Titanium(4+) ethanolate

Toxicity to terrestrial plants

Administrative data

Endpoint:

toxicity to terrestrial plants: short-term

Type of information:

migrated information: read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

supporting study

Study period:

1985

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

This study is primarily an evaluation of this test methodology as a standard short-term test in environmental monitoring. For ethanol, only the root growth inhibition end-point is reported. Given the high level of detail presented in this test development and evaluation this study is considered to be valid with restrictions. Read-across justification: The substance is hydrolytically unstable. When it comes in contact with water or moisture complete hydrolysis will take place with no significant reaction products other than the particular alcohol and hydrated titanium dioxide. This rapid hydrolysis (hydrolysis half-life < 3 minutes to < 2 hours) is the driving force for the fate and pathways of the substance. The aquatic toxicity testing is considered scientifically unjustified as the substance degrades immediately releasing alcohol and hydrated insoluble titanium dioxides in water. The testing conducted with analogue substances of the category proves that the aquatic toxicity in daphnia and algae studies is similar to the aquatic toxicity of alcohol released to the test water, and the insoluble hydrated titanium oxides precipitated on the bottom of the test vessels. The identification of degradation products from the hydrolysis study conducted for the target substance verifies that there are no impurities in the alcohol released from the target substance, which might change the aquatic toxicity of the target substance compared to the toxicity of the pure alcohol. As there is a mechanistic reasoning to the read-across, the read-across from the degradation product (relevant alcohol) is used to evaluate the aquatic toxicity and the fate and pathways of the target substance in the environment.

Data source

Reference

Reference Type:

publication

Title:

The Allium Test as a Standard in Environmental Monitoring.

Author:

Fiskesjo, G.

Year:

1985

Bibliographic source:

Hereditas 102:99-112.

Materials and methods

Test guideline

Qualifier:

no guideline available

Principles of method if other than guideline:

This study is primarily a proposed new test methodology as a prospective standard short-term test for use in environmental monitoring and for use in toxicity testing of effluents, rivers etc. The test involved growing alliums directly in water containing the test material and measuring adverse effects in terms of root length for the assessment of ethanol

GLP compliance:

no

Test material

Test material information

Constituent 1

Constituent 2

Reference substance name:

Ethanol

EC Number:

200-578-6

EC Name:

Ethanol

Cas Number:

64-17-5

Molecular formula:

C2H6O

IUPAC Name:

ethanol

Details on test material:

- Name of test material (as cited in study report): no data

Sampling and analysis

Analytical monitoring:

no

Test substrate

Vehicle:

yes

Details on preparation and application of test substrate:

- Controls: Yes, water was free of copper ions.
- Chemical name of vehicle (organic solvent, emulsifier or dispersant): water
- Concentration of vehicle in test medium (stock solution and final test solution): 0.1, 1.0, 2.0%
- Evaporation of vehicle before use: no

Test organisms

Species:

Allium cepa

Plant group:

Monocotyledonae (monocots)

Details on test organisms:

- Common name: garden onion
- Plant family: lillaceae
- Variety: 2n=16
- Source of seed: no data
- Prior seed treatment/sterilization: not specified
- Seed storage: under dry conditions (10-20C) and over winter.

Study design

Test type:

seed germination/root elongation toxicity test

Study type:

laboratory study

Substrate type:

other: aqueous medium

Limit test:

no

Total exposure duration:

6 d

Post exposure observation period:

no

Test conditions

Test temperature:

20 deg C

pH:

no data, however, pre-studies showed that species had a wide tolerance to pH range 3.5 to 11.0 indicating that this is not a key parameter.

Moisture:

Bottom of allium placed directly in test liquid (aqueous solution of test substance.)

Details on test conditions:

TEST SYSTEM
- Testing facility: University of Lund, Sweden
- Test container (type, material, size): test tube, 10 cm x 1.5 cm (dia)
- Amount of soil: soil not used
- No. of seeds per container: 1
- No. of plants (retained after thinning): not applicable
- No. of replicates per treatment group: 8
- No. of replicates per control: 8

NUTRIENT MEDIUM (if used)
- Description: plain water plus test substance. water hardness 50-70mg/l (Ca+Mg)

GROWTH CONDITIONS
- Photoperiod: natural diurnal cycle
- Light source: daylight but not direct sunlight
- Day/night temperatures: 20C continuous approx
- Relative humidity (%): not reported

VEHICLE CONTROL PERFORMED: yes

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 0.1, 1.0. 2.0% assumed v/v

EFFECT PARAMETERS MEASURED: Root lengths were measured and compared with controls (%). Root tips were examined turgescence and change of colour.

Nominal and measured concentrations:

0.1, 1.0, 2.0% (assumed v/v)

Reference substance (positive control):

no

Remarks:

Results reported for copper ions

Results and discussion

Effect concentrations

Effect concentrations 1

Species:

Allium cepa

Duration:

6 d

Dose descriptor:

EC50

Effect conc.:

ca. 1.5 other: %

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth

Effect concentrations 2

Species:

Allium cepa

Duration:

6 d

Dose descriptor:

EC10

Effect conc.:

ca. 0.1 other: %

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth

Details on results:

EC50 results are calculated from a linear graph fitted to results (R=0.986). 1.5% v/v equivalent to 11800g/l. 0.1% equivalent to 789mg/l

SEED GERMINATION/ROOT GROWTH
- Percent survival: 100%
- Root length: control length 7.18cm (+/-0.5)
- Root discolouration/malformation: none reported

Results with reference substance (positive control):

Copper ions showed an EC50 of 0.16mg/l

Any other information on results incl. tables

Ethanol concentration   Root length (cm)   %Control
2%                           2.88             33.8
1%                           5.74             67.3
0.1%                         7.34             86.1
Control                      8.52            100

Density of ethanol = 789 g/l

Read-across justifications and data matrices are presented in IUCLID section 13.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Remarks:

No standard validation criteria available but expected response to a toxic positive control

Conclusions:

Based on the literature, 6-d EC50 (rooth growth) of ethanol to Allium cepa is 1.5 % by using the nominal test concentrations.

Executive summary:

In a root growth inhibition test using alliums (allium cepa) proposed for use as a screening test for toxicity assessment of effluents, rivers etc, ethanol was found to have an EC50 value of 11800mg/l and an estimated EC10 of 789mg/l. The dose response curve was relatively shallow and effectively linear over the concentration range examined. Ethanol can be considered as of very low toxicity to plants based on this result.

Synopsis

EC50 (Allium cepa), 6 day = 11800mg/l

EC10 (Allium cepa), 6 day ~ 790mg/l