6-sec-butylquinoline

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:

18 December 1997 - 19 January 1998

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)

Version / remarks:

(1992)

Deviations:

yes

Remarks:

the pH was above the guideline limit of 8.5 (max pH variation <1.5) in one of the duplicate flasks of both the reference substance and the inoculum blank but this is not expected to affect the study result.

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

- Name of test material (as cited in study report): Butyl Quinoline Sec.
- Chemical nature: 6(8)-(1-methylpropyl)quinoline
- Empirical formula: C13H15N
- Molecular weight: 185.3 g/mol
- CAS number: 65442-31-1 and 67634-06-4
- Lot No.: 275082
- Purity: 99.5% (GC, sum of the two isomers)
- Physical state: Liquid (pale yellow color)

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic (adaptation not specified)

Details on inoculum:

- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure): Fresh activated sludge collected from a biological waste water treatment plant treating predominantly domestic sewage (City of Geneva, Aïre).
- Preparation of inoculum for exposure: The sludge was collected in the morning, washed three times in the mineral medium (by centrifuging at 1000 g for 10 minutes, discarding the supernatant and resuspending in mineral medium).
- Storage length: <24h (kept aerobic until use on the same day of collection)
- Concentration of sludge: Dry weight of suspended solids was 3.225 g/L
- Water filtered: no

Duration of test (contact time):

31 d

Initial conc.:

100 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

TEST CONDITIONS
- Composition of medium: Prepared according to guideline
- Test temperature: 22 °C
- Blank control: The initial pH was 7.28 for both flasks. The final pH was 7.75 and 11.44
- Test flasks: The initial pH was 7.28 for both flasks. The final pH was 7.48 and 7.49
- pH adjusted: no
- Stirring: yes
- Suspended solids concentration: 30 mg/L (dry weight)

TEST SYSTEM
- Culturing apparatus: A water bath with attached oxygen meters (SAPROMAT D12)
- Number of culture flasks/concentration: 2
- Measuring equipment: The respirometer used during this study is a SAPROMAT D 12, made by J. M. VOITH GmbH, D-7920 Heidenheim, Germany.
- Test performed in open system: No
- Details of trap for CO2: soda lime
- Every day the oxygen consumption of each flask was recorded and correct temperature and stirring were checked.
- Other: The water used contained less than 10 mg/L of dissolved organic carbon.

SAMPLING
- Sampling frequency: At the end of the test
- Sample storage before analysis: No

CONTROL AND BLANK SYSTEM
- Inoculum blank: yes
- Abiotic sterile control: no
- Toxicity control: yes

Reference substance:

other: Sodium benzoate

Key result

Parameter:

% degradation (O2 consumption)

Value:

0

St. dev.:

0

Sampling time:

31 d

Details on results:

Validity criteria:
- The repeatability validity criterion (not more than 20% difference between replicates) is fulfilled;
- In the toxicity control (containing both 100 mg/L of test substance and the reference substance) the degradation rate of the reference substance was similar to the rate in the flasks containing only the reference substance. Therefore, it was concluded the substance was not toxic to activated sludge microorganisms.
- The oxygen uptake of the inoculum blank varied between 21-25 mg 02/L at test day 28. Thus, the oxygen uptake was lower than 60 mg/L as required by the guideline.
- In one of the duplicate flasks containing the test substance it was reported a high pH value (11.44) due to a small leak of soda lime from the attachment of the stopper to the test flask. A similar increase in pH (11.15) was also reported for one of the duplicates containing the reference substance. Despite the increase in pH no significant differences were observed between the degradation rate of the duplicates. Therefore, this deviation does not seem to significantly affect the results of the biodegradation test.

Results with reference substance:

- The pH in one of the flasks containing the reference substance (sodium benzoate) was above the guideline limit of 8.5. Nonetheless, no significant differences were observed between the duplicates and the percentage sodium benzoate degraded at test day 7 was 89% and at day 14 it reached 100% degradation. Thus, the activity of the inoculum is verified.

Validity criteria fulfilled:

yes

Remarks:

Despite the increase in pH no significant differences were observed between the degradation rate of the duplicates. This allows to conclude that the deviating pH was due to an experimental error and did not affect the outcome of the present study.

Interpretation of results:

under test conditions no biodegradation observed

Conclusions:

Under the test conditions of the Manometric Respirometry Test (OECD 301F), Sec Butyl Quinoline undergoes no biodegradation after 28 days (0 % after 31 days).

Executive summary:

The ready biodegradability of Sec Butyl Quinoline was investigated in a study conducted in accordance with OECD Guideline 301F (Manometric Respirometry Test) and GLP principles. The study was performed at 1 test concentration of the test substance (100 mg/L) plus a inoculum blank and a toxicity control. A reference substance (sodium benzoate) was also tested. The test substance undergoes no biodegradation after 28 days (0 % after 31 days) and it was not toxic to the inoculum. The validity criteria of the test guideline were fulfilled despite the pH being above the guideline limit of 8.5 (max pH variation <1.5) which was not considered to affect the outcome of the present study. In conclusion, the substance is not readily biodegradable under the conditions of this test.

Key value for chemical safety assessment

Biodegradation in water:

under test conditions no biodegradation observed

Type of water:

other: deionised water containing less than 10 mg/l dissolved organic carbon