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Ecotoxicological information

Toxicity to microorganisms

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Reference
Endpoint:
activated sludge respiration inhibition testing
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):
activated sludge
Water media type:
freshwater
Limit test:
no
Key result
Duration:
3 h
Dose descriptor:
other: LL50
Effect conc.:
28.99 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
inhibition of total respiration
Remarks on result:
other: QSAR calculation
Conclusions:
The estimated 3-hr LL50 value for the respiration inhibition of activated sludge is 28.99 mg/L.
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 3-hr LL50 value for the respiration inhibition of activated sludge is 28.99 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 3-hr LL50 value for the respiration inhibition of activated sludge is 28.99 mg/L.

Supporting data on Toluene a constituents in Category J was used to support the QSAR prediction. An Experimental 24 -hour IC50s of 84 mg/L for toluene has been reported.

Key value for chemical safety assessment

EC50 for microorganisms:
28.99 mg/L

Additional information