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Short-term toxicity to fish

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Endpoint:
short-term toxicity to fish
Type of information:
read-across based on grouping of substances (category approach)
Adequacy of study:
key study
Study period:
2008-09-25 to: 2009-03-13
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
guideline study with acceptable restrictions
Remarks:
Well documented, scientifically sound study conducted in accordance to GLP and OECD guideline 203 with no deviation to the protocol. The reliability of this study for the substance tested is a K1, but in application of read-across to a different substance ECHA’s guidance specifies that the score can be a maximum of K2. Due to lower transformation/dissolution results for tungsten metal (the target substance) than sodium tungstate (the source substance), the resulting toxicity potential would also be expected to be lower, so read-across is appropriate. In addition, read-across is justified because the classification and labelling is the less severe for the target substance and the PBT/vPvB profile is the same. Finally, the dose descriptor for the target substance is expected to be sufficiently lower than the source chemical, and read-across to the source chemical is adequately protective. For more details refer to the attached description of the read across approach.
Justification for type of information:
REPORTING FORMAT FOR THE CATEGORY APPROACH
1. HYPOTHESIS FOR THE CATEGORY APPROACH: The hypothesis is that properties are likely to be similar or follow a similar pattern because of the presence of a common metal ion, in this case tungstate.
2. SOURCE AND TARGET CHEMICAL(S) (INCLUDING INFORMATION ON PURITY AND IMPURITIES):
Source: Sodium Tungstate
Target: Tungstic acid
3. CATEGORY APPROACH JUSTIFICATION: See Annex 3 in CSR
4. DATA MATRIX: See Annex 3 in CSR
Reason / purpose for cross-reference:
read-across: supporting information
Qualifier:
according to guideline
Guideline:
OECD Guideline 203 (Fish, Acute Toxicity Test)
Deviations:
no
GLP compliance:
yes
Specific details on test material used for the study:
Details on properties of test surrogate or analogue material (migrated information):
no data
Analytical monitoring:
yes
Details on sampling:
- Concentrations: 0 (control), 13, 25, 50, 100, and 200 mg/L; A volume of 10 mL was collected from each control and test substance replicate at 0 and 96 hours and transferred to a culture tube.
- Sampling method: 0.05 mL aliquot of each sample was taken, diluted if necessary with 2% HNO3, capped and shaken to mix.
- Sample storage conditions before analysis: Room temperature
Vehicle:
no
Details on test solutions:
PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: 7.5075 g of sodium tungstate dihydrate was added to a 21-L glass jar and bringing the jar to a volume of 15,000 mL with blended freshwater. Appropriate aliquots of the primary standard were diluted with 15 L of dilution water to prepare final test concentrations of 13, 25, 50, 100, and 200 mg total product/L. The control solution consisted only of dilution water.
Test organisms (species):
Danio rerio (previous name: Brachydanio rerio)
Details on test organisms:
TEST ORGANISM
- Common name: Zebrafish
- Source: Osage Catfisheries, Osage Beach, Missouri
- Age at study initiation (mean and range, SD): Not specified
- Length at study termination (length definition, mean, range and SD): 28-31 mm; mean 30 ± 1.2 mm (Controls only)
- Weight at study termination (mean and range, SD): 0.194-0.408 g; mean 0.276 ± 0.0664 g (Controls only)
- Feeding during test
- Frequency: Not fed during test, or one day prior

ACCLIMATION
- Acclimation period: 5 days
- Acclimation conditions (same as test or not): Temperature adjusted for test
- Type and amount of food: Salmon starter, flake food, and brine shrimp
- Feeding frequency: Daily
- Health during acclimation (any mortality observed): No mortality observed in 14 days prior to testing.



Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
96 h
Post exposure observation period:
None
Hardness:
140 mg/L CaCO3
Test temperature:
23 ± 1 ⁰C
pH:
8.0-8.3 SU
Dissolved oxygen:
6.7-8.3 mg/L (82 to 101% sat)
Salinity:
Not applicable
Nominal and measured concentrations:
Nominal- 0 (control), 13, 25, 50, 100, and 200 mg/L.
Mean calculated-
Details on test conditions:
TEST SYSTEM
- Test vessel:
- Type (delete if not applicable): closed
- Material, size, headspace, fill volume: 21 L glass jars, covered with plastic Petri dishes; 15 L test solution.
- Aeration: None
- No. of organisms per vessel: 10
- No. of vessels per concentration (replicates): 1
- No. of vessels per control (replicates): 1
- Biomass loading rate: 0.18 g fish tissue/L test solution

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Moderately hard freshwater made with naturally hard well water blended with well water demineralized by reverse osmosis, total hardness of 130-160 mg/L CaCO, passed through a sediment filter prior to use.
- Metals: B-0.415 mg/L, Ca-83.1 mg/L, Mg- 33.1 mg/L, K-7.93 mg/L, Na-32.2 mg/L; all others below DL.
- Pesticides: Below DL
- Alkalinity: 150 mg/L CaCO3
- Conductivity: 328 uS
- Intervals of water quality measurement: Daily

OTHER TEST CONDITIONS
- Adjustment of pH: None
- Photoperiod: 16h light/ 8h dark, with 30 min simulated dawn and dusk periods
- Light intensity: 542 lux at initiation of the definitive test as measured with a LI COR Model LI-189 light meter equipped with a photometric sensor.

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : Mortality, 24h

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 2x
- Range finding study: Other studies indicated a low potential for toxicity to aquatic organisms; Therefore, a range finding study was not performed. Definitive testing was performed at a level that exceeds the guideline-required maximum, 100 mg/L for this test.
Reference substance (positive control):
no
Duration:
96 h
Dose descriptor:
LC50
Effect conc.:
> 200 mg/L
Nominal / measured:
nominal
Conc. based on:
other: sodium tungstate concentration
Basis for effect:
mortality (fish)
Remarks on result:
other: No mortality in any control or test solution
Duration:
96 h
Dose descriptor:
LC50
Effect conc.:
> 181 mg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
other: sodium tungstate concentration
Basis for effect:
mortality (fish)
Remarks on result:
other: No mortality in any control or test solution
Duration:
96 h
Dose descriptor:
NOEC
Effect conc.:
200 mg/L
Nominal / measured:
nominal
Conc. based on:
other: sodium tungstate concentration
Basis for effect:
behaviour
Remarks on result:
other: Lack of mortality and sublethal effects
Duration:
96 h
Dose descriptor:
NOEC
Effect conc.:
>= 181 mg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
other: sodium tungstate concentration
Basis for effect:
behaviour
Remarks on result:
other: Lack of mortality and sublethal effects
Details on results:
Biological Results:
After 96 hours of exposure, there was no mortality in the 0 (control) or any of the test substance treatments. There were no sublethal observations during the exposure. The estimated 24-, 48-, 72-, and 96-hour LC50 values for zebrafish exposed to sodium tungstate dihydrate were >200 mg/L, the highest concentration tested. Since there was no partial response, the 96-hour slope of the concentrations-response line could not be calculated from the probit analysis. The 96 hour no-observed-effect concentration (NOEC) was 200 mg/L based on the lack of mortality and sublethal effects atthis and lower test substance concentrations.
Reported statistics and error estimates:
Estimates of LC50 values and their 95% confidence limits were calculated using the probit method and Trimmed Spearman-Karber method. When the p value for Goodness of Fit was >0.05 and there was no other evidence of questionable convergence, the probit method was selected for reporting. When this criterion was not achieved, the Trimmed Spearman-Karber method was selected for reporting. The no observed-effect concentration (NOEC) was determined based on the absence of any mortality or sublethal effects.
Conclusions:
Based on nominal concentrations, the estimated 96 hour LC50 value for zebrafish exposed to sodium tungstate dihydrate was >200 mg/L, the highest concentration tested. The 96 hour slope of the concentrations-response line could not be calculated. The 96-hour no-observed-effect concentration (NOEC) was 200 mg/L, based on the lack of mortality and sublethal effects at this and the lower concentrations.
Executive summary:

No acute fish toxicity data of sufficient quality are available for tungstic acid (target substance). However, acute fish toxicity data are available for sodium tungstate (source substance), which will be used for read-across. Due to lower water solubility and lower toxicity for the target substance compared to the source substance, the resulting read-across from the source substance to the target substance is appropriate as a conservative estimate of potential toxicity for this endpoint. In addition, read-across is appropriate because the classification and labelling is more protective for the source substance than the target substance, the PBT/vPvB profile is the same, and the dose descriptors are, or are expected to be, lower for the source substance. For more details, refer to the attached description of the read-across approach.

Endpoint:
short-term toxicity to fish
Type of information:
read-across based on grouping of substances (category approach)
Adequacy of study:
key study
Study period:
4 November 2002 - 8 November 2002
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Remarks:
Well documented, scientifically sound study that was conducted in accordance with GLP and generally accepted guidelines
Justification for type of information:
Tungstic acid (WO3•H2O) is the hydrated form of tungsten trioxide (WO3). Based on Annex V, hydrates and water free forms (anhydrous) of compounds can be regarded as the same substance for registration purposes. Therefore, tungstic acid will be considered equivalent to WO3. For more details on the rationale, refer to the attached description of the read-across approach.
Qualifier:
according to guideline
Guideline:
EU Method C.1 (Acute Toxicity for Fish)
Qualifier:
equivalent or similar to guideline
Guideline:
OECD Guideline 203 (Fish, Acute Toxicity Test)
GLP compliance:
yes
Analytical monitoring:
yes
Details on sampling:
no data
Vehicle:
no
Details on test solutions:
no data
Test organisms (species):
Danio rerio (previous name: Brachydanio rerio)
Details on test organisms:
TEST ORGANISM
- Common name: Zebra fish
- Source: Di Mamma (Netherlands)
- Length at study initiation (length definition, mean, range and SD): mean 3.5 cm (S.D. = 0.33 cm)

ACCLIMATION
- Acclimation period: Stock held since September 2, 2002 and acclimatised to the test conditions since then.
- Acclimation conditions (same as test or not): same
- Type and amount of food: Commerical fish food
- Feeding frequency: daily; discontinued 24 hours prior to the test
- Health during acclimation (any mortality observed): < 5% mortalities
Test type:
static
Water media type:
freshwater
Limit test:
yes
Total exposure duration:
96 h
Post exposure observation period:
no data
Hardness:
173.1 mg/L CaC03
Test temperature:
20.8-22.0 ⁰C (in the temperature range of 20-24 ⁰C)
pH:
7.5-7.7
Dissolved oxygen:
8.2-8.4 mg/L (92-97% saturation)
Salinity:
n/a
Nominal and measured concentrations:
Nominal: 2.5 mg/L (WO3)
Measured: 5.2 - 5.3 mg/L (WO3)
Measured: 4.15 - 4.20 mg/L (W)
Details on test conditions:
TEST SYSTEM
- Test vessels: Glass aquaria holding 5 L of test media
- Aeration: gentle aeration via narrow glass tubes
- Experimental design: 1 test concentration (2.5mg/L) plus 1 control, no feeding during the exposure period, static system
- Renewal rate of test solution (frequency/flow rate): None
- No. of organisms per vessel: 10 animals per test concentration
- Photoperiod: 16 hours light, 8 hours dark
- Biomass loading rate: 0.88 g body weight (wet weight) per litre

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Reconstituted water prepared according to the recommendations of ISO 7346. This freshly prepared standard dilution water is used for both the maintenance of the test animals under flow-through conditions and the preparation of stock and test solutions of the test substance.
Reference substance (positive control):
no
Duration:
48 h
Dose descriptor:
LC0
Effect conc.:
>= 5.25 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
test mat.
Remarks:
WO3
Basis for effect:
mortality (fish)
Duration:
48 h
Dose descriptor:
LC0
Effect conc.:
>= 4.16 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
act. ingr.
Remarks:
Tungsten (W)
Basis for effect:
mortality (fish)
Duration:
72 h
Dose descriptor:
LC0
Effect conc.:
>= 5.26 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
test mat.
Remarks:
WO3
Basis for effect:
mortality (fish)
Duration:
72 h
Dose descriptor:
LC0
Effect conc.:
>= 4.18 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
act. ingr.
Remarks:
Tungsten (W)
Basis for effect:
mortality (fish)
Duration:
96 h
Dose descriptor:
LC0
Effect conc.:
>= 5.25 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
test mat.
Remarks:
WO3
Basis for effect:
mortality (fish)
Duration:
96 h
Dose descriptor:
LC0
Effect conc.:
>= 4.16 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
act. ingr.
Remarks:
Tungsten (W)
Basis for effect:
mortality (fish)
Details on results:
All results are expressed in terms of mean measured concentrations. Measured concentrations correspond to 212% of nominal values of tungsten trioxide at 0 hours, to 208% of nominal values of tungsten trioxide at 24 hours, to 212% of nominal values of tungsten trioxide at 48 hours to 212% of tungsten trioxide at 72 hours, and 208% of nominal values of tungsten trioxide at 96 hours, respectively.
Results with reference substance (positive control):
n/a
Reported statistics and error estimates:
no data
Conclusions:
Highest test concentration resulting in 0% mortality (LC 0 96h): >= 5.25 mg/L test substance.
Executive summary:

No acute fish toxicity data are available for tungstic acid (target substance). However, acute fish toxicity data are available for tungsten trioxide (source substance), which were used for read-across. Tungstic acid (WO3•H2O) is the hydrated form of tungsten trioxide (WO3). Based on Annex V, hydrates and water free forms (anhydrous) of compounds can be regarded as the same substance for registration purposes. Therefore, tungstic acid will be considered equivalent to WO3. For more details on the rationale, refer to the attached description of the read-across approach.

Description of key information

No data for acute toxicity to fish are available for tungstic acid; therefore, data for WO3 and sodium tungstate were evaluated for this endpoint. In a static 96-h assay with Danio rerio (zebrafish) testing of WO3, the 96-h LC0 was found to be greater than the highest concentration tested (>5.25 mg WO3/L or approximately 4.16 mg W/L) based on mean measured concentrations. No mortality occurred in this test and, therefore, a definitive effect concentration does not exist for this assay; therefore, data from sodium tungstate were used for read-across. In a 96-h assay testing sodium tungstate with zebrafish, the 96-h LC50 was determined to be >181 mg sodium tungstate/L (ca. >106 mg W/L) based on mean measured concentrations.

Key value for chemical safety assessment

Fresh water fish

Fresh water fish
Effect concentration:
106 mg/L

Additional information

No acute toxicity data for aquatic invertebrates are available for tungstic acid (target substance). However, acute aquatic invertebrate toxicity data are available for WO3 and sodium tungstate (source substances), which were evaluated for read-across. Tungstic acid (WO3•H2O) is the hydrated form of tungsten trioxide (WO3). Based on Annex V, hydrates and water free (anhydrous) forms of compounds can be regarded as the same substance for registration purposes. Therefore, tungstic acid will be considered equivalent to WO3. For more details on the rationale for read-across to WO3and sodium tungstate, refer to the read-across category approach document (Annex 3).