lambda4-cerium(4+) zirconium(4+) tetraoxidandiide

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

Study period:

from 30-nov-2007 to 19-dec-2008

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method C.1 (Acute Toxicity for Fish)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

- Concentrations:
For the measurement of the concentration of cerium in this semi-static test, the following samples were taken: triplicate samples from the freshly prepared test medium (loading rate 100 mg/l) and control just before test start (Day 0) and on the last day of preparation of the test medium (Day 3); triplicate samples from the aged test medium (loading rate 100 mg/l) and control at the end of the first test medium renewal period (Day 1) and at the end of the last renewal period (Day 4)
- Sampling method: All samples were taken from the approximate center of the aquaria without mixing of the test media.
- Sample storage conditions before analysis: Immediately after sampling, the samples were acidified with 10% (v/v) nitric acid (HNO3, 65% Suprapur®, Merck) to stabilise the samples during the storage period. Then the samples were stored at room temperature in the dark.

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
- Method:
The test item is a multi-constituent substance containing different sparingly soluble components. In order to assess its toxicity, a water accommodated fraction (WAF) was prepared. The test method was based on the OECD Guidance Document on Aquatic Toxicity Testing of Difficult Substances and Mixtures.
The WAF with the loading rate of 100 mg/L was prepared before the start of the test and before each test medium renewal as follows:
A dispersion was prepared in two batches by mixing 900 mg of the test item (dosing range: 900.1-900.9 mg) into 9 liters of test water using ultrasonic treatment for 15 minutes and intense stirring. The dispersion was stirred on a magnetic stirrer for 6 days at room temperature in the dark to dissolve a maximum amount of the different sparingly soluble components of the test item in the dispersion. Then, stirring was stopped and after another day the undissolved test item had completely settled down on the bottom of the stirring vessel. The contact time of the test item and test water for equilibration (i.e., stirring time and deposition period) was 7 days. The clear equilibrated supernatant was carefully separated from the non-dissolved test item and was used as test medium.
The maximum contact time of 7 days was chosen according to the results of a pre-test (non-GLP) in which the concentration of dissolved cerium was below the limit of quantification during the stirring period of 7 days. The deposition time of one day was necessary to allow a maximum amount of the undissolved test item to deposit.
- Controls: blank (test water without addition of the test item)
- Evidence of undissolved material (e.g. precipitate, surface film, etc): yes, on the bottom of the stirring vessel, but not in the final test solution.

Test organisms (species):

Oncorhynchus mykiss (previous name: Salmo gairdneri)

Details on test organisms:

TEST ORGANISM
- Common name: Rainbow trout
- Source: P. Hohler, trout breeding station Zeiningen (Switzerland)
- Age at study initiation (mean and range, SD): no data
- Length at study initiation (mean +/- SD): 5.0 +/- 0.34 cm
- Weight at study initiation (mean +/- SD): 1.1 +/- 0.24 g
- Feeding during test : no

ACCLIMATION
- Acclimation period: the fish were held in the laboratory for more than twelve days without any medication. Prior to the test start, they were acclimated for 1 week to the test water and temperature.
- Type and amount of food: commercial fish diet (Hokovit 502)
- Feeding frequency: at least 3 times per week until one day before the start of the test.
- Health during acclimation (any mortality observed): During holding and acclimatisation no fish died in the test fish batch and all fish were healthy.

Test type:

semi-static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

96 h

Hardness:

170 mg/L as CaCO3

Test temperature:

13°C

pH:

8.2-8.4

Dissolved oxygen:

Between 9.5 and 9.9 mg/L

Salinity:

not applicable

Nominal and measured concentrations:

Nominal loading rate: 100 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel:
- Type (delete if not applicable): open
- Material, size, headspace, fill volume: glass aquarium with about 15 L of test medium
- Aeration: The test water was aerated prior to the preparation of the test media until oxygen saturation was reached. During the test period, the test medium and the control were slightly aerated.
- Type of flow-through (e.g. peristaltic or proportional diluter): none (semi-static test)
- Renewal rate of test solution (frequency/flow rate): every day
- No. of organisms per vessel: 7
- No. of vessels per concentration (replicates): 1
- No. of vessels per control (replicates): 1
- Biomass loading rate: 0.5 g fish wet weight / L

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: local tap water (non chlorinated well water of drinking quality) reduced for total hardness by ion exchange
- Total organic carbon: no data
- Particulate matter: no data
- Metals: Cd < 0.5, As < 3, lead < 3, mercury < 1, selenium < 3, copper < 4 µg/L
- Pesticides: lindane, heptachlor, malathion, DDT total, dieldrin < 0.05 µg/L
- Chlorine: no data
- Alkalinity: no data
- Ca/mg ratio: no data
- Conductivity: no data
- Bacteriological parameters: at the time of sampling, the tested parameters met the requirement for drinking water.
- Culture medium different from test medium: no data
- Intervals of water quality measurement: The water temperature, pH values and oxygen concentrations were measured at the single test concentration and in the control at the start of the test and once every day during the test in the freshly prepared and old test medium. At the same dates the appearance of the test medium was recorded. The total hardness of the water used in the test was measured at the start of the test in
the control.

OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: 16-hour light and 8-hour darkness with a 30-minute transition period
- Light intensity: 70- 500 lux

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : The test fish were observed after approximately 3, 24, 48, 72 and 96 hours test duration for mortality and visible abnormalities.
The NOELR and the LL0 were determined directly from the raw data. The LOELR, the LL100 and the LL50 at the observation times could not be quantified due to the absence of a toxic effect of the test item at the tested loading rate.

TEST CONCENTRATIONS
- Spacing factor for test concentrations: not applicable (limit test)
- Range finding study: yes
- Test concentrations of the range finding study: no data
- Results used to determine the conditions for the definitive study: no mortality at the undiluted loading rate.

Reference substance (positive control):

no

Key result

Duration:

96 h

Dose descriptor:

LL50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Duration:

96 h

Dose descriptor:

NOELR

Effect conc.:

>= 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Details on results:

BIOLOGICAL RESULTS
- Behavioural abnormalities: none
- Observations on body length and weight: none
- Other biological observations: none
- Mortality of control: none
- Other adverse effects in control: none
- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: none
- Effect concentrations exceeding solubility of substance in test medium: none

APPEARANCE OF THE TEST MEDIUM
No remarkable observations were made concerning the appearance of the test medium. It was a clear solution throughout the test medium renewal periods.

ANALYTICAL MONITORING
In the analysed test medium samples from the start of the test medium renewal periods the measured cerium concentration ranged between 29 and 47 µg/L. During the test medium renewal period of 24 hours a decrease of the cerium concentration in the test medium was determined. At the end of the test medium renewal periods, the measured concentration was in the range of 7.0 to 15 µg/L cerium. The mean measured cerium concentration during the renewal periods of 24 hours was calculated as the geometric mean between the measurements at the start and the end of the renewal periods. From these mean concentrations, the total mean cerium concentration during the test period of 96 hours was calculated as arithmetic mean. The total mean measured concentration of cerium was 19 µg/L, corresponding to 40 µg/L test item.

Results with reference substance (positive control):

not tested

Reported statistics and error estimates:

not necessary as no mortality was observed

Sublethal observations / clinical signs:

Mortality and visible abnormalities observed in the test fish :

Loading rate (mg/L)	Mean measured test item Concentration (µg/L)	Number of abnormal and dead fish / number of dead fish
		Observation time
		3 hours	24 hours	48 hours	72 hours	96 hours
Control	-----	0 / 0	0 / 0	0 / 0	0 / 0	0 / 0
100	40	0 / 0	0 / 0	0 / 0	0 / 0	0 / 0
LL50		> 100 mg/L based on loading rate > 40 µg/L based on mean measured test item concentration

 

Validity criteria fulfilled:

yes

Conclusions:

The test item had no acute toxic effects on rainbow trout up to the highest concentration which could be tested at a loading rate of 100 mg/L.

Executive summary:

The acute toxicity of the reaction mass of cerium dioxide and zirconium dioxide to rainbow trout (Oncorhynchus mykiss) was determined in a 96-hour semi-static test with a daily test medium renewal according to the EU Commission Directive 92/69/EEC, Part C.1 (1992), and the OECD Guideline for Testing of Chemicals No. 203 (1992).

Rainbow trouts were exposed to control and test chemical at a loading rate of 100 mg/L. The test fish were observed after approximately 3, 24, 48, 72 and 96 hours test duration for mortality and visible abnormalities. No mortality or visible abnormalities were determined in the control and at the loading rate of 100 mg/L during the 96h-period. Therefore, the 96-hour NOELR and the 96-hour LL0 of the test item to rainbow trout were determined to be >= 100 mg/L. The 96-hour LOELR, the 96-hour LL50 and 96-hour LL100 were > 100 mg/L.

Reference 2

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

from 30 oct 2000 to 29 nov 2000

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Remarks:

The study was conducted according to the OECD internationally recognised guideline, but the GLP are not stated, and no analytics were performed.

Reason / purpose for cross-reference:

reference to same study

Qualifier:

according to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

Deviations:

no

GLP compliance:

no

Analytical monitoring:

no

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: The substance practically insoluble in water was introduced in the test medium by weighed adequate quantity and was dispersed by stirring. The dissolution was continued during a period of 168 hours to be sure that the equilibrium was reached and "soluble fraction" stable during the test. After correction of evaporation by addition of deionised water, stirring was stopped and the different suspensions were decanted for a resting period of 4 hours.
- Controls: yes, test water without test item
- Evidence of undissolved material (e.g. precipitate, surface film, etc): no

Test organisms (species):

Danio rerio (previous name: Brachydanio rerio)

Details on test organisms:

TEST ORGANISM
- Common name: Zebra fish
- Source: Pisciculture Exotique - Dourdan, 91, France
- size/weight: 30.4 mm, 0.3 g;
- Method of breeding: The fish were bred in reconstituted water (ISO 7346) with continual aeration and filtering device
- Food: TetraMin Tetra during breeding (no feeding during the test);

ACCLIMATION
- Acclimation period: 2 weeks
- Acclimation conditions: same as test
- Health during acclimatation: mortality less than 1% within the adaptation period.

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

96 h

Hardness:

250 mg/L +/- 25 mg/L as CaCO3.

Test temperature:

24°C +/- 1°C

pH:

7.17-7.87

Dissolved oxygen:

4.5-8.2 mg/L

Salinity:

not applicable

Nominal and measured concentrations:

100 mg/l

Details on test conditions:

TEST SYSTEM
- Test vessel:
- Type : 5-L glass beakers
- Fill volume: 4 L of reconstituted water
- Aeration: none during the test, but dilution water was previously saturated with oxygen before the start of the test
- No. of organisms per vessel: 10
- No. of vessels per concentration (replicates): 1
- No. of vessels per control (replicates): 1
- Biomass loading rate: 0.76 g/L

WATER PARAMETERS
- Source: reconstituted water-ISO 7346
- Conductivity: < 5 µs/cm
- Intervals of water quality measurement : pH and dissolved oxygen were measured after 0, 24, 48, 72 and 96 h of exposure
- No further data

OTHER TEST CONDITIONS
- Photoperiod: about 12 h light daily
- Light intensity: natural diffused lighting

EFFECT PARAMETERS MEASURED : Immobility and absence of respiration motion observed after 3, 24, 48, 72 and 96 h of exposure

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Duration:

96 h

Dose descriptor:

LL50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Duration:

96 h

Dose descriptor:

NOELR

Effect conc.:

>= 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Details on results:

No mortality was observed during the test, either in control or test groups.
No abnormal response of the fish was observed during the test period.

Results with reference substance (positive control):

- Results with reference substance valid? yes
- Mortality: no data
- 24h LC50: 226 mg/L (K2Cr2O7). This calculated value was between the interval (200-400 mg/L) formerly defined by the method, and was used to validate the selected fish batch.

Validity criteria fulfilled:

yes

Conclusions:

Using a limit test at 100 mg/L, cerium dioxide had no acute toxic effect on the fish Danio rerio.

Executive summary:

The 96hr-acute toxicity of cerium dioxide to Brachydanio rerio was studied under static conditions according to OECD Guideline 203. Brachydanio rerio were exposed to control and test chemical at nominal concentration of 100 mg /L. Mortality/immobilisation were observed daily. No mortality was observed during the test, neither in the control nor in the group exposed to the test item. The 96 hour LL50 and NOELR were thus > 100 mg/L.

Reference 3

Endpoint:

short-term toxicity to fish

Type of information:

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

Adequacy of study:

supporting study

Justification for type of information:

Read across from studies performed with cerium dioxide and zirconium dioxide. The read across justification document is attached in IUCLID Section 13.

Reason / purpose for cross-reference:

read-across source

Reason / purpose for cross-reference:

read-across source

Duration:

96 h

Dose descriptor:

LL50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: Based on the results from studies conducted with cerium dioxide and zirconium dioxide, it can be concluded that no adverse effects are expected for the reaction mass of cerium dioxide and zirconium dioxide either.

Reference 4

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

from 30 oct 2000 to 29 nov 2000

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Remarks:

The study was conducted according to the OECD internationally recognised guideline, but the GLP are not stated, and no analytics were performed.

Reason / purpose for cross-reference:

reference to same study

Qualifier:

according to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

Deviations:

no

GLP compliance:

no

Analytical monitoring:

no

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: The substance, practically insoluble in water, was introduced in the test medium by weighed adequate quantity and was dispersed by stirring. The dissolution was continued during a period of 168 hours to be sure that the equilibrium was reached and "soluble fraction" stable during the test. After correction of evaporation by addition of deionised water, stirring was stopped and the different suspensions were decanted for a resting period of 4 hours.
- Controls: yes, test water without test item
- Evidence of undissolved material (e.g. precipitate, surface film, etc): no

Test organisms (species):

Danio rerio (previous name: Brachydanio rerio)

Details on test organisms:

TEST ORGANISM
- Common name: Zebra fish
- Source: Pisciculture Exotique - Dourdan, 91, France
- Size/weight: 30.4 mm, 0.3 g
- Method of breeding: The fish were bred in reconstituted water (ISO 7346) with continuous aeration and filtering device
- Food: TetraMin Tetra during breeding (no feeding during the test)

ACCLIMATION
- Acclimation period: 2 weeks
- Acclimation conditions: same as test
- Health during acclimation: mortality less than 1% within the adaptation period

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

96 h

Post exposure observation period:

none

Hardness:

250 mg/L +/- 25 mg/L as CaCO3.

Test temperature:

24°C +/- 1°C

pH:

7.17-7.83

Dissolved oxygen:

4.5-8.2 mg/L

Salinity:

not applicable

Nominal and measured concentrations:

100 mg/L (nominal loading rate)

Details on test conditions:

TEST SYSTEM
- Test vessel:
- Type: 5-L glass beakers
- Fill volume: 4 L of reconstituted water
- Aeration: none during the test, but dilution water was previously saturated with oxygen before the start of the test
- No. of organisms per vessel: 10
- No. of vessels per concentration (replicates): 1
- No. of vessels per control (replicates): 1
- Biomass loading rate: 0.76 g/L

WATER PARAMETERS
- Source: reconstituted water-ISO 7346
- Conductivity: < 5 µs/cm
- Intervals of water quality measurement: pH and dissolved oxygen were measured after 0, 24, 48, 72 and 96 h of exposure
- No further data

OTHER TEST CONDITIONS
- Photoperiod: about 12 h light daily
- Light intensity: natural diffused lighting

EFFECT PARAMETERS MEASURED : Immobility and absence of respiration motion observed after 3, 24, 48, 72 and 96 h of exposure

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Duration:

96 h

Dose descriptor:

LL50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Details on results:

No mortality was observed during the test, either in control or test groups.
No abnormal response of the fish was observed during the test period.

Results with reference substance (positive control):

- Results with reference substance valid? yes
- Mortality: no data
- 24h LC50: 226 mg/L (K2Cr2O7). This calculated value was between the interval (200-400 mg/L) formerly defined by the method, and was used to validate the selected fish batch.

Validity criteria fulfilled:

yes

Conclusions:

Using a limit test at 100 mg/L, zirconium dioxide had no acute toxic effect on the fish Danio rerio.

Executive summary:

The 96-h acute toxicity of zirconium dioxide to Brachydanio rerio was studied under static conditions, according to OECD Guideline 203. Fish were exposed to control and test chemical at a nominal concentration of 100 mg/L. Mortality/immobilisation were observed daily. No mortality was observed during the test, neither in the control nor in the group exposed to the test item. The 96-h LL50 was thus > 100 mg/L.

Description of key information

The 96-hour LL50 (Oncorhynchus mykiss) of the reaction mass of cerium dioxide and zirconium dioxide is > 100 mg/L, revealing it is not harmful for the fish species tested. The test was carried out with a representative nanoform of the test substance, however the same conclusion is expected for any potential bulk forms of the reaction mass of cerium dioxide and zirconium dioxide, should these be placed on the market. This is supported by data available for bulk forms of the main constituents of the reaction mass, cerium dioxide and zirconium dioxide.

Additional information

A GLP-compliant study, scored as Klimisch 1 and flagged as a key study, is available on the reaction mass (test item = representative nanoform),and yielded a 96h-LL50 > 100 mg/L, revealing that the reaction mass is not harmful to Oncorhynchus mykiss (Bätscher, 2008a).

One experimental study, scored as Klimisch 2 (Bazzon, 2000), is also available on cerium dioxide and zirconium dioxide (bulk forms). This study yielded consistent results for Brachydanio rerio, i.e. 96h-LL50 > 100 mg/L. These studies are considered as supporting information.