9-(2-carboxyphenyl)-3,6-bis(diethylamino)xanthylium acetate

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:

weight of evidence

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)

GLP compliance:

no

Analytical monitoring:

no

Details on test solutions:

The stock solution 100mg/L was prepared by dissolving red -violet 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

ACCLIMATION - No data available

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Test temperature:

23±2°C

pH:

Test at highest concentration: 6.2 (changed to 7.8 during tests)
Control: 8.1 (changed to 7.7 during test)

Nominal and measured concentrations:

0, 5, 10 ,20 , 40 and 80 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: 50 ml Glass vessel
- Type: 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.:

45.7 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: 95 % CI: 36.7 - 56.8

Results with reference substance (positive control):

- Results with reference substance valid
- ErC50: 0.77 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 for 72h the EC50 was determine to be 45.7 mg/l.

Executive summary:

Aim of this study was to evaluate the nature of test chemical when comes in contact with the test organism Desmodesmus subspicatus (previous name: Scenedesmus subspicatus). The stock solution 100mg/L was prepared by dissolving red -violet 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 concentration (0, 5, 10, 20, 40 and 80 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.

 

The median effective concentration (EC50) for the test substance in algae was determined to be 45.7 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 thus can be classified as aquatic chronic 3 category as per the CLP classification criteria.

Description of key information

The median effective concentration (EC50) for the test substance in algae was determined to be 45.7 mg/L on the basis of growth rate inhibition effects in a 72 hour study. Based on the EC50 value, which indicates that the test substance is likely to be hazardous to aquatic algae and thus can be classified as aquatic chronic 3 category as per the CLP classification criteria.

Key value for chemical safety assessment

EC50 for freshwater algae:

45.7 mg/L

Additional information

Based on the experimental data for the target as well as read-across analogues which were functionally and structurally similar to the target chemical, toxicity of test chemical was determined on the basis of growth inhibition of aquatic algae. The studies are summarized as below:

Aim of this study was to evaluate the nature of test chemical when comes in contact with the test organism Desmodesmus subspicatus (previous name: Scenedesmus subspicatus). The stock solution 100mg/L was prepared by dissolving red -violet 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 concentration (0, 5, 10, 20, 40 and 80 mg/L) were used.

Along 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 determined after an exposure period of 72 hrs.

The median effective concentration (EC50) for the test substance in algae was determined to be 45.7 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 thus can be classified as aquatic chronic 3 category as per the CLP classification criteria.

 

Further the first study was supported by second and third study as follows.

 

Aim of the second 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 pinkish red powder in OECD growth medium. Various concentration used were 0, 2.5, 5, 10, 20 and 40 mg/L.

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 determined after an exposure period of 72 hrs. The median effective concentration (EC50) for the test substance, in algae was determined to be 13.4 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 acute/ chronic 3 category as per the CLP classification criteria.

Another study was conducted to determine the toxicity of test chemical on freshwater algae,Scenedesmus subspicatus for 72h. The test was conducted by following the similar guidelines as mentioned in OECD 201. Overall, cell growth in controls was found to be increased up to16 folds. After 72h of exposure the EC50 valuewas determined to be 11mg/L. Whereas, EC10 and EC90 were also determined with values 3mg/L and 42mg/L respectively.

Thus, based on the EC50 value, the test chemical is classified under the category aquatic chronic 3.

Hence, from the above values the test chemical is likely to be hazardous to aquatic algae and can be classified as aquatic chronic 3 category as per the CLP classification criteria.