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
Study period:
2002-07-15 to 2002-09-26
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: The study was conducted according to the appropriate OECD test guideline, and in compliance with GLP.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2002
Report Date:
2002

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
OECD Guideline 301 F (Ready Biodegradability: Manometric Respirometry Test)
Version / remarks:
1992
Qualifier:
according to
Guideline:
EU Method C.4-D (Determination of the "Ready" Biodegradability - Manometric Respirometry Test)
GLP compliance:
yes (incl. certificate)

Test material

Reference
Name:
Unnamed
Type:
Constituent

Study design

Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge, domestic (adaptation not specified)
Details on inoculum:
- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure): domestic waste water treatment plant (Gross-Zimmern, Germany).

- Preparation of inoculum for exposure:
The activated sludge used for this study was washed by centrifugation and the supematant liquid phase was decanted. The solid material was resuspended in tap water and again centrifuged. This procedure was repeated twice. An aliquot of the final sludge suspension was weighed, dried and the ratio of wet sludge to its dry weight was determined. Based on this ratio, calculated aliquots of washed sludge suspension, corresponding to 1.5 g dry material per litre were mixed with test water and then aerated until use.
Duration of test (contact time):
28 d
Initial test substance concentrationopen allclose all
Initial conc.:
102 mg/L
Based on:
test mat.
Initial conc.:
105 mg/L
Based on:
test mat.
Parameter followed for biodegradation estimation
Parameter followed for biodegradation estimation:
O2 consumption
Details on study design:
TEST CONDITIONS

- Composition of medium: See below

- Test temperature: 21 - 22 *c

- pH: 7.6 (measured at the start of the test)

- Suspended solids concentration: 30mg/l activated sludge

- Continuous darkness: yes

TEST SYSTEM

- Culturing apparatus: Climatic chamber

- Number of culture flasks / concentration: 2

- Measuring equipment: The change of pressure in the test flasks was measured by means of a manometric method (BSB/BOD-Sensor-System,
Aqualytic, D-63263 Neu Isenburg, Germany) each day.

- Details of trap for CO2 and volatile organics if used: 45 % potassium hydroxide (aqueous)

SAMPLING

- Sampling frequency: daily

- Sampling method: Oxygen consumption measured automatically by respirometer

- Sample storage before analysis: none

CONTROL AND BLANK SYSTEM

- Inoculum blank: yes

- Abiotic sterile control: yes

- Toxicity control: yes
Reference substance
Reference substance:
aniline

Results and discussion

% Degradationopen allclose all
Parameter:
% degradation (O2 consumption)
Value:
30
Sampling time:
28 d
Remarks on result:
other: based on ThODNH4
Parameter:
% degradation (O2 consumption)
Value:
33
Sampling time:
28 d
Remarks on result:
other: based on ThODNH4
Details on results:
The oxygen demand of the inoculum control was 30 mg O2/L. This fulfills the validity criteria of the guideline (<60 mg O2/L within 28 days).

The reference item Aniline was sufficiently degraded to 82 % after 14 days, and to 94 % after 28 days of incubation, based on ThODNH4. The percentage biodegradation of the reference item confirms the suitability of the used activated sludge inoculum

In the toxicity control containing both, the test item and the reference item Aniline, 67 % biodegradation was noted within 14 days and 68 % biodegradation was determined after 28 days of incubation, if the calculation is based on ThODNH4. According to the test guidelines the test item can be assumed to be not inhibitory on the activated sludge micro organisms because degradation was> 25 % within 14 days.

In the abiotic control nearly the same oxygen demand was determined as in the controls.

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Interpretation of results:
other: not readily biodegradable
Conclusions:
A biodegradation rate of 30% to 33% in 28 days was determined in a reliable study conducted according to an appropriate test protocol, and in compliance with GLP.