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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:
21.03.1997 - 25.04.1997
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
guideline study without detailed documentation

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1997
Report date:
1997

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to guideline
Guideline:
OECD Guideline 301 F (Ready Biodegradability: Manometric Respirometry Test)
Qualifier:
according to guideline
Guideline:
ISO DIS 9408 (Ultimate Aerobic Biodegradability - Method by Determining the Oxygen Demand in a Closed Respirometer)
GLP compliance:
yes
Remarks:
BASF AG, Ökologie und Umweltanalytik, Labor für Mikrobiologie, 67056 Ludwigshafen (Germany)

Test material

Constituent 1
Chemical structure
Reference substance name:
3,7-dimethyloctane-1,7-diol
EC Number:
203-517-1
EC Name:
3,7-dimethyloctane-1,7-diol
Cas Number:
107-74-4
Molecular formula:
C10H22O2
IUPAC Name:
3,7-dimethyloctane-1,7-diol
Test material form:
liquid

Study design

Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge, non-adapted
Details on inoculum:
- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure): BASF laboratory stp
- Laboratory culture: yes
- Method of cultivation:
- Storage conditions:
- Storage length:
- Preparation of inoculum for exposure:
- Pretreatment:
- Concentration of sludge: 30 mg/L dry matter
Duration of test (contact time):
35 d
Initial test substance concentration
Initial conc.:
100 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: acc. to guideline
- Additional substrate: no
- Solubilising agent (type and concentration if used): no
- Test temperature: room temperature (not further specified)
- pH: initial: 7.3-7.4; at test end: 7.5-9.0
- pH adjusted: no

TEST SYSTEM
- Culturing apparatus: Sapromat
- Number of culture flasks/concentration: 7
- Method used to create aerobic conditions: not reported
- Measuring equipment: Sapromat
- Test performed in closed vessels: yes

SAMPLING
- Sampling frequency: continuosly during the test
- Sample storage before analysis: no

CONTROL AND BLANK SYSTEM
- Inoculum blank: performed
- Abiotic sterile control: performed
- Toxicity control: performed
- other: the biodegradation of the procedural control (aniline) was measured
Reference substance
Reference substance:
aniline

Results and discussion

% Degradationopen allclose all
Key result
Parameter:
% degradation (O2 consumption)
Value:
70 - 80
Sampling time:
28 d
Key result
Parameter:
% degradation (O2 consumption)
Value:
80 - 90
Sampling time:
35 d

BOD5 / COD results

BOD5 / COD
Parameter:
ThOD
Value:
2 609 mg O2/g test mat.
Results with reference substance:
Aniline was biodegraded by 70-80% within 14 d.

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Interpretation of results:
readily biodegradable
Conclusions:
The test item proved to be readily biodegradable and fulfilling the 10-d-window criterion (70 -80% biodegradation after 28 d and 80 -90% biodegradation after 35 d of incubation at a test substance concentration of 100 mg/L). The test duration was prolonged to 35 d as the biodegradation did not reach a plateau after 28 d. The functional control reached the pass level > 60% after 14 d. In the toxicity control containing both test and reference item 78% biodegradation based on oxygen consumption occurred within 14 d thus indicating that the test item was not inhibitory at the concentration tested.
Executive summary:

The ready biodegradation of the hydroxyciol (hydroxycitronellol) was investigated in a study conducted according to OECD Guideline 301 F (Ready Biodegradability: Manometric Respirometry Test) and ISO DIS 9408 (Ultimate Aerobic Biodegradability-Method by Determining the Oxygen Demand in a Closed Respirometer) over a period of 28/35 days and using activated sludge as inoculum collected from a laboratory sewage treatment plant which is fed with municipal and synthetic wastewater. The biodegradation rate was determined by measurement of oxygen consumption. Inoculum blank, procedural/functional control with the reference substance aniline, and toxicity control were performed.

 

This study is regarded as reliable without restrictions and satisfies the guideline requirements for ready biodegradation.

The test item proved to be readily biodegradable and fulfilling the 10-d-window criterion (70 -80% biodegradation after 28 d and 80 -90% biodegradation after 35 d of incubation at a test substance concentration of 100 mg/L). The test duration was prolonged to 35 d as the biodegradation did not reach a plateau after 28 d. The functional control reached the pass level > 60% after 14 d. In the toxicity control containing both test and reference item 78% biodegradation based on oxygen consumption occurred within 14 d thus indicating that the test item was not inhibitory at the concentration tested.