Chlorosulphuric acid

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

11-05-2018 to 14-05-2018

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

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:

no

Vehicle:

no

Details on test solutions:

The stock solution 100 mg/l was prepared by dissolving pale yellow liquid 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:
- 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:

Control: 8 changes to 7.7 during test

Nominal and measured concentrations:

0, 3.1, 6.2, 12.5, 25 and 50 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): 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: ErC50

Effect conc.:

23.2 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: 95 % CI was 15.2 - 35.6 mg/l

Results with reference substance (positive control):

- Results with reference substance valid
- ErC50: 0.77 mg/L (24 hours)

Reported statistics and error estimates:

ErC50 was calculated using non linear regression by the software Prism 4.0

Table: pH values

Sample concentration (mg/l)	3.1	6.2	12.5	25.0	50.0
Start of the test	7.6	7.2	6.9	6.0	3.5
End of the test	7.7	7.5	7.2	5.8	3.5

Control: 8.0 changes to 7.7 during the test

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 for 72 hrs, the ErC50 value was determine to be 23.2 mg/l.

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). Test was conducted according to the OECD guideline 201. The stock solution 100 mg/l was prepared by dissolving pale yellow liquid 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. Various concentrations 0, 3.1, 6.2, 12.5, 25 and 50 mg/l were used. 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 for 72 hrs, the ErC50 value was determine to be 23.2 mg/l. Based on this ErC50 value which indicates that the substance is likely to be hazardous to aquatic algae and can be consider to be classified as aquatic chronic 3 category as per the CLP classification criteria. Tested substance is an acid and that is why the higher concentration the lower pH. The optimum pH for algae is about 8.0. The highest two concentrations could be influence by the lower pH. Adjustment of pH could change sample property. Thus on the basis of acidic nature of chemical, we cannot consider as toxic to algae and thus not classified in any criteria.

Description of key information

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). Test was conducted according to the OECD guideline 201. The stock solution 100 mg/l was prepared by dissolving pale yellow liquid 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. Various concentrations 0, 3.1, 6.2, 12.5, 25 and 50 mg/l were used. 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 for 72 hrs, the ErC50 value was determine to be 23.2 mg/l. Based on this ErC50 value which indicates that the substance is likely to be hazardous to aquatic algae and can be consider to be classified as aquatic chronic 3 category as per the CLP classification criteria. Tested substance is an acid and that is why the higher concentration the lower pH. The optimum pH for algae is about 8.0. The highest two concentrations could be influence by the lower pH. Adjustment of pH could change sample property. Thus on the basis of acidic nature of chemical, we cannot consider as toxic to algae and thus not classified in any criteria.

Key value for chemical safety assessment

EC50 for freshwater algae:

23.2 mg/L

Additional information

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). Test was conducted according to the OECD guideline 201. The stock solution 100 mg/l was prepared by dissolving pale yellow liquid 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. Various concentrations 0, 3.1, 6.2, 12.5, 25 and 50 mg/l were used. 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 for 72 hrs, the ErC50 value was determine to be 23.2 mg/l. Based on this ErC50 value which indicates that the substance is likely to be hazardous to aquatic algae and can be consider to be classified as aquatic chronic 3 category as per the CLP classification criteria. Tested substance is an acid and that is why the higher concentration the lower pH. The optimum pH for algae is about 8.0. The highest two concentrations could be influence by the lower pH. Adjustment of pH could change sample property. Thus on the basis of acidic nature of chemical, we cannot consider as toxic to algae and thus not classified in any criteria.