Sodium chlorate

Short-term toxicity to fish

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

Study generated according to generally valid and internationally accepted testing guideline and performed under GLP. No analytical monitoring was performed, only the stock solution was analyzed, but based on chronic tests it can be assumed that the test substance was stable during the test and the fish were properly exposed.

Qualifier:

according to guideline

Guideline:

other: EPA-FIFRA, guideline 72-3

Deviations:

no

GLP compliance:

yes

Analytical monitoring:

no

Vehicle:

no

Details on test solutions:

- Preparation: 600,000 mg/L stock solution was prepared by adding 1200.0 g test substance to 2000 ml deionized water. Appropriate amounts of stock were added directly to dilution water by a proportional diluter.

Test organisms (species):

Cyprinodon variegatus

Details on test organisms:

- Supplier: The aquatic research organisms division of resource analysts, Inc., Hampton, New Hampshire
- Wild caught: No
- Age/weight/loading: juvenile
- Feeding: fish food (EnviroSystems lot number TM02) once or twice daily
- Pretreatment: acclimatized for more than 7 days under test conditions.
- Feeding during test: no, feeding stopped 48 hours prior to the test

Test type:

flow-through

Water media type:

saltwater

Limit test:

no

Total exposure duration:

96 h

Test temperature:

21.8-22.9 °C

pH:

7.6-7.8

Dissolved oxygen:

7.4-8.1 mg/L

Salinity:

15-17 ppt

Nominal and measured concentrations:

Nominal concentrations: 0, 140, 240, 380, 600, 1000 mg/L

Details on test conditions:

DILUTION WATER:
- Source: unfiltered sea water collected from Atlantic ocean in Hampton, New Hampshire
- Aeration: Yes
- Salinity: 16 ppt (parts per thousand)
- pH: 7.6
- Holding water: same as dilution water

TEST SYSTEM:
- Test type: 7.8 media exchanges per 24 hours in each test vessel.
- Exposure vessel type: 20 L glass aquaria that contained 15 L of test solution
- Number of replicates, fish per replicate: 2, 10
- Intensity of irradiation: cool white fluorescent lights with an intensity of 12 µEs/m2
- Photoperiod: 16 hours photoperiod daily

Reference substance (positive control):

no

Duration:

96 h

Dose descriptor:

NOEC

Effect conc.:

1 000 mg/L

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

> 1 000 mg/L

Details on results:

Measured concentration of the stock solution was 600,000 mg/L

Effect data (Mortality): In the control and in all test concentrations no mortality and no sublethal effects were observed.

Reported statistics and error estimates:

No statistics could be performed because greater than 50% survival occurred in all test concentrations.

Validity criteria fulfilled:

no

Remarks:

the test substance concentration could not be monitored

Conclusions:

only the stock solution could be analyzed, but based on chronic tests for which chemical analyses were performed it can be assumed that the test concentrations were stable and that the fish were exposed properly. No fish died during the test, therefore the 96h-LC50 is greater than 1000 mg/l and the NOEC is 1000 mg/l.

Executive summary:

The acute toxicity of sodium chlorate to the sheepshead minnow, Cyprinodon variegatus, is described in this final report. The test

was conducted for Albright and Wilson Americas for 96 hours during February 19 to 23, 1991, at the EnviroSystems Division of Resource Analysts, Inc. in Hampton, New Hampshire. It was conducted by Peter Kowalski, Ellen Stanford, Jeanne Magazu, Robert Boeri, and Timothy Ward according to the protocol developed for EnviroSystems Study Number 90115-DE. The analytical portion of this study was conducted under the supervision of Gloria Switalski. Sodium chlorate (reported purity >99% active ingredient) was supplied by the sponsor.

The test was performed under flow-through conditions with five concentrations of test substance and a dilution water control at a temperature of 22 ± 1°C. The dilution water was unfiltered natural seawater collected at Hampton, New Hampshire. Mean nominal concentrations of sodium chlorate were: 0 mg/L (control), 140, 240, 380, 600, and 1,000 mg/L. Nominal concentrations were used for all calculations.

Organism used in the test were procured from a commercial supplier (Aquatic Research Organisms, Hampton, New Hampshire) and acclimated at EnviroSystems under test conditions for more than 7 days. After 96 hours of exposure the control organisms had an average wet weight (blotted dry) of 0.70 g. All animals were in good condition at the beginning of the study.

Exposure of sheepshead minnow to the test substance resulted in a 96 hour LC50 greater than 1,000 mg/L sodium chlorate. The 96 hour no observed effect concentration was 1,000 mg/L sodium chlorate.

Reference 2

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

Study generated according to valid and internationally accepted testing guideline and performed under GLP. No chemical analyses were prformed on the test solution, only the stock solution could be analyzed. Because of analytical results from chronic tests it can be assumed that the test concentrations were stable and the fish were exposed properly.

Qualifier:

according to guideline

Guideline:

EPA OPP 72-1 (Fish Acute Toxicity Test)

GLP compliance:

yes

Analytical monitoring:

no

Details on sampling:

Analysis conducted on stock only.

Vehicle:

no

Details on test solutions:

Preparation: 600,000 mg/L stock solution was prepared by adding 1200.0 g test substance to 2000 ml deionized water. Appropriate amounts of stock were added directly to dilution water by a proportional diluter. The dilution water was filtered natural groundwater collected at Hampton, New Hampshire.

Test organisms (species):

Oncorhynchus mykiss (previous name: Salmo gairdneri)

Details on test organisms:

Supplier: Aquatic Research Organisms, Hampton, New Hampshire
- Wild caught: No
- Age/weight/loading: juvenile, 0.57 g on average, 0.38 g/L
- Feeding: fish food (EnviroSystems lot number TM02) once or twice daily
- Pretreatment: acclimatized for 14 days under test conditions.
- Feeding during test: no, feeding stopped 48 hours prior to the test

Test type:

flow-through

Water media type:

freshwater

Limit test:

no

Total exposure duration:

96 h

Post exposure observation period:

Pretreatment: acclimatized for 14 days under test conditions

Test temperature:

11.0-11.6 °C

pH:

6.8-7.3

Dissolved oxygen:

9.0-9.8 mg/L

Nominal and measured concentrations:

0 mg/L (control), 150 1 240, 380, 600, and 1,000 mg/L. (Nominal)

Details on test conditions:

- Test type: flow-through, 9.0 media exchanges per 24 hours in each test vessel.
- Exposure vessel type: 20 L glass aquaria that contained 15 L of test solution
- Number of replicates, fish per replicate: 2, 10
- Conductivity: 490-1200 µmhos/cm (equal to µS/cm) at the start of the test and 530-680 µmhos/cm (equal to µS/cm) at the end
- Intensity of irradiation: cool white fluorescent lights with an intensity of 12 µEs/m2
- Photoperiod: 16 hours photoperiod daily
- Nominal test concentrations: 0, 150, 240, 380, 600, 1000 mg/L. Measured concentration of the stock solution was 630,000 mg/L

Dilution water:
– Source: groundwater collected from wells in Hampton, New Hampshire
- Aeration: Yes
- Hardness: 48 mg CaCO3/L
- pH: 6.8
- Conductance: 490 µmhos/cm (equal to µS/cm)
- Holding water: same as dilution water

Reference substance (positive control):

no

Duration:

96 h

Dose descriptor:

NOEC

Effect conc.:

600 mg/L

Nominal / measured:

nominal

Basis for effect:

mortality (fish)

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

> 1 000 mg/L

Details on results:

mortality and loss of equilibrium, erratic swimming, loss of reflex, excitability, discoloration or change in behavior.
- Mortality: At 72 hours 1 fish was dead in 1000 mg/l
- Affected: At 72 hours 2 and 4 fish were lethargic in the 2 replicates of 1000 mg/l. At 96 hours only 1 and 2 fish respectively showed these effects
in the same concentration.
- No effects were observed in the control, all fish were normal.

Results with reference substance (positive control):

Not Reported

Reported statistics and error estimates:

No statistics could be performed because greater than 50% survival occurred in all test concentrations.

Validity criteria fulfilled:

no

Remarks:

The test concentrations could not be monitored, only the stock solution was analyzed.

Conclusions:

Study performed to EPA guidelines under flow through conditions with GLP accreditation. Stocks were analysed but analysis in the test media was not possible to interference. The stock recovery was 105%. Due to the test substance stability and the fact that the solution is continually renewed and
providing the automatic diluting system used was working accurately the nominal concentrations can be considered reliable. The LC50 of
>1000mg/l is considered reliable without major restrictions.

Executive summary:

Exposure of rainbow trout to the test substance resulted in a 96 hour LC50 greater than 1,000 mg/L sodium chlorate. The 96 hour no observed effect concentration was 600 mg/L sodium chlorate.

Description of key information

The LC50 for fresh water fish is greater than 1000 mg/l.

Similar to fresh water fish tests, the LC50 of sodium chlorate to marine fish was also greater than the highest test concentration of 1000 mg/l.

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Effect concentration:

1 000 mg/L

Marine water fish

Marine water fish

Effect concentration:

1 000 mg/L

Additional information

Seven acute toxicity studies were found for fresh water fish of which four are valid and one is valid with restrictions (Toussaint et al.; 2001) because the test was not performed according to standard test protocol. One valid test on marine fish was also found.

For all studies LC50s >1000 mg/l were observed. In two studies (Ward and Boeri (1991a) and (1991b)) with Oncorhynchus mykiss and Lepomis macrochirus chemical analysis of the stock solution was performed. The measured concentrations were 105 and 103% of the nominal concentration and therefore the nominal test concentrations were used to derive the endpoints. Except of the stock solution, no chemical analysis was performed during the test. But it was considered that the concentration of sodium chlorate was stable during the test.

The LC50 for fresh water fish is greater than 1000 mg/l.

Similar to fresh water fish tests, the LC50 of sodium chlorate to marine fish (Ward and Boeri, 1991c) was also greater than the highest test concentration of 1000 mg/l.