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

Ecotoxicological Summary

Hazard for aquatic organisms

Freshwater

Hazard assessment conclusion:

no hazard identified

Marine water

Hazard assessment conclusion:

no hazard identified

STP

Hazard assessment conclusion:

no hazard identified

Sediment (freshwater)

Hazard assessment conclusion:

insufficient hazard data available (further information necessary)

Sediment (marine water)

Hazard assessment conclusion:

insufficient hazard data available (further information necessary)

Hazard for air

Air

Hazard assessment conclusion:

no hazard identified

Hazard for terrestrial organisms

Soil

Hazard assessment conclusion:

PNEC soil

PNEC value:

1.16 mg/kg soil dw

Assessment factor:

100

Extrapolation method:

assessment factor

Hazard for predators

Secondary poisoning

Hazard assessment conclusion:

no potential for bioaccumulation

Additional information

Environmental fate and pathways:

As described in the physical and chemical properties summary, the registered substance is a liquid of very low water solubility and very low volatility.

The registered substance is not readily biodegradable but a strong and consistent evidence of mineralisation was provided. Therefore, the registered substance is inherently biodegradable (not fulfilling specific criteria) and not persistent in the environment. Delta-Damascone mercapto acetic acid (DD-ma) was identified as the main degradation product. This compound is slowly degraded and in the absence of other biodegradation study on this metabolite, DD-ma is considered as potentially persistent (P) or very persistent (vP).All larger metabolites found can be considered as transient intermediates.

Regarding the bioaccumulation potential, with a measured log Kow value at 9.5, the registered substance would not be expected to bioaccumulate significantly. This statement was confirmed with an experimental bioaccumulation study, performed for a Japan notification on the registered substance, and showing a BCF value lower than 38. The registered substance is not considered as bioaccumulable. Also, the final degradation product of the registered substance, DD-ma, is not expected to bioaccumulate significantly in the environment with a log Kow at 3.1 (arithmetical mean value of QSAR results).

Finally, the adsorption coefficient (Koc) of the registered substance was estimated by the KOCWIN v2.00 model to be 1953500 L/kg (log Koc = 6.3), using an experimental log Kow value at 9.5, indicated that the registered substance is immobile in soil(according to P.J. McCall et al., 1981).

Aquatic toxicity:

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.

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 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 likely to be technically feasible for this substance.

As a 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. 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)).

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).

Terrestrial toxicity:

Two reliable key studies are available to assess the toxicity of the registered substance to earthworm. The first study (Harlan, 2011) assess the acute toxicity effects using the filter paper contact test according to OECD Guideline 207 and the second study (Fraunhofer, 2015) assess the chronic toxicity effects according to OECD Guideline 222.

In the first study (Harlan, 2011), no mortality on the earthworms Eisenia fetida was observed at the end of the 48h-test for all test concentrations used. Therefore, the 48h-EC50 was greater than the maximum tested concentration, 4.0 mg/cm².

In the second study (Fraunhofer, 2015), no increased mortality and no significant influence on weight change were found up to the maximum tested concentration, 1000 mg/kg dry soil. However, reproduction was significantly affected starting at 125 mg/kg dry soil. The NOEC for reproduction was found to be 62.5 mg/kg dry soil and the EC10 was found to be 116 mg/kg dry soil (95 % CL: 45 – 185 mg/kg dry soil). As NOECs are increasingly contested in ecotoxicology because it's not a statistically interpolated value, the EC10 value at 116 mg/kg dry soil is prefered to assess the chronic effects.

In conclusion, the test substance has no acute effects on earthworm but has chronic effects, based on reproduction, under the chosen test conditions. The relevant chronic value is defined as the EC10 at 116 mg test substance/kg dry soil (95 % CL: 45 – 185 mg/kg dry soil).

Conclusion on classification

Based on the very low water solubility of the registered substance, it's technically not feasible to obtain a relevant aquatic endpoint value. The substance had no acute toxic effects on aquatic organisms up to and significantly higher than its solubility limit in test water. The long-term toxicity effects cannot be evaluated. The substance is not readily biodegradable but is not considered bioaccumulative based on a log Kow at 9.5 and the ongoing experimental bioaccumulation study (BCF < 50).

Classification according to the Annex VI of the Regulation (EC) No 1272/2008 (CLP): The registered substance is not classified for the environment.