kresoxim-methyl (ISO);methyl (E)-2-methoxyimino-[2-(o-tolyloxymethyl)phenyl]acetate

Biodegradation in water and sediment: simulation tests

Administrative data

Endpoint:

biodegradation in water: sediment simulation testing

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP guideline study

Data source

Reference

Reference 1

Reference Type:

study report

Title:

Unnamed

Year:

1993

Report date:

1993

Reference 2

Reference Type:

other: FOCUS calculation

Title:

Unnamed

Report date:

2008

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

other: BBA Guideline part IV, 5-1

Test guideline 2

Qualifier:

according to guideline

Guideline:

EPA Subdivision N Pesticide Guideline 162-4 (Aerobic Aquatic Metabolism)

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

methyl (2E)-2-methoxyimino-2-[2-[(2-methylphenoxy)methyl]phenyl]acetate

EC Number:

604-351-6

Cas Number:

143390-89-0

Molecular formula:

C18 H19 N O4

IUPAC Name:

methyl (2E)-2-methoxyimino-2-[2-[(2-methylphenoxy)methyl]phenyl]acetate

Details on test material:

- Name of test material (as cited in study report): [ring-A-14C]242009
- Lot No.: 39/149-1 and L48/92 (Z-isomer)
- Radiochemical purity: >= 95% (incl. Z-isomer 242010, which comprise ca. 10% of total radioactivity)
- Specific activity: 4.41 MBq/mg
- Locations of the label: ((E)-2-[2-(2-Methyl-[ring-U-14C]phenoxy)-methyl]phenyl-
2-(methoxyimido)acetic acid methyl ester ("ring-A-14C-labelled BAS 490 F")

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

natural water / sediment

Details on source and properties of surface water:

Water/sediment System #1:
- Location: stream "Großer Graben", near D-25361 Krempe/Elmshom in a marsh area surrounded by arable land and pastures
- Temperature at time of collection: 17 °C (water)
- pH at time of collection: 7.7
- Oxygen concentration initial: 9.8 – 9.9 mg/L
- Redox potential initial: 198 mV (water)
- TOC: 50 mg/L
- Water hardness: 3.8 mmol/L

Water/sediment System #2:
- Location: stream "Ohlau", near D-24632 Lentfohrden surrounded by pastures
- Temperature at time of collection: 14 °C
- pH at time of collection: 7.8
- Oxygen concentration initial: 10.4 – 10.8 mg/L
- Redox potential initial: 253 mV
- TOC: 28 mg/L
- water hardness: 1.3 mmol/L

Details on source and properties of sediment:

Water/sediment System #1:
- Location: stream "Großer Graben" , near D-25361 Krempe/Elmshom in a marsh area surrounded by arable land and pastures
- pH at time of collection: 7.1
- organic carbon: 3.2%
- cation exchange capacity [meq/100 g soil]: 20
- particle size:
< 0.002 mm = 18.3%
0.002-0.006 mm = 5%
0.006-0.02 mm = 10.3
0.02-0.063 mm = 29.8%
0.063-0.2 mm = 23%
0.2-0.63 mm = 11.7%
0.63-2 mm = 1.9%

Water/sediment System #2:
- Location: stream "Ohlau", near D-24632 Lentfohrden surrounded by pastures
- pH at time of collection: 6.3
- organic carbon: 0.11%
- cation exchange capacity [meq/100 g soil]: 2.5
- particle size:
< 0.002 mm = 0.7%
0.002-0.006 mm = 0.1%
0.006-0.02 mm = 0.1
0.02-0.063 mm = 0.4%
0.063-0.2 mm = 1.6%
0.2-0.63 mm = 82%
0.63-2 mm = 14.5%

Duration of test (contact time):

100 - 102 d

Initial test substance concentration

Initial conc.:

0.17 other: mg/kg

Based on:

act. ingr.

Parameter followed for biodegradation estimation:

radiochem. meas.

Details on study design:

THE TEST SOLUTION
- Preparation: 10.6 mg unlabelled test substance were dissolved in 5 ml acetonitrile. 1.0 ml of this solution (2.12 mg unlabelled test substance) was added to a solution containing 12.6 MBq [14C]-test substance; at the spec. radioactivity of 4.41 MBq/mg this is equivalent to 2.87 mg of the undiluted 14C-labelled test substance. This solution was made up to 25.0 ml, in total containing 4.99 mg 14C-labelled test substance.

TEST SYSTEM
- Culturing apparatus: incubation flasks equipped with a stirrer, a trap for volatile components and a septum allowing the introduction of gas
- Aerobic and anaerobic conditions: At 20 °C in the dark the water was slowly stirred. Thus, aerobic conditions are achieved in the water, whereas a gradient in the redox potential is found in parts of the sediment.
- Intervals of abiotic measurement: Dissolved oxygen, redox potential, temperature and pH in the water are measured at each sampling date
- Details of trap for CO2 and volatile organics: containing with paraffin oil impregnated quartz wool and soda lime
- Flask preparation: containing a sediment layer of 2.5 cm and a water layer of 6 cm. Placed on an orbital stirrer at 20 °C and allowed to equilibrate for ca. 3 weeks before 14C-labled substance was applied.
- Heat-sterilization: two of the flasks, before application, three times 30 min/212 °C on three successive days
- Number of culture flasks/system: 22 (2 flasks heat sterilized)
- Total flask weight: 580 g
- Test substance application: 0.5 ml acetonitrile solution with 14C-labelled test substance were applied to the flasks
- Test substance concentration/flask: 0.10 mg (0.17 mg/kg water)
- Radioactivity/flask: 258 kBq

Reference substance

Reference substance:

other: free acid of BAS 490 F (denominated BF 490-1)

Results and discussion

% Degradation

% Degradation 1

% Degr.:

8

Parameter:

CO2 evolution

Sampling time:

100 d

Remarks on result:

other: System "Krempe"

% Degradation 2

% Degr.:

10

Parameter:

CO2 evolution

Sampling time:

100 d

Remarks on result:

other: System "Ohlau"

Half-life of parent compound / 50% disappearance time (DT50)

Half-life of parent compound / 50% disappearance time (DT50) 1

Compartment:

entire system

DT50:

1.26 d

Type:

other: single first order

Remarks on result:

other: System "Krempe"; half-life estimated by FOCUS modelling

Half-life of parent compound / 50% disappearance time (DT50) 2

Compartment:

entire system

DT50:

1.36 d

Type:

other: single first order

Remarks on result:

other: System "Ohlau"; half-life estimated by FOCUS modelling

Half-life of parent compound / 50% disappearance time (DT50) 3

Compartment:

entire system

DT50:

1.5 d

Type:

(pseudo-)first order (= half-life)

Remarks on result:

other: System "Krempe" (DT90 = 6.5 d); half-life values based on measurements

Half-life of parent compound / 50% disappearance time (DT50) 4

Compartment:

entire system

DT50:

1.6 d

Type:

(pseudo-)first order (= half-life)

Remarks on result:

other: System "Ohlau" (DT90 = 6.6 d); half-life values based on measurements

Transformation products:

yes

Identity of transformation products

Identity of transformation products 1

No.:

#1

Reference

Reference substance name:

Unnamed

IUPAC name:

corresponding acid BF 490-1 (E-isomer)

Identifier:

common name

Identity:

corresponding acid BF 490-1 (E-isomer)

Identity of transformation products 2

No.:

#2

Reference

Reference substance name:

Unnamed

IUPAC name:

Z-isomer of the corresponding acid BF 490-1

Identifier:

common name

Identity:

Z-isomer of the corresponding acid BF 490-1

Identity of transformation products 3

No.:

#3

Reference

Reference substance name:

Unnamed

IUPAC name:

humins

Identifier:

common name

Identity:

humins

Identity of transformation products 4

No.:

#4

Reference

Reference substance name:

Unnamed

IUPAC name:

humic acids

Inventory number:

InventoryMultipleMappingImpl [inventoryEntryValue=EC 215-809-6]

Identifier:

common name

Identity:

humic acids

Identity of transformation products 5

No.:

#5

Reference

Reference substance name:

Unnamed

IUPAC name:

fulvic acids

Identifier:

common name

Identity:

fulvic acids

Details on transformation products:

- Corresponding acid BF 490-1, E-isomer: rapidly formed by hydrolysis and enzymatic or microbial action (radioactivity found in this acid was after 100 days slightly below 70% in both systems
- Z-isomer of the corresponding acid BF 490-1: Radioactivity found in this acid was after 100 days approx. 7% in both systems)
- Humins, humic acids and fulvic acids: 12% radioactivity in the sediment of the system "Krempe"