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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:
From June 13th to July 12th, 1996
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

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

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
OECD Guideline 301 D (Ready Biodegradability: Closed Bottle Test)
Version / remarks:
July 17th, 1992
Qualifier:
according to
Guideline:
EU Method C.4-E (Determination of the "Ready" Biodegradability - Closed Bottle Test)
Version / remarks:
December 1992
GLP compliance:
yes (incl. certificate)

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
solid

Study design

Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge, domestic (adaptation not specified)
Duration of test (contact time):
28 d
Initial test substance concentration
Initial conc.:
2.6 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:
The dissolved oxygen concentration showed a slight decrease from exposure day 0 to exposure day 4, resulting in a mean percentage biodegradation of 9.4 % within the first four exposure days. Thereafter, the BOD of test item gradually increased over the 28-day exposure period from 0.104 and 0.123 mg O2/mg test item on exposure day 4 to 0.165 and 0.188 mg O2/mg test item on exposure day 28. Expressed as percentage biodegradation, test item was biodegraded by an average of 11.1, 11.0 and 14.7 % on exposure days 7, 14 and 28, respectively.
% Degradation
Parameter:
other: BOD/ThOD_NH4 × 100 %
Value:
14.7
Sampling time:
28 d
Details on results:
Points of degradation plot (test substance):
9.4 % degradation after 4 d
11.1 % degradation after 7 d
12.1 % degradation after 11 d
11.0 % degradation after 14 d
8.2 % degradation after 21 d
14.7 % degradation after 28 d

BOD5 / COD results

Results with reference substance:
Points of degradation plot (reference substance):
67.6 % degradation after 4 d
71.7 % degradation after 7 d
81.5 % degradation after 11 d
74.8 % degradation after 14 d
100 % degradation after 21 d
100 % degradation after 28 d

Any other information on results incl. tables

The test substance was slightly biodegraded by an average of 11.1 % and 11.0 % after 7 and 14 days of exposure, respectively. At the end of the 28-day exposure period, the test substance was slightly biodegraded by an average of 14.7 %. Moreover, no nitrification was noted.

In the toxicity control, containing both the test substance and the reference compound aniline, no inhibitory effect on the microorganisms was observed. In the procedure control, the reference compound aniline was readily biodegraded by an average of 74.8 % within 14 days of exposure. At the end of the 28-day exposure period, aniline was completely biodegraded (100 %).

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Interpretation of results:
not readily biodegradable
Conclusions:
The test substance was found to be not readily biodegradable.