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Ecotoxicological information

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:
key study
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
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
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
Key result
Duration:
96 h
Dose descriptor:
EC50
Effect conc.:
4.821 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 for aquatic green algae after 96 hours was 4.821 mg/l on the basis of growth rate.
Executive summary:

The short-term toxicity of the test substance to green algae is predicted using EPI Suite ECOSAR version 1.10. 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 4.821 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 chronic category 2 as per the CLP classification criteria.

 

Description of key information

Toxicity to aquatic algae and cyanobacteria:

The short-term toxicity of the test substance to green algae is predicted using EPI Suite ECOSAR version 1.10. 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 4.821 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 chronic category 2 as per the CLP classification criteria.

 

Key value for chemical safety assessment

EC50 for freshwater algae:
4.821 mg/L

Additional information

Toxicity to aquatic algae and cyanobacteria:

The toxicity of test material to aquatic algae based on prediction along with data from authoritative data base for structurally and functionally similar read across substance.

The short-term toxicity of the test substance to green algae is predicted using EPI Suite ECOSAR version 1.10. 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 be4.821 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 chronic category 2 as per the CLP classification criteria.

The above prediction was further supported by data for functionally similar read across substance, the 72 h toxicity test was evaluated for aquatic alage and cyanobacteria. The effects were evaluated based on area under growth curve and growth rate of the green algae. The effect concentartion EC50 after 72 h was observed to be 8.9 based on the inhibiation of growth rate. Based on the EC50 value it can be ocncluded that test material has toxic effects on aquatic algae and can be classified as aquatic chcronic 2.

 The above data was further supported by data from another functionally similar read across substance,effect of test material was evaluated on green algae Selenastrum capricornutum for 72 h. The effect conccentration based on the growth rate was observed to be 2.6 mg/l . Based on the effect concentration it can be considered test substance has toxic effect on aquatic algae and can be classified as aquatic chronic 2.