Octahydro-4,7-methano-1H-inden-5-yl acetate

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:

key study

Study period:

22/01/1996-27/02/1996

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: The study was conducted according to OECD TG 301F in compliance with GLP, without deviations that influence the quality of the results.

Justification for type of information:

The information is used for read across to Cyclacet Dihydro.

Reason / purpose for cross-reference:

read-across: supporting information

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 F (Ready Biodegradability: Manometric Respirometry Test)

Deviations:

no

GLP compliance:

yes

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

Fresh activated sludge from a biological waste water treatment plant treating predominantly domestic sewage (City of Geneva, Aire) was used.
The sludge is collected in the morning, washed three times in the mineral medium (by centrifuging at 1000 g for 10 minutes, discarding the supernatant and resuspending in mineral medium) and kept aerobic until being used on the same day.
- Concentration of sludge: dry weight of suspended solids: 4.919 g/l

Duration of test (contact time):

28 d

Initial conc.:

100 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

TEST CONDITIONS
- Composition of medium: The water used during this study is deionised water containing less than 10 mg/l dissolved organic carbon. The medium was prepared according to the method mentioned in the guidance.
- Test temperature: 22°C
- pH: 7.36-8.30
- pH adjusted: yes, where necessary at the start of the test to pH 7.4 +/- 0.2 with phosphoric acid or potassium hydroxide
- Suspended solids concentration: 30 mg/l (dry weight)

TEST SYSTEM
- Culturing apparatus: The respirometer used during this study is a SAPROMAT D 12, made by J. M. VOITH GmbH, D-7920 Heidenheim.
- Number of culture flasks/concentration: 2
- Details of trap for CO2 and volatile organics if used: About 2 g of soda lime was placed in an attachment of the stopper.

SAMPLING
Sampling of test concentrations not reported.
Everyday the oxygen consumption of each flask is recorded and correct temperature and stirring are checked.
At the end of the test period (normally 28 days), the pH of each flask is measured again.

CONTROL AND BLANK SYSTEM
- Inoculum blank: yes, 2 replicates containing inoculum but no test substance or reference substance
- Toxicity control: A pair of flasks of the volumetric respirometer (SAPROMAT) are filled with: mineral medium + test chemical (100 mg/l) + aniline
(100 mg/l) + inoculum
- Other: Reference substance control containing mineral medium + aniline (100 mg/l) + inoculum

Reference substance:

aniline

Remarks:

Merck, Darmstadt, Germany, Art. No. 1261, Purity min. 99.5%

Preliminary study:

Not relevant

Test performance:

The curve obtained with Aniline alone and with VERDYL ACETATE + Aniline showed no toxic effects of VERDYL ACETATE on the micro-organisms at the test concentration.

Key result

Parameter:

% degradation (O2 consumption)

Value:

10

Sampling time:

28 d

Remarks on result:

other: Mean of 2 flasks

Details on results:

Details on measured test substance concentrations, pH and the measured BOD values and corresponding % degradation are included in the overall remarks. The biodegradation curve is included as attached background material.

Results with reference substance:

The degradation of aniline was >40% after 7 days (79%) and >65% after 14 days (85%).

Actual concentrations and pH:

Flask No.	Concentrations (mg/l		pH
	Test substance	Reference substance	Initial	Final
2/1	0	101.6	7.47	8.30
2/2	0	103.0	7.40	8.20
2/3	0	0	7.40	7.56
2/4	0	0	7.37	7.36
2/5	100.8	0	7.37	7.45
2/6	103.4	0	7.37	7.36
2/7	100.7	104.0	7.38	8.13
2/8	105.3	102.7	7.43	8.27

Biological Oxygen Demand (BOD, mg 02/l, adjusted to nominal concentrations):

		Days:	5	7	10	14	21	28
BOD Sludge	1^stflask	B1	20.0	23.0	26.0	28.0	31.0	33.0
	2^ndflask	B2	21.0	24.0	28.0	31.0	36.0	39.0
	Mean	B	20.5	23.5	27.0	29.5	33.0	36.0
BOD Test Subst.	1^stflask	C1	42.8	45.8	49.8	53.8	58.8	60.8
	2^ndflask	C2	39.4	44.3	49.2	53.2	57.2	59.2
	1^stfl. corr.	C1-B	22.3	22.3	22.8	24.3	25.3	24.8
	2^ndfl. corr.	C2-B	18.9	20.8	22.2	23.7	23.7	23.2
% degr.	1^stflask	D1	9	9	9	10	10	10
	2^ndflask	D2	8	8	9	9	9	9
	Mean	D	8	9	9	10	10	10

B = (B1 + B2) / 2

D1 = 100 * (C1 -B) / ThOD * [S]                                   [S]: Initial test substance concentration (mg/l)

D2 = 100 * (C2 - B) / ThOD * [S]

D = (D1 + D2) / 2

Validity criteria fulfilled:

yes

Remarks:

oxygen uptake of inoculum blank <60 mg/l, difference between replicates <20%, in toxicity control showed no inhibition of biodegradation of reference substance by test substance

Interpretation of results:

other: Not readily biodegradable

Conclusions:

VERDYL ACETATE undergoes only 10 % biodegradation after 28 days in the test conditions.
Thus, VERDYL ACETATE should be regarded as not readily biodegradable under the conditions in this test.

Executive summary:

The Ready Biodegradability of Cyclacet was determined by the Manometric Respirometry Test according to the OECD Guidelines for Testing of Chemicals, Method No. 301 F. The concentration tested was 100 mg/l substance, with an activated sludge concentration of 30 mg/l. The validity criteria for the test were met. The substance undergoes 10 % biodegradation after 28 days in the test conditions. Therefore the substance should be regarded as not readily biodegradable under the conditions in this test.

Reference 2

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: The value is derived based on read across

Justification for type of information:

Cyclacet Dihydro will have the same biodegradation potential (10%) as Cyclacet in view of high similarity in structure: backbone and functional group, resulting in the same non-ready biodegradability.
Structural similarities and differences: Cyclacet Dihydro, the target, and the source chemical Cyclacet have identical structural features consisting of a tricyclodecan-e/yl fused ring structure and an acetic ester attached at the bridged hexyl ring. The difference is that Cyclacet Dihydro (as presented in the name) does not have a double bond in the 5-ring which Cyclacet has.
Bioavailability: The molecular weight, appearance, physic-chemical properties all indicate a similar bioavailability and as such will not be different between these two.
Biodegradation: Primary biodegradation will start by cleaving the ester-bond resulting in acetic acid and the tricyclodecan/yl/al fused ring with an alcohol group on where the ester bond was cleaved (Wheelock et al., 2008). The 10% biodegradation reflects the degradation of this acetic ester. The tricylodecan-e/-yl ring will be more resistant to biodegradation. The double bond in the pentyl-ring is not anticipated to make a difference in the biodegradation.
Uncertainty: There is no uncertainty in the prediction based on the same functional group and very similar backbone. This is expressed also in BIOWIN 5 and 6 predictions. For Cyclacet Dihydro have ready biodegradability probability of 0.64 and 0.48, respectively, while Cyclacet has 0.62 and 0.39, respectively.

Reason / purpose for cross-reference:

read-across source

Key result

Parameter:

% degradation (CO2 evolution)

Value:

10

Sampling time:

28 d

Remarks on result:

other: Not ready biodegradable

Executive summary:

Cyclacet Dihydro has the same biodegradation potential (10%) as Cyclacet in view of high similarity in structure: backbone and functional group, resulting in the same non-ready biodegradability.Structural similarities and differences:Cyclacet Dihydro, the target, and the source chemical Cyclacet have identical structural features consisting of a tricyclodecan-e/-yl, respectively, fused ring structure and an acetic ester attached at the bridged hexyl ring. The difference is that Cyclacet Dihydro (as presented in the name) does not have a double bond in the 5-ring which Cyclacet has.

Bioavailability: The molecular weight, appearance, physic-chemical properties all indicate a similar bioavailability and as such will not be different between these two.

Biodegradation potential: Primary biodegradation will start by cleaving the ester-bond resulting in acetic acid and the tricyclodecan-e/-yl fused ring with an alcohol group on where the ester bond was cleaved, based on the abundancy of carboxyl-esterases (Wheelock et al., 2008). The 10% biodegradation reflects the degradation of this acetic ester. The tricylodecan-e/-yl will be more resistant to biodegradation. The double bond in the pentyl-ring is not anticipated to make a difference in the biodegradation.

Uncertainty: There is no uncertainty in the prediction based on the same functional group and very similar backbone. This is expressed also in BIOWIN 5 and 6 predictions. For Cyclacet Dihydro have ready biodegradability probability of 0.64 and 0.48, respectively, while Cyclacet has 0.62 and 0.39, respectively. If anything Cyclacet Dihydro might be more biodegradable compared to Cyclacet.

Description of key information

The substance, using read across from Cyclacet, is not considered ready biodegradable.

Key value for chemical safety assessment

Biodegradation in water:

under test conditions no biodegradation observed

Additional information

For the substance no information is available on ready biodegradability. Therefore read across is used from the close analogue Cyclacet. First the ready biodegradation information from Cyclacet is presented and thereafter the read across justification

Cyclacet Dihydro (Cas no 64001-15-6)and its biodegradation potential derived from Cyclacet (Cas no generic 54830-99-8)

Cyclacet Dihydro has atricyclodecan-e/-yl fused ring structure to which an acetic-ester is attached (Fig. 1 and data matrix). For this substance no ready biodegradability information is available. In accordance with Article 13 of REACH, lacking information can be generated by means of applying alternative methods such as QSARs, grouping and read-across. For Cyclacet Dihydro the ready biodegradability will be derived from Cyclacet

Hypothesis: Cyclacet Dihydro will have the same biodegradation potential (10%) as Cyclacet in view of high similarity in structure: backbone and functional group, resulting in the same non-ready biodegradability.

Available experimental information: For Cyclacet a reliable OECD TG 301F study is available (GLP and Klimisch 1) in which a biodegradation of 10% was achieved.

Target chemical and source chemical(s)

Chemical structures of the target chemical and the source chemical are shown in the data matrix

Purity / Impurities

The purity and impurities of the target chemical do not indicate other constituents or impurities (all< 10%) that indicated a different biodegradation potential.

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.

In accordance with ECHA guidance (2017, RAAF) Cyclacet is selected as the key source because of the similarities in structure of both substances considering backbone and functional group.

Structural similarities and differences:Cyclacet Dihydro, the target, and the source chemical Cyclacet have identical structural features consisting of a tricyclodecan-e/yl fused ring structure and an acetic ester attached at the bridged hexyl ring. The difference is that Cyclacet Dihydro (as presented in the name) does not have a double bond in the 5-ring which Cyclacet has.

Bioavailability: The molecular weight, appearance, physico-chemical properties all indicate a similar bioavailability and as such will not be different between these two.

Biodegradation: Primary biodegradation will start by cleaving the ester-bond resulting in acetic acid and the tricyclodecan/yl/al fused ring with an alcohol group on where the ester bond was cleaved (Wheelock et al., 2008). The 10% biodegradation reflects the degradation of this acetic ester. The tricylodecan-e/-yl ring will be more resistant to biodegradation. The double bond in the pentyl-ring is not anticipated to make a difference in the biodegradation.

Uncertainty: There is no uncertainty in the prediction based on the same functional group and very similar backbone. This is expressed also in BIOWIN 5 and 6 predictions. For Cyclacet Dihydro have ready biodegradability probability of 0.64 and 0.48, respectively, while Cyclacet has 0.62 and 0.39, respectively. In accordance with ECHA guidance (RAAF, 2017) the read across receives score 5.

Data matrix

See Table at the end of the section.

Conclusions for environmental fate and classification and labelling

Fate: Cyclacet is non-ready biodegradable and therefore Cyclacet Dihydro is not ready biodegradable using read across from Cyclacet

Classification and Labelling: Cyclacet Dihydro is considered not ready biodegradable. 

 

Table 1: Data matrix presenting the characteristics of Cyclacet Dihydro and its source Cyclacet to support the read across for biodegradation

Common names	Cyclacet Dihydro	Cyclacet
Chemical structures
	Target	Source
Cas no of the main isomer Cas no of the generic	64001-15-6	2500-83-6 (5-yl) 54830-99-8
Einecs	264-598-7	911-369-0
REACH registration	REACH registered for 2018	REACH registered
Empirical formula	C12H18O2	C12H16O2
Smiles	CC(=O)OC3CC1CC3C2CCCC12	CC(=O)OC3CC1CC3C2CC=CC12
Physico-chemical data
Molecular weight	194	192
Physical state	liquid	liquid
Vapour pressure Pa (measured)	2.2	2.1
Water solubility mg/l (measured)	89	186
Log Kow (measured)	4.5	3.9
Log Kow (calculated – ECOSAR)	3.1	2.85
Fate
Biodegradability % Readily Biodegradable	Read across from Cyclacet	10 No

 

References

Wheelock, C.E., Philips, B.M., Anderson, B.S., Miller, J.L., Miller, M.J., and Hammock, B.D., 2008, Application of carboxylesterase activity in environmental monitoring and toxicity identification evaluations, (TIEs), in Reviews of Environmental Contamination an Toxicology, ed. Whitacre, 117-178, D.M., Springer.