Digadolinium trioxide

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:

6 November 2000 - 29 November 2000

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

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

Qualifier:

according to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

Deviations:

no

GLP compliance:

not specified

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 in each test beaker 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.

Test organisms (species):

Danio rerio (previous name: Brachydanio rerio)

Details on test organisms:

TEST ORGANISM
- Common name: Zebrafish
- Source: Pisciculture Exotique - Dourdan, 91, France
- Mean size/weight: 30.4 mm, 0.3 g

ACCLIMATION
- Acclimation period: 2 weeks
- Acclimation conditions: same as test
- The fish were held in reconstituted water (ISO 7346) with continual aeration and filtering device.
- Food: TetraMin Tetra (or similar) during holding (no feeding during the test).
- Lighting: Natural diffused lighting.
- 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:

Control: 7.17-7.80
100 mg/L: 7.29-7.85

Dissolved oxygen:

Control: 4.5-8.2 mg/L
100 mg/L: 5.7-8.2 mg/L

Salinity:

not applicable

Nominal and measured concentrations:

Nominal: blank and 100 mg/L
Gd concentrations were not measured during the test.

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): 294.0 mg/L CaCl2.2H2O, 123.3 mg/L MgSO4.7H2O, 63.0 mg/L NaHCO3, 5.5 mg/L KCl
- Conductivity of deionised water used: < 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

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)

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
- 24-h LC50: 226 mg/L (K2Cr2O7). This value was between the interval (200-400 mg/L) formely defined by the method (24 h static conditions), and was used to validate the selected fish batch.

Reported statistics and error estimates:

No statistics performed (no mortality observed).

Validity criteria fulfilled:

yes

Conclusions:

The 96-h acute toxicity of gadolinium oxide to Brachydanio rerio was studied under static conditions according to OECD Guideline 203. Zebrafish 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

Bazzon (2000) investigated the acute toxicity of gadolinium oxide to zebrafish (Brachydanio rerio) according to OECD guideline 203. After 96 h, no mortality or immobilisation was observed in the blank or the 100 mg/L limit test concentration. The LL50 was therefore > 100 mg/L. No analytics were performed during this study, therefore the reliability was scored Klimisch 2 (reliable with restrictions).