Reaction mass of (4R)-isopropenyl-1-methylcyclohexene and (4S)-isopropenyl-1-methylcyclohexene and 1-isopropyl-4-methylcyclohexa-1,3-diene and 1-isopropyl-4-methylcyclohexa-1,4-diene and 4-isopropylidene-1-methylcyclohexene

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:

11 February to 10 March 2016

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

GLP study performed according to OECD Guideline No. 301 D. All validity criteria were fulfilled

Reason / purpose for cross-reference:

reference to same study

Reason / purpose for cross-reference:

reference to other study

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

Principles of method if other than guideline:

Not applicable

GLP compliance:

yes (incl. QA statement)

Remarks:

05 March 2015

Oxygen conditions:

aerobic

Inoculum or test system:

other: river water

Details on inoculum:

- Origin: River water was sampled from “L’Adour”, situated downstream of a plant treating domestic wastewater (Aureilhan, France).
- Pre-conditioning: The river water was aerated for about 7 days before use as inoculum at the test temperature to reduce endogenous respiration.

Duration of test (contact time):

28 d

Initial conc.:

2 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

TEST CONDITIONS
- Test water: Mineral medium, Reconstituted water, as prescribed by the OECD Guideline No. 301D
- Composition of medium: Mineral medium (8.5 mg KH2PO4, 21.75 mg K2HPO4, 33.40 mg Na2HPO4•2H2O, 0.50 mg NH4Cl; 36.40 mg CaCl2•2H2O, 22.50 mg MgSO4•7H2O and 0.25 mg FeCl3•6H2O.)
- River water was aerated for about 7 days before use as inoculum at the test temperature to reduce endogenous respiration.
- Test temperature: 21.1-22.1 °C throughout the test (average value: 21.8 °C)
- Continuous darkness: Yes

TEST SYSTEM
- Culturing apparatus: All-glass sealed with ground glass stoppers BOD (Biological Oxygen Demand) bottles of approximately 300 mL capacity.
- Inoculum: A concentration of inoculum of approximately 10^5 cells/L was used.
- Number of culture flasks/concentration: 10 bottles containing test item, inoculum, mineral medium and silica gel (test suspension)

SAMPLING
- Sampling frequency: Determinations of the concentration of dissolved oxygen using an oxygen electrode in duplicate vessels taken from each group (except the procedure control) were made at day 0, 7, 14, 21 and 28, and only at the start of the test and after 7 and 14 days of incubation for the procedure control.
- Temperature: Measured continuously in the growth chamber.

CONTROL AND BLANK SYSTEM
- Inoculum blank: 10 bottles containing inoculum, mineral medium and silica gel (inoculum blank + with silica gel); 10 bottles containing inoculum and mineral medium (inoculum blank without silica gel)
- Procedure control: 6 bottles containing reference substance, inoculum and mineral medium (procedure control)
- Toxicity control: No

Reference substance:

benzoic acid, sodium salt

Remarks:

2 mg/L

Preliminary study:

None

Key result

Parameter:

% degradation (O2 consumption)

Value:

87

Sampling time:

28 d

Details on results:

Test item was biodegraded by 87 % at day 28 in the Closed Bottle test. Substances are considered to be readily biodegradable in this test if oxygen consumption is equal to or greater than 60 % of the ThOD value within ten days from the day by which the level exceeding 10 %, and this pass level is attained within 28 days. In this study, the pass level of 60 % was reached after less than 7 days (approximately 5 days) upon achieving 10 % biodegradation. The test item therefore fulfilled the 10-day time window criterion for ready biodegradable compounds.
Calculated ThOD of the test item: 3.29 mg O2/mg

Results with reference substance:

Calculated ThOD of the reference substance: 1.67 mg O2/mg. The biodegradation percentage of the reference substance, sodium benzoate, was 73 % at day 14.

Table 5.2.1/1: Percentage biodegradation of the test item and of the reference substance throughout the test

 

Test item and of the reference substance	Replicates	Time (days)
		0	7	14	21	28
Test Suspension (2 mg/L)	Replicate 1	0.00	60.49	77.20	83.21	85.26
	Replicate 2	0.00	75.38	79.48	82.45	88.30
	Mean	0	68	78	83	87
Procedure Control (2 mg reference substance/L)	Replicate 1	0.00	77.10	71.11	N.A.	N.A.
	Replicate 2	0.00	78.59	75.60	N.A.	N.A.
	Mean	0	78	73	N.A.	N.A.

Validity criteria of the test:      

Inoculum blank: Oxygen depletion in the inoculum blank did not exceed 1.5 mg dissolved oxygen/L after 28 days.

Residual [O₂]: Oxygen concentrations were > 0.5 mg/L in all bottles during the test period.

Replicate values: The differences of the replicate (test suspension) values at day 28 were less than 20 %.

Reference substance: The biodegradation percentage of the reference substance, sodium benzoate, was 73 % at day 14.

Thus all validity criteria of the test have been fulfilled in the present study.

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable

Conclusions:

Test item REACTION MASS OF DL-LIMONENE, ALPHA- GAMMA- TERPINENES, TERPINOLENE is considered as readily biodegradable based on the biodegradation percentage of 87% at day 28 and fulfilling the 10 days time window requirement (ca. less than 7 days).

Executive summary:

A ready biodegradability study was performed to assess the biotic degradation of test item REACTION MASS OF DL-LIMONENE, ALPHA- GAMMA- TERPINENES, TERPINOLENE according to OECD Guideline 301 D and in compliance with GLP.

Ten BOD bottles were filled with mineral medium inoculated with river water (5 mL/L) and test item was added at a nominal concentration of 2 mg/L with the help of silica gel. In the meantime, two series of ten blanks (with and without silica gel) were filled with inoculated mineral medium. Furthermore, six bottles containing reference substance sodium benzoate (2 mg/L) were tested in order to check the procedure. The concentrations of dissolved oxygen in duplicate bottles from each group incubated at 22 ± 2°C in darkness were measured at the start of the test and thereafter once a week until the end of the test (28 days for each group except the procedure control until 14 days).

The validity of the test was demonstrated by an endogenous respiration < 1.5 mg O2/L and by a biodegradation of the reference substance of 73% of its ThOD after 14 days of incubation. Moreover, the differences of the replicate values at day 28 were less than 20% and oxygen concentrations were > 0.5 mg/L in all bottles during the test period. The test item was biodegraded by 87% at day 28. Substances are considered to be readily biodegradable in the Closed Bottle test if oxygen consumption is equal to or greater than 60% of the ThOD value within ten days from the day by which the level exceeding 10% and this pass level is attained within 28 days. In this study, the pass level of 60% was reached after less than 7 days (approximately 5 days) upon achieving 10% biodegradation.

Therefore, the test item is considered as readily biodegradable based on the biodegradation percentage of 87% at day 28 and fulfilling the 10 days time window requirement (ca. less than 7 days).

Description of key information

Test item REACTION MASS OF DL-LIMONENE, ALPHA- GAMMA- TERPINENES, TERPINOLENE is readily biodegradable according to the criteria of guideline OECD 301 D.

The test item was biodegraded by 87% at day 28. The pass level of 60% was reached after less than 7 days (approximately 5 days) upon achieving 10% biodegradation.

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Additional information

A ready biodegradability study was performed to assess the biotic degradation of test item REACTION MASS OF DL-LIMONENE, ALPHA- GAMMA- TERPINENES, TERPINOLENE according to OECD Guideline 301 D and in compliance with GLP.

The validity of the test was demonstrated by an endogenous respiration < 1.5 mg O2/L and by a biodegradation of the reference substance of 73% of its ThOD after 14 days of incubation. Moreover, the differences of the replicate values at day 28 were less than 20% and oxygen concentrations were > 0.5 mg/L in all bottles during the test period. The test item was biodegraded by 87% at day 28. Substances are considered to be readily biodegradable in the Closed Bottle test if oxygen consumption is equal to or greater than 60% of the ThOD value within ten days from the day by which the level exceeding 10% and this pass level is attained within 28 days. The pass level of 60% was reached after less than 7 days (approximately 5 days) upon achieving 10% biodegradation.

The test item is considered as readily biodegradable based on the biodegradation percentage of 87% at day 28 and fulfilling the 10 days time window requirement (ca. less than 7 days).