2,3,4-trihydroxybenzophenone

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Justification for type of information:

Please refer to the Analogue Justification provided in Section 13.

Reason / purpose for cross-reference:

read-across source

Key result

Parameter:

% degradation (CO2 evolution)

Value:

>= 10 - <= 28

Sampling time:

28 d

Description of key information

The test item is regarded to be not readily biodegradable in the 10-d-window and after 28 days based on data generated with the read-across source substance.

Key value for chemical safety assessment

Biodegradation in water:

not biodegradable

Type of water:

freshwater

Additional information

No study data with the test item is available for biodegradation. Therefore, a read-across to the read-across substance with a very similar chemical structure and comparable physico-chemical parameters is used to evaluate the potential for biodegradation of the test item.

The ready biodegradability was determined with a non adapted activated sludge for the test item over a test period of 28 days in the Modified Sturm Test according to OECD TG 301B. The test item was tested on a concentration of 20 mg/L in duplicates, corresponding to a carbon content (TOC) pf 12.7 mgC/L in the test vessels. The biodegradation of the test item was followed by titrimetric analyses of the quantity of CO2, which was produced by the respiration of bacteria. The degradation was finished on day 28 by acidification, the last titration was made on day 29, after the soluble CO2 was tuned out over a period of 24 h. The CO2 production was calculated as the percentage pf total CO2 that the test item could have theoretically produced bas on carbon content. Biodegradation is therefore expressed as percentage ThCO2 and was calculated for each titration of CO2. In order to check the activity of the test system sodium acetate was used as a functional control. The percentage degradation of the functional control reached the pass level of 60 % after 10 days. The validity criterion of the guideline was fulfilled. In the toxicity control containing bot the test and reference item a biodegradation rate of 39 % occurred within 14 days and cam to a maximum of 46 % after 28 days. The biodegradation of the reference item was not inhibited by the test item in the toxicity control. The test item reached the 10 % level (beginning of degradation) after 8 days. The pass level of a biodegradation > 60 % was not reached nightery in the 10-d-window not after 28 days- After 14 days the biodegradation rate of the first replicate came to 16 % and to a maximum of 28 % after 28 days. The second replicate reached a biodegradation rate of 11 % after 14 days and the plateau. The test item is regarded to be not readily biodegradable in the 10-d-window and after 28 days. The validity criteria according to the guideline are fulfilled.