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Diss Factsheets
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EC number: 201-142-8 | CAS number: 78-78-4
- Life Cycle description
- Uses advised against
- Endpoint summary
- Appearance / physical state / colour
- Melting point / freezing point
- Boiling point
- Density
- Particle size distribution (Granulometry)
- Vapour pressure
- Partition coefficient
- Water solubility
- Solubility in organic solvents / fat solubility
- Surface tension
- Flash point
- Auto flammability
- Flammability
- Explosiveness
- Oxidising properties
- Oxidation reduction potential
- Stability in organic solvents and identity of relevant degradation products
- Storage stability and reactivity towards container material
- Stability: thermal, sunlight, metals
- pH
- Dissociation constant
- Viscosity
- Additional physico-chemical information
- Additional physico-chemical properties of nanomaterials
- Nanomaterial agglomeration / aggregation
- Nanomaterial crystalline phase
- Nanomaterial crystallite and grain size
- Nanomaterial aspect ratio / shape
- Nanomaterial specific surface area
- Nanomaterial Zeta potential
- Nanomaterial surface chemistry
- Nanomaterial dustiness
- Nanomaterial porosity
- Nanomaterial pour density
- Nanomaterial photocatalytic activity
- Nanomaterial radical formation potential
- Nanomaterial catalytic activity
- Endpoint summary
- Stability
- Biodegradation
- Bioaccumulation
- Transport and distribution
- Environmental data
- Additional information on environmental fate and behaviour
- Ecotoxicological Summary
- Aquatic toxicity
- Endpoint summary
- Short-term toxicity to fish
- Long-term toxicity to fish
- Short-term toxicity to aquatic invertebrates
- Long-term toxicity to aquatic invertebrates
- Toxicity to aquatic algae and cyanobacteria
- Toxicity to aquatic plants other than algae
- Toxicity to microorganisms
- Endocrine disrupter testing in aquatic vertebrates – in vivo
- Toxicity to other aquatic organisms
- Sediment toxicity
- Terrestrial toxicity
- Biological effects monitoring
- Biotransformation and kinetics
- Additional ecotoxological information
- Toxicological Summary
- Toxicokinetics, metabolism and distribution
- Acute Toxicity
- Irritation / corrosion
- Sensitisation
- Repeated dose toxicity
- Genetic toxicity
- Carcinogenicity
- Toxicity to reproduction
- Specific investigations
- Exposure related observations in humans
- Toxic effects on livestock and pets
- Additional toxicological data
Short-term toxicity to aquatic invertebrates
Administrative data
Link to relevant study record(s)
- Endpoint:
- short-term toxicity to aquatic invertebrates
- 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 registered substance is a complex mixture whose constituents within the mixture have variable physicochemical properties. Therefore, a modeling framework is needed to account for the bioavailability of the constituents in the mixture, which was then used to predict the toxicity of the substance as a whole. A computer-based program, PETROTOX (v4.0), was used to calculate aquatic toxicity. The program is an extension of the three-phase partitioning (to calculate the partitioning of constituents in air, water, and non-aqueous phase liquid phases) and toxicity models used to predict the toxicity of complex substances, and incorporates the Target Lipid Model (TLM), which has been validated for applications to individual narcotic chemicals and mixtures. Composition information is entered as separate hydrocarbon blocks according to carbon number range and chemical classes, which comprise the substance.Representative constituents input to model located in the attachment "PETRORISK and PETROTOX block allocation" in Section 13.2 of IUCLID.
The TLM is a framework that relates toxicity to the physicochemical properties of a nonpolar organic constituent. The TLM is used to calculate the toxicity of the dissolved constituents to aquatic organisms. Toxicity of complex mixtures with common toxic modes of action is determined using toxic units (TU) that normalizes aqueous concentrations by their inherent toxicity. To compute a TU for each component, the estimated concentration, Cw, from the partitioning model is divided by the aqueous effect concentration (e.g., LC50 or NOEC). The individual toxic units are then summed to compute the toxicity of the mixture. The lethal or chronic loading is determined by iterating until a loading is determined that yields one TU.
The model contains a database of TLM parameters for more than 70 individual organisms including several fish, daphnid, and algal endpoints. The model contains a database of TLM parameters for more than 70 individual organisms including several fish, daphnid, and algal endpoints. The TLM framework was validated previously for acute and chronic aquatic toxicity endpoints. As such, modeled data are considered fit for purpose for classification and labelling and risk assessment. - Principles of method if other than guideline:
- The aquatic toxicity was estimated by a QSAR, the PETROTOX computer model (v 4.0). 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. For model description and justification of QSAR prediction: see field 'Justification for type of information'.
- Analytical monitoring:
- not required
- Test organisms (species):
- Daphnia magna
- Test type:
- other: QSAR
- Total exposure duration:
- 48 h
- Reference substance (positive control):
- not required
- Key result
- Duration:
- 48 h
- Dose descriptor:
- EL50
- Effect conc.:
- 59.9 mg/L
- Nominal / measured:
- estimated
- Conc. based on:
- other: QSAR prediction
- Basis for effect:
- mobility
- Remarks on result:
- other: QSAR predicted value
- Validity criteria fulfilled:
- yes
- Conclusions:
- The PETROTOX-estimated freshwater 48-h EL50 (Effect Loading Rate 50%) value for Daphnia magna is 59.9 mg/L based on mobility.
- Executive summary:
The aquatic toxicity was estimated using the PETROTOX computer model (v4.0), 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 nonpolar 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.
The PETROTOX-estimated freshwater 48-h EL50 (Effect Loading Rate 50%) value for Daphnia magna is 59.9 mg/L based on mobility.
Reference
Description of key information
The aquatic toxicity was estimated using the PETROTOX computer model (v4.0), 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 nonpolar 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.
Key value for chemical safety assessment
Additional information
Two studies for 2 -methylbutane and Pentane have been provided to support the QSAR data.
The 48-hour EC50 of 2-methylbutane to Daphnia magna has been reported to be 2.3mg/l (based on initial measured concentration ). However, the true EC50 value maybe higher since loss of the starting material was determine to be about 50% during the 48hr exposure period. The version of the study reviewed lacked the annex containing key details on the test conditions and therefore these could not be reviewed and generally validated against OECD criteria. However the study was selected as the key study in the EU risk assessment report for n-pentane and can be considered acceptable for assessment.
The 48-hour EC50 of Pentane to Daphnia magna has been reported to be 2.7 mg/l (based on initial measured concentration). However the true EC50 value may be higher since loss of the starting material was determined to be approximately 76 % during the 48 hr exposure period. The version of the study reviewed lacked the annex containing the key details on the test conditions and therefore these could not be reviewed and generally validated against the OECD criteria. However the study was selected as key study in the EU Risk assessment report for n-pentane and can be considered acceptable for assessment.
Information on Registered Substances comes from registration dossiers which have been assigned a registration number. The assignment of a registration number does however not guarantee that the information in the dossier is correct or that the dossier is compliant with Regulation (EC) No 1907/2006 (the REACH Regulation). This information has not been reviewed or verified by the Agency or any other authority. The content is subject to change without prior notice.
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