Hexakis[μ-(acetato-O:O')]-μ3-oxo-triangulo-triruthenium acetate

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

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Deviations:

not specified

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

Water samples taken from control and test vessels at 0 and 72 hours.

Vehicle:

not specified

Details on test solutions:

Preliminary range-finding study conducted at 0.10, 1.0, 10 and 100mg/L.
Definitive study conducted at concentrations of 0.1, 0.2, 0.4, 0.8 and 1.6 mg/L. Test solutions were prepared by dissolving test material directly in the culture medium with the aid of ultrasonication to produce the stock solution. This was then diluted to prepare the test concentrations.

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

Obtained from the Culture Collection of Algae and Protozoa, UK. Maintained in the laboratory at a temperature of 21±1°C under continuous illumination and constant aeration.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Test temperature:

24±1°C

pH:

Increases in pH due to carbon dioxide demand

Dissolved oxygen:

No data

Salinity:

Not applicable

Nominal and measured concentrations:

Nominal concentrations: 0.10, 0.20, 0.40, 0.80 and 1.6 mg/L
Chemical analysis in the samples at 0 hours were 79 to 96% of nominal and at 72 hours were 35 to 58% of nominal.
EC50 values were reported based on time-weighted mean measured concentrations.

Details on test conditions:

Test vessel: 250ml conical flasks used
Initial cell density: At initiation the culture contained a nominal cell density of 104 cells per ml
No of replicates per concentration: Three flasks prepared for the control and each treatment group
Photoperiod: Continuous illumination

Reference substance (positive control):

not specified

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 1.6 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

0.94 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

0.1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

0.59 mg/L

Nominal / measured:

meas. (TWA)

Conc. based on:

test mat.

Basis for effect:

biomass

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 0.97 mg/L

Nominal / measured:

meas. (TWA)

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

0.063 mg/L

Nominal / measured:

meas. (TWA)

Conc. based on:

test mat.

Basis for effect:

growth rate

Details on results:

Time weighted mean measured test concentrations used. Loss of test material is thought to be due to adsorbtion to the algal cells or the presence of algal cells interferring with the method of analysis

Reported statistics and error estimates:

Statistical analysis performed using the SAS computer software package.

Cell concentration in the control cultures increased by a factor of 87

Conclusions:

The 72-hour EbC50 was 0.59 mg/L and the ErC50 was >0.97 mg/L. The NOEC was 0.063 mg/L, all based on time-weighted averages.

Executive summary:

This study is GLP compliant and follows OECD guideline 203. Measured test concentrations declined during the study, therefore effect concentrations were based on time-weighted averages. The study is considered to be reliable and suitable for use as the key study for this endpoint. The 72-hour EbC50 was 0.59 mg/L and the ErC50 was >0.97 mg/L. The NOEC was 0.063 mg/L, all based on time-weighted averages.

Description of key information

The 72-hour EbC50 was 0.59 mg/L and the ErC50 was >0.97 mg/L. The NOEC was 0.063 mg/L, all based on time-weighted averages.

Key value for chemical safety assessment

EC50 for freshwater algae:

0.59 mg/L

EC10 or NOEC for freshwater algae:

0.063 mg/L

Additional information

Mead and Mullee (2001) is GLP compliant and follows OECD guideline 203. Measured test concentrations declined during the study, therefore effect concentrations were based on time-weighted averages. The study is considered to be reliable and suitable for use as the key study for this endpoint. The 72-hour EbC50 was 0.59 mg/L and the ErC50 was >0.97 mg/L. The NOEC was 0.063 mg/L, all based on time-weighted averages.