3-iodo-2-propynyl butylcarbamate

Toxicity to terrestrial plants

Link to relevant study record(s)

Reference

Endpoint:

toxicity to terrestrial plants: long-term

Type of information:

experimental study

Adequacy of study:

key study

Study period:

from 2003-12-17 to 2004-05-24

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)

Version / remarks:

Proposal for Updating Guideline 208, Draft Document July 2000

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

- Batch No.: 0306-8715A

Analytical monitoring:

yes

Details on sampling:

- Sampling method: Two aliquots (soil samples of 200 g each) of the highest and lowest test rate were taken immediately after mixing the treated sand into the soil. Four aliquots (200 g/aliquot) of the solvent control were prepared the day after application using the same materials and conditions.
- Sample storage conditions before analysis: kept deep frozen for a possible later analysis

Vehicle:

yes

Remarks:

Acetone

Details on preparation and application of test substrate:

- Method of mixing into soil: small amounts of the test item were dissolved in 10 mL of acetone (99.8 %) and mixed with fine quartz sand under a fume hood until the solvent is evaporated and then mixed into soil using a laboratory mixer for approximately 10 minutes. Equal amounts of sand (1.58 % of soil fresh weight) and solvent (10 mL acetone) were added to all treatment groups.
- Controls: The untreated control soil was mixed with the same amount of untreated sand as the treatment groups.
- Solvent control: The solvent control soil was mixed with the same amount of acetone treated sand as the treatment groups.
- Chemical name of vehicle: Acetone
- Concentration of vehicle in test medium: 10 mL acetone per treatment group
- Evaporation of vehicle before use: yes

Species:

Avena sativa

Plant group:

Monocotyledonae (monocots)

Details on test organisms:

- Common name: Oat
- Plant family: Poaceae
- Variety: Freddy
- Source of seed: Saatenunion, Hannover, Germany
- Prior seed treatment/sterilization: untreated

Species:

Glycine max (G. soja)

Plant group:

Dicotyledonae (dicots)

Details on test organisms:

- Common name: Soybean
- Plant family: Fabaceae
- Source of seed: Syringa, Hilzingen-Binningen, Germany
- Prior seed treatment/sterilization: untreated

Species:

Brassica napus

Plant group:

Dicotyledonae (dicots)

Details on test organisms:

- Common name: Oilseed rape
- Plant family: Brassicaceae
- Variety: Spirit
- Source of seed: Syngenta Seeds, Bad Salzuflen, Germany
- Prior seed treatment/sterilization: untreated

Test type:

seedling emergence and seedling growth test

Study type:

laboratory study

Substrate type:

natural soil

Limit test:

no

Total exposure duration:

26 d

Test temperature:

day: 24 °C
night: 18 °C

pH:

6.3 ± 0.4

Moisture:

day: 55 %
night: 60 %

Details on test conditions:

TEST SYSTEM
- Testing facility: Institut für Biologische Analytik und Consulting IBACON GmbH
- Test container: Commercial plastic pots, diameter 12 cm and 14 cm
- Amount of soil: 30 kg for concentrationa 3.23 to 50.4 mg/kg dry soil, 22 kg for 126 mg/kg dry soil, 10 kg for 1.29 mg/kg dry soil; acetone control and untreated control - 30 kg soil
- Method of seeding: manual sowing
- No. of seeds per container: 5
- No. of replicates per treatment group: 8
40 seeds per species and treatment group were tested.

SOURCE AND PROPERTIES OF SUBSTRATE
- The soil was analysed before the test:
Lufa 2.3 (sandy loam; USDA)
all particles smaller than 0.2 cm
1.02 + 0.17 % organic carbon
pH 6.3 ± 0.4

GROWTH CONDITIONS
- Photoperiod: 16 hours light / 8 hours dark
- Light intensity and quality: 5090 to 16500 Lux
- Day/night temperatures: 24 / 18 °C
- Relative humidity (%): 55 - 60
- Interval of applications: after daily spot check
- Method of application: bottom watering through saucers
- Any fertilization: Flory 9 (Euflor) 1 g/L with Sequestren (Ciba-Geigy) 0.05 g/L was given after development of the first true leaves. Fertilizer was given one to three times a week depending on the development of the plants.

VEHICLE CONTROL PERFORMED: yes

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 2.5
- Test concentrations: 125, 50, 20, 8, 3.2, 1.28 mg a.i./kg soil dry weight.

Nominal and measured concentrations:

Nominal concentrations: Control, Solvent Control, 125, 50, 20, 8, 3.2, 1.28 mg a.i./kg soil dry weight.

Reference substance (positive control):

no

Key result

Species:

Avena sativa

Duration:

21 d

Dose descriptor:

EC50

Effect conc.:

4.92 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: fresh weight

Species:

Avena sativa

Duration:

21 d

Dose descriptor:

EC25

Effect conc.:

3.11 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: fresh weight

Species:

Avena sativa

Duration:

21 d

Dose descriptor:

LOEC

Effect conc.:

1.28 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: fresh weight

Key result

Species:

Avena sativa

Duration:

21 d

Dose descriptor:

NOEC

Effect conc.:

< 1.28 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: fresh weight

Key result

Species:

Glycine max (G. soja)

Duration:

21 d

Dose descriptor:

EC50

Effect conc.:

6.89 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: fresh weight

Species:

Glycine max (G. soja)

Duration:

21 d

Dose descriptor:

EC25

Effect conc.:

1.64 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: fresh weight

Species:

Glycine max (G. soja)

Duration:

21 d

Dose descriptor:

LOEC

Effect conc.:

8 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: fresh weight

Key result

Species:

Glycine max (G. soja)

Duration:

21 d

Dose descriptor:

NOEC

Effect conc.:

3.2 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: fresh weight

Key result

Species:

Brassica napus

Duration:

21 d

Dose descriptor:

EC50

Effect conc.:

12.12 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: fresh weight

Species:

Brassica napus

Duration:

21 d

Dose descriptor:

EC25

Effect conc.:

6.18 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: fresh weight

Species:

Brassica napus

Duration:

21 d

Dose descriptor:

LOEC

Effect conc.:

3.2 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: fresh weight

Key result

Species:

Brassica napus

Duration:

21 d

Dose descriptor:

NOEC

Effect conc.:

< 3.2 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: fresh weight

Details on results:

Fresh weight, germination and mortality of the plants treated with the test item were compared to those of the control plants.

Reported statistics and error estimates:

In order to determine the EC25 and EC50 values, a regression analysis (Probit-analysis) was performed. For the gemiination and mortality data Fischer Exact Test was used.

Avena sativa:

Fresh weight was reduced at all tested rates (9 to 99 %). Both control types were not significantly different. The growth stages indicate that at 20 mg a.i./kg soil dry weight and above the growth of the plants was reduced. The germination rate was 98 and 90 % in the acetone and the untreated control, respectively. The germination rate (21 DAG) ranged between 90 and 98 % in the treatment groups. Mortality was not observed 14 days after 50 % germination in the control (DAG). 21 DAG mortality was observed at 50 mg a.i./kg soil dry weight (5 %). Phytotoxic effects (21 DAG), chlorosis and growth depression, was observed at 8 mg a.i./kg soil dry weight and above (5 to 70 %).

Glycine max:

The untreated control and the acetone control were not statistically significant different, therefore they were pooled. Fresh weight was significantly reduced compared to the pooled control at 8 mg a.i./kg soil dry weight and above (52 to 89 %). There growth stages indicate that at 20 mg a.i./kg soil dry weight and above plant growth was reduced. The germination rate (21 DAG) was 80 and 78 % in the acetone and the untreated control, respectively. The germination rate ranged between 73 and 93 % in the treatment groups. Mortality was not observed 14 DAG. 21 DAG mortality was observed at 125 mg a.i./kg soil dry weight (19 %). Phytotoxic effects were chlorosis, necrosis and growth depression. Phytotoxicity (21 DAG) was observed at 8 mg a.i./kg soil dry weight and above (50 to 92 %).

Brassica napus:

The untreated control showed a fresh weight 6 % lower than the control with acetone. Therefore the statistical analysis were performed comparing the treatment groups with the acetone control, only. Fresh weight was statistically significantly reduced at all tested concentrations (19 to 100 %). The growth stages indicate that at 50 mg a.i./kg soil dry weight and above growth stages were reduced. The germination rate (21 DAG) was 98 and 95 % in the acetone and the untreated control, respectively. The germination rate ranged between 90 and 100 % in the treatment groups. Mortality was not observed 14 DAG. 21 DAG mortality was observed at 50 and 125 mg a.i./kg soil dry weight (15 and 19 %, respectively). Phytotoxic effects were chlorosis, necrosis and growth depression. Phytotoxicity was observed at 8 mg a.i./kg soil dry weight and above (1 to 87 %).

Validity criteria fulfilled:

yes

Conclusions:

The EC50 and NOEC for the 3 tested species were determined with the Probit analysis using the fresh weight.
Alena sativa:
EC50 = 4.92 mg a.i./kg soil
NOEC = <1.28 mg a.i./kg soil
Glycine max:
EC50 = 6.89 mg a.i./kg soil
NOEC = 3.20 mg a.i./kg soil
Brassica napus:
EC50 = 12.12 mg a.i./kg soil
NOEC = <3.2 mg a.i./kg soil

Executive summary:

The test substance was tested for effects on the seedling emergence and seedling growth of 3 species out of 3 different plant families followint the Draft Proposal on OECD Guideline 208 (2000). The most sensitive species was Avena sativa with an EC50 of 4.92 mg a.i./kg soil dry weight followed by Glycine max and Brassica napus with EC50 values of 6.89 and 12.12 mg a.i./kg soil dry weight, respectively. The EC50 values were calculated based on fresh weight using Probit analysis.

The test item caused no effect on the germination of the tested species in this study. Mortality was observed at 50 mg a.i./kg soil dry weight for Avena sativa (5 %, not statistically significant) and at 50 and 125 mg a.i./kg soil dry weight for Brassica napus (15 and 19 %, statistically significant). For Glycine max mortality occurred at 125 mg a.i./kg soil dry weight (19 %, statistically significant).

Phytotoxic symptoms were chlorosis, necrosis and growth reduction. 21 days after at least 50 % germination of the control, symptoms were observed at 8 mg a.i./kg and higher concentrations.

Description of key information

In an OECD 208 equivalent study the following results were obtained:

Alena sativa:

EC50 = 4.92 mg a.i./kg soil

NOEC = <1.28 mg a.i./kg soil

Glycine max:

EC50 = 6.89 mg a.i./kg soil

NOEC = 3.20 mg a.i./kg soil

Brassica napus:

EC50 = 12.12 mg a.i./kg soil

NOEC = <3.2 mg a.i./kg soil

Key value for chemical safety assessment

Short-term EC50 or LC50 for terrestrial plants:

4.92 mg/kg soil dw

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

1.28 mg/kg soil dw

Additional information

The test substance was tested for effects on the seedling emergence and seedling growth of 3 species out of 3 different plant families following the Draft Proposal on OECD Guideline 208 (2000). The most sensitive species was Avena sativa with an EC50 of 4.92 mg a.i./kg soil dry weight followed by Glycine max and Brassica napus with EC50 values of 6.89 and 12.12 mg a.i./kg soil dry weight, respectively. The EC50 values were calculated based on fresh weight using Probit analysis.

The test item caused no effect on the germination of the tested species in this study. Mortality was observed at 50 mg a.i./kg soil dry weight for Avena sativa (5 %, not statistically significant) and at 50 and 125 mg a.i./kg soil dry weight for Brassica napus (15 and 19 %, statistically significant). For Glycine max mortality occurred at 125 mg a.i./kg soil dry weight (19 %, statistically significant).

Phytotoxic symptoms were chlorosis, necrosis and growth reduction. 21 days after at least 50 % germination of the control, symptoms were observed at 8 mg a.i./kg and higher concentrations.