Cesium fluoroaluminate

Short-term toxicity to fish

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Study initiation date: 25/07/2013, study completion date: 19/12/2013

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

GLP compliance:

yes

Specific details on test material used for the study:

- Test substance code: RHOD20130507-0708
- Expiry date: 2014/06

Analytical monitoring:

yes

Details on sampling:

- Sampling method: For the analysis of the Al concentration, 10 mL of test solutin was taken from each test vessel before and after renewal of the test solutions. In addition, the background concentration of cesium was measured one in test water (blank control) at the beginning of the test.
- Sample storage conditions before analysis: The samples were analyzed directly without storage.

Vehicle:

no

Details on test solutions:

Range Finding Test: An amount of 0.6027 g test substance was dissolved in 500 mL deionized water to prepare the stock solution with a nominal concentration of 1.2 g/L. The stock solution was clear and no precipitate was visible. During the range-finding test a white precipitation was observed in the test solutions of the treatment groups. The test substance (molecular formula: CsAlF4) contains aluminum (Al) element, so the precipitation could result from the formation of low soluble salts, i.e., the reaction product between aluminum and anions present in the test water. Thus, a 24h semi-static test was performed to maintain the concentration of the test substance as far as possible.

Final limit test: The test substance was dissolved in deionized water to prepare the stock solution with a nominal concentration of 1 g/L. The stock solution was clear and no precipitate was visible. The test solutions were prepared by dilution of the stock solution with test water. The stock solution used in the limit test was renewed daily.

Test organisms (species):

other: Gobiocypris rarus

Details on test organisms:

TEST ORGANISM
- Common name: Gobiocypris rarus
- Source: Bioassay and Safety Assessment Lab, Shanghai Academy of Public Measurement.
- Length at study initiation: 2.2 ± 0.2 cm (Mean ± SD)
- Weight at study initiation: 0.17 ±0.04 g (Mean ± SD
- Feeding during test: No

ACCLIMATION
- Acclimation period: 14 days
- Acclimation conditions: temperature 21-25°C and constant within a range of 2°; pH 6.0-8.5; Dissolved oxygen concentration: > 80% (ASV); Photoperiod: Light/Dark = 12 hours/12 hours; The test water used was tap water dechlorinated by activated carbon and sterilized by UV lamp
- Feeding frequency: fish were fed daily until 24 hours before the test was started.
- Health during acclimation (any mortality observed): No diseases were observed during the acclimation period; No mortality was present within the 7 days before the start of the test.

Test type:

semi-static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

96 h

Post exposure observation period:

None

Hardness:

Total hardness: 155 mg CaCO3/L

Test temperature:

Measured from 22.3 to 23.9°C during the final limit test.

pH:

Measured from 7.00 to 8.13 during the final limit test.

Dissolved oxygen:

Measured from 72.5 to 91.2 % ASV during the final limit test.

Salinity:

No data

Nominal and measured concentrations:

Range-finding test: Three nominal concentrations of 1.2, 12.0 and 120 mg/L.
Limit test: Nominal concentration of 120 mg/L (the time-weighted mean concentration of Al was 7.20 mg/L).

Details on test conditions:

TEST SYSTEM
- Test vessel: 5L glass tanks were used containing 4L test solution
- Test method: semi-static
- Aeration: no data
- Renewal rate of test solution: semi-static and the frequency of renewal was every 24h
- No. of organisms per vessel: 10
- No. of vessels per concentration (replicates): 1
- No. of vessels per control (replicates): 1
- Biomass loading rate: 0.4 g fish/litre

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Tap water, dechlorinated by activated carbon and sterilized by UV lamp, was used. The water was aerated continuously over 24h.
- Total hardness: 155 mg CaCO3/L;
- Metals: Background concentration Cesium (Cs) 0.222 µg/L
- Dissolved oxygen concentration: >90% of ASV.

OTHER TEST CONDITIONS
- Adjustment of pH: No
- Photoperiod: Light∶Dark = 12 hours∶12 hours;
- Light intensity: No data

EFFECT PARAMETERS MEASURED (with observation intervals if applicable): Fish were observed and dead fish were recorded at 0, 24, 48, 72 and 96 hours after test initiation. Measurements of the pH, dissolved oxygen concentration and temperature in the test solutions were made at the beginning, before and after each renewal and at the end of the test. At the end of the test, the body length and body weight of the test fish of the control group were measured. The loading rate was also calculated with the body weight at the same time.

TEST CONCENTRATIONS
- Spacing factor for test concentrations: Not applicable, study was conducted as limit test at a nominal concentration of 120 mg/L.
- Range finding study: yes
- Test concentrations: 1.2, 12 and 120 mg/L and a blank control of test water each containing five fish
- Results used to determine the conditions for the definitive study: In the range-finding test, there were no mortalities and abnormalities observed in the fish of the control group and the treatment groups during the test

Reference substance (positive control):

no

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

> 120 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Details on results:

Analytical measurements in the limit test:
The measured concentrations of Al ranged from 4.55 to 9.78 mg/L. The time-weighted mean concentration of Al was 7.20 mg/L with variation of >20% (+/- 45.4%). Since the test substance consists of a variety of elements (Cs, Al and F), the measured concentrations of the test substance were not actually calculated by the measured concentrations of Aluminium analyzed by ICP-MS. Therefore, in order to reflect the toxicity of the test substance, the results were expressed as the nominal concentrations.

There were no mortalities and abnormalities observed in the fish of the control group and the treatment group during the test.

Validity criteria:
- No mortality was observed in the control during the test;
- Acceptable exposure conditions were maintained throughout the test;
- The dissolved oxygen concentrations in test solutions were between 72.5 -91.2 %ASV, which was greater than 60.0% of the air saturation value, throughout the test.
The test fulfilled the above requirements and was therefore considered to be valid.

Results with reference substance (positive control):

No data

Reported statistics and error estimates:

Not applicable

Validity criteria fulfilled:

yes

Conclusions:

The test results showed that the 96h LC50 for the test substance to Gobiocypris rarus was higher than 120 mg/L.

Executive summary:

The acute toxicity of Cesium fluoroaluminate to Gobiocypris rarus was determined in a semi-static test according to the OECD Testing Guideline 203 and under GLP.

During the range-finding test, a white precipitation was observed in the test solutions of the treatment groups. The test substance contains aluminum (Al) element, so the precipitation could result from the formation of low soluble salts, i.e., the reaction product between aluminum and anions (OH-) present in the test water. Thus, a 24h semi-static limit test was performed to maintain the concentration of the test substance as far as possible. Based on the results of the range-finding test, a nominal concentration of 120 mg/L and a blank control were used to perform the limit test. The treatment group and control group had one replicate, each containing 10 fish and the test duration was 96h.

There were no mortalities and abnormalities observed in treatment group during the test period. No mortality occurred in the control during the test and the dissolved oxygen concentration was greater than 60.0% of the air saturation value (ASV) throughout the test. Hence, the test was considered to be valid.

During the test, the measured concentration of aluminum (Al) analysed by ICP-MS, varied greater than 20% during the test. Since the test substance consists of a variety of elements (Cs, Al and F), the measured concentrations of the test substance were not actually calculated by the measured concentrations of Aluminium analyzed by ICP-MS. Therefore, in order to reflect the toxicity of the test substance, the results were expressed as the nominal concentrations.

The 96h LC50 for the test substance to Gobiocypris rarus was higher than 120 mg/L (the time-weighted mean concentration of Al was 7.20 mg/L) under tested conditions.

Description of key information

In a GLP- and guideline-conform semi-static limit test of cesium fluoroaluminate according to OECD 203, the 96h-LC50 for freshwater fish Gobiocypris rarus was estimated with > 120 mg cesium fluoroaluminate /L (measured, TWA) (Jing, 2013). Thus, cesium fluoroaluminate seems to have a low potential for toxicity to freshwater fish.