| Abstract |
Phthalate esters (PEs) are used as additives in polymers in order to improve their plasticity. This process is required for materials such as PET and PVC. The products that PEs are added to, range from electrical cables, adhesives and floor coverings to water and food packaging, cosmetics, medical devices and medicines. Because PEs are not chemically bound to the plastics they are added, they are continuously released into the air, food and liquids. Humans are exposed through ingestion of food and water contaminated with plasticizers, inhalation and dermal exposure during their whole lifetime. PEs possess endocrine disrupting properties. They are among the chemicals of concern called emerging pollutants. The aim of this thesis was to investigate the occurrence of PEs in potable waters from Crete. The experimental procedure was based upon the protocol of US Environmental Protection Agency (US–EPA). Liquid–liquid extraction with dichloromethane was employed for the isolation of the target analytes. The analysis was performed using a gas chromatograph coupled with a quadrupole mass spectrometer (GC/MS). Nevertheless, the US–EPA method was modified to become faster and to consume less amounts of solvents. Thus, the bank problems were minimized and the method detection limits (MDL) were lowered up to 3.6–53.7 ng/L for DMP and DEHP respectively. Linearity with R2
values ≥0.9990 was observed for all PEs. The observed repeatability for all PEs was very satisfactory (RSD: 0.23%-3.44%). Municipal drinking water, in the major cities of Crete, circulating through plastic pipes and stored in plastic storage tanks. The contact of the water with the plastic might cause its contamination with PEs. We collected samples from the drinking water supply network of Heraklion, Rethymno and Chania, which were analyzed for PEs. In addition, drinking water in PET bottles was also analyzed for the same purpose. DEP, DiBP, DBP and DEHP were detected in some water samples. The maximum concentration of DEHP in tap water was 2.04 μg/L. This value is below the maximum admissible concentration value of 6.0 μg/L DEHP in drinking water established by the US–EPA. The concentration, of the examined compounds in tap water, was affected by the seasonal ambient temperature fluctuations and the water temperature (r=0.994, p-value=0.0001). Boiling of tap water resulted in decreased concentrations of PEs. The obtained results of the tap water analysis were compared with those from laboratory experiments of plastic pipes leaching with water.
The calculated daily intake of PEs via tap water drinking was 3.35 μg/kg for adults and 11.7 μg/kg for children. Ingestion of water is the main route of exposure to PEs and accounts for the 88.2% of the total intake. The rest of it refers to exposure through inhalation and dermal adsorption during bathing and showering. The concentration of PEs measured in bottled water was by far lower than those found in tap water. The daily intake via bottled water drinking is almost insignificant.
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Προσδιορισμός φθαλικών εστέρων σε πόσιμα ύδατα στην Κρήτη
