1-phenylethanol

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

data from handbook or collection of data

Justification for type of information:

Data is from HSDB and PubChem authoritative database

Qualifier:

according to guideline

Guideline:

other: as mentioned below

Principles of method if other than guideline:

Biodegradation study was conducted for 20 days for evaluating the percentage biodegradability of test substance 1-phenylethan-1-ol.

GLP compliance:

not specified

Specific details on test material used for the study:

- Name of test material (IUPAC name): 1-phenylethan-1-ol
- Common name: alpha-methylbenzyl alcohol
- Molecular formula: C12H12O
- Molecular weight: 122.166 g/mol
- Smiles notation: c1(ccccc1)C(C)O
- InChl: 1S/C8H10O/c1-7(9)8-5-3-2-4-6-8/h2-7,9H,1H3
- Substance type: Organic
- Physical state: Liquid

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge (adaptation not specified)

Duration of test (contact time):

20 d

Initial conc.:

100 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

test mat. analysis

Remarks:

(%degradation)

Key result

Parameter:

% degradation (test mat. analysis)

Value:

100

Sampling time:

20 d

Remarks on result:

other: Other details not known

Details on results:

Test substance undergoes 100% degradation in 14 or 20 days, depending on the inoculum size (heavy or light, respectively). Acetophenone was obtained as the major metabolite.

Validity criteria fulfilled:

not specified

Interpretation of results:

readily biodegradable

Conclusions:

The percentage degradation of test substance 1-phenylethan-1-ol was determined to be approx. 100% in 14 or 20 days. Thus, based on percentage degradation, 1-phenylethan-1-ol is considered to be readily biodegradable in water.

Executive summary:

Biodegradation study was conducted for 20 days for evaluating the percentage biodegradability of test substance1-phenylethan-1-ol (CAS no. 98-85-1). The study was performedunder aerobic conditions.Activated sludge was used as a test inoculums for the study. Initial test substance conc. used in the study was 100 mg/l. The percentage degradation of test substance 1-phenylethan-1-ol was determined to be approx. 100% in 14 or 20 days, depending on the inoculum size (heavy or light, respectively). Acetophenone was obtained as the major metabolite. Thus, based on percentage degradation, 1-phenylethan-1-ol is considered to be readily biodegradable in nature.

Description of key information

Biodegradation study was conducted for 20 days for evaluating the percentage biodegradability of test substance1-phenylethan-1-ol (CAS no. 98-85-1) (HSDB and PubChem, 2017). The study was performedunder aerobic conditions.Activated sludge was used as a test inoculums for the study. Initial test substance conc. used in the study was 100 mg/l. The percentage degradation of test substance 1-phenylethan-1-ol was determined to be approx. 100% in 14 or 20 days, depending on the inoculum size (heavy or light, respectively). Acetophenone was obtained as the major metabolite. Thus, based on percentage degradation, 1-phenylethan-1-olis considered to be readily biodegradable in nature.

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Additional information

Various experimental key and supporting studies for the target compound 1-phenylethan-1-ol (CAS No. 98-85-1) were reviewed for the biodegradation end point which are summarized as below:

 

In an experimental key study from authoritative databases (HSDB and PubChem, 2017),biodegradation experiment was conducted for 20 days for evaluating the percentage biodegradability of test substance 1-phenylethan-1-ol (CAS no. 98-85-1). The study was performed under aerobic conditions. Activated sludge was used as a test inoculums for the study. Initial test substance conc. used in the study was 100 mg/l. The percentage degradation of test substance 1-phenylethan-1-ol was determined to be approx. 100% in 14 or 20 days, depending on the inoculum size (heavy or light, respectively). Acetophenone was obtained as the major metabolite. Thus, based on percentage degradation, 1-phenylethan-1-ol is considered to be readily biodegradable in nature.

 

Another biodegradation study from peer reviewed journal (H. Heukelekian et. al., 1955) and secondary source (2017) was conducted for 10 days for evaluating the percentage biodegradability of test substance 1-phenylethan-1-ol (CAS no. 98-85-1) using standard dilution method under aerobic conditionsat a temperature of 20°C. Sewage was used as a test inoculum. The percentage degradation of test substance 1-phenylethan-1-ol was determined to be 38% by BOD parameter in 10 days and BOD 10 day value was determined to be 1 g/g, respectively. Thus, based on percentage degradation, 1-phenylethan-1-ol is considered to be readily biodegradable in nature.

 

In a supporting study,28-days Closed Bottle test following the OECD guideline 301 D to determine the ready biodegradability of the test item 1-phenylethan-1-ol (CAS No.98-85-1) (Experimental study report, 2018). The study was performed at a temperature of 20°C. The test system included control, test item and reference item. Polyseed were used for this study. 1 polyseed capsule were added in 500 ml D.I water and then stirred for 1 hour for proper mixing and functioning of inoculum. This gave the bacterial count as 10E7 to 10E8 CFU/ml. At the regular interval microbial plating was also performed on agar to confirm the vitality and CFU count of microorganism. The concentration of test and reference item (Sodium Benzoate) chosen for both the study was 4 mg/L, while that of inoculum was 32 ml/l . OECD mineral medium was used for the study. ThOD (Theoretical oxygen demand) of test and reference item was determined by calculation. % degradation was calculated using the values of BOD and ThOD for test item and reference item. The % degradation of procedure control (reference item) was also calculated using BOD & ThOD and was determined to be 76.5%. Degradation of Sodium Benzoate exceeds 39.15% on 7 days & 70.48% on 14th day. The activity of the inoculum was thus verified and the test can be considered as valid. The BOD28 value of test chemical was observed to be 1.22 mgO2/mg. ThOD was calculated as 2.61 mgO2/mg. Accordingly, the % degradation of the test item 1-phenylethan-1-ol after 28 days of incubation at 20 ± 1°C according to Closed Bottle test was determined to be 46.74%. Based on the results, the test item, under the test conditions, was considered to be ultimate inherently biodegradable in nature.

 

Additional biodegradation study (from authoritative databases (HSDB and PubChem, 2017) and secondary source (2017) was conducted for evaluating the percentage biodegradability of test substance 1-phenylethan-1-ol (CAS no. 98-85-1). The study was performedaccording to sewage die-away screening test under aerobic conditions. Sewage was used as a test inoculums for the study. Initial test substance conc. used in the study was 6000 mg/l. The percentage degradation of test substance 1-phenylethan-1-ol was determined to be 50 and 78.2% using BOD parameter in 0.6 and 8-10 days, respectively. Thus, based on percentage degradation, 1-phenylethan-1-ol is considered to be readily biodegradable in nature.

 

In an another supporting study from authoritative database (2017),biodegradation experiment was conducted for evaluating the percentage biodegradability of test substance 1-phenylethan-1-ol (CAS no. 98-85-1). The study was performed under anaerobic conditions. Digested sludge was used as a test inoculums for the study. The percentage degradation of test substance 1-phenylethan-1-ol was determined to be 50% in 7 days. Acetophenone was obtained as the metabolite. Thus, based on percentage degradation, 1-phenylethan-1-ol is considered to be readily biodegradable in nature.

 

For the target chemical 1-phenylethan-1-ol(CAS No. 98-85-1) from authoritative database (2017),Biodegradation study was conducted for 32 days for evaluating the percentage biodegradability of test substance 1-phenylethan-1-ol (CAS no. 98-85-1). The study was performed under aerobic conditions. Mixed microbial culture was used as a test inoculums for the study. Initial test substance conc. used in the study was 550 mg/l. Although percentage degradation of test substance 1-phenylethan-1-ol not known, but conc. of test chemical was reduced from conc. 550 mg/l to 20 mg/l in 32 days using mixed microbial culture as test inoculum. Thus, based on this, chemical 1-phenylethan-1-ol is considered to be readily biodegradable in nature.

 

Another biodegradation study was conducted for 210 mins for evaluating the percentage biodegradability of test substance 1-phenylethan-1-ol (CAS no. 98-85-1) (Cecil W. Chambers et. al., 1963). Micro-organisms (mixture of several species with pseudomonads predominating) was used as a test inoculum for the study. The biodegradation study was performed at a temperature of 30°C. Test inoculum bacteria was isolated from different sources which includes soil, compost, or mud from a catalytic cracking plant waste lagoon. The test organism were grown on mineral salts medium with vitamin B12 added. The only source of carbon was 300 mg/l phenol. The cells were washed and centrifuged three times with the phosphate buffer dilution water and stored overnight at 5°C in the phosphate buffer dilution water. The next morning after storage they were aerated for 3 hr, removed by centrifugation, and resuspended in 0.067 M phosphate buffer at pH 7.2. The stock solution of substrates were prepared from chemical designated as highest purity. Test chemical concentration used for the study was 60 mg/l. Cell suspension was omitted from one flask to show whether any of the substrate was lost because of chemical oxidation. An endogenous control and a parallel test with phenol were always included in each experiment to show that the bacterial suspension has a normally high capacity to utilize phenol. A spectrophotometer was used to compare the concentration of substrate remaining in the centrifuged supernatant from the respirometric tests directly with the known concentration of the test compound. Test chemical was determined by the 4-amino-antipyridine method at 510 mµ. The oxygen uptake (O2 uptake) of the chemical 1-phenylethan-1-ol by test microorganisms was determined to be 75 µl. Thus, based on this, chemical 1-phenylethan-1-ol was considered to be not readily biodegradable in nature.

 

Although one study from peer reviewed journal indicates that the chemical 1-phenylethan-1-ol is not readily biodegradable as it may be because in this experiment duration for degradation was very less i.e., 210 minutes, but based on the other studies overall results for target chemical 1-phenylethan-1-ol (from peer reviewed journals, authoritative databases HSDB, PubChem and secondary source), it can be concluded that the test substance 1-phenylethan-1-ol is considered to be readily biodegradable in nature.