Potassium benzoate

Long-term toxicity to fish

Administrative data

Endpoint:

adult fish: sub(lethal) effects

Data waiving:

study scientifically not necessary / other information available

Justification for data waiving:

other:

Justification for type of information:

Benzoates exhibit low toxicity to aquatic organisms and will rapidly biodegrade
Potasium is present at typical concentrations of 1.5 mg/l in freshwater and 400 mg/l in seawater
Further testing on vertebrates cannot be justified.

Cross-reference

Cross-reference 1

Reason / purpose for cross-reference:

data waiving: supporting information

Reference

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

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

Adequacy of study:

weight of evidence

Study period:

28 day Ready Biodegradation

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

test procedure in accordance with generally accepted scientific standards and described in sufficient detail

Justification for type of information:

Benzoate salts – justification for read-across. 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; this is especially so for potassium and sodium salts that share similar solubility and dissociation characteristics.The cation is only critical in determining hazard if this is itself hazardous, but if the metal cations are present in the diet or are ‘essential’ elements for health, then there should be little to differentiated long-term hazards.
It is considered that potassium and sodium salts will behave in the same way under environmental conditions.

Qualifier:

equivalent or similar to guideline

Guideline:

EU Method C.4-D (Determination of the "Ready" Biodegradability - Manometric Respirometry Test)

Version / remarks:

The aim of this ring-test programme was to examine the reliability of a method of assessing the biodegradability of chemical substances based on a UK adaptation of the Japanese MITI test so that it may be included in Annex V of the Directive 79/831/CEE.

Principles of method if other than guideline:

Test performed at 12 different laboratories as part of a method validation exercise. Sodium benzoate is usd as a reference substance for biodegradation testing

GLP compliance:

not specified

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, non-adapted

Details on inoculum:

Inoculum sludge grown on sewage

Duration of test (contact time):

28 d

Based on:

not specified

Remarks:

Range used

Parameter followed for biodegradation estimation:

O2 consumption

Reference substance:

not required

Remarks:

The research was to confirm sodium benzoate as a reference substance

Key result

Parameter:

% degradation (DOC removal)

Value:

64 - 97

Sampling time:

10 d

Parameter:

% degradation (DOC removal)

Value:

75 - 100

Sampling time:

28 d

Details on results:

As expected, sodium benzoate was readily degraded and values of biodegradation from all laboratories exceeded 60% after 14 days, t + 10 days

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable

Conclusions:

As expected, sodium benzoate was readily degraded and values of biodegradation from all laboratories exceeded 60% after 14 days, t + 10 days

Executive summary:

Test performed at 12 different laboratories as part of a method validation exercise. Sodium benzoate is used as a reference substance for biodegradation testing

A good level of biodegradation is noted with both benzoic acid and the sodium salt. 

Sodium benzoate is used as a reference substance for biodegradation testing and it is considered that potassium benzoate will behave in the same way.

Potassium and sodium benzoate dissociate under environmental conditions and the organic components will behave the same irrespective of the mono-valent metal ion associated with it.

Benzoate is rapidly biodegradable under aerobic conditions

Cross-reference 2

Reason / purpose for cross-reference:

data waiving: supporting information

Reference

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.

Cross-reference 3

Reason / purpose for cross-reference:

data waiving: supporting information

Reference

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.