Tin dioxide

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

from 13th March 2012 to 18th April 2012

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP study in compliance with international recognized guidelines

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Deviations:

no

GLP compliance:

yes

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source and lot/batch number of test material:
2012-000203
- Expiration date of the lot/batch:
07/02/2013, W0167
- Purity test date:
> 99.9%, 23/01/2011



INFORMATION ON NANOMATERIALS
- Chemical Composition:
Tin Dioxide
- Density:
6.936 g/cm³
- Particle size & distribution:
10-100 nm; 78
- Specific surface area: 7.4293 ± 0.0132 m²/g

Analytical monitoring:

yes

Details on sampling:

The concentration of tin dioxide was verified in the test medium over the whole period of 3 days.
Samples were taken and analysed at test start from fresh solution and after 72h from aged test solution at all concentration levels.

Details on test solutions:

Two stock solutions were prepared by directly weighting 100 and 31.3 mg of the test item into 1000 ml test medium, respectively. the stock solutions were reared for 47h, and filtered through an filter with µm pore size. the further concentrations were made by diluting the appropriate solutions to give the required test concentrations.

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

The algae used in this study were purchased as SAG strain no. 86.81 from the Georg-August-Univarsitat Gottingen, Wilhelmsplatz 1, 37073 Gottingen, Germany.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

3 d

Post exposure observation period:

no data.

Hardness:

no data, composition according to the guideline.

Test temperature:

22.0 - 23.6°C

pH:

7.66 - 8.85

Dissolved oxygen:

not reported

Salinity:

no data, composition according to the guideline.

Nominal and measured concentrations:

The main test was performed with the following range of test item concentrations: 0.0931, 0.298, 0.954, 3.05, 9.77, 31.3 and 100 mg/L.
Tin dioxide was verified in test medium by analysing the content in the samples over the whole period of 3 days. samples were taken and anlysed at test start from fresh solutions and after 72 h from aged test solution at all concentrations levels.
The solubility of tin from tin dioxide in double distilled water at 20°C is below the limit of quantification (2.5 µg/L) - see endpoint "water solubility" - Therefore the assessment of toxicological results was based on nominal concentration.

Details on test conditions:

TEST SYSTEM
- Test vessel: sterile, 500-mL Erlenmeyer flasks
- Initial cells density: 0.5 X 10^4 cells/mL
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 6

TEST MEDIUM:
Test medium used according to AAP-Medium, Annex 3 of the OECD 201)
One millilitre of each stock solutions was used for 1 litre test medium.


OTHER TEST CONDITIONS
- Sterile test conditions: yes
- Light: continuous illumination at 4400 - 5600 lux at cell culture level.

Reference substance (positive control):

no

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

9.77 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

LOEC

Effect conc.:

31.3 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Details on results:

Statistically significant inhibitory effects were observed after 72h in the concentration 31.3mg/L for growth rate and 100mg/L for yield. The dose response for growth rate was not clear so the lower test item concentration of 31.3mg/L was determined as NOEC.

Results with reference substance (positive control):

not applicable

Reported statistics and error estimates:

the field"illustration" reports the p-value of the statistical evaluation.

Validity criteria fulfilled:

yes

Remarks:

the test fulfils the validity criteria in accordance with OECD guideline for testing of chemicals No. 201

Conclusions:

Statistically significant difference to the control were determined at 31.3 and 100 mg/L.
No EC50-values were determined due to the fact that the inhibitory effects were below 50%. Therefore the EC50-value for growth rate and yeld was estimated to be > 100mg/L. The LOEC is estimated to be 31.3 mg/L, the NOAEC was determined to be 9.77 mg/L.

Description of key information

The substance was not toxic to algae when tested according to OECD guideline 201 (Alga, Growth Inhibition Test), with a 72-hour EC50 value greater than 100 mg/L
EC50 (Algae, 72 hr, OECD 201): > 100 mg/L
NOEC (Algae, 72 h, OECD 201): 9.77 mg/L
LOEC (Algae, 72 h, OECD 201): 31.3 mg/L

Additional information

Statistically significant differences to the control were determined at 31.3 and 100 mg/L. No EC50-values were determined due to the fact that the inhibitory effects were below 50%. Therefore the EC50-value for growth rate and yield was estimated to be > 100mg/L. The LOEC is estimated to be 31.3 mg/L, the NOAEC was determined to be 9.77 mg/L.

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