Sodium selenate

Short-term toxicity to fish

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

short-term toxicity to fish

Type of information:

migrated information: read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Well performed study. Effect concentrations based on measured Se concentrations.

Qualifier:

according to guideline

Guideline:

EPA OPP 72-1 (Fish Acute Toxicity Test)

GLP compliance:

not specified

Analytical monitoring:

yes

Details on sampling:

-Frequency: Three to four times during bioassay
- Sampling method: Upon collection, samples of water were filtered through Whatman No. 1 paper to remove debris and acidified to insure toxicant stability

Vehicle:

no

Details on test solutions:

see test conditions

Test organisms (species):

Pimephales promelas

Details on test organisms:

TEST ORGANISM
- Common name: Fathead minnow
- Source: Cultured in laboratory from brood stock obtained from US EPA's National Water Quality Laboratory in Duluth, Minnesota, USA
- Age at study initiation (mean and range, SD): 1 day (yolk sac fry) or 3 months (juveniles)
- Length at study initiation: 5 mm (yolk sac fry) of 20.7 mm (juveniles)
- Weight at study initiation: 0.085 g (juveniles)
- Feeding during test: No

ACCLIMATION
- Acclimation period: 3 days prior to exposure
- Fish were not fed during the acclimation period

Test type:

flow-through

Water media type:

freshwater

Limit test:

no

Total exposure duration:

96 h

Hardness:

151 mg /L as CaCO3

Test temperature:

24.7 ± 0.4 °C

pH:

7.80 ± 0.09

Dissolved oxygen:

7.1 ± 0.6 mg/L

Salinity:

not applicable

Nominal and measured concentrations:

Control + 5 exposure concentrations up to 54 mg SeO2/L

Details on test conditions:

TEST SYSTEM
- Test vessel: 30.5x30.5x30.5 cm glass chambers containing 16.5 L of test solution
- Type of flow-through (e.g. peristaltic or proportional diluter): 2-L proportional diluters
- Renewal rate of test solution (frequency/flow rate): 90% renewal in 9 h
- No. of organisms per vessel: 10
- No. of vessels per concentration (replicates): 2
- No. of vessels per control (replicates): 2

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: no data
- Alkalinity: 167 ± 4 mg/L as CaCO3
- Sulfate: 8.6 mg/L

OTHER TEST CONDITIONS
- Photoperiod: 12:12 (light:dark)
- Light intensity: 1010 lux

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

2 060 µg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

element

Remarks:

Se

Basis for effect:

mortality (fish)

Remarks on result:

other: 1-d-old yolk sac fry

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

5 190 µg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

element

Remarks:

Se

Basis for effect:

mortality (fish)

Remarks on result:

other: 3-month-old juveniles

Reported statistics and error estimates:

Probit analysis or Litchfield-Wilcoxon in case of only one partial kill.

Conclusions:

Reliable (Klimisch 1) study on the toxicity of selenium dioxide to Pimephales promelas (fathead minnow). The 96-h LC50 values for 1-d-old yolk sac fry and 3-month-old juveniles were 2060 and 5190 µg Se/L, respectively.

Reference 2

Endpoint:

short-term toxicity to fish

Type of information:

migrated information: read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Well performed study. Not entirely clear how many replicates were used. Good reproducibility among tests with different test animals from about the same age. pH and sulfate concentration not reported.

Qualifier:

according to guideline

Guideline:

other: ASTM methods for acute testing

GLP compliance:

not specified

Analytical monitoring:

yes

Details on sampling:

- Frequency: At the end of the test
- Sampling method and storage: 100 mL water samples were randomly taken from two to four beakers after the test. Samples were acidified by addition of 1 mL HCl and frozen (-18°C) until analysis.

Vehicle:

no

Details on test solutions:

see test conditions

Test organisms (species):

Morone saxatilis

Details on test organisms:

TEST ORGANISM
- Common name: Striped bass
- Source: Florida Game and Freshwater Fish Commission (larvae) and California Department of Fish and Game (eggs)
- Age at study initiation (mean and range, SD): 24-32 days post-hatch
- Feeding during test: no

Test type:

static

Water media type:

brackish water

Limit test:

no

Total exposure duration:

96 h

Hardness:

750-830 mg/L as CaCO3

Test temperature:

17 °C

pH:

No data

Dissolved oxygen:

Near saturation

Salinity:

reconstituted brackish water, salinity: 5 g/L

Nominal and measured concentrations:

Control + seven exposure concentrations ranging from 1 to 6 mg Se/L

Details on test conditions:

TEST SYSTEM
- Test vessel: 2-L glass beakers containing 1.5 L of test solution
- No. of organisms per vessel: 20
- No. of vessels per concentration (replicates): not reported
- No. of vessels per control (replicates): not reported

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: reconstituted brackish water (dechlorinated tap water brought to 5 ppt salinity by addition of Instant Ocean)
- Alkalinity: 38.5 - 40.5 mg/L as CaCO3

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

3 300 µg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

element

Remarks:

Se

Basis for effect:

mortality (fish)

Remarks on result:

other: Florida fish, 25 days post-hatch

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

3 900 µg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

element

Remarks:

Se

Basis for effect:

mortality (fish)

Remarks on result:

other: Florida fish, 32 days post-hatch

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

3 400 µg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

element

Remarks:

Se

Basis for effect:

mortality (fish)

Remarks on result:

other: California fish, 24 days post-hatch

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

3 800 µg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

element

Remarks:

Se

Basis for effect:

mortality (fish)

Remarks on result:

other: California fish, 31 days post-hatch

Reported statistics and error estimates:

Probit analysis or moving average method

Conclusions:

Reliable (Klimisch 2) study on the toxicity of sodium selenite to Morone saxatilis (striped bass). The 96-h LC50 values ranged from 3300 to 3900 µg Se/L, the lowest being obtained in the test started with 25-d post-hatch larvae from a Florida hatchery.

Description of key information

The most critical LC50 for freshwater fish is a 96-h LC50 for SeO₂ for fathead minnow (Pimephales promelas) of 2060 µg Se/L.

The most critical LC50 for marine fish is a 96-h LC50 of 3300 µg Se/L for the anadromous fish species Morone saxatilis (striped bass) obtained from a test in brackish water with Na₂SeO₃.

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Effect concentration:

2 060 µg/L

Marine water fish

Marine water fish

Effect concentration:

3 300 µg/L

Additional information

For acute toxicity to fish, reliable data are available for SeO₂, Na₂SeO₃ and Na₂SeO₄ and for 8 freshwater species from 6 different families (Pimephales promelas, Carassius auratus and Notemigonus crysoleucas (Cyprinidae), Jordanella floridae (Cyprinodontidae), Lepomis macrochirus (Centrarchidae), Ictalurus punctatus (Ictaluridae), Salvelinus fontinalis (Salmonidae), Stizostedion vitreum (Percidae)) and 2 marine species (from 2 families: Pagrus major (Sparidae), and Morone saxatilis (Moronidae)). All results are based on added dissolved elemental Se concentrations.

For freshwater species, the LC50 values range from 2060 to 28460 µg Se/L. The lowest LC50 represents a 96-h LC50 for SeO₂ for fathead minnow, Pimephales promelas (Cardwell et al., 1976). The highest LC50 is a 96-h LC50 for bluegill (Lepomis macrochirus) from a toxicity test from the same study with the same test substance.

For brackish/saltwater species, reliable LC50 values are found between 3300 and 76000 µg Se/L. The lowest LC50 is a 96-h LC50 for the anadromous fish species Morone saxatilis (striped bass) resulting from a toxicity test in brackish water with Na₂SeO₃ as test substance (Chapman, 1992). The highest LC50 represents a 96-h LC50 for red seabream (Pagrus major) obtained from a toxicity test in natural filtered uncontaminated seawater with Na₂SeO₄ as test substance (Takayanagi, 2001).

For freshwater fish, the data are inconclusive with regard to the question whether tetravalent selenium compounds (SeO₂ and Na₂SeO₃) are more toxic than selenate compounds.

For marine fish however, data are available from two different studies in which a single fish species was exposed to either selenite or selenate. These data suggest that selenite is more toxic than selenate to the two fish species under consideration.