Niobium dioxide

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2003-02-19 to 2003-02-21

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Version / remarks:

December 1992

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: test item was provided by the sponsor, Batch number: SNB10OG200277M
- Expiration date of the lot/batch: 2003-12-31
- Purity test date: >99 %

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: Protected from moisture
- Stability under test conditions: not specified
- Solubility and stability of the test substance in the solvent/vehicle: Hardly soluble in water, <10 mg/L (OECD 105)

TREATMENT OF TEST MATERIAL PRIOR TO TESTING
- Treatment of test material prior to testing: Stock solution: 100 mg/L, prepared with dilution water. The stock solution was shaken for 24 h at 50-60 rpm (step 3 to 4) at rotating shaker RELAX2 in 1x1L brown glass bottles. Undissolved particles of the test item were removed by filtration (pore size 0.45 μm).
- Final dilution of a dissolved solid, stock liquid or gel: 100 mg/L, prepared with dilution water

OTHER SPECIFICS: Black powder, CAS RN: 12034-57-0

Analytical monitoring:

yes

Details on sampling:

Concentration control analysis was carried out and reported by the sponsor. 2 x 100 ml each of the saturated concentration and control were sampled at the beginning and end of the test. The samples were stored in PE bottles at 4 - 8 °C until shipping.

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: The stock solution was shaken for 24 h at 50 - 60 rpm (step 3 to 4) at rotating shaker RELAX2 in 1 x 1 L brown glass bottles. Undissolved particles of the test item were removed by filtration (pore size 0.45 μm). The test item was clearly dissolved throughout exposure in the tested saturation concentration. Saturation concentration: The maximum dissolved concentration of the test item that can be achieved under the test conditions in the test medium, acc. to OECD Series, No. 23.
- Controls: Dilution water without test item tested under the same conditions as the test group.
- Evidence of undissolved material (e.g. precipitate, surface film, etc.): Undissolved particles of the test item were removed by filtration (pore size 0.45 μm).

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: Daphnia magna Straus
- Source: lnstitut für Wasser-, Boden- und Lufthygiene (WaBoLu). Daphnids were obtained by removing the mother animals twice within 22 h.
- Age at study initiation: 2 - 24 h
- Feeding during test: no
- Feeding during in-house breeding:
* Food type: ad libitum with a mix of Desmodesmus subspicatus and Chlorella vulgaris
* Amount: algae cell density of > 10^6 cells/mL
* Frequency: at least 5x weekly

ACCLIMATION
- Acclimation period: Ca. 2 h in dilution water
- Acclimation conditions (same as test or not): same as test
- Type and amount of food: no feeding
- Feeding frequency: no feeding
- Health during acclimation (any mortality observed): no

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

48 h

Hardness:

256 mg/L (see also Table 3 in "Any other information on materials and methods incl. tables")

Test temperature:

During the test the temperature was in the range of 20 ± 1 °C

pH:

7.60 - 7.82 in the control and 7.45 - 7.6 in the test item treatments (see also Table 1 in "Any other information on materials and methods incl. tables")

Dissolved oxygen:

8.10 - 9.11 mg/L in the control and 8.50 - 8.85 mg/L in the test item treatment (see also Table 1, 2 and 3 in "Any other information on materials and methods incl. tables")

Salinity:

not applicable

Conductivity:

Conductivity of the dilution water prior test start: 657 μS/cm (see also Table 3 in "Any other information on materials and methods incl. tables")

Nominal and measured concentrations:

Saturated solution: The maximum dissolved concentration of the test item that can be achieved under the test conditions in the test medium acc. to OECD Series, No. 23.; see also Table 4 for in "Any other information on materials and methods incl. tables" ; the content of dissolved niobium is always below 1 mg/L.

Details on test conditions:

TEST SYSTEM
- Test vessel: Glass beakers (5 cm ID x 8 cm H), 50 ml volume
- Fill volume: 20 mL
- Aeration: no
- Renewal rate of test solution (frequency/flow rate): not applicable, static test
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 4
- No. of vessels per vehicle control (replicates): not applicable
- No. of organisms per vessel, reference item: 10
- No. of vessels per concentration, reference item (replicates): 2

OTHER TEST CONDITIONS
- Adjustment of pH: 7.45 - 7.63
- Photoperiod: 16/8 h light/dark cycle
- Light intensity: Diffuse light, illumination range max. 20 µmol/ (m² .s) (corresponding to 1200 Ix)

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

VEHICLE CONTROL PERFORMED: yes

RANGE-FINDING STUDY
- Test concentrations: 4 dilutions of the saturated solution of the test item ranging from 1:1 to 1:1000 set up in a geometric series with a factor of 10 (NON-GLP).
- Results used to determine the conditions for the definitive study: 100 mg/L were weighed out and treated as described above (see "DETAILS ON PRETREATMENT")

Reference substance (positive control):

yes

Remarks:

Potassium dichromate

Key result

Duration:

48 h

Dose descriptor:

LC0

Effect conc.:

100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: no effect was observed in the saturated solution (LOD = 1 mg/L)

Details on results:

The percentage immobilisation was determined in the tested saturation concentration and the control after 24 hand 48 h. There was no biologically significant effect in the test solution at saturation concentration. No immobilisation in the control group was observed.

Results with reference substance (positive control):

EC-values after 24 h of the reference item potassium dichromate in mg/L were as follows:
EC10: 0.83
EC50: 2.17 (Cl 1.66- 2.83)
EC100: 5.80
The EC50-value of reference item potassium dichromate after 24 h is within the prescribed concentration range of 1.0 - 2.5 mg/L of validity criteria according to AQS: DIN Guideline 38412 L 30.

Table 1: Water Parameters at the Beginning of the Test (0 h)

Test group	pH-Value	O2-Concentration [mg/L]
Saturation concentration	7.45	8.85
Control	7.82	9.11

Table 2: Water Parameters at the End of Test (48 h)

Test group	pH-Values Replicates				O2-Concentration [mg/L] Replicates
	1	2	3	4	1	2	3	4
Saturation concentration	7.60	7.59	7.58	7.50	8.53	8.56	8.52	8.50
Control	7.61	7.63	7.63	7.60	8.10	8.07	8.17	8.11

Table 3: Water Parameters of the Dilution Water

Dilution Water	pH-Value	O2-Conc. [mg/L]	Temp. [°C]	Conduct [µS/cm]	Total Hardness CaCO3 [mg/L]
2003-02-19	7.82	9.11	19.3	657	256

Table 4: Content of Niobium

Test group	Niobium [mg/L]
	0 h	48 h
Saturation concentration	< 1	< 1
Control	< 1	< 1

Validity criteria fulfilled:

yes

Conclusions:

No immobilisation of Daphnia magna was observed after exposure to the test item at saturation concentration for up to 48 hours.

Executive summary:

The 48–h-acute immobilisation test of niobium oxide to Daphnia magna was conducted under static conditions. Daphnids were exposed to the test chemical in saturated solution (loading level 100 mg/L) for 48 h. The analytically determined actual Nb concentration was below 1 mg/L. No immobilization was observed after 24 and 48 hours of exposure to the test item. No immobilisation in the control group was observed.

In accordance with the CLP classification criteria for aquatic toxicty, the substance does not need to be classified based on the results of this study.

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

Results Synopsis

Test Organism Age: 2 - 24 h old

Test Type: Static, limit test with saturated solution

EC₅₀: no effect was observed in the saturated solution; (measured concentration a.i. < 1mg/L)

Endpoint(s) Effected: mobility

Reference 2

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:

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

Key result

Duration:

48 h

Dose descriptor:

LC0

Effect conc.:

100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: no effect was observed in the saturated solution (LOD = 1 mg/L)

Details on results:

The percentage immobilisation was determined in the tested saturation concentration and the control after 24 hand 48 h. There was no biologically significant effect in the test soluation at saturation concentration. No immobilisation in the control group was observed.

Results with reference substance (positive control):

EC-values after 24 h of the reference item potassium dichromate in mg/L were as follows:
EC10: 0.83
EC50: 2.17 (Cl 1.66- 2.83)
EC100: 5.80
The EC50-value of reference item potassium dichromate after 24 h is within the prescribed concentration range of 1.0 - 2.5 mg/L of validity criteria according to AQS: DIN Guideline 38412 L 30.

Table 1: Water Parameters at the Beginning of the Test (0 h)

Test group	pH-Value	O2-Concentration [mg/L]
Saturation concentration	7.45	8.85
Control	7.82	9.11

Table 2: Water Parameters at the End of Test (48 h)

Test group	pH-Values Replicates				O2-Concentration [mg/L] Replicates
	1	2	3	4	1	2	3	4
Saturation concentration	7.60	7.59	7.58	7.50	8.53	8.56	8.52	8.50
Control	7.61	7.63	7.63	7.60	8.10	8.07	8.17	8.11

Table 3: Water Parameters of the Dilution Water

Dilution Water	pH-Value	O2-Conc. [mg/L]	Temp. [°C]	Conduct [µS/cm]	Total Hardness CaCO3 [mg/L]
2003-02-19	7.82	9.11	19.3	657	256

Table 4: Content of Niobium

Test group	Niobium [mg/L]
	0 h	48 h
Saturation concentration	< 1	< 1
Control	< 1	< 1

Validity criteria fulfilled:

yes

Conclusions:

No immobilisation of Daphnia magna was observed after exposure to the test item at saturation concentration for up to 48 hours.

Executive summary:

The 48–h-acute immobilisation test of niobium oxide to Daphnia magna was conducted under static conditions. Daphnids were exposed to the test chemical in saturated solution (loading level 100 mg/L) for 48 h. The analytically determined Nb concentration was below 1 mg/L. No immobilization was observed after 24 and 48 hours of exposure to the test item. No immobilisation in the control group was observed.

In accordance with the CLP classification criteria for aquatic toxicty, the substance does not need to be classified based on the results of this study.

 

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

Results Synopsis

Test Organism Age: 2 - 24 h old

Test Type: Static, limit test with saturated solution

EC₅₀: no effect was observed in the saturated solution; (measured concentration a.i. < 1mg/L)

Endpoint(s) Effected: mobility

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

No adverse effects could be demonstrated on Daphnia magna after exposure to a saturated NbO solution for up to 48 h. The test was conducted according to EC Directive 92/69/EC method C.2. The saturated solution was prepared at a nominal loading level of 100 mg/L and used in the test after shaking for 24 h and subsequent filtration. The actual concentration of Nb in the test solution was verified to be below 1 mg/L.

Additional information

The key 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.