Litsea cubeba, ext.

Adsorption / desorption

Link to relevant study record(s)

Reference

Endpoint:

adsorption / desorption: screening

Type of information:

(Q)SAR

Adequacy of study:

key study

Study period:

09 May 2018

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:

According to annex VIII 9.3.1 of the REACH Regulation EC/2006/1907, “Adsorption/desorption screening” is standard information required for the registration of substances manufactured or imported in quantities of ten tonnes per year or more. REACH accepts and encourages the use of QSARs validated in accordance with the OECD Principles.The requirements for REACH can be considered as met as described in the reports (attached below), and because full information is provided in the registration dossier. This includes a robust study summary and an endpoint summary included in the IUCLID dossier. As well as supported information from a QMR that describes the QSAR model, and a QPR that reports the predictions.

Principles of method if other than guideline:

The MCI methodology was selected to estimate the log Koc. QSAR estimation methodology based on the MCI methodology is described in a journal article (Meylan et al, 1992) and in a report prepared for the US EPA (SRC, 1991). The same methodology as described in (Meylan et al, 1992) was used to develop the QSAR equations utilizing Molecular Connectivity Index (MCI). Two separate regressions were performed in the MCI methodology. The first regression related log Koc of non-polar compounds (n = 69) to the first-order MCI. The second regression included the 447 compounds having correction factors; Correction factors are specific chemical classes or structural fragments. The regression coefficients were derived via multiple linear regression of the correction descriptors to the residual error of the prediction from the non-polar equation. See QPR and QMRF for more information.

GLP compliance:

no

Remarks:

Not required for a calculation based on QSAR methods

Type of method:

other: QSAR

Media:

soil

Details on study design: HPLC method:

Not required for a calculation based on QSAR methods

Key result

Type:

log Koc

Value:

>= 1.622 - <= 4.251 dimensionless

Temp.:

20 °C

Remarks on result:

other: Calculation based on QSAR

Predicted value (model result)

Constituent	CAS-number	Log Koc	Koc(L/kg)
L-Limonene	5989-54-8	3.049	1.12E+03
Neral	106-26-3	1.687	4.87E+01
Geranial	141-27-5	1.687	4.87E+01
(+)-Citronellal	2385-77-5	1.687	4.87E+01
Geraniol	106-24-1	1.974	9.41E+01
β-(+)-Citronellol	1117-61-9	1.974	9.41E+01
Methyl Heptenone	110-93-0	1.622	4.18E+01
(-)-linalol	126-91-0	1.877	7.52E+01
β-Caryophyllene	87-44-5	4.251	1.78E+04
α-Pinene	7785-26-4	3.009	1.02E+03
1,8-Cineole	470-82-6	2.345	2.21E+02
Sabinene	3387-41-5	3.032	1.08E+03
β-Myrcene	123-35-3	3.031	1.07E+03
Verbenol	473-67-6	1.905	8.03E+01
Nerol	106-25-2	1.974	9.41E+01
Isogeranial	72203-98-6 / 55722-59-3	1.687	4.87E+01
Isoneral	72203-97-5	1.687	4.87E+01

Validity criteria fulfilled:

yes

Remarks:

QSAR model validated to be compliant with the OECD recommendation for QSAR modelling (OECD, 2004) described within the QMRF.

Conclusions:

The predicted Log Koc of the known constituents of the UVCB Litsea cubeba oil was in the log Koc range of 1.622 to 4.251.

Executive summary:

A QSAR approach, based on EpiSuite KOCWIN MCI methodology, was used to predict the log Koc range for adsorption /desorption exposed to the test item Litsea cubeba oil. Two separate regressions were performed in the MCI methodology. The first regression related log Koc of non-polar compounds (n = 69) to the first-order MCI. The second regression included the 447 compounds with correction factors.The regression coefficients were derived via multiple linear regression of the correction descriptors to the residual error of the prediction from the non-polar equation. All criteria for the application of QSARs under REACH were met. The predictions for adsorption/desorption in soil were considered to be adequate and fit-for-purpose. The predicted Log Koc of the known constituents of the UVCB Litsea cubeba oil was in the log Koc range of 1.622 to 4.251.

Description of key information

A QSAR approach, based on EpiSuite KOCWIN MCI methodology, was used to predict the log Koc range for adsorption /desorption exposed to the test item Litsea cubeba oil. Two separate regressions were performed in the MCI methodology. The first regression related log Koc of non-polar compounds (n = 69) to the first-order MCI. The second regression included the 447 compounds with correction factors.The regression coefficients were derived via multiple linear regression of the correction descriptors to the residual error of the prediction from the non-polar equation. All criteria for the application of QSARs under REACH were met. The predictions for adsorption/desorption in soil was considered to be adequate and fit-for-purpose. The predicted Log Koc of the known constituents of the UVCB Litsea cubeba oil was in the log Koc range of 1.622 to 4.251.

Additional information

For Litsea cubeba, predicted log Koc values range between 1.622 to 4.251. This indicates potential for low to strong sorption to soil/sediment, depending on the constituent.