p-menth-1-en-8-ol

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Principles of method if other than guideline:

- Principle of test: Test material was evaluated for degradation by cultures derived from coniferous forest soil, diluted and used directly without any prior enrichment.
- Short description of test conditions: see below
- Parameters analysed / observed: see below

GLP compliance:

not specified

Oxygen conditions:

aerobic

Inoculum or test system:

natural soil

Details on inoculum:

- Source of inoculum: The primary inocula for this study were prepared from extracts of soil samples collected from a coniferous forest (soil A) and mixed hardwood forest (soil B) watersheds at the Coweeta Hydrologic Laboratory, Otto, N.C.
- Preparation of inoculum for exposure: Soil extracts were prepared by passing soil/water mixtures through a 500-µm sieve, followed by 2 h settling. The resulting supernatants were used as the inoculum.

Initial conc.:

>= 5 - <= 40 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

test mat. analysis

Parameter followed for biodegradation estimation:

CO2 evolution

Parameter followed for biodegradation estimation:

other: biomass concentration

Details on study design:

TEST CONDITIONS
- Composition of medium: Minimal media were prepared in distilled, deionized water and consisted of the following salts (in mg/l): KH2PO4 700, K2HPO4 2000, NH4Cl 150, CaCl2 * 2H2O 15, NaCl 10, FeCl2 * 4H2O 10, MnCl2 * 4H2O 10.
- Test temperature: 23ºC
- pH: 7.1
- Aeration of dilution water: continuous mixing using magnetic stirrers (at approx. 300 rpm)
- Continuous darkness: yes
- Other: The reactor was flushed with pure oxygen and then 1.4 l oxygen saturated minimal medium was added. Undiluted monoterpene was added. After 24 h equilibration, soil A/soil B extract was added to the reactor at 1% (v/v).

TEST SYSTEM
- Culturing apparatus: Glass flask (2 l) equipped with two glass/Teflon valves and a septum-sealed port.
- Number of culture flasks/concentration: 1

SAMPLING
- Sampling frequency: At regular intervals, duplicate gas and liquid samples were removed and analyzed for test substance and CO2.

CONTROL AND BLANK SYSTEM
- Inoculum blank: 1 control contained sodium azide at a concentration of 2.5 g/l.

Key result

Parameter:

other: Maximum degradation rate (mg/L/h)

Value:

> 0.1

Sampling time:

94 h

Remarks on result:

other: Unacclimated soil-A extract

Details on results:

The detection of CO2, the increase in biomass concentration and lack of any substantial change in the concentration of terpene in the azide-amended control reactor demonstrated that biodegradation of alpha terpineol took place and that its disappearance was not the result for hydrolysis or any other physicochemical process (e.g., volatilization of the hydrocarbon monoterpenes).

Experiment/ compound	Reactor type	Inoculum	Lag period (h)	Maximum degradation rate (mg l^-1h^-1)	Normalized degradation rate (h^-1)
Experiment 1
α-terpineol	CSR2	Unacclimated soil A extract	94	>0.10a	NM
Experiment 3B
α-terpineol	CSR3	terpineol-enriched soil B extract	0	13.6	0.255

The normalized degradation rate is the maximum degradation rate normalized to biomass concentration expressed as volatile suspended solids

CSR 2, CSR 3: continuously-stirred reactor 2 and 3

NM: not measured because of lack of accurate biomass data

a: Limited data available

Validity criteria fulfilled:

not specified

Interpretation of results:

readily biodegradable

Conclusions:

Under the test conditions, alpha terpineol was readily degraded by cultures derived from forest soils.

Executive summary:

In a ready biodegradation study, alpha terpineol was tested at concentrations of 5 -40 mg/L. Forest-soil extract cultures were used as inocula. The degradation of the test material was assessed by the determination of the biomass, concentration of the test material and headspace CO2. The test treatments and control (sodium azide, 2.5 g/L) were measured in duplicates. The lack of any substantial change in alpha terpineol concentration in the azide-amended control reactor demonstrated that disappearance of the test item in the test reactor was not the result of hydrolysis or any other physicochemical process. Under the test conditions, alpha terpineol was readily degraded by cultures derived from forest soils.

Reference 2

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

1978

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 301 C (Ready Biodegradability: Modified MITI Test (I))

Deviations:

yes

Remarks:

(test duration lower than 28 d)

GLP compliance:

no

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge (adaptation not specified)

Details on inoculum:

- Concentration of sludge: 30 mg/L

Duration of test (contact time):

2 wk

Initial conc.:

100 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

O2 consumption

Reference substance:

not specified

Key result

Parameter:

% degradation (O2 consumption)

Value:

84.6

Sampling time:

2 wk

Remarks on result:

other: Indirect analysis (BOD): 84.6%; Indirect analysis (TOC): 93%; Direct analysis (GC): 100%

Validity criteria fulfilled:

not specified

Interpretation of results:

readily biodegradable

Conclusions:

Under the test conditions, alpha terpineol was readily biodegradable.

Executive summary:

In a ready biodegradation study, alpha terpineol was tested at concentrations of 100 mg/L and the inoculum was activated sludge (30 mg/L). The degradation of the test material was assessed by the determination of the oxygen consumption. At 100 mg/L test concentration, 84.6% degradation (biochemical oxygen demand) was reached in 14 days. Under the test conditions, alpha terpineol was determined to be readily biodegradable.

Reference 3

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

weight of evidence

Justification for type of information:

REPORTING FORMAT FOR THE ANALOGUE APPROACH
The analogue substance alpha terpineol which shares the same functional groups with the substance L-alpha terpineol also has comparable values for the relevant molecular properties.
See attached the reporting format.

Reason / purpose for cross-reference:

read-across source

Key result

Parameter:

other: Maximum degradation rate (mg/L/h)

Value:

> 0.1

Sampling time:

94 h

Remarks on result:

other: Read across from an analogue from which a maximum degradation rate (mg/L/h) was <1 in 94 h in unacclimated soil-A extract

Details on results:

The detection of CO2, the increase in biomass concentration and lack of any substantial change in the concentration of terpene in the azide-amended control reactor demonstrated that biodegradation of alpha terpineol took place and that its disappearance was not the result for hydrolysis or any other physicochemical process (e.g., volatilization of the hydrocarbon monoterpenes).

Validity criteria fulfilled:

not applicable

Interpretation of results:

readily biodegradable

Conclusions:

Based on the read-across approach from the analogue alpha terpineol, laevo alpha terpineol can be considered to be readily degraded by cultures derived from forest soils.

Executive summary:

In a ready biodegradation study, alpha terpineol was tested at concentrations of 5 -40 mg/L. Forest-soil extract cultures were used as inocula. The degradation of the test material was assessed by the determination of the biomass, concentration of the test material and headspace CO2. The test treatments and control (sodium azide, 2.5 g/L) were measured in duplicates. The lack of any substantial change in alpha terpineol concentration in the azide-amended control reactor demonstrated that disappearance of the test item in the test reactor was not the result of hydrolysis or any other physicochemical process. Under the test conditions, alpha terpineol was readily degraded by cultures derived from forest soils. Based on these results, the read-across approach was applied and laevo alpha terpineol can be considered to be readily degraded by cultures derived from forest soils.

Reference 4

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

weight of evidence

Justification for type of information:

REPORTING FORMAT FOR THE ANALOGUE APPROACH
The analogue substance alpha terpineol which shares the same functional groups with the substance L-alpha terpineol also has comparable values for the relevant molecular properties.
See attached the reporting format.

Reason / purpose for cross-reference:

read-across source

Key result

Parameter:

% degradation (O2 consumption)

Value:

84.6

Sampling time:

2 wk

Remarks on result:

other: Read-across from an analogue for which the following results were obtained: Indirect analysis (BOD): 84.6%; Indirect analysis (TOC): 93%; Direct analysis (GC): 100%

Validity criteria fulfilled:

not applicable

Interpretation of results:

readily biodegradable

Conclusions:

Based on the read-across approach from the analogue alpha terpineol, laevo alpha terpineol can be considered ready biodegradable.

Executive summary:

In a ready biodegradation study, alpha terpineol was tested at concentrations of 100 mg/L and the inoculum was activated sludge (30 mg/L). The degradation of the test material was assessed by the determination of the oxygen consumption. At 100 mg/L test concentration, 84.6% degradation (biochemical oxygen demand) was reached in 14 days. Under the test conditions, alpha terpineol was determined to be readily biodegradable. Based on these results, the read-across approach was applied and laevo alpha terpineol can be considered to be readily biodegradable.

Description of key information

Weight of evidence: Read across approach: Japanese MITI test . Based on the read-across approach from the analogue alpha terpineol, laevo alpha terpineol can be considered ready biodegradable.

Weight of evidence: Read across approach: Aerobic biodegradation by forest-soil extract cultures. Based on the read-across approach from the analogue alpha terpineol, laevo alpha terpineol can be considered to be readily degraded by cultures derived from forest soils.

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Type of water:

freshwater

Additional information

Weight of evidence: Read across approach: In a ready biodegradation study performed similarly to OECD 301C guideline, alpha terpineol was tested at concentrations of 100 mg/L and the inoculum was activated sludge (30 mg/L). The degradation of the test material was assessed by the determination of the oxygen consumption. At 100 mg/L test concentration, 84.6% degradation (biochemical oxygen demand) was reached in 14 days. Under the test conditions, alpha terpineol was determined to be readily biodegradable. Based on these results, the read-across approach was applied and laevo alpha terpineol can be considered to be readily biodegradable.

Weight of evidence: Read across approach: In a ready biodegradation study, alpha terpineol was tested at concentrations of 5 -40 mg/L. Forest-soil extract cultures were used as inocula. The degradation of the test material was assessed by the determination of the biomass, concentration of the test material and headspace CO2. The test treatments and control (sodium azide, 2.5 g/L) were measured in duplicates. The lack of any substantial change in alpha terpineol concentration in the azide-amended control reactor demonstrated that disappearance of the test item in the test reactor was not the result of hydrolysis or any other physicochemical process. Under the test conditions, alpha terpineol was readily degraded by cultures derived from forest soils. Based on these results, the read-across approach was applied and laevo alpha terpineol can be considered to be readily degraded by cultures derived from forest soils.