2,2-dimethylbutane

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:

key study

Study period:

Not applicable, calculated value

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:

A discussion and report on the read across strategy is given as an attachment in IUCLID Section 13. 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 abou 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 (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:

The data were calculated by a computer model

Specific details on test material used for the study:

All details on input parameters are included in Section 13 of this dossier.

Analytical monitoring:

not required

Details on sampling:

No data

Vehicle:

no

Details on test solutions:

No data

Test organisms (species):

Daphnia magna

Details on test organisms:

No data

Test type:

other: QSAR modeled data

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Post exposure observation period:

No data

Hardness:

No data

Test temperature:

No data

pH:

No data

Dissolved oxygen:

No data

Salinity:

No data

Nominal and measured concentrations:

No data

Details on test conditions:

No adta

Reference substance (positive control):

not required

Duration:

48 h

Dose descriptor:

EL50

Effect conc.:

3.68 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: QSAR

Remarks:

Based on QSAR prediction

Details on results:

No data

Results with reference substance (positive control):

No data

Reported statistics and error estimates:

No data

Validity criteria fulfilled:

yes

Conclusions:

The estimated freshwater invertebrate acute EL50 value is 3.68 mg/L based on mobility

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 (K_MW) that describe the partitioning of the hydrocarbons between the water and organism.

The estimated freshwater invertebrate acute EL50 value is 3.68 mg/L based on mobility.

Description of key information

A QSAR prediction using Petrotox v3.06 predicted an acute LL50 for invertebrates of 3.68 mg/l, which is considered the key value for acute invertebrate toxicity.

 

This is supported by and experimental study on the read-across substance n-hexane which reported a 48-hr LC₅₀ for daphnia of 45 mmol/m³ (WAF)