Phenethyl propionate

Endpoint summary

Description of key information

Biodegradation in water

Biodegradation study was conducted for 30 days for evaluating the percentage biodegradability of test substance 2 -phenylethyl propanoate (Dingfue Hu and Joel Coats, 2008 &

Dingfue Hu, 2007). 3H-phenethyl propionate were purchased from PerkinElmer Life Sciences and Analytical Sciences. (Boston, MA, USA). Analytical standards of phenethyl propionate, 2-phenylethanol, 2-(4-hydroxyphenyl) ethanol were purchased from Lancaster Synthesis, Inc. Methanol was purchased from Fisher Scientific Solvents used for extraction and chromatographic analysis were analytical reagent grade or better. Monophase® S scintillation cocktails were purchased from PerkinElmer Life and Analytical Sciences.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 in the pond water. 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” incubationsfrom 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’st-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 test substance2-phenylethyl propanoatewas determined to be50% in 5 days.Thus, based on percentage degradation,2-phenylethyl propanoateis considered to be readily biodegradable in nature.

Biodegradation in water and sediment

Estimation Programs Interface (EPI Suite, 2017) prediction model was run to predict the half-life in water and sediment for the test compound 2-phenylethyl propanoate (CAS No. 122 -70 -3). If released in to the environment, 24.9 % of the chemical will partition into water according to the Mackay fugacity model level III and the half-life period of 2-phenylethyl propanoate in water is estimated to be 15 days (360 hrs). The half-life (15 days estimated by EPI suite) indicates that the chemical 2-phenylethyl propanoate is not persistent in water and the exposure risk to aquatic animals is moderate to low whereas the half-life period of 2-phenylethyl propanoate in sediment is estimated to be 135 days (3240 hrs). However, as the percentage release of test chemical into the sediment is less than 1% (i.e, reported as 0.406%), indicates that 2-phenylethyl propanoate is not persistent in sediment.

 

Biodegradation in soil

Biodegradation study was conducted for 30 days for evaluating the percentage biodegradability of test substance 2-phenylethyl propanoate (Dingfue Hu and Joel Coats, 2008 &

Dingfue Hu, 2007). 3H-phenethyl propionate were purchased from PerkinElmer Life Sciences and Analytical Sciences. (Boston, MA, USA). Analytical standards of phenethyl propionate, 2-phenylethanol, 2-(4-hydroxyphenyl) ethanol were purchased from Lancaster Synthesis, Inc. Methanol was purchased from Fisher Scientific Solvents used for extraction and chromatographic analysis were analytical reagent grade or better. Monophase® S scintillation cocktails were purchased from PerkinElmer Life and Analytical Sciences.Initial test substance conc. used for the study was 10μg/g. Soil was collected at the Iowa State University Agronomy and Agricultural Engineering Research Farm near Ames, Iowa [Field 55].The soil contained 1.6% organic matter, 60% sand, 22% silt, 18% clay, and pH 7.0. Soil (50g) was kept in a 250-ml French square bottle, and soil moisture content was adjusted to 75% of 1/3 bar moisture.The temperature was maintained at 25 ± 2°C. Soil samples were treated with 3HPEP in methanol at 10 μg/g. Bottles were sealed with Teflon® caps. Polyurethane foam was suspended above the treated soils inside each bottle to capture volatile compounds. Polyurethane foam was changed biweekly. 1.5g of Drierite® (anhydrous calcium sulfate) was used to trap tritium H2O in the air in the container. Drierite was changed when it turned pink. Soil sampling times were at pre-treatment, at 1, 3, 7, 14, and 30 days 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). Soil samples (50 g) were extracted with methanol/distilled water (95:5) three times, and the resulting extracts were pooled. Filtered samples were directly injected for HPLC analysis. HPLC fractions were collected for liquid scintillation counting (LSC). Drierite and polyurethane foam were thoroughly extracted with methanol, and the resulting extracts were subjected to LSC to measure trapped radioactivity. Non-extractable radioactive residues in soil were measured by soil combustion using a Packard sample oxidizer. A 0.5-g soil sample was incorporated into a cellulose pellet, and three replications were performed for each treatment.Dissipation rates of PEP were calculated using first-order open models. A student’st-test was used to compare dissipation rates of PEP in light and in dark from the water dissipation studies.The half-life of test substance2-phenylethyl propanoate was determined to be4 days.The degradation product of chemical 2-phenylethyl propanoate were 2-Phenylethanol and 2-(4-hydroxyphenyl) ethanol, respectively. 2-Phenylethanol reached the maximal concentration in 1 week both in water and in soil; however, the peak in soil was 36% of total radioactivity compared to 74% of total radioactivity in water. The formation of 2-(4-hydroxyphenyl) ethanol was also less in soil than in water.The average radioactivity as bound residues remained below 6%, and mineralization was less than 3%.Based on this half-life value of test chemical 2-phenylethyl propanoate (i.e 4 days), it is concluded that the chemical 2-phenylethyl propanoate is not persistent in the soil environment and the exposure risk to soil dwelling animals is moderate to low.

Additional information

Biodegradation in water

Experimental study and predicted data for the target compound 2-phenylethyl propanoate (CAS No. 122-70-3) and various supporting studies for its read across substance were reviewed for the biodegradation end point which are summarized as below:

 

In an experimental key study from peer reviewed journal (Dingfue Hu and Joel Coats, 2008) and review article (Dingfue Hu, 2007), biodegradation experiment was conducted for 30 days for evaluating the percentage biodegradability of test substance 2 -phenylethyl propanoate (CAS no. 122-70-3). 3H-phenethyl propionate were purchased from PerkinElmer Life Sciences and Analytical Sciences. (Boston, MA, USA). Analytical standards of phenethyl propionate, 2-phenylethanol, 2-(4-hydroxyphenyl) ethanol were purchased from Lancaster Synthesis, Inc. Methanol was purchased from Fisher Scientific Solvents used for extraction and chromatographic analysis were analytical reagent grade or better. Monophase® S scintillation cocktails were purchased from PerkinElmer Life and Analytical Sciences. 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 in the pond water. 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’st-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 test substance2-phenylethyl propanoate was determined to be50% in 5 days. Thus, based on percentage degradation,2-phenylethyl propanoate is considered to be readily biodegradable in nature.

 

In a prediction using the Estimation Programs Interface Suite (EPI suite, 2017), the biodegradation potential of the test compound2-phenylethyl propanoate(CAS No. 122-70-3) 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 2-phenylethyl propanoate is expected to be readily biodegradable.

 

For the read across chemical Benzyl Butyrate (CAS no. 103-37-7), the Ready Biodegradability of Benzyl Butyrate was determined by the Manometric respirometry(Study report Sustainability Support Service (Europe) AB with access 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 test 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 test chemical (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 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. 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 day1 and 77% on day11). Thus, Benzyl Butyrate should be regarded as readily biodegradable according to this test.

 

Another biodegradation study for 28-days Manometric respirometry test following the OECD guideline 301F was conducted for determining the ready biodegradability of the read across chemical Benzyl butyrate (CAS No. 103-37-7) [UERLStudy Report, Sustainability Support Services (Europe) AB (Report no.103-37-7/01/2015/RBD), 2015]. % Degradation was calculated using the values of BOD and ThOD for test item and reference item. The BOD₂₈value of Benzyl butyrate (CAS No. 103-37-7) was observed to be 1.967 mgO₂/mg. ThOD was calculated as 2.424 mgO₂/mg. Accordingly, the % degradation of the read across item after 28 days of incubation at 20 ± 1°C according to manometric respirometry test was determined to be 81.15%. Based on the results, chemical Benzyl butyrate, under the test conditions, was considered to be readily-Biodegradable at 20 ± 1°C over a period of 28 days.

In a supporting study from authoritative database (J-CHECK, HSDB, 2017 and Envichem, 2014) for the read across chemical 2-phenylethan-1-ol (CAS no. 60-12-8),biodegradation experiment was conducted for 14 days for evaluating the percentage biodegradability of read across substance 2-phenylethan-1-ol.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 substance 2-phenylethan-1-ol was determined to be 87, 95 and 100% by BOD, TOC removal and GC parameter in 14 days. Thus, based on percentage degradation, 2-phenylethan-1-ol is considered to be readily biodegradable in nature.

On the basis of above results for target chemical 2-phenylethyl propanoate (from peer reviewed journal and EPI suite, 2017) and for its read across substance (from study reports and authoritative database J-CHECK, HSDB, 2017 and Envichem, 2014), it can be concluded that the test substance 2-phenylethyl propanoate can be expected to be readily biodegradable in nature.

Biodegradation in water and sediment

Estimation Programs Interface (EPI Suite, 2017) prediction model was run to predict the half-life in water and sediment for the test compound 2-phenylethyl propanoate (CAS No. 122 -70 -3). If released in to the environment, 24.9 % of the chemical will partition into water according to the Mackay fugacity model level III and the half-life period of 2-phenylethyl propanoate in water is estimated to be 15 days (360 hrs). The half-life (15 days estimated by EPI suite) indicates that the chemical 2-phenylethyl propanoate is not persistent in water and the exposure risk to aquatic animals is moderate to low whereas the half-life period of 2-phenylethyl propanoate in sediment is estimated to be 135 days (3240 hrs). However, as the percentage release of test chemical into the sediment is less than 1% (i.e, reported as 0.406%), indicates that 2-phenylethyl propanoate is not persistent in sediment.

 

Biodegradation in soil

Biodegradation study was conducted for 30 days for evaluating the percentage biodegradability of test substance 2-phenylethyl propanoate (Dingfue Hu and Joel Coats, 2008 &

Dingfue Hu, 2007). 3H-phenethyl propionate were purchased from PerkinElmer Life Sciences and Analytical Sciences. (Boston, MA, USA). Analytical standards of phenethyl propionate, 2-phenylethanol, 2-(4-hydroxyphenyl) ethanol were purchased from Lancaster Synthesis, Inc. Methanol was purchased from Fisher Scientific Solvents used for extraction and chromatographic analysis were analytical reagent grade or better. Monophase® S scintillation cocktails were purchased from PerkinElmer Life and Analytical Sciences.Initial test substance conc. used for the study was 10μg/g. Soil was collected at the Iowa State University Agronomy and Agricultural Engineering Research Farm near Ames, Iowa [Field 55].The soil contained 1.6% organic matter, 60% sand, 22% silt, 18% clay, and pH 7.0. Soil (50g) was kept in a 250-ml French square bottle, and soil moisture content was adjusted to 75% of 1/3 bar moisture.The temperature was maintained at 25 ± 2°C. Soil samples were treated with 3HPEP in methanol at 10 μg/g. Bottles were sealed with Teflon® caps. Polyurethane foam was suspended above the treated soils inside each bottle to capture volatile compounds. Polyurethane foam was changed biweekly. 1.5g of Drierite® (anhydrous calcium sulfate) was used to trap tritium H2O in the air in the container. Drierite was changed when it turned pink. Soil sampling times were at pre-treatment, at 1, 3, 7, 14, and 30 days 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). Soil samples (50 g) were extracted with methanol/distilled water (95:5) three times, and the resulting extracts were pooled. Filtered samples were directly injected for HPLC analysis. HPLC fractions were collected for liquid scintillation counting (LSC). Drierite and polyurethane foam were thoroughly extracted with methanol, and the resulting extracts were subjected to LSC to measure trapped radioactivity. Non-extractable radioactive residues in soil were measured by soil combustion using a Packard sample oxidizer. A 0.5-g soil sample was incorporated into a cellulose pellet, and three replications were performed for each treatment.Dissipation rates of PEP were calculated using first-order open models. A student’st-test was used to compare dissipation rates of PEP in light and in dark from the water dissipation studies.The half-life of test substance2-phenylethyl propanoate was determined to be4 days.The degradation product of chemical 2-phenylethyl propanoate were 2-Phenylethanol and 2-(4-hydroxyphenyl) ethanol, respectively. 2-Phenylethanol reached the maximal concentration in 1 week both in water and in soil; however, the peak in soil was 36% of total radioactivity compared to 74% of total radioactivity in water. The formation of 2-(4-hydroxyphenyl) ethanol was also less in soil than in water.The average radioactivity as bound residues remained below 6%, and mineralization was less than 3%.Based on this half-life value of test chemical 2-phenylethyl propanoate (i.e 4 days), it is concluded that the chemical 2-phenylethyl propanoate is not persistent in the soil environment and the exposure risk to soil dwelling animals is moderate to low.

On the basis of available information, the test substance 2 -phenylethyl propanoate can be considered to be readily biodegradable in nature.