| Abstract |
Surface and underground fresh waters are used to supply our need for
drinking water. Chlorine is the most common drinking water disinfectant, among various chemicals, used to eliminate hazardous microorganisms present in fresh waters. The main problem occurring from the use of chemical disinfectants is the
formation of the disinfection by‐products (DBPs) occurring through their reaction with the organic matter content of raw water. Since many DBPS have been classified as probable carcinogens, there is a growing interest to study their occurrence and
formation mechanisms during the disinfection process. The main compound classes studied in this thesis are the organic DBPs produced by the use of chlorine, namely the halogenated organic compounds thrihalomethanes (THMs), haloacetonitriles (HANs), haloacetic acids, and the inorganic DBPs formed by the use of chlorine dioxide and ozone specifically chlorate (ClO3‐) and bromate (BrO3‐) ions respectively.
In the present study, sensitive and selective analytical methods were
developed and/or optimized to determine the above‐mentioned DBPs in drinking water samples. The current methods for the analysis of organic DBPs and especially of the HAAs are not suitable for the determination of these compounds at low concentration levels. In this work, the following analytical methods were developed,
optimized and then applied for the analysis of DBPs in various drinking waters: Gas Chromatography/Electron Capture Detector (GC/ECD) and Gas Chromatography/ Mass Spectrometry (GC/MS) in electron and negative chemical ionization modes (EI and NCI respectively) with on column injection, Ion Chromatography/ Electrospray Ionization Mass Spectrometry (IC/ESI‐MS), and Ion Chromatography/Conductivity Detector (IC/CD). The detection limits for volatile
compounds (THMs, HANs, HKs) analyzed with GC‐ECD method were obtained at ranges from 0.2 up to 0.8 μg/L. The corresponding detection limits for HAAs analyzed with the GC‐NCI‐MS method ranged from 3.0 ng/L up to 1.8 μg/L. These methods allowed a reliable determination of DBPs, even at very low concentration in drinking and swimming pool waters. At the same time, the ionic content and organic carbon levels were also in the studied drinking water and swimming pool water samples.
Dissolved organic carbon concentration levels ranged between 30 μg/L‐4.8 mg/L for drinking waters and 0.2‐33.0 mg/L for swimming pool waters.
The analysis of drinking water from Heraklion (supplied from groundwater),
from Athens and Barcelona (supplied from surface fresh water) revealed important differences in their corresponding DBPs content. DBPs were determined in higher
concentration levels in Barcelona (ΤΤΗΜs: 10.45‐135.44 μg/L, HAAs: δ.α.‐35.86 μg/L) and Athens (ΤΤΗΜs: 18.94‐38.25 μg/L, HAAs: 2.28‐28.17 μg/L) than in Heraklion samples (ΤΤΗΜs: 0.004‐44.28 μg/L, HAAs: δ.α.‐2.83 μg/L). The brominated THMs,
HANs and HAAs dominated the chlorinated analogues in the Heraklion samples, in comparison with the samples from Athens and Barcelona, due to the presence of high concentration of bromide ions in the groundwater.
The high levels of organic matter in indoor and outdoor swimming pools,
originating from swimmers, contributed to their higher DBPs content in the
corresponding water samples. In swimming pools, the formation of chlorinated DBPs was favored in comparison to the brominated ones, which were detected in their
water at higher levels than in the drinking water of the same area. The presence of nitrogen in the human related organic matter contributed to the relatively higher concentration of HANs (0.4‐21.7 μg/L) in swimming pools than in the related drinking
water. The HAAs were also determined in higher abundance (0.2‐709.7 μg/L)
compared to the THMs (8.1‐57.4 μg/L), which was the main category of DBPs in the drinking water supplying the swimming pools. Additionally, inorganic DBPs such as chlorates were detected in swimming pool waters between 6.1 and 327.2 mg/L.
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Μελέτη του σχηματισμού και της παρουσίας συμβατικών και αναδυόμενων αλογονομένων πολικών παραπροϊόντων απολύμανσης σε πόσιμα ύδατα
