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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:
(Q)SAR
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: This summary has a reliability of 2 because the results are estimated using a computer model that is appropriate for use with this petroleum substance.
Justification for type of information:
Petrotox is a well-documented and peer reviewed model that is widely used across the petrochemicals industry. This substance fits within the criteria of the model and there are no reservations about the validity of the model runs. It is expected that this data is reliable with restrictions.
Qualifier:
no guideline followed
Principles of method if other than guideline:
The aquatic toxicity was estimated by a QSAR, the PETROTOX computer model. This model combines a partitioning model used to calculate the aqueous concentration of hydrocarbon components with the Target Lipid Model used to calculate acute and chronic toxicity of non-polar narcotic chemicals. PETROTOX computes toxicity based on the summation of the aqueous-phase concentrations of hydrocarbon block(s) that represent a hydrocarbon substance and membrane-water partition coefficients (KMW) that describe the partitioning of the hydrocarbons between the water and organism.
GLP compliance:
no
Remarks:
The data were calculated by a computer model
Analytical monitoring:
not required
Test organisms (species):
Pseudokirchneriella subcapitata (previous names: Raphidocelis subcapitata, Selenastrum capricornutum)
Water media type:
freshwater
Limit test:
no
Total exposure duration:
72 h
Key result
Duration:
72 h
Dose descriptor:
EL50
Effect conc.:
0.79 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Remarks on result:
other: QSAR calculation
Executive summary:

The aquatic toxicity was estimated using the PETROTOX computer model, which combines a partitioning model (used to calculate the aqueous concentration of hydrocarbon components as a function of substance loading) with the Target Lipid Model (used to calculate acute and chronic toxicity of non-polar narcotic chemicals). PETROTOX computes toxicity based on the summation of the aqueous phase concentrations of hydrocarbon block(s) that represent a petroleum substance and membrane water partition coefficients (KMW) that describe the partitioning of the hydrocarbons between the water and organism.

 

The estimated 72-hr EL50 value for growth rate of Pseudokirschneriella subcapitata is 0.79 mg/L.

Description of key information

The aquatic toxicity was estimated using the PETROTOX computer model, which combines a partitioning model (used to calculate the aqueous concentration of hydrocarbon components as a function of substance loading) with the Target Lipid Model (used to calculate acute and chronic toxicity of non-polar narcotic chemicals). PETROTOX computes toxicity based on the summation of the aqueous phase concentrations of hydrocarbon block(s) that represent a petroleum substance and membrane water partition coefficients (KMW) that describe the partitioning of the hydrocarbons between the water and organism.

 

The estimated 72-hr EL50 value for growth rate of Pseudokirschneriella subcapitata is 0.79 mg/L.

Supporting data on Toluene and Ethylbenzene, two constituents in Category J were used to support the QSAR prediction. An experimental 72 -hour EC50 of 4.6 mg/l was reported for ethylbenzene and a 3 -hour EC50 of 134 mg/l for toluene was reported.

Key value for chemical safety assessment

EC50 for freshwater algae:
0.79 mg/L

Additional information