[3aR-(3aα,5aβ,9aα,9bβ)]-dodecahydro-3a,6,6,9a-tetramethylnaphtho[2,1-b]furan

Ecotoxicological Summary

Hazard for aquatic organisms

Freshwater

Hazard assessment conclusion:

PNEC aqua (freshwater)

PNEC value:

4 µg/L

Assessment factor:

50

Extrapolation method:

assessment factor

Marine water

Hazard assessment conclusion:

PNEC aqua (marine water)

PNEC value:

0.4 µg/L

Assessment factor:

500

Extrapolation method:

assessment factor

STP

Hazard assessment conclusion:

PNEC STP

PNEC value:

10 mg/L

Assessment factor:

10

Extrapolation method:

assessment factor

Sediment (freshwater)

Hazard assessment conclusion:

PNEC sediment (freshwater)

PNEC value:

2.114 mg/kg sediment dw

Extrapolation method:

equilibrium partitioning method

Sediment (marine water)

Hazard assessment conclusion:

PNEC sediment (marine water)

PNEC value:

0.211 mg/kg sediment dw

Extrapolation method:

equilibrium partitioning method

Hazard for air

Air

Hazard assessment conclusion:

no hazard identified

Hazard for terrestrial organisms

Soil

Hazard assessment conclusion:

PNEC soil

PNEC value:

0.421 mg/kg soil dw

Extrapolation method:

equilibrium partitioning method

Hazard for predators

Secondary poisoning

Hazard assessment conclusion:

PNEC oral

PNEC value:

22.22 mg/kg food

Assessment factor:

90

Additional information

Justification for Read-across:

Please refer to the justification document attached to section 13.

 

Environmental fate and pathways:

The registered substance, (-)-(3aR,5aS,9aS,9bR)-3a,6,6,9a-Tetramethyldodecahydronaphtho[2,1-b]furan, contains no organic functional groups that may hydrolyse under environmental condition like alkyl halides, amides, amines, epoxides, esters. This substance consists only of organic functional groups that are relatively or completely inert with respect of hydrolysis. Based on the chemical structure an estimation of the hydrolysis rate is not possible. This statement is supported by one study showing that the registered substance is hydrolytically stable under the conditions of the test (the disappearance of the substance after 5 days as well as after 28 days is less than 10% at any pH (from 2 to 12) at 40°C).

Based on the key biodegradation study, the registered substance is readily biodegradable and therefore is not considered persistent in the environment. Finally, based on data on a source substance (which is the racemic form of the registered substance), (±)-(3aR*,5aS*,9aS*,9bR*)-3a,6,6,9a-Tetramethyldodecahydronaphtho[2,1-b]furan, the adsorption coefficient (Koc) of the registered substance can be determined at 5250, corresponding to a log Koc at 3.72 . The result indicates that the registered substance is environmentally immobile in soils, according to P.J. McCall et al., 1980 and not bioaccumulate in the rainbow trout. based on data on a source substance, the geometric mean Bioconcentration factor (BCF) of the registered substance can be determined at 373, the result indicates that the substance is not bioaccumulable. Based on structural similarity and common physico-chemical properties between these isomers, this source substance is considered adequate for read-across purposes (see IUCLID section 13 for justification).

 

Aquatic toxicity:

The aquatic toxicity of the registered substance, (-)-(3aR,5aS,9aS,9bR)-3a,6,6,9a-Tetramethyldodecahydronaphtho[2,1-b]furan, was assessed using data performed on the registered substance and on source substance, Reaction mass of (3aR,5aS,9aS,9bR)-3a,6,6,9a-tetramethyldodecahydronaphtho[2,1-b]furan and (3aS,5aR,9aR,9bS)-3a,6,6,9a-tetramethyldodecahydronaphtho[2,1-b]furan. This compound is the racemic form of the registered substance. Based on structural similarity and common physico-chemical properties between these isomers, and the same results on the observed toxicity to aquatic invertebrates (no acute effect up to the attainable limit of solubility in test medium, see ECHA disseminated dossier of the read-across substance EC# 701-326-2), this source substance is considered adequate for read-across purposes (see IUCLID section 13 for justification).

 

No toxic effects were observed up to the attainable limit of solubility of the registered and/or source substances in acute studies for the three aquatic trophic levels (fish, aquatic invertebrates and algae) at the maximum attainable mean test concentration.

Regarding long-term exposure, no toxic effect was observed in the algae experimental study at the maximum attainable mean test concentration and in an experimental chronic Daphnia study ( NOACK, 2021) the LOEC value for aquatic invertebrates, based on reproduction, was determined to be > 0.937 mg/L. The value predicted by calculation method (KREATiS, 2021)  21d - EL10 = 0.2 mg/L supports this value. 

A testing proposal is included in the dossier to conduct an experimental Fish  reproduction test, according to OECD Guideline 210, on the registered substance. The test on Fish is proposed, since according to the outcome of iSafeRat QSAR model, fish is the most sensitive species in chronic exposure. An experimentally- determined EC10 value would allow to conclude appropriately on the environmental classification of the registered substance. After acceptance of the submitted testing proposal for a Fish reproduction test, by ECHA, and when the new experimental study report is made available, the dossier and the final environmental classification will be updated.

 

In accordance with column 2 of REACH Annex VIII, the activated sludge respiration inhibition test does not need to be conducted because the substance is readily biodegradable, according to the OECD 301F study. The applied test concentrations (100 mg/L) are in the range of concentrations that can be expected in the influent of a sewage treatment plant, and no inhibition effects on the activity of microorganisms was observed. This statement is supported by one study, performed on the registered substance, according to DIN Guideline 38412 part 27 with GLP statement. The test substance had no inhibitory effect on the respiration rate of Pseudomonas putida after the incubation period of 30 min at the test item concentration of 10 g/L.

 

Terrestrial toxicity:

Effects of source substance on mortality, biomass and the reproductive potential of the earthworm species Eisenia fetida (Annelida, Lumbricidae) were determined according to OECD 222 (2016) with GLP compliance . Under the test conditions, the NOEC was determined to be at least the nominal concentration 200 mg test item/kg SDW and EC10 at 92.2 mg test item/kg SDW.

Conclusion on classification

No harmonised classification is available.

 

Data available:

- readily biodegradable;

- average BCF value of 373 L/kg (in vivo OECD Guideline 305 and in vitro biotransformation assay using liver S9 fractions and hepatocytes from rainbow trout)

- acute data: no acute toxic effects were observed on all trophic levels at or even close to the water solubility of the substance;

- chronic data: LOEC  > 0.937 mg/L for Daphnia. 

The test on fish is proposed, since according to the outcome of iSafeRat QSAR model, Fish is the most sensitive species in chronic exposure. An experimentally- determined EC10 value would allow to conclude appropriately on the environmental classification of the registered substance. After acceptance of the submitted testing proposal for a Fish early stage toxicity study by ECHA, and when the new experimental study report is made available, the dossier and the final environmental classification will be updated.

Classification according to the Annex I of the Regulation (EC) No 1272/2008 (CLP): The registered substance is not classified as for the environment based on chronic toxicity data and the ready biodegradability.