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Ecotoxicological information

Toxicity to terrestrial plants

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Reference
Endpoint:
toxicity to terrestrial plants: short-term (with study design considered suitable for long-term assessment)
Type of information:
experimental study
Adequacy of study:
key study
Study period:
18 November 2015 to 9 December 2015
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)
GLP compliance:
yes (incl. QA statement)
Specific details on test material used for the study:
See test material information
Analytical monitoring:
no
Vehicle:
no
Details on preparation and application of test substrate:
A definitive test was undertaken using the concentrations of 0 (control), 95, 172, 309, 556 and 1000 mg product/kg dry substrate.
The organic carbon content of test substrate was determined to be 2.5%, which was above that specified for use in the test. As a result, the test substrate was cut with industrial quartz sand prior to use, to achieve an organic carbon content of <1.5%.
- Method of mixing into soil (if used): As the test substance was not readily soluble in water, it was applied to the test substrate using a sand carrier.
Sand stocks for each treatment group were prepared by adding the appropriate amount of test substance into a 1.0 L glass jar containing a pre-weighed volume of sand. The glass jars were then sealed, placed in a cement mixer, and rolled for a total of 75 minutes to homogenise the mixtures. Following homogenisation in the cement mixture, and due to the capacity of the mixer used for test substrate mixing, the treated sand was divided into three even sub-samples per concentration.
The test substrate was prepared in bulk, consisting of a total of 20.4 kg dry weight per test concentration, prepared in three sub-batches per test concentration. Per sub-batch, approximately half of the test substrate was placed in a stainless steel Hobart mechanical mixer, and the test substance, incorporated into sand, was evenly distributed across the surface of the test substrate within the mixer. The remaining substrate was then placed on top of this, without disturbing the sand layer, prior to mixing. Each test concentration was thoroughly mixed for 5-minutes, followed by a thorough hand-turn. At this point, approximately 100 mL of mains water was added to the mixture, followed by an additional 5 minute mechanical mix. This was deemed sufficient to thoroughly incorporate the test substance into the test substrate.

Test vessels were placed in large plastic garden trays, with each tray holding one whole test concentration (24 pots). Test concentrations were maintained separately to avoid contamination between concentrations.
Following test substrate preparation, each prepared test concentration was evenly allocated to the respective test vessels, equivalent to approximately 850 g dry weight per replicate.

The seeds were sown at an appropriate depth for each species, and were spaced according to the number of seeds per pot. Sowing depth was achieved by the use of the bulb end of a disposable Pasteur pipette, delineated to allow for consistent planting depths.
The seeds were sown on the same day as treatment application, following test substrate preparation.
Seedlings were maintained in a Weiss Gallenkamp Fitotron Incubator for the duration of the test
- Controls: Test substrate with no test substance
Species:
Brassica rapa
Plant group:
Dicotyledonae (dicots)
Details on test organisms:
- Common name: Turnip
- Plant family:
- Variety: Golden Ball/White Globe
- Source of seed: Chase Garden
- Prior seed treatment/sterilization:
- Historical germination of seed (germination of seed lot tested):
- Seed storage:
Species:
other: Solanum lycopersicum
Plant group:
Dicotyledonae (dicots)
Details on test organisms:
- Common name: Tomato
- Plant family:
- Variety: Moneymaker
- Source of seed: Chase Garden
- Prior seed treatment/sterilization:
- Historical germination of seed (germination of seed lot tested):
- Seed storage:
Species:
Phaseolus vulgaris
Plant group:
Dicotyledonae (dicots)
Details on test organisms:
- Common name: Dwarf bean
- Plant family:
- Variety: The Prince
- Source of seed: Chase Garden
- Prior seed treatment/sterilization:
- Historical germination of seed (germination of seed lot tested):
- Seed storage:
Species:
other: Fagopyrum esculentum
Plant group:
Dicotyledonae (dicots)
Details on test organisms:
- Common name: Buckwheat
- Plant family:
- Variety: Not available
- Source of seed: Chase Garden
- Prior seed treatment/sterilization:
- Historical germination of seed (germination of seed lot tested):
- Seed storage:
Species:
Triticum aestivum
Plant group:
Monocotyledonae (monocots)
Details on test organisms:
- Common name: Wheat
- Plant family:
- Variety: Not available
- Source of seed: Infinity Foods
- Prior seed treatment/sterilization:
- Historical germination of seed (germination of seed lot tested):
- Seed storage:
Species:
Lolium perenne
Plant group:
Monocotyledonae (monocots)
Details on test organisms:
- Common name: Ryegrass
- Plant family:
- Variety: Not available
- Source of seed: Westerworlds Annual Ryegrass
- Prior seed treatment/sterilization:
- Historical germination of seed (germination of seed lot tested):
- Seed storage:
Test type:
seedling emergence and seedling growth test
Study type:
laboratory study
Substrate type:
natural soil
Limit test:
no
Total exposure duration:
21 d
Test temperature:
21.3 - 27.3 °C
pH:
6.15
Moisture:
The wet:dry ratio was determined to be 1.11
Details on test conditions:
TEST SYSTEM
- Testing facility: Smithers Viscient greenhouse
- Test container (type, material, size): 11 × 11 × 12 cm injection-moulded square pots, with both base and side drainage holes.
- Amount of soil: 850 g dry weight per replicate
- Method of seeding: The seeds were sown at an appropriate depth for each species, and were spaced according to the number of seeds per pot.
- No. of seeds per container: 5
- No. of plants (retained after thinning): not reported
- No. of replicates per treatment group: 4
- No. of replicates per control: 4

SOURCE AND PROPERTIES OF SUBSTRATE (if soil)
- Geographic location: Boughton Loam & Turf Management
- Pesticide use history at the collection site: Not reported
- Collection procedures: not reported
- Sampling depth (cm): not reported
- Soil texture (if natural soil) Sandy loam
- % sand: Very coarse sand 5000 - 2000 = 2%
Coarse sand 1000 - 500 = 3%
Medium sand 500 - 250 = 13%
Fine sand 250 - 125 = 16%
Very fine sand 125 - 60 = 7%
- % silt: Coarse silt 60 - 20 = 18%
Silt 60 - 21 = 17%
- % clay: Clay <2 = 23%
- Soil taxonomic classification: Not reported
- Soil classification system: Not reported
- Composition (if artificial substrate): n/a
- Organic carbon (%): Organic Carbon Content was determined to be 2.5 %; Organic Matter was calculated to be 4.3%.
- Maximum water holding capacity (in % dry weight): not reported
- CEC: not reported
- Pretreatment of soil: Upon receipt, the substrate was subjected to pH, moisture content analysis and organic matter / organic carbon content determination.
The organic carbon content of test substrate was determined to be 2.5%, which was above that specified for use in the test. As a result, the test substrate was cut with industrial quartz sand prior to use, to achieve an organic carbon content of <1.5%.
- Storage (condition, duration): not reported

NUTRIENT MEDIUM (if used)
- Description: none reported

GROWTH CONDITIONS
- Photoperiod: 16:8 hour light:dark cycle
- Light source: fluorescent lighting
- Light intensity and quality: 277-3140 LUX (lowest level: light intensity was reduced as the plants were observed to be growing very large under the conditions; reducing the light intensity is favourable in this instance as larger plants may begin to bend during the testing period, and should be avoided).
- Day/night temperatures: 21.3 - 27.3 oC
- Relative humidity (%): 57-93%
- Wind velocity: n/a - incubator
- Air exchange rate: not reported
- Watering regime and schedules: Plants were watered, as necessary, using mains water via a suitable hand sprayer.
Initially the pots were surface-watered and bottom-watered in trays, with effort being made not to disturb or flood the substrate. Once the seedlings were established, the pots were bottom-watered in the trays, as required, to prevent the drying of the substrate. No supplemental nutrients or feed were required during the test.
- Water source/type: mains water
- Volume applied: as necessary
- Interval of applications: as necessary
- Method of application: hand sprayer
- Any pest control method/fertilization (if used): no

ACCLIMATION PERIOD: not reported

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
Emergence
The number of emerged seeds was recorded per replicate. Emergence was assessed daily until the date of harvest.
Visual effects Observations
Qualitative assessment was made of visual phytotoxic effects. A scoring system was conducted based on percent effect per observation category. Percentage scores were assigned as a measure of the overall visual effects for all seedlings in one vessel, compared to the controls. For visual effects, the vessel was considered to be the replicate, and not the individual plants within each vessel.
Visual effects assessments were conducted at least weekly for a period of between 14 to 21 days after 50% emergence was achieved in the controls, and on the day of harvest.
Growth
The seedlings were harvested 16 days after each species had reached 50% control emergence. Seedlings were cut at the substrate surface, and weighed on a calibrated balance, to determine seedling wet weight (biomass).
- Phytotoxicity rating system (if used): percent effect per observation category

VEHICLE CONTROL PERFORMED: yes/no

TEST CONCENTRATIONS
- Spacing factor for test concentrations: Approximately 1.8
- Justification for using less concentrations than requested by guideline: n/a
- Range finding study
Spray Feasibility Trial
At the request of the Sponsor, a feasibility trial was conducted with the test substance to ascertain its suitability to a spray application, at an in-field application rate of 400 L/ha.
Prior to spraying, a 1000 g prod/ha solution was prepared by adding 25.00 mg of test substance to a suitable vessel with 25.47 mg of Span40 and 28.41 mg of Tween40. Following this, the solution was made up to a volume of 100 mL using the RO water/Span40/Tween40 mixture, was sonicated at approximately 35°C for 10 minutes and was then sonicated at approximately 50°C for a further 20 minutes. This produced an opaque solution with no visible undissolved material. The techniques used to produce the test substance solution were based on previous solubility trials performed on behalf of the Sponsor, and provided by the Sponsor to the Test Facility to be used as supporting data.
Surface spray application was made using a Laboratory Potter Spray Tower, calibrated at a volume equivalent to 400 L/ha water. The Potter Spray Tower was calibrated with RO water immediately prior to application, following procedures described in local SOPs. A target rate of 400 L/ha is equivalent to a deposit of 4 mg/cm2; acceptable limits of ± 10%, e.g. 3.6 to 4.4 mg/cm2 were applied. Eight consecutive calibration runs within the given limits were achieved with RO water prior to spraying.
The spraying of the 1000 g prod/ha solution was sequentially performed a total of 10 times.
Results:
Ten sequential sprays were performed using the laboratory Potter Spray Tower. It was observed that each spray was successful, and that there were no signs of an abnormal spray, i.e there was no indication of the spray nozzle being obstructed/blocked, and the coverage of the spray was observed to be even across the spray platform. The preparation of the Test Substance using Tween40/Span40 and RO water, as described, was therefore determined to be suitable for spray application.
Nominal and measured concentrations:
0 (control), 95, 172, 309, 556 and 1000 mg product/kg dry substrate
Reference substance (positive control):
not specified
Species:
Triticum aestivum
Duration:
21 d
Dose descriptor:
NOEC
Effect conc.:
1 000 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other: emergence, biomass and phytotoxicity
Species:
Triticum aestivum
Duration:
21 d
Dose descriptor:
EC50
Effect conc.:
> 1 000 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other: emergence, biomass and phytotoxicity
Species:
Brassica rapa
Duration:
21 d
Dose descriptor:
NOEC
Effect conc.:
1 000 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other: emergence, biomass and phytotoxicity
Species:
Brassica rapa
Duration:
21 d
Dose descriptor:
EC50
Effect conc.:
> 1 000 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other: emergence, biomass and phytotoxicity
Species:
other: Fagopyrum esculentum
Duration:
21 d
Dose descriptor:
NOEC
Effect conc.:
1 000 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other: emergence, biomass and phytotoxicity
Species:
other: Fagopyrum esculentum
Duration:
21 d
Dose descriptor:
EC50
Effect conc.:
> 1 000 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other: emergence, biomass and phytotoxicity
Species:
Phaseolus vulgaris
Duration:
21 d
Dose descriptor:
NOEC
Effect conc.:
1 000 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other: emergence and phytotoxicity
Species:
Phaseolus vulgaris
Duration:
21 d
Dose descriptor:
NOEC
Effect conc.:
309 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other: biomass
Remarks on result:
other: biomass determined from fresh seedling wet weight
Species:
other: Pkgseolus vulgaris
Duration:
21 d
Dose descriptor:
EC50
Effect conc.:
> 1 000 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other: emergence, biomass and phytotoxicity
Species:
Lolium perenne
Duration:
21 d
Dose descriptor:
NOEC
Effect conc.:
1 000 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other: emergence, biomass and phytotoxicity
Species:
Lolium perenne
Duration:
21 d
Dose descriptor:
EC50
Effect conc.:
> 1 000 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other: emergence, biomass and phytotoxicity
Species:
other: Solanum lycopersicum
Duration:
21 d
Dose descriptor:
NOEC
Effect conc.:
1 000 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other: emergence, biomass and phytotoxicity
Species:
other: Solanum lycopersicum
Duration:
21 d
Dose descriptor:
EC50
Effect conc.:
> 1 000 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other: emergence, biomass and phytotoxicity
Details on results:
Tomato showed an inverted dose response, where a significant effect was noted in the 556 mg product/kg test concentration (p = <0.05), as there was 50% emergence in the 556 mg product/kg test concentration at the time of harvest, when compared to 85% emergence in the control. The higher concentration of 1000 mg product/kg however, was determined to show no statistically significant difference in emergence when compared to the control, and therefore the NOEC and LOEC values for tomato emergence were determined to be 1000 and >1000 mg product/kg, respectively.

All seedling wet weight data was analysed using a Dunnetts Multiple Comparison test. Wheat, turnip, buckwheat, ryegrass and tomato were determined to show no significant differences in seedling wet weight, when compared to the controls, in any of the test concentrations.
Therefore, the NOEC and LOEC values for seedling wet weight for wheat, turnip, buckwheat, ryegrass and tomato were determined to be 1000 and >1000 mg product/kg, respectively. In wheat, turnip and tomato there was in general a positive effect on the biomass of the seedlings under the influence of the test substance.

The NOEC and LOEC values for dwarf bean seedling wet weight were determined to be 309 and 556 mg product/kg, respectively, based on a % reduction in biomass of -4, 3, 5, 31 and 23% when compared to the control, in the 95, 172, 309, 556 and 1000 mg product/kg treatment groups, respectively.
Furthermore, all biomass (seedling wet weight) data were analysed using Linear Interpolation (ICPIN) and the EC50 values were determined to be >1000 mg product/kg, for all test species.

Phytotoxicity
Minor phytotoxic effects at the date of harvest include partial shoot and stem stunting, wilting leaves and wilting stems. A small proportion of plants were also observed to be “dying”.
However, as the overall percentage of minor phytotoxic effects were low in all species at each observation interval, including at the date of harvest, the NOEC and LOEC, and EC50 values for all species were empirically determined to be 1000, >1000 and >1000 mg product/kg, respectively.
Results with reference substance (positive control):
n/a
Reported statistics and error estimates:
Statistical analysis of the data was undertaken using CETIS version 1.8.6.8, based on the nominal test concentrations. The following methods were used;
- Shapiro Wilk’s analysis of normality and analysis on equality of variance was performed, and a Dunnetts Multiple Comparison Test was used to determine the NOEC and LOEC values for emergence and seedling wet weight (biomass) for all test species.
- A Linear Interpolation Test (ICPIN) was used to determine the EC50 for emergence and seedling wet weight (biomass) for all test species.
The NOEC, LOEC and EC50 values for phytotoxic effects were determined empirically.

Table: Seedling Emergence Summary

Species

Test Concentration (mg product/kg dry substrate)

Mean % emergence

Wheat

0 (Control)

95

 

95

90

 

172

85

 

309

85

 

556

90

 

1000

90

Turnip

0 (Control)

80

 

95

95

 

172

90

 

309

90

 

556

80

 

1000

95

Buckwheat

0 (Control)

90

 

95

90

 

172

95

 

309

90

 

556

95

 

1000

90

Dwarf Bean

0 (Control)

100

 

95

100

 

172

95

 

309

100

 

556

95

 

1000

100

Ryegrass

0 (Control)

100

 

95

95

 

172

100

 

309

70

 

556

100

 

1000

95

Tomato

0 (Control)

85

 

95

70

 

172

60

 

309

65

 

556

50

 

1000

90

Table: Seedling Wet Weight Summary

Species

Test Concentration (mg product/kg dry substrate)

Mean Wet Weight (mg)

% Reduction compared to the control

Wheat

0 (Control)

217

N/A

 

95

370

-70

 

172

262

-21

 

309

236

-8

 

556

297

-37

 

1000

243

-12

Turnip

0 (Control)

72

N/A

 

95

54

25

 

172

149

-108

 

309

95

-33

 

556

138

-93

 

1000

89

-24

Buckwheat

0 (Control)

389

N/A

 

95

436

-12

 

172

373

4

 

309

318

18

 

556

398

-2

 

1000

385

1

Dwarf Bean

0 (Control)

5014

N/A

 

95

5234

-4

 

172

4839

3

 

309

4742

5

 

556

3440

31

 

1000

3867

23

Ryegrass

0 (Control)

104

N/A

 

95

120

-16

 

172

123

-18

 

309

83

20

 

556

99

5

 

1000

90

14

Tomato

0 (Control)

143

N/A

 

95

161

-12

 

172

205

-44

 

309

192

-34

 

556

169

-18

 

1000

165

-15

Validity criteria fulfilled:
yes
Conclusions:
The effect of the test item on seedling emergence and early growth of higher plants has been investigated. The results are as follows:
Test Rate mg product/kg dry substrate
Species Endpoint NOEC LOEC EC50
Wheat Emergence 1000 >1000 >1000
Biomass 1000 >1000 >1000
Phytotoxicity 1000 >1000 >1000
Turnip Emergence 1000 >1000 >1000
Biomass 1000 >1000 >1000
Phytotoxicity 1000 >1000 >1000
Buckwheat Emergence 1000 >1000 >1000
Biomass 1000 >1000 >1000
Phytotoxicity 1000 >1000 >1000
Dwarf Bean Emergence 1000 >1000 >1000
Biomass 309 556 >1000
Phytotoxicity 1000 >1000 >1000
Ryegrass Emergence 1000 >1000 >1000
Biomass 1000 >1000 >1000
Phytotoxicity 1000 >1000 >1000
Tomato Emergence 1000 >1000 >1000
Biomass 1000 >1000 >1000
Phytotoxicity 1000 >1000 >1000
Executive summary:

Introduction

A study was performed to determine the potential effects of the test substance on seedling emergence and early growth of higher plants.

Six seedling species, from a range of selected higher plants (monocotyledonae and dicotyledonae species), were exposed to the test substance incorporated into the test substrate. This study was conducted according to the procedures outlined in the study protocol. The protocol was based on the procedures specified in OECD Guideline 208 (OECD, 2006) (Terrestrial Plants Test: Seedling Emergence and Seedling Growth Test).

 

Methods….

A definitive test was conducted at the following test concentrations: 0 (control), 95, 172, 309, 556 and 1000 mg product/kg dry substrate, for a period of 21 days after seedling emergence.

As the test substance was not readily soluble in water, it was applied to the test substrate using a sand carrier.

Four replicate vessels were prepared for each test concentration and four replicate vessels were prepared for the control(s), each replicate containing five seeds per test vessel.

Assessment of effects on percent emergence, visual phytotoxicity and growth were conducted in comparison with the control treatment.

 

Results….

The no observable effect concentration (NOEC), the lowest observed effect concentration (LOEC), and the EC50 values were determined for seedling emergence, seedling wet weight (expressed as biomass), and phytotoxicity.

Based on nominal concentrations of the test substance, the results are as follows:

 

 

Test Rate mg product/kg dry substrate

 

 

Species

Endpoint

NOEC

LOEC

EC50

Wheat

Emergence

1000

>1000

>1000

 

Biomass

1000

>1000

>1000

 

Phytotoxicity

1000

>1000

>1000

Turnip

Emergence

1000

>1000

>1000

 

Biomass

1000

>1000

>1000

 

Phytotoxicity

1000

>1000

>1000

Buckwheat

Emergence

1000

>1000

>1000

 

Biomass

1000

>1000

>1000

 

Phytotoxicity

1000

>1000

>1000

Dwarf Bean

Emergence

1000

>1000

>1000

 

Biomass

309

556

>1000

 

Phytotoxicity

1000

>1000

>1000

Ryegrass

Emergence

1000

>1000

>1000

 

Biomass

1000

>1000

>1000

 

Phytotoxicity

1000

>1000

>1000

Tomato

Emergence

1000

>1000

>1000

 

Biomass

1000

>1000

>1000

 

Phytotoxicity

1000

>1000

>1000

Description of key information

A 21-day EC50 value of >1000 mg/kg dry soil and NOEC value of 1000 mg/kg dry soil (nominal concentrations) (highest concentration tested) have been determined for the effects of the test substance on seedling emergence, growth and phytotoxicity of wheat.

A 21-day EC50 value of >1000 mg/kg dry soil and NOEC value of 1000 mg/kg dry soil (nominal concentrations) (highest concentration tested) have been determined for the effects of the test substance on seedling emergence, growth and phytotoxicity of turnip.

A 21-day EC50 value of >1000 mg/kg dry soil and NOEC value of 1000 mg/kg dry soil (nominal concentrations) (highest concentration tested) have been determined for the effects of the test substance on seedling emergence, growth and phytotoxicity of buckwheat.

A 21-day EC50 value of >1000 mg/kg dry soil and NOEC value of 1000 mg/kg dry soil (nominal concentrations) (highest concentration tested) have been determined for the effects of the test substance on seedling emergence and phytotoxicity of dwarf bean.

A 21-day EC50 value of >1000 mg/kg dry soil and NOEC value of 309 mg/kg dry soil (nominal concentrations) have been determined for the effects of the test substance on growth of dwarf bean.

A 21-day EC50 value of >1000 mg/kg dry soil and NOEC value of 1000 mg/kg dry soil (nominal concentrations) (highest concentration tested) have been determined for the effects of the test substance on seedling emergence, growth and phytotoxicity of ryegrass.

A 21-day EC50 value of >1000 mg/kg dry soil and NOEC value of 1000 mg/kg dry soil (nominal concentrations) (highest concentration tested) have been determined for the effects of the test substance on seedling emergence, growth and phytotoxicity of tomato.

Key value for chemical safety assessment

Long-term EC10, LC10 or NOEC for terrestrial plants:
309 mg/kg soil dw

Additional information

Measured toxicity data are available for Shell GTL Solvent GS270 (Hydrocarbons, C15-C19, n-alkanes, isoalkanes, <2% aromatics) with six species of terrestrial higher plants: Turnip (Brassica rapa), Tomato (Solanum lycopersicum), Dwarf bean (Phaseolus vulgaris), Buckwheat (Fagopyrum esculentum), Wheat (Triticum aestivum) and Ryegrass (Lolium perenne) (Smithers Viscient, 2017). The test was conducted in accordance OECD Guideline 208 (Terrestrial Plants Test: Seedling Emergence and Seedling Growth Test).

As the test substance was not readily soluble in water, it was applied to the test substrate using a sand carrier. Five test substance concentrations of 0 (control), 95, 172, 309, 556 and 1000 mg product/kg dry substrate were tested. No analysis of test concentrations was carried out.

 

Assessment of effects on percent emergence, visual phytotoxicity and growth were conducted in comparison with the control treatment, after 21 days.

There was no effect of the test substance on emergence of any of the plants.

 

The NOEC and LOEC values for seedling wet weight for wheat, turnip, buckwheat, ryegrass and tomato were determined to be 1000 and >1000 mg product/kg, respectively.

The NOEC and LOEC values for dwarf bean seedling wet weight were determined to be 309 and 556 mg product/kg, respectively, based on a % reduction in biomass compared to the control.

 

Minor phytotoxic effects at the date of harvest include partial shoot and stem stunting, wilting leaves and wilting stems. A small proportion of plants were also observed to be “dying”.

However, as the overall percentage of minor phytotoxic effects were low in all species at each observation interval, including at the date of harvest, the NOEC and LOEC, and EC50 values for all species were empirically determined to be 1000, >1000 and >1000 mg product/kg, respectively.

The results are as follows in the Table below:

 

 

Test Rate mg product/kg dry substrate

 

 

Species

Endpoint

NOEC

LOEC

EC50

Wheat

Emergence

1000

>1000

>1000

 

Biomass

1000

>1000

>1000

 

Phytotoxicity

1000

>1000

>1000

Turnip

Emergence

1000

>1000

>1000

 

Biomass

1000

>1000

>1000

 

Phytotoxicity

1000

>1000

>1000

Buckwheat

Emergence

1000

>1000

>1000

 

Biomass

1000

>1000

>1000

 

Phytotoxicity

1000

>1000

>1000

Dwarf Bean

Emergence

1000

>1000

>1000

 

Biomass

309

556

>1000

 

Phytotoxicity

1000

>1000

>1000

Ryegrass

Emergence

1000

>1000

>1000

 

Biomass

1000

>1000

>1000

 

Phytotoxicity

1000

>1000

>1000

Tomato

Emergence

1000

>1000

>1000

 

Biomass

1000

>1000

>1000

 

Phytotoxicity

1000

>1000

>1000