Interactions of Long-Chain Perfluorotelomer Alcohol and Perfluorinated Hydrocarbons with Model Decomposer Membranes

Perfluorinated hydrocarbons and their polar derivatives are produced annually in high quantities and find multiple industrial and technological applications due to their chemical and physical durability, significant hydro- and lipophobicity and excellent surface activity. Unfortunately, multiple perfluorinated compounds are recognized as persistent organic pollutants as they are completely nonbiodegradable and accumulate in soils and sediments. In our studies, we applied Langmuir monolayers formed by different structural phospholipids as models of soil bacteria and fungi membranes and investigated the effects exerted by long-chain perfluorinated pollutants, perfluorotelomer alcohol and two structurally different perfluorinated hydrocarbons, on the artificial membranes. Various mutually complemental methods such as surface pressure-mean molecular area isotherm registration, Brewster angle microscopy (BAM), and grazing incidence X-ray diffraction (GIXD) were applied. It turned out that the presence of the perfluorinated chemicals profoundly affected the phospholipid monolayers. The miscibility of the phospholipid with the perfluorotelomer alcohol depended strongly on the size and charge of the polar headgroup. Additionally, it was observed by BAM that the presence of the perfluorinated molecules significantly changed the texture of all the investigated phospholipid monolayers. On the basis of the BAM and GIXD results and other studies described in the scientific literature, we postulated that the perfluorinated hydrocarbons form an additional monolayer anchored on top of the phospholipid film. Our studies prove that both polar and nonpolar perfluorinated pollutants can be toxic to decomposer organisms and that their toxicity is strictly correlated with the phospholipid composition of the cellular membrane.