Gottschling, Michael ; Zhou, Yanyue ; Schwabe, Ines ; Bui, Thu Quynh ; Oyen, Albert van ; Schebek, Liselotte ; Sakaguchi-Söder, Kaori
ed.: Baztan, J. (2018)
Comparison of one-time spiking, multiple spiking and dialysis tubing methods for the determination of plastic-water partition coefficient of one polycyclic hydrocarbons on microplastic.
MICRO 2018, Fate and Impact of Microplastics: Knowledge, Actions and Solutions. Lanzarote, Spain (19.11.2018-23.11.2018)
Conference or Workshop Item, Bibliographie

Abstract

Determination of sorption capacity of persistent organic pollutants (POPs) on microplastics (MPs) is essential to study ecological effect of POPs-loaded MPs in the aqueous environment. However, due to high octanol-water partition coefficients (Kow) as well as low water solubility, determination of sorption capacity of POPs on MPs in the laboratory is challenging. Here we present three methods to determine plastic-water partition coefficient of phenanthrene (Phen), one of polycyclic aromatic hydrocarbons (PAHs), on low-density polyethylene (LDPE). Sorption tests were implemented in batch tests in the laboratory using conventional one-time and multiple spiking methods as well as a cellulose dialysis tubing method. The plastic samples tested here are LDPE pellets with a low amount of additives. For the one-time spiking test, a high concentration of Phen in ethanol was spiked in a 2.5L glass bottle containing MilliQ-water and shaken. The well-mixed solution was placed into several smaller reactors and LDPE was added. For the multiple spiking test, batch reactors containing LDPE and MilliQ-water were prepared. A high concentration of Phen in ethanol was injected repeatedly into each batch reactor until the concentration became stable. For the dialysis tubing test, a closed dialysis tubing containing LDPE and MilliQ-water was placed in each batch reactor filled with MilliQ-water with Phen far above solubility. The water concentration outside of the tubing was expected to stay constant during the entire experiment. The concentration in the water phase for the first two tests as well as in the dialysis tubing for the third test was monitored using high performance liquid chromatography (HPLC). When the adsorption of Phen was completed, Phen on LDPE was to be extracted and quantified. Sorption capacity of Phen was derived from the experiments and methods were compared. PE-water partition coefficient of Phen were derived based on the sorption capacity using adsorption models. TU Darmstadt and CARAT are participants of an EU project „PLASTOX“, a consortium of a JPI Ocean’s Joint Action.

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