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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:
1998-07-30 to 1998-08-17
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Remarks:
Guideline study. The study was conducted according to an OECD test guideline, and in compliance with GLP. However exposure was to the test substance in gaseous phase.
Qualifier:
according to guideline
Guideline:
OECD Guideline 208 (Terrestrial Plants Test: Seedling Emergence and Seedling Growth Test)
Deviations:
no
GLP compliance:
yes (incl. QA statement)
Analytical monitoring:
yes
Details on sampling:
The gasous phase was sampled and analysed on days 1, 4, 8 and 11.
Vehicle:
no
Details on preparation and application of test substrate:
- Method of mixing into soil: Not applicable. The test substance exposure was via a gaseous phase.

Species:
Avena sativa
Plant group:
Monocotyledonae (monocots)
Details on test organisms:
- Common name: Oat
Species:
Lepidum sativum
Plant group:
Dicotyledonae (dicots)
Details on test organisms:
- Common name: Cress
Test type:
seedling emergence toxicity / vegetative vigour test
Study type:
laboratory study
Substrate type:
other: sieved soil
Limit test:
no
Total exposure duration:
17 d
Test temperature:
21 - 26 ºC
pH:
6.4 (Control)
Moisture:
45-70% of water capacity
Details on test conditions:
TEST SYSTEM

- The pots containing the seedlings were held in a gaseous exposure chambers. The gas in the exposure chambers was changed at the rate of 10 litres/h.

- Amount of soil: 100 g

- Method of seeding:

- No. of seeds per container: 5

- No. of replicates per treatment group: 4

- No. of replicates per control: 4

SOURCE AND PROPERTIES OF SUBSTRATE

- Source: FA.LUFA Speyer, Sp.2.3

- Soil texture

- <20 μm: 10 - 20%:

- Organic carbon (%): 1.34%

GROWTH CONDITIONS

- Photoperiod: 16 h light/8h dark

- Light intensity: 300-500 Lux continuous in germination phase. 2000 - 3000 Lux day/70 - 120 Lux night in growth phase

- Day/night temperatures: 22 - 26 ºC

EFFECT PARAMETERS MEASURED: Seedling wet weight on Day 17.

VEHICLE CONTROL PERFORMED: no

TEST CONCENTRATIONS

- 10 and 124 ppm volume gaseous
Nominal and measured concentrations:
Nominal concentration: 0 (Control), 10 and 124 ppm volume (gaseous)

Mean measured concentrations (10.6 and 122 ppm volume) were within +/-20% of nominal. The results are therefore expressed with reference to nominal concentrations.
Reference substance (positive control):
no
Species:
Avena sativa
Duration:
17 d
Dose descriptor:
NOEC
Effect conc.:
10 other: ppm volume
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth
Species:
Avena sativa
Duration:
17 d
Dose descriptor:
other: EC40
Effect conc.:
124 other: ppm volume
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth
Key result
Species:
Lepidum sativum
Duration:
17 d
Dose descriptor:
NOEC
Effect conc.:
10 other: ppm volume
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth
Key result
Species:
Lepidum sativum
Duration:
17 d
Dose descriptor:
other: EC53
Effect conc.:
124 other: ppm volume
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth
Reported statistics and error estimates:
ECx values for growth effects were determined directly from the test results. NOECs were determined by t-test

Table 1. Results of analysis of exposure concentrations

 Day  Measured concentration in Control (ppm Vol)     Measured concentration in nominal 10 ppm Vol    Measured concentration in nominal 124 ppm Vol  
 1  -  10.0 119
 4  -  9.8 119
 8 -  9.8 124
 11  <1 12.8 125

 Mean measured concentration

 - 10.6 122

Table 2. Test results - growth after 17 days

 Test concentration (ppm Vol)   Mean plant wet weight (mg) - Oat  Mean plant wet weight (mg) - Cress
 Control 426 (+/-73)  124 (+/-17)
 10  425 (+/-124)  143 (+/-21)
 124 255 (+/-43)*  58 (+/-11)*

*Significantly different from the Control

Validity criteria fulfilled:
yes
Conclusions:
A NOEC of 10 ppm (by volume) has been determined for the effects of the test substance on growth of Avena sativa and Lepidium sativum . 17-day EC40 and EC53 values of 124 ppm have also been determined for effects on growth of the two species. The test organisms were exposed to the substance in gaseous phase.

Description of key information

17-Day EC40 and EC53 values of 124 ppm and a NOEC value of 10 ppm for the effects of the test substance on growth of Avena sativa and Lepidium sativum. The test organisms were exposed to the substance in gaseous phase.

Key value for chemical safety assessment

Additional information

A NOEC of 10 ppm (by volume) has been determined for the effects of tetramethylsilane (CAS 75-76-3; EC No. 200-899-1) on growth of Avena sativa and Lepidium sativum. 17-day EC40 and EC53 values of 124 ppm have also been determined for effects on growth of the two species (Hüls, 1998). The test organisms were exposed to the substance in gaseous phase using gaseous exposure chambers. The study was conducted in accordance with OECD TG 208, modified for gaseous exposure, and in compliance with GLP.