Chromate(2-), [2-[(4,5-dihydro-3-methyl-5-oxo-1-phenyl-1H-pyrazol-4-yl)azo]benzoato(2-)][2-[(4,5-dihydro-3-methyl-5-oxo-1-phenyl-1H-pyrazol-4-yl)azo]-5-sulfobenzoato(3-)]-, lithium sodium

Short-term toxicity to aquatic invertebrates

Administrative data

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

30 Nov - 02 Dec 1999

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2000

Report date:

2000

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Sodium bis[2-[(4,5-dihydro-3-methyl-5-oxo-1-phenyl-1H-pyrazol-4-yl)azo]benzoato(2-)]chromate(1-)

EC Number:

255-527-0

EC Name:

Sodium bis[2-[(4,5-dihydro-3-methyl-5-oxo-1-phenyl-1H-pyrazol-4-yl)azo]benzoato(2-)]chromate(1-)

Cas Number:

41741-86-0

Molecular formula:

C34H24CrN8O6.Na

IUPAC Name:

Sodium;chromium(3+);2-[(3-methyl-5-oxido-1-phenylpyrazol-4-yl)diazenyl]benzoate

Test material form:

solid: particulate/powder

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

- Concentrations: control, 0.39, 6.25 and 100 mg/L
- Sampling method: directly taken from test vessel at 0 and 48 h

Test solutions

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: stirring at 20°C for 20 h in M4 medium, 100 mg/L final concentration of eluate
- Eluate: diluted further
- Evidence of undissolved material (e.g. precipitate, surface film, etc.): yes, removed by centrifugation for 20 min

Test organisms

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Age of parental stock (mean and range, SD): 2 - 4 wk
- Feeding during test: none
- Age at study initiation: 2- 24 h

ACCLIMATION
- Acclimation period: no

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Test conditions

Hardness:

2.36 mmol/L

Test temperature:

20.4 - 20.8°C

pH:

8.0 - 8.2

Dissolved oxygen:

8.4 - 8.8 mg/L

Conductivity:

593 µS/cm

Nominal and measured concentrations:

Nominal: 0.39, 0.78, 1.56, 3.13, 6.25, 12.5, 25, 50, 100 mg/L
Measured: maximum 13% recovery in all measured concentrations

Details on test conditions:

TEST SYSTEM
- Test vessel: test tubes
- Material, size, headspace, fill volume: glass, 20 mL, flat bottom
- Aeration: no
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 4
- Biomass loading rate: 0.5 animals/mL


OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: 16 h light : 8 h dark
- Light intensity: 2 - 7 µE/(m² x s)

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : mobility at 0, 24 and 48 h

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Results and discussion

Effect concentrations

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

2.56 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: 95% CI: 1.88 - 3.51 mg/L

Details on results:

Mortality of control: 5%

Results with reference substance (positive control):

24-h EC50: 1.19 mg/L (normal sensitivity response)

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The 48-h EC50 to Daphnia magna was determined at 2.56 mg/L (mean meaured). Due to the low recovery (max. 13%) of the test item, no nominal concentration value was useful.