2-tert-butylhydroquinone

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

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:

This study was perfomred to understand the extent of toxicity caused by test chemical to fresh water algae, for the period of 72 hrs.

GLP compliance:

no

Analytical monitoring:

no

Vehicle:

no

Details on test solutions:

The stock solution 100 mg/L was prepared by dissolving white 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:
- 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

Remarks on exposure duration:

72 ±1 h

Test temperature:

23±2°C

pH:

Test at highest concentration: 8.1
Control: 7.8

Nominal and measured concentrations:

nominal concentration 1, 1.8, 3.1, 5.6, 10, and 20.0 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 per replcate
- 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.:

9.3 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: 95 % CI 8.5-10.1 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

Validity criteria fulfilled:

yes

Conclusions:

Based on the growth inhibition rate of algae Desmodesmus subspicatus (previous name: Scenedesmus subspicatus) due to the exposure of test chemical, the ErC50 was determine to be 9.3 mg/L

Executive summary:

Aim of this study was to evaluate the toxic nature of 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. 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 ranging from 1.0 to 20.0,along with one positive control Potassium dichromate (K2Cr2O7). After the exposure of chemical, median effective 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 effective concentration (ErC50) for the test substance to algae was determined to be 9.3 mg/L on the basis of growth rate inhibition effects in a 72 hour study. Based on the EC50 value, which indicates that the substance is likely to be hazardous to aquatic algae and can be classified as aquatic chronic 2, category as per the CLP classification criteria.

Description of key information

Aim of this study was to evaluate the toxic nature of 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. 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 ranging from 1.0 to 20.0,along with one positive control Potassium dichromate (K2Cr2O7). After the exposure of chemical, median effective 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 effective concentration (ErC50) for the test substance to algae was determined to be 9.3 mg/L on the basis of growth rate inhibition effects in a 72 hour study. Based on the EC50 value, which indicates that the substance is likely to be hazardous to aquatic algae and can be classified as aquatic chronic 2, category as per the CLP classification criteria.

Key value for chemical safety assessment

EC50 for freshwater algae:

9.3 mg/L

Additional information

Aim of this study was to evaluate the toxic nature of 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. 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 ranging from 1.0 to 20.0,along with one positive control Potassium dichromate (K2Cr2O7). After the exposure of chemical, median effective 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 effective concentration (ErC50) for the test substance to algae was determined to be 9.3 mg/L on the basis of growth rate inhibition effects in a 72 hour study. Based on the EC50 value, which indicates that the substance is likely to be hazardous to aquatic algae and can be classified as aquatic chronic 2, category as per the CLP classification criteria.