Sodium formate

Long-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

long-term toxicity to aquatic invertebrates

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:

read-across source

Qualifier:

according to guideline

Guideline:

OECD Guideline 211 (Daphnia magna Reproduction Test)

GLP compliance:

yes

Analytical monitoring:

yes

Vehicle:

no

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: Daphnia magna Straus
- Age of parental stock (mean and range, SD): 2-4 weeks
- Age of test animals: 2- < 24 h
- Feeding during test
- Food type: algal suspension (Desmosdesmus subspicatus)
- Amount: 0.10-0.20 mg TOC/parent animal/day
- Frequency: daily

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

21 d

Test temperature:

19.5-20.4 °C

pH:

7.0-8.3

Dissolved oxygen:

8.0-9.5 mg/l

Nominal and measured concentrations:

0.0, 1.0, 3.2, 10, 32 (neutralised), and 100 (neutralised) mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: 100-ml glass beakers, covered with glass caps
- Material, size, headspace, fill volume: 50 mL
- Renewal rate of test solution (frequency/flow rate): semistatic conditions: renewal on Mondays, Wednesdays, Fridays
- No. of vessels per concentration (replicates): 10
- Biomass loading rate: 1 parent animal/vessel, 50 mL/parent animal

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: synthetic freshwater according to OECD guideline 211

OTHER TEST CONDITIONS
- Photoperiod: 16 h light, 8 h darkness
- Light intensity: artificial light, type warm white (OSRAM L58 W31)

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- measurements:       
- number of young daphnids (daily)      
- mortality, embryos, aborted eggs (daily)      
- weight and length of parent animals (end of exposure)      
- test substance (at renewal of test solution: old and new test solution)      
- pH and dissolved oxygen (at renewal of test solution: old and new test solution)      
- temperature (continuously in separate vessel)

Duration:

21 d

Dose descriptor:

NOEC

Effect conc.:

>= 100 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

reproduction

Duration:

21 d

Dose descriptor:

LOEC

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

reproduction

Duration:

21 d

Dose descriptor:

other: EC0

Effect conc.:

>= 100 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

immobilisation

Details on results:

No adverse effects on reproduction, weight or length were observed at the highest nominal exposure concentration of 100 mg/L. The 21 day NOEC for Daphnia magna exposed to formic acid was therefore100 mg/L and the LOEC was >100 mg/L.

Reported statistics and error estimates:

For the statistical evaluation of the LOEC and NOEC Dunnett's test was used to analyse the parameters: 
- number of living young (one-sided analysis)
- length and weight (two-sided analysis).
- Dunnett CW (1955). J Ameri Statist Assoc 50: 1096-1121.
- Dunnett CW (1964). Biometrics 20: 482-491.

No adverse effects (reproduction, weight, length) were observed up to the highest concentration of 100 mg/l. 

NOEC >= 100 mg/l
LOEC > 100 mg/l

swimming ability of parent animals:
EC0 >= 100 mg/l

Nominal conc. (mg/L)	Total number of living young per surviving parent animal after 21 d exposure
	min	max	mean	sd	cv (%)
0	91	150	109.7	15.8	14.4
1	88	113	102.6	7.5	7.33
3.2 *	94	135	110.2	14.8	13.4
10	79	141	108.7	19.0	17.5
32 n	85	137	105.5	14.6	13.8
100 n	92	129	110.0	11.9	10.8

*: 1 parent animal died on day 16
n: neutralised

Nominal conc. (mg/L)	Parental animal condition after 21 d exposure
	weight (mg)			length (mm)
	mean	sd	cv (%)	mean	sd	cv (%)
0	1.0	0.2	17.64	3.98	0.17	4.23
1	1.0	0.3	24.83	3.93	0.10	2.51
3.2 (*)	1.1	0.2	15.64	4.05	0.17	4.30
10	1.1	0.2	18.19	3.97	0.11	2.66
32n	1.0	0.1	13.79	3.91	0.09	2.42
100n	1.0	0.2	21.21	3.95	0.11	2.87

*: 1 parent animal died on day 16
n: neutralised

- test substance concentrations: The analytically determined concentrations of the test substance were in a range of +- 20 % of the nominal concentration in all tested concentrations and remained constant over the exposure period.

Validity criteria fulfilled:

yes

Conclusions:

No adverse effects on reproduction, weight or length were observed at the highest nominal exposure concentration of 100 mg/L. The 21 day NOEC for Daphnia magna exposed to formic acid was therefore100 mg/L and the LOEC was >100 mg/L.

Executive summary:

The effects of formic acid on Daphnia magna survival and reproduction were determined. The study was carried out according to the OECD Guideline 211 (Daphnia magna reduction test), 2012. In this study Daphnia were exposed to formic over a test period of 21 days under semi- conditions. Nominal exposure concentrations were 0 (control), 1.0, 3.2, 10 32 (neutralised) and 100 (neutralised) mg/L.  The results of the study were based on the nominal concentrations.

No adverse effects on reproduction, weight or length were observed at the highest nominal exposure concentration of 100 mg/L. The 21 day NOEC for Daphnia magna exposed to formic acid was therefore100 mg/L and the LOEC was >100 mg/L.

Reference 2

Endpoint:

long-term toxicity to aquatic invertebrates

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Justification for type of information:

It is considered appropriate to address the long-term toxicity to aquatic invertebrates data requirement for sodium formate by read-across to an available study on formic acid.
Sodium formate is the sodium salt of formic acid and will dissociate immediately in aqueous and biological surroundings to the formate ion. It is therefore expected that the environmental profile of formic acid and sodium formate will be similar.

Reason / purpose for cross-reference:

read-across source

Specific details on test material used for the study:

Formic acid is being used as a read-across for sodium formate.

Key result

Duration:

21 d

Dose descriptor:

NOEC

Effect conc.:

100 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

reproduction

Duration:

21 d

Dose descriptor:

LOEC

Effect conc.:

>= 100 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

reproduction

Duration:

21 d

Dose descriptor:

LC10

Effect conc.:

>= 100 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

mortality

Details on results:

No adverse effects on reproduction, weight or length were observed at the highest nominal exposure concentration of 100 mg/L. The 21 day NOEC for Daphnia magna exposed to formic acid was therefore100 mg/L and the LOEC was >100 mg/L.

No adverse effects (reproduction, weight, length) were observed up to the highest concentration of 100 mg/l. 

NOEC >= 100 mg/l
LOEC > 100 mg/l

swimming ability of parent animals:
EC0 >= 100 mg/l

Nominal conc. (mg/L)	Total number of living young per surviving parent animal after 21 d exposure
	min	max	mean	sd	cv (%)
0	91	150	109.7	15.8	14.4
1	88	113	102.6	7.5	7.33
3.2 *	94	135	110.2	14.8	13.4
10	79	141	108.7	19.0	17.5
32 n	85	137	105.5	14.6	13.8
100 n	92	129	110.0	11.9	10.8

*: 1 parent animal died on day 16
n: neutralised

Nominal conc. (mg/L)	Parental animal condition after 21 d exposure
	weight (mg)			length (mm)
	mean	sd	cv (%)	mean	sd	cv (%)
0	1.0	0.2	17.64	3.98	0.17	4.23
1	1.0	0.3	24.83	3.93	0.10	2.51
3.2 (*)	1.1	0.2	15.64	4.05	0.17	4.30
10	1.1	0.2	18.19	3.97	0.11	2.66
32n	1.0	0.1	13.79	3.91	0.09	2.42
100n	1.0	0.2	21.21	3.95	0.11	2.87

*: 1 parent animal died on day 16
n: neutralised

- test substance concentrations: The analytically determined concentrations of the test substance were in a range of +- 20 %

 of the nominal concentration in all tested concentrations and remained constant over the exposure period.

Validity criteria fulfilled:

yes

Conclusions:

No adverse effects on reproduction, weight or length were observed at the highest nominal exposure concentration of 100 mg/L. The 21 day NOEC for Daphnia magna exposed to formic acid was therefore100 mg/L and the LOEC was >100 mg/L.

Executive summary:

The effects of formic acid on Daphnia magna survival and reproduction were determined. The study was carried out according to the OECD Guideline 211 (Daphnia magna reduction test), 2012. In this study Daphnia were exposed to formic over a test period of 21 days under semi- conditions. Nominal exposure concentrations were 0 (control), 1.0, 3.2, 10 32 (neutralised) and 100 (neutralised) mg/L.  The results of the study were based on the nominal concentrations.

No adverse effects on reproduction, weight or length were observed at the highest nominal exposure concentration of 100 mg/L. The 21 day NOEC for Daphnia magna exposed to formic acid was therefore100 mg/L and the LOEC was >100 mg/L.

Description of key information

With high probability not chronically toxic to aquatic invertebrates. 

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

100 mg/L

Additional information

To determine chronic effects of formic acid to aquatic invertebrates, a semi-static GLP study according to OECD guideline 211 using Daphnia magna was performed. The calculated NOEC value (21d) in this study was 100 mg/L, related to the nominal concentrations which were verified analytically (BASF SE 2007).