Registration Dossier

Ecotoxicological information

Endpoint summary

Administrative data

Description of key information

Reliable short-term toxicity tests results are available for freshwater fish (Oncorhynchus 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 tested) (exposure is predominantly to the Gem Diol form).

Activated sludge respiration inhibition: 3 hour EC50 value of >1000 mg/l (highest concentration tested) and a 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 (exposure is predominantly to the Gem Diol form).

Additional information

In the presence of water, Cyrene, specifically its keto group [C=O], gains water (H2O) to form the corresponding Gem Diol [C(OH)2]. An equilibrium is established rapidly and is completely reversible. The ratio of the two forms depends upon the amount of water present. 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, CSR Section 1.4) and in the attached assessment report in Section 13 of IUCLID.

No long-term aquatic toxicity data are available for fish and Daphnia. The Annex IX data requirements have therefore been fulfilled using QSAR predicted data.

For completeness, and to compare estimated sensitivities of the test organisms for indicative PNEC derivation, predicted algal toxicity data have also been included as supporting data.

 

The aqueous form of the registered substance, the Gem Diol, is the relevant species for aquatic assessment, therefore the properties of the Gem Diol have been used as the input parameters for the QSAR.

The relevant predicted values, using ECOSAR v2.0 for the prediction of the aquatic toxicity of neutral organics, are:

Fish QSAR: 96-hour LC50 174058 mg/l and 30-day NOEC mg/l 6482 mg/l.

Daphnia QSAR: 48-hour EC50 71407 mg/l and 16-day NOEC 1575 mg/l.

Algae QSAR: 96-hour EC50 13875 mg/l and NOEC 985 mg/l.

 

Refer to IUCLID Section 6.0, Ecotoxicological information, and CSR Section 7.0 for further discussion of the approach to chemical safety assessment for this registration substance.