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Environmental fate & pathways

Adsorption / desorption

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Reference
Endpoint:
adsorption / desorption: screening
Type of information:
(Q)SAR
Adequacy of study:
key study
Study period:
November 2014
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: accepted calculation method of a component
Justification for type of information:
QSAR prediction
Qualifier:
no guideline followed
Principles of method if other than guideline:
(Q)SAR calculation with calculation program US EPA EPI-Suite v4.0, component KOCWIN (v2.00) using first-order molecular connectivity index (1-MCI) corrected by fragment contribution factors for polar compounds
Type of method:
other: calculation
Key result
Type:
log Koc
Value:
2.877
Remarks on result:
other: calculated value, log Kow method
Key result
Type:
log Koc
Value:
2.477
Remarks on result:
other: calculated value, MCI method
Key result
Type:
Koc
Value:
753.6
Remarks on result:
other: calculated value, log Kow method
Key result
Type:
Koc
Value:
300.2
Remarks on result:
other: calculated value, MCI method

MCI method

 

First Order Molecular Connectivity Index :   6.719

Non-Corrected Log Koc (0.5213 MCI + 0.60) :   4.1023

Fragment Correction(s):

       Organic Aicd (-CO-OH) :       -1.6249

Corrected Log Koc :   2.4774

 

Estimated Koc :   300.2 L/kg

 

Log Kow method

Log Kow (Kowwin estimate) : 4.92

Non-Corrected Log Koc (0.55313 logKow + 0.9251): 3.6465

Fragment Correction(s):

        

Organic Aicd (-CO-OH):       -0.7694

Corrected Log Koc : 2.8771

 

Estimated Koc : 753.6 L/kg

Validity criteria fulfilled:
not applicable
Conclusions:
2-butyl octanoic acid has a medium Koc indicating a low to medium soil mobility potential.
Executive summary:

The Koc of 2 -butyl octanoic acid was estimated with the program US EPA EPI Suite (v 4.00), program component KOCWIN. Using a correlation based on molecular connectivity index, the log Koc was determined to be 2.477 (Koc = 300.2 L/kg). Using a correlation based on Kow, the log Koc was 2.877 (Koc = 753.6 L/kg). The high Koc values indicate a distinct potential of 2 -butyl octanoic acid to accumulate in soil and sediment.

The McCall classification scheme classifies the substances as low to medium soil mobility potential (Koc 150 -2000).

The KOC of this structure may be sensitive to pH. The estimated KOC represents a best-fit to the majority of experimental values. However, the KOC may vary significantly with pH.

McCall et al., 1981, Measurement of Sortpion coefficients of organic chemicals and their use in environmental fate analysis

Description of key information

Log Koc was calculated to 4.1023 (MCI method). Optionally, log Koc was estimated to 2.8771 and KOC was estimated 753.6 using log Kow.

Key value for chemical safety assessment

Koc at 20 °C:
753.6

Additional information

The Koc of 2 -butyl octanoic acid was estimated with the program US EPA EPI Suite (v 4.00), program component KOCWIN. Using a correlation based on molecular connectivity index, the log Koc was determined to be 2.477 (Koc = 300.2 L/kg). Using a correlation based on Kow, the log Koc was 2.8771 (Koc = 753.6 L/kg). The high Koc values indicate a distinct potential of 2 -butyl octanoic acid to accumulate in soil and sediment.

The McCall classification scheme classifies the substances as low to medium soil mobility potential (Koc 150 -2000).

The KOC of this structure may be sensitive to pH. The estimated KOC represents a best-fit to the majority of experimental values. However, the KOC may vary significantly with pH.

[LogKoc: 2.8771]