Titanium carbide

Short-term toxicity to fish

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

short-term toxicity to fish

Type of information:

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

Adequacy of study:

supporting study

Justification for type of information:

Justification for read-across: Due to lower transformation/dissolution results for titanium carbide (the target substance) than titanium dioxide (the source substance), the resulting toxicity potential would also be expected to be lower, so read-across is appropriate. Therefore, the dose descriptors are expected to be sufficiently higher for the target substance, and read-across to the source chemical is adequately protective. For more details refer to the attached description of the read-across approach (see IUCLID section 13.2).

Reason / purpose for cross-reference:

read-across source

Test organisms (species):

Danio rerio (previous name: Brachydanio rerio)

Duration:

48 h

Dose descriptor:

LC50

Effect conc.:

> 10 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks:

adult fish

Key result

Duration:

48 h

Dose descriptor:

LC50

Effect conc.:

> 10 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks:

juvenile fish

Reported statistics and error estimates:

LC50 values were calculated using the trimmed Spearman-Karber method.

Validity criteria fulfilled:

not specified

Conclusions:

No mortality could be observed in adult females and juveniles (fry < 24 h) when exposed to TiO2 nanoparticles in concentrations up to 10 mg/L for 48 h.

Executive summary:

The 48 hr acute toxicity of TiO₂ nanoparticles to adult females and juveniles (fry < 24 h) of Danio rerio (zebrafish) was studied under static conditions. Fish were exposed to TiO₂ at concentrations ranging between 0 (control) and 10 mg/L nominal concentration. Mortality was observed every 12h. 

The 48 hour LC₅₀ was > 10 mg/L (nominal concentration), for both adult female fish and sac fry stage. 

This information is used in a read-across approach in the assessment of the target substance.

For justification of read-across please refer to the attached read-across report (see IUCLID section 13).

Reference 2

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

Meets generally accepted scientific standards, well documented and acceptable for assessment. Justification for read-across: Due to lower transformation/dissolution results for titanium carbide (the target substance) than titanium dioxide (the source substance), the resulting toxicity potential would also be expected to be lower, so read-across is appropriate. Therefore, the dose descriptors are expected to be sufficiently higher for the target substance, and read-across to the source chemical is adequately protective. For more details refer to the attached description of the read-across approach.

Reason / purpose for cross-reference:

reference to same study

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 204 (Fish, Prolonged Toxicity Test: 14-day Study)

Principles of method if other than guideline:

Fish were exposed to TiO2 nanoparticles in concentrations of 0 (control), 0.1, 0.5 and 1.0 mg/L for 14 days. Different biochemical parameters (haematology, blood plasma ion concentrations, gill injury, liver, skinned muscle and brains etc.) as well as mortality and behaviour were measured after 0, 7 and 14 days.

GLP compliance:

not specified

Analytical monitoring:

yes

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: a 10 g TiO2/L stock solution was prepared by dispering the substance in ultrapure water by sonication; stock solution was again sonicated immediately prior to dosing each day.
- Dispersion was confirmed by analytical measurements (transmission electron microscopy, optical methods)
- fish tanks were dosed with 0.2, 1.0 or 2.0 ml of the 10 g/L stock solution to achive test substance concentrations of 0.1, 0.5 and 1.0 mg/L respectively

Test organisms (species):

Oncorhynchus mykiss (previous name: Salmo gairdneri)

Details on test organisms:

TEST ORGANISM
- Common name: Rainbow trout
- Source: Hatchlands Trout Farm, Rattery, Devon
- Age at study initiation (mean and range, SD): juvenile
- Weight at study initiation: 28.1±0.4 g (n = 189)
- Feeding during test: no. except for day 10 (in order to reduce hunger and aggressive behaviour of fish; fish were fed after water change and prior to re-dosing with TiO2)


ACCLIMATION
- Acclimation period: 4 weeks
- Acclimation conditions (same as test or not): flowing, aerated, dechlorinated tap water
- Type and amount of food: commercial trout food ad libitum
- Feeding frequency: not reported.
- Health during acclimation (any mortality observed): no data

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

14 d

Hardness:

50 mg CaCO3/l

Test temperature:

14±1 °C

pH:

7.11±0.01

Dissolved oxygen:

87.0±0.25 %

Salinity:

Not applicable.

Nominal and measured concentrations:

Nominal: 0 (control), 0.1, 0.5 and 1.0 mg/l TiO2.
Measured TiO2 concentrations after dosing the tanks were 95, 98 and 97% of the nominal target values for the 0.1, 0.5 and 1.0 mg TiO2/L treatments, respectively. Before the 12h water change, measured concentrations were 89, 85 and 86% of the nominal values for the 0.1, 0.5 and 1.0 mg TiO2/L treatments, respectively.

Details on test conditions:

TEST SYSTEM
- Test vessel: glass aquaria
- Type (delete if not applicable): open
- Material, size, headspace, fill volume: no data
- Aeration: yes
- Renewal rate of test solution: 80% water change every 12 h; re-dosing after water change
- No. of organisms per vessel: 14
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 3

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: dechlorinated Plymouth tap water
- Na+ = 0.5 mmol/L
- K+ = 0.1 mmol/L
- Ca2+ = 0.4 mmol/L
- Mg2+ = 0.1 mmol/L

OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: 12h:12h light:dark
- Light intensity: no data

EFFECT PARAMETERS MEASURED (with observation intervals if applicable):
Different biochemical parameters (haematology, blood plasma ion concentrations, gill injury, liver, skinned muscle and brains etc.) as well as mortality and behaviour were measured after 0, 7 and 14 days (fish were randomly sampled).

Reference substance (positive control):

no

Duration:

14 d

Dose descriptor:

NOEC

Effect conc.:

1 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Key result

Duration:

14 d

Dose descriptor:

LC50

Effect conc.:

> 1 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Details on results:

1) In any of the concentrations tested during the 14-d exposure of fish, TiO2 nanoparticles did not cause mortality.

2) Results for biochemical endpoints (data not relevant for mortality):
- Haemoglobin, haematocrit, red blood cells, white blood cells, mean erythrocryte haemoglobin content, mean erythrocyte volume, plasma K+:
* 14 d NOEC >= 1 mg/L nominal test mat.
* 14 d EC50 > 1 mg/L nominal test mat.
- other: Plasma Na+:
* 14 d NOEC 0.5 mg/L meas. (initial) test mat.
* 14 d LOEC 1 mg/L meas. (initial) test mat.

3) Behavioural change of some fish at 1 mg/L (loss of positin holding > caused by fatigue or abnormal buoyancy control)

4) significant increase of incidence of oedema in the secondary lamellae from c(TiO2) ≥ 0.1 mg/L, changes in mucocyte morphology, and hyperplasia in the primary lamellae

5) No evidence for clear treatment or time-dependent effects on Ti levels in the gill, liver or muscle

Reported statistics and error estimates:

- Pooled data were analysed with StatGraphics Plus (v5.1).
- Data were checked for kurtosis, skewedness and unequal variance (Bartlett’s test)
- Subsequent ANOVA test for treatment or time effects by ANOVA followed by Fisher’s 95% least-squares difference (95% confidence limits)
- Kruskal–Wallis test (non-parametric data)
- Identification of differences by notched box and whisker plots
- Student’s t-test for determination of differences between pairs of data sets at the end of the experiment

Validity criteria fulfilled:

yes

Remarks:

(when compared to OECD 204 guideline requirements)

Conclusions:

Under the conditions of the test no toxic effects could be observed at the maximum concentration of TiO2 nanoparticle tested. The LC50 is reported to be > 1.0 mg/L.

Executive summary:

A prolonged fish toxicity test similar to OECD 204 was conducted to examine TiO2 nanoparticle toxicity to rainbow trout. Fish were exposed to the test substance for a total duration of 14 days to at concentrations of 0 (control), 0.1, 0.5, and 1.0 mg/L under semi-static conditions.

Mortality based on effects of TiO2 could not be observed at any of the concentrations tested. Thus the LC50 was determined to be > 1.0 mg/L.

Reference 3

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

ASTM Guideline study without detailed documentation.

Reason / purpose for cross-reference:

reference to same study

Qualifier:

according to guideline

Guideline:

other: American Society for Testing and Materials: Standard guide for conducting acute toxicity tests on test materials with fishes, macro invertebrates and amphibians

GLP compliance:

not specified

Analytical monitoring:

no

Vehicle:

no

Details on test solutions:

Dilution water was dechlorinated municipal water, moderately hard.

Test organisms (species):

Danio rerio (previous name: Brachydanio rerio)

Details on test organisms:

TEST ORGANISM
- Common name: zebrafish (wild-type)
- Source: Ekk-Will, Gibsonton, FL, USA
- Maintenance: at the Aquatic Toxicology Laboratory, University of Florida
- Age at study initiation (mean and range, SD): adult females and fry stage (< 24 h)
- Feeding during test. No data

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Hardness:

142±2 mg CacO3/l

Test temperature:

Not reported

pH:

8.2±1

Dissolved oxygen:

8.5-8.9 mg/l

Salinity:

Not applicable.

Nominal and measured concentrations:

Nominal: up to 10 mg/l

Details on test conditions:

TEST SYSTEM FOR ADULT FISH
- Test vessel: large beakers
- Type (delete if not applicable): open
- Material, size, headspace, fill volume: 2 L
- Aeration: yes (gentle)
- No. of organisms per vessel: 4
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 3

TEST SYSTEM FOR JUVENILE FISH (fry, < 24 h)
- Test vessel: exposure in 12-well plates
- Type (delete if not applicable): open
- Material, size, headspace, fill volume: 4 ml
- Aeration: no
- No. of organisms per vessel: 1
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 3

TEST MEDIUM / WATER PARAMETERS
- Filtration: 0.45 µm pore size

OTHER TEST CONDITIONS: no data

EFFECT PARAMETERS MEASURED (with observation intervals if applicable): mortality (adult and juvenile fish)
> Survival of juvenile fish was assessed by direct observation under light microscopy (death = lack of a visible heartbeat for 30 s and lack of response to physical prodding)

Reference substance (positive control):

no

Duration:

48 h

Dose descriptor:

LC50

Effect conc.:

> 10 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks:

adult fish

Key result

Duration:

48 h

Dose descriptor:

LC50

Effect conc.:

> 10 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks:

juvenile fish

Reported statistics and error estimates:

LC50 values were calculated using the trimmed Spearman-Karber method.

Validity criteria fulfilled:

not specified

Conclusions:

No mortalty could be observed in adult females and juveniles (fry < 24 h) when exposed to TiO2 nanoparticles in concetrations up to 10 mg/L for 48 h.

Executive summary:

The 48 hr acute toxicity of TiO2 nanoparticles to adult females and juveniles (fry < 24 h) of Danio rerio (zebrafish) was studied under static conditions. Fish were exposed to TiO2 at concentrations ranging between 0 (control) and 10 mg/L nominal concentration. Mortality was observed every 12h. 

The 48 hour LC₅₀was > 10 mg/L (nominal concentration), for both adult female fish and sac fry stage.

Reference 4

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

According to OECD 203 test guideline without detailed documentation (e.g. no data on water characteristics reported); only one replicate per test substance concentration and control.

Qualifier:

according to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

GLP compliance:

not specified

Analytical monitoring:

no

Vehicle:

no

Test organisms (species):

Oncorhynchus mykiss (previous name: Salmo gairdneri)

Details on test organisms:

TEST ORGANISM
- Common name: O. mykiss
- Strain:
- Source:
- Age at study initiation (mean and range, SD):
- Length at study initiation (length definition, mean, range and SD):
- Weight at study initiation (mean and range, SD):
- Method of breeding:
- Feeding during test
- Food type:
- Amount:
- Frequency:

ACCLIMATION
- Acclimation period:
- Acclimation conditions (same as test or not):
- Type and amount of food:
- Feeding frequency:
- Health during acclimation (any mortality observed):

QUARANTINE (wild caught)
- Duration:
- Health/mortality:

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

96 h

Hardness:

Not reported.

Test temperature:

test with fine TiO2: 12.2 °C (range: 12.1 - 12.3 °C)
test with ultrafine TiO2: 12.2 (range: 12.1 - 12.5 °C)

pH:

Not reported.

Dissolved oxygen:

Not reported.

Salinity:

Not applicable.

Nominal and measured concentrations:

nominal concentrations: 0 (control), 0.1, 1.0, 10, 100 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: no data
- Type (delete if not applicable): open
- Material, size, headspace, fill volume:
- Aeration: no
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 1
- No. of vessels per control (replicates): 1

TEST MEDIUM / WATER PARAMETERS: No details reported.

OTHER TEST CONDITIONS: no data
- Adjustment of pH:
- Photoperiod:
- Light intensity:

EFFECT PARAMETERS MEASURED (with observation intervals if applicable): mortality

Reference substance (positive control):

no

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

fine TiO2

Basis for effect:

mortality (fish)

Key result

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

ultrafine TiO2

Basis for effect:

mortality (fish)

Duration:

96 h

Dose descriptor:

LC10

Effect conc.:

>= 10 - <= 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

fine TiO2

Basis for effect:

mortality (fish)

Details on results:

96-h exposure of rainbow trout to fine or ultrafine TiO2 particle nominal concentrations of 0, 0.1, 1.0, 10, and 100 mg/L resulted in 0, 0, 0, 10, and 10% or 0, 0, 0, 0, and 0% immobility, respectively.

Validity criteria fulfilled:

not specified

Conclusions:

The LC50 values for fine and ultrafine TiO2 for rainbow trout were determined to be > 100 mg/L.

Executive summary:

Fine TiO2 (380 nm) and ultrafine TiO2 (140 nm) was tested in an acute toxicity study using Oncorhynchus mykiss (rainbow trout) as test organisms. Fish were exposed for 96 h. The test was conducted in accordance with OECD Guideline 203. The test substances were used at nominal test concentrations of 0 (control), 0.01, 0.1, 1.0, 10, 100 mg TiO2/L.

The LC50 values for fine and ultrafine TiO2 for rainbow trout were determined to be > 100 mg/L.

Reference 5

Endpoint:

short-term toxicity to fish

Type of information:

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

Adequacy of study:

key study

Justification for type of information:

For details and justification of read-across please refer to the report attached in section 13 of IUCLID.

Reason / purpose for cross-reference:

read-across source

GLP compliance:

not specified

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

fine TiO2

Basis for effect:

mortality (fish)

Key result

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

ultrafine TiO2

Basis for effect:

mortality (fish)

Duration:

96 h

Dose descriptor:

LC10

Effect conc.:

>= 10 - <= 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

fine TiO2

Basis for effect:

mortality (fish)

Details on results:

96-h exposure of rainbow trout to fine or ultrafine TiO2 particle nominal concentrations of 0, 0.1, 1.0, 10, and 100 mg/L resulted in 0, 0, 0, 10, and 10% or 0, 0, 0, 0, and 0% immobility, respectively.

Validity criteria fulfilled:

not specified

Conclusions:

The LC50 values for fine and ultrafine TiO2 for rainbow trout were determined to be > 100 mg/L.

Executive summary:

Fine TiO2 (380 nm) and ultrafine TiO2 (140 nm) was tested in an acute toxicity study using Oncorhynchus mykiss (rainbow trout) as test organisms. Fish were exposed for 96 h. The test was conducted in accordance with OECD Guideline 203. The test substances were used at nominal test concentrations of 0 (control), 0.01, 0.1, 1.0, 10, 100 mg TiO2/L.

The LC50 values for fine and ultrafine TiO2 for rainbow trout were determined to be > 100 mg/L.

This information is used in a read-across approach in the assessment of the target substance.

For justification of read-across please refer to the attached read-across report (see IUCLID section 13).

Reference 6

Endpoint:

short-term toxicity to fish

Type of information:

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

Adequacy of study:

supporting study

Justification for type of information:

Justification for read-across: Due to lower transformation/dissolution results for titanium carbide (the target substance) than titanium dioxide (the source substance), the resulting toxicity potential would also be expected to be lower, so read-across is appropriate. Therefore, the dose descriptors are expected to be sufficiently higher for the target substance, and read-across to the source chemical is adequately protective. For more details refer to the attached description of the read-across approach (see IUCLID section 13.2).

Reason / purpose for cross-reference:

reference to same study

Reason / purpose for cross-reference:

read-across source

Duration:

14 d

Dose descriptor:

NOEC

Effect conc.:

1 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Key result

Duration:

14 d

Dose descriptor:

LC50

Effect conc.:

> 1 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Details on results:

1) In any of the concentrations tested during the 14-d exposure of fish, TiO2 nanoparticles did not cause mortality.

2) Results for biochemical endpoints (data not relevant for mortality):
- Haemoglobin, haematocrit, red blood cells, white blood cells, mean erythrocryte haemoglobin content, mean erythrocyte volume, plasma K+:
* 14 d NOEC >= 1 mg/L nominal test mat.
* 14 d EC50 > 1 mg/L nominal test mat.
- other: Plasma Na+:
* 14 d NOEC 0.5 mg/L meas. (initial) test mat.
* 14 d LOEC 1 mg/L meas. (initial) test mat.

3) Behavioural change of some fish at 1 mg/L (loss of positin holding > caused by fatigue or abnormal buoyancy control)

4) significant increase of incidence of oedema in the secondary lamellae from c(TiO2) ≥ 0.1 mg/L, changes in mucocyte morphology, and hyperplasia in the primary lamellae

5) No evidence for clear treatment or time-dependent effects on Ti levels in the gill, liver or muscle

Reported statistics and error estimates:

- Pooled data were analysed with StatGraphics Plus (v5.1).
- Data were checked for kurtosis, skewedness and unequal variance (Bartlett’s test)
- Subsequent ANOVA test for treatment or time effects by ANOVA followed by Fisher’s 95% least-squares difference (95% confidence limits)
- Kruskal–Wallis test (non-parametric data)
- Identification of differences by notched box and whisker plots
- Student’s t-test for determination of differences between pairs of data sets at the end of the experiment

Validity criteria fulfilled:

yes

Remarks:

(when compared to OECD 204 guideline requirements)

Conclusions:

Under the conditions of the test no toxic effects could be observed at the maximum concentration of TiO2 nanoparticle tested. The LC50 is reported to be > 1.0 mg/L.

Executive summary:

A prolonged fish toxicity test similar to OECD 204 was conducted to examine TiO2 nanoparticle toxicity to rainbow trout. Fish were exposed to the test substance for a total duration of 14 days to at concentrations of 0 (control), 0.1, 0.5, and 1.0 mg/L under semi-static conditions.

 

Mortality based on effects of TiO2 could not be observed at any of the concentrations tested. Thus the LC50 was determined to be > 1.0 mg/L.

 

This information is used in a read-across approach in the assessment of the target substance.

For justification of read-across please refer to the attached read-across report (see IUCLID section 13).

Description of key information

Titanium carbide was not tested for short-term toxicity to fish, and read-across to titanium dioxide was used for this endpoint. 
No deaths were observed at saturation concentration under exposure conditions in acute and prolonged toxicity tests with titanium dioxide; a definitive LC50 could not be determined.

Additional information

Wahrheit et al. (2007) tested fine TiO₂ (380 nm) and ultrafine TiO₂ (140 nm) using rainbow trout as test organisms according to the protocol of OECD guideline 203. Fish were exposed for 96 h at nominal test concentrations up to 100 mg TiO₂/L (both particle sizes). The LC₅₀ values for fine and ultrafine TiO₂ for rainbow trout were determined to be > 100 mg/L.

This result is further supported by Griffitt et al. (2008) who did not observe toxic effects to adult female zebrafish when exposed at nominal concentrations up to 10 mg/L TiO₂ for 48 h.

In addition, TiO₂ did not exhibit toxic effects in rainbow trout when fish were exposed for 14 days at concentrations up to 1 mg/L (Frederici et al., 2007).

Based on lower transformation/dissolution results for titanium carbide (the target substance) than titanium dioxide (the source substance), the resulting toxicity potential would also be expected to be lower. Therefore, the dose descriptors are expected to be sufficiently high for the target substance, and read-across to the source chemical is adequately protective (for more details refer to the attached description of the read-across approach). In fact, (eco-)toxicologically relevant release of Ti ions from titanium carbide is not expected as the concentration of soluble Ti ions was below the method detection limit (< 0.4 µg/L) in the T/D test. Thus, TiC in considered to be practically insoluble, hence release of Ti ions to any ecotoxicologically relevant extent (and potential subsequent formation of soluble and/or insoluble Ti compounds) is not expected. Therefore, any short-term toxic effects to fish are not expected to arise from TiC.