Potassium superoxide

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

short-term toxicity to aquatic invertebrates

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

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 study was performed to assess the toxicity of the substance to Moina sp. and Daphnia carinata. 20 adult Daphnia or Moina were exposed to different concentrations of the test substances within the range of 1 to 12,500 mg∕L. Three replicates were prepared for each treatment and per controls. Observations for survival were made at 1, 2, 3, 4, 5, 6, 9, 12, 24, and 48 hours. The LC50 was quantified first by fitting linear regression models to each data set and subsequently by probit analysis.

GLP compliance:

not specified

Test organisms (species):

other: Moina sp. and Daphnia carinata

Details on test organisms:

Experiments were performed with animals from clonal cultures of Moina sp. (originally from Wundowie wastewater treatment plant, Western Australia) and Daphnia carinata (sensu lato) (originally from Sir James Mitchell Park Pond, Perth, Western Australia).

Test type:

static

Total exposure duration:

48 h

Test temperature:

21°C

Details on test conditions:

The clonal cultures were kept in 1.2 μm filtered water from the mesotrophic Jackadder Lake (Perth) at 21°C with a dark: light cycle of 12:12 h, and were fed ad libitum with Desmodesmus sp. (Chlorophyta) (CSIRO). The experiments were performed at 21°C under low-fluorescent light conditions to prevent the degradation of the test substance and avoid any confounding effects that different sensitivities of the two study organisms toward UV light would have.

Key result

Duration:

48 h

Dose descriptor:

LC50

Remarks:

Daphnia

Effect conc.:

5.6 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Key result

Duration:

48 h

Dose descriptor:

LC50

Remarks:

Moina

Effect conc.:

2 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Details on results:

Both Daphnia and Moina were highly sensitive to the test substance; however, the results indicate that Daphnia is less susceptible than Moina. Concentrations ≥6 mg/L led to a mortality of 100% within the first 12 h for Moina, whereas the corresponding concentration was higher by an order of magnitude for Daphnia (>40 mg/L). Linear regression revealed that Daphnia had a 48 h LC50 of 5.7 mg/L, whereas Moina had a 48 h LC50 of 1.9 mg/L. When the LC50 was computed with the probit analysis, the 48 h LC50 was 5.6 mg/L for Daphnia (95% confidence interval: 5–6.3 mg/L), and 2 mg/L for Moina. No 95% confidence interval was calculated for Moina because of too few concentrations that led to < 100% mortality. Mean survival time was significantly higher in Daphnia than in Moina at concentrations ≥2 mg/L.

Validity criteria fulfilled:

not specified

Conclusions:

Under the study conditions, the 48 h LC50 of the substance was 5.6 mg/L in Daphnia and 2 mg/L in Moina.

Executive summary:

A study was conducted to determine the short term toxicity of the degradation product hydrogen peroxide in Moina sp. and Daphnia carinata. Two days before the start of each experiment, 20 adult Daphnia or Moina were transferred into 0.5 L of 1.2 μm filtered lake water to allow for acclimatization, and fed daily with 1 mg carbon equivalent of Desmodesmus sp. Throughout the experiment Moina sp. were exposed to 14 different concentrations and Daphnids were exposed to 16 different concentrations within the range of 1 to 12,500 mg/L. Three replicates were prepared for each treatment and per control. Observations for survival were made at 1, 2, 3, 4, 5, 6, 9, 12, 24, and 48 hours at which time the experiment was stopped. The LC50 for Daphnia and Moina were quantified first by fitting linear regression models to each data set and subsequently by probit analysis. Under the study conditions, the 48 h LC50 of the substance was 5.6 mg/L in Daphnia and 2 mg/L in Moina (Reichwaldt, 2012).

Reference 2

Endpoint:

short-term toxicity to aquatic invertebrates

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:

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

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:

Groups of 20 Daphnia (divided in two replicates), 24 h old or less, were exposed to several test substance concentrations. Immobility was determined after 24 h. No analytical verification was conducted.

GLP compliance:

no

Specific details on test material used for the study:

- Stock solution concentrated at 30%

Analytical monitoring:

no

Vehicle:

no

Test organisms (species):

Daphnia magna

Details on test organisms:

- Strain/clone: IRCHA
- Age at test start: max. 24 h old

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

24 h

Test temperature:

20°C

pH:

8.0 +/- 0.2

Dissolved oxygen:

≥2 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: Glass vessels, 50 mL
- Type (delete if not applicable): open but looseley covered with filter paper
- Fill volume: 20 ml
- Aeration: no
- No. of vessels per concentration (replicates): 2
- Biomass loading rate: 10 Daphnia/vessel

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Synthetic medium according to DIN 38412, Part 1

OTHER TEST CONDITIONS
- Adjustment of pH: no

Reference substance (positive control):

yes

Remarks:

Potassium dichromate

Key result

Duration:

24 h

Dose descriptor:

EC50

Effect conc.:

7.7 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

mobility

Remarks on result:

other: (95% CI: 6.7-8.7 mg/L)

Results with reference substance (positive control):

The EC50 values for potassium dichromate was 1.3 mg/L (indicated range for this substance: 0.9-1.9 mg/L).

Validity criteria fulfilled:

not specified

Conclusions:

Under the study conditions, the nominal 24 h EC50 of the substance in Daphnia magna was determined to be 7.7 mg/L.

Executive summary:

A study was conducted to determine the acute toxicity of the degradation product hydrogen peroxide to Daphnia magna. Twenty Daphnia per group (divided in two replicates), 24 h old or less, were exposed to several concentrations of the substance. Immobility was determined after 24 h. No analytical verification of the concentration was conducted. Under the study conditions, the nominal 24 h EC50 of the substance in Daphnia magna was determined to be 7.7 mg/L (Bringmann, 1982).

Reference 3

Endpoint:

short-term toxicity to aquatic invertebrates

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

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

Qualifier:

according to guideline

Guideline:

EPA OTS 797.1300 (Aquatic Invertebrate Acute Toxicity Test, Freshwater Daphnids)

GLP compliance:

no

Analytical monitoring:

yes

Remarks:

measured semi-quantitatively

Details on sampling:

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

Vehicle:

no

Details on test solutions:

1% w/v stock solutions were prepared in reconstituted water

Test organisms (species):

Daphnia pulex

Details on test organisms:

Strain: freshwater waterflea (Daphnia pulex Leydig emend. Richard)
Source: in-house breeding from a starting population obtained from the Aquatic Toxicology Group, Water Quality Section, North Carolina Quality Section, North Carolina Division of Enviromental Management, Raleigh
Age at study initiation (mean and range, SD): 12 - 24 hours
Food type: Greenalgae Selenastrum capricornutum, suspension of digested salmon chow, yeast and CEROPHYLL
Photoperiod: cultures are illuminated by ambient fluorescent laboratory light (500 lux) supplemented by a single fluroescent tube placed 30 cm above the cultures. A 16 hours light: 8 hours darkness photoperiod is maintained.
No. of test animals: 10 per vessel

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Post exposure observation period:

not applicable

Hardness:

50 - 250 mg/L as CaCO3

Test temperature:

20 ± 1°C

pH:

6.8-9.9

Dissolved oxygen:

≥ 96% saturation

Salinity:

not applicable

Details on test conditions:

No. of vessels per concentration: 1
Controls: 2 controls

Reference substance (positive control):

no

Key result

Duration:

48 h

Dose descriptor:

LC50

Effect conc.:

2.4 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

mortality

Validity criteria fulfilled:

not specified

Conclusions:

Under the study conditions, the 48 h LC50 of the substance in Daphnia pulex was determined to be 2.4 mg/L.

Executive summary:

A study was conducted to determine the short-term toxicity to aquatic invertebrates of the degradation product hydrogen peroxide according to US EPA Guideline EPA OTS 797.1300. Daphnia pulex were exposed for 48 h to the test substance under semi-static conditions. No information on concentration levels has been mentioned. The concentrations of the test substance were measured semi-quantitatively. The validity criteria of the test were fulfilled in the sense that no mortality (evaluated as the cessation of motion of the body or appendages) was observed in the controls. Under the study conditions, the 48 h LC50 of the substance in Daphnia pulex was determined to be 2.4 mg/L (European Chemicals Bureau, 2003).

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 in Moina sp. and Daphnia carinata. Two days before the start of each experiment, 20 adult Daphnia or Moina were transferred into 0.5 L of 1.2 μm filtered lake water to allow for acclimatization, and fed daily with 1 mg carbon equivalent of Desmodesmus sp. Throughout the experiment Moina sp. were exposed to 14 different concentrations and Daphnids were exposed to 16 different concentrations within the range of 1 to 12,500 mg/L. Three replicates were prepared for each treatment and per control. Observations for survival were made at 1, 2, 3, 4, 5, 6, 9, 12, 24, and 48 hours at which time the experiment was stopped. The LC50 for Daphnia and Moina were quantified first by fitting linear regression models to each data set and subsequently by probit analysis. Under the study conditions, the 48 h LC50 of the substance was 5.6 mg/L in Daphnia and 2 mg/L in Moina (Reichwaldt, 2012).

A study was conducted to determine the short-term toxicity to aquatic invertebrates of the degradation product hydrogen peroxide according to US EPA Guideline EPA OTS 797.1300. Daphnia pulex were exposed for 48 h to the test substance under semi-static conditions. No information on concentration levels has been mentioned. The concentrations of the test substance were measured semi-quantitatively. The validity criteria of the test were fulfilled in the sense that no mortality (evaluated as the cessation of motion of the body or appendages) was observed in the controls. Under the study conditions, the 48 h LC50 of the substance in Daphnia pulex was determined to be 2.4 mg/L (European Chemicals Bureau, 2003).

A study was conducted to determine the acute toxicity of the degradation product hydrogen peroxide to Daphnia magna. Twenty Daphnia per group (divided in two replicates), 24 h old or less, were exposed to several concentrations of the substance. Immobility was determined after 24 h. No analytical verification of the concentration was conducted. Under the study conditions, the nominal 24 h EC50 of the substance in Daphnia magna was determined to be 7.7 mg/L (Bringmann, 1982).