Registration Dossier

Environmental fate & pathways

Biodegradation in water: screening tests

Administrative data

Endpoint:
biodegradation in water: ready biodegradability
Type of information:
experimental study
Adequacy of study:
supporting study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2003

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 301 B (Ready Biodegradability: CO2 Evolution Test)
GLP compliance:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
liquid: viscous

Study design

Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge, non-adapted
Details on inoculum:
Inoculum: Activated sludge from sewage treatment plant Frankfurt-Niederrad; 300 mg centrifuged activated sludge/l

Pre-treatment: The activated sludge was aerated for I day and washed three times with mineral medium
Duration of test (contact time):
28 d
Initial test substance concentration
Initial conc.:
>= 33.2 - <= 33.7 mg/L
Based on:
test mat.
Parameter followed for biodegradation estimation
Parameter followed for biodegradation estimation:
CO2 evolution
Details on study design:
Test medium: Mineral medium according to OECD 301 B

Test vessel: Brown glass bottles, 5 I volume with ground glass neck, each fitted with an aeration tube and an outlet

Test volume: 3l

Temperature: 22± 2 °C

Agitation: Magnetic stirrer

Analytical method: CO2 measurement

Test duration: 28 days
Reference substance
Reference substance:
benzoic acid, sodium salt

Results and discussion

% Degradation
Parameter:
% degradation (CO2 evolution)
Value:
>= 28 - <= 37
Sampling time:
28 d

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Interpretation of results:
not readily biodegradable
Conclusions:
The substance is not readily biodegradable according to OECD301B study.
Executive summary:

The ready biodegradability of the test substance was tested in the CO2 Evolution Test with non-adapted inoculum over a period of 28 days according to OECD Guideline for Testing of Chemicals 301 B.

The test substance in the concentration of 33 mg/1 reached a degree of degradation of 28% resp. 37% after 28 days. The level of 10% degradation (begin of biodegradation) was reached after 8 days. The 60% level was not reached within 28 days. The test substance is not readily biodegradable.

In order to check the validity of the test sodium benzoate in a concentration of 21 mg/1 was used as reference substance. The pass level of 60 % degradation within 14 days was reached.

A toxicity test, containing both the test substance and the reference substance, was not run because the test substance was assumed to be not inhibitory.

The validity criteria according to the guideline were fulfilled in the test.