diethyl 1-(2,4-dichlorophenyl)-5-methyl-4,5-dihydro-1H-pyrazole-3,5-dicarboxylate

Toxicity to soil microorganisms

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

toxicity to soil microorganisms

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 217 (Soil Microorganisms: Carbon Transformation Test)

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

no

Vehicle:

yes

Details on preparation and application of test substrate:

APPLICATION OF TEST SUBSTANCE TO SOIL
- Method: The test substance was thoroughly mixed with quartz meal because it is not water soluble. Subsequently the mixture was added to 1200 g soil dw and mixed in a mixing vessel in the laboratory. Water was added to the soil to achieve a water content of 45% of WHC (water holding capacity). The prepared soil was carried out in steel vessels. The soil was incubated in the dark at a temperature of 19.8 - 20.4°C in a climatic room for 28 days.

Test organisms (inoculum):

soil

Total exposure duration:

28 d

Test temperature:

19.8 - 20.4°C

Details on test conditions:

TEST SYSTEM
- Testing facility: Climatic room
- Test container (type, material, size): steel vessels (4 L)
- Amount of soil: 1200 g
- No. of replicates per concentration: 3
- No. of replicates per control: 3


SOURCE AND PROPERTIES OF SUBSTRATE (if soil)
- Geographical reference of sampling site (latitude, longitude): 12.694435960 degrees East/51.403774567 degrees North
- History of site:
- Vegetation cover: fallow ground
- Treatments with pesticides or fertilizers: Last application of plant protection products in 1990
- Depth of sampling: 20 cm
- Soil texture
- % sand: 50.2
- % silt: 39.6
- % clay: 10.2
- pH (in water): 6.6
- Initial nitrate concentration for nitrogen transformation test (mg nitrate/100 g dry weight): 0.48
- Maximum water holding capacity (g/100 g soil dw): 38.77
- Cation exchange capacity (cmol/kg soil dw): 10.1
- Pretreatment of soil: passed through a 2 mm mesh sieve
- Storage (condition, duration):
- Initial microbial biomass (mg C/100 g soil dw): 35.92 = 2.48% compared to C


EFFECT PARAMETERS MEASURED: Oxygen consumption

Nominal and measured concentrations:

Nominal concentrations: Control, 0.14, 0.70 mg test item/kg dry soil equivalent to 150 and 525 g test substance/ha
Test concentrations related to a soil depth of 5 cm and a soil density of 1.5 g/cm^3

Reference substance (positive control):

yes

Remarks:

2-tert-butyl-4,6-dinitrophenol

Duration:

28 d

Dose descriptor:

NOEC

Effect conc.:

0.7 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

respiration rate

Results with reference substance (positive control):

The test substance caused adverse effects (deviation from control >25%) on the soil carbon transformation (measured as oxygen consumption) at the end of the 28-day incubation period at concentrations of 16.00 and 27.00 mg/kg soil dw.

The test substance caused no adverse effects (deviation from control <25%) on the soil carbon transformation (measured as oxygen consumption) at the end of the 28-day incubation period. The study was performed in a field soil at concentrations equivalent up to a field application rate of 525 g test item/ha (0.70 mg test item/kg soil dw).

Reference 2

Endpoint:

toxicity to soil microorganisms

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 216 (Soil Microorganisms: Nitrogen Transformation Test)

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

no

Vehicle:

yes

Details on preparation and application of test substrate:

APPLICATION OF TEST SUBSTANCE TO SOIL
- Method: 150 g soil dry weight (soil dw) per test vessel was weighed. The soil was mixed with 0.5 % (i.e. 0.75 g/150 g soil d.w.) lucerne meal by means of a hand-stirrer. One additional soil sample (without lucerne meal) was used for determination of the initial NO3-N-content. The NO3-N content was 0.89 mg N/100 g soil dw. Because the water solubility of the test item was not available, it was thoroughly mixed with quartz meal. Subsequently, the obtained mixture was added and mixed with the soil by means of a hand-stirrer. Water was added to the soil to achieve a water content of 45 % of WHC.

Test organisms (inoculum):

soil

Total exposure duration:

28 d

Test temperature:

19.8 - 20.4°C

Moisture:

approx. 45% of its maximum water holding capacity

Details on test conditions:

TEST SYSTEM
- Testing facility: climate room
- Test container: wide mouth glass flasks (500 mL)
- Amount of soil: 150 g
- No. of replicates per concentration: 3
- No. of replicates per control: 3


SOURCE AND PROPERTIES OF SUBSTRATE
- Geographical reference of sampling site (latitude, longitude): 12.694435960 degrees East; 51.403774567 degrees North
- History of site:
- Vegetation cover: fallow ground
- Treatments with pesticides or fertilizers: none since 2003 (fertilisers); none since 1990 (plant protection products)
- Depth of sampling: 20 cm
- Soil texture
- % sand: 50.2
- % silt: 39.6
- % clay: 10.2
- pH (in water): 6.6
- Initial nitrate concentration for nitrogen transformation test (mg/100 g soil dry weight): 0.48
- Maximum water holding capacity (g/100 g soil dw): 38.77
- Cation exchange capacity (cmol/kg soil dw): 10.1
- Pretreatment of soil: passed through a 2 mm mesh sieve
- Initial microbial biomass (mg C/100 g soil dw): 35.92=2.48% compared to C



EFFECT PARAMETERS MEASURED: the nitrogen transformation was measured on day 0, 7, 21 and 28.

Nominal and measured concentrations:

Nominal concentrations: control - 0.14 - 0.70 mg test item/kg soil dw equivalent to 105 and 525 g test item/ha.
Test concentrations related to a soil depth of 5 cm and a soil density of 1.5 g/cm^3

Reference substance (positive control):

yes

Remarks:

2-tert-butyl-4,6-dinitrophenol

Duration:

28 d

Dose descriptor:

NOEC

Effect conc.:

0.7 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

nitrate formation rate

Results with reference substance (positive control):

AE F107892 caused adverse effects (deviation from control >25%, OECD 216) on the soil nitrogen transformation (measured as NO3 -N production) at the end of the 28-day incubation period at test concentrations of 6.8, 16.0 and 27.0 mg/kg soil dw.

AE F107892 caused no adverse effects (deviation from control <25%, OECD 216) on the soil nitrogen transformation (measured as NO₃ -N production) at the end of the 28-day incubation period. The study was performed in a field soil at concentrations equivalent up to a field application rate of 525 g/ha.

Description of key information

No adverse effects of the soil microorganisms.

Additional information

The toxicity of the substance to soil microorganisms was investigated in two OECD Guideline studies according to OECD 217 ( Soil Microorganisms: Carbon Transformation Test, 2006a) and OECD 216 (Soil Microorganisms: Nitrogen Transformation Test, 2006b).

The test substance caused no adverse effects (deviation from control <25%) on the soil carbon transformation (measured as oxygen consumption) or soil nitrogen transformation (measured as NO3-N production) at the end of the 28-day incubation period. The study was performed in a field soil at concentrations equivalent up to a field application rate of 525 g test item/ha. A NOEC (28 d) of 0.7 mg/kg soil dw (nominal) was determined for respiration rate and nitrate formation rate respectively.