Tetrahydro-4-methyl-2H-pyran

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:

2009-08-06 to 2009-09-03

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

other: "Method for Testing the Biodegradability of Chemical Substances by Microorganisms" stipulated in the "Testing Methods for New Chemical Substances"

Version / remarks:

2006

GLP compliance:

yes

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): collected, prepared and controlled by Chemicals Evaluation and Research Institute
- Storage conditions: activated sludge was cultivated for 18.5h after the synthetic sewage has been added
- Concentration of sludge: 30 mg/L (as concentration of suspended solid)

Duration of test (contact time):

28 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: The basal culture medium was prepared based on the following method: purified water was added to each 3 mL aliquot of solutions A, B, C and D, which are described in (JIS) K 0102-2008 Section 21, in order to prepare the solution. The pH of this solution was then adjusted to 7.0.
- Test temperature: 25±1°C
- pH adjusted: Yes (culture medium)
- Continuous darkness: Yes

TEST SYSTEM
- Culturing apparatus: Vessels filled with 300 mL
- Number of culture flasks/concentration: One vessel for test item and water, 3 vessels for test item and sludge, 1 vessel with aniline and sludge (reference control), 1 vessel with medium and sludge (control blank).
- Aeration of dilution water: By using a magnetic stirrer.
- Measuring equipment: Asahi Techneion Co., Ltd.
- Test performed in closed vessels due to significant volatility of test substance: Yes

SAMPLING
- Sampling frequency: at the end of the incubation
- Sampling method: whole test solution of each vessel was used

Reference substance:

aniline

Parameter:

% degradation (O2 consumption)

Value:

1

Sampling time:

7 d

Remarks on result:

other: average

Parameter:

% degradation (O2 consumption)

Value:

2

Sampling time:

14 d

Remarks on result:

other: average

Parameter:

% degradation (O2 consumption)

Value:

2

Sampling time:

21 d

Remarks on result:

other: average

Key result

Parameter:

% degradation (O2 consumption)

Value:

2

Sampling time:

28 d

Remarks on result:

other: average

Results with reference substance:

The reference substance aniline was biodegradaded with 70% after 28 days. Furthermore, the 10-day window was fulfilled. Therefore, the test is valid.

Table 1: Percentage biodegradation of MTHP based on biochemical oxygen demand (BOD)

	7 days		14 days		21 days		28 days
Vessel No.	BOD (mg)	Deg. (%)	BOD (mg)	Deg. (%)	BOD (mg)	Deg. (%)	BOD (mg)	Deg. (%)	Mean degradation (%)
1	0	-	0.1	-	0.2	-	0.3	-	-
2	4.9	2	7.7	2	8.9	1	9.4	1	2
3	4.3	1	6.8	1	8.1	0	8.7	0
4	3.5	-	6.2	-	8.1	-	8.4	-
5	3.5	-	6.2	-	8.1	-	8.4	-	-
6	56.7	59	67.1	67	69.4	68	71.9	70	66

Vessel No. 1: Water + test item

Vessel No. 2, 3 and 4: Sludge + test item

Vessel No. 5: Sludge + water

Vessel No. 6: Sludge + aniline

Validity criteria fulfilled:

yes

Interpretation of results:

not readily biodegradable

Conclusions:

The biodegradation of the test substance MTHP was determined according to "Method for Testing the Biodegradability of Chemical Substances by Microorganisms" stipulated in the "Testing Methods for New Chemical Substances" (Japan) and in compliance with GLP. The biodegradation of MTHP was determined to be on average 2% based on the biochemical oxygen demand. MTHP is, therefore, not readily biodegradable according to OECD criteria.

Description of key information

Not readily biodegradable (biodegradation in water 2% based on BOD within 28 days)

Key value for chemical safety assessment

Biodegradation in water:

under test conditions no biodegradation observed

Additional information

The biodegradation of the test substance MTHP was determined according to "Method for Testing the Biodegradability of Chemical Substances by Microorganisms" stipulated in the "Testing Methods for New Chemical Substances" (Japan) and in compliance with GLP. The biodegradation of MTHP was determined to be on average 2% based on the biochemical oxygen demand. MTHP is, therefore, not readily biodegradable according to OECD criteria.