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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:
calculation (if not (Q)SAR)
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Data is from computational model developed by USEPA
Justification for type of information:
Data is from computational model developed by USEPA
Qualifier:
according to
Guideline:
other: Modeling database
Principles of method if other than guideline:
Estimation of 96 hr EC50 value of test chemical by modelling Database - ECOSAR v.1.11. The ECOSAR Class Program is a computerized version of the ECOSAR analysis procedures as currently practiced by the Office of Pollution Prevention and Toxics (OPPT).  It has been developed within the regulatory constraints of the Toxic Substances Control Act (TSCA).  It is a pragmatic approach to SAR. The structure-activity relationships (SARs) presented in this program are used to predict the aquatic toxicity of chemicals based on their similarity of structure to chemicals for which the aquatic toxicity has been previously measured.  Most SAR calculations in the ECOSAR Class Program are based upon the octanol/water partition coefficient (Kow).  Various surfactant SAR calculations are based upon the average length of carbon chains or the number of ethoxylate units.
GLP compliance:
not specified
Specific details on test material used for the study:
- Name of test material (IUPAC name): (2S)-1,3,4,5,6,7-hexahydro-1,1,5,5-tetramethyl-2H-2,4a-methanonaphthalene
- IUPAC name: (2S)-1,3,4,5,6,7-hexahydro-1,1,5,5-tetramethyl-2H-2,4a-methanonaphthalene
- Moleuclar formula: C15H24
- Molecular weight: 204.3546 g/mol
- Substance type: Organic
- Smiles: CC1(C)CCC=C2C(C)(C)[C@H]3CC[C@@]12C3
- Inchi: 1S/C15H24/c1-13(2)8-5-6-12-14(3,4)11-7-9-15(12,13)10-11/h6,11H,5,7-10H2,1-4H3/t11-,15-/m0/s1
- Physical state: liquid
Analytical monitoring:
not required
Vehicle:
not specified
Test organisms (species):
other: green algae
Test type:
static
Water media type:
freshwater
Total exposure duration:
96 h
Remarks on exposure duration:
Estimated data
Duration:
96 h
Dose descriptor:
EC50
Effect conc.:
0.172 mg/L
Nominal / measured:
estimated
Conc. based on:
test mat.
Basis for effect:
growth rate
Remarks on result:
other: Neutral Organics SAR (Baseline Toxicity)
Validity criteria fulfilled:
not specified
Conclusions:
The estimated EC50 values of test material for aquatic green algae after 96 hours was 0.172 mg/l on the basis of growth rate.
Executive summary:

The toxicity of the test substance to green algae is predicted using EPI Suite ECOSAR version 1.11. On the basis of effects observed in a static freshwater system during a 96 hr exposure, the effect concentration (EC50) for the substance is estimated to be 0.172 mg/L. Based on this value, it can be concluded that the test chemical can be considered as toxic to green algae at environmentally relevant concentrations and can be considered to be classified in aquatic acute 1 as per the CLP classification criteria.

 

Description of key information

Toxicity to aquatic algae and cyanobacteria:

The toxicity of the test substance to green algae is predicted using EPI Suite ECOSAR version 1.11. On the basis of effects observed in a static freshwater system during a 96 hr exposure, the effect concentration (EC50) for the substance is estimated to be0.172mg/L. Based on this value, it can be concluded that the test chemical can be considered as toxic to green algae at environmentally relevant concentrations and can be considered to be classified in aquatic acute 1 as per the CLP classification criteria.

 

Key value for chemical safety assessment

EC50 for freshwater algae:
0.172 mg/L

Additional information

Toxicity to aquatic algae and cyanobacteria:

Toxicity of test material on aquatic algae and cyanobacteria was evaluated using predicted and experimental data from authorative database:

The toxicity of the test substance to green algae is predicted using EPI Suite ECOSAR version 1.11. On the basis of effects observed in a static freshwater system during a 96 hr exposure, the effect concentration (EC50) for the substance is estimated to be0.172mg/L. Based on this value, it can be concluded that the test chemical can be considered as toxic to green algae at environmentally relevant concentrations and can be considered to be classified in aquatic acute 1 as per the CLP classification criteria.

 

1) Short term toxicity study for the test material was conducted on aquatic algae and cyanobacteria as per OECD Guideline 201 (Alga, Growth Inhibition Test). The EC50 effect concentartion for the test substance on aquatic algae was obswerved to be >0.16 mg/l , the NOEC was observed to be 0.16 mg/l. Based on the above effect concentration it can be concluded that test material is toxic to aquatic algae and can be classified as aquatic acute 1 as per CLP criteria.

2)Alga, Growth Inhibition Test was carried with Pseudokirchneriella subcapitata, 72 hours for test material according to OECD Guideline 201 (Alga, Growth Inhibition Test).

The study was conducted under static conditions with an initial cell density of 5089 cells/mL. With regard to the volatility of the test item glass flasks without headspace were used to reduce losses of test item. Seven concentrations were tested in a geometrical series with a dilution

factor of 3.16 (nominal): 0.00500 - 0.0158 - 0.0500 - 0.158 - 0.500 - 1.58 - 5.00 mg/L, corresponding to geometric mean measured test item concentrations of 0.00467 - 0.0153 -0.0445 - 0.153 - 0.405 - 1.36 - 4.39 mgIL. Effective concentration EC50 to 50% of Pseudokirchneriella subcapitata when exposed to test material, for 72h is 0.72 mg/L.

It can be concluded from the EC50 Intoxication value that the test material is toxic to the aquatic algae and can be considered as “Aquatic acute 1” as per the classification criteria for aquatic environment.