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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:
22-05-2017 to 25-05-2017
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Experimental test result performed using standard test guideline
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 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 (as cited in study report): 4',5'-dibromo-3',6'-dihydroxyspiro[isobenzofuran-1(3H),9'-[9H]xanthene]-3-one- Molecular formula: C20 H10 Br2 O5- Molecular weight: 490.102 g/mol- Smiles notation: C12(c3c(Oc4c1ccc(c4Br)O)c(c(O)cc3)Br)c1c(cccc1)C(O2)=O-InChl: 1S/C20H10Br2O5/c21-15-13(23)7-5-11-17(15)26-18-12(6-8-14(24)16(18)22)20(11)10-4-2-1-3-9(10)19(25)27-20/h1-8,23-24H- Substance type: Organic- Physical state: Solid
Analytical monitoring:
not specified
Vehicle:
not specified
Details on test solutions:
The stock solution 100.0 g/l was prepared by dissolving pink powder in OECD growth medium. Test solutions of required concentrationas 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 availableACCLIMATION - 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 testControl + DMSO: 8 changes to 7.7 during testOptimum pH for test chemical: 8
Nominal and measured concentrations:
0, 6, 12, 25, 50 and 100 mg/l oncentration were used
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): 3GROWTH MEDIUM- Standard medium used: yesOTHER TEST CONDITIONS- Adjustment of pH: No- Photoperiod: Continuous- Light intensity and quality: 6000-8000 lxEFFECT 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.:
50.9 mg/L
Nominal / measured:
meas. (not specified)
Conc. based on:
test mat.
Basis for effect:
growth rate
Remarks on result:
other: 95 % CI 41.1-58.7 mg/l
Results with reference substance (positive control):
- Results with reference substance valid- EC50: 0.75 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 test chemical, the ErC50 was determine to be 50.9 mg/l.
Executive summary:

Aim of this study was to evaluate the nature of chemical test chemical 4',5'-dibromo-3',6'-dihydroxyspiro[isobenzofuran-1(3H),9'-[9H]xanthene]-3-one 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 100.0 g/l was prepared by dissolving pink powder in OECD growth medium. Test solutions of required concentrationas were prepared by mixing the stock solution of the test sample with OECD growth medium and inoculum culture and tested at 0, 6, 12, 25, 50 and 100 mg/l oncentration. 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 test chemical, the ErC50 was determine to be 50.9 mg/l. Based on the ErC50 value, it was concluded that the substance 4',5'-dibromo-3',6'-dihydroxyspiro[isobenzofuran-1(3H),9'-[9H]xanthene]-3-one

is likely to be hazardous to aquatic algae and can be be classified as aquatic chronic 3 category as per the CLP criteria.

Description of key information

Aim of this study was to evaluate the nature of chemical test chemical 4',5'-dibromo-3',6'-dihydroxyspiro[isobenzofuran-1(3H),9'-[9H]xanthene]-3-one 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 100.0 g/l was prepared by dissolving pink powder in OECD growth medium. Test solutions of required concentrationas were prepared by mixing the stock solution of the test sample with OECD growth medium and inoculum culture and tested at 0, 6, 12, 25, 50 and 100 mg/l oncentration. 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 test chemical, the ErC50 was determine to be 50.9 mg/l. Based on the ErC50 value, it was concluded that the substance 4',5'-dibromo-3',6'-dihydroxyspiro[isobenzofuran-1(3H),9'-[9H]xanthene]-3-one

is likely to be hazardous to aquatic algae and can be be classified as aquatic chronic 3 category as per the CLP criteria.

Key value for chemical safety assessment

EC50 for freshwater algae:
50.9 mg/L

Additional information

Aim of this study was to evaluate the nature of chemical test chemical 4',5'-dibromo-3',6'-dihydroxyspiro[isobenzofuran-1(3H),9'-[9H]xanthene]-3-one 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 100.0 g/l was prepared by dissolving pink powder in OECD growth medium. Test solutions of required concentrationas were prepared by mixing the stock solution of the test sample with OECD growth medium and inoculum culture and tested at 0, 6, 12, 25, 50 and 100 mg/l oncentration. 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 test chemical, the ErC50 was determine to be 50.9 mg/l. Based on the ErC50 value, it was concluded that the substance 4',5'-dibromo-3',6'-dihydroxyspiro[isobenzofuran-1(3H),9'-[9H]xanthene]-3-one

is likely to be hazardous to aquatic algae and can be be classified as aquatic chronic 3 category as per the CLP criteria.