Niobium sulfur tin zinc oxide

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

Study period:

13 Dec - 16 Dec 2011

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2012

Report date:

2012

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Version / remarks:

adopted in 2006

GLP compliance:

yes (incl. QA statement)

Remarks:

Standards Council of Canada, Ottawa, Canada

Test material

Test material information

Constituent 1

Reference substance name:

niobium oxygen sulfur zinc λ²-stannane

EC Number:

800-035-9

Cas Number:

1374645-21-2

Molecular formula:

Sn1.8Zn0.2Nb2O6.8S0.2 (Sn(2-x)Zn(x)Nb2O(7-y)S(y) with x/2 ≤ y, 0.02 ≤ x ≤ 0.22, 0.01 ≤ y ≤ 0.22)

IUPAC Name:

niobium oxygen sulfur zinc λ²-stannane

Details on test material:

- Name of test material (as cited in study report): EX1455, Niobium Sulfur Tin Zinc Oxide
- Physical state: Solid, yellow powder
- Analytical purity: 100%
- Lot/batch No.: L1903
- Storage condition of test material: At ambient temperature and out of direct sunlight

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

- Concentrations: All concentrations were sampled.
- Sampling method: Duplicate 100 mL samples were collected immediately at test start (0 h) and at test termination (72 h, pooled replicates).
- Sample storage conditions before analysis: Samples were preserved using HNO3 for total metals and filtered and preserved using HNO3 for dissolved metals. Samples were refrigerated until analysis.

Test solutions

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: Preparation of the test solutions followed OECD’s Guidance Document on Aquatic Toxicity Testing on Difficult Substances and Mixtures (OECD, 2000). A nominal concentration of 100 mg/L was selected as the maximum concentration of the test item to be tested for all range finding and definitive tests.
For the range-finding test, a 1 L solution of a 100 mg/L nominal concentration was prepared by adding 50.04 mg of EX1455 into 500 mL of filter-sterilised algal nutrient medium in an appropriate container and stirring for 1 h at room temperature. This solution was settled for approx. 2 h. At this time visible solids were still present in solution, in contrast the results of a preliminary test with Daphnia magna, where the solid material had settled within 3 h. Despite the presence of solid material in solution, preparation of the remaining test solutions was completed at this time. A total of 500 mL of the 100 mg/L test solution was decanted for testing leaving the settled solids behind. All lower concentrations of the test item were prepared by serial dilution.
For the definitive test (limit-test), a single exposure concentration of 100 mg/L was prepared by adding 100.05 mg of the test item into 1 L of filter sterilized nutrient medium in an appropriate container and stirring for 1 h at room temperature. This solution was settled for 48 h.

Test organisms

Test organisms (species):

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

Details on test organisms:

TEST ORGANISM
- Source (laboratory, culture collection): Laboratory culture since 1999; originally obtained from the University of Texas (UTEX 1648).
- Method of cultivation: Cultures are aseptically transferred twice weekly (typically from 3 – 7 day old donors) and maintained in temperature and light controlled environments isolated from all testing. The axenic nature of the stock culture is verified by plating on Trypticase Soy Agar (TSA) and Plate Count Agar (PCA).

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Test conditions

Test temperature:

22 °C constant temperature

pH:

7.3 - 7.5

Nominal and measured concentrations:

Nominal: 0 and 100 mg/L
Measured (dissolved after 72 h) for nominal 0 mg/L: < LOD (tin, zinc, niobium) and 1.078 – 1.463 mg/L (sulfur)
Measured (dissolved after 72 h) for nominal 100 mg/L: < LOD (tin and niobium), 0.007 - 0.010 mg/L (zinc) and 1.231 – 1.737 mg/L (sulfur)
Measured (total after 72 h) for nominal 100 mg/L: < LOD (tin and niobium), 0.009 - 0.011 mg/L (zinc) and 1.347 – 1.490 mg/L (sulfur)

Details on test conditions:

TEST SYSTEM
- Test vessel: Erlenmeyer flasks
- Type (delete if not applicable): closed
- Material, size, fill volume: Glass, 250 mL, 50 mL
- Shaking: Continuous shaking on a rotary shaker at 100 rpm
- Initial cells density: 8275 cells/mL
- Control end cells density:2.4E06 cells/mL
- No. of vessels per concentration (replicates): 6
- No. of vessels per control (replicates): 6

GROWTH MEDIUM
- Standard medium used: yes; Environment Canada (2007) medium which meets the nutrient requirements of the OECD guideline.

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Nanopure II water free of particles, ions, organic molecules and microorganisms greater than 0.45 µm. Nutrient medium is filter sterilised prior to use in cultures and in testing.
- Total organic carbon: < 2 mg/L
- Intervals of water quality measurement: pH values are measured at test start and test end.

OTHER TEST CONDITIONS
- Sterile test conditions: yes
- Adjustment of pH: No
- Photoperiod: Continuous illumination
- Light intensity and quality: 6406 - 6707 lux, cool-white fluorescent

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: At 0, 24, 48 and 72 h using a haemocytometer
- Other: Observation of changes in cell development or appearance

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 10
- Range finding study
- Test concentrations: 0, 0.001, 0.01, 0.1, 1.0, 10 and 100 mg/L
- Results used to determine the conditions for the definitive study: No effects in the range of water solubility were observed.

Reference substance (positive control):

no

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

72 h

Dose descriptor:

EL50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

WAF

Basis for effect:

growth rate

Remarks on result:

other: Test item solution was stirred for 2 h and then allowed to settle for 48 h; decanted solution was used for testing.

Effect concentrations 2

Duration:

72 h

Dose descriptor:

EL50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

WAF

Basis for effect:

other: yield

Remarks on result:

other: Test item solution was stirred for 2 h and then allowed to settle for 48 h; decanted solution was used for testing.

Details on results:

- Exponential growth in the control (for algal test): yes, multiplication factor of 290
- Effect concentrations exceeding solubility of substance in test medium: Yes

Reported statistics and error estimates:

Calculations of effect concentrations were conducted using the Equal Variance Two-Sample Test (CETIS, 2007).