6H-Furo[2',3':4,5]oxazolo[3,2-a]pyrimidin-6-one, 2,3,3a,9a-tetrahydro-3-hydroxy-2-(hydroxymethyl)-7-methyl-, (2S,3S,3aR,9aS)-

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:

01 July - 03 July 2008

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Deviations:

no

Qualifier:

according to guideline

Guideline:

ISO 6341 (Water quality - Determination of the Inhibition of the Mobility of Daphnia magna Straus (Cladocera, Crustacea))

Deviations:

no

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

- Concentrations: all test concentrations

- Sampling method:
Frequency at t=0 h and t=48 h
Volume 3 ml from the approximate centre of the test vessels
At the end of the exposure period, the replicates were pooled at each concentration before sampling.

- Sample storage conditions before analysis: in a freezer until analysis

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
Preparation of test solutions started with the highest test solution of 100 mg/l. No special treatment was necessary to completely dissolve the test substance in the test medium. The lower test concentrations were prepared by subsequent dilutions of the highest concentration in test medium. The final test solutions were all clear and colourless.

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: Daphnia magna (Crustacea, Cladocera) (Straus, 1820)
- Source: In-house laboratory culture with a known history.
- Age at study initiation (mean and range, SD): For the test selection of young daphnids with an age of < 24 hours, from parental daphnids of more than two weeks old.
- Method of breeding: With newborn daphnids, i.e. less than 3 days old, by placing about 250 of them into 5 litres of medium in an all-glass culture vessel.
- Feeding during test: noo feeding

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

48 h

Post exposure observation period:

No post exposure observations.

Hardness:

180 mg/l

Test temperature:

19.5 - 20.0°C

pH:

6.0-8.5

Dissolved oxygen:

>=3 mg/l at the end of the test

Nominal and measured concentrations:

See the table "Concentrations of the test substance in test medium" below

Details on test conditions:

TEST SYSTEM
- Test vessel:
- Type: open
- Material, size, headspace, fill volume: 100 ml, all-glass
- Aeration: No aeration of the test solutions.
- No. of organisms per vessel: 5 per vessel containing 80 ml of test solution
- No. of vessels per concentration (replicates): 4 for the highest concentration; 2 each for the lower concentration
- No. of vessels per control (replicates): 2

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Adjusted ISO medium
- Culture medium different from test medium: yes, M7 medium


OTHER TEST CONDITIONS
- Adjustment of pH: 7.7 ± 0.3.
- Photoperiod: 16 hours photoperiod daily


EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
Immobility (including mortality): At 24 hours and at 48 hours.
pH and dissolved oxygen: At the beginning and at the end of the test, for all concentrations and the control.
Temperature of medium: Continuously in a temperature control vessel, beginning at the start of the test.


TEST CONCENTRATIONS
- Test concentrations: 0.1, 1.0, 10 and 100 mg/l.
- Controls: Test medium without test substance or other additives.

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

loading rate

Basis for effect:

mobility

Key result

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

loading rate

Basis for effect:

mobility

Details on results:

- Behavioural abnormalities: none
- Mortality of control: none
- Other adverse effects control: none
- Abnormal responses: none
- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: none

Results with reference substance (positive control):

- Results with reference substance valid? yes
- Mortality: 5% at 0.32 mg/l after 48h, 15% at 0.56 mg/l after 48h, 100% at 1 mg/l after 48h
- EC50/LC50:
The 24h-EC50 was 0.77 mg/l with a 95% confidence interval between 0.68 and 0.91 mg/l.
The 48h-EC50 was 0.62 mg/l with a 95% confidence interval between 0.53 and 0.77 mg/l.

Concentrations of the test substance in test medium

Time of sampling [hours]	Concentration
	Nominal [mg/l]	Analysed [mg/l]	Relative to nominal [%]	Relative to initial [%]
0	0	*	n.a.
	100	102	102
48	0	*	n.a.	n.a.
	100	102	102	100

* A small response at the retention time of the test substance was observed. It was not considered to derive from the test samples since it was also observed in the analytical blanks.

- Recovery: The mean recovery of the procedural recovery samples was 99%. Because the criterion that mean recoveries should be between 70% and 110% was met, the results for the test samples were accepted.

Validity criteria fulfilled:

yes

Conclusions:

Under the conditions of the present study the test substance did not induce acute immobilisation of Daphnia magna at 100 mg/l after 48 hours of exposure (NOEC).

The 48h-EC50 exceeded 100 mg/l, the regulatory limit concentration.

Description of key information

Under the conditions of the present study the test substance did not induce acute immobilisation of Daphnia magna at 100 mg/l after 48 hours of exposure (NOEC).

The 48h-EC50 exceeded 100 mg/l, the regulatory limit concentration.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

100 mg/L