RSS-4, DRY SUBSTANCE

Short-term toxicity to fish

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

key study

Study period:

April-May 2012

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method C.1 (Acute Toxicity for Fish)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

During the final limit test singular samples for possible analysis were taken from the control and the limit concentration according to the schedule below.

Frequency at t=0 h and t=96 h
Volume 2 mL
Storage Samples were stored in a freezer until analysis.

Additionally, singular reserve samples of 2 mL were taken from all test solutions for possible analysis. If not already used, these samples were stored in a freezer for a maximum of three months after delivery of the draft report, pending on the decision of the sponsor for additional analysis.

Vehicle:

no

Details on test solutions:

The batch of Magnesium bis (2-ethylbutanoate) tested was a white powder with crystals and a purity of 94.0 %.

Preparation of test solutions started with the highest test concentration of 100 mg/L applying a short period of ultrasonic treatment followed by two days of magnetic stirring in order to achieve maximum dissolution. This resulted in a clear solution that was used as such in the range-finding test or in clear solution with undissolved material floating at the surface in the final test. The floating material was removed by filtration through a 0.45 µm membrane filter (Whatman, RC55). The lower test concentrations were prepared by subsequent dilution in test medium. The final test solutions were all clear and colourless.

Test organisms (species):

Cyprinus carpio

Details on test organisms:

- Common name: Carp (Cyprinus carpio, Teleostei, Cyprinidae)
- Source: Zodiac, proefacc, "De Haar Vissen", Wageningen University and Research Centre, The Netherlands
- Length at study initiation (length definition, mean, range and SD): Final test: 2.8 ± 0.2 cm
- Weight at study initiation (mean and range, SD): Final test: 0.65 ± 0.09 g
- Feeding during test: no feeding
ACCLIMATION
- Acclimation period: At least 12 days after delivery
- Acclimation conditions (same as test or not): same as the test
- Feeding: Daily with pelleted fish food (Trouvit)
- Health during acclimation (any mortality observed): In the batch of fish used for the test, mortality during the seven days prior to the start of the test was less than 5 %.

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

96 h

Hardness:

180 mg/L expressed as CaCO3

Test temperature:

Between 21.0 and 21.7 °C

pH:

Between 7.5 and 7.9

Dissolved oxygen:

Between 4.3 and 9.5 mg O2/L

Nominal and measured concentrations:

Nominal concentrations: control and 100 mg/L (0.45 µm filtered).
Measured concentration: 115 mg/L.

Details on test conditions:

- Test vessel:
- Aeration:
- No. of organisms per vessel: 7
- No. of vessels per concentration (replicates):1
- No. of vessels per control (replicates):1
- Biomass loading rate: 0.25 gram fish/litre

TEST MEDIUM / WATER PARAMETERS
Adjusted ISO medium, formulated using RO-water (tap-water purified by reverse osmosis; GEON Waterbehandeling, Berkel-Enschot, The Netherlands) with the following composition:
CaCl2.2H2O: 211.5 mg/L
MgSO4.7H2O: 88.8 mg/L
NaHCO3: 46.7 mg/L
KCl: 4.2 mg/L
- Intervals of water quality measurement: Dissolved oxygen content pH and temperature, Daily in all vessels with surviving fish, beginning at the start of the test (day 0).

OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: 16 hours photoperiod daily

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :LC50 t=24, 48, 72, 96 h

TEST CONCENTRATIONS
- Range-finding test: Three fish per concentration were exposed to a range of 0.1 to 100 mg/L increasing by a factor of 10.
Final study: Seven fish per test group exposed to a control and a 0.45 um filtered solution prepared at 100 mg/L.

Reference substance (positive control):

yes

Remarks:

pentachlorophenol (PCP)

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

> 115 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Duration:

96 h

Dose descriptor:

NOEC

Effect conc.:

115 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

other: abnormalities

Details on results:

Behavioral abnormalities:
- Mortality of control: No mortality in control
- Abnormal responses: no abnormalities were observed
- Effect concentrations exceeding solubility of substance in test medium: no

Results with reference substance (positive control):

Under the conditions of the present test with carp exposed to PCP, the 96h-LC50 was 0.25 mg/L based on nominal concentrations, with a 95% confidence interval between 0.20 and 0.41 mg/L. This effect was already reached within 24 hours of exposure.

Validity criteria fulfilled:

yes

Conclusions:

Magnesium bis(2-ethylbutanoate) induced no visible effects in carp at or below a measured concentration of 115 mg/L (NOEC).
The 96h-LC50 exceeded 115 mg/L based on actual measured concentrations.

Executive summary:

The 96h-LC50 to carp was determined in a limit test at a nominal concentration of 100 mg/L according to OECD guideline 203 and EU method C.1, in accordance with GLP. The measured concentration of filtered medium, determined by LC-MS analysis was 115 mg/L. Magnesium bis(2-ethylbutanoate) induced no visible effects in carp at or below a measured concentration of 115 mg/L (NOEC).

The 96h-LC50 exceeded 115 mg/L based on actual measured concentrations.

Description of key information

The 96h-LC50 to carp was determined in a limit test at a nominal concentration of 100 mg/L according to OECD guideline 203 and EU method C.1, in accordance with GLP. The measured concentration of filtered medium, determined by LC-MS analysis was 115 mg/L.
Magnesium bis (2-ethylbutanoate) induced no visible effects in carp at or below a measured concentration of 115 mg/L (NOEC).
The 96h-LC50 exceeded 115 mg/L based on actual measured concentrations.