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(16-13) Removal efficiency of two polycyclic musks in sewage treatment plants: Free vs. total concentration. Artola-Garicano, Elsa*,1, Borkent, Iris1, Vaes, Wouter2, Hermens, Joop1, 1 Institute for Risk Assessment Sciences (IRAS), Utrecht, The Netherlands2 TNO Food and Nutrition Research, Zeist, The Netherlands ABSTRACT- The main purpose of sewage treatment plants (STPs) is to decrease the concentration of chemicals in the plant through degradation or sorption to levels that are not harmful to the environment. Usually, the removal efficiency is evaluated based on "total concentration" data. However, information about free concentrations is more relevant since only the freely dissolved concentration of a chemical is available for (environmental) partition and degradation processes, e.g. uptake into organisms, biodegradation, evaporation etc. This means that the free concentration is a more relevant entity and that therefore, its profile along the STPs should also be considered. The objectives of the current work were (i) to study the removal efficiency of AHTN and HHCB based on free concentration using negligible depletion solid-phase microextraction (nd-SPME) and (ii) to compare the results with the classical way of determining the removal efficiency (total concentration). Results show that the free concentration remain constant along the STPs, while the removal of the total concentration depends of the organic carbon content present in each compartment. This study shows that the efficiency of the STP in reducing the free concentration and the removal of these compounds, is very low. Key words: Sewage treatment plant, polycyclic musks, free concentration, nd-SPME |
