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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:
supporting study
Reliability:
4 (not assignable)
Rationale for reliability incl. deficiencies:
secondary literature
Justification for type of information:
Data is from secondary sources
Qualifier:
according to
Guideline:
OECD Guideline 201 (Alga, Growth Inhibition Test)
Version / remarks:
No data available
Deviations:
not specified
Principles of method if other than guideline:
Detection of the effect of D & C Red no. 7 on the growth and biomass rate of Selenastrum capricornutum by following standard OECD guideline.
GLP compliance:
not specified
Specific details on test material used for the study:
- Name of test material (as cited in study report): 2-Naphthalenecarboxylic acid, 3-hydroxy-4-[(4-methyl-2-sulfophenyl)azo]-, calcium salt- Molecular formula (if other than submission substance): C18H14N2O6S.Ca- Molecular weight (if other than submission substance): 424.445 g/mole- Smiles notation (if other than submission substance): c12c(c(c(C(=O)[O-])cc1cccc2)O)\N=N\c1c(cc(C)cc1)S(=O)(=O)[O-].[Ca+2]- InChl (if other than submission substance): 1S/C18H14N2O6S.Ca/c1-10-6-7-14(15(8-10)27(24,25)26)19-20-16-12-5-3-2-4-11(12)9-13(17(16)21)18(22)23;/h2-9,21H,1H3, (H,22,23)(H,24,25,26);/q;+2/p-2/b20-19+;- Substance type: Organic - Physical state: Solid - Analytical purity: 87%- Impurities (identity and concentrations): 13%
Analytical monitoring:
no
Details on sampling:
No data available
Vehicle:
not specified
Details on test solutions:
No data available
Test organisms (species):
other: Selenastrum capricornutum
Details on test organisms:
TEST ORGANISM- Common name: Green algae- Strain: ATCC 22662
Test type:
static
Water media type:
freshwater
Total exposure duration:
72 h
Remarks on exposure duration:
No data available
Post exposure observation period:
No data available
Hardness:
No data available
Test temperature:
No data available
pH:
No data available
Dissolved oxygen:
No data available
Salinity:
No data available
Conductivity:
No data available
Nominal and measured concentrations:
13 nominal concentrations (1.0-1000 mg/l).
Details on test conditions:
- Type (delete if not applicable): open / closed: Open system
Reference substance (positive control):
not specified
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
190 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
biomass
Remarks on result:
other: Nontoxic
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
5.8 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
biomass
Remarks on result:
other: No effect was observed(p < 0.05)
Details on results:
No data available
Results with reference substance (positive control):
No data available
Reported statistics and error estimates:
No data available
Conclusions:
Based on the biomass inhibition of Selenastrum capricornutum ATCC 22662 by the chemical calcium 3-hydroxy-4-[(4-methyl-2-sulfonatophenyl) diazenyl]-2-naphthoate (D & C Red no. 7) for 72hrs, the NOEC was 5.8 mg/l, and the EC50 was 190 mg/l.
Executive summary:

Detection of the effect of test chemical on the growth of Selenastrum capricornutum ATCC 22662 by following standard 202 OECD guideline. The test was performed in static system by following the OECD guideline. Selenastrum capricornutum ATCC 22662 exposed with the chemical for 72hrs. Based on the biomass inhibition of Selenastrum capricornutum ATCC 22662 by the chemical calcium 3-hydroxy-4-[(4-methyl-2-sulfonatophenyl) diazenyl]-2-naphthoate for 72hrs, the NOEC was 5.8 mg/l, and the EC50 was 190 mg/l. Based on the EC50 value it was concluded that the chemical calcium 3-hydroxy-4-[(4-methyl-2-sulfonatophenyl) diazenyl]-2-naphthoate was nontoxic and can be consider to be not classified as toxic as per the CLP classification criteria.

Description of key information

Detection of the effect of test chemical on the growth of Selenastrum capricornutum ATCC 22662 by following standard 202 OECD guideline. The test was performed in static system by following the OECD guideline. Selenastrum capricornutum ATCC 22662 exposed with the chemical for 72hrs. Based on the biomass inhibition of Selenastrum capricornutum ATCC 22662 by the chemical calcium 3-hydroxy-4-[(4-methyl-2-sulfonatophenyl) diazenyl]-2-naphthoate for 72hrs, the NOEC was 5.8 mg/l, and the EC50 was 190 mg/l. Based on the EC50 value it was concluded that the chemical calcium 3-hydroxy-4-[(4-methyl-2-sulfonatophenyl) diazenyl]-2-naphthoate was nontoxic and can be consider to be not classified as toxic as per the CLP classification criteria.

Key value for chemical safety assessment

EC50 for freshwater algae:
190 mg/L

Additional information

Based on the experimental data for the target compound calcium 3-hydroxy-4-[(4-methyl-2-sulfonatophenyl) diazenyl]-2-naphthoate (CAS no. 5281-04-9) and experimental studies for supporting weight of evidence studies for its structural and functional similarity were reviewed for the toxicity on the algae end point which are summarized as below: 

 

In the first key study for the target chemical from secondary sources toxicity was measured. Detection of the effect of D & C Red no. 7 on the growth of Selenastrum capricornutum ATCC 22662 by following standard 202 OECD guideline. The test was performed in static system by following the OECD guideline. Selenastrum capricornutum ATCC 22662 exposed with the chemical for 72hrs. Based on the biomass inhibition of Selenastrum capricornutum ATCC 22662 by the chemical calcium 3-hydroxy-4-[(4-methyl-2-sulfonatophenyl) diazenyl]-2-naphthoate for 72hrs, the NOEC was 5.8 mg/l, and the EC50 was 190 mg/l. Based on the EC50 value it was concluded that the chemical calcium 3-hydroxy-4-[(4-methyl-2-sulfonatophenyl) diazenyl]-2-naphthoate was nontoxic and can be consider to be not classified as toxic as per the CLP classification criteria.

 

First study was supported by the second experimental study for the structural and functional similarity read across chemical (from experimental study 2016). Freshwater algal growth inhibition test was carried out on Desmodesmus subspicatus with the test substance according to OECD Guideline 201. The stock solution 200 mg/L was prepared by dissolving dark blue powder in OECD growth medium. The stock solution was kept 5 min in ultrasonic bath. Test solutions of required concentrations were prepared by mixing the stock solution of the test sample with OECD growth medium and inoculum culture. Tested at the concentrations 0, 0, 12.5, 25, 50, 100 and 200 mg/L. Effects on the growth rate of the organism were studied. The median effective concentration (ErC50) for the test substance, in Desmodesmus subspicatus was determined to be 276.1 mg/L. Based on this ErC50 value and after comparing with CLP criteria for aquatic classification of the substance it is concluded that the substance does not exhibit toxicity to aquatic algae (Desmodesmus subspicatus).

 

Similarly in the third study for the structurally similar read across chemical toxicity was measured (from experimental study 2016). Freshwater algal growth inhibition test was carried out on Desmodesmus subspicatus with the substance according to OECD Guideline 201. The stock solution 130 mg/L was prepared by dissolving dark red 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. The test substance was dissolved in OECD growth medium and tested at the concentrations 0, 2.6, 5.6, 12.0, 27.0, 59.0 and 130 mg/L. Effects on the growth rate of the organism were studied. The median effective concentration (ErC50) for the test substance, in Desmodesmus subspicatus was determined to be 265.1 mg/L. Based on this ErC50 value and after comparing with CLP criteria for aquatic classification of the substance it is concluded that the substance does not exhibit toxicity to aquatic algae (Desmodesmus subspicatus).

 

Based on the above experimental data chemical calcium 3-hydroxy-4-[(4-methyl-2-sulfonatophenyl) diazenyl]-2-naphthoate (CAS no. 5281-04-9) was consider as nontoxic and not classified as per the CLP classification criteria.