N-tert-butylacrylamide

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:

1 (reliable without restriction)

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)

Principles of method if other than guideline:

Biodegradation study was conducted according to OECD Guideline 301 D (Ready Biodegradability: Closed Bottle Test) for evaluating the percentage biodegradability of test substance.

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. 1 polyseed capsule was added in 500 ml D.I water and then stirred for 1 hour for proper mixing and functioning of inoculum.

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

Reference substance:

other: Sodium Benzoate

Key result

Parameter:

% degradation (O2 consumption)

Value:

35.39

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 BOD42 value of test chemical was observed to be 0.8 mgO2/mg. ThOD was determined by calculation as 2.26 mgO2/mg. % degradation was calculated using the values of BOD and ThOD for test item and was determined to be 35.39 % at 20 ± 1°C. The % degradation of procedure control (reference item) was also calculated using BOD & ThOD and was determined to be 78.31%. Degradation of Sodium Benzoate exceeds 42.16 % on 7 days & 63.25 % 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 78.31%. Degradation of Sodium Benzoate exceeds 42.16 % on 7 days & 63.25 % 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)
0	7	6.6	7
7	6.8	5.2	4
14	6.5	3.5	2.3
21	6.2	2.8	1.5
28	5.9	2.3	0.6
35	5.8	2	0.3
42	5.4	1.8	0.2

 

TABLE 2

BOD values (mgO2/mg)

No. of Days	Test Suspension	Procedure Control (Reference Item)
0	0	0
7	0.3	0.7
14	0.65	1.05
21	0.75	1.17
28	0.8	1.32
35	0.85	1.37
42	0.8	1.3

 

 

 

TABLE 3

PERCENT BIODEGRDATION RESULTS

No. of Days	Test Suspension	Procedure Control (Reference Item)
0	0%	0%
7	13.27%	42.16%
14	28.76%	63.25%
21	33.18%	70.48%
28	35.39%	79.51%
35	37.61%	82.53%
42	35.39%	78.31

 

 

Table 4

BOD42, THOD AND % BIODEGRADATION VALUES

Method details	BOD42 (mgO2/mg)	ThOD (mgO2/mg)	% Biodegradation
TestItem	0.80	2.26	35.39
ReferenceItem	1.30	1.66	78.31

Validity criteria fulfilled:

yes

Interpretation of results:

other: primary inherently biodegradable

Conclusions:

The test chemical undergoes 35.39 % biodegradation after 42 days in the test condition. Thus, the test item was considered to be primary inherently biodegradable.

Executive summary:

42-days Closed Bottle test following the OECD guideline 301 D was performed to determine the ready biodegradability of the test item. The study was performed at a temperature of 20°C. The test system included control, test item and reference item. Polyseed were used as a test inoculum.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 78.31  %. Degradation of Sodium Benzoate exceeds 42.16  % on 7 days &  63.25 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 0.8 mgO2/mg. ThOD was calculated as 2.26 mgO2/mg. Accordingly, the % degradation of the test item after 42 days of incubation at 20 ± 1°C according to Closed Bottle test was determined to be  35.39 %. Based on the results, the test item, under the test conditions, was considered to be primary inherently biodegradable in nature.

Description of key information

The test chemical undergoes 35.39 % biodegradation after 42 days in the test condition. Thus, the test item was considered to be primary inherently biodegradable.

Key value for chemical safety assessment

Biodegradation in water:

inherently biodegradable

Additional information

42-days Closed Bottle test following the OECD guideline 301 D was performed to determine the ready biodegradability of the test item. The study was performed at a temperature of 20°C. The test system included control, test item and reference item. Polyseed were used as a test inoculum.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 78.31  %. Degradation of Sodium Benzoate exceeds 42.16  % on 7 days &  63.25 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 0.8 mgO2/mg. ThOD was calculated as 2.26 mgO2/mg. Accordingly, the % degradation of the test item after 42 days of incubation at 20 ± 1°C according to Closed Bottle test was determined to be  35.39 %. Based on the results, the test item, under the test conditions, was considered to be primary inherently biodegradable in nature.