1,6-Octadien-3-ol, 3,7-dimethyl-, acid-isomerized

Short-term toxicity to aquatic invertebrates

Description of key information

For the purposes of the environmental risk assessment, two assessment entities have been defined. For both groups, the daphnia endpoint was identified as the most sensitive species (see aquatic toxicity endpoint summary for details). The following 48h EC50 values have been estimated and used to derive PNECaquatic for the corresponding assessment entities:

- Unsaturated Monoterpene Hydrocarbons: 0.215 mg/L (lowest QSAR value of all component predictions)

- Monoterpene Ethers: 32mg/L (based on the representative substance, Limetol)

For the purposes of classification and labelling, data on the whole substance is used. A study performed on Lime oxide gave an acute 48h EL50 of 5.3mg/L based on WAF loading rates.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

5.3 mg/L

Additional information

A study was performed to assess the acute toxicity of the registered substance to Daphnia Magna. The test item is a complex mixture composed of constituents with different water solubility (i.e. unsaturated monoterpene hydrocarbons and oxygen-containing monoterpenes) and therefore the test item was prepared as Water Accommodated Fractions (WAFs). Following a preliminary range-finding test, twenty daphnids (4 replicates of 5 animals) were exposed to Water Accommodated Fractions (WAFs) of the test item over a range of nominal loading rates of 2.6, 6.2, 16, 40 and 100 mg/L for 48 hours at a temperature of approximately 20 °C under static test conditions. The number of immobilized Daphnia and any adverse reactions to exposure were recorded after 24 and 48 hours. The test item was suspected to be volatile and hence testing was conducted in completely filled, stoppered test vessels in order to minimize possible losses due to volatilization.

GC analysis using the total peak area associated with the test item, showed measured test concentrations at 0h of 0.892, 1.76, 4.25, 10.2 and 21.8mg/L. Measured test concentrations after 48 hours were 84 to 100% of initial, indicating that the dissolved test item concentration had been maintained throughout the exposure period.

The dissolved test item may have been one or several components of the test item. Given that toxicity cannot be attributed to a single component or mixture of components but to the test item as a whole, the results were based on nominal loading rates only. The determined 48h EL50 was 5.3 mg/L. This value has been used for classification of the registered substance.