Formaldehyde, reaction products with 5,12-dihydroquino[2,3-b]acridine-7,14-dione and 3,5-dimethyl-1H-pyrazole, sulfonated

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:

1992-01-14 to 1992-02-11

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Study performed under GLP according to OECD guideline 301 B (adopted 1981)

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1992

Report date:

1992

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 B (Ready Biodegradability: CO2 Evolution Test)

Version / remarks:

adopted 12 May 1981

Deviations:

no

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 13/01/92; pH 7.7
- Preparation of inoculum for exposure: according to guideline

Duration of test (contact time):

28 d

Initial test substance concentration

Initial test substance concentration 1

Initial conc.:

10.5 mg/L

Based on:

test mat.

Initial test substance concentration 2

Initial conc.:

21.3 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation

Parameter followed for biodegradation estimation:

CO2 evolution

Details on study design:

TEST CONDITIONS
- Composition of medium: according to guideline
- Solubilising agent: emulsifier: Polyoxyethylen-Sorbitan-Monooleate (TWEEN 80); 15 mL of emulsifier solution (30 mg emulsifier in 100 mL bidist. water) add 300 mL water plus test substance
- Test temperature: Temperature : 22 + 2°C
- pH: 7.7 (inoculum)
- Aeration of dilution water: 25 mL air per min purified from carbon dioxide
- Continuous darkness: dark brown glass vessels only


TEST SYSTEM
- Number of culture flasks/concentration: Vessels: 2 Liter flasks (dark brown glass) equipped with gas inlet and magnetic stirrer.
- Method used to create aerobic conditions: 25 mL air per min purified from carbon dioxide; 24 hours aeration
- Measuring equipment: carbon analyzer
- Test performed in open system: flasks equipped with gas inlet
- Details of trap for CO2: CO2 was trapped in 200 ml 0.05 N sodium hydroxide

SAMPLING
- Sampling frequency: on day 0, 3, 6, 10, 13, 17, 21, 24, 27 and 28

CONTROL AND BLANK SYSTEM
- Inoculum blank: water with inoculum containing 3 mg/L TWEEN 80


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

% Degradation

Parameter:

% degradation (CO2 evolution)

Value:

0

Sampling time:

28 d

BOD5 / COD results

Results with reference substance:

After 13 days, the mean degradation rate for the reference substance was 78 %.
After 28 days, the mean degradation rate for the reference substance was 93 %.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Interpretation of results:

under test conditions no biodegradation observed