Reaction mass of (1S*, 2R*, 5S*)-2-Isopropenyl-5-methylcyclohexanol and (1S*, 2S*, 5R*)-2-Isopropenyl-5-methylcyclohexanol

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:

09 Aug - 06 Sep 2000

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EU Method C.4-E (Determination of the "Ready" Biodegradability - Closed Bottle Test)

GLP compliance:

yes

Oxygen conditions:

aerobic

Inoculum or test system:

other: Secondary effluent of a domestic sewage treatment plant

Details on inoculum:

- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure): Secondary effluent was collected at "Kläranlage Odenthal", Germany on 04 Aug 2000.
- Pretreatment: Coarse particles were separated by filtration; aeration of mineral medium plus inoculum for 5 d

Duration of test (contact time):

28 d

Initial conc.:

2.9 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

TEST CONDITIONS
- Composition of medium: according to guideline
- Test temperature: 20 ± 1 °C
- Continuous darkness: yes

TEST SYSTEM
- Number of culture flasks/concentration: 2
- Test performed in closed vessels due to significant volatility of test substance: yes (completely full and closed bottles)
- Test performed in open system: no

SAMPLING
- Sampling frequency: Dissolved oxygen was measured after 0, 7, 14, 21 and 28 d

CONTROL AND BLANK SYSTEM
- Inoculum blank: yes, 2 bottles
- Abiotic sterile control: no
- Toxicity control: yes, 2 bottles
- Other: reference subtance: yes, 2 bottles

Reference substance:

benzoic acid, sodium salt

Key result

Parameter:

% degradation (O2 consumption)

Value:

73

Sampling time:

28 d

Remarks on result:

other: Mean of two replicates.

Results with reference substance:

The reference substance showed 76% (mean) degradation after 14 days and was degraded to 89% (mean) after 28 d.

Table 1: Degradation of the test item, the toxicity control and the reference item during exposure

	% degradation of the test item
	7 d	14 d	21 d	28 d
Bottle 1	4	57	63	64
Bottle 2	5	63	74	82
Mean	5	60	69	73
	% degradation in toxicity control
Bottle 1	33	58	76	76
Bottle 2	28	59	77	76
Mean	31	59	77	76
	% degradation of reference substance
Bottle 1	69	77	79	85
Bottle 2	66	75	84	86
Mean	68	76	82	86

The test item is not inhibitory to the inoculum based on the results from the toxicity control.

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable

Conclusions:

Readily biodegradable: 73% after 28 d (O2 consumption, EU Method C.4-E: Closed Bottle Test)

Description of key information

Readily biodegradable: 73% after 28 d (O2 consumption, EU Method C.4 -E: Closed Bottle Test)

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Additional information

One experimental study is available investigating the biodegradation of the test item according to EU Method C.4 -E: Closed Bottle Test under GLP conditions (2000). A closed bottle test was performed for this substance due to volatility (vapour pressure: 100 Pa at 20 °C). Secondary effluent from a domestic sewage treatment plant was used as inoculum. 2.9 mg/L of the test item was applied to the test vessels and biodegradation was recorded over a period of 28 d. After 28 d the substance was degraded to 73% based on O2 consumption. In conclusion, the substance is readily biodegradable according to the OECD criteria. A toxicity control containing both, test substance and reference substance, did not indicate any toxic effects of the test item (76% degradation after 28 d).

[Type of water: freshwater]