4-Ethoxy-2,3-difluoro-4'-methyl-1,1'-biphenyl

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:

2015 Dec 21 to 2016 Feb 03

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:

not specified

GLP compliance:

yes (incl. QA statement)

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, adapted

Details on inoculum:

Sludge collection: a fresh sample of activated sludge was collected on Jan 6th, 2016 from the aeration tank of the Long Hua Wastewater Treatment Plant in Shanghai which treats predominantly domestic sewage. The activated sludge was kept by aeration until used (non-aeration during transport from the wastewater treatment plant to the laboratory was kept to a minimum).
Sludge treatment: When back to the laboratory, the sludge was washed with mineral medium.
After centrifugation, the supernatant was decanted. This procedure was repeated three times (4000 rpm, 4 °C, centrifuge 20 minutes). Then, 1.036 g of the concentrated sludge was weighed, dried at 105 °C for 1 h and then measured by moisture meter for 1 h to determine the dry weight. The dry weight of concentrated sludge was 6.85 %.

Sludge suspension: According to the dry weight, 43.8 g of concentrated sludge was calculated and suspended in 1 L mineral medium to yeild a concentration of 3 g suspended solids/L. The final concentration of the activated sludge in the test medium was 30 mg/L.

Duration of test (contact time):

28 d

Initial conc.:

21.77 mg/L

Based on:

test mat.

Remarks:

final concentration was clearly above water solubility

Parameter followed for biodegradation estimation:

O2 consumption

Reference substance:

benzoic acid, sodium salt

Key result

Parameter:

% degradation (O2 consumption)

Value:

3

Sampling time:

28 d

Details on results:

Under the test conditions no biodegradation of test item could be observed.
The percentage degradation did not exceed 60 % within the 10-day window and after 28 days of incubation.
The test item is considered not readily biodegradable.
The reference Item sodium sodium benzoate was sufficiently degraded to 74 % after 14 days. The percentage degradation (> 60 % after 14 days) of the reference item confirms the suitability of the used activated sludge inoculum.

The oxygen demand in the abiotic control was zero; no correction of the test item degradation rates had to be done.

Results with reference substance:

The reference Item sodium sodium benzoate was sufficiently degraded to 74 % after 14 days. The percentage degradation of the reference item confirms the suitability of the used activated sludge inoculum.

Validity criteria fulfilled:

yes

Interpretation of results:

under test conditions no biodegradation observed

Conclusions:

Under the test conditions no biodegradation of test item could be observed. The percentage degradation did not exceed 60 % within the 10-day window and after 28 days of incubation. The test item is considered not readily biodegradable.

Executive summary:

In this OECD 301F Assay the results show no biodegradation of test item.

The percentage degradation did not exceed 60 % within the 10-day window and after 28 days of incubation. The test item is considered not readily biodegradable.

The reference item sodium sodium benzoate was sufficiently degraded to 74 % after 14 days and 79 % after 28 days of incubation. The percentage degradation of the reference item confirms the suitability of the used activated sludge inoculum.

According to the test guidelines the test item can be assumed to be not inhibitory on the activated sludge micro organisms because degradation was > 25 % within 14 days.

The oxygen demand in the abiotic control was zero; no correction of the test item degradation rates had to be done.

Description of key information

Under the test conditions no biodegradation of test item could be observed. The percentage degradation did not exceed 60 % within the 10-day window and after 28 days of incubation. The test item is considered not readily biodegradable.

Key value for chemical safety assessment

Biodegradation in water:

not biodegradable

Type of water:

freshwater

Additional information

In this OECD 301F Assay the results show no biodegradation of test item.

The percentage degradation did not exceed 60 % within the 10-day window and after 28 days of incubation. The test item is considered not readily biodegradable.

The reference item sodium sodium benzoate was sufficiently degraded to 74 % after 14 days and 79 % after 28 days of incubation. The percentage degradation of the reference item confirms the suitability of the used activated sludge inoculum.

According to the test guidelines the test item can be assumed to be not inhibitory on the activated sludge micro organisms because degradation was > 25 % within 14 days.

The oxygen demand in the abiotic control was zero; no correction of the test item degradation rates had to be done.