Lipid-water partition coefficients and correlations with uptakes by algae of organic compounds

In view of the scarcity of the lipid-water partition coefficients (K-tw) for organic compounds, the logK(tw) values for many environmental contaminants were measured using ultra-pure triolein as the model lipid. Classes of compounds studied include alkyl benzenes, halogenated benzenes, short-chain chlorinated hydrocarbons, polycyclic aromatic hydrocarbons, polychlorinated biphenyls, and organochlorine pesticides. In addition to logK(tw) determination, the uptakes of these compounds from water by a dry algal species were measured to evaluate the lipid effect on the algal uptake. The measured logK(tw) are closely related to their respective logK(ow) (octanol-water), with logK(ow) = 1.9 to 6.5. A significant difference is observed between the present and early measured logK(tw) for compounds with logK(ow) which is attributed to the presence and absence of a triolein microemulsion in water affecting the solute partitioning. The observed lipid-normalized algae-water distribution coefficients (logK(aw/lipid)) are virtually identical to the respective logK(tw) values, which manifests the dominant lipid-partition effect of the compounds with algae. (C) 2014 Elsevier B.V. All rights reserved.