Registration Dossier

Administrative data

Endpoint:
adsorption / desorption
Remarks:
other: The adsorption coefficient was estimated using the specialised predictive software, PCKOCWIN, version 1.66, © 2000, U.S. Environmental Protection Agency. The software uses a molecular connectivity index (MCI) and a series of... (see attached file)
Type of information:
(Q)SAR
Adequacy of study:
supporting study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Study conducted in accordance with generally accepted scientific principles, possibly with incomplete reporting or methodological deficiencies, which do not affect the quality of relevant results.
Justification for type of information:
QSAR prediction: migrated from IUCLID 5.6

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2008

Materials and methods

Test guideline
Qualifier:
no guideline followed
GLP compliance:
yes (incl. certificate)
Type of method:
other: The adsorption coefficient was estimated using the specialised predictive software, PCKOCWIN, version 1.66, © 2000, U.S. Environmental Protection Agency. The software uses a molecular connectivity index (MCI) and a series of statistically derived fragmen
Media:
other: The adsorption coefficient was estimated using the specialised predictive software, PCKOCWIN, version 1.66, © 2000, U.S. Environmental Protection Agency. The software uses a molecular connectivity index (MCI) and a series of statistically derived fragmen

Test material

Reference
Name:
Unnamed
Type:
Constituent
Type:
Constituent
Details on test material:
Sponsor's identification : VCBK3810
Description : black powder
Lot number : N006746
Date received : 25 February 2008
Storage conditions : room temperature, in the dark

Results and discussion

Adsorption coefficient
Type:
log Koc
Value:
> 9.46
Remarks on result:
other: result obtained by using the prediction software PCKOWIN

Any other information on results incl. tables

The adsorption coefficient was estimated using the specialised predictive software, PCKOCWIN, version 1.66, © 2000, U.S. Environmental Protection Agency. The software uses a molecular connectivity index (MCI) and a series of statistically derived fragment contribution factors to apply this technique to polar compounds. The resulting calculations on inputting the proposed chemical structures are summarised in the following table:

Component Estimated Adsorption Coefficient

Log10 Koc

1 11.8

2 10.6

3 10.6

4 9.46

5 9.46

6 9.46

Although the anionic charge of the tetra-nuclear Cr(OR)4- functional group was not recognised/allocated by the software, this was considered not to impact on the validity of the estimate. This was since:

• The charge would be subject to substantial steric hindrance originating from the four surrounding aromatic rings, limiting any possible interaction with soil particles. Therefore the anionic charge was not anticipated to have a significant influence on the mobility of the test material in soils.

• Although anionic species are typically considered to be more mobile in soils than cationic species due to the ion exchange role of clay and similar particles; available literature references indicate that substances containing the similar tetra-nuclear B(OR)4- functional group persisted in soils. Borax (disodium tetraborate) containing a subunit of [B4O5(OH)4]2- was found to persist in soil for a minimum of 2 years (Tomlin CDS (editor) The Pesticide Manual, 2000, British Crop Protection Council, Surrey). Such low mobility indicates a very high adsorption coefficient. Using the PCKOCWIN predictive computer model, a log10 Koc value of 3.77 was estimated for the borax subunit. Therefore with respect to validation, the software may even potentially underestimate the adsorption coefficient of substances containing tetra-nuclear M(OR)4- functional groups. The estimated log10Koc value for the test material of interest has therefore been reported as a limit value.

• No significant hydrophilic character was observed for the test material during either the water solubility or partition coefficient determinations.

Applicant's summary and conclusion

Validity criteria fulfilled:
not specified
Conclusions:
In conclusion, using the predictive software, PCKOCWIN, version 1.66, © 2000, U.S. Environmental Protection Agency, the adsorption coefficient of the test material was estimated to be greater than log10 Koc 9.46.
Executive summary:

In conclusion, using the predictive software, PCKOCWIN, version 1.66, © 2000, U.S. Environmental Protection Agency, the adsorption coefficient of the test material was estimated to be greater than log10 Koc 9.46.