2-ethoxybenzoic acid

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

Study period:

23-08-2018 to 21-09-2018

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 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. 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):

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:

other: Sodium Benzoate

Parameter:

% degradation (O2 consumption)

Value:

70.31

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 are reported in Tables 2 and 3, respectively. The BOD28 value of 2-ethoxy benzoic acid (pure)(CAS No.134-11-2) was observed to be 1.35 mgO2/mg. ThOD was determined by calculation as 1.92 mgO2/mg. % Degradation was calculated using the values of BOD and ThOD for test item and was found to be 70.31% at 20 ± 1°C. The % degradation of procedure control (reference item) was also calculated using BOD & ThOD and was found to be 84.33%. Degradation of Sodium benzoate exceeds 72.28 % on 7 days & 85.54 % on 14th day. The activity of the inoculum was 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 found to be 84.33%. Degradation of Sodium benzoate exceeds 72.28 % on 7 days & 85.54 % on 14th day. The activity of the inoculum was 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	6.7	6.8
7	6.8	2	1.8
14	6.6	0.8	0.7
21	6.3	0.5	0.3
28	6.1	0.4	0.3

Table:2 BOD values (mgO2/mg)

No. of Days	Test Suspension	Procedure Control (Reference Item)
0	0	0
7	1.12	1.2
14	1.37	1.42
21	1.45	1.45
28	1.35	1.4

 

Table: 3 PERCENT BIODEGRDATION RESULTS

No. of Days	Test Suspension	Procedure Control (Reference Item)
0	0%	0%
7	58.33%	72.28%
14	71.35%	85.54%
21	75.52%	87.34%
28	70.31%	84.33%
%	%

Table 4: BOD28, THOD AND % BIODEGRADATION VALUES

Method details	BOD28 (mgO2/mg)	ThOD (mgO2/mg)	% Biodegradation
Test Item	1.35	1.92	70.31
Reference Item	1.40	1.66	84.33

 

Table 5: pH OF CLOSED BOTTLE TEST

No. of Days	Inoculum Blank (Control)	Test Suspension	Procedure Control (Reference Item)
0	7	7	6.9
7	6.8	6.9	6.7
14	6.7	6.7	6.8
21	6.9	6.6	6.6
28	6.7	6.6	6.6

Validity criteria fulfilled:

yes

Interpretation of results:

other: readily biodegradable

Conclusions:

The test item undergoes 70.31 % biodegradation after 28 days in the test condition. Thus, the test item was considered to be readily biodegradable.

Executive summary:

A 28-days Closed Bottle test following the OECD guideline 301D to determine the ready biodegradability of 2-ethoxy benzoic acid (pure), CAS No.134-11-2. 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 BOD28 value of 2-ethoxybenzoic acid (pure), CAS No. 134-11-2 was observed to be 1.35 mgO2/mg. ThOD was calculated as 1.92 mgO2/mg. Accordingly, the % degradation of the test item after 28 days of incubation at 20 ± 1°C according to Closed Bottle test was determined to be 70.31%.Based on the results, the test item, under the test conditions, was considered to be readily biodegradable in nature.

Description of key information

Accordingly, the % degradation of the test item after 28 days of incubation at 20 ± 1°C according to Closed Bottle test was determined to be 70.31%.Based on the results, the test item, under the test conditions, was considered to be readily biodegradable in nature.

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Additional information

A 28-days Closed Bottle test following the OECD guideline 301D to determine the ready biodegradability of 2-ethoxy benzoic acid (pure), CAS No.134-11-2. 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 BOD28 value of 2-ethoxybenzoic acid (pure), CAS No. 134-11-2 was observed to be 1.35 mgO2/mg. ThOD was calculated as 1.92 mgO2/mg. Accordingly, the % degradation of the test item after 28 days of incubation at 20 ± 1°C according to Closed Bottle test was determined to be 70.31%.Based on the results, the test item, under the test conditions, was considered to be readily biodegradable in nature.