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An investigation into the occurrence of priority substances regulated by 2000/60/EC Water Framework Directive and 2008/105/EC Directive was conducted for a period of one year in the surface water sources supplying the water treatment plants (WTPs) of Athens and in the raw water of WTPs. Samples from four reservoirs and four water treatment plants of Athens were taken seasonally. The substances are divided into seven specific groups, including eight volatile organic compounds (VOCs), diethylhexylphthalate, four organochlorine pesticides (OCPs), three organophosphorus/organonitrogen pesticides (OPPs/ONPs), four triazines and phenylurea herbicides, pentachlorophenol, and four metals. The aforementioned substances belong to different chemical categories, and different analytical methods were performed for their determination. The results showed that the surface waters that feed the WTPs of Athens are not burdened with significant levels of toxic substances identified as European Union (EU) priority substances. Atrazine, hexachlorocyclohexane, endosulfan, trifluralin, anthracene and 4-nonylphenol were occasionally observed at very low concentrations. Their presence in a limited number of cases could be attributed to waste disposal, agricultural activities, and to a limited industrial activity in the area nearby the water bodies.

This study aimed to optimize two oxidation processes for wastewater reuse of an urban wastewater treatment plant (UWWTP) effluent intended for human consumption. Ozonation and TiO2 photocatalytic oxidation (PCO) processes were compared for their effectiveness in terms of organic matter degradation (measured as UV absorbance at 254 nm, UV254), disinfection by products formation (measured as trihalomethanes formation potential, THMFP), and ecotoxicity (evaluated by Daphnia magna and Lepidium sativum), on secondary treated wastewater collected from a UWWTP in the province of Salerno (southern Italy). Accordingly, ozonation experiments using 28 mg/L ozone dose and PCO experiments using 250 W lamp (emission range: 315–400 nm; emission peak: 14.7 μW/cm2 at 340 nm) and varying TiO2 dose from 1 to 3 g/L were carried out. Ozonation (t1/2 = 71.6 min) was not found as effective as PCO for organic matter degradation at all TiO2 doses, and 3 g/L of TiO2 was found to be the most effective photocatalyst loading ...

In this work, ozone oxidation combined with ferric chloride and aluminum sulfate (Alum) coagulations was employed to investigate the optimum conditions for the control of the toxicity to Daphnia magna and Pseudokirchneriella subcapitata and disinfection by-products (DBPs) formation potential of Buyukcekmece (BC) lake water in Istanbul, Turkey. The effi ciency of the treatment was determined by means of UV absorption at 254 nm (UV254) and dissolved organic carbon (DOC) parameters. Four species of trihalomethanes (THMs) and eight species of haloacetic acids (HAAs) were identified and quantifi ed for the evaluation of treatment methods on the formation of DBPs. It was observed that pre-ozonation enhanced DOC removal efficiency of alum and ferric chloride coagulations. 40 mg/l optimal alum and ferric chloride doses respectively exhibited 51% and 56% DOC reduction after 5 min pre-ozonation. As a result, THMs formation potential (THMFP) decreased approximately 43% after ozone enhanced alum and ferric chloride c...

The occurrence of polycyclic aromatic hydrocarbons (PAHs) in the marine environment has attracted the attention of the scientific community, as these compounds are frequently detected in seawater and sediments at increasing levels and can have adverse health effects on marine organisms and humans. Several PAHs are potential human carcinogens and are included in the priority list of the European Union’s Water Framework Directive (2000/60/EC). Research regarding their environmental levels requires their determination by gas-chromatography and liquid-chromatography techniques, which have been developed and optimized, especially for marine-sediment samples. Results of sample analyses reveal the increasing occurrence of many species of PAHs worldwide, especially in marine sediments, where they finally accumulate, mostly in areas near intense industrial activities. In parallel, research on the toxicity of PAHs and their mixtures is continuing and is aiming to provide more insight into the health risks associated with the levels of PAHs in the environment.

The occurrence of pharmaceuticals in the aquatic environment is of increasing research interest, as modern sensitive techniques are used worldwide for their determination. Pharmaceuticals and their metabolites are among the most important classes of chemicals currently being investigated in environmental matrices at trace levels with techniques such as gas chromatography-mass spectrometry (GC-MS) and liquid chromatography-mass spectrometry (LC-MS). We discuss analytical developments in the past 10 years, with particular emphasis on sample-preparation procedures and related analytical problems and needs.

The aim of this paper is to elaborate strategies, methodologies and techniques for integrated water resource management within the philosophy of the EC Water Framework Directive (2000/60/EC) for the trans-boundary river basin of Evros which is shared by two EU (Greece, Bulgaria) and an EU-candidate country (Turkey). With the recent comer EU Member States the number of trans-boundary rivers has increased, therefore, management scheme development for trans-boundary rivers gained more importance to implement WFD 2000/60/EC. Development of a sustainable integrated water management (IRWM) scheme is needed by utilizing the multidisciplinary information resulting from the research activities in the similar EU river basins (e.g. the Ebro, Spain), development of a sustainable integrated water management (IRWM) scheme is needed. The IRWM should incorporate quantity and quality aspects, river modelling by taking into account natural disasters of floods and droughts, monitoring of physico-chemical and biological parameters as well as priority substances recently regulated by environmental quality standards regarding WFD 2000/60/EC.

The presence of organic compounds in bottled waters available in the Greek market and their fate when the representative samples exposed at different conditions were the main purposes of this study. The determination of the organic compounds was performed by gas chromatography–mass spectrometry techniques. Disinfection by-products compounds, such as trihalomethanes (THMs) and haloacetic acids (HAAs), were detected at low concentrations in bottled waters. As far as it concerns other organic substances, Greek bottled drinking waters did not contain volatile organic compounds (VOCs), and carbonyl compounds as well as other carcinogen and hormone disrupter phthalates were not identified, except for the plasticiser phthalate, diethylhexyl phthalate (DEHP). Moreover, samples contained other organic chemicals, whose identity has not yet been confirmed. The behavior of organic compounds was influenced by parameters such as conditions of storage, type of water. Finally, a comparison has been performed between the analysis of bottled and local tap waters.

AWSC (Athens Water Supply and Sewerage Company) uses chlorine as an acceptable disinfectant. An unwanted side effect of chlorination is the formation of by-products. One of the most significant groups of disinfection by-products is the trihalomethanes. Water companies have to keep their concentration levels lower than the limits that the E.U. Directive has set. In search of a relationship between raw water organic carbon, residual chlorine, TTHMs formation and detention time in a water company distribution system, kinetics studies were performed in the laboratory. Chlorine was added to Mornos river raw water and the concentrations of the parameters mentioned above (TTHMs) were determined at regular time intervals by the use of a gas chromatography-electron capture detector (GC-ECD) method. Instead of DOC, absorption in 254 nm wavelength was measured. Two different temperatures were studied. The differences between lab conditions and the real system (AWSC waterworks as well as distribution system) are discussed.

The objective of this pilot study was to evaluate the performance of a GAC postfilter-adsorber for the removal from the drinking water of Athens, Greece, of the two main groups of chlorination by-products, trihalomethanes (THMs) and haloacetic acids (HAAs), as well as of dissolved organic carbon (DOC). The analyses performed during the whole operation period (638 days) showed that the GAC breakthrough capacity for DOC was much higher than the capacity for total HAAs, which was higher than that for total THMs. The removal of THMs and the most part of the removal of HAAs and DOC should be attributed to adsorption by GAC, while that of a smaller part of HAAs and DOC may be attributed to biodegradation in the adsorber bed, where dechlorination, caused catalytically by the carbon surface, favoured microbial growth. Additionally, the GAC postfilter-adsorber showed a much higher adsorption efficiency than a GAC filter-adsorber, due to the smaller size of the carbon and the lower hydraulic loading rate. Also, observed desorption incidents of THMs (mainly) and HAAs, especially during the postfilteradsorber operation, were favoured by the same factors. Formation of THMs within the GAC bed was also indicated by the mass balance of total THMs during the whole cycle.

Polycyclic aromatic hydrocarbons (PAHs) as well as nonylphenol (NP) and octylphenol (OP) are substances of major environmental concern because of their adverse health effects on organisms, including endocrine disrupting activity. Seven PAHs, NP and OP have been included in the priority list of substances regulated by 2000/60/EC Water Framework Directive. The present work concerns the investigation of the occurrence of the seven priority PAHs, NP and OP in surface and coastal waters in Central Greece and the Island of Lesvos. Samples were collected and analyzed seasonally for one year from the four reservoirs that supply water to Athens: Mornos, Marathonas, Yliki and Evinos. Samples were also collected from inland waters of the Lesvos Island (the rivers Mylopotamos and Evergetoulas), and from coastal waters (five sampling points) of the Mytilene area, which is the capital city of the Island of Lesvos. The results have shown that in most cases the water samples that were analyzed are free from PAHs, possibly because of lack of PAHs release sources nearby the particular areas, or due to the adsorption of PAHs on sediments. NP occurred at low levels in several cases, while OP was detected only in one sample.

Organotin compounds belong to the priority list of substances regulated by 76/464/EEC Directive, as well as by 2000/60/EC Water Framework Directive, because they pose considerable risks to the environment and human health. They are the most commonly used organometallic compounds with estimated global amount produced 50,000 tons per year. Therefore, they have been detected worldwide in surface waters, drinking water, sediments and biota. The objective of the present investigation was the determination of these compounds in the water sources supplying the drinking water treatment plants of Athens, Greece, in particular at the reservoirs Mornos, Marathonas, Yliki and Evinos. The quality of water of those reservoirs could be affected from human activities, such as industry and agriculture, as well as from settlements in the area nearby. The surface water sampling campaigns executed were seasonal, during the period March 2004–May 2005, while finished drinking water samples from the distribution network of Athens were also analyzed. Six organotin species (monobutyltin, dibutyltin, tributyltin, monophenyltin, diphenyltin and triphenyltin) were determined by a gas chromatography — flame photometric detector (GC-FPD) method, after sample pretreatment with simultaneous liquid–liquid extraction with hexane and derivatization with tetraethyl borate. The results showed that the waters studied are free from organotin compounds, except for a limited number of samples, where the occurrence of some organotin species at low concentrations was observed.

The aim of this work was to compare the behaviour of Fenton and photo-Fenton (UV-A, UV-C) processes to treat synthetic tannin (syntan) used in leather tannery which is one of the most polluting industries, releasing many xenobiotics. Both oxidation processes were performed at pH 3.0 and temperature 40–45 °C, which is the original temperature of the re-tanning process, in synthetic solutions containing 100 and 300 mg/L of COD equivalent of syntan. The efficiency of the applied oxidation processes was monitored by chemical oxygen demand (COD), oxidation redox potential (ORP) and aromaticity (UV280) and double bond (UV254) absorbance measurements. Acute toxicity test on Daphnia magna was performed to monitor toxicity in untreated and treated syntan solution. Gas chromatography–mass spectrometry (GC-MS) was applied to identify by-products of partial oxidation occurring in treated samples. The effective ratio of H2O2/FeSO4 for photo-Fenton processes was found to be feasible in terms of reagents used in the process.

Two gas chromatography methods were developed for the determination of the acaricide bromopropylate in grapes. The first included chromatographic separation with a DB-1 column and electron capture detection (GC-ECD), while the second utilized chromatographic separation with a DB-5MS column and mass spectrometry detection (GC-MSD). Sample preparation was the same for both methods and included liquid–liquid extraction with dichloromethane and diethylether, centrifugation, and evaporation. The sample preparation and analysis steps were optimized. The evaluation of the methods by analysis of standard solutions of bromopropylate in hexane gave satisfactory results. The detection limits were 0.02 mg kg−1 for the GC-ECD method and 0.03 mg kg−1 for the CG-MS method, and the corresponding quantification limits were 0.04, and 0.06 mg kg−1, respectively. However, the analysis of spiked grape samples showed that the GC-ECD method could be problematic for the particular substrate. In the cases of very low concentratio...

An investigation into the occurrence of disinfection by-products (DBPs) was conducted for a period of two years (2001–2002) on the drinking water of Athens, Greece. Samples from four water treatment plants (WTPs) and from the distribution system of Athens were collected monthly and analyzed for DBPs. The concentrations of DBPs were determined by the gas chromatography-mass spectrometry (GC-MS) method, which included sample preparation with liquid-liquid extraction (LLE) for volatile DBPs and an acidic method of esterification for haloacetic acids (HAAs). The DBPs studied included trihalomethanes (THMs), haloacetonitriles (HANs), haloketones (HAKs), chloral hydrate (CH), chloropicrin (CP) and nine HAAs. The results of the analyses show the presence of DBPs in all water samples collected after prechlorination. The most commonly encountered DBPs were chloroform (CM), trichloroacetic acid (TCAA), dichloroacetic acid (DCAA) and monochloroacetic acid (MCAA), while other volatile DBPs were detected at low concentrations. The annual mean concentrations of CM in four WTPs ranged from 8.0 to 42.5 μg/l, while the annual mean concentrations of TCA, DCA and, MCA varied from 3.5 to 18.1 μg/l, from 2.3 to 24.5 μg/l, and from 1.1 to 61.8 μg/l, respectively. Higher concentrations of THMs and HAAs were measured in the summer and fall compared to winter. In all cases the concentrations of TTHMs were lower than the maximum level set by the European Community.

The formation of chlorination by-products (CBPs) was investigated through bench-scale chlorination experiments with river water. The compounds selected for analysis belonged to the groups of trihalomethanes, haloacetic acids, haloketones and haloacetonitriles. Trihalomethanes and haloacetic acids were the major species formed during chlorination, while haloketones and haloacetonitriles occurred at lower levels. The factors affecting the formation of these compounds were examined by two sets of experiments; the first with varying pH and reaction time, and the second with varying chlorine dose and temperature. Different effects of these factors were observed for different categories of CBPs, and in many cases, these effects were compound-specific, as confirmed by statistical analysis. Optimization of chlorination conditions in water treatment plants is a critical issue that should take into account the influence of chlorination parameters on the formation of individual CBPs.

The presence of organic chlorination by-products (CBPs) in drinking waters has caused great public health concerns. One of the most important factors affecting their formation during the disinfection procedure is reaction time. The kinetics of the formation of CBPs can be different for the different categories or species of compounds, depending also on the chlorine dose, organic matter content and the presence of bromide ion. Decomposition of some CBPs also occurs due to hydrolysis or reactions with residual chlorine. Therefore, the final concentrations of individual species of CBPs reaching the consumers’ tap may deviate from the predictions. The aim of the present investigation was the determination of formation or decomposition kinetics of CBPs during chlorination of natural waters. 24 CBPs were studied in chlorinated water from three different sources. Different speciation of CBPs and different formation rates were observed for different water quality regarding bromide ion presence and organic matter content. Decomposition of some CBPs occurred, specifically haloketones, BCA and DBA, after an initial formation step. The percentages of incorporation of chlorine and organic matter into CBPs indicated that other halogenated compounds not identified during the present study have also been formed during chlorination. The importance of chlorine dose for the formation of CBPs and for the incorporation of organic matter was highlighted. Moreover, linear correlations were observed between the concentrations of chloroform-MCA, chloroform-DCA and chloroform-TCA as well as between total THMs and total HAAs, in all waters studied.

An investigation of the behavior of different categories of disinfection byproducts (DBPs) in ultrapure water and in spiked drinking water samples was performed. The influence of sunlight, pH, and time was examined. Several of the compounds were subject to degradation with time, while others showed increasing trends, possibly due to natural production by bacteria. Chloroform, monochloroacetonitrile, and monochloroacetic acid slightly increased in the presence of sunlight, while d ichloroacetonitrile, dibromoacetic acid, tribromoacetic acid, and mixed bromo-chloro acetic acids were subject to decomposition, especially under sunlight. However, sunlight was found to decelerate decomposition of trichloropropanone and to prevent decomposition of bromochloro-acetonitrile and chloral hydrate. Trichloropropanone decomposed to chloroform, while mixed haloacetic acids decomposed to the corresponding trihalomethanes. Multiple regression equations were obtained for the concentrations of i ndividual DBPs in drinking w...

The formation of disinfection by-products (DBPs) during chlorination of drinking water is an issue which has drawn significant scientific attention over the last few years, due to the adverse effects of these compounds on human health. The complicated mechanisms of the formation of DBPs are still under investigation, and modelling attempts are being made. One of the major factors affecting the yields of DBPs is the concentration of bromide ion. In bromide-rich waters, the brominated species—bromoform, dibromoacetic acid—which are considered more toxic than their chlorinated analogues, may be the major species formed and therefore the consumption of these waters may be more harmful to human health than the consumption of water containing chlorinated species (chloroform, dichloroacetic acid). During this study, the effect of bromide ion on DBP formation was investigated by bench-scale chlorination experiments and statistically evaluated for individual species of DBPs. The importance of interactions between pairs of chlorination factors, pH, bromide concentration, chlorine dose and time for DBP formation was highlighted by statistical analysis results. Moreover, multiple regression models were developed for the concentrations of total trihalomethanes and total haloacetic acids, the two major DBP groups formed. The models developed provide satisfactory estimations of, but also indicate different formation mechanisms for, these two groups of DBPs.

Chlorination is the most widely used technique for disinfection of drinking water. A consequence of chlorination is the formation of Disinfection By-Products (DBPs). The formation of DBPs in drinking water results from the reaction of chlorine with naturally occurring organic materials, principally humic and fulvic acids. This paper focuses on the effect of humic substances on the formation of twenty-four compounds belonging to different categories of DBPs. This investigation was conducted in two water treatment plants in Greece, Menidi and Galatsi, from July 1999 to April 2000. Humic substances were determined by the diethylaminoethyl (DEAE) method with subsequent UV measurement. The techniques used for the determination of DBPs were liquid-liquid extraction, gas chromatography and mass spectrometry. The concentrations of DBPs were generally low. Total trihalomethanes (TTHMs) ranged from 5.1 to 24.6 microg L(-1), and total haloacetic acids (HAAs) concentration ranged from 8.6 to 28.4 microg L(-1), while haloaketones (HKs) and chloral hydrate (CH) occurred below 1 microg L(-1). The content of humic substances was found to influence the formation of DBPs and especially TTHMs, trichloroacetic acid (TCA), dibromoacetic acid (DBA), CH, 1,1-dichloropropanone (1.1-DCP) and 1,1,1-trichloropropanone (1,1,1-TCP). Seasonal variation of TTHMs and HAAs generally followed that of humic substances content with peaks occurring in autumn and spring. The trends of 1,1-DCP, 1,1,1-TCP and CH formation seemed to be in contrast to TTHMs and HAAs. Trends of formation of individual compounds varied in some cases, probably due to influence of parameters other than humic substances content. Statistical analysis of the results showed that the concentrations of TTHMs, CH, 1,1-DCP, 1,1,1-TCP, TCA and DBA are strongly affected from humic substances content (at 0.01 confidence level). The opposite is true for dichloroacetic acid (DCA) concentration. Humic substances also vary to a statistically significant degree during different months, as well as the concentrations of TTHMs, CH, 1,1-DCP, 1,1,1-TCP, TCA and DCA. The variance of DBA was not statistically significant. Regarding the effect of sampling station, humic substances content showed no statistically significant difference between the two raw water sources studied.

Bench-scale chlorination experiments with river water rich in bromide and organic matter content were performed in order to investigate the behavior and speciation of the chlorination by-products, especially the brominated ones, which are considered more harmful to human health than their chlorinated analogues. The analysis of the compounds was performed by means of gas chromatography. Statistical treatment of the results with Multifactor Analysis of Variance technique revealed the trends of each compound as function of pH, chlorine dose, reaction time and temperature. Brominated species of chlorination by-products predominated, due to the presence of bromide in the river water leading to preferable bromination than chlorination of the organic matter. Bromide incorporation factors were calculated for trihalomethanes and haloacetic acids, the major categories of compounds formed. While bromide incorporation factors decreased with increasing chlorine dose, the opposite was true for low range of chl...

Application of chlorination for the disinfection of drinking water results in the formation of a wide range of organic compounds, called disinfection by-products (DBPs), which occur due to the reaction of chlorine with natural organic materials. The occurrence of DBPs was studied in samples from four drinking-water treatment plants (WTPs) and from the distribution network of Athens, Greece. Twenty-four compounds, which belong to different categories of DBPs, were monitored, including trihalomethanes (THMs), haloacetic acids (HAAs), haloacetonitriles (HANs), haloketones (HAKs), chloral hydrate (CH) and chloropicrin (CP). Sampling was performed monthly for a period of two years, from three different points at each WTP and from eight points atthe distribution network. Samples were analyzed by GC-ECD methods, which included pretreatment with liquid-liquid extraction for volatile DBPs and acidic methanol esterification for HAAs. The results of the analyses have shown the presence of disinfection by-products belonging to all categories studied in all water samples collected after prechlorination. The major categories of DBPs detected were THMs and HAAs, while the other volatile DBPs occurred at lower concentrations. The concentrations of DBPs did not in any case exceed the maximum contaminant levels (MCL) set by USEPA and WHO. However, monitoring these compounds needs to be continued, because their levels could increase due to changes in the quality of water entering the water treatment plants. Reduction of the concentrations of DBPs could be achieved by optimization of the chlorination conditions, taking into account the effect of time. Moreover, research on alternative disinfection methods (e.g. ozone, chlorine dioxide, chloramines) and their by-products should be conducted to evaluate their applicability in the case of the drinking water of Greece.

Natural water from six sources in Mytilene, Greece, was chlorinated in order to identify and quantify some of the organic by-products formed. The compounds examined were trihalomethanes, haloacetic acids, haloacetonitriles, haloketones, chloral hydrate and chloropicrin. The factors tested were time and chlorine dose. The presence of bromide ion in some of the waters studied resulted in significant changes in the by-product speciation, with enhanced brominated species formation. In addition, UV absorbance, measured at three wavelengths, led to correlation of organic matter content with the concentrations of by-products produced. The species formed, varying among different water sources, increased with increasing chlorine dose. Most of the species also increased with increasing contact time, although there were some exceptions due to hydrolysis reactions.

The role of natural organic matter (NOM) in chlorination by-product formation in drinking water is complex, since characteristics of NOM and its behavior during water treatment have not yet been clearly identified. Different approaches have been applied to characterize NOM, with the objective to investigate the mechanisms of its reactions with chlorine. In this way, formation of by-products, which may have adverse health effects on humans, could be minimized. These approaches are summarized in the present review. Efforts to correlate NOM properties with formation of chlorination by-products and conclusions resulting from chlorination of humic and fulvic acid as well as raw water are also discussed.

The behaviour of the haloketones (HKs) 1,1-Dichloropropanone (1,1-DCP), 1,1,1-Trichloropropanone (1,1,1-TCP) and 1,3-Dichloropropanone (1,3-DCP) in ultrapure water solutions and in fortified drinking water samples was investigated. Their concentrations were determined at regular time intervals by the use of a gas chromatography-electron capture detector (GC-ECD) method. Two different temperatures were studied. The results have shown that HKs decompose both in ultrapure water solutions and in drinking water samples. The decomposition rates are higher in the drinking water samples, especially at higher temperature. 1,1,1-TCP is the compound which decomposes fastest followed by 1,3-DCP and 1,1-DCP. Chloroform was formed both in the ultrapure water solutions and in the drinking water samples, probably due to the decomposition of 1,1,1-TCP. In the drinking water samples, formation of chloral hydrate was also observed.

On a monthly basis, on a one year period, disinfection by-products (DBPs) and volatile organic compounds (VOCs) were measured in raw water and in treated water of four water treatment plants (WTP) as well as from eight representative points of the distribution network of Athens. Liquid-liquid extraction (LLE) method followed by gas chromatography (GC) with electron capture detection (ECD) and mass spectrometry (MS) was used for the determination of the DBPs, while the purge-and-trap (PAT) technique followed by GC-MS was used for the determination of the VOCs. The DBPs that have been studied included trihalomethanes (THMs), haloacetonitriles (HANs), haloketones (HKs), chlorate hydrate (CH) and chloropicrin (CP), while forty-one VOCs were also studied including THMs. Chloroform (CM), dichlorobromomethane (DCBM), chlorodibromomethane (CDBM) were the major organic compounds found in all treated water samples. HANs, HKs, CH and CP were detected in treated samples but at lower concentrations.

An investigation of the decomposition of dihaloacetonitriles (DHANs) in water solutions and fortified drinking water samples was conducted. The concentrations of dichloroacetonitrile (CHCl2CN, DCAN), bromochloroacetonitrile (CHBrClCN, BCAN) and dibromoacetonitrile (CHBr2CN, DBAN) were determined by a gas chromatography mass spectrometry (GC-MS) method at regular time intervals and different temperatures. The effect of sodium thiosulfate (Na2S2O3), which is used as a preservative in water samples, was also examined. The rates of decomposition were determined for each compound. The results show that the reactions are faster in fortified drinking water samples than in ultrapure water solutions. They are also favored at higher temperature, especially when sodium thiosulfate is present. The highest decomposition rate is shown by DCAN, followed by BCAN and DBAN, while at the presence of sodium thiosulfate the decomposition of DBAN is the fastest.

Environmental research nowadays is focusing more and more on different categories of emerging contaminants, because of their increasing release into the environment, the lack of information regarding the occurrence and health effects of the parent compounds, and, even more, of their transformation products, and the need for the development and optimisation of analytical methods for their determination in environmental samples. Emerging contaminants and transformation products are detected by advanced analytical methods such as liquid chromatography (LC) or gas chromatography (GC) combined with tandem mass spectrometric (MS/MS) detection. The rapid development and improvement of these methods during the last few years provides the opportunity not only to determine trace levels of emerging pollutants in environmental samples, but also to identify and detect their transformation products. This is a particularly important step towards safeguarding environmental quality and human health.

For much of the past 30 years, research on the effects of chemical pollution on the environment has focused almost exclusively on ‘conventional’ priority pollutants. However, during the past several years, there has been a growing level of concern related to the hypothesis that various chemicals may exhibit endocrine-disrupting effects. The presence, for example, of steroid hormones and pharmaceuticals in wastewater treatment plant effluents, receiving waters, drinking and groundwater has become an emerging issue of great interest, although it is probable that these compounds have been entering surface- and groundwater systems for as long as people have been using them. The emerging interest is due to increased incidences of endocrine-related diseases in humans, including declining male fertility, and more significantly, to adverse physiological effects observed in wildlife, where cause and effect relationships are more evident. Pharmaceutical-residue analysis is a clear example of improvement in analytical techniques in recent years. In this respect, following appropriate sample preparation, scientists can at present detect nanogram per liter of such active compounds in waters. Pharmaceuticals considered as pseudopersistent pollutants enter the environment at very low concentrations but on a continuous basis. Therefore, the recent advances in their analysis and quantification down to the nanolevels are quite important for the protection of the environment. These techniques include solid phase extraction (SPE), solid phase microextraction (SPME), gas chromatography (GC) tandem mass spectrometry (MS), liquid chromatography (LC) tandem MS, ultraperformance liquid chromatography (UPLC), and quadrupole ion trap-time-of-flight (Q-TOF).

The present chapter focuses on the identification of sources and fluxes of xenobiotic compounds in marine sediments to set strategies for minimizing impacts on the human life and environment. It is generally accepted that sediments constitute a sink for the more hydrophobic compounds, posing an unacceptable risk to aquatic biota, in which these compounds can bioaccumulate, and to human health through the ingestion of contaminated fish and shellfish.

Water samples of different origins (Buyukcekmece and Omerli, Istanbul, Turkey, and Alento, Salerno, Italy) were treated by coagulation, ozonation, and coagulation followed by ozonation and photocatalysis. Disinfection by-products (DBPs) formation potential of raw and treated water samples was compared in relation to removal efficiencies by the respective treatment methods. The major DBPs, namely trihalomethanes (THMs) and haloacetic acids (HAAs), and other DBPs were identified and quantified. Besides major THMs and HAAs, the presence of bromoform in high amounts was also detected due to the high levels of bromide ions in raw Buyukcekmece and Omerli water samples. Depending on the natural organic matter (NOM) removal efficiencies of each treatment process, the distribution of individual THMs and HAAs was found to be NOM-site specific. Other DBPs were also detected and chloral hydrate (C2H3Cl3O2) was found in significant amounts. The responsible precursor sites could only be reduced by photocatalytic treatment of NOM. © 2005 Elsevier B.V. All rights reserved.

The occurrence of disinfection by-products (DBPs) in drinking water has been an issue of major concern during the last years due to their adverse health effects. The development and optimization of analytical methods for the determination of DBPs in water are key points in order to estimate human exposure to DBPs after water treatment. During this study, analytical methods for the determination of major categories of DBPs, trihalomethanes (THMs), haloacetic acids (HAAs), haloacetonitriles, haloketones, chloral hydrate and chloropicrin were optimized and evaluated in order to be applicable for the routine analysis of these compounds in drinking water. The advantages of the optimized methods are the lower amounts of reagents used and the shorter sample analysis time. Recovery tests were conducted for method evaluation, and control charts were created after analyses of standard solutions of DBPs for 1 year. Application of the methods to water samples from Greece and from Italy was performed in order to determine the formation potential of the DBPs studied during chlorination. The similar quality of the two water resources in Greece and Italy resulted in a comparable total concentration of DBPs; but different concentrations of some species of DBPs occurred, possibly due to differences in organic precursors of the waters. The formation potential of HAAs was higher than that of THMs in both cases, which is important for the evaluation of water treatment techniques, especially in Europe, where currently only THMs are regulated.

The biodegradation behavior of four organotin (OT) compounds, namely tributyltin (TBT), dibutyltin (DBT), monobutyltin (MBT) and triphenyltin (TPhT), was studied in lab-scale activated sludge batch reactors. The activated sludge was spiked with the OT compounds at a level of 100 microg l(-1) as Sn. Determination of the OT compounds by GC-FPD after ethylation in the dissolved and particulate phase revealed that 24 h after the start of the experiments, almost the total of OT compounds has been removed from the dissolved phase and is associated with the suspended solids. Calculation of mass balance in batch reactors showed that OT compounds biodegradation was performed via a sequential dealkylation process. Removals due to biodegradation were differentiated according to the parent compound. In experiments with non-acclimatized biomass, a percentage of 27.1, 8.3, 73.8 and 51.3 was still present as TBT, DBT, MBT and TPhT, respectively, at the end of the experiment (18th day). Half-lives (t1/2) of 10.2 and 5.1 days were calculated for TBT and DBT, respectively, whereas apparent t1/2 values could not be determined for MBT and TPhT (t1/2>18 days). The capacity of activated sludge to biodegrade OT compounds in the absence of supplemental substrate indicated that these compounds can be metabolized as single sources of carbon and energy in activated sludge systems. Excluding TBT, the presence of low concentrations of supplemental substrate did not affect the biodegradation potential of activated sludge. The acclimatization of biomass on OT compounds enhanced significantly biodegradation, resulting in significant decreases of half-lives of OT compounds. As a result in the presence of acclimatized biomass, half-lives of 1.4, 3.6, 9.8 and 5.0 days were calculated for TBT, DBT, MBT and TPhT, respectively.

The pollution of the surface waters of Greece from the priority compounds of 76/464/EEC Directive was evaluated. The occurrence of 92 toxic compounds, 64 of which belong to priority compounds of List II, candidates for List I, of 76/464/EEC Directive, was studied in surface waters and wastewater through the developed network of 62 sampling stations, which covers the whole Greek territory. The analytical determination was performed by Purge and Trap-Gas chromatography-Mass spectrometry for volatile and semivolatile organic compounds (VOCs), Gas Chromatography-Electron Capture Detection for organochlorine insecticides, Gas Chromatography-Nitrogen Phosphorous Detection for organophosphorous insecticides, High Performance Liquid Chromatography-Photodiode Array Detection for herbicides, and Electrothermal Atomic Absorption Spectrophotometry and Inductively Coupled Plasma-Atomic Emission Spectrometry (ICP-AES) for metals and the toluene extractable organotin compounds. The concentrations of VOCs and insecticides detected in the surface waters of Greece were very low, whereas the concentrations of herbicides and metals ranged generally at moderate levels. VOCs were detected almost exclusively in the rivers and very rarely in the lakes, while the frequency of occurrence of insecticides, herbicides and metals was similar for rivers and lakes. Water quality objectives (WQO) and emission limit values (ELV) have been laid down in national legal framework for a number of compounds detected in the samples, in order to safeguard the quality of surface waters from any future deterioration. Keywords: Pollution, Surface waters, Greece

Water chlorination results in formation of a variety of organic compounds, known as chlorination by-products (CBPs), mainly trihalomethanes (THMs) and haloacetic acids (HAAs). Factors affecting their concentrations have been found to be organic matter content of water, pH, temperature, chlorine dose, contact time and bromide concentration, but the mechanisms of their formation are still under investigation. Within this scope, chlorination experiments have been conducted with river waters from Lesvos island, Greece, with different water quality regarding bromide concentration and organic matter content. The factors studied were pH, time and chlorine dose. The determination of CBPs was carried out by gas chromatography techniques. Statistical analysis of the results was focused on the development of multiple regression models for predicting the concentrations of total trihalomethanes and total HAAs based on the use of pH, reaction time and chlorine dose. The developed models, although providing satisfactory estimations of the concentrations of the CBPs, showed lower correlation coefficients than the multiple regression models developed for THMs only during previous study. It seems that the different water quality characteristics of the two river waters in the present study is responsible for this phenomenon. The results indicate that under these conditions the formation of THMs and HAAs in water has a more stochastic character, which is difficult to be described by the conventional regression techniques.

A survey undertaken in Northern Greece has shown that organochlorine pesticides are present in the surface waters. Surface water samples have been collected seasonally from four rivers and five lakes for a period of two years. Solid-phase extraction followed by gas chromatographic techniques with electron capture detection was used for the determination of the compounds. The most commonly encountered organochlorine pesticides in surface waters were the isomers of hexachlorocyclohexane, aldrin, dieldrin and endosulfan sulfate. In some cases the concentrations detected were higher than the qualitative target levels set by the European Union, especially for hexachlorocyclohexane and aldrin. The occurrence of these compounds in Greek surface waters can be attributed to intense agricultural activity as well as to transboundary pollution.

Formation of Haloforms in Drinking Water.- Formation of Brominated Organic Compounds in Chlorinated Drinking Water.- MX and Other Potentially Hazardous Chlorinated By-Products.- Ozonation By-Products.- Fate and Transport of Haloforms in Water Distribution Systems.- Health Effects of Haloforms in Drinking Water and Strategies for Their Control.- Analytical Methods for Determination of Haloforms in Drinking Water.- Occurrence and Regulation of Chlorination By-Products in Drinking Water.

The occurrence of volatile organic compounds (VOCs) was studied in river water, lake water, seawater and treated wastewater in Greece from October 1998 to September 1999. The determination of 41 VOCs was performed with a Purge and Trap–Gas Chromatography–Mass Spectrometry method. Samples were collected seasonally from 10 rivers, seven lakes, three gulfs and four wastewater treatment plants. In surface water samples, 15 VOCs were detected. In wastewater samples, occurrence of 31 VOCs was observed. The results suggest that not only agricultural and industrial activity within the Greek territory, but also transboundary pollution deriving from neighbouring countries consist important sources of VOCs in surface waters of Greece. However, the measured concentrations did not in any case exceed the guideline values proposed by the EC.

Acidic methanol esterification followed by gas chromatography (GC) with electron capture detection (ECD) was applied for the determination of the nine haloacetic acids in water. The main advantage of this method is the use of acidic methanol as the derivatization agent instead of the hazardous diazomethane. The recoveries, estimated at concentrations ranging from 0.5 to 30 μg/l, are high for eight of the nine haloacetic acids, with the only exception being monochloroacetic acid. However, problems with this compound have been reported with diazomethane derivatization methods as well. The detection limits of the method range from 0.01 to 0.2 μg/l.

Comparison of four methods including liquid-liquid extraction (LLE), direct aqueous injection (DAI), purge and trap (PAT) and head space (HS) were carried out in this work for determination of volatile organic compounds (VOCs) including trihalomethanes (THMs) in drinking water. This comparison is made especially to show the advantages and disadvantages and specifically the different detection limits (DL) that can be obtained for a given type of analysis. LLE is applicable only for determination of the THMs concentrations, while DAI, PAT, HS methods with different DL each of them are applicable for all VOCs, with PAT to be the most sensitive. Sampling apparatus and procedure for all these methods except of PAT are very simple and easy, but possible disadvantages for LLE and DAI are the low sensitivity and especially the detection only of THMs with LLE.

An investigation into the occurrence of volatile organic compounds (VOCs) was conducted for a period of two years in the surface waters of Northern Greece. Samples from four rivers and five lakes were taken seasonally and analyzed for VOCs. The analysis has been performed by purge-and-trap (PAT) gas chromatographic-mass spectrometric (GC-MS) technique. The most commonly encountered VOCs in surface waters were chloroform, carbon tetrachloride, trichloroethylene, dichlorobromomethane, tetrachloroethylene, and chlorodibromomethane.

The priority substances of List I, 76/464/EEC Directive, some of which belong to the new Water Framework Directive 2000/60/EC, have been monitored in the surface waters of Greece through the developed network of 53 sampling stations. The analytical methods used for the determination of these substances included Purge and Trap-Gas chromatography-Mass spectrometry for volatile and semivolatile organic compounds, Gas Chromatography-Electron Capture Detection for organochlorine insecticides, High Performance Liquid Chromatography for pentachlorophenol and Atomic Absorption Spectrometry for metals. The results have shown the presence of several priority substances in Greek surface waters, in most cases at concentrations well below the regulatory limits. However, non-compliance was observed for a limited number of compounds. The monitoring network and the analytical determinations have to be expanded to more water bodies and more priority substances, in order to safeguard the quality of Greek surface waters.