1,3,5-Triazin-2-amine, 4-methoxy-6-(trifluoromethyl)-

Adsorption / desorption

Administrative data

Endpoint:

adsorption / desorption: screening

Type of information:

experimental study

Adequacy of study:

other information

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

secondary literature

Data source

Reference

Reference 1

Reference Type:

study report

Title:

Unnamed

Year:

2015

Reference 2

Reference Type:

other: Draft Renewal Assessment Report under Regulation (EC) 1107/2009

Title:

Draft Renewal Assessment Report under Regulation (EC) 1107/2009 - Tritosulfuron

Year:

2018

Bibliographic source:

Draft Renewal Assessment Report under Regulation (EC) 1107/2009

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

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

GLP compliance:

yes

Type of method:

batch equilibrium method

Test material

Test material information

Constituent 1

Reference substance name:

4-methoxy-6-(trifluoromethyl)-1,3,5-triazin-2-amine

EC Number:

610-962-9

Cas Number:

5311-05-7

Molecular formula:

C5H5F3N4O

IUPAC Name:

4-methoxy-6-(trifluoromethyl)-1,3,5-triazin-2-amine

Study design

Batch equilibrium or other method

Matrix properties

Matrix properties 1

Matrix no.:

#1

Matrix type:

sandy clay loam

Matrix properties 2

Matrix no.:

#2

Matrix type:

loamy sand

Matrix properties 3

Matrix no.:

#3

Matrix type:

sandy loam

Matrix properties 4

Matrix no.:

#4

Matrix type:

sandy loam

Matrix properties 5

Matrix no.:

#5

Matrix type:

silt loam

Results and discussion

Results: Batch equilibrium or other method

Adsorption and desorption constants:

Calculated p-values above 0.3 were obtained for the soils La Gironda, Li 10 and Nierswalde Wildacker. For the soils Lufa 2.3 and Lufa 5M, the p-value was below that value. Besides the p-values being an indicator for significant adsorption, the correlation coefficient of the Freundlich isotherm graph was considered as a measure of reliability of the results. The excellent correlation coefficients of 0.992 and 0.999 for the fit for the data of the two soils were well in the range of the other soils. This indicates that the experimental design as well as the analytical methodology (with low random error and measuring uncertainty) was suitable for the accurate determination of adsorption coefficients and properties of M635H004 in all soils, including soils Lufa 2.3 and Lufa 5M.

Applicant's summary and conclusion

Validity criteria fulfilled:

not specified

Conclusions:

The mass balance of the test item was determined from the results of radioactivity measurements of the aqueous phase and soil extracts of samples from the adsorption equilibrium test (48 h samples). From the recovery rates, ranging from 86.5% to 88.7% TAR, it was concluded that the test item was not stable during the test and, therefore, the direct method was used for adsorption isotherm determination.
For the isotherms determination test (with 24 h of agitation, except for La Gironda), mass balance of radioactivity was determined from the samples treated at the highest dose rate of 1.00 µg mL-1. The results ranged from 91.9% to 96.5% TAR indicating complete recovery of radioactivity

Executive summary:

The adsorption behaviour of 14C-M635H004 was investigated on five different European soils. The five soils covered a range of pH (in CaCl2) from 5.3 to 7.7, a range of organic carbon content from 0.66% to 1.97% and four different textural classes (USDA): sandy clay loam, loamy sand, sandy loam and silt loam.
For the determination of the adsorption isotherm, five different nominal concentrations of the test item were used: 1.00, 0.50, 0.10, 0.05 and 0.01 µg mL-1 . Soil to solution ratio was 1/1 at the beginning of the experiments.
The adsorption equilibrium time was determined to be 48 h for La Gironda soil and 24 h for the other soils.
As observed in the equilibrium test, the test item was not stable. The concentrations of the test item were determined in the supernatant solutions and in the extracts of the remaining soil at each stage (direct method).
Desorption experiments were not conducted because of the extraction of the soils during isotherm determination.
The material balance during isotherm determination ranged from 91.9% to 96.5% TAR.
From the measured isotherms, the Freundlich adsorption coefficient (KF) as well as the adsorption coefficient corrected for the organic carbon content (KFOC) and the Freundlich exponent (1/n) were determined. The KF values ranged from 0.082 to 0.564 mL g -1 with corresponding KFOC values from 9.31 to 28.64 mL g -1 and 1/n values from 0.88 to 1.05.
The resulting adsorption parameters were reliable based on statistical measures (p-values, correlation coefficients)