PIGMENT RED 5021B

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:

08.07.2005 - 17.08.2005

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

OECD guideline study, GLP. The coefficient of analysis of the daily growth rate in the control replicates and the coefficient of analysis of the average specific growth rates in the control replicates were not reported according to the current guideline adapted 2006.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2005

Report date:

2005

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Version / remarks:

adopted 1984

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

- Sampling method: fourfold samples from each test medium and duplicate from the control, just before the start of the test and after 72 hours.
- Sample storage conditions before analysis: deep frozen (-20°C) immediately after sampling

Test solutions

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: WAF
Test media with following loading rates were preapred: 0.32, 1.0, 3.2, 10, 32 and 100 mg/L. Ultrasonic treatment was applied for 15 minutes and the dispersions were the strirred at room temperature in the dark for 96 hours. Thereafter, the dispersions were filtered through a membran filter with a pore size of 0.45 µm.

- Controls: test water without test substance

Test organisms

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

EST ORGANISM
- Common name: Scenedesmus subspicatus CHODAT
- Strain: No. 86.81 SAG
- Source: grown in RCC laboratories and obtained from Collection of Algal Cultures (SAG, Institute for Plant Physiology, University of Gottingen, D-37073 Gottingen, Germany).
- Age of inoculum (at test initiation): The test was started (0 hours) by inoculation of 10,000 algal cells per mL of test medium. The algal cells were taken from an exponentially growing pre-culture which was set up four days prior to the test under the same conditions as in the test. One day before the start of the test, the pre-culture was diluted threefold to keep the algae in exponential growth.
- Method of cultivation: cultivated and tested in synthetic test water, prepared according to the test guidelines.

ACCLIMATION
- Acclimation period: no
- Culturing media and conditions (same as test or not): same
- Any deformed or abnormal cells observed: no

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72

Test conditions

Hardness:

0.24 mmol/L (= 24 mg/L as CaCO3)

Test temperature:

between 22 °C and 23 °C

pH:

start: 7.9 to 8.1
end: 8.0 to 8.9

Dissolved oxygen:

Not determined.

Nominal and measured concentrations:

Nominal: WAF loading rate was 0.32, 1.0, 3.2, 10, 32 and 100 mg/L one control wizhout test substance
Nominal: based on Disulfo-DPP-Ca-salt the initial test concentrations were 0.068, 0.22, 0.47, 0.74 and 1.1 mg/L. The concentrations decreased to 17 - 34% of the initial measured concentrations during incubation period due to the irradiation.

Based on Monochloro-monosulfo-DPP-Ca-salt and Dichloro-DPP the initial concentrations were 0.019, 0.043, 0.18, 0.28 and 0.75 mg/L. The concentrations decreased to 37- 38% of the initial measured concentrations during incubation.

Details on test conditions:

TEST SYSTEM
- Test vessel: 50 mL Erlenmeyer flasks. The flasks were covered with glass dishes.
- Material, size, headspace, fill volume: 15 mL
- Aeration: no
- Initial cells density: 10,000 algal cells per mL test medium.
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 6

GROWTH MEDIUM
- Standard medium used: yes

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: The algae were cultivated and tested in synthetic test water.
- Culture medium different from test medium: no
- Intervals of water quality measurement: The pH was measured in each test concentration and the control at the start and end of the test. The water temperature was measured daily in an Erienmeyer flask filled with water and incubated under the same conditions as the test flasks. The appearance of the test media was recorded dally.

OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: continuously illuminated
- Light intensity and quality: about 8100 Lux; achieved with fluorescent tubes


EFFECT PARAMETERS MEASURED:
- Determination of cell concentrations: electronic particle counter
- Chlorophyll measurement: no
- Other: In addition, after 72 hours exposure, a sample was taken from the control and from the highest test concentration (undiluted filtrate). The shape of the algal cells was microscopically examined in these samples.

TEST CONCENTRATIONS
The test concentrations were based on the results of a range-finding test.

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

12.4 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Remarks on result:

other: 2.5 - 251

Effect concentrations 2

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 3

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Effect concentrations 4

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Details on results:

- Exponential growth in the control (for algal test): yes
- Observation of abnormalities (for algal test): no
- Unusual cell shape: not observed
- Colour differences: not observed
- Flocculation: not observed
- Adherence to test vessels: not observed
- Aggregation of algal cells: not observed

Results with reference substance (positive control):

For evaluation of the algal quality and experimental conditions, potassium dichromate is tested as a positive control at least once a year to demonstrate satisfactory conditions of the test.

Reported statistics and error estimates:

NOEC determined by Dunnett´s test and EC50 with probit analysis.