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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:
2008-10-14 to: 2009-03-13
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Remarks:
Well documented, scientifically sound study that was conducted in accordance to GLP and OECD guideline 202 with no deviation to the protocol.
Qualifier:
according to guideline
Guideline:
OECD Guideline 202 (Daphnia sp. Acute Immobilisation 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: 10 mL from each control and treatment at 0 and 48 h 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 and analyzed by ICP MS.
- 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: 0.4004 g sodium tungstate dihydrate was dissolved in 2 L aged-blended freshwater. Test concentrations were diluted from this solution.
- Controls: Aged-blended freshwater only.
- Evidence of undissolved material (e.g. precipitate, surface film, etc): None
Test organisms (species):
Daphnia magna
Details on test organisms:
TEST ORGANISM
- Common name: Water flea
- Source: In-house daphnid culture
- Age at study initiation (mean and range, SD): <24h
- Feeding during test
- Frequency: Not fed during test


ACCLIMATION
- Acclimation period: None necessary, as culture conditions are the same as test conditions
- Type and amount of food: Suspension of Pseudokirchneriella subcapitata, supplemented by artificial diet.
- Feeding frequency: Daily
- Health during acclimation (any mortality observed): No mortality in adults at least 48 h prior to testing


Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
48 h
Post exposure observation period:
None
Hardness:
144 mg/L CaCO3
Test temperature:
19.3-19.5 degrees C
pH:
8.3-8.5 SU
Dissolved oxygen:
7.6-7.9 mg/L (85 to 89% saturation)
Salinity:
n/a
Nominal and measured concentrations:
Nominal- 0, 13, 25, 50, 100 and 200 mg/L
Mean Calculated- < MQL, 11.9, 21.5, 41.5, 90.8, and 163 mg/L
Details on test conditions:
TEST SYSTEM
- Test vessel:
- Type: closed
- Material, size, headspace, fill volume: Glass 250 mL jars, containing 200 mL test solution, covered with a plastic Petri dish
- Aeration: No
- 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: ABC well water mixed with well water demineralized by reverse osmosis, then aged in a tank containing aquaticorganisms. Water was then passed through a sediment filter, a UV sterilizer, and aerated 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: 142 mg/L CaCO3
- Conductivity:347 uS
- Culture medium different from test medium: No
- Intervals of water quality measurement: Daily

OTHER TEST CONDITIONS
- Adjustment of pH: No
- Photoperiod: 16 hr light, 8hr dark
- Light intensity: 448 lux as measured with a LI-COR Model LI-189 light meter equipped with a photometric sensor.
- The jars were maintained at 20 ± 2 degrees C in a temperature-controlled water bath.

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : Immobility and mortality, 24 hr.

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 2x
- Range finding study
- Test concentrations: 0, 0.10, 1.0, 10, and 100 mg/L
- Results used to determine the conditions for the definitive study: Yes
Reference substance (positive control):
no
Duration:
24 h
Dose descriptor:
EC50
Effect conc.:
> 163 mg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
test mat.
Remarks:
based on mean calculated concentrations of sodium tungstate
Basis for effect:
other: immobilization
Duration:
48 h
Dose descriptor:
EC50
Effect conc.:
> 163 mg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
test mat.
Remarks:
based on mean calculated concentrations of sodium tungstate
Basis for effect:
other: immobilization
Duration:
48 h
Dose descriptor:
NOEC
Effect conc.:
90.8 mg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
test mat.
Remarks:
based on mean calculated concentrations of sodium tungstate
Basis for effect:
other: immobilization
Details on results:
Biological Results:
After 48 hours of exposure, immobility was 0, 0, 0, 0, 5 and 15% in the 163 mg /L, the highest level tested. Immobility was significantly increased at only the highest test concentration level. The 48-hour no-observed-effect concentration (NOEC) was determined to be 90.8 mg/L, based on the lack of statistically significant (p=0.05) immobility and sublethal effects at this test substance treatment.
Reported statistics and error estimates:
All statistical analyses were performed with SAS software. 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 by using a one-tailed Dunnett’s test.
Conclusions:
The 48 hour EC50 value was estimated to be >163 mg/L. The 48-hour no-observed-effect concentration (NOEC) was 90.8 mg/L based on the lack of statistically significant (p=0.05) immobility and sublethal effects at this and lower test substance treatments.

Endpoint:
short-term toxicity to aquatic invertebrates
Type of information:
experimental study
Adequacy of study:
supporting study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
guideline study with acceptable restrictions
Remarks:
Guideline study with limited documentation on the preparation of test solutions and test conditions provided and analytical confirmation of test solutions not performed.
Reason / purpose for cross-reference:
reference to same study
Qualifier:
according to guideline
Guideline:
OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)
Deviations:
yes
Remarks:
: analytical confirmation of test solutions was not performed
GLP compliance:
not specified
Analytical monitoring:
no
Vehicle:
no
Details on test solutions:
N/A
Test organisms (species):
Daphnia magna
Details on test organisms:
TEST ORGANISM
- Common name: Water flea
- Strain: N/A
- Source: Daphtoxkit, MicroBio Tests, Inc
- Age at study initiation (mean and range, SD): < 24 h
- Method of breeding: purchased eggs
- Feeding during test
- Food type: powdered Spirulina algae
- Amount: ad libitum
- Frequency: fed 2 hours prior to test initiation, not fed during test.
Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
48 h
Post exposure observation period:
None
Hardness:
No data
Test temperature:
No data
pH:
No data
Dissolved oxygen:
No data
Salinity:
No data
Nominal and measured concentrations:
Nominal- Control, 0.09, 0.288, 0.9, 2.88, and 9 g/L
Details on test conditions:
TEST SYSTEM
- Test vessel:
- Type (delete if not applicable): open
- Material, size, headspace, fill volume: Plastic plates with 24-10 mL test wells.
- Aeration: no
- Type of flow-through (e.g. peristaltic or proportional diluter): N/A
- Renewal rate of test solution (frequency/flow rate): N/A
- No. of organisms per vessel: 1 per test well, 5 per concentration per plate
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 5 control animals per plate
- No. of vessels per vehicle control (replicates): N/A
- Biomass loading rate: No data


TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Standard freshwater similar to OECD guideline.
- Total organic carbon: No data
- Particulate matter: No data
- Metals: No data
- Pesticides: No data
- Chlorine: No data
- Alkalinity: No data
- Ca/mg ratio: No data
- Conductivity: No data
- Culture medium different from test medium: No data
- Intervals of water quality measurement: No data


OTHER TEST CONDITIONS
- Adjustment of pH: No data
- Photoperiod: constant darkness
- Light intensity: N/A


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


TEST CONCENTRATIONS
- Spacing factor for test concentrations: approx. 3
- Justification for using less concentrations than requested by guideline: N/A
- Range finding study
- Test concentrations: No data
- Results used to determine the conditions for the definitive study: yes
Reference substance (positive control):
no
Duration:
24 h
Dose descriptor:
LC50
Effect conc.:
1.7 other: g W/L
Nominal / measured:
nominal
Conc. based on:
other: tungsten concentration
Basis for effect:
mobility
Duration:
48 h
Dose descriptor:
LC50
Effect conc.:
0.344 other: g W/L
Nominal / measured:
nominal
Conc. based on:
other: tungsten concentration
Basis for effect:
mobility
Remarks on result:
other: 95% CI = 0.244-0.485 g W/L
Details on results:
- Behavioural abnormalities: No data
- Observations on body length and weight: No data
- Other biological observations: See Table 1 for mortality data
- Mortality of control: none
- Other adverse effects control: none
- Abnormal responses: No data
- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: No data
- Effect concentrations exceeding solubility of substance in test medium: No data
Reported statistics and error estimates:
LC50 values in confidence intervals using the EPA Probit Analysis Program ver 1.5. Other statistical calculations were performed using Statistica 7.0 software.

Table 1. Results of D. magna test with sodium tungstate, alive/dead animals in each group.

 

Control

0.9 g/L

0.288 g/L

0.9 g/L

2.88 g/L

9.0 g/L

Exposure time

24

48

24

48

24

48

24

48

24

48

24

48

A

5/0

5/0

5/0

5/0

5/0

4/1

4/1

1/4

4/1

0/5

0/5

0/5

B

5/0

5/0

5/0

5/0

5/0

5/0

3/2

2/3

4/1

0/5

0/5

0/5

C

5/0

5/0

4/1

4/1

5/0

5/0

4/1

2/3

3/2

0/5

0/5

0/5

D

5/0

5/0

5/0

5/0

4/1

4/1

5/0

2/3

1/4

0/5

0/5

0/5

% Mortality

0

0

5

5

5

10

15

65

40

100

100

100

 

Validity criteria fulfilled:
not specified
Conclusions:
The 48 hour LC50 of sodium tungstate to D. magna is 0.344 g W/L, with a 95% confidence interval of 0.244-0.485 g W/L.
Endpoint:
short-term toxicity to aquatic invertebrates
Type of information:
experimental study
Adequacy of study:
supporting study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
comparable to guideline study with acceptable restrictions
Remarks:
Well documented, scientifically sound study conducated similar to OECD guideline 202 with minor protocol deviations regarding the test solutions, organisms and the range of temperature (lower than what the guideline specified).
Reason / purpose for cross-reference:
reference to other study
Qualifier:
equivalent or similar to guideline
Guideline:
OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)
GLP compliance:
not specified
Specific details on test material used for the study:
Details on properties of test surrogate or analogue material (migrated information):
no data
Analytical monitoring:
not specified
Details on sampling:
no data
Vehicle:
no
Details on test solutions:
- Stock solutions were made in distilled water.
- Sodium tungstate was dissolved by boiling in a small amount of dilute HCl.
Test organisms (species):
Daphnia magna
Details on test organisms:
TEST ORGANISM
- Common name: Water flea
- Strain: Straus
- Source: Wild caught from a natural pond at Gheru Campus of the Industrial Toxicology Research Center, Lucknow, India
- Age at study initiation (mean and range, SD): Not specified
- Feeding during test
- Frequency: Animals were not fed during the bioassay study.


ACCLIMATION
- Acclimation period: Not specified
- Acclimation conditions (same as test or not): Yes
- Type and amount of food: 100 mg/L suspension of dry fish food (Shalimar Fish Food Company, Bombay) and yeast
- Feeding frequency: Not specified
- Health during acclimation (any mortality observed): Not specified

QUARANTINE (wild caught)
- Duration: Not specified
- Health/mortality: Not specified

Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
48 h
Post exposure observation period:
None
Hardness:
235-260 mg/L as CaCO3
Test temperature:
11.5-14.5 C
pH:
7.2-7.8 SU
Dissolved oxygen:
5.2-6.5 mg/L
Salinity:
Not applicable
Nominal and measured concentrations:
Not specified
Details on test conditions:
TEST SYSTEM
- Test vessel:
- Type: open
- Material, size, headspace, fill volume: 200 mL beakers, 100 mL test water. The concentrations were given as milligrams per liter of metal ions.
- No. of organisms per vessel: 10 daphnids
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 3


TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: filtered aerated tubewell hard water (hardness- 240 mg/liter as CaCO3)
- Metals: 85-96 mg/L (Mg)
- Chlorine: 5-10 mg/L as chloride
- Alkalinity: 390-415 mg/L as CaCO3
- Culture medium different from test medium: No
- Intervals of water quality measurement: 24h


EFFECT PARAMETERS MEASURED (with observation intervals if applicable):
- Mortality (presumed dead when there was complete immobilization): 30 min, 1, 2, 4, 8, 14+2, 24, 33+3, and 48 hr.


TEST CONCENTRATIONS
- Spacing factor for test concentrations: Logarithmic scale (as outlined by APHA et al, 1977), not otherwise specified
- Range finding study
- Test concentrations: Stated as run, no further details
- Results used to determine the conditions for the definitive study: Yes
Reference substance (positive control):
no
Duration:
48 h
Dose descriptor:
EC50
Effect conc.:
89.39 mg/L
Nominal / measured:
meas. (not specified)
Conc. based on:
element
Remarks:
As Metal ion
Basis for effect:
mortality
Remarks on result:
other: 95 % CI is 78.04-99.51 mg/L
Duration:
24 h
Dose descriptor:
EC50
Effect conc.:
98.4 mg/L
Nominal / measured:
meas. (not specified)
Conc. based on:
element
Remarks:
As Metal ion
Basis for effect:
mortality
Remarks on result:
other: 95 % CI is 68.70-112.60 mg/L
Details on results:
- 48-hr EC50 molarity (M): 4.90 x 10^-4
- log M (pM): 3.31
Reported statistics and error estimates:
EC50 values and 95% confidence limits were calculated by the moving average-angle method of Harris, 1959. APHA et. al, 1977 was used to calculate pH, temperature, dissolved oxygen, hardness, and alkalinity. Negative logarithms of the EC50 values were compared to physicochemical properties of the metal.
Statisitical analysis was performed to find a general correlation, if any, between physiochemical properties and metal ion toxicity. The correlation coefficient (r) between physiochemical properties and EC50 values (pM) was determined by least square procedure (Snedecor and Cochran, 1967).
Conclusions:
The 48 h EC50 for tungsten metal ions to Daphnia magna is 89.39 mg/L, with 95% confidence limits of 78.04-99.51 mg/L.

Description of key information

The 48-hr EC50 for Daphnia magna found in a test conducted according to OECD 202, under GLP standards, and with analytical verification of the test concentrations was >163 mg sodium tungstate/L (>96 mg tungsten/L) . This finding was supported by two other tests conducted with similar methodology, which found 48-hr EC50s (reported as concentration of tungsten) of 89.4  and 344 mg tungsten/L. The 48-hr EC50 of >163 mg sodium tungstate is considered to be the most reliable.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates
Effect concentration:
163 mg/L

Additional information