Cinnamaldehyde

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:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study

Justification for type of information:

Experimental result using OECD guidelines.

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 D (Ready Biodegradability: Closed Bottle Test)

GLP compliance:

no

Oxygen conditions:

aerobic

Inoculum or test system:

other: Mixed inoculum

Details on inoculum:

- Source of inoculum/activated sludge: Polyseed capsule (mixed culture) was used as a test inoculum for this study. Test inoculum polyseed capsule was made up of blend of specialized microbial cultures and food grade gelatin made by International Laboratory Supply (InterLab), LTD.
- Preparation of inoculum for exposure: 1 polyseed capsule was 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.
- Pretreatment / Preconditioning: No preconditioning was given to the test inoculum as the polyseed capsule requires only one hour of stirring to activate it.
- Concentration of sludge: 1 Polyseed capsule was added in 500 mL DI water and then stirred for 1 hour for proper mixing and functioning of inoculum & settled for 15 minutes to eliminate the bran. Decanted polyseed solution was used as mixed inoculum. From this, 32 ml/l concentration was taken for test substance, control blank and reference. For 125 ml BOD bottle, 4 ml was used.

Duration of test (contact time):

28 d

Initial conc.:

4 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

TEST CONDITIONS
- Composition of medium: OECD mineral medium was used for the study
- Test temperature: 20°C
- Continuous darkness: Yes
- Other: The water used in this study is deionized water.

TEST SYSTEM
- Culturing apparatus: The apparatus used in this study is BOD bottles; with glass stoppers (125 ml), BOD incubator & oxygen electrode and meter.

CONTROL AND BLANK SYSTEM
- Inoculum blank: it contains only test inoculum
- Procedure control: contains reference compound and inoculum

Reference substance:

benzoic acid, sodium salt

Key result

Parameter:

% degradation (O2 consumption)

Value:

61.02

Sampling time:

14 d

Remarks on result:

other: Other details not known

Details on results:

The oxygen consumed by the test systems was corrected for oxygen consumption occurring in the blank test systems. The BOD Values (mgO2/mg) and percent biodegradation results for each test system are reported in Tables 2 and 3, respectively. The BOD14 value of test chemical was observed to be 1.525 mgO2/mg. ThOD was determined by calculation as 2.54 mgO2/mg. % degradation was calculated using the values of BOD and ThOD for test item and was determined to be 61.02 % at 20 ± 1°C. The % degradation of procedure control (reference item) was also calculated using BOD & ThOD and was determined to be 61.44 %. Degradation of Sodium Benzoate exceeds 39.15 % on 7 days & 61.44 % on 14th day. The activity of the inoculum is thus verified and the test can be considered as valid.

Results with reference substance:

The % degradation of procedure control (reference item) was also calculated using BOD & ThOD and was determined to be 61.44 %. Degradation of Sodium Benzoate exceeds 39.15 % on 7 days & 61.44 % on 14th day. The activity of the inoculum is thus verified and the test can be considered as valid.

TABLE 1: D.O Values (mg/L) 

No. of Days	Inoculum Blank (Control)	Test Suspension	Procedure Control (Reference Item)	Toxicity control
0	7.4	7.4	6.9	7.8
3	7	4	4.6	5.16
7	6.8	3.5	3.7	4.32
10	6.5	2.9	2.5	3.06
14	6.4	0.2	1.8	2.72
21	6.2	0.3	1.2	1.52
28	6	0.2	0.6	0.6

TABLE 2: BOD Values (mg O2/mg)

 

No. of Days	Test Suspension	Procedure Control (Reference Item)	Toxicity control
0	0	0	0
3	0.75	0.47	0.56
7	0.82	0.65	0.72
10	0.9	0.87	0.96
14	1.55	1.02	1.02
21	1.47	1.12	1.27
28	1.45	1.22	1.45

 

TABLE 3: PERCENT BIODEGRDATION RESULTS

No. of Days	Test Suspension	Procedure Control (Reference Item)	Toxicity control
0	0%	0%	0%
3	29.52%	28.31%	22.04%
7	32.28%	39.15%	28.34%
10	35.43%	52.4%	37.79%
14	61.02%	61.44%	40.15%
21	57.87%	67.46%	50.00%
28	57.08%	73.49%	57.08%

 

Table 4: BOD14, THOD AND % BIODEGRADATION VALUES

 

Method details	BOD14 (mgO2/mg)	ThOD (mgO2/mg)	%Biodegradation
Test Item	1.55	2.54	61.02
Reference Item	1.02	1.66	61.44
Toxicity control	1.02	1.45	70.34

Validity criteria fulfilled:

yes

Remarks:

All the validity criteria as per OECD 301D are met

Interpretation of results:

readily biodegradable

Conclusions:

The test chemical undergoes 61.02% and 57.08% biodegradation after 14 & 28 days in the test condition. Overall, the test chemical was considered to be readily biodegradable in nature.

Executive summary:

Biodegradation study was conducted for 28-days following the OECD guideline 301 D for determining the ready biodegradability of the test chemical. The study was performed at a temperature of 20°C under aerobic conditions. Aerobic conditions was provided by means of mineral media which is aerated for 20 hours prior to start of the experiment. The test system included control, test chemical, reference substance and toxicity control. Polyseed capsule (mixed culture) was used as a test inoculum for the study. Test inoculum polyseed capsule was composed of blend of specialized microbial cultures and food grade gelatin made by International Laboratory Supply (InterLab), LTD. No pretreatment / preconditioning was given to the test inoculum as the polyseed capsule requires only one hour of stirring to activate it. 1 Polyseed capsule was added in 500 mL DI water and then stirred for 1 hour for proper mixing and functioning of inoculum & settled for 15 minutes to eliminate the bran. Decanted polyseed solution was used as mixed inoculum. Thus, concentration of test inoculum used for the study was 32 ml/l which corresponds to 10E7 to 10E8 CFU/ml. The concentration of test and reference substance (Sodium Benzoate) chosen for both the study was 4 mg/L. OECD mineral medium was used for the study. ThOD (Theoretical oxygen demand) of test and reference chemical was determined by calculation. % degradation was calculated using the values of BOD and ThOD for test chemical and reference substance. The % degradation of procedure control (reference item) was also calculated using BOD & ThOD and was determined to be 61.44%. Degradation of Sodium Benzoate exceeds 39.15% on 7 days & 61.44% on 14th day. The activity of the inoculum is thus verified and the test can be considered as valid. The BOD14 value of test chemical was observed to be 1.525 mgO2/mg. ThOD was calculated as 2.54 mgO2/mg. Accordingly, the % degradation of the test chemical after 14 and 28 days of incubation at 20 ± 1°C according to Closed Bottle test was determined to be 61.02% & 57.08%. Overall, the test chemical under the test conditions, was considered to be readily biodegradable in nature.

Description of key information

Biodegradation study was conducted for 28 days for evaluating the percentage biodegradability of test chemical. The study was performed by a modified OECD screening test conducted as per the method similar to OECD Guideline 301 B (Ready biodegradability: CO2 evolution). Secondary effluent from a sewage treatment plant was usedas a test inoculum. A test chemical solution was inoculated with the test inoculum in a mineral medium in test flasks and incubated further for a period of 28 days. The percentage degradation of test chemical was determined to be 89%, 94% and 100% by using DOC removal parameter after a period of 7, 14 and 21 days. Thus, based on percentage degradation, test chemical was considered to be readily biodegradable in water.

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Additional information

Various experimental studies of the target chemical were reviewed for the biodegradation end point which are summarized as below:

Biodegradation study was conducted for 28 days for evaluating the percentage biodegradability of test chemical. The study was performed by a modified OECD screening test conducted as per the method similar to OECD Guideline 301 B (Ready biodegradability: CO2 evolution). Secondary effluent from a sewage treatment plant was usedas a test inoculum. A test chemical solution was inoculated with the test inoculum in a mineral medium in test flasks and incubated further for a period of 28 days. The percentage degradation of test chemical was determined to be 89%, 94% and 100% by using DOC removal parameter after a period of 7, 14 and 21 days. Thus, based on percentage degradation, test chemical was considered to be readily biodegradable in water.

In an experimental study from study report (2018),biodegradation experiment was conducted for 28-days following the OECD guideline 301 D for determining the ready biodegradability of the test chemical. The study was performed at a temperature of 20°C under aerobic conditions. Aerobic conditions was provided by means of mineral media which is aerated for 20 hours prior to start of the experiment. The test system included control, test chemical, reference substance and toxicity control. Polyseed capsule (mixed culture) was used as a test inoculum for the study. Test inoculum polyseed capsule was composed of blend of specialized microbial cultures and food grade gelatin made by International Laboratory Supply (InterLab), LTD. No pretreatment / preconditioning was given to the test inoculum as the polyseed capsule requires only one hour of stirring to activate it. 1 Polyseed capsule was added in 500 mL DI water and then stirred for 1 hour for proper mixing and functioning of inoculum & settled for 15 minutes to eliminate the bran. Decanted polyseed solution was used as mixed inoculum. Thus, concentration of test inoculum used for the study was 32 ml/l which corresponds to 10E7 to 10E8 CFU/ml. The concentration of test and reference substance (Sodium Benzoate) chosen for both the study was 4 mg/L. OECD mineral medium was used for the study. ThOD (Theoretical oxygen demand) of test and reference chemical was determined by calculation. % degradation was calculated using the values of BOD and ThOD for test chemical and reference substance. The % degradation of procedure control (reference item) was also calculated using BOD & ThOD and was determined to be 61.44%. Degradation of Sodium Benzoate exceeds 39.15% on 7 days & 61.44% on 14th day. The activity of the inoculum is thus verified and the test can be considered as valid. The BOD14 value of test chemical was observed to be 1.525 mgO2/mg. ThOD was calculated as 2.54 mgO2/mg. Accordingly, the % degradation of the test chemical after 14 and 28 days of incubation at 20 ± 1°C according to Closed Bottle test was determined to be 61.02% & 57.08%. Overall, the test chemical under the test conditions, was considered to be readily biodegradable in nature.

 

In a supporting weight of evidence study from peer reviewed journal (2019), biodegradation study was conducted for 28 days for evaluating the percentage biodegradability of test chemical. The study was performed by a modified OECD screening test conducted as per the method similar to OECD Guideline 301 E (Ready biodegradability: Modified OECD Screening Test). Secondary effluent from a sewage treatment plant was used as a test inoculum. A test chemical solution was inoculated with the test inoculum in a mineral medium in test flasks and incubated further for a period of 28 days. The percentage degradation of test chemical was determined to be 89%, 94% and 100% by using DOC removal parameter after a period of 7, 14 and 21 days. Thus, based on percentage degradation, test chemical was considered to be readily biodegradable in water.

 

Additional biodegradation study was conducted for 28 days for evaluating the percentage biodegradability of test chemical (A. M. Api et. al; 2019). The study was performed in accordance with the OECD Guideline 301 F (Ready biodegradability: Manometric Respirometry Test) at 22°C. Activated sludge obtained from a wastewater treatment plant was used as a test inoculum. Test chemical concentration used for the study was 100 mg/l. A test chemical solution was inoculated with the test inoculum in a mineral medium and incubated further for a period of 28 days. The percentage degradation of test chemical was determined to be 86% by using oxygen consumption parameter after 28 days. Thus, based on percentage degradation, test chemical was considered to be readily biodegradable in water.

 

For the test chemical, biodegradation study was conducted for evaluating the percentage biodegradability of test chemical (from handbook, 2008 and secondary source, 1991). River water was used as a test inoculum. It was acclimated for 100 days. The percentage degradation of test chemical was determined to be 88% by using oxygen consumption parameter after 10 days. Thus, based on percentage degradation, test chemical was considered to be readily biodegradable in water.

 

In a supporting weight of evidence study, biodegradation experiment was conducted for determining the biodegradability of test chemical (Study report, 2015). Mixed inoculum was used as a test inoculum. The inoculum used was a diluted suspension of mixed inoculum at a concentration of 0.5 ml/L. The test system included control, test substance and reference substance. Initial test chemical concentration used for the study was 2 mg/l while that of inoculum (diluted suspension of mixed inoculum) was 0.5 ml/l. This gave the bacterial CFU/ml as 104E to 10E6. The study was performed under aerobic conditions at 20 ± 2°C for 5 days. DO determination on the 0th and 5th day of the experiment was done with the help of DO meter. The amount of oxygen taken up by the microbial population during biodegradation of the test substance was corrected for uptake by the blank inoculum and BOD5 was calculated accordingly. ThOD, BOD5 and % Degradation of both reference and the test substance were then calculated. Sodium acetate (5 mg/l) was used as a reference substance for the study and undergoes 127.65% degradation after 5 days. The BOD5 value of test chemical was observed to be 0.635 mgO2/mg. ThOD was determined by calculation as 2.542 mgO2/mg. Accordingly, the % degradation of the test chemical after 5 days of incubation at 20°C was determined to be 24.98%. Thus, test chemical was considered to be biodegradable in water.

 

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