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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:
experimental study
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Justification for type of information:
Experimental test result performed using standard OECD test guideline
Qualifier:
according to
Guideline:
OECD Guideline 201 (Alga, Growth Inhibition Test)
Principles of method if other than guideline:
Short term toxicity of test chemical to Desmodesmus subspicatus (previous name: Scenedesmus subspicatus) was performed according to the OECD Guideline 201 (Alga, Growth Inhibition Test) in a static system.
GLP compliance:
no
Analytical monitoring:
no
Vehicle:
yes
Remarks:
Acetone was used as a vehicle.
Details on test solutions:
The stock solution 10 g/l was prepared by dissolving white powder in acetone. Test solutions of required concentrations were prepared by mixing the stock solution of the test sample with OECD growth medium and inoculum culture.
Test organisms (species):
Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)
Details on test organisms:
TEST ORGANISM
- Strain: 86.81 SAG
- Source (laboratory, culture collection): Institute of botany of the ASCR
- Initial biomass concentration: 5x10(3) cells /ml
- Method of cultivation: No data available
Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
72 h
Remarks on exposure duration:
± 1 hr
Test temperature:
23±2°C
pH:
without adjustment
the sample at concentration 42 mg/l: pH 6.5 changed to pH = 5.3 during the test
control: pH = 8.0 changed to pH = 7.3 during the test
control + acetone: pH = 7.7 changed to pH = 7.3 during the test
Nominal and measured concentrations:
Nominal test chemical conc. used for the study were 0, 0, 5, 9, 16, 23 and 42 mg/l, respectively.
Details on test conditions:
TEST SYSTEM
- Test vessel: 50 ml Glass vessel
- Type (delete if not applicable): closed (with air permeable stopper)
- Sample volume: 15 ml
- Initial cells density: 5x10(3) cells/ml
- No. of vessels per concentration (replicates): 3

GROWTH MEDIUM
- Standard medium used: yes

OTHER TEST CONDITIONS
- Adjustment of pH: No
- Photoperiod: Continuous
- Light intensity and quality: 6000-8000 lx

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: electronic particle counter.
- Other: ErC50 was calculated using non-linear regression by the software Prism 4.0
Reference substance (positive control):
yes
Remarks:
Potassium dichromate (K2Cr2O7)
Key result
Duration:
72 h
Dose descriptor:
other: ErC50
Effect conc.:
92.6 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Remarks on result:
other: 95 % CI was 58 - 148 mg/l
Results with reference substance (positive control):
- Results with reference substance valid
- EC50: 0.77mg/L (24 hours)
Reported statistics and error estimates:
EC50 was calculated using non linear regression by the software Prism 4.0.
Validity criteria fulfilled:
yes
Conclusions:
Based on the growth rate inhibition of algae Desmodesmus subspicatus (previous name: Scenedesmus subspicatus) due to the exposure of test chemical, the 72hr effect concentration (ErC50%) value was determined to be 92.6 mg/l.
Executive summary:

An acute test was conducted for 48 hrs for assessing the effect of test chemical on Desmodesmus subspicatus. The test was performed in accordance to OECD Guideline 201 (Alga, Growth Inhibition Test). Desmodesmus subspicatus (previous name: Scenedesmus subspicatus) of strain 86.81 SAG obtained from Institute of botany of the ASCR with an initial biomass conc. 5x10(3) cells /ml was used as a test organism for the study. The solution 10 g/l was prepared by dissolving white powder in acetone. Test concentrations 10 mg/l was prepared by mixing the stock solution of the test sample with OECD growth medium. Nominal test chemical conc. used for the study were 0, 0, 5, 9, 16, 23 and 42 mg/l, respectively. Study was performed using Desmodesmus subspicatus as a test organism in a static fresh water system. Desmodesmus subspicatus were exposed to test chemical in 50 ml glass vessel in a volume of 15 ml of liquid solution containing both the chemical and media. The beakers were placed in a room at a temperature of 23±2°C with a continuous light intensity of 6000-8000 lx, respectively. Alongwith the test chemical, one positive control Potassium dichromate (K2Cr2O7) was also run simultaneously. Cell counting was carried out using electronic particle counter. ErC50 was calculated using non-linear regression by the software Prism 4.0. On the basis of the effect of test chemical on the growth rate of the test organism Desmodesmus subspicatus, the 72 hr effect concentration (ErC50%) value was determined to be 92.6 mg/l (95 % CI was 58 - 148 mg/l). Thus, based on the ErC50 value, test chemical can be considered as toxic to aquatic algae and thus can be considered to be classified in ‘aquatic chronic category 3’ as per CLP classification criteria.

Description of key information

An acute test was conducted for 48 hrs for assessing the effect of test chemical on Desmodesmus subspicatus (Experimental study report, 2018). The test was performed in accordance to OECD Guideline 201 (Alga, Growth Inhibition Test). Desmodesmus subspicatus (previous name: Scenedesmus subspicatus) of strain 86.81 SAG obtained from Institute of botany of the ASCR with an initial biomass conc. 5x10(3) cells /ml was used as a test organism for the study. The solution 10 g/l was prepared by dissolving white powder in acetone. Test concentrations 10 mg/l was prepared by mixing the stock solution of the test sample with OECD growth medium. Nominal test chemical conc. used for the study were 0, 0, 5, 9, 16, 23 and 42 mg/l, respectively. Study was performed using Desmodesmus subspicatus as a test organism in a static fresh water system. Desmodesmus subspicatus were exposed to test chemical in 50 ml glass vessel in a volume of 15 ml of liquid solution containing both the chemical and media. The beakers were placed in a room at a temperature of 23±2°C with a continuous light intensity of 6000-8000 lx, respectively. Alongwith the test chemical, one positive control Potassium dichromate (K2Cr2O7) was also run simultaneously. Cell counting was carried out using electronic particle counter. ErC50 was calculated using non-linear regression by the software Prism 4.0. On the basis of the effect of test chemical on the growth rate of the test organism Desmodesmus subspicatus, the 72 hr effect concentration (ErC50%) value was determined to be 92.6 mg/l (95 % CI was 58 - 148 mg/l). Thus, based on the ErC50 value, test chemical can be considered as toxic to aquatic algae and thus can be considered to be classified in ‘aquatic chronic category 3’ as per CLP classification criteria.

Key value for chemical safety assessment

EC50 for freshwater algae:
92.6 mg/L

Additional information

An acute test was conducted for 48 hrs for assessing the effect of test chemical on Desmodesmus subspicatus (Experimental study report, 2018). The test was performed in accordance to OECD Guideline 201 (Alga, Growth Inhibition Test). Desmodesmus subspicatus (previous name: Scenedesmus subspicatus) of strain 86.81 SAG obtained from Institute of botany of the ASCR with an initial biomass conc. 5x10(3) cells /ml was used as a test organism for the study. The solution 10 g/l was prepared by dissolving white powder in acetone. Test concentrations 10 mg/l was prepared by mixing the stock solution of the test sample with OECD growth medium. Nominal test chemical conc. used for the study were 0, 0, 5, 9, 16, 23 and 42 mg/l, respectively. Study was performed using Desmodesmus subspicatus as a test organism in a static fresh water system. Desmodesmus subspicatus were exposed to test chemical in 50 ml glass vessel in a volume of 15 ml of liquid solution containing both the chemical and media. The beakers were placed in a room at a temperature of 23±2°C with a continuous light intensity of 6000-8000 lx, respectively. Alongwith the test chemical, one positive control Potassium dichromate (K2Cr2O7) was also run simultaneously. Cell counting was carried out using electronic particle counter. ErC50 was calculated using non-linear regression by the software Prism 4.0. On the basis of the effect of test chemical on the growth rate of the test organism Desmodesmus subspicatus, the 72 hr effect concentration (ErC50%) value was determined to be 92.6 mg/l (95 % CI was 58 - 148 mg/l). Thus, based on the ErC50 value, test chemical can be considered as toxic to aquatic algae and thus can be considered to be classified in ‘aquatic chronic category 3’ as per CLP classification criteria.