Registration Dossier

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
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: well reported GLP guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1992
Report Date:
1992

Materials and methods

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

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): hydrocortisone-21-acetate (ZK 5192)
- Analytical purity: 99.4%
- Lot/batch No.: 20048246
- Expiration date of the lot/batch: Sep 1995

Study design

Oxygen conditions:
aerobic
Inoculum or test system:
sewage, domestic, non-adapted
Duration of test (contact time):
>= 28 d
Initial test substance concentrationopen allclose all
Initial conc.:
10 mg/L
Based on:
test mat.
Initial conc.:
20 mg/L
Based on:
test mat.

Results and discussion

% Degradation
Parameter:
% degradation (CO2 evolution)
Value:
> 70
Sampling time:
28 d
Details on results:
At both test concentrations, the test compound was degraded to more than 70% at the end of the incubation period. 60% degradation was reached at day 11, which was less than 5 days after the start of the degradation (i.e.10% degradation). Therefore, hydrocortison acetate is ready biodegradable. The reference compound, sodium acetate, was degraded to more than 60% on day 8, fulfilling the validity criteria.

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Interpretation of results:
readily biodegradable
Conclusions:
More than 70% at the end of the incubation period
Executive summary:

The aerobic biodegradation was studied in a CO2 evolution test according to OECD 301B. The test compound was incubated at concentrations of 10 and 20 mg/L over 28 days. At both concentrations, the test compound was degraded to more than 70% at the end of the incubation period. 60% degradation was reached at day 11, which was less than 5 days after the start of the degradation (i.e.10% degradation). Therefore, hydrocortison acetate is ready biodegradable. The reference compound, sodium acetate, was degraded to more than 60% on day 8, fulfilling the validity criteria.