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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:
results derived from a valid (Q)SAR model and falling into its applicability domain, with adequate and reliable documentation / justification
Justification for type of 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 hydrocarbon substance and membrane-water partitioning coefficients (KMW) that describe the partitioning of the hydrocarbons between the water and organism.
Qualifier:
no guideline followed
Principles of method if other than guideline:
The aquatic toxicity was estimated by a QSAR, the Petrotox computer model (v 3.06). 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:
(Q)SAR
Analytical monitoring:
not required
Vehicle:
no
Test organisms (species):
Tetrahymena pyriformis
Test type:
other: (Q)SAR
Water media type:
freshwater
Limit test:
no
Total exposure duration:
48 h
Key result
Duration:
48 h
Dose descriptor:
other: LL50
Effect conc.:
43.7 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth inhibition
Key result
Duration:
48 h
Dose descriptor:
NOEC
Effect conc.:
2.19 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth inhibition
Validity criteria fulfilled:
yes
Conclusions:
Toxicity to microorganisms has been estimated using Petrotox. The estimated protozoan, Tetrahymena pyriformis, 48 hr LL50 value for this substance is 43.70 mg/L based on growth inhibition. The estimated NOEC value is 2.19 mg/L based on growth inhibition.
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 hydrocarbon substance and membrane-water partitioning coefficients (KMW) that describe the partitioning of the hydrocarbons between the water and organism.

Toxicity to microorganisms has been estimated using Petrotox.  The estimated protozoan, Tetrahymena pyriformis, 48 hr LL50 value for this substance is 43.70 mg/L based on growth inhibition. The estimated NOEC value is 2.19 mg/L based on growth inhibition.

Description of key information

Toxicity to microorganisms has been estimated using Petrotox. The estimated protozoan, Tetrahymena pyriformis, 48 hr LL50 value for Hydrocarbons, C6-C10 (even numbered), n-alkanes, isoalkanes, >5% n-hexane is 43.70 mg/L based on growth inhibition. The estimated NOEC value is 2.19 mg/L based on growth inhibition.

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 teh summation of the aqueous-phase concentrations of hydrocarbon block(s) that represent a hydrocarbon substance and membrane-water partitioning coefficients (KMW) that describe the partitioning of the hydrocarbons between the water and organism.

Key value for chemical safety assessment

EC50 for microorganisms:
43.7 mg/L
EC10 or NOEC for microorganisms:
2.19 mg/L

Additional information