Pentyl phenylacetate

Endpoint summary

Description of key information

Biodegradation in water:

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.

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 pentyl 2-phenylacetate (CAS No. 5137 -52 -0). If released in to the environment, 22.3 % of the chemical will partition into water according to the Mackay fugacity model level III and the half-life period of the chemical pentyl 2-phenylacetate in water is estimated to be 15 days (360 hrs). The half-life (15 days estimated by EPI suite) indicates that the chemical is not persistent in water and the exposure risk to aquatic animals is low whereas the half-life period of pentyl 2-phenylacetate in sediment is estimated to be 135 days (3240 hrs).

However, as the percentage release of test chemical into the sediment is less than 2 % (i.e, reported as 1.01%), indicates that test chemical pentyl 2 -phenylacetate is not persistent in sediment.

Biodegradation in soil:

The half-life period of pentyl 2 -phenylacetate (CAS No.5137 -52 -0) in soil was estimated using Level III Fugacity Model by EPI Suite version 4.1 estimation database (EPI suite, 2017). If released into the environment, 65.3 % of the chemical will partition into soil according to the Mackay fugacity model level III. The half-life period of pentyl 2 -phenylacetate in soil is estimated to be 30 days ( 720 hrs). Based on this half-life value of pentyl 2 -phenylacetate, it is concluded that the chemical is not persistent in the soil environment and the exposure risk to soil dwelling animals is low.

Additional information

Biodegradation in water:

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 box v3.3 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.

Biodegradation in water and Sediments:

Estimation Programs Interface (EPI Suite, 2017) prediction model was run to predict the half-life in water and sediment for the test compound pentyl 2-phenylacetate (CAS No. 5137 -52 -0). If released in to the environment, 22.3 % of the chemical will partition into water according to the Mackay fugacity model level III and the half-life period of the chemical pentyl 2-phenylacetate in water is estimated to be 15 days (360 hrs). The half-life (15 days estimated by EPI suite) indicates that the chemical is not persistent in water and the exposure risk to aquatic animals is low whereas the half-life period of pentyl 2-phenylacetate in sediment is estimated to be 135 days (3240 hrs).

However, as the percentage release of test chemical into the sediment is less than 2 % (i.e, reported as 1.01%), indicates that test chemical pentyl 2 -phenylacetate is not persistent in sediment.

Biodegradation in soil:

The half-life period of pentyl 2 -phenylacetate (CAS No.5137 -52 -0) in soil was estimated using Level III Fugacity Model by EPI Suite version 4.1 estimation database (EPI suite, 2017). If released into the environment, 65.3 % of the chemical will partition into soil according to the Mackay fugacity model level III. The half-life period of pentyl 2 -phenylacetate in soil is estimated to be 30 days ( 720 hrs). Based on this half-life value of pentyl 2 -phenylacetate, it is concluded that the chemical is not persistent in the soil environment and the exposure risk to soil dwelling animals is low.