Cerium terbium magnesium undecaaluminum nonadecaoxide (hexagonal) ((Ce, Tb)MgAl11O19) and aluminium oxide (Al2O3) from calcination of Al2O3, CeO2, MgO and Tb4O7

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

29 November 2011 - 01 December 2011

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Reason / purpose for cross-reference:

reference to other study

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Deviations:

no

Qualifier:

according to guideline

Guideline:

ISO 6341 (Water quality - Determination of the Inhibition of the Mobility of Daphnia magna Straus (Cladocera, Crustacea))

Deviations:

no

Qualifier:

according to guideline

Guideline:

other: Guidance document on aquatic toxicity testing of difficult substances and mixtures, OECD series on testing and assessment number 23, December 14, 2000

Deviations:

no

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

Samples for possible analysis were taken from all test concentrations and the control:
Frequency: at t=0 h and t=48 h
Volume: 4.8 ml from the approximate centre of the test vessels
Storage: Samples were stored in a freezer until analysis

In addition, the filter used for the preparation of the highest test concentration was retained for possible analysis of the residue. Additionally, reserve samples of 4.8 ml were taken for possible analysis. If not used, these samples were stored in a freezer for a maximum of three months after delivery of the draft report, pending on the decision of the sponsor for additional analysis.

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: Preparation of test solutions started with aquatic mixtures prepared individually at loading rates of 1.0, 10 and 100 mg/l. The mixtures were treated with ultrasonic waves for 10 minutes and then magnetically stirred for two days. The resulting dispersions were filtered through a 0.45 μm membrane filter (Whatman; RC55) to remove the remaining undissolved material. The resulting filtrates were all clear and colourless.

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: Daphnia magna
- Source: In-house laboratory culture with a known history
- Age at study initiation (mean and range, SD): young daphnids with an age of < 24 hours, from parental daphnids of more than two weeks old
- Method of breeding: With newborn daphnids, i.e. less than 3 days old, by placing about 250 of them into 5 litres of medium in an all-glass culture vessel.
- Feeding during test: none
- Feeding during breeding: daily, a suspension of fresh water algae
- Medium breeding: M7

Test type:

static

Water media type:

freshwater

Total exposure duration:

48 h

Post exposure observation period:

none

Hardness:

180 mg/l expressed as CaCO3

Test temperature:

20.4 - 21.5 ºC

pH:

7.7 -8.1

Dissolved oxygen:

8.8-9.5

Salinity:

Not applicable

Nominal and measured concentrations:

Analyses were based on Aluminium (Al), Cerium (Ce) and Terbium (Tb). Note that analysis of Magnesium (Mg) was not considered as Magnesium is present in a relative high concentration in the test medium.
No detectable concentrations of Al were present during the 48-hour exposure period. Concentrations of Ce and Tb were detectable during the test period with measured concentration of 2.7 μg Ce/l and 13 μg Tb/l at the start that slightly decreased to 2.1 μg Ce/l and 9.4 μg Tb/l, after 48 hours of exposure (mean measured concentration were 2.4 μg Ce/l and 11.0 µg Tb/L).

Details on test conditions:

TEST SYSTEM
- Type (delete if not applicable): open
- Material, size, headspace, fill volume: all-glass, 100 ml, each vessel contains 80 ml test solution
- Aeration: no
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 4 for highest test concentration, 2 for both lower concentrations
- No. of vessels per control (replicates): 4

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: adjusted ISO medium

OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: 16 hours daily
- Light intensity: no information

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : immobility at 24 and 48 hrs

TEST CONCENTRATIONS: combined limit/range-finding test
- Spacing factor for test concentrations: 10
- Test concentrations: filtered solutions prepared at loading rates of 1.0, 10 and 100 mg/L

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Key result

Remarks on result:

other: The 48h-EC50 exceeds the maximum soluble concentration of test substance in test medium.

Details on results:

The EC50 exceeds the maximum soluble concentration of test substance in test medium.
No (significant) immobilisation was observed at any of the test concentrations during the test period. A maximum of 5% immobility was reported at the highest concentration at 48hrs and not considered significant.

Results with reference substance (positive control):

The 48h-EC50 was 0.28 mg/l with a 95% confidence interval between 0.26 and 0.32 mg/l.
The actual responses in this reference test with K2Cr2O7 were just outside (below) the ranges of the expected historical responses at the different concentrations, i.e. a 48h-EC50 between 0.3 and 1.0 mg/l. Hence, the sensitivity of this batch of D. magna was slightly higher when compared to the
historical data collected at NOTOX.

Validity criteria fulfilled:

yes

Conclusions:

The substance did not induce significant acute immobilisation of Daphnia magna exposed to a 0.45 μm filtered solution prepared at a loading rate of 100 mg/l after 48 hours of exposure. The 48h-EC50 exceeded the concentration present in a filtered solution prepared at a loading rate of 100 mg/l, which was considered the maximum soluble concentration in test medium. Due to the very low solubility in test medium, concentrations toxic for Daphnia magna could not be reached.

Description of key information

CAT was tested in a static acute toxicity study with Daphnia magna (OECD 202). The substance did not induce significant acute immobilisation of Daphnia magna exposed to a 0.45 μm filtered solution prepared at a loading rate of 100 mg/l after 48 hours of exposure.

Additional information

CAT was tested in a static acute toxicity study with Daphnia magna (OECD 202). The substance did not induce acute immobilisation of Daphnia magna exposed to a 0.45 μm filtered solution prepared at a loading rate of 100 mg/l after 48 hours of exposure. The 48h-EC50 exceeded the concentration present in a 0.45 μm filtered solution prepared at a loading rate of 100 mg/l, which was considered the maximum soluble concentration in test medium.