Potassium iodate

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

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

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

data from handbook or collection of data

Remarks:

Experimental data of various test chemicals

Justification for type of information:

Experimental data of various test chemicals is from collection of data

Reason / purpose for cross-reference:

read-across source

Reason / purpose for cross-reference:

read-across source

Reason / purpose for cross-reference:

read-across source

Qualifier:

according to guideline

Guideline:

other: As mention below

Principles of method if other than guideline:

WoE report is based on three short term toxicity study of test chemical on aquatic algae and cyanobacteria.

GLP compliance:

no

Analytical monitoring:

no

Vehicle:

not specified

Test organisms (species):

other: 1: Dunaliella salina, 2: Chlorella sp., 3: Cryptomonas sp.

Details on test organisms:

1: Serial concentrations of test chemical were supplemented into the modified medium for the culture of Dunaliella salina.
2: Serial concentrations of test chemical were supplemented into the f/2 medium for Chlorella sp.
3: Serial concentrations of potassium iodide were supplemented into the f/2 medium for Cryptomonas sp.

Test type:

static

Water media type:

other: 1: saltwater, 2: brackish water

Total exposure duration:

10 d

Test temperature:

25 deg C

Dissolved oxygen:

above 45% saturation.

Details on test conditions:

The inocula, each containing 3 × 10(4) alga cells, were added to 10mL of the corresponding media and incubated in an oscillator shaker at a rate of 150 rpm under light irradiation of 81.04μmolm−2 s−1 and a 12 h/12 h light/dark cycle.

Reference substance (positive control):

no

Duration:

10 d

Dose descriptor:

other: MIC

Effect conc.:

356.8 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: 1st study

Duration:

10 d

Dose descriptor:

other: MIC

Effect conc.:

696.2 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: 2nd study

Duration:

10 d

Dose descriptor:

other: MIC

Effect conc.:

475.9 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: 3rd study

Details on results:

The growth of algae was determined by counting the number of cells using a haemacytometer. The minimum concentration of test chemical that inhibited growth was designated as MIC100.

Validity criteria fulfilled:

no

Conclusions:

1: Minimum Inhibitory Concentration (MIC100) value of test chemical in green algae (Dunaliella salina) in a 10 days. study on growth effect was determine to be 356.8 mg/L.Thus considering CLP Criteria for aquatic classification of the substance, it is concluded that test chemical does not exhibit toxicity to green algae (Dunaliella salina).
2: Minimum Inhibitory Concentration (MIC100) of test chemical in green algae (Chlorella sp.) in a 10 days study on growth effect was observed to be 696.2 ± 9.4 mg/L.
3: Minimum Inhibitory Concentration (MIC100) value of test chemical in green algae (Cryptomonas sp.) in a 10 days. study on growth effect was determine to be 475.9 ± 10.3 mg/L. Thus considering CLP Criteria for aquatic classification of the substance, it is concluded that the test chemical does not exhibit toxicity to green algae (Cryptomonas sp).

Executive summary:

Summarized result for the toxicity of test chemical on the growth of algae were studied and reviewed. The details are as mention below:

To evaluate toxicity of test chemical on the growth of Dunaliella salina. Saltwater Dunaliella salina were used as a test organism which exposed for the 10 days of incubation. Serial concentrations of test chemical were supplemented into the modified medium for the culture of Dunaliella salina. The inocula, each containing 3 × 10(4) alga cells, were added to 10mL of the corresponding media and incubated in an oscillator shaker at a rate of 150 rpm under light irradiation of 81.04μmolm−2 s−1 and a 12 h/12 h light/dark cycle. Minimum Inhibitory Concentration (MIC100) value of test chemical in green algae (Dunaliella salina) in a 10 days. study on growth effect was determine to be 356.8 mg/L.Thus considering CLP Criteria for aquatic classification of the substance, it is concluded that test chemical does not exhibit toxicity to green algae (Dunaliella salina).

First study was supported by the second study from peer reviewed journal. In this study the effects of chemical on the growth and metabolite accumulation of Chlorella sp. were investigated to assess its possible application to the mass culture of the two diatoms in open environment, extensive systems. Test conducted under the static system for 10 days. brackish water Chlorella sp. maintain under the proper conditions of temperature and pH. Serial concentrations of test chemical were supplemented into the  f/2 medium for Chlorella sp. At concentrations >700 mg/l, the growth of Chlorella sp. was inhibited. Minimum Inhibitory Concentration (MIC100) of test chemical in green algae (Chlorella sp.) in a 10 days study on growth effect was observed to be 696.2 ± 9.4 mg/L. Thus considering CLP Criteria for aquatic classification of the substance, it is concluded that the test chemical does not exhibit toxicity to green algae (Chlorella sp.) and thus not classified.

Similarly in the third study aim of this study was to determine the effect of test chemical on the growth of Cryptomonas sp. Test conducted under the static system for the total exposure period of 10 days. Minimum Inhibitory Concentration (MIC100) value of test chemical in green algae (Cryptomonas sp.) in a 10 days. study on growth effect was determine to be 475.9 ± 10.3 mg/L. Thus considering CLP Criteria for aquatic classification of the substance, it is concluded that the test chemical does not exhibit toxicity to green algae (Cryptomonas sp) and thus not classified as per the classification criteria.

Thus based on the above data from various peer reviewed journals, chemical consider to be nontoxic and not classified as per the CLP classification criteria.

Description of key information

1: Minimum Inhibitory Concentration (MIC100) value of test chemical in green algae (Dunaliella salina) in a 10 days. study on growth effect was determine to be 356.8 mg/L.Thus considering CLP Criteria for aquatic classification of the substance, it is concluded that test chemical does not exhibit toxicity to green algae (Dunaliella salina).

2: Minimum Inhibitory Concentration (MIC100) of test chemical in green algae (Chlorella sp.) in a 10 days study on growth effect was observed to be 696.2 ± 9.4 mg/L.

3: Minimum Inhibitory Concentration (MIC100) value of test chemical in green algae (Cryptomonas sp.) in a 10 days. study on growth effect was determine to be 475.9 ± 10.3 mg/L. Thus considering CLP Criteria for aquatic classification of the substance, it is concluded that the test chemical does not exhibit toxicity to green algae (Cryptomonas sp).

Key value for chemical safety assessment

EC50 for freshwater algae:

356.8 mg/L

Additional information

Summarized result for the toxicity of test chemical and structurally and functionally similar read across chemicals on the growth of algae were studied and reviewed. The details are as mention below: 

 

To evaluate toxicity of test chemical on the growth of Dunaliella salina. Saltwater Dunaliella salina were used as a test organism which exposed for the 10 days of incubation. Serial concentrations of test chemical were supplemented into the modified medium for the culture of Dunaliella salina. The inocula, each containing 3 × 10(4) alga cells, were added to 10mL of the corresponding media and incubated in an oscillator shaker at a rate of 150 rpm under light irradiation of 81.04μmolm−2 s−1 and a 12 h/12 h light/dark cycle. Minimum Inhibitory Concentration (MIC100) value of test chemical in green algae (Dunaliella salina) in a 10 days. Study on growth effect was determine to be 356.8 mg/L. Thus considering CLP Criteria for aquatic classification of the substance, it is concluded that test chemical does not exhibit toxicity to green algae (Dunaliella salina).

 

 

First study was supported by the second study from peer reviewed journal. In this study the effects of chemical on the growth and metabolite accumulation of Chlorella sp. were investigated to assess its possible application to the mass culture of the two diatoms in open environment, extensive systems. Test conducted under the static system for 10 days. Brackish water Chlorella sp. maintain under the proper conditions of temperature and pH. Serial concentrations of test chemical were supplemented into the f/2 medium for Chlorella sp. At concentrations >700 mg/l, the growth of Chlorella sp. was inhibited. Minimum Inhibitory Concentration (MIC100) of test chemical in green algae (Chlorella sp.) in a 10 days study on growth effect was observed to be 696.2 ± 9.4 mg/L. Thus considering CLP Criteria for aquatic classification of the substance, it is concluded that the test chemical does not exhibit toxicity to green algae (Chlorella sp.) and thus not classified.

 

 

Similarly in the third study aim of this study was to determine the effect of test chemical on the growth of Cryptomonas sp. Test conducted under the static system for the total exposure period of 10 days. Minimum Inhibitory Concentration (MIC100) value of test chemical in green algae (Cryptomonas sp.) in a 10 days study on growth effect was determine to be 475.9 ± 10.3 mg/L. Thus considering CLP Criteria for aquatic classification of the substance, it is concluded that the test chemical does not exhibit toxicity to green algae (Cryptomonas sp) and thus not classified as per the classification criteria.

 

Thus based on the above data from various peer reviewed journals, chemical consider to be nontoxic and not classified as per the CLP classification criteria.