Reaction mass of (3R,3aS,6R,7R,8aS)-3,6,8,8-tetramethyloctahydro-1H-3a,7-methanoazulen-6-yl rel-acetate and rel-(1aR,4aR,8aR)-2,4a,8,8-tetramethyl-1,1a,4,4a,5,6,7,8-octahydrocyclopropa[d]naphthalene and rel-(3R,3aS,7S,8aS)-3,6,8,8-tetramethyl-2,3,4,7,8,8a-hexahydro-1H-3a,7-methanoazulene

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

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

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: read-across from guideline studies

Justification for type of information:

The read across justification is presented in the Endpoint summary Biodegradation in water. The accompanying files are also attached there.

Reason / purpose for cross-reference:

read-across source

Reason / purpose for cross-reference:

read-across source

Key result

Parameter:

% degradation (O2 consumption)

Value:

73

Sampling time:

28 d

Remarks on result:

other: read-across from Cedryl acetate 'mono'

Key result

Parameter:

% degradation (O2 consumption)

Value:

68

Sampling time:

28 d

Remarks on result:

other: read-across from Longifolene Coeur

Interpretation of results:

readily biodegradable

Reference 2

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

16th of February 2016 until 17th of March 2016

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

In accordance with GLP

Justification for type of information:

This information is used for read across to Cedryl Acetate EOA

Qualifier:

according to guideline

Guideline:

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

Principles of method if other than guideline:

This test has been performed according to slightly modified EU, OECD and ISO Test Guidelines (OECD, 1992; EU, 1992; ISO, 1994).

GLP compliance:

yes

Oxygen conditions:

aerobic

Inoculum or test system:

natural water

Details on inoculum:

River water was sampled from the Rhine near Heveadorp, The Netherlands (11-02-2016). The nearest plant treating domestic wastewater biologically was 3 km upstream. The river water was aerated for 7 days before use to reduce the endogenous respiration (van Ginkel and Stroo, 1992). River water without particles was used as inoculum. The particles were removed by sedimentation after 1 day while moderately aerating.

Duration of test (contact time):

28 d

Initial conc.:

2 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

O2 consumption

Remarks:

as a percentage of ThOD

Details on study design:

Test bottles:
The test was performed in 0.30 L BOD (biological oxygen demand) bottles with glass stoppers.

Nutrients, stocks and administration:
The river water used in the Closed Bottle test was spiked per liter of water; 8.5 mg KH2PO4, 21.75 mg K2HPO4, 33.3 mg Na2HPO4·2H2O, 22.5 mg MgSO4·7H2O, 27.5 mg CaCl2, 0.25 mg FeCl3·6H2O. Ammonium chloride was omitted from the river water to prevent nitrification. Accurate administering of the test substance was accomplished by preparing a solid stock of 3.0 mg of the test substance per g of silica gel in a 50-mL serum flask. Only part of the top layer of the silica gel was brought into contact with the test substance. The serum flask was closed with a screw top with aluminium foil and the content was mixed vigorously. Subsequently 0.2 g of silica gel with the test substance was added to the test bottles. The resulting concentration of test substance in the bottles was 2.0 mg/L. Next the bottles were filled with nutrient medium with inoculum and closed. Sodium acetate was added to the bottles using a stock solution of 1.0 g/L.

Test procedure:
Use was made of 10 bottles containing only river water, 10 bottles containing river water and silica gel, 10 bottles containing river water and silica gel with test substance, 6 bottles with river water and sodium acetate. The concentrations of the test substance, and sodium acetate in the bottles were 2.0 and 6.7 mg/L, respectively. Each of the prepared solutions was dispensed into the respective group of BOD bottles so that all bottles were completely filled without air bubbles. The zero time bottles were immediately analyzed for dissolved oxygen using an oxygen electrode. The remaining bottles were closed and incubated in the dark. Two duplicate bottles of all series were withdrawn for analyses of the dissolved oxygen concentration at day 7, 14, 21, and 28.

Test conditions:
The pH of the media was 8.0 at the start of the test. The pH of the medium at day 28 was 7.9 (test) and 8.0 (controls). Temperatures were within the prescribed temperature range of 22 to 24°C.

Reference substance:

acetic acid, sodium salt

Remarks:

purity > 99%

Test performance:

The test is valid as shown by an endogenous respiration of 1.2 mg/L at day 28. Furthermore, the differences of the replicate values at day 28 were less than 20%. Sodium acetate was degraded by 88% of its theoretical oxygen demand after 14 days. Degradation of sodium acetate was not inhibited by the test substance. Finally, the most important criterion was met by oxygen concentrations >0.5 mg/L in all bottles during the test period.

Key result

Parameter:

% degradation (O2 consumption)

Value:

73

Sampling time:

28 d

Parameter:

% degradation (O2 consumption)

Value:

64

Sampling time:

21 d

Parameter:

% degradation (O2 consumption)

Value:

46

Sampling time:

14 d

Parameter:

% degradation (O2 consumption)

Value:

13

Sampling time:

7 d

Details on results:

The substance is biodegraded by 73% at day 28 in the Closed Bottle test. Over 60% biodegradation was achieved in a period of 14 days immediately following the attainment of 10% biodegradation. Cedryl acetate therefore fulfilled the 14-day time window (10-day time window for other OECD 301 tests) criterion for ready biodegradable compounds and hence Cedryl acetate should be classified as readily biodegradable.

Results with reference substance:

The biodegradation percentage of the reference compound, sodium acetate, at day 14 was 46.

Toxicity to inoculum:

Inhibition of the degradation of a well degradable compound e.g. sodium acetate by the test compound in the Closed Bottle test was not determined because possible toxicity of the Cedryl acetate monoconstituent to microorganisms degrading acetate is not relevant. Inhibition of the endogenous respiration of the inoculum by the test substance at day 7 was not detected. Therefore, no inhibition of the biodegradation due to the high initial concentration of the test compound is expected.

Table I Dissolved oxygen concentrations (mg/L) in the closed bottles.

Time (days)	Oxygen consumption (mg/L)		Biodegradation (%)
	Test substance	Acetate	Test substance	Acetate
0	0.0	0.0	0	0
7	0.7	4.1	13	76
14	2.6	4.6	46	85
21	3.6		64
28	4.1		73

Table II Oxygen consumption (mg/L) and the percentages biodegradation of the test substance, Cedryl acetate monoconstituent (BOD/ThOD) and sodium acetate (BOD/ThOD) in the Closed Bottle test

Time (days)	Oxygen consumption (mg/L)
	Ocs	Ot	Oc	Oa
0	8.8	8.8	8.8	8.8
	8.8	8.8	8.8	8.8
Mean (M)	8.8	8.8	8.8	8.8
7	8.2	7.6	8.2	4.0
	8.2	7.4	8.2	4.1
Mean (M)	8.2	7.5	8.2	4.1
14	8.1	5.5	8.2	3.6
	8.2	5.6	8.2	3.5
Mean (M)	8.2	5.6	8.2	3.6
21	7.8	4.1	7.6
	7.8	4.3	7.8
Mean (M)	7.8	4.2	7.7
28	7.4	3.3	7.5
	7.5	3.5	7.5
Mean (M)	7.5	3.4	7.5

OcsRiver water with nutrients and silica gel

OtRiver water with nutrients, test material (2.0 mg/L) and silica gel

OcRiver water with nutrients

OaRiver water with nutrients and sodium acetate (6.7 mg/L)

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable

Conclusions:

The substance is biodegraded by 73% at day 28 in the Closed Bottle test and should therefore be classified as readily biodegradable.

Executive summary:

In order to assess the biodegradation of Cedryl acetate, a screening test was performed according to OECD TG 301D (Closed Bottle test) and under GLP conditions. In this study river water was exposed to 2 mg/L of the substance for 28 days. Cedryl acetate did not cause a reduction in the endogenous respiration. Furthermore, the validity criteria of the test were met.

Cedryl acetate was biodegraded by 73% at day 28 in the standard Closed Bottle screening test. Over 60% biodegradation was achieved in a period of 14 days immediately following the attainment of 10% biodegradation and should therefore be classified as readily biodegradable. Cedryl acetate therefore fulfilled the 14-day time window (10-day time window for other OECD 301 tests) criterion for ready biodegradable compounds.

Reference 3

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

10 January 2017 - 08 February 2017

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Justification for type of information:

This information is used for read across to Cedryl Acetate EOA

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

1992

Qualifier:

equivalent or similar to guideline

Guideline:

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

Version / remarks:

1992

Qualifier:

equivalent or similar to guideline

Guideline:

ISO 10707 Water quality - Evaluation in an aqueous medium of the "ultimate" aerobic biodegradability of organic compounds - Method by analysis of biochemical oxygen demand (closed bottle test)

Version / remarks:

1994

GLP compliance:

yes (incl. QA statement)

Oxygen conditions:

aerobic

Inoculum or test system:

natural water

Details on inoculum:

River water was sampled from the Rhine near Heveadorp, The Netherlands. The river water was aerated for 7 days to reduce the endogenous respiration. River water without particles was used as inoculum. The particles were removed by sedimentation after 1 day while moderately aerating. The river water was spiked with mineral salts. Ammonium chloride was not added to the river water to prevent nitrification.

Duration of test (contact time):

28 d

Initial conc.:

2 mg/L

Based on:

test mat.

Remarks:

Coated on silica beads

Parameter followed for biodegradation estimation:

O2 consumption

Remarks:

as a percentage of ThOD

Details on study design:

Test bottles:
The test was performed in 0.30 L BOD (biological oxygen demand) bottles with glass stoppers.

Nutrients, stocks and administration:
The nutrient medium of the Closed Bottle test contained per liter of deionized water; 8.5 mg KH2PO4, 21.75 mg K2HPO4, 33.4 mg Na2HPO4·2H2O, 22.5 mg MgSO4·7H2O, 27.5 mg CaCl2, 0.25 mg FeCl3·6H2O. Ammonium chloride was not added to the river water to prevent nitrification. Accurate administering of the test substance was accomplished by preparing a solid stock of 3.0 mg of the test substance per g of silica gel in a 50-mL serum flask. Only part of the top layer of the silica gel was brought into contact with the test substance. The serum flask was closed with a screw top with aluminium foil and the content was mixed vigorously. Subsequently 0.2 g of silica gel with the test substance was added to the test bottles. The resulting concentration of test substance in the bottles was 2.0 mg/L. Next the bottles were filled with nutrient medium with inoculum and closed. Sodium acetate was added to the bottles using a stock solution of 1.0 g/L.

Test procedure:
Use was made of 10 bottles containing only river water, 10 bottles containing river water and silica gel, 10 bottles containing river water and silica gel with test substance, 6 bottles with river water and sodium acetate. The concentrations of the test substance, and sodium acetate in the bottles were 2.0 and 6.7 mg/L, respectively. Each of the prepared solutions was dispensed into the respective group of BOD bottles so that all bottles were completely filled without air bubbles. The zero time bottles were immediately analyzed for dissolved oxygen using an oxygen electrode. The remaining bottles were closed and incubated in the dark. Two duplicate bottles of all series were withdrawn for analyses of the dissolved oxygen concentration at day 7, 14, 21, and 28.

Test conditions:
The pH of the media was 8.0 at the start of the test. The pH of the medium at day 28 was 7.9 (test) and 8.0 (controls). Temperatures were within the prescribed temperature range of 22 to 24°C.

Reference substance:

acetic acid, sodium salt

Remarks:

purity > 99%

Test performance:

The test is valid as shown by an endogenous respiration of 1.4 mg/L at day 28. Furthermore, the differences of the replicate values at day 28 were less than 20%. Sodium acetate was degraded by 78% after 14 days. Finally, the oxygen concentrations were >0.5 mg/L in all bottles during the test period.

Key result

Parameter:

% degradation (O2 consumption)

Value:

68

Sampling time:

28 d

Details on results:

The substance is biodegraded by 68% at day 28 in the Closed Bottle test. The pass level of 60% in 28 days was obtained. The test substance is poorly water soluble (< 10 mg/l. The bioavailability of poorly water soluble substances does limit microbial growth . Therefore, poor water solubility is an important reason for not applying the 14 day time window (Battersby, 2000; Richterich and Steber, 2001). In addition, the substance contains more than one constituent and is considered a multi-constituent. This means that the substance can be classified as readily biodegradable only using the pass level of 60% at day 28.
Battersby NS (2000) The biodegradability and microbiological toxicity testing of lubricants
some recommendations. Chemosphere 41 1011-1027.
Richterich K and Steber J (2001) The time-window – an inadequate criterion for the ready
biodegradability assessment of technical surfactants. Chemosphere 44 1649-1654.

Results with reference substance:

The biodegradation of the reference compound, sodium acetate, at day 14 was 78%.

Toxicity to inoculum: No toxicity was seen in the study, because no inhibition of the oxygen consumption was seen in the test.

Table 1 Dissolved oxygen concentrations (mg/L) in the closed bottles.

Time (days)	Oxygen concentration (mg/L)
	Ocs	Ot	Oc	Oa
0	8.7	8.7	8.7	8.7
	8.7	8.7	8.7	8.7
Mean (M)	8.7	8.7	8.7	8.7
7	7.6	7.4	7.6	3.6
	7.7	7.1	7.6	3.7
Mean (M)	7.7	7.3	7.6	3.7
14	7.4	5.9	7.4	3.2
	7.5	6.0	7.4	3.2
Mean (M)	7.5	6.0	7.4	3.2
21	7.4	4.6	7.3
	7.3	4.8	7.4
Mean (M)	7.4	4.7	7.4
28	7.2	2.8	7.3
	7.2	2.6	7.3
Mean (M)	7.2	2.7	7.3

O_cs        River water with nutrients and silica gel.
O_t         River water with nutrients, test material (2.0 mg/L) and silica gel.

O_c         River water with nutrients.

O_a          River water with nutrients and sodium acetate (6.7 mg/L).

Table 2       Oxygen consumption (mg/L) and the percentages biodegradation of the test substance (BOD/ThOD) and sodium acetate (BOD/ThOD) in the Closed Bottle test.

Time (days)	Oxygen consumption (mg/L)		Biodegradation (%)
	Test substance	Acetate	Test substance	Acetate
0	0.0	0.0	0	0
7	0.4	3.9	6	72
14	1.5	4.2	23	78
21	2.7		41
28	4.5		68

Validity criteria fulfilled:

yes

Remarks:

Oxygen concentrations were >0.5 mg/L in all bottles during the test period, oxygen depletion in the inoculum blank was 1.4 mg dissolved oxygen/L, differences between replicates at day 28 were <20%, the test substance was assumed to be non inhibitory.

Interpretation of results:

readily biodegradable

Conclusions:

The substance is biodegraded by 68% at day 28 in the Closed Bottle test. In view of the substance containing one constituent and a few impurities the time window does not need to be met. In addition, the substance is considered to be poorly soluble (< 10 mg/l) and therefore the time window is not a good criterion for assessing the ready biodegradability. This means that based on the pass level of 60% at day 28, the test substance is classified as readily biodegradable.

Executive summary:

In order to assess the biodegradation of the test substance, the OECD TG 301D (Closed Bottle test) and under GLP conditions was performed. In this study river water was exposed to 2 mg/L of the substance for 28 days. The test substance did not cause a reduction in the endogenous respiration. Sodium acetate was used as reference item and was biodegraded for 78% at day 14. Furthermore, the validity criteria of the test were met. The substance is biodegraded by 68% at day 28 in the Closed Bottle test. In view of the substance containing one constituent and a few impurities the time window does not need to be met. In addition, the substance is considered to be poorly soluble (< 10 mg/l) and therefore the time window is not a good criterion for assessing the ready biodegradability. This means that based on the pass level of 60% at day 28, the test substance is classified as readily biodegradable.

Description of key information

Cedryl Acetate EOA is readily biodegradable based on read across from Cedryl Acetate 'mono' and from Longifolene Coeur which are both readily biodegradable in OECD TG 301D.

 

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Type of water:

freshwater

Additional information

The biodegradability in water of Cedryl Acetate EOA is based on read across from Cedryl Acetate 'mono' and Longifolene Coeur. The executive summary of the source information is presented first, followed by the read-across rationale.

Cedryl Acetate 'mono' biodegradability

For Cedryl Acetate 'mono', a biodegradation test was performed according to Closed Bottle test (OECD TG 301D, under GLP). In this study river water was exposed to 2 mg/L of the substance for 28 days. Cedryl Acetate 'mono' did not cause a reduction in the endogenous respiration. Furthermore, the validity criteria of the test were met. The substance was readily biodegraded, 73% degraded at day 28, fulfilled the 14 -day time window and is therefore readily biodegradable.

Longifolene Coeur biodegradability:

For Longifolene Coeur, a Closed Bottle test (OECD TG 301D, Rel 1) was performed. In this study river water was exposed to 2 mg/L of the substance for 28 days. The test substance did not cause a reduction in the endogenous respiration. Furthermore, the validity criteria of the test were met. The substance is biodegraded by 68% at day 28. The 14-day time window is not needed as a criterion because the substance contains several minor constituents (impurities). Therefore the substance is ready biodegradability.

Biodegradation of Cedryl Acetate EOA based on read across from data available for Cedryl Acetate ‘mono’ (CAS#77-54-3) and Longifolene Coeur (CAS# 475-20-7).

 

Introduction and hypothesis for the analogue approach

Cedryl acetate EOA consists of one major, two minor constituents and a number of impurities. All constituents have a hydrocarbon fused-ring system. Half of the constituents have an acetate attached to this ring the other half does not have this ester group. The constituents are sub-grouped into two main types: Cedryl acetate-type and Longifolene Coeur-type (hydrocarbon-fused-ring-type).

ForCedryl Acetate EOAthere are no experimentalbiodegradationdata available.In accordance with Article 13 of REACH, lacking information can be generated by means other than experimental testing, i.e. QSARs, grouping and read-across.For assessing thebiodegradationofCedryl Acetate EOA, the analogue approach is selected because for the main constituent, Cedryl Acetate ‘mono’, and for the close structural analogue Longifolene Coeur,experimental data isavailable which can be used for read across.

Hypothesis: Cedryl Acetate EOA is readily biodegradable because one key constituent representing half of Cedryl Acetate EOA is readily biodegradable. The other half of Cedryl Acetate EOA is also readily biodegradable because an analogue Longifolene Coeur, representing this half, is also readily biodegradable.

Available information:

For Cedryl Acetate ‘mono’a Closed Bottle test (OECD TG 301D, Rel. 1) is available, which shows that this substance is readily biodegradable. In this study river water was exposed to 2 mg/L of the substance for 28 days. It was biodegraded by 73% at day 28 and the 14-d window was met.For Longifolene Coeura Closed Bottle test (OECD TG 301D, Rel. 1) is available, a study was performed according to OECD TG 301D (Closed Bottle Test), which shows that this substance is readily biodegradable. Longifolene Coeur was biodegraded by 68% at day 28.

Target chemical and source chemical(s)

Chemical structures of the target chemical and the source chemical(s) are shown in the data matrix, including physico-chemical properties and available environmental fate information.

Purity / Impurities

The unidentified impurities of Cedryl Acetate EOA are not considered to influence the biodegradation potential of the substance.

Analogue approach justification

According to Annex XI 1.5 read across can be used to replace testing when the similarity can be based on a common backbone and a common functional group. When using read across the result derived should be applicable for C&L and/or risk assessment and it should be presented with adequate and reliable documentation, which is presented below.

Analogue selection: Cedryl Acetate ‘mono’ and Longifolene Coeurwere selected as source chemicals for read-across as they are considered representatives for two sub-groups of constituents of Cedryl Acetate EOA, based on their structures and functional groups.

Structural similarities and differences:

Cedryl Acetate EOA components (constituents and impurities) all have a hydrocarbon fused-ring system similar to Cedryl Acetate ‘mono’ and Longifolene Coeur. All components are multi-methylated with 3-5 methyl groups attached at varying positions. The constituents are sub-grouped into two main types: Cedryl acetate-type and Longifolene Coeur-type (solely hydrocarbon-fused-ring-type). The first one has an ester functionality which is absent in the second one.

Bioavailability:Bioavailability will be similar between the Cedryl acetate EOA components in view of log Kow of >=5.

Biodegradable fragments: In view of the similarity in structures the biodegradable fragments will also be similar. Experimentally it shows that both substances with and without the acetate group are readily biodegradable and therefore this does not affect the prediction. BIOWIN (v.4.10) is used to show the similarity of the fragments in the constituents (Table 1).

 

Table 1: Overview of BIOWIN identified structure fragments per constituent and predicted BIOWIN 5 and BIOWIN 6 scores

Biowin Fragment	Cedryl acetate type		Hydrocabon-fused-ring type
	77-54-3		32435-95-3	22567-43-7	65450-98-8	51773-81-0	475-20-7
Ester [-C(=O)-O-C]	1	1	--	--	--	--	--
Carbon: 4 single bonds, no hydrogens	3	2	3	2	2	2	2
Methyl [-CH3]	5	5	4	4	3	3	3
-CH2- [cyclic]	5	6	5	4	5	3	5
-CH- [cyclic]	3	1	1	3	3	--	3
-C=CH [alkenyl hydrogen]	--	--	1	1	2	--	2
Aromatic-CH3	--	--	--	--	--	1	--
Aromatic-H	--	--	--	--	--	4	--
BIOWIN 5 result	0.6101	0.5373	0.4259	0.3635	0.3890	0.3802	0.3890
BIOWIN 6 result	0.3605	0.3831	0.2655	0.1288	0.1589	0.2765	0.1589

 

Also, it can be seen that the deviation in the number of fragments between the different constituents is limited. The prediction as such of this model is not used because experimental information is present.

Uncertainty of the prediction: There are no additional uncertainties other than presented above.

Data matrix

The relevant information on physico-chemical properties and environmental fate properties are presented in the data matrix below.

Conclusions for environmental fate

For Cedryl Acetate EOA no biodegradation information is available. Its biodegradation potential can be derived from Cedryl Acetate ‘mono’ and Longifolene Coeur, which are both readily biodegradable and therefore Cedryl Acetate EOA will be assessed as readily biodegradable as well.

 

Data matrix to support the read across to Cedryl acetate EOA from Cedryl acetate and Longifolene Coeur for biodegradability

Common names	Cedryl Acetate EOA							Cedryl acetate	Longifolene Coeur
	Target	Target	Target	Target	Target	Target	Target	Source	Supporting source
	Cedryl Acetate type			Longifolene type
Chemical structures
Typical concentration (%)	30-45 (major)	<10	<10	15-30 (minor)	8-16 (minor)	<10	<10
CAS no				32435-95-3	22567-43-7			77-54-3	475-20-7
Einecs	944-520-4							201-036-1	207-491-2
REACH	2018	2018						2018	2018
Smiles								O=C(OC(C(CC(C1CC2) (C2C)C3)C1(C)C)(C3)C)C	C(C(C(C1=C)C2)C(CCC3) (C)C)(C13C)C2
Molecular weight	264	264	264	204	204	204	202	264	204
Phys-Chem data*
Log Kow	5.33	5.33	5.94	6.12	5.74	5.82	6.19	5.33 (6 exp.)	5.48 (5 exp.)
Fate
Ready biodegradability	Readily biodegradable (Read across)	Readily biodegradable (Read across)	Readily biodegradable (Read across)	Readily biodegradable (Read across)	Readily biodegradable (Read across)	Readily biodegradable (RA)	Readily biodegradable (RA)	Readily biodegradable (OECD TG 301D)	Readily biodegradable (OECD TG 301D)

**Physico-chemical properties are calculated with EpiSuite; RA=Read across