITIES)
3. ANALOGUE APPROACH JUSTIFICATION
4. DATA MATRIX
Reason / purpose:
read-across source
Related information:
Composition 1
Test material information:
Composition 1
Key result
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
> 100 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Key result
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
< 2 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Conclusions:
Based on read across to an analogue substance, the 72 hour ErC50 was predicted to be >100 mg/L and the 72 hour NOEC was predicted to be <2 mg/L.
Executive summary:

A read across approach to an analogue substance was used to predict the Acute toxicity to Daphnia. The source and the target substance are Solvent Red 19E (N-(2-ethylhexyl)-1-[[2-methyl-4-[(2-methylphenyl)azo]phenyl]azo]naphthalen-2-amine) and Solvent Red 500 (N-(2-ethylhexyl)-1-[[3-methyl-4-[(3-ethylphenyl)azo]phenyl]azo]naphthalen-2-amine).

 

They have the same molecular weight, and the same structure, differing only in the position of the methyl groups on the aromatic rings.

Using QSAR tools, both materials give the same predicted outputs for both water solubility and Aquatic Toxicity. 

Experimental data for both materials also confirms that they are both insoluble. The target substance Solvent Red 500 is therefore concluded to have the same aquatic toxicity properties as Solvent Red 19E. See the Read Across justification document for further information.

Description of key information

Based on read across to an analogue substance, the 72 hour ErC50 was predicted to be >100 mg/L and the 72 hour NOEC was predicted to be <2 mg/L.

Key value for chemical safety assessment

EC50/LC50 for freshwater algae:
100 mg/L
EC10, LC10 or NOEC for freshwater algae:
1.8 mg/L

Additional information