Reaction mass of potassium trifluoroacetate and potassium trifluoromethanesulphinate

Toxicity to terrestrial plants

Link to relevant study record(s)

Reference

Endpoint:

toxicity to terrestrial plants: short-term

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From 2017-05-05 to 2018-12-28

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 208 (Terrestrial Plants Test: Seedling Emergence and Seedling Growth Test)

Deviations:

no

Qualifier:

according to guideline

Guideline:

other: Ministry of environmental protection of the people's Republic of China, The Guidelines for the Testing of Chemicals - Effects on Biotic Systems, 2013, 208 Terrestrial Plants, Growth Test

GLP compliance:

yes (incl. QA statement)

Remarks:

Certificate from 25 September 2017

Analytical monitoring:

no

Vehicle:

yes

Remarks:

Deionized water

Details on preparation and application of test substrate:

- Method of mixing into soil (if used): A stock solution was prepared by dissolving 49.997 g of the Reaction mass of TFSK/TFAK (dry powder) and dissolved in 5 L deionized water resulting in a 10 g/L stock solution. The pH of the stock solution was 3.56 and adjusted to 6.90 by HCl and NOH. Adequate volumes of the stock solution were mixed with deionized water to reach sample solutions with different concentrations. Then the sample solutions were incorporated into formulated artificial soil and fully mixed to give the different treatment groups. The proportion of the volume of test substance solution and the dry weight of artificial soil was the same in all groups.
- Controls: Blank controls were maintained under identical conditions but not exposed to the test substance.

Species:

Glycine max (G. soja)

Plant group:

Dicotyledonae (dicots)

Details on test organisms:

- Common name: Soybean
- Source of seed: Untreated seeds were obtained from a local commercial supplier (Shanghai Keyuan seed co. LTD) on Mar 6th 2017.
- Seed storage: Seeds were preserved under the humidity of 30 ± 10% and at a temperature of 5 ± 1 °C.
- Prior seed treatment: Before the study started, the seeds were screened and damaged seeds were discarded. The seeds with the same level of size and weight were selected.

Species:

Zea mays

Plant group:

Monocotyledonae (monocots)

Details on test organisms:

- Common name: Corn
- Source of seed: Untreated seeds were obtained from a local commercial supplier (Shanghai Keyuan seed co. LTD) on Mar 6th 2017.
- Seed storage: Seeds were preserved under the humidity of 30 ± 10% and at a temperature of 5 ± 1 °C.
- Prior seed treatment: Before the study started, the seeds were screened and damaged seeds were discarded. The seeds with the same level of size and weight were selected.

Species:

Cucumis sativus

Plant group:

Dicotyledonae (dicots)

Details on test organisms:

- Common name: Cucumber
- Source of seed: Untreated seeds were obtained from a local commercial supplier (Shanghai Keyuan seed co. LTD) on Mar 6th 2017.
- Seed storage: Seeds were preserved under the humidity of 30 ± 10% and at a temperature of 5 ± 1 °C.
- Prior seed treatment: Before the study started, the seeds were screened and damaged seeds were discarded. The seeds with the same level of size and weight were selected.

Species:

Oryza sativa

Plant group:

Monocotyledonae (monocots)

Details on test organisms:

- Common name: Rice
- Source of seed: Untreated seeds were obtained from a local commercial supplier (Shanghai Keyuan seed co. LTD) on Mar 6th 2017.
- Seed storage: Seeds were preserved under the humidity of 30 ± 10% and at a temperature of 5 ± 1 °C.
- Prior seed treatment: Before the study started, the seeds were screened and damaged seeds were discarded. The seeds with the same level of size and weight were selected.

Test type:

seedling emergence and seedling growth test

Study type:

laboratory study

Substrate type:

artificial soil

Limit test:

no

Total exposure duration:

14 d

Remarks:

The test was ended after the emergence rate reached 50% in the control group.

Test temperature:

20.1 - 23.6°C

Moisture:

Relative humidity: 57.1 - 76.3

Details on test conditions:

TEST SYSTEM
- Test container (type, material, size): plastic flowerpots of 12 cm diameter, with holes in the bottom. 4 pots were randomly were placed in a tray (25 cm x 50 cm) and placed in a climate box.
- No. of seeds per container (= replicate): 2
- No. of replicates per treatment group: 10 (20 seeds per treatment group)
- No. of replicates per control: 10 (20 seeds per control)

SOURCE AND PROPERTIES OF SUBSTRATE
- Geographic location: Not applicable, artificial soil
- Soil texture: A defined artificial soil was used as test substrate with the following composition: 20% Kaolin clay, 75% quartz sand, 5% peat. The pH of the soil was 6.05 and the total organ carbon was 21.12 g/kg.

TEST WATER:
- Description: purified water (milli-Q ultrapure water mechanism)

GROWTH CONDITIONS
- Photoperiod: 20 hours illumination per day
- Light intensity and quality: 22.4 - 26.9 klux
- Temperatures: 22 ± 10°C (setpoint)
- Relative humidity (%): 70 ± 25% (setpoint)
- Watering: To assure good plant growth as judged by the control plants of the selected species. Bottom watering of test containers was applied.

EFFECT PARAMETERS MEASURED: During the test the emergence/growth of the seeds, temperature and humidity were recorded daily. At the end of the test, fresh weight and the stem height were measured for each replicate. For each species, mean values and standard deviation of seedling emergence, fresh weight and stem height in treatment and control groups were calculated. EC10, EC25 and EC50 values of seedling emergence, fresh weight and stem height were calculated and significant difference compared with the control group and treatment group was determined. The data were analyzed using the software TOXCALC v5.0.32.

TEST CONCENTRATIONS
- Range finding study: Yes
- Test concentrations: 1, 10, 100, 500 and 10000 mg/kg and a control group were included in the range finding test. Ten seeds were exposed to each group, divided into five replicates of 2 seeds each.
- Results used to determine the conditions for the definitive study: Yes

Nominal and measured concentrations:

Nominal concentrations:
♦ Soybean and cucumber: 9.8, 24.8, 62.5, 157.5, 396.8 and 1000 mg/kg
♦ Rice: 9.8, 19.5, 38.6, 76.5, 151.5 and 300 mg/kg
♦ Corn: 9.8, 19.5, 38.6, 76.5, 151.5, 300 and 1000 mg/kg
Controls were tested in parallel.

Reference substance (positive control):

no

Species:

Glycine max (G. soja)

Duration:

14 d

Dose descriptor:

NOEC

Effect conc.:

>= 1 000 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

seedling emergence

Species:

Zea mays

Duration:

14 d

Dose descriptor:

NOEC

Effect conc.:

>= 1 000 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

seedling emergence

Species:

Cucumis sativus

Duration:

14 d

Dose descriptor:

NOEC

Effect conc.:

>= 1 000 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

seedling emergence

Species:

Oryza sativa

Duration:

14 d

Dose descriptor:

EC10

Effect conc.:

31 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

seedling emergence

Remarks on result:

other: 95% CL: 20.7-43.1 mg/kg

Species:

Oryza sativa

Duration:

14 d

Dose descriptor:

EC50

Effect conc.:

57 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

seedling emergence

Remarks on result:

other: 95% CL: 46.0-61.9 mg/kg

Details on results:

RESULTS (See Table 1 'any other information on results')

SOYBEAN (Glycine max)
♦ There was no significant difference in the rate of emergence and stem height between the treatment groups and the control group, the NOEC was ≥1000 mg/kg, the EC50 was >1000 mg/kg.
♦ The fresh weight was significantly inhibited, the NOEC was 9.8 mg/kg, the LOEC was 24.8 mg/kg, and the EC50 value was >1000 mg/kg.
♦ Survival rate: At exposure concentrations higher than 24.8 mg/kg, the soybean plant led to abnormal growth (percent injury >80%), but the survival rate was almost 100%.

CORN (Zea mays)
♦ Seedling emergence: There was no significant difference in the rate of emergence between the treatment groups and the control group, the NOEC was ≥1000 mg/kg, the LOEC and EC50 were >1000 mg/kg.
♦ Stem height: the stem height was significantly inhibited by the test substance:
- NOEC was 9.8 mg/kg, the LOEC was 19.5 mg/kg,
- EC10 was 11.5 mg/kg (95% confidence limit: 6.55-15.5 mg/kg)
- EC25 was 18.5 mg/kg (95% confidence limit: 13.0-22.9 mg/kg)
- EC50 was 31.4 mg/kg (95% confidence limit: 25.8-38.2 mg/kg)
♦ For fresh weight the following effect concentrations were calculated:
- EC10 was 8.52 mg/kg (95% confidence limit: 2.51-15.4 mg/kg)
- EC25 was 20.6 mg/kg (95% confidence limit: 9.90-30.9 mg/kg)
- EC50 was 55.1 mg/kg (95% confidence limit: 38.1-80.0 mg/kg)
♦ Survival rate: At exposure concentrations higher than 19.5 mg/kg, the corn plant led to abnormal growth (percent injury >80%), but the survival rate was >74%

CUCUMBER (Cucumis sativus)
- For seedling emergence, the NOEC ≥1000 mg/kg, the LOEC and EC50 were >1000 mg/kg.
- For stem height the EC50 was >1000 mg/kg
- For fresh weight the following effect concentrations were calculated:
♦ EC10 was 14.9 mg/kg (95% confidence limit: 3.22-31.8 mg/kg)
♦ EC25 was 78.8 mg/kg (95% confidence limit: 39.2-122 mg/kg)
♦ EC50 was 418 mg/kg (95% confidence limit: 271-826 mg/kg)
- Survival rate: At exposure concentrations higher than 24.8 mg/kg, the survival rate of the cucumber plant began to reduce and reached 45% at the exposure concentration of 1000 mg/kg.

RICE (Oryza sativa)
- For seedling emergence, the following effect concentrations were calculated:
♦ EC10 was 31.0 mg/kg (95% confidence limit: 20.7-43.1 mg/kg)
♦ EC25 was 43.2 mg/kg (95% confidence limit: 30.4-50.0 mg/kg)
♦ EC50 was 50.7 mg/kg (95% confidence limit: 46.0-61.9 mg/kg)
- Stem height: NOEC <9.8 mg/kg. At exposure concentrations >19.5 mg/kg, all of the plants died before the end of the experiment. Those test concentration groups could not be used to calculate the effect of stem height. Only two concentrations were left so that the regression curve could not be plotted. At the lowest concentration of the treatment group (i.e. 9.8 mg/kg), the stem height was significantly affected (21%) compared with the control group. At the treatment group of 19.5 mg/kg, the effect reached 81%.
- Fresh weight: NOEC of 9.8 mg/kg, LOEC 19.5 mg/kg. The effect at 19.5 mg/kg reached 80%, while the treated group of 9.8 mg/kg did not show any obvious effect.

Table 1 - Summary of effects of test item on 4 plant species in seedling emergence tests after 14 days of exposure

Species	Endpoint	NOEC (mg/kg)	LOEC (mg/kg)	EC10 (mg/kg)	95% C.I. (mg/kg)	EC25 (mg/kg)	95% C.I. (mg/kg)	EC50	95% C.I.
Soybean	Emergence Stem height Fresh weight	≥ 1000 ≥ 1000 9.8	>1000 >1000 24.8	>1000 >1000 n.a.	n.a. n.a. n.a.	>1000 >1000 n.a.	n.a. n.a. n.a.	>1000 >1000 >1000	n.a. n.a. n.a.
Corn	Emergence Stem height Fresh weight	≥ 1000 9.8 n.a.	>1000 19.5 n.a.	n.a. 11.5 8.52	n.a. 6.55 – 15.5 2.51 – 15.4	n.a. 18.5 20.6	n.a. 13.0 – 22.9 9.90 – 30.9	>1000 31.4 55.1	n.a. 25.8 – 38.2 38.1 – 80.0
Cucumber	Emergence Stem height Fresh weight	≥ 1000 n.a. n.a.	>1000 n.a. n.a.	n.a. n.a. 14.9	n.a. n.a. 3.22 – 31.8	n.a. n.a. 78.8	n.a. n.a. 39.2 – 122	>1000 >1000 418	n.a. n.a. 271 – 826
Rice	Emergence Stem height Fresh weight	n.a. < 9.8 9.8	n.a. n.a. 19.5	31.0 n.a. n.a.	20.7 – 43.1 n.a. n.a.	43.2 n.a. n.a.	30.4 – 50.0 n.a. n.a.	57.0 n.a. n.a.	46.0 – 61.9 n.a. n.a.

n.a. : Not applicable due to no clear concentration-effect relationship or scattering of data

95% C.I. : 95% Confidence intervals

Validity criteria fulfilled:

yes

Conclusions:

For soybean, corn and cucumber the test substance had no effect on the emergence rate up to 1000 mg/kg d.s. For rice the EC10 for emergence rate was 31 mg/kg d.s. The lowest EC10 for stemheight and freshweight were 11.5 and 8.52 mg/kg, respectively for corn. Under the conditions of the test, the lowest 14 -Day EC50 was 31.4 mg/kg d.s. (corn).

Executive summary:

The effects of the Reaction mass of potassium trifluoroacetate and potassium trifluoromethanesulphinate on the seedling emergence was assessed in a GLP compliant study according to OECD 208. Soybean (Glycine max), Corn (Zea mays), Cucumber (Cucumis sativus and Rice (Oryza sativa) were slected as the test plant species for the test. The test item was mixed into the artificial soil directly before the seeds of the plants species were sown. The nominal concentrations of the treatment groups ranged between 9.8 and 1000 mg/kg dry artificial soil weight for soybean, corn and cucumber and between 9.8 and 3000 mg/kg dry weight for rice. A control group, maintained under identical conditions was included. At 14 days after the seedling emergence reached 50% in the control group, stem height and fresh weights of the testing plants were measured.

In the control groups, the seedling emergence were above 70% (i.e. 100% for soybean, 90% for corn, 75% for cucumber and 85% for rice), the survival rate during the study was above 90% (i.e. 100% for all tested species) and seedlings did not exhibit visible phytotoxic effects (such as chlorosis, necrosis, wilting, leaf and stem deformation) and therefore the test was considered valid.

The test results show the following effect concentrations:

- Soybean: For emergence rate and stem height, the NOEC was ≥ 1000 mg/kg d.s., the LOEC and EC50 were higher than 1000 mg/kg. For fresh weight, the NOEC was 9.8 mg/kg d.s., the LOEC 24.8 mg/kg and the EC50 was >1000 mg/kg.

- Corn: For emergence rate, the NOEC was≥1000 mg/kg d.s., the LOEC and EC50 were higher than 1000 mg/kg d.s. For stem height the NOEC was 9.8 mg/kg d.s. and the EC50 was 31.4 mg/kg d.s. For fresh weight the EC10 was 8.52 mg/kg d.s. and the EC50 was 55.1 mg/kg d.s.

- Cucumber: For emergence rate, the NOEC was≥1000 mg/kg d.s., the LOEC and EC50 were higher than 1000 mg/kg d.s. For stem height the EC50 was >1000 mg/kg d.s.; for fresh weight the EC10 was 14.9 mg/kg d.s. and the EC50 was 418 mg/kg d.s.

- Rice: For emergence rate, the EC10 was 31.0 mg/kg d.s. and the EC50 was 57.0 mg/kg d.s. For stem height, the NOEC was < 9.8 mg/kg. For fresh weight the NOEC was 9.8 mg/kg.

Description of key information

The acute toxicity of the test item to terrestrial plantswas investigated in a GLP-compliant study performedin accordance with OECD 208. The study is considered as reliable (Klimisch 1) and is considered as a key study for the endpoint.

Key value for chemical safety assessment

Short-term EC50 or LC50 for terrestrial plants:

31.4 mg/kg soil dw

Long-term EC10, LC10 or NOEC for terrestrial plants:

8.52 mg/kg soil dw

Additional information

The toxicity of the test item on the emergence and growth of terrestrial plantswas investigated in a GLP-compliant study performed in accordance withOECD Guideline No. 208. In the study four plant species were investigated:Glycine max(soybean),Zea mays(corn),Cucumis sativus(cucumber) andOryza sativa(rice).For soybean, corn and cucumber the test substance had no effect on the emergence rate up to 1000 mg/kg d.s. The lowest EC10 for emergence rate was 31 mg/kg d.s. for rice. The lowest EC10 for stemheight and freshweight were 11.5 and 8.52 mg/kg, respectively for corn. Under the conditions of the test, the lowest 14 -Day EC50 was 31.4 mg/kg d.s. (corn).