Charcoal, coconut shell

Partition coefficient

Description of key information

The Partition coefficient of the Water Accommodated Fraction of Coconut shell charcoal has been determined using a standard flask method. The logKow was found to be <1.2.
Supporting tests (‘worst case’ approach) show that the WAF will not contain molecules which will individually have a log Kow value over 1.2.
The logKow values found do not lead to concern for bioaccumulation. 

Key value for chemical safety assessment

Log Kow (Log Pow):

-1.4

at the temperature of:

20 °C

Additional information

The results are shown in the table.

 

		Absorbance at (nm)
Source	Layer	300	350	400	450	500
WAF   (Water Accommodated Fraction)	eq. water layer	1.91	1.40	1.12	0.955	0.865
	eq. water blank	0.105	0.052	0.033	0.033	0.024
	eq. water layer, nett	1.805	1.348	1.087	0.922	0.841
	eq. octanol layer	0.171	0.105	0.086	0.081	0.062
	eq. octonol blank	0.105	0.052	0.038	0.033	0.019
	eq. octanol layer, nett	0.066	0.053	0.048	0.048	0.043
	Kow	0.037	0.039	0.044	0.052	0.051
	log Kow	-1.4	-1.4	-1.4	-1.3	-1.3
OAF   (Octanol Accommodated Fraction)	eq. water layer	0.276	0.152	0.119	0.109	0.100
	eq. water blank	0.105	0.052	0.033	0.033	0.024
	eq. water layer, nett	0.171	0.1	0.086	0.076	0.076
	eq. octanol layer	2.92	0.869	0.335	0.2	0.114
	eq. octanol blank	0.105	0.052	0.038	0.033	0.019
	eq. octanol layer, nett	2.82	0.817	0.297	0.167	0.095
	Kow	16.5	8.2	3.5	2.2	1.3
	log Kow	1.2	0.9	0.5	0.3	0.1

 

 

 

The logKow values for the WAF (Water Accommodated Fraction) of the substance is found to be -/- 1.4 (negative).

 

The log Kow of the WAF is practically independent from the wavelength at which the determination is made. The WAF is thus found to be consistently hydrophilic. This value does not lead to concern for bioaccumulation.

 

The logKow values for the OAF (Octanol Accommodated Fraction) of the substance is found to range from 1.2 to 0.1, depending of the wavelength used. It can be concluded that the OAF consists of a range of molecules, whereby the more conjugated molecules are more hydrophilic than the less conjugated molecules.

 

As per the Guidance (Guidance on information requirements and chemical safety assessment, Chapter R.7c: Endpoint specific guidance, chapter R.7.10.5.), organic substances with log Kow below 3 are generally assumed not to be significantly bioaccumulative.

 

The OAF can be seen as an overestimation of the worst case for the molecules present in the WAF. The highest value of log Kow found for the OAF (1.2) does still not at all lead to concern for bioaccumulation.