4-methoxybenzyl alcohol

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:

other: Data is from peer reviewed journal

Justification for type of information:

Data is from peer reviewed journal

Qualifier:

according to guideline

Guideline:

other: as mentioned below

Principles of method if other than guideline:

Biodegradation study was conducted for 14 days for evaluating the percentage biodegradability of test chemical.

GLP compliance:

not specified

Oxygen conditions:

aerobic

Inoculum or test system:

other: Bacteria (strain GM-14)

Details on inoculum:

- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure): Test inoculum Bacteria (strain GM-14) was isolated from soil from a rice field in Krasnodar Territory, Russia utilizing chlorobenzene as the sole source of carbon and energy.
- Other (Isolation of test bacteria): Chlorobenzene (10 ml) and 2 g of soil were added directly to a 250-ml flask with 50 ml of KSN medium and incubated while stationary at 288C. After disappearance of the substrate (2 weeks), more chlorobenzene was added. After 2 months, 20 ml of this enrichment culture, 80 ml of KSN medium, and 20 ml of chlorobenzene were incubated in a conical flask (500 ml) on a gyratory shaker at 180 rpm until turbid (7 days), diluted 1:10 (vol/vol) with KSN medium containing chlorobenzene (20 ml/100 ml), and incubated until visibly turbid. This procedure was repeated five times, the mixture was plated on KSN agar, chlorobenzene was injected between the dish bottom and the agar layer (20 ml of chlorobenzene per plate), and the mixture was incubated under air in a desiccator at 28°C. Colonies grown on the plates were streaked pure by serial dilutions of single colonies on KSN agar with chlorobenzene.

Duration of test (contact time):

14 d

Initial conc.:

30 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

test mat. analysis

Details on study design:

TEST CONDITIONS
- Composition of medium: KSN medium was used as a test medium for the study. The composition of the chloride-free minimal salts KSN medium used for the enrichment and cultivation was as follows (grams per liter of distilled water): K2HPO4. 3H2O, 4.0; NaH2PO4.2H2O, 1.0; (NH4)2SO4, 0.5; MgSO4.7H2O, 0.15; Ca(NO3)2.4H2O, 0.01 (pH 7.0 to 7.3).
- Additional substrate: The aromatic substrates were added to the autoclaved (1218C) KSN medium.
- Test temperature: 22°C

TEST SYSTEM
- Culturing apparatus: Flasks of 500 ml was used as a test vessel for the study.

Remarks on result:

other: Test chemical was utilized as a sole source of carbon by the test bacteria strain GM-14.

Validity criteria fulfilled:

not specified

Interpretation of results:

other: biodegradable

Conclusions:

The test chemical was utilized as a sole source of carbon by the test bacteria strain GM-14. Thus, based on this, test chemical is considered to be biodegradable in water.

Executive summary:

Biodegradation study was conducted for 14 days for evaluating the percentage biodegradability of test chemical. Bacteria (strain GM-14) was used as a test inoculum isolated from soil from a rice field in Krasnodar Territory, Russia utilizing chlorobenzene as the sole source of carbon and energy. Flasks of 500 ml was used as a test vessel for the study. KSN medium was used as a test medium for the study. The composition of the chloride-free minimal salts KSN medium used for the enrichment and cultivation was as follows (grams per liter of distilled water): K2HPO4.3H2O, 4.0; NaH2PO4.2H2O, 1.0; (NH4)2SO4, 0.5; MgSO4.7H2O, 0.15; Ca(NO3)2.4H2O, 0.01 (pH 7.0 to 7.3). The aromatic substrates were added to the autoclaved (1218C) KSN medium. Utilization of test chemical by strain GM-14 was examined on a gyratory shaker at 22°C in 500-ml flasks with 180 ml of KSN medium and with 20 ml of inoculum grown on CB plus 4-chlorophenol (4-CP) to an initial A540 of 0.015. Each compound (30 mg/liter) was added as the sole carbon source, and the addition was repeated after 7 days.Growth rates were recorded from the exponential phase of growth.The test chemical was utilized as a sole source of carbon by the test bacteria strain GM-14. Thus, based on this, test chemical is considered to bebiodegradable in water. 

Description of key information

Biodegradation study was conducted for 14 days for evaluating the percentage biodegradability of test chemical (GENNADI M. ZAITSEV et. al., 1995). Bacteria (strain GM-14) was used as a test inoculum isolated from soil from a rice field in Krasnodar Territory, Russia utilizing chlorobenzene as the sole source of carbon and energy. Flasks of 500 ml was used as a test vessel for the study. KSN medium was used as a test medium for the study. The composition of the chloride-free minimal salts KSN medium used for the enrichment and cultivation was as follows (grams per liter of distilled water): K2HPO4.3H2O, 4.0; NaH2PO4.2H2O, 1.0; (NH4)2SO4, 0.5; MgSO4.7H2O, 0.15; Ca(NO3)2.4H2O, 0.01 (pH 7.0 to 7.3). The aromatic substrates were added to the autoclaved (1218C) KSN medium. Utilization of test chemical by strain GM-14 was examined on a gyratory shaker at 22°C in 500-ml flasks with 180 ml of KSN medium and with 20 ml of inoculum grown on CB plus 4-chlorophenol (4-CP) to an initialA540 of 0.015. Each compound (30 mg/liter) was added as the sole carbon source, and the addition was repeated after 7 days.Growth rates were recorded from the exponential phase of growth.The test chemical was utilized as a sole source of carbon by the test bacteria strain GM-14. Thus, based on this, test chemical is considered to bebiodegradable in water. 

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Additional information

Experimental study and predicted data for the test chemical and supporting study for its structurally similar read across chemical were reviewed for the biodegradation end point which are summarized as below:

 

In an experimental key study from peer reviewed journal (GENNADI M. ZAITSEV et. al., 1995), biodegradation experiment was conducted for 14 days for evaluating the percentage biodegradability of test chemical. Bacteria (strain GM-14) was used as a test inoculum isolated from soil from a rice field in Krasnodar Territory, Russia utilizing chlorobenzene as the sole source of carbon and energy. Flasks of 500 ml was used as a test vessel for the study. KSN medium was used as a test medium for the study. The composition of the chloride-free minimal salts KSN medium used for the enrichment and cultivation was as follows (grams per liter of distilled water): K2HPO4.3H2O, 4.0; NaH2PO4.2H2O, 1.0; (NH4)2SO4, 0.5; MgSO4.7H2O, 0.15; Ca(NO3)2.4H2O, 0.01 (pH 7.0 to 7.3). The aromatic substrates were added to the autoclaved (1218C) KSN medium. Utilization of test chemical by strain GM-14 was examined on a gyratory shaker at 22°C in 500-ml flasks with 180 ml of KSN medium and with 20 ml of inoculum grown on CB plus 4-chlorophenol (4-CP) to an initial A540 of 0.015. Each compound (30 mg/liter) was added as the sole carbon source, and the addition was repeated after 7 days. Growth rates were recorded from the exponential phase of growth. The test chemical was utilized as a sole source of carbon by the test bacteria strain GM-14. Thus, based on this, test chemical is considered to be biodegradable in water. 

 

In a prediction done using the Estimation Programs Interface Suite (2018), the biodegradation potential of the test chemical 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 test chemical is expected to be readily biodegradable.

 

For the test chemical, 28-days Closed Bottle test following the OECD guideline 301 D to determine the ready biodegradability of the test chemical (Experimental study report, 2017). The study was performed at a temperature of 20°C. The test system included control, test item and reference item. Domestic waste water, surface soil and soil samples from polluted sites receiving predominantly domestic waste was collected and were mixed to get diluted suspension. The inoculum was kept aerobic until being used for experiment by supplying organic and inorganic sources required by micro flora to sustain at controlled laboratory conditions. This gave the bacterial count as 107 to 108 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 32ml/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 74.69 %. Degradation of Sodium Benzoate exceeds 39.15 % after 7 days & 52.40 % after 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 1.2 mgO2/mg. ThOD was calculated as 1.926 mgO2/mg. Accordingly, the % degradation of the test item after 28 days of incubation at 20 ± 1°C according to Closed Bottle test was determined to be 62.5%. Based on the results, the test item, under the test conditions, was considered to be readily biodegradable in nature.

 

On the basis of above results of the test chemical, it can be concluded that the test chemical can be considered to be readily biodegradable in nature.