Ethyl [2-(4-phenoxyphenoxy)ethyl]carbamate

Toxicity to terrestrial plants

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

toxicity to terrestrial plants: short-term

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

comparable to guideline study

Qualifier:

equivalent or similar to guideline

Guideline:

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

Deviations:

yes

Remarks:

See Guidelines and limitations in 'Any other information on materials and methods incl. tables'

Principles of method if other than guideline:

Three monocot and three dicot crops were exposed to the test substance up to 1800 g/ha. Seedling emergence and vegetative vigour of the plants were assessed after 21 and 16 days, respectively.

GLP compliance:

no

Analytical monitoring:

no

Vehicle:

no

Species:

Allium cepa

Plant group:

Monocotyledonae (monocots)

Species:

Glycine max (G. soja)

Plant group:

Dicotyledonae (dicots)

Species:

other: Avena fatua

Plant group:

Monocotyledonae (monocots)

Species:

Brassica napus

Plant group:

Dicotyledonae (dicots)

Species:

Zea mays

Plant group:

Monocotyledonae (monocots)

Species:

Beta vulgaris

Plant group:

Dicotyledonae (dicots)

Test type:

seedling emergence toxicity / vegetative vigour test

Study type:

laboratory study

Substrate type:

artificial soil

Limit test:

no

Total exposure duration:

21 d

Remarks:

Seedling emergence: 21 days; Vegetative vigour: 16 days

Reference substance (positive control):

no

Species:

Brassica napus

Duration:

16 d

Dose descriptor:

other: NOER

Effect conc.:

450 g/ha

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

formulation

Basis for effect:

phytotoxicity

Remarks:

Vegetative vigour test

Remarks on result:

other:

Remarks:

equivalent to 112.5 g/ha

An overview of the results is provided in Table 1 - Table 3 below.

Results

It was reported that more than 90% of the control seeds produced healthy seedlings, and that control seedlings exhibited normal growth throughout the test.

- Seedling emergence: On B. napus, A. fama, B. vulgaris, Z. mays, G. max, and A. cepa no effect of the test item could be detected in any of the treatments, i.e 1800, 900, 450, 250, 112.5, and 56.25 g/ha. 

- Vegetative vigour: On B. napus a mean visual effect rating of 6 was observed in the 1800 g/ha and of 8 in the 900 g/ha. No effect of the test item could be detected in any of the other treatments, i.e. 450, 250, 112.5, and 56.25 g/ha.

On A. fatua, B. vulgaris, Z. mays, G. max, and A. cepa no effect of the test item could be detected in any of the treatments, i.e 1800, 900, 450, 250, 112.5, and 56.25 g/ha.

Table 1.The phytotoxic effects of the test substance on seedling emergence of six plant species

	Phytotoxic rating(A) at application rate (g product/ha):
	56.25	112.5	225	450	900	1800
Maize (Zea mays)	9	9	9	9	9	9
Wild oat (Avena fatua)	9	9	9	9	9	9
Onion (Allium cepa)	9	9	9	9	9	9
Sugar beet (Beta vulgaris)	9	9	9	9	9	9
Oilseed rape (Brassica napus)	9	9	9	9	9	9
Soybean (Glycine max)	9	9	9	9	9	9

(A) Mean of two replicates; rating scale of 0 to 9 (comparison to controls), where 1 represented complete destruction or no emergence, and 9 no effect, similar to untreated

 

Table 2.The phytotoxic effects of the test substance on vegetative vigor of six plant species

	Phytotoxic rating(A) at application rate (g product/ha):
	56.25	112.5	225	450	900	1800
Maize (Zea mays)	9	9	9	9	9	9
Wild oat (Avena fatua)	9	9	9	9	9	9
Onion (Allium cepa)	9	9	9	9	9	9
Sugar beet (Beta vulgaris)	9	9	9	9	9	9
Oilseed rape (Brassica napus)	9	9	9	9	8	6
Soybean (Glycine max)	9	9	9	9	9	9

(A) Mean of two replicates; rating scale of 0 to 9 (comparison to controls), where 1 represented complete destruction or no emergence, and 9 no effect, similar to untreate

Table 3. Phtyotoxicity assessment categories used at the time of generation of non-target plant screening data

Score	9	8	7	6	5	4	3	2	1
% damage	0	12.5	25	37.5	50	62.5	75	87.5	100

 

Validity criteria fulfilled:

yes

Remarks:

See guidelines and limitations in 'Any other information on materials and methods incl. tables'

Conclusions:

Based on a seedling emergence and vegetative vigour study, without following guidelines, but well documented and meets generally accepted scientific principles, the 16-d NOER for vegetative vigour was established to be 450 g product/ha (equivalent to 112.5 g test substance /ha).

Executive summary:

In a greenhouse screening study, the formulation of the test substance was applied to three monocot and three dicot crops at doses of 56.25, 112.5, 225, 450, 900 and 1800 g/ha and a negative (water) control. The study was performed without following guideline and not in compliance with GLP. However, the study was well documented and meets generally accepted scientific principles. Thus, it is considered acceptable for assessment. Applications were made in 500 L of water per ha either pre-emergence (application to the soil surface within 24 hours from planting the seeds) or postemergence (applications to the plant canopy 14 - 17 days after emergence) of target plants using a laboratory sprayer. Each treatment was tested in 2 replicates containing 3 (maize and soybean), 5 (sugar beet) 6 (wild oat) or 20 (oilseed rape and onion) seeds or plants per tray. Visual phytotoxicity ratings were recorded 16 and 21 days after the application of the test item for vegetative vigour and seedling emergence, respectively. Test conditions were as following: 18 - 27°C (maize and soybean) or 15 - 22°C (wild oat, onion, sugar beet and oilseed rape), relative humidity 40 - 60%, light >10000 lux (14-hour light period). Soil characteristics: clay loam ( 26% clay, 34% silt and 40% sand, 2.6% oc, pH 7.5). Evaluation of phytotoxicity was by visual observations that used a rating scale ranging from 1 (complete destruction or no emergence of the plants) to 9 (no effect, similar to untreated). Individual scoring was always as compared to the untreated control.

No effect of the test item could be detected in any of the treatments in the seedling emergence test. In the vegetative vigour test, a mean visual effect rating of 6 on oilseed rape was observed in the1800 g product /ha and of 8 in the 900 g product /ha. No effect of the test item could be detected in any of the other treatments. Based on the findings,the 16 -d NOER for vegetative vigour was established to be 450 g product /ha (equivalent to 112.5 g test substance/ha).

Reference 2

Endpoint:

toxicity to terrestrial plants: short-term

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

comparable to guideline study

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 227 (Terrestrial Plant Test: Vegetative Vigour Test)

Deviations:

yes

Remarks:

See Guidelines and limitations in 'Any other information on materials and methods incl. tables'

GLP compliance:

no

Analytical monitoring:

no

Vehicle:

no

Species:

Glycine max (G. soja)

Plant group:

Dicotyledonae (dicots)

Species:

Brassica napus

Plant group:

Dicotyledonae (dicots)

Species:

Beta vulgaris

Plant group:

Dicotyledonae (dicots)

Species:

Allium cepa

Plant group:

Monocotyledonae (monocots)

Species:

other: Avena fatua

Plant group:

Monocotyledonae (monocots)

Species:

Zea mays

Plant group:

Monocotyledonae (monocots)

Test type:

seedling emergence toxicity / vegetative vigour test

Study type:

laboratory study

Substrate type:

artificial soil

Limit test:

no

Total exposure duration:

21 d

Remarks:

Seedling emergence: 21 days; Vegetative vigour: 14 days

Species:

Zea mays

Duration:

14 d

Dose descriptor:

other: NOER

Effect conc.:

37.5 g/ha

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

formulation

Basis for effect:

phytotoxicity

Remarks on result:

other:

Remarks:

equivalent to 9.38 g/ha test substance

Species:

Allium cepa

Duration:

21 d

Dose descriptor:

other: NOER

Effect conc.:

300 g/ha

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

formulation

Basis for effect:

seedling emergence

Remarks on result:

other:

Remarks:

equivalent to 75 g/ha test substance

An overview of the results is provided in Table 1 - Table 3 below.

Results

It was reported that more than 90% of the control seeds produced healthy seedlings, and that control seedlings exhibited normal growth throughout the test.

- Seedling emergence: On A. cepa a mean visual effect rating of 6.5 was observed in the 600 g/ha test substance formulation. No effect of the test item could be detected in any of the other treatments, i.e. 300, 150, 75, 37.5 and 18.75 g/ha. On B. napus, A. fatua, B. vulgaris, Z mays and G. max no effect of the test item could be detected in any of the treatment levels.

- Vegetative vigour: On A. cepa a mean effect rating of 7 was observed in the 600 g/ha of 8 in the 300 g/ha and 8.5 in the 150 g/ha treatment level. No effect of the test item could be detected in of the other treatment levels i.e. 75, 37.5 and 18.75 g/ha. On G. max a mean visual effect rating of 8 was observed in the 600, 300 and the 150 g/ha treatment levels. No effect of the test item could be detected in any of the other treatments levels i. .e. 75, 37.5 and 18.75 g/ha. On Z. mays a mean visual effect rating of 8.5 was observed in the 600, 300, 150 and the 75 g/ha treatment levels. No effect of the test item could be detected in the 37.5 and the 18.75 g/ha treatment levels. The treatment had no effect on B. napus, A. fatua and B. vulgaris at any of the treatment levels.

 

Table 1.The phytotoxic effects of the test substance on seedling emergence of six plant species

	Phytotoxic rating (A) at application rate (g product/ha):
	18.75	37.5	75	150	300	600
Maize (Zea mays)	9	9	9	9	9	9
Wild oat (Avena fatua)	9	9	9	9	9	9
Onion (Allium cepa)	9	9	9	9	9	6.5
Sugar beet (Beta vulgaris)	9	9	9	9	9	9
Oilseed rape (Brassica napus)	9	9	9	9	9	9
Soybean (Glycine max)	9	9	9	9	9	9

(A) Mean of two replicates; rating scale of 0 to 9 (comparison to controls), where 1 represented complete destruction or no emergence, and 9 no effect, similar to untreated

Table 2.The phytotoxic effects of the test substance on vegetative vigor of six plant species

	Phytotoxic rating (A) at application rate (g product/ha):
	18.75	37.5	75	150	300	600
Maize (Zea mays)	9	9	8.5	8.5	8.5	8.5
Wild oat (Avena fatua)	9	9	9	9	9	9
Onion (Allium cepa)	9	9	9	8.5	8	7
Sugar beet (Beta vulgaris)	9	9	9	9	9	9
Oilseed rape (Brassica napus)	9	9	9	9	9	9
Soybean (Glycine max)	9	9	9	8	8	8

(A) Mean of two replicates; rating scale of 0 to 9 (comparison to controls), where 1 represented complete destruction or no emergence, and 9 no effect, similar to untreated

Table 3. Phtyotoxicity assessment categories used at the time of generation of non-target plant screening data 

Score	9	8	7	6	5	4	3	2	1
% damage	0	12.5	25	37.5	50	62.5	75	87.5	100

 

Validity criteria fulfilled:

yes

Remarks:

See guidelines and limitations in 'Any other information on materials and methods incl. tables'

Conclusions:

Based on a seedling emergence and vegetative vigour study, without following guidelines, but well documented and meets generally accepted scientific principles, the 14-d NOER for vegetative vigour was established to be 37.5 g product/ha (equivalent to 9.38 g test substance/ha). The 21-d NOER for seedling emergence was established to be 300 g product/ha (equivalent to 75 g test substance/ha).

Executive summary:

In a greenhouse screening study, the formulation of the test substance (containing 250 g test substance/kg) was applied to three monocot and three dicot crops at doses of 18.75, 37.5, 75, 150, 300 and 600 g product/ha and a negative (water) control. The study was performed without following guideline and was not in compliance with GLP. However, the study was well documented and meets generally accepted scientific principles. Thus, it is considered acceptable for assessment. Applications were made in 500 L of water per ha either pre-emergence (application to the soil surface within 24 hours from planting the seeds) or post-emergence (applications to the plant canopy 14 - 17 days after emergence) of target plants using a laboratory sprayer. Each treatment was tested in 2 replicates containing 3 (maize and soybean), 5 (sugar beet), 6 (wild oat) or 20 (oilseed rape and onion) seeds or plants per tray. Assessments of phytotoxicity were made at 21 days (emergence test) or 14 days (vegetative vigour test) after treatment by visual observations using a rating scale of 0 to 9 (comparison to controls), where 1 represented complete destruction or no emergence, and 9 no effect, similar to untreated. Test conditions were as following: 18 - 27°C (maize and soybean) or 15 – 22 °C (wild oat, onion, sugar beet and oilseed rape), relative humidity 40 - 60%, light >10000 lux (14-hour light period). Soil characteristics: clay loam ( 26% clay, 34% silt and 40% sand, 2.6% oc, pH 7.5). Evaluation of phytotoxicity was by visual observations that used a rating scale ranging from 1 (complete destruction or no emergence of the plants) to 9 (no effect, similar to untreated). Individual scoring was always as compared to the untreated control.

In the seedling emergence test, a mean visual effect rating of 6.5 on onion was observed in the 600 g product /ha test substance formulation. No effect of the test item could be detected in any of the other treated groups. In the vegetative vigour test, effects were observed in ≥ 75 g product /ha treated Maize groups, ≥ 150 g product /ha treated wild oat, and ≥ 150 g product /ha treated soybean.No effect of the test item could be detected in any of the other treated groups. Based on the findings, the 14-d NOER for vegetative vigour was established to be 37.5 g product/ha (equivalent to 9.38 g test substance/ha). The 21-d NOER for seedling emergence was established to be 300 g product/ha (equivalent to 75 g test substance/ha).

Reference 3

Endpoint:

toxicity to terrestrial plants: short-term

Type of information:

experimental study

Adequacy of study:

key study

Study period:

6 Jun 2007 to 28 Sep 2007

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 208 (Terrestrial Plants, Growth Test)

Version / remarks:

2006

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

Samples of 40 g of soil at each test level (including negative and solvent controls) in order to verify test substance concentration. Triplicate samples were collected from the highest- and lowest-concentration soils in order to demonstrate homogeneity of the test substance in the carrier (soil).

Vehicle:

yes

Remarks:

Acetone

Details on preparation and application of test substrate:

- Method of mixing into soil: A primary stock solution was prepared by diluting 39.60 g or 37.63 g of the liquified test substance with 200 mL of acetone, and mixing by stirring and sonication. Proportional dilutions of the stock solution were made on both days using 0.41, 1.23, 3.7, 11.1, and 33.3 mL of the primary stock, each diluted to 100 mL with acetone. The 100 mL stock solutions were then added to beakers containing 200 g of sand and stirred. One hundred mL of the undiluted primary stock solution was mixed with sand for preparation of the highest-concentration test soil. A one kilogram pre-mix was then prepared by adding the stock/sand mixture to a second beaker containing 800 g of artificial soil and stirring to mix. A negative control pre-mix was prepared from 200 g sand and 800 g artificial soil, and a solvent control pre-mix was prepared using 100 mL acetone mixed with 200 g sand and 800 g artificial soil. Test soils were prepared by adding the one kg pre-mixes to 29 kg of artificial soil and mixing for a total of approximately 20 minutes in a soil mixer.
- Controls: negative control and vehicle control
- Chemical name of vehicle: Acetone
- Concentration of vehicle in test medium: 2 %

Species:

Triticum aestivum

Plant group:

Monocotyledonae (monocots)

Details on test organisms:

- Common name: wheat
- Plant family: Poaceae
- Variety: Polk
- Historical germination of seed: 85 %

Species:

Brassica napus

Plant group:

Dicotyledonae (dicots)

Details on test organisms:

- Common name: oilseed rape
- Plant family: Brassicaceae
- Variety: Dwarf Essex
- Historical germination of seed: 85 %

Species:

Lactuca sativa

Plant group:

Dicotyledonae (dicots)

Details on test organisms:

- Common name: Lettuce
- Plant family: Astraceae
- Variety: Summertime
- Historical germination of seed: 98 %

Test type:

seedling emergence toxicity test

Study type:

laboratory study

Substrate type:

artificial soil

Limit test:

no

Total exposure duration:

21 d

Test temperature:

Mean (T. aestivum and B. napus): 26.15 ± 1.57 °C
Mean (L. sativa): 25.09 ± 1.60 °C

Details on test conditions:

TEST SYSTEM
- Test container: plastic pots (approximately 16 cm in diameter and 12 cm deep)
- Amount of soil: 1940 cm3 soil volume
- Method of seeding: Soil was added to the pots and a template was used to gently compact the soil and leave ten uniform holes for planting. One
indiscriminately selected seed was then planted in each hole, for a total of ten seeds in each pot. Holes were then closed by depressing the soil surface. T. aestivum seeds were planted at an approximate depth of 20 mm, while B. napus and L. sativa seeds were planted at an approximate depth of 6 mm.
- No. of seeds per container: 10
- No. of replicates per treatment group: 4
- No. of replicates per control: 4
- No. of replicates per vehicle control: 4

SOURCE AND PROPERTIES OF SUBSTRATE
- % sand: 75
- % silt: 11
- % clay: 14
- % organic matter: 1.3
- Soil taxonomic classification: sandy loam

GROWTH CONDITIONS
- Photoperiod: 16 hours light / 8 hours dark
- Light source: artificial lightning (high pressure sodium)
- Light intensity (moles Photosynthetically Active Radiation): Mean (T. aestivum and B. napus): 14.2 ± 0.6; Mean (L. sativa): 11.3 ± 0.7
- Relative humidity (%): Mean (T. aestivum and B. napus): 65.64 ± 8.30; Mean (L. sativa): 66.19 ± 8.73

EFFECT PARAMETERS MEASURED:
- Observations: Observations of the test were made on days 7 and 14 to document seedling emergence. Observations were made on day 21 to document seedling emergence and growth, and to determine the general condition of seedlings. Observations consisted of noting whether emergence had or had not occurred and assessing the condition of each seedling. Emergence was defined as the presence of visible plant tissue at the surface of the soil. Seedling condition was described by noting the presence or absence of possible signs of phytotoxicity such as necrosis, leaf wrinkle, chlorosis, plant lodging or plant stunting. Each emerged seedling was then assigned a numerical score that described the plant condition. Condition score is a subjective or qualitative assessment that determines whether damage is slight, moderate, or severe. A score of 10 does not mean that 10% of the plant is showing the effect (e.g. chlorosis), merely that the severity of the effect (e.g. chlorosis) is very slight.
- Growth measurement: The growth of emerged seedlings was evaluated on day 21 by assessing the height and biomass of seedlings. Plant biomass was estimated by measuring the total dry weight of the shoots within each replicate. Seedling height was measured with a ruler to the nearest whole centimetre from the surface of the soil to the tip of the tallest leaf. Dead or non-emerged seedlings were assigned a height of 0 cm. Seedlings were then clipped at soil level, the shoots of all living seedlings within a replicate were placed in a labelled paper container, dried in an oven, and weighed as a group. Mean seedling height and replicate biomass were determined for each treatment group at test termination.
- Phytotoxicity rating system: Rating scale adapted from: Frans, Robert E. and Ronald E. Talbert. 1977. Design of Field Experiments and the Measurement and Analysis of Plant Responses. Pages 15-23 in B. Truelove, ed. Research Methods in Weed Science. Southern Weed Science Society, Auburn University, Alabama.

VEHICLE CONTROL PERFORMED: Yes

Nominal and measured concentrations:

Nominal concentrations: 0 (negative control), 0 (solvent control), 3, 9, 27, 80, 240, and 720 mg ai/kg soil dry weight.

Reference substance (positive control):

no

Key result

Species:

Lactuca sativa

Duration:

21 d

Dose descriptor:

EC50

Effect conc.:

88.2 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

other: Biomass

Key result

Species:

Lactuca sativa

Duration:

21 d

Dose descriptor:

NOEC

Effect conc.:

27 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

other: Height and biomass

Key result

Species:

Brassica napus

Duration:

21 d

Dose descriptor:

NOEC

Effect conc.:

27 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

other: Height and biomass

Species:

Brassica napus

Duration:

21 d

Dose descriptor:

EC50

Effect conc.:

131 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

other: Biomass

Species:

Triticum aestivum

Duration:

21 d

Dose descriptor:

EC50

Effect conc.:

> 720 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Remarks on result:

other: No effects at the highest concentration tested

Species:

Triticum aestivum

Duration:

21 d

Dose descriptor:

NOEC

Effect conc.:

720 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Remarks on result:

other: No effects were observed with the highest concentration used

Details on results:

An overview of the analytical results is provided in Table 1 in 'Any otherinformation on materials and methods incl. tables'.
An overview of the biological effect results is provided in Table 2 - Table 5 in 'Any otherinformation on results incl. tables'.

No effects on the emergence, survival, condition, height, or biomass of any of the species were observed in the solvent control groups. Therefore, the results from the negative and solvent controls of all species were pooled for the statistical analyses of the treatment groups.

SEED GERMINATION AND SEEDLING EMERGENCE
There were no apparent effects on the emergence or survival for any species. Incidental signs of toxicity such as chlorosis, necrosis, and leaf curl were observed, but were intermittent and were not attributed to the test substance. Apparent treatment-related effects on plant condition, including slight to moderate leaf curl and/or chlorosis, were observed on B. napus at the 80, 240 and 720 mg/kg concentrations. T. aestivum seedlings in the 240 and 720 mg/kg groups showed slight necrosis and leaf curl. A few L. sativa seedlings of replicates in the 240 and 720 mg/kg groups showed varying degrees of necrosis and chlorosis, most seedlings appeared normal.

Reductions in mean biomass of T. aestivum seedlings were observed in the 240 and 720 mg ai/kg groups. The reductions may have been treatment related, as they were consistent with observed effects on plant condition. However, the biomass reductions were not statistically significant (p > 0.05), and were less than 25% in magnitude.

Reported statistics and error estimates:

Mean seedling emergence, survival, biomass, and height of the control and treatment groups were compared in the test with a Dunnett’s t-test, using the DUNNETT option of the GLM (general linear model) procedure of SAS. Significance was determined at the level of 0.05.
Statistical analyses for species also included the determination of effect concentrations (EC estimates) and their confidence limits. When possible, calculations were made using the non-linear regression analysis of Bruce and Versteeg. Analyses were conducted using the NLIN procedure of SAS Version 8.

Table 2. Effects of the test substance on Triticum aestivum(Wheat) Seedling Emergence, Survival, Biomass, and Height in a 21-Day Seedling Emergence Test

Treatment Group (mg ai/kg)	Emergence (per 10 Planted Seeds) Mean ± SD (% Reduction)	Emergence (per 10 Planted Seeds) Mean ± SD (% Reduction)	Emergence (per 10 Planted Seeds) Mean ± SD (% Reduction)	Survival (per 10 Planted Seeds) Mean ± SD (% Reduction)	Biomass (g) Mean ± SD (% Reduction)	Height (cm) Mean ± SD (% Reduction)
	7 DAA	14 DAA	21 DAA	21 DAA	21 DAA	21 DAA
Pooled Control	8.75 ± 0.71	8.88 ± 0.83	8.88 ± 0.83	8.75 ± 0.71	2.56 ± 0.367	35.8 ± 2.58
3	9.00 ± 1.15 (-3%)	9.00 ± 1.15 (-1%)	9.00 ± 1.15 (-1%)	9.00 ± 1.15 (-3%)	2.57 ± 0.648 (0%)	36.2 ± 4.93 (-1%)
9	9.25 ± 0.96 (-6%)	9.50 ± 1.00 (-7%)	9.50 ± 1.00 (-7%)	9.50 ± 1.00 (-9%)	3.14 ± 0.513 (-22%)	39.6 ± 5.31 (-11%)
27	8.75 ± 1.50 (0%)	8.75 ± 1.50 (1%)	8.75 ± 1.50 (1%)	8.75 ± 1.50 (0%)	2.43 ± 0.109 (5%)	34.1 ± 4.61 (5%)
80	8.50 ± 1.73 (3%)	8.50 ± 1.73 (4%)	8.50 ± 1.73 (4%)	8.50 ± 1.73 (3%)	2.28 ± 0.561 (11%)	32.5 ± 7.50 (9%)
240	9.00 ± 1.41 (-3%)	9.00 ± 1.41 (-1%)	9.00 ± 1.41 (-1%)	8.75 ± 1.89 (0%)	1.99 ± 0.667 (22%)	33.2 ± 8.46 (7%)
720	9.75 ± 0.50 (-11%)	9.75 ± 0.50 (-10%)	9.75 ± 0.50 (-10%)	9.75 ± 0.50 (-11%)	2.01 ± 0.222 (22%)	35.5 ± 0.88 (1%)

* - Treatment group mean is significantly different from the pooled control mean (p < 0.05).

Mean ± SD = Mean plus or minus one standard deviation.

DAA – Days After Application

 

Table 3. Effects of the test substance on Brassica napus (Oilseed Rape) Seedling Emergence, Survival, Biomass, and Height in a 21-Day Seedling Emergence Test 

Treatment Group (mg ai/kg)	Emergence (per 10 Planted Seeds) Mean ± SD (% Reduction)	Emergence (per 10 Planted Seeds) Mean ± SD (% Reduction)	Emergence (per 10 Planted Seeds) Mean ± SD (% Reduction)	Survival (per 10 Planted Seeds) Mean ± SD (% Reduction)	Biomass (g) Mean ± SD (% Reduction)	Height (cm) Mean ± SD (% Reduction)
	7 DAA	14 DAA	21 DAA	21 DAA	21 DAA	21 DAA
Pooled Control	8.00 ± 1.20	8.13 ± 1.25	8.13 ± 1.25	8.13 ± 1.25	7.00 ± 1.275	19.7 ± 2.73
3	6.75 ± 0.50 (16%)	6.75 ± 0.50 (17%)	7.50 ± 0.58 (8%)	7.50 ± 0.58 (8%)	6.07 ± 1.227 (13%)	15.7 ± 2.38 (20%)
9	7.50 ± 1.73 (6%)	7.50 ± 1.73 (8%)	7.50 ± 1.73 (8%)	7.50 ± 1.73 (8%)	5.96 ± 1.549 (15%)	17.8 ± 4.90 (10%)
27	8.50 ± 0.58 (-6%)	8.50 ± 0.58 (-5%)	8.50 ± 0.58 (-5%)	8.50 ± 0.58 (-5%)	6.87 ± 1.063 (2%)	20.8 ± 2.16 (-5%)
80	8.25 ± 0.96 (-3%)	8.25 ± 0.96 (-2%)	8.25 ± 0.96 (-2%)	8.25 ± 0.96 (-2%)	3.69 ± 0.485** (47%)	15.5 ± 1.24* (21%)
240	8.25 ± 0.50 (-3%)	8.25 ± 0.50 (-2%)	8.25 ± 0.50 (-2%)	8.00 ± 0.00 (2%)	2.05 ± 0.296** (71%)	10.2 ± 1.24* (48%)
720	7.75 ± 2.22 (3%)	7.75 ± 2.22 (5%)	7.75 ± 2.22 (5%)	7.75 ± 2.22 (5%)	1.58 ± 0.716** (77%)	8.0 ± 3.07* (59%)

* - Treatment group mean is significantly different from the pooled control mean (p < 0.05).

Mean ± SD = Mean plus or minus one standard deviation.

DAA – Days After Application

 

Table 4 Effects of the test substance on Lactuca sativa (Lettuce) Seedling Emergence, Survival, Biomass, and Height in a 21-Day Seedling Emergence Test

Treatment Group (mg ai/kg)	Emergence (per 10 Planted Seeds) Mean ± SD (% Reduction)	Emergence (per 10 Planted Seeds) Mean ± SD (% Reduction)	Emergence (per 10 Planted Seeds) Mean ± SD (% Reduction)	Survival (per 10 Planted Seeds) Mean ± SD (% Reduction)	Biomass (g) Mean ± SD (% Reduction)	Height (cm) Mean ± SD (% Reduction)
	7 DAA	14 DAA	21 DAA	21 DAA	21 DAA	21 DAA
Pooled Control	9.38 ± 0.74	9.50 ± 0.53	9.50 ± 0.53	9.50± 0.53	2.76 ± 0.676	11.3 ± 1.28
3	9.25 ± 0.50 (1%)	9.25 ± 0.50 (3%)	9.25 ± 0.50 (3%)	9.25± 0.50 (3%)	2.70 ± 0.910 (2%)	11.7 ± 1.16 (-3%)
9	9.00 ± 0.82 (4%)	9.75 ± 0.50 (-3%)	9.75 ± 0.50 (-3%)	8.75± 1.89 (8%)	2.43 ± 1.047 (12%)	10.4 ± 2.97 (8%)
27	9.75 ± 0.50 (-4%)	9.75 ± 0.50 (-3%)	9.75 ± 0.50 (-3%)	9.75± 0.50 (-3%)	2.37 ± 0.283 (14%)	10.6 ± 0.62 (7%)
80	9.50 ± 1.00 (-1%)	9.50 ± 1.00 (0%)	9.50 ± 1.00 (0%)	9.25± 0.96 (3%)	1.38 ± 0.445* (50%)	7.7 ± 0.74* (32%)
240	9.25 ± 0.96 (1%)	9.25 ± 0.96 (3%)	9.25 ± 0.96 (3%)	9.25± 0.96 (3%)	0.64 ± 0.145* (77%)	4.0 ± 1.10* (65%)
720	8.75 ± 0.96 (7%)	8.75 ± 0.96 (8%)	8.75 ± 0.96 (8%)	8.75± 0.96 (8%)	0.41 ± 0.093* (85%)	3.3 ± 0.52* (71%)

* - Treatment group mean is significantly different from the pooled control mean (p<0.05).

Mean ± SD = Mean plus or minus one standard deviation.

DAA – Days After Application

Table 5. The Relative Sensitivity and Most Sensitive Endpoint of Three Species in Response to Pre- Emergent Soil-Incorporated test substance

Species Latin name (common name)	Family	EC50	EC50	NOEC	NOEC
		Relative Sensitivity (mg ai/kg)	Most Sensitive Endpoint	NOEC (mg ai/kg)	Most Sensitive Endpoints
Triticum aestivum(wheat)	Poaceae	> 720	-^1	720	-^2
Brassica napus(oilseed rape)	Brassicaceae	131	Biomass	27	Biomass, Height
Lactuca sativa (lettuce)	Asteraceae	88.2	Biomass	27	Biomass, Height

¹– Not applicable since there was no adverse effect greater than 50%.

²– Not applicable since there was no LOEC.

Validity criteria fulfilled:

yes

Remarks:

See Validity of the Test in 'Any other information on materials and methids incl. tables'

Conclusions:

In a seedling emergence and growth test, following OECD TG 208, the 21-d EC50 and NOEC values were determined to be 88.2 mg/kg soil dw and 27 mg/kg soil dw, respectively.

Executive summary:

A study was performed to determine the effects of the test substance on the seedling emergence and growth (height and biomass) of 3 non-target plants (one monocotyledonae and two dicotyledonae plant species). This study followed the OECD 227 guidance and was performed in compliance with GLP criteria. The species were exposed to the following nominal concentrations of the test substance: 0 (negative control), 0 (solvent control, acetone), 3, 9, 27, 80, 240, and 720 mg ai/kg soil dry weight. Each group had four replicate pots with ten seeds planted in each pot. A single application of the test substance was made to the treatment groups by soil incorporation, while the negative and solvent control soils had no test substance added. Seeds were impartially assigned to prelabelled growth pots on the day of test initiation. The replicate pots were placed in a randomized block design on a glasshouse table after planting occurred. Observations of emergence were made on days 7, 14, and 21, while observations of height and condition were made only on day 21. Dry weights were determined from seedling shoots collected at test termination on day 21.

There were no apparent effects on the emergence or survival for any species. Incidental signs of toxicity such as chlorosis, necrosis, and leaf curl were observed, but were intermittent and were not attributed to the test substance. Apparent treatment-related effects on plant condition, including slight to moderate leaf curl and/or chlorosis, were observed on B. napus at the 80, 240 and 720 mg/kg concentrations. T. aestivum seedlings in the 240 and 720 mg/kg groups showed slight necrosis and leaf curl. A few L. sativa seedlings of replicates in the 240 and 720 mg/kg groups showed varying degrees of necrosis and chlorosis, most seedlings appeared normal.

 Reductions in mean biomass of T. aestivum seedlings were observed in the 240 and 720 mg/kg groups. The reductions may have been treatment related, as they were consistent with observed effects on plant condition. However, the biomass reductions were not statistically significant (p> 0.05), and were less than 25% in magnitude. Based on the finding, the EC50 values for biomass of B. napus and L. sativa were calculated to be 131 mg/kg soil dw and 88.2 mg/kg soil dw, respectively. The NOEC values for height and biomass of B. napus and L. sativa were 27 mg/kg soil dw. Effects on the condition of T. aestivum were not noted 21 days after planting.

Description of key information

All available data was assessed and the study representing the worst-case effect is included here as key. The result can be considered worst-case and is selected for the CSA.

21-d NOEC = 27 mg/kg soil dw, Brassica napus and Lactuca sativa, height and biomass, OECD TG 208, Porch, 2007

21-d EC50 = 88.2 mg/kg soil dw, Lactuca sativa, phytotoxicity, OECD TG 208, Porch, 2007

Key value for chemical safety assessment

Short-term EC50 or LC50 for terrestrial plants:

88.2 mg/kg soil dw

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

27 mg/kg soil dw

Additional information

OECD TG 208, Porch 2007

A study was performed to determine the effects of the test substance on the seedling emergence and growth (height and biomass) of 3 non-target plants (one monocotyledonae and two dicotyledonae plant species). This study followed the OECD 227 guidance and was performed in compliance with GLP criteria. The species were exposed to the following nominal concentrations of the test substance: 0 (negative control), 0 (solvent control, acetone), 3, 9, 27, 80, 240, and 720 mg ai/kg soil dry weight. Each group had four replicate pots with ten seeds planted in each pot. A single application of the test substance was made to the treatment groups by soil incorporation, while the negative and solvent control soils had no test substance added. Seeds were impartially assigned to prelabelled growth pots on the day of test initiation. The replicate pots were placed in a randomized block design on a glasshouse table after planting occurred. Observations of emergence were made on days 7, 14, and 21, while observations of height and condition were made only on day 21. Dry weights were determined from seedling shoots collected at test termination on day 21.

There were no apparent effects on the emergence or survival for any species. Incidental signs of toxicity such as chlorosis, necrosis, and leaf curl were observed, but were intermittent and were not attributed to the test substance. Apparent treatment-related effects on plant condition, including slight to moderate leaf curl and/or chlorosis, were observed on B. napus at the 80, 240 and 720 mg/kg concentrations. T. aestivum seedlings in the 240 and 720 mg/kg groups showed slight necrosis and leaf curl. A few L. sativa seedlings of replicates in the 240 and 720 mg/kg groups showed varying degrees of necrosis and chlorosis, most seedlings appeared normal.

 Reductions in mean biomass of T. aestivum seedlings were observed in the 240 and 720 mg/kg groups. The reductions may have been treatment related, as they were consistent with observed effects on plant condition. However, the biomass reductions were not statistically significant (p> 0.05), and were less than 25% in magnitude. Based on the finding, the EC50 values for biomass of B. napus and L. sativa were calculated to be 131 mg/kg soil dw and 88.2 mg/kg soil dw, respectively. The NOEC values for height and biomass of B. napus and L. sativa were 27 mg/kg soil dw. Effects on the condition of T. aestivum were not noted at all 21 days after planting.

Supporting studies

Seedling emergence and vegetative vigour, Walder 2000a

In a greenhouse screening study, the formulation (WG25 containing 250 g test substance/kg) of the test substance was applied to three monocot and three dicot crops at doses of 56.25, 112.5, 225, 450, 900 and 1800 g/ha and a negative (water) control. The study was performed without following guideline and not in compliance with GLP. However, the study was well documented and meets generally accepted scientific principles. Thus, it is considered acceptable for assessment. Applications were made in 500 L of water per ha either pre-emergence (application to the soil surface within 24 hours from planting the seeds) or postemergence (applications to the plant canopy 14 - 17 days after emergence) of target plants using a laboratory sprayer. Each treatment was tested in 2 replicates containing 3 (maize and soybean), 5 (sugar beet) 6 (wild oat) or 20 (oilseed rape and onion) seeds or plants per tray. Visual phytotoxicity ratings were recorded 16 and 21 days after the application of the test item for vegetative vigour and seedling emergence, respectively. Test conditions were as following: 18 - 27°C (maize and soybean) or 15 - 22°C (wild oat, onion, sugar beet and oilseed rape), relative humidity 40 - 60%, light >10000 lux (14-hour light period). Soil characteristics: clay loam ( 26% clay, 34% silt and 40% sand, 2.6% OC, pH 7.5). Evaluation of phytotoxicity was by visual observations that used a rating scale ranging from 1 (complete destruction or no emergence of the plants) to 9 (no effect, similar to untreated). Individual scoring was always as compared to the untreated control.

No effect of the test item could be detected in any of the treatments in the seedling emergence test. In the vegetative vigour test, a mean visual effect rating of 6 on oilseed rape was observed in the1800 g product /ha and of 8 in the 900 g product /ha. No effect of the test item could be detected in any of the other treatments. Based on the findings, the 16 -d NOER for vegetative vigour was established to be 450 g product /ha (equivalent to 112.5 g test substance/ha).

Seedling emergence and vegetative vigour, Walder 2000b

In a greenhouse screening study, the formulation of the test substance (WG25 containing 250 g test substance/kg) was applied to three monocot and three dicot crops at doses of 18.75, 37.5, 75, 150, 300 and 600 g product/ha and a negative (water) control.The study was performed without following a specific test guideline and was not in compliance with GLP. However, the study was well documented and meets generally accepted scientific principles. Thus, it is considered acceptable for assessment. Applications were made in 500 L of water per ha either pre-emergence (application to the soil surface within 24 hours from planting the seeds) or post-emergence (applications to the plant canopy 14 - 17 days after emergence) of target plants using a laboratory sprayer. Each treatment was tested in 2 replicates containing 3 (maize and soybean), 5 (sugar beet), 6 (wild oat) or 20 (oilseed rape and onion) seeds or plants per tray. Assessments of phytotoxicity were made at 21 days (emergence test) or 14 days (vegetative vigour test) after treatment. Test conditions were as following: 18 - 27°C (maize and soybean) or 15 – 22 °C (wild oat, onion, sugar beet and oilseed rape), relative humidity 40 - 60%, light >10000 lux (14-hour light period). Soil characteristics: clay loam ( 26% clay, 34% silt and 40% sand, 2.6% OC, pH 7.5). Evaluation of phytotoxicity was by visual observations that used a rating scale ranging from 1 (complete destruction or no emergence of the plants) to 9 (no effect, similar to untreated). Individual scoring was always as compared to the untreated control.

In the seedling emergence test, a mean visual effect rating of 6.5 on onion was observed in the 600 g product /ha treatment. No effect of the test item could be detected in any of the other treated groups. In the vegetative vigour test, effects were observed in ≥ 75 g product /ha treated Maize groups, ≥ 150 g product /ha treated wild oat and soybean groups. No effect of the test item could be detected in any of the other treated groups. Based on the findings, the 14-d NOER for vegetative vigour was established to be 37.5 g product/ha (equivalent to 9.38 g test substance/ha). The 21-d NOER for seedling emergence was established to be 300 g product/ha (equivalent to 75 g test substance/ha).