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Ecotoxicological information

Toxicity to terrestrial plants

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Administrative data

Endpoint:
toxicity to terrestrial plants: short-term
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2017-04-26 to 2017-05-24
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
comparable to guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2017
Report date:
2017

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 208 (Terrestrial Plants, Growth Test)
Version / remarks:
OECD 208 (July 2006): Terrestrial Plant Test: Seedling Emergence and Seedling Growth Test
Deviations:
no
GLP compliance:
yes

Test material

1
Chemical structure
Reference substance name:
2,6-di-tert-butylphenol
EC Number:
204-884-0
EC Name:
2,6-di-tert-butylphenol
Cas Number:
128-39-2
Molecular formula:
C14H22O
IUPAC Name:
2,6-di-tert-butylphenol
Test material form:
solid
Details on test material:
- State of aggregation: White to yellow, solid
- Water solubility: The water solubility of 2,6-di-tert-butylphenol is 4.11 mg/L at 25 °C at pH 7 determined with a method equivalent or similar to OECD Guideline 105 (Water Solubility)

Sampling and analysis

Analytical monitoring:
no
Details on sampling:
None

Test substrate

Vehicle:
yes
Remarks:
Quartz sand
Details on preparation and application of test substrate:
The control and test item treatments were applied once at the beginning of the study. The respective test item amount was weighed out for each test item concentration and blended thoroughly with quartz sand (1 % of the entire soil amount per concentration). Afterwards the test item - quartz sand mixture and an appropriate amount of demineralised water (adjusting the soil to a moisture of 50 % of the maximum water holding capacity (MWHC)) were added to the soil. Subsequently, the soil was mixed carefully with a mixer (3 min) to ensure a homogeneous distribution.
Due to large soil amounts per concentration, four batches of 7.2 kg soil dry weight were prepared per concentration and applied separately (total soil amount per concentration and control: 28.8 kg soil dry weight).
The treated soil was transferred to the test container and the seeds were sown.

Test organisms

open allclose all
Species:
Avena sativa
Plant group:
Monocotyledonae (monocots)
Details on test organisms:
- Common name: Oats
- Plant family: Poaceae
- Variety: KWS Contender
- Source of seed: KWS Lochow GmbH, 29303 Bergen, Germany
- Prior seed treatment / sterilization: No
- Seed storage: The seeds were stored dark at the test facility at room temperature (22 ± 10 °C) and protected from moisture until use.
Species:
Allium cepa
Plant group:
Monocotyledonae (monocots)
Details on test organisms:
- Common name: Onion
- Plant family: Amaryllidaceae
- Variety: Exhibition
- Source of seed: Hild Samen GmbH, 71666 Marbach, Germany
- Prior seed treatment / sterilization: No
- Seed storage: The seeds were stored dark at the test facility at room temperature (22 ± 10 °C) and protected from moisture until use.
Species:
Beta vulgaris
Plant group:
Dicotyledonae (dicots)
Details on test organisms:
- Common name: Sugar beet
- Plant family: Amaranthaceae
- Variety: Finola KWS
- Source of seed: KWS Saat SE, 37574 Einbeck, Germany
- Prior seed treatment / sterilization: No
- Seed storage: The seeds were stored dark at the test facility at room temperature (22 ± 10 °C) and protected from moisture until use.
Species:
Brassica napus
Plant group:
Dicotyledonae (dicots)
Details on test organisms:
- Common name: Rape
- Plant family: Brassicaceae
- Variety: Sherlock
- Source of seed: KWS Saat SE, 37574 Einbeck, Germany
- Prior seed treatment / sterilization: No
- Seed storage: The seeds were stored dark at the test facility at room temperature (22 ± 10 °C) and protected from moisture until use.
Species:
Lactuca sativa
Plant group:
Dicotyledonae (dicots)
Details on test organisms:
- Common name: Lettuce
- Plant family: Asteraceae
- Variety: Mafalda
- Source of seed: Hild Samen GmbH, 71666 Marbach, Germany
- Prior seed treatment / sterilization: No
- Seed storage: The seeds were stored dark at the test facility at room temperature (22 ± 10 °C) and protected from moisture until use.
Species:
Glycine max (G. soja)
Plant group:
Dicotyledonae (dicots)
Details on test organisms:
- Common name: Soybean
- Plant family: Fabaceae
- Variety: Tourmaline
- Source of seed: Farmsaat AG, 48351 Everswinkel, Germany
- Prior seed treatment / sterilization: No
- Seed storage: The seeds were stored dark at the test facility at room temperature (22 ± 10 °C) and protected from moisture until use.

Study design

Test type:
seedling emergence toxicity test
Study type:
laboratory study
Substrate type:
other: A 2:1 mixture of natural soil LUFA 2.2 (batch number: Sp2.20717, sandy loam (USDA classification)) and quartz sand (12a) was used.
Remarks:
Grain size: <= 2 mm Clay (< 0.002 mm): 6.2 % Silt (0.002 - 0.063 mm): 9.3 % and (0.063 - 2 mm): 84.5 % Carbon content: 1.17 % pH-value: 6.40 ± 0.05
Limit test:
no
Total exposure duration:
21 d
Remarks:
Onion: 28d

Test conditions

Test temperature:
nominal: 20 +/- 2 °C; actual: 14.7 - 23.9 °C
Moisture:
Relative humidity:
Nominal: 70 25 %; actual: 38.0 - 98.3 %
Details on test conditions:
TEST SYSTEM
- Testing facility: Noack Laboratorien GmbH
- Test container (type, material, size): Non-porous plastic containers (standard flower pots) with a diameter of ca. 12 cm were used. The pots were labelled with the study number and all necessary additional information to ensure unique identification.
- Amount of soil:
Soil amount per test concentration and control:
28.8 kg soil dry weight; 4 batches per concentration and control; 7.2 kg soil dry weight per batch
- Method of seeding: Test containers were filled each with the same amount of treated soil (see application technique) and seeding holes were made with a seedling pistil. One seed was given into each hole and covered with soil.
- No. of seeds per container: 5 seeds per test container (soybean: 3)
- No. of replicates per treatment group: 8 replicates
- No. of replicates per control: 8 replicates

SOURCE AND PROPERTIES OF SUBSTRATE (if soil)
A 2:1 mixture of natural soil LUFA 2.2 (batch number: Sp2.23916) and quartz sand (12a) was used.
Grain size: <= 0.2 mm
Carbon content: 0.943 %
pH-value: 6.14 ± 0.03

NUTRIENT MEDIUM (if used)
- Description:
Fertilizer: HAKAPHOS® SOFT SPEZIAL 16+8+22(+3) (0.5 ‰)
Origin: GRÜNES LANDHAUS, St. Godehard-Str. 23, 31139 Hildesheim, Germany

Nutrient Concentration [%]
Ammonium nitrogen 6.3
Nitrate nitrogen 9.7
P2O5 8
Potassium oxide 22
Magnesium oxide 3
Boron 0.03
Iron (Chelate) 0.15
Copper 0.02
Manganese 0.05
Molybdenum 0.005
Zinc 0.015


GROWTH CONDITIONS
- Photoperiod: 16 h
- Light source: Special-fluorescent tube Fluora and Daylight (OSRAM)
- Light intensity and quality: nominal: > 3500 lx; actual: 4821 ± 445 lx
- Temperatures: 14.7 - 23.9 °C
- Relative humidity (%): 338.0 - 98.3 %

ACCLIMATION PERIOD: None

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
During the 21 - 28 day observation period (from day of application) the plants were observed on day 7, 14 and 21, onion additionally on day 28, for number of emerged seedlings, number of dead plants and visual phytotoxic effects.
The rating of the treated plants was done in relation to the untreated control plants. Observations included all variations, either inhibitory or stimulatory, between the treated replicates and the untreated controls. Such variations may be phytotoxic symptoms (e.g. chlorosis, necrosis, wilting), formative effects of growth and development rates.
At the end of the study the shoot heights (in cm) and the shoot fresh weights of the shoots (in g) were measured additionally, directly after cutting the plants at the soil surface.
The shoot height was measured per plant. Average mean values per replicate were calculated. The shoot fresh weight was determined for all plants from the same pot and considered as one replicate.

- Phytotoxicity rating system (if used):
Observation Parameters
(1) Alteration of form and appearance (deformation)
(1.1) Curling / twisting / sticking or other deformation of the leaves
(1.2) Change of appearance
(1.3) Shoot deformations
(1.4) Wilting
(1.5) Leaf shedding
(1.6) Shedding of the leaf apex
(1.7) Stunted growth
(2) Discolouration of the leaves
(2.1) Lighter green
(2.2) Darker green
(2.3) Chlorosis
(2.3.1) Spots
(2.3.2) Whole leaf
(2.3.3) Veins
(2.3.4) Between veins
(2.3.5) Marginal
(2.4) Loss of colour
(2.5) Discolouration of the leaves
(2.6) Discolouration of the veins
(2.7) Discolouration of the shoot
(3) Alteration of the leaf cells
(3.1) Necrosis
(3.1.1) Spots
(3.1.2) Marginal
(3.1.3) Apical
(3.1.4) Between veins
(3.1.5) Whole leaf
(3.1.6) Veins
(E) Dead plant (Number of dead plants)

Assessment of the Effects
- = no effects observed / normal growth
+/- = slight effects
+ = medium effects
++ = strong effects 

VEHICLE CONTROL PERFORMED: no

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 2.7
- Range finding study

The preliminary study was performed under the same environmental conditions and test duration as the definitive study.

Inhibition of Shoot Fresh Weight
Test concentration
[mg/kg DW] Inhibition [%]
Oats Onion Sugar beet Rape Lettuce Soy-bean
10 6 -1 3 -4 -3 8
100 74 75 81 48 90 9
1000 n.d. n.d. 96 97 95 71

Inhibition of Rate of Emergence
Test concentration
[mg/kg DW] Inhibition [%]
Oats Onion Sugar beet Rape Lettuce Soy-bean
10 5 -12 0 5 0 0
100 26 18 5 0 5 27
1000 100 100 40 11 30 27
Negative values = promoted growth
DW = soil dry weight
n.d. = not determinable, plants not emerged
Nominal and measured concentrations:
Nominal:
1000.00 - 370.37 - 137.17 - 50.81 - 18.82 - 6.97 mg/kg DW (factor 2.7)
Reference substance (positive control):
no

Results and discussion

Effect concentrationsopen allclose all
Species:
Avena sativa
Duration:
21 d
Dose descriptor:
NOEC
Effect conc.:
6.97 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other: shoot fresh weight
Species:
Avena sativa
Duration:
21 d
Dose descriptor:
LOEC
Effect conc.:
18.82 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other: shoot fresh weight
Species:
Avena sativa
Duration:
21 d
Dose descriptor:
EC25
Effect conc.:
23.5 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other: shoot fresh weight
Remarks on result:
other: 19.0 - 28.7
Species:
Avena sativa
Duration:
21 d
Dose descriptor:
EC50
Effect conc.:
55.7 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other: shoot fresh weight
Remarks on result:
other: 47.9 - 64.7
Species:
Avena sativa
Duration:
21 d
Dose descriptor:
NOEC
Effect conc.:
50.81 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other: shoot height
Species:
Avena sativa
Duration:
21 d
Dose descriptor:
LOEC
Effect conc.:
137.17 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other: shoot height
Species:
Avena sativa
Duration:
21 d
Dose descriptor:
EC25
Effect conc.:
109 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other: shoot height
Remarks on result:
other: 100.0 - 120.0
Species:
Avena sativa
Duration:
21 d
Dose descriptor:
EC50
Effect conc.:
> 137.17 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other: shoot height
Species:
Avena sativa
Duration:
21 d
Dose descriptor:
NOEC
Effect conc.:
50.81 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
germination
Species:
Avena sativa
Duration:
21 d
Dose descriptor:
LOEC
Effect conc.:
137.17 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
germination
Species:
Avena sativa
Duration:
21 d
Dose descriptor:
EC25
Effect conc.:
128 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
germination
Remarks on result:
other: 105.0 - 153.0
Species:
Avena sativa
Duration:
21 d
Dose descriptor:
EC50
Effect conc.:
192 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
germination
Remarks on result:
other: 165.0 - 231.0
Species:
Allium cepa
Duration:
28 d
Dose descriptor:
NOEC
Effect conc.:
50.81 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other: shoot fresh weight
Species:
Allium cepa
Duration:
28 d
Dose descriptor:
LOEC
Effect conc.:
137.17 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other: shoot fresh weight
Species:
Allium cepa
Duration:
28 d
Dose descriptor:
EC25
Effect conc.:
55.6 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other:
Remarks:
shoot fresh weight
Remarks on result:
other: 46.9 - 83.2
Species:
Allium cepa
Duration:
28 d
Dose descriptor:
EC50
Effect conc.:
71.1 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other:
Remarks:
shoot fresh weight
Remarks on result:
other: 59.0 - 101.0
Species:
Allium cepa
Duration:
28 d
Dose descriptor:
NOEC
Effect conc.:
50.81 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other: shoot height
Species:
Allium cepa
Duration:
28 d
Dose descriptor:
LOEC
Effect conc.:
137.17 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other: shoot height
Species:
Allium cepa
Duration:
28 d
Dose descriptor:
EC25
Effect conc.:
65.1 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other: shoot height
Remarks on result:
other: 56.0 - 82.0
Species:
Allium cepa
Duration:
28 d
Dose descriptor:
EC50
Effect conc.:
80.2 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other: shoot height
Remarks on result:
other: 66.7 - 95.9
Species:
Allium cepa
Duration:
28 d
Dose descriptor:
NOEC
Effect conc.:
137.17 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
germination
Species:
Allium cepa
Duration:
28 d
Dose descriptor:
LOEC
Effect conc.:
370.37 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
germination
Species:
Allium cepa
Duration:
28 d
Dose descriptor:
EC25
Effect conc.:
256 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
germination
Remarks on result:
other: 189.0 - 329.0
Species:
Allium cepa
Duration:
28 d
Dose descriptor:
EC50
Effect conc.:
438 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
germination
Remarks on result:
other: 351.0 - 555.0
Species:
Beta vulgaris
Duration:
21 d
Dose descriptor:
NOEC
Effect conc.:
18.82 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other: shoot fresh weight
Species:
Beta vulgaris
Duration:
21 d
Dose descriptor:
LOEC
Effect conc.:
50.81 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other: shoot fresh weight
Species:
Beta vulgaris
Duration:
21 d
Dose descriptor:
EC25
Effect conc.:
25.8 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other: shoot fresh weight
Remarks on result:
other: 19.9 - 32.8
Species:
Beta vulgaris
Duration:
21 d
Dose descriptor:
EC50
Effect conc.:
43.5 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other: shoot fresh weight
Remarks on result:
other: 37.0 - 49.0
Species:
Beta vulgaris
Duration:
21 d
Dose descriptor:
NOEC
Effect conc.:
18.82 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other: shoot height
Species:
Beta vulgaris
Duration:
21 d
Dose descriptor:
LOEC
Effect conc.:
50.81 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other: shoot height
Species:
Beta vulgaris
Duration:
21 d
Dose descriptor:
EC25
Effect conc.:
40.7 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other: shoot height
Remarks on result:
other: 36.3 - 45.3
Species:
Beta vulgaris
Duration:
21 d
Dose descriptor:
EC50
Effect conc.:
87.2 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other: shoot height
Remarks on result:
other: 79.7 - 96.1
Species:
Beta 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:
germination
Species:
Beta vulgaris
Duration:
21 d
Dose descriptor:
LOEC
Effect conc.:
> 1 000 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
germination
Species:
Brassica napus
Duration:
21 d
Dose descriptor:
NOEC
Effect conc.:
18.82 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other: shoot fresh weight
Species:
Brassica napus
Duration:
21 d
Dose descriptor:
LOEC
Effect conc.:
50.81 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other: shoot fresh weight
Species:
Brassica napus
Duration:
21 d
Dose descriptor:
EC25
Effect conc.:
47 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other: shoot fresh weight
Remarks on result:
other: 40.3 - 54.5
Species:
Brassica napus
Duration:
21 d
Dose descriptor:
EC50
Effect conc.:
83.8 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other: shoot fresh weight
Remarks on result:
other: 75.3 - 93.0
Species:
Brassica napus
Duration:
21 d
Dose descriptor:
NOEC
Effect conc.:
18.82 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other: shoot height
Species:
Brassica napus
Duration:
21 d
Dose descriptor:
LOEC
Effect conc.:
50.81 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other: shoot height
Species:
Brassica napus
Duration:
21 d
Dose descriptor:
EC25
Effect conc.:
92.8 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other: shoot height
Remarks on result:
other: 83.5 - 102.0
Species:
Brassica napus
Duration:
21 d
Dose descriptor:
EC50
Effect conc.:
190 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other: shoot height
Remarks on result:
other: 175.0 - 208.0
Species:
Brassica napus
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:
germination
Species:
Brassica napus
Duration:
21 d
Dose descriptor:
LOEC
Effect conc.:
> 1 000 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
germination
Species:
Lactuca sativa
Duration:
21 d
Dose descriptor:
NOEC
Effect conc.:
18.82 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other: shoot fresh weight
Species:
Lactuca sativa
Duration:
21 d
Dose descriptor:
LOEC
Effect conc.:
50.81 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other: shoot fresh weight
Species:
Lactuca sativa
Duration:
21 d
Dose descriptor:
EC25
Effect conc.:
20.6 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other: shoot fresh weight
Remarks on result:
other: 15.9 - 27.4
Species:
Lactuca sativa
Duration:
21 d
Dose descriptor:
EC50
Effect conc.:
32.3 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other: shoot fresh weight
Remarks on result:
other: 26.2 - 38.3
Species:
Lactuca sativa
Duration:
21 d
Dose descriptor:
NOEC
Effect conc.:
18.82 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other: shoot height
Species:
Lactuca sativa
Duration:
21 d
Dose descriptor:
LOEC
Effect conc.:
50.81 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other: shoot height
Species:
Lactuca sativa
Duration:
21 d
Dose descriptor:
EC25
Effect conc.:
28.9 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other: shoot height
Remarks on result:
other: 24.5 - 33.5
Species:
Lactuca sativa
Duration:
21 d
Dose descriptor:
EC50
Effect conc.:
48.6 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other: shoot height
Remarks on result:
other: 44.8 - 52.5
Species:
Lactuca sativa
Duration:
21 d
Dose descriptor:
NOEC
Effect conc.:
137.17 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
germination
Species:
Lactuca sativa
Duration:
21 d
Dose descriptor:
LOEC
Effect conc.:
370.37 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
germination
Species:
Lactuca sativa
Duration:
21 d
Dose descriptor:
EC25
Effect conc.:
483 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
germination
Remarks on result:
other: 208 - > 1000
Species:
Lactuca sativa
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:
germination
Species:
Glycine max (G. soja)
Duration:
21 d
Dose descriptor:
NOEC
Effect conc.:
50.81 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other: shoot fresh weight
Species:
Glycine max (G. soja)
Duration:
21 d
Dose descriptor:
LOEC
Effect conc.:
137.17 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other: shoot fresh weight
Species:
Glycine max (G. soja)
Duration:
21 d
Dose descriptor:
EC25
Effect conc.:
147 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other: shoot fresh weight
Remarks on result:
other: 105.0 - 195.0
Species:
Glycine max (G. soja)
Duration:
21 d
Dose descriptor:
EC50
Effect conc.:
286 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other: shoot fresh weight
Remarks on result:
other: 215.0 - 401.0
Species:
Glycine max (G. soja)
Duration:
21 d
Dose descriptor:
NOEC
Effect conc.:
137.17 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other: shoot height
Species:
Glycine max (G. soja)
Duration:
21 d
Dose descriptor:
LOEC
Effect conc.:
370.37 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other: shoot height
Species:
Glycine max (G. soja)
Duration:
21 d
Dose descriptor:
EC25
Effect conc.:
252 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other: shoot height
Remarks on result:
other: 196.0 - 315.0
Species:
Glycine max (G. soja)
Duration:
21 d
Dose descriptor:
EC50
Effect conc.:
449 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other: shoot height
Remarks on result:
other: 378.0 - 531.0
Species:
Glycine max (G. soja)
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:
germination
Species:
Glycine max (G. soja)
Duration:
21 d
Dose descriptor:
LOEC
Effect conc.:
> 1 000 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
germination
Details on results:
The percentage of inhibition of shoot height, shoot fresh weight and rate of emergence is stated below. Test item-related statistically significant inhibitions are given in bold. Application rates with > 70 % mortality were marked with #. The cut-off values of 70 % mortality is based on experience. At least 30 % surviving plants are necessary for reliable calculations. Application rates with no emerged seedlings were marked with ##. The tabulated results represent rounded mean values calculated on the exact raw data.

Oats: Inhibition [%] of Shoot Height, Shoot Fresh Weight and Rate of Emergence
Test concentration
[mg/kg DW] Shoot
height
[cm] Inhibition

[%] Shoot fresh weight
[mg] Inhibition

[%] Rate of emergence
[%] Inhibition

[%]
Control 38.7 - 1206 - 95 -
6.97 38.3 1 1169 3 95 0
18.82 37.4 3 974 19 85 11
50.81 37.0 4 632 48 93 2
137.17 23.3 40 275 77 68 28
370.37 (1.3)# (97) 11 99 13 86
1000.00 ## - ## - 0 100


Onion: Inhibition [%] of Shoot Height, Shoot Fresh Weight and Rate of Emergence
Test concentration
[mg/kg DW] Shoot
height
[cm] Inhibition

[%] Shoot fresh weight
[mg] Inhibition

[%] Rate of emergence
[%] Inhibition

[%]
Control 16.6 - 235 - 88 -
6.97 17.1 -3 233 1 95 -8
18.82 15.7 5 213 9 90 -2
50.81 15.2 8 191 19 88 0
137.17 1.8 89 11 95 88 0
370.37 1.2 93 3 99 48 45
1000.00 1.0 94 5 98 18 80
negative values = promoted growth
bold = statistically significant inhibition
()# = > 70 % mortality, not included in statistical calculations
## = No plants emerged.
 
Sugar Beet: Inhibition [%] of Shoot Height, Shoot Fresh Weight and Rate of Emergence
Test concentration
[mg/kg DW] Shoot
height
[cm] Inhibition

[%] Shoot fresh weight
[mg] Inhibition

[%] Rate of emergence
[%] Inhibition

[%]
Control 10.4 - 1033 - 98 -
6.97 9.8 6 916 11 100 -2
18.82 9.2 12 860 17 93 5
50.81 7.2 31 420 59 100 -2
137.17 3.9 63 94 91 98 0
370.37 2.5 76 43 96 93 5
1000.00 2.4 77 43 96 90 8


Rape: Inhibition [%] of Shoot Height, Shoot Fresh Weight and Rate of Emergence
Test concentration
[mg/kg DW] Shoot
height
[cm] Inhibition

[%] Shoot fresh weight
[mg] Inhibition

[%] Rate of emergence
[%] Inhibition

[%]
Control 17.0 - 1614 - 100 -
6.97 17.2 -1 1460 10 95 5
18.82 16.9 1 1502 7 98 2
50.81 15.2 11 1153 29 93 7
137.17 10.5 38 439 73 98 2
370.37 5.0 71 125 92 95 5
1000.00 2.5 85 47 97 95 5
negative values = promoted growth
bold = statistically significant inhibition

 
Lettuce: Inhibition [%] of Shoot Height, Shoot Fresh Weight and Rate of Emergence
Test concentration
[mg/kg DW] Shoot
height
[cm] Inhibition

[%] Shoot fresh weight
[mg] Inhibition

[%] Rate of emergence
[%] Inhibition

[%]
Control 7.7 - 689 - 100 -
6.97 7.0 9 603 12 100 0
18.82 6.6 14 539 22 98 2
50.81 3.7 52 148 79 100 0
137.17 1.4 82 41 94 93 7
370.37 1.1 86 26 96 78 22
1000.00 1.1 86 21 97 73 27


Soybean: Inhibition [%] of Shoot Height, Shoot Fresh Weight and Rate of Emergence
Test concentration
[mg/kg DW] Shoot
height
[cm] Inhibition

[%] Shoot fresh weight
[mg] Inhibition

[%] Rate of emergence
[%] Inhibition

[%]
Control 25.3 - 2638 - 100 -
6.97 25.0 1 2590 2 100 0
18.82 24.4 4 2690 -2 79 21
50.81 22.8 10 2569 3 88 12
137.17 23.5 7 2021 23 88 12
370.37 14.6 42 1116 58 75 25
1000.00 4.5 82 698 74 75 25
negative values = promoted growth
bold = statistically significant inhibition
Results with reference substance (positive control):
No reference substance was tested.
Reported statistics and error estimates:
Percentage of inhibition
The percentage of inhibition of biomass growth (shoot height, shoot fresh weight) and rate of emergence were calculated in relation to the control.
All dead plants were weighed and observed and included in the calculation. No shoot height determination of dead plants was carried out. 
NOEC / LOEC of biomass growth / emergence
One Way Analysis of Variance (ANOVA) was carried out for the determination of statistically significant differences compared to control replicates. When running a One Way Analysis of Variance, a Normality test and an Equal Variance test were done first. P-values for both, Normality and Equal Variance test, are 0.05. The alpha-value for ANOVA (acceptable probability of incorrectly concluding that there is a difference) is alpha = 0.05.
In case of failure of the normality test or the equal variance test a Kruskal-Wallis One Way Analysis of Ranks and Dunnett’s and Dunn’s test, respectively, were carried out.
EC-values and confidence intervals of biomass growth
EC25- and EC50- values were calculated by sigmoidal dose-response regression using GraphPadPrism. Calculation of the confidence intervals for EC-values was carried out using standard procedures.
Software
The data for the tables in the report were computer generated and rounded for presentation from the fully derived data. Consequently, if calculated manually based on the given data, minor deviations may occur from these figures.
Excel, Microsoft Corporation
SigmaPlot (Windows), SPSS Incorporation
GraphPadPrism, GraphPad Software, Inc

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
Potential toxic effects of the test item were assessed on day 7, 14 and 21 (onion additionally day 28) by visual observations (number of emerged seedlings and phytotoxic effects) and at test end by shoot height and shoot fresh weight determination.
The NOEC and LOEC values, as well as the EC-values with confidence ranges, are gstated below.

Shoot Height: NOEC, LOEC, EC25- and EC50-Values with Confidence Range (p)
Species NOEC
[mg/kg DW] LOEC
[mg/kg DW] EC25
[mg/kg DW] p = 95%
[mg/kg DW] EC50
[mg/kg DW] p = 95%
[mg/kg DW]
Oats 50.81 137.17 109 100 - 120 > 137.17# –
Onion 50.81 137.17 65.1 56.0 - 82.0 80.2 66.7 - 95.9
Sugar beet 18.82 50.81 40.7 36.3 - 45.3 87.2 79.7 - 96.1
Rape 18.82 50.81 92.8 83.5 - 102 190 175 - 208
Lettuce 18.82 50.81 28.9 24.5 - 33.5 48.6 44.8 - 52.5
Soybean 137.17 370.37 252 196 - 315 449 378 - 531
-) Not determinable
#) For higher tested application rates > 70 % mortality occurred and were not included in statistical calculations.

Shoot Fresh Weight: NOEC, LOEC, EC25- and EC50-Values with Confidence Range (p)
Species NOEC
[mg/kg DW] LOEC
[mg/kg DW] EC25
[mg/kg DW] p = 95%
[mg/kg DW] EC50
[mg/kg DW] p = 95%
[mg/kg DW]
Oats 6.97 18.82 23.5 19.0 - 28.7 55.7 47.9 - 64.7
Onion 50.81 137.17 55.6 46.9 - 83.2 71.1 59.0 - 101
Sugar beet 18.82 50.81 25.8 19.9 - 32.8 43.5 37.0 - 49.0
Rape 18.82 50.81 47.0 40.3 - 54.5 83.8 75.3 - 93.0
Lettuce 18.82 50.81 20.6 15.9 - 27.4 32.3 26.2 - 38.3
Soybean 50.81 137.17 147 105 - 195 286 215 - 401

Number of Emerged Seedlings: NOEC, LOEC, EC25- and EC50-Values with Confidence Range (p)
Species NOEC
[mg/kg DW] LOEC
[mg/kg DW] EC25
[mg/kg DW] p = 95%
[mg/kg DW] EC50
[mg/kg DW] p = 95%
[mg/kg DW]
Oats 50.81 137.17 128 105 - 153 192 165 - 231
Onion 137.17 370.37 256 189 - 329 438 351 - 555
Sugar beet 1000 > 1000 > 1000 – > 1000 –
Rape 1000 > 1000 > 1000 – > 1000 –
Lettuce 137.17 370.37 483 208 - > 1000 > 1000 –
Soybean 1000 > 1000 > 1000 – > 1000 –
-) Not determinable
Executive summary:

The phytotoxicity of the test item 2,6-DI-TERT-BUTYLPHENOL HIGHPURITY (batch number: 222428901) to six terrestrial plant species was determined according to OECD 208 (July 2006) at the test facility in a seedling emergence and seedling growth test over a period of 21 days, from 2017-04-26 to 2017-05-17. For onion 50 % emergence of the control seedlings was observed after 14 days. Therefore, the test for onion was prolonged until day 28 (2017-05-24).

 

Test Design

Test systems comprised two monocotyledons (oats, Poaceae; onion, Amaryllidaceae), and four dicotyledons (sugar beet, Amaranthaceae; rape, Brassicaceae; lettuce, Asteraceae; soybean, Fabaceae).

The test was conducted with the test concentrations of 1000.00 - 370.37 - 137.17 - 50.81 -18.82 - 6.97 mg/kg DW (factor 2.7).

The test item was incorporated into the soil in which the seeds were sown after. The test containers were bottom watered with nutrient solution as needed.

 

Results

Potential toxic effects of the test item were assessedon day 7, 14 and 21 (onion additionally on day 28) by visual observations (number of emerged seedlings and phytotoxic effects) and at test end by shoot height and shoot fresh weight determination.

No test item related phytotoxic effects and mortality occurred during the test period for all plant species.

 

The results in terms of shoot height (in cm) and biomass (in g) at test end are presented below.

The statistically calculated NOEC and LOEC values, as well as the EC25- and EC50-values, are summarized below.

 

The results of the control for all plant species met the required validity criteria. Therefore, the test is considered to be valid.


 

Shoot Height: NOEC, LOEC, EC25- and EC50-Values with Confidence Range (p)

Species

NOEC
[mg/kg DW]

LOEC
[mg/kg DW]

EC25
[mg/kg DW]

p = 95%
[mg/kg DW]

EC50
[mg/kg DW]

p = 95%
[mg/kg DW]

Oats

50.81

137.17

109

100 - 120

> 137.17#

–

Onion

50.81

137.17

  65.1

56.0 - 82.0

     80.2

66.7 - 95.9

Sugar beet

18.82

50.81

  40.7

36.3 - 45.3

     87.2

79.7 - 96.1

Rape

18.82

50.81

  92.8

83.5 - 102

   190

175 - 208

Lettuce

18.82

50.81

  28.9

24.5 - 33.5

     48.6

44.8 - 52.5

Soybean

137.17

370.37

252

196 - 315

   449

378 - 531

 

 

Shoot Fresh Weight: NOEC, LOEC, EC25- and EC50-Values with Confidence Range (p)

Species

NOEC
[mg/kg DW]

LOEC
[mg/kg DW]

EC25
[mg/kg DW]

p = 95%
[mg/kg DW]

EC50
[mg/kg DW]

p = 95%
[mg/kg DW]

Oats

6.97

18.82

  23.5

19.0 - 28.7

  55.7

47.9 - 64.7

Onion

50.81

137.17

55.6

46.9 - 83.2

  71.1

59.0 - 101

Sugar beet

18.82

50.81

  25.8

19.9 - 32.8

  43.5

37.0 - 49.0

Rape

18.82

50.81

  47.0

40.3 - 54.5

  83.8

75.3 - 93.0

Lettuce

18.82

50.81

  20.6

15.9 - 27.4

  32.3

26.2 - 38.3

Soybean

50.81

137.17

147

105 - 195

286

215 - 401

Number of Emerged Seedlings: NOEC, LOEC, EC25- and EC50-Values with Confidence Range (p)

Species

NOEC
[mg/kg DW]

LOEC
[mg/kg DW]

EC25
[mg/kg DW]

p = 95%
[mg/kg DW]

EC50
[mg/kg DW]

p = 95%
[mg/kg DW]

Oats

50.81

137.17

     128

105 - 153

     192

165 - 231

Onion

137.17

370.37

     256

189 - 329

     438

351 - 555

Sugar beet

1000    

> 1000     

> 1000

–

> 1000

–

Rape

1000    

> 1000     

> 1000

–

> 1000

–

Lettuce

137.17

370.37

     483

208 - > 1000

> 1000

–

Soybean

1000    

> 1000     

> 1000

–

> 1000

–

-) Not determinable
#) For higher tested application rates > 70 % mortality occurred and were not included in statistical calculations.