Dimethyl (p-methoxybenzylidene)malonate

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

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

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 F (Ready Biodegradability: Manometric Respirometry Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, non-adapted

Details on inoculum:

- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure): Activated sludge from the municipal sewage treatment plant, 31137 Hildesheim, Germany
- Preparation of inoculum for exposure: The activated sludge was washed twice with autoclaved tap water. After the second washing the settled sludge was filled up with mineral salts medium and was maintained in an aerobic condition by aeration for 4 hours. Thereafter the sludge was homogenized with a blender. The supernatant was decanted and maintained in an aerobic condition by aeration with CO2-free air for 6 days.
10 mL/L were used to initiate inoculation.
- Initial cell/biomass concentration: 1.9x10)9 CFU/L
- Water filtered: no

Duration of test (contact time):

28 d

Initial conc.:

40 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

O2 consumption

Reference substance:

benzoic acid, sodium salt

Remarks:

45 mg/L

Preliminary study:

No preliminary study

Key result

Parameter:

% degradation (O2 consumption)

Value:

17

Sampling time:

28 d

Details on results:

In the toxicity control the biodegradation achieved 49 % after 14 days. After 28 days the biodegradation came to 57 %. The validity criterion that the test item should not inhibit the biodegradation of the reference item was fulfilled.
In case of the functional control, the adaptation phase changed to degradation phase after 1 day (degradation > 10 %). The pass level > 60 % was reached after 2 days. The biodegradation rate came to a maximum of 90 % on day 24 .
The biodegradation of the test item is shown in comparison to the readily degradable functional control and the toxicity control. Both test item replicates reached the 10 % level (beginning of biodegradation) after 7 days. After 28 days the mean biodegradation was 17 %.

The test item is classified as not readily biodegradable in the 10-d-window and after 28 days.

Results with reference substance:

The pass level of a biodegradation > 60 % was reached after 2 days. The validity criterion that the degradation should be > 60 % after 14 d was fulfilled.

Validity criteria fulfilled:

yes

Remarks:

The percentage degradation of the functional control reached the pass level of 60 % after 2 days (validity criterion: 60 % after 14 days); The oxygen depletion in the inoculum control was 8.5 mg oxygen/L on day 28 (validity criterion: < 60 mg oxygen/

Interpretation of results:

not readily biodegradable

Conclusions:

After 28 days, the mean biodegradation was 17 %. The test item is classified as not readily biodegradable in the 10 d-window and after 28 days.

Executive summary:

The ready biodegradability of the test item Hostavin PR-25 was determined with a non adapted activated sludge in the Manometric Respirometry Test for a period of 28 days according to OECD guideline 301 F. After 28 days the mean biodegradation rate was 17 %.

Description of key information

Biodegradation of the submission substance: 17 % after 28 days (OECD 301F, 2010)

Key value for chemical safety assessment

Biodegradation in water:

under test conditions no biodegradation observed

Additional information

In a reliable key study, ready biodegradability of the submission substance was determined with a non-adapted activated sludge in the Manometric Respirometry Test for a period of 28 days (RL1). The test was performed according to OECD guideline 301 F and in compliance with GLP. After 28 days, the mean biodegradation was 17 %. The test item was classified as not readily biodegradable in the 10 d-window and after 28 days. The test was considered reliable and adequate for the environmental fate assessment of the submission substance.