6'-(dibutylamino)-3'-methyl-2'-(phenylamino)spiro[isobenzofuran-1(3H),9-(9H)-xanthen]-3-one

Adsorption / desorption

Link to relevant study record(s)

Reference

Endpoint:

adsorption / desorption: screening

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Qualifier:

according to guideline

Guideline:

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

GLP compliance:

yes

Type of method:

batch equilibrium method

Media:

soil

Test temperature:

25 °C

Analytical monitoring:

not specified

Matrix no.:

#1

Matrix type:

sandy loam

Matrix no.:

#2

Matrix type:

sandy clay loam

Matrix no.:

#3

Matrix type:

clay

Sample No.:

#1

Duration:

2 h

Sample No.:

#2

Duration:

2 h

Sample No.:

#3

Duration:

2 h

Sample no.:

#1

Duration:

2 h

Sample no.:

#2

Duration:

2 h

Sample no.:

#3

Duration:

2 h

Key result

Sample No.:

#1

Type:

Koc

Value:

126 dimensionless

% Org. carbon:

1.32

Key result

Sample No.:

#2

Type:

Koc

Value:

2 053 dimensionless

% Org. carbon:

3.73

Key result

Sample No.:

#3

Type:

Koc

Value:

252 dimensionless

% Org. carbon:

1.65

Duration:

2 h

% Adsorption:

96.2

Duration:

2 h

% Desorption:

>= 1.5 - <= 3.1

Transformation products:

no

Adsorption kinetics:

96.2 % was absorbed within 2 hours

Adsorption isotherms:

126 to 2053 (Freundlich adsorption constants)

Adsorptions coefficient:

126 to 2053 (Freundlich adsorption constants).

Mass balance:

Recovery 95 - 107 %

Validity criteria fulfilled:

not specified

Conclusions:

The test item was strongly adsorbed to all three soils tested. Based on the results obtained, the test item can be regarded as having a low potential for motility in soil.

Executive summary:

The adsorption/desorption behaviour of the test substance was determined in a batch equilibrium method equivalent to OECD guideline 106 (Huntingdon, ECHA RSS, 2017). Somersham sandy loan, Sandiacre clay loam and Alconbury clay were tested. The following results were obtained:

 

Soil type	Organic	Ka	Koc	Kom	1/n	Kd
Sandy loam	1.32	126	9563	5560	0.72	474
Clay loam	3.73	2053	55023	31990	1.04	342
Clay	1.65	252	15255	8869	0.83	15

Ka = Freundlich adsorption coef

Kom = Coefficient of adsorption per unit organic matter

1/n = Slope of the Freundlich adsorption isotherm

Kd = Freundlich desorption coefficient

 

Between 96.2 % of the test substance were adsorbed after 2 hours. Only 1.5 to 3.1 % had been desorbed after 2 hours. The test item was strongly adsorbed to all three soils tested. Based on the results obtained, the test item can be regarded as having a low potential for motility in soil.

Description of key information

The test item can be classified as having a low potential for motility in soil (Huntingdon, ECHA RSS, 2017).

Key value for chemical safety assessment

Koc at 20 °C:

2 053

Additional information

Key Study

In an adsorption/desorption study equivalent to OECD guideline 106 (Huntingdon, ECHA RSS, 2017), the motility of the test substance was determined in three different types of soil (Somersham sandy loan, Sandiacre clay loam and Alconbury clay). 96.2 % of the test substance was absorbed within 2 hours. An adsorption coefficient of 126 to 2053 and a mass balance of 95 - 107 % were determined.

Based on these results the test substance can be regarded as having a low potential for motility in soil.