Dipotassium tetraoxomolybdate

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:

dec 1991 - march 1992

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Study was well performed but no measured data were available.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1994

Report date:

1994

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Version / remarks:

part 1

Test guideline 2

Qualifier:

according to guideline

Guideline:

other: EEC directive 67/548 annex V, c2 as published in 84/449/EEC

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

Diammonium dimolybdate

EC Number:

248-517-2

EC Name:

Diammonium dimolybdate

Cas Number:

27546-07-2

IUPAC Name:

Diammonium dimolybdate

Constituent 2

Reference substance name:

not listed248-517-2

IUPAC Name:

not listed248-517-2

Details on test material:

- white powder
- purity: 56,20 % molybdenum
- storage: in darkness at room temperature
- method of preparation: direct dispersion in water
- stability of test concentrations: not applicable

Sampling and analysis

Analytical monitoring:

not specified

Test solutions

Vehicle:

no

Test organisms

Test organisms (species):

Daphnia magna

Details on test organisms:

- 1st instar
- culture: at 20 +/- 2 degrees Celsius in glass vessels containing 2L of dechlorinated and aged tap water. Cultures were fed daily with a mixture of fry fish food and a suspension of mixed algae. Culture conditions ensure that reproduction is by parthogenesis
- selection: gravid adults were isolated 24h prior to initiation of the test. young daphnids produced overnight were used for testing.

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Test conditions

Hardness:

150-200 mg/mL

Test temperature:

21°C

pH:

7,1

Nominal and measured concentrations:

10, 18, 32, 56, 100, 180, 320, 560 and 1000 mg/L
in duplicate

Details on test conditions:

- test vessels: glass jars each containing 200 mL test solution
- experimental design: 20 animals per test concentration
- method of initiation: daphnia were placed in the test solutions after addition of the test substance
- loading: 20ml test solution per organism
- photoperiod: 16h light:8h dark
- aeration: none
-temp: 21 degrees Celsius
- medium renewal: none
- criterion of effect: daphnia were considered to be immobilised if they were unable to swim for approx 15 seconds after gentle agitation

Results and discussion

Effect concentrations

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

79 mg/L

Nominal / measured:

nominal

Conc. based on:

element

Basis for effect:

mortality

Details on results:

results for molybdate-salt: 140 mg/L

Reported statistics and error estimates:

Analysis according to Thompson and Weil (1952). Biometrics 8, 51-54.

Applicant's summary and conclusion

Validity criteria fulfilled:

not specified

Conclusions:

This study is well performed and documentd. The measured data are not included but standard guidelines were followed. The outcome of this study (i.e., the reported LC50) can be considered for the hazard assessment (classification ) of molybdenum compounds.