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Reference
Endpoint:
adsorption / desorption: screening
Type of information:
(Q)SAR
Adequacy of study:
key study
Study period:
2017
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
results derived from a valid (Q)SAR model and falling into its applicability domain, with adequate and reliable documentation / justification
Justification for type of information:
1. SOFTWARE
EPI Suite v4.11 Estimation Programs Interface Suite™ for Microsoft® Windows v 4.11. US EPA, United
States Environmental Protection Agency, Washington, DC, USA.
2. MODEL (incl. version number)
KOCWIN v2.00

3. SMILES OR OTHER IDENTIFIERS USED AS INPUT FOR THE MODEL
O=C(OCCO)CC(C(=O)OCCO)CP2(=O)Oc3c(c1c2cccc1)cccc3
4. SCIENTIFIC VALIDITY OF THE (Q)SAR MODEL
The following table gives statistical information for the MCI (Molecular Connectivity Index, first-order)
training and validation Datasets. The statistics pertain to the experimental log Koc and the MCI estimate
d log Koc:
MCI Methodology
Training Training Validation
No Corrections with Corrections Data set
number 69 447 158
r2corr coef 0.967 0.900 0.850
std deviation 0.247 0.340 0.583
avg deviation 0.199 0.273 0.459
The following table gives statistical information for the log Kow-based regression: training and validation
sets. The statistics pertain to the experimental log Koc and the Log Kow estimated log Koc:
Log Kow Methodology
Training Training Validation
No Corrections with Corrections Data set
number 68 447 150
r2corr coef 0.877 0.855 0.778
std deviation 0.478 0.396 0.679
avg deviation 0.371 0.307 0.494
- Defined endpoint: adsprption/desorption, Koc
- Unambiguous algorithm:
log Kow-method:
Separate equations correlating log Koc with log Kow were derived for nonpolar and polar compounds because it was statistically more accurate to do so than to use the approach taken with the MCI-based method.  The equation derived by the non-polar (no correction factor) regression is:
log Koc  =  0.8679 Log Kow  -  0.0004

    (n = 68, r2 = 0.877, std dev = 0.478, avg dev = 0.371)
For the multiple-linear regression using correction factors, log Kow was included as an individual descriptor.  For compounds having correction factors, the equation is:

 log Koc  =  0.55313 Log Kow  +  0.9251 + ΣPfN  

where ΣPfN is the summation of the products of all applicable correction factor coefficients multiplied by the number of times (N) that factor is counted for the structure.

MCI-method:
 log Koc  =  0.5213 MCI  +  0.60 + ΣPfN  

where ΣPfN is the summation of the products of all applicable correction factor coefficients multiplied by the number of times (N) that factor is counted for the structure.
- Defined domain of applicability:  
The minimum and maximum values for molecular weight are the following:

Training Set Molecular Weights:

Minimum MW:  32.04

Maximum MW:  665.02

Average MW:  224.4

 

Validation Molecular Weights:

Minimum MW:  73.14

Maximum MW:  504.12

Average MW:  277.8

 


5. ADEQUACY OF THE RESULT
The substance falls within the applicability domain described above and, therefore,
the predicted value can be considered reliable.
Qualifier:
according to
Guideline:
other: Guidance on information requirements and chemical safety assessment, Chapter R.6: QSARs and grouping of chemicals, ECHA
Deviations:
not applicable
GLP compliance:
no
Type of method:
other: QSAR
Media:
other: not applicable
Radiolabelling:
no
Details on study design: HPLC method:
Estimation software: EPISuite v 4.11, KOCWIN v2.00, MCI based method
Key result
Sample No.:
#1
Type:
Koc
Value:
10 L/kg
Temp.:
25 °C
Remarks on result:
other: MCI based method
Key result
Sample No.:
#1
Type:
log Koc
Value:
1 000 dimensionless
Temp.:
25 °C
Remarks on result:
other: MCI based method
Key result
Sample No.:
#2
Type:
Koc
Value:
0.846 L/kg
Temp.:
25 °C
Remarks on result:
other: Kow method
Key result
Sample No.:
#2
Type:
log Koc
Value:
-0.073 dimensionless
Temp.:
25 °C
Remarks on result:
other: Kow method
Transformation products:
not specified

SMILES : O=C(OCCO)CC(C(=O)OCCO)CP2(=O)Oc3c(c1c2cccc1)cccc3

CHEM   :

MOL FOR: C21 H23 O8 P1

MOL WT : 434.39

---------------------------  KOCWIN v2.00 Results  ---------------------------

 Koc Estimate from MCI:

 ---------------------

        First Order Molecular Connectivity Index  ........... : 14.481

        Non-Corrected Log Koc (0.5213 MCI + 0.60)  .......... :  8.1485

        Fragment Correction(s):

                 2   Aliphatic Alcohol  (-C-OH)  ...........  : -2.6358

                 2   Ester  (-C-CO-O-C-) or (HCO-O-C) ......  : -2.5939

                 *   OrganoPhosphorus [P=O], aromatic ......  : -2.4257

        Corrected Log Koc  .................................. :  0.4931

        Over Correction Adjustment to Lower Limit Log Koc ... :  1.0000

                        Estimated Koc:  10  L/kg   <===========

 Koc Estimate from Log Kow:

 -------------------------

        Log Kow  (Kowwin estimate)  ......................... :  0.33

        Non-Corrected Log Koc (0.55313 logKow + 0.9251)  .... :  1.1076

        Fragment Correction(s):

                 2   Aliphatic Alcohol  (-C-OH)  ...........  : -0.8229

                 2   Ester  (-C-CO-O-C-) or (HCO-O-C) ......  : -0.1312

                 *   OrganoPhosphorus [P=O], aromatic ......  : -0.2263

        Corrected Log Koc  .................................. : -0.0727

                        Estimated Koc:  0.8458  L/kg   <===========

Validity criteria fulfilled:
not applicable
Conclusions:
It can be concluded that DOP-ITS has a low Koc and is weakly sorbed and is therefore mobile in soil. The KOC value of 10 l/kg derived with EPISuite™, based on the MCI-model can be considered reliable for both modelling and environmental fate assessments.
Executive summary:

The adsorption coeffcient log Koc of DOP-ITS (Bis(2-hydroxyethyl)(6H-dibenz[c,e][1,2]oxaphosphorin-6-ylmethyl)succinate P-oxide) was determined by a non-experimental calculation method.

DOP-ITS is a slightly water soluble, organic substance.

As a slightly polar substance, it is expected that DOP-ITS would not strongly adsorb to organic matter in soil to an appreciable extent.

This is confirmed by the estimated KOC values of 10 (MCI method) and 0.85 l/kg (log Kow method).

According to the EPI SUITE User's Guide, the MCI methodology is somewhat more accurate than the Log Kow methodology, although both methods yield good results.

For risk assessment purposes the calculated Koc of 10 l/kg is used.

Description of key information

The adsorption coeffcient log Koc of DOP-ITS (Bis(2-hydroxyethyl)(6H-dibenz[c,e][1,2]oxaphosphorin-6-ylmethyl)succinate P-oxide) was determined by a non-experimental calculation method.

DOP-ITS is a slightly water soluble, organic substance.

As a slightly polar substance, it is expected that DOP-ITS would not strongly adsorb to organic matter in soil to an appreciable extent.

This is confirmed by the estimated KOC values of 10 (MCI method) and 0.85 l/kg (log Kow method).

According to the EPI SUITE User's Guide, the MCI methodology is somewhat more accurate than the Log Kow methodology, although both methods yield good results.

For risk assessment purposes the calculated Koc of 10 l/kg is used.

Key value for chemical safety assessment

Koc at 20 °C:
10

Additional information

[LogKoc: 1000.0]