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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 according to OECD criteria.
Cross-reference
Reason / purpose:
reference to same study
Reference
Endpoint:
biodegradation in water: ready biodegradability
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: GLP-Guideline study according to OECD criteria.
Justification for type of information:
See read-across justification attached in section 13.2
Reason / purpose:
read-across source
Related information:
Composition 1
Reference:
Composition 0
Qualifier:
according to
Guideline:
OECD Guideline 301 B (Ready Biodegradability: CO2 Evolution Test)
Deviations:
no
GLP compliance:
yes (incl. certificate)
Test material information:
Composition 1
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): Municipal activated sludge from the wastewater treatment plant of Mannheim, Germany. The inoculum was collected on 25 May 2012 from the aeration tank of the plant and aerated in the laboratory until use
- Method of cultivation: 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 96 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.
- Concentration of sludge: 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 conc.:
27 mg/L
Based on:
other: 20 mg/L TOC
Details on study design:
TEST CONDITIONS
- Composition of medium: According to guideline
- Test temperature: 22 ± 2° C
- pH: 7.4 ± 0.2
- pH adjusted: yes

TEST SYSTEM
-Vessels: 2 L incubation bottles filled up to a volume of 1.5 L.
- Number of culture flasks/concentration: 2
- Details of trap for CO2: 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 2, 6, 8,14, 17, 20, 24, 27, 28 and day 29
- Sample storage before analysis: The samples were analyzed on the day of sampling

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


Reference substance:
aniline
Parameter:
% degradation (CO2 evolution)
Value:
70 - 80
Sampling time:
28 d
Results with reference substance:
Degree of biodegradation of the reference substance after 14 days: 61 % CO2/ThCO2
Validity criteria fulfilled:
yes
Interpretation of results:
readily biodegradable, but failing 10-day window

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)
Deviations:
no
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): Tetrahydrogeraniol
- Physical state: Liquid, colorless / clear
- Analytical purity: 98.3 corr. area % (BASF report No. 11L00269)
- Lot/batch No.: Ch. 65872377L0
- Expiration date of the lot/batch: 04 July 2012
- Stability under test conditions: stable
- Storage condition of test material: Storage at room temperature under exclusion of light
- Water solubility: insoluble

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): Municipal activated sludge from the wastewater treatment plant of Mannheim, Germany. The inoculum was collected on 25 May 2012 from the aeration tank of the plant and aerated in the laboratory until use
- Method of cultivation: 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 96 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.
- Concentration of sludge: 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 concentration
Initial conc.:
27 mg/L
Based on:
other: 20 mg/L TOC
Details on study design:
TEST CONDITIONS
- Composition of medium: According to guideline
- Test temperature: 22 ± 2° C
- pH: 7.4 ± 0.2
- pH adjusted: yes

TEST SYSTEM
-Vessels: 2 L incubation bottles filled up to a volume of 1.5 L.
- Number of culture flasks/concentration: 2
- Details of trap for CO2: 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 2, 6, 8,14, 17, 20, 24, 27, 28 and day 29
- Sample storage before analysis: The samples were analyzed on the day of sampling

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


Reference substance
Reference substance:
aniline

Results and discussion

% Degradation
Parameter:
% degradation (CO2 evolution)
Value:
70 - 80
Sampling time:
28 d

BOD5 / COD results

Results with reference substance:
Degree of biodegradation of the reference substance after 14 days: 61 % CO2/ThCO2

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Interpretation of results:
readily biodegradable, but failing 10-day window