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Environmental fate & pathways

Biodegradation in water: screening tests

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Administrative data

Endpoint:
biodegradation in water: inherent biodegradability
Type of information:
migrated information: read-across based on grouping of substances (category approach)
Adequacy of study:
key study
Study period:
2012-03-07 to 2012-04-24
Reliability:
1 (reliable without restriction)

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 302 C (Inherent Biodegradability: Modified MITI Test (II))
Deviations:
yes
GLP compliance:
yes (incl. certificate)
Remarks:
GLP according to German Chemikaliengesetz and Directive 88/320/EEC

Test material

Reference
Name:
Unnamed
Type:
Constituent

Study design

Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge, non-adapted
Duration of test (contact time):
28 d
Initial test substance concentration
Initial conc.:
30 mg/L
Based on:
test mat.
Parameter followed for biodegradation estimation
Parameter followed for biodegradation estimation:
O2 consumption
Reference substance
Reference substance:
aniline

Results and discussion

Test performance:
Based on the calculated oxygen demand (ThOD), the test con-centration of 30 mg/L corresponding to an oxygen demand of
54.6 mgO2 /L in the vessel was selected.

The test solutions were prepared in measuring flasks and given into brown glass bottles as incubation vessels (inoculum control, functional control) or were prepared directly in brown glass
bottles (test item, blank):
• 3 incubation vessels for the test item (P1, P2, P3)
• 2 incubation vessels for the functional control (R1, R2)
• 1 incubation vessel for the blank (B1)
• 2 incubation vessels for the inoculum control (C1, C2)

Separate replicates for the test item and blank were prepared for pH measurement at test start:
• 1 incubation vessel for the test item (PpH)
• 1 incubation vessel for the blank (BpH)

The test item was weighed out and was transferred directly into the brown glass bottles with 250 mL test medium (consisting of the appropriate volumes of mineral medium stock solutions, de-mineralised water and inoculum) for the test item replicates and with 250 mL demineralised water for the blank, respectively.
% Degradation
Parameter:
% degradation (O2 consumption)
Value:
0
Sampling time:
28 d

BOD5 / COD results

Results with reference substance:
The adaptation phase changed to degradation phase after 4 days in both replicates. The functional control reached the pass level of > 65 % after 9 days in the 1st replicate and after 11 days in the 2nd replicate. The mean biodegradation rate on day 14 was 78 %. Hence the validity criterion that the degradation should be > 65 % after 14 days was fulfilled. It came to a biodegradation rate of 100 % after 28 days

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Interpretation of results:
not inherently biodegradable