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Environmental fate & pathways

Adsorption / desorption

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Description of key information

The adsorption log Koc values for the three main constituents of the substance are 4.6, 5.4 and 6.30-6.69.

Key value for chemical safety assessment

Koc at 20 °C:
251 189

Additional information

One reliable experimental data and QSAR estimations data are available for 99422018.

Experimental versus Predictive data

For two of the three constituents from 99422018, the EPIWin calculations of Log Koc (5.17 -5.72 & 4.26 -4.74) correspond to the experimental Log Koc values (5.4 & 4.6). For the third constituent, the experimental Log Koc is determined to > 5.6; however, the constituents are analogous substances which differ in the alkyl chain length.

From the comparison of QSAR output estimations and the experimental data, there is some evidence that the QSAR predictions for Log Koc are accurate for the constituents of 99422018. Thus, using a weight of evidence it is proposed to cover the Log Koc information for the third constituent by the appropriate QSAR estimations values (6.30 -6.69).

Determining a single key value

The determination of single Koc for the purpose of the chemical safety assessment is a critical issue for multi-constituent substance. The key Koc value is determined to 251,000 (Log Koc ca. 5.4). This key value would correspond approximately to the weight-average value using Epiwin calculations and corresponds approximately to the experimental Log Koc value for the constituent which exhibits an intermediate structure.

[LogKoc: 5.4]