Reaction Mass of (4R)-4-isopropenyl-1-methylcyclohexene and (4R)-4-(2-methoxypropan-2-yl)-1-methylcyclohexene

Short-term toxicity to fish

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to fish

Type of information:

(Q)SAR

Adequacy of study:

key study

Study period:

07 - 10 November 2016

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

results derived from a valid (Q)SAR model and falling into its applicability domain, with adequate and reliable documentation / justification

Guideline:

other: REACH guidance on QSARs R.6, OECD Guideline 203 (Fish, Acute Toxicity Test), with modifications from OECD Series on Testing and Assessment no. 23 on ecotoxicity testing of difficult substances.

Principles of method if other than guideline:

The QSAR method was validated using data from tests preformed using the OECD document 23 recommnedations for poorly water soluble complex mixtures. The QSAR is thus validated not be compliant inline with such methods/recommendations.

Specific details on test material used for the study:

The substance is a mixture. The toxicity is, therefore, based on seperately determined QSAR endpoints for each constiuent, the reports for which can be found in section 6.1.1 of this dossier.

Key result

Duration:

96 h

Dose descriptor:

LL50

Effect conc.:

5.8 mg/L

Remarks on result:

other: QSAR predicted value

Conclusions:

The 96 hour LL50 to fish of the reaction mass of (4R)-4-isopropenyl-1-methylcyclohexene and (4R)-4-(2-methoxypropan-2-yl)-1-methylcyclohexene, estimated from the iSafeRat v.2.2 QSAR inputs from each constituent and, calculations based on thermodynamics of each constituent and there eventual contribution to the toxicity was 5.8 mg/L. The endpoint value is considered valid for use in risk assessment (including PBT assessment) and classification and labelling. The prediction is adequate as contributing data for the Classification and Labelling or risk assessment of the substance as indicated in REACH Regulation (EC) 1907/2006: Annex XI Section 1.3.

Executive summary:

This approach uses a thermodynamically based module to calculate the water concentrations and the individual toxicity of each of the constituent is first derived from a QSAR model validated to be compliant with the OECD recommandations for QSAR modeling (OECD, 2004). Then the effective loading rate of the mixture to the test organisms (i.e. fish) is determined as a Water Accommodated Fraction (WAF) test (OECD, 2000).

The inputs into the model all came from reliable QSAR estimations. The endpoint value is considered valid for use in risk assessment (including PBT assessment) and classification and labelling. The prediction is adequate as contributing data for the Classification and Labelling or risk assessment of the substance as indicated in REACH Regulation (EC) 1907/2006: Annex XI Section 1.3.

The 96 hour LL50 for the test substance was estimated to be 5.8 mg/L.

Description of key information

Constituent 1: 96h Lc50 = 0.46 mg/L; REACH guidance on QSARs R.6, OECD Guideline 203 (Fish, Acute Toxicity Test), with modifications from OECD Series on Testing and Assessment no. 23 on ecotoxicity testing of difficult substances (Anon., 2017).

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Effect concentration:

0.46 mg/L

Additional information

Ecotox endpoints and expected concentrations of each constituent in the mixture (based on % composistion w/w)

Constituent Name	96h-LC50^a (mg/L)	Concentration in the WAF (mg/L)
(4R)-4-isopropenyl-1-methylcyclohexene (limonene)	0.46	1.3
(4R)-4-(2-methoxy-2-propanyl)-1-methylcyclohexene (ether MT)	9.8	2.7
1-methyl-4-(2-propanylidene)cyclohexene (terpinolene)	0.55	0.44
cis-1-methoxy-1-methyl-4-(1-propen-2-yl)cyclohexane (cis-1-methoxy-8-pmenthene)	9.3	0.23
2-[(1S)-4-methyl-3-cyclohexen-1-yl]-2-propanol (α-terpineol)	69	0.16
trans-1-methoxy-1-methyl-4-(1-propen-2yl)cyclohexane (trans-1-methoxy-8-p-menthene)	9.3	0.07
1-methoxy-1-methyl-4-(2-propanylidene)cyclohexane (1-methoxy-4-p-menthene)	11	0.14
cis-1-methoxy-4-(2-methoxypropan-2-yl)-1-methylcyclohexane (cis-1,8-dimethoxy-p-menthane)	198	0.43
trans-1-methoxy-4-(2-methoxypropan-2-yl)-1-methylcyclohexane (trans-1,8-dimethoxyp-menthane)	198	0.06
7-methyl-3-methylene-1,6-octadiene (myrcene)	0.32	0.02
1-methyl-4-(2-propanyl)-1,3-cyclohexadiene (α-terpinene)	0.40	0.03
1-methyl-4-(2-propanyl)-1,4-cyclohexadiene (γ-terpinene)	0.55	0.03

^aindividual reports for each constituent presented in Section 6.1.1

The 96h LC50 for constituent 1 = 0.46 mg/L is used for chemical safety assessment.