Pentyl phenylacetate

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

calculation (if not (Q)SAR)

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

accepted calculation method

Justification for type of information:

Data is from computational model developed by USEPA.

Qualifier:

according to guideline

Guideline:

other: Modeling database

Principles of method if other than guideline:

The Biodegradation Probability Program (BIOWIN) estimates the probability for the rapid aerobic biodegradation of an organic chemical in the presence of mixed populations of environmental microorganisms .The model is part of the EpiSuite program of the US-EPA. Estimations are made with BIOWIN version 4.10. Estimates are based upon fragment constants that were developed using multiple linear and non-linear regression analyses. Experimental biodegradation data for the multiple linear and non-linear regressions were obtained from Syracuse Research Corporation's (SRC) data base of evaluated biodegradation data (Howard et. al., 1987). This version (v4.10) designates the models as follows (see also Boethling et al. 2003):
Biowin1 = linear probability model
Biowin2 = nonlinear probability model
Biowin3 = expert survey ultimate biodegradation model
Biowin4 = expert survey primary biodegradation model
Biowin5 = MITI linear model
Biowin6 = MITI nonlinear model
Biowin7 = anaerobic biodegradation model

GLP compliance:

not specified

Specific details on test material used for the study:

- Name of test material : Pentyl phenylacetate
- Molecular formula : C13H18O2
- Molecular weight : 206.283 g/mole
- Smiles notation : C(=O)(Cc1ccccc1)OCCCCC
- InChl: 1S/C13H18O2/c1-2-3-7-10-15-13(14)11-12-8-5-4-6-9-12/h4-6,8-9H,2-3,7,10-11H2,1H3
- Substance type: Organic
- Physical state: Colorless liquid

Oxygen conditions:

not specified

Inoculum or test system:

other: mixed populations of environmental microorganisms

Duration of test (contact time):

3.129 wk

Details on study design:

Using the computer tool BIOWIN v4.10 by US-EPA (EPIWIN) the aerobic as well as the anaerobic biodegradability of the test material can be estimated. The follwoing seven different models are used by the tool: Linear Model, Non-Linear Model, Ultimate Biodegradation Timeframe, Primary Biodegradation Timeframe, MITI LInear Model, MITI Non-Linear Model and Anaerobic Model (calles Biowin 1-7, respectively). Due to this results the overall prediction of readily biodegradability is done for the desired chemical.

Biowin 1 and 2, are intended to convey a general indication of biodegradability under aerobic conditions, and not for any particular medium.
Biowin 1 (Linear model)
The fast biodegradation probability for any compound is calculated by summing, for all the fragments present in that compound, the fragment coefficient multiplied by the number of instances of the fragment in the compound (for MW, the value of that parameter is multiplied by its coefficient), and then adding this summation to the equation constant which is 0.7475. The summed values for each fragment coefficient multiplied by the number of instances appear in the "VALUE" column of the linear results screen.

Biowin 2 (Non-linear model)
Calculation of the fast biodegradation probability for any compound begins by summing, for all the fragments present in that compound, the fragment coefficient multiplied by the number of instances of the fragment in the compound (for MW, the value of that parameter is multiplied by its coefficient), then adding this summation to the equation constant which is 3.0087. The summed values for each fragment coefficient multiplied by the number of instances appear in the "VALUE" column of the non-linear results screen. The non-linear fast biodegradation probability is then calculated from the logistic equation as follows, where total = 3.0087 + the summation as described above:

Biowin 3 and 4 yield estimates for the time required to achieve complete ultimate and primary biodegradation in a typical or "evaluative" aquatic environment.

Biowin 5 and 6 are predictive models for assessing a compound’s biodegradability in the Japanese MITI (Ministry of International Trade and Industry) ready biodegradation test; i.e. OECD 301C. These models use an approach similar to that used to develop Biowin1 and 2. This protocol for determining ready biodegradability is among six officially approved as ready biodegradability test guidelines of the OECD (Organization for Economic Cooperation and Development). A total dataset of 884 chemicals was compiled to derive the fragment probability values that are applied in this MITI Biodegradability method. The dataset consists of 385 chemical that were critically evaluated as "readily degradable" and 499 chemicals that were critically evaluated as "not readily biodegradable".

Biowin 7, the anaerobic biodegradation model, is the most recent. As for the other Biowin models, multiple (linear) regression against molecular fragments was used to develop the model, which predicts probability of rapid degradation in the "serum bottle" anaerobic biodegradation screening test. This endpoint is assumed to be predictive of degradation in a typical anaerobic digester. Biowin7 estimates the probability of fast biodegradation under methanogenic anaerobic conditions; specifically, under the conditions of the "serum bottle" anaerobic biodegradation screening test (Meylan et al. 2007). A total of 169 compounds with serum bottle test data were identified for use in model development.

Out of seven different Biowin models, Biowin model 3 and 4 will help in estimating biodgeradability of the test chemical which was described as below-

Ultimate Biodegradation Timeframe and Primary Biodegradation Timeframe (Biowin 3 and 4)
These two models estimate the time required for "complete" ultimate and primary biodegradation.  Primary biodegradation is the transformation of a parent compound to an initial metabolite.  Ultimate biodegradation is the transformation of a parent compound to carbon dioxide and water, mineral oxides of any other elements present in the test compound, and new cell material. Then the rating was given to each model, which indicates the time required to achieve ultimate and primary biodegradation in a typical or "evaluative" aquatic environment. The ratings for each compound were averaged to obtain a single value for modeling.  The ultimate or primary rating of a compound is calculated by summing, for all the fragments present in that compound.

Parameter:

other: Half-life

Value:

50

Sampling time:

3.129 wk

Remarks on result:

other: readily biodegradable as estimated by BIOWIN model

Details on results:

Biowin1 (Linear Model Prediction) : 1.1147 (Biodegrades Fast)
Biowin2 (Non-Linear Model Prediction): 0.9998 (Biodegrades Fast)
Biowin3 (Ultimate Biodegradation Timeframe): 3.1290 (Weeks)
Biowin4 (Primary Biodegradation Timeframe): 3.9845 (Days)
Biowin5 (MITI Linear Model Prediction) :0.6256 (Biodegrades Fast)
Biowin6 (MITI Non-Linear Model Prediction): 0.7738 (Biodegrades Fast)
Biowin7 (Anaerobic Model Prediction): 0.3338 (Does Not Biodegrades Fast)
Ready Biodegradability Prediction: YES

BIOWIN (v4.10) Program Results:

==============================

SMILES : O=C(OCCCCC)Cc(cccc1)c1

CHEM : Benzeneacetic acid, pentyl ester

MOL FOR: C13 H18 O2

MOL WT : 206.29

--------------------------- BIOWIN v4.10 Results ----------------------------

Biowin1 (Linear Model Prediction) : Biodegrades Fast

Biowin2 (Non-Linear Model Prediction): Biodegrades Fast

Biowin3 (Ultimate Biodegradation Timeframe): Weeks

Biowin4 (Primary Biodegradation Timeframe): Days

Biowin5 (MITI Linear Model Prediction) : Biodegrades Fast

Biowin6 (MITI Non-Linear Model Prediction): Biodegrades Fast

Biowin7 (Anaerobic Model Prediction): Does Not Biodegrade Fast

Ready Biodegradability Prediction: YES

------+-----+--------------------------------------------+---------+---------

TYPE | NUM | Biowin1 FRAGMENT DESCRIPTION | COEFF | VALUE

------+-----+--------------------------------------------+---------+---------

Frag | 1 | Linear C4 terminal chain [CCC-CH3] | 0.1084 | 0.1084

Frag | 1 | Ester [-C(=O)-O-C] | 0.1742 | 0.1742

Frag | 1 | Alkyl substituent on aromatic ring | 0.0547 | 0.0547

Frag | 1 | Unsubstituted phenyl group (C6H5-) | 0.1281 | 0.1281

5

MolWt| * | Molecular Weight Parameter | | -0.0982

Const| * | Equation Constant | | 0.7475

============+============================================+=========+=========

RESULT | Biowin1 (Linear Biodeg Probability) | | 1.1147

============+============================================+=========+=========

------+-----+--------------------------------------------+---------+---------

TYPE | NUM | Biowin2 FRAGMENT DESCRIPTION | COEFF | VALUE

------+-----+--------------------------------------------+---------+---------

Frag | 1 | Linear C4 terminal chain [CCC-CH3] | 1.8437 | 1.8437

Frag | 1 | Ester [-C(=O)-O-C] | 4.0795 | 4.0795

Frag | 1 | Alkyl substituent on aromatic ring | 0.5771 | 0.5771

Frag | 1 | Unsubstituted phenyl group (C6H5-) | 1.7991 | 1.7991

MolWt| * | Molecular Weight Parameter | | -2.9293

============+============================================+=========+=========

RESULT | Biowin2 (Non-Linear Biodeg Probability) | | 0.9998

============+============================================+=========+=========

A Probability Greater Than or Equal to 0.5 indicates --> Biodegrades Fast

A Probability Less Than 0.5 indicates --> Does NOT Biodegrade Fast

------+-----+--------------------------------------------+---------+---------

TYPE | NUM | Biowin3 FRAGMENT DESCRIPTION | COEFF | VALUE

------+-----+--------------------------------------------+---------+---------

Frag | 1 | Linear C4 terminal chain [CCC-CH3] | 0.2983 | 0.2983

Frag | 1 | Ester [-C(=O)-O-C] | 0.1402 | 0.1402

Frag | 1 | Alkyl substituent on aromatic ring | -0.0749 | -0.0749

Frag | 1 | Unsubstituted phenyl group (C6H5-) | 0.0220 | 0.0220

MolWt| * | Molecular Weight Parameter | | -0.4559

Const| * | Equation Constant | | 3.1992

============+============================================+=========+=========

RESULT | Biowin3 (Survey Model - Ultimate Biodeg) | | 3.1290

============+============================================+=========+=========

------+-----+--------------------------------------------+---------+---------

TYPE | NUM | Biowin4 FRAGMENT DESCRIPTION | COEFF | VALUE

------+-----+--------------------------------------------+---------+---------

Frag | 1 | Linear C4 terminal chain [CCC-CH3] | 0.2691 | 0.2691

Frag | 1 | Ester [-C(=O)-O-C] | 0.2290 | 0.2290

Frag | 1 | Alkyl substituent on aromatic ring | -0.0685 | -0.0685

Frag | 1 | Unsubstituted phenyl group (C6H5-) | 0.0049 | 0.0049

MolWt| * | Molecular Weight Parameter | | -0.2976

Const| * | Equation Constant | | 3.8477

============+============================================+=========+=========

RESULT | Biowin4 (Survey Model - Primary Biodeg) | | 3.9845

============+============================================+=========+=========

Result Classification: 5.00 -> hours 4.00 -> days 3.00 -> weeks

(Primary & Ultimate) 2.00 -> months 1.00 -> longer

------+-----+--------------------------------------------+---------+---------

TYPE | NUM | Biowin5 FRAGMENT DESCRIPTION | COEFF | VALUE

------+-----+--------------------------------------------+---------+---------

Frag | 1 | Ester [-C(=O)-O-C] | 0.3437 | 0.3437

Frag | 1 | Aromatic-CH2 | -0.0557 | -0.0557

Frag | 5 | Aromatic-H | 0.0082 | 0.0411

Frag | 1 | Methyl [-CH3] | 0.0004 | 0.0004

Frag | 4 | -CH2- [linear] | 0.0494 | 0.1977

MolWt| * | Molecular Weight Parameter | | -0.6137

Const| * | Equation Constant | | 0.7121

============+============================================+=========+=========

RESULT | Biowin5 (MITI Linear Biodeg Probability) | | 0.6256

============+============================================+=========+=========

------+-----+--------------------------------------------+---------+---------

TYPE | NUM | Biowin6 FRAGMENT DESCRIPTION | COEFF | VALUE

------+-----+--------------------------------------------+---------+---------

Frag | 1 | Ester [-C(=O)-O-C] | 2.4462 | 2.4462

6

Frag | 1 | Aromatic-CH2 | -0.1246 | -0.1246

Frag | 5 | Aromatic-H | 0.1201 | 0.6007

Frag | 1 | Methyl [-CH3] | 0.0194 | 0.0194

Frag | 4 | -CH2- [linear] | 0.4295 | 1.7180

MolWt| * | Molecular Weight Parameter | | -5.9553

============+============================================+=========+=========

RESULT |Biowin6 (MITI Non-Linear Biodeg Probability)| | 0.7738

============+============================================+=========+=========

A Probability Greater Than or Equal to 0.5 indicates --> Readily Degradable

A Probability Less Than 0.5 indicates --> NOT Readily Degradable

------+-----+--------------------------------------------+---------+---------

TYPE | NUM | Biowin7 FRAGMENT DESCRIPTION | COEFF | VALUE

------+-----+--------------------------------------------+---------+---------

Frag | 1 | Linear C4 terminal chain [CCC-CH3] | -0.3177 | -0.3177

Frag | 1 | Ester [-C(=O)-O-C] | 0.1719 | 0.1719

Frag | 1 | Alkyl substituent on aromatic ring | -0.1145 | -0.1145

Frag | 1 | Unsubstituted phenyl group (C6H5 -) | 0.2182 | 0.2182

Frag | 1 | Aromatic-CH2 | -0.0073 | -0.0073

Frag | 5 | Aromatic-H | -0.0954 | -0.4772

Frag | 1 | Methyl [-CH3] | -0.0796 | -0.0796

Frag | 4 | -CH2- [linear] | 0.0260 | 0.1040

Const| * | Equation Constant | | 0.8361

============+============================================+=========+=========

RESULT | Biowin7 (Anaerobic Linear Biodeg Prob) | | 0.3338

============+============================================+=========+=========

A Probability Greater Than or Equal to 0.5 indicates --> Biodegrades

Ready Biodegradability Prediction: (YES or NO)

----------------------------------------------

Criteria for the YES or NO prediction: If the Biowin3 (ultimate survey

model) result is "weeks" or faster (i.e. "days", "days to weeks", or

"weeks" AND the Biowin5 (MITI linear model) probability is >= 0.5, then

the prediction is YES (readily biodegradable). If this condition is not

satisfied, the prediction is NO (not readily biodegradable). This method

is based on application of Bayesian analysis to ready biodegradation data

(see Help). Biowin5 and 6 also predict ready biodegradability, but for

degradation in the OECD301C test only; using data from the Chemicals

Evaluation and Research Institute Japan (CERIJ) database.

Validity criteria fulfilled:

not specified

Interpretation of results:

readily biodegradable

Conclusions:

The biodegradability of the test substance pentyl 2-phenylacetate was estimated by using seven different Biowin 1-7 models of the BIOWIN v4.10 software. The results indicate that the test chemical pentyl 2-phenylacetate is readily biodegradable.

Executive summary:

Estimation Programs Interface Suite (EPI suite, 2017) was run to predict the biodegradation potential of the test compound pentyl 2 -phenylacetate (CAS no. 5137 -52 -0) 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 test chemical pentyl 2 -phenylacetate is readily biodegradable.

Description of key information

Biodegradability of test chemical pentyl-2- phenylacetate is predicted using OECD QSAR tool box v.3.3 using log Kow as primary descriptor. The test chemical pentyl-2-phenylacetate showed 90.800 % biodegradability in 28 days by considering BOD as a parameter and microrganisms as a inoculum therefore it is concluded that this test chemical pentyl-2-phenylacetate is readily biodegradable.

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Additional information

Two different predicted data study for target chemical pentyl 2- phenylacetate ( CAS No. 5137 -52 -0) and supporting weight of studies for its read across chemicals were reviwed for the biodegrdation endpoint which are summarized as below.

Biodegradability of test chemical pentyl-2- phenylacetate is predicted using OECD QSAR tool box v.3.3 using log Kow as primary descriptor. The test chemical pentyl-2-phenylacetate showed 90.800 % biodegradability in 28 days by considering BOD as a parameter and microrganisms as a inoculum therefore it is concluded that this test chemical pentyl-2-phenylacetate is readily biodegradable.

Another prediction is done by using Estimation Programs Interface Suite (EPI suite, 2017).The biodegradation potential of the test compound pentyl 2 -phenylacetate (CAS no. 5137 -52 -0) 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 test chemical pentyl 2 -phenylacetate is considered to be readily biodegradable.

In a supporting weight of evidence of the Ready Biodegradability of read across chemical Benzyl Butyrate( CAS no. 103-37-7) was determined by the Manometric respirometry method by Givaudan Suisse SA Ecotoxicological Laboratory, 5, ch. de la Parfumerie,CH-1214 Vernier/Geneva, Switzerland, Sustainability Support Service (Europe) AB laboratory with acess rights from Givaudan-Regulatory Affairs and Product Safety, Company study no.11-E225, 2011).

The method used is basically the one described under No.301 F in the OECD Guidelines for testing of Chemicals. A measured volume of inoculated mineral medium, containing a known concentration of read across substance 30 mg/L as the nominal sole source of organic carbon, is stirred in a closed flask at a constant  temperature   (± 1°C) for up to 28 days. Evolved carbon dioxide is absorbed in sodium hydroxide pellets. The consumption of oxygen is determined by measuring the pressure drop in the respirometer  flask.  The Biological   Oxygen Demand (BOD), amount of oxygen taken up by the microbial population during biodegradation of the read across chemical benzyl butyrate (corrected for uptake by blank inoculum, run in parallel) is expressed as a percentage  of ThOD (Theoretical   Oxygen Demand,  calculated   from the elemental composition, assuming that carbon is oxidized to carbon dioxide,  hydrogen to water and nitrogen to ammonium, nitrite or nitrate). Benzyl Butyrate undergoes 88% biodegradation after 28 days (87% after 62 days) in the test conditions. The10-day window criterion is also fulfilled (20% biodegradation on day 1 and 77% on day 11). Thus, Benzyl Butyrate should be regarded as readily biodegradable according to this test. Benzyl Butyrate did not inhibit the intrinsic respiration of the inoculum at the test concentration and was therefore considered to be non-toxic to the inoculum at the test concentration.

In another supporting weight of evidence study from journal Chemosphere (vol 23. 1991) by author R R Birch and R J Fletcher under the title "The Application of Dissolved Inorganic Carbon Measurements to the Study of Aerobic Biodegradability” biodegradability of read across chemical benzyl acetate (CAS no. 140-11-4) was determined by 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 test 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 test 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, Control vessel were also measured similarly. The difference in the total inorganic carbon determined in the benzyl acetate containing vessel and control vessels allows the quantity of carbon dioxide produced from the read across 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 read across substance conc.

The percentage biodegradation of read across chemical benzyl acetate 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 chemical benzyl acetate was determined to be readily biodegradable.

On the basis of results of above mentioned studies for target chemical pentyl-2 -phenylacetate (from OECD QSAR tool boxv3.3 and EPI suite) and supporting weight of evidence study ( from Givaudan Suisse SA Ecotoxicological Laboratory report 2017 and Chemosphere Journal 1991). It is concluded that the test chemical pentyl-2- phenyl acetate can be expected to be readily biodegradable.