Benzyl isobutyrate

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

data from handbook or collection of data

Remarks:

for read across

Justification for type of information:

Data for the target chemical is summarized based on the structurally similar read across chemicals

Reason / purpose for cross-reference:

read-across source

Reason / purpose for cross-reference:

read-across source

Reason / purpose for cross-reference:

read-across source

Qualifier:

according to guideline

Guideline:

other: refer principle below

Principles of method if other than guideline:

Biodegradation of test chemical was estimated by applying weight of evidence approach using experimental data from structurally and functionally similar read across chemicals.

GLP compliance:

not specified

Oxygen conditions:

aerobic

Inoculum or test system:

other: sludge

Details on inoculum:

1. Fresh activated sludge from a biological waste water treatment plant treating predominantly domestic sewage (City og Geneva, Aire) was used.
The sludge is collected in the morning, washed three times in the mineral medium (by centrifuging at 1000g for 10 min, discarding the supernatant and resuspending in the mineral medium) and kept aerobic until being used on the same day.
Determination of the dry weight of suspended solids
The dry weight of suspended solids is determined by taking two 50 ml samples of the homogenized sludge, evaporating water on a steam bath, drying in an oven at 105-110°C for two hours and weighing the residue

2. concentration of activated sludge is 30 mg.L

3. 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.

Duration of test (contact time):

28 d

Initial conc.:

100 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

O2 consumption

Remarks:

BOD

Parameter followed for biodegradation estimation:

TOC removal

Parameter followed for biodegradation estimation:

test mat. analysis

Remarks:

GC

Details on study design:

1. Preparation of the flasks:
Test substance samples (25 mg, corresponding to 100 mg/L in a 250 ml flask) are weighed in small aluminium boats and added directly to the test flasks of the SAPROMAT, whereas reference substance samples (sodium benzoate) are added as 0.1ml of a 25 mg/ml solution in mineral medium.
All flasks are filled with 250ml of mineral medium. Samples of test or reference substance, or both, are added. Then, a volume of suspended sludge corresponding to 7.5 mg dry weight (generally 1 to 3 ml) is added. Except when the test substance has an acid or alkaline character, the pH of each flask is not measured but assumed to be the same as the mineral medium, in order not to remove any floating undissolved test substance from the test medium by dipping the glass electrode in it. Neutral test substances, even sodium benzoate, were shown not to affect the pH of the medium by more than 0.1 pH unit. About 2g of soda lime is placed in an attachment of the stopper, the flasks are closed and placed in the water bath of the SAPROMAT. After temperature and pressure equilibration, the oxygen meters of the instrument are set to zero (time zero of the experiment).

2. Standard type

3. The test system included control, test item and reference item. The concentration of test and reference item (Sodium Benzoate) chosen for the study was 100 mg/L, while that of inoculum was 10ml/l. ThOD (Theoretical oxygen demand) of test and reference item were determined by calculation. % Degradation was calculated using the values of BOD and ThOD for test item and reference item.

Parameter:

% degradation (O2 consumption)

Value:

89

Sampling time:

29 d

Remarks on result:

other: other details not available

Parameter:

other: BOD

Value:

95

Sampling time:

28 d

Remarks on result:

other: other details not available

Parameter:

% degradation (TOC removal)

Value:

98

Sampling time:

28 d

Remarks on result:

other: other deatils not available

Parameter:

% degradation (test mat. analysis)

Remarks:

GC

Value:

100

Sampling time:

28 d

Remarks on result:

other: other details not available

Parameter:

% degradation (O2 consumption)

Value:

81.15

Sampling time:

28 d

Remarks on result:

other: other deatils not available

1. Theoretical Oxygen demand

Molecular formula: C10H12O2

Molecular weight: 164.20 g/mol

Theoretical Oxygen demand (ThOD): 2.34 mgO2/mg

 

Biodegradability

Biological Oxygen Demand (BOD, mg O2/L, adjusted to nominal concentrations):

		Days	2	7	12	21	28	29
BOD Sludge	1^stflask	B1	5.0	12.0	14.0	18.0	21.0	21.0
	2^ndflask	B2	7.0	13.0	15.0	18.0	21.0	21.0
	Mean	B	6.0	12.0	14.0	18.0	21.0	21.0
BOD Test substance	1^stflask	C1	58.2	145.3	191.8	218.9	226.8	226.8
	2^ndflask	C2	60.3	173.8	191.3	218.6	229.3	231.3
	1^stflask corrected	C1-B	52.2	132.8	177.3	200.9	205.8	205.8
	2^ndflask corrected	C2-B	54.3	161.3	176.8	200.6	208.3	210.3
% degradation	1^stflask	D1	22	57	76	86	88	88
	2^ndflask	D2	23	69	76	86	89	90
	Mean	D	23	63	76	86	88	89

B= (B1+B2)/2

D1= 100*(C1-B)/ThOD*[S]

D2= 100*(C2-B)/ThOD*[S]

D= (D1+D2)/2

[S]: initial test substance concentration (mg/L)

2. no additional information

3. The apparatus used in this study is Respirometer BOD Sensor System (Code: F102B0133;non-automatic pressure measurement sensor system)and Respirometric incubator (FOC 120i)) by VELP Scientifica.

Test System		Mineral media	Concentration of Benzyl butyrate (mg/l)	Concentration of Sodium Benzoate (mg/l)	Concentration of Inoculum (ml/l)
1.   Inoculum Blank (Control)	B1	√	-	-	10 ml
	B2	√	-	-	10 ml
2.   Test Suspension	B1	√	100	-	10 ml
	B2	√	100	-	10 ml
3.   Procedure Control (Reference Item)	B1	√	-	100	10 ml
	B2	√	-	100	10 ml

Validity criteria fulfilled:

not specified

Interpretation of results:

readily biodegradable

Conclusions:

By applying weight of evidence approach and considering results of experimental data from structurally and functionally similar read across chemicals which are mentioned above the biodegradation of test chemical was determined to be >80% in 28 days. On the basis of percent degradation it is concluded that test chemical is readily biodegradable.

Executive summary:

Biodegradation of test chemical was estimated by applying weight of evidence approach using experimental data from structurally and functionally similar read across chemicals. The studies are as mentioned below:

In first experimental study the Ready biodegradability of test chemical was determined by the Manometric Respirometry test according to the OECD Guidelines No. 301 F. Fresh activated sludge from a biological waste water treatment plant treating predominantly domestic sewage (City og Geneva, Aire) was used. The sludge is collected in the morning, washed three times in the mineral medium (by centrifuging at 1000g for 10 min, discarding the supernatant and resuspending in the mineral medium) and kept aerobic until being used on the same day. The dry weight of suspended solids is determined by taking two 50 ml samples of the homogenized sludge, evaporating water on a steam bath, drying in an oven at 105-110°C for two hours and weighing the residue. In the study, a measured volume of the inoculated mineral medium, containing a known concentration of the test substance (100 mg/L) as the nominal sole source of organic carbon, is stirred in a closed flask at a constant temperature (22±1°C) for upto 28 days. The consumption of oxygen is determined by measuring the quantity of oxygen (produced electrolytically) required to maintain constant the gas volume in the respirometer flask. The respirometer used during this study is a SAPROMAT D 12. Sodium benzoate was used as a reference substance for the study. Test chemical undergoes 89% biodegradation after 29 days (88% after 28 days) in the test conditions. Biodegradation starts on day 2 and reaches 76% at the end of the 10 day window (days 2 to 12). Thus, test chemical was considered to be readily biodegradable according to this test.

Another experimental study was reviewed from the authoritative database (J check) in this study the biodegradation screening test was conducted for 28 days (4 weeks) for evaluating the percentage biodegradability of the test substance. Concentration of inoculum i.e, sludge is 30 mg/l and initial test substance conc. used in the study was 100 mg/l. The percentage degradation of test substance was determined to be 95% by BOD, 98% by TOC and 100% by GC. Thus, the substance was considered to be readily biodegradable in water.

In last experimental study, 28-days Manometric respirometry test following the OECD guideline 301F was performed to determine the ready biodegradability of the test chemical. % Degradation was calculated using the values of BOD and ThOD for test item and reference item. The BOD28value of test chemical was observed to be 1.967 mgO2/mg. ThOD was calculated as 2.424 mgO2/mg. Accordingly, the % degradation of the test item after 28 days of incubation at 20 ± 1°C according to manometric respirometry test was determined to be 81.15%.Based on the results, the test item, under the test conditions, was determined to be readily-Biodegradable at 20 ± 1°C over a period of 28 days.

By applying weight of evidence approach and considering results of experimental data from structurally and functionally similar read across chemicals which are mentioned above the biodegradation of test chemical was determined to be >80% in 28 days. On the basis of percent degradation it is concluded that test chemical is readily biodegradable.

Description of key information

By applying weight of evidence approach and considering results of experimental data from structurally and functionally similar read across chemicals which are mentioned above the biodegradation of test chemical was determined to be >80% in 28 days. On the basis of percent degradation it is concluded that test chemical is readily biodegradable.

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Additional information

Biodegradation of test chemical was estimated by applying weight of evidence approach using experimental data from structurally and functionally similar read across chemicals. The studies are as mentioned below:

In first experimental study the Ready biodegradability of test chemical was determined by the Manometric Respirometry test according to the OECD Guidelines No. 301 F. Fresh activated sludge from a biological waste water treatment plant treating predominantly domestic sewage (City og Geneva, Aire) was used. The sludge is collected in the morning, washed three times in the mineral medium (by centrifuging at 1000g for 10 min, discarding the supernatant and resuspending in the mineral medium) and kept aerobic until being used on the same day. The dry weight of suspended solids is determined by taking two 50 ml samples of the homogenized sludge, evaporating water on a steam bath, drying in an oven at 105-110°C for two hours and weighing the residue. In the study, a measured volume of the inoculated mineral medium, containing a known concentration of the test substance (100 mg/L) as the nominal sole source of organic carbon, is stirred in a closed flask at a constant temperature (22±1°C) for upto 28 days. The consumption of oxygen is determined by measuring the quantity of oxygen (produced electrolytically) required to maintain constant the gas volume in the respirometer flask. The respirometer used during this study is a SAPROMAT D 12. Sodium benzoate was used as a reference substance for the study. Test chemical undergoes 89% biodegradation after 29 days (88% after 28 days) in the test conditions. Biodegradation starts on day 2 and reaches 76% at the end of the 10 day window (days 2 to 12). Thus, test chemical was considered to be readily biodegradable according to this test.

Another experimental study was reviewed from the authoritative database (J check) in this study the biodegradation screening test was conducted for 28 days (4 weeks) for evaluating the percentage biodegradability of the test substance. Concentration of inoculum i.e, sludge is 30 mg/l and initial test substance conc. used in the study was 100 mg/l. The percentage degradation of test substance was determined to be 95% by BOD, 98% by TOC and 100% by GC. Thus, the substance was considered to be readily biodegradable in water.

In last experimental study, 28-days Manometric respirometry test following the OECD guideline 301F was performed to determine the ready biodegradability of the test chemical. % Degradation was calculated using the values of BOD and ThOD for test item and reference item. The BOD28value of test chemical was observed to be 1.967 mgO2/mg. ThOD was calculated as 2.424 mgO2/mg. Accordingly, the % degradation of the test item after 28 days of incubation at 20 ± 1°C according to manometric respirometry test was determined to be 81.15%.Based on the results, the test item, under the test conditions, was determined to be readily-Biodegradable at 20 ± 1°C over a period of 28 days.

By applying weight of evidence approach and considering results of experimental data from structurally and functionally similar read across chemicals which are mentioned above the biodegradation of test chemical was determined to be >80% in 28 days. On the basis of percent degradation it is concluded that test chemical is readily biodegradable.