[1S-(1α,3aβ,4α,8aβ)]-decahydro-4,8,8-trimethyl-9-methylene-1,4-methanoazulene

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

Endpoint:

toxicity to aquatic algae and cyanobacteria

Remarks:

ErC50 at 72/96h

Type of information:

(Q)SAR

Adequacy of study:

key study

Study period:

2016-2017

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

Justification for type of information:

The executive summary of the (Q)SAR prediction is presented below.
The acute algae ErC50 for the neutral organic substance Longifolene is predicted to be 0.28 mg/L based on the ECOSAR SAR for neutral organics using an estimated log Kow of 5.48, molecular weight of 204.4 and the equation: Log 96h-EC50 (mmol/L) = -0.6922 log Kow + 0.9253.
Longifolene is in the applicability domain of the ECOSAR prediction because: a) Longifolene is a neutral organic substance presenting the toxicity solely by its bioavailability (i.e. without fragments that activate this neutral organic substance); b) its log Kow is 5.48 (=< 6.4); c) its MW is 204.4 (< 1000); and; d) the toxicity predicted is below its measured water solubility of 7.9 mg/L.
There is limited uncertainty of the prediction. The measured and predicted log Kow’s are similar (5.0 and 5.48, respectively). The measured EC50 values of the substances in the ECOSAR training with similar log Kows are similar to what is predicted for Longifolene. The neutral organic fragrance types present higher EC50 values, indicating that the calculated EC50 for Longifolene could be conservative (see QMR).
The fit in the applicability domain and the availability of substances in the training set with similar log Kow results in limited uncertainty of the Longifolene prediction. This shows that the prediction is reliable and a Klimisch 2 can be assigned. In accordance with REACH Annex XI, the validity of the (Q)SAR is documented in a QMR for acute algae toxicity on neutral organics (see attached report). The adequate and reliable documentation, presented below, further supports this prediction.

Qualifier:

according to guideline

Guideline:

other: REACH Guidance R.6: QSARs and grouping of chemicals. Version May 2008.

Deviations:

not applicable

GLP compliance:

no

Specific details on test material used for the study:

SMILES: C(C(C(C1=C)C2)C(CCC3)(C)C)(C13C)C2

Test organisms (species):

other: green algae

Water media type:

freshwater

Total exposure duration:

96 h

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

0.28 mg/L

Nominal / measured:

estimated

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: ECOSAR class: Neutral Organics

Based on the ECOSAR v1.11 the 72h-EC50 of Longifolene to green algae is 0.28 mg/L.

Validity criteria fulfilled:

yes

Remarks:

The ECOSAR-Neutral organics equation is valid when using the OECD criteria. In addition, N=41 and R2 is 0.68

Conclusions:

ECOSAR v1.11 predicted that the 96h-EC50 of Longifolene to green algae is 0.28 mg/L.

Executive summary:

The executive summary is presented in the 'Justification of information' section.

Key value for chemical safety assessment

EC50 for freshwater algae:

0.28 mg/L

EC10 or NOEC for freshwater algae:

0.15 mg/L