PIGMENT RED 5021B

Biodegradation in water: screening tests

Administrative data

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1991-06-26 to 1991-08-22

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: OECD study, GLP

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 301 C (Ready Biodegradability: Modified MITI Test (I))

Deviations:

yes

Principles of method if other than guideline:

The volume of the test solution was reduced from 3.0 L to 1.5 L. The CO2 formed by biodegradation was absorbed with NaOH and determined on a carbon analyzer.

GLP compliance:

yes

Test material

Test material information

Constituent 1

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, non-adapted

Details on inoculum:

- Source of inoculum/activated sludge: Bacteria collected from activated sludge of the sewage treatment plant of CH-4153 Reinach on 24/06/91
- Preparation of inoculum for exposure: 1200 ml of the mineral solution with the inoculum were aerated for 24 hours in the test vessel. In 300 mL mineral solution 16.4 rsp. 30.1 mg of test substance were added and homogenized. This solution was given to the test vessel which was immediately connected to the CO2 traps.

Duration of test (contact time):

28 d

Initial test substance concentration

Initial test substance concentration 1

Initial conc.:

10.9 mg/L

Based on:

test mat.

Initial test substance concentration 2

Initial conc.:

20.1 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation

Parameter followed for biodegradation estimation:

CO2 evolution

Details on study design:

TEST CONDITIONS
- Test temperature: 22 + 2°C

TEST SYSTEM
- Test medium was prepared according to the guideline
- Vessles: 2 Liter flasks (dark brown glass) equipped with gas inlet and magnetic stirrer.
- Air: = 25 ml/min purified from carbon dioxide.

CONTROL AND BLANK SYSTEM
- Inoculum blank: Test medium with inoculum.

STATISTICAL METHODS:
The biodegradation was calculated on the basis of the theoretical carbon content of the test substance and the cumulative quantities of carbon dioxide determined on the days of measurements. For the calculation the formula given in the guideline was used.

Reference substance

Reference substance:

aniline

Results and discussion

Test performance:

Determination of the initial CO2 of the 0.05 N sodium hydroxide and the CO2, absorbed in the absorbers filled with 200 ml 0.05 N sodium hydroxide on the days 3, 6, 10, 13, 17, 20, 24, 27 and 28.

% Degradation

% Degradation 1

Parameter:

% degradation (CO2 evolution)

Value:

9

Sampling time:

28 d

Remarks on result:

other: 10.9 mg test substance/L

% Degradation 2

Parameter:

% degradation (CO2 evolution)

Value:

3

Sampling time:

28 d

Remarks on result:

other: 20.1 mg test substance/L

Details on results:

Theoretical carbon dioxide evolution
Test substance : 16.4 mg/1.5L = 30.86 mg CO2/1.5 liter.
Test substance : 30.1 mg/1.5L = 56.64 mg CO2/1.5 liter.
This calculation is based on carbon analysis.