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- Perfluorooctane Sulfonate (1) (remove)
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Perfluorooctanoic Acid (PFOA) and Perfluorooctane Sulfonate (PFOS) in an Aquatic Ecosystem - Distribution and Fate
(2009)
- Perfluorooctanoate (PFOA) and perfluorooctane sulfonate (PFOS) belong to the family of perfluorinated surfactants (PFSs). They are widely distributed and persistent in the environment. For over 50 years, they have been used in numerous applications including paper and textile treatment, production of fluoropolymers, cosmetics and insecticides formulations, and fire fighting foams. They can enter the environment via direct and indirect emission sources such as manufacturing processes, use of commercial products containing PFSs, release of waste waters or degradation of precursor substances. Due to their physical-chemical properties, i.e. relatively good solubility, low volatility and stability under environmental conditions, water bodies are important sinks for these chemicals. The aim of this doctoral thesis was to elucidate sources, distribution and fate of PFOA and PFOS in an aquatic ecosystem that is not directly affected by fluorochemical production activity. The presented study was mainly focused on the river Roter Main, Bayreuth, Germany, and gives a good picture of the behaviour of PFOA and PFOS in such an aquatic ecosystem. In order to achieve the main goal, suitable analytical procedures for reliable quantification of trace amounts of the target analytes in different environmental matrices such as water, liquid and solid wastes, sediments, biological tissues, were developed or optimised. Each method included a solid-phase extraction step for analytes’ preconcentration and removal of interfering matrix, followed by quantitative determination via high performance liquid chromatography coupled to electrospray ionisation tandem mass spectrometery (HLPC-ESI-MS). Due to the possibility of ionisation suppression, isotope dilution or standard addition method was applied. Analysis of waste waters collected from four different waste water treatment plants (WWTPs) located in Upper Franconia, Bavaria, Germany, showed that the largest plant (Bayreuth) receiving waste waters of mostly commercial and industrial origin released the highest amount of PFOA and PFOS, whereas the smallest plant (Himmelkron) treating waste waters of only domestic source released the least. The monitoring of waste waters from the WWTP Bayreuth enabled to estimate the typical mass flows of PFOA and PFOS into river waters as about 1 and 5 g/day, respectively, showing that a plant of a medium-size, moderately industrialised city can be a major source of river pollution. Detailed investigation of PFOA and PFOS concentrations in liquid and solid wastes collected at different stages of the treatment process showed additional fluxes of these compounds inside the plant, likely due to the decomposition of their precursors. Analysis of sediments collected from the river receiving treated waste waters showed a significant increase in concentrations of both analytes downstream the outlet of the plant (up to 3- and 4-fold for PFOA and PFOS, respectively). PFOS concentrations were up to 40-fold higher in sediments than in river water, showing its higher adsorption potential in comparison to PFOA (max. sediment/water = 6). Once in the river, PFOS, and to a lower extent PFOA, can bioaccumulate in aquatic organisms. Although partially removed from water, they are still bioavailable for benthic organisms inhabiting the river thus entering the food chain. This was reflected in higher levels found in river goby - in comparison to chub - feeding on invertebrates living in the sediment. At the starting point of this doctoral thesis little information was available about environmental contamination with PFOA and PFOS in Germany, and it is the first study performed in Bavaria giving such a detailed picture of sources and fate of PFSs in a river ecosystem
