Registration Dossier

Ecotoxicological information

Endpoint summary

Administrative data

Description of key information

Reliable short-term toxicity tests results are available for freshwater fish (Onychorynchus mykiss), invertebrates (Daphnia magna) and algae (Scenedesmus subspicatus) for (1S,5R-6,8-dioaxbicyclo[3.2.1]octan-4-one (Cyrene™, CAS 53716-82-8, EC 807-130-4). The relevant short-term values are:


Fish: LC50 (96 h): >100 mg/l; NOEC: ≥100 mg/l (based on mortality) (limit test) (exposure is predominantly to the Gem Diol form).

Daphnia: EC50 (48 h): >100 mg/l; NOEC: ≥100 mg/l (based on mobility) (limit test) (exposure is predominantly to the Gem Diol form).

Algae: EC50 (72 h): >100 mg/l; EC10: >100 mg/l, NOEC: ≥100 mg/l (based on growth rate) (highest concentration test) (exposure is predominantly to the Gem Diol form).

Activated sludge respiration inhibition: 3 hour EC50 value of >1000 mg/l (highest concentration tested) and an NOEC of 500 mg/l (nominal concentrations) have been determined for the effects of the test substance, Cyrene™ on respiration inhibition of activated sludge, in compliance with OECD Test Guideline 209.

Additional information

In the presence of water, CyreneTM, with its anhydrous keto group [C=O], gains water (H2O) to form the corresponding hydrated Gem Diol [C(OH)2]. An equilibrium is established rapidly and is completely reversible. When the amount of water is reduced, the Gem Diol loses water, regenerating the anhydrous CyreneTM in its keto form. The ratio of the two forms depends upon the amount of water present and hence the polarity of the solution. At concentrations relevant for the environment and in vivo, the Gem Diol form predominates. Further information (including discussion of analytical methods used in the ecotoxicology studies) is available in the Physical and chemical properties endpoint summary (IUCLID Section 4).