5,9-dimethyl-4,8-decadienal

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:

16 March 2011 - 13 April 2011

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Reason / purpose for cross-reference:

read-across: supporting information

Qualifier:

according to guideline

Guideline:

OECD Guideline 310 (Ready Biodegradability - CO2 in Sealed Vessels (Headspace Test)

Version / remarks:

(2006)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

- Source of activated sludge: Municipal sewage treatment plant, D-31137 Hildesheim, Germany, receiving predominantly municipal sewage
- Pretreatment: The activated sludge was washed twice with autoclaved tap water. After the second washing the settled sludge was resuspended in mineral salts medium and was maintained in an aerobic condition by aeration for 4 hours. Thereafter the sludge was homogenized with a blender. The supernatant was decanted and was maintained in an aerobic condition by aeration with CO2-free air for 2 days.
- Volume: 10 mL per litre of test solution (10^5 - 10^8 CFU/L test solution)

Duration of test (contact time):

28 d

Initial conc.:

14.5 mg/L

Based on:

TOC

Initial conc.:

20 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

inorg. C analysis

Details on study design:

TEST CONDITIONS
- Test temperature: 21-23°C, except for 18 hours, when it was 20°C (considered to have no impact on the study)
- Composition of mineral medium: in accordance with OECD TG310
- Test medium: mineral medium and inoculum in demineralised water
- pH: not measured
- Suspended solids concentration: not reported
- Agitation: yes, shaker, 150-200 rpm
- Low light conditions

TEST SYSTEM
- Test vessel: Headspace flask of 120 mL, sealed with a septum
- Volume of test medium: 80 mL
- Application of the test substance: as such (1.8 µL) by injection through the septum
- Number of test substance and reference control flasks (replicates): Day 0-21: 3; Day 28: 5
- Measuring equipment: Carbon analyser, Multi N/C 3000, Analytik Jena

SAMPLING
- Sampling frequency (toxicity control): Day 0, 7, 14, 21 and 28
- Sampling frequency (all other vessels): Day 0, 2, 5, 7, 12, 14, 21 and 28
- Method: Sodium hydroxide solution (0.74 mL of 7 M to 80 mL test medium) was injected to each vessel sampled. The vessels were shaken on an overhead shaker (100 rpm) for 1 hour. Suitable volumes of the liquid phase were analysed.
- Storage: If necessary, samples were stored at 6 ± 2°C until analysis

CONTROL AND BLANK SYSTEM
- Inoculum blank (replicates): Day 0-21: 3; Day 28: 5
- Abiotic sterile control: not applicable
- Toxicity control (replicates): Day 0-21: 3; Day 28: 5

Reference substance:

benzoic acid, sodium salt

Remarks:

(17.5 mg TOC/L)

Key result

Parameter:

% degradation (inorg. C analysis)

Value:

79

Sampling time:

28 d

Details on results:

- As a degree of biodegradation of ≥10% (20%) was reached at Day 5 and a degree of >60% (62%) at Day 12, the substance was found to be readily biodegradable
- The substance was found to not inhibit microbial activity. A degree of biodegradation of >60% (73%) was reached at Day 14 in the toxicity control.

Results with reference substance:

The positive control substance was biodegraded by at least 60% (90%) within 14 days.

The validity criteria of the standard 28-day test are fulfilled:

1. the mean percentage degradation of the reference substance was >60% by the 14th day of incubation (90%)

2. the mean amount of IC present in the blank controls at the end of the test was < 3 mg C/L (1.44 mg C/L)

Validity criteria fulfilled:

yes

Remarks:

Reference substance was biodegraded > 60% within 14 days

Interpretation of results:

readily biodegradable

Conclusions:

Profarnesal (CAS number 54082-68-7) showed 79% biodegradation in an OECD TG 310 test.

Executive summary:

The ready biodegradability of Profarnesal (CAS number 54082-68-7) was investigated in a study conducted in accordance with OECD TG 310 (Headspace Test) and GLP. The concentration tested was 20 mg/L test substance, with an inoculum concentration of 10 mL/L. The test substance biodegraded for 79% in 28 days and was not toxic to the inoculum. Profarnesal (CAS number 54082-68-7) was concluded to be readily biodegradable.

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 information is derived from read across

Justification for type of information:

Executive summary: The ready biodegradability of Geraldehyde is assessed by using read across from Profarnesal (CAS number 54082-68-7), which results in Geraldehyde being readily biodegradable. Full details are provided in the study record. Structural analogy: The chemical names of Geraldehyde and Profarnesal already present the analogy: 2,6,10-trimethylundeca-5,9-dienal and 5,9-dimethyldeca-4,8-dienal, respectively; both have a C10 or C11 backbone with two isolated double bonds and two or three methyl groups. Both substances have an aldehyde functional group at the end of the chain. Bioavailability: The similarity in bioavailability of both substances for bacteria can be assessed using the phys-chem properties of the source Profarnesal and target Geraldehyde. Profarnesal is expected to be slightly less water soluble compared to Geraldehyde (1 and 9 mg/l, respectively) and therefore biodegradation may be faster and higher for Geraldehyde. Uncertainty of the ready biodegradation prediction: There is limited uncertainty based on the reasoning above. In addition, the read across and the result is further supported by BIOWIN in EPISUITE, which predicts both substances to be readily biodegradable. Geraldehyde (the target) is expected to be readily biodegradable: BIOWIN 5 and 6 show probabilities of 0.80 and 0.87, respectively, while the cut off is > 0.5 for ready biodegradable. For Profarnesal these probability predictions are: 0.66 and 0.73, respectively.

Reason / purpose for cross-reference:

read-across source

Key result

Parameter:

% degradation (inorg. C analysis)

Value:

79

Sampling time:

28 d

Remarks on result:

other: Data for the read-across substance Profarnesal.

Interpretation of results:

readily biodegradable

Conclusions:

It can be concluded that the substance is readily biodegradable.

Description of key information

The result is read-across for Geraldehyde from Profarnesal (CAS number 54082 -68 -7).

Profarnesal is readily biodegradable.

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Additional information

The biodegradation is based on read across to Profarnesal. First the study with the analogue is described and thereafter the read across justification is presented.

The ready biodegradability of Profarnesal (CAS number 54082-68-7) was investigated in a study conducted in accordance with OECD TG 310 (Headspace Test) and GLP. The concentration tested was 20 mg/L test substance, with an inoculum concentration of 10 mL/L. The test substance biodegraded for 79% in 28 days and was not toxic to the inoculum. Profarnesal (CAS number 54082-68-7) was concluded to be readily biodegradable.

Geraldehyde and its ready biodegradability in water sediment using read across information from Profarnesal (CAS number 54082-68-7)

 

Introduction and hypothesis for the analogue approach

Geraldehyde is an alkane structure with two isolated double bonds and two methyl-branches. The substance consists of the E- and Z-isomer of the internal double bond (42:56%). For Geraldehyde data on biodegradation in a water – screening - system are lacking. 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 assessing the ready biodegradation of the substance in water - sediment the analogue approach is selected because for one closely related analogue a reliable ready biodegradability study is available.

Hypothesis:Geraldehydeis expected to have similar biodegradation percentage as Profarnesal or even higher, because Profarnesal may be slightly less bioavailable to bacteria due to its slightly lower water solubility and therefore the read across is considered a conservative.

Available experimental information: No data are available for Geraldehyde.There are data available for the analogue, Profarnesal, demonstrating that this substance is readily biodegradable in an OECD 310 test (Symrise, 2011b; GLP, OECD 310, K1). It was biodegraded by49, 65, 72 and 79% after 7, 14, 21 and 28 days, respectively.The test shows the substance to be readily biodegradable (79% in 28 days).

Target chemical and source chemical(s)

Chemical structures of the target chemical and the source chemical are shown in the data matrix. Also physico-chemical properties thought to be relevant for biodegradation are listed in there. 

 

Purity / Impurities

The purity, the constituents and impurities of the target chemical do indicate a similar biodegradation potential. The impurities are all below < 10%.

 

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.

 

Analogue selection:

In accordance with ECHA Guidance (2015, RAAF), Profarnesal was selected being the closest analogue for which biodegradation information was available.Profarnesal was selected based on structural similarity and the presence of useful data for read-across, out of all analogues identified in the OECD QSAR toolbox using Tanimoto similarity of 75% and analogues identified in the RIFM database

 

Structural analogy:

·        The chemical names of Geraldehyde and Profarnesal already present the analogy:2,6,10-trimethylundeca-5,9-dienal and 5,9-dimethyldeca-4,8-dienal, respectively; both have a C10 or C11 backbone with two isolated double bonds and two or three methyl groups. Both substances have an aldehyde functional group at the end of the chain.

Bioavailability:

·        The similarity in bioavailability of both substances for bacteria can be assessed using the phys-chem properties of the source Profarnesal and target Geraldehyde. Profarnesal is expected to be slightly less water soluble compared to Geraldehyde(1 and 9 mg/l, respectively)and therefore biodegradation may be faster and higher for Geraldehyde. 

 

Uncertainty of the ready biodegradation prediction:

·        There is limited uncertainty based on the reasoning above. In addition, the read across and the result isfurther supported by BIOWINin EPISUITE, which predicts both substances to be readily biodegradable. Geraldehyde (the target) is expected to be readily biodegradable: BIOWIN 5 and 6 show probabilities of 0.80 and 0.87, respectively, while the cut off is > 0.5 for ready biodegradable. For Profarnesal these probability predictions are: 0.66 and 0.73, respectively.In view of the presented reasoning above and in accordance with the ECHA guidance (RAAF, 2015) terminology, the read-across receives code 5 (acceptable with high confidence).

 

Data matrix

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

 

Conclusions on the ready biodegradability of Geraldehyde

When using read across, the result derived should be applicable for C&L and/or risk assessment and be presented with adequate and reliable documentation. The information from the source substance (Profarnesal) is reliable. In view of the analogy of the two substances, these data can be used for the read-across for Geraldehyde.

Final conclusion on fate: Profarnesal is readily biodegradable, and therefore also Geraldehyde is readily biodegradable.

 

Data matrix of Geraldehyde using read across from Profarnesal.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   

Common names	Geraldehyde	Profarnesal
Chemical structures
Empirical formula	C12H20O	C14H24O
Physico-chemical data
Molecular weight	180.91	208.35
Physical state	Liquid	Liquid
Vapour pressure Pa	2.96 at 25°C (EpiSuite); 2.22 at 24°C (measured)	0.83 at 25°C (EpiSuite)
Water solubility mg/l	9 (from Log Kow) (EpiSuite) 52.2 mg/l at 24°C (measured)	1 (from Log Kow)
Log Kow	4.4 (EpiSuite); 4.4 (measured)	5.3(EpiSuite)
Biodegradation %	read across from Profarnesal	79% after 28 days
EPISUITE prediction	BIOWIN5 = 0.80, BIOWIN6 = 0.87	BIOWIN5 = 0.66, BIOWIN6 = 0.73