Benzene, mono-C10-13-alkyl derivs., distn. residues

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:

Dec. 8, 1992-Jan. 13, 1993

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Comparable to guideline study.

Qualifier:

according to guideline

Guideline:

other: BODIS - Test (BOD-test for insoluble substances)

GLP compliance:

yes (incl. QA statement)

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge (adaptation not specified)

Details on inoculum:

- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure): activated sludge from Lippeverbands, Germany domestic purification plant
- Concentration of sludge: 1.7 g/L

Duration of test (contact time):

28 d

Initial conc.:

5.4 other: mg/flask

Based on:

test mat.

Initial conc.:

5.8 other: mg/flask

Based on:

test mat.

Initial conc.:

6 other: mg/flask

Based on:

test mat.

Parameter followed for biodegradation estimation:

O2 consumption

Reference substance:

diethylene glycol

Parameter:

% degradation (O2 consumption)

Value:

28

Sampling time:

28 d

Results with reference substance:

The test substance was 87% degraded during the test, and achieved 60% degradation within 10 days of being 10% degraded. The test is therefore valid.

Validity criteria fulfilled:

yes

Interpretation of results:

other: poorly biodegradable

Conclusions:

This study demonstrated that the insoluble test material is poorly biodegradable, with 28% degradation in 28 days.

Executive summary:

This study examined the potential of the test substance to biodegrade. Samples of activated sludge were exposed to 5.4, 5.8, and 6.0 mg/flask of test substance. Diethylene glycol was used as the reference substance. Oxygen measurements were taken at 7, 14, 21, and 28 days. The test substance was only 28% degraded at the end of 28 days. Results with the reference substance were valid. The test substance is not readily biodegradable.

Description of key information

The key study was conducted to examine the potential of the test substance to biodegrade using the BODIS test for insoluble substances. Samples of activated sludge were exposed to 5.4, 5.8, and 6.0 mg/flask of the test substance. Diethylene glycol was used as the reference substance. Oxygen measurements were taken at 7, 14, 21, and 28 days. The test substance degraded 28% by the end of 28 days. Results with the reference substance were valid. Therefore, the study demonstrates that HAB will biodegrade slowly in the environment but does not meet the criteria for ready biodegradability.

Key value for chemical safety assessment

Type of water:

freshwater