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Ecotoxicological information

Toxicity to terrestrial plants

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Reference
Endpoint:
toxicity to terrestrial plants: long-term
Type of information:
read-across based on grouping of substances (category approach)
Adequacy of study:
key study
Study period:
From November 19, 2003 to March 03, 2004
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Remarks:
RA study
Justification for type of information:
Refer to the section 13 for details on the read across justification. The toxicity to terrestrial plants study with the read across substance is considered sufficient to fulfil the information requirements as further explained in the provided endpoint summary.
Reference:
Composition 1
Qualifier:
according to
Guideline:
OECD Guideline 208 (Terrestrial Plants Test: Seedling Emergence and Seedling Growth Test)
Deviations:
no
GLP compliance:
yes (incl. certificate)
Test material information:
Composition 1
Specific details on test material used for the study:
- Purity: 49.9% of test substance in water
Analytical monitoring:
yes
Remarks:
HPLC/UV
Details on sampling:
The test substance is soluble
Details on preparation and application of test substrate:
- Natural soil:
The natural soil was collected on October 10, 2003.
Sampling site 1: Mr Castagnède, Parcelle Guilhem (40110 Arengosse, France). Plant cover = peas, under agro biological practice.
Sampling site 2: Mr Dupouy, Parcelle Parille (40500 Coudures, France). Plant cover = triticales, under agro biological practice.
Both the soil samples were sieved through a 2 mm aperture size. They were mixed 50/50 w/w dry weight, and the resulting soil was sampled for further analysis. The stock soil was stored outdoors in plastic containers, which allowed free access of air.
Characteristics of the soil were as follows:
Method Results
Sieve analysis NF X31-107 Sand 48.2 %
Lime 42.8 %
Clay 9.0 %
Total water ISO 14238 holding capacity appendix A 38.3 % dry soil
pH (in water) ISO 10390 : 6.70

Catiionic exchange cap. NF X31-130 7.4 meq./100 g
Total OC NF X31-109 1.41 % dry weight
Nitrogen ISO 11261 0.084 % dw

- Sand:
Fontainebleau sand, min. 99.8% SiO2
Particle size: 150-210 µm
Species:
other: Sinapis alba; Trifolium pratense; Triticum aestivum
Plant group:
other: Dicotyledonae; Monocotyledonae
Details on test organisms:
- Cruciferae (Brassicaceae); Sinapis alba; Mustard; source: agro-biologically produced seeds ‘white mustard’, Le Biau Germe, batch 2001, expiry date : 12/2004 (47360 Montpezat d’Agenais, France)
- Leguminosae (Fabaceae); Trifolium pratense; red clover; source: agro-biologically produced seeds ‘Trèfle violet’. Le Biau Germe, batch CB1, expiry date : 12/2006 (47360 Montpezat d’Agenais, France)
- Gramineae (Poceae); Triticum aestivum; wheat; source: agro-biologically produced seeds ‘Blé tendre à germer’, Celnat, batch n° 3 273120 010304,
expiry date 13/09/2004 (43700 Saint-Germain-Laprade, France)
Test type:
seedling emergence toxicity test
Study type:
laboratory study
Substrate type:
other: natural soil and quartz
Limit test:
no
Total exposure duration:
16 d
Remarks:
16d after 50% of the control plants had emerged
Test temperature:
Natural soil: Extreme values 16.0-23°C, the average daily value ranged between 17.0 and 22.0°C.
Sand: Extreme values 14.0-22.5°C, the average daily value ranged between 15.5 and 20.0°C.
Details on test conditions:
- Species: 
Monocotyledonae:  - Tritium aestivum (wheat (Category 1))
Dicotyledonae:  - Sinapis alba (mustard);  - Trifolium pratense (red clover (Category 3))
- Tested with 40 plants per replicate per dose, using 4 replicates. 
- Test was performed on natural soil and sand.
- Concentrations:   
Natural soil (mg/kg): 0, 476.6, 856.2, 1540.9, 2772.2 and 4990.0  
Sand (mg/kg): 0, 28.8, 55.8, 93.4, 166.8 and 300.5
- Endpoint/Type of test: Emergence, growth
- Design: natural soil, sand
- Duration: 16d after 50% of the control plants had emerged.
Nominal and measured concentrations:
- Natural soil (mg/kg): 0, 476.6, 856.2, 1540.9, 2772.2 and 4990.0  
- Sand (mg/kg): 0, 28.8, 55.8, 93.4, 166.8 and 300.5
Reference substance (positive control):
no
Key result
Species:
Trifolium pratense
Duration:
16 d
Dose descriptor:
EC50
Effect conc.:
634 mg/kg soil dw
Conc. based on:
act. ingr.
Basis for effect:
other: Emergence, growth in natural soil
Remarks on result:
other: Wheat; 5% confidence limits: 290-1390
Key result
Species:
Sinapis alba
Duration:
16 d
Dose descriptor:
EC50
Effect conc.:
537 mg/kg soil dw
Conc. based on:
act. ingr.
Basis for effect:
other: Emergence, growth in natural soil
Remarks on result:
other: Mustard; 95% confidence limits: 187-1539
Key result
Species:
Triticum aestivum
Duration:
16 d
Dose descriptor:
EC50
Effect conc.:
1 960 mg/kg soil dw
Conc. based on:
act. ingr.
Basis for effect:
other: Emergence, growth in natural soil
Remarks on result:
other: Red clover; 95% confidence limits: 758 - 5066
Key result
Species:
Trifolium pratense
Duration:
16 d
Dose descriptor:
EC50
Effect conc.:
141 mg/kg soil dw
Conc. based on:
act. ingr.
Basis for effect:
other: Emergence, growth in quartz sand
Key result
Species:
Sinapis alba
Duration:
16 d
Dose descriptor:
EC50
Effect conc.:
73 mg/kg soil dw
Conc. based on:
act. ingr.
Basis for effect:
other: Emergence, growth in quartz sand
Key result
Species:
Triticum aestivum
Duration:
16 d
Dose descriptor:
EC50
Effect conc.:
74 mg/kg soil dw
Conc. based on:
act. ingr.
Basis for effect:
other: Emergence, growth in quartz sand
Key result
Species:
Trifolium pratense
Duration:
16 d
Dose descriptor:
EC50
Effect conc.:
684 mg/kg soil ww
Conc. based on:
act. ingr.
Basis for effect:
other: Emergence, growth in natural soil
Key result
Species:
Sinapis alba
Duration:
16 d
Dose descriptor:
EC50
Effect conc.:
342 mg/kg soil ww
Conc. based on:
act. ingr.
Basis for effect:
other: Emergence, growth in natural soil
Key result
Species:
Triticum aestivum
Duration:
16 d
Dose descriptor:
EC50
Effect conc.:
309 mg/kg soil ww
Conc. based on:
act. ingr.
Basis for effect:
other: Emergence, growth in natural soil
Key result
Species:
Trifolium pratense
Duration:
16 d
Dose descriptor:
EC50
Effect conc.:
105 mg/kg soil ww
Conc. based on:
act. ingr.
Basis for effect:
other: Emergence, growth in quartz sand
Key result
Species:
Sinapis alba
Duration:
16 d
Dose descriptor:
EC50
Effect conc.:
31 mg/kg soil ww
Conc. based on:
act. ingr.
Basis for effect:
other: Emergence, growth in quartz sand
Key result
Species:
Triticum aestivum
Duration:
16 d
Dose descriptor:
EC50
Effect conc.:
19 mg/kg soil ww
Conc. based on:
act. ingr.
Basis for effect:
other: Emergence, growth in quartz sand
Details on results:
See 'Any other information on results incl. tables'
Results with reference substance (positive control):
-

Table 1. Results (based on active test substance)

Results

wheat

mustard

red clover

Test on natural soil

LC50 (based on emergence)

> 4990.0 mg/kg

3881 mg/kg

[2772.2 – 4990.0]

> 4990.0 mg/kg

EC50 (based on wet weight)

684 mg/kg

[359 – 1302]

342 mg/kg

[53 – 2185]

309 mg/kg

[151 – 632]

EC50 (based on dry weight)

1960 mg/kg

[758 – 5066]

537 mg/kg

[187 – 1539]

634 mg/kg

[290 – 1390]

Test on quartz sand

LC50 (based on emergence)

234 mg/kg

[167 – 301]

130 mg/kg

[93 – 167] mg/kg

197 mg/kg

[93 – 301] mg/kg

EC50 (based on wet weight)

105 mg/kg

[7 – 204]

31 mg/kg

[0 – 160]

19 mg/kg

[0 – 329]

EC50 (based on dry weight)

141 mg/kg

[78 – 205]

73 mg/kg

[0 – 99]

74 mg/kg

[0 – 474]

The most sensitive was plant T. pratense with EC50 = 634 mg/kg soil dry weight.

Conclusion: The effects of test substance exhibited great deviation between sand and natural soil. In sand toxic effects take place at lower concentrations than in soil, this is probably due to the lower bioavailability of test substance in soil caused by stronger adsorption.

The test was considered as valid on the basis of percent emergence and further growth of the plant in the water control.

The side-effects exhibited great deviation between quartz sand and natural soil. The extraction of the active substance proved that the natural soil had a strong sorbing effect, and the total recovery was not achieved even when acidified methanol was used. That was not the case with quartz sand, and this was taken as the source of the differences: the availability of the active substance for the plants differed, depending on the nature of the soil substrate.

Validity criteria fulfilled:
yes
Remarks:
The test was considered as valid on the basis of percent emergence and further growth of the plant in the water control.
Conclusions:
Based on the results of the read across study, the side-effects exhibited great deviation between quartz sand and natural soil. In sand, toxic effects take place at lower concentrations than in soil. This was probably due to the lower bioavailability of test substance in soil caused by a stronger adsorption. Further, as the toxicity to terrestrial plants in sand is not representative of the natural environment, the EC50 in natural soil can be considered as a reasonable worst case for terrestrial plant species. The 16d EC50 values in soil, based on the effect on emergence and growth were 537, 634 and 1960 mg a.i./kg dw of soil for S. alba, T. pratense and T. aestivum, respectively; while those in sand were 73, 74 and 141 mg a.i./kg dw of sand respectively .
Executive summary:

A study was conducted to determine the toxicity ot terrestrial plants of the read across substance, quaternary ammonium compounds, benzyl C12-C16 (even numbered)-alkyldimethyl chlorides (C12-16 ADBAC), according to OECD Guideline 208, in compliance with GLP. A seedling emergence and seedling growth test was realised. Sinapis alba, Trifolium pratense and Triticum aestivum were used. The substance was tested with 40 plants per replicate per dose using 4 replicates for 16 days. The study was performed using natural soil and sand at the concentrations of 0, 476.6, 856.2, 1540.9, 2772.2 and 4990.0 mg/kg and 0, 28.8, 55.8, 93.4, 166.8 and 300.5 mg/kg, respectively. Analytical determination was performed for the test substance. The test was considered as valid on the basis of percent emergence and further growth of the plant in the water control. The extraction of the active substance proved that the natural soil had a strong sorbing effect and the total recovery was not achieved even when acidified methanol was used as an extraction solvent. That was not the case with quartz sand. Based on the results of the read across study, the side-effects exhibited great deviation between quartz sand and natural soil. In sand, toxic effects take place at lower concentrations than in soil. This was probably due to the lower bioavailability of test substance in soil caused by a stronger adsorption. Further, as the toxicity to terrestrial plants in sand is not representative of the natural environment, the EC50 in natural soil can be considered as a reasonable worst case for terrestrial plant species. The 16d EC50 values in soil, based on the effect on emergence and growth were 537, 634 and 1960 mg a.i./kg dw of soil for S. alba, T. pratense and T. aestivum, respectively; while those in sand were 73, 74 and 141 mg a.i./kg dw of sand, respectively (Servajean, 2004).

Description of key information

Key value for chemical safety assessment

Short-term EC50 or LC50 for terrestrial plants:
537 mg/kg soil dw

Additional information

A study was conducted to determine the toxicity ot terrestrial plants of the read across substance, , quaternary ammonium compounds, benzyl C12-C16 (even numbered)-alkyldimethyl chlorides (C12-16 ADBAC), according to OECD Guideline 208, in compliance with GLP. A seedling emergence and seedling growth test was realised. Sinapis alba, Trifolium pratense and Triticum aestivum were used. The substance was tested with 40 plants per replicate per dose using 4 replicates for 16 days. The study was performed using natural soil and sand at the concentrations of0, 476.6, 856.2, 1540.9, 2772.2 and 4990.0 mg/kg and0, 28.8, 55.8, 93.4, 166.8 and 300.5 mg/kg, respectively.Analytical determination was performed for the test substance. The test was considered as valid on the basis of percent emergence and further growth of the plant in the water control.The extraction of the active substance proved that the natural soil had a strong sorbing effect and the total recovery was not achieved even when acidified methanol was used as an extraction solvent. That was not the case with quartz sand. Based on the results of the read across study, the side-effects exhibited great deviation between quartz sand and natural soil. In sand, toxic effects take place at lower concentrations than in soil. This was probably due to the lower bioavailability of test substance in soil caused by a stronger adsorption.Further, as the toxicity to terrestrial plants in sand is not representative of the natural environment, the EC50 in natural soil can be considered as a reasonable worst case for terrestrial plant species.The 16d EC50 values in soil, based on the effect on emergence and growth were 537, 634 and 1960 mg a.i./kg dw of soil for S. alba, T. pratense and T. aestivum, respectively; while those in sand were 73, 74 and 141 mg a.i./kg dw of sand, respectively (Servajean, 2004).