L-Glutamic acid, N-coco acyl derivs., monosodium salts

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:

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:

Mixed Inoculum Preparation: Polyseed were used for this study. Polyseed capsule is a blend of broad spectrum bacteria designed specifically as seed inoculums for the BOD test. Polyseed is an EPA approved BOD seed inoculum. 38.4mg of polyseed from the capsule was weighed and added in 100 mL mineral media and then stirred for 1 h for proper mixing and functioning of inoculum. This gave the bacterial count as 10E4 to 10E6 CFU/L. A further concentration of 1 mL/L of polyseed solution is prepared and from this working inoculum 0.125 mL solution is added to every bottles of 125 mL. At the regular interval microbial plating was also performed on agar to confirm the vitality and CFU count of microorganism.

Duration of test (contact time):

42 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
- Toxicity control: it contains test chemical, reference compound (sodium benzoate), inoculum and mineral media
- Test system: it contains test chemical and inoculum

Reference substance:

benzoic acid, sodium salt

Key result

Parameter:

% degradation (O2 consumption)

Value:

52.94

Sampling time:

42 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 BOD48 value of test chemical was observed to be 0.45 mgO2/mg. ThOD was determined by calculation as 0.85 mgO2/mg. % degradation was calculated using the values of BOD and ThOD for test item and was determined to be 52.94% at 20 ± 1°C. The % degradation of procedure control (reference item) was also calculated using BOD & ThOD and was determined to be 74.85%. Degradation of Sodium Benzoate exceeds 59.88% on 7 days & 77.84% 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 74.85%. Degradation of Sodium Benzoate exceeds 59.88% on 7 days & 77.84% on 14th day. The activity of the inoculum is thus verified and the test can be considered as valid.

Results:

TABLE: D.O. values (mg/l)

No. of Days	Blank Control	Test Chemical	Procedure Control(Reference Chemical)	Toxicity Control
0	7.9	7.8	7.9	7.7
7	7.7	6.6	3.7	5.4
14	7.0	5.9	1.8	4.4
21	6.8	5.0	0.8	3.5
28	6.4	4.6	0.5	3.0
35	6.0	4.2	0.5	2.6
42	5.3	3.4	0.3	2.0

 

TABLE: BOD values (mg O2/mg)

No. of Days	Test Chemical	Procedure Control(Reference Chemical)	Toxicity Control
0	0.00	0.00	0.00
7	0.25	1.00	0.53
14	0.25	1.30	0.60
21	0.43	1.50	0.78
28	0.43	1.48	0.80
35	0.43	1.38	0.80
42	0.45	1.25	0.78

 

TABLE: %Biodegradation

No. of Days	Test Chemical	Procedure Control(Reference Chemical)	Toxicity Control
0	0.00	0.00	0.00
7	29.41	59.88	62.35
14	29.41	77.84	70.58
21	50.58	89.82	91.76
28	50.58	88.62	94.11
35	50.58	82.63	94.11
42	52.94	74.85	91.76

 

TABLE: BOD, ThOD and %Biodegradation values

Test System	BOD	ThOD (mgO2/mg)	% Biodegradation
Test Chemical	0.45	0.85	52.94
Procedure Control(Reference Chemical)	1.25	1.67	74.85
Toxicity Control	0.78	0.85	91.76

 

TABLE: pH values

No. of Days	Blank Control	Test Chemical	Procedure Control(Reference Chemical)	Toxicity Control
0	7.5	7.7	7.5	7.6
7	7.4	7.4	7.4	7.4
14	7.3	7.2	7.3	7.4
21	7.2	7.2	7.3	7.2
28	7.3	7.1	7.2	7.2
35	7.0	7.0	6.9	7.0
42	7.2	7.0	7.1	6.9

Validity criteria fulfilled:

yes

Interpretation of results:

inherently biodegradable

Conclusions:

The test chemical undergoes 52.94 % biodegradation after 28 days in the test condition. Thus, the test item was considered to be inherently biodegradable.

Executive summary:

42-days Closed Bottle test following the OECD guideline 301 D to determine the ready biodegradability of the test chemical. The study was performed at a temperature of 20°C under aerobic conditions. The test system included control, test item, reference item and toxicity control. Polyseed were used for this study. The concentration of test and reference item (Sodium Benzoate) chosen for both the study was 4 mg/L, while that of inoculum was 1 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 74.85%. Degradation of Sodium Benzoate exceeds 59.88% on 7 days & 77.84% on 14th day. The activity of the inoculum is thus verified and the test can be considered as valid. The BOD42 value of test chemical was observed to be 0.45 mgO2/mg. ThOD was calculated as 0.85 mgO2/mg. Oxygen depletion in the inoculum blank did not exceed 1.5 mg dissolved oxygen/L after 28 days. The residual conc. of oxygen in test bottles did not fall below 0.5 mg/L at any time, % degradation of reference compound has reached the pass levels (60% of ThOD) by day 14 and in a toxicity test, containing both the test substance and a reference compound, >25% biodegradation occurred within 14 days,  test substance cannot be assumed to be inhibitory. Thus, fulfilling the validity crtieria as per OECD test guideline and hence, study is considered to be valid. Accordingly, the % degradation of the test chemical after 42 days of incubation at 20 ± 1°C according to Closed Bottle test was determined to be 52.94%. Based on the results, the test chemical, under the test conditions, was considered to be inherently biodegradable in nature.

Description of key information

42-days Closed Bottle test following the OECD guideline 301 D to determine the ready biodegradability of the test chemical. The study was performed at a temperature of 20°C under aerobic conditions. The test system included control, test item, reference item and toxicity control. Polyseed were used for this study. The concentration of test and reference item (Sodium Benzoate) chosen for both the study was 4 mg/L, while that of inoculum was 1 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 74.85%. Degradation of Sodium Benzoate exceeds 59.88% on 7 days & 77.84% on 14th day. The activity of the inoculum is thus verified and the test can be considered as valid. The BOD42 value of test chemical was observed to be 0.45 mgO2/mg. ThOD was calculated as 0.85 mgO2/mg. Oxygen depletion in the inoculum blank did not exceed 1.5 mg dissolved oxygen/L after 28 days. The residual conc. of oxygen in test bottles did not fall below 0.5 mg/L at any time, % degradation of reference compound has reached the pass levels (60% of ThOD) by day 14 and in a toxicity test, containing both the test substance and a reference compound, >25% biodegradation occurred within 14 days,  test substance cannot be assumed to be inhibitory. Thus, fulfilling the validity crtieria as per OECD test guideline and hence, study is considered to be valid. Accordingly, the % degradation of the test chemical after 42 days of incubation at 20 ± 1°C according to Closed Bottle test was determined to be 52.94%. Based on the results, the test chemical, under the test conditions, was considered to be inherently biodegradable in nature.

Key value for chemical safety assessment

Biodegradation in water:

inherently biodegradable

Additional information

42-days Closed Bottle test following the OECD guideline 301 D to determine the ready biodegradability of the test chemical. The study was performed at a temperature of 20°C under aerobic conditions. The test system included control, test item, reference item and toxicity control. Polyseed were used for this study. The concentration of test and reference item (Sodium Benzoate) chosen for both the study was 4 mg/L, while that of inoculum was 1 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 74.85%. Degradation of Sodium Benzoate exceeds 59.88% on 7 days & 77.84% on 14th day. The activity of the inoculum is thus verified and the test can be considered as valid. The BOD42 value of test chemical was observed to be 0.45 mgO2/mg. ThOD was calculated as 0.85 mgO2/mg. Oxygen depletion in the inoculum blank did not exceed 1.5 mg dissolved oxygen/L after 28 days. The residual conc. of oxygen in test bottles did not fall below 0.5 mg/L at any time, % degradation of reference compound has reached the pass levels (60% of ThOD) by day 14 and in a toxicity test, containing both the test substance and a reference compound, >25% biodegradation occurred within 14 days,  test substance cannot be assumed to be inhibitory. Thus, fulfilling the validity crtieria as per OECD test guideline and hence, study is considered to be valid. Accordingly, the % degradation of the test chemical after 42 days of incubation at 20 ± 1°C according to Closed Bottle test was determined to be 52.94%. Based on the results, the test chemical, under the test conditions, was considered to be inherently biodegradable in nature.