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Environmental fate & pathways

Biodegradation in water: screening tests

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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:
other: Data is from peer reviewed journal
Justification for type of information:
Data is from peer reviewed journal
Qualifier:
according to
Guideline:
other: as mentioned below
Principles of method if other than guideline:
Biodegradation study was conducted for 24 hrs for evaluating the percentage biodegradability of test substance (2-methoxyphenyl)methanol using Nocardia corallina B-276 ATCC 31338.
GLP compliance:
not specified
Specific details on test material used for the study:
- Name (IUPAC name): (2-methoxyphenyl)methanol
- Common name: 2-Methoxybenzyl alcohol
- Molecular formula: C8H10O2
- Molecular weight: 136.165 mg/l
- Smiles:O(c1c(cccc1)CO)C
- InChI:1S/C8H10O2/c1-10-8-5-3-2-4-7(8)6-9/h2-5,9H,6H2,1H3
- Substance type:Organic
- Physical state: Liquid
- Other: Test substrate was prepared by conventional methods mentioned in the literature or purchased from Aldrich, Sigma or Janssen.
Oxygen conditions:
not specified
Inoculum or test system:
other: Nocardia corallina B-276 ATCC 31338
Details on inoculum:
- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure): Test inoculum was for the study was Nocardia corallina B-276 ATCC 31338.
- Method of cultivation: Nocardia corallina B-276 ATCC 31338 was grown at 28–30°C on agar plates. Incubation of liquid cultures was done in an orbital shaker.

- Preparation of inoculum for exposure: Test inoculum was prepared in two procedures-
Preculture I
A 125 ml Erlenmeyer flask containing 50 ml of sterile culture medium was inoculated from an agar plate (three days old) and incubated at 28–30 °C on an orbital shaker (200 rpm) for 20–24 h.

Preculture II
The content of Preculture I flask was aseptically poured into a 250 ml Erlenmeyer flask containing 100 ml of fresh sterile culture medium. The flask was incubated at 28–30 °C on an orbital shaker (200 rpm) for 24 h.
Duration of test (contact time):
24 h
Initial conc.:
138.165 mg/L
Based on:
test mat.
Remarks:
(1mM)
Parameter followed for biodegradation estimation:
other: TLC
Details on study design:
TEST CONDITIONS
- Test temperature: 28-30°C

TEST SYSTEM
- Culturing apparatus: Erlenmeyer flask was used as a test vessel for the study.
Key result
Parameter:
other: TLC
Value:
5
Sampling time:
24 h
Remarks on result:
other: %Yield = 5%
Details on results:
Test substance undergoes 5% degradation by TLC parameter in 24 hrs.

Table: %Yield of test chemical (2-methoxyphenyl)methanol.

 

Test chemical R grp

%Yield (M/M)

Reaction time (h)

R = OCH3

5

27

Validity criteria fulfilled:
not specified
Interpretation of results:
not readily biodegradable
Conclusions:
The percentage degradation of test substance (2-methoxyphenyl)methanol was determined to be 5% by TLC parameter in 24 hrs. Thus, based on percentage degradation, (2-methoxyphenyl)methanol is considered to be not readily biodegradable in water.
Executive summary:

Biodegradation study was conducted for 24 hrs at a temperature range of 28-30°C for evaluating the percentage biodegradability of test substance (2-methoxyphenyl)methanol (CAS no. 612-16-8)using Nocardia corallina B-276 ATCC 31338. Nocardia corallina B-276 ATCC 31338 was grown at 28–30°C on agar plates. Incubation of liquid cultures was done in an orbital shaker.Test inoculum was prepared in two procedures. InPreculture I -A 125 ml Erlenmeyer flask containing 50 ml of sterile culture medium was inoculated from an agar plate (three days old) and incubated at 28–30 °C on an orbital shaker (200 rpm) for 20–24 h and inPreculture II -The content of Preculture I flask was aseptically poured into a 250 ml Erlenmeyer flask containing 100 ml of fresh sterile culture medium. The flask was incubated at 28–30 °C on an orbital shaker (200 rpm) for 24 h.Erlenmeyer flask was used as a test vessel for the study.Under aseptic conditions the substrate (1 mmol – 138.165 mg/l) was added to the flask containing Preculture II using 1 ml of N,N-Dimethylformamide, followed by the addition ofn-octane (15 ml). The mixture (166 ml final volume) was incubated at 28–30 °C on an orbital shaker (200 rpm). The biotransformation was monitored by TLC, and stopped by acidifing to pH 1 with 0.05 M HCl, then saturated with NaCl and filtered through Celite; the carboxylic acids were extracted with ethyl acetate or dichloromethane (4X25 ml). The acids were purified by recrystallization.The percentage degradation of test substance(2-methoxyphenyl)methanol was determined to be 5% by TLC parameter in 24 hrs. Thus, based on percentage degradation, (2 -methoxyphenyl)methanol is considered to be not readily biodegradable in nature.

Description of key information

Biodegradation study was conducted for 24 hrs at a temperature range of 28-30°C for evaluating the percentage biodegradability of test substance (2-methoxyphenyl)methanol (CAS no. 612-16-8) using Nocardia corallina B-276 ATCC 31338 (Herminia I. Perez et. al; 1998). Nocardia corallina B-276 ATCC 31338 was grown at 28–30°C on agar plates. Incubation of liquid cultures was done in an orbital shaker.Test inoculum was prepared in two procedures. InPreculture I -A 125 ml Erlenmeyer flask containing 50 ml of sterile culture medium was inoculated from an agar plate (three days old) and incubated at 28–30 °C on an orbital shaker (200 rpm) for 20–24 h and inPreculture II -The content of Preculture I flask was aseptically poured into a 250 ml Erlenmeyer flask containing 100 ml of fresh sterile culture medium. The flask was incubated at 28–30 °C on an orbital shaker (200 rpm) for 24 h.Erlenmeyer flask was used as a test vessel for the study.Under aseptic conditions the substrate (1 mmol – 138.165 mg/l) was added to the flask containing Preculture II using 1 ml of N,N-Dimethylformamide, followed by the addition ofn-octane (15 ml). The mixture (166 ml final volume) was incubated at 28–30 °C on an orbital shaker (200 rpm). The biotransformation was monitored by TLC, and stopped by acidifing to pH 1 with 0.05 M HCl, then saturated with NaCl and filtered through Celite; the carboxylic acids were extracted with ethyl acetate or dichloromethane (4X25 ml). The acids were purified by recrystallization.The percentage degradation of test substance(2-methoxyphenyl)methanol was determined to be 5% by TLC parameter in 24 hrs. Thus, based on percentage degradation, (2 -methoxyphenyl)methanol is considered to be not readily biodegradable in nature.

Key value for chemical safety assessment

Biodegradation in water:
under test conditions no biodegradation observed

Additional information

Experimental study for the target compound (2-methoxyphenyl)methanol (CAS No. 612-16-8) and supporting study 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 (Herminia I. Perez et. al; 1998), biodegradation experiment was conducted for 24 hrs at a temperature range of 28-30°C for evaluating the percentage biodegradability of test substance (2-methoxyphenyl)methanol (CAS no. 612-16-8) using Nocardia corallina B-276 ATCC 31338. Nocardia corallina B-276 ATCC 31338 was grown at 28–30°C on agar plates. Incubation of liquid cultures was done in an orbital shaker.Test inoculum was prepared in two procedures. InPreculture I -A 125 ml Erlenmeyer flask containing 50 ml of sterile culture medium was inoculated from an agar plate (three days old) and incubated at 28–30 °C on an orbital shaker (200 rpm) for 20–24 h and inPreculture II -The content of Preculture I flask was aseptically poured into a 250 ml Erlenmeyer flask containing 100 ml of fresh sterile culture medium. The flask was incubated at 28–30 °C on an orbital shaker (200 rpm) for 24 h.Erlenmeyer flask was used as a test vessel for the study.Under aseptic conditions the substrate (1 mmol – 138.165 mg/l) was added to the flask containing Preculture II using 1 ml of N,N-Dimethylformamide, followed by the addition ofn-octane (15 ml). The mixture (166 ml final volume) was incubated at 28–30 °C on an orbital shaker (200 rpm). The biotransformation was monitored by TLC, and stopped by acidifing to pH 1 with 0.05 M HCl, then saturated with NaCl and filtered through Celite; the carboxylic acids were extracted with ethyl acetate or dichloromethane (4X25 ml). The acids were purified by recrystallization.The percentage degradation of test substance (2-methoxyphenyl)methanol was determined to be 5% by TLC parameter in 24 hrs. Thus, based on percentage degradation, (2 -methoxyphenyl)methanol is considered to be not readily biodegradable in nature.

 

In a supporting study from peer reviewed journal (Edward L. Fincher and W. J. Payne, 1962) for the read across chemical 1-hydroxy-2-phenoxyethane (CAS no. 122-99-6),biodegradation experiment was conducted for evaluating the percentage biodegradability of read across substance 1 -hydroxy-2 -phenoxyethane (CAS no. 122 -99 -6) by using soil bacterium. The test bacterium was isolated from soil enriched for several days with aqueous solutions of triethylene glycol. The enriched soil was suspended in water and permitted to settle. Afterwards, loops dipped in the supernatant were streaked over minimal salts agar containing 0.25% triethylene glycol. Colonies appearing on plates incubated at 30°C for 5 to 7 days were picked and streaked for pure culture isolation. The bacterium was kept in stock culture on nutrient agar or Trypticase Glucose Extract Agar slants and stored at 4°C. For experimental studies, the organism was cultured on a basal salts medium (pH 7.4) containing K2HPO4, 9.28 g; KH2PO4, 1,81 g; NH4Cl, 0.5 g; (NH4)2SO4, 0.5 g; Na%S04, 0.5 g; and 0.1 g of MgSO4 7H20 per liter of distilled water with additions in the form of various glycols and ether alcohols as sole carbon and energy sources. In certain experiments, minimal quantities of yeast extract were added. Growth on the various media was determined turbidimetrically with a model-6A Coleman Junior spectrophotometer, at 420 m,u for colorless media and 660 m,u for yellow-tinted media. The bacteria were cultured with continuous shaking at 30°C in 30-ml lots of appropriate media in 125-ml flasks with cuvettes attached for convenience of assay. Cell-mass production on various media was determined by harvesting cells on tared Millipore filter pads, washing with distilled water, drying at 80°C overnight, and weighing. Cells to be assayed for oxidative activity were cultured at 30°C on a shaker for 72 to 96 hr in 0.04 M glycol-basal salts medium. The bacteria were harvested by centrifugation, washed twice in basal salts medium without glycol, and resuspended in the basal medium. The oxygen uptake of the suspensions incubated at 30°C with the test chemical1-hydroxy-2-phenoxyethanewas determined by standard manometric techniques.As test bacterium did not utilize the chemical 1-hydroxy-2-phenoxyethane for growth, the substance 1-hydroxy-2-phenoxyethane was considered to undergoes 0% degradation by O2 uptake parameter. Thus, based on percentage degradation, 1-hydroxy-2-phenoxyethane is considered to be not readily biodegradable in nature.

 

On the basis of above results for target chemical (2 -methoxyphenyl)methanol (from peer reviewed journal) and for its read across substance (from peer reviewed journal), it can be concluded that the test substance (2 -methoxyphenyl)methanol can be expected to be not readily biodegradable in nature.