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Toxicity data are available for all three trophic levels in the aquatic compartment (primary producers/algae; invertebrates/Daphnia; fish). Acute toxicity has been directly investigated in algae and Daphnia, and studies of a close chemical analogue of dihydromyrcenol (linalool) provide information on acute toxicity to fish and long-term toxicity to Daphnia. Fish were by a small margin most sensitive, giving a 96h LC50 value of 27.8 mg/l (for linalool). Daphnia magna and algal growth inhibition studies with dihydromyrcenol gave EC50s of 38 mg/l and 80 mg/l (growth rate) respectively.

In a 21-day Daphnia reproduction study, the close analogue linalool gave a NOEC value of 9.5 mg/l, suggesting that the chronic toxicity of dihydromyrcenol to aquatic organisms will be relatively low.

Justification for the use of linalool as a read-across analogue of dihydromyrcenol is provided by the following considerations:

- both are linear (non-cyclic), unsaturated terpenoid tertiary alcohols

- their physical properties are generally similar (liquids at NTP, with boiling points circa 190-200°C, vapour pressures circa 0.2-0.3 hPa and water solubilities >800 mg/l. Log Kow values closely similar at 2.97 and 3.25).