2-(2-(4-methyl-3-cyclohexen-1-yl)propyl)cyclopentanone

Adsorption / desorption

Link to relevant study record(s)

Reference

Endpoint:

adsorption / desorption, other

Type of information:

experimental study

Adequacy of study:

key study

Study period:

03 November 2008 through 31 March 2009

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Remarks:

No desorption phase nor mass balance performed.

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of method:

batch equilibrium method

Media:

soil

Specific details on test material used for the study:

NECTARYL :
- Batch No. : 9000751030
- Purity : 96 %
- Expiry Date : 14 May 2009

Radiolabelling:

no

Test temperature:

20 +/- 2 °C

Analytical monitoring:

yes

Details on sampling:

The study was performed with three soils of differing physico-chemical properties : Speyer 2.2 (Matrix #1), Speyer 2.3 (Matrix # 2) and Speyer 6S (Matrix #3).

Determination of the choice of Soil : Solution ratio :
An initial experiment was performed to determine the soil to solution ratio that should be applied for the adsorption kinetics and adsorption isotherm experiments.
The test soils were agitated on a roler mixer for 24 hour contact time at a soil : solution ratio of 1 : 10, 1 : 50 and 1 : 100.

Determination of Equilibrium Time (Adosprtion Kinetics) :
A soil : solution ratio of 1 : 50 was chosen. Test soils were agitated on a roler-mixer for four days at 20 +/- 2 °C. Following equilibration, the samples were spiked with the test item at a concentration of 1.0 mg/L. Samples were taken and prepared following a contact time of 3, 6, 24 and 48 hours.

Determination of Adsorption Isotherms :
The adsorption kinetics phase of the study indicatedf that a plateau had been attained by 24 hours. The adsorption isotherm part of the study was, therefore, conducted with a contact time of 24 hours. Adsorption isotherms for the three test soils were developed using initial concentrations at 0.20, 1.00, 4.99, 9.99, 20.0 mg/L, in duplicate.

Matrix no.:

#1

Matrix type:

loamy sand

% Clay:

6.4

% Silt:

12.7

% Sand:

80.9

% Org. carbon:

2.16

pH:

5.4

CEC:

10 meq/100 g soil d.w.

Matrix no.:

#2

Matrix type:

loamy sand

% Clay:

9.4

% Silt:

31.9

% Sand:

58.7

% Org. carbon:

0.98

pH:

6.4

CEC:

8 meq/100 g soil d.w.

Matrix no.:

#3

Matrix type:

clay loam

% Clay:

42.1

% Silt:

37

% Sand:

20.9

% Org. carbon:

1.75

pH:

7.2

CEC:

22 meq/100 g soil d.w.

Details on matrix:

All soils sampled from the 0 - 20 cm horizon.

Sample No.:

#1

Phase system:

soil-water

Type:

other: Freundlich-Partition Coefficient (Kf), normalised to Organic Carbon

Remarks:

Kf, OC

Value:

4 930 L/kg

Temp.:

20 °C

Matrix:

Speyer 2.2 (Loamy Sand - Matrix #1)

% Org. carbon:

2.16

Sample No.:

#2

Phase system:

soil-water

Type:

other: Freundlich-Partition Coefficient (Kf), normalised to Organic Carbon

Remarks:

Kf, OC

Value:

5 530 L/kg

Temp.:

20 °C

Matrix:

Speyer 2.3 (Loamy Sand - Matrix #2)

% Org. carbon:

0.98

Sample No.:

#3

Phase system:

soil-water

Type:

other: Freundlich-Partition Coefficient (Kf), normalised to Organic Carbon

Remarks:

Kf, OC

Value:

5 469 L/kg

Temp.:

20 °C

Matrix:

Speyer 6S (Clayey Loam - Matrix #3)

% Org. carbon:

1.75

Key result

Phase system:

soil-water

Type:

other: Mean Freundlich-Partition Coefficient (Kf), normalised to Organic Carbon

Remarks:

Mean Kf, OC

Value:

5 310 L/kg

Temp.:

20 °C

Matrix:

Mean Kf, OC for the three soils studies, mean Freundlich-Partition Coefficient (Kf), normalised to Organic Carbon

% Org. carbon:

>= 0.98 - <= 2.16

Adsorption and desorption constants:

Freundlich Adsorption Isotherm derived Partition Coefficients :

Speyer 2.2 (Matrix #1) - Kf = 106.5 L/kg; Kf, OC = 4930 L/kg; Kf, OM = 2860 L/kg

Speyer 2.3 (Matrix #2) - Kf = 54.2 L/kg; Kf, OC = 5530 L/kg; Kf, OM = 3208 L/kg

Speyer 6S (Matrix #3) - Kf = 95.7 L/kg; Kf, OC = 5469 L/kg; Kf, OM = 3172 L/kg

Recovery of test material:

A mass balance approach was not performed.

Details on results (Batch equilibrium method):

Adsorption of Nectaryl on soil could be described by a Freundlich adsorption isotherm. The Freundlich-Partition Coefficient (Kf), normalised to Organic Carbon (Kf, OC) values determined for the three different soils :

- Speyer 2.2 (Matrix #1) : 4930 L/kg

- Speyer 2.3 (Matrix #2) : 5530 L/kg

- Speyer 6S (Matrix #3) : 5469 L/kg

The test item, Nectaryl, can be considered as IMMOBILE in soil.

Validity criteria fulfilled:

yes

Conclusions:

Adsorption of Nectaryl on soil could be described by a Freundlich adsorption isotherm. The Freundlich-Partition Coefficient (Kf), normalised to Organic Carbon (Kf, OC) values determined for the three different soils :

- Speyer 2.2 (Matrix #1) : 4930 L/kg

- Speyer 2.3 (Matrix #2) : 5530 L/kg

- Speyer 6S (Matrix #3) : 5469 L/kg

The test item, Nectaryl, can be considered as IMMOBILE in soil.

Description of key information

Adsorption of Nectaryl on soil could be described by a Freundlich adsorption isotherm.  The Freundlich-Partition Coefficient (Kf), normalised to Organic Carbon (Kf, OC) values determined for the three different soils :

- Speyer 2.2 (Matrix #1) : 4930 L/kg

- Speyer 2.3 (Matrix #2) : 5530 L/kg

- Speyer 6S (Matrix #3) : 5469 L/kg

The average of Koc for the three soils studied was 5310 L/kg (LogKoc = 3.725).

The test item, Nectaryl, can be considered as IMMOBILE in soil.

Key value for chemical safety assessment

Koc at 20 °C:

5 310