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Physical & Chemical properties

Water solubility

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Description of key information

water solubility (whole substance): <0.1 m/l at 20±0.5°C (measured). 
water solubility (individual constituents): <1E-04 - 1.1E-03 mg/l at 20°C (QSAR)

Key value for chemical safety assessment

Additional information

The substance is a hydrocarbon UVCB and the constituent hydrocarbons will exhibit a wide range of water solubility. Standard tests for this endpoint are intended for single substances and are not appropriate for this complex substance as the composition of the total dissolved hydrocarbons will be different from the composition of the parent substance. However, this endpoint can be characterised using quantitative structure property relationships for representative hydrocarbon structures that comprise the hydrocarbon blocks used to assess the environmental risk of this substance with the PETRORISK model (see Product Library in PETRORISK spreadsheet attached in Section 13).

The "whole substance" water solubility of Hydrocarbons, C15 -C19, n-alkanes, isoalkanes, <2% aromatics was evaluated using a slow-stir method (Tarran 2015). The method was designed to be compatible with EU Method A.6 and OECD 105. Since the submission substance is a UVCB, the effect of initial loading rate was also evaluated during the definitive study using initial nominal loading rates of 100 mg/l and 10 mg/l to assess if the resulting aqueous concentration or the composition of the dissolved fraction were affected. The water solubility of Hydrocarbons, C15-C19, n-alkanes, isoalkanes, <2% aromatics was determined to be <0.1 m/l at 20±0.5°C in both the 100 mg/l and 10 mg/l loading rates.

As supporting information, the water solubility of each constituent has also been predicted using a separately validated QSAR estimation method. The prediction method uses a fragment method and water solubility decreases with increasing carbon number. The prediction domain covers carbon chain length in the range C2-C15 carbon atom, it is therefore expected that water solubility for longer chain length (i.e. greater than C15) compounds will be lower than the predicted value for C15 atom. Thus, the water solubility of the individual constituents are in the range <1E-04 - 1.1E-03 mg/l.