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Environmental fate & pathways

Adsorption / desorption

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Description of key information

From a range of field studies on different matrices values for Koc have been determined. The values have been compared and it was shown that the predicted value based on log Kow (EUSES) was in the range of the field data. Thus the prediction (log Koc = 4.39) was used for the further distribution modelling.  

Key value for chemical safety assessment

Koc at 20 °C:
24 547

Additional information

Summary of Partition coefficients ('true' partition coefficients, or else determined from concentration ratios not excluding other processes like, e.g., degradation) from the EU-RAR (2008)

Partition coefficient

Estimated by EUSES

Experimental

log Koc in activated sludge

4.39 *)

'true' 4.87 (MacGillivray 1996)

'true' 3.8; 'apparent' 3.3 (Artola 2002)

'apparent' 4.5 (Blok 2005)

'true' 3.8 (based on Ternes et al. 2004)

activated sludge - water

Kd: 9150 l/kg

'true' Kd: 13,600 l/kg (MacGillivray 1996)

'apparent' Kd: 8570 l/kg (Blok et al. 2005)

'apparent' Kd: 33,500 l/kg (based on data Müller et al. 2003)

'true' Kd: 1810±530 l/kg (Ternes et al. 2004)

'true' Kd in primary sludge: 4,920 l/kg (Ternes et al. 2004)

true' log Kd (ads) 3.12, log Kd (des) 3.31 (Zhang et al. 2003)

soil - water­

Kd: 495 l/kg

Ksoil-water: 742 m3/m3

 Kd: 95 – 380 l/kg  (Müller et al. 2002)

log Koc in soil

 

3.6 – 3.9 (Müller et al 2002)

suspended matter -water

Kd: 2474 l/kg

Ksusp water: 619 m3/m3



'app' Kd: 5430 l/kg (with high variability, from data of Winkler 1998, 1999) 

'app' Kd: 845 l/kg (with high variability, HLUG 2001)

'app' Kd: 2400 – 5640 l/kg (Fooken 2004)

'app' Kd: 600 – 3700 (LfU-BW 2001)

log Koc in suspended matter

 

'app' 4.3 (Fooken 2004)

'app' 3.76 – 4.48 (LfU-BW 2001)

sediment - water

Kd: 1273 l/kg

Ksed.water: 619 m3/m3

Kd: 124 l/kg (Fooken 2004)

Kd: 63 – 180 l/kg (LfU-BW 2001)

log Koc in sediment

 

3.85 (Fooken 2004)

3.63 – 4.04 (LfU 2001)

*)based on log Kow, used in the further calculations in EUSES

Calculation: A Koc value for HHCB can be estimated from the Kow value of 5.3 using the QSAR outlined in chapter 4 of the Technical Guidance document.The equation recommended for predominantly hydrophobics is log Koc= 0.81 * log Kow+ 0.10. Using this equation log Koc value is 4.39. The theoretical partition coefficients derived from EUSES are compared to experimentally derived data in the table above. It is concluded that the empirical values vary considerably but the predictions by EUSES are within that range.Therefore the calculations were carried out with the predictions made by EUSES on the basis of log Kow.

[LogKoc: 4.39]