4,4'-dihydroxybenzophenone

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:

29 days

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 B (Ready Biodegradability: CO2 Evolution Test)

GLP compliance:

yes

Specific details on test material used for the study:

Batch number: 20111104
Purity / Composition: >99.5% CAS # 611-99-4
Chemex reference: ECO170601

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge (adaptation not specified)

Details on inoculum:

Source: Cambridge Sewage Treatment Works, Cowley Road
Date of collection: 08 August 2017
Sludge pre-treatment: Sieved to 850μm to remove coarse particulates, settled and centrifuged at ~ 4000rpm for ~ 5-10 minutes. The supernatant discarded, sludge resuspended in mineral media and centrifuged at ~4000rpm for ~ 5-10 minutes.This stage repeated once more then the supernatant discarded again and
homogenised thoroughly by mechanical stirring (spoon).Dry sludge solids determined on the pellet produced.
Dry sludge solids: 6.10%
Volume of mineral medium: 1.5l per bioreactor
Dry sludge solids in test: 0.0300g/l

Duration of test (contact time):

28 d

Initial conc.:

30.035 other: mg

Based on:

TOC

Parameter followed for biodegradation estimation:

CO2 evolution

Reference substance:

acetic acid, sodium salt

Key result

Parameter:

% degradation (CO2 evolution)

Value:

ca. 45

Sampling time:

7 d

Key result

Parameter:

% degradation (CO2 evolution)

Value:

ca. 76

St. dev.:

3

Sampling time:

14 d

Key result

Parameter:

% degradation (CO2 evolution)

Value:

ca. 80

St. dev.:

0.5

Sampling time:

28 d

Details on results:

4,4 DIHYDROXYBENZOPHENONE gave a positive result (>=60% degradation relative to the ThCO2 value) with a maximum of 104% recorded on day 29. It may therefore be concluded that there is a potential for biodegradation under environmental conditions.The inoculum blank should not normally produce more than 70mg/l CO2 (19.1mg/l C) for the test to be valid. A value of 50.8mg/l CO2 (13.9mg/l C) was recorded. The guideline requires that the reference material degrades by at least 60% of its ThCO2 value, a maximum value of 97% degradation of the sodium acetate was achieved on day 29.
The test protocol requires that a 10-day window is applied to the degradation results (60% degradation to be reached within 10 days of 10% of the theoretical carbon dioxide produced). 4,4 DIHYDROXYBENZOPHENONE did achieve 61% degradation on day 9, therefore the 10-day window was passed.

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable

Conclusions:

4,4 DIHYDROXYBENZOPHENONE gave a positive result (60% degradation relative to the ThCO2 value) with a maximum of 104% recorded on day 29. It may therefore be concluded that there is a potential for biodegradation under environmental conditions.
It achieved 61% degradation on day 9, therefore the 10-day window was passed.
The final conclusion of this study is therefore that 4,4 DIHYDROXYBENZOPHENONE is readily biodegradable under the conditions of this test.

Description of key information

4,4 DIHYDROXYBENZOPHENONE gave a positive result (>=60% degradation relative to the ThCO2 value) with a maximum of 104% recorded on day 29. It may therefore be concluded that there is a potential for biodegradation under environmental conditions.

It achieved 61% degradation on day 9, therefore the 10-day window was passed.

The final conclusion of this study is therefore that 4,4 DIHYDROXYBENZOPHENONE is readily biodegradable under the conditions of this test.

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable