2',3,4',5,7-pentahydroxyflavone

Biodegradation in water: screening tests

Administrative data

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2015

Report date:

2015

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

EU Method C.4-E (Determination of the "Ready" Biodegradability - Closed Bottle Test)

Test guideline 2

Qualifier:

according to guideline

Guideline:

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

Test guideline 3

Qualifier:

according to guideline

Guideline:

EPA OPPTS 835.3110 (Ready Biodegradability)

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

2',3,4',5,7-pentahydroxyflavone

EC Number:

207-542-9

EC Name:

2',3,4',5,7-pentahydroxyflavone

Cas Number:

480-16-0

Molecular formula:

C15H10O7

IUPAC Name:

2',3,4',5,7-pentahydroxyflavone

Constituent 2

Reference substance name:

Morin

IUPAC Name:

Morin

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.:

3.5 mg/L

Based on:

test mat.

Results and discussion

% Degradation

% Degradation 1

Parameter:

% degradation (O2 consumption)

Value:

1.8

Sampling time:

7 d

% Degradation 2

Parameter:

% degradation (O2 consumption)

Value:

13.9

Sampling time:

14 d

% Degradation 3

Parameter:

% degradation (O2 consumption)

Value:

13.2

Sampling time:

21 d

% Degradation 4

Parameter:

% degradation (O2 consumption)

Value:

15.1

Sampling time:

28 d

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Interpretation of results:

other: not ready biodegradable

Conclusions:

the test item is not ready biodegradable

Executive summary:

The test item was exposed to activated sludge from the aeration tank of a domestic waste water treatment plant. The biodegradation was followed by the oxygen uptake of the microorganisms during exposure. As a reference item Sodium benzoate (at a concentration of 3.0 mg/L) was tested simultaneously under the same conditions as the test item, and functioned as a procedure control (reference control). Additionally inoculum (containing the filtered inoculum, only) and toxicity (containing both the test item and reference item) controls were examined.

The chosen test item concentration of 3.5 mg/L investigated in the main test was based on the results of the preliminary toxicity test, and based on the calculated theoretical oxygen demand of 1.48 mg O2/ mg of the test item.

Under the test conditions ready biodegradation of this test item was not noticed, the percentage biodegradation of MORIN reached a mean of 15.1 % after 28 days based on its ThOD.

The reference item Sodium benzoate was sufficiently degraded to a mean of 72.4 % after 14 days, and to a mean of 74.5% after 28 days of incubation, based on ThOD, thus confirming the suitability of the used activated sludge inoculum.

In the toxicity control containing both, the test item and the reference item, a mean of 40.2 % biodegradation was noted within 14 days and 44.2 % biodegradation after 28 days of incubation. Thus, the test item can be assumed to not inhibit the activated sludge microorganisms (higher than 25 % degradation occurred within 14 days).