Dibenzylbenzene, ar-methyl derivative

Toxicity to terrestrial plants

Link to relevant study record(s)

Reference

Endpoint:

toxicity to terrestrial plants: short-term

Type of information:

experimental study

Adequacy of study:

key study

Study period:

from 1990-04-25 to 1990-06-05

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Qualifier:

according to guideline

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:

The purity of the material used for the test was lower than the purity of the actual material. It contained ca. 26% of isomers of dimethyl tribenzenes. However, based on comparable basic structure of the impurities and the assumption that any toxic effects would increase with higher molecular weight and lipophilicity, we regard that the studies conducted with the lower purity material being "worst case" and can be used for the evaluation of the actual product.

Analytical monitoring:

no

Vehicle:

no

Details on preparation and application of test substrate:

- Method of mixing into soil: 1, 10 and 100 mg of test substance were mixed with 1000 g soil
- Controls: soil without test substance

Species:

Triticum aestivum

Plant group:

Monocotyledonae (monocots)

Details on test organisms:

- Common name: wheat
- Plant family: Poaceae
- Variety: not mentioned
- Source of seed: not mentioned
- Prior seed treatment/sterilization: not mentioned
- Historical germination of seed (germination of seed lot tested): not tested
- Seed storage: not mentioned

Species:

Raphanus sativus

Plant group:

Dicotyledonae (dicots)

Details on test organisms:

- Common name: fenugreek
- Plant family: Brassicaceae
- Variety: not mentioned
- Source of seed: not mentioned
- Prior seed treatment/sterilization: not mentioned
- Historical germination of seed (germination of seed lot tested): ot tested
- Seed storage: not mentioned

Species:

Trifolium ornithopodioides

Plant group:

Dicotyledonae (dicots)

Details on test organisms:

- Common name: garden cress
- Plant family: Faboideae
- Variety: not mentioned
- Source of seed: not mentioned
- Prior seed treatment/sterilization: not mentioned
- Historical germination of seed (germination of seed lot tested): ot tested
- Seed storage: not mentioned

Test type:

seedling emergence toxicity test

Study type:

laboratory study

Substrate type:

artificial soil

Limit test:

no

Total exposure duration:

20 d

Post exposure observation period:

none

Test temperature:

22 - 24 °C

pH:

7.3 - 7.5

Moisture:

approx. 25 % , no further details mentioned

Details on test conditions:

TEST SYSTEM
- Testing facility: partly air-conditioned room, no further details mentioned
- Test container (type, material, size): flowerpots of black plastics (diameter top/bottom approx. 8/6 cm; height approx. 9-10 cm)
- Amount of soil: 100 g test substrate per planting pot
- Method of seeding: not mentioned
- No. of seeds per container: 5
- No. of plants (retained after thinning): no thinning performed
- No. of replicates per treatment group: 20 (for each plant species 4 replicates with 5 seeds each)
- No. of replicates per control: 20 (4 replicates with 5 seeds each)

SOURCE AND PROPERTIES OF SUBSTRATE (if soil)
- Composition (if artificial substrate): corresponded to the requirements of the guideline, no further details mentioned
- Organic carbon (%): 0.18 %
- Maximum water holding capacity (in % dry weigth): approx. 25 %
- CEC: not mentioned
- Pretreatment of soil: sieved with 0.5 cm mesh, no further details mentioned
- Storage (condition, duration): not mentioned

NUTRIENT MEDIUM: not used

GROWTH CONDITIONS
- Photoperiod: 16 h light, 8 h darkness
- Light source: not mentioned
- Light intensity and quality: seeding phase: 10 h at 200 Lux, 14 h darkness; growth phase: 10 h at 11 000 Lux, 14 h darkness
- Day/night temperatures: 21 - 25 °C, not differentiated between day and night
- Relative humidity (%): not mentioned
- Wind velocity: not applicable
- Air exchange rate: not mentioned
- Watering regime and schedules:
- Water source/type: not mentioned
- Volume applied: not mentioned
- Interval of applications: once during the test
- Method of application: not mentioned
- Any pest control method/fertilization (if used): not used

ACCLIMATION PERIOD: not mentioned

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : emergence of seeds, weight of overground part of plant at the end of the test

- Phytotoxicity rating system (if used): not used

Nominal and measured concentrations:

1, 10 and 100 mg/kg soil (nominal), dry weight

Reference substance (positive control):

no

Key result

Species:

Triticum aestivum

Duration:

19 d

Dose descriptor:

LC50

Effect conc.:

> 100 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

seedling emergence

Key result

Species:

Triticum aestivum

Duration:

19 d

Dose descriptor:

EC50

Effect conc.:

> 100 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

growth

Key result

Species:

Raphanus sativus

Duration:

20 d

Dose descriptor:

LC50

Effect conc.:

> 100 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

seedling emergence

Key result

Species:

Raphanus sativus

Duration:

20 d

Dose descriptor:

EC50

Effect conc.:

> 100 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

growth

Key result

Species:

Trifolium ornithopodioides

Duration:

20 d

Dose descriptor:

LC50

Effect conc.:

> 100 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

seedling emergence

Key result

Species:

Trifolium ornithopodioides

Duration:

20 d

Dose descriptor:

EC50

Effect conc.:

> 100 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

growth

Key result

Species:

Triticum aestivum

Duration:

19 d

Dose descriptor:

NOEC

Effect conc.:

100 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

other: Seedling emergence and growth

Key result

Species:

Raphanus sativus

Duration:

20 d

Dose descriptor:

NOEC

Effect conc.:

100 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

other: seedling emergence and growth

Key result

Species:

Trifolium ornithopodioides

Duration:

20 d

Dose descriptor:

NOEC

Effect conc.:

100 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

other: seedling emergence and growth

Details on results:

SEEDLING EMERGENCE
- Percent seedling emergence: see below (remarks on results)
- Percent survival: see below (remarks on results)
- Plant height: not measured
- Dry weight: not measured, fresh weight was measured: see below
- Abnormal seed development or appearance: not determined
- Other effects: none mentioned

Results with reference substance (positive control):

no reference substance tested

Reported statistics and error estimates:

not mentioned

- Effect data: Wheat

- Nominal concentrations: 1, 10, 100 mg/kg dry soil

- Effect data:

- Emergence: 100 % / 95 % / 95 %

- Plant growth: 147.4 ± 39.1 mg / 132.6 ± 31.3 mg / 109.2 ± 39.5 mg

RESULTS CONTROL:

- Emergence: 100 %

- Plant growth: 121.2 ± 37.6 mg

- Effect data: Radish

- Nominal concentrations: 1, 10, 100 mg/kg dry soil

- Effect data:

- Emergence: 100 % / 100 % / 96 %

- Plant growth: 219.4 ± 52.7 mg / 282.8 ± 88.8 mg / 283.2 ± 117.2 mg

RESULTS CONTROL:

- Emergence: 96 %

- Plant growth: 152.6 ± 50.7 mg

- Effect data: Fenucreek

- Nominal concentrations: 1 / 10 / 100 mg/kg dry soil

- Effect data:

- Emergence: 96 % / 76 % / 92 %

- Plant growth: 112.9 ± 32.9 mg / 114.6 ± 29.1 mg / 110.4 ± 29.6 mg

RESULTS CONTROL:

- Emergence: 88 %

- Plant growth: 107.9 ± 29.6 mg

Validity criteria fulfilled:

yes

Conclusions:

Not phytotoxic under test conditons at concentrations up to a concentration of 100 mg/kg dry soil.

Executive summary:

The test item Marlotherm S was tested on effects of seedling emergence and seedling growth on three non-target plant species representing three plant families according to OECD Guideline for Testing of Chemicals No. 208 (from 4 April 1984).

For the test the following plant species were selected: wheat (Triticum aestivum) for Category 1, radish (raphanus sativus) for Category 2 and fenucreek (trifolium ornithopadioides) for Category 3. A control and three concentrations (1, 10 and 100 mg/kg dry soil (nominal)) were tested for each species. The number of seedlings that emerged were recorded. After 19 days in the test with wheat resp. 20 days in the test with radish and fenucreek the plants were harvested and weighed.

All tested species showed no phytotoxic effects at the tested concentrations of Marlotherm S compared to the control. The LC50 for seedling emergence and the EC50 for growth of Triticum aestivum, raphanus sativus and trifolium ornithopdioides were therefore observed to be greater than 100 mg/kg dry soil.

Description of key information

Not phytotoxic under test conditions at concentrations up to a concentration of 100 mg/kg dry soil. Therefore, no EC50, EC10 are derived.