Bis(pentane-2,4-dionato-O,O')magnesium

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

Reliability:

1 (reliable without restriction)

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2017

Report date:

2017

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Version / remarks:

Regulatory Requirements:
In deviation to the Study Plan, also the Toxic Substances Control Act (TSCA, 1975) was included in the Regulatory Requirements. This deviation did not have any impact on test results.
Test item
EEC number is 628-792-9, as declared by the Sponsor. This deviation did not have any impact on test results.

Deviations:

yes

Remarks:

See in version/remarks above.

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

Bis(pentane-2,4-dionato-O,O')magnesium

EC Number:

237-857-7

EC Name:

Bis(pentane-2,4-dionato-O,O')magnesium

Cas Number:

14024-56-7

Molecular formula:

C10H14MgO4

IUPAC Name:

magnesium;4-oxopent-2-en-2-olate

Test material form:

solid: particulate/powder

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

Samples of test media were taken at time 0 and after 48 hours; final samples were obtained mixing the replicates.
Control samples were analysed at the same time to verify the absence of test item contamination.
Samples were labelled and analysed immediately after sampling.
Duplicate samples of the test water and the negative control were taken from the test solutions; one sample was analysed, while the respective duplicates were stored as retain samples to be analysed only if necessary.

Test solutions

Vehicle:

no

Details on test solutions:

The test was performed at five test item concentrations in a geometric series (differing by a constant factor equal to 2.2), namely 4.3, 9.4, 20.7, 45.5 and 100.0 mg/L of test item N56.
The test medium was prepared as follows:
prior to the test start, a 100.0 mg/L test item stock solution was prepared by direct weighing into reconstituted water (0.0501 g of test item into 501 mL of reconstituted water).
The obtained solution was clear and the test item was completely solubilised. Starting from this stock solution, the test item solutions were prepared by dilution with reconstituted water as reported below.
The obtained solutions were transparent and clear; after pH and oxygen concentration check, the test started.
A negative control with reconstituted water only was also tested.

test solutions preparation:
Test solution 1:
-nominal test item solution concentration : 4.3mg/L
-final volume : 200mL
-added volume of test item stock solution 100.0 mg/L: 8.6mL

Test solution 2:
-nominal test item solution concentration : 9.4mg/L
-final volume : 200mL
-added volume of test item stock solution 100.0 mg/L: 18.8mL

Test solution 3:
-nominal test item solution concentration : 20.7mg/L
-final volume : 200mL
-added volume of test item stock solution 100.0 mg/L: 41.4mL

Test solution 4:
-nominal test item solution concentration : 45.5mg/L
-final volume : 200mL
-added volume of test item stock solution 100.0 mg/L: 91mL

Experimental conditions
The treatment vessels were identified by experiment number, group and replicate number.

Test organisms

Test organisms (species):

Daphnia magna

Details on test organisms:

The study was performed on the freshwater crustacean Daphnia magna Straus. A strain of this species was supplied by MicroBioTests Inc., Belgium in December 2011 (batch number: DM290911).
Since that time, the clone has been bred in the laboratories of the Test Facility under conditions identical to those of the test, with regard to temperature, light and water quality, so that no acclimation was needed prior to testing.
It was daily fed with a fixed amount of the laboratory cultured green algae Pseudokirchneriella subcapitata (formerly Selenastrum capricornutum) and with a suspension of the yeast Saccharomyces cerevisiae.
At the test start the organisms used in the test were less than 24 hours old and were not first brood progeny.

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Test conditions

Hardness:

140 - 250 mg/L as CaCO3

Test temperature:

The incubation temperature was continuously monitored during the course of the study by a PT100 probe installed in the environmental test chamber. It was constant at 20.0°C during the test period with a standard deviation of 0.02 °C. The temperature range provided by OECD guideline 202, 2004 is 20 ± 2°C. The temperature values during the test were within the provided range and did not vary more than 1°C during the test period.

pH:

The pH of the test medium in fresh solutions was within the provided range (pH 6 – 9) and did not vary by more than 0.66 units during the test period, as required in the mentioned guideline.

Dissolved oxygen:

The dissolved oxygen concentration in the negative control and in the test media was always higher than 6.0 mg/L according to OECD Guideline No. 202 that provides a minimum oxygen concentration of 3.0 mg/L.

Conductivity:

< 5 μScm^1

Reference substance (positive control):

no

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

24 h

Dose descriptor:

EC0

Effect conc.:

ca. 18.6 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Effect concentrations 2

Duration:

24 h

Dose descriptor:

EC50

Effect conc.:

> 91 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Effect concentrations 3

Duration:

24 h

Dose descriptor:

EC100

Effect conc.:

> 91 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Effect concentrations 4

Duration:

24 h

Dose descriptor:

NOEC

Effect conc.:

ca. 91 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Effect concentrations 5

Duration:

48 h

Dose descriptor:

EC0

Effect conc.:

ca. 4 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Effect concentrations 6

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 91 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Effect concentrations 7

Duration:

48 h

Dose descriptor:

EC100

Effect conc.:

> 91 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Effect concentrations 8

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

ca. 40 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

Immobilization after 24 and 48 hours of exposure was compared with corresponding parameters in the negative control.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Executive summary:

The Short-term toxicity to aquatic invertebrates test was performed according to the OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test).

The EC50 (24 and 48h) on immobilization parameter in Daphnia magna was >91mg/L.

The NOEC (24h) was 91 mg/L and the NOEC (48h)was 40mg/L