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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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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 read across substances
Justification for type of information:
Data for the target chemical is summarized based on the structurally similar read across chemicals
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 mentioned below
Principles of method if other than guideline:
WoE report is based on three toxicity to microorganism studies as-
WoE 2., WoE 3 and WoE 4.
GLP compliance:
not specified
Analytical monitoring:
no
Remarks:
WoE 2 and WoE 3: not specified and WoE 4: no
Vehicle:
not specified
Test organisms (species):
other: WoE 2: Microcystis aeruginosa, WoE 3 and WoE 4: Chlorella vulgaris
Details on test organisms:
WoE 2:
TEST ORGANISM
- Common name: green algae
- Strain: FACHB 315

WoE 3:
TEST ORGANISM
- Common name: green algae
- Strain: A-23
- Method of cultivation: The culture was centrifuged, the harvested cells washed with distilled water and resuspended in medium without nitrogen.

WoE 4:
TEST ORGANISM
- Common name: green algae
Test type:
static
Water media type:
freshwater
Total exposure duration:
120 h
Remarks on exposure duration:
WoE 2: 96 hrs and WoE 3 & WoE 4: 120 hrs
Test temperature:
WoE 2: 25°C
WoE 3 and 4: 26°C

pH:
WoE 2: 8.3
WoE 3: 7.0
WoE 4: no data available
Details on test conditions:
WoE 2: no data available

WoE 3:
TEST SYSTEM
- Aeration: Test culture was aerated with air containing 3% CO2.

GROWTH MEDIUM
- Standard medium used: Modified Prat's mineral medium was used as a test medium. Composition of the medium includes KH2PO4-0.135g, MgSO4.7H2O-0.5g, FeSO4.7H2O-0.003g, Sodium Citrate-0.006g, micronutrients solution-1ml, H2O-1000ml, respectively.

OTHER TEST CONDITIONS
- Light intensity: 6000 lux

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : After a period of 120 hrs, number of cells, percentage of living cells, average cells size and pH was measured.
Key result
Duration:
96 h
Dose descriptor:
EC50
Effect conc.:
199.79 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Remarks on result:
other: WoE 2: 95% C. I. = 153.574 to 259.969 mg/l
Duration:
120 h
Dose descriptor:
other: ErC50
Effect conc.:
1 300 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Remarks on result:
other: WoE 3
Duration:
120 h
Dose descriptor:
other: LC50
Effect conc.:
5 080 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other: mortality
Remarks on result:
other: WoE 3
Duration:
120 h
Dose descriptor:
IC50
Effect conc.:
330 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Remarks on result:
other: WoE 4
Validity criteria fulfilled:
not specified
Conclusions:
On the basis of the experimental studies of the comparatively similar read across chemical and applying the weight of evidence approach, the 96 EC50 and 120 hr EC50/LC50/IC50 value of the test chemical on test organism can be expected to be 199.79 mg/l and in the range of 330 to 5080 mg/l, respectively.
Executive summary:

Data available for the comparatively similar read across chemicals has been reviewed to determine the toxic effect of the test chemical on aquatic algae. The studies are as mentioned below:

An acute toxicity test was conducted for 96 hrs for assessing the effect of test chemical on green algae. Microcystis aeruginosa FACHB 315 (green algae) was used as a test organism. The study was performed taking cells from an exponential growth phase culture in a static system at a temperature of 25°C and pH 8.3, respectively. On the basis of effect of test chemical on decrease in growth rate of the test organism, the 96 hr ErC50 value was determined to be 199.79 mg/l (95% C. I. = 153.574 to 259.969 mg/l).

Another acute toxicity test was conducted for 120 hrs for assessing the effect of test chemical on green algae.Chlorella vulgarisA-23 (green algae) was used as a test organism. Study was performed in a static system. Modified Prat's mineral medium was used as a test medium. Composition of the medium includes KH2PO4-0.135g, MgSO4.7H2O-0.5g, FeSO4.7H2O-0.003g, Sodium Citrate-0.006g, micronutrients solution-1ml, H2O-1000ml, respectively. The culture was centrifuged, the harvested cells washed with distilled water and resuspended in medium without nitrogen. Test culture was aerated with air containing 3% CO2. 200ml aliquots were distributed into culture vessels containing appropriate amounts of test chemical as a nitrogen source. These test vessels were incubated for 120 hrs (5 days) under test conditions i.e, at a temperature of 26°C, pH 7.0 with light intensity of 6000 lux. After an exposure period of 120 hrs, number of cells, percentage of living cells, average cells size and pH was measured. On the basis of the effect on growth rate and mortality of the test organism, the 120 hr ErC50 and LC50 was determined to be 1300 mg/l and 5080 mg/l.

For the test chemical, toxicity to aquatic algae study was conducted for 120 hrs for assessing the effect of test chemical. Chlorella vulgaris(green algae) was used as a test organism. Study was performed in a static system at a temperature of 26°C. On the basis of the effect on growth rate of the test organism, the 120 hr IC50 value was determined to be 330 mg/l.

On the basis of the experimental studies of the structurally and functionally similar read across chemical and applying the weight of evidence approach, the 96 EC50 and 120 hr EC50/LC50/IC50 value of the test chemical on test organism can be expected to be 199.79 mg/l and in the range of 330 to 5080 mg/l, respectively. Thus, based on these values, test chemical was considered as non-toxic to aquatic algae and hence, considered to be ‘not classified’ as per the CLP classification criteria. 

Description of key information

On the basis of the experimental studies of the comparatively similar read across chemical and applying the weight of evidence approach, the 96 EC50 and 120 hr EC50/LC50/IC50 value of the test chemical on test organism can be expected to be 199.79 mg/l and in the range of 330 to 5080 mg/l, respectively

Key value for chemical safety assessment

EC50 for freshwater algae:
199.79 mg/L

Additional information

Data available for the comparatively similar read across chemicals has been reviewed to determine the toxic effect of the test chemical on aquatic algae. The studies are as mentioned below:

 

An acute toxicity test was conducted for 96 hrs for assessing the effect of test chemical on green algae. Microcystis aeruginosa FACHB 315 (green algae) was used as a test organism. The study was performed taking cells from an exponential growth phase culture in a static system at a temperature of 25°C and pH 8.3, respectively. On the basis of effect of test chemical on decrease in growth rate of the test organism, the 96 hr ErC50 value was determined to be 199.79 mg/l (95% C. I. = 153.574 to 259.969 mg/l).

 

Another acute toxicity test was conducted for 120 hrs for assessing the effect of test chemical on green algae. Chlorella vulgaris A-23 (green algae) was used as a test organism. Study was performed in a static system. Modified Prat's mineral medium was used as a test medium. Composition of the medium includes KH2PO4-0.135g, MgSO4.7H2O-0.5g, FeSO4.7H2O-0.003g, Sodium Citrate-0.006g, micronutrients solution-1ml, H2O-1000ml, respectively. The culture was centrifuged, the harvested cells washed with distilled water and resuspended in medium without nitrogen. Test culture was aerated with air containing 3% CO2. 200ml aliquots were distributed into culture vessels containing appropriate amounts of test chemical as a nitrogen source. These test vessels were incubated for 120 hrs (5 days) under test conditions i.e, at a temperature of 26°C, pH 7.0 with light intensity of 6000 lux. After an exposure period of 120 hrs, number of cells, percentage of living cells, average cells size and pH was measured. On the basis of the effect on growth rate and mortality of the test organism, the 120 hr ErC50 and LC50 was determined to be 1300 mg/l and 5080 mg/l.

 

For the test chemical, toxicity to aquatic algae study was conducted for 120 hrs for assessing the effect of test chemical. Chlorella vulgaris(green algae) was used as a test organism. Study was performed in a static system at a temperature of 26°C. On the basis of the effect on growth rate of the test organism, the 120 hr IC50 value was determined to be 330 mg/l.

 

On the basis of the experimental studies of the structurally and functionally similar read across chemical and applying the weight of evidence approach, the 96 EC50 and 120 hr EC50/LC50/IC50 value of the test chemical on test organism can be expected to be 199.79 mg/l and in the range of 330 to 5080 mg/l, respectively. Thus, based on these values, test chemical was considered as non-toxic to aquatic algae and hence, considered to be ‘not classified’ as per the CLP classification criteria.