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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
Study period:
16-09-2016 to 19-09-2016
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Justification for type of information:
Experimental test result performed using standard test guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 201 (Alga, Growth Inhibition Test)
Principles of method if other than guideline:
Aim of this study was to evaluate the nature of chemical when comes in contact with the test organism. Test was conducted according to the OECD guideline 201.
GLP compliance:
no
Analytical monitoring:
not specified
Vehicle:
not specified
Details on test solutions:
The stock solution 100 mg/l was prepared by dissolving yellow- green powder in OECD growth medium . 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
- Common name: fresh algae
- 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

ACCLIMATION - No data available
Test type:
static
Water media type:
freshwater
Limit test:
yes
Total exposure duration:
72 h
Test temperature:
23±2°C
pH:
sample: pH = 7.6 change to pH = 7.5 during the test,
control: pH = 8.2 changed to pH 7.8 during the test
Nominal and measured concentrations:
100 mg/l
Details on test conditions:
TEST SYSTEM
- Test vessel: 50 ml Glass vessel
- Sample volume: 7.5 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: microscope with counting chamber Cyrus I or 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: I%
Effect conc.:
7 other: %
Nominal / measured:
meas. (not specified)
Conc. based on:
test mat.
Basis for effect:
growth rate
Remarks on result:
other: 7.0 % inhibition observed at 100 mg/l
Results with reference substance (positive control):
- Results with reference substance valid
- EC50: 0.69 mg/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 chemical the inhibition percentage 7.0 % as observed to be .
Executive summary:

Aim of this study was to evaluate the nature of chemical test chemical when comes in contact with the test organism Desmodesmus subspicatus (previous name: Scenedesmus subspicatus). The stock solution 100 mg/l was prepared by dissolving yellow- green powder in OECD growth medium . Test solutions of required concentrations were prepared by mixing the stock solution of the test sample with OECD growth medium and inoculum culture.

With the test substance one positive control Potassium dichromate (K2Cr2O7) was also run simultaneously. After the exposure of chemical, effect concentration EC50 was calculated using nonlinear regression by the software Prism 4.0. Effect on the growth of algae was determine after an exposure period of 72 hrs.

The median inhibition percentage (I%) for the test substance , in algae was determined to be 7.0% at concentration 100 mg/l on the basis of growth rate inhibition effects in a 72 hour study. Based on the inhibition percentage , which indicates that the substance is likely to be non-hazardous to aquatic algae and cannot classified as per the CLP classification criteria.

Description of key information

Toxicity to aquatic algae and cyanobacteria:

Aim of this study was to evaluate the nature of chemical test chemical when comes in contact with the test organism Desmodesmus subspicatus (previous name: Scenedesmus subspicatus).The stock solution 100 mg/l was prepared by dissolving yellow- green powder in OECD growth medium . Test solutions of required concentrations were prepared by mixing the stock solution of the test sample with OECD growth medium and inoculum culture.

With the test substance one positive control Potassium dichromate (K2Cr2O7) was also run simultaneously. After the exposure of chemical, effect concentration EC50 was calculated using nonlinear regression by the software Prism 4.0. Effect on the growth of algae was determine after an exposure period of 72 hrs.

The median inhibition percentage (I%) for the test substance , in algae was determined to be 7.0% at concentration 100 mg/l on the basis of growth rate inhibition effects in a 72 hour study. Based on the inhibition percentage , which indicates that the substance is likely to be non-hazardous to aquatic algae and cannot classified as per the CLP classification criteria.

Key value for chemical safety assessment

EC50 for freshwater algae:
100 mg/L

Additional information

Toxicity to aquatic algae and cyanobacteria:

Toxicity to aquatic algae and cyanobacteria was evlauted based on experimental data and data from peer reviewed journal , aim of this study was to evaluate the nature of chemical test chemical when comes in contact with the test organism Desmodesmus subspicatus (previous name: Scenedesmus subspicatus).The stock solution 100 mg/l was prepared by dissolving yellow- green powder in OECD growth medium . Test solutions of required concentrations were prepared by mixing the stock solution of the test sample with OECD growth medium and inoculum culture.

With the test substance one positive control Potassium dichromate (K2Cr2O7) was also run simultaneously. After the exposure of chemical, effect concentration EC50 was calculated using nonlinear regression by the software Prism 4.0. Effect on the growth of algae was determine after an exposure period of 72 hrs.

The median inhibition percentage (I%) for the test substance , in algae was determined to be 7.0% at concentration 100 mg/l on the basis of growth rate inhibition effects in a 72 hour study. Based on the inhibition percentage , which indicates that the substance is likely to be non-hazardous to aquatic algae and cannot classified as per the CLP classification criteria.

.

According to peer revieved journal,to study the efffects of test material on aquatic algae test was carried for 96 hr.The study was performed under static conditions in a fresh water system. The concern levels identified by use of the SAR technique are expressed ad HIGH, MODERATE, LOW.Dyes with aquatic toxicity values below 1mg/l received a HIGH concern rating; those with toxicity values ranging from 1-100mg/l received a MODERATE concern rating and those with toxicity values greater than 100mg/l received a LOW concern rating.The median Effective concentration (EC50) value for test materialon Green algae in a 96 hour study was determined to be 20 mg/L.Since the EC50 for the test chemical lies between 1 – 100mg/l, it falls in MODERATE category in the aquatic toxicity ratings.Thus based on the EC50 value, it can be concluded that the substance can be classified as aquatic chronic category 3.

As the relibility of study report is high and the test has been carried out according to OECD guideline , test substance is not considered to have toxic effect on aquatic algae , and hence test substance is not classified as per CLP criteria.

As the relibility of study report is high and the test has been carried out according to OECD guideline , test substance is not considered to have toxic effect on aquatic algae , and hence test substance is not classified as per CLP criteria.