Reaction mass of Di-μ-thio-[{bis(2-ethylhexyl)carbamato-S,S’}oxo molybdenum(V)], Di-μ-thio-[{(2-ethylhexyl)carbamato-S,S’}{(branched ditridecyl)carbamato-S,S’}oxo molybdenum(V)] and Di-μ-thio-[{bis(branched ditridecyl)carbamato-S,S’}oxo molybdenum(V)]

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:

6th January to 27 Februaru 2003

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: study was conducted in a GLP compliant laboratory according to recognised regulatory guidelines

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

GLP compliance:

yes

Details on test solutions:

Identity and concentration of auxiliary solvent for dispersal: None
PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
Due to the low aqueous solubility and complex nature of the test material for the purposes of the definitive test the test material was prepared as a Water Accommodated Fraction (WAF).
Amounts of test material (20, 36, 64 and 112 mg) were each separately weighed onto a microscope slide which was suspended below the surface of 20 litres of reconstituted water to give the 1.0, 1.8, 3.2 and 5.6 mg/lloading rates respectively. Further amounts of test material (25, 45, 80, 140 and 250 mg) were each separately weighed onto a microscope slide which was suspended below the surface of 2.5 litres of reconstituted water to give the 10, 18, 32, 56 and 100 mg/lloading rates respectively. The test material was weighed onto microscope slides to ensure accuracy of weighing due to the small amounts used and the highly viscous nature of the test material. After addition ofthe test material, the reconstituted water was stirred for 23 hours by magnetic stirrer such that a vortex depth of approximately 25% of the overall height of the water column was achieved. The stirring was stopped after 23 hours and the mixtures allowed to stand for 1 hour prior to removing the aqueous phase or WAF by mid-depth siphoning to give the 1.0, 1.8,3.2,5.6, 10, 18,32,56 and 100 mg/lloading rate WAFs.
Information provided by the Sponsor indicated that the test material may undergo photo-oxidation when exposed to natural or artificial daylight. Therefore, all media preparation was conducted under laboratory safety lighting (low intensity non-actinic light source used to prevent photodegradation of light sensitive materials). The remainder of media preparation (stirring and standing) and the exposure phase ofthe test were performed shielded from the light.

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name:
- Strain: N/a
- Source:in-house laboratory cultures
- Age at study initiation (mean and range, SD): 1st instar
- Weight at study initiation (mean and range, SD):
- Length at study initiation (length definition, mean, range and SD):
- Valve height at study initiation, for shell deposition study (mean and range, SD):
- Peripheral shell growth removed prior to test initiation:
- Method of breeding: parthenogenesis
- Feeding during test Yes
- Food type: suspension of algae (Chlorella sp.)
- Amount: Not specified
- Frequency: daily

ACCLIMATION
- Acclimation period: N/a
- Acclimation conditions (same as test or not): same as test
- Type and amount of food: suspension of algae (Chlorella sp.)
- Feeding frequency: Daily
- Health during acclimation (any mortality observed): No

Test type:

static

Water media type:

freshwater

Hardness:

250 mg/L as CaCO3

Test temperature:

21C

pH:

7.9 - 8.0

Dissolved oxygen:

8.0 - 8.2 mgO2/L (90 - 92% ASV)

Salinity:

N/a

Nominal and measured concentrations:

NOMINAL CONCENTRATIONS: 1.0, 1.8, 3.2, 5.6, 10, 18, 32, 56 and 100 mg/L
Measured concentrations: The test material was not detected at the initial time point and after 48 hours in the test medium in light and dark conditions.

Key result

Duration:

48 h

Dose descriptor:

EL50

Effect conc.:

15 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Remarks on result:

other: 95% CL

Key result

Duration:

48 h

Dose descriptor:

NOELR

Effect conc.:

5.6 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Validity criteria fulfilled:

yes

Conclusions:

The acute toxicity of the test material to the freshwater invertebrate Daphnia magna has been investigated and gave a 48-Hour EL·50 value of 15 mg/l loading rate WAF with 95% confidence limits of 13 - 18 mg/l loading rate WAF. The No Observed Effect Loading rate at 48 hours was 5.6 mg/ lloading rate WAF.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

15 mg/L

Additional information

The EL50 value refers to nominal loading level resulting from water accomodated fraction (WAF). Water solubility of the substance is < 0.1 mg/l.