Chlorimuron ethyl

Phototransformation in air

Administrative data

Endpoint:

phototransformation in air

Type of information:

experimental study

Adequacy of study:

supporting 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:

no guideline followed

Principles of method if other than guideline:

Photolysis of the radiolabeled test substance was studied in sterilized aqueous solutions which were buffered to pH 5, 7, and 9. The degradation of the test substance solutions exposed to simulated sunlight was compared to degradation of control solutions maintained in darkness. The temperature of all test solutions was kept at 25°C.

GLP compliance:

no

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

Study design

Light source:

other: simulated sunlight

Light spectrum: wavelength in nm:

ca. 300 - ca. 450

Details on light source:

A bank of lights consisting of 6 fluorescent sunlamps alternating with 6 fluorescent black lamps spaced 2 inches between lamp centers was set 6 inches above the surface of the test solutions. The average light intensity (300-450 nm) was 45.5 watts/m2 at a distance of 6-1/2 inches below the lamps.

Duration of test at given test condition

Duration of test at given test condition 1

Duration:

10 d

Temp.:

25 °C

Initial conc. measured:

0.5 other: ppm

Duration of test at given test condition 2

Duration:

10 d

Temp.:

25 °C

Initial conc. measured:

5 other: ppm

Reference substance:

yes

Remarks:

ethyl 2-(aminosulfonyl)benzoate and 4-chloro-6-methoxy-2-pyrimidinamine

Results and discussion

Transformation products:

yes

Identity of transformation products

Identity of transformation products 1

No.:

#1

Reference

Reference substance name:

Unnamed

Identity of transformation products 2

No.:

#2

Reference

Reference substance name:

Unnamed

Identity of transformation products 3

No.:

#3

Reference

Reference substance name:

Unnamed

Applicant's summary and conclusion

Conclusions:

The photodegradation of the test substance proceeded rapidly with a first half-life of about 2 days in all solutions exposed to light. Degradation of the dark controls was dependent on the pH of the test solution with half-lives ranging from 18 days to greater than 30 days. At the most hydrolytically stable pH (i.e. pH 9), photolysis of the test substance resulted in ethyl 2-[[[[(4-hydroxy- 6-methoxy-pyrimidin-2 -yl)amino]carbonyl]amino]sulfonyl]benzoate, N-[10-oxo-10H-[4,1]-benzoxathiepin[3,2-d]-6-methoxy- pyrimidin-2-yl]urea, S,S-dioxide, and [2-[[(amino)-carbonyl]amino]-6-methoxy-4-pyrimidinyl] 2-sulfobenzoate.

Executive summary:

Photolysis of the radiolabeled test substance was studied in sterilized aqueous solutions which were buffered to pH 5, 7, and 9. The degradation of the test substance solutions exposed to simulated sunlight was compared to degradation of control solutions maintained in darkness. The temperature of all test solutions was kept at 25°C.

 

The photodegradation of the test substance proceeded rapidly with a first half-life of about 2 days in all solutions exposed to light. Degradation of the dark controls was dependent on the pH of the test solution with half-lives ranging from 18 days to greater than 30 days. At the most hydrolytically stable pH (i.e. pH 9), photolysis of the test substance resulted in ethyl 2-[[[[(4-hydroxy- 6-methoxy-pyrimidin-2 -yl)amino]carbonyl]amino]sulfonyl]benzoate, N-[10-oxo-10H-[4,1]-benzoxathiepin[3,2-d]-6-methoxy- pyrimidin-2-yl]urea, S,S-dioxide, and [2-[[(amino)-carbonyl]amino]-6-methoxy-4-pyrimidinyl] 2-sulfobenzoate.