chloroethane

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:

supporting study

Study period:

12 OCT - 16 DEC 1993

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: GLP - guideline study with acceptable restrictions

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 208 (Terrestrial Plants Test: Seedling Emergence and Seedling Growth Test)

Deviations:

yes

Principles of method if other than guideline:

The test method was modelled after OECD guideline 208 but adapted to the gaseous nature of the test substance. Thus, the substance was not mixed with soil but the plants were exposed to the gas in closed chambers. In contrast to the guideline only the effect was only tested with two plant species. Two assays were conducted. In a first assay both plant species were exposed. In the second assay only Lepidum sativum was exposed to the substance.

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

- Concentrations: 10 ppmv and 100 ppmv nominal
- Sampling method: samples for gas chromatographic analysis of ethylchlorid within the gas phase were taken from the influent and effluent

Vehicle:

no

Species:

Avena sativa

Plant group:

Monocotyledonae (monocots)

Details on test organisms:

- Common name: oat
- Plant family: Poaceae
- Source of seed: Hüls Gartenbaubetrieb

Species:

Lepidum sativum

Plant group:

Dicotyledonae (dicots)

Details on test organisms:

- Common name: garden cress
- Plant family: Brassicaceae
- Source of seed: Hüls Gartenbaubetrieb

Test type:

vegetative vigour test

Study type:

laboratory study

Substrate type:

natural soil

Limit test:

no

Total exposure duration:

17 d

Test temperature:

Assay 1: 20 - 26 °C
Assay 2: 23 - 29 °C

pH:

6.0

Moisture:

approximately 60% of maximum water holding capacity

Details on test conditions:

TEST SYSTEM
- Testing facility: Hüls AG, Marl, Germany
- Test container (type, material, size): plastic pots covered with filter paper exposed to the substance in a closed chamber (volume: 74 L)
- Amount of soil: 100 g
- Method of seeding: seeds were given to the substrate (no further information concerning method of seeding)
- No. of seeds per container: 5
- No. of plants (retained after thinning): no thinning
- No. of replicates per treatment group: 4
- No. of replicates per control: 4


SOURCE AND PROPERTIES OF SUBSTRATE (if soil)
- Soil taxonomic classification: LUFA soil according to OECD 208
- Organic carbon (%): 1.34 ± 0.14%
- Maximum water holding capacity (in % dry weigth): no data


GROWTH CONDITIONS
- Photoperiod: 16 light / 8 darkness
- Light source: mercury vapour lamp
- Light intensity and quality: 2000 - 4000 lux

Nominal and measured concentrations:

nominal: 0, 10 and 100 ppmv (mL/m³)
measured: the measured values for 100 ppmv were reduced by 4 - 21 % compared to the concentrations measured in the supply air. The concentrations at 10 ppmv remained constant in supply and exhaust air.

Reference substance (positive control):

no

Species:

Lepidum sativum

Duration:

14 d

Dose descriptor:

EC50

Effect conc.:

> 100 other: ppmv

Basis for effect:

growth

Species:

Lepidum sativum

Duration:

14 d

Dose descriptor:

other: EC20

Effect conc.:

100 other: ppmv

Basis for effect:

growth

Species:

Avena sativa

Duration:

14 d

Dose descriptor:

NOEC

Effect conc.:

100 other: ppmv

Basis for effect:

growth

Remarks:

and emergence

Details on results:

Avena sativa:
no effects on plant growth were be observed. No morphological anomalies observed.

Lepidium sativum:
Assay1:
Plant growth was 20% reduced after exposure to 10 and 100 ppmv ethylchlorid . No morphological anomalies observed.
Assay 2:
Plant growth was 20% reduced at a concentration of 100 ppmv ethylchlorid. No morphological anomalies observed.

Nominal concentration [mL/m^3]	Fresh weight [mg] at test end
	Avena sativa	Lepidum sativum 1^sttest	Lepidum sativum 2^ndtest
0	232	63	43
10	214	46	38
100	237	49	34

Additional information

Chloroethane is a gaseous substance and thus will mainly distribute to the air if released to the environment. There is no intended release of the substance to soil during its lifecycle. An exposure of the terrestrial compartment is therefore not anticipated.

Due to its gaseous nature chloroethane is characterised by a high vapour pressureof 134200 Pa at 20 °C (62330 Pa at 0 °C) and subsequently by a high evaporation rate from water to air as indicated by aHenry's Law constant of 1124.70 Pa m³/mol calculated for the substance. If the substance is released to the waste water it will rapidly evaporate from the water phase in conventional sewage treatment plants during the primary treatment. The substance will not adsorp to suspended matter or activated sludge as indicated by the low log Pow (1.34) and the correlated log Koc value (<3) . An exposure of soil via sewage sludge application can be excluded.

One study investigating the effect of chloroethane to terrestrial plants is available. The test investigated the effect of the substance on emergence and growth of the plant species Avena sativa and Lepidum sativum. The plants were exposed to the gas at concentrations of 10 and 100 ppmv in a closed chamber. The test was terminated after 14 days. Avena sativa was not affected by the substance. Whereas the growth of Lepidum sativum was reduced by 20% compared to control. Thus, the EC50(14d) for both plant species is > 100 ppmv.