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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:
18.09.2018 to 21.09.2018
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:
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 sodium naphthalene-1-sulfonate when comes in contact with the test organism. Test was conducted according to the OECD guideline 201.
GLP compliance:
not specified
Specific details on test material used for the study:
- Name of test material: sodium naphthalene-1-sulfonate
- Molecular formula: C10H7NaO3S
- Molecular weight: 230.218 g/mol
- Smiles notation: c12c(S(=O)(=O)[O-])cccc1cccc2.[Na+]
- InChl: 1S/C10H8O3S.Na/c11-14(12,13)10-7-3-5-8-4-1-2-6-9(8)10;/h1-7H,(H,11,12,13);/q;+1/p-1
- Substance type: Organic
- Physical state: Solid

Analytical monitoring:
not specified
Vehicle:
not specified
Details on test solutions:
The solution 100 mg/l was prepared by dissolving white powder in OECD growth medium.
Test organisms (species):
Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)
Details on test organisms:
TEST ORGANISM
- Common name:
- 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
- Acclimation period:
- Culturing media and conditions (same as test or not):
- Any deformed or abnormal cells observed:
Test type:
static
Water media type:
freshwater
Limit test:
yes
Total exposure duration:
72 h
Test temperature:
23±2°C
pH:
Test at highest concentration: 8 changes to 7.7
Control: 8.1 changes to 7.7
Nominal and measured concentrations:
100 mg/l
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): 6

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: IC
Effect conc.:
100 mg/L
Nominal / measured:
meas. (not specified)
Conc. based on:
test mat.
Basis for effect:
growth rate
Remarks on result:
other: 0.5 % inhibition were observed at 100 mg/l.
Results with reference substance (positive control):
- Results with reference substance valid
- EC50: 0.77mg/L (24 hours)
Reported statistics and error estimates:
The differences in means of control and sample were estimated by the t-test for independent groups at a 95 % confidence level, all individual replicates were used (STATISTICA CZ – data analysis software system, version 9.0, StatSoft, Inc.). Statistically significant differences are for p < 0.05.
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 sodium naphthalene-1-sulfonate, only 0.5 % inhibition were observed at 100 mg/l.
Executive summary:

Aim of this study was to evaluate the nature of test chemical sodium naphthalene-1-sulfonate when comes in contact with the test organism Desmodesmus subspicatus (previous name: Scenedesmus subspicatus). Test was conducted according to the OECD guideline 201. Limit test performed at 100 mg/l. The solution 100 mg/l was prepared by dissolving white powder in OECD growth medium. 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. Based on the growth rate inhibition of algae Desmodesmus subspicatus (previous name: Scenedesmus subspicatus) due to the exposure of chemical sodium naphthalene-1-sulfonate, only 0.5 % inhibition were observed at 100 mg/l. Based on the effects on the algae it was consider that the IC50 was greater then 100 mg/l. Thus chemical consider to be non-hazardous to aquatic algae and cannot be classified as per the CLP classification criteria.

Description of key information

Aim of this study was to evaluate the nature of test chemical sodium naphthalene-1-sulfonate when comes in contact with the test organism Desmodesmus subspicatus (previous name: Scenedesmus subspicatus). Test was conducted according to the OECD guideline 201. Limit test performed at 100 mg/l. The solution 100 mg/l was prepared by dissolving white powder in OECD growth medium. 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. Based on the growth rate inhibition of algae Desmodesmus subspicatus (previous name: Scenedesmus subspicatus) due to the exposure of chemical sodium naphthalene-1-sulfonate, only 0.5 % inhibition were observed at 100 mg/l. Based on the effects on the algae it was consider that the IC50 was greater then 100 mg/l. Thus chemical consider to be non-hazardous to aquatic algae and cannot be classified as per the CLP classification criteria.

Key value for chemical safety assessment

Additional information

Summarized result for the toxicity of test chemical sodium naphthalene-1-sulfonate CAS No. 130 -14 -3, on the growth of algae was studied on the basis of two experimental studies are mention below:

In the first experimental study toxicity was measured. Aim of this study was to evaluate the nature of test chemical sodium naphthalene-1-sulfonate when comes in contact with the test organism Desmodesmus subspicatus (previous name: Scenedesmus subspicatus). Test was conducted according to the OECD guideline 201. Limit test performed at 100 mg/l. The solution 100 mg/l was prepared by dissolving white powder in OECD growth medium. 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. Based on the growth rate inhibition of algae Desmodesmus subspicatus (previous name: Scenedesmus subspicatus) due to the exposure of chemical sodium naphthalene-1-sulfonate, only 0.5 % inhibition were observed at 100 mg/l. Based on the effects on the algae it was consider that the IC50 was greater then 100 mg/l. Thus chemical consider to be non-hazardous to aquatic algae and cannot be classified as per the CLP classification criteria.

Similarly in the second study the effect of test substance sodium naphthalene-1-sulfonate CAS No. 130 -14 -3 was studied on the growth of fresh water green alga Chlorella vulgaris. The study was conducted following OECD guideline 201- Alga growth inhibition test. The test concentration chosen for the study were 6.25mg/L,12.5 mg/L,25 mg/L,50 mg/L,100 mg/L,200 mg/L. The test concentrations were prepared using stock solution of the test substance using de-ionized water. The green alga was exposed to the test concentration for a period of 72 hours to observe average specific growth rate and % growth inhibition under the effect of test substance. EC50 calculated from equation through probit analysis was observed to be 33.47mg/L.

As the both studies occurs on two different species thus the effect of test chemical was varies. Both the studies performed according to the OECD guideline. As the other studies indicates that the chemical was nontoxic, thus overall studies consider to be nontoxic and not classified as per the CLP classification criteria.