Pyrasulfotole

Biodegradation in water and sediment: simulation tests

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

biodegradation in water: sediment simulation testing

Type of information:

experimental study

Adequacy of study:

key study

Study period:

19 Dec 2003 - 28 Feb 2006

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 308 (Aerobic and Anaerobic Transformation in Aquatic Sediment Systems)

Version / remarks:

2002

Deviations:

yes

Remarks:

Untreated control samples were prepared, but not treated with organic solvent. The total OC in the water and sediment phases was not monitored at the start and end of each incubation period. No effect on the interpretation of study results.

Qualifier:

according to guideline

Guideline:

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

Deviations:

yes

Remarks:

Untreated control samples were prepared, but not treated with organic solvent. The total OC in the water and sediment phases was not monitored at the start and end of each incubation period. No effect on the interpretation of study results.

GLP compliance:

yes (incl. QA statement)

Radiolabelling:

yes

Oxygen conditions:

aerobic

Inoculum or test system:

natural water / sediment: freshwater

Details on source and properties of surface water:

- Details on collection:
Pikeville Water/Sediment System:
Pikeville, Wayne County, North Carolina, USA
Pond from agricultural use area
Collection Date: 12 Nov 2003
No pesticide was applied to or around within 5 years prior to collection.
Water was collected at 0 - 15 cm.
Lawrence Water/Sediment System:
Jefferson County, Kansas, USA
Pond from agricultural use area
Collection Date: 2004-01-23
No pesticide was applied to or around within 5 years prior to collection.
Water was collected at 0 - 15 cm.
- Storage conditions: Stored in walk-in refrigerator at ca. 4 °C
- Storage length: 30 and 19 days for the Pikeville and Lawrence systems, respectively.
- Temperature (°C) at time of collection: Pikeville: 19 °C; Lawrence: 3 °C
- pH at time of collection: Pikeville: 4.8; Lawrence: 7.5
- Electrical conductivity: Pikeville: 0.15 mmhos/cm; Lawrence: 0.48 mmhos/cm
- Redox potential (mv) initial/final: Pikeville: 373/597 mV; Lawrence: 279/287 mV
- Oxygen concentration initial/final: Pikeville: 5.7/5.7 mg/L; Lawrence: 6.7/6.1 mg/L
- Hardness (CaCO3): Pikeville: 18 ppm; Lawrence: 175 ppm
- Biomass:
Pikeville:
Initial: 44.0 x 10E+06 (cells/mL water)
During: 11.6 x 10E+06 (cells/mL water)
Final: 9.4 x 10E+06 (cells/mL water)
Lawrence:
Initial: 8.8 x 10E+06 (cells/mL water)
During: 5.2 x 10E+06 (cells/mL water)
Final: 11.3 x 10E+06 (cells/mL water)
- Water filtered: No

Details on source and properties of sediment:

- Details on collection:
Pikeville Water/Sediment System:
Pikeville, Wayne County, North Carolina, USA
Pond from agricultural use area
Collection Date: 2003-11-12
No pesticide was applied to or around within 5 years prior to collection.
Sediment was collected 15-40 cm.
Lawrence Sediment System:
Jefferson County, Kansas, USA
Pond from agricultural use area
Collection Date: 2004-01-23
No pesticide was applied to or around within 5 years prior to collection.
Sediment collected 0-15 cm.

- Storage conditions: Stored in walk-in refrigerator at ca. 4°C
- Storage length: 30 and 19 days for the Pikeville and Lawrence systems, respectively.

- Textural classification (i.e. %sand/silt/clay):
Pikeville:
64/32/4
Lawrence
11/50/39

- pH at time of collection: Pikeville: 5.4; Lawrence: 7.5
- Organic carbon (%): Pikeville: 4.1%; Lawrence: 0.81%
- CEC (meq/100 g): Pikeville: 5.0; Lawrence: 28.4
- Bulk density (g/cm³): Pikeville: 0.76; Lawrence: 1.15

- Biomass:
Pikeville:
Initial: 144 x 10E+06 (cells/g sediment)
During: 298 x 10E+06 (cells/g sediment)
Final: 441 x 10E+06 (cells/g sediment)
Lawrence:
Initial: 171.0 x 10E+06 (cells/g sediment)
During: 255 x 10E+06 (cells/g sediment)
Final: 196 x 10E+06 (cells/g sediment)

- Sediment samples sieved: Yes

Duration of test (contact time):

>= 131 - <= 132 d

Initial conc.:

3.83 µg/L

Based on:

act. ingr.

Remarks:

[pyrazole-3-14C] 1 x application rate; Pikeville

Initial conc.:

3.81 µg/L

Based on:

act. ingr.

Remarks:

[phenyl-UL-14C] 1 x application rate; Pikeville

Initial conc.:

3.78 µg/L

Based on:

act. ingr.

Remarks:

[pyrazole-3-14C] 1 x application rate; Lawrence

Initial conc.:

3.84 µg/L

Based on:

act. ingr.

Remarks:

[phenyl-UL-14C] 1 x application rate, Lawrence

Initial conc.:

19.3 µg/L

Based on:

act. ingr.

Remarks:

[pyrazole-3-14C] 5 x application rate; Pikeville

Initial conc.:

19.4 µg/L

Based on:

act. ingr.

Remarks:

[phenyl-UL-14C] 5 x application rate; Pikeville

Initial conc.:

19.1 µg/L

Based on:

act. ingr.

Remarks:

[pyrazole-3-14C] 5 x application rate; Lawrence

Initial conc.:

19.3 µg/L

Based on:

act. ingr.

Remarks:

[phenyl-UL-14C] 5 x application rate, Lawrence

Parameter followed for biodegradation estimation:

CO2 evolution

radiochem. meas.

Details on study design:

TEST CONDITIONS
- Volume of test solution/treatment:
[pyrazole-3-14C]:
Pikeville (1 x rate): 0.436 mL of 1.96 μg/mL test solution
Lawrence (1 x rate): 0.414 mL of 2.06 μg/mL test solution
[phenyl-UL-14C]:
Pikeville (1 x rate): 0.436 mL of 2.01 μg/mL test solution
Lawrence (1 x rate): 0.386 mL of 2.08 μg/mL test solution
[pyrazole-3-14C]:
Pikeville (5 x rate): 0.426 mL of 10.1 μg/mL test solution
Lawrence (5 x rate): 0.412 mL of 11.1 μg/mL test solution
[phenyl-UL-14C]:
Pikeville (5 x rate): 0.432 mL of 9.95 μg/mL test solution
Lawrence (5 x rate): 0.370 mL of 11.6 μg/mL test solution
- Composition of medium: Acetonitrile/water (1:1, v/v)
- Test temperature: 25 ± 2°C
- pH: Pikeville: 6.4; Lawrence: 8.0
- pH adjusted: No
- CEC: Pikeville: 5.0 meq/100 g; Lawrence: 28.4 meq/100 g
- Aeration of dilution water: Yes
- Continuous darkness: Yes
- Any indication of the test material adsorbing to the walls of the test apparatus: None

TEST SYSTEM
- Culturing apparatus: 500 mL glass flask, 21 cm long, 7.2 cm internal diameter equipped with impinging tube for aeration and volatile product collection.
- Number of culture flasks/concentration: Pikeville: 40; 20 (1x) + 20 (5x); Lawrence: 40; 20 (1x) +20 (5x)
- Method used to create aerobic conditions: Humidified air, regulated by a capillary flow-cell, entered each flask via an impinging tube.
- Method used to control oxygen conditions: Test systems were continuously purged with humidified air to ensure aerobic conditions. The pH, dissolved oxygen, and redox potential (E0) were monitored at harvest intervals. Water/sediment ratio: 3:1 (225 mL water:75 mL sediment)
- Measuring equipment: The dissolved oxygen was measured using an Orion dissolved oxygen meter. The pH and redox potential were measured using an IQ 400 solid state pH/mV/OPR meter

- Test performed in closed vessels due to significant volatility of test substance: No
- Test performed in open system: Yes
- Details of trap for CO2 and volatile organics if used: Test systems were continuously flushed with humidified air (flow-through system) at a rate of 10 to 20 mL/ min. The air exiting each flask then passed sequentially through an ethylene glycol trap (30 mL; Pikeville sediment system only) used for trapping VOC, followed by an ethanolamine trap (30 mL; Pikeville and Lawrence sediment systems) used for trapping [14C]O2. The amount of radioactivity in the volatile traps was determined by liquid scintillation counting (LSC) of triplicate aliquots. Volatile traps were sampled for radioactivity on the days that flasks were taken for extraction. Periodically, all traps were replaced with fresh traps to avoid potential losses from saturation.

SAMPLING
- Sampling frequency:
Pikeville: 0, 11, 26, 55, 81, 109, and 132 days post-application.
Lawrence: 0, 21, 42, 64, 83, 104, and 131 days post-application.
- Sampling method used per analysis type: Water decanted, entire sediment sample removed for extraction.
- Sample storage before analysis: Water layers and sediment were separated and sediment extracted on the day of collection. Water layers and sediment extracts were frozen (< 15 °C) up to 15 days prior to analysis.
- Other: Non-sterile untreated systems were taken for microbial biomass determinations after 0, 55, and 132 days after treatment (Pikeville) and 0, 60, and 131 days (Lawrence) after treatment.

STATISTICAL METHODS:
For each sampling interval, single replicates of each radiolabel and application rate were taken for analysis. Liquid samples were sub-sampled for LSC in triplicate and expressed as an average for further calculation. Extracted sediment samples were combusted in triplicate, and the relative standard deviation (RSD) was calculated from the weight corrected (per gram) LSC result. Samples with RSD >10% were repeated. LSC counts were measured for 5 minutes or to an error of 2% sigma, whichever was shorter. Characterization by HPLC of test substance was calculated from a mean of two replicates, one from each radiolabel. Characterization of test substance benzoic acid metabolite was determined from the single phenyl radiolabeled samples. The Q-test (rejection quotient) was used to determine if data could be rejected as statistical outliers at a 90% confidence limit. Standard deviations and relative standard deviations were calculated.

Two kinetics models were used describe the translocation and degradation of the test substance under aerobic aquatic conditions. To describe the behavior of the test substance in the total sediment-water system, a simple first-order (SFO) model was used. However, to adequately explain the behavior of the test substance in the water phase, a bi-exponential kinetic model was used.

Compartment:

natural water / sediment: freshwater

% Total extractable:

21

% Non extractable:

73.9

% CO2:

< 1

% Recovery:

94.8

Remarks on result:

other:

Remarks:

Mean material balance of radioactivity of [14C]test substance from aerobic water sediment system after 132 days: Pikeville sediment system 1X (expressed as percent of applied radiocarbon).

Compartment:

natural water / sediment: freshwater

% Total extractable:

20.2

% Non extractable:

72.6

% CO2:

< 1

% Recovery:

92.9

Remarks on result:

other:

Remarks:

Mean material balance of radioactivity of [14C]test substance from aerobic water sediment system after 132 days: Pikeville sediment system 5X (expressed as percent of applied radiocarbon).

Compartment:

natural water / sediment: freshwater

% Total extractable:

84

% Non extractable:

13

% CO2:

< 1

% Recovery:

97

Remarks on result:

other:

Remarks:

Mean material balance of radioactivity of [14C]test substance from aerobic water sediment system after 131 days: Lawrence sediment system 1X (expressed as percent of applied radiocarbon).

Compartment:

natural water / sediment: freshwater

% Total extractable:

88.8

% Non extractable:

10.6

% CO2:

< 1

% Recovery:

99.3

Remarks on result:

other:

Remarks:

Mean material balance of radioactivity of [14C]test substance from aerobic water sediment system after 131 days: Lawrence sediment system 5X (expressed as percent of applied radiocarbon). Mean total recovery after 131 days: 100.1%

Compartment:

natural water: freshwater

DT50:

38 d

Type:

other: Double First Order in Parallel

Temp.:

25 °C

Remarks on result:

other: Pikeville System

Compartment:

natural water: freshwater

DT50:

126.5 d

Type:

other: Double First Order in Parallel

Temp.:

12 °C

Remarks on result:

other:

Remarks:

Pikeville System; Calculated DT50, based on results at 25 °C.

Compartment:

natural water / sediment: freshwater

DT50:

69 d

Type:

other: Simple First Order

Temp.:

25 °C

Remarks on result:

other: Pikeville System

Compartment:

natural water / sediment: freshwater

DT50:

229.7 d

Type:

other: Simple First Order

Temp.:

12 °C

Remarks on result:

other:

Remarks:

Pikeville System; Calculated DT50, based on results at 25 °C.

Compartment:

natural water: freshwater

DT50:

327 d

Type:

other: Double First Order in Parallel

Temp.:

25 °C

Remarks on result:

other: Lawrence System

Compartment:

natural water: freshwater

DT50:

1 088.8 d

Type:

other: Double First Order in Parallel

Temp.:

12 °C

Remarks on result:

other:

Remarks:

Lawrence System; Calculated DT50, based on results at 25 °C.

Compartment:

natural water / sediment: freshwater

DT50:

578 d

Type:

other: first Order Non-linear

Temp.:

25 °C

Remarks on result:

other: Lawrence Sysyem

Compartment:

natural water / sediment: freshwater

DT50:

1 924.5 d

Type:

other: first Order Non-linear

Temp.:

12 °C

Remarks on result:

other:

Remarks:

Lawrence System; Calculated DT50, based on results at 25 °C.

Mineralization rate (in CO2):

0 other: Total percent of applied radioactivity at the end of the study.

Transformation products:

no

Remarks:

No major transformation products were detected in the water or sediment phases.

Details on transformation products:

- Formation and decline of each transformation product during test: No major transformation products were detected in the water or sediment phases. The sole minor transformation product was 2-methylsulfonyl-4-(trifluorormethyl)benzoic acid which did not exceed 3% in the total system of either water-sediment system.
- Pathways for transformation: test substance to test substance-benzoic acid metabolite and extractable or bound residues

Evaporation of parent compound:

no

Volatile metabolites:

no

Residues:

yes

Details on results:

TEST CONDITIONS
- Aerobicity, moisture, temperature and other experimental conditions maintained throughout the study: Yes

TRANSFORMATION PRODUCTS
- Range of maximum concentrations in % of the applied amount and day(s) of incubation when observed:
Test substance-benzoic acid
Pikeville (5 x rate):
Water: 0.6 - 2.2% AR on days 81 and 132, respectively
Sediment: 0.1 - 0.8% AR on days 55 and 132, respectively
Subtotal: 0.6 - 3.0% on days 81 and 132, respectively
Lawrence (5 x rate):
Water: 0.8 - 1.6% AR on days 42 and 104, respectively
Sediment: 0.4 -1.0% AR on days 42 and 104, respectively
Subtotal: 1.2 - 2.6% on days 42 and 104, respectively

- Range of maximum concentrations in % of the applied amount at end of study period:
Pikeville (5 x rate):
Water: 2.2% AR on day 132
Sediment: 0.8% AR on day 132
Subtotal: 3.0% on day 132

Lawrence (5 x rate):
Water: 1.0% AR on day 131
Sediment:0.6% AR on day 131
Subtotal: 1.6% on day 131

TOTAL UNIDENTIFIED RADIOACTIVITY (RANGE) OF APPLIED AMOUNT:
Pikeville (5 x rate):
Subtotal: 0.6% of AR on day 132
Lawrence (5 x rate):
Subtotal: 0.3% of AR on day 131

EXTRACTABLE RESIDUES
- % of applied amount at day 0:
Note: The mean Total Extractable Radioactivity does not equal the sum from the sub-totals of the test substance, the test substance-benzoic acid metabolite, and unidentified radioactivity
due to test substance-benzoic acid being formed only in the [phenyl-UL-14C]test substance samples.
Pikeville (5 x rate):
Water: 97.6
Sediment: 0.9
Subtotal: 98.5
Lawrence (5 x rate):
Water: 100.9
Sediment: 1.0
Subtotal: 101.9
- % of applied amount at end of study period:
Pikeville (5 x rate):
Water:7.1
Sediment 13.1
Subtotal: 20.2
Lawrence (5 x rate):
Water: 64.4
Sediment: 24.4
Subtotal: 88.8

NON-EXTRACTABLE RESIDUES
- % of applied amount at day 0:
Pikeville (5 x rate): 0.0
Lawrence (5 x rate): 0.5 ± 0.1
- % of applied amount at end of study period:
Pikeville (5 x rate): 72.6 ± 1.5
Lawrence (5 x rate): 10.6 ± 0.8

MINERALISATION
- % of applied radioactivity present as CO2 at end of study:
Pikeville (5 x rate): not detected < LOQ
Lawrence (5 x rate): 0.0

VOLATILIZATION
- % of the applied radioactivity present as volatile organics at end of study:
Pikeville (5 x rate): 0.1 ± 0.1
Lawrence (5 x rate): 0.0

For details on physicochemical characteristics of water-sediment test matrices, experimental design, sampling details, dissolved oxygen, pH and redox measurements, material balance of radioactivity and the biotransformation of the test substance see attachment.

Validity criteria fulfilled:

not applicable

Reference 2

Endpoint:

biodegradation in water: sediment simulation testing

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

03 Mar 2003 - 04 May 2005

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EPA Subdivision N Pesticide Guideline 162-3 (Anaerobic Aquatic Metabolism)

Deviations:

no

Qualifier:

according to guideline

Guideline:

other: Canada PMRA DACO Number 8.2.5.3.6

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Radiolabelling:

yes

Oxygen conditions:

anaerobic

Inoculum or test system:

natural water / sediment: freshwater

Details on source and properties of surface water:

Details on collection:
- Location: Jefferson County, Lawrence, KS, USA; Pond from agricultural use area, no pesticides used for previous five years
- Collection procedures: Water: 5 gallon buckets
- Sampling Depth: Water: 0-15.2 cm
- Storage conditions: 25 °C
- Storage length: 27 Days
- Temperature (°C) at time of collection: 5.8 °C
- pH at time of collection: 7.5
- Redox potential initial/final: -24.9/16.9 mV
- Oxygen concentration initial/final: 0.1/0.2 mg/L
- Hardness (CaCO3): 200 ppm
- Dissolved organic carbon: 11.7 ppm
- Biomass:
Initial: 1.17 x 10E+07 cells/mL water
Intermediate: 4.56 x 10E+06 cells/mL water
Final: 4.39 x 10E+06 cells/mL water
- Water filtered: No

Details on source and properties of sediment:

Details on collection:
- Location: Jefferson County, Lawrence, KS, USA; Pond from agricultural use area
- Use of pesticides: No pesticides used for previous five years
- Collection procedures: 5 gallon buckets with a shovel
- Sampling Depth: Water: Sediment 15.2 cm
- Storage conditions: 25 °C: sediment stored with a water layer on top.
- Storage length: 27 d
- Temperature (°C) at time of collection: 5.8 °C
- pH at time of collection: 7.0
- Organic carbon (%): 1.1
- CEC (meq/100 g): 35.7
- Bulk density (g/cm³): 1.19
- Biomass:
Initial: 2.89 x 10E+08 cells/g sediment
Intermediate: 2.75 x 10E+08 cells/g sediment
Final: 1.42 x 10E+08 cells/g sediment
- Sediment samples sieved: yes, wet sieved with 2.0 mm sieve.

Duration of test (contact time):

365 d

Initial conc.:

0.6 other: μg/test system

Based on:

act. ingr.

Remarks:

kinetic application solution

Initial conc.:

6 other: μg/test system

Based on:

act. ingr.

Remarks:

Metabolite Identification system (MID)

Parameter followed for biodegradation estimation:

CO2 evolution

radiochem. meas.

Details on study design:

TEST CONDITIONS
- Volume of test solution/treatment: water/sediment 150 mL/50 g dwt
- Composition of medium: Freshwater
- Solubilising agent: acetonitrile, the final concentration of which was < 0.1% in the test systems 0.120 mL/150 mL aqueous phase of the test system
- Test temperature: 20 ± 1 °C
- pH: the average pH of the test systems ranged from pH 6.6 - 7.0
- pH adjusted: No
- CEC:35.7 meq/100 g
- Aeration of dilution water: No
- Continuous darkness: Yes
- Any indication of the test material adsorbing to the walls of the test apparatus: No. The average material balance (average of two replicates) for the study ranged from 93.7 and 102.1% of the applied radioactivity throughout the duration of the study.
The mean material balance for the study was 96.6 ± 2.3%.

TEST SYSTEM
- Culturing apparatus:Silanized 250-mL Pyrex Erlenmeyer flask with side-arm and doublevalve
sealable top (or mineral oil bubblers during pre-incubation).
- Number of culture flasks/concentration: 2
- Method used to create anaerobic conditions: The test systems were equipped with mineral oil traps, flushed with
nitrogen, and acclimated in a nitrogen filled incubator.
- Method used to control oxygen conditions: Sealed test system.
- Measuring equipment: Control samples were
measured at each sampling interval throughout the study for pH, dissolved oxygen, and
redox potential.

- Test performed in closed vessels due to significant volatility of test substance: No.
- Test performed in open system: No. Sealed system; purged at
each sampling interval through 2 N KOH, ethylene glycol, 1 M H2SO4
- Details of trap for CO2 and volatile organics if used: Volatile
traps were comprised of six bubblers consisting of a blank, 30 mL of 2.0 M KOH
(potassium hydroxide), another 30 mL of 2.0 M KOH, 30 mL of ethylene glycol, 30 mL of
1 M sulfuric acid, and a blank.

SAMPLING
- Sampling frequency: 0, 3, 7, 10, 22, 31, 63, 92, 120, 183,
273 and 365 days post-application.
- Sampling method used per analysis type: Water decanted. Sediment shaken
with ACN:water (9:1 v:v), filtered and
extracted on ASE
- Sample storage before analysis: Stored in freezer below -15 ºC.

STATISTICAL METHODS:
A first-order nonlinear regression analysis was used to define the degradation rate
constant. A linear regression analysis was used to determine the
detector response (Microsoft Excel 2000). The Q-test (rejection quotient) was used to
determine if data could be rejected as statistical outliers, at a 90% confidence limit.
Sample standard deviations were also calculated.

Compartment:

natural water / sediment: freshwater

% Total extractable:

65.5

% Non extractable:

31.5

% CO2:

2.8

% Other volatiles:

0

Remarks on result:

other:

Remarks:

Material balance of radioactivity in the water/sediment system after 365 days. Total recovery after 365 days: 102.1%

Parent/product:

parent

Compartment:

total system

% Degr.:

2.8

Parameter:

radiochem. meas.

Sampling time:

365 d

Remarks on result:

other:

Remarks:

Mineralization to 14CO2 after 365 days.

Compartment:

natural water: freshwater

DT50:

84 d

Type:

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

Temp.:

20 °C

Compartment:

natural water: freshwater

DT50:

178.3 d

Type:

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

Temp.:

12 °C

Remarks on result:

other:

Remarks:

Calculated DT50 based on results at 20 °C.

Compartment:

natural water / sediment: freshwater

DT50:

273 d

Type:

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

Temp.:

20 °C

Remarks on result:

other: The data for the total system fit a biphasic model (r² =0.95), characterized by a fast dissipation rate resulting in a half life of 6.2 d for the first phase, and a slower dissipation rate resulting in a half-life for the second phase of greater than 1 yr

Compartment:

natural water / sediment: freshwater

DT50:

579.6 d

Type:

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

Temp.:

12 °C

Remarks on result:

other:

Remarks:

Calculated DT50 based on results at 20 °C.

Compartment:

natural water / sediment: freshwater

DT50:

6.2 d

Type:

other: biphasic (first phase)

Temp.:

20 °C

Compartment:

natural water / sediment: freshwater

DT50:

13.2 d

Type:

other: biphasic (first phase)

Temp.:

12 °C

Remarks on result:

other:

Remarks:

Calculated DT50 based on results at 20 °C.

Compartment:

natural water / sediment: freshwater

DT50:

> 1 yr

Type:

other: biphasic (second phase)

Temp.:

20 °C

Compartment:

natural water / sediment: freshwater

DT50:

> 1 yr

Type:

other: biphasic (second phase)

Temp.:

12 °C

Remarks on result:

other:

Remarks:

Calculated DT50 based on results at 20 °C.

Mineralization rate (in CO2):

2.8 other: %

Other kinetic parameters:

first order rate constant

other: biphasic

Transformation products:

no

Remarks:

No major transformation products were detected in the water or sediment phases.

Details on transformation products:

No major transformation products were detected in the water or sediment phases. The unidentified [14C] during the study was 3.1% on day 31 consisting of an average of three peaks, none of which were greater than 2.6% of the applied amount.

Evaporation of parent compound:

no

Volatile metabolites:

no

Residues:

yes

Details on results:

TEST CONDITIONS
- Anaerobicity, moisture, temperature and other experimental conditions maintained throughout the study: Yes

TOTAL UNIDENTIFIED RADIOACTIVITY (RANGE) OF APPLIED AMOUNT: 0 at day 365

EXTRACTABLE RESIDUES
- % of applied amount at day 0: 100 ± 0.4%
- % of applied amount at end of study period: 65.5 ± 5.6%

NON-EXTRACTABLE RESIDUES
- % of applied amount at day 0: 0%
- % of applied amount at end of study period: 33.8 ± 3.3%

MINERALISATION
- % of applied radioactivity present as CO2 at end of study: 2.8%

VOLATILIZATION
- % of the applied radioactivity present as volatile organics at end of study: 2.8%

Validity criteria fulfilled:

not applicable

Reference 3

Endpoint:

biodegradation in water: sediment simulation testing

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

03 Mar 2003 - 04 May 2005

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EPA Subdivision N Pesticide Guideline 162-3 (Anaerobic Aquatic Metabolism)

Deviations:

no

Qualifier:

according to guideline

Guideline:

other: Canada PMRA DACO Number 8.2.5.3.6

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Radiolabelling:

yes

Oxygen conditions:

anaerobic

Inoculum or test system:

natural water / sediment: freshwater

Details on source and properties of surface water:

- Details on collection: Jefferson County, Lawrence, KS, USA, 0-15.2 cm collected in 5 gallon buckets, no pesticide used for previous five years.
- Storage conditions: 25 °C
- Storage length: 27 days
- Temperature (°C) at time of collection: 5.8 °C
- pH at time of collection: 7.5
- Redox potential initial/final: -7.9/7.6 (Eh)
- Oxygen concentration initial/final: 0.3/0.1 mg/L
- Hardness (CaCO3): 200 ppm
- Dissolved organic carbon: 11.7 ppm
- Biomass:
Initial: 1.17 x 10E+07 cells/mL
Intermediate: 6.93 x 10E+06 cells/mL
Final: 5.45 x 10E+06 cells/mL
- Water filtered: No

Details on source and properties of sediment:

- Details on collection: Jefferson County, Lawrence, KS, USA, 0-15.2 cm collected in 5 gallon buckets, no pesticide used for previous five years.
- Storage conditions: 25 °C; sediment stored with a water layer on top.
- Storage length: 27 days
- Textural classification (i.e. %sand/silt/clay): Silt clay: Clay: 43.4%; Silt: 47.5% and Sand 9.1%
- pH at time of collection: 7.0
- Organic carbon: 1.1%
- CEC: 35.7 meq/100 g
- Bulk density (g/cm³): 1.19 g/cm³
- Biomass:
Initial: 2.89 x 10E+08 cells/g
Intermediate: 3.09 x 10E+08 cells/g
Final: 1.44 x 10E+08 cells/g
- Sediment samples sieved: Yes; wet sieved with 2 mm sieve

Duration of test (contact time):

365 d

Initial conc.:

0.6 other: µg/test system; 0.09 µCi

Based on:

act. ingr.

Initial conc.:

7.65 other: µg/test system; 1.14 µCi

Based on:

act. ingr.

Parameter followed for biodegradation estimation:

CO2 evolution

radiochem. meas.

Details on study design:

TEST CONDITIONS
- Volume of test solution/treatment: water/sediment 150 mL/50 g dwt
- Composition of medium: Freshwater
- Solubilising agent: acetonitrile, the final concentration of which was < 0.1% in the test systems 0.120 mL/150 mL aqueous phase of the test system
- Test temperature: 20 ± 1 °C
- pH: the average pH of the test systems ranged from pH 6.6 - 7.2
- pH adjusted: No
- CEC: 35.7 meq/100 g
- Aeration of dilution water: No
- Continuous darkness: Yes
- Any indication of the test material adsorbing to the walls of the test apparatus: No. The average material balance (average of two replicates) for the study ranged from 90.5 and 100.0% of the applied radioactivity throughout the duration of the study. The mean material balance for the study was 94.1 ± 2.8%.

TEST SYSTEM
- Culturing apparatus:Silanized 250-mL Pyrex Erlenmeyer flask with side-arm and doublevalve
sealable top (or mineral oil bubblers during pre-incubation).
- Number of culture flasks/concentration: 2
- Method used to create anaerobic conditions: The test systems were equipped with mineral oil traps, flushed with nitrogen, and acclimated in a nitrogen filled incubator.
- Method used to control oxygen conditions: Sealed test system.
- Measuring equipment: Control samples were measured at each sampling interval throughout the study for pH, dissolved oxygen, and redox potential.

- Test performed in closed vessels due to significant volatility of test substance: No.
- Test performed in open system: No. Sealed system; purged at each sampling interval through 2 N KOH, ethylene glycol, 1 M H2SO4
- Details of trap for CO2 and volatile organics if used: Volatile traps were comprised of six bubblers consisting of a blank, 30 mL of 2.0 M KOH (potassium hydroxide), another 30 mL of 2.0 M KOH, 30 mL of ethylene glycol, 30 mL of 1 M sulfuric acid, and a blank.

SAMPLING
- Sampling frequency: 0, 3, 14, 17, 28, 63, 91, 106, 120, 184, 275, and 365 days post-application.
- Sampling method used per analysis type: Water decanted. Sediment shaken with ACN:water (9:1 v:v), filtered and extracted on ASE
- Sample storage before analysis: Stored in freezer below -15 °C.

STATISTICAL METHODS:
A first-order nonlinear regression analysis was used to define the degradation rate constant. A linear regression analysis was used to determine the detector response (Microsoft Excel 2000). The Q-test (rejection quotient) was used to determine if data could be rejected as statistical outliers, at a 90% confidence limit. Sample standard deviations were also calculated.

Compartment:

natural water / sediment: freshwater

% Total extractable:

59.7

% Non extractable:

36.4

% CO2:

1.8

% Other volatiles:

0

% Recovery:

97.9

Remarks on result:

other:

Remarks:

Material balance of radioactivity in the water/sediment system after 365 days.

Parent/product:

parent

Compartment:

total system

% Degr.:

1.8

Parameter:

radiochem. meas.

Sampling time:

365 d

Remarks on result:

other:

Remarks:

Mineralization to 14CO2 after 365 days.

Compartment:

natural water

DT50:

75 d

Type:

other: First-order non-linear

Temp.:

20 °C

Remarks on result:

other: The fit of the data was not optimal (r² = 0.56)

Compartment:

natural water: freshwater

DT50:

159.2 d

Type:

other: First-order non-linear

Temp.:

12 °C

Remarks on result:

other:

Remarks:

Calculated DT50 based on results at 20 °C.

Compartment:

natural water / sediment: freshwater

DT50:

227 d

Type:

other: First-order non-linear

Temp.:

20 °C

Remarks on result:

other: The total system lon-linear fit was sub-optimal (r² = 0.56). The data for the total system better fit a biphasic model (r² = 0.95), resulting in a half life of 4.2 d for the first phase, and a half-life for the second phase of greater than 1 yr.

Compartment:

natural water / sediment: freshwater

DT50:

481.9 d

Type:

other: First-order non-linear

Temp.:

12 °C

Remarks on result:

other:

Remarks:

Calculated DT50 based on results at 20 °C.

Mineralization rate (in CO2):

1.8 other: % after 365 d

Other kinetic parameters:

first order rate constant

Transformation products:

no

Remarks:

No major transformation products were detected in the water or sediment phases.

Details on transformation products:

No major transformation products were detected in the water or sediment phases. The unidentified [14C] during the study was <1.6% on day 106 consisting of two peaks, none of which were greater than 0.9% of the applied amount.

Evaporation of parent compound:

no

Volatile metabolites:

no

Residues:

yes

Details on results:

TEST CONDITIONS
- Anaerobicity, moisture, temperature and other experimental conditions maintained throughout the study: Yes

TOTAL UNIDENTIFIED RADIOACTIVITY (RANGE) OF APPLIED AMOUNT: 0%

EXTRACTABLE RESIDUES
- % of applied amount at day 0: 100%
- % of applied amount at end of study period: 59.7 ± 1.1%

NON-EXTRACTABLE RESIDUES
- % of applied amount at day 0: 0%
- % of applied amount at end of study period: 36.4 ± 2.0%

MINERALISATION
- % of applied radioactivity present as CO2 at end of study: 1.8%

VOLATILIZATION
- % of the applied radioactivity present as volatile organics at end of study: 1.8%

Validity criteria fulfilled:

not applicable

Description of key information

DT50 of parent substance in water: 127 - 1089 days at 12 °C (aerobic, OECD 308, two water/sediment systems)

 

DT50 of parent substance in water/sediment: 230 - 1925 days at 12 °C (aerobic, OECD 308, two water/sediment systems, <1% mineralization after 132 days )

 

DT50 of parent substance in water: 178 days at 12 °C (anaerobic, EPA 162-3, one water/sediment system)

 

DT50 of parent substance in water/sediment: 580 days at 12 °C (anaerobic, EPA 162-3, one water/sediment system, 1.8% mineralization after 365 days )

 

Additional information

The aerobic biotransformation of [pyrazol-3-14C]-test substance and [phenyl-UL-14C]-test substance was studied in a pond water-sandy loam sediment system (water pH 6.4, sediment pH 5.4, organic carbon 4.1%) from Pikeville, North Carolina, USA, for 132 days and a pond water-silty clay loam sediment system (water pH 8.0, sediment pH 7.5, organic carbon 0.81%) from Lawrence, Kansas, USA, for 131 days (M-267001-01-2). Both sediments were incubated in the dark at 25 ± 1°C. [14C]test substance was applied at two rates of 3.8 and 19 μg a.i./L each. The experiment was conducted in accordance with the Pesticide Assessment Guidelines, Subdivision N, Environmental Fate, US EPA, 162-4 and in compliance with the GLP standards US EPA Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA): Good Laboratory Practice Standards. The test systems consisted of 500 mL straight-sided glass flasks containing sediment/water connected to a series of trapping solutions for the collection of CO2 and volatile products. Samples were analyzed at 0, 11, 26, 55, 81, 109, and 132 days of incubation in the sandy loam system and at 0, 21, 42, 64, 83, 104, and 131 days of incubation in the silty clay loam system. Water layers and sediment extracts were analyzed for [14C]test substance and its transformation products using reverse phase high performance liquid chromatography with 14C-radiodection. Identification of the parent compound was confirmed using LC/MS/MS.

Overall material balances averaged 96.8 ± 3.3% (range 89.8-101.9%, n=28) and 99.9 ± 1.9% (range 95.3-103.7%, n=28) in the water-sandy loam and water-silty clay loam sediment systems, respectively.

In the water-sandy loam sediment system, <1% of the applied radioactivity was present as either CO2 or organic volatile compounds at the end of the study.

In the water-silty clay loam sediment system, <0.1% of the applied radioactivity was present as either CO2 or organic volatile compounds at the end of the study.

In the water-sandy loam system, the percentage of [14C]test substance in water decreased from 97.6% at day 0 to 5.5% of the applied amount by the end of the study. The percentage of [14C]test substance in the sediment phase increased from 0.9% at day 0 to a maximum of 25.1% at day 26, before decreasing to 12.7% at the end of the study period. In the water-silty clay loam sediment system, the percentage of [14C]test substance in water decreased from 100.9% at day 0 to 63.9% of the applied amount by the end of the study. The percentage of [14C]test substance in the sediment phase increased from 0.5% at day 0 to 24.0% at the end of the study period.

No major transformation products were detected in the water or sediment phases. The sole minor transformation product was 2-methylsulfonyl-4-(trifluorormethyl)benzoic acid which did not exceed 3% in the total system of either water-sediment system

The 50% decline times (DT50) via biphasic kinetics of [14C]test substance in aerobic water were 38 and 327 days for the water-sandy loam and water-silty clay loam sediment systems, respectively (126.5 and 1088.8 days, recalculated to 12 °C). DT50 values using first-order non-linear kinetics of [14C]-test substance in the entire system were 69 and 578 the days for the water-sandy loam and water-silty clay loam sediment systems, respectively (229.7 and 1924.5 days, recalculated to 12 °C). 

The anaerobic biotransformation of radiolabeled test substance, was studied in a pond water/sediment system (water: pH 7.5, dissolved organic carbon = 11.7 ppm, sediment: texture = silty clay, pH 7.0, organic carbon = 1.1%) from Lawrence, Kansas, United States for 365 days in the dark at 20 ± 1 °C (M-250846-01-1). Test substance was applied at a rate of 0.004 mg a.i./L. The experiment was conducted in accordance with Pesticide Assessment Guidelines, Subdivision N, Environmental Fate, US EPA, 162-3, Environmental Chemistry and Fate, Guidelines for Registration of Pesticides in Canada, and in compliance with the GLP standards (40 CFR part 160; FR, August 17, 1989).

 At the end of the study, 1.8% and 0.0% of the applied radioactivity was present as CO2 and volatile organic compounds, respectively. No major transformation products were detected in the water or sediment phases. The half-lives using first-order nonlinear degradation kinetics for test substance in anaerobic water and in the entire system were 75 days (k = 0.0093 day-1; r2 = 0.56) and 227 days (k = 0.0031 day-1; r2 = 0.46), respectively (159.2 and 481.9 days, recalculated to 12 °C). The data for the total system better fit a biphasic model (r2 = 0.95), characterized by a fast dissipation rate (k = 0.167 day-1) resulting in a half-life of 4.2 days for the first phase, and a slower dissipation rate (k = 0.0004 day-1) resulting in a half-life for the second phase of greater than 1 year. There was no degradation of test substance in the anaerobic test system, but test substance dissipated to the sediment and formed bound residues.

 Anaerobic Aquatic Water/Sediment Systems [Phenyl UL-3 -14C]

The anaerobic biotransformation of radiolabeled test substance, was studied in a pond water/sediment system (water: pH 7.5, dissolved organic carbon = 11.7 ppm, sediment: texture = silty clay, pH 7.0, organic carbon = 1.1%) from Lawrence, Kansas, United States for 365 days in the dark at 20 ± 1 °C (M-250839-01-2). Test substance was applied at a rate of 0.004 mg a.i./L. The experiment was conducted in accordance with Pesticide Assessment Guidelines, Subdivision N, Environmental Fate, US EPA, 162-3, Environmental Chemistry and Fate, Guidelines for Registration of Pesticides in Canada, and in compliance with the GLP standards (40 CFR part 160; FR, August 17, 1989).

At the end of the study, 2.8% and 0.0% of the applied radioactivity was present as CO2 and volatile organic compounds, respectively.

The half-lives using first-order nonlinear degradation kinetics for test substance in anaerobic water and in the entire system were 84 days (k= 0.0083 day-1; r2 = 0.63) and 273 days (k = 0.0025 day-1; r2 = 0.40), respectively (178.3 and 579.6 days, recalculated to 12 °C). The data for the total system better fit a biphasic model (r2 = 0.95), characterized by a fast dissipation rate (k = 0.112 day-1) resulting in a half-life of 6.2 days for the first phase, and a slower dissipation rate (k =0.00007 day-1) resulting in a half-life for the second phase of greater than 1 year (13.2 days and >1 year, recalculated to 12 °C). There was no degradation of test substance in the anaerobic test system, but test substance dissipated to the sediment and formed bound residues.