Potassium superoxide

Short-term toxicity to fish

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

short-term toxicity to fish

Type of information:

other: evidence based on degradation product

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

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

Remarks:

RA study

Justification for type of information:

Refer to the section 13 of IUCLID dataset for details. The short term toxicity study with the degradation product is considered sufficient to fulfil the information requirements as further explained in the provided endpoint summary.

Reason / purpose for cross-reference:

read-across source

Principles of method if other than guideline:

A short-term toxicity study was conducted to determine effect of the test substance on different freshwater fish species.

GLP compliance:

no

Analytical monitoring:

yes

Test organisms (species):

other: rainbow trout (Oncorhyncus mykiss), channel catfish (Ictalurus punctatus), and bluegill (Lepomis machrochirus)

Details on test organisms:

All species and life stages used in the following tests were cultured at the UMSC.

Test type:

semi-static

Total exposure duration:

24 h

Hardness:

134 mg/L as CaCO3

Test temperature:

Water temperatures for the three species and life stages were within 1°C of the target temperature (17-22°C) throughout the studies.

pH:

7.6 to 8.2

Dissolved oxygen:

The 24-h dissolved oxygen concentrations throughout all tests exceeded 60% saturation.

Salinity:

107 mg/L as CaCO3

Nominal and measured concentrations:

Nominal: 0 to 5,000 uL/L
Actual treatment concentrations measured for tests were within 10% of the expected concentrations; mean values were within 5%.

Details on test conditions:

Species tested were:

- raindow trout (Oncorhyncus mykiss)
- channel catfish (Lactalurus punctatus)
- bluegill (Lepomis machrochirus)

- Each fish species was tested separately. 10 fish of each species was exposed to the test substance in duplicate (20 fish/exposure concentration).

Acute toxicity tests were conducted with rainbow trout, channel catfish, and bluegill to determine the effects of water temperature on the toxicity of hydrogen peroxide.

- The weight of test fish ranged from 0.9 to 1.2 g.
- Glass jars containing 15 L of well water were used to expose fish to concentrations of hydrogen peroxide ranging from 0 to 5,000 uL/L for a 24-h period. All tests were conducted in duplicate, and each exposed jar contained 10 fish (20 fish/exposure concentration).
- Tests were conducted at water temperatures 17 and 22°C. Temperatures were maintained by immersion of the jars in a circulating water bath serviced by heater-chiller units.

Reference substance (positive control):

no

Key result

Duration:

24 h

Dose descriptor:

LC50

Effect conc.:

34 other: µL/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

mortality (fish)

Remarks on result:

other: species tested: rainbow trout

Key result

Duration:

24 h

Dose descriptor:

LC50

Effect conc.:

55.5 other: µL/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

mortality (fish)

Remarks on result:

other: species tested: channel catfish

Key result

Duration:

24 h

Dose descriptor:

LC50

Effect conc.:

71.5 other: µL/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

mortality (fish)

Remarks on result:

other: species tested: bluegill

Sublethal observations / clinical signs:

For acute toxicity tests, the trimmed Spearman-Karber method was used to calculate median lethal chemical concentrations (LC50s, the concentration lethal to 50% of the treated fish) and 95% confidence intervals (CI) at 0.5, 1, 3, and 24 h, based on calculated exposure concentrations. Mortality data were pooled from the two replicates for each concentration to calculate the LC50s and 95% CIs. The LC50 values were judged to be significantly different if 95% CIs did not overlap.

Validity criteria fulfilled:

yes

Conclusions:

Under the study conditions, 24 h LC50 of the substance to the tested fish were as follows: 34 µL/L for rainbow trout, 55.5 µL/L for channel catfish and 71.5 µL/L for bluegill

Executive summary:

A study was conducted to determine the short term toxicity of the degradation product hydrogen peroxide to fish, according to a scientifically acceptable method. Three species of freshwater fish were tested: rainbow trout (Oncorhynchus mykiss), channel catfish (Ictalurus punctatus) and bluegill (Lepomis macrochirus). All groups were tested in duplicates in each exposure. The test substance was added to each stainless steel container holding fishes to yield desired treatment concentrations of 0 to 5000 µL/L. The tests were conducted at water temperatures of 17 and 22°C for 24 h. The toxicity of the test substance varied among species and was dependent on the condition of the fish and the species tested. Under the study conditions, 24 h LC50 of the substance to the tested fish were as follows: 34 µL/L for rainbow trout, 55.5 µL/L for channel catfish and 71.5 µL/L for bluegill (Rach, 1997).

Reference 2

Endpoint:

short-term toxicity to fish

Type of information:

other: evidence based on degradation product

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Remarks:

RA study

Justification for type of information:

Refer to the section 13 of IUCLID dataset for details. The short term toxicity study to fish with the degradation product is considered sufficient to fulfil the information requirements as further explained in the provided endpoint summary.

Reason / purpose for cross-reference:

read-across source

Qualifier:

according to guideline

Guideline:

EPA OTS 797.1400 (Fish Acute Toxicity Test)

Deviations:

not specified

GLP compliance:

no

Analytical monitoring:

yes

Remarks:

measured semi-quantitatively by titration

Details on sampling:

Test medium samples of all test substance groups were analysed at the beginning and at the end of each test medium renewal interval of 24 hours.

Vehicle:

no

Test organisms (species):

Pimephales promelas

Details on test organisms:

Species/strain: Fathead minnow (Pimephales promelas Rafinesque)
Source: Fish have been cultured by Burlington Research for 6 years. Starter organisms were obtained from the Aquatic Toxicology Group (Division of Environmental Management, North Carolina)
Age: Approximately 6-8 weeks
Average length at study start: 13.7 ± 1.2 mm
Food: Live brine shrimp
Feeding frequency: At least once a day (larvae 3x daily brine shrimp), no feeding during test
Acclimation: 4-weeks acclimation period to reconstituted test medium; apparently healthy fish were used for the test
Mean biomass load: 0.25 +/- 0.08 g/L
No. of fish per testing tank: 10
No. of testing tanks: 2 per concentration

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

96 h

Post exposure observation period:

not applicable

Hardness:

50 - 250 mg/L as CaCO3

Test temperature:

20 ±1°C

pH:

7.3-9.8

Dissolved oxygen:

>9.2 mg/L

Salinity:

not applicable

Conductivity:

no data

Nominal and measured concentrations:

No data

Reference substance (positive control):

no

Key result

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

16.4 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Details on results:

At the initial lower concentrations, the fish showed effects within minutes. All fish exposed to the two highest concentrations died within 12 h. No control mortality was observed.

Results with reference substance (positive control):

-

Reported statistics and error estimates:

The trimmed Spearman-Karber statistical method was used to calculate LC50 values and their 95% confidence intervals

Validity criteria fulfilled:

yes

Conclusions:

Under the study conditions, the 96 h LC50 of the substance for Pimephales promelas was determined to be 16.4 mg/L.

Executive summary:

A study was conducted to determine the short-term toxicity to fish of the degradation product hydrogen peroxide according to US EPA Guideline EPA OTS 797.1400. Fathead minnow (Pimephales promelas) were exposed for 96 h to the test substance under semi-static conditions. No information on concentration levels has been mentioned. The concentrations of the substance were measured semi-quantitatively by titration. At the initial lower concentrations, the fish showed effects within minutes. All fish exposed to the two highest concentrations died within 12 h. No control mortality was observed. Under the study conditions, the 96 h LC50 of the substance for Pimephales promelas was determined to be 16.4 mg/L (European Chemicals Bureau, 2003).

Reference 3

Endpoint:

short-term toxicity to fish

Type of information:

other: evidence based on degradation product

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

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

Remarks:

RA study

Justification for type of information:

Refer to the section 13 of IUCLID dataset for details. The short term toxicity study with the degradation product is considered sufficient to fulfil the information requirements as further explained in the provided endpoint summary.

Reason / purpose for cross-reference:

read-across source

Principles of method if other than guideline:

Channel catfish were exposed to H2O2 at various concentrations. The test solutions were renewed daily and the fish were observed for mortality during the study period of 96 h. The LD50 values were determined by probit analysis.

GLP compliance:

no

Test organisms (species):

other: Catfish

Details on test organisms:

Chanel catfish fingerlings (10-15 cm) were obtained from a commercial catfish farm.

Test type:

static

Water media type:

other: tap water

Total exposure duration:

96 h

Test temperature:

22±2°C

Nominal and measured concentrations:

Nominal concentrations: 0, 0.06, 0.12, 0.24, 0.35, 0.47, 0.71, 0.94, 1.41 or 1.88 mM

Key result

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

1.1 mmol/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Details on results:

Fish treated with ≥0.94 mM of the test substance appeared irritable within 1 h of treatment, but first mortality did not occur before 12 h. Half of the fish treated with 1.41 and 1.88 mM were dead after 24 h; after 48 h, four fish were dead in the 0.94 mM treatment. After 96 h, no fish had died in any tanks treated with less than 0.94 mM treatment. After 96 h, no fish had died in any tanks treated with less than 0.94 mM h2O2. Cumulative mortalities after 96 h were 4, 9 and 10 in tanks treated with 0.94, 1.41 and 1.88 mM H2O2 respectively. The 96 LC50 for H2O2 on catfish was 1.1 mM, and threshold toxicity (LC01) was approximately 0.5 mM.

Validity criteria fulfilled:

not applicable

Conclusions:

Under the study conditions, the 96 h LC50 of the substance in catfish was determined to be 1.1 mM.

Executive summary:

A study was conducted to determine the short term toxicity of the degradation product hydrogen peroxide to catfish. Channel catfish were exposed to the test substance at various concentrations. The test solutions were renewed daily and the fish were observed for mortality during the study period of 96 h. The LD50 values were determined by probit analysis. Under the study conditions, the 96 h LC50 of the substance in catfish was determined to be 1.1 mM (Larry, 2006).

Description of key information

Under normal use conditions, potassium superoxide is not anticipated to be exposed to the aquatic environment. Exposure to the water is only possible if KO2 is accidentally released. However, when exposed, potassium superoxide reacts rapidly with water to produce potassium hydroxide (KOH), oxygen (O2) and potassium hydrogen peroxide (KHO2), which slowly degrades to KOH, H2O2 (hydrogen peroxide) and O2. Therefore, aquatic toxicity of KO2 could be anticipated to be due, in part, to the degradation product H2O2. KOH further dissociates into potassium and hydroxyl ions which constitute normal ion pool of the medium. On the other hand, hydrogen peroxide is likely to degrade within a short time in aquatic medium due to many alternative and competitive degradation pathways. As a result, the contribution of toxicity from hydrogen peroxide is likely to be low. Overall, the aquatic toxicity of potassium superoxide is likely to be low and a quantitative estimation of the hazard potential will not be appropriate due to its rapidly changing degradation kinetics.

Additional information

A study was conducted to determine the short term toxicity of the degradation product hydrogen peroxide to fish, according to a scientifically acceptable method. Three species of freshwater fish were tested: rainbow trout (Oncorhynchus mykiss), channel catfish (Ictalurus punctatus) and bluegill (Lepomis macrochirus). All groups were tested in duplicates in each exposure. The test substance was added to each stainless steel container holding fishes to yield desired treatment concentrations of 0 to 5000 µL/L. The tests were conducted at water temperatures of 17 and 22°C for 24 h. The toxicity of the test substance varied among species and was dependent on the condition of the fish and the species tested. Under the study conditions, 24 h LC50 of the substance to the tested fish were as follows: 34 µL/L for rainbow trout, 55.5 µL/Lfor channel catfish and 71.5 µL/L for bluegill (Rach, 1997).

A study was conducted to determine the short-term toxicity to fish of the degradation product hydrogen peroxide according to US EPA Guideline EPA OTS 797.1400. Fathead minnow (Pimephales promelas) were exposed for 96 h to the test substance under semi-static conditions. No information on concentration levels has been mentioned. The concentrations of the substance were measured semi-quantitatively by titration. At the initial lower concentrations, the fish showed effects within minutes. All fish exposed to the two highest concentrations died within 12 h. No control mortality was observed. Under the study conditions, the 96 h LC50 of the substance for Pimephales promelas was determined to be 16.4 mg/L (European Chemicals Bureau, 2003).

A study was conducted to determine the short term toxicity of the degradation product hydrogen peroxide to catfish. Channel catfish were exposed to the test substance at various concentrations. The test solutions were renewed daily and the fish were observed for mortality during the study period of 96 h. The LD50 values were determined by probit analysis. Under the study conditions, the 96 h LC50 of the substance in catfish was determined to be 1.1 mM (Larry, 2006).