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Toxicity to terrestrial plants

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Reference
Endpoint:
toxicity to terrestrial plants: short-term
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Study period:
August 25, 2015 to March 17, 2016
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Guideline study, which is rated as reliability 2 because it is a read-across study.
Justification for type of information:
Please refer to IUCLID Section 13 for the read-across justification.
Reason / purpose:
read-across source
Qualifier:
according to
Guideline:
OECD Guideline 208 (Terrestrial Plants Test: Seedling Emergence and Seedling Growth Test)
Deviations:
no
GLP compliance:
yes
Specific details on test material used for the study:
Details on properties of test surrogate or analogue material (migrated information):None specified
Analytical monitoring:
yes
Details on sampling:
After preparation of dosing stocks, 10 mL samples were collected to verify test concentration and to demonstrate homogeneity of the test substance in the dosing solutions. A single sample was collected from the negative control, the solvent control, and the lower four test level dosing stocks.Triplicate samples were collected from the high level dosing stock. Following collection, samples were transferred to the analytical chemistry laboratory for analysis.
Vehicle:
yes
Details on preparation and application of test substrate:
Test Soil

The soil used for the test was characterized as a loamy sand soil, and was a mixture of kaolinite clay, industrial quartz sand, and peat, with limestone to buffer the soil pH. A slow-release fertilizer was added to provide nutrients essential for plant growth. A sample of the soil representative of that used in this study was sent to Agvise Laboratories, Inc., in Northwood, North Dakota, for analysis of the particle size distribution and organic matter content of the soil. The soil was determined to consist of 85% sand, 6% silt, and 9% clay, with an organic matter content of 1.8% (1% organic carbon). The soil pH was measured to be 6.4 (1:1 soil:water ratio). Soil moisture was determined by Wildlife International to be 6%. The complete report from Agvise Laboratories, Inc. was filed in the archives at Wildlife International along with the raw data for this study.

Preparation and Soil Incorporation of the Test Substance

Test soils were prepared by mixing stock solutions of the test substance into 120 kg fresh weight of soil. A primary stock was prepared by adding 228.3 g of the test substance to 2000 mL of acetonitrile and mixing by swirling, sonication, inversion and stirring. The primary stock concentration was based on a mean, measured soil moisture content of 6%, and a volume of 990 mL to be used for soil preparation. Secondary stocks were prepared by diluting 62.5, 125, 250 and 500 mL aliquots of the primary stock, each to a final volume of 1000 mL with acetonitrile, and mixing by stirring and sonicating. The solvent control stock consisted of acetonitrile only, and the negative control stock consisted of well water purified by reverse osmosis. In order to prepare test soils, 990 mL of each stock was added to 120 kg of bulk soil, mixed in a soil mixer for approximately 10 minutes, turned by hand, and then mixed for another approximate 10 minute period. The negative control was prepared first, followed by the solvent control and then the test soils in order of increasing concentration to avoid cross-contamination of the test material.
Species:
Lycopersicon esculentum
Plant group:
Dicotyledonae (dicots)
Details on test organisms:
- Common name: tomato- Plant family: Solanaceae- Variety: Rutgers- Source of seed: The Meyer Seed Co., Baltimore, MD, USA- Historical germination of seed (germination of seed lot tested): 90%
Species:
Lactuca sativa
Plant group:
Dicotyledonae (dicots)
Details on test organisms:
- Common name: lettuce- Plant family: Asteraceae- Variety: Summertime- Source of seed: Sustainable Seed Co., Covelo, CA, USA- Historical germination of seed (germination of seed lot tested): 98%
Species:
Glycine max (G. soja)
Plant group:
Dicotyledonae (dicots)
Details on test organisms:
- Common name: Soy bean- Plant family: Fabaceae- Variety: Viking 2265- Source of seed: Johnny's Selected Seeds, Winslow, ME, USA- Historical germination of seed (germination of seed lot tested): 88%
Species:
Brassica napus
Plant group:
Dicotyledonae (dicots)
Details on test organisms:
- Common name: Oil seed rape- Plant family: Brassicaceae- Variety: Dwarf Essex- Source of seed: Johnny's Selected Seeds, Winslow, ME, USA- Historical germination of seed (germination of seed lot tested): 96%
Species:
Zea mays
Plant group:
Monocotyledonae (monocots)
Details on test organisms:
- Common name: Corn- Plant family: Poaceae- Variety: Nothstine Dent OG- Source of seed: Johnnys Selected Seeds, WInslow, ME, USA- Historical germination of seed (germination of seed lot tested): 98%
Species:
Avena sativa
Plant group:
Monocotyledonae (monocots)
Details on test organisms:
- Common name: oat- Plant family: Poaceae- Variety: Saber- Source of seed: Powell Seeds Inc., Converse, IN, USA- Historical germination of seed (germination of seed lot tested): 90%
Test type:
seedling emergence toxicity test
Study type:
laboratory study
Substrate type:
natural soil
Limit test:
no
Total exposure duration:
21 d
Remarks:
following planting (22 days for tomato)
Post exposure observation period:
No post exposure observation period specified.
Test temperature:
Min: 12.76 °C Max: 28.08 °C Mean: 18.94 °C
pH:
The soil pH was measured to be 6.4.
Moisture:
Min: 10.99% Max: 89.40% Mean: 41.40%
Details on test conditions:
EXPERIMENTAL DESIGN

The experimental design consisted of seven test groups (five treatment groups, a negative control and a solvent control) for each test species. All test groups contained eight replicates, each consisting of one pot containing five planted seeds of one species. Test concentrations were selected based on preliminary rangefinder testing results. Soils with target nominal test substance concentrations of 63, 125, 250, 500 and 1000 milligrams test substance per kilogram of soil dry weight (mg/kg) were prepared by incorporating solutions of the test substance in acetonitrile. Well water purified by reverse osmosis was incorporated into soil for the negative control group and acetonitrile was used for the solvent control. Seeds were impartially assigned to pre-labeled growth pots and planted on the day of test initiation. After planting, the replicate pots were arranged according to a randomized complete block design on greenhouse tables after planting. The in-life test duration was a total of 21 days (22 days for tomato). Observations documenting seedling emergence were made on Days 7, 14 and 21 (Days 7, 8, 15, and 22 for tomato), while observations of height and condition were made on test termination. Dry weights were determined from seedling shoots collected at test termination.

Test Species
The species were chosen because they are economically important, readily cultivated test organisms widely used in research. Seeds were selected from a similar size class within each species to reduce the potential for bias from differing seed sizes. Seeds used in this study were not treated with fungicides, insecticides or repellents prior to test initiation.Planting of SeedsSeeds were planted in plastic pots (approximately 16 cm in diameter and 12 cm deep, 1940 cm3 soil volume) on the day of test substance incorporation. Soil was added to the pots and a template was used to indent the soil and leave five uniform holes for planting. One indiscriminately selected seed was then planted in each hole, for a total of five seeds in each pot. Holes were then closed by depressing the soil surface. The seeds for A. sativa, Z. mays and G. max were planted at an approximate depth of 20 mm while the seeds for all other species were planted at an approximate depth of 10 mm. Each pot was labeled with the project number, species name, treatment group, and replicate.

Watering of Seedlings
After the initial top-watering, water for seedling growth was supplied by sub-irrigation with well water from the greenhouse facility. Seedlings were sub-irrigated to minimize the potential for the leaching of the test substance through the soil and out of the root zone. Sub-irrigation trays were filled to a predetermined depth to standardize the amount of water delivered to each tray.

Environmental Conditions
The temperature within the greenhouse was controlled with a Wadsworth MicroStep S/A Environmental Control System. Artificial lighting (high pressure sodium) was used to supplement natural sunlight providing a minimum 16-hour photoperiod. The light intensity, temperature, and relative humidity within the greenhouse were continuously monitored during the test with a Campbell CR-10 datalogger.

Pesticide and Metal Screening of Well Water and Soil
The well water and soil used for plant studies are periodically screened for pesticides and metals. No analytes were measured at levels that were expected to have an impact on the study.Observations and MeasurementsObservations documenting seedling emergence were made on Days 7, 14 and 21 after planting. Since tomato did not achieve 50% emergence by Day 7, tomato emergence was observed each day until 50% or more seeds emerged, which occurred on Day 8. This moved Day 14 and Day 21 observations for tomato to Day 15 and Day 22. Observations on Day 21 (Day 22 for tomato) also consisted of assessing effects on seedling growth and condition. Observations for emergence consisted of determining the number of emerged seedlings within each replicate. 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 leaf curl, lodging and necrosis. Each emerged seedling was assigned a numerical score on a scale of 0 to 100 that described the plant condition. A score of 0 indicated that no effect was observed, and a score of 100 indicated plant mortality. Intermediate scores described the severity of conditions that were observed on living seedlings, where an increase in score described a condition of greater detriment. While scores provided numeric data, conditional ratings were derived from subjective and qualitative assessments of phytotoxicity. Survival was calculated based on the number of emerged seeds that were living at test termination.The growth of emerged seedlings was evaluated by assessing the height of seedlings and the total dry weight of living seedlings within replicates at test termination. The height of each living seedling was measured with a ruler to the nearest whole centimeter from the surface of the soil to the tip of the tallest leaf for A. sativa, Z. mays, B. napus and L. sativa and from the surface of the soil to the apical meristem for G. max and L. esculentum. Following height measurements and seedling assessments at test termination, all living seedlings were clipped at soil level placed in a labelled paper container, dried in an oven, and weighed as a group. Mean seedling dry weight was determined by dividing the total replicate weight by the number of seedlings weighed in each replicate.
Nominal and measured concentrations:
NOMINAL TEST LEVELS: 0 (Negative Control), Solvent Control (acetonitrile), 63, 125, 250, 500 and 1000 mg /kg (milligrams of test substance per kilogram of dry soil)
Reference substance (positive control):
no
Remarks:
solvent control used (acetonitrile)
Species:
Avena sativa
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: Seedling emergence and early growth
Species:
Zea mays
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: Seedling emergence and early growth
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:
other: Seedling emergence and early growth
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:
other: Seedling emergence and early growth
Species:
Lactuca sativa
Duration:
21 d
Dose descriptor:
NOEC
Effect conc.:
125 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other: seedling height
Species:
Lactuca sativa
Duration:
21 d
Dose descriptor:
LOEC
Effect conc.:
250 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other: seedling height
Species:
Lycopersicon esculentum
Duration:
21 d
Dose descriptor:
NOEC
Effect conc.:
63 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other: seedling height and dry weight
Species:
Lycopersicon esculentum
Duration:
21 d
Dose descriptor:
LOEC
Effect conc.:
125 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other: seedling height and dry weight
Details on results:
Validity of the Test

The test was considered valid based on the following criteria in the controls:

1) Emergence was at least 70% for each species

2) Survival was at least 90% for each species,

and

3) No phytotoxic effects other than normal variation in growth and morphology were present.

The above criteria were met in the negative control and solvent control groups of the six species tested. Occasional incidental mortalities may be expected and are observable in plants growing under natural conditions. Therefore, the negative control and solvent control plants were considered to be normal and suitable for comparison to treatment group plants.

Analytical Verification of Test Solutions
Analysis of the control samples did not show any indication of the presence of the test substance or of the presence of a co-eluting substance at the characteristic retention time of the test substance. Matrix fortification samples were prepared at 6500 and 120000 ppm in acetonitrile to determine the method procedural recovery. Measured concentrations in test samples ranged from 75% to 98% of nominal.

Biological Results
There were no significant differences detected between the negative control and the solvent control for any endpoint; therefore, negative and solvent controls were pooled for comparison to the treatment group means. There were no adverse effects on seedling emergence and/or early growth in four of the six test species (A. sativa, Z. mays, B. napus, G. max). While the difference between the pooled control and the 125 mg/kg dry soil level for G. max emergence is statistically significant, it was determined to be incidental to the treatment, as no other treatment levels had an effect. Adverse, treatment-related effects on plant height of Lactuca sativa (lettuce) were observed at the test concentrations of 250 mg/kg and higher. Although mean height of the 500 mg/kg group was not significantly different from the mean of the pooled controls, the reduction was noticeable (19%), and reductions in mean heights of the 1000 and the 250 mg/kg groups were significant (p<0.05).

There were also substantial reductions in the mean weight of L. sativa plants in the 250 and 1000 mg/kg treatment groups. Although these reductions were not statistically significant (p>0.05), they were consistent with the significant reductions in height, and appeared to be treatment-related. The lack of statistical significance was attributed to high variance in the weight data. Adverse, treatment-related effects were also observed on plant height and dry weight of Lycopersicon esculentum (tomato) at the test concentrations of 125 mg/kg and higher. Although they were not significantly different from the mean of the pooled controls, reductions in mean height (19%) and dry weight (31%) of the 500 mg/kg group were noticeable, and observed reductions in mean heights and dry weights of the 1000 and the 250 mg/kg groups were significant (p<0.05). Morphological EffectsPhytotoxic symptoms were slight but evident in the highest treatment levels for L. sativa and L. esculentum. Symptoms typically included chlorosis, necrosis and leaf curl and appeared in a dose-responsive pattern. Therefore, they were attributed to the treatment.
Results with reference substance (positive control):
Reference substance not utilised in this study.
Reported statistics and error estimates:
Negative and solvent control means were compared with a t-test in order to assess potential solvent effects. If no significant differences between the control groups were detected, the controls were pooled for comparison with the treatment groups. Otherwise, the treatment groups were compared to the control group which provided the more conservative comparison. A one-tailed Dunnett’s test aided in establishment of the LOEC and NOEC by determining which treatment groups differed significantly (p < 0.05) from the appropriate control group. Data were also analyzed for homogeneity of variance and normal distribution. Analyses were performed on data from the test using the Dunnett option of the GLM (general linear model) procedure function of SAS version 9.4. Statistical analyses were not conducted for plant condition because those data are qualitative and subjective and therefore not conducive to quantitative analysis. Whenever parametric assumptions (normality and homogeneity of variance) of the test were not met, the failure to meet the assumptions was noted and the results accepted after expert judgment and due to the robust nature of the Dunnett’s test.

Effects of 4-(1 Methyl-1-Phenylethyl)-N-[4-(1-Methyl-1-Phyenylethyl)Phenyl]Aniline onAvena sativa(Oat) Seedling Emergence, Survival, Dry Weight and Height in a 21-Day Seedling Emergence Test

Treatment Group

(mg/kg dry soil)

Emergence

Mean ± SD

(% Reduction)

Day 21

Survival

Mean ± SD

(% Reduction)

Day 21

Dry Weight (g)

Mean ± SD

(% Reduction)

Day 21

Height (cm)

Mean ± SD

(% Reduction)

Day 21

Pooled Controls

4.4 ± 0.81

95 ± 12.0

0.145 ± 0.0346

31.9 ± 4.42

63

4.5 ± 0.76

(-3%)

98 ± 7.1

(-3%)

0.152 ± 0.0170

(-5%)

32.4 ± 2.18

(-1%)

125

4.5 ± 0.53

(-3%)

100 ± 0

(-6%)

0.168 ± 0.0255

(-16%)

33.0 ± 2.66

(-3%)

250

4.5 ± 0.76

(-3%)

100 ± 0

(-6%)

0.147 ± 0.0225

(-1%)

31.8 ± 3.18

(0%)

500

4.8 ± 0.71

(-9%)

98 ± 7.1

(-3%)

0.154 ± 0.0398

(-6%)

32.3 ± 4.44

(-1%)

1000

4.3 ± 0.46

(3%)

98 ± 7.1

(-3%)

0.163 ± 0.0171

(-12%)

33.7 ± 1.56

(-6%)

Mean ± SD = Mean plus or minus one standard deviation

*Treatment group mean was significantly different from the Pooled Control mean (p<0.05), lack of notation indicates lack of significance

 

Effects of 4-(1 Methyl-1-Phenylethyl)-N-[4-(1-Methyl-1-Phyenylethyl)Phenyl]Aniline onZea mays(Corn) Seedling Emergence, Survival, Dry Weight and Height in a 21-Day Seedling Emergence Test

Treatment Group

(mg/kg dry soil)

Emergence

Mean ± SD

(% Reduction)

Day 21

Survival

Mean ± SD

(% Reduction)

Day 21

Dry Weight (g)

Mean ± SD

(% Reduction)

Day 21

Height (cm)

Mean ± SD

(% Reduction)

Day 21

Pooled Controls

4.6 ± 0.62

100 ± 0

0.314 ± 0.0878

35.4 ± 5.90

63

4.8 ± 0.46

(-3%)

100 ± 0

(0%)

0.367 ± 0.0944

(-17%)

38.1 ± 4.89

(-8%)

125

4.8 ± 0.71

(-3%)

100 ± 0

(0%)

0.338 ± 0.0906

(-8%)

34.6 ± 4.34

(2%)

250

4.6 ± 0.52

(0%)

100 ± 0

(0%)

0.316 ± 0.0917

(-1%)

35.2 ± 6.66

(0%)

500

4.9 ± 0.35

(-5%)

100 ± 0

(0%)

0.322 ± 0.0915

(-3%)

35.8 ± 5.58

(-1%)

1000

4.6 ± 0.52

(0%)

98 ± 7.1

(3%)

0.314 ± 0.0894

(0%)

34.3 ± 4.65

(3%)

Mean ± SD = Mean plus or minus one standard deviation

*Treatment group mean was significantly different from the Pooled Control mean (p<0.05), lack of notation indicates lack of significance

 

Effects of 4-(1 Methyl-1-Phenylethyl)-N-[4-(1-Methyl-1-Phyenylethyl)Phenyl]Aniline onBrassica napus(Oil seed rape) Seedling Emergence, Survival, Dry Weight and Height in a 21-Day Seedling Emergence Test

Treatment Group

(mg/kg dry soil)

Emergence

Mean ± SD

(% Reduction)

Day 21

Survival

Mean ± SD

(% Reduction)

Day 21

Dry Weight (g)

Mean ± SD

(% Reduction)

Day 21

Height (cm)

Mean ± SD

(% Reduction)

Day 21

Pooled Controls

4.8 ± 0.40

99 ± 5.0

0.304 ± 0.0766

15.0 ± 1.58

63

4.5 ± 1.07

(6%)

100 ± 0

(-1%)

0.312 ± 0.0431

(-2%)

15.2 ± 1.23

(-1%)

125

4.5 ± 0.76

(6%)

100 ± 0

(-1%)

0.296 ± 0.0761

(3%)

14.4 ± 2.01

(4%)

250

4.5 ± 0.53

(6%)

100 ± 0

(-1%)

0.269 ± 0.0789

(12%)

13.6 ± 2.61

(10%)

500

4.6 ± 0.52

(4%)

100 ± 0

(-1%)

0.262 ± 0.1006

(14%)

14.0 ± 3.59

(7%)

1000

4.5 ± 0.53

(6%)

97 ± 8.8

(2%)

0.258 ± 0.0941

(15%)

13.9 ± 3.35

(7%)

Mean ± SD = Mean plus or minus one standard deviation

*Treatment group mean was significantly different from the Pooled Control mean (p<0.05), lack of notation indicates lack of significance

 

Effects of 4-(1 Methyl-1-Phenylethyl)-N-[4-(1-Methyl-1-Phyenylethyl)Phenyl]Aniline onGlycine max(Soybean) Seedling Emergence, Survival, Dry Weight and Height in a 21-Day Seedling Emergence Test

Treatment Group

(mg/kg dry soil)

Emergence

Mean ± SD

(% Reduction)

Day 21

Survival

Mean ± SD

(% Reduction)

Day 21

Dry Weight (g)

Mean ± SD

(% Reduction)

Day 21

Height (cm)

Mean ± SD

(% Reduction)

Day 21

Pooled Controls

4.9 ± 0.25

99 ± 5.0

0.247 ± 0.0247

10.1 ± 1.25

63

4.6 ± 0.74

(6%)

98 ± 7.1

(1%)

0.275 ± 0.0291

(-12%)

9.9 ± 0.94

(1%)

125

4.4 ± 0.52*

(11%)

98 ± 7.1

(1%)

0.264 ± 0.0606

(-7%)

10.7 ± 1.12

(-7%)

250

4.6 ± 0.52

(6%)

97 ± 8.8

(2%)

0.241 ± 0.0246

(2%)

10.4 ± 0.86

(-3%)

500

4.8 ± 0.46

(4%)

94 ± 10.5

(4%)

0.279 ± 0.0508

(-13%)

10.9 ± 1.24

(-8%)

1000

4.8 ± 0.46

(4%)

98 ± 7.1

(1%)

0.269 ± 0.0371

(-9%)

10.5 ± 1.01

(-4%)

Mean ± SD = Mean plus or minus one standard deviation

*Treatment group mean was significantly different from the Pooled Control mean (p<0.05), lack of notation indicates lack of significance

 

Effects of 4-(1 Methyl-1-Phenylethyl)-N-[4-(1-Methyl-1-Phyenylethyl)Phenyl]Aniline onLactuca sativa(Lettuce) Seedling Emergence, Survival, Dry Weight and Height in a 21-Day Seedling Emergence Test

Treatment Group

(mg/kg dry soil)

Emergence

Mean ± SD

(% Reduction)

Day 21

Survival

Mean ± SD

(% Reduction)

Day 21

Dry Weight (g)

Mean ± SD

(% Reduction)

Day 21

Height (cm)

Mean ± SD

(% Reduction)

Day 21

Pooled Controls

4.6 ± 0.81

100 ± 0

0.036 ± 0.0165

5.0 ± 0.88

63

4.4 ± 0.74

(4%)

94 ± 10.5

(6%)

0.044 ± 0.0239

(-23%)

5.2 ± 1.63

(-4%)

125

4.5 ± 0.53

(1%)

95 ± 14.1

(5%)

0.039 ± 0.0177

(-8%)

4.6 ± 1.43

(8%)

250

3.9 ± 0.83

(15%)

100 ± 0

(0%)

0.021 ± 0.0087

(42%)

3.7 ± 1.37*

(25%)

500

4.4 ± 0.52

(4%)

97 ± 8.8

(3%)

0.032 ± 0.0150

(9%)

4.0 ± 0.87

(19%)

1000

3.4 ± 1.06*

(26%)

100 ± 0

(0%)

0.024 ± 0.0097

(33%)

3.5 ± 1.07*

(29%)

Mean ± SD = Mean plus or minus one standard deviation

*Treatment group mean was significantly different from the Pooled Control mean (p<0.05), lack of notation indicates lack of significance

 

Effects of 4-(1 Methyl-1-Phenylethyl)-N-[4-(1-Methyl-1-Phyenylethyl)Phenyl]Aniline onLycopersicon esculentum(Tomato) Seedling Emergence, Survival, Dry Weight and Height in a 21-Day Seedling Emergence Test

Treatment Group

(mg/kg dry soil)

Emergence

Mean ± SD

(% Reduction)

Day 21

Survival

Mean ± SD

(% Reduction)

Day 21

Dry Weight (g)

Mean ± SD

(% Reduction)

Day 21

Height (cm)

Mean ± SD

(% Reduction)

Day 21

Pooled Controls

4.6 ± 0.62

98 ± 6.3

0.053 ± 0.0193

5.3 ± 0.85

63

4.5 ± 0.76

(3%)

98 ± 7.1

(1%)

0.054 ± 0.0180

(-2%)

5.3 ± 0.74

(0%)

125

4.3 ± 1.04

(8%)

89 ± 11.5

(9%)

0.029 ± 0.0122*

(45%)

3.6 ± 0.96*

(33%)

250

4.0 ± 0.53

(14%)

97 ± 8.8

(2%)

0.033 ± 0.0152*

(38%)

3.9 ± 1.10*

(27%)

500

4.6 ± 0.74

(0%)

95 ± 9.3

(3%)

0.037 ± 0.0149

(31%)

4.3 ± 0.95

(19%)

1000

3.6 ± 1.19*

(22%)

91 ± 18.6

(8%)

0.032 ± 0.0196*

(40%)

4.0 ± 1.43*

(25%)

Mean ± SD = Mean plus or minus one standard deviation

*Treatment group mean was significantly different from the Pooled Control mean (p<0.05), lack of notation indicates lack of significance

 

 

Species

21-Day Emergence (mg/kg dry soil)

NOEC

LOEC

EC5

EC10

EC20

EC50

Monocots:

Avena sativa(oat)

Zea mays(corn)

Didcots:

Brassica napus(oil seed rape)

Glycine max(soy bean)

Lactuca sativa(lettuce)

Lycopersicon esulentum(tomato)

 

1000

1000

 

1000

1000

500

500

 

>1000

>1000

 

>1000

>1000

1000

1000

 

>1000

>1000

 

54

50

166

95

 

>1000

>1000

 

>1000

>1000

513

597

 

>1000

>1000

 

>1000

>1000

817

944

 

>1000

>1000

 

>1000

>1000

>1000

>1000

 

Species

21-Day Survival (mg/kg dry soil)

NOEC

LOEC

EC5

EC10

EC20

EC50

Monocots:

Avena sativa(oat)

Zea mays(corn)

Didcots:

Brassica napus(oil seed rape)

Glycine max(soy bean)

Lactuca sativa(lettuce)

Lycopersicon esulentum(tomato)

 

1000

1000

 

1000

1000

1000

1000

 

>1000

>1000

 

>1000

>1000

>1000

>1000

 

>1000

>1000

 

>1000

>1000

>1000

538

 

>1000

>1000

 

>1000

>1000

>1000

>1000

 

>1000

>1000

 

>1000

>1000

>1000

>1000

 

>1000

>1000

 

>1000

>1000

>1000

>1000

 

Species

21-Day Dry Weight (mg/kg dry soil)

NOEC

LOEC

EC5

EC10

EC20

EC50

Monocots:

Avena sativa(oat)

Zea mays(corn)

Didcots:

Brassica napus(oil seed rape)

Glycine max(soy bean)

Lactuca sativa(lettuce)

Lycopersicon esulentum(tomato)

 

1000

1000

 

1000

1000

1000

63

 

>1000

>1000

 

>1000

>1000

>1000

125

 

>1000

>1000

 

146

>1000

145

71

 

>1000

>1000

 

217

>1000

165

79

 

>1000

>1000

 

>1000

>1000

205

95

 

>1000

>1000

 

>1000

>1000

>1000

>1000

 

Species

21-Day Height (mg/kg dry soil)

NOEC

LOEC

EC5

EC10

EC20

EC50

Monocots:

Avena sativa(oat)

Zea mays(corn)

Didcots:

Brassica napus(oil seed rape)

Glycine max(soy bean)

Lactuca sativa(lettuce)

Lycopersicon esulentum(tomato)

 

1000

1000

 

1000

1000

125

63

 

>1000

>1000

 

>1000

>1000

250

125

 

>1000

>1000

 

142

>1000

98

75

 

>1000

>1000

 

>1000

>1000

136

87

 

>1000

>1000

 

>1000

>1000

225

111

 

>1000

>1000

 

>1000

>1000

>1000

>1000

 

Validity criteria fulfilled:
yes
Conclusions:
Test soil concentrations of up to 1000 mg/kg resulted in no adverse effects on the seedling emergence and early growth of four of the six species tested (A. sativa, Z. mays, B. napus, G. max).The NOEC and LOEC for Lactuca sativa (lettuce) were 125 and 250 mg/kg, respectively, based on seedling height. The NOEC and LOEC for Lycopersicon esculentum (tomato) were 63 and 125 mg/kg, respectively, based on seedling height and dry weight.
Executive summary:

STUDY: 4-(1-Methyl-1-Phenylethyl)-N-[4-(1-Methyl-1-Phenylethyl)Phenyl]Aniline: A Toxicity Test to Determine the Effects on Seedling Emergence and Growth of Terrestrial Plants

 

The study was conducted according to the OECD Guideline for the Testing of Chemicals, Guideline 208, Terrestrial Plant Test: Seedling Emergence and Seedling Growth Test.

 

TEST DESIGN: Two monocot and four dicot species of terrestrial non-target plants were exposed to a series of five geometrically spaced test concentrations of the test substance incorporated in soil, as well as a negative control (containing water purified by reverse osmosis) and a solvent control (acetonitrile). Each test and control group consisted of eight replicate test pots containing five planted seeds of one species. After planting, test pots were placed on a greenhouse bench top according to a randomized block design.

The test duration was 21 days following planting (22 days for tomato), which was at least 14 days after 50% emergence of control plants for all species. The number of emerged seedlings was observed weekly and the percentage of surviving seedlings, plant condition, seeding height and dry weight were determined at test termination.

 

NOMINAL TEST LEVELS: 0 (Negative Control), Solvent Control (acetonitrile), 63, 125, 250, 500 and 1000 mg /kg (milligrams of test substance per kilogram of dry soil).

 

Test soil concentrations of up to 1000 mg/kg resulted in no adverse effects on the seedling emergence and early growth of four of the six species tested (A. sativa, Z. mays, B. napus, G. max).

The NOEC and LOEC for Lactuca sativa (lettuce) were 125 and 250 mg/kg, respectively, based on seedling height. The NOEC and LOEC for Lycopersicon esculentum (tomato) were 63 and 125 mg/kg, respectively, based on seedling height and dry weight.

Description of key information

The study was conducted with read-across substance, 4-(1-Methyl-1-Phenylethyl)-N-[4-(1-Methyl-1-Phenylethyl)Phenyl]Aniline according to the OECD Guideline for the Testing of Chemicals, Guideline 208, Terrestrial Plant Test: Seedling Emergence and Seedling Growth Test. Two monocot and four dicot species of terrestrial non-target plants were exposed to a series of five geometrically spaced test concentrations of the test substance incorporated in soil, as well as a negative control (containing water purified by reverse osmosis) and a solvent control (acetonitrile). The test duration was 21 days following planting (22 days for tomato), which was at least 14 days after 50% emergence of control plants for all species. The number of emerged seedlings was observed weekly and the percentage of surviving seedlings, plant condition, seeding height and dry weight were determined at test termination. The test concentrations were as follows: 0 (Negative Control), Solvent Control (acetonitrile), 63, 125, 250, 500 and 1000 mg /kg (milligrams of test substance per kilogram of dry soil).

 

Test soil concentrations of up to 1000 mg/kg resulted in no adverse effects on the seedling emergence and early growth of four of the six species tested (A. sativa, Z. mays, B. napus, G. max). The NOEC and LOEC for Lactuca sativa (lettuce) were 125 and 250 mg/kg, respectively, based on seedling height. The NOEC and LOEC for Lycopersicon esculentum (tomato) were 63 and 125 mg/kg, respectively, based on seedling height and dry weight.

Key value for chemical safety assessment

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

Additional information