Potassium salicylate

Biodegradation in water: screening tests

Administrative data

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.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2018

Report date:

2018

Materials and methods

Test guideline

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 Sodium salicylate

GLP compliance:

no

Remarks:

Test conducted originally for other purposes than REACH and thus conducted as per the OECD guidelines only.

Test material

Test material information

Constituent 1

Reference substance name:

Sodium salicylate

EC Number:

200-198-0

EC Name:

Sodium salicylate

Cas Number:

54-21-7

Molecular formula:

C7H6O3.Na

IUPAC Name:

sodium salicylate

Test material form:

solid

Details on test material:

- Name of test material (as cited in study report):sodium salicylate- Molecular formula :C7H6O3.Na- Molecular weight : 160.1035 g/mol- Substance type: organic- Physical state: solid- Smilies notation: c1(c(cccc1)O)C(=O)[O-].[Na+]- InChI: 1S/C7H6O3.Na/c8-6-4-2-1-3-5(6)7(9)10;/h1-4,8H,(H,9,10);/q;+1/p-1

Specific details on test material used for the study:

- Name of test material (IUPAC name): Sodium salicylate- Common name: Monosodium salicylate- Molecular formula: C7H6O3.Na- Molecular weight: 160.1035 g/mol- Smiles notation: c1(c(cccc1)O)C(=O)[O-].[Na+]- InChl: 1S/C7H6O3.Na/c8-6-4-2-1-3-5(6)7(9)10;/h1-4,8H,(H,9,10);/q;+1/p-1- Substance type: Organic

Study design

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 107 to 108 CFU/ml. At the regular interval microbial plating was also performed on agar to confirm the vitality and CFU count of microorganism.ORMixed Inoculum Preparation:Domestic waste water, surface soil and soil samples from polluted sites receiving predominantly domestic waste was collected and were mixed to get diluted suspension. The inoculum was kept aerobic until being used for experiment by supplying organic and inorganic sources required by micro flora to sustain at controlled laboratory conditions. This gave the bacterial count as 107 to 108 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 test substance concentration

Initial conc.:

4 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation

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

Reference substance:

other: Sodium Benzoate

Results and discussion

% Degradation

Key result

Parameter:

% degradation (O2 consumption)

Value:

96.52

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 test chemical was observed to be 1.39 mgO2/mg. ThOD was determined by calculation as 1.44 mgO2/mg. % degradation was calculated using the values of BOD and ThOD for test item and was determined to be 96.52 % at 20 ± 1°C. The % degradation of procedure control (reference item) was also calculated using BOD & ThOD and was determined to be 73.49 %. 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.

BOD5 / COD results

Results with reference substance:

The % degradation of procedure control (reference item) was also calculated using BOD & ThOD and was determined to be 73.49 %. 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.

Any other information on results incl. tables

TABLE 1

 D.O Values(mg/L)

 

No. of Days	Inoculum Blank	Test Suspension	Procedure Control
	(Control)		(Reference Item)
No. of days	Blank DO mg/l	T.S DO mg/l	Ref DO mg/l
0	7.4	7.1	6.9
3	7	5	4.6
7	6.8	4	3.7
10	6.5	3.6	2.5
14	6.4	2.9	1.8
21	6.2	1.8	1.2
28	6	1.2	0.6

 

 

 

TABLE 2

BOD values (mgO₂/mg)

 

No. of Days	Test Suspension	Procedure Control
		(Reference Item)
No. of days	BOD of TS	BOD of Ref
0	0	0
3	0.42	0.47
7	0.62	0.65
10	0.65	0.87
14	0.8	1.02
21	1.02	1.12
28	1.39	1.22

  

Table 4.

BOD28, THOD AND % BIODEGRADATION VALUES

Method details	BOD28 (mgO2/mg)	ThOD (mgO2/mg)	% Biodegradation
Test Item	1.39	1.44	96.52
Reference Item	1.22	1.66	73.4

 

 Table 5

pH OF CLOSED BOTTLE TEST

No.of Days	InoculumBlank(Control)	TestSuspension	ProcedureControl(Reference Item)
No. of days	Blank pH	T.S pH	Ref pH
0	6.6	6.7	6.8
3	7.1	7.3	6.9
7	6.8	6.7	7
10	6.9	6.5	6.5
14	6.6	6.4	6.4
21	6.6	7.2	6.5
28	6.4	6.2	6.2

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable

Conclusions:

The test chemical sodium salicylate undergoes 96.52 % biodegradation after 28 days in the test conditions. Thus, the test chemical was considered to be readily biodegradable.

Executive summary:

28-days Closed Bottle test following the OECD guideline 301 D was performed to determine the ready biodegradability of the test chemical sodium salicylate(CAS no. 54 -21 -7). The study was performed at a temperature of 20°C. The test system included control, test item and reference item. The inoculum used in this study was Polyseed. The polyseed capsule were 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 10⁷to 10⁸CFU/ml, the concentration of inoculums used in this study was 32ml/L. At the regular interval microbial plating was also performed on agar to confirm the vitality and CFU count of microorganism. The concentration of test chemical and reference item (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 item and reference item. The % degradation of procedure control (reference item) was also calculated using BOD & ThOD and was determined to be 73.49 %. 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 BOD28 value of test chemical was observed to be 1.39 mgO2/mg. ThOD was calculated as   1.44 mgO2/mg. Accordingly, the % degradation of the test chemical sodium salicylate after 28 days of incubation at 20 ± 1°C according to Closed Bottle test was determined to be 96.52 %. Based on the results, the test chemical, under the test conditions, was considered to be readily biodegradable in nature.