Zirconium praseodymium yellow zircon

Toxicity to aquatic algae and cyanobacteria

Administrative data

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

2010-10-18 to 2010-10-21

Reliability:

3 (not reliable)

Rationale for reliability incl. deficiencies:

significant methodological deficiencies

Remarks:

- chemical analysis not reported; -test solutions were only stirred for < 3 days instead of shaken for 7 days (to collect 7-d T/D fraction of metal substances in accordance with CLP acute hazard criteria and OECD Series 29); - temperature not in range of 21-24°C (controlled at ± 2°C) but ranged from 23.0 – 26.3 °C.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2010

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

signed 2009-06-19

Test material

Test material information

Constituent 1

Reference substance name:

Zirconium praseodymium yellow zircon

EC Number:

269-075-7

EC Name:

Zirconium praseodymium yellow zircon

Cas Number:

68187-15-5

Molecular formula:

Pr(x)Zr(1-x)SiO4 0,03≤x≤0,09

IUPAC Name:

silicon(4+) zirconium(4+) λ⁴-praseodymium(4+) dipraseodymium(3+) nonaoxidandiide

Test material form:

solid: particulate/powder

Details on test material:

- Name: Colorante amarillo
- EC Name: Zirconium Praseodymium Yellow Zircon
- Substance type: inorganic pigment
- Physical state: solid, yellow powder, odourless
- Storage condition of test material: at room temperature

Sampling and analysis

Analytical monitoring:

no

Test solutions

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION:
Prior to the start of the test, a solution of 100 mg/L was prepared by direct weighting into algal culture medium (0.1007 g of test item into 1000 mL of algal culture medium). The obtained solution showed yellow insoluble dust, therefore it was mixed by the means of a magnetic stirrer (Magnetic stirrer type AGE, Velp Scientific, ChemService code No. 453) for about 65 hours to reach the maximum solubilisation of test item, then the obtained suspension was filtered by a glass filtering system (45µm filter pore) to obtain a clear solution, used as test medium.

Test organisms

Test organisms (species):

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

Details on test organisms:

TEST ORGANISM
- Common name: Pseudokirchneriella subcapitata strain
- Strain:
- Source (laboratory, culture collection): cultured in the ChemService laboratory and originally purchased from the Institute of Plant Physiology of the University of Göttingen, Germany
- Age of inoculum (at test initiation):
- Method of cultivation:

CULTIVATION/ACCLIMATION
The algae were cultured in a temperature controlled room at 24.0 °C ± 2.0 °C under continuous uniform illumination of approximately 6000 Lux in the spectral range 400-700 nm. The culture medium was the same of the test medium; the stock cultures were weekly transferred to fresh medium and maintained in continuous shaking to ensure the necessary amount of CO2 and to keep algae in suspension. Cultures containing deformed or abnormal cells were discarded. Only exponentially growing algal cultures have been used to start the test.

Study design

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

72 h

Test conditions

Test temperature:

The ambient temperature under the lights was continuously measured by the mean of a data logger. It was in the range 23.0 – 26.3 °C during the test period.

pH:

At the beginning of the test period, the pH of the test medium was 8.07 for the test item and 8.11 for the control while the pH mean values at the end of the test were, respectively, 9.48 for the control and 9.52 for test item solution.

Nominal and measured concentrations:

Nominal test item concentration: 100 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: For the test concentration and for the negative control, 100 mL capacity conical glass flasks capped with air permeable stoppers were used.
- Initial cells density: At the start of the test, 50 mL of test solution were poured into the test flasks and inoculated with algae to obtain a starting cell density of around 10E4 cells/mL
- Cell density of the inoculum: 10E6 cells/mL
- Control end cells density: 202 * 10E4 cells/mL
- No. of vessels per concentration (replicates): 6
- No. of vessels per control (replicates): 6

GROWTH MEDIUM
- Standard medium used: yes

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: deionised water
- Conductivity: conductivity < 5 µScm-1
- Culture medium different from test medium: no
- Intervals of water quality measurement: pH was measured in the test item solution and in the algal culture medium at the beginning of the test and in each test flask at the end of the test. Mean values over the replicates are reported.

OTHER TEST CONDITIONS
- Sterile test conditions: yes
- Photoperiod: continuous illumination
- Light intensity and quality: light intensity was ranged between 4953 and 4985 Lux (Lux-meter , Testo 545, ChemService code No. 252)

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: Algal cell density was measured every 24 hours by fluorescent reading with a spectrofluorophotometer (Spectrofluorophotometer Shimadzu RF-1501, ChemService code No. 99) in few millilitre samples taken from each test concentration replicate and from controls.

TEST CONCENTRATIONS
- Range finding study: Since no adverse effects were showed from range-finding test, the main study was carried out at the only nominal concentration of 100 mg/L (Limit Test), a negative control with algal culture medium only was also tested.

Reference substance (positive control):

yes

Remarks:

3,5-dichlorophenol pestanal analytical standard

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 2

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 3

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Effect concentrations 4

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Details on results:

- Exponential growth in the control (for algal test): yes

Results with reference substance (positive control):

- Results with reference substance valid are valid
- EC50: 4.40 mg/L

Reported statistics and error estimates:

The CETIS v.1.026D software was used to carry out the statistical analysis which automatically selects the most appropriated statistic analysis. The statistical comparison with the control at each observation time was determined by Bonferroni adjusted test for both the endpoints, growth rate and yield, after analyzing the normality of distribution and the homogeneity of variance by Shapiro-Wilk and Barlett’s test respectively. The EyCx and the ErCx values were determined by a linear interpolation analysis, chosen by the PC software as more appropriate.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Remarks:

Temperature range: 23.0 - 26.3 °C instead of 21- 24.0 ± 2.0 °C (OECD 201), Chemical analysis not reported, 3-d stirring of solutions instead of 7-d shaking (to collect 7-d T/D fraction of metal substances acc to CLP acute hazard criteria & OECD Series 29)

Conclusions:

The toxicity of the test item Zirconium praseodymium yellow zircon was tested on Pseudokirchneriella subcapitata. The EC10, EC20 and EC50 for growth rate and for yield were determined to be greater than the nominal tested concentration of 100.0 mg/L.