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Ecotoxicological information

Short-term toxicity to fish

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Description of key information

The freshwater fish 96 hour LL50 value is 30.46  mg/l based on mortality

Key value for chemical safety assessment

Fresh water fish

Fresh water fish
Effect concentration:
30.46 mg/L

Additional 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.

This is supported by measured values, of which data were only available for n-pentane, which were then read across to the rest of the category. The study (ExxonMobilChemical 1997) was conducted according to OECD Guideline 203 (Fish, Acute Toxicity Test) with some minor deviations to minimise volatilisation of the substance. During testing a decrease of 80 % of n-pentane concentration was observed. Therefore LC50calculation was performed using the geometric mean of the measured concentrations in the fresh and used medium. A 95 % confidence limit was established. The 96 hour LC50was reported as 4.26 mg/l (95% C. I 3.60 - 5.04 mg/l).

The hydrocarbon block method has been used for environmental risk assessment (see REACH guidance, R7, app.13-1). Aquatic PNECs for hydrocarbon blocks have been derived using the HC5 statistical extrapolation method and the target lipid model using representative structures. See Product Library tab in PETRORISK spreadsheet attached to IUCLID Section 13. Given the large database of freshwater organisms included in the target lipid model, an assessment factor of one has been applied to the HC5.