Tantalum

Short-term toxicity to fish

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2015-03-18 to 2015-06-25

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP study according to OECD Guideline 203

Qualifier:

according to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

- Concentrations: 0 (control) and 100 mg/L
- Sampling method: Daily, before and after renewal, directly from the aquaria (two times 10 ml filled into glass vials)
- Sample storage conditions before analysis: at 5°C +/- 3°C (Additional retain samples at ≤ -18°C)

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: Direct addition and stirring for 24 h, decanting after 3 h of settlement of the precipitations, pH adjustment and filtering through 0.45 µm membrane filter.
- Eluate: Synthetic fish water
- Differential loading: Nominal loading rate of 100 mg/L (limit test)
- Controls: yes
- Evidence of undissolved material (e.g. precipitate, surface film, etc): Precipitation of the test material

Test organisms (species):

Danio rerio (previous name: Brachydanio rerio)

Details on test organisms:

TEST ORGANISM
- Common name: Zebrafish
- Strain: n.a.
- Source: Aquarium Dietzenbach Fischzucht, Dietzenbach, Germany, held at Hydrotox since 2015-01-27
- Length at study initiation (length): 2 - 3 cm
- Feeding during test: no

ACCLIMATION
- Acclimation period: 55 d
- Acclimation conditions (same as test or not): 20.6 - 23.8 °C
- Feeding frequency: Twice every working day
- Health during acclimation (any mortality observed): no abnormal behaviour

Test type:

semi-static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

96 h

Test temperature:

22.4 – 24.8°C

pH:

See Table 2

Dissolved oxygen:

See Table 2

Nominal and measured concentrations:

Nominal test loading rate of 100 mg/L tantalum pentachloride, for measured concentrations see Table 3.

Details on test conditions:

TEST SYSTEM
- Test vessel: 8 L Aquarium
- Material, fill volume: 7000 ml
- Aeration: yes (pump)
- Renewal rate of test solution (frequency/flow rate): daily
- No. of organisms per vessel: 7
- No. of vessels per concentration (replicates): 1
- No. of vessels per control (replicates): 1

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: See table 1
- Culture medium different from test medium: No

OTHER TEST CONDITIONS
- Adjustment of pH: yes, adjusted to 6.5 ± 0.2
- Photoperiod: light/dark cycle of 14:10

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

TEST CONCENTRATIONS
- Spacing factor for test concentrations: none, limit test
- Test concentrations: 100 mg/L

Reference substance (positive control):

not specified

Duration:

96 h

Dose descriptor:

LL50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Duration:

96 h

Dose descriptor:

LL0

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Duration:

96 h

Dose descriptor:

LL100

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

> 1.76 µg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Duration:

96 h

Dose descriptor:

LC0

Effect conc.:

> 1.76 µg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Duration:

96 h

Dose descriptor:

LC100

Effect conc.:

> 1.76 µg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Details on results:

- Behavioural abnormalities: no abnormal behaviour
- Mortality of control: 0
- Other adverse effects control: none
- Abnormal responses: none
- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: agglomeration, solubility changes significantly with only minor changes in pH

Sublethal observations / clinical signs:

Table 2: Results of the acute fish toxicity test, including test parameters.

Treatment	Time [h]	No. of dead fish	O2 [mg/L]		pH		Temp. [°C]
			fresh	aged	fresh	aged
Control	0 – 3	0/7	8.2		7.8		23.6
	3 – 24	0/7		7.7		7.5	23.0 - 24.2
	24 – 48	0/7	8.1	7.1	7.7	7.4	23.6 - 24.7
	48 – 72	0/7	7.8	7.7	7.7	7.4	23.3 - 24.3
	72 – 96	0/7	7.6	7.9	7.8	7.6	22.4 - 24.0
100 mg/L	0 – 6	0/7	6.6		6.5		24.3
	6 – 24	0/7		7.5		6.3	23.8 - 24.6
	24 – 48	0/7	6.4	7.5	6.5	6.3	24.2 - 24.8
	48 – 72	0/7	6.0	7.5	6.5	6.2	23.5 - 24.2
	72 – 96	0/7	5.5	7.9	6.5	6.2	23.1 - 23.8

Table 3: Results of the accompanying chemical analysis.

Nominal loading rate [mg/L]			Control	100 mg/L
Measured Ta concentration [µg/L]	0 h	fresh	< LOQ	6.6
	24 h	aged	< LOQ	1.2
		fresh	< LOQ	0.6
	48 h	aged	< LOQ	< LOQ
		fresh	< LOQ	32.2
	72 h	aged	< LOQ	7.0
		fresh	< LOQ	1.4
	96 h	aged	< LOQ	< LOQ
Geometric mean [µg/L]			< LOQ	1.76

LOQ (Limit of quantification) = 0.5 μg/L

Validity criteria fulfilled:

yes

Conclusions:

In the course of the 96-h limit test with Danio rerio, applying 100 mg/L tantalum pentachloride, no mortalitiy was observed. Therefore, no further testing was carried out. The analytically measured tantalum concentration in solution showed high variability and ranged from below the detection limit of 0.5 µg/L to 32.2 µg/L. This was mainly due to instability in the neutralized medium and agglomeration effects. The chemical analysis revealed a geometric mean of 1.76 µg/L (measured) of the test item in the test media. Hence, the 96-h LL50 (nominal) is > 100 mg/L, the LC50 based on measured concentrations is > 1.76 µg/L.

Executive summary:

In the course of a 96-h limit test with Danio rerio according to OECD guideline 203 (July 1992) applying 100 mg/L tantalum pentachloride under semi-static conditions, no mortality was observed. Therefore, no further testing was carried out.

The analytically measured tantalum concentration in solution showed high variability and ranged from below the detection limit of 0.5 µg/L to 32.2 µg/L. This was mainly due to the fact that small changes in pH caused significant changes in the soluble fraction of the test substance. Additionally, tantalum pentachloride precipitated after adjusting the pH and agglomeration reactions and effects of adsorption to vials and analytical instruments contributed to the varying measured tantalum concentrations in solution. Therefore, effect levels are given as nominal loading rates and mean measured concentrations of tantalum. The chemical analysis revealed a geometric mean of 1.76 µg/L (measured) of the test item in the test media. Hence, the 96-h LL50 (nominal) is > 100 mg/L, the LC50 based on measured concentrations is > 1.76 µg/L. This study is classified as acceptable and satisfies the guideline requirement for a fish acute toxicity study.

Results synopsis

Test organism size (length): 2–3 cm

Test type: Semi-static

Nominal loading rate effect levels:

LLR50 (96h, nominal) > 100 mg/L

LLR0 (96h, nominal) > 100 mg/L

LLR100 (96h, nominal) > 100 mg/L

Measured effect levels (geom. mean):

LC50 (96h, measured) > 1.76 µg/L

LC0 (96h, measured) > 1.76 µg/L

LC100 (96h, measured) > 1.76 µg/L

Endpoint effected: Mortality

Reference 2

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 attached report in section 13 of IUCLID.

Reason / purpose for cross-reference:

read-across source

Duration:

96 h

Dose descriptor:

LL50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Duration:

96 h

Dose descriptor:

LL0

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Duration:

96 h

Dose descriptor:

LL100

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

> 1.76 µg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Duration:

96 h

Dose descriptor:

LC0

Effect conc.:

> 1.76 µg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Duration:

96 h

Dose descriptor:

LC100

Effect conc.:

> 1.76 µg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Details on results:

- Behavioural abnormalities: no abnormal behaviour
- Mortality of control: 0
- Other adverse effects control: none
- Abnormal responses: none
- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: agglomeration, solubility changes significantly with only minor changes in pH

Sublethal observations / clinical signs:

Table 2: Results of the acute fish toxicity test, including test parameters.

Treatment	Time [h]	No. of dead fish	O2 [mg/L]		pH		Temp. [°C]
			fresh	aged	fresh	aged
Control	0 – 3	0/7	8.2		7.8		23.6
	3 – 24	0/7		7.7		7.5	23.0 - 24.2
	24 – 48	0/7	8.1	7.1	7.7	7.4	23.6 - 24.7
	48 – 72	0/7	7.8	7.7	7.7	7.4	23.3 - 24.3
	72 – 96	0/7	7.6	7.9	7.8	7.6	22.4 - 24.0
100 mg/L	0 – 6	0/7	6.6		6.5		24.3
	6 – 24	0/7		7.5		6.3	23.8 - 24.6
	24 – 48	0/7	6.4	7.5	6.5	6.3	24.2 - 24.8
	48 – 72	0/7	6.0	7.5	6.5	6.2	23.5 - 24.2
	72 – 96	0/7	5.5	7.9	6.5	6.2	23.1 - 23.8

Table 3: Results of the accompanying chemical analysis.

Nominal loading rate [mg/L]			Control	100 mg/L
Measured Ta concentration [µg/L]	0 h	fresh	< LOQ	6.6
	24 h	aged	< LOQ	1.2
		fresh	< LOQ	0.6
	48 h	aged	< LOQ	< LOQ
		fresh	< LOQ	32.2
	72 h	aged	< LOQ	7.0
		fresh	< LOQ	1.4
	96 h	aged	< LOQ	< LOQ
Geometric mean [µg/L]			< LOQ	1.76

LOQ (Limit of quantification) = 0.5 μg/L

Validity criteria fulfilled:

yes

Conclusions:

In the course of the 96-h limit test with Danio rerio, applying 100 mg/L tantalum pentachloride, no mortality was observed. Therefore, no further testing was carried out. The analytically measured tantalum concentration in solution showed high variability and ranged from below the detection limit of 0.5 µg/L to 32.2 µg/L. This was mainly due to instability in the neutralized medium and agglomeration effects. The chemical analysis revealed a geometric mean of 1.76 µg/L (measured) of the test item in the test media. Hence, the 96-h LL50 (nominal) is > 100 mg/L, the LC50 based on measured concentrations is > 1.76 µg/L.

Executive summary:

In the course of a 96-h limit test with Danio rerio according to OECD guideline 203 (July 1992) applying 100 mg/L tantalum pentachloride under semi-static conditions, no mortality was observed. Therefore, no further testing was carried out.

The analytically measured tantalum concentration in solution showed high variability and ranged from below the detection limit of 0.5 µg/L to 32.2 µg/L. This was mainly due to the fact that small changes in pH caused significant changes in the soluble fraction of the test substance. Additionally, tantalum pentachloride precipitated after adjusting the pH and agglomeration reactions and effects of adsorption to vials and analytical instruments contributed to the varying measured tantalum concentrations in solution. Therefore, effect levels are given as nominal loading rates and mean measured concentrations of tantalum. The chemical analysis revealed a geometric mean of 1.76 µg/L (measured) of the test item in the test media. Hence, the 96-h LL50 (nominal) is > 100 mg/L, the LC50 based on measured concentrations is > 1.76 µg/L. This study is classified as acceptable and satisfies the guideline requirement for a fish acute toxicity study.

Results synopsis

Test organism size (length): 2–3 cm

Test type: Semi-static

Nominal loading rate effect levels:

LLR50 (96h, nominal) > 100 mg/L

LLR0 (96h, nominal) > 100 mg/L

LLR100 (96h, nominal) > 100 mg/L

Measured effect levels (geom. mean):

LC50 (96h, measured) > 1.76 µg/L

LC0 (96h, measured) > 1.76 µg/L

LC100 (96h, measured) > 1.76 µg/L

Endpoint effected: Mortality

This information is used in a read-across approach in the assessment of the substance to be registered.

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

Description of key information

In the course of the 96-h limit test with Danio rerio, applying 100 mg/L tantalum pentachloride, no mortality was observed. Therefore, no further testing was carried out. The analytically measured tantalum concentration in solution showed high variability and ranged from below the detection limit of 0.5 µg/L to 32.2 µg/L. This was mainly due to instability in the neutralized medium and agglomeration effects. The chemical analysis revealed a geometric mean of 1.76 µg/L (measured) of the test item in the test media. Hence, the 96-h LL50 (nominal) is > 100 mg/L, the LC50 based on measured concentrations is > 1.76 µg/L.

Additional information

According to Annex VIII section 9.1.3, column 2 of the Regulation (EC) No 1907/2006, short-term toxicity tests on fish do not need to be conducted "if, there are mitigating factors indicating that aquatic toxicity is unlikely to occur, for instance if the substance is highly insoluble in water”. As tantalum metal is highly insoluble, see section 4.8 (Fox, 2012), it is not expected to be toxic to fish.

Nevertheless, toxicity data from a read-across source is used to describe the toxicity. The analytically measured tantalum concentrations in the test with TaCl₅ showed high variability and ranged from below LOD (0.5 µg/L) to 32.2 µg/L, with the upper concentration, however, sufficiently covering the water solubility of Ta metal of ≤ 21.3 µg/L. No effects were observed with TaCl and thus no effects are to be expected by Ta metal.

This information is used in a read-across approach in the assessment of the substance to be registered.

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