Methanesulfonamide, N-[2-[(4,6-dimethoxy-1,3,5-triazin-2-yl)carbonyl]-6-fluorophenyl]-1,1-difluoro-N-methyl-

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

Study period:

18 Feb - 02 Jun 2010

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP Guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 216 (Soil Microorganisms: Nitrogen Transformation Test)

Version / remarks:

2000

GLP compliance:

yes (incl. QA statement)

Remarks:

Ministerium für Arbeit, Gesundheit und Soziales des Landes Nordrhein-Westfalen

Analytical monitoring:

no

Details on sampling:

Immediately after treatment and after 7, 14 and 28 days, the soil in each bottle was mixed by shaking. A moist sample, corresponding to 10 g dry weight, was removed and extracted with 50 mL 1 M-KCl by agitating for 60 minutes on a horizontal shaker at approximately 150 strokes/min. Soil particles were removed by filtration and the extracts analyzed for their content of ammonium-N, nitrite-N and nitrate-N plus nitrite- N. Soil extracts, which could not be analyzed immediately, were stored frozen.

Vehicle:

no

Details on preparation and application of test substrate:

900 g dry weight sieved soil (2 mm) was treated with either 10 g ground quartz sand/kg dry weight soil (control) or a mixture of quartz sand and test item (0.07 mg a.s. or 0.72 mg a.s./kg dry weight soil). The samples were mixed with pulverized Lucerne-grass-green meal (5 g/kg dry weight soil) and quartz sand in 3 litre polyethylene containers by rolling on a gyro wheel 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.

Test organisms (inoculum):

soil

Total exposure duration:

28 d

Test temperature:

20 ± 2 °C

Moisture:

40-50 % of the maximum water holding capacity

Details on test conditions:

TEST SYSTEM
- Testing facility: Bayer CropScience AG Development Environmental Safety, Ecotoxicology, Monheim, Germany
- Test container (type, material, size): 500 mL brown glass bottles, closed with Para film
- Amount of soil: 300 g soil dry weight
- No. of replicates per concentration: 3
- No. of replicates per control: 3

SOIL INCUBATION
- Method: A moist sample, corresponding to 10 g dry weight, was removed for the measurements. Immediately after treatment and after 7, 14 and 28 days, the soil in each bottle was mixed by shaking.

SOURCE AND PROPERTIES OF SUBSTRATE (if soil)
- Geographical reference of sampling site (latitude, longitude): Germany/Rheinland-Pfalz/Offenbach
- History of site: uncultivated since 2006
- Treatments with pesticides or fertilizers: none since 2006
- Depth of sampling: 0 - 20 cm
- Soil preparation: sieved to a particle size of < 2 mm
- Soil texture
- % sand: 62.6
- % silt: 28.1
- % clay: 9.3
- Soil taxonomic classification: loamy sand
- pH (in water): 7.53
- Initial nitrate concentration for nitrogen transformation test: Nmin = 110 mg/100 g dry weight soil
- Organic Carbon: 1.37%
- Biomass: 315 mg microbial C / kg dry weight soil (2.3 % of soil organic carbon content)
- Cation exchange capacity (meq/100 g dry weight soil): 14.9

Nominal and measured concentrations:

Nominal test concentrations: 0.07 mg and 0.72 mg a.s./kg dry weight soil

Reference substance (positive control):

yes

Remarks:

Sodium chloride

Duration:

28 d

Dose descriptor:

other: trigger value of 25% inhibition compared with the control

Effect conc.:

> 0.72 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

nitrate formation rate

Details on results:

The test item caused a temporary stimulation of the daily nitrate rates at the time interval 0-7 days after treatment. At the end of the test (14-28 day interval), differences in the nitrate-N rates between control soil samples and treated soil samples are below the trigger value of 25 % deviation.

Results with reference substance (positive control):

16 g Sodium chloride/kg dry weight soil had a distinct and long-term (> 28 days) influence on microbial mineralization of nitrogen. This shows that the test organisms are sufficiently sensitive.

Nitrite formation was not detected in any of the soil samples. The highest difference between nitrate-N rates per day of control and the treated soil samples was 468 % (0-7 days after soil treatment).

Table 1: Effects on soil microorganisms

	Control Nitrate-N	0.07 mg/kg a.s. Nitrate-N	difference to control	0.72 mg/kg a.s. Nitrate-N	difference to control
0-7 days	-0.02 ± 0.03	-0.10 ± 0.05	468%	-0.06 ± 0.08	241%
7-14 days	1.65 ± 0.07	1.38 ± 0.21	17%	1.50 ± 0.12	9%
14-28 days	0.84 ± 0.11	0.83 ± 0.04	2%	0.86 ± 0.08	1%

 

The pH-values measured at the beginning and end of the test. The data show that the product did not cause a change in soil pH.

The soil moisture were between 40-50 % of the maximum water holding capacity and in the range recommended by the guideline.

Reference 2

Endpoint:

toxicity to soil microorganisms

Type of information:

experimental study

Adequacy of study:

key study

Study period:

18 Feb - 02 Jun 2010

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP Guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 217 (Soil Microorganisms: Carbon Transformation Test)

Version / remarks:

2000

GLP compliance:

yes (incl. QA statement)

Remarks:

Ministerium für Arbeit, Gesundheit und Soziales des Landes Nordrhein-Westfalen

Analytical monitoring:

no

Vehicle:

no

Details on preparation and application of test substrate:

Sieved soil (2 mm) was treated with either 10 g ground quartz sand/kg dry weight soil (control) or a mixture of quartz sand and test item (0.07 mg a.s. or 0.72 mg a.s./kg dry weight soil). The samples were mixed in 3 litre polyethylene containers by rolling on a gyro wheel 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.

Test organisms (inoculum):

soil

Total exposure duration:

28 d

Test temperature:

20 ± 2 °C

Moisture:

40-50 % of the maximum water holding capacity

Details on test conditions:

TEST SYSTEM
- Testing facility: Bayer CropScience AG Development Environmental Safety, Ecotoxicology, Monheim, Germany
- Test container (type, material, size): 500 mL brown glass bottles, closed with perforated plastic lids
- Amount of soil: 350 g soil dry weight
- No. of replicates per concentration: 3
- No. of replicates per control: 3

SOIL INCUBATION
- Method: To determine the influence of the test item on glucose stimulated soil respiration, moist samples (equivalent to 25 g dry weight) were taken from each treatment on day 0, and after 7, 14 and 28 days of incubation. The samples were mixed with enough glucose to induce maximum respiration rates and poured into plastic cylinders (3 cm diameter, 23 cm long). The cylinders were connected to a gas analyzer (Wösthoff Co., Bochum, Germany) and the quantities of carbon dioxide released per hour per kg dry weight soil were measured for at least 12 hours.

SOURCE AND PROPERTIES OF SUBSTRATE (if soil)
- Geographical reference of sampling site (latitude, longitude): Germany/Rheinland-Pfalz/Offenbach
- History of site: uncultivated since 2006
- Treatments with pesticides or fertilizers: none since 2006
- Depth of sampling: 0 - 20 cm
- Soil preparation: sieved to a particle size of < 2 mm
- Soil texture
- % sand: 62.6
- % silt: 28.1
- % clay: 9.3
- Soil taxonomic classification: loamy sand
- pH (in water): 7.53
- Initial nitrate concentration for nitrogen transformation test: Nmin = 110 mg/100 g dry weight soil
- Organic Carbon: 1.37%
- Biomass: 315 mg microbial C / kg dry weight soil (2.3 % of soil organic carbon content)
- Cation exchange capacity (meq/100 g dry weight soil): 14.9

Nominal and measured concentrations:

Nominal test concentrations: 0.07 mg and 0.72 mg a.s./kg dry weight soil

Reference substance (positive control):

yes

Remarks:

Sodium chloride

Duration:

28 d

Dose descriptor:

other: trigger value of 25% inhibition compared with the control

Effect conc.:

> 0.72 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

respiration rate

Details on results:

After an exposure of 28 days, the difference in the carbon dioxide production does not exceed the trigger value of 25 % (mentioned in the guideline). Even though a statistically significant difference to the control at the end of the test occured, the deviation from the control was still below the
threshold value recommended by the guideline.

Results with reference substance (positive control):

16 g Sodium chloride/kg dry weight soil had a distinct and long-term (> 28 days) influence on microbial mineralization of nitrogen. This shows that the test organisms are sufficiently sensitive.

Table 1: Effects on soil microorganisms

	Control [mg CO2 /h/kg dry wt soil]	0.07 mg/kg a.s.  [mg CO2 /h/kg dry wt soil]	difference to control	0.72 mg/kg a.s.  [mg CO2 /h/kg dry wt soil]	difference to control
0 days	258.3 ± 4.1	246.6 ± 6.6	5%	244.1 ± 5.2	5%
7 days	271.9 ± 18.8	256.1 ± 14.2	6%	256.6 ± 5.8	6%
14 days	267.8 ± 10.2	247.7 ± 4.3	8%	246.0 ± 4.5	8%
28 days	219.0 ± 7.4	198.6 ± 8.4	9%	199.5 ± 3.2	9%

Description of key information

 The substance caused no effects on soil microorganisms above the trigger value of 25% deviation from the control.

Additional information

The potential effects of triafamone (CAS No. 874195-61-6) on nitrogen and carbon transformation of terrestrial microorganisms was investigated with soil from an uncultivated site (Frommholz, 2010). The studies were performed according to OECD guideline 216 and 217 under GLP conditions. In the test on nitrogen transformation triafamone caused a temporary stimulation at the time interval 0-7 days after treatment. At the end of the test (14-28 day interval), differences between control soil samples and treated soil samples were below the trigger value of 25% deviation.Also the carbon dioxide production does not exceed the trigger value of 25% after an exposure of 28 days, even though a statistically significant difference to the control at the end of the test occurred. Hence it can be concluded that triafamone have a very temporary and slight impact on soil microorganisms.