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Endpoint:
adsorption / desorption: screening
Type of information:
(Q)SAR
Adequacy of study:
key study
Study period:
2013
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Use of valid QSAR
Justification for type of information:
QSAR prediction: migrated from IUCLID 5.6
Qualifier:
according to guideline
Guideline:
other: TGD QSARs for soil and sediment sorption for different chemical classes
GLP compliance:
no
Type of method:
other: QSAR estimation
Computational methods:
Log Koc was calculated from Log Kow according to equations defined by Sabljic and Güsten (1995) for non hydrophobic substances as reported in the TGD, 2003:
LogKoc = 0.52 logKow + 1.02
Type:
log Koc
Value:
3.355
Validity criteria fulfilled:
yes
Conclusions:
The Log Koc of the substance predicted from Log Kow of 4.491 and following equations of Sabljic and Güsten (1995) for non hydrophobic substances is 3.355 which gives a Koc of 2266 L/kg.
Endpoint:
adsorption / desorption: screening
Type of information:
experimental study
Adequacy of study:
key study
Study period:
From 2013-07-15 to 2013-08-03
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Justification for type of information:
Not applicable.
Qualifier:
according to guideline
Guideline:
OECD Guideline 106 (Adsorption - Desorption Using a Batch Equilibrium Method)
Deviations:
no
Principles of method if other than guideline:
Not applicable.
GLP compliance:
yes (incl. QA statement)
Remarks:
Signed on April 2013
Type of method:
batch equilibrium method
Media:
soil/sewage sludge
Specific details on test material used for the study:
None.
Radiolabelling:
no
Test temperature:
21.5 ± 2 °C
Details on study design: HPLC method:
Not applicable.
Analytical monitoring:
yes
Details on sampling:
Adsorption:
All test tubes were shaken horizontally on a rotary shaker at 180 to 210 strokes per minute. The agitation device kept the soil in suspension during shaking. After shaking, the samples were centrifuged (15 minutes at 6000 rpm (25 mL, teflon tubes), 31 minutes at 3400 rpm (25 mL, glass tubes) or for 40 minutes at 2200 rpm (100 mL, glass tubes)); cetrifugation conditions were suitable to remove particles larger than 0.2 μm from the solution) and the supernatants decanted into tared, labeled sample containers. The volumes of the supernatants were determined gravimetrically. At the different sampling intervals (48h during ratio-finding, 2, 5, 24 and 48h during kinetics test), the samples were removed for LC-MS/MS analysis for determination of the test item concentration.
The equilibrium concentration of the test item, and its total amount in the aqueous phase, were calculated based on the results of the analyses. The amount of test item sorbed to soil particles was obtained from the difference between the initial and final amount of test item in the aqueous phase.

Kinetic tests:
After 2, 5, 24 and 48 hours of shaking during the adsorption phase, duplicate tubes were sampled (serial method) and the supernatants analysed by LC-MS/MS after 1:100 dilution with water/methanol/HFO, 70/30/0.5, v/v/v. The distribution coefficients for adsorption Kd and Koc were determined after 48 hours of contact.

Mass balance:
The mass balance was carried out on all soils in duplicate after the 48-hour adsorption step in the kinetics test. After sampling, the supernatant was removed and remaining analytes were extracted from soil with once 20 mL methanol/water (1/4, v/v) and twice 10 mL of methanol/water (4:1; v/v) for about 30 min. The extracts from the same tube were combined and analysed by LC-MS/MS after dilution with water/methanol/HFO, 70/30/0.5, v/v/v (1:200 for soil I, IV, V and 1:50 soil II and soil III in kinetics test A; 1:100 for all samples of kinetics test B).
Matrix no.:
#1
Matrix type:
clay
% Clay:
40.6
% Silt:
37
% Sand:
22.4
% Org. carbon:
1.66
pH:
7.1
CEC:
23 meq/100 g soil d.w.
Matrix no.:
#2
Matrix type:
sand
% Clay:
3.48
% Silt:
5.04
% Sand:
91.48
% Org. carbon:
0.92
pH:
6.23
CEC:
8.08 meq/100 g soil d.w.
Matrix no.:
#3
Matrix type:
loam
% Clay:
17.82
% Silt:
44.35
% Sand:
37.83
% Org. carbon:
1.19
pH:
7.01
CEC:
12.33 meq/100 g soil d.w.
Matrix no.:
#4
Matrix type:
other: Acivated sludge from Municipal Wastewater treatment plant
% Org. carbon:
30.79
pH:
6.41
CEC:
92 meq/100 g soil d.w.
Matrix no.:
#5
Matrix type:
other: Acivated sludge from Municipal Wastewater treatment plant
% Sand:
>= 6.36 - <= 6.5
% Org. carbon:
>= 27.88 - <= 30.26
pH:
>= 6.36 - <= 6.5
CEC:
>= 88.18 - <= 95.27 meq/100 g soil d.w.
Details on matrix:
COLLECTION AND STORAGE
The soils were collected from different agricultural areas. Sampling and handling of the soils were performed under consideration of ISO 10381-6 “(Soil Quality-Sampling-Guidance on the collection, handling and storage of soil for the assessment of microbial processes in the laboratory)”.
Soil I (Speyer 6S) was sampled from the top 20 cm layer from an agricultural area in Siebeldingen (Germany, 49° 12’ N, 8° 03’ E) in January 2011. The soil has not been fertilized or treated with pesticides for at least three years prior to sampling.
Soil II (Stolpe) was sampled the top 20 cm layer from an agricultural area in Stolpe (Germany, 52° 39’ N, 13° 16’ E) in June 2010. The soil has not been fertilized or treated with pesticides for at least three years prior to sampling.
Soil III (Mechtildshausen) was sampled from the top 20 cm layer from an agricultural area in Mechtildshausen (Germany; 50°02’ N, 8° 18’ E) in May 2011. The soil has not been fertilized or treated with pesticides for at least three years prior to sampling.
The sewage sludges were obtained from the municipal sewage treatment plant ARA (Abwasserreinigungsanlage) Sissach (Basel, Switzerland) and ARA Füllinsdorf (Switzerland). The collected sludges were allowed to settle before the supernatant was decanted. The settled solids were washed two times with tap water. Thereafter, the sludges were lyophilised and the resulting solid was crushed to a dry powder.
All soils and sludges were sieved to 2 mm by Harlan Laboratories Ltd. before use.
In order to eliminate microbial degradation of the test item, the soils/sediment were sterilized before use by γ-irradiation (Studer Hard, 4658 Däniken / Switzerland).

SOIL/SLUDGE PREPARATION AND CONDITIONING
The soils, sieved to 2-mm, were air-dried at room temperature and homogenized. Disaggregation was performed with minimal force, so that the original texture of the soil was changed as little as possible. Thereafter, the soil moisture content was determined by heating three soil aliquots in a halogen drier until there was no significant change in weight. The same moisture analysis was done for the sludges.
The soil and sludge samples were pre-equilibrated with about 95% of the targeted volume of the aqueous phase by shaking for at least 12 hours at 20 °C prior to application of the test item.
Details on test conditions:
TEST CONDITIONS
Tubes and Experimental Conditions
The study was performed in Teflon or glass centrifuge tubes. All experiments including controls were performed in duplicate and at a constant temperature of 21.5 ± 2 °C. The tubes were shaken in the dark at 180 to 210 strokes per minute. The agitation device kept the soil in suspension during shaking.

Stock solution
An aliquot of 5 g of the test item was transferred into a volumetric flask and dissolved in water to a final concentration of 54.6 a.i. g/L for the ratio finding test considering the purity of 54.6%. Aliquots of 0.55 g and 2.75 g were dissolved in 50 mL water to provide stock solutions of 6.01 a.i. g/L and 30.0 a.i. g/L for the kinetic tests A and B, respectively.

Application solution
For the application solution of the ratio finding test, 2.75 mL of the stock solution were diluted in 0.01 M CaCl2 solution to a total volume of 100 mL and a final concentration of 1.5 g/L.
For the kinetic test A and B the prepared stock solutions were used as application solution.

Calibration solutions
All calibration solutions were prepared in water/methanol/formic acid/0.01 M CaCl2, 70/30/0.5/1, v/v/v/v to match initial LC conditions and (1:100) diluted samples.

Ratio finding test:
Dilution St.2 was prepared by dissolving 1 mL of stock solution in a total volume of 100 mL of water/methanol/formic acid/0.01 M CaCl2, 70/30/0.5/1, v/v/v/v to a concentration of 546 mg/L. Dilution St.3 was prepared by dissolving 1 mL of St. 2 in a total volume of 100 mL of water/methanol/formic acid/0.01 M CaCl2, 70/30/0.5/1, v/v/v/v to a concentration of 5.5 mg/L.

Kinetics test A:
Dilution St.2 was prepared by dissolving 1 mL of stock solution in a total volume of 100 mL of water/methanol/formic acid/0.01 M CaCl2, 70/30/0.5/1, v/v/v/v to a concentration of 6.01 mg/L. Dilution St.3 was prepared by dissolving 1 mL of St. 2 in a total volume of 100 mL of water/methanol/formic acid/0.01 M CaCl2, 70/30/0.5/1, v/v/v/v to a concentration of 0.06 mg/L.

Kinetics test B:
Dilution St.2 was prepared by dissolving 1 mL of stock solution in a total volume of 100 mL of water/methanol/formic acid/0.01 M CaCl2, 70/30/0.5/1, v/v/v/v to a concentration of 30.04 mg/L. Dilution St.3 was prepared by dissolving 1 mL of St. 2 in a total volume of 100 mL of water/methanol/formic acid/0.01 M CaCl2, 70/30/0.5/1, v/v/v/v to a concentration of 0.30 mg/L.

APPLICATION
After pre-equilibration of the soil with 0.01 M CaCl2 solution, aliquots of the corresponding application solutions were added on the surface of the supernatant.
Following application, all test tubes were shaken on a rotary shaker in a temperature-controlled room for the respective experimental period.
Besides the treated samples, controls (duplicates, without soil) and blanks (duplicates, without test item) were subjected to precisely the same steps as the test samples. The control samples checked the stability of the test item in CaCl2 solution whereas the blanks served as a background control during the analysis to detect interfering compounds or contaminated soils.

Test Concentrations
The initial test concentrations of the ratio finding test were approximately 6.24 mg/L for C10-0, 28.3 mg/L for C12-0 and 2.76 mg/L for C18-1. The respective approximate initial concentrations in the kinetics test A were 10.0 mg/L for C10-0, 45.4 mg/L for C12-0 and in kinetics test B 13.8 mg/L for C18-1. The exact values were determined by application controls. Along with application of the test tubes, triplicate aliquots of each application volume (0.4 and 1.0 mL, corresponding to the application volume in the batch systems) were spiked into volumetric flasks and filled to a final volume of 10, 25 or 100 mL. Each of these application controls was then treated as a sample and prepared and analyzed along with all other samples.

Computational methods:
Duration of adsorption equilibration : 48h.
Sample No.:
#1
Type:
Kd
Value:
112 L/kg
pH:
7.1
Temp.:
21.5 °C
Matrix:
Clay
% Org. carbon:
1.66
Remarks on result:
other: CHIMEXANE HB C10-0
Sample No.:
#1
Type:
Koc
Value:
6 743 L/kg
pH:
7.1
Temp.:
21.5 °C
Matrix:
Clay
% Org. carbon:
1.66
Remarks on result:
other: CHIMEXANE HB C10-0
Sample No.:
#2
Type:
Kd
Value:
4 L/kg
pH:
6.23
Temp.:
21.5 °C
Matrix:
Sand
% Org. carbon:
0.92
Remarks on result:
other: CHIMEXANE HB C10-0
Sample No.:
#2
Type:
Koc
Value:
479 L/kg
pH:
6.23
Temp.:
21.5 °C
Matrix:
Sand
% Org. carbon:
0.92
Remarks on result:
other: CHIMEXANE HB C10-0
Sample No.:
#3
Type:
Kd
Value:
38 L/kg
pH:
7.01
Temp.:
21.5 °C
Matrix:
Loam
% Org. carbon:
1.19
Remarks on result:
other: CHIMEXANE HB C10-0
Sample No.:
#3
Type:
Koc
Value:
3 222 L/kg
pH:
7.01
Temp.:
21.5 °C
Matrix:
Loam
% Org. carbon:
1.19
Remarks on result:
other: CHIMEXANE HB C10-0
Sample No.:
#4
Type:
Kd
Value:
61 L/kg
pH:
6.41
Temp.:
21.5 °C
Matrix:
Activated sludge
% Org. carbon:
30.79
Remarks on result:
other: CHIMEXANE HB C10-0
Sample No.:
#4
Type:
Koc
Value:
199 L/kg
pH:
6.41
Temp.:
21.5 °C
Matrix:
Activated sludge
% Org. carbon:
30.79
Remarks on result:
other: CHIMEXANE HB C10-0
Sample No.:
#5
Type:
Kd
Value:
65 L/kg
pH:
6.5
Temp.:
21.5 °C
Matrix:
Activated sludge
% Org. carbon:
30.26
Remarks on result:
other: CHIMEXANE HB C10-0
Sample No.:
#5
Type:
Koc
Value:
233 L/kg
pH:
6.5
Temp.:
21.5 °C
Matrix:
Acyivated sludge
% Org. carbon:
30.26
Remarks on result:
other: CHIMEXANE HB C10-0
Sample No.:
#6
Type:
Kd
Value:
973 L/kg
pH:
7.1
Temp.:
21.5 °C
Matrix:
Clay
% Org. carbon:
1.66
Remarks on result:
other: CHIMEXANE HB C12-0
Sample No.:
#6
Type:
Koc
Value:
58 599 L/kg
pH:
7.1
Temp.:
21.5 °C
Matrix:
Clay
% Org. carbon:
1.66
Remarks on result:
other: CHIMEXANE HB C12-0
Sample No.:
#7
Type:
Kd
Value:
28 L/kg
pH:
6.23
Temp.:
21.5 °C
Matrix:
Sand
% Org. carbon:
0.92
Remarks on result:
other: CHIMEXANE HB C12-0
Sample No.:
#7
Type:
Koc
Value:
3 021 L/kg
pH:
6.23
Temp.:
21.5 °C
Matrix:
Sand
% Org. carbon:
0.92
Remarks on result:
other: CHIMEXANE HB C12-0
Sample No.:
#8
Type:
Kd
Value:
345 L/kg
pH:
7.01
Temp.:
21.5 °C
Matrix:
Loam
% Org. carbon:
1.19
Remarks on result:
other: CHIMEXANE HB C12-0
Sample No.:
#8
Type:
Koc
Value:
29 006 L/kg
pH:
7.01
Temp.:
21.5 °C
Matrix:
Loam
% Org. carbon:
1.19
Remarks on result:
other: CHIMEXANE HB C12-0
Sample No.:
#9
Type:
Kd
Value:
679 L/kg
pH:
6.41
Temp.:
21.5 °C
Matrix:
Avtivated sludge
% Org. carbon:
30.79
Remarks on result:
other: CHIMEXANE HB C12-0
Sample No.:
#9
Type:
Koc
Value:
2 204 L/kg
pH:
6.41
Temp.:
21.5 °C
Matrix:
Activated sludge
% Org. carbon:
30.79
Remarks on result:
other: CHIMEXANE HB C12-0
Sample No.:
#10
Type:
Kd
Value:
820 L/kg
pH:
6.5
Temp.:
21.5 °C
Matrix:
Activated sludge
% Org. carbon:
30.26
Remarks on result:
other: CHIMEXANE HB C12-0
Sample No.:
#10
Type:
Koc
Value:
2 942 L/kg
pH:
6.5
Temp.:
21.5 °C
Matrix:
Activated sludge
% Org. carbon:
30.26
Remarks on result:
other: CHIMEXANE HB C12-0
Sample No.:
#11
Type:
Kd
Value:
> 3 900 L/kg
pH:
7.1
Temp.:
21.5 °C
Matrix:
Clay
% Org. carbon:
1.66
Remarks on result:
other: CHIMEXANE HB C18-1
Sample No.:
#11
Type:
Koc
Value:
> 235 300 L/kg
pH:
7.1
Temp.:
21.5 °C
Matrix:
Clay
% Org. carbon:
1.66
Remarks on result:
other: CHIMEXANE HB C18-1
Sample No.:
#12
Type:
Kd
Value:
43 L/kg
pH:
6.23
Temp.:
21.5 °C
Matrix:
Sand
% Org. carbon:
0.92
Remarks on result:
other: CHIMEXANE HB C18-1
Sample No.:
#12
Type:
Koc
Value:
4 634 L/kg
pH:
6.23
Temp.:
21.5 °C
Matrix:
Sand
% Org. carbon:
0.92
Remarks on result:
other: CHIMEXANE HB C18-1
Sample No.:
#13
Type:
Kd
Value:
> 3 900 L/kg
pH:
7.01
Temp.:
21.5 °C
Matrix:
Loam
% Org. carbon:
1.19
Remarks on result:
other: CHIMEXANE HB C18-1
Sample No.:
#13
Type:
Koc
Value:
> 328 200 L/kg
pH:
7.01
Temp.:
21.5 °C
Matrix:
Loam
% Org. carbon:
1.19
Remarks on result:
other: CHIMEXANE HB C18-1
Sample No.:
#14
Type:
Kd
Value:
6 744 L/kg
pH:
6.41
Temp.:
21.5 °C
Matrix:
Activated sludge
% Org. carbon:
30.79
Remarks on result:
other: CHIMEXANE HB C18-1
Sample No.:
#14
Type:
Koc
Value:
21 903 L/kg
pH:
6.41
Temp.:
21.5 °C
Matrix:
Activated sludge
% Org. carbon:
30.79
Remarks on result:
other: CHIMEXANE HB C18-1
Sample No.:
#15
Type:
Kd
Value:
5 858 L/kg
pH:
6.5
Temp.:
21.5 °C
Matrix:
Activated sludge
% Org. carbon:
30.26
Remarks on result:
other: CHIMEXANE HB C18-1
Sample No.:
#15
Type:
Koc
Value:
21 010 L/kg
pH:
6.5
Temp.:
21.5 °C
Matrix:
Activated sludge
% Org. carbon:
30.26
Remarks on result:
other: CHIMEXANE HB C18-1
Details on results (HPLC method):
Not applicable.
Adsorption and desorption constants:
See table "Adsorption coefficient".
Recovery of test material:
The recoveries of the analytes from batch systems ranged from 31% to 100% for C10-0, from 11% to 71% for C12-0 and from 15% to 96% for C18-1. Low recoveries might be due to a low extraction efficiency of the applied generic extraction method. Because the recovery of the analytes from control batch systems containing 0.01 M CaCl2 solution without soil was within 100%±10% the test is regarded as valid. The control systems indicate stability of the analytes over the experimental period and during sample storage. They additionally proof negligible losses of analytes to the test tubes. Biotic transformation of the analytes during the test involving soil was ruled out since sterilized soils and sludges were used.
Concentration of test substance at end of adsorption equilibration period:
C10-0: Sorption of C10-0 to all soils and sludges increased with time. After 48h 34% to 82% of the initially applied C10-0 was sorbed.
C12-0: Sorption of C12-0 to all soils and sludges increased with time and was stronger than sorption of C12-0. After 48h 76% to 98% of the initially applied C12-0 was sorbed.
C18-1: Sorption of C18-1 to all soils and sludges was very strong, except for soil II. After 48h 30% to more than 98% of the initially applied C18-1 was sorbed.
Concentration of test substance at end of desorption equilibration period:
Not specified.
Transformation products:
not specified
Details on results (Batch equilibrium method):
Kinetics Test
Adsorption Kinetics

C10-0: Sorption of C10-0 to all soils and sludges increased with time. After 48h 34% to 82% of the initially applied C10-0 was sorbed. The corresponding distribution coefficients after 48h of adsorption are in increasing order 4 mL/g (soil II), 38 mL/g (soil III), 61 mL/g (soil IV (sludge)), 65 mL/g (soil V (sludge)) and 112 mL/g. For the three soils the distribution coefficient Kd is linearly correlated to the soil organic carbon content (%Corg), the cation exchange capacity (CEC) and the clay content. Still, the nature of the involved organic matter may affect the sorption extent, too, since the data of the sludges (soil IV and V) do not fall within the correlation of Kd-soil with Corg. In addition to the highest organic carbon content among the three tested soils, soil I has the highest clay content, too. Sorption may, hence, involve hydrophobic and cationic interaction with the soil constituents.
C12-0: Sorption of C12-0 to all soils and sludges increased with time and was stronger than sorption of C12-0. After 48h 76% to 98% of the initially applied C12-0 was sorbed. The corresponding distribution coefficients after 48h of adsorption are in increasing order 28 mL/g (soil II), 345 mL/g (soil III), 679 mL/g (soil IV (sludge)), 820 mL/g (soil V (sludge)) and 973 mL/g. The correlation of the Kd-values with selected soil properties is displayed in Figure 8. For the three soils the distribution coefficient Kd is linearly correlated to the soil organic carbon content (%Corg), the cation exchange capacity (CEC) and the clay content. Still, the nature of the involved organic matter may affect the sorption extent, too, since the data of the sludges (soil IV and V) do not fall within the correlation of Kd-soil with Corg. In addition to the highest organic carbon content among the three tested soils, soil I has the highest clay content, too. Sorption may, hence, involve hydrophobic and cationic interaction with the soil constituents.
C18-1: Sorption of C18-1 to all soils and sludges was very strong, except for soil II. After 48h 30% to more than 98% of the initially applied C18-1 was sorbed. The corresponding distribution coefficients after 48h of adsorption are in increasing order 43 mL/g (soil II), larger than 3’900 mL/g (soil I and soil III), 6’744 mL/g (soil IV (sludge)), 5’858 mL/g (soil V (sludge)). Because quantification of C18-1 in the supernatant of soil I and soil III was below quantification limits, an interpretation of the correlation is impossible. Sorption of C18-1 is in general stronger than for C10-0 and C12-0. However, in analogy to the related compounds C10-0 and C12-0 it is assumed, that the sorption extent of C18-1 in soils may increase with increasing Corg or clay content and with increasing cation exchange capacity.
Statistics:
Not specified.
Software Analyst.

Stability of the Test Item

The stability of the analytes was determined by LC/MS in control solutions containing 0.01 M CaCl2 and the test item at the test concentration. During 48 hours 100% ±10% of the initially applied test item (represented by the analytes C10-0, C12-0, C18-1) were recovered from glass and Teflon tubes. The three analytes were, hence, stable during the experiment, sample preparation and storage until analysis.

Ratio Finding Test

The overall adsorption extent of C10-0, C12-0 and C18-1 was large, increased with increasing chain length, and showed a dependency on the soil involved and the prevailing soil-to-solution ratio.

      C10-0: The sorbed percentage after 48 h of incubation ranged from about 15% to more than 99% of the applied amount. Sorption was strongest in soil I, where about 95% of applied were sorbed at a soil/solution ratio of 1/25. Between the three soils, sorption was lowest in soil II, where 15 to 94% of the applied amount was sorbed at soil solution ratios of 1/25 and 10/10. The sorption extent in both sludges was of comparable magnitude: about 72% to 94% of the applied amount were sorbed, depending on sludge and the sludge/solution ratio.

The estimated sorption coefficients Kd range therefore from about 4 mL/g to about 781 mL/g for the soils and from about 50 mL/g to 86 mL/g for the sludges.

      C12-0: The sorbed percentage after 48 h of incubation ranged from about 40% to more than 99% of the applied amount. Sorption was strongest in soil I, where the concentration in the aqueous phase was below quantifiable levels at all ratios. Hence, more than 99% of applied were sorbed. Between the three soils, sorption was lowest in soil II, where about 40% to 99% of the applied amount was sorbed at soil solution ratios of 1/25 and 10/10. The sorption extent in both sludges was of comparable magnitude: about 96% to 98% of the applied amount was sorbed.

The estimated sorption coefficients Kd range therefore from about 17 mL/g to about 300 mL/g for the soils and from about 200 mL/g to about 750 mL/g for the sludges.

      C18-1: The sorbed percentage after 48 h of incubation ranged from about 96% to more than 98% of the applied amount (Table 4). Sorption was strongest in soil I, where the concentration in the aqueous phase was close to below quantifiable levels at all ratios. Hence, about or more than 98% of applied was sorbed. Between the three soils, sorption was lowest in soil II, where about 97% or more than 98% of the applied amount was sorbed at soil solution ratios of 1/25 and 10/10.

The sorption extent in both sludges was of comparable magnitude: about 97% of the applied amount was sorbed.

The estimated sorption coefficients Kd range, therefore, from about 312 mL/g to more than 1’900 mL/g for the soils and from about 120 mL/g to about 1000 mL/g for the sludges.

Based on these results, the soil/solution ratios for the kinetics test were chosen for each substrate and analyte: Due to strong sorption a soil/solution ratio of 1/100 was selected for soil I, and the sludges soil IV and soil V for all analytes and for C18-1 for soil II and soil III, too. For C10-0 and C12-0 adsorption kinetics were determined at soil/solution ratio of 3:25 soil II and soil III.

Validity criteria fulfilled:
yes
Conclusions:
The adsorption/desorption behavior of Chimexane HB represented by analytes C10-0, C12-0 and C18-1 was investigated using four soil types covering a range of different soil properties: Speyer 6S (soil I, clay), Stolpe (soil II, sand), Mechtildshausen (soil III, loam), Sludge Füllinsdorf (soil IV, activated sludge) and sludge Sissach (soil V, activated sludge).

Koc results:
CHIMEXANE HB C10-0 : from 199 (soil IV) to 6743 (soil I) L/Kg
CHIMEXANE HB C12-0 : from 2204 (soil IV) to 58599 (soil I) L/Kg
CHIMEXANE HB C18-1 : from 4634 (soil II) to >328200 (soil III) L/Kg
Executive summary:

The adsorption/desorption behavior of Chimexane HB represented by analytes C10-0, C12-0 and C18-1 was investigated using four soil types covering a range of different soil properties: Speyer 6S (soil I, clay), Stolpe (soil II, sand), Mechtildshausen (soil III, loam), Sludge Füllinsdorf (soil IV, activated sludge) and sludge Sissach (soil V, activated sludge).

Sorption of C10-0, C12-0 and C18-1 to the investigated soils and sludges exhibited a dependency on the specific analyte, the soil/sludge involved and on the prevailing soil-to-solution ratio. In general sorption extent increased in the order of C10-0 < C12-0 < C18-0 corresponding to the increasing hydrophobicity. Sorption extent was lowest in the sand (soil II), followed by the loam (soil III), and the sludges (soil IV and soil V) and highest in the cay (soil I). Among the three soils, soil I (clay) has the highest organic carbon content, too, which is, however, well below the organic carbon content of the sludges (soil IV and soil V). Sorption of the three analytes may, hence, involve hydrophobic and cationic interaction with the soil constituents.

As expected, the sorbed fraction of analyte increased the more soil was involved in the batch systems. Whether an apparent equilibrium distribution was reached within 48h cannot be decided: the sorbed fraction slightly increased for most samples from the 24h sampling to the 48h sampling interval. The adsorption coefficients were calculated after 48h of adsorption:

Analyte

Parameter

Unit

Soil I

Soil II

Soil III

Soil IV

Soil V

C10-0

 

Kd

[mL/g]

112

4

38

61

65

Koc

[mL/g]

6743

479

3222

199

233

C12-0

 

Kd

[mL/g]

973

28

345

679

820

Koc

[mL/g]

58599

3021

29006

2204

2942

C18-1

 

Kd

[mL/g]

>3900

43

>3900

6744

5858

Koc

[mL/g]

>235300

4634

>328200

21903

21010

Description of key information

The adsorption behavior of the test item, Chimexane HB, was determined in three soils and two sludges using the batch equilibrium method according to OECD Guideline No. 106 with GLP statement.

Three single components of Chimexane HB (C10-0, C12-0, C18-1) were chosen for analysis according to their abundance in the mixture and varying chain length.

KOCs of C10 -0 range from 199 to 6743 ml/g.

Two key values are selected ( the lower and the upper value) for risk assessment.

As supporting information, the adsorption coefficient of the test item has alos been predicted using the equations form Sabljic and Güsten (1995) for non hydrophobic substances.

Key value for chemical safety assessment

Koc at 20 °C:
199

Additional information

Two headchapters are created in order to take into account both extrem values for risk assessment.

Two assessment entities are created. Each represents the whole substance but are related to different Koc key values.