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)
Rationale for reliability incl. deficiencies:
other: GLP guideline study with analytical monitoring

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1996
Report Date:
1996

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 301 C (Ready Biodegradability: Modified MITI Test (I))
GLP compliance:
yes

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): 625 Triketone
- Physical state: yellowish solid
- Analytical purity: 94%
- Batch No.: LJ 27881/1

Study design

Oxygen conditions:
aerobic
Inoculum or test system:
mixture of sewage, soil and natural water
Details on inoculum:
- Source of inoculum/activated sludge: Activated sludge micro-organisms have been selected following recommendations in OECD guideline 301C. The sludge was prepared from 10 different sampling sites throughout federal state Rheinland-Pfalz, Germany:
- Domestic sewage plants of Bad-Dürkheim, Lambsheim and Weisenheim, Germany
- Industrial sewage plant of BASF
- River water samples of River Rhine near Altrip and of a river near Kleiniedesheim
- Lake water samples of lake "Große Blies" near Ludwigshafen, of lake "Silbersee" near Roxheim, of a pond near Bad-Dürkheim and of a pond near Labsheim
- Method of sampling: 1 L of activated sludge was taken from the aeration basins of each waste water treatment plant; 1 L of surface water and 1 L of aerobic soil of the banks were taken in the case of rivers and lakes
- Preparation of inoculum for exposure: Collected samples were thoroughly mixed and allowed to settle for 30 min. Floating matter was removed. About 1.7 L of the mixture were filtered. 1.5 L of the filtrate were mixed with 1.5 L filtered supernatant of the existing culture. The mixtrue was kept on a temperature range of 25 ± 2 °C and a pH range of 7.0 ± 1.0 °C.
- Concentration of sludge: 30 mg/L dry solids

Duration of test (contact time):
28 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 SYSTEM
- Culturing apparatus: Sapromat BOD Apparatus – respirometer with a manometric coulorimetric principle. In a closed system oxygen consuption was automatically re-added by an electrolytic oxygen generator. The produced oxygen is monitored in mg/L and these BOD values are continuously stored. Carbon dioxide produced was adsorbed using soda lime pellets. Agitation of the solution was brought about by rotary stirring
- Vessels: 500 ml glass bottles
- Preparation of test assays: Determination of the suspended solids level of the activated sludge culture was carried out using 50 ml of the activated sludge culture which were carried after filtration on a filter paper until constant weight. The suspended solids concentration of the prepared activated sludge suspension was 750 mg ss/L. 10 ml of this suspension was added to each test vessel with 240 ml test medium resulting in a suspended solids loading of 30 mg ss/L
- Light regime: The cultures were shielded from light
- Number of culture flasks/concentration: 3

SAMPLING
- Sampling frequency: daily

CONTROL AND BLANK SYSTEM
- Inoculum blank: 1
- Reference substance: 1
- Abiotic control: 1
Reference substance
Reference substance:
aniline

Results and discussion

% Degradation
Parameter:
% degradation (O2 consumption)
Value:
25
Sampling time:
28 d
Details on results:
Mean degradation kinetic [%]:
Day 7: 4
Day 14: 19
Day 21: 23
Day 28: 25

Day 28 residual test material analysis (mean): 93%

Specific chemical analysis
Blank test with water: 71.3 mg/L (residual amount of test substance at end of test)
Inoculated medium: < 0.5 mg/L (residual amount of test substance at end of test)
Primary degradation (inoculated medium): 93%

BOD5 / COD results

Results with reference substance:
Concentration of aniline at start of the test: 95 mg/L (residual amount of test substance at end of test)
Concentration of aniline at the end of the test: < 0.1 mg/L (residual amount of test substance at end of test)
Primary degradation: 99%

Applicant's summary and conclusion

Interpretation of results:
other: moderately biodegradable