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Environmental fate & pathways

Biodegradation in water: screening tests

Administrative data

Endpoint:
biodegradation in water: ready biodegradability
Type of information:
experimental study
Adequacy of study:
key study
Study period:
13 May - 24 Jun, 1999
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: done under OECD method and GLP

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1999
Report Date:
1999

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
OECD Guideline 301 D (Ready Biodegradability: Closed Bottle Test)
Qualifier:
according to
Guideline:
EU Method C.4-E (Determination of the "Ready" Biodegradability - Closed Bottle Test)
GLP compliance:
yes

Test material

Reference
Name:
Unnamed
Type:
Constituent

Study design

Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge (adaptation not specified)
Details on inoculum:
Effluent from a strongly aerated laboratory activated sludge plant was kept under aerobic conditions. To prepare the inoculum, the sample was filtered through a course filter and the first 200ml discarded.
Duration of test (contact time):
28 d
Parameter followed for biodegradation estimation
Parameter followed for biodegradation estimation:
O2 consumption
Details on study design:
Inhibition effects, if any, were checked by testing together the test article (2mg/L) and the reference substance, sodium acetate (2mg/L)

Test solns were incubated in the dark at 20±1°C and analysed for dissolved oxygen at 7, 14, 21 and 28 days.
Reference substance
Reference substance:
other: sodium acetate

Results and discussion

Preliminary study:
A-164220.0 can not be considered readily biodegadeable.
There was no evidence of inhibitory effects on the bacteria inoculum at 2mg/L.
% Degradationopen allclose all
Parameter:
% degradation (O2 consumption)
Value:
0
Sampling time:
7 d
Parameter:
% degradation (O2 consumption)
Value:
0.63
Sampling time:
14 d
Parameter:
% degradation (O2 consumption)
Value:
1.58
Sampling time:
21 d
Parameter:
% degradation (O2 consumption)
Value:
0.32
Sampling time:
28 d
Details on results:
Since the biodegradation in the 2 series of bottles containing 2mg/L sodium acetate + 2mg/L A-172245.0 on day 14 was 78.2% (i.e. greater than 25% of the ThOD), it can be assumed that the test article has no significant inhibitory effect on the bacteria inoculum.
Since the biodegadability of the test article did not exceed the pass level of 60%, determinations for nitrites and nitrates were not performed.

BOD5 / COD results

Results with reference substance:
Sodium acetate attained 57.7%, 73.7%, 75.6% and 80.1% biodegredation after 7, 14, 21 and 28 days respectively.

Any other information on results incl. tables

COD: 1.579 O2/mg (average value)

ThOD NH3 (without nitrification): 1.598 O2/mg

ThOD of the reference substance: 0.780 O2/mg

BOD on days 7,14, 21 and 28 were 0, 0.01, 0.025 and 0.005 mg O2/mg

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Interpretation of results:
other: not readily biodegradable
Conclusions:
COD: 1.579 O2/mg (average value)
ThOD NH3 (without nitrification): 1.598 O2/mg
ThOD of the reference substance: 0.780 O2/mg
BOD on days 7,14, 21 and 28 were 0, 0.01, 0.025 and 0.005 mg O2/mg
Executive summary:

A-164220.0 can not be considered readily biodegadeable.

There was no evidence of inhibitory effects on the bacteria inoculum at 2mg/L.