Geranyl propionate

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Endpoint:

biodegradation in water: screening tests

Type of information:

(Q)SAR

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

results derived from a valid (Q)SAR model and falling into its applicability domain, with limited documentation / justification

Justification for type of information:

The supporting QMRF report has been attached

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 C (Ready Biodegradability: Modified MITI Test (I))

Principles of method if other than guideline:

The data is predicted using the OECD QSAR toolbox version 3.4 with logKow as the primary descriptor.

GLP compliance:

not specified

Specific details on test material used for the study:

- Name of test material (IUPAC name): (2E)-3,7-dimethylocta-2,6-dien-1-yl propanoate
- Common name: Geranyl propionate
- Molecular formula: C13H22O2
- Molecular weight: 210. 3148 g/mol
- Smiles notation: CCC(=O)OC\C=C(/C)\CCC=C(C)C
- InChl: 1S/C13H22O2/c1-5-13(14)15-10-9-12(4)8-6-7-11(2)3/h7,9H,5-6,8,10H2,1-4H3/b12-9+
- Substance type: Organic
- Physical state: Liquid

Oxygen conditions:

aerobic

Inoculum or test system:

other: Microorganisms

Duration of test (contact time):

28 d

Based on:

not specified

Parameter followed for biodegradation estimation:

other: BOD

Key result

Parameter:

other: BOD

Value:

90

Sampling time:

28 d

Remarks on result:

other: Other details not known

Details on results:

Test substance undergoes 90% degradation by BOD in 28 days.

The prediction was based on dataset comprised from the following descriptors: BOD
Estimation method: Takes average value from the 5 nearest neighbours
Domain  logical expression:Result: In Domain

(((((((((((("a" or "b" or "c" or "d" )  and "e" )  and ("f" and ( not "g") )  )  and "h" )  and "i" )  and "j" )  and "k" )  and ("l" and ( not "m") )  )  and "n" )  and "o" )  and "p" )  and ("q" and "r" )  )

Domain logical expression index: "a"

Referential boundary: The target chemical should be classified as Esters (Acute toxicity) by US-EPA New Chemical Categories

Domain logical expression index: "b"

Referential boundary: The target chemical should be classified as SN2 AND SN2 >> SN2 Reaction at a sp3 carbon atom AND SN2 >> SN2 Reaction at a sp3 carbon atom >> Activated alkyl esters and thioesters  by Protein binding by OASIS v1.4

Domain logical expression index: "c"

Referential boundary: The target chemical should be classified as SN2 AND SN2 >> SN2 reaction at sp3 carbon atom AND SN2 >> SN2 reaction at sp3 carbon atom >> Allyl acetates and related chemicals by Protein binding by OECD

Domain logical expression index: "d"

Referential boundary: The target chemical should be classified as Esters AND Vinyl/Allyl Esters by Aquatic toxicity classification by ECOSAR

Domain logical expression index: "e"

Referential boundary: The target chemical should be classified as Biodegrades Fast by Biodeg probability (Biowin 6) ONLY

Domain logical expression index: "f"

Referential boundary: The target chemical should be classified as No alert found by DNA binding by OECD

Domain logical expression index: "g"

Referential boundary: The target chemical should be classified as Michael addition OR Michael addition >> P450 Mediated Activation to Quinones and Quinone-type Chemicals OR Michael addition >> P450 Mediated Activation to Quinones and Quinone-type Chemicals >> Arenes OR Michael addition >> Polarised Alkenes-Michael addition OR Michael addition >> Polarised Alkenes-Michael addition >> Alpha, beta- unsaturated esters OR SN1 OR SN1 >> Iminium Ion Formation OR SN1 >> Iminium Ion Formation >> Aliphatic tertiary amines OR SN2 OR SN2 >> Direct Acting Epoxides and related OR SN2 >> Direct Acting Epoxides and related >> Epoxides by DNA binding by OECD

Domain logical expression index: "h"

Referential boundary: The target chemical should be classified as > 100 days by Hydrolysis half-life (Kb, pH 7)(Hydrowin) ONLY

Domain logical expression index: "i"

Referential boundary: The target chemical should be classified as No superfragment by Superfragments ONLY

Domain logical expression index: "j"

Referential boundary: The target chemical should be classified as Low (Class I) by Toxic hazard classification by Cramer (extension) ONLY

Domain logical expression index: "k"

Referential boundary: The target chemical should be classified as Class 3 (unspecific reactivity) by Acute aquatic toxicity classification by Verhaar (Modified) ONLY

Domain logical expression index: "l"

Referential boundary: The target chemical should be classified as Esters AND Vinyl/Allyl Esters by Aquatic toxicity classification by ECOSAR

Domain logical expression index: "m"

Referential boundary: The target chemical should be classified as Acid moiety OR Surfactants-Nonionic by Aquatic toxicity classification by ECOSAR

Domain logical expression index: "n"

Similarity boundary:Target: CCC(=O)OCC=C(C)CCC=C(C)C
Threshold=10%,
Dice(Atom centered fragments)
Atom type; Count H attached; Hybridization

Domain logical expression index: "o"

Similarity boundary:Target: CCC(=O)OCC=C(C)CCC=C(C)C
Threshold=30%,
Dice(Atom centered fragments)
Atom type; Count H attached; Hybridization

Domain logical expression index: "p"

Similarity boundary:Target: CCC(=O)OCC=C(C)CCC=C(C)C
Threshold=40%,
Dice(Atom centered fragments)
Atom type; Count H attached; Hybridization

Domain logical expression index: "q"

Parametric boundary:The target chemical should have a value of Molecular weight which is >= 156 Da

Domain logical expression index: "r"

Parametric boundary:The target chemical should have a value of Molecular weight which is <= 278 Da

Validity criteria fulfilled:

not specified

Interpretation of results:

readily biodegradable

Conclusions:

The test chemical (2E)-3,7-dimethylocta-2,6-dien-1-yl propanoate was estimated to be readily biodegradable in water.

Executive summary:

Biodegradability of (2E)-3,7-dimethylocta-2,6-dien-1-yl propanoate (CAS no. 105 -90 -8) is predicted using QSAR toolbox version 3.4 with logKow as the primary descriptor. Test substance undergoes 90% degradation by BOD in 28 days. Thus, based on percentage degradation, the test chemical (2E)-3,7-dimethylocta-2,6-dien-1-yl propanoate was estimated to be readily biodegradable in water.

Description of key information

Biodegradability of (2E)-3,7-dimethylocta-2,6-dien-1-yl propanoate (CAS no. 105 -90 -8) is predicted using QSAR toolbox version 3.4 (2017) with logKow as the primary descriptor. Test substance undergoes 90% degradation by BOD in 28 days. Thus, based on percentage degradation, the test chemical (2E)-3,7-dimethylocta-2,6-dien-1-yl propanoate was estimated to be readily biodegradable in water.

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Additional information

Various predicted data for the target compound (2E)-3,7-dimethylocta-2,6-dien-1-yl propanoate (CAS No. 105-90-8) and supporting weight of evidence studies for its closest read across substance with logKow as the primary descriptor were reviewed for the biodegradation end point which are summarized as below:

 

In a prediction done by SSS (2017) using OECD QSAR toolbox version 3.4 with logKow as the primary descriptor, percentage biodegradability of test chemical(2E)-3,7-dimethylocta-2,6-dien-1-yl propanoate(CAS No. 105-90-8) was estimated.Test substance undergoes 90% degradation by BOD in 28 days. Thus, based on percentage degradation, the test chemical (2E)-3,7-dimethylocta-2,6-dien-1-yl propanoate was estimated to be readily biodegradable in water.

 

In another prediction using the Estimation Programs Interface Suite (EPI suite, 2017), the biodegradation potential of the test compound(2E)-3,7-dimethylocta-2,6-dien-1-yl propanoate(CAS No. 105-90-8) in the presence of mixed populations of environmental microorganisms was estimated.The biodegradability of the substance was calculated using seven different models such as Linear Model, Non-Linear Model, Ultimate Biodegradation Timeframe, Primary Biodegradation Timeframe, MITI Linear Model, MITI Non-Linear Model and Anaerobic Model (called as Biowin 1-7, respectively) of the BIOWIN v4.10 software. The results indicate that chemical (2E)-3,7-dimethylocta-2,6-dien-1-yl propanoate is expected to be readily biodegradable.

 

In a supporting weight of evidence study from peer reviewed journal (N. Scholz et.al; 1997) for the read across chemical 1,2-Benzenedicarboxylic acid, dibutyl ester (CAS no. 84-74-2), biodegradation experiment was conducted for 28 days for evaluating the percentage biodegradability of read across substance 1,2-Benzenedicarboxylic acid, dibutyl ester. The study was performed according to OECD Guideline 301 B (Ready Biodegradability: CO2 Evolution Test) (Modified Sturm test).Sewage sludge was used as a test inoculum during the study. As biological inoculum a sludge sample from a nearby sewage treatment plant, treating household sewage only, was employed. After collecting the sludge from the plant, it was washed thoroughly with an artificial mineral medium as described in the guidelines. The sludge was thoroughly mixed with the final washing solution and an appropriate amount was then used as inoculum. Concentration of inoculum i.e, sludge used was 29 mg/l suspended solids, which corresponds to roughly60 x 104 cfu / ml (colony forming units)and initial test substance conc. used in the study was 15 mg/l, respectively. Special care has been taken to introduce the test substance into the Sturm test vessels. The phthalates (test chemical) have been dosed into precleaned Eppendorf vials at an amount corresponding to 15 mg organic carbon by direct weighing. One day before the start of the test, the vessels are filled with the mineral medium and the prewashed inoculum, sealed airtight and flushed with CO2 free air. The Eppendorf vials are placed within the Sturm test bottles by opening a small stop cock. The whole system is subsequently closed airtight again and flushed with CO2 free air.In the study, the test substance was incubated in a mineral medium and inoculated with a minor amount of sewage sludge. No further carbon source is offered to the organisms during the study. The system is sealed air tight and flushed with CO, free air. The amount of carbon dioxide generated during the 28 days exposure is then determined.CO2 evolution has been measured with a cabon analyzer TOC 500, by injection of 10-20μl of a sample of the carbon trap content. The evolved carbon dioxide was put into relation to the carbon content of the sample introduced, and the amount of degradation was calculated over the sampling time. The test stopped after 28 days. The total content of the Sturm test vessel is then acidified to drive out remaining CO2 traces from the vessel into the NaOH trap. CO2 evolution has been measured with a cabon analyzer TOC 500, by injection of 10-20μl of a sample of the carbon trap content. A second control without any organic carbon was set up to compensate for any CO2 release during sample introduction and the self aspiration of the inoculum. Quite a rapid onset of the CO2 evolution can be observed, and, starting with the 10 % value, the minimum biodegradation of test chemical1,2-Benzenedicarboxylic acid, dibutyl ester with percentage degradation of 60 % is easily accomplished within the next 10 subsequent days. Thus, the 10 day window criteria has been reached. The percentage degradation of substance 1,2-Benzenedicarboxylic acid, dibutyl ester was determined to be79 to 85% by CO2 evolution parameter in 28 days. Thus, based on percentage degradation,1,2-Benzenedicarboxylic acid, dibutyl ester is considered to be readily biodegradable in nature.

 

For the read across chemical 1,2-Benzenedicarboxylic acid, 1,2-diethyl ester (CAS no. 84-66-2), biodegradation study was conducted for 28 days for evaluating the percentage biodegradability of read across substance 1,2-Benzenedicarboxylic acid, 1,2-diethyl ester by using a settled domestic wastewater as microbial inoculum (Henry H. Tabak et. al; 1981). Settled domestic wastewater was used as a microbial inoculum. Conc. of test substance used for the study are 5 and 10 mg/l, respectively. Biochemical oxygen demand (BOD) dilution water containing 5mg of yeast extract per litre, was used as the synthetic medium. Stock solution of test substance was prepared in absolute ethanol. Stock solutions were prepared as 10% solutions. Erlenmeyer flasks was used as a test vessel. Test also involve the incorporation of both the medium-inoculum control to serve as blank control for determining base lines for both GC analysis and for DOC and TOC as well as the medium-substrate control series for determination of possible autooxidation, photolysis, and volatilization. Homogenous suspension of 1,2-Benzenedicarboxylic acid, 1,2-diethyl ester (Diethyl phthalate) in the synthetic medium were prepared by adding appropriate amounts of test compound to prechilled synthetic medium in a heavy-duty blender and blending the medium for 2 mins. The blended substrate containing media were then introduced into Erlenmeyer flasks and inoculated with prechilled yeast extract and settled domestic wastewater inoculum. The flasks containing the medium with the test compound and inoculum, as well as the medium-wastewater and medium-test compound control flasks, were incubated in a constant temperature room at 25°C in darkness. Flasks were shaken on a daily basis during the incubation period. The culture samples were extracted three times with 20 ml portions of methylene chloride at neutral pH, except for the control phenol culture samples which were acidified before extraction. The extraction, evaporation, and sparging procedure was that used for phenolic compounds. Duplicate samples at the beginning of each incubation period and triplicate samples at the end of the 7-day incubation for the original and each subculture were subjected to GC, TOC and DOC analysis. The percentage degradation of test substance1,2-Benzenedicarboxylic acid, 1,2-diethyl ester was determined to be 100% by GC, TOC or DOC analysis after 7 days. Based on the percentage degradation, the test chemical 1,2-Benzenedicarboxylic acid, 1,2-diethyl ester was considered to be readily biodegradable in nature.

 

Another biodegradation study from peer reviewed journal (RICHARD H. SUGATT et. al; 1984) was conducted according to CO2 evolution shake flask test for 28 days for evaluating the percentage biodegradability of the same read across substance 1,2-Benzenedicarboxylic acid, 1,2-diethyl ester (CAS no. 84-66-2).The study was performed under aerobic conditions at a temperature of22 ± 2°C and a pH7 ± 0.2, respectively. Initial test substance conc. used in the study was 20 mg/l, respectively. Mixture of soil and sewage microorganisms was used as a test inoculum for the study. The inoculum was prepared from soil, sewage microorganisms, and test chemical1,2-Benzenedicarboxylic acid, 1,2-diethyl ester (Diethyl phthalate)in a 2-week acclimation period before the test initiation. For test chemical, 1 liter of acclimation medium in a 2-liter Erlenmeyer flask was inoculated with a1,2-Benzenedicarboxylic acid, 1,2-diethyl ester concentration equivalent to 4 mg of carbon at the start of acclimation. The acclimation flasks were sealed and incubated in the dark on a Gyrotory shaker at 120 rpm and 22 ± 2°C. An additional test compound equivalent to 8 mg of carbon was added on day 7 and again on day 11 during the 14-day acclimation period. At the end of the acclimation period, the contents of all of the acclimation flasks in a set were pooled and filtered through glass wool to provide a common inoculum for the primary and ultimate biodegradation tests.

A measured weight (nominal 20 mg) of test compound (1,2-Benzenedicarboxylic acid, 1,2-diethyl esteror glucose) on a preweighed glass slide was added to the appropriate flasks. Then, 100 ml of the pooled acclimation inoculum was added to the seven flasks for each test chemical in a set and to the glucose and blank control flasks. The blank control flask received neither1,2-Benzenedicarboxylic acid, 1,2-diethyl esternor glucose. After the addition of the test compound, the pH was measured and was 7.0 + 0.2 without adjustment. The contents of two of the Erlenmeyer flasks for test chemical1,2-Benzenedicarboxylic acid, 1,2-diethyl ester were immediately extracted for specific chemical analysis at time zero to determine the percent recovery. The remaining flasks were sparged with 70% oxygen in nitrogen (CO2 free) for 5 min to remove CO2 and sealed, and 10 ml of 0.2 N Ba(OH)2 base was added to the central suspended reservoir of the CO2 evolution flasks by injection through the septum seal. The flasks were incubated in the dark on a Gyrotory shaker at 120 rpm and 22 ± 2°C.Differences in the CO2 evolution between control flasks containing no test chemical and flasks containing1,2-Benzenedicarboxylic acid, 1,2-diethyl ester were used to determine the extent and rate of ultimate biodegradation. At the beginning, middle, and end of the test, the entire contents of replicate flasks were extracted with hexane, and the concentrated extract was analyzed by gas chromatography with a flame ionization detector to determine the amount of 1,2-Benzenedicarboxylic acid, 1,2-diethyl ester remaining (primary biodegradation).The percentage degradation of test substance1,2-Benzenedicarboxylic acid, 1,2-diethyl ester was determined to be>99% and 95% by test material analysis and CO2 evolution parameter in 28 days. Thus, based on percentage degradation,1,2-Benzenedicarboxylic acid, 1,2-diethyl ester is considered to be readily biodegradable in nature.

 

In a supporting weight of evidence study from authoritative database (J-CHECK, 2017 and EnviChem, 2014) for the read across chemical 3-hydroxy-2,2,4-trimethylpentyl 2-methylpropanoate (CAS no. 77-68-9),biodegradation experiment was conducted for 28 days for evaluating the percentage biodegradability of read across substance 3-hydroxy-2,2,4-trimethylpentyl 2-methylpropanoate. The study was performed according to OECD Guideline 301 C (Ready Biodegradability: Modified MITI Test (I)). Concentration of inoculum i.e, sludge used was 30 mg/l and initial test substance conc. used in the study was 100 mg/l, respectively. The percentage degradation of read across substance 3-hydroxy-2,2,4-trimethylpentyl 2-methylpropanoatewas determined to be96, 94 and 100% by BOD, TOC removal and GC parameter in 28 days. Thus, based on percentage degradation, 3-hydroxy-2,2,4-trimethylpentyl 2-methylpropanoate is considered to be readily biodegradable in nature.

 

On the basis of above results for target chemical(2E)-3,7-dimethylocta-2,6-dien-1-yl propanoate(from OECD QSAR toolbox version 3.3 and EPI suite, 2017) and for its read across substance (from peer reviewed journals and authoritative database J-CHECK & EnviChem), it can be concluded that the test substance(2E)-3,7-dimethylocta-2,6-dien-1-yl propanoate can be expected to be readily biodegradable in nature.