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Adsorption / desorption

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Reference
Endpoint:
adsorption / desorption: screening
Type of information:
(Q)SAR
Adequacy of study:
key study
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:
For detailed description on the model and its applicability, see attached QMRF and QPRF document.
Reference:
Composition 0
Principles of method if other than guideline:
Calculation based on KOCWIN v2.00, Estimation Programs Interface Suite™ for Microsoft® Windows v 4.11. US EPA, United States Environmental Protection Agency, Washington, DC, USA
GLP compliance:
no
Type of method:
other: calculation
Media:
soil
Test material information:
Composition 1
Type:
log Koc
Value:
1.913 dimensionless
Temp.:
25 °C
Remarks on result:
other: Estimate from MCI
Type:
Koc
Value:
81.91 L/kg
Temp.:
25 °C
Remarks on result:
other: Estimate from MCI
Type:
log Koc
Value:
1.811 dimensionless
Temp.:
25 °C
Remarks on result:
other: Estimate from Log Kow
Type:
Koc
Value:
64.78 L/kg
Temp.:
25 °C
Remarks on result:
other: Estimate from Log Kow

As no single computational model could be identified which would fit completely to the substance, the log Koc of the substance was calculated as the arithmetic mean of the data generated by two individual QSAR approaches. The QSAR model using the log Kow as input parameter was based on the experimentally derived log Kow of 2.23.

 

Method

Type

Value

Estimate from MCl

Log Koc

1.9134

 

Koc

81.91 L/kg

Estimate from Log Kow

Log Koc

1.8114

 

Koc

64.78 L/kg

Arithmetic mean

Log Koc

1.8624

 

Koc

72.85 L/kg

 

An arithmetic mean log Koc of 1.86 with a corresponding Koc of 72.85 L/kg resulted.

Conclusions:
The reliable (Q)SAR prediction resulted in a low potential of the substance for adsorption to organic soil and sediment particles (log Koc: 1.8114 - 1.9134; arithmetic mean: 1.86).

Description of key information

As no single computational model could be identified which would fit completely to the substance, the log Koc of the substance was calculated as the arithmetic mean of the data generated by two individual QSAR approaches. The log Koc was estimated by (Q)SAR calculations to be 1.91 (based on MCI) and 1.81 (log Kow). A mean log Koc of 1.86 with a corresponding Koc of 72.85 L/kg was calculated indicating a low potential for adsorption to soil and sediment particles.

Key value for chemical safety assessment

Koc at 20 °C:
72.85

Additional information

No experimental studies investigating the adsorption/desorption potential of the substance are available. Therefore, the log Koc was calculated using KOCWIN v2.00 based on the Molecular Connectivity Index (MCI) and based on log Kow. Calculations resulted in log Koc values of 1.91 (based on MCI) and 1.81 (log Kow). A mean log Koc of 1.86 was calculated, indicating that the substance has a low potential to adsorb to organic soil and sediment particles.

[LogKoc: 1.86]