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Short-term toxicity to aquatic invertebrates

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Endpoint:
short-term toxicity to aquatic invertebrates
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2014-11-10 to 2015-06-29
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: GLP study according to OECD Guideline 202 (April 2004).
Qualifier:
according to
Guideline:
OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)
Deviations:
no
GLP compliance:
yes (incl. certificate)
Specific details on test material used for the study:
Details on properties of test surrogate or analogue material (migrated information):
PHYSICO-CHEMICAL PROPERTIES
- Stability in water: reacts violently with water
Analytical monitoring:
yes
Details on sampling:
- Concentrations: 0 (Control), 593, 1333 and 3000 mg/L (sampling of 20 mL at 0h, before and after renewal of the test solutions and after 48h)
- Sampling method: 20 mL removed, stablized with 200 µL of nitric acid
- Sample storage conditions before analysis: Stored at 5 ± 3 °C (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
- Eluate: Synthetic water
- Controls: Synthetic water
Test organisms (species):
Daphnia magna
Details on test organisms:
TEST ORGANISM
- Common name: Daphnia magna Straus
- Source: Clone breeding of the German Federal Environmental Agency, Department V 3.2, Berlin
- Age at study initiation (mean and range, SD): < 24 h

BREEDING
- Food type: Desmodesmus subspicatus
- Amount: Daily 0.1 mg C per daphnid
- Light/dark cycle: 16/8 h
- Temperature: 20 +/- 2°C
- Housing: 10 animals/ 200 ml
- Medium: M4 (ELENDT), transfer twice per week into fresh medium
Test type:
semi-static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
48 h
Test temperature:
20.3 - 20.8 °C
pH:
See Tables 2 and 3.
Dissolved oxygen:
See Table 3.
Salinity:
Neutralization with NaOH of the media was needed due to the strong acidic reaction of tantalum pentachloride in water. The resulting NaCl concentration in the neutralized media was 2.34 g/L.
Nominal and measured concentrations:
See Table 1.
Details on test conditions:
TEST SYSTEM
- Test vessel: Glass beakers, 50 ml
- Fill volume: 20 ml
- Renewal rate of test solution: Once, after 24 h
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 4

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Synthetic water

OTHER TEST CONDITIONS
- Adjustment of pH: yes
- Photoperiod: 16/8 h

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Mobility after 24 and 48 h

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 1.5
- Range finding study. yes
- Test concentrations: 0 (Control), 593, 889, 1333, 2000 and 3000 mg/L
Reference substance (positive control):
yes
Remarks:
Potassium dichromate
Duration:
24 h
Dose descriptor:
EL10
Effect conc.:
2 380 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mobility
Duration:
48 h
Dose descriptor:
EL10
Effect conc.:
688 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mobility
Duration:
48 h
Dose descriptor:
EL50
Effect conc.:
3 086 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mobility
Duration:
48 h
Dose descriptor:
other: EL20
Effect conc.:
1 152 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mobility
Duration:
24 h
Dose descriptor:
LOELR
Effect conc.:
> 3 000 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mobility
Duration:
48 h
Dose descriptor:
LOELR
Effect conc.:
3 000 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mobility
Duration:
24 h
Dose descriptor:
NOELR
Effect conc.:
>= 2 000 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mobility
Duration:
48 h
Dose descriptor:
NOELR
Effect conc.:
2 000 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mobility
Details on results:
After pH adjustment, the measured Ta5+ concentrations were low and showed high variability. Therefore, no concentration-response relationship could be established. Concentrations of the test sample varied due to precipitation, agglomeration and adsorption reactions. In addition, slight changes in pH had profound impact on the test concentrations. Observed immobilization effects may therefore rather predominantly refer to elevated NaCl, concentrations originated from neutralization, than released Ta5+ ions. Hypothetical Ta5+ related effects cannot be distinguished from NaCl induced inhibition in the conducted test. Therefore, only nominal effect levels were calculated.

- Mortality of control: 0
Results with reference substance (positive control):
- EC50 (24 h): 1.97 mg/L
- EC50 (48 h): < 1.25 mg/L

Table 3: Results of the Daphnia immobilization test after 24 and 48 h.

Nominal loading rate

[mg/L]

Volume test solution

[ml]

Time

[h]

Number immobile/ daphnids inserted

Sum immobile

Sum inserted

Immobilization

[%]

Oxygen

[mg/L]

pH

1

2

3

4

Initial

End

Initial

End

593

20

24

0/5

0/5

0/5

0/5

0

20

0

6.0

8.0

6.5

7.2

48

0/5

0/5

1/5

0/5

1

20

5

6.9

8.1

6.2

889

20

24

0/5

1/5

1/5

0/5

2

20

10

6.0

8.0

6.5

7.1

48

3/5

1/5

1/5

2/5

7

20

35

6.9

8.3

6.1

1333

20

24

0/5

0/5

0/5

0/5

0

20

0

6.4

8.1

6.5

7.2

48

0/5

0/5

0/5

0/5

0

20

0

6.9

8.2

6.2

2000

20

24

0/5

0/5

0/5

0/5

0

20

0

5.9

8.0

6.5

7.2

48

0/5

1/5

2/5

3/5

6

20

30

6.8

8.3

6.2

3000

20

24

1/5

1/5

1/5

1/5

4

20

20

6.2

8.1

6.5

7.1

48

2/5

3/5

4/5

3/5

12

20

60

6.8

8.3

6.1

Control

24

0/5

0/5

0/5

0/5

0

20

0

7.2

7.4

6.9

7.4

48

0/5

0/5

0/5

0/5

0

20

0

7.4

7.9

7.3

7.3

Table 4: Results of the chemical analysis of the control and the test loading rates 593, 1333 and 3000 mg/L.

Sample

NC

A

C

E

Nominal loading rate [mg/L]

0

593

1333

3000

Measured concentration [µg/L]

Before chemical digestion

0 h

< LOQ

< LOQ

1.44

8.36

24 h (aged)

< LOQ

< LOQ

< LOQ

1.67

24 h (fresh)

< LOQ

0.65

< LOQ

1.12

48 h

-

< LOQ

0.42

1.05

After chemical digestion

0 h

< LOQ

1.0

144

58.9

24 h (aged)

< LOQ

< LOQ

76.5

19.1

24 h (fresh)

< LOQ

5.82

2.91

4.09

48 h

< LOQ

2.53

15.4

6.93

LOQ (Limit of quantification) = 0.5 μg/L

Validity criteria fulfilled:
yes
Conclusions:
For the conducted semi-static acute immobilization test with Daphnia magna, applying nominal concentrations of 593 to 3000 mg/L tantalum pentachloride, nominal effect levels were calculated: 24h EL10 (nominal): 2380 mg/L (95%-CI: n.d.); 24h LOELR: > 3000 mg/L; 24h NOELR: ≥ 2000 mg/L; 48 h EL50 (nominal): 3086 mg/L (95%-CI: n.d.); 48h EL20 (nominal): 1152 mg/L (95%-CI: n.d.); 48h EL10 (nominal): 688 mg/L (95%-CI: n.d.); 48h LOELR: 3000 mg/L; 48h NOELR: 2000 mg/L. Due to methodological difficulties, it was not possible to calculate effect concentrations based on measured concentrations. Hence, values are reported based on the nominal loading rates.
Executive summary:

The 48 h acute toxicity of tantalum pentachloride to Daphnia magna Straus was studied under semi-static conditions. Daphnids were exposed to a control containing no test substance and tantalum pentachloride at nominal loading rates of 593, 889, 1333, 2000 and 3000 mg/L for 48 h. Immobilization was observed daily. Due to highly variable Ta5+ concentrations in solution, effect concentrations were based on nominal loading rates. The 48-hour EL50 was 3086 mg/L. The 48-h NOELR based on immobilization was 2000 mg/L and the LOELR was 3000 mg/L.

This study is classified as acceptable and satisfies the guideline requirements for an acute toxicity study with freshwater invertebrates.

However, it was not possible to determine effect levels based on measured effective test substance concentrations. After pH adjustment the measured Ta5+ concentrations were low and showed high variability. Measured values of Ta5+ ranged from < LOQ to 8.36 µg/L before chemical digestion of samples and from < LOQ to 144 µg/L after chemical digestion of samples. Therefore, no concentration-response relationship could be established. Concentrations of the test sample varied due to precipitation, agglomeration and adsorption reactions. In addition, slight changes in pH had profound impact on the test concentrations. Observed immobilization effects may therefore rather predominantly refer to elevated NaCl concentrations, originated from neutralization, than released Ta5+ ions. Reported EC50 values for sodium chloride vary but may be as low as 874 mg/L (ECHA registry for sodium chloride). Due to a concentration of approximately 2.34 g/L NaCl, present at the highest loading rate of 3000 mg/L test substance, and the sensitivity of D.magna to salinity, any hypothetical Ta5+ related effects cannot be distinguished from NaCl induced inhibition in the conducted test.

Endpoint:
short-term toxicity to aquatic invertebrates
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Justification for type of information:
This information is used in a read-across approach in the assessment of the substance to be registered.

Reason / purpose:
read-across source
Duration:
24 h
Dose descriptor:
EL10
Effect conc.:
2 380 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mobility
Duration:
48 h
Dose descriptor:
EL10
Effect conc.:
688 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mobility
Duration:
48 h
Dose descriptor:
EL50
Effect conc.:
3 086 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mobility
Duration:
48 h
Dose descriptor:
other: EL20
Effect conc.:
1 152 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mobility
Duration:
24 h
Dose descriptor:
LOELR
Effect conc.:
> 3 000 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mobility
Duration:
48 h
Dose descriptor:
LOELR
Effect conc.:
3 000 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mobility
Duration:
24 h
Dose descriptor:
NOELR
Effect conc.:
>= 2 000 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mobility
Duration:
48 h
Dose descriptor:
NOELR
Effect conc.:
2 000 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mobility
Details on results:
After pH adjustment, the measured Ta5+ concentrations were low and showed high variability. Therefore, no concentration-response relationship could be established. Concentrations of the test sample varied due to precipitation, agglomeration and adsorption reactions. In addition, slight changes in pH had profound impact on the test concentrations. Observed immobilization effects may therefore rather predominantly refer to elevated NaCl, concentrations originated from neutralization, than released Ta5+ ions. Hypothetical Ta5+ related effects cannot be distinguished from NaCl induced inhibition in the conducted test. Therefore, only nominal effect levels were calculated.

- Mortality of control: 0
Results with reference substance (positive control):
- EC50 (24 h): 1.97 mg/L
- EC50 (48 h): < 1.25 mg/L

Table 3: Results of the Daphnia immobilization test after 24 and 48 h.

Nominal loading rate

[mg/L]

Volume test solution

[ml]

Time

[h]

Number immobile/ daphnids inserted

Sum immobile

Sum inserted

Immobilization

[%]

Oxygen

[mg/L]

pH

1

2

3

4

Initial

End

Initial

End

593

20

24

0/5

0/5

0/5

0/5

0

20

0

6.0

8.0

6.5

7.2

48

0/5

0/5

1/5

0/5

1

20

5

6.9

8.1

6.2

889

20

24

0/5

1/5

1/5

0/5

2

20

10

6.0

8.0

6.5

7.1

48

3/5

1/5

1/5

2/5

7

20

35

6.9

8.3

6.1

1333

20

24

0/5

0/5

0/5

0/5

0

20

0

6.4

8.1

6.5

7.2

48

0/5

0/5

0/5

0/5

0

20

0

6.9

8.2

6.2

2000

20

24

0/5

0/5

0/5

0/5

0

20

0

5.9

8.0

6.5

7.2

48

0/5

1/5

2/5

3/5

6

20

30

6.8

8.3

6.2

3000

20

24

1/5

1/5

1/5

1/5

4

20

20

6.2

8.1

6.5

7.1

48

2/5

3/5

4/5

3/5

12

20

60

6.8

8.3

6.1

Control

24

0/5

0/5

0/5

0/5

0

20

0

7.2

7.4

6.9

7.4

48

0/5

0/5

0/5

0/5

0

20

0

7.4

7.9

7.3

7.3

Table 4: Results of the chemical analysis of the control and the test loading rates 593, 1333 and 3000 mg/L.

Sample

NC

A

C

E

Nominal loading rate [mg/L]

0

593

1333

3000

Measured concentration [µg/L]

Before chemical digestion

0 h

< LOQ

< LOQ

1.44

8.36

24 h (aged)

< LOQ

< LOQ

< LOQ

1.67

24 h (fresh)

< LOQ

0.65

< LOQ

1.12

48 h

-

< LOQ

0.42

1.05

After chemical digestion

0 h

< LOQ

1.0

144

58.9

24 h (aged)

< LOQ

< LOQ

76.5

19.1

24 h (fresh)

< LOQ

5.82

2.91

4.09

48 h

< LOQ

2.53

15.4

6.93

LOQ (Limit of quantification) = 0.5 μg/L

Validity criteria fulfilled:
yes
Conclusions:
For the conducted semi-static acute immobilization test with Daphnia magna, applying nominal concentrations of 593 to 3000 mg/L tantalum pentachloride, nominal effect levels were calculated: 24h EL10 (nominal): 2380 mg/L (95%-CI: n.d.); 24h LOELR: > 3000 mg/L; 24h NOELR: ≥ 2000 mg/L; 48 h EL50 (nominal): 3086 mg/L (95%-CI: n.d.); 48h EL20 (nominal): 1152 mg/L (95%-CI: n.d.); 48h EL10 (nominal): 688 mg/L (95%-CI: n.d.); 48h LOELR: 3000 mg/L; 48h NOELR: 2000 mg/L. Due to methodological difficulties, it was not possible to calculate effect concentrations based on measured concentrations. Hence, values are reported based on the nominal loading rates.
Executive summary:

The 48 h acute toxicity of tantalum pentachloride to Daphnia magna Straus was studied under semi-static conditions. Daphnids were exposed to a control containing no test substance and tantalum pentachloride at nominal loading rates of 593, 889, 1333, 2000 and 3000 mg/L for 48 h. Immobilization was observed daily. Due to highly variable Ta5+ concentrations in solution, effect concentrations were based on nominal loading rates. The 48-hour EL50 was 3086 mg/L. The 48-h NOELR based on immobilization was 2000 mg/L and the LOELR was 3000 mg/L.

This study is classified as acceptable and satisfies the guideline requirements for an acute toxicity study with freshwater invertebrates.

However, it was not possible to determine effect levels based on measured effective test substance concentrations. After pH adjustment the measured Ta5+ concentrations were low and showed high variability. Measured values of Ta5+ ranged from < LOQ to 8.36 µg/L before chemical digestion of samples and from < LOQ to 144 µg/L after chemical digestion of samples. Therefore, no concentration-response relationship could be established. Concentrations of the test sample varied due to precipitation, agglomeration and adsorption reactions. In addition, slight changes in pH had profound impact on the test concentrations. Observed immobilization effects may therefore rather predominantly refer to elevated NaCl concentrations, originated from neutralization, than released Ta5+ ions. Reported EC50 values for sodium chloride vary but may be as low as 874 mg/L (ECHA registry for sodium chloride). Due to a concentration of approximately 2.34 g/L NaCl, present at the highest loading rate of 3000 mg/L test substance, and the sensitivity of D.magna to salinity, any hypothetical Ta5+ related effects cannot be distinguished from NaCl induced inhibition in the conducted test.

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

The 48 h acute toxicity to aquatic invertebrates (Daphnia magna) was investigated in a study according to GLP and OECD 202 under semi-static conditions. It was not possible to determine effect levels based on effective measured concentrations of tantalum pentachloride due to high variability depending on slightly changing pH. Therefore, only nominal effect loading rates are given. The 48-hour EL50 was 3086 mg/L.

It was not possible to determine effect levels based on measured effective test substance concentrations. After pH adjustment the measured Ta5+ concentrations were low and showed high variability. Measured values of Ta5+ ranged from < LOQ to 8.36 µg/L before chemical digestion of samples and from < LOQ to 144 µg/L after chemical digestion of samples. Concentrations of the test sample varied due to precipitation, agglomeration and adsorption reactions. In addition, slight changes in pH had profound impact on the test concentrations. Observed immobilization effects may therefore rather predominantly refer to elevated NaCl concentrations, originated from neutralization, than released Ta5+ ions. Due to a concentration of approximately 2.34 g/L NaCl, present at the highest loading rate of 3000 mg/L test substance, and the sensitivity of D.magna to salinity, any hypothetical Ta5+ related effects cannot be distinguished from NaCl induced inhibition in the conducted test.

Key value for chemical safety assessment

Additional information

According to Annex VII and VIII section 9.1.1 column 2 of the Regulation (EC) No 1907/2006 tests on short-term toxicity to aquatic invertebrates 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 the substance is expected to be highly insoluble (21 .3 µg/L) , see section 4.8 (Fox, 2012), the substance is not expected to be toxic to aquatic invertebrates. Nevertheless, toxicity data from read-across sources are used to describe the toxicity.

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.