Sodium selenate

Long-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

long-term toxicity to aquatic invertebrates

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. Effect concentrations based on measured Se concentrations. Only 3 exposure concentrations, but a clear NOEC and LOEC have been determined (factor of 2 difference between both is still more or less acceptable).

Qualifier:

no guideline followed

Principles of method if other than guideline:

In this study, first instar juveniles of the marine amphipod species Allorchestes compressa were exposed for 4 weeks to waterborne selenium in a flow-through system. Both survival and growth were monitored.

GLP compliance:

not specified

Analytical monitoring:

yes

Details on sampling:

Water samples were taken at intervals for Se analysis (frequency not reported).

Vehicle:

no

Details on test solutions:

see test conditions

Test organisms (species):

other: Allorchestes compressa

Details on test organisms:

TEST ORGANISM
- Source: three Victorian coastal locations
- Age at test initiation: first instar juveniles
- Feeding during test: yes
- Food type: decaying seagrass
- Amount: 1-2 g per amphipod to maintain an excess of food throughout exposure

Test type:

flow-through

Water media type:

saltwater

Limit test:

no

Total exposure duration:

4 wk

Hardness:

not reported

Test temperature:

20°C

pH:

not reported

Dissolved oxygen:

not reported

Salinity:

32-35 g/L

Nominal and measured concentrations:

Control + 44, 93, 193 µg Se/L (measured)

Details on test conditions:

TEST SYSTEM
- Test vessel: large flow-through glass seawater tanks
- Flow-through system (2-3 times the tank volume per day)
- No. of organisms per vessel: 40-50
- No. of vessels per treatment: 4
- No. of vessels per control: 4

TEST MEDIUM / WATER PARAMETERS
- Seawater
- Salinity: 32-35 g/L.

OTHER TEST CONDITIONS
- Photoperiod: 14h:10h light:dark cycle
- Light intensity: 15 µE/m2/s

Duration:

4 wk

Dose descriptor:

NOEC

Effect conc.:

44 µg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

element

Remarks:

Se

Basis for effect:

other: survival and growth

Duration:

4 wk

Dose descriptor:

LOEC

Effect conc.:

93 µg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

element

Remarks:

Se

Basis for effect:

other: survival and growth

Reported statistics and error estimates:

One-way ANOVA

Validity criteria fulfilled:

yes

Conclusions:

Klimisch 2 study on the chronic toxicity of waterborne sodium selenite to juveniles of the marine amphipod species Allorchestes compressa. The 4-week NOEC and LOEC based on survival and growth were 44 and 93 µg Se/L, repectively.

Reference 2

Endpoint:

long-term toxicity to aquatic invertebrates

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. A single disadvantage is that the test was not started with neonates.

Qualifier:

no guideline followed

Principles of method if other than guideline:

In this study 2-month-old Hyalella azteca were exposed for 24 days to waterborne Se in a static renewal system. Reproduction was monitored.

GLP compliance:

not specified

Analytical monitoring:

yes

Details on sampling:

Selenium concentrations in the test solution were monitored regularly.

Vehicle:

no

Details on test solutions:

see test conditions

Test organisms (species):

other: Hyalella azteca

Details on test organisms:

TEST ORGANISM
- Source: the amphipods were obtained from cultures maintained by US EPA's Western Fish Toxicology Station in Corvallis, OR.
- Age at study initiation (mean and range, SD): 2 months old
- Length at study initiation (length definition, mean, range and SD): 2 mm
- Feeding during test: yes
- Type of food: ground rabbit chow
- Frequency of feeding: every second and third day
- The amount of food provided was consumed within 1 h

ACCLIMATION
- Acclimation period: 9 months

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

24 d

Hardness:

132.72 +/- 24.30 mg CaCO3/L

Test temperature:

25°C

pH:

8.6

Dissolved oxygen:

7.67 +/- 0.50 mg/L

Salinity:

not applicable

Nominal and measured concentrations:

Nominal: Control + 50, 100, 200, 300, 400 µg Se/L.
Measured: within 95% of nominal.

Details on test conditions:

TEST SYSTEM
- Test vessel: 500-mL polyethylene jars containing 400 mL of medium
- Renewal rate of test solution (frequency/flow rate): renewal after 48 h
- No. of organisms per vessel: 10 amplexed pairs (20 animals) per replicate
- No. of vessels per concentration (replicates): 4 replicates
- No. of vessels per control (replicates): 4 replicates

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: University of California at Davis well water.
- Alkalinity = 301.85 mg CaCO3/L
- Sulfate = 12.92 mg/L

OTHER TEST CONDITIONS
- Photoperiod: 16L:8D

Duration:

24 d

Dose descriptor:

NOEC

Effect conc.:

100 µg/L

Nominal / measured:

nominal

Conc. based on:

element

Remarks:

Se

Basis for effect:

reproduction

Remarks on result:

other: second brood release - nominal concentrations were used since measured were within 95% of nominal

Duration:

24 d

Dose descriptor:

LOEC

Effect conc.:

200 µg/L

Nominal / measured:

nominal

Conc. based on:

element

Remarks:

Se

Basis for effect:

reproduction

Remarks on result:

other: second brood release

Reported statistics and error estimates:

A one-way ANOVA was used to determine the effect of selenium on the number of off-spring (from the second brood) per surviving female. When this effect was significant (P less than 0.05), Duncan's multiple comparison of means was used to compare the reproduction response between treatments.

Validity criteria fulfilled:

yes

Conclusions:

Klimisch 2 study on the chronic effects of waterborne sodium selenite on reproduction of Hyalella azteca. The 24-day NOEC and LOEC based on reproduction were 100 and 200 µg Se/L, respectively.

Reference 3

Endpoint:

long-term toxicity to aquatic invertebrates

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: see 'Remark'

Remarks:

Well performed study. Effect concentrations based on measured concentrations. A Klimisch 2 score was assigned because no official guideline was followed, because no information was given with regard to the control criteria, and because field water was used as dilution water (uncontaminated).

Qualifier:

no guideline followed

Principles of method if other than guideline:

In this study, juvenile brine shrimp (Artemia franciscana) were exposed for 28 days to a control or one of 5 waterborne Se concentrations in an intermittent flow-through system. After 11 days, 6 adult pairs per test concentration were monitored. Both mortality and reproduction were studied.

GLP compliance:

not specified

Analytical monitoring:

yes

Details on sampling:

Water samples from each exposure treatment were collected on a weekly basis.

Vehicle:

no

Details on test solutions:

see test conditions

Test organisms (species):

other: Artemia franciscana (brine shrimp)

Details on test organisms:

TEST ORGANISM
- Common name: brine shrimp
- Age at start of testing: < 24 h old
- Feeding during test: yes
- Food type: marine algae from the genus Platymonas
- Frequency: daily
- Amount: 2 mL of a 500,000 cells/mL stock

Test type:

other: Intermittent flow-through

Water media type:

saltwater

Limit test:

no

Total exposure duration:

28 d

Hardness:

not reported

Test temperature:

25°C

pH:

7.9-8.4

Dissolved oxygen:

1.8-6.0 mg/L

Salinity:

80-102 g/L

Nominal and measured concentrations:

Control + 3.8-7.5-15-30-60 mg Se/L (nominal)

Details on test conditions:

TEST SYSTEM
- Test vessel: 600-mL beakers with 400 mL of test solution
- Renewal rate of test solution (frequency/flow rate): intermittent flow-through, no details reported
- No. of organisms per vessel: after 11 days, 1 adult pair per vessel
- No. of vessels per concentration (replicates): 6

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Great Salt Lake water collected from the shoreline on the north side of Antelope Island, a location well removed from anthropogenic inputs.
- TOC = 35-49 mg/L.
- DOC = 34.8-40 mg/L
- Salinity: 80-102 g/L
- Sulfate: 5800 mg/L

Duration:

28 d

Dose descriptor:

NOEC

Effect conc.:

15 000 µg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

element

Remarks:

Se

Basis for effect:

reproduction

Duration:

28 d

Dose descriptor:

LOEC

Effect conc.:

38 000 µg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

element

Remarks:

Se

Basis for effect:

reproduction

Duration:

28 d

Dose descriptor:

NOEC

Effect conc.:

74 000 µg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

element

Remarks:

Se

Basis for effect:

mortality

Duration:

28 d

Dose descriptor:

LOEC

Effect conc.:

> 74 000 µg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

element

Remarks:

Se

Basis for effect:

mortality

Details on results:

28 d LOEC of > 74000 µg Se/L based on mortality.
28 d LOEC of 38000 µg Se/L based on reproduction.

Reported statistics and error estimates:

If assumptions of normality and homogeneity were met, ANOVA was used. Otherwise, the nonparametric Kruskal-Wallis test was used.

Validity criteria fulfilled:

yes

Conclusions:

Klimisch 2 study on the chronic toxicity of sodium selenate to Artemia franciscana (brine shrimp). The 28-day NOEC values for mortality and reproduction were 74000 and 15000 µg Se/L, respectively. The 28-day LOEC values for mortality and reproduction were > 74000 and 38000 µg Se/L, respectively.

Reference 4

Endpoint:

long-term toxicity to aquatic invertebrates

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. Effect concentrations based on measured Se concentrations.

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 211 (Daphnia magna Reproduction Test)

Deviations:

yes

Remarks:

longer test duration

GLP compliance:

not specified

Analytical monitoring:

yes

Details on sampling:

Water samples were taken from each treatment at the beginning and end of each weekly static renewal period.

Vehicle:

no

Details on test solutions:

see test conditions

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Strain/clone: Straus
- Source: from a laboratory stock culture
- Age at test initiation: neonates < 24 h old
- Length at test initiation: 0.590-0.630 mm
- Feeding during test
- Food type: Animals were fed a suspension of Selenastrum capricornutum (daily addition of 12-19 x 10^6 cells).
- Frequency: daily

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

32 d

Hardness:

Water hardness = 129.5 mg CaCO3/L

Test temperature:

Temperature = 20°C

pH:

pH = 8.15-8.40

Dissolved oxygen:

Dissolved oxygen = 9.3 mg/L

Salinity:

not applicable

Nominal and measured concentrations:

Control + 0.25-0.5-1.0-1.5-2.0 mg/L (nominal).

Details on test conditions:

TEST SYSTEM
- Test vessel: 250-mL beakers, 200 mL fill-volume
- Type of flow-through (e.g. peristaltic or proportional diluter): static renewal
- Renewal rate of test solution (frequency/flow rate): weekly
- No. of animals per replicate: 2 (one removed after 1 week)
- No. of vessels per concentration (replicates): 20
- No. of vessels per control (replicates): 20

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: reconstituted hard water
- Alkalinity: 116.7 mg CaCO3/L

OTHER TEST CONDITIONS
- Light intensity and light cycle: reduced continuous illumination

Duration:

32 d

Dose descriptor:

NOEC

Effect conc.:

1 620 µg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

element

Remarks:

Se

Basis for effect:

reproduction

Remarks on result:

other: 6-brood total

Duration:

32 d

Dose descriptor:

LOEC

Effect conc.:

2 180 µg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

element

Remarks:

Se

Basis for effect:

reproduction

Remarks on result:

other: 6-brood total

Duration:

32 d

Dose descriptor:

NOEC

Effect conc.:

1 050 µg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

element

Remarks:

Se

Basis for effect:

growth

Remarks on result:

other: body weight

Duration:

32 d

Dose descriptor:

LOEC

Effect conc.:

1 620 µg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

element

Remarks:

Se

Basis for effect:

growth

Remarks on result:

other: body weight

Reported statistics and error estimates:

Two nonparametric methods were used. To determine differences due to treatment the Kruskal-Wallis method was used. To determine which treatments differed, the Dunns multiple comparison method was used.

Validity criteria fulfilled:

not applicable

Conclusions:

Klimisch 2 study on the chronic toxicity of waterborne sodium selenate to Daphnia magna. The 32-day NOEC and LOEC based on reproduction (6-brood total) were 1620 and 2180 µg Se/L, respectively. The 32-day NOEC and LOEC based on growth (body weight) were 1050 and 1620 µg Se/L, respectively.

Reference 5

Endpoint:

long-term toxicity to aquatic invertebrates

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. LC50 values based on measured Se concentrations.

Reason / purpose for cross-reference:

reference to same study

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 211 (Daphnia magna Reproduction Test)

GLP compliance:

not specified

Analytical monitoring:

yes

Details on sampling:

- Water samples were taken at least weekly from each treatment for Se analysis.
- Seven to ten surviving daphnids were sampled from each replicate exposure beaker at the end of the 21-d exposure for Se analysis.

Vehicle:

no

Details on test solutions:

see test conditions

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Source: from a laboratory culture, < 24-h old
- Feeding during test: yes
- Food type: yeast-trout chow mixture and algal cells (Selenastrum capricornutum).
- Amount: 10 mg yeast-trout chow mixture and 6 x 10^7 algal cells (Selenastrum capricornutum).

Test type:

flow-through

Water media type:

freshwater

Limit test:

no

Total exposure duration:

21 d

Hardness:

138.1 mg CaCO3/L

Test temperature:

22 deg C

pH:

7.93

Dissolved oxygen:

6.8 mg/L

Salinity:

not applicable

Nominal and measured concentrations:

Control + 0.094-0.188-0.375-0.750-1.5 mg/L. (measured)

Details on test conditions:

TEST SYSTEM
- Test vessel: 1-L glass beakers
- Flow-through system (daily volume addition = 3.4)
- No. of organisms per vessel: 10
- No. of replicates per concentration: 4
- No. of replicates per control: 4

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Reconstituted San Joaquin River water
- Sulfate: 73.3 mg/L
- Chloride: 8.29 mg/L
- Alkalinity: 69.0 mg CaCO3/L

OTHER TEST CONDITIONS
- Photoperiod: 16:8 h light:dark

Duration:

21 d

Dose descriptor:

NOEC

Effect conc.:

85 µg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

element

Remarks:

Se

Basis for effect:

growth

Remarks:

body weight

Duration:

21 d

Dose descriptor:

LOEC

Effect conc.:

156 µg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

element

Remarks:

Se

Basis for effect:

growth

Remarks:

body weight

Duration:

21 d

Dose descriptor:

NOEC

Effect conc.:

156 µg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

element

Remarks:

Se

Basis for effect:

reproduction

Duration:

21 d

Dose descriptor:

LOEC

Effect conc.:

348 µg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

element

Remarks:

Se

Basis for effect:

reproduction

Duration:

21 d

Dose descriptor:

NOEC

Effect conc.:

711 µg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

element

Remarks:

Se

Basis for effect:

mortality

Duration:

21 d

Dose descriptor:

LOEC

Effect conc.:

1 410 µg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

element

Remarks:

Se

Basis for effect:

mortality

Details on results:

Growth (body weight):
NOEC=85 µg Se/L (21.1 mg Se/kg dw whole body)
LOEC = 156 µg Se/L (14.7 mg Se/kg dw whole body)

Reproduction (intrinsic rate of natural increase):
NOEC = 156 µg Se/L (14.7 mg Se/kg dw whole body)
LOEC = 348 µg Se/L (31.7 mg Se/kg dw whole body)

Mortality:
NOEC = 711 µg Se/L
LOEC = 1410 µg Se/L

Reported statistics and error estimates:

Effects were compared by one-way analysis of variance (ANOVA) with means separation by the least significant difference (LSD) multiple mean comparison test at alpha= 0.05. All statistical analyses were performed with Statistical Analysis System SAS program.

Validity criteria fulfilled:

yes

Conclusions:

Klimisch 2 study on the chronic toxicity of waterborne selenium (6.6:1 ratio of Se added as sodium selenate and sodium selenite) to Daphnia magna. The 21-day NOEC values for reproduction, mortality, and growth were 156, 711 and 85 µg Se/L, respectively. The 21-day LOEC values for reproduction, mortality, and growth were 348, 1410 and 156 µg Se/L, respectively. Exposure concentrations of 85, 156 and 348 µg Se/L resulted in whole body concentrations of 21.1, 14.7 and 31.7 mg Se/kg dw, respectively.

Reference 6

Endpoint:

long-term toxicity to aquatic invertebrates

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. Effect concentrations based on measured Se concentrations.

Reason / purpose for cross-reference:

reference to same study

Qualifier:

no guideline followed

Principles of method if other than guideline:

In this study, larvae of the dipteran species Chironomus riparius were exposed for 30 days to waterborne selenium in a flow-through system. Percentage emergence, emergence time and day of first emergence were monitored.

GLP compliance:

not specified

Analytical monitoring:

yes

Details on sampling:

Water samples were taken at least weekly from each treatment for Se analysis.

Vehicle:

no

Details on test solutions:

see test conditions

Test organisms (species):

other aquatic arthropod: Chironomus riparius

Details on test organisms:

TEST ORGANISM
- Source: from a laboratory culture
- Age at test initiation: < 24-h old
- Feeding during test: yes
- Food type: midges were fed suspensions of Cerophyl, Selenastrum capricornutum and Dog Treats

Test type:

flow-through

Water media type:

freshwater

Limit test:

no

Total exposure duration:

30 d

Hardness:

137.6 mg CaCO3/L

Test temperature:

22 deg C

pH:

pH = 7.98

Dissolved oxygen:

Dissolved oxygen = 6.6 mg/L

Salinity:

not applicable

Nominal and measured concentrations:

Nominal: Control + 0.375-0.750-1.5-3.0-6.0 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: 1-L beakers with 13 g of sand (mean grain size about 0.5 mm) and overlying water spiked with Se
- Flow-through system (daily volume addition = 6.0)
- No. of organisms per vessel: 50
- No. of vessels per treatment: 4
- No. of vessels per control: 4

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: reconstituted San Joaquin River water
- Sulfate = 72.6 mg/L
- Alkalinity: 71.2 mg CaCO3/L

OTHER TEST CONDITIONS
- Photoperiod: 16:8 h light:dark

Duration:

30 d

Dose descriptor:

NOEC

Effect conc.:

303 µg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

element

Remarks:

Se

Basis for effect:

other: emergence time and day of first emergence

Duration:

30 d

Dose descriptor:

LOEC

Effect conc.:

837 µg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

element

Remarks:

Se

Basis for effect:

other: emergence time and day of first emergence

Duration:

30 d

Dose descriptor:

NOEC

Effect conc.:

2 953 µg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

element

Remarks:

Se

Basis for effect:

other: % emergence

Duration:

30 d

Dose descriptor:

LOEC

Effect conc.:

6 050 µg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

element

Remarks:

Se

Basis for effect:

other: % emergence

Reported statistics and error estimates:

Effects were compared by one-way analysis of variance (ANOVA) with means separation by the least significant difference (LSD) multiple mean comparison test at alpha= 0.05. All statistical analyses were performed with Statistical Analysis System SAS program.

Validity criteria fulfilled:

not applicable

Conclusions:

Klimisch 2 study on the chronic toxicity of waterborne selenium to larvae of the dipteran species Chironomus riparius. The most sensitive endpoints were emergence time and day of first emergence, with a 30-d NOEC and LOEC of 303 and 837 µg Se/L, respectively.

Reference 7

Endpoint:

long-term toxicity to aquatic invertebrates

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. Effect concentrations based on measured Se concentrations.

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 211 (Daphnia magna Reproduction Test)

GLP compliance:

not specified

Analytical monitoring:

yes

Details on sampling:

- Samples for metal analysis were drawn into 15 ml tubes and acidified with 1 drop of 1.0 N HNO3.
- Frequency: 3 times weekly

Vehicle:

no

Details on test solutions:

see test conditions

Test organisms (species):

Daphnia magna

Details on test organisms:

- Obtained from a commercially available source (Aquatic Life Company, Minneapolis, USA)
- Neonates, 12 ± 12 h old
- Animals were fed but no information on type and amount of food was stated.

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

28 d

Hardness:

no data (hard water)

Test temperature:

20.4°C (average)

pH:

8.47 (average)

Dissolved oxygen:

7.43 mg/L (average)

Salinity:

not applicable

Nominal and measured concentrations:

Control + 0.07-0.12-0.19-0.30-0.48-0.92 mg/L.

Details on test conditions:

TEST SYSTEM
- Test vessel: 100 mL beaker, 50 mL fill volume
- Type of flow-through (e.g. peristaltic or proportional diluter): static renewal system
- Renewal rate of test solution (frequency/flow rate): three times a week
- No. of organisms per vessel: 1
- No. of vessels per concentration (replicates): 10 replicates

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Hard water from a well tapping the Jordan sandstone stratum underlying the Minneapolis-St. Paul metropolitan area. Iron was catalytically removed (0.1 mg/L).
- Alkalinity: 210 mg CaCO3/L (average)

Duration:

28 d

Dose descriptor:

NOEC

Effect conc.:

70 µg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

element

Remarks:

Se

Basis for effect:

reproduction

Duration:

28 d

Dose descriptor:

LOEC

Effect conc.:

120 µg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

element

Remarks:

Se

Basis for effect:

reproduction

Duration:

28 d

Dose descriptor:

NOEC

Effect conc.:

190 µg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

element

Remarks:

Se

Basis for effect:

mortality

Duration:

28 d

Dose descriptor:

LOEC

Effect conc.:

300 µg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

element

Remarks:

Se

Basis for effect:

mortality

Details on results:

28 d LC50 of 240 µg Se/L based on mortality.

Reported statistics and error estimates:

The data was examined by one-way analysis of variance with treatment differences separated by Dunnett's procedure (one-tailed) at alpha=0.05.

Validity criteria fulfilled:

yes

Conclusions:

Klimisch 2 study on the chronic toxicity of selenium to Daphnia magna. The study was conducted according to a procedure similar to standard procedures for reproduction toxicity tests with cladocerans. The 28-day NOEC, LOEC and LC50 for mortality were 190, 300, and 240 µg Se/L, respectively. The 28-day NOEC and LOEC for reproduction were 70 and 120 µg Se/L, respectively.

Description of key information

Reliable chronic NOEC values are available for freshwater invertebrates (range: 70 to 2953 µg Se/L) and marine invertebrates (44 to 74000 µg Se/L).

The most critical NOEC for freshwater organisms is a 28-d NOEC for reproduction of Daphnia magna from a study with H₂SeO₃. For marine invertebrates, the most critical NOEC was a 28-d NOEC of 44 µg/L for survival and growth of Allorchestes compressa obtained in a study using Na₂SeO₃ as test substance. All reliable chronic NOEC values were used for the derivation of a PNECwater based on the statistical extrapolation approach.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

70 µg/L

Marine water invertebrates

Marine water invertebrates

Effect concentration:

44 µg/L

Additional information

Reliable results are obtained from 7 different studies. These results include data from toxicity tests with H₂SeO₃, Na₂SeO₃ and Na₂SeO₄. Reliable data are available for three freshwater and two marine invertebrates. The freshwater invertebrates represented were Daphnia magna and Hyalella azteca (Crustacea), and Chironomus riparius (Insecta, Diptera). The marine invertebrates represented were Allorchestes compressa and Artemia franciscana (Crustacea). All results are based on added dissolved Se concentrations.

For freshwater invertebrates, reliable NOEC values range from 70 to 2953 µg Se/L. The lowest NOEC results from a 28-d toxicity study on reproduction of Daphnia magna, in which H₂SeO₃ was used as test substance (Kimball, 1978). The highest NOEC value represents a 30-d NOEC for % emergence of the dipteran Chironomus riparius (Ingersoll et al., 1990). In this study, a mixture of Na₂SeO₄ and Na₂SeO₃ was added in a 5.7:1 ratio (Se-based) to the exposure media.

Two studies are identified reporting reliable data for saltwater species. Ahsanullah and Brand (1985) report a 28-d NOEC of 44 µg Se/L for both survival and growth of the marine amphipod Allorchestes compressa, obtained in a study using Na₂SeO₃ as test substance. The other reliable study reports 28-d NOEC values of 15000 and 74000 µg Se/L for reproduction and mortality of brine shrimp (Artemia franciscana) (Brix et al., 2004). In this study, Na₂SeO₄ was used as test substance.

Results for dietary toxicity of Se to aquatic invertebrates can be used for the secondary poisoning assessment of Se in the aquatic food chain. Reliable NOECoral values (expressed as mg Se/kg diet) were obtained from studies in which Se was added to the diet only. Results are available for the mayfly Centroptilum triangulifer and NOEC values range from 4.2 to >40.9 mg Se/kg diet (dw).

One study was identified reporting reliable effect concentrations expressed as internal Se concentrations. Ingersoll et al. (1990) exposed D. magna for 21 days to a series of waterborne Se concentrations using a 6.6:1 mixture (Se-based) of Na₂SeO₄ and Na₂SeO₃. The 21-d NOEC for the endpoint reproduction was 156 µg Se/L or – when expressed as internal Se concentration – 14.7 mg Se/kg dw (whole body).