3-anilino-5-methyl-5-(4-phenoxyphenyl)-1,3-oxazolidine-2,4-dione;famoxadone (ISO)

Toxicity to soil microorganisms

Link to relevant study record(s)

Reference

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)

Version / remarks:

2000

Deviations:

no

Qualifier:

according to guideline

Guideline:

OECD Guideline 217 (Soil Microorganisms: Carbon Transformation Test)

Version / remarks:

2000

Deviations:

no

GLP compliance:

yes

Specific details on test material used for the study:

Purity: 97.3%
Batch: DPX-JE874-221

Analytical monitoring:

no

Vehicle:

yes

Remarks:

Acetone

Details on preparation and application of test substrate:

An amount of 25 mg of famoxadone technical was dissolved in 25 mL acetone. The final concentration of the stock solution was 1 g/L. Adequate amounts of this stock solution were applied onto quartz sand and the solvent was allowed to evaporate overnight. The quartz sand was mixed into the soil. Deionised water was added to the soil to reach the desired range of soil moisture, resulting in a final water content of 50 %- 51 % of the WHCmax. After the addition of lucerne meal (for nitrogen turnover) and the famoxadone technical containing quartz sand and deionised water (control) to the soil, the soil samples were thoroughly mixed and divided in 3 replicates each. Each treatment group contained soil equivalent to 1200 g (for the nitrogen turnover test) and 2400 g (for the short-term respiration test) of dry soil.

Test organisms (inoculum):

soil

Total exposure duration:

28 d

Test temperature:

20 ± 2°C

Moisture:

50-51%

Details on test conditions:

TEST SYSTEM
After treating the soil, three equally sized soil sub-samples from each treatment group were placed in appropriate plastic boxes: The boxes were covered by perforated lids to enable a slight, but sufficient air exchange and weighed for the determination of the starting weight.
The plastic boxes were incubated at 20 ± 2°C in the dark. Once a week, the amount of moisture loss was determined by re-weighing the boxes, and adding water to adjust vessels to the starting weight.

SOIL
One single, common, agricultural soil type was used for the study. A freshly sampled soil batch from the same site were used in test. The soil used m this study was according to the Guidelines and was taken from a fallow grass land near Rossdorf. The district authority was Dannstadt-Dieburg. The municipality was 64380 Rossdorf, Germany and the geographical position: was longitude 8° 45'28" E and latitude 49°51’53’’N. For at least two years prior to test initiation, no pesticides had been used on the soil. No organic or mineral fertilizer had been applied to the soils for two years prior to study initiation, respectively. The field was let rest since 2000.

Nominal and measured concentrations:

0.247 and 2.5 mg/kg soil

Reference substance (positive control):

yes

Remarks:

Dinoterb and Dinoterb Acetate are tested at least once a year.

Key result

Duration:

28 d

Basis for effect:

other: deviations from respiration rates

Remarks:

deviations in respiration rates compared to control soil were -4.85 % and 0.19 % for the test concentrations of 0.247 mg and 2.5 mg famoxadone technical /kg soil dry weight, respectively.

Remarks on result:

other: deviations in respiration rates were not significantly different

Details on results:

Nitrogen turnover:
The soil nitrate content was clearly below the 25 % trigger value given by the OECD 216 guideline throughout the test. At day 28, the difference from control was -2.33 % and -21.3 % for the test concentrations of 0.247 mg and 2.5 mg famoxadone techanical/kg soil dry, respectively. These concentrations were below the soil nitrate trigger of 25%, however, the upper concentration was statistically significant from the control. The rate of nitrate turnover in soil, calculated as the nitrate formation rate per day, was below the 25 % trigger value according to the OECD guideline 216 on each sampling date. On day 28, the nitrate formation rate differed by 7.1 % and 18.8 %from control for the test concentrations of 0.247 mg and 2.5 mg famoxadone technical/kg soil dry weight, respectively.

Short term respiration:
Famoxadone technical at rates equivalent to 180 g and 1800 g/ha (0.247 mg and 2.5 mg famoxadone technical/kg soil dry weight, respectively) had no significant effect on the shortterm, substrate-induced respiration. The soil respiration was clearly below the 25 % trigger value given by the OECD 216 guideline throughout the test. At the end of the 28 day study, the deviations in respiration rates compared to control soil were -4.85 % and 0.19 % for the test concentrations of 0.247 mg and 2.5 mg famoxadone technical /kg soil dry weight, respectively. These concentrations were not statistically significant.

Validity criteria fulfilled:

yes

Conclusions:

The impact of famoxadone technical on soil microbial nitrification processes is tolerable up to concentrations of 2.5 mg/kg soil dry weight. The impact of tamoxadone technical on soil microbial respiration processes is negligible up to concentrations of 2.5 mg/kg soil dry weight.
No long term effects were observed as evaluated according to OECD guidelines 216/217.

Executive summary:

The effects of famoxadone (DPX-JE874) technical on soil microflora were assessed in a test that measured nitrogen turnover and short-term respiration following an application of famoxadone technical to soil. The test was conducted in accordance with the OECD Guidelines 216 and

217. Famoxadone technical was incubated in a single loamy sand soil over a period of 28 days (short-term respiration and nitrogen turnover) at rates of 180 g and 1800 g famoxadone technical/ha, equivalent to 0.247 mg and 2.5 mg famoxadone technical /kg soil dry weight, respectively.

 

The soil nitrate content was clearly below the 25 % trigger value given by the OECD 216 guideline throughout the test. At day 28, the difference from control was -2.33 % and -21.3 % for the test concentrations of 0.247 mg and 2.5 mg famoxadone technical/kg soil dry, respectively. These concentrations were below the soil nitrate trigger of 25%, however, the upper concentration was statistically significant from the control.

 

The rate of nitrate turnover in soil, calculated as the nitrate formation rate per day, was below the 25 % trigger value according to the OECD guideline 216 on each sailing date. On day 28, the nitrate formation rate differed by 7.1 % and 18.8 % from control for the test concentrations of 0.247 mg and 2.5 mg famoxadone technical/kg soil dry weight,

respectively.

 

Famoxadone technical at rates equivalent to 180 g and 1800 g/ha (0.247 mg and 2.5 mg

famoxadone technical/kg soil dry weight, respectively) had no significant effect on the short term, substrate-induced respiration. The soil respiration was clearly below the 25 % trigger value given by the OECD 216 guideline throughout the test. At the end of the 28 day study, the deviations in respiration rates compared to control soil were -4.85 % and 0.19 % for the test concentrations of 0.247 mg and 2.5 mg famoxadone technical /kg soil dry weight, respectively. These concentrations were not statistically significant.

 

The impact of famoxadone technical on soil microbial nitrification processes is tolerable up to concentrations of 2.5 mg/kg soil dry weight. The impact of tamoxadone technical on soil microbial respiration processes is negligible up to concentrations of 2.5 mg/kg soil dry weight.

No long term effects were observed as evaluated according to OECD guidelines 216/217.

Description of key information

28-day Soil Microorganism Nitrogen Transformation Test and Carbon Transformation Test, impact of test substance on nitrification and respiration processes was negligible, OECD 216 and OECD 217, Reliability = 1

Key value for chemical safety assessment

Long-term EC10 or NOEC for soil microorganisms:

2.5 mg/kg soil dw

Additional information

The impact of famoxadone technical on soil microbial nitrification processes and respiration processes is tolerable up to concentrations of 2.5 mg/kg soil dry weight.