A mixture of: trans-4-acetoxy-4-methyl-2-propyl-tetrahydro-2H-pyran; cis-4-acetoxy-4-methyl-2-propyl-tetrahydro-2H-pyran

Biodegradation in water: screening tests

Administrative data

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Study conducting according to OECD method by a GLP accredited laboratory.

Data source

Reference

Reference Type:

other: Body responsible for the test

Title:

Unnamed

Year:

1991

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 D (Ready Biodegradability: Closed Bottle Test)

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method C.6 (Degradation: Chemical Oxygen Demand)

Version / remarks:

Directive 84/449/EC, Annex V.

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

A mixture of: trans-4-acetoxy-4-methyl-2-propyl-tetrahydro-2H-pyran; cis-4-acetoxy-4-methyl-2-propyl-tetrahydro-2H-pyran

EC Number:

412-450-9

EC Name:

A mixture of: trans-4-acetoxy-4-methyl-2-propyl-tetrahydro-2H-pyran; cis-4-acetoxy-4-methyl-2-propyl-tetrahydro-2H-pyran

Cas Number:

131766-73-9

Molecular formula:

C11H20O3

IUPAC Name:

reaction mass of: trans-4-acetoxy-4-methyl-2-propyl-tetrahydro-2H-pyran cis-4-acetoxy-4-methyl-2-propyl-tetrahydro-2H-pyran

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic (adaptation not specified)

Details on inoculum:

Inoculum was obtained from activated sewage sludge by allowing the sample (predominately domestic sewage) to settle and then filtering the supernatant through Whatman GFA filter paper. The first 250 ml was discarded.

Duration of test (contact time):

28 d

Initial test substance concentration

Initial conc.:

2 mg/L

Parameter followed for biodegradation estimation

Parameter followed for biodegradation estimation:

DOC removal

Details on study design:

Test substance and standard were directly dispersed in nutrient medium. Four series were prepared: (a) non-inoculated nutrient medium; (b) inoculated nutrient medium; (c) 2 mg test substance/L; and (d) 3 mg sodium benzoate (standard)/L. Inoculation of the nutrient broth (1 drop of inoculum/L) was done immediately prior to the preparation of the series (b-d) and after preparation of series (a). A sufficient number of 280-ml biochemical oxygen demand bottles with glass stoppers were used to allow a single oxygen determination per bottle on days 0, 5, 15, and 28 for test and control series (duplicate bottles at each sampling time). The bottles were filled, stoppered to exclude all air bubbles, and then incubated in a water bath at 20±1°C.
Percent biodegradation was calculated by comparing the oxygen depletion value with the corresponding Theoretical Oxygen Demand (4.64 mg O2/L for test substance at 2 mg/L and 5.01 mg O2/L for standard at 3 mg/L).

Reference substance

Reference substance:

benzoic acid, sodium salt

Remarks:

3 mg/l

Results and discussion

% Degradation

% Degradation 1

Parameter:

% degradation (DOC removal)

Value:

3

Sampling time:

5 d

% Degradation 2

Parameter:

% degradation (DOC removal)

Value:

23

Sampling time:

15 d

% Degradation 3

Parameter:

% degradation (DOC removal)

Value:

38

Sampling time:

28 d

Details on results:

After 5, 15, and 28 days, mean O2 depletion (as mg O2/L) was 0.150, 1.050, and 1.750, respectively, and percentage biodegradation was 3, 23, and 38, respectively.

BOD5 / COD results

BOD5 / COD

BOD5 / COD 1

Parameter:

BOD5

Value:

0.08 g O2/g test mat.

BOD5 / COD 2

Parameter:

COD

Value:

2.32 g O2/g test mat.

BOD5 / COD 3

Parameter:

BOD5*100/COD

Value:

3.2

Any other information on results incl. tables

A separate BOD determination was not carried out. From the biodegradability test, the BOD at 5 days was 0.075 g/g. COD was not determined. The theoretical oxygen demand (ThOD) was calculated as 2.32 g/g.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Remarks:

Oxygen depletions in controls were within prescribed limits.

Interpretation of results:

other: not readily biodegradable

Conclusions:

Although substantial biodegradation was recorded after 28 days of incubation, the test substance was not readily biodegradable under the conditions of the closed bottle test.

Executive summary:

The ready biodegradability of the test substance was assessed by employing the closed bottle test according to OECD guideline 301D. The test substance in water was inoculated with activated sewage sludge. Sodium benzoate served as the control. The dissolved oxygen concentration was measured on days 0, 5, 15, and 28 for test and control series. The test substance attained only 38% biodegradation after 28 days and was not considered readily biodegradable.