RM23

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:

May 17, 2000 - May 19, 2000

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)

Version / remarks:

April 4, 1984

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Version / remarks:

1992

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

no

Remarks:

The water solubility of the test material is under the limit of quantification and thus no analysis was performed.

Details on sampling:

The analysis of the saturated aqueous solution revealed that the solubility of the test item in water is < 0.0000975 g/L.
The limit of detection was given to be about 0.0000975 g/L.
The limit of quantification was described to be about 0.000325 g/L.
The test material concentrations in the study were under the limit of quantification and no analysis was performed.

Vehicle:

yes

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: The test medium (reconstituted water and test material) was freshly prepared. Therefore, the calibrated flask with test material and vehicle, reconstituted water, was treated in an ultrasonic device for 1 hour. Subsequently the preparation was aerated, and stirred with a magnetic stirrer for further 23 hours. After 24 hours the formulation was given through a nutsch filter (pore size > 10 - <16 μm). The filtrate was used for the study.
- Chemical name of vehicle: reconstituted water

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: water flea
- Strain/clone: Daphnia magna (Straus)
- Source: Merck KGaA, Darmstadt, Institute of Toxicology
- Age of parental stock: not older than 24 hours
- Feeding during test: no

METHOD FOR PREPARATION AND COLLECTION OF EARLY INSTARS OR OTHER LIFE STAGES:
The strain with the parent generation was bred and maintained in vessels containing a batch of Daphnia magna of different ages.
Preparing a new study, juvenile Daphnia magna were separated and placed in 100 ml of reconstituted water. The water was renewed and the Daphnia magna were fed with a suspension of fresh water algae once a week.
Newborn animals were separated and allocated to the different dose groups.

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

48 h

Hardness:

250 mg/L expressed as CaCO3

Test temperature:

22 - 23°C

pH:

7.73 - 7.92

Dissolved oxygen:

97.2 - 99.4

Salinity:

NA

Nominal and measured concentrations:

100 mg/L (nominal)

Details on test conditions:

TEST SYSTEM
- Type: open
- Material, size, fill volume: 25-mL all-glass containing 10 mL reconstituted water
- Aeration: The test medium was not aerated during the study.
- 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: According to ELENDT M4 (1990)
Macro nutrients (mg/L):
CaCl2 · 2H2O 293.8
MgSO4 · 7H2O 123.3
NaHCO3 64.8
KCl 5.8
Na2SiO3 · 9H2O 10
NaNO3 0.27
KH2PO4 0.14
K2HPO4 0.18

Trace elements (mg/L):
B 0.5
Fe 0.2
Mn 0.1
Li, Rb and Sr 0.05
Mo 0.025
Br 0.0125
Cu and Zn 0.0063
Co and J 0.0025
Se 0.0010
V 0.0003
Na2EDTA · 2H2O 2.5

Vitamins (μg/L):
Thiamine 75.0
B12 1.0
Biotin 0.75

- Culture medium different from test medium: no

OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: 16 hours light – 8 hours dark

EFFECT PARAMETERS MEASURED:
- The mobility was determined by visual control and recorded after 24 and 48 hours.

VEHICLE CONTROL PERFORMED: yes (vehicle was the reconstituted water)

Reference substance (positive control):

no

Remarks:

No positive control used in this study. The accuracy and reliability of the test method is demonstrated periodically as recommended by guidelines with potassium dichromate.

Key result

Duration:

24 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: water solubility was < 0.0975 mg/L

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: water solubility < 0.0975 mg/L

Details on results:

- Behavioural abnormalities: no
- Other biological observations: no
- Mortality of control: no
- Other adverse effects control: no
- Abnormal responses: no
- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: no

Validity criteria fulfilled:

yes

Conclusions:

The 48 hour EC50 for the test material to Daphnia magna could not be quantified due to the absence of toxicity at the highest test concentration achievable in water. An aqueous solution of 100 mg/L revealed no aquatic toxicity in the test system.

Executive summary:

The objective of this study was to determine the acute toxicity of test material in a static test to Daphnia magna. For this purpose, juvenile Daphnia magna were exposed to an aqueous test material solution over 48 hours, under defined conditions. The study comprised of four vessels per concentration containing five Daphnia magna, i.e. 20 Daphnia per concentration (test medium group). Daphnia magna were exposed to an aqueous solution from a test material concentration of nominal 0.1 g/L (limit-test) in an open system. After an exposure to a saturated aqueous solution of a nominal concentration of g/L for 48 hours to Daphnia magna, no immobilization was observed. Thus, Daphnia magna exposed to an aqueous solution of the nominal concentration of 0.1 g of the test item were not affected.

The analysis of a saturated aqueous solution revealed that the water solubility of the test item was < 0.0000975 g/L.

The limit of quantification of the analytical method was described to be about 0.000325 g/L. Therefore, the test material concentrations in the aqueous medium at the start and the end of the study could not be quantified. For the test material, the following nominal EC50 values for Daphnia magna were calculated: 24-h EC50 > 100 mg/L and 48-h EC50 > 100 mg/L.

Description of key information

The 48 hour EC50 for the test material to Daphnia magna could not be quantified due to the absence of toxicity at the highest test concentration achievable in water. An aqueous solution of 100 mg/L revealed no aquatic toxicity in the test system. Thus, the 48 -h EC50 was greater than 100 mg/L.

Additional information

The acute toxicity of the test material to Daphnia magna was investigated in a static test according to OECD Guideline 202. Daphnia magna exposed to an aqueous solution of the nominal concentration of 100 mg/L of the test item were not affected. Due to the low water solubility of the test item (< 0.0975 mg/L) the concentration of the test item in the aqueous medium could not be quantified. Thus, the EC50 value was determined to be greater than 100 mg/L (nominal concentration) after an exposure of 24 hours and 48 hours.