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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:
other information
Study period:
Feb 1999-March 1999
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: well documented GLP study

Data source

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

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 301 B (Ready Biodegradability: CO2 Evolution Test)
Deviations:
no
GLP compliance:
yes

Test material

Reference
Name:
Unnamed
Type:
Constituent

Study design

Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge, domestic, non-adapted
Duration of test (contact time):
28 d
Initial test substance concentration
Initial conc.:
10 mg/L
Based on:
DOC

Results and discussion

% Degradationopen allclose all
Parameter:
% degradation (CO2 evolution)
Value:
85
Sampling time:
28 d
Parameter:
% degradation (CO2 evolution)
Value:
68
Sampling time:
18 d
Parameter:
% degradation (CO2 evolution)
Value:
19
Sampling time:
7 d
Details on results:
The reference compound (sodium acetate was degraded to 71% at day 9 and 100 % at day 28.
The toxicity control showed degradation rates of 70 at day 14 and 93% at the end of incubation

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Interpretation of results:
readily biodegradable, but failing 10-day window
Conclusions:
Androstenolone acetate is rapidly biodegradable, but failed to meet the stringent criteria for ready biodegradability.
Executive summary:

The test substance was incubated with activated sludge originating from a municipal sewage treatment plant pimarily dealing with domestic sewage. The incubation period was 28 days. The test compound was introduced at a concentration of 10 mg/l as carbon Additionally, a reference substance (sodium acetate) was incubated and a toxicity control. CO2 produced was trapped by bariumhydroxide and sampled at day 3, 4, 7, 9, 14, 18, 23, 28 and 30 (after acification).

The test substance was degraded to 85%, but failed to meet the 10 day window. 60% degradation was reached 11 days after degradation passed 10%.

The reference compound was degraded to more than 60% at day 9, fufilling the validity criterion. The toxcity control showed no inhibitory effect of the test compound.