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

Toxicity to aquatic algae and cyanobacteria

Administrative data

Endpoint:

toxicity to aquatic algae and cyanobacteria

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 201 (Alga, Growth Inhibition Test)

Version / remarks:

Deviations from the study plan:
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 72 hours; final samples were obtained mixing the replicates and they were immediately centrifuged to separate the algae from the medium.
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 3.2), namely 1.0, 3.1, 9.8, 31.3 and 100.0 mg/L of test item

test solutions preparation:
Test solution 1:
-nominal test item solution concentration : 1mg/L
-final volume : 200mL
-added volume of test item stock solution 100.0 mg/L: 2mL

Test solution 2:
-nominal test item solution concentration : 3.1mg/L
-final volume : 200mL
-added volume of test item stock solution 100.0 mg/L: 6.2mL

Test solution 3:
-nominal test item solution concentration : 9.8mg/L
-final volume : 200mL
-added volume of test item stock solution 100.0 mg/L: 19.6

Test solution 4:
-nominal test item solution concentration : 31.3mg/L
-final volume : 200mL
-added volume of test item stock solution 100.0 mg/L: 62.6mL

Experimental conditions
The treatment vessels were identified by experiment number, group and replicate number.
All the described procedures were conducted under a laminar flow bench to ensure the sterility of the algal cultures.
For the test concentrations and for the negative control, 100 mL capacity conical glass flasks capped with air permeable stoppers were used.
Three replicates for each test concentrations and six for negative control were prepared. At test start, 50 mL of test solutions were poured into the test flasks and inoculated with algae to obtain a starting cell density of about 10^4 cells/mL.
The inoculum was taken from a pre-culture started 3 days before the test beginning (containing approximately 10^6 cells/mL), in order to ensure that the assay was performed with an exponentially growing population.
The test flasks were incubated in an environmental test chamber, under continuous illumination and constant shaking. The flasks were randomly distributed under the light and replaced every day during the test.

Test organisms

Test organisms (species):

Raphidocelis subcapitata (previous names: Pseudokirchneriella subcapitata, Selenastrum capricornutum)

Study design

Test type:

not specified

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Test conditions

Test temperature:

24.0 – 24.1 °C

pH:

pH of test medium: 7.88 – 8.91 at the test start
7.35 – 8.13 at the test end

Conductivity:

< 5 μScm^-1)

Reference substance (positive control):

no

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

>= 8.7 - <= 9.8 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 2

Duration:

72 h

Dose descriptor:

EC20

Effect conc.:

>= 11.3 - <= 12.5 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 3

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

>= 22.3 - <= 27.4 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 4

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

ca. 2.4 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 5

Duration:

72 h

Dose descriptor:

LOEC

Effect conc.:

ca. 8 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Executive summary:

The toxicity to aquatic algae and cyanobacteria test was performed according to the OECD Guideline 201 (Alga, Growth Inhibition Test).

The EC50 (72h) in algae Pseudokirchneriella subcapitata was between 22.3 and 27.4mg/L.

The NOEC was 2.4 mg/L and the LOEC was 8mg/L