Potassium benzoate

Short-term toxicity to fish

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

short-term toxicity to fish

Type of information:

read-across based on grouping of substances (category approach)

Adequacy of study:

weight of evidence

Study period:

96 hours

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Justification for type of information:

As with all salts, the significance for toxicity or environmental assessment is the presence of specific ions that will form when in solution or when in biological systems. In the case of metal salts of organic acids, the cation is generally critical to determine the solubility in biological or environmental media and if the key physico-chemical properties are equivalent, the potential for hazard and environmental fate will be equivalent

Qualifier:

according to guideline

Guideline:

EPA OPP 72-1 (Fish Acute Toxicity Test)

GLP compliance:

not specified

Specific details on test material used for the study:

99% purity, qualified by GC/MS analysis

Analytical monitoring:

yes

Details on sampling:

All test mixtures sampled at 0, 24, 48, 72 and 96 hours.

Vehicle:

no

Test organisms (species):

Pimephales promelas

Details on test organisms:

Culturted at the US EPA Environmental Research LAboratory (Duluth) and the University of Wisconsin- Superior campus. Held at 25oC in flow-thorugh considition 16:8 L:D ratio.
Fed on frozen brine shrimp
33 days old at the time of testing. Maturity reached at 90 days indicating the test organisms were juvenile.

Test type:

flow-through

Water media type:

freshwater

Limit test:

no

Total exposure duration:

96 h

Hardness:

43 mg/L as CaCO3

Test temperature:

ca 24 C

pH:

ca 7.4

Dissolved oxygen:

ca 7 mg/L (equivalent to 84.72% at sea level (1 bar) and 25oC)

Nominal and measured concentrations:

No record of nominal concentrations reported though % recovery is cited as being 102%
Measured concentrations as follows:
Corrected average (over 5 days):
Control <49 mg/L
Group A =99.05mg/L
Group B =162.5 mg/L
Group C =245 mg/L
Group D=392.5 mg/L
Group E =666.5 mg/L
Group 6 =245 mg/L

Method LOD appears to be 50 mg/L

Details on test conditions:

16 hour photoperiod

Reference substance (positive control):

no

Key result

Duration:

96 h

Dose descriptor:

EC50

Effect conc.:

ca. 484 mg/L

Nominal / measured:

meas. (TWA)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Duration:

96 h

Dose descriptor:

LC0

Effect conc.:

> 392 mg/L

Nominal / measured:

meas. (TWA)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Details on results:

Affested fish were hyperactive and lost equilibrium prior to death.

Sublethal observations / clinical signs:

Group	Control	A	B	C	D	E
No fish at start of test	20 x 2 reps	20  x 2 reps	20  x 2 reps	20  x 2 reps	20  x 2 reps	20  x 2 reps
Mortalities at 48h	0 0	0 0	0 0	0 0	1 0	1 1
Mortalities at 72h	0 0	0 0	0 0	0 0	1 1	9 9
Mortalities at 96h	0 0	0 0	0 0	0 0	6 5	16 17

Validity criteria fulfilled:

not specified

Conclusions:

A dose response was observed with mortality at the highest concentrations tested.There was no mortality at 100 mg/l and classification is not triggered by this assay.Although the testing was performed on sodium salts, this is considered a valid read-across for benzoates.

Executive summary:

A dose response was observed with mortality at the highest concentrations tested. There was no mortality at 100 mg/l and classification is not triggered by this assay.

Reference 2

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

96 hours

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Justification for type of information:

The research paper cited compares toxicity of sodium, potassium and other ions and provides an indicator to test validity of read-across between potassium and sodium.
The anion (benzoate) is assessed separately.
Performing further vertebrate tests is not considered appropriate

Qualifier:

equivalent or similar to guideline

Guideline:

EPA OPP 72-1 (Fish Acute Toxicity Test)

Principles of method if other than guideline:

Toxicity tests followed the general guidance of the U.S. Environmental Protection Agency for conducting acute whole effluent toxicity tests.

GLP compliance:

not specified

Analytical monitoring:

yes

Details on sampling:

Samples taken daily

Vehicle:

no

Test organisms (species):

Pimephales promelas

Details on test organisms:

Reared on site.
Fathead minnow brood stock were cultured at 20 to 258C in tap water that was pretreated with activated carbon

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

96 h

Hardness:

Measured, but not reported

Test temperature:

25 C

pH:

Measured, but not reported

Conductivity:

Measured, but not reported

Details on test conditions:

10,000, 5,000, 2,500, 1,250 mg/l screening, reduced to 2,500, 2,000, 1,500, 1,000, 500 mg/l where toxicity was observed

Reference substance (positive control):

no

Key result

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

ca. 880 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Details on results:

Result is based on KCl; this equates to ca 450 mg/l K

Validity criteria fulfilled:

not specified

Conclusions:

Potassium is not highly toxic to fish and will not lead to the classified of potassium benzoate.

Description of key information

A dose response for benzoates was observed with mortality at the highest concentrations tested and an LC50 ca 480 mg/l. There was no mortality at 100 mg/l and classification is not triggered by this assay. Although the testing was performed on sodium salts, this is considered a valid read-across for benzoates.

Potassium has a measured LC50 of ca 450 mg/l (when assessed as potassium chloride) on freshwater fish and although more toxic than sodium chloride, this will not lead to classification requirements.

Seawater contains ca 400 mg/l K+.

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Effect concentration:

450 mg/L

Additional information

The LC50 for freshwater fish with potassium benzoate is estimated as ca 450 mg/l