Mixed metal oxide complex

Short-term toxicity to aquatic invertebrates

Administrative data

Endpoint:

short-term toxicity to aquatic invertebrates

Remarks:

Daphnia magna acute immobilisation test

Type of information:

experimental study

Adequacy of study:

key study

Study period:

27 July - 11 August 2016

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2016

Report date:

2016

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Version / remarks:

updated 13th April 2004

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Version / remarks:

Dated May 30, 2008

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

impurity 1

Test material form:

solid: particulate/powder

Details on test material:

Batch No.: 2016JAN-15kg
Expiry Date: 01 January 2020
Appearance: Blue-white powder
Storage: Room temperature (15-25°C)
Safety precautions: Routine safety precautions (lab coat, gloves, safety glasses, face mask) for unknown materials were applied to assure personnel health and safety.

Specific details on test material used for the study:

Test item: Neodymium fluoride oxide, magnesium doped
Batch No.: 2016JAN-15kg
Expiry Date: 01 January 2020
Appearance: Blue-white powder
Storage: Room temperature (15-25°C)

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

At the start of the study five replicate samples (12 ml) were taken from the test solution, at the end four samples were taken (one sample from each test vessel). One control sample was analysed on both analytical occasions. Before the ICP-OES analysis 2% nitric acid was added to the samples.

Test solutions

Vehicle:

no

Details on test solutions:

For preparation of test solution a supersaturated solution (100 mg/L nominal loading) was prepared by adding an amount of 0.05 g test item in 500 mL test medium (ISO medium). This supersaturated solution was shaken for at least two days and thereafter the non-dissolved test material was removed by filtration through a 0.22 µm membrane filter to obtain the saturated test solution. The test solution was freshly prepared in the testing laboratory just before introduction of the test animals (start of the experiment).

Test organisms

Test organisms (species):

Daphnia magna

Details on test organisms:

Species and strain: Daphnia magna (Straus)
Origin: Laboratory of Hydrobiology (Central Agricultural Office, Directorate of Plant-, and Soil Protection) 2100 Gödöllő, Kotlán S. u. 3. Hungary
Breeding: The Daphnia are bred in the Laboratory of TOXI-COOP ZRT.
Number of animals: Twenty animals in both groups (concentration and untreated control), divided into 4 concurrent batches (5 animals per batch).
Age of animals: Less than 24 h old at the beginning of the test.
Sex: Female
Animal health: Apparently healthy animals were used in this test with a known history
Acclimatization: Test animals were bred under similar (or the same) conditions as that used during the exposure period (holding water, temperature, background colour etc.), therefore additional acclimatisation before the test was not necessary. Brood daphnids were maintained in dilution water at the test temperature for at least 48 hours prior to the start of the test.
Food and Feeding: The Daphnia were fed with concentrated algal suspension of Raphidocelis subcapitata during the holding. Test animals were not fed during the exposure.

Study design

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

48 h

Test conditions

Hardness:

The reconstituted water (ISO medium) has an approximate theoretical total hardness of 249 mg/L (as CaCO3)

Test temperature:

The test temperature was in the range of 20.2 – 20.5°C measured in the test vessels during the test. The additionally measured ambient temperature within the climate chamber was between 20.1 – 21.0°C.

pH:

The pH of the test solution was not adjusted and not varied by more than 1.5 units in any one test. The pH was in the range of 7.67 – 7.96 during the test.

Dissolved oxygen:

The dissolved oxygen concentration was in the range of 7.54 – 8.08 mg/L during the test.

Nominal and measured concentrations:

A saturated test item solution (limit concentration) and a concurrent control were included in the main test. The concentration of the test item was analytically determined at the start and at the end of the experiment. The test item was not detected in the untreated control group (i.e. signal intensities measured for the control samples were less than 20 % of the analytical quantification limit (LOQ)). In the treated group mean of the measured concentrations was 0.065 mg/L at the start and 0.050 mg/L at the end of the test. The exposure concentration was calculated as the geometric mean of the start and end values and determined to be 0.06 mg/L. This concentration was considered as the saturation concentration in the test medium (equivalent to 100 mg/L nominal concentration).

Details on test conditions:

Twenty animals, divided into four groups (glass beaker; volume app. 50 mL) of five animals each (at least 4 mL test solution/animal) were exposed to the treatment group or included as control over a period of 48 hours. The test animals were not fed during the test. Each test vessel contained approximately 40 mL of test solution and was uniquely identified with study code, test group and replicate. Daphnia were observed for immobility or mortality by visual observation after 24 and 48 hours of exposure. Those animals not able to swim within 15 seconds after gentle agitation of the test beaker were considered to be immobile. Reconstituted water (ISO medium, according to OECD 202) was used as dilution water in the experiment. Separate stock solutions of individual substances were first prepared in deionised water (prepared in TOXI-COOP ZRT. by MILLIPORE ELIX 3 water purification system). The ISO medium was prepared by adding 25 mL from each of four stock solutions to one litre deionised water.

Reference substance (positive control):

yes

Results and discussion

Effect concentrations

Effect concentrations 1

Key result

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

> 0.06 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Effect concentrations 2

Key result

Duration:

48 h

Dose descriptor:

EC10

Effect conc.:

> 0.06 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Effect concentrations 3

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 0.06 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

There was no immobilisation observed in twenty daphnids exposed to either test item treated or control group. In addition to immobility, no abnormal behaviour or appearance of test animals was detected.

Results with reference substance (positive control):

For the evaluation of the quality of the Daphnia clone and the experimental conditions, Potassium dichromate is tested at least twice a year to demonstrate satisfactory test conditions. The date of the last study (Study Code: 392-202-1334) with reference item Potassium dichromate was: 01 – 02 March 2016. The 24h EC50 value was determined to be 1.26 mg/L (95% conf. limits: 1.11 – 1.55 mg/L).

Name and data of Reference Item
Name: Potassium dichromate (K2Cr2O7)
Batch No.: MKBN3524V
Description: Orange crystalline powder
Expiry Date: 04 March, 2018
Storage: Room temperature
Supplier: SIGMA-ALDRICH

Reported statistics and error estimates:

Not relevant in this limit test

Any other information on results incl. tables

Summary of the Biological Endpoints

Endpoints	Concentration
48 h-EC10	> 0.06 mg/L(equivalent to > 100 mg/L nominal)
48 h-EC20	> 0.06 mg/L(equivalent to > 100 mg/L nominal)
48 h-EC500	> 0.06 mg/L(equivalent to > 100 mg/L nominal)
48 h-NOEC	0.06 mg/L(equivalent to 100 mg/L nominal)
48 h-LOEC	> 0.06 mg/L(equivalent to > 100 mg/L nominal)

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

Based on the results of this study, the test item Neodymium fluoride oxide, magnesium doped had no toxic effect at aquatic saturation (i.e. limit test concentration) on Daphnia magna; the EC10, EC20, EC50 results and the LOEC are higher than the solubility level of the test item in the test medium, which corresponds to a nominal concentration of 100 mg/L. (measured geometric mean concentration 0.06 mg/L)

Executive summary:

The substance Neodymium fluoride oxide, magnesium doped was assessed using Daphniamagnain a 48-hour Acute Immobilisation Test. Young Daphniawere exposed to aqueous test media containing the test item for 48 hours in a static test.

A limit test was performed in which, the test animals were exposed to aqueous test media containing the test item for 48 hours at the limit of its solubility in the test medium (i.e. saturation) plus a control in order to demonstrate that the test item has no influence on the mobility of Daphniaup to at least the saturation concentration (equivalent to 100 mg/L nominal concentration).

The quantification of the test itemNeodymium fluoride oxide, magnesium dopedwas performed by a previously validated analytical method by the analytical laboratory of TOXI-COOP ZRT. Samples were taken from the test concentration and the control at the start and at the end of the experiment and analysed by ICP-OES methodbased on the measured neodymium content. The determined exposure concentration of the test item was 0.06 mg/L which was calculated as the geometric mean of the measured start and end concentrations.

Healthy, young female daphnids with known origin, history and acclimatisation conditions were used. Twenty Daphnia (divided into 4 concurrent batches) were tested each, exposed to the saturated test concentration and in the control. Each test vessel contained approximately 40 mL test medium.Fully characterized (content, physico-chemical characteristics) ISO Medium was used as test medium.

The immobilisation of the test animals was recorded 24 and 48 hours after treatment. Environmental conditions were recorded. All measured values remained within acceptable ranges.

There was no immobilisation in twenty daphnids exposed to either test item treated or control group. In addition to immobility, no abnormal behaviour or appearance of test animals was detected.

All validity criteria were met and therefore the study can be considered as valid.