Thermal cracking oil from blends of rubber, fuel oils and paraffin waxes, steam distillation concentrate

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

(Q)SAR

Adequacy of study:

weight of evidence

Study period:

2021

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: An assessment was performed based on the predictive model PetroTox and for the other polar constituents, a combination of available data in literature and the use of QSAR modelling with ECOSAR (2.0)

Justification for type of information:

The aquatic toxicity was estimated by a QSAR, the Petrotox computer model (v.4). 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.

The other polar constituents of the substance were assessed using predicted toxicity data from ECOSAR 2.0 made available by the EPA. ECOSAR groups structurally similar organic chemicals with available experimental effect levels that are correlated with physicochemical properties in order to predict toxicity of new or untested industrial chemicals.

Qualifier:

no guideline followed

Principles of method if other than guideline:

The aquatic toxicity was estimated by a QSAR, the Petrotox computer model (v.4). 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.

The other polar constituents of the substance were assessed using predicted toxicity data from ECOSAR 2.0 made available by the EPA. ECOSAR groups structurally similar organic chemicals with available experimental effect levels that are correlated with physicochemical properties in order to predict toxicity of new or untested industrial chemicals.

Key result

Duration:

24 h

Dose descriptor:

LC50

Effect conc.:

1 090 mg/L

Conc. based on:

other: polar fraction

Basis for effect:

mortality

Key result

Duration:

24 h

Dose descriptor:

LC50

Effect conc.:

11.31 mg/L

Conc. based on:

other: hydrocarbon fraction

Basis for effect:

mortality

Details on results:

See attached expert assessment

Conclusions:

The predicted acute toxicity (LC50) of Thermal cracking oil from blends of rubber, fuel oils and paraffin waxes, steam distillation condensate to invertebrate is predicted to be 1090 mg/L
on the basis of polar fraction and 11.31 mg/L on the basis of hydrocarbon fraction. Hence, an
LL50 of 11.31 mg/L can be considered as the acute toxicity value of Thermal cracking oil from blends of rubber, fuel oils and paraffin waxes, steam distillation condensate in
invertebrates.

Executive summary:

Thermal cracking oil from blends of rubber, fuel oils and paraffin waxes, steam distillation condensate (EC 942-492-8) is a complex UVCB consisting of a combination of different hydrocarbon constituents with a range of different molecular weights and structures. As toxicity test data to invertebrates for the substance was not available, QSAR modelling was used to assess the toxicity to invertebrates for this substance.
For the hydrocarbon fraction the predictive model PetroTox, made available by CONCAWE was used, and for the other polar constituents, a combination of available data in literature and the use of QSAR modelling with ECOSAR (2.0) from the EPA was used.

The predicted acute toxicity (LC50) of Thermal cracking oil from blends of rubber, fuel oils and paraffin waxes, steam distillation condensate to invertebrate is predicted to be 1090 mg/L on the basis of polar fraction and 11.31 mg/L on the basis of hydrocarbon fraction. Hence, an LL50 of 11.31 mg/L can be considered as the acute toxicity value of Thermal cracking oil from blends of rubber, fuel oils and paraffin waxes, steam distillation condensate in invertebrates.

Description of key information

Thermal cracking oil from blends of rubber, fuel oils and paraffin waxes, steam distillation condensate (EC 942-492-8) is a complex UVCB consisting of a combination of different hydrocarbon constituents with a range of different molecular weights and structures. As toxicity test data to invertebrates for the substance was not available, QSAR modelling was used to assess the toxicity to algae (Pseudokirchneriella subcapitata) for this substance.
For the hydrocarbon fraction the predictive model PetroTox, made available by CONCAWE was used, and for the other polar constituents, a combination of available data in literature and the use of QSAR modelling with ECOSAR (2.0) from the EPA was used.

The predicted acute toxicity (LC50) of naphtha to invertebrate is predicted to be 1090 mg/L on the basis of polar fraction and 11.31 mg/L on the basis of hydrocarbon fraction. Hence, an LL50 of 11.31 mg/L can be considered as the acute toxicity value of naphtha in invertebrates.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

11.31 mg/L