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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
Study period:
2012-04-02 to 2012-04-30 (experimental phase)
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: GLP guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2012
Report Date:
2012

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
Test material form:
other: White solid

Study design

Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge, domestic, non-adapted
Details on inoculum:
- Source of inoculum: Municipal activated sludge from the wastewater treatment plant of Mannheim, Germany.
- Storage conditions: aerated in the laboratory until use
- Pretreatment: A suitable aliquot of the activated sludge suspension was sieved by a finely woven mesh with a mesh size about 1 mm. To reduce the content
of inorganic carbon in the blank controls the activated sludge was aerated with carbon dioxide free air for about 72 hours at 22 ± 2° C. At the day of exposure the suspension was washed one time with drinking water. Therefore the aeration was stopped and the sludge was allowed to settle. After settling the supernatant was discarded and the remaining sludge suspension was filled up with drinking water and the concentration oft the sludge was adjusted to 6.0 g/L dry weight. Aliquots of 7.5 mL were added to the test vessels to obtain an activated sludge concentration of 30 mg/L dry weight.
Duration of test (contact time):
28 d
Initial test substance concentrationopen allclose all
Initial conc.:
20 mg/L
Based on:
other: TOC
Initial conc.:
27 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: According to guideline
- Test temperature: 22 ± 2°C
- pH: 7.3 - 7.4
- Suspended solids concentration: 6 g/L
- Aeration of dilution water: yes

TEST SYSTEM
- Culturing apparatus: 2 L incubation bottles, fill volume of 1.5 L
- Number of culture flasks/concentration: 2
- Details of trap for CO2 and volatile organics if used: The bottles were connected to two serial scrubbing bottles (total volume 250 mL) filled with 100 mL 0.05 mol sodium hydroxide solution for the adsorption of carbon dioxide from biodegradation processes. Usually twice a week the Total Inorganic Carbon (TIC) values of the adsorption solutions of the first trap were determined and used for the calculation of the produced carbon dioxide. After each sampling the second trap was moved forward and the new trap with fresh sodium hydroxide solution was placed into the second position. Each trap was analyzed separately.

SAMPLING
- Sampling frequency: On days 0, 2, 8, 10, 14, 18, 21, 23, 25, 28, 30

CONTROL AND BLANK SYSTEM
- Inoculum blank: 2
- Toxicity control: 1
Reference substance
Reference substance:
aniline

Results and discussion

% Degradation
Parameter:
% degradation (CO2 evolution)
Value:
< 10
Sampling time:
28 d

BOD5 / COD results

Results with reference substance:
Degree of biodegradation of the reference substance after 14 days: 81 % CO2/ThCO2

Any other information on results incl. tables

Degree of biodegradation in the inhibition control after 14 days: 41 % CO2/ThCO2

Applicant's summary and conclusion

Interpretation of results:
other: poorly biodegradable