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Ecotoxicological information

Short-term toxicity to aquatic invertebrates

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Reference
Endpoint:
short-term toxicity to aquatic invertebrates
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Justification for type of information:
For details and justification of read-across please refer to the attached report in section 13 of IUCLID.
Reason / purpose:
read-across source
Key result
Duration:
48 h
Dose descriptor:
EC50
Effect conc.:
ca. 330 mg/L
Nominal / measured:
nominal
Conc. based on:
dissolved
Basis for effect:
mobility
Remarks on result:
other: 95 % CL =250-440 mg/L
Duration:
24 h
Dose descriptor:
EC50
Effect conc.:
ca. 3 100 mg/L
Nominal / measured:
nominal
Conc. based on:
dissolved
Basis for effect:
mobility
Remarks on result:
other: 95 % CL =2500-3900 mg/L
Duration:
48 h
Dose descriptor:
NOEC
Effect conc.:
ca. 100 mg/L
Nominal / measured:
nominal
Conc. based on:
dissolved
Basis for effect:
mobility
Duration:
24 h
Dose descriptor:
NOEC
Effect conc.:
ca. 1 000 mg/L
Nominal / measured:
nominal
Conc. based on:
dissolved
Basis for effect:
mobility
Validity criteria fulfilled:
yes
Conclusions:
The EC50 value of sodium molybdate dihydrate to Daphnia magna was found to be 3100 mg/L (24 h) and 330 mg/L (48 h).
This information is used in a read-across approach in the assessment of molybdenum disilicide.
Executive summary:

The 48-hr-acute toxicity of sodium molybdate dihydrate to Daphnia magna was studied under static conditions. Daphnids were exposed to control and test chemical at nominal concentrations of 100, 180, 320, 560, 1000, 1800, 3200, 5600 and 10000 mg/L for 48 hr. Mortality/immobilisation and sub-lethal effects were observed daily. The 48-hour EC50 was 330 mg/L. The 48-hr NOEC based on immobilisation was 100 mg/L. Sub-lethal effects were not reported.

Based on the results of this study, sodium molybdate dihydrate would not be classified for aquatic toxicity in accordance with the CLP classification system (Regulation (EC) No 1272/2008).

This study is classified as acceptable and satisfies the guideline requirements for an acute toxicity study with freshwater invertebrates.

Results Synopsis

Test organism age: Neonates

Test type: Static

EC50: 330 mg/L (95 % C.I.: 250 to 440 mg/L)

NOEC: 100 mg/L

Endpoint(s) effected: Immobilitsation

This information is used in a read-across approach in the assessment of the target substance.

For details and justification of read-across please refer to the attached report in section 13 of IUCLID.

Description of key information

The EC50 value of Sodium molybdate dihydrate to Daphnia magna was found to be 330 mg/L (48 h). 

Key value for chemical safety assessment

EC50/LC50 for freshwater invertebrates:
330 mg/L

Additional information

The EC50 value of Sodium molybdate dihydrate to Daphnia magna was found to be 330 mg/L (48 h). Available data from Sodium molybdate dihydrate are appropriate to be used for the read-across approach. Due to lower water solubility for Molybdenum disilicide compared to Sodium molybdate dihydrate the resulting toxicity is also expected to be lower. Hence, the read across to the substance Sodium molybdate dihydrate is sufficiently protective.