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Environmental fate & pathways

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Description of key information

Biodegradation in water

The ready biodegradability of Phenylethyl salicylat (CAS no. 87 -22 -9) was determined by the OECD Guideline 301 F (Ready Biodegradability: Manometric Respirometry Test)

(SSS (Sustainability Support Services) has a letter of access, 2000). Fresh activated sludge from a biological waste water treatment plant treating predominantly domestic sewage was used. The sludge is collected in the morning, washed three times in the mineral medium (by centrifuging at 1000 g for 10 minutes, discarding the supernant and resuspending in mineral medium) and kept aerobic until being used on the same day. Initial test substance concentration used in the study was 100 mg/l. Mineral medium was prepared by mixing 50 ml of solution A and 2000 ml deionised water, adding 5 ml of each of the solutions B, C and D and making up to 5 litres with deionised water. The pH is measured and if necessary adjusted to 7.4 +/- 0.2 with phosphoric acid or potassium hydroxide. The water used during this study is deionised water containing less than 10 mg/l dissolved organic carbon. Suspended solids concentration used in the study was 3.289 g/l. To obtain a concentration of inoculum of 30 mg/l (dry weight) in a 250 ml flask, 2.28 ml of sludge is needed (inoculum). Sodium benzoate (100 mg/l) (purity min. 99.0%) was used as a reference substance for the study. Degradation of sodium benzoate exceeded 40% after 7 days and 65% after 14 days, the activity of the inoculum was thus verified and the test is considered as valid. Phenylethyl salicylate undergoes 93% biodegradation after 28 days in the test conditions. Biodegradation starts on day 3 and reached 80% at the end of the 10-day window (day 3 to 13). The curves obtained with the reference substance alone and with Phenylethyl salicylate plus reference substance show no toxic effect of Phenylethyl salicylate to the micro-organisms at the test concentration (100 mg/l). Thus, Phenylethyl salicylate should be regarded as readily biodegradable according to this test.

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 2-hydroxybenzoate (CAS No. 87 -22 -9). If released in to the environment, 22.1% of the chemical will partition into water according to the Mackay fugacity model level III and the half-life period of 2-phenylethyl 2-hydroxybenzoate in water is estimated to b 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 moderate to low whereas the half-life period of 2-phenylethyl 2-hydroxybenzoate in sediment is estimated to be 135 days (3240 hrs). However, as the percentage release of test chemical into the sediment is less than 5% (i.e, reported as 4.02%), indicates that 2-phenylethyl 2-hydroxybenzoate is not persistent in sediment.

 

Biodegradation in soil

The half-life period of 2-phenylethyl 2-hydroxybenzoate (CAS No. 87 -22 -9) 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, 73% of the chemical will partition into soil according to the Mackay fugacity model level III. The half-life period of 2-phenylethyl 2-hydroxybenzoate in soil is estimated to be 30 days (720 hrs). Based on this half-life value of 2-phenylethyl 2-hydroxybenzoate, it is concluded that the chemical 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 key study for the target compound 2-phenylethyl 2-hydroxybenzoate (CAS No. 87-22-9) and supporting study for its read across substance were reviewed for the biodegradation end point which are summarized as below:

 

The ready biodegradability of test chemical Phenylethyl salicylat (CAS no. 87 -22 -9) was determined by the OECD Guideline 301 F (Ready Biodegradability: Manometric Respirometry Test) at Givuadan Roure SA Ecotoxicological Laboratory, Switzerland (SSS (Sustainability Support Services) has a letter of access, 2000). Fresh activated sludge from a biological waste water treatment plant treating predominantly domestic sewage was used. The sludge is collected in the morning, washed three times in the mineral medium (by centrifuging at 1000 g for 10 minutes, discarding the supernant and resuspending in mineral medium) and kept aerobic until being used on the same day. Initial test substance concentration used in the study was 100 mg/l. Mineral medium was prepared by mixing 50 ml of solution A and 2000 ml deionised water, adding 5 ml of each of the solutions B, C and D and making up to 5 litres with deionised water. The pH is measured and if necessary adjusted to 7.4 +/- 0.2 with phosphoric acid or potassium hydroxide. The water used during this study is deionised water containing less than 10 mg/l dissolved organic carbon. Suspended solids concentration used in the study was 3.289 g/l. To obtain a concentration of inoculum of 30 mg/l (dry weight) in a 250 ml flask, 2.28 ml of sludge is needed (inoculum). Sodium benzoate (100 mg/l) (purity min. 99.0%) was used as a reference substance for the study. Degradation of sodium benzoate exceeded 40% after 7 days and 65% after 14 days, the activity of the inoculum was thus verified and the test is considered as valid. Phenylethyl salicylate undergoes 93% biodegradation after 28 days in the test conditions. Biodegradation starts on day 3 and reached 80% at the end of the 10-day window (day 3 to 13). The curves obtained with the reference substance alone and with Phenylethyl salicylate plus reference substance show no toxic effect of Phenylethyl salicylate to the micro-organisms at the test concentration (100 mg/l). Thus, Phenylethyl salicylate should be regarded as readily biodegradable according to this test.

 

In a supporting weight of evidence study from authoritative database (J-CHECK, HSDB 2017 and Envichem, 2014) for the read across chemical Acetic acid, phenylmethyl ester (CAS no. 140-11-4), biodegradation experiment was conducted for 28 days for evaluating the percentage biodegradability of read across substance Acetic acid, phenylmethyl ester. 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 Acetic acid, phenylmethyl ester was determined to be 95, 98 and 100% by BOD, TOC removal and GC parameter in 28 days. The test substance was partially hydrolyzed in water to form Benzyl alcohol and acetic acid. Thus, based on percentage degradation, Acetic acid, phenylmethyl ester is considered to be readily biodegradable in nature.

On the basis of above results for target chemical 2 -phenylethyl 2 -hydroxybenzoate (from experimental study report, 2000) and for its read across substance (from authoritative database J-CHECK, HSDB and Envichem), it can be concluded that the test substance 2 -phenylethyl 2 -hydroxybenzoate 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 2-hydroxybenzoate (CAS No. 87 -22 -9). If released in to the environment, 22.1% of the chemical will partition into water according to the Mackay fugacity model level III and the half-life period of 2-phenylethyl 2-hydroxybenzoate in water is estimated to b 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 moderate to low whereas the half-life period of 2-phenylethyl 2-hydroxybenzoate in sediment is estimated to be 135 days (3240 hrs). However, as the percentage release of test chemical into the sediment is less than 5% (i.e, reported as 4.02%), indicates that 2-phenylethyl 2-hydroxybenzoate is not persistent in sediment.

 

Biodegradation in soil

The half-life period of 2-phenylethyl 2-hydroxybenzoate (CAS No. 87 -22 -9) 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, 73% of the chemical will partition into soil according to the Mackay fugacity model level III. The half-life period of 2-phenylethyl 2-hydroxybenzoate in soil is estimated to be 30 days (720 hrs). Based on this half-life value of 2-phenylethyl 2-hydroxybenzoate, it is concluded that the chemical 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 2-hydroxybenzoate can be considered to be readily biodegradable in nature.