Oleic acid, compound with (Z)-N-octadec-9-enylpropane-1,3-diamine

Adsorption / desorption

Link to relevant study record(s)

Reference

Endpoint:

adsorption / desorption: screening

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2011-12-12 to 2012-04-20

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: A GLP study performed according to OECD 106 fulfilling all quality criteria.

Qualifier:

according to guideline

Guideline:

OECD Guideline 106 (Adsorption - Desorption Using a Batch Equilibrium Method)

Deviations:

yes

Remarks:

Three soils tested instead of five

Principles of method if other than guideline:

In the test three soils instead of one was used. The partitioning to soil is not based on a Freundlich isotherm but evaluated based on only one test concentration. These deviations are based on results of earlier adsorption desorption tests with cationic surfactants. The amines in the test substance will to a large extent be protonated under ambient conditions and will therefore interact with the negative surface of mineral particles or with negative charges of humic substances. The ionic interactions play a more important role than hydrophobic partitioning with organic matter. The log Koc is therefore considered as a poor predictor of the partitioning behaviour of cationic surfactants in the environment. These earlier results showed that using three soils with at least one loamy sand and a clay soil, can give as much information as using the full number of soils. These earlier tests also revealed that only rarely linear adsorption isotherms were obtained for cationic surfactants and that extrapolation to lower concentrations based on these non-linear isotherms leads to unrealistic results (e.g. RAR primary fatty amines Oct. 2008). According to the Danish EPA (2004) a more reliable method of extrapolation to lower concentrations, is to use the data originating from the lowest measured concentration and to assume that the coefficient remains constant at lower concentrations. The test as described in this report is therefore performed using only one concentration which is as low as reasonably possible in relation to the detection limit.

GLP compliance:

yes (incl. QA statement)

Type of method:

batch equilibrium method

Media:

soil

Radiolabelling:

no

Test temperature:

20°C

Analytical monitoring:

yes

Details on matrix:

8.2.1. Speyer 2.2 soil
Name Speyer standard soil type 2.2 (Sp2.2 1109)
Location "Grosser Striet", Nr.585, Hanhofen, Rheinland-Pfalz, Germany
Sampling date 2009.03.12
Received from Landwirtschaftliche Untersuchungs- und Forschungsanstalt Speyer, Obere Langgasse 40, 67346 Speyer, Germany
Sieved/air dried on March 23, 2009
Storage Received on March 30 from Speyer and further air dried on April 16. Stored at ambient temperature.
Texture (USDA) Loamy sand
pH (0.01 M CaCl2) 5.4 ± 0.1
Organic carbon (%) 2.16 ± 0.40
Particle size distribution % clay (< 2 µm) 6.4 ± 0.9
(USDA) % silt (2-50 µm) 12.2 ± 0.6
% sand (50-2000 µm) 81.4 ± 1.2
CEC (meq/100g) 10 ± 1
Water holding capacity (%) 48.2 ± 5.0

8.2.2. Eurosoil no 4
Name Eurosoil 4. Certified Reference Material IRMM-443-4. No 0034
Location Data can be obtained from IRMM
Sampling date Data can be obtained from IRMM
Received from EC-JRC-IRMM, Unit for Reference Materials, Retieseweg 111, 2440 Geel, Belgium
Sieved/air dried on Data can be obtained from IRMM
Storage Received on March 17, 2009 from LGC Standards . Stored at ambient temperature.
Texture (USDA) Silt
pH (0.01 M CaCl2) 6.8 ± 0.6
Organic carbon (%) 1.31
Particle size distribution % clay (< 2 µm) 20.3
(USDA) % silt (2-50 µm) 75.7
% sand (50-2000 µm) 4.1
CEC (meq/100g) 17.3
Water holding capacity (%) Data can be obtained from IRMM

8.2.3. Speyer 6S soil
Name Speyer standard soil type 6S (Speyer 6S 0809)
Location "In der unteren Hohnert", Nr.3412, Siebeldingen, Rheinland-Pfalz, Germany
Sampling date 2009-02-18
Received from Landwirtschaftliche Untersuchungs- und Forschungsanstalt Speyer, Obere Langgasse 40, 67346 Speyer, Germany
Sieved/air dried on February 26, 2009
Storage Received on March 30 from Speyer and further air dried on April 16. Stored at ambient temperature.
Texture (USDA) Clay
pH (0.01 M CaCl2) 7.2 ± 0.1
Organic carbon (%) 1.75 ± 0.11
Particle size distribution % clay (< 2 µm) 42.1 ± 1.8
(USDA) % silt (2-50 µm) 36.0 ± 2.3
% sand (50-2000 µm) 21.9 ± 1.6
CEC (meq/100g) 22 ± 6
Water holding capacity (%) 40.7 ± 5.0

Details on test conditions:

The test substance was expected to strongly adsorb on soil material. Adsorption / desorption tests on structurally similar surfactants have shown that a 1 : 100 soil solution ratio is appropriate and this ratio has been chosen for the final test.

A 0.01 M CaCl2 solution was prepared by dissolving 1.471 g of calcium chloride dihydrate in water to 1 L (0.010 M).
A spike solution was made by weighing about 25 mg of the test substance in a 100 mL measuring flask and dissolving in methanol (active content of the test substance is 99.3% according to the Certificate of Analysis).
About 250 mg soil (Speyer 2.2 and 6S) and 24.9 mL of 0.01 M CaCl2 solution was equilibrated in a capped glass centrifugation tube on a shaker at 20 ± 1°C during one night in the dark prior to spiking. The pH was measured during the tests, see Table 8. The test, conducted in triplicate for each soil, was started by adding 100 μL of spike solution to the pre-equilibrated soil slurries, giving a final total concentration of approximately 1.0 mg/L. The three measured components cover approximately 88 % of the total amount of the reaction product.
Blanks were also prepared in the same way but omitting the spike solution (and pre-equilibrating in 25.0 mL 0.01 M CaCl2 solution).
The samples were placed on a shaker at 20 ± 1°C in the dark. At the adsorption sampling times 3, 6 and 24 hours, the centrifuge tubes were removed from the shaker and were centrifuged for 5 minutes at 3000 g. A 0.5 mL aliquot of the supernatant was taken from each sample (including blanks) and were transferred to HPLC vials containing 0.5 mL of leaching solution (magnesium chloride dissolved in methanol/2-propanol, see LCMS method) with internal standard and analysed by LCMS according to Analytical Center method 11 AM 0021-01,


8.8. Preliminary Study. Adsorption on test vessel surfaces and Stability of Test Substance
For the 24 hrs samples, including blanks, the adsorption of test substance to glassware was determined. After the sampling of supernatant, the tube was shaken by hand and the total content was removed. The tube and cap were rinsed with 3 x 10 mL of water, which was discarded. 25 mL of leaching solution was added to the tube, which was placed in a ultrasonication bath for 10 minutes and then on the shaker for 30 minutes. 0.5 mL of the solution was transferred to an HPLC vial containing 0.5 mL of leaching solution with internal standard for LCMS.
Control sample tubes, in triplicate, containing 24.9 mL 0.01 M CaCl2 solution but no soil were equilibrated during one night in the same way as the samples. 100 μL spike solution was added and control samples were run parallel to the soil samples for 24 hours. The water dissolved and glass adsorbed test substance were analysed as above.

8.9. Adsorption and Desorption Kinetics
This test was performed with the same experimental conditions as described above except 7 times higher spike solution concentration. The adsorption kinetics part was run for 24 hours. After this time the supernatant was removed and replaced by 25.0 mL 0.01 M CaCl2 (aq) solution. The desorption kinetics part was run for 48 hours.

Computational methods:

All calculations are based on formulas given in OECD Guideline 106. The calculations was based on the mean value of the three replicates a, b and c used in the test.
All calculations were performed with non-rounded values.

Type:

Kd

Value:

32 558

Temp.:

20 °C

% Org. carbon:

2.16

Remarks on result:

other: Loamy sand

Type:

Kd

Value:

37 961

Temp.:

20 °C

% Org. carbon:

1.31

Remarks on result:

other: Silt

Type:

Kd

Value:

19 686

Temp.:

20 °C

% Org. carbon:

1.75

Remarks on result:

other: Clay

Adsorption and desorption constants:

Soil type Kd Koc Kdes
(10^4 cm3/g) (10^6 cm3/g) (10^4 cm3/g)

Speyer 2.2 3.3 1.4 4.2
Speyer 6S 2.0 1.1 10
Eurosoil 4 3.8 2.9 5.9

Recovery of test material:

Table: Total recovery and adsorption of N-[(9Z)-octadec-9-en-1-yl]propane-1,3-diaminum di[(9Z)-octadec-9-enoate] to container wall from control samples after 24 hours.
Replicate Added Amount Amount desorbed Recovery (total) Adsorption to glass container
test substance found in water from glass
(µg) (µg) (µg) (%) (%)
A 25.14 3.09 16.62 78.6 66.1
B 25.14 4.16 15.32 77.6 60.9
C 25.14 3.54 15.73 76.8 62.6

Concentration of test substance at end of adsorption equilibration period:

Speyer 2.2: 13 - 33.7 ug/L
Speyer S6: 22.6- 53.5 ug/L
Eurosoil 4: 11 - 28 ug/L

Concentration of test substance at end of desorption equilibration period:

Speyer 2.2: 15.1 - 16.9 ug/L
Speyer S6: 4.6- 10.8 ug/L
Eurosoil 4: 9.6 - 17.8 ug/L

Transformation products:

no

Details on results (Batch equilibrium method):

see remarks on results

Statistics:

No specific statistics was applied

Table:  Detailed results for stability and adsorption to container wall investigations on control samples after 24 hours in the preliminary study

Analyte	Replicate	Added test substance	Amount in water	Amount desorbed from glass	Recovery (total)	Adsorption to glass container
		(µg)	(µg)	(µg)	(%)	(%)
C16’	A	1.71	0.44	0.91	79.1	53.4
	B	1.71	0.65	0.71	79.4	41.6
	C	1.71	0.64	0.74	80.6	43.2
C18’’	A	2.26	0.36	1.33	74.5	58.8
	B	2.26	0.52	1.22	76.7	54.0
	C	2.26	0.44	1.21	73.1	53.5
C18’	A	21.12	2.30	14.37	79.0	68.1
	B	21.12	3.00	13.39	77.6	63.4
	C	21.12	2.46	13.78	76.9	65.2

 

Table Detailed results from the adsorption kinetics investigation

Analyte	Replicate	Speyer2.2			Speyer6S
		Adsorption at time t (%)			Adsorption at time t (%)
		3h	6h	24h	3h	6h	24h
C16’	A	98.2	98.7	99.2	99.5	99.6	99.6
	B	98.4	98.8	99.2	99.5	99.6	99.6
	C	98.0	98.8	99.1	99.5	99.6	99.6
C18’’	A	97.6	98.1	98.4	99.0	98.9	99.1
	B	97.7	98.1	98.4	98.9	99.0	99.1
	C	97.8	98.1	98.3	99.0	99.0	99.0
C18’	A	97.2	98.3	98.4	99.4	99.4	99.5
	B	97.4	98.0	98.4	99.3	99.3	99.4
	C	97.9	97.9	97.8	99.4	99.4	99.4

 

Table  Results for adsorption/desorption parameters for individual components

Soil type	Component	Kd (10^4cm^3/g)	Koc (10^6cm^3/g)	Kdes (10^4cm^3/g)
Speyer2.2	C16’	1.3	0.57	2.0
	C18’’	2.3	1.0	3.7
	C18’	4.1	1.7	4.7
Speyer6S	C16’	1.4	0.76	6.5
	C18’’	1.9	1.0	11
	C18’	2.0	1.1	11
Eurosoil 4	C16’	2.5	1.9	3.2
	C18’’	3.4	2.6	5.1
	C18’	4.1	3.1	6.5

 

Table 1. Recovery measured on control samples during the adsorption/desorption study

Replicate	C16’ (%)	C18’’ (%)	C18’ (%)	Total recovery (%)
A	85	87	87	87
B	82	81	82	82
C	82	82	83	83

 

Validity criteria fulfilled:

yes

Conclusions:

A reliable, valid and adequate screening study. Test is performed according to a refined OECD guideline 106 under GLP conditions at one concentration and with 3 soils. These 3 soils used cover a wide range of soil characteristcs and therefore can be considered as sufficient.

Executive summary:

This study reports adsorption and desorption parameters for N-[(9Z)-octadec-9-en-1-yl]propane-1,3-diaminum di[(9Z)-octadec-9-enoate], on soil measured according to a refined OECD Guideline no 106; Adsorption – Desorption using the Batch Equilibrium Method, adopted 21 January 2000. K_d, K_oc and K_des values have been calculated.

The preliminary test to determine the equilibrium time showed that equilibrium is reached within 24 hours for both the 2.2 soil and the 6S soil. There are only minor changes between the 3 and 24 hours samples. Based on these results, an equilibrium time of 24 hours was applied for the definitive test. The measured equilibrium concentrations in the water phase had an average of 6.8 and 1.6 µg/L respectively and it was decided to increase the starting concentration to about 7 mg/L.

The final sorption test was performed for 24 hours followed by a 48 hours desorption test. The observed K_dvalues in the preliminary and final sorption test agree well. K_d for Speyer 2.2 is 1.5*10⁴in the preliminary test and 3.3*10⁴in the final sorption test, a difference of a factor of approximately 2.3. The K_dvfor Speyer 6S is 6.5*10⁴and 2.0*10⁴for the preliminary and final sorption test, respectively.

The recovery for the control sample in the final sorption test was 84%. The recovery of the individual components varies between 81% to 87%. T

he results are calculated as a sum for all three components (C16’, C18’’ and C18’) individual contribution to the total amount test substance adsorbed and desorbed. When these results achieved with different soils are compared it can be noticed that the K_descorrelates with CEC, pH and clay content, while the organic carbon content of the soils not seems to have a major impact on the desorption of the substance to the soils. Adsorption measured as Kd do not seem to correlate to any individual parameter, this might indicate that it is not the hydrofobicity that is the main driver for adsorption to different soil particles and to glassware.

Table . Comparison between the results and soils

Soil	Clay (%)	Silt (%)	Sand (%)	CEC (meq/100g)	pH	Org C (%)	Caq (µg/l)	Kd (10^4cm^3/g)	Koc (10^6cm^3/g)	Kdes (10^4cm^3/g)
Speyer2.2	6.4	12.2	81.4	10	5.4	2.16	24.1	3.3	1.4	4.2
Eurosoil 4	20.3	75.7	4.1	17.3	6.8	1.31	38.9	3.8	2.9	5.9
Speyer6S	42.1	36.0	21.9	22	7.2	1.75	21.0	2.0	1.1	10

 

Description of key information

N-(Oleyl alkyl)- 1,3-propanediamine mono oleates is the salt (1:1 molar ratio) of Oleyldiamine (CAS no 7173-62-8) and oleic acid (CAS no. 112-80-1) and will dissociate partly under ambient conditions (pKa = 7.0) into the both constituents.

The amines in the test substance have formed an ionpair with oleic acid and due to that initially only for a certain fraction of the test substance ionic interaction is expected to occur very similar to

N-(Oleyl alkyl)- 1,3-propanediamine di-oleates (= N-[(9Z)-octadec-9-en-1-yl]propane-1,3-diaminum di[(9Z)-octadec-9-enoate]) which is the salt (1:2 molar ratio) of Oleyldiamine (CAS no 7173 -62 -8) and oleic acid (CAS no. 112 -80 -1). The results of the sorption test with N-(Oleyl alkyl)- 1,3-propanediamine di-oleates is as a worst-case used to for read across. Sorption of N-(Oleyl alkyl)- 1,3-propanediamine di-oleates is anticipated to be slightly stonger based on the higher calculated log Kow.

When considering the results from N-(Oleyl alkyl)- 1,3-propanediamine di-oleates there is no relationship between the observed Kd values and soil properties like Koc, CEC, pH  and clay content. In general the log Koc is considered to be a poor predictor of the partitioning behaviour of cationic surfactants in the environment but this substance is an ion-pair (salt). The sorption test results are therefore not expressed in Koc but in their Kd  values. The mean Kd value for three soils of 30068 L/kg will be used as a realistic worst-case to derive the distribution constants for . This Kd value of 30068 L/kg corresponds with a Koc of 601360 L/kg. This latter Koc may be used to derive other Kd values for risk assessment purposes.

Because there is no principal difference between soil and sediments considering the sorption properties (EU RAR primary alkyl amines, 2008) and because for this substance the degree of sorption is not related to the organic carbon content, the value for soil will also be used for sediment, suspended particles and STP sludge.  

In the table below the distribution constants used in this assessment are summarized:

Kpsoil = 30068 L/kg;       Ksoil-water = 45102 m3/m3

Kpsusp = 60136 L/kg;  Ksusp-water = 15035 m3/m3

Kpsed = 30068 L/kg;       Ksed-water = 15035 m3/m3

With a Kpsusp of 60136 L/kg and a concentration of 15 mg/L suspended matter in surface waters, the adsorbed fraction is calculated as 47.5%.

Key value for chemical safety assessment

Koc at 20 °C:

601 360

Other adsorption coefficients

Type:

log Kp (solids-water in soil)

Value in L/kg:

4.478

at the temperature of:

20 °C

Other adsorption coefficients

Type:

log Kp (solids-water in sediment)

Value in L/kg:

4.478

at the temperature of:

20 °C

Other adsorption coefficients

Type:

log Kp (solids-water in suspended matter)

Value in L/kg:

4.78

at the temperature of:

20 °C

Additional information

N-(Oleyl alkyl)- 1,3-propanediamine mono oleates is the salt (1:1 molar ratio) of Oleyldiamine (CAS no 7173-62-8) and oleic acid (CAS no. 112-80-1) and will dissociate partly under ambient conditions (pKa = 7.0) into the both constituents.

The amines in the test substance have formed an ionpair with oleic acid and due to that initially only for a certain fraction of the test substance ionic interaction is expected to occur very similar to

N-(Oleyl alkyl)- 1,3-propanediamine di-oleates (= N-[(9Z)-octadec-9-en-1-yl]propane-1,3-diaminum di[(9Z)-octadec-9-enoate]) which is the salt (1:2 molar ratio) of Oleyldiamine (CAS no 7173 -62 -8) and oleic acid (CAS no. 112 -80 -1). The results of the sorption test with N-(Oleyl alkyl)- 1,3-propanediamine di-oleates is as a worst-case used to for read across. Sorption of N-(Oleyl alkyl)- 1,3-propanediamine di-oleates is anticipated to be slightly stonger based on the higher calculated log Kow.

The available study reports adsorption and desorption parameters for N-[(9Z)-octadec-9-en-1-yl]propane-1,3-diaminum di[(9Z)-octadec-9-enoate], on soil measured according to a refined OECD Guideline no 106; Adsorption – Desorption using the Batch Equilibrium Method, adopted 21 January 2000. K_d, K_oc and K_des values have been calculated.

The preliminary test to determine the equilibrium time showed that equilibrium is reached within 24 hours for both the Speyer 2.2 soil and the Speyer 6S soil. There are only minor changes between the 3 and 24 hours samples. Based on these results, an equilibrium time of 24 hours was applied for the definitive test. The measured equilibrium concentrations in the water phase had an average of 6.8 and 1.6 µg/L respectively in the preliminary test and it was decided to increase the starting concentration to about 7 mg/L in the final test.

The final sorption test was performed for 24 hours followed by a 48 hours desorption test. The observed K_d values in the preliminary and final sorption test agree well. K_d for Speyer 2.2 is 1.5*10⁴ in the preliminary test and 3.3*10⁴ in the final sorption test, a difference of a factor of approximately 2.3. The K_d for Speyer 6S is 6.5*10⁴ and 2.0*10⁴ for the preliminary and final sorption test, respectively.

The recovery for the control sample in the final sorption test was 84%. The recovery of the individual components varies between 81% to 87%.

The results are calculated as a sum for all three components (C16’, C18’’ and C18’) individual contribution to the total amount test substance adsorbed and desorbed. When these results

achieved with different soils are compared (Table 7), it can be noticed that the K_des correlates with CEC, pH and clay content, while the organic carbon content of the soils not seems to have a major impact on the desorption of the substance to the soils. Adsorption measured as Kd do not seem to correlate to any individual parameter, this might indicate that it is the hydrofobicity that is the main driver for adsorption to different soil particles and to glassware.

Table 1. Comparison between the results and soils

Soil	Clay (%)	Silt (%)	Sand (%)	CEC (meq/100g)	pH	Org C (%)	Caq (µg/l)	Kd (10^4cm^3/g)	Kdes (10^4cm^3/g)
Speyer 2.2	6.4	12.2	81.4	10	5.4	2.16	24.1	3.3	4.2
Eurosoil 4	20.3	75.7	4.1	17.3	6.8	1.31	38.9	3.8	5.9
Speyer 6S	42.1	36.0	21.9	22	7.2	1.75	21.0	2.0	10