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:
key study
Reliability:
1 (reliable without restriction)

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2015
Report Date:
2015

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
EU Method C.4-E (Determination of the "Ready" Biodegradability - Closed Bottle Test)
Qualifier:
according to
Guideline:
OECD Guideline 301 D (Ready Biodegradability: Closed Bottle Test)
Qualifier:
according to
Guideline:
EPA OPPTS 835.3110 (Ready Biodegradability)
GLP compliance:
yes (incl. certificate)

Test material

Reference
Name:
Unnamed
Type:
Constituent
Type:
Constituent

Study design

Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge, domestic, non-adapted
Duration of test (contact time):
28 d
Initial test substance concentration
Initial conc.:
3.5 mg/L
Based on:
test mat.

Results and discussion

% Degradationopen allclose all
Parameter:
% degradation (O2 consumption)
Value:
1.8
Sampling time:
7 d
Parameter:
% degradation (O2 consumption)
Value:
13.9
Sampling time:
14 d
Parameter:
% degradation (O2 consumption)
Value:
13.2
Sampling time:
21 d
Parameter:
% degradation (O2 consumption)
Value:
15.1
Sampling time:
28 d

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Interpretation of results:
other: not ready biodegradable
Conclusions:
the test item is not ready biodegradable
Executive summary:

The test item was exposed to activated sludge from the aeration tank of a domestic waste water treatment plant. The biodegradation was followed by the oxygen uptake of the microorganisms during exposure. As a reference item Sodium benzoate (at a concentration of 3.0 mg/L) was tested simultaneously under the same conditions as the test item, and functioned as a procedure control (reference control). Additionally inoculum (containing the filtered inoculum, only) and toxicity (containing both the test item and reference item) controls were examined.

The chosen test item concentration of 3.5 mg/L investigated in the main test was based on the results of the preliminary toxicity test, and based on the calculated theoretical oxygen demand of 1.48 mg O2/ mg of the test item.

Under the test conditions ready biodegradation of this test item was not noticed, the percentage biodegradation of MORIN reached a mean of 15.1 % after 28 days based on its ThOD.

The reference item Sodium benzoate was sufficiently degraded to a mean of 72.4 % after 14 days, and to a mean of 74.5% after 28 days of incubation, based on ThOD, thus confirming the suitability of the used activated sludge inoculum.

In the toxicity control containing both, the test item and the reference item, a mean of 40.2 % biodegradation was noted within 14 days and 44.2 % biodegradation after 28 days of incubation. Thus, the test item can be assumed to not inhibit the activated sludge microorganisms (higher than 25 % degradation occurred within 14 days).