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Toxicity to aquatic algae and cyanobacteria

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Endpoint:
toxicity to aquatic algae and cyanobacteria
Type of information:
experimental study
Adequacy of study:
weight of evidence
Study period:
not reported
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
study well documented, meets generally accepted scientific principles, acceptable for assessment
Reason / purpose:
other: read-across target
Related information:
Composition 1
Reference:
Composition 0
Qualifier:
no guideline followed
Principles of method if other than guideline:
Study to investigate the effect of growth inhibition on the algae Dunaliella salina, Cryptomonas sp. and Chlorella sp. following exposure to potassium iodide.
GLP compliance:
not specified
Test material information:
Composition 1
Analytical monitoring:
not specified
Vehicle:
not specified
Test organisms (species):
Chlorella sp.
Test type:
not specified
Water media type:
not specified
Total exposure duration:
10 d
Test temperature:
25 °C
Dissolved oxygen:
above 45 % saturation
Details on test conditions:
TEST SYSTEM
- Fill volume: 10 mL
- Aeration: inocula were incubated in an oscillator shaker at a rate of 150 rpm
- Initial cells density: 3 × 10^4 alga cells

TEST MEDIUM
- Standard medium used: f/2 medium

OTHER TEST CONDITIONS
- Photoperiod: 12 h/12 h light/dark cycle
- Light intensity and quality: light irradiation of 81.04 μmolm^−2 s^−1

EFFECT PARAMETERS MEASURED
The growth of algae was determined by counting the number of cells using a haemacytometer The minimum concentration of potassium iodide that inhibited growth was designated as MIC100.

ANALYSIS
Cell density was determined by a haemacytometer. Biomass was determined as cell dry weight.
Reference substance (positive control):
not specified
Key result
Duration:
10 d
Dose descriptor:
other: MIC100
Effect conc.:
696.2 mg/L
Nominal / measured:
meas. (not specified)
Conc. based on:
test mat.
Basis for effect:
growth rate
Reported statistics and error estimates:
The data collected in the experiments were processed using SPSS 10.0 software. The assumptions of analysis of variance were considered to be statistically significant at p < 0.05.
Validity criteria fulfilled:
not specified
Conclusions:
The Minimum Inhibitory Concentration (MIC100) value of potassium iodide in algae (Chlorella sp.) over a 10 day study period, was determined to be 696.2 ± 9.4 mg/L. It is therefore concluded that potassium iodide does not exhibit toxicity to algae (Chlorella sp.).
Executive summary:

The effect of growth inhibition on the algae Chlorella sp. was investigated following a 10-day exposure to potassium iodide.

Under the conditions of the study, the Minimum Inhibitory Concentration (MIC100) value of potassium iodide in algae (Chlorella sp.)  over a 10 day study period, was determined to be 696.2 ± 9.4 mg/L. It is therefore concluded that potassium iodide does not exhibit toxicity to algae (Chlorella sp.).

Endpoint:
toxicity to aquatic algae and cyanobacteria
Type of information:
experimental study
Adequacy of study:
weight of evidence
Study period:
not reported
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
study well documented, meets generally accepted scientific principles, acceptable for assessment
Reason / purpose:
other: read-across target
Related information:
Composition 1
Reference:
Composition 0
Qualifier:
no guideline followed
Principles of method if other than guideline:
Study to investigate the effect of growth inhibition on the algae Dunaliella salina, Cryptomonas sp. and Chlorella sp. following exposure to potassium iodide.
GLP compliance:
not specified
Test material information:
Composition 1
Analytical monitoring:
not specified
Vehicle:
not specified
Test organisms (species):
other: Cryptomonas sp.
Test type:
not specified
Water media type:
not specified
Total exposure duration:
10 d
Test temperature:
25 °C
Dissolved oxygen:
above 45 % saturation
Details on test conditions:
TEST SYSTEM
- Fill volume: 10 mL
- Aeration: inocula were incubated in an oscillator shaker at a rate of 150 rpm
- Initial cells density: 3 × 10^4 alga cells

TEST MEDIUM
- Standard medium used: f/2 medium

OTHER TEST CONDITIONS
- Photoperiod: 12 h/12 h light/dark cycle
- Light intensity and quality: light irradiation of 81.04 μmolm^−2 s^−1

EFFECT PARAMETERS MEASURED
The growth of algae was determined by counting the number of cells using a haemacytometer The minimum concentration of potassium iodide that inhibited growth was designated as MIC100.

ANALYSIS
Cell density was determined by a haemacytometer. Biomass was determined as cell dry weight.
Reference substance (positive control):
not specified
Key result
Duration:
10 d
Dose descriptor:
other: MIC100
Effect conc.:
475.9 mg/L
Nominal / measured:
meas. (not specified)
Conc. based on:
test mat.
Basis for effect:
growth rate
Reported statistics and error estimates:
The data collected in the experiments were processed using SPSS 10.0 software. The assumptions of analysis of variance were considered to be statistically significant at p < 0.05.
Validity criteria fulfilled:
not specified
Conclusions:
The Minimum Inhibitory Concentration (MIC100) value of potassium iodide in algae (Cryptomonas sp.) over a 10 day study period, was determined to be 475.9 ± 10.3 mg/L. It is therefore concluded that potassium iodide does not exhibit toxicity to algae (Cryptomonas sp.).
Executive summary:

The effect of growth inhibition on the algae Cryptomonas sp. was investigated following a 10-day exposure to potassium iodide.

Under the conditions of the study, the Minimum Inhibitory Concentration (MIC100) value of potassium iodide in algae (Cryptomonas sp.)  over a 10 day study period, was determined to be 475.9 ± 10.3 mg/L. It is therefore concluded that potassium iodide does not exhibit toxicity to algae (Cryptomonas sp.).

Endpoint:
toxicity to aquatic algae and cyanobacteria
Type of information:
experimental study
Adequacy of study:
weight of evidence
Study period:
not reported
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
study well documented, meets generally accepted scientific principles, acceptable for assessment
Reason / purpose:
other: read-across target
Related information:
Composition 1
Reference:
Composition 0
Qualifier:
no guideline followed
Principles of method if other than guideline:
Study to investigate the effect of growth inhibition on the algae Dunaliella salina, Cryptomonas sp. and Chlorella sp. following exposure to potassium iodide.
GLP compliance:
not specified
Test material information:
Composition 1
Analytical monitoring:
not specified
Vehicle:
not specified
Test organisms (species):
Dunaliella salina
Test type:
not specified
Water media type:
not specified
Total exposure duration:
10 d
Test temperature:
25°C
Dissolved oxygen:
above 45 % saturation
Details on test conditions:
TEST SYSTEM
- Fill volume: 10 mL
- Aeration: inocula were incubated in an oscillator shaker at a rate of 150 rpm
- Initial cells density: 3 × 10^4 alga cells

TEST MEDIUM
- Standard medium used: modified Johnson’s medium

OTHER TEST CONDITIONS
- Photoperiod: 12 h/12 h light/dark cycle
- Light intensity and quality: light irradiation of 81.04 μmolm^−2 s^−1

EFFECT PARAMETERS MEASURED
The growth of algae was determined by counting the number of cells using a haemacytometer The minimum concentration of potassium iodide that inhibited growth was designated as MIC100.

ANALYSIS
Cell density was determined by a haemacytometer. Biomass was determined as cell dry weight.
Reference substance (positive control):
not specified
Key result
Duration:
10 d
Dose descriptor:
other: MIC100
Effect conc.:
356.8 mg/L
Nominal / measured:
meas. (not specified)
Conc. based on:
test mat.
Basis for effect:
growth rate
Reported statistics and error estimates:
The data collected in the experiments were processed using SPSS 10.0 software. The assumptions of analysis of variance were considered to be statistically significant at p < 0.05.
Validity criteria fulfilled:
not specified
Conclusions:
The Minimum Inhibitory Concentration (MIC100) value of potassium iodide in algae (Dunaliella salina) over a 10 day study period, was determined to be 356.8 ± 14.6 mg/L. It is therefore concluded that potassium iodide does not exhibit toxicity to algae (Dunaliella salina).
Executive summary:

The effect of growth inhibition on the algae Dunaliella salina, was investigated following a 10-day exposure to potassium iodide.

Under the conditions of the study, the Minimum Inhibitory Concentration (MIC100) value of potassium iodide in algae (Dunaliella salina)  over a 10 day study period, was determined to be 356.8 ± 14.6 mg/L. It is therefore concluded that potassium iodide does not exhibit toxicity to algae (Dunaliella salina).

Endpoint:
toxicity to aquatic algae and cyanobacteria
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
supporting study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Study conducted on read-across material
Justification for type of information:
The read-across chemical is potassium iodide (CAS No 7681-11-0) which belongs to the same family/category of inorganic iodine compounds as the target chemical sodium iodate. It is understood that iodide oxidises to iodate and that the anion is the fragment of the substance that drives toxicity. Furthermore potassium and sodium cations are ubiquitous in the environment and are not expected to cause an effect at dosing concentrations.
Reason / purpose:
read-across source
Related information:
Composition 1
Test material information:
Composition 1
Duration:
10 d
Dose descriptor:
other: MIC100
Effect conc.:
696.2 mg/L
Nominal / measured:
meas. (not specified)
Conc. based on:
test mat.
Basis for effect:
growth rate
Endpoint:
toxicity to aquatic algae and cyanobacteria
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
supporting study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Study conducted on read-across material
Justification for type of information:
The read-across chemical is potassium iodide (CAS No 7681-11-0) which belongs to the same family/category of inorganic iodine compounds as the target chemical sodium iodate. It is understood that iodide oxidises to iodate and that the anion is the fragment of the substance that drives toxicity. Furthermore potassium and sodium cations are ubiquitous in the environment and are not expected to cause an effect at dosing concentrations.
Reason / purpose:
read-across source
Related information:
Composition 1
Test material information:
Composition 1
Duration:
10 d
Dose descriptor:
other: MIC100
Effect conc.:
475.9 mg/L
Nominal / measured:
meas. (not specified)
Conc. based on:
test mat.
Basis for effect:
growth rate
Endpoint:
toxicity to aquatic algae and cyanobacteria
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
supporting study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Study conducted on read-across material
Justification for type of information:
The read-across chemical is potassium iodide (CAS No 7681-11-0) which belongs to the same family/category of inorganic iodine compounds as the target chemical sodium iodate. It is understood that iodide oxidises to iodate and that the anion is the fragment of the substance that drives toxicity. Furthermore potassium and sodium cations are ubiquitous in the environment and are not expected to cause an effect at dosing concentrations.
Reason / purpose:
read-across source
Related information:
Composition 1
Test material information:
Composition 1
Duration:
10 d
Dose descriptor:
other: MIC100
Effect conc.:
356.8 mg/L
Nominal / measured:
meas. (not specified)
Conc. based on:
test mat.
Basis for effect:
growth rate

Description of key information

The Minimum Inhibitory Concentration (MIC100) value of potassium iodide in the algae Dunaliella salina, Cryptomonas sp. and Chlorella sp., over a 10 day study period, was determined to be 356.8 ± 14.6, 475.9 ± 10.3, and 696.2 ± 9.4 mg/L, respectively. It is therefore concluded that potassium iodide does not exhibit toxicity to the algae Dunaliella salina, Cryptomonas sp. and Chlorella sp.

Key value for chemical safety assessment

Additional information

The effect of growth inhibition on the algae Cryptomonas sp. was investigated following a 10-day exposure to potassium iodide.

Under the conditions of the study, the Minimum Inhibitory Concentration (MIC100) value of potassium iodide in the algae Dunaliella salina, Cryptomonas sp. and Chlorella sp., over a 10 day study period, was determined to be 356.8 ± 14.6, 475.9 ± 10.3, and 696.2 ± 9.4 mg/L, respectively. It is therefore concluded that potassium iodide does not exhibit toxicity to the algae Dunaliella salina, Cryptomonas sp. and Chlorella sp.