Short-term toxicity to aquatic invertebrates.009

Short-term toxicity to aquatic invertebrates.009

Administrative data

Purpose flag:

key study

Study result type:

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

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

Study generated according to valid , internationally accepted testing guideline and was performed
under GLP.
No chemical analyses was performed on the test concentrations, only the stock solution could be analyzed. From chronic tests with chemical analyses it can be assumed that the test concentrations were stable and the animals were exposed properly.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1991

Report Date:

1991

Materials and methods

Test guideline

Qualifier:

according to

Guideline:

EPA OPP 72-2 (Aquatic Invertebrate Acute Toxicity Test)

GLP compliance:

yes

Test materials

Identity of test material same as for substance defined in section 1 (if not read-across):

no

Test material identityopen allclose all

Test material identity 1

Identifier:

CAS number

Identity:

7775-09-9

Test material identity 2

Identifier:

EC number

Identity:

231-887-4

Test material identity 3

Identifier:

EC name

Identity:

sodium chlorate

Details on test material:

Purity: >99%

Analytical monitoring:

no

Vehicle:

no

Details on test solutions:

- Preparation: 600.0 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

Test organisms (species):

Daphnia magna

Details on test organisms:

- Supplier: Aquatic Research Organisms, Hampton, New Hampshire 
- Age: less than 24 hours 
- Feeding: yeast/trout chow, and/or Selenastrum capricornutum daily 
- Pretreatment: acclimatized for 14 days under test conditions. 
- Feeding during test: No

Study design

Test type:

flow-through

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Test conditions

Test temperature:

19.5-20.9 °C

pH:

7.3-7.7

Dissolved oxygen:

8.5-9.0 mg/L

Nominal and measured concentrations:

Nominal test concentrations: 0, 150, 240, 380, 600, 1000 mg/L

Details on test conditions:

DILUTION WATER:
- Source: groundwater collected from wells in Hampton, New Hampshire 
- Aeration: Yes 
- pH: 7.6
- Hardness: 180 mg CaCO3/L 
- Conductance: 670 µmhos/cm (equal to µS/cm) 
- Holding water: same as dilution water
- flow-through, 8.8 media exchanges per 24 hours in each test vessel
- Exposure vessel: 20 liter glass aquaria that contained 15 liter of test solution. 
- 20 daphnids were confined in two groups of 10 in cages consisting of glass and Nitex screen. 
- Number of replicates, individuals per replicate: 2, 10
- Conductance: 620-1500 µmhos/cm (equal to µS/cm)
- Intensity of irradiation: cool white fluorescent lights with an intensity of 13 µEs/m2 
- Photoperiod: 16 hours photoperiod daily
- TEST PARAMETER: immobilization and sublethal effects

Reference substance (positive control):

no

Results and discussion

Effect concentrationsopen allclose all

Effect concentrations 1

Duration:

48 h

Endpoint:

NOEC

Effect conc.:

1 000 mg/L

Effect concentrations 2

Duration:

48 h

Endpoint:

EC50

Effect conc.:

> 1 000 mg/L

Details on results:

- 24 hours: 1 organism died in 1000 mg/l 
- 48 hours: 1 organism died in 150 mg/l and 1 in 240 mg/l 
- No other sublethal effects were observed. 
- Control: No affected or immobile organisms were observed
- The replicates mentioned in the report are no true replicates because the two cages were placed in the same aquarium.

Reported statistics and error estimates:

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

Applicant's summary and conclusion

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 within specified limits. 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:

The acute toxicity of sodium chlorate to the daphnid, Daphnia magna, is described in this final report. The test was conducted for Albright and Wilson Americas for 48 hours during March 5 to March 7, 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 90144-AW. 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 20 ± 1°C. The dilution water was filtered natural groundwater collected at Hampton, New Hampshire. Nominal concentrations of sodium chlorate were: 0 mg/L (control), iSO, 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 14 days. After 48 hours of exposure the control organisms had an average wet weight (blotted dry) of 0.0006 g. All animals were in good condition at the beginning of the study. to mg/L hQYJ"

Exposure of daphnids LC50 greater than 1,000 concentration. The 48 hour no observed effect concentration was

1,000 mg/L sodium chlorate.

Validity criteria fulfilled:

no

Remarks:

the test concentrations were not analyzed, only for the stock concentration chemical analyses was performed.