2-[10-(acetyloxy)-9a,11a-dimethyl-7-oxo-3H,3aH,3bH,4H,5H,7H,9aH,9bH,10H,11H,11aH-cyclopenta[a]phenanthren-1-yl]-2-oxoethyl acetate

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:

2010

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Report date:

2010

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 D (Ready Biodegradability: Closed Bottle Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

Prednisolone

EC Number:

200-021-7

EC Name:

Prednisolone

Cas Number:

50-24-8

Molecular formula:

C21H28O5

IUPAC Name:

11,17,21-trihydroxypregna-1,4-diene-3,20-dione

Test material form:

solid: particulate/powder

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, adapted

Details on inoculum:

- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure):The effluent of the municipal activated sludge plant of Pforzheim/Germany.
- Pretreatment: The inoculum was filtered, the first 200 mL being discarded, and was aerated by shaking one week in an Erlenmeyer flask.
- Initial cell/biomass concentration: 2.96 x 10E1 cells per mL in the test vessel.
- Water filtered: yes
- Type and size of filter used, if any: coarse filter.

Duration of test (contact time):

28 d

Initial test substance concentration

Initial conc.:

2 mg/L

Based on:

other: nominal test concentration.

Parameter followed for biodegradation estimation

Parameter followed for biodegradation estimation:

O2 consumption

Reference substance

Reference substance:

benzoic acid, sodium salt

Results and discussion

% Degradation

% Degradation 1

Key result

Parameter:

% degradation (O2 consumption)

Value:

0.3

Sampling time:

7 d

% Degradation 2

Key result

Parameter:

% degradation (O2 consumption)

Value:

4.4

Sampling time:

11 d

% Degradation 3

Key result

Parameter:

% degradation (O2 consumption)

Value:

9.7

Sampling time:

14 d

% Degradation 4

Key result

Parameter:

% degradation (O2 consumption)

Value:

13.7

Sampling time:

21 d

% Degradation 5

Parameter:

% degradation (O2 consumption)

Value:

38.2

Sampling time:

28 d

BOD5 / COD results

BOD5 / COD

Parameter:

BOD5

Value:

0 g O2/g test mat.

Results with reference substance:

With Na benzoate as reference substance a BOD5 value of 0.85 g O2/g was obtained. A BOD value of 1.18 g O2/g was obtained at day 28.

Any other information on results incl. tables

BOD mean values (mg O2/mg).

	DAY
	5	7	11	14	21	28
Prednisolone	-0.01	0.01	0.10	0.22	0.31	0.86
Na-benzoate	0.85	0.96	1.18	1.17	1.18	1.18

Individual calculations of the percentage degradation rates and mean values.

		DAY
Substance	Bottle	5	7	11	14	21	28
Prednisolone	1	0.44	0.88	7.96	-1.77	38.50	50.00
Prednisolone	2	-0.88	0.44	0.88	1.77	0.44	28.76
Prednisolone	3		-0.44		29.20	2.21	38.84
Prednisolone	Mean	-0.2	0.3	4.4	9.7	13.7	38.2
Na-benzoate	1	50.30	60.48	70.06	69.46	70.66	70.06
Na-benzoate	2	50.90	60.48	71.26	73.65	72.46	71.86
Na-benzoate	3		50.90		67.07	69.46	69.46
Na-benzoate	Mean	50.6	57.3	70.7	70.1	70.9	70.5

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Interpretation of results:

under test conditions no biodegradation observed

Conclusions:

The ready biodegradability of Prednisolone was determined with the Closed Bottle Test according to the OECD guideline 301 D. Prednisolone was tested at a nominal concentration of 2 mg/L.
The following biodegradation was determined at the end of the 28 -d period:
- Prednisolone 2 mg/L:       38.2%
- Na benzoate 2 mg/L:       70.5%
- Toxicity control:              41.6%

The test item is considered as not readily biodegradable.