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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
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
Duration:
72 h
Dose descriptor:
EC10
Effect conc.:
1.8 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Remarks on result:
other:
Remarks:
95 % confidence limit: 1.0 to 2.8 mg/L
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
4.5 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other: yield
Remarks on result:
other:
Remarks:
95 % confidence limit: 4.1 to 4.9 mg/L
Duration:
72 h
Dose descriptor:
EC10
Effect conc.:
0.2 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other: yield
Remarks on result:
other: 95% confidence limit: 0.0 to 0.6mg/L
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
< 2 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other: yield
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 was used to determine the ErC50 and NOEC of Solvent Red 19 T ( 1-({2-methyl-4-[(2-methylphenyl)diazenyl]phenyl}diazenyl)-N-tridecylnaphthalen-2-amine). The results from an analogue substance with the same structure, but where the tridecyl group has been replaced with a 2 -ethyl hexyl group were >100mg/L ( ErC50) and <2mg/L for NOEC. The materials are structural similarity, have similar solubility and QSAR software (EPISUITE ECOSAR) predicts that both materials will show no acute aquatic toxicity at saturation. The 2 hour ErC50 was predicted to be >100 mg/L and the 72 hour NOEC was predicted to be <2 mg/L.

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 for freshwater algae:
100 mg/L
EC10 or NOEC for freshwater algae:
1.8 mg/L

Additional information

A read across approach was used to determine the ErC50 and NOEC of Solvent Red 19 T ( 1-({2-methyl-4-[(2-methylphenyl)diazenyl]phenyl}diazenyl)-N-tridecylnaphthalen-2-amine). The results from an analogue substance with the same structure, but where the tridecyl group has been replaced with a 2 -ethyl hexyl group were >100mg/L ( ErC50) and <2mg/L for NOEC. The materials are structural similarity, have similar solubility and QSAR software (EPISUITE ECOSAR) predicts that both materials will show no acute aquatic toxicity at saturation. The 2 hour ErC50 was predicted to be >100 mg/L and the 72 hour NOEC was predicted to be <2 mg/L.