2'-acetonaphthone

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:

not specified

Inoculum or test system:

other: Mixed inoculum

Details on inoculum:

Mixed Inoculum Preparation: Polyseed were used for mixed inoculum. One capsule of Polyseed were added in 500 ml of DI water to make up the solution. Afterwards 1 hour of stirring were given for proper mixing of mixed 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.

Duration of test (contact time):

35 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:

33.07

Sampling time:

28 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 arereported in Tables 2 and 3, respectively. The BOD28 value of test chemical was observed to be 0.87mgO2/mg. ThOD was determined by calculation as 2.63 mgO2/mg. % Degradation was calculated using the values of BOD and ThOD for test item and was found to be 33.07% at 20 ± 1°C. The % degradation of procedure control (reference item) was also calculated using the values of BOD & ThOD and was found to be 73.49% at 20 ± 1°C. Degradation of Sodium Benzoate exceeds 31.32% on 7 days & 49.39 % on 14th day. The activity of the inoculum is thus verified and the test can be considered as valid.

Results with reference substance:

Degradation of Sodium Benzoate exceeds 31.32% on 7 days & 49.39% on 14th day. The % degradation of procedure control (reference item) was also calculated using the values of BOD & ThOD and was found to be 73.49 % at 20 ± 1°C.

TABLE 1

D.O Values(mg/L)

No. of Days	Inoculum Blank (Control)	Test Suspension	Procedure Control (Reference Item)
0	6.6	6.6	6.6
7	6	4.4	3.9
14	5.8	4	2.5
21	5.7	3.7	1.2
28	5.6	3.2	0.7
35	5.4	1.9	0.5

 

TABLE 2

BOD values (mgO2/mg)

No. of Days	Test Suspension	Procedure Control (Reference Item)
0	0	0
7	0.37	0.52
14	0.45	0.82
21	0.5	1.12
28	0.6	1.22
35	0.87	1.22

 

TABLE 3

PERCENT BIODEGRDATION RESULTS

No. of Days	Test Suspension	Procedure Control (Reference Item)
0	0%	0%
7	14.06%	31.32%
14	17.11%	49.39%
21	19.01%	67.46%
28	22.81%	73.49%
35	33.07%	73.49%

 

Table 4

BOD35, THOD AND % BIODEGRADATION VALUES

Method details	BOD35 (mgO2/mg)	ThOD (mgO2/mg)	% Biodegradation
TestItem	0.87	2.63	33.07
ReferenceItem	1.22	1.66	73.49

Validity criteria fulfilled:

yes

Interpretation of results:

inherently biodegradable, fulfilling specific criteria

Conclusions:

The test chemical undergoes 33.07 % biodegradation after 35 days in the test condition. Thus, the test chemical was considered to be primary inherently biodegradable in nature.

Executive summary:

35-days Closed Bottle test following the OECD guideline 301 D was performed to determine the ready biodegradability of the test chemical. The test system included control, test item and reference item. The concentration of test and reference item ( Sodium Benzoate) chosen for both the study was 4 mg/L, while that of inoculum was 32 ml/l. 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 BOD35 value of test chemical was observed to be 0.87 mgO2/mg. ThOD was calculated as 2.63 mgO2/mg. Accordingly, the % degradation of the test item after 35 days of incubation at 20 ± 1°C according to Closed Bottle test was determined to be 33.07 %. Based on the results, the test chemical, under the test conditions was considered to be primary inherently biodegradable at 20 ± 1°C over a period of 35 days.

Description of key information

35-days Closed Bottle test following the OECD guideline 301 D was performed to determine the ready biodegradability of the test chemical. The test system included control, test item and reference item. The concentration of test and reference item ( Sodium Benzoate) chosen for both the study was 4 mg/L, while that of inoculum was 32 ml/l. 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 BOD35 value of test chemical was observed to be 0.87 mgO2/mg. ThOD was calculated as 2.63 mgO2/mg. Accordingly, the % degradation of the test item after 35 days of incubation at 20 ± 1°C according to Closed Bottle test was determined to be 33.07 %. Based on the results, the test chemical, under the test conditions was considered to be primary inherently biodegradable at 20 ± 1°C over a period of 35 days.

Key value for chemical safety assessment

Biodegradation in water:

inherently biodegradable

Additional information

35-days Closed Bottle test following the OECD guideline 301 D was performed to determine the ready biodegradability of the test chemical. The test system included control, test item and reference item. The concentration of test and reference item ( Sodium Benzoate) chosen for both the study was 4 mg/L, while that of inoculum was 32 ml/l. 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 BOD 35 value of test chemical was observed to be 0.87 mgO2/mg. ThOD was calculated as 2.63 mgO2/mg. Accordingly, the % degradation of the test item after 35 days of incubation at 20 ± 1°C according to Closed Bottle test was determined to be 33.07 %. Based on the results, the test chemical, under the test conditions was considered to be primary inherently biodegradable at 20 ± 1°C over a period of 35 days.