2,6-dimethyloctan-2-ol

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:

10 October - 7 November 2000

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

No CoA, no clarity on meeting time window of 14 days for a CBT, only SOP numbers are given but no summary provided

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

GLP compliance:

yes

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

Secondary effluent of a domestic sewage treatment plant, collected 6 Oct 2000, (Kläranlage Odenthal). The effluent was preconditioned by seperation of coarse particles by filtration and aeration of mineral medium plus inoculum (filtrate) for 4 days.
The effluent concentration in the reaction mixture was 5 ml/L

Duration of test (contact time):

28 d

Initial conc.:

2.3 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

Reference is made to SOPs, no summary description available.
Incubation temperature was 20 +/- 1 C

Reference substance:

benzoic acid, sodium salt

Remarks:

at 2.9 mg/L

Test performance:

Test was considered acceptable as all validity criteria were met.

Key result

Parameter:

% degradation (O2 consumption)

Value:

72

Sampling time:

28 d

Parameter:

% degradation (O2 consumption)

Value:

66

Sampling time:

21 d

Parameter:

% degradation (O2 consumption)

Value:

56

Sampling time:

14 d

Parameter:

% degradation (O2 consumption)

Value:

35

Sampling time:

7 d

Results with reference substance:

The reference substance showed 80% degradation after 14 days.

Name	Substance	% degradation 7 d	% degradation 14 d	% degradation 21 d	% degradation 28 d
Test substance	Tetrahydro-myrcenol (THM)	35	56	66	72
Reference substance	Sodium benzoate (SB)	67	80	82	84
Toxicity control	THM & SB	42	59	68	66

The following criteria were met: The reference substance was degradaed >60% (80%) in 14 days; No toxicity of the test substance was observed in the toxicity control; The difference of the extremes of the replicates at the end of the test is less than 20%; Oxygen depletion in the inoculum blank did not exceed 1.5 mg/L dissoved oxygen after 28 days and residual oxygen concentrations in the test bottles were > 0.5 mg/L at all times.

Validity criteria fulfilled:

yes

Remarks:

The reference substance, toxicity of the test substance, the difference of the replicates at 28d, O2 depletion (inoculum blank) and residual O2 conc in the test bottles met the validity criteria.

Interpretation of results:

readily biodegradable

Conclusions:

The substance showed 72% biodegradation in an OECD TG 301D test meeting the 14-day time window and is considered to be readily biodegradable.

Executive summary:

The ready biodegradability of Tetrahydromyrcenol was investigated in a study conducted in accordance with OECD TG 301D (closed bottle test) and GLP. The concentration tested was 2.3 mg/l test substance, with a secondary effluent concentration of 5 mg/l. There was 80% biodegradation of the reference substance sodium benzoate at 14 d. A toxicity control was included not showing toxicity of the test substance. The test substance biodegrades for 72% meeting the 14-day time window.

Description of key information

The ready biodegradability of Tetrahydromyrcenol was investigated in a study conducted in accordance with OECD TG 301D (closed bottle test) and GLP. The concentration tested was 2.3 mg/l test substance, with a secondary effluent concentration of 5 mg/l. There was 80% biodegradation of the reference substance sodium benzoate at 14 d. A toxicity control was included not showing toxicity of the test substance. The test substance biodegrades for 72% meeting the 14-day time window.

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable