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EC number: 235-115-7 | CAS number: 12069-89-5
Short-term toxicity to fish
Administrative data
Link to relevant study record(s)
Description of key information
No mortality could be observed for Danio rerio (zebra fish) when exposed to Mo2C at nominal concentrations of 100 mg/L for 96 h. Accordingly, the 96-h LC50 was >100 mg/L (nominal concentration), and the 96-h LC0 was ≥ 100 mg/L. For Oncorhynchus mykiss mortality could be observed with a corresponding 96-h-LC50 value of 7600 mg/L (test substance: disodium molybdate dihydrate). Therefore, molybdenum released from Mo2C does not exert significant toxicity to fish.
Key value for chemical safety assessment
Fresh water fish
Fresh water fish
- Effect concentration:
- 7 600 mg/L
Additional information
The 96 h acute toxicity of Mo2C to Danio rerio (zebra fish) was studied under semi-static conditions according to OECD guideline 203. Fish were exposed to Mo2C at a concentration of 100 mg/L (nominal concentration). Throughout the study period no mortality and no other signs of toxicity could be observed. Accordingly, the 96-h LC50 was >100 mg/L (nominal concentration), and the 96-h LC0 was ≥ 100 mg/L.
Another study was performed using sodium molybdate dihydrate in a semi-static test on the test species Oncorhynchus mykiss according to OECD guideline 203 and under GLP. After 96 h, the test item exhibited an LC50 of ca. 7600 mg/L. Further observations of adverse effects included increased pigmentation, lethargy, swimming at surface, loss of equilibrium, lying on bottom of aquarium, exophthalmia, loss of pigmentation and haemorrhaging at the base of the pelvic fins. Available data from sodium molybdate dihydrate are appropriate to be used for the read-across approach. Due to lower water solubility for dimolybdenum carbide 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. The combined information from both studies demonstrates that molybdenum released from Mo2C does not exert significant toxicity to fish. The mortality observed in the sodium molybdate dihydrate study occurred at excessive test concentrations that are not relevant for hazard assessment.
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