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Short-term toxicity to fish

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Description of key information

The 96-h LC50 of Rosamusk is 4.2 mg/L based on a read across from CP Formate, which was tested in a study in accordance with OECD TG 203 with an obtained 96-h LC50 of 8 mg/L. Rosamusk short-term toxicity to fish is converted from the CP Formate LC50 based on the difference between the measured log Kow values of 4.9 and 4, respectively, and the MW of 196 and 184 g/mol, respectively. The value is used for supporting information only.

Key value for chemical safety assessment

Fresh water fish

Fresh water fish
Effect concentration:
4.2 mg/L

Additional information

No experimental data is available for Rosamusk, therefore read-across is performed to the close structural analogue CP Formate.

CP Formate acute Fish toxicity

An OECD TG 203 guideline study in compliance with GLP with carp (Cyprinus carpio) is available for the test substance. Fish (7/dose) were exposed to nominal concentrations ranging from 4.6 to 100 mg/L under semi-static conditions for 96 hours. Since the test substance was volatile, the study was performed in air-tight vessels and the media were not aerated. Test substance concentrations were analytically determined and expressed as mathematical means of the concentrations of the test substance measured in the samples taken during the first (t = 0 - 24 h) and the last refreshment period (t = 72 - 96 h). The average exposure concentrations were calculated to correspond with 2.6, 4.9, 13, 34 and 39 mg/L for the WAFs prepared at 4.6, 10, 22, 46 and 100 mg/L, respectively. The test substance induced no lethal effects in carp at or below a WAF prepared at a loading rate of 10 mg/L with an average exposure concentration of 4.9 mg/L (NOEC). At a concentration of 13 mg/L, 100% mortality was observed within 24h after exposure. At the two highest concentrations, 100% mortality was observed within 3h after exposure. No clinical abnormalities were seen in the control and the lowest concentration tested. At an average concentration of 4.9 mg/L, all fish from 3-48 h showed discolouration and hypoactive swimming and in addition occasional tottering after 72-96 h. From an average concentration of 13 mg/L fish showed immobility and loss of righting reflex within 3 h after exposure. The study met the acceptability criteria prescribed by the protocol and was considered valid. The 96-h LC50 value is 8.0 mg/L (95% C.L. is 4.9 -13 mg/L).

Rosamusk acute fish toxicity (read across from CP Formate)

Rosamusk has a higher log Kow and a slightly lower water solubility, compared to CP Formate (log Kow is 4.9 and 4.0 and water solubility is 12.6 and 26.1 mg/L, respectively), which can be expected from the additional methyl group in Rosamusk. In view of the difference in log Kow > 0.5 this needs to be accounted for. First the conversion from mg/L to Mmol is needed, which then need to be log transformed because the toxicity is related to the log Kow and not to Kow. The calculation equation is: Log (x mg/L source / mol weight source)*(log Kow target / Log Kow source)*10^*mol weight target = mg/L target. The 96-h LC50 of Rosamusk is 4.2 mg/L based on a read across from CP Formate, based on measured log Kow of 4.9 and 4, respectively, and a MW of 196 and 184, respectively.