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Environmental fate & pathways

Biodegradation in water: screening tests

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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

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2010

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 301 B (Ready Biodegradability: CO2 Evolution Test)
GLP compliance:
yes (incl. certificate)

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): Maleic acid
- Physical state: solid
- Analytical purity: 99.7%

Study design

Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge, domestic, non-adapted
Details on inoculum:
- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure): Community Sewerage Plant Bharath Electronics Limted, Vidyaranyapuram, Bangalore, INDIA
- Laboratory culture: The effluent was allowed to settle for one hour and decanted. The decanted effluent was then used in the test
- Method of cultivation: The bacterial population in the inoculum was determined as colony forming units (CFU/mL) by diluting the inoculum up to 10-4 dilution and then plating on nutrient agar plates
Duration of test (contact time):
29 d
Initial test substance concentration
Initial conc.:
33.33 mg/L
Based on:
test mat.
Parameter followed for biodegradation estimation
Parameter followed for biodegradation estimation:
CO2 evolution
Details on study design:
TEST CONDITIONS
- Composition of medium: as described in the guideline

TEST SYSTEM
- Culturing apparatus: Conical flasks – 5 L capacity each fitted with an aeration tube reaching nearly to the bottom of the flask and an outlet
- Number of culture flasks/concentration: 4
- Method used to create aerobic conditions: continous gas flow
- Details of trap for CO2 and volatile organics if used: The amount of CO2 produced was calculated from the amount of base remaining in the absorption bottle. When 0.0125 M Ba(OH)2 was used as the absorbent, the amount remaining is assessed by titrating with 0.05 M HCl (thus, 50 mL HCl would be needed to titrate 100 mL Ba(OH)2).

SAMPLING
- Sampling frequency: every 3-4 days

CONTROL AND BLANK SYSTEM
- Inoculum blank: yes
- Toxicity control: yes
- Other: inhibition control

Reference substance
Reference substance:
benzoic acid, sodium salt

Results and discussion

% Degradation
Parameter:
% degradation (CO2 evolution)
Value:
> 90
Sampling time:
25 d
Remarks on result:
other: 10-day window reached

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Interpretation of results:
readily biodegradable