O-(4-bromo-2-chlorophenyl) O-ethyl S-propyl phosphorothioate

Biodegradation in soil

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

biodegradation in soil: simulation testing

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Performed to current OECD guidelines and to GLP.

Qualifier:

according to guideline

Guideline:

OECD Guideline 307 (Aerobic and Anaerobic Transformation in Soil)

GLP compliance:

yes

Test type:

laboratory

Radiolabelling:

yes

Oxygen conditions:

aerobic

Soil classification:

USDA (US Department of Agriculture)

Details on soil characteristics:

Clay, Clay, Loamy Sand, Clay

Soil No.:

#1

Temp.:

20oC

Microbial biomass:

0.69 mg C/kg

Soil No.:

#2

Temp.:

20oC

Microbial biomass:

0.27 mg C/kg

Soil No.:

#3

Temp.:

20oC

Microbial biomass:

0.10 mg C/kg

Soil No.:

#4

Temp.:

20oC

Microbial biomass:

0.23 mg C/kg

Soil No.:

#1

% Degr.:

6.82

Parameter:

radiochem. meas.

Sampling time:

120 d

Soil No.:

#2

% Degr.:

5.71

Parameter:

radiochem. meas.

Sampling time:

120 d

Soil No.:

#3

% Degr.:

4.87

Parameter:

radiochem. meas.

Sampling time:

120 d

Soil No.:

#4

% Degr.:

5.83

Parameter:

radiochem. meas.

Sampling time:

120 d

Soil No.:

#1

DT50:

13 d

St. dev.:

0.98

Type:

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

Remarks on result:

other: DT90 43.20 days

Soil No.:

#1

DT50:

11.57 d

St. dev.:

0.99

Type:

other: FOTC

Remarks on result:

other: DT90 69.84 days

Soil No.:

#2

DT50:

6.25 d

St. dev.:

0.98

Type:

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

Remarks on result:

other: DT90 20.78 days

Soil No.:

#2

DT50:

5.82 d

St. dev.:

0.99

Type:

other: FOTC

Remarks on result:

other: DT90 30.75 days

Soil No.:

#3

DT50:

9.33 d

St. dev.:

0.97

Type:

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

Remarks on result:

other: DT90 30.99 days

Soil No.:

#3

DT50:

8.97 d

St. dev.:

0.99

Type:

other: FOTC

Remarks on result:

other: DT90 56.23 days

Soil No.:

#4

DT50:

8.79 d

St. dev.:

0.95

Type:

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

Remarks on result:

other: DT90 29.22

Soil No.:

#4

DT50:

5.87 d

St. dev.:

0.99

Type:

other: FOTC

Remarks on result:

other: DT90 69.98 days

Transformation products:

yes

No.:

#1

Details on transformation products:

CA217 maximum 0.55%

Volatile metabolites:

yes

Residues:

yes

Details on results:

CO2 maximum of 74.78% (mean of duplicate samples)Organic volatiles maximum of 0.2% (mean of duplicate samples)Bound residues maximum of 41.1% (mean of duplicate samples)

Mean mass balances were between 90.28 and 103.31%

Conclusions:

This is a well documented study perforned to current guidelines and GLP.

Executive summary:

An OECD 307 guideline and GLP study on 4 Brazilian soils was perfomed. Results show that the DT50 for profenofos ranged from 5.82 to 11.6 days. Significant pathway of the breakdown of profenofos is to carbon dioxide (52.4 to 74.8%) and bound residues (22.4 to 41.1%). Mean DT50 of 8.1 days.

Reference 2

Endpoint:

biodegradation in soil

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

GLP compliance:

no

Remarks:

Pre GLP

Test type:

laboratory

Radiolabelling:

yes

Oxygen conditions:

aerobic/anaerobic

Details on soil characteristics:

Clay Loam, pH 7.5, %OM 3.4%, water content 16%.

Soil No.:

#1

Initial conc.:

4 ppm

Based on:

act. ingr.

Soil No.:

#1

Temp.:

21oC

Humidity:

55%

Details on experimental conditions:

Flasks were illuminated for 14 hours/day. Volatile CO2 was trappd in 2N NaOH

Soil No.:

#1

% Degr.:

1.6

Parameter:

radiochem. meas.

Sampling time:

4 wk

Soil No.:

#2

% Degr.:

0.1

Parameter:

radiochem. meas.

Sampling time:

12 wk

Soil No.:

#3

% Degr.:

0.1

Parameter:

radiochem. meas.

Sampling time:

12 wk

Soil No.:

#4

% Degr.:

0

Parameter:

radiochem. meas.

Sampling time:

12 wk

Transformation products:

yes

No.:

#1

Evaporation of parent compound:

not measured

Volatile metabolites:

not measured

Residues:

yes

Details on results:

Only CO2 was trapped (up to 25.6% aerobic after 12 weeks and 19.8% anaerobic after 12 weeks likely to be released during the 4 week aerobic phase). Very little CO2 released in the autoclaved samples implying microbial activity involved in breakdown of parent.

Non-extractables ranged from 18.1% in the autoclaved samples to 73.1% in the aerobic samples.

Mass Balances ranged from 89.1% to 98.2%

Conclusions:

This study can be used as supporting evidence to show the rapid breakdown of profenofos but cannot be used quantitatively.

Executive summary:

The aerobic and anaerobic degradation of CGA 15324 was studies in one clay loam soil under 4 experimental conditions. Results show that the degradation of CGA 15324 is rapid with 1.6% remaining after 4 weeks. CO2 and unextracted residues were the main degradation products. One metabolite C13565 was identified in small amounts in the non-sterile soils and at 65% in the autoclaved soils.

Small amounts of unidentified polar material also found.

Reference 3

Endpoint:

biodegradation in soil

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

comparable to guideline study

Qualifier:

according to guideline

Guideline:

other: US EPA Pesticide Assessment Guidelines 162-2

GLP compliance:

yes

Test type:

laboratory

Radiolabelling:

yes

Oxygen conditions:

aerobic/anaerobic

Details on soil characteristics:

Sandy Loam soil from California.

Soil No.:

#1

Initial conc.:

10.9 ppm

Based on:

test mat.

Soil No.:

#1

Temp.:

25oC

Humidity:

75%

Microbial biomass:

6.5E+6 CFU

Details on experimental conditions:

Units incubated in the dark at 25 +/- 1 degree C at 75% of its moisture capacity.

Soil No.:

#1

% Degr.:

57.6

Parameter:

test mat. analysis

Sampling time:

0 d

Soil No.:

#1

% Degr.:

10

Parameter:

test mat. analysis

Sampling time:

7 d

Soil No.:

#1

% Degr.:

1.5

Parameter:

test mat. analysis

Sampling time:

60 d

Soil No.:

#1

DT50:

2.9 d

St. dev.:

-0.978

Type:

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

Temp.:

25 °C

Transformation products:

yes

No.:

#1

No.:

#2

Details on transformation products:

CGA-55960 increased from 35% to 78.6% in 7 days to a maximum of 82.5% at 60 days.4-bromo-2-chlorophenyl ethyl ether reached a maximum of 2.7% at 2 days.Two polar componants reached a maximum of 5.8% at 30 days and declined to 3% at 60 days.

Evaporation of parent compound:

not measured

Volatile metabolites:

no

Residues:

yes

Details on results:

Unextracted residues reached a maximum of 4.8%.

Conclusions:

A well documented anaerobic study in 1 soil which gives a DT50 of profenofos in anaerobic conditions of 2.9 days,

Executive summary:

The anaerobic rate of degradation of profenofos was determined in one sandy loam soil to EPA guidelines and GLP.

The DT50 under anaerobic conditions was determined to be 2.9 days.

One major metabolite was formed CGA- 55960 at a maximum of 82.5% at 60 days. No significant CO2 produced (0.2%) and unentractable residues reached a maximum of 4.8%.

Reference 4

Endpoint:

biodegradation in soil

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

3 (not reliable)

Rationale for reliability incl. deficiencies:

other: Not carried out to modern guidelines, no mass balance, very brief description of methods.

Qualifier:

no guideline followed

Principles of method if other than guideline:

Two soils treated with 2ppm profenofos and extracted and analysed for the active ingredient at various intervals.

GLP compliance:

no

Test type:

laboratory

Radiolabelling:

no

Oxygen conditions:

other: Air exchange

Soil classification:

not specified

Details on soil characteristics:

Soil 1: pH 6.5, %OC 2.2, % clay 8.9, % silt 7.3, % sand 83.8Soil2: pH 4.8, %OC 1.1, % clay 10.5, % silt 12.4, % sand 77.1

Soil No.:

#1

Initial conc.:

1.5 ppm

Based on:

act. ingr.

Soil No.:

#2

Initial conc.:

2.02 ppm

Based on:

act. ingr.

Soil No.:

#1

Temp.:

22oC

Humidity:

40%

Microbial biomass:

NS

Soil No.:

#2

Temp.:

22oC

Humidity:

40%

Microbial biomass:

NS

Soil No.:

#1

% Degr.:

92

Parameter:

test mat. analysis

Sampling time:

64 d

Soil No.:

#2

% Degr.:

73

Parameter:

test mat. analysis

Sampling time:

64 d

Soil No.:

#1

DT50:

4.34 d

Type:

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

Remarks on result:

other: DT90 14.4 days

Soil No.:

#2

DT50:

41.15 d

Type:

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

Remarks on result:

other: DT90 136.7 days

Transformation products:

not measured

Evaporation of parent compound:

not measured

Volatile metabolites:

not measured

Residues:

not measured

Details on results:

Only the amount of test substance remaining in the soil was measured.

DT50 values were calculated separately using KinGui with SFO kinetics. Chi-square were 24.5 for soil 1 and 5.2 for soil 2.

Results in the report give ppm of active ingredient in the soil at 0, 4, 8, 21, 32 and 64 days.

For soil 1 CGA-15324 declines from 1.50 ppm (0% loss) to 0.59 ppm (61% loss) at 4 days to 0.12 ppm (92% loss) at 64 days.

For soil 2 CGA-15324 declines from 2.02 ppm (0% loss) to 1.29 ppm (36% loss) at 32 days to 0.54 ppm (73% loss) at 64 days.

Conclusions:

This study was not carried out to any guideline and is pre-GLP. Only the amount of test substance in the soil is reported. Volatiles were not trapped, bound residue was not quantified and no metabolites were identified. The data presented was used to calculate soil DT50's which could be used to support other studies.

Executive summary:

A degradation study on two soils which analysed the amount of CGA 15324 in soil over 64 days.

CGA 15324 declined by 73 to 92% in 64 days.

Volatiles were not collected and bound residue and metabolite identification not perfomed.

Description of key information

Profenofos shows rapid degradation in soil. The mean DT50 from the key aerobic study is 8.1 days.

Key value for chemical safety assessment

Half-life in soil:

8.1 d

at the temperature of:

20 °C

Additional information

An OECD 307 guideline and GLP study on 4 Brazilian soils (Barizon, 2007) show that the DT50 for profenofos ranged from 5.82 to 11.6 days. Significant pathway of the breakdown of profenofos is to carbon dioxide (52.4 to 74.8%) and bound residues (22.4 to 41.1%). Mean DT50 of 8.1 days.

In anaerobic conditions the degradation of profenofos is quicker with a DT50 of 2.9 days (Das, 1991).

Two supporting studies by Keller (1975) and Laanio (1975) also show that degradation of profenofos is fairly rapid with DT-50's of 4 to 41 days. The Laanio (1975) study showed 1.6% of profenofos remaining after 4 weeks of incubation.