Hydrocarbons, C10, aromatics, <1% naphthalene

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:

11-May-2001 to 8-Jun-2001

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: This robust summary has a reliability rating of 2 because the study followed a standard test guideline, there were no deviations from the protocol, however it was not conducted under GLP.

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

GLP compliance:

no

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

Inoculum used as the source of the microorganisms was an aliquot of fresh activated sludge from a domestic wastewater treatment facility in New Jersey, USA.

Duration of test (contact time):

28 d

Initial conc.:

ca. 50 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

Test material was tested in triplicate, controls and blanks were tested in duplicate. The amount of oxygen consumed by microorganisms from the oxidation of the test material was continuously monitored by an automated respirometer during the 28-day test period. Test material concentration was approximately 50mg/L. Sodium benzoate (positive control) concentration was 50mg/L. All test vessels were stirred constantly for 28 days
using magnetic stir bars and plates.

Reference substance:

benzoic acid, sodium salt

Parameter:

% degradation (O2 consumption)

Value:

1.79

St. dev.:

2.29

Sampling time:

5 d

Parameter:

% degradation (O2 consumption)

Value:

5.73

St. dev.:

0.55

Sampling time:

6 d

Parameter:

% degradation (O2 consumption)

Value:

29

St. dev.:

1

Sampling time:

7 d

Parameter:

% degradation (O2 consumption)

Value:

42.63

St. dev.:

2.02

Sampling time:

13 d

Key result

Parameter:

% degradation (O2 consumption)

Value:

49.56

St. dev.:

0.37

Sampling time:

28 d

Details on results:

Test material was inherently biodegradable. Half-life was approximately 4 weeks. By day 28, approximately 49.6% degradation of the test material was observed. 10% biodegradation was achieved on approximately day 7, 50% biodegradation was not achieved. By day 14, >60% biodegradation of positive control was observed, which meets the guideline requirement. No excursions from the protocol were noted.

Biodegradation was based on oxygen consumption and the theoretical oxygen demand of the test material as calculated using results of an elemental analysis of the test material.

Results with reference substance:

Sodium benzoate, the positive control, achieved 88.7% with a standard deviation of 2.71% degradation after 28 days, and therefore this test may be considered valid.

	% Degradation*	Mean % Degradation
Sample	(day 28)	(day 28)
Test Material	49.8, 49.3	49.6
Na Benzoate	89.6, 85.7, 90.9	88.7

* replicate data

Validity criteria fulfilled:

yes

Interpretation of results:

inherently biodegradable

Conclusions:

Hydrocarbons, C10, aromatics, <1% naphthalene, biodegraded 49.6% after 28 days under the conditions of the study and is inherently biodegradable.

Executive summary:

Hydrocarbons, C10, aromatics, <1% naphthalene, biodegraded 49.6% after 28 days under the conditions of the study and is inherently biodegradable.

Description of key information

Hydrocarbons, C10, aromatics, <1% naphthalene, biodegraded 49.6% after 28 days in an aerobic OECD 301F test, and under the conditions of the study and is inherently biodegradable.