α,2,2,6-tetramethylcyclohexene-1-butyraldehyde

Biodegradation in water: screening tests

Administrative data

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

20-12-2005

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: According to OECD Guideline No. 301 F and in compliance GLP

Cross-reference

Cross-reference 1

Reason / purpose for cross-reference:

reference to same study

Cross-reference 2

Reason / purpose for cross-reference:

reference to other study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2006

Report date:

2006

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

Principles of method if other than guideline:

Not relevant

GLP compliance:

yes (incl. QA statement)

Remarks:

GLP Certificate of Swiss Monitoring Authorities, November 2005

Test material

Test material information

Constituent 1

Reference substance name:

α,2,2,6-tetramethylcyclohexene-1-butyraldehyde

EC Number:

265-747-9

EC Name:

α,2,2,6-tetramethylcyclohexene-1-butyraldehyde

Cas Number:

65405-84-7

Molecular formula:

C14H24O

IUPAC Name:

2-methyl-4-(2,6,6-trimethylcyclohex-2-en-1-yl)butanal

Details on test material:

- Name of test material (as cited in study report): Dihydro-C14-aldehyde
- Physical state: liquid
- Storage condition of test material: At room temperature (at about 20 °C), in a tightly closed container

Specific details on test material used for the study:

Details on properties of test surrogate or analogue material (migrated information):
Not relevant

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

Fresh activated sludge
Treatment: washed twice and brought to 4 g SS/litre.
Pre-acclimation: Aeration of sludge at room temperature was done during holding;
Thorough mixing and dilution was done with test water and then diluted to a concentration of 1g dry material/litre before the test.
Final concentration 30 mg dry material/litre
Source: ARA Ergolz II, Fullinsdorf, Switzerland (wastewater treatment plant)

Duration of test (contact time):

28 d

Initial test substance concentration

Initial conc.:

>= 100 - <= 101 mg/L

Parameter followed for biodegradation estimation

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

Temperature of incubation: 22° C
Dosing procedure: Weighed amount of test item transferred to 500 ml erlenmeyers with mineral medium. Equal aliquots of the reference item, Sodium Benzoate, were added to appropriate flasks with test water. Activated sludge was added to each test flask, except Abiotic Control flask to make the
final volume to 250 ml/test flask.
Sampling frequency: Daily reading of oxygen consumption was taken manually
Appropriate controls and blank system
used Inoculum control: Without test and reference items
Procedure control: With the reference item, without test item
Abiotic control: With test item, without reference item and inoculum, and poisoned with mercury dichloride @ 10 mg/litre
Toxicity control: Containing both the test and reference items
Method of calculating measured concentrations: % Biodegradation = BOD (mg O2/mg chemical)/ThOD (mg O2/mg chemical) x 100
where, BOD = Biochemical oxygen demand of test or reference item, ThOD = Theoretical oxygen demand of test or reference item
Test medium: according to OECD 301F.
pH: day 0: 7.4-7.5; day 28: 7.3 - 7.8

Reference substance

Reference substance:

benzoic acid, sodium salt

Remarks:

99.8% purity, test concentration 100 mg/l

Results and discussion

Preliminary study:

no preliminary study included

Test performance:

Test performance was in line with the guideline

% Degradation

Key result

Parameter:

% degradation (O2 consumption)

Value:

ca. 54

Sampling time:

28 d

Details on results:

1. Biodegradation of Test Item
- Time dependent increase in BOD from Exposure Day 7 onwards
- ThOD = 3.0 mg O2/mg Test Item
- Mean Biodegradation - 54% within 28 days
- Biodegradation of at least 60% of ThOD in a 10 day window within the 28 day period
was not reached(pass level for biodegradability)
2. Biodegradation of Abiotic control
- No biodegradation under test conditions within 28 days
3. Biodegradation of Reference Item
- ThOD = 1.67 mg O2/mg Test Item
- Mean Biodegradation - 83% by day 14 and 84% by day 28
4. Biodegradation of Toxicity control
- Mean Biodegradation - 47% by day 14
- Biodegradation > 25% within 14 days (No inhibitory effect on microorganisms at test concentration)

Kinetics for each time period:
Test Item: Increase in % biodegradation from day 2 onwards (Day 10 - 81%, Day 14 - 84%, Day 28 - 86%)
Procedure control: Sudden increase in % biodegradation from day 2 onwards (Day 10 - 84%, Day 14 - 87%, Day 28 - 90%)
Toxicity Control: Increase in % biodegradation from day 2 onwards (Day 10 - 62%, Day 14 - 69%, Day 28 - 82%)

BOD5 / COD results

Results with reference substance:

- ThOD = 1.67 mg O2/mg Test Item
- Mean Biodegradation was 83% by day 14 and 84% by day 28

Any other information on results incl. tables

According to the test with the reference item, the inoculum performed well. According to the toxicity control, the test substance was not toxic at the level tested. According to the abiotic control, there was no CO2 production under abiotic conditions. Mean biodegradation was 54% in 28 days.The pass level for ready biodegradation was not reached

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Remarks:

yes - Oxygen uptake in blank < 60 mg/l in 28 d; - pH between 6-8.5; - Difference between extremes < 20%; % of degradation of reference substance after 14d > pass level ; - In Toxicity control, degradation is > 35% (based on DOC) or > 25% (based on ThOD)

Interpretation of results:

other: biodegradable

Conclusions:

The test substance was tested according to OEC Guideline 301F. The results show that the substance is considered to be " biodegradable" withing 28 days, not meeting the 10-d window.

Executive summary:

The test item Dihydro-Cl4-Aldehyde was investigated for its ready biodegradability in a

manometric respirometry test over 28 days according to EU Commission Directive 92/69

EEC, C.4-D (1992) and OECD Guideline for Testing of Chemicals No. 301 F (1992).

The percent biodegradation of the test item was calculated based on the theoretical oxygen

demand (ThOD) of 3.0 mg 02/mg test item.

The biochemical oxygen demand (BOD) of Dihydro-C14-Aldehyde in the test media

significantly increased from Day 7 until test termination after 28 days. At the end of the

28-day exposure period, the mean biodegradation of Dihydro-C14-Aldehyde amounted to

54 %.

Consequently, Dihydro-C14-Aldehyde was biodegradable under the conditions of the test

within 28 days. However, the pass level for ready biodegradability, i.e. biodegradation of at

least 60% of the ThOD in a 10-day window within the 28-day period of the test, was not

reached.

Oxygen consumption in the abiotic control was measured from Day 3 until test termination

after 28 days. Thus, an abiotic degradation process occurs in addition to biodegradation,

however to a much lesser extent.

In the toxicity control, containing both Dihydro-C14-Aldehyde and the reference item sodium

benzoate, no inhibitory effect on the biodegradation of the reference item was determined.

Thus, Dihydro-C14-Aldehyde had no inhibitory effect on the activity of activated sludge

microorganisms at the tested concentration of 100 mg/L.

In the procedure controls, the reference item sodium benzoate was degraded by an average

of 83% on exposure Day 14, and reached an average biodegradation of 84% by the end of

the test (Day 28), thus confirming the suitability of the activated sludge.