PIGMENT RED 5021B

Toxicity to microorganisms

Administrative data

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1991-06-17 to 1991-06-26

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: OECD guideline, GLP study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1991

Report date:

1991

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test

Deviations:

yes

Principles of method if other than guideline:

Instead of a centrifuged sludge a settled sludge was used. Due to the poor solubility of the test substance at test concentrations, no stock solution was prepared. The test substance was given directly into the medium.

GLP compliance:

yes

Test material

Test material information

Constituent 1

Test organisms

Test organisms (species):

activated sludge

Details on inoculum:

- Activated sludge collected from the sewage treatment plant of CH-4153 Reinach on 24/06/91. The preparation was carried out according to the method described in the guideline. The sludge was separated from the aqueous layer by settling instead of centrifugation.

Study design

Water media type:

freshwater

Limit test:

no

Total exposure duration:

3 h

Test conditions

Nominal and measured concentrations:

nominal: 98.7, 31.75, 11.85, 4.35 and 1.8 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: 250 ml BOD flasks with gas inlet
- Aeration: yes
- Temperature: 20 +/-2°C

TEST MEDIUM / WATER PARAMETERS
- Nutrient solution was prepared according to the guideline

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :

TEST CONCENTRATIONS
98.7, 31.75, 11.85, 4.35 and 1.8 mg/L
19.74, 6.35, 2.37, 0.87 and 0.36 mg of the test substance were weighed and added to the test medium. The volume was adjusted to 200 mL with water and aerated for 3 hours.
Reference substance : 32, 10 and 3.2 mg/L
The sludge concentration in the test bottles was 1.6 g/L (dry weight).

Reference substance (positive control):

yes

Remarks:

3,5-Dichlorophenol

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

3 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Effect concentrations 2

Duration:

3 h

Dose descriptor:

other: EC20

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Effect concentrations 3

Duration:

3 h

Dose descriptor:

other: EC80

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Results with reference substance (positive control):

EC50 (3h) = 16.4 mg/L

Reported statistics and error estimates:

The inhibitions were calculated on the basis of the measured time depend oxygen consumption of a Blank and Test solution.