Propanoic acid, 2-hydroxy-, (1R,2S,5R)-5-methyl-2-(1-methylethyl)cyclohexyl ester, (2S)-

Short-term toxicity to aquatic invertebrates

Description of key information

The substance menthyl lactate showed low acute toxicity to freshwater invertebrates (Daphnia magna). The EC50 based on immobilisation was between 125 mg/L (nominal, EC0) and 271.06 mg/L (geometric mean of measured concentration over 48 hours, EC100).

Additional information

A study on the acute toxicity of menthyl lactate to freshwater invertebrates (Daphnia magna) was performed under static conditions over a period of 48 hours. The suitability of the test system was confirmed in a study with the positive reference substance potassium dichromate. The substance was undergoing relatively rapid hydrolysis under the test conditions. The main metabolite of hydrolysis was L-menthol. Due to the observed hydrolysis of the test substance, nominal concentrations were confirmed by gas chromatography analysis at the start of the experiment and at 24-hour intervals thereafter. A hundred percent immobilisation was seen at the highest test concentration (nominal 500 mg/L, geometric mean of measured concentrations over 48 hours 271.06 mg/L) - 90% of daphnids were already immobile after 24 hours at this test concentration. No immobilisation after 48 hours was seen at the nominal test concentration of 125 mg/L (no analytical confirmation of nominal concentration). The EC50 value could not be determined appropriately and was in the range from 125 mg/L to 271.06 mg/L. This value was used in the hazard assessment for the aquatic environment. Since no marine toxicity tests were available, the data generated with freshwater species were also used for the hazard assessment for the marine aquatic environment. The EC50 value for methyl lactate was significantly greater than that of its major breakdown product in water - L-menthol - which produced and EC50 value of 26.6 mg/L with daphnids in an aquatic toxicity test over a period of 48 hours.