Ruthenium trichloride hydrate

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

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

not specified

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Deviations:

not specified

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

Analytical verification carried out at 0 and 48h. Concentration of stock solution determined after 0h.
In Main test 2, dissolved and undissolved ruthenium was detected by acidification of the test samples prior to analytical determination. Analytical results were expressed as test item concentrations based on a ruthenium content of 36.86%.

Vehicle:

no

Details on test solutions:

Stock solution preparation: 1g/l of test item equilibrated in completely desalted water. Six test concentrations and a control were included.

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Strain/clone: Daphnia magna Straus, clone 5
- Source: Bayer AG Leverkusen Germany bred in house via standard operating procedure
- Age of parental stock (mean and range, SD): Every 4 weeks (approx) offspring isolated. Females separated from offspring 24 hrs before start of test. Offspring produced overnight transferred into test water and are used for test
- Feeding during test: None

ACCLIMATION
- Acclimation conditions (same as test or not): Animals maintained in M4 medium and fed Desmodesmus subspicatus, under culture conditions that ensure parthenogenesis. At two to three day intervals exuviae are syphoned off and water changed and the offspring removed.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Hardness:

250 mg/l CaCO3 (synthetic freshwater)

Test temperature:

20.2 - 20.5 °C (mean 20.4°C)

pH:

0 h: 5.8 - 7.7 in control and 4 lowest test concentrations; 3.6 - 4.2 in 2 highest test concentrations
48h: 7.0 - 7.7 in control and 4 lowest test concentrations; 3.8 - 4.7 in 2 highest test concentrations

Dissolved oxygen:

0 h: 9.0 - 9.2 mg/L
48h: 8.0 - 8.4 mg/L

Salinity:

not applicable

Nominal and measured concentrations:

Nominal concentrations: 18, 25, 35, 50, 70, 100 mg/L
Measured concentrations used for biological evaluation: 17, 23, 32, 46, 63 and 84 mg/L

Results were based on the geometrical mean of the analytical concentrations determined after 0 and 48 hours as the measured test concentrations after 48 hours deviated by more than 20% from the freshly prepared test solutions

Details on test conditions:

TEST SYSTEM
- Test vessel: round bottom test tubes calibrated to 10 mL
- Aeration: None
- Renewal rate of test solution (frequency/flow rate): None
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 4

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: synthetic freshwater
- Ca/mg ratio: 4:1
OTHER TEST CONDITIONS
- Adjustment of pH: None. pH effects were likely at the highest test concentrations
- Photoperiod: Dark

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : Mobility assessed at 24 and 48 hours

Reference substance (positive control):

yes

Remarks:

potassium dichromate (tested as a reference item quarterly)

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

53 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

46 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

pH of the two highest test solutions was 3.6 - 4.7 therefore toxicity at these test concentrations (63 and 84 mg/L) is likely to be as a result of low pH.
After 48 hours a brown coating was observed on the Daphnia. Flocculate is therefore likely to have impacted on toxicity to the Daphnia.

Results with reference substance (positive control):

Results from September 3, 2003:
20% immobilisation at 1 mg/L
100% immoblilisation at 2 mg/L

Reported statistics and error estimates:

EC50 values determined graphically

Validity criteria fulfilled:

yes

Remarks:

Immobilisation or Daphnia in the control did not exceed 10% and dissolved oxygen was ≥60% of the air saturation value at the end of the test. As measured test concentrations deviated from nominal, results were based on mean measured concentrations.

Conclusions:

The 48h EC50 for ruthenium trichloride (hydrate) to Daphnia magna was 53 mg L-1.

Executive summary:

Enste-Diefenbach (2003) is GLP compliant study and follows OECD guideline 202 and EU method C2. The study was conducted over 48 hours under static conditions. Test concentrations were analysed and results based on mean measured concentrations. There are limitations with the study as evidence of flocculants was observed in the test solutions after 48 hours and there were likely to have been pH effects at the highest test concentrations. The toxicity observed is therefore unlikely to be solely due to toxicity of the test item. The 48h EC50 for ruthenium trichloride (hydrate) to Daphnia magna was 53mg L-1.

Description of key information

The 48h EC50 for ruthenium trichloride (hydrate) to Daphnia magna was 53 mg L-1.

Additional information

Enste-Diefenbach (2003) is GLP compliant study and follows OECD guideline 202 and EU method C2. The study was conducted over 48 hours under static conditions. Test concentrations were analysed and results based on mean measured concentrations. There are limitations with the study as evidence of flocculants was observed in the test solutions after 48 hours and there were likely to have been pH effects at the highest test concentrations. The toxicity observed is therefore unlikely to be solely due to toxicity of the test item. The 48h EC50 for ruthenium trichloride (hydrate) to Daphnia magna was 53 mg L-1.