Sodium formate

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

biodegradation in water: screening tests

Type of information:

experimental study

Adequacy of study:

other information

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

secondary literature

Remarks:

Secondary quotation as cited in ECB IUCLID; original data not available

Principles of method if other than guideline:

COD determination:
1) U.S. standard procedure (dichromate method with Ag-ion)
2) German standard procedure (dichromate method without Ag-ion)

GLP compliance:

no

Parameter:

COD

Value:

216 - 239 mg O2/g test mat.

COD values given range from 216 mg/g to 237 mg/g for results with  dichromate method (with Ag-ion) following the U.S. standard procedure);

COD result for the dichromate method (without Ag-ion) following the  German standard procedure for water,  sewage, and sludge evaluation: 239  mg/g

Reference 2

Endpoint:

biodegradation in water: screening tests

Type of information:

experimental study

Adequacy of study:

other information

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Scientifically acceptable publication

Principles of method if other than guideline:

"Standard methods for the Examination of Water, Sewage, and Industrial Wastes", 11th ed. (U.S. method)

Oxygen conditions:

aerobic

Inoculum or test system:

sewage, domestic (adaptation not specified)

Results

Nitrogen source	BOD [mg/L] after
	3 d	5 d	10 d	20 d
NH3	0.4	2.0	5.4	4.8
NO3	0.3	0.6	5.4	5.4

Nitrate dilution water was prepared using an equivalent amount of  nitrogen-nitrate instead of ammonia in the standard dilution water. 

In  tests using the Warburg respirometer, the nitrogen and phosphorus  concentrations were increased in order to maintain a BOD:N:P ratio of  100:5:1.

Each BOD value represents an average of either three or five  replicate tests.
Three series of standard dilution bottles were set up with each nitrogen  source and 2, 4, or 6 mL of sewage per bottle. 

Sodium formate was added  in a 40 mg/L concentration. BOD values were obtained after 3, 5, 10, and  20 days incubation.

Reference 3

Endpoint:

biodegradation in water: screening test, other

Type of information:

experimental study

Adequacy of study:

other information

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Reliable compilation

Principles of method if other than guideline:

BOD5 Method: "Standard Dilution Method"

GLP compliance:

no

Oxygen conditions:

aerobic

Inoculum or test system:

other: Sewage

Duration of test (contact time):

5 d

Parameter:

BOD5

Value:

0.1 g O2/g test mat.

Parameter:

BOD5

Value:

0.04 g O2/g test mat.

Two BOD5 values are listed for Na-formate in this compilation as found in the literature: 0.096 / 0.04 g/g

Reference 4

Endpoint:

biodegradation in water: ready biodegradability

Adequacy of study:

other information

Reliability:

2 (reliable with restrictions)

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 E (Ready biodegradability: Modified OECD Screening Test)

GLP compliance:

no

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic (adaptation not specified)

Initial conc.:

20 mg/L

Based on:

DOC

Value:

92

Sampling time:

21 d

Huels AG Marl
Celanese Ltd  Dallas TX

Interpretation of results:

readily biodegradable

Reference 5

Endpoint:

biodegradation in water: inherent biodegradability

Type of information:

experimental study

Adequacy of study:

other information

Reliability:

4 (not assignable)

Qualifier:

according to guideline

Guideline:

OECD Guideline 302 B (Inherent biodegradability: Zahn-Wellens/EMPA Test)

GLP compliance:

not specified

Oxygen conditions:

aerobic

Inoculum or test system:

sewage, domestic (adaptation not specified)

Duration of test (contact time):

9 d

Initial conc.:

300 mg/L

Based on:

DOC

Value:

100

Sampling time:

9 d

inoculum: activated sludge, domestic

Interpretation of results:

inherently biodegradable

Conclusions:

CL-Freetext:
inherently biodegradable

Reference 6

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

other information

Reliability:

4 (not assignable)

Qualifier:

according to guideline

Guideline:

EU Method C.4-A (Determination of the "Ready" Biodegradability - Dissolved Organic Carbon (DOC) Die-Away Test)

Version / remarks:

Cited as Directive 92/69/EEC, C.4-A

GLP compliance:

yes

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic (adaptation not specified)

Duration of test (contact time):

28 d

Initial conc.:

10 mg/L

Based on:

DOC

Value:

99.6

Sampling time:

28 d

Reference 7

Endpoint:

biodegradation in water: screening tests

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Reason / purpose for cross-reference:

reference to same study

Qualifier:

according to guideline

Guideline:

other: OECD Guideline 306 (Biodegradability in Seawater): Closed Bottle Test

Deviations:

no

GLP compliance:

yes

Oxygen conditions:

aerobic

Inoculum or test system:

other: non-specific marine microbiota (present in collected seawater)

Duration of test (contact time):

28 d

Initial conc.:

22.13 mg/L

Based on:

act. ingr.

Parameter followed for biodegradation estimation:

O2 consumption

Remarks:

(COD)

Details on study design:

TEST CONDITIONS
- Volume of test solution/treatment:
- Composition of medium: aged and decanted seawater, added mineral solutions according to guideline
- Additional substrate: no
- Solubilising agent (type and concentration if used): no
- Test temperature: 20°C±2.4°C
- pH adjusted: no
- Continuous darkness: yes
- Any indication of the test material adsorbing to the walls of the test apparatus: no

TEST SYSTEM
- Culturing apparatus: closed bottle
- Number of culture flasks/concentration: 2
- Test performed in closed vessels due to significant volatility of test substance: no
- Test performed in open system: no

SAMPLING
- Sampling frequency: sampled on day 0, 5, 15, and 28
- oxygen measurements: day 0, 5, 15, and 28 with an oximeter

CONTROL AND BLANK SYSTEM
- Inoculum blank: yes
- Toxicity control: yes

Reference substance:

benzoic acid, sodium salt

Parameter:

% degradation (O2 consumption)

Value:

7

Sampling time:

5 d

Parameter:

% degradation (O2 consumption)

Value:

74

Sampling time:

15 d

Key result

Parameter:

% degradation (O2 consumption)

Value:

86

Sampling time:

28 d

Details on results:

- Activity in the reference control was satisfactory (> 50% after 5 days).
- Oxygen depletion in the blank did not exceed 30%.

Results with reference substance:

Kinetic of control substance (in %):
82 after 5 day(s)

Time	Biodegradation (% BOD of ThOD)
(days)	Na benzoate	Na formate	Inhibition control (Na formate + Na benzoate)
0	0	0	0
5	82	7	37
15	96	74	68
28	96	86	77

- Activity in the reference control was satisfactory (> 50% after 5 days).

- Oxygen depletion in the blank did not exceed 30%.

Validity criteria fulfilled:

yes

Remarks:

The inoculum control was degraded by 82% within 5 days, therefore the inoculum activity was satisfactory. Moreover, oxygen depletion in the inoculum blank did not exceed 30% oxygen of the oxygen in the test bottle. The test is therefore considered valid.

Interpretation of results:

readily biodegradable

Conclusions:

Sodium formate is readily biodegradable (86% degradation, based on ThOD, over 28 days) (KM Lab, 1998).

Executive summary:

The biodegradability of sodium formate in seawater was investigated via a ‘Biodegradability in Seawater (closed bottle)’ study (OECD Guideline 306), which showed 86% degradation (ThOD) over 28 days (KM Lab, 1998).

According to OECD Guidance, when a chemical attains more than 60% ThOD or more than 70% DOC removal in a Biodegradability in Seawater test (OECD 306) it can also be expected to fulfil the criteria for ready biodegradability, given that the degradation potential in seawater is normally lower than in freshwater tests (OECD, 2002). Sodium formate can therefore be regarded as readily biodegradable.

Reference 8

Endpoint:

biodegradation in water: screening tests

Type of information:

experimental study

Adequacy of study:

other information

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Scientifically acceptable publication

Oxygen conditions:

anaerobic

Inoculum or test system:

other: anaerobic sediment microorganisms

The mineralization kinetics of the low molecular fatty acids and glucose in anoxic sediment were as follows:

The Vmax values for mineralization of formate were 3 orders of magnitude higher (90.8 - 637 nmol/g/h) compared to the other compounds.

Turnover time varied according to substrate and temperature, ranging from 1.5 - 4.2 h for formate to up to 70 h for acetate without molybdate. Sulfate-reducing bacteria were found to account for a significant part of the mineralization potential and turnover.

Description of key information

Sodium formate is readily biodegradable (86% degradation, based on ThOD, over 28 days) (KM Lab, 1998).

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Additional information

According to OECD Guidance, when a chemical attains more than 60% ThOD or more than 70% DOC removal in a Biodegradability in Seawater test (OECD 306) it can also be expected to fulfil the criteria for ready biodegradability, given that the degradation potential in seawater is normally lower than in freshwater tests (OECD, 2002). Sodium formate achieved 86% degradation (ThOD) over 28 days in a reliable OECD 306 study and can therefore be regarded as readily biodegradable (KM Lab, 1998).

OECD. 2002. OECD Series on Testing and Assessment: Harmonised Integrated Classification System for Human Health and Environmental Hazards of Chemical Substances and Mixtures. OECD Publishing.