Phenethyl valerate

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 prediction was done by using OECD QSAR tool box v3.4

GLP compliance:

not specified

Specific details on test material used for the study:

- Name of the test material: 2-phenylethyl pentanoate
- IUPAC name: 2-phenylethyl pentanoate
- Molecular formula: C13H18O2
- Molecular weight: 206.283 g/mol
- Smiles notation: O=C(OCCc1ccccc1)CCCC
- InChl: 1S/C13H18O2/c1-2-3-9-13(14)15-11-10-12-7-5-4-6-8-12/h4-8H,2-3,9-11H2,1H3
- Substance type: Organic

Oxygen conditions:

aerobic

Inoculum or test system:

other: MIcroorganisms

Duration of test (contact time):

28 d

Parameter followed for biodegradation estimation:

other: BOD

Key result

Parameter:

other: % biodegradation (BOD)

Value:

93.167

Sampling time:

28 d

Remarks on result:

other: other details not available

Details on results:

The target chemical 2-phenylethyl pentanoate undergoes 93.166 % degradation by considering BOD as parameter in 28 days.

The prediction was based on dataset comprised from the following descriptors: BOD
Estimation method: Takes average value from the 6 nearest neighbours
Domain  logical expression:Result: In Domain

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

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 Michael addition AND Michael addition >> P450 Mediated Activation to Quinones and Quinone-type Chemicals AND Michael addition >> P450 Mediated Activation to Quinones and Quinone-type Chemicals >> Arenes by DNA binding by OECD

Domain logical expression index: "c"

Referential boundary: The target chemical should be classified as Esters by Acute aquatic toxicity MOA by OASIS

Domain logical expression index: "d"

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

Domain logical expression index: "e"

Referential boundary: The target chemical should be classified as No alert found by DNA binding by OASIS v.1.4

Domain logical expression index: "f"

Referential boundary: The target chemical should be classified as AN2 OR AN2 >> Michael-type addition on alpha, beta-unsaturated carbonyl compounds OR AN2 >> Michael-type addition on alpha, beta-unsaturated carbonyl compounds >> Four- and Five-Membered Lactones OR AN2 >> Schiff base formation OR AN2 >> Schiff base formation >> Polarized Haloalkene Derivatives OR AN2 >> Schiff base formation by aldehyde formed after metabolic activation OR AN2 >> Schiff base formation by aldehyde formed after metabolic activation >> Geminal Polyhaloalkane Derivatives OR AN2 >> Shiff base formation after aldehyde release OR AN2 >> Shiff base formation after aldehyde release >> Specific Acetate Esters OR AN2 >> Shiff base formation for aldehydes OR AN2 >> Shiff base formation for aldehydes >> Haloalkane Derivatives with Labile Halogen OR AN2 >> Thioacylation via nucleophilic addition after cysteine-mediated thioketene formation OR AN2 >> Thioacylation via nucleophilic addition after cysteine-mediated thioketene formation >> Haloalkenes with Electron-Withdrawing Groups OR AN2 >> Thioacylation via nucleophilic addition after cysteine-mediated thioketene formation >> Polarized Haloalkene Derivatives OR Non-covalent interaction OR Non-covalent interaction >> DNA intercalation OR Non-covalent interaction >> DNA intercalation >> Coumarins OR Non-covalent interaction >> DNA intercalation >> DNA Intercalators with Carboxamide and Aminoalkylamine Side Chain OR Radical OR Radical >> Generation of ROS by glutathione depletion (indirect) OR Radical >> Generation of ROS by glutathione depletion (indirect) >> Haloalkanes Containing Heteroatom OR Radical >> Radical mechanism by ROS formation (indirect) or direct radical attack on DNA OR Radical >> Radical mechanism by ROS formation (indirect) or direct radical attack on DNA >> Organic Peroxy Compounds OR Radical >> Radical mechanism via ROS formation (indirect) OR Radical >> Radical mechanism via ROS formation (indirect) >> Coumarins OR Radical >> Radical mechanism via ROS formation (indirect) >> Geminal Polyhaloalkane Derivatives OR Radical >> Radical mechanism via ROS formation (indirect) >> Nitro Azoarenes OR Radical >> Radical mechanism via ROS formation (indirect) >> Thiols OR SN1 OR SN1 >> Nucleophilic attack after carbenium ion formation OR SN1 >> Nucleophilic attack after carbenium ion formation >> Specific Acetate Esters OR SN1 >> Nucleophilic attack after reduction and nitrenium ion formation OR SN1 >> Nucleophilic attack after reduction and nitrenium ion formation >> Nitro Azoarenes OR SN2 OR SN2 >> Acylation OR SN2 >> Acylation >> Specific Acetate Esters OR SN2 >> Acylation involving a leaving group  OR SN2 >> Acylation involving a leaving group  >> Haloalkane Derivatives with Labile Halogen OR SN2 >> Acylation involving a leaving group after metabolic activation OR SN2 >> Acylation involving a leaving group after metabolic activation >> Geminal Polyhaloalkane Derivatives OR SN2 >> Alkylation OR SN2 >> Alkylation >> Alkylphosphates, Alkylthiophosphates and Alkylphosphonates OR SN2 >> Alkylation, direct acting epoxides and related OR SN2 >> Alkylation, direct acting epoxides and related >> Epoxides and Aziridines OR SN2 >> Alkylation, direct acting epoxides and related after P450-mediated metabolic activation OR SN2 >> Alkylation, direct acting epoxides and related after P450-mediated metabolic activation >> Haloalkenes with Electron-Withdrawing Groups OR SN2 >> Alkylation, direct acting epoxides and related after P450-mediated metabolic activation >> Polarized Haloalkene Derivatives OR SN2 >> Alkylation, nucleophilic substitution at sp3-carbon atom OR SN2 >> Alkylation, nucleophilic substitution at sp3-carbon atom >> Haloalkane Derivatives with Labile Halogen OR SN2 >> Alkylation, nucleophilic substitution at sp3-carbon atom >> Haloalkanes Containing Heteroatom OR SN2 >> Alkylation, nucleophilic substitution at sp3-carbon atom >> Sulfonates and Sulfates OR SN2 >> Alkylation, ring opening SN2 reaction OR SN2 >> Alkylation, ring opening SN2 reaction >> Four- and Five-Membered Lactones OR SN2 >> Alkylation, ring opening SN2 reaction >> Sultones OR SN2 >> Direct acting epoxides formed after metabolic activation OR SN2 >> Direct acting epoxides formed after metabolic activation >> Coumarins OR SN2 >> DNA alkylation OR SN2 >> DNA alkylation >> Vicinal Dihaloalkanes OR SN2 >> Internal SN2 reaction with aziridinium and/or cyclic sulfonium ion formation (enzymatic) OR SN2 >> Internal SN2 reaction with aziridinium and/or cyclic sulfonium ion formation (enzymatic) >> Vicinal Dihaloalkanes OR SN2 >> Nucleophilic substitution at sp3 Carbon atom OR SN2 >> Nucleophilic substitution at sp3 Carbon atom >> Haloalkanes Containing Heteroatom OR SN2 >> Nucleophilic substitution at sp3 Carbon atom >> Specific Acetate Esters OR SN2 >> Nucleophilic substitution at sp3 carbon atom after thiol (glutathione) conjugation OR SN2 >> Nucleophilic substitution at sp3 carbon atom after thiol (glutathione) conjugation >> Geminal Polyhaloalkane Derivatives OR SN2 >> SN2 at sp3 and activated sp2 carbon atom OR SN2 >> SN2 at sp3 and activated sp2 carbon atom >> Polarized Haloalkene Derivatives by DNA binding by OASIS v.1.4

Domain logical expression index: "g"

Referential boundary: The target chemical should be classified as Not calculated by Biodeg BioHC half-life (Biowin) ONLY

Domain logical expression index: "h"

Referential boundary: The target chemical should be classified as Biodegrades Fast by Biodeg probability (Biowin 1) ONLY

Domain logical expression index: "i"

Referential boundary: The target chemical should be classified as Biodegrades Fast by Biodeg probability (Biowin 5) ONLY

Domain logical expression index: "j"

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

Domain logical expression index: "k"

Referential boundary: The target chemical should be classified as days - weeks by Biodeg ultimate (Biowin 3) ONLY

Domain logical expression index: "l"

Referential boundary: The target chemical should be classified as Not possible to classify according to these rules by DPRA Cysteine peptide depletion

Domain logical expression index: "m"

Referential boundary: The target chemical should be classified as High reactive OR High reactive >> alpha,beta-carbonyl compounds with polarized multiple bonds OR Moderate reactive OR Moderate reactive >> Mono-methacrylic acid esters by DPRA Cysteine peptide depletion

Domain logical expression index: "n"

Referential boundary: The target chemical should be classified as Non binder, without OH or NH2 group by Estrogen Receptor Binding

Domain logical expression index: "o"

Referential boundary: The target chemical should be classified as Non binder, impaired OH or NH2 group OR Non binder, MW>500 OR Non binder, non cyclic structure by Estrogen Receptor Binding

Domain logical expression index: "p"

Referential boundary: The target chemical should be classified as Bioavailable by Lipinski Rule Oasis ONLY

Domain logical expression index: "q"

Referential boundary: The target chemical should be classified as Non-Metals by Groups of elements

Domain logical expression index: "r"

Referential boundary: The target chemical should be classified as Alkali Earth by Groups of elements

Domain logical expression index: "s"

Similarity boundary:Target: CCCCC(=O)OCCc1ccccc1
Threshold=60%,
Dice(Atom centered fragments)
Atom type; Count H attached; Hybridization

Domain logical expression index: "t"

Similarity boundary:Target: CCCCC(=O)OCCc1ccccc1
Threshold=80%,
Dice(Atom centered fragments)
Atom type; Count H attached; Hybridization

Domain logical expression index: "u"

Parametric boundary:The target chemical should have a value of Molecular weight which is >= 134 Da

Domain logical expression index: "v"

Parametric boundary:The target chemical should have a value of Molecular weight which is <= 254 Da

Validity criteria fulfilled:

not specified

Interpretation of results:

readily biodegradable

Conclusions:

The target chemical 2-phenylethyl pentanoate undergoes 93.166 % degradation by considering BOD as parameter and Microorganisms as inoculum in 28 days.

Executive summary:

Biodegradability of test chemical 2-phenylethyl pentanoate was predicted by using OECD QSAR tool box v3.4 with log Kow as primary descriptor. The target chemical 2-phenylethyl pentanoate undergoes 93.166 % degradation by considering BOD as parameter and Microorganisms as inoculum in 28 days. Based on percent degradation value it is concluded that this test chemical is readily biodegradable.

Description of key information

Biodegradability of test chemical 2-phenylethyl pentanoate was predicted by using OECD QSAR tool box v3.4 with log Kow as primary descriptor. The target chemical 2-phenylethyl pentanoate undergoes 93.166 % degradation by considering BOD as parameter and Microorganisms as inoculum in 28 days. Based on percent degradation value it is concluded that this test chemical is readily biodegradable.

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Additional information

Predicted data for the target compound2-phenylethyl pentanoateand supporting weight of evidence studies for its read across substance were reviewed for the biodegradation end point which are summarized as below:

Biodegradability of test chemical 2-phenylethyl pentanoate was predicted by using OECD QSAR tool box v3.4 with log Kow as primary descriptor. The target chemical 2-phenylethyl pentanoate undergoes 93.166 % degradation by considering BOD as parameter and Microorganisms as inoculum in 28 days. Based on percent degradation value it is concluded that this test chemical is readily biodegradable.

 

Another prediction was done by using Estimation Programs Interface Suite (EPI suite, 2017)to determine the biodegradation potential of the test compound 2-phenylethyl pentanoate (CAS no. 7460 -74 -4) in the presence of mixed populations of environmental microorganisms. 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 2-phenylethyl pentanoate is expected to be readily biodegradable.

 

In a supporting weight of evidence study for read across chemical benzyl acetate from Chemophere journal the biodegradation study was conducted for 28 days(4 weeks) for evaluating the percentage biodegradability of the test substance using the OECD Guideline 301 B (Ready Biodegradability: CO2 Evolution Test) and Other guideline: New Biodegradability Test developed. The Sturm method was used in conjunction to validate the results of the new method.

The test was performed under aerobic conditions using activated sludge as an inoculum with conc. of 30 mg/l and initial test substance conc. is 10 mg/l (ranges from 2 – 10 mg/l). The read across substance in a dilute mineral salts solution is incubated in sealed vessels with appropriate micro-organisms for a period of up to 28 days. Controls containing the 0.5 to 10% inoculum concentration, without read across chemical are also prepared.

A vessel is removed from the shaker as required, a sample of the headspace gas withdrawn using a gas syringe and the concentration of carbon dioxide determined. The seal is then broken and the concentration of dissolved inorganic carbon (DIC) in the solution is measured immediately, Similar determinations are made for a control vessel which does not contain the read across substance. The difference in the total inorganic carbon found in the test and control vessels allows the quantity of carbon dioxide produced from the test compound to be ascertained.

The determination of carbon dioxide in both gaseous and aqueous samples was performed using a modified Ionics 555 TC-T°C Analyser. Carbon dioxide is released from aqueous samples of carbonate/bicarbonate by direct injection using a 0-200 µl Hamilton constant rate syringe onto an inert support loaded with phosphoric acid. The temperature in the reaction chamber is controlled at 150°C and pure nitrogen is used as the carrier gas. The detection system is a high sensitivity non-dispersive infra-red analyser. Gaseous samples are injected using a good quality gastight syringe.

A preliminary study was conducted using 2 mg/L of test substance conc. The percentage biodegradation of read across substance was determined to be 100.9% with standard deviation of 2.5 and 95% confidence interval of 96.9 – 104.9. Thus, the read across substance benzyl acetate was determined to be readily biodegradable.

 

 

In another weight of evidence study for read across chemical 2 -phenylethyl propanoate from Pest management Science journal ( 2008) the Biodegradation experiment was conducted for 30 days for evaluating the percentage biodegradability of read across substance 2 -phenylethyl propanoate. Pond water was used as a test inoculum collected from the Iowa State University Horticulture Farm pond (Ames, IA, USA). Initial test substance conc. used for the study was 10μg/g. The pH of the water was 7.3, the alkalinity was 91 mg/ml, and the total hardness was 182 mg/ml. Pond water (100 ml) was kept in French square bottles and spiked with 3H-PEP in 300 μl of acetone carrier solvent to result in a concentration of 10 μg/ml. The samples were incubated in dark and in light separately, and were maintained at a constant temperature of 25 ± 2°C throughout the study in the environmental chamber. Aluminum foil wrapping was used to prevent “dark” incubations from having exposure to light. Samples were taken at days 0, 0.25, 0.5, 1, 3, 7, 14, 21 and 30 post-treatment. Quantitative analysis of PEP was performed using a Hewlett-Packard (Palo Alto, CA, USA) series 1100 HPLC system with a quaternary pump, an autosampler, a thermostatted column compartment, and a Spectroflow 757 absorbance detector (ABI Analytical, Kratos Division, Ramsey, NJ, USA). Data were collected and analyzed using HP Chemstation system software (REV. A.04.01). An Alltech Adsorbosphere® (Deerfield, IL, USA) C18 column (4.6×250 mm, 5-μm particle size) was used. Detection was conducted at 270 nm with a flow rate of 1.0 ml/min at room temperature. The mobile phase was methanol/distilled water (70:30, v/v).Dissipation rates of PEP were calculated using first-order open models. A student’s-test was used to compare dissipation rates of PEP in light and in dark from the water dissipation studies. Dissipation of PEP in water was very rapid with a DT 50 of 5 days. Volatility loss was negligible in one month with mass balance from 96% to 100%. The primary degradation product was 2-phenylethanol, which was produced from ester hydrolysis of phenethyl propionate; another degradation product was 2-(4-hydroxyphenyl) ethanol, which was probably a biotransformation product of 2-phenylethanol in microbes. The percentage degradation of read across substance 2-phenylethyl propanoate was determined to be 50% in 5 days. Thus, based on percentage degradation, 2-phenylethyl propanoate is considered to be readily biodegradable in nature.

 

On the basis of results of above mentioned studies for target chemical 2-phenylethyl pentanoate (CAS No. 7460-74-4) (from OECD QSAR tool box v3.4 and EPI suite) and supporting weight of evidence study (from chemosphere and Pest management Science journal). It is concluded that the test chemical 2-phenylethyl pentanoat ecan be expected to be readily biodegradable.