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Short-term toxicity to aquatic invertebrates

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Endpoint:
short-term toxicity to aquatic invertebrates
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
weight of evidence
Study period:
10 September 2012-08 November 2012
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: see 'Remark'
Remarks:
This study was conducted according to OECD guideline 202 (2004) in accordance with GLP. Category & read-across justification: The substance is hydrolytically unstable. When it comes in contact with water or moisture, a 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 the particular alcohol and hydrated insoluble titanium dioxides in water. The testing conducted with analogue substance of the category justifies that the aquatic toxicity in daphnia and algae studies is similar to the aquatic toxicity of the alcohol released to test water as the insoluble hydrated titanium oxide, precipitated on the bottom of the test vessels is lacking bioavailability. The identification of the 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 a conclusion, the read-across approach from analogue category member is used to justify that the testing is scientifically unjustified for the target substance and the read-across from the degradation product (relevant alcohol) can be used to evaluate the aquatic toxicity and the fate and pathways of the target substance.
Justification for type of information:
The substance is hydrolytically unstable. When it comes in contact with water or moisture, a 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 the particular alcohol and hydrated insoluble titanium dioxides in water.
The testing conducted with analogue substance of the category justifies that the aquatic toxicity in daphnia and algae studies is similar to the aquatic toxicity of the alcohol released to test water as the insoluble hydrated titanium oxide, precipitated on the bottom of the test vessels; lacking bioavailability. The identification of the 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.
Reason / purpose:
read-across source
Qualifier:
according to
Guideline:
OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)
Qualifier:
according to
Guideline:
ISO 6341 (Water quality - Determination of the Inhibition of the Mobility of Daphnia magna Straus (Cladocera, Crustacea))
Qualifier:
according to
Guideline:
EU Method C.2 (Acute Toxicity for Daphnia)
GLP compliance:
yes
Analytical monitoring:
yes
Details on sampling:
- Concentrations: between 0.10; 1.0; 10 and 100 % of the filtrate prepared at 100 mg Titanium tetra(octanolate), branched and linear per litre. Test concentrations measured against the hydrolysis product octyl alcohol isomers. Substance was hydrolytically unstable releasing octyl alcohol isomers. Additionally when stock solutions were prepared a white precipate was formed, which was hydrated titaniumdioxide.

- Sampling method: samples for possible(duplicates) were taken from all test concentrations and the control
Frequency at t=0 h and t=48 h
Volume 1 ml from the approximate centre of the test vessels
Storage Samples were stored in a freezer until analysis.

At the end of the exposure period, the replicates were pooled at each concentration before sampling.

- Sample storage conditions before analysis: The samples were stored in the freezer (≤ -15°C)
Vehicle:
no
Details on test solutions:
PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Eluate: Dilution water
- Differential loading: 0, 10, 18, 32, 56 and 100% of a 0.45 µm filtered solution prepared at 100 mg 100 mg Titanium tetra(octanolate), branched and linear per litre.
- Controls: Test medium without test substance or other additives

The test substance was not completely soluble in test medium at the loading rate initially prepared. Preparation of test solutions started with a loading rate of 100 mg/l applying a 15 to 16-minute period of magnetic stirring that was sufficient to ensure complete hydrolysis to octyl alcohol isomers. The obtained clear and colourless solution containing precipitate and a floating layer of undissolved material was filtered through a 0.45 µm membrane filter (rc55, Whatman) and used as the highest test concentration. The lower test concentrations were prepared by subsequent dilutions of the filtrate in test medium. The final test solutions were all clear and colourless.


Test organisms (species):
Daphnia magna
Details on test organisms:
TEST ORGANISM
- Common name: Daphnia magna (Crustacea, cladocera) Straus, 1820
- Source: In-house laboratory culture with a known history.
- Age at study initiation (mean and range, SD): age of < 24 hours, from parental daphnoids of more than two weeks old.
- Renewal of the cultures: After 7 days of cultivation half of the medium twice a week
- Method of breeding: With new born daphnids, i.e less than 3 days old, by placing about 250 of them into 5 litres of medium in an all glass culture vessel.
- Food type: algae
- Frequency: daily

ACCLIMATION
- Acclimation period: Adult daphnia were maintained in glass vessels containing 5 litres water in a temperature controlled room at approximately 18-20°C. The lightening cycle was controlled to give a 16 hours photoperiod daily.
- Feeding: Daily suspension of fresh water algae
- Health during acclimation (any mortality observed): The diet and diluent water are considered not to contain any containment that would affect the integrity or outcome of the study.
Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
48 h
Remarks on exposure duration:
24 h exposure was also recorded
Post exposure observation period:
at 24 h and 48 h
Hardness:
180 mg/l expressed as CaCO3
Test temperature:
The temperature of the test medium was 19.3°C at the start of the test. The temperature continuously measured in a temperature control vessel varied between 18.8 and 19.4°C during the test.
pH:
6.0-8.5, not varying by more than 1.5 unit
Dissolved oxygen:
≥3 mg/l at the end of the test
Nominal and measured concentrations:
10, 18, 32, 56 and 100% of a 0.45 µm filtered solution prepared at 100 mg/l.

As the test substance is hydrolytically unstable, the concentrations of the hydrolysis products being octyl alcohol isomers were measured.

The concentrations measured from the solution 10 and 100 % of the filtrate. The concentration of octyl alcohol isomers was 4.2 and 52 mg/l at the start and remained constant during the exposure period (92-104% of initial).

The mean measured concentrations at the start of the test were 17, 31 and 56 mg/l in test groups representing 32, 56 and 100% of the test item filtrate prepared at 100 mg/l. The actual concentrations were between 115 and 122% of initial at the end of the test. The average exposure concentrations were calculated to be 19, 34 and 60 mg/l, respectively. Note that these concentrations should be regarded as indicative.
Details on test conditions:
TEST SYSTEM
- Test vessel: all glass
- Material, size, headspace, fill volume: 100 ml
- Aeration: no aeration
- No. of organisms per vessel: 5 per vessel containing 80 ml of solution
- No. of vessels per concentration: 4
- No. of vessels per control: 4


TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: tap water purified by Reverse Osmosis (RO-water, GEON Waterbehandeling, Berkel-Enschot, The Netherlands)
- Culture medium different from test medium: Adjusted ISO medium
a) CaCl2.2H2O 211.5 mg/l
b) MgSO4.7H2O 88.8 mg/l
c) NaHCO3 46.7 mg/l
d) KCl 4.2 mg/l

OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: 16 h photoperiod daily

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
Immobility (including mortality) at 24 hours and at 48 hours.
pH and dissolved oxygen: at the beginning and at the end of the test, for the highest concentration and the control.
Temperature of medium: continuously in a temperature control vessel, beginning at the start of the test.

TEST CONCENTRATIONS

- Range finding study:
A combined limit/range-finding test was performed. Twenty daphnids per concentration (four replicates, 5 daphnids per vessel) were exposed to a control and an undiluted filtrate prepared at 100 mg/l. Test procedure and conditions were similar to those applied in the final test with the following exceptions:
• Ten daphnids per concentration (in duplicate, 5 per vessel) were exposed to 0.1, 1.0 and 10% of the filtrate.
• Dissolved oxygen concentrations and pH were only measured in the control and the highest test concentration.
• Singular samples for the determination of the exposure concentrations were taken.

- Test concentrations: 10, 18, 32, 56 and 100% of a 0.45 µm filtered solution prepared at 100 mg/l.

- Results used to determine the conditions for the definitive study:
The responses recorded during the combined limit/range-finding test: No immobility was observed in the control and in 0.1, 1.0 and 10% of the filtrate during the whole exposure period. In the undiluted filtrate 75% of the daphnids were immobilised at the end of the test.

As the test sample is highly hydrolytically unstable the samples taken from 10 and 100 % of the filtrate were analysed. The concentration of octyl alcohol isomers was 4.2 and 52 mg/l at the start and remained constant during the exposure period (92-104% of initial).

The control group were maintained under identical conditions to the test groups.
Reference substance (positive control):
yes
Remarks:
Potassium dichromate
Duration:
48 h
Dose descriptor:
EC50
Effect conc.:
ca. 41 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
other: Hydrolysis product: Octyl alcohol isomers (CAS no 68526-83-0)
Basis for effect:
mobility
Remarks on result:
other: based on average exposure concentration (95% confidence interval between 37 and 49 mg/l).
Duration:
48 h
Dose descriptor:
EC50
Effect conc.:
ca. 74 mg/L
Nominal / measured:
estimated
Conc. based on:
test mat.
Basis for effect:
mobility
Remarks:
Represents test item conc. between 56 % to 100 % which corresponds measured conc. of octyl alcohol isomers between 34 mg/l and 60 mg/l.
Details on results:
- Behavioural abnormalities: In the highest concentration test substance was observed on daphnia bodies. This can suggest that the observed effect could be partly caused by mechanical hampering. The toxic effect cannot be excluded as in the combined limit/range-finding test no test substance was observed on immobilised daphnias.
- Observations on body length and weight: not reported
- Other biological observations: not observed
- Mortality of control: The responses recorded in this test allowed for reliable determination of an EC50. No immobility was observed in the control and the three lowest concentrations. In the two highest concentration the group mean effects were 15 and 90% in 56 and 100% of the filtrate, respectively, corresponding to the average concentrations of 34 and 60 mg octyl alcohol isomers per litre.
- Other adverse effects control: not reported
- Abnormal responses: not reported
- Any observations (eg. precipitation) that might cause a difference between measured and nominal values: The test item rapidly hydrolyses in the aqueous test media forming octyl alcohol isomers and hydrated titanium dioxide, with the hydrated titanium dioxide precipitating out of the solution. Given the rapid hydrolysis of the test item it was considered that any toxicity would be due to the presence of octyl alcohol and not parent test item. The test concentrations were monitored by analysis of the test samples for octyl alcohol alcohol only.
- Effect concentrations exceeding solubility of substance in test medium: The test preparations were observed to be clear and colourless solutions.
Results with reference substance (positive control):
Daphnia were exposed for a maximum of 48 hours to K2Cr2O7 concentrations of 0.10, 0.18, 0.32, 0.56, 1.0 and 1.8 mg/l and to a blank control. Twenty daphnia were exposed per concentration.
The 24h-EC50 was 0.50 mg/l with a 95% confidence interval between 0.44 and 0.57 mg/l.
The 48h-EC50 was 0.30 mg/l with a 95% confidence interval between 0.28 and 0.35 mg/l.
Reported statistics and error estimates:
Determination of the average exposure concentrations:
The average exposure concentrations were calculated as, being the geometric means of the concentrations of octyl alcohol isomers measured in the samples taken at the start (Ct=0) and the end of the test (Ct=48).
The EC50-value was calculated at 24 and 48 hours of exposure from the probits of the percentages of affected daphnids and the logarithms of the corresponding average exposure concentrations of octyl alcohol isomers using the maximum likelihood estimation method (Finney, D.J., 1971: Probit analysis, Cambridge University Press, Cambridge, U.K., 3rd edition).

Combined limit/range-finding test

Table1 shows the responses recorded during the combined limit/range-finding test. No immobility was observed in the control and in 0.1, 1.0 and 10% of the filtrate during the whole exposure period. In the undiluted filtrate 75% of the daphnids were immobilised at the end of the test. 

All test conditions were maintained within the limits prescribed by the protocol.

Table1 Incidence of immobility in the combined limit/range-finding test

Test substance1

% of filtrate

prep. at 100 mg/l

Vessel number

 

Number

Daphnia

exposed

Response at 24 h

Response at 48 h

 

number

Total

%

 

number

Total

%

control

 A

 B

C

D

5

5

5

5

0

0

0

0

0

0

0

0

0

0

0.10

 A

 B

5

4

0

0

0

0

0

0

1.0

 A

 B

5

5

0

0

0

0

0

0

10 (4.2)

 A

 B

5

5

0

0

0

0

0

0

100 (52)

 A

 B

C

D

5

6

5

5

3

1

3

3

50

4

3

4

4

75

1.Titanium tetra(octanolate), branched and linear

() – initially measured concentration of octyl alcohol isomers (mg/l)

Final test

Immobility

Table2 shows the responses recorded during the final test.The responses recorded in this test allowed for reliable determination of an EC50

Table2  Acute immobilisation of daphnids after 24 and 48 hours in the final test

Test substance1

% of filtrate

prep. at 100 mg/l

Vessel

number

 

Number

Daphnia

exposed

Response at 24 h

Response at 48 h

 

number

Total

%

 

number

Total

%

control

 A

 B

C

D

5

5

5

5

0

0

0

0

0

 

0

0

0

0

0

 

10

 A

 B

C

D

5

6

5

5

0

0

0

0

0

 

0

0

0

0

0

 

18

 A

 B

C

D

5

6

5

5

0

0

0

0

0

 

0

0

0

0

0

 

32 (19)

 A

 B

C

D

5

6

5

5

0

0

0

0

0

 

0

0

0

0

0

 

56 (34)

 A

 B

C

D

5

6

5

5

0

0

0 [4]

0 [2]

0

 

0

0

1 [1]

3 [2]

15

100 (60)

 

 A

 B

C

D

5

6

5

5

3 [2]

1

1 [1]

3

40

4

5

4

5

90

1. Titanium tetra(octanolate), branched and linear

( ) average exposure concentrations of octyl alcohol isomers (mg/l).

[ ] between brackets: number of daphnia observed trapped at the surface of the test solutions. These organisms were reimmersed into the respective solutions before recording of mobility.

Analytical data

Concentrations of octyl alcohol isomersin test medium - combined limit/range-finding test

Time of sampling


[hours]

Date of sampling


[dd-mm-yy]

Date of analysis1


[dd-mm-yy]

Percentage of filtrate2


[%]

Analysed concentrationoctyl alcohol isomers[mg/l]

Relative to
initial

 

[%]

 

 

 

 

 

 

0

10-09-12

25-09-12

10

4.24

 

 

 

 

100

52.2

 

48

12-09-12

25-09-12

10

4.42

104

 

 

 

100

47.8

92

1          Samples were stored in the freezer (≤ -15°C) until the day of analysis.

2          Percentage of a filtered test solution prepared at a test substance loading rate of 100 mg/l.

 Concentrations ofoctyl alcohol isomersin test medium - final test

Time of sampling


[hours]

Date of sampling


[dd-mm-yy]

Date of analysis1


[dd-mm-yy]

Percentage of filtrate2


[%]

Analysed concentrationoctyl alcohol isomers
[mg/l]

Relative to
initial

 

[%]

 

 

 

 

 

 

0

06-11-12

08-11-12

0

< 0.7

 

 

 

 

0

< 0.7

 

 

 

 

32

18.8

 

 

 

 

32

16.1

 

 

 

 

56

29.6

 

 

 

 

56

31.9

 

 

 

 

100

52.9

 

 

 

 

100

58.6

 

48

08-11-12

08-11-12

0

< 0.7

 

 

 

 

0

< 0.7

 

 

 

 

32

22.7

130

 

 

 

32

19.1

110

 

 

 

56

40.5

132

 

 

 

56

34.8

113

 

 

 

100

56.3

101

 

 

 

100

71.5

128

1          Samples were stored in the freezer (≤ -15°C) until the day of analysis.

2          Percentage of a filtered test solution prepared at a test substance loading rate of 100 mg/l.

Validity criteria fulfilled:
yes
Remarks:
1.In the control, no daphnids became immobilised. 2.The oxygen concentration at the end of the test was ≥3 mg/l in control and test vessels.
Conclusions:
48-h EC50 (immobilisation) to Daphnia magna was measured using OECD 202 in accordance with GLP. As the test substance hydrolyses during testing releasing alcohol and hydrated titanium dioxide in water, the test concentrations were measured based on the released octyl alcohol isomers. Test substance did not induce acute immobilization of Daphnia magna at an average exposure concentration of 19 mg octyl alcohol isomers per litre, which represented 32 % of a filtrate prepared at 100 mg Titanium tetra(octanolate), branched and linear per litre, after 48 hours of exposure.

The 48h-EC50; 41 mg octyl alcohol isomers /l based on average measured exposure concentration (95% confidence interval between 37 and 49 mg/l). This represents an approximate test item concentration of 74 mg/l.
Executive summary:

This read-across substance is an analogue substance of the target substance (Titanium tetrakis(2 -ethylhexanolate) in the category of highly water reactive titanates. It contains commercial solvent (alcohols C7 -9-iso, C8-rich, CAS no 68526 -83 -0). This solvent consists mainly of isooctanol (93 %), which is similar to the 2 -ethylhexanol released from the target substance. This data is used as a weight of evidence to justify that all the organometallic titanates grouped into this category hydrolyse during toxicity testing, and therefore the toxicity is related to the toxicity of the alcohol released from the substance.

The acute toxicity test performed for this substance identifies that the intrinsic properties of this substance are related to the degradation products due to the rapid hydrolysis which takes place immediately after test substance is introduced to water solution.

This toxicity study is classified as reliable and satisfies the guideline requirements for the acute invertebrate toxicity study. It is used as part of a weight of evidence to evaluate the toxicity of the target substance titanium tetrakis(2 -ethyxanolate).

Endpoint:
short-term toxicity to aquatic invertebrates
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: see 'Remark'
Remarks:
Comparable to GLP guideline study. 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.
Justification for type of information:
The substance is hydrolytically unstable. When it comes in contact with water or moisture, a 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 the particular alcohol and hydrated insoluble titanium dioxides in water.
The testing conducted with analogue substance of the category justifies that the aquatic toxicity in daphnia and algae studies is similar to the aquatic toxicity of the alcohol released to test water as the insoluble hydrated titanium oxide, precipitated on the bottom of the test vessels; lacking bioavailability. The identification of the 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.
Reason / purpose:
read-across source
Qualifier:
according to
Guideline:
EU Method C.2 (Acute Toxicity for Daphnia)
Version / remarks:
Cited as Directive 84/449/EEC, C.2 (Acute toxicity for Daphnia)
GLP compliance:
yes
Analytical monitoring:
no
Details on test solutions:
PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: preparation of a stock solution, and further dilution, using synthetic drinking water
- Synthetic drinking water: sum of Ca and Mg: 2.5 mM. Ratio Ca:Mg = 4:1; ratio Na:K = 10:1.
- Controls: negative controls: synthetic drinking water. Positive controls: potassium dichromate at 0.9 and 1.9 mg/l.
- Concentrations of test material: 28, 40, 56, 80, 110, 160, 220, 320, and 440 mg/l.
- Chemical name of vehicle (organic solvent, emulsifier or dispersant): none used.
- Evidence of undissolved material (e.g. precipitate, surface film, etc): none.
Test organisms (species):
Daphnia magna
Details on test organisms:
TEST ORGANISM
- Common name: Daphnia magna Straus
- Strain: IRCHA
- Source: own breed
- Age at study initiation (mean and range, SD): <12 hours
- Method of breeding: parental animals were grown on M4-medium in 1-L beakers. Animals were fed daily (Scenedesmus subspicatus). Every 2-3 days the water was changed. Young animals were isolated every 4-5 weeks and used for further breeding.
- Feeding during test: no

ACCLIMATION
- Acclimation period: no
Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
48 h
Hardness:
sum of Ca and Mg: 2.5 mM
Test temperature:
20 +/- 1°C
pH:
7.2 - 7.5 at initiation
Dissolved oxygen:
7.4 - 8.3 mg/l at initiation
Nominal and measured concentrations:
Nominal concentrations of test material: 28, 40, 56, 80, 110, 160, 220, 320, and 440 mg/l.
Analytical concentrations: not measured
Details on test conditions:
EST SYSTEM
- Test vessel:
- Type (delete if not applicable): closed
- Material, size, headspace, fill volume: glass, fill volume 10 mL
- Aeration: none
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 1 (20 animals/dose level)
- No. of vessels per control (replicates): 1 (20 animals/dose level)
- No. of vessels per vehicle control (replicates): n.a.
- Biomass loading rate: 2 ml test solution/animal


TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: synthetic water
- Ca/Mg ratio: 4:1
- Conductivity:
- Culture medium different from test medium: no
- Intervals of water quality measurement: 48 h


OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: test was conducted in the dark


EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : immobilisation; recorded at 24 and 48 h after initiation


TEST CONCENTRATIONS
- Spacing factor for test concentrations: 1.4
- Range finding study: none reported
Reference substance (positive control):
yes
Remarks:
Potassium dichromate, 0.9 and 1.9 mg/l
Duration:
48 h
Dose descriptor:
EC50
Effect conc.:
39 mg/L
Basis for effect:
mobility
Details on results:
Immobilisation was complete at 80 mg/L at both 24 and 48 h.
The EC50-values were graphically interpolated from the effects seen at 40 and 56 mg/L:
EC50 (24 h) = 49 mg/L
EC50 (48 h) = 39 mg/L


Results with reference substance (positive control):
Immobilisation after 24 h:
Potassium dichromate 0.9 mg/l: 15%
Potassium dichromate 1.9 mg/l: 50%

Test concentration

[mg/L]

24 h

48 h

number

%

number

%

mobile

immobile

immobile

mobile

immobile

immobile

0

20

0

0

18

1

5.3

28

20

0

0

19

1

5

40

19

1

5

8

12

60

56

3

16

84.2

1

18

94.7

80

0

20

100

0

20

100

110

0

20

100

0

20

100

160

0

20

100

0

20

100

220

0

20

100

0

20

100

320

0

20

100

0

20

100

440

0

20

100

0

20

100

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

Validity criteria fulfilled:
yes
Conclusions:
The 48-h EC50 (immobilisation) of 2-Ethylhexanol to daphnia magna is 39 mg/L. the study test was conducted according EEC 84/449, C.2 ( i.e. similar to OECD test guideline 202) in accordance with GLP.
Endpoint:
short-term toxicity to aquatic invertebrates
Adequacy of study:
other information
Justification for data waiving:
other:

Description of key information

Testing is not scientifically justified as this substance is hydrolytically unstable. The results (48-h LC50) of the structurally similairdecomposition product 2 -ethylhexanol and the analogue categy member (titanium tetra(octanolate), branched and linear) are used as a key value.

Key value for chemical safety assessment

EC50/LC50 for freshwater invertebrates:
40 mg/L

Additional information

When this substance comes in contact with water or moisture, a complete hydrolysis will take place with no significant reaction products other than EHD and hydrated titanium dioxide (half-life < 10 minutes, Brekelmans M.J.C. 2013). The structurally similair hydrolysis product, 2 -ethylhexanol, is readily biodegradable and not persistent ( log Kow value 2.9 < 4). Therefore, the testing was considered unnecessary. The CSA indicates that toxicity of this substance is similar to the main degradation product 2-ethylhexanol based on the weight of evidence which uses the studies conducted for the analogue category member and the degradation product (2 -ethylhexanol).

Key studies (short-term toxicity to daphnia and algae) conducted for the analogue category member (titanium tetra(octanolate), branched and linear, CAS 68526 -83 -0) justify that these organometallic titanates hydrolyse during toxicity testing and the aquatic toxicity is similar to the alcohol released in water. Category and read-across justifications are presented in the annexes of the CSR.

This read-across substance is an analogue substance grouped together with the target substance into the category of highly water reactive titanates. It contains commercial solvent (alcohols C7 -9-iso, C8-rich, CAS no 68526 -83 -0). This solvent contains 93 % of isooctanol being also an analogue substance with 2 -ethylhexanol; an isomer of octyl alcohol.

The 48-h EC50 (immobilisation) to Daphnia magna measured by using OECD 202 in accordance with GLP was conducted for the analogue category member. As the test substance hydrolysed during testing, the test concentrations were measured based on the released octyl alcohol isomers. Test substance did not induce acute immobilization of D.magna at an average exposure concentration of 19 mg octyl alcohol isomers per litre. Based on this study results, the 48h-EC50 was 41 mg octyl alcohol isomers /l based on average measured exposure concentration (95% confidence interval between 37 and 49 mg/l).

In addition, a reliable 48-h EC50 (immobilisation) of 2-ethylhexanol to Daphnia magna is 39 mg/L. This study was conducted according EEC 84/449, C.2 ( i.e. similar to OECD test guideline 202) in accordance with GLP (Scholz 1991).

Based on the weight of evidence approach, the results of the analogue category member and the degradation products are very similar. Therefore, the key value of 40 mg/l for CSA is obtained as an average of these results.