spirodiclofen (ISO);3-(2,4-dichlorophenyl)-2-oxo-1-oxaspiro[4.5]dec-3-en-4-yl 2,2-dimethylbutyrate

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:

BBA Part VI, 1-1

Version / remarks:

2nd edition

Deviations:

yes

Remarks:

Following BBA recommendations of 19 Jan. 1999 (Ref., Letter AP 40-27-01 Eh/Fg/59), 1 instead of 2 soils was used in the experiments.

GLP compliance:

yes

Details on sampling:

The soil was collected on 15 March 1999. It was passed through a 2 mm sieve and stored until
used, as described in the BBA Guideline (1990) and ISO/DIS 1036-6 (1992).

Test organisms (inoculum):

soil

Total exposure duration:

91 d

Test temperature:

20 ± 2°C

Organic carbon content (% dry weight):

0.7

Nitrogen content (% dry weight):

32.14

Details on test conditions:

Soil Treatment
Sieved soil was treated with either 10 g ground quartz sand/kg dry wt soil (control) or a mixture of quartz sand and the test item. (0.20 mg or 0.98 mg/kg dry wt soil). The samples were mixed in 3 liter polyethylene containers by rolling on a gyrowheel mixer (Elte 650, J. Engelsmann AG, Ludwigshafen, Germany) for 15 min at 50 rpm. In separate studies it was determined that mixing substances into soils as described gives a homogeneous and reproducible distribution (Blumenstock, 1989). Since the soil was not extracted and analyzed,
values given for the active ingredients are nominal.

Soil Incubation
After mixing, soil samples equivalent to 250 g dry weight were poured into 500 mL brown glass bottles and these were closed with parafilm. Three replicates were prepared per treatment. Each bottle was marked with an identification number and the quantity of product added to the soil. The soil was held in the dark at 20 ± 2 °C and about 40 % water capacity.

Reference substance (positive control):

yes

Remarks:

ARETIT FLÜSSIG

Key result

Duration:

91 d

Dose descriptor:

NOEC

Effect conc.:

0.98 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: Glucose Stimulated Soil Respiration

Results with reference substance (positive control):

ARETIT FLUSSIG® was provided as a reference standard by the Institute for Weed Research of the Federal Biological Institute for Agriculture and Forestry in Braunschweig, Germany In tests with an agricultural soil described in this report, the equivalents of 6 L/ha and 30 L/ha had distinct influences on the microbial activity for at least 91 days (Anderson, 1999).

Conclusions:

NOEC = 0.98 test item/kg soil dw

Executive summary:

During the 91-day experiments, 0.20 mg test item/kg soil dw (0.1477 kg test item/ha) and 0.98 mg test item/kg soil dw (0.7385 kg test item/ha) had no influence on respiration after adding glucose to the silty sand.

The data show that the product did not cause a change in the soil pH.

Reference 2

Endpoint:

toxicity to soil microorganisms

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Guideline:

BBA Part VI, 1-1

Version / remarks:

1990

Deviations:

yes

Remarks:

Following BBA recommendations of 19 Jan. 1999 (Ref., Letter AP 40-27-01 Eh/Fg/59), 1 instead of 2 soils was used in the experiments.

GLP compliance:

yes

Details on sampling:

The soil was collected on 15 March 1999. It was passed through a 2 mm sieve and stored until
used, as described in the BBA Guideline (1990) and ISO/DIS 1036-6 (1992).

Details on preparation and application of test substrate:

In this study, the equivalents of 0.1477 and 0.7385 kg test item/ha were added to samples
of an agricultural soil. To calculate the amount of substance to be applied per kg soil dw, a soil depth of 5 cm and a soil density of 1.5 g/cm³ were assumed (BBA Guideline 1990). Based on these values, 0.1477 and 0.7385 kg test item/ha corresponded to 0.20 and 0.98 mg test item/kg soil dw.

Test organisms (inoculum):

soil

Total exposure duration:

91 d

Test temperature:

20 ± 2 °C

Organic carbon content (% dry weight):

0.7

Nitrogen content (% dry weight):

32.14

Details on test conditions:

Soil Treatment
Sieved soil (2 mm) was treated with either 10 g ground quartz sand/kg soul dwl (control) or
a mixture of quartz sand and the test item (0.20 mg or 0.98 mg test item/kg soil dw). The samples were mixed with pulverized lucerne-grassgreen meal (5000 mg/kg soil dw) and quartz sand in 3 liter polyethylene containers by rolling on a gyrowheel mixer (Elte 650, J. Engelsmann AG, Ludwigshafen, Germany) for 15 min at 50 rpm. In separate studies it was determined that mixing substances into soils as described gives a homogeneous and reproducible distribution (Blumenstock, 1989). Since the soils were not extracted and analyzed, values given for the active ingredients are nominal.

Soil incubation
After mixing, soil samples equivalent to 250 g soil dw were poured into 500 mL brown glass
bottles and these were closed with parafilm. Three replicates were prepared per treatment.
Each bottle was marked with an identification number and the quantity of substance added to
the soil. The soil was held in the dark at 20 ± 2 °C and about 40 % water capacity.

Reference substance (positive control):

yes

Remarks:

Sodium cloride

Key result

Duration:

91 d

Dose descriptor:

NOEC

Effect conc.:

0.98 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

nitrate formation rate

Results with reference substance (positive control):

Sodium chloride was used as a reference standard in the experiments. In tests with the agricultural
soil described above, 4000, 8000 and 16000 mg NaCl/kg soul dw had distinct and long-term (> 28 days) influences on microbial mineralization of nitrogen. (Anderson, 1999).

Conclusions:

NOEC = 0.98 mg/kg soil dw

Executive summary:

During 91-day experiments, in a soil amended with lucerne-grass-green-meal (5000 mg/kg), it was found that 0.20 mg test item/kg dry wt soil (equivalent to 0.1477 kg test item/ha) and the 5-fold dose of the compound (0.98 mg test item/kg dry wt soil equivalent to 0.7385 kg test item/ha) had no influence on the turnover of nitrogen in a silty sand.

Nitrite formation was not detected in any of the soil samples.

Description of key information

Two GLP- and Guideline studies on toxicity on soil microorganisms were performed in 1999. In both studies a Long-term NOEC for soil microorganism of 0.98 mg/kg soil dw was determined. One of these studies was on the mineralisation of nitrogen in soils and the other one on glucose stimulated respiration in soils.

 

 

Key value for chemical safety assessment

Long-term EC10 or NOEC for soil microorganisms:

0.98 mg/kg soil dw