Chlorimuron ethyl

Adsorption / desorption

Administrative data

Endpoint:

adsorption / desorption: screening

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

test procedure in accordance with national standard methods with acceptable restrictions

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1984

Report date:

1984

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

other: EPA 540/9-82-021

Deviations:

no

GLP compliance:

no

Type of method:

HPLC estimation method

Media:

soil

Test material

Test material information

Constituent 1

Reference substance name:

ethyl 2-({[(4-chloro-6-methoxypyrimidin-2-yl)carbamoyl]amino}sulfonyl)benzoate

EC Number:

618-690-2

Cas Number:

90982-32-4

Molecular formula:

C15H15ClN4O6S

IUPAC Name:

ethyl 2-({[(4-chloro-6-methoxypyrimidin-2-yl)carbamoyl]amino}sulfonyl)benzoate

Test material form:

solid

Remarks:

White

Details on test material:

95 to >99% purity

Radiolabelling:

yes

Study design

Test temperature:

25°C

HPLC method

Details on study design: HPLC method:

The mobility of the test substance was studied on each soil type by soil thin-layer chromatography. Each soil sample was hammer-milled to a 1-5 μm particle size and coated as a 400 μm layer onto 20 cm x 20 cm glass plates. One microliter aliquots of the sample and reference standard solutions (1 mg compound/mL acetone) were spotted three cm from the bottom of each plate. The lower 0.5 cm of each plate was submerged in water and the water was allowed to ascend to a height of 10 cm. The plates were air dried for 24 hours and exposed to X-ray film (Kodak SB-5) for two weeks.

Batch equilibrium or other method

Analytical monitoring:

no

Matrix properties

Matrix properties 1

Matrix no.:

#1

Matrix type:

sandy loam

% Clay:

18

% Silt:

21

% Sand:

61

% Org. carbon:

2.1

pH:

6.5

CEC:

6.6 meq/100 g soil d.w.

Matrix properties 2

Matrix no.:

#2

Matrix type:

silt loam

% Clay:

17

% Silt:

81

% Sand:

2

% Org. carbon:

4.3

pH:

5.4

CEC:

21.1 meq/100 g soil d.w.

Matrix properties 3

Matrix no.:

#3

Matrix type:

silt loam

% Clay:

5

% Silt:

83

% Sand:

12

% Org. carbon:

7.5

pH:

5.2

CEC:

15.5 meq/100 g soil d.w.

Matrix properties 4

Matrix no.:

#4

Matrix type:

sandy loam

% Clay:

7

% Silt:

33

% Sand:

60

% Org. carbon:

1.1

pH:

6.6

CEC:

5.3 meq/100 g soil d.w.

Results and discussion

Adsorption coefficient

Adsorption coefficient 1

Key result

Sample No.:

#1

Type:

other: Ka

Value:

0.43 other: µg/g

pH:

6.5

Temp.:

25 °C

Matrix:

Cecil sandy loam

% Org. carbon:

2.1

Adsorption coefficient 2

Key result

Sample No.:

#2

Type:

other: Ka

Value:

3.2 other: µg/g

pH:

5.4

Temp.:

25 °C

Matrix:

Flanagan silt loam

% Org. carbon:

4.3

Adsorption coefficient 3

Key result

Sample No.:

#3

Type:

other: Ka

Value:

7.4 other: µg/g

pH:

5.2

Temp.:

25 °C

Matrix:

Keyport silt loam

% Org. carbon:

7.5

Adsorption coefficient 4

Key result

Sample No.:

#4

Type:

other: Ka

Value:

0.19 other: µg/g

pH:

6.6

Temp.:

25 °C

Matrix:

Woodstown sandy loam

% Org. carbon:

1.1

Adsorption coefficient 5

Key result

Sample No.:

#1

Type:

Kd

Value:

0.96 other: µg/g

pH:

6.5

Temp.:

25 °C

Matrix:

Cecil sandy loam

% Org. carbon:

2.1

Adsorption coefficient 6

Key result

Sample No.:

#2

Type:

Kd

Value:

3.7 other: µg/g

pH:

5.4

Temp.:

25 °C

Matrix:

Flanagan silt loam

% Org. carbon:

4.3

Adsorption coefficient 7

Key result

Sample No.:

#4

Type:

Kd

Value:

0.24 other: µg/g

pH:

6.6

Temp.:

25 °C

Matrix:

Woodstown sandy loam

% Org. carbon:

1.1

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The test substance was very weakly adsorbed (Ka = 0.2-0.4) on the two sandy loam soils (Cecil sandy loam and Woodstown sandy loam) and only weakly adsorbed (Ka = 3-7) on the two silt loam soils (Flanagan silt loam and Keyport silt loam).

Executive summary:

Adsorption, desorption, and soil thin-layer chromatography studies were conducted on Cecil sandy loam, Flanagan silt loam, Keyport silt loam, and Woodstown sandy loam soils. The mobility of the test substance varied from low mobility (EPA Class 2) to mobile (EPA Class 4) based on the results of the soil thin-layer chromatography study. The Rf values were similar to those of terbacil but appeared to be more highly dependent on the percent organic matter content of the soil.

The test substance was very weakly adsorbed (Ka = 0.2-0.4) on the two sandy loam soils (Cecil sandy loam and Woodstown sandy loam) and only weakly adsorbed (Ka = 3-7) on the two silt loam soils (Flanagan silt loam and Keyport silt loam).

 

Adsorbed radioactivity was readily desorbed for the sandy loam soils (Cecil sandy loam and Woodstown sandy loam) but more tightly retained on the silt loams. This ease of desorption appears to be inversely proportional to the percent organic matter content of the soils (Flanagan silt loam and Keyport silt loam).

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