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Registration Dossier
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EC number: - | CAS number: -
Adsorption / desorption
Administrative data
Link to relevant study record(s)
- Endpoint:
- adsorption / desorption: screening
- Type of information:
- calculation (if not (Q)SAR)
- Adequacy of study:
- weight of evidence
- Reliability:
- 2 (reliable with restrictions)
- Rationale for reliability incl. deficiencies:
- accepted calculation method
- Justification for type of information:
- Log Koc values of the PSE constituents of test substance were calculated using regression model equations for general and ionisable compounds. See below under 'methods' for applicability domain.
- Principles of method if other than guideline:
- The soil adsorption coefficient (Koc) values for PSE constituents of the test substance were estimated using the log Pow (Partition coefficient) correlation approach of the Log Koc regression models equations for general and ionisable compounds.
- Key result
- Type:
- log Koc
- Value:
- ca. 2.29 - ca. 2.85 dimensionless
- Remarks on result:
- other: Koc: 194.98 to 707.95 L/kg; calculated using general equations
- Key result
- Type:
- log Koc
- Value:
- ca. 2.36 - ca. 2.37 dimensionless
- Remarks on result:
- other: Koc: 229.09 to 234.42 L/kg; calculated using 'ester class' specific log Kow based regression equations
- Key result
- Type:
- log Koc
- Value:
- ca. 1.99 dimensionless
- Remarks on result:
- other: Koc: 97.72 L/kg; calculated using the ionisable compound based equation
- Validity criteria fulfilled:
- not applicable
- Conclusions:
- The log Koc of 1.99 (i.e., equivalent to Koc of 97.72 L/kg) calculated from Franco and Trapp (2008) equation has been selected as key value for this endpoint of PSE constituent.
- Executive summary:
The soil adsorption coefficient (Koc) value for the PSE constituent of the test substance, 'mono- and di- C16 PSE, K+’, were determined using the well-known log Kow based log Koc regression models equations. To calculate a more reliable value and to reduce the overall uncertainty, multiple equations, which could be categorised as general, class-specific (i.e., ester) (Doucette WJ, 2000) and ionisable compound based (Franco and Trapp, 2008), were used for the calculations. The log Koc were calculated from the equations using the log Kow value of 2.7 determined for the PSE constituent of the test substance (based on individual solubility ratio) and a maximum фn of 0.1 and a minimum фion of 0.9, for the Franco et al., equation. The log Koc values were calculated to range from 2.29 to 2.85 (i.e., equivalent to Koc: 194.98 to 707.95 L/kg), using general equations, 2.36 to 2.37 (i.e., equivalent to Koc: 229.09 to 234.42 L/kg), using ‘ester class’ specific equations, and was 1.99 using the ionisable compound based equation. This range of Koc indicates low to moderate sorption to soil / sediment and moderate to slow migration potential to ground water (US EPA, 2012). Given that the test substance is ionic, the prediction of log Koc by treating neutral and ionic fractions separately is considered superior to methods that merge both fractions without considering the differences between neutral compounds and ions (Franco and Trap, 2008). Therefore, the log Koc of 1.99 (i.e., equivalent to Koc of 97.72 L/kg) calculated from Franco and Trapp (2008) equation has been selected as key value for this endpoint of PSE constituent.
- Endpoint:
- adsorption / desorption: screening
- Type of information:
- (Q)SAR
- Adequacy of study:
- weight of evidence
- Reliability:
- 2 (reliable with restrictions)
- Rationale for reliability incl. deficiencies:
- results derived from a valid (Q)SAR model, but not (completely) falling into its applicability domain, with adequate and reliable documentation / justification
- Justification for type of information:
- QSAR prediction from a well-known and acknowledged tool. See below under ''attached background material section' for methodology and QPRF.
- Qualifier:
- according to guideline
- Guideline:
- other: REACH guidance on QSARs: Chapter R.6. QSARs and grouping of chemicals
- Principles of method if other than guideline:
- The Koc of the ester constituents of test substance was calculated using the MCI (Molecular Connectivity Index) and Kow based approaches of the KOCWIN v 2.01 program (EPISuite v 4.11). The Koc values of ester constituents were estimated using SMILES codes as the input parameter.
- Computational methods:
- The Koc of the test substance was calculated using the MCI (Molecular Connectivity Index) and Kow based approaches of the KOCWIN v 2.01 program (EPISuite v 4.11). The Koc values were estimated for ester constituents using SMILES codes as the input parameter.
- Key result
- Phase system:
- other: Estimated
- Value:
- ca. 11 700 - ca. 1 077 000 000 L/kg
- Remarks on result:
- other: MCI based method (Log Koc: 4.07 to 9.03)
- Key result
- Phase system:
- other: estimated
- Value:
- ca. 51 050 - ca. 9 810 000 000 L/kg
- Remarks on result:
- other: Kow based method (Log Koc: 4.71 to 9.99)
- Validity criteria fulfilled:
- not applicable
- Conclusions:
- The Koc values of esters constituent of the test substance using KOCWIN v 2.01 program (EPISuite v 4.11) were estimated to be 1.17E+4 to 1.08E+9 L/kg (log Koc= 1.344.07 to 9.03) wiith MCI method and 5.11E+4 to 9.81E+9 L/kg (log koc= 4.71 to 9.99) with Log Kow method.
- Executive summary:
The soil adsorption and desorption potential (Koc) of the alkyl esters constituent (linear or branched) was estimated using Molecular Connectivity Index (MCI) and Log Kow of the KOCWIN v 2.01 program (EPISuite v 4.11). Using the MCI and log Kow methods, the predicted Koc values for the constituent were estimated to be 1.17E+4 to 1.08E+9 L/kg (log Koc= 4.07 to 9.03) and 5.11E+4 to 9.81E+9 L/kg (log koc= 4.71 to 9.99), respectively. For MCI based QSAR predictions all constituents were within the descriptor domain criteria, however for Log Kow based QSAR predictions not all constituents were within the descriptor domain criteria for Log Kow. Therefore, the accuracy of the Log Kow based Koc predictions was considered to be moderate. However, the uncertainty in the accuracy of the koc predictions can be considered to be low given that: (a) The log Koc predictions follow an expected trend which is directly proportional to their log Kow values (b) Predictions from 2 methods based on different algorithms, predicts values more or less in the same range indicating a very strong adsorption potential for the ester constituents. Based on the above information, the overall ester constituents is expected to have a very strong adsorption potential (US EPA, 2012) to soil and sediment, leading to negligible migration to ground water.
- Endpoint:
- adsorption / desorption: screening
- Type of information:
- experimental study
- Adequacy of study:
- weight of evidence
- Study period:
- 2006
- Reliability:
- 2 (reliable with restrictions)
- Rationale for reliability incl. deficiencies:
- test procedure in accordance with generally accepted scientific standards and described in sufficient detail
- Qualifier:
- equivalent or similar to guideline
- Guideline:
- OECD Guideline 106 (Adsorption - Desorption Using a Batch Equilibrium Method)
- Principles of method if other than guideline:
- The radiolabelled test substance was added to a system of natural river water and activated sludge solids (sterilised with mercuric chloride). The concentration of test substance in each phase was determined by LSC following an equilibration period.
- GLP compliance:
- no
- Type of method:
- batch equilibrium method
- Media:
- sewage sludge
- Specific details on test material used for the study:
- Hexadecanol and Octadecanol uniformly radiolabeled with 14C(250 mCi of each) were obtained from American Radiolabeled Chemicals Inc. of St. Louis, MO. Radiochemical purities and specific activities determined by the manufacturer of these alcohols were 99% each for C16 and C18 alcohols and 227 and 203 mCi/g specific activities for C16 and C18 alcohol respectively.
The manufacturer indicated that radiolabeled impurities were nondetectable (pers. comm.). Each alcohol was transferred from its supply vial to a 10-mL volumetric flask with methanol. The octadecanol vial was also finally rinsed with ca. 1mL of ethyl acetate. These solutions were counted by LSC and the actual amount of each alcohol in solution was calculated. These values were compared to concentrations obtained by analysis of the solutions against unlabeled alcohols (Fluka, 97–99% purity) of the same carbon lengths by gas chromatography (GC). The ratios of the GC concentration to the LSC concentration are 0.96, and 0.86 for C16, and C18, respectively. - Radiolabelling:
- yes
- Remarks:
- See above
- Analytical monitoring:
- yes
- Details on sampling:
- Details on sampling:
- Sampling interval: 1,5,16, 30 and 72 h. - Details on matrix:
- Details on matrix:
- River water: Collected from the River Gowy, Ellesmere Port, UK on two successive days and mixed and sterilised (0.01% (m/v) mercuric chloride). It contained 12 mg/L suspended solids (SS).
- Activated sludge: Chester, U.K. (United Utilities, Sealand Road) sewage treatment works, a plant that receives mainly (>90%) domestic derived wastewater. Stirred at 150 rpm and aerated for 5 days and then mixed liquor suspended solids (MLSS) and mixed liquor volatile suspended solids (MLVSS) were determined according to Standard Methods (APHA, 1995) to be 2940 mg/L and 2210 mg/L, respectively. The total organic carbon was 880 mg/L. The mixture was sterilised and deactivated (mercuric chloride).
These two values (MLSS and TOC) result in a fraction organic carbon (foc) content of 0.299 - Details on test conditions:
- TEST CONDITIONS
- Suspended solids concentration: 30 mg SS/L.
- The TOC content of the activated sludge was 880 mg/L.
TEST SYSTEM
- Type, size and further details on reaction vessel: Four 20 ml of synthetic STP effluent from each 100 ml were pipetted into sperate 300 mL bottles for dilution with 180ml river water and agitated for the specified time period.
- Number of reaction vessels/concentration: Four replicates for each of the sampling times. 100 ± 2 ug/L radiolabelled alcohol
- Method of preparation of test solution: 4L activated sludge in 10L aspirators were spiked with stock solution of radiolabelled alcohols and stirred for 24 hours. Spiked activated slude dispensed into five 500ml bottles and gently shaken and allowed to settle for 100 minutes. 100ml subsamples taken to create five synthetic STP effluent bottles having 30 mg SS/L.
- Duration:
- 72 h
- Initial conc. measured:
- >= 98 - <= 102 other: ug/L
- Key result
- Type:
- Kd
- Value:
- 23 790 L/kg
- Matrix:
- Gowey River water suspended solids (GRW) + activated sludge
- Remarks on result:
- other: measured distribution coefficient (Kd) after 72 h, corrected for sorption onto filter
- Remarks:
- (log Kd = 4.38); foc = 0.167
- Key result
- Type:
- Koc
- Value:
- 142 492 L/kg
- Matrix:
- Gowey River water suspended solids (GRW) + activated sludge
- Remarks on result:
- other: measured sorption coefficient after 72 h
- Remarks:
- log Koc = 5.15
- Recovery of test material:
- - Sorption onto the glass fiber filter resulted in 25, and 21 % for the C16 and C18 alcohols, respectively. These values were used to correct the sorption coefficient calculations for alcohols.
- The total recovery of radioactivity from the filtrate and filters was 85, and 89 % for C16 and C18, respectively. The remainder of the radioactivity was assumed to be lost to adsorption of alcohols onto glass surfaces during the experiments.
Alcohol sorption coefficients (n ¼ 4) vs. time and carbon number, corrected for sorption onto the glass fiber filter, are shown in Table 1 (see attachment) - Transformation products:
- not measured
- Validity criteria fulfilled:
- not specified
- Conclusions:
- Under the conditions of the study, the test substance was found to show linear sorption potential, where the Kd (distribution coefficient), foc (fraction of organic carbon) for activated sludge and river water and Koc (sorption coefficient) were determined to be 23,790 L/kg (log Kd = 4.38), 0.167 and 142,490 L/kg (log Koc = 5.15) respectively.
- Executive summary:
A study was conducted to evaluate the sorption potential of test substance hexadecanol onto activated sludge and river water solids under environmentally relevant conditions. In this experiment 4L activated sludge in 10L aspirators were spiked with stock solution of radiolabelled alcohol at a final concentration of 100 ± 2 µg/L and stirred for 24 hours. Spiked activated sludge dispensed into five 500mL bottles and gently shaken and allowed to settle for 100 minutes. 100 mL subsamples were taken to create five synthetic STP effluent bottles having 30 mg SS/L. Four 20-mL volumes of synthetic STP effluent from each of the 100-mL subsamples were pipetted into separate 300-mL bottles for dilution with 180 mL of river water followed by agitation for 1, 5, 16, 30, or 72 h.It was anticipated that 72 h would be sufficient to achieve equilibrium in the samples. After the specified time the four replicates were filtered simultaneously through a 47-mm GF/C glass fiber filter under vacuum. The filter was retained for combustion and subsequent scintillation counting. The filtrate was subsampled in duplicate for scintillation counting. The emptied filtration flask, glass filtration funnel, and acrylic filter support were rinsed with methanol back into the sample bottle for estimation of amount of activity adsorbed onto these surfaces. This methanol was transferred to a scintillation vial, the methanol was evaporated, and the aqueous residue was counted by LSC. Sorption onto the glass fiber filter was determined to be 25% which was then used to correct the sorption coefficient calculations. The total recovery of radioactivity from the filtrate and filters was 85%. The remainder of the radioactivity was assumed to be lost to adsorption of alcohols onto glass surfaces during the experiments. Under the conditions of the study, the test substance was found to show linear sorption potential, where the Kd (distribution coefficient), foc (fraction of organic carbon) for activated sludge and river water and Koc (sorption coefficient) were determined to be 23,790 L/kg (log Kd = 4.38), 0.167 and 142,490 L/kg (log Koc = 5.15) respectively (Compernolle, 2006).
- Endpoint:
- adsorption / desorption: screening
- Type of information:
- read-across from supporting substance (structural analogue or surrogate)
- Adequacy of study:
- weight of evidence
- Study period:
- 2006
- Reliability:
- 2 (reliable with restrictions)
- Rationale for reliability incl. deficiencies:
- test procedure in accordance with generally accepted scientific standards and described in sufficient detail
- Justification for type of information:
- Refer to section 13 of IUCLID for details on the read-across justification.
- Reason / purpose for cross-reference:
- read-across source
- Qualifier:
- equivalent or similar to guideline
- Guideline:
- OECD Guideline 106 (Adsorption - Desorption Using a Batch Equilibrium Method)
- Principles of method if other than guideline:
- The radiolabelled test substance was added to a system of natural river water and activated sludge solids (sterilised with mercuric chloride). The concentration of test substance in each phase was determined by LSC following an equilibration period.
- GLP compliance:
- no
- Type of method:
- batch equilibrium method
- Media:
- sewage sludge
- Specific details on test material used for the study:
- Hexadecanol and Octadecanol uniformly radiolabeled with 14C(250 mCi of each) were obtained from American Radiolabeled Chemicals Inc. of St. Louis, MO. Radiochemical purities and specific activities determined by the manufacturer of these alcohols were 99% each for C16 and C18 alcohols and 227 and 203 mCi/g specific activities for C16 and C18 alcohol respectively.
The manufacturer indicated that radiolabeled impurities were nondetectable (pers. comm.). Each alcohol was transferred from its supply vial to a 10-mL volumetric flask with methanol. The octadecanol vial was also finally rinsed with ca. 1mL of ethyl acetate. These solutions were counted by LSC and the actual amount of each alcohol in solution was calculated. These values were compared to concentrations obtained by analysis of the solutions against unlabeled alcohols (Fluka, 97–99% purity) of the same carbon lengths by gas chromatography (GC). The ratios of the GC concentration to the LSC concentration are 0.96, and 0.86 for C16, and C18, respectively. - Radiolabelling:
- yes
- Remarks:
- See above
- Analytical monitoring:
- yes
- Details on sampling:
- Details on sampling:
- Sampling interval: 1,5,16, 30 and 72 h. - Details on matrix:
- Details on matrix:
- River water: Collected from the River Gowy, Ellesmere Port, UK on two successive days and mixed and sterilised (0.01% (m/v) mercuric chloride). It contained 12 mg/L suspended solids (SS).
- Activated sludge: Chester, U.K. (United Utilities, Sealand Road) sewage treatment works, a plant that receives mainly (>90%) domestic derived wastewater. Stirred at 150 rpm and aerated for 5 days and then mixed liquor suspended solids (MLSS) and mixed liquor volatile suspended solids (MLVSS) were determined according to Standard Methods (APHA, 1995) to be 2940 mg/L and 2210 mg/L, respectively. The total organic carbon was 880 mg/L. The mixture was sterilised and deactivated (mercuric chloride).
These two values (MLSS and TOC) result in a fraction organic carbon (foc) content of 0.299 - Details on test conditions:
- TEST CONDITIONS
- Suspended solids concentration: 30 mg SS/L.
- The TOC content of the activated sludge was 880 mg/L.
TEST SYSTEM
- Type, size and further details on reaction vessel: Four 20 ml of synthetic STP effluent from each 100 ml were pipetted into sperate 300 mL bottles for dilution with 180ml river water and agitated for the specified time period.
- Number of reaction vessels/concentration: Four replicates for each of the sampling times. 100 ± 2 ug/L radiolabelled alcohol
- Method of preparation of test solution: 4L activated sludge in 10L aspirators were spiked with stock solution of radiolabelled alcohols and stirred for 24 hours. Spiked activated slude dispensed into five 500ml bottles and gently shaken and allowed to settle for 100 minutes. 100ml subsamples taken to create five synthetic STP effluent bottles having 30 mg SS/L.
- Duration:
- 72 h
- Initial conc. measured:
- >= 98 - <= 102 other: ug/L
- Key result
- Type:
- Kd
- Value:
- 78 695 L/kg
- Matrix:
- Gowey River water suspended solids (GRW) + activated sludge
- Remarks on result:
- other: measured distribution coefficient (Kd) after 72 h, corrected for sorption onto filter
- Remarks:
- (log Kd = 4.9); foc = 0.167
- Key result
- Type:
- Koc
- Value:
- 471 350 L/kg
- Matrix:
- Gowey River water suspended solids (GRW) + activated sludge
- Remarks on result:
- other: measured sorption coefficient; log Koc = 5.67
- Recovery of test material:
- - Sorption onto the glass fiber filter resulted in 25, and 21 % for the C16 and C18 alcohols, respectively. These values were used to correct the sorption coefficient calculations for alcohols.
- The total recovery of radioactivity from the filtrate and filters was 85, and 89 % for C16 and C18, respectively. The remainder of the radioactivity was assumed to be lost to adsorption of alcohols onto glass surfaces during the experiments.
Alcohol sorption coefficients (n ¼ 4) vs. time and carbon number, corrected for sorption onto the glass fiber filter, are shown in Table 1 (see attachment) - Transformation products:
- not measured
- Validity criteria fulfilled:
- not specified
- Conclusions:
- Based on the results of the read across study, the constituent alcohol of the test substance was found to show linear sorption potential, where the Kd (distribution coefficient), foc (fraction of organic carbon) for activated sludge and river water and Koc (sorption coefficient) were determined to be 78,695 L/kg (log Kd = 4.9), 0.167 and 471,350 L/kg (log Koc = 5.67) respectively.
- Executive summary:
A study was conducted to evaluate the sorption potential of read across substance octadecanol onto activated sludge and river water solids under environmentally relevant conditions. In this experiment 4L activated sludge in 10 L aspirators were spiked with stock solution of radiolabelled alcohol at a final concentration of 100 ± 2 µg/L and stirred for 24 hours. Spiked activated sludge dispensed into five 500 mL bottles and gently shaken and allowed to settle for 100 minutes. 100 mL subsamples were taken to create five synthetic STP effluent bottles having 30 mg SS/L. Four 20-mL volumes of synthetic STP effluent from each of the 100-mL subsamples were pipetted into separate 300-mL bottles for dilution with 180 mL of river water followed by agitation for 1, 5, 16, 30, or 72 h.It was anticipated that 72 h would be sufficient to achieve equilibrium in the samples. After the specified time the four replicates were filtered simultaneously through a 47-mm GF/C glass fiber filter under vacuum. The filter was retained for combustion and subsequent scintillation counting. The filtrate was subsampled in duplicate for scintillation counting. The emptied filtration flask, glass filtration funnel, and acrylic filter support were rinsed with methanol back into the sample bottle for estimation of amount of activity adsorbed onto these surfaces. This methanol was transferred to a scintillation vial, the methanol was evaporated, and the aqueous residue was counted by LSC. Sorption onto the glass fiber filter was determined to be 21% which was then used to correct the sorption coefficient calculations. The total recovery of radioactivity from the filtrate and filters was 89%. The remainder of the radioactivity was assumed to be lost to adsorption of alcohols onto glass surfaces during the experiments. Under the conditions of the study, the read across substance was found to show linear sorption potential, where the Kd (distribution coefficient), foc (fraction of organic carbon) for activated sludge and river water and Koc (sorption coefficient) were determined to be 78,695 L/kg (log Kd = 4.9), 0.167 and 471,350 L/kg (log Koc = 5.67) respectively (Compernolle, 2006). Based on the results of the read across study, a similar log Koc can be expected for the constituent alcohol.
Referenceopen allclose all
Results
Koc was calculated using range of regression equations, i.e., ester class specific, general wide variety and ionisable coumpound specific. The test substance is a phosphate ester, therefore the equations related to ester class have been selected as one the criteria to generate the Koc value for the test substance. Apart from chemical class specific equations, general equations also have selected due to their well documented development and large data sets of Koc values. As the test substance is ionisable substance, the regression equation for ionisable compound also used to calculate the Koc. Prediction of log Koc can be improved by treating neutral and ionic fractions separately and therefore probably is superior to methods that merge both fractions without considering the differences between neutral compounds and ions. pKa values of the PSEs are expected to be between 1.5 and 3, the mono-esters will have lower pKas (i.e. higher acidity), the di-esters higher ones. The interval with a maximum фn = 0.1 and a minimum фion = 0.9 is therefore likely to comprise all PSEs having an acidic OH-Group (mono- and di-esters).
Log Kow value of the PSEs:
The log Kow of the entire test substance including all the constituents was determined to be 0.85. Since, the log Kow corresponding to only the PSE constituents is needed and QSAR modelling is not suitable as these components are ionic, a read across approach was explored. The following structurally similar substances with experimental log Kow were identified:
1. Phosphoric acid, hexadecyl esters, potassium salts with cetyl alcohol and isostearyl isostearate' (containing 5-15% mono PSE; 10 -20% of di PSE, 30 -50% of hexadecanol and 25 -40% of isostearyl isostearate) was determined to have a log Kow of 2.7at 20°C (calculated based on solubility ratio).
2. Reaction mass of mono- and di- hexadecyl phosphate esters, potassium salts and phosphoric acid (containing 50-70% of mono PSE, 5-15% of di PSE and 10-20% of phosphoric acid) was determined to have a log Kow of 0.189 at 20°C (calculated based on solubility ratio).
Although the second read across substance is a closer substance having higher amount of PSE component, the higher log Kow of the first substance, ‘Phosphoric acid, hexadecyl esters, potassium salts with cetyl alcohol and isostearyl isostearate’ has been considered for the log Koc calculations for PSE constituents, as a conservative approach.
Table 1: Calculations of Koc based on regression models equations (General and Ionisable Compound)
Regression Models Used to Estimate Log Koc from Log Kow |
||
|
Ǿneutral fraction |
0.1 |
|
Ǿionic fraction |
0.9 |
Equation Number |
Log Kow |
|
2.7 (based on read across) |
|
|
(I) |
EPISuite (Doucette, 2000) |
Log Koc = 0.8679 Log Kow - 0.0004 |
|
Log Koc |
2.34 |
(II) |
Variety, mostly pesticides (Kenaga and Goring, 1980) |
log Koc = = 1.377 + 0.544 log Kow |
|
Log Koc |
2.85 |
(III) |
Ester Class specific (Sabljic et al 1995) |
log Koc = 0.47 log Kow + 1.09 |
|
Log Koc |
2.36 |
(IV) |
Wide variety (Gerstl, 1990) |
log Koc = 0.679 log Kow + 0.663 |
|
Log Koc |
2.50 |
(V) |
Hydrophobics (Sabljic et al 1995) |
log Koc = 0.81 log Kow + 0.10 |
|
Log Koc |
2.29 |
(VI) |
Wide variety (Baker et al 1997) |
log Koc = 0.903 log Kow + 0.094 |
|
Log Koc |
2.53 |
(VII) |
Franco and Trapp (2008) |
Log Koc = Log (Ǿn*10^(0.54 log Kow + 1.11) + Ǿion*10^(0.11 log Kow + 1.54)) |
|
Log Koc |
1.99 |
(VIII) |
Esters class specific (EC, 2003) |
Log Koc = 0.49 log Kow + 1.05 |
|
Log Koc |
2.37 |
Franco and Trapp 2008 |
Equa. (VII) |
1.99 |
Average of all log Koc values |
Equa. (I) + (II) + (III) + (IV) + (V) + (VI) + (VIII) |
2.46 |
Selected Log Koc value |
|
1.99 |
|
KOC |
97.72 |
The log Koc of 1.99 (i.e., equivalent to Koc of 97.72 L/kg) calculated from Franco and Trapp (2008) equation has been selected as key value for this endpoint of PSE constituent.
Predicted value:
The estimated Koc values for the ester constituents using MCI and log Kow methods were as follows:
Table 1: Koc predictions: MCI method
Constituents group |
Name |
SMILES |
EPISuite |
Log Koc - MCI |
Domain evaluation |
Ester |
Stearic acid/potassium stearate |
CCCCCCCCCCCCCCCCCC(=O)O |
1.17E+04 |
4.07 |
In domain: Molecular weight and molecular fragments |
Cetyl stearate |
CCCCCCCCCCCCCCCCCC(=O)O(CCCCCCCCCCCCCCCC) |
3.86E+08 |
8.59 |
In domain: Molecular weight and molecular fragments |
|
Cetyl Isostearate |
CC(C)CCCCCCCCCCCCCCC(=O)O(CCCCCCCCCCCCCCCC) |
3.24E+08 |
8.51 |
In domain: Molecular weight and molecular fragments |
|
Isostearyl Isostearate |
CC(C)CCCCCCCCCCCCCCC(=O)O(CCCCCCCCCCCCCCCC(C)C) |
9.06E+08 |
8.96 |
In domain: Molecular weight and molecular fragments |
|
Isostearyl stearate |
CC(C)CCCCCCCCCCCCCCCOC(=O)CCCCCCCCCCCCCCCCC |
1.08E+09 |
9.03 |
In domain: Molecular weight and molecular fragments |
|
|
|
Range |
1.17E+4 to 1.08E+9 |
4.07 to 9.03 |
|
Table 2: Koc predictions: Log Kow-based method
Constituents group |
Name |
SMILES |
EPISuite |
Log Koc - MCI |
Domain evaluation |
Ester |
Stearic acid/potassium stearate |
CCCCCCCCCCCCCCCCCC(=O)O |
5.11E+04 |
4.71 |
In domain: Molecular weight and molecular fragments, Log Kow - Experimental |
Cetyl stearate |
CCCCCCCCCCCCCCCCCC(=O)O(CCCCCCCCCCCCCCCC) |
3.08E+09 |
9.49 |
In domain: Molecular weight and molecular fragments; Out domain: Log Kow |
|
Cetyl Isostearate |
CC(C)CCCCCCCCCCCCCCC(=O)O(CCCCCCCCCCCCCCCC) |
2.78E+09 |
9.44 |
In domain: Molecular weight and molecular fragments; Out domain: Log Kow |
|
Isostearyl Isostearate |
CC(C)CCCCCCCCCCCCCCC(=O)O(CCCCCCCCCCCCCCCC(C)C) |
8.86E+09 |
9.95 |
In domain: Molecular weight and molecular fragments; Out domain: Log Kow |
|
Isostearyl stearate |
CC(C)CCCCCCCCCCCCCCCOC(=O)CCCCCCCCCCCCCCCCC |
9.81E+09 |
9.99 |
In domain: Molecular weight and molecular fragments; Out domain: Log Kow |
|
|
|
Range |
5.11E+4 to 9.81E+9 |
4.71 to 9.99 |
|
Koc predicted results:
| SMILES : CCCCCCCCCCCCCCCCCC(=O)O | ||
| MOL FOR: C18 H36 O2 | Domain evaluation | MW (Training set) |
| MW: 284.49 | ID | 665.02 |
| Koc may be sensitive to pH! | ||
| --------------------------- KOCWIN v2.01 Results --------------------------- | ||
| Koc Estimate from MCI: | ||
| --------------------- | ||
| First Order Molecular Connectivity Index ........... : 9.770 | ||
| Non-Corrected Log Koc (0.5213 MCI + 0.60) .......... : 5.6929 | ||
| Fragment Correction(s): | ||
| * Organic Acid (-CO-OH) ............... : -1.6249 | ID | 1 |
| Corrected Log Koc .................................. : 4.0681 | ||
| Estimated Koc: 1.17e+004 L/kg <=========== | ||
| Koc Estimate from Log Kow: | ||
| ------------------------- | ||
| Log Kow (experimental DB) ......................... : 8.23 | Experimental | |
| Non-Corrected Log Koc (0.55313 logKow + 0.9251) .... : 5.4774 | ||
| Fragment Correction(s): | ||
| * Organic Acid (-CO-OH) ............... : -0.7694 | ||
| Corrected Log Koc .................................. : 4.7080 | ||
| Estimated Koc: 5.105e+004 L/kg <=========== | ||
| ******************************************************************** | ||
| * NOTE: * | ||
| * The Koc of this structure may be sensitive to pH! The estimated * | ||
| * Koc represents a best-fit to the majority of experimental values * | ||
| * however, the Koc may vary significantly with pH. * | ||
| ******************************************************************** | ||
| SMILES : CCCCCCCCCCCCCCCCCC(=O)O(CCCCCCCCCCCCCCCC) | ||
| CHEM : | ||
| MOL FOR: C34 H68 O2 | Domain evaluation | MW (Training set) |
| MOL WT : 508.92 | ID | 665.02 |
| --------------------------- KOCWIN v2.01 Results --------------------------- | ||
| Koc Estimate from MCI: | ||
| --------------------- | ||
| First Order Molecular Connectivity Index ........... : 17.808 | ||
| Non-Corrected Log Koc (0.5213 MCI + 0.60) .......... : 9.8831 | ||
| Fragment Correction(s): | ||
| 1 Ester (-C-CO-O-C-) or (HCO-O-C) ...... : -1.2970 | ID | 2 |
| Corrected Log Koc .................................. : 8.5862 | ||
| Estimated Koc: 3.856e+008 L/kg <=========== | ||
| Koc Estimate from Log Kow: | ||
| ------------------------- | ||
| Log Kow (Kowwin estimate) ......................... : 15.60 | OD | 1.19-9.1 |
| Non-Corrected Log Koc (0.55313 logKow + 0.9251) .... : 9.5539 | ||
| Fragment Correction(s): | ||
| 1 Ester (-C-CO-O-C-) or (HCO-O-C) ...... : -0.0656 | ||
| Corrected Log Koc .................................. : 9.4883 | ||
| Estimated Koc: 3.078e+009 L/kg <=========== | ||
| SMILES : CC(C)CCCCCCCCCCCCCCC(=O)O(CCCCCCCCCCCCCCCC) | ||
| CHEM : | ||
| MOL FOR: C34 H68 O2 | Domain evaluation | MW (Training set) |
| MOL WT : 508.92 | ID | 665.02 |
| --------------------------- KOCWIN v2.01 Results --------------------------- | ||
| Koc Estimate from MCI: | ||
| --------------------- | ||
| First Order Molecular Connectivity Index ........... : 17.664 | ||
| Non-Corrected Log Koc (0.5213 MCI + 0.60) .......... : 9.8080 | ||
| Fragment Correction(s): | ||
| 1 Ester (-C-CO-O-C-) or (HCO-O-C) ...... : -1.2970 | ID | 2 |
| Corrected Log Koc .................................. : 8.5110 | ||
| Estimated Koc: 3.244e+008 L/kg <=========== | ||
| Koc Estimate from Log Kow: | ||
| ------------------------- | ||
| Log Kow (Kowwin estimate) ......................... : 15.52 | OD | 1.19-9.1 |
| Non-Corrected Log Koc (0.55313 logKow + 0.9251) .... : 9.5097 | ||
| Fragment Correction(s): | ||
| 1 Ester (-C-CO-O-C-) or (HCO-O-C) ...... : -0.0656 | ||
| Corrected Log Koc .................................. : 9.4441 | ||
| Estimated Koc: 2.78e+009 L/kg <=========== | ||
| SMILES : CC(C)CCCCCCCCCCCCCCC(=O)O(CCCCCCCCCCCCCCCC(C)C) | ||
| CHEM : | ||
| MOL FOR: C36 H72 O2 | Domain evaluation | MW (Training set) |
| MOL WT : 536.97 | ID | 665.02 |
| --------------------------- KOCWIN v2.01 Results --------------------------- | ||
| Koc Estimate from MCI: | ||
| --------------------- | ||
| First Order Molecular Connectivity Index ........... : 18.520 | ||
| Non-Corrected Log Koc (0.5213 MCI + 0.60) .......... : 10.2541 | ||
| Fragment Correction(s): | ||
| 1 Ester (-C-CO-O-C-) or (HCO-O-C) ...... : -1.2970 | ID | 2 |
| Corrected Log Koc .................................. : 8.9572 | ||
| Estimated Koc: 9.061e+008 L/kg <=========== | ||
| Koc Estimate from Log Kow: | ||
| ------------------------- | ||
| Log Kow (Kowwin estimate) ......................... : 16.43 | OD | 1.19-9.1 |
| Non-Corrected Log Koc (0.55313 logKow + 0.9251) .... : 10.0130 | ||
| Fragment Correction(s): | ||
| 1 Ester (-C-CO-O-C-) or (HCO-O-C) ...... : -0.0656 | ||
| Corrected Log Koc .................................. : 9.9474 | ||
| Estimated Koc: 8.86e+009 L/kg <=========== | ||
| SMILES : CC(C)CCCCCCCCCCCCCCCOC(=O)CCCCCCCCCCCCCCCCC | ||
| CHEM : | ||
| MOL FOR: C36 H72 O2 | Domain evaluation | MW (Training set) |
| MOL WT : 536.97 | ID | 665.02 |
| --------------------------- KOCWIN v2.01 Results --------------------------- | ||
| Koc Estimate from MCI: | ||
| --------------------- | ||
| First Order Molecular Connectivity Index ........... : 18.664 | ||
| Non-Corrected Log Koc (0.5213 MCI + 0.60) .......... : 10.3293 | ||
| Fragment Correction(s): | ||
| 1 Ester (-C-CO-O-C-) or (HCO-O-C) ...... : -1.2970 | ID | 2 |
| Corrected Log Koc .................................. : 9.0323 | ||
| Estimated Koc: 1.077e+009 L/kg <=========== | ||
| Koc Estimate from Log Kow: | ||
| ------------------------- | ||
| Log Kow (Kowwin estimate) ......................... : 16.51 | OD | 1.19-9.1 |
| Non-Corrected Log Koc (0.55313 logKow + 0.9251) .... : 10.0573 | ||
| Fragment Correction(s): | ||
| 1 Ester (-C-CO-O-C-) or (HCO-O-C) ...... : -0.0656 | ||
| Corrected Log Koc .................................. : 9.9917 | ||
| Estimated Koc: 9.81e+009 L/kg <=========== |
Description of key information
Based on the available weight of evidence information from the read across studies of the main constituents, the test substance, is considered to be highly adsorbing with log Koc >5.
Key value for chemical safety assessment
- Koc at 20 °C:
- 100 000
Additional information
In absence of adsorption study with the test substance, the endpoint has been assessed based on studies for read across substances representative of the main constituents, which can be categorised as phosphate esters (PSE i.e., mono- and di C16 PSE, K+: 10 -40%), alkyl esters (i.e., C16-18 linear and branched fatty acid esters: 39 -87%) and alcohols (i.e., C16 -18 linear or branched alcohol: 10 -30%). The results are presented below:
Constituent: PSE
Study 1: The soil adsorption coefficient (Koc) value for the PSE constituent of the test substance, 'mono- and di- C16 PSE, K+ and C16-OH and isostearyl isostearate’, were determined using the well-known log Kow based log Koc regression models equations. To calculate a more reliable value and to reduce the overall uncertainty, multiple equations, which could be categorised as general, class-specific (i.e., ester) (Doucette WJ, 2000) and ionisable compound based (Franco and Trapp, 2008), were used for the calculations. The log Koc were calculated from the equations using the log Kow value of 2.7 determined for the PSE constituent of the test substance (based on individual solubility ratio) and a maximum фn of 0.1 and a minimum фion of 0.9, for the Franco et al., equation. The log Koc values were calculated to range from 2.29 to 2.85 (i.e., equivalent to Koc: 194.98 to 707.95 L/kg), using general equations, 2.36 to 2.37 (i.e., equivalent to Koc: 229.09 to 234.42 L/kg), using ‘ester class’ specific equations, and was 1.99 using the ionisable compound based equation. This range of Koc indicates low to moderate sorption to soil / sediment and moderate to slow migration potential to ground water (US EPA, 2012). Given that the test substance is ionic, the prediction of log Koc by treating neutral and ionic fractions separately is considered superior to methods that merge both fractions without considering the differences between neutral compounds and ions (Franco and Trap, 2008). Therefore, the log Koc of 1.99 (i.e., equivalent to Koc of 97.72 L/kg) calculated from Franco and Trapp (2008) equation has been selected as key value for this endpoint of PSE constituent.
Constituent: Alkyl esters - Estimated
The soil adsorption and desorption potential (Koc) of the alkyl esters constituent (linear or branched) was estimated using Molecular Connectivity Index (MCI) and Log Kow of the KOCWIN v 2.01 program (EPISuite v 4.11). Using the MCI and log Kow methods, the predicted Koc values for the constituent were estimated to be 1.17E+4 to 1.08E+9 L/kg (log Koc= 4.07 to 9.03) and 5.11E+4 to 9.81E+9 L/kg (log koc= 4.71 to 9.99), respectively. For MCI based QSAR predictions all constituents were within the descriptor domain criteria, however for log Kow based QSAR predictions not all constituents were within the descriptor domain criteria for log Kow. Therefore, the accuracy of the log Kow based Koc predictions was considered to be moderate. However, the uncertainty in the accuracy of the koc predictions can be considered to be low given that: (a) The log Koc predictions follow an expected trend which is directly proportional to their log Kow values (b) Predictions from 2 methods based on different algorithms, predicts values more or less in the same range indicating a very strong adsorption potential for the ester constituents. Based on the above information, the overall ester constituents is expected to have a very strong adsorption potential (US EPA, 2012) to soil and sediment, leading to negligible migration to ground water.
Constituent: Alcohol
A study was conducted to evaluate the sorption potential of test substance hexadecanol onto activated sludge and river water solids under environmentally relevant conditions. In this experiment 4L activated sludge in 10L aspirators were spiked with stock solution of radiolabelled alcohol at a final concentration of 100 ± 2 µg/L and stirred for 24 hours. Spiked activated sludge dispensed into five 500mL bottles and gently shaken and allowed to settle for 100 minutes. 100 mL subsamples were taken to create five synthetic STP effluent bottles having 30 mg SS/L. Four 20-mL volumes of synthetic STP effluent from each of the 100-mL subsamples were pipetted into separate 300-mL bottles for dilution with 180 mL of river water followed by agitation for 1, 5, 16, 30, or 72 h.It was anticipated that 72 h would be sufficient to achieve equilibrium in the samples. After the specified time the four replicates were filtered simultaneously through a 47-mm GF/C glass fiber filter under vacuum. The filter was retained for combustion and subsequent scintillation counting. The filtrate was subsampled in duplicate for scintillation counting. The emptied filtration flask, glass filtration funnel, and acrylic filter support were rinsed with methanol back into the sample bottle for estimation of amount of activity adsorbed onto these surfaces. This methanol was transferred to a scintillation vial, the methanol was evaporated, and the aqueous residue was counted by LSC. Sorption onto the glass fiber filter was determined to be 25% which was then used to correct the sorption coefficient calculations. The total recovery of radioactivity from the filtrate and filters was 85%. The remainder of the radioactivity was assumed to be lost to adsorption of alcohols onto glass surfaces during the experiments. Under the conditions of the study, the test substance was found to show linear sorption potential, where the Kd (distribution coefficient), foc (fraction of organic carbon) for activated sludge and river water and Koc (sorption coefficient) were determined to be 23,790 L/kg (log Kd = 4.38), 0.167 and 142,490 L/kg (log Koc = 5.15) respectively (Compernolle, 2006).
Constituent: Alcohol - read across study
A study was conducted to evaluate the sorption potential of read across substance octadecanol onto activated sludge and river water solids under environmentally relevant conditions. In this experiment 4L activated sludge in 10 L aspirators were spiked with stock solution of radiolabelled alcohol at a final concentration of 100 ± 2 µg/L and stirred for 24 hours. Spiked activated sludge dispensed into five 500 mL bottles and gently shaken and allowed to settle for 100 minutes. 100 mL subsamples were taken to create five synthetic STP effluent bottles having 30 mg SS/L. Four 20-mL volumes of synthetic STP effluent from each of the 100-mL subsamples were pipetted into separate 300-mL bottles for dilution with 180 mL of river water followed by agitation for 1, 5, 16, 30, or 72 h.It was anticipated that 72 h would be sufficient to achieve equilibrium in the samples. After the specified time the four replicates were filtered simultaneously through a 47-mm GF/C glass fiber filter under vacuum. The filter was retained for combustion and subsequent scintillation counting. The filtrate was subsampled in duplicate for scintillation counting. The emptied filtration flask, glass filtration funnel, and acrylic filter support were rinsed with methanol back into the sample bottle for estimation of amount of activity adsorbed onto these surfaces. This methanol was transferred to a scintillation vial, the methanol was evaporated, and the aqueous residue was counted by LSC. Sorption onto the glass fiber filter was determined to be 21% which was then used to correct the sorption coefficient calculations. The total recovery of radioactivity from the filtrate and filters was 89%. The remainder of the radioactivity was assumed to be lost to adsorption of alcohols onto glass surfaces during the experiments. Under the conditions of the study, the read across substance was found to show linear sorption potential, where the Kd (distribution coefficient), foc (fraction of organic carbon) for activated sludge and river water and Koc (sorption coefficient) were determined to be 78,695 L/kg (log Kd = 4.9), 0.167 and 471,350 L/kg (log Koc = 5.67) respectively (Compernolle, 2006).
Overall, based on the weight of evidence from studies for substances representing the main constituents and the fact that the constituent alkyl esters, make up more than 80% of the composition, the test substance, ‘Reaction products of hexadecyl dihydrogen phosphate, dihexadecyl hydrogen phosphate, hexadecan-1-ol, stearic acid, esters of C18 (branched and linear) fatty acids with C18 (branched and linear) alcohols, and potassium hydroxide’ can be considered to be highly adsorbing with Log Koc values >5.
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