Dialuminium zinc tetraoxide

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:

04 Apr - 02 May 2005

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Guideline study, non-GLP, no analytical concentration control

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Deviations:

yes

Remarks:

The initial biomass concentration 13600 cells/mL is not within the range 2000 - 5000 cells/mL recommended by the guideline for Desmodesmus subspicatus.

GLP compliance:

not specified

Analytical monitoring:

no

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
The test item wa directly dissolved in test medium. 0.010 g test item was weighed per test vessel. The vessels were filled with test medium up to 99.7 mL. 0.3 mL algae inoculum was added to each prepared solution.

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

TEST ORGANISM
- Common name: freshwater green algae
- Strain: 86.86 SAG
- Source (laboratory, culture collection): Albrecht-v.-Haller-Institut für Pflanzenwissenschaften; Sammlung von Algenkulturen, Göttingen, Germany
- Method of cultivation: cultures in logarithmic growth phase, axenic stock cultures grew in culturing vessels for 4 days prior to test initiation; cultivation was performed in glass flasks (250 mL) in medium; algae were kept at the same temperature and light conditions as during the test

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

72 h

Test temperature:

22.4 - 22.8 °C

pH:

8.08 - 8.92

Nominal and measured concentrations:

nominal: 0 and 100 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel:
- Type (delete if not applicable): closed with metal cap
- Size, fill volume: Erlenmeyer flask, 250 mL, fill volume 100 mL
- Initial cells density: 1.36E+04 cells/mL
- Control end cells density: 108.04E+04 cells/mL (mean of 6 replicates; SD 6.10E+04 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
- Culture medium different from test medium: no
- Intervals of water quality measurement: pH 0 and 72 h; temperature 0, 24, 48, and 72 h

OTHER TEST CONDITIONS
- Light intensity and quality: approx. 8000 lx; continuos universal white-type fluorescent light (400-700 nm)

EFFECT PARAMETERS MEASURED (with observation intervals if applicable)
- Determination of cell concentrations: [counting chamber; electronic particle counter; fluorimeter; spectrophotometer; colorimeter] direct counting with microscopic cell count using a Neubauer counting chamber

TEST CONCENTRATIONS
- Range finding study
- Results used to determine the conditions for the definitive study: no effects up to the highest test concentration

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

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.:

>= 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

>= 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Details on results:

- There was no statistically significant difference in growth rate between the control and the test group
- Exponential growth in the control (for algal test): yes
- validity criterion: was fulfilled

Description of key information

ErC50 (72h) > 100 mg/L (Desmodesmus subspicatus, OECD 201)
NOErC (72h) >= 100 mg/L (Desmodesmus subspicatus, OECD 201)

Additional information

One study on algal toxicity is available for Zinc aluminium oxide. This key study was performed as a limit test according to OECD Guideline 201, in a static system, using Desmodesmus subspicatus as test organism (2005). The test solutions were prepared by direct addition of the test substance without subsequent filtration. The algae were exposed to a nominal concentration of 100 mg/L for 72 hours. Since there was no statistically significant difference in growth rate between the control and treatment groups, the NOEC was determined to be >= 100 mg/L and EC50 > 100 mg/L.