Oct-2-ene

Toxicity to terrestrial plants

Link to relevant study record(s)

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

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Non-GLP, non guideline, avalable as unpublished report, acceptable with restrictions

Justification for type of information:

Read-across between the target substance Oct-2-ene (EC 203-894-2 / CAS 111-67-1) and source substance 1-Tetradecene (EC 214-306-9/ CAS 1120-36-1) is based upon the similarity of the chemical structures and their respective physico-chemical properties. The ECHA Read-Across Assessment Framework (RAAF) states that substances with qualitatively similar properties can form the basis of read-across in circumstances where the source and target substances share such similar characteristics.
Target substance Oct-2-ene and source substance 1-Tetradecene are each mono-constituent linear olefins. Structurally, the differences between source and target substances include: 1) the length of the carbon chain (eight for the target substance, and fourteen for the source substance); and 2) the location of the carbon-carbon double bond (uniformly at the C2 position for the target substance, but uniformly at the C1 terminal position for the source substance).
The target and source substances both fit within the boundaries of chemical category of higher olefins. Studies conducted by the HOPA consortium on a large range of higher olefin category members (including 1-Tetradecene) demonstrated sufficiently similar physico-chemical, environmental fate and toxicological properties to substantiate the basis for read-across; although category members of a carbon chain length C10 or greater may exhibit a reduced acute aquatic toxicity attributable to reduced water solubility, the environmental toxicity of all category member is expected to be manifested as non-polar narcosis. In addition, both 1-Tetradecene and Oct-2-ene are expected to exhibit sufficient adsorption to soil and sediment to exhibit similar long-term toxicity; therefore, read-across with respect to sediment and terrestrial toxicity endpoints is appropriate. Justification for inclusion of Oct-2-ene within the boundaries of the higher olefins category, and the relevance of each category member as an analogue substance to Oct-2-ene, is provided in Section 13 (Document name: “HOPA Higher Olefins CJD with Category Matrix Report [rev 1 Sept 2016]”; Document name: "ACC Product Stewardship Summary for Higher Olefins Category (2008-12-03)”).

Reason / purpose for cross-reference:

read-across source

Principles of method if other than guideline:

The acute toxicity of the test substance to barley was tested in a laboratory bioassay. Natural soil exposed in the field to the test substance was sampled over time. The bulk sample was analysed for physico chemical parameters and the concentration of the test substance. Barley was exposed to the soil samples and the effects on shoot and root length and weight recorded. Effects on barley grown in the field are also reported.

GLP compliance:

not specified

Specific details on test material used for the study:

Details on properties of test surrogate or analogue material (migrated information):
No data reported

Analytical monitoring:

yes

Details on sampling:

A natural silty loam soil was dosed with drill cuttings containing the test substance in September 2001. Soil samples were taken after 2.5, 7, 8 and 10.5 months. 15 soil samples from 0-15cm depth were taken on each occassion, spread evenly across the test and control plots. The samples were bulked and homogenised.

Vehicle:

no

Details on preparation and application of test substrate:

Soil samples collected in the field determined the test concentrations. The bulk soil samples had measured corrected concentrations of 31428, 25195, 8145 and 10026ug/g dry weight over time.

Species:

Hordeum vulgare

Plant group:

Monocotyledonae (monocots)

Details on test organisms:

Seeds used

Test type:

other: shoot and root elongation, shoot and root mass

Study type:

laboratory study

Substrate type:

natural soil

Limit test:

no

Total exposure duration:

14 d

Post exposure observation period:

none

Test temperature:

23-28°C

pH:

6.5-7.7

Moisture:

remoistened

Details on test conditions:

Photoperiod - 16L:8D. three replicates of 500cc of remoistened soil were weighed out and placed in a plastic cup. Five healthy, unblemised barley seeds were planted in the cups at a depth of approximately twice the diameter of the seed. After covering the seed, the soil surface was sprayed with deionised water and each cup was placed in an inflated plastic bag. After 14 days growth, emergence, shoot and root elongation and mass were determined. Each plant that had emerged at least 3mm above the soil surface was separated from the soil and washed free of soil. Shoot and root lengths were determined by measuring from the shoot/root interface to the tip of the longest root or shoot. Shoots and roots were separated and dried at 80°C for 48 hours before weighing.

Nominal and measured concentrations:

control and 31428, 25195, 8145 and 10026ug/g dry weight (measured)

Reference substance (positive control):

no

Species:

Hordeum vulgare

Duration:

14 d

Dose descriptor:

LOEC

Effect conc.:

25 195 other: µg/g dry weight

Nominal / measured:

meas. (TWA)

Conc. based on:

test mat.

Basis for effect:

other: shoot length and mass

Species:

Hordeum vulgare

Duration:

14 d

Dose descriptor:

NOEC

Effect conc.:

10 026 other: µg/g dry weight

Nominal / measured:

meas. (TWA)

Conc. based on:

test mat.

Basis for effect:

other: shoot length and mass

Species:

Hordeum vulgare

Duration:

14 d

Dose descriptor:

NOEC

Effect conc.:

31 428 other: µg/g dry weight

Nominal / measured:

meas. (TWA)

Conc. based on:

test mat.

Basis for effect:

other: root length and mass

Details on results:

No effects seen on root length or mass. The authors note that barley plants grown in the field on the exposed soil showed no effects on growth at 10026ug/g but were extremely inhibited at 25195ug/g dry weight.

Results with reference substance (positive control):

not applicable

Reported statistics and error estimates:

No data reported

Validity criteria fulfilled:

no

Remarks:

Non standard test

Conclusions:

The 14 day NOEC shoot growth was 10026ug/g and the LOEC 25195ug/g for barley.

Executive summary:

The 14 day NOEC shoot growth was 10026ug/g and the LOEC 25195ug/g for barley. Although this test does not follow standard guidelines it is well described and includes analytical monitoring of the exposure concentrations.

Description of key information

The key study was a short-term toxicity test on the effects of an analog substance on barley, Hordeum vulgare, following a non-guideline test (Visser, 2003). The 14-d NOEC was reported as 10,026 ug/g d.w.(measured) and the LOEC was reported as 25,195 ug/g d.w.(measured), each based on based on shoot length and mass. A value for EC50 was not reported.