1-Butanone, 3-(dodecylthio)-1-[(1R,2S)-2,6,6-trimethyl-3-cyclohexen-1-yl]-, rel-

Endpoint summary

Description of key information

Acute data, reliable with restrictions (Klimisch rating), based on international guidelines, are available to assess the toxicity of the registered substance to the three trophic levels: Algae, Invertebrates and Fish and are summarised in the table 6.1/1 below.

Table 6.1/1: Summary of acute toxicity data for the registered substance

Organism	EC50/LC50	NOEC	Flag / reliability	Performing laboratory	Reference in IUCLID
Acute
Aquatic algae
Scenedesmus subspicatus	72h: > 0.021 mg/L	72h: 0.021 mg/L	K/2	Harlan	Toxicity to aquatic algae and cyanobacteria, Harlan, 2006, RS, K
Aquatic invertebrates
Daphnia magna	48h: > 0.072 mg/L	Not applicable	K/2	Safepharm	Short-term toxicity to aquatic invertebrates, Safepharm, 2006, RS, K
Daphnia magna	Not technically possible		S/2	Fraunhofer	Short-term toxicity to aquatic invertebrates, Fraunhofer, 2013, RS, S
Fish
Oncorhynchus mykiss	96h: > 0.071 mg/L	Not applicable	K/2	Safepharm	Short-term toxicity to fish, Safepharm, 2006, RS, K
Brachydanio rerio	96h: > 0.5 mg/L	Not applicable	S/2	Environmental Testing Laboratory, Shanghai	Short-term toxicity to fish, SAES, 2007, SS, S
Micro-organisms
activated sewage sludge	3h: >1000 mg/L	3h: 1000 mg/L	K/1	Safepharm	Toxicity to microorganisms, Safepharm, 2005, RS, K

Based on the very low water solubility of the substance, it's technically not feasible to obtain a relevant endpoint value. The substance had no acute toxic effects on aquatic organisms up to and significantly higher than its solubility limit in test water.

In addition, according to the supporting acute toxicity study on Daphnia magna (Fraunhofer, 2013), the total lack of reproducibility within the various replicates and concentration levels usig several different exposure methods demonstrates that it is not technically feasible to dissolved the substance in solution and to obtain reliable concentrations. Therefore, it is not possible to conduct a chronic Daphnia test and moreover aquatic toxicity tests in general are not considered to be technically feasible for this substance.

As strong and consistent evidence of mineralisation of the registered substance was provided, the acute toxicities of the degradation products, which are the relevant species for the environmental risk assessment, were determined using the ECOSAR v1.11 QSAR model available from the U.S. EPA, and are summarised in the table 6.1/2 below. The assessed degradation products were Delta-Damascone mercapto acetic acid (DD-ma) (which is the main degradation product) and two other larger metabolites (Delta-Damascone mercapto proprionic acid (DD-mp) and Delta-Damascone (DD)).

Table 6.1/2: ECOSAR estimation for degradation products

Degradation products	EC50/LC50	Reference in IUCLID
Acute
Aquatic algae
DD	96h: 5.22 mg/L	DD, Toxicity to aquatic algae and cyanobacteria, QSAR, ECOSAR, 2012, SS, S
DD-ma	96h: > 84.53 mg/L	DD-ma, Toxicity to aquatic algae and cyanobacteria, QSAR, ECOSAR, 2012, SS, S
DD-mp	96h: > 47.31 mg/L	DD-mp, Toxicity to aquatic algae and cyanobacteria, QSAR, ECOSAR, 2012, SS, S
Aquatic invertebrates
DD	48h: 3.80 mg/L	DD, Short-term toxicity to aquatic invertebrates, QSAR, ECOSAR, 2012, SS, S
DD-ma	48h: > 84.53 mg/L	DD-ma, Short-term toxicity to aquatic invertebrates, QSAR, ECOSAR, 2012, SS, S
DD-mp	48h: > 47.31 mg/L	DD-mp, Short-term toxicity to aquatic invertebrates, QSAR, ECOSAR, 2012, SS, S
Fish
DD	96h: 5.78 mg/L	DD, Short-term toxicity to fish, QSAR, ECOSAR, 2012, SS, S
DD-ma	96h: > 84.53 mg/L	DD-ma, Short-term toxicity to fish, QSAR, ECOSAR, 2012, SS, S
DD-mp	96h: > 47.31 mg/L	DD-mp, Short-term toxicity to fish, QSAR, ECOSAR, 2012, SS, S

According to these data, the degradation products are presumably not toxic (T) in a PBT assessment context.

The registered substance was considered as non-toxic to the microorganisms of a water treatment plant (3h-EC50 > 1000 mg/L).