Comparative evaluation of river chemical status based on WFD methodology and CCME water quality index.

The Water Framework Directive (WFD) methodology, proposed by the Ministry of Environment and Energy of Greece (WFD-MEEG), and the Canadian Council of Ministers of Environment Water Quality Index (CCME-WQI) are comparatively applied to evaluate the chemical status of a major transboundary river. Water quality parameters were monitored at 11 sites along the main stream of the river and its main tributaries, and at five sites in the reservoirs, on a monthly frequency, in the period from May 2008 to May 2009. Water temperature (T), dissolved oxygen (DO), pH, and electrical conductivity (EC) were measured in-situ, while water samples were collected for the determination of total suspended solids (TSS), biochemical oxygen demand (BOD), chemical oxygen demand (COD), nitrite-, nitrate- and ammonium-nitrogen, total Kjeldahl nitrogen (TKN), ortho-phosphates (OP), total phosphorus (TP), and chlorophyll-a (Chl-a). The water samples were also analyzed for the determination of seven heavy metals (i.e., Cd, Pb, Hg, Ni, Cr, Cu, Zn) and 33 priority substances, as listed in Annex II of EU Directive 2008/105/EC. The results showed that the physicochemical parameters (i.e., T, DO, pH, EC, inorganic nitrogen, TKN, OP, TP, TSS, and Chl-a) were within the natural range. The mean concentration of the measured heavy metals did not exceed the limits set by WHO (2003, 2017) for drinking water. Regarding the priority substances, some of them (i.e., anthracene, fluoranthene, and polyaromatic hydrocarbons) were measured in various stations at higher concentrations than the Annual Average Environmental Quality Standards (AA-EQS). Based on the WFD-MEEG methodology, the river water was in the 'good' quality class, while according to CCME-WQI the river quality ranged from 'marginal' to 'good' category. It seems that CCME-WQI is stricter than WFD-MEEG but could be a WQI appropriate for use.

Evaluating the photocatalytic treatment of stevioside by TiO2 in different aqueous matrices and identification of transformation products.

The present study reports the photocatalytic transformation of stevioside, under simulated solar irradiation using TiO2 as a photocatalyst. As a tool of investigating the effect of various aqueous matrices, as well as, the initial stevioside concentration on the variation of the photocatalytic efficiency, a fully nested experimental design was employed. A significant impact on the degradation rate of the sweetener was observed: degradation rate decreases in the order distilled water>river water>lake water, attributed to the increased natural organic matter content of the respective natural water samples. Moreover, the investigation has involved the identification of intermediate compounds, as well as the assessment of mineralization and toxicity evaluation. More than one hundred unknown transformation products, most of them in the form of several isobaric species, were identified. By employing accurate mass determination, we were able to attribute an empirical formula to each species and through MSn analyses we were capable to distinguish several isobaric species. The overall transformation mechanism was assessed and involved the hydroxylation/oxidation of the molecule and the subsequent loss of the glucose units bound to the parent compound.

Assessment of the abatement of acelsulfame K using cerium doped ZnO as photocatalyst.

In the present study, we investigated the possibility to abate Acesulfame K, a persistent emerging contaminant, in aqueous media using zinc oxide based materials. For this purpose, bare and Ce-doped zinc oxide was prepared via an easy and cheap hydrothermal process using different cerium salts as precursors. Their photocatalytic performance was evaluated in different media, namely ultrapure and river water under both UV-vis and visible light. Commercial TiO2 P25 was also employed and used as a reference photocatalyst for comparison purposes. The obtained results pointed out that cerium doped zinc oxide composites exhibit higher performance than TiO2 P25, especially under visible light and in the presence of organic matter, when the activity of the latter is greatly depressed. In particular, ZnO doped with cerium (1%) was the most effective material, and could be a promising alternative to TiO2 P25, especially in the treatment of natural waters.

Photocatalytic degradation of the fungicide Fenhexamid in aqueous TiO(2) suspensions: identification of intermediates products and reaction pathways.

Liquid-chromatography interfaced with time-of-flight mass spectrometry (LC-TOF/MS) was used to separate and characterize the transformation products arising from TiO(2)-photocatalytic degradation of the fungicide Fenhexamid (FEX) in aqueous solution under simulated solar irradiation. Prior to identification, irradiated solutions of FEX (10mgL(-1)) were concentrated by solid-phase extraction. Assignments of the mass spectra ions were aided by elemental composition calculations, comparison of structural analogues and available literature, and acquired knowledge regarding mass spectrometry of related heterocyclic compounds. The primary transformation intermediates identified were hydroxyl and/or keto-derivatives. Several positional isomers are typically produced as a consequence of the non-selectivity of the ()OH radical attack. Moreover, products resulted from the cleavage of the amide and NH-dichlorophenol bonds were formed. Finally, cyclic - benzo[d]oxazole intermediates are also formed through an intramolecular photocyclization process and cleavage of halogen - carbon bond. In the case of the hydroxy and/or keto-derivatives, the generic fragmentation scheme obtained from the interpretation of the ESI-TOF-MS data cannot be diagnostic to precisely localize the position of the entering substituent on the FEX molecule, and thus to characterize all its possible oxygenated derivatives by assigning a plausible structure with confidence. On the basis of identified products different pathways of photocatalytic degradation of FEX were proposed and discussed.

Particle-associated polycyclic aromatic hydrocarbons near power plants as determined by large volume injection--GC/MS.

PM(10) and PM(2.5) samples were collected at two locations in the heavy industrialized prefecture of Kozani, in North-western Greece; in the open-cast mines of Klitos area and in the urban area of city of Kozani. The samples were collected by the use of low volume samplers, for a period of 1 year every 6 d. An analytical method has been adapted for determining 16 particle-bound polycyclic aromatic hydrocarbons (PAHs) in PM(10) and PM(2.5). Samples were collected on poly-tetra-fluorinated-ethylene (PTFE) filters using low volume samplers, considered to be ideal for trapping various organic pollutants including PAHs. The extraction has been made in two stages. Firstly, by reflux and then by using ultrasound bath. Chromatographic analysis has been carried out by GC/MS with programmable temperature vaporizers (PTV) injector and large volume injection (LVI) technique. Mean daily concentrations of B[a]Py in PM(10)-bound particles were 0.57 ng m(-3) in Kozani and 0.58 ng m(-3) at Klitos, while in PM(2.5)-bound PAHs were 0.35 ng m(-3) and 0.30 ng m(-3) respectively. We were able to verify the sources of PAHs by the use of diagnostic ratios, which indicate oil or/and coal burning as the, possible, major PAHs pollutant source(s).

Identification of photocatalytic degradation products of bezafibrate in TiO(2) aqueous suspensions by liquid and gas chromatography.

In the present study the photocatalytic degradation of bezafibrate (BZF), a lipid regulator agent, has been investigated using TiO(2) suspensions and simulated solar light. The study focus on the identification of degradation products (DPs) using powerful analytical techniques such as liquid chromatography time of flight mass spectrometry (LC-TOF-MS), gas chromatography mass spectrometry (GC-MS), and high-performance liquid chromatography with diode-array detection (HPLC-DAD). Each technique provided complementary information that enabled the identification of 21 DPs. Accurate mass measurements obtained by LC-TOF-MS provided the elucidation of 17 DPs. Mass errors lower than 2mDa, allowed the assignment of empirical formula for the mayor DPs to be determined confidently. Three DPs were identified by GC-MS through the structural information provided by full scan mass spectra obtained by electron impact (EI) ionization and two more by HPLC-DAD by comparing the retention times (t(R)) and the UV spectra of the unknown DPs with those of commercial standards. Based on this by-product identification a possible multi-step degradation scheme was proposed. The pathways include single or multiple hydroxylation of BZF with subsequent phenoxy ring opening and the cleavage of the amide and ether bonds.

A multispecies approach for monitoring persistent toxic substances in the Gulf of Gdansk (Baltic sea).

Bivalve mussels are usually used for biomonitoring persistent toxic substances (PTS) in coastal ecosystems. Nevertheless, these organisms, which live attached on hard substrates, can be found along the sandy coasts only on human manufactured products. In this work different species collected in the Gulf of Gdansk were compared to evaluate their suitability for monitoring PTS pollution at a local scale. The clam Mya arenaria seems to represent an excellent indicator of sediment pollution, mainly for organotin compounds which are selectively bioaccumulated. Organochlorine compounds are bioaccumulated in the different species mainly in function of their lipid body burden. Habitat conditions (salinity, substrate, pollution), however, strongly limited the occurrence of different species in the sampling sites; the most ubiquitous species, the common shrimp Crangon crangon, resulted therefore the most suitable to be used for the comparison of PTS pollution in this aquatic environment. Although the blue mussel (Mytilus trossulus) was confirmed to be a very useful sentinel species to compare pollution level inside and outside the Gulf of Gdansk, we recommend the use of other species to give a more detailed picture of the pollution situation in coastal areas.

PCB levels and accumulation patterns in waterbird eggs and in their prey at Lake Kerkini, a north-eastern Mediterranean wetland of international importance.

Seven "target" PCB levels were determined and compared in waterbird eggs, in their prey, and in water at Lake Kerkini, northern Greece, to investigate PCB bioaccumulation patterns and to define the best bioindicator of target PCBs for this area. PCBs were analysed from eggs of Phalacrocorax carbo, Podiceps cristatus, Ardea cinerea, Egretta garzetta, and Nycticorax nycticorax and from prey types Alburnus alburnus, Rutilus rutilus, Lepomis gibbosus. Carassius auratus, and Rana sp. PCBs analysed were detected in all bird eggs, prey, and water but contamination patterns differed among these sample types. The lipid-corrected geometric means of the congeners analysed were significantly different among most bird species and among some prey species. PCB congeners 118, 138, 153, and 180 accounted for around 80% of the total PCB contamination in bird egg samples. Percent congener concentrations of high-chlorinated PCBs tended to increase from water through prey to most bird egg samples whereas the low chlorinated PCBs (28 and 52) decreased. Bioaccumulation factors (BAFs) also exhibited an increasing trend for higher chlorinated PCBs from prey types to bird eggs. The greatest BAFs of six of the congeners were shared between Phalacrocorax carbo and Ardea cinerea. Among prey, the BAFs of four PCBs were highest in Lepomis gibbosus. Biomagnification factors varied between 1.01 and 39.57. In contrast to low chlorinated PCBs, high chlorinated congeners biomagnified considerably through fish prey. The highest biomagnification took place in Phalacrocorax carbo. No relationship was found between the lipid content of samples and BAFs of PCBs probably due to biotransformation differences of the congeners in the biota sampled. Due to the greatest PCB concentrations especially of the higher chlorinated PCBs in the eggs of Phalacrocorax carbo and its considerable bioaccumulation tendencies, it is proposed as the best PCB biomonitor of target PCBs at Lake Kerkini. Lepomis gibbosus had the highest concentrations of most congeners and exhibited the greatest bioaccumulative properties among prey and can be used as an alternative biomonitor.

Measurement uncertainty arising from trueness of the analysis of two endocrine disruptors and their metabolites in environmental samples. Part I: ultrasonic extraction from diverse sediment matrices.

The validation of preconcentration strategies for the simultaneous determination of two endocrine disrupting compounds (EDCs) and their metabolites present in the aquatic environment including natural waters and freshwater sediments as well as the estimation of uncertainty arising from trueness using fully nested experimental designs are presented in a series of two papers. In this work, we present Part I of our ongoing study, the validation of an analytical method based on ultrasonic extraction of the target analytes from various freshwater sediments and the estimation of the method measurement uncertainty. The selected endocrine disruptors included two widely used herbicides, diuron (1-(3,4-dichlorophenyl)-3,3-dimethylurea) and linuron (3-(3,4-dichlorophenyl)-1-methoxy-1-methylurea) and their common degradation products namely, 3,4-dichloroaniline (3,4-DCA), 1-(3,4-dichlorophenyl) urea (DCPU) and 1-(3,4-dichlorophenyl)-3-methylurea (DCPMU). A high-performance liquid chromatography system coupled to UV-diode array detector (HPLC/UV-DAD) was used for the target analytes quantification. A fully nested experimental design was applied to study the measurement uncertainty arising from trueness by estimating proportional bias (in terms of recovery). The overall recoveries, that is, those determined by the nested experiments were in the range of 59.5-85.1%, except 3,4-DCA for which a low overall recovery of 29.0% was observed. The analytical method was shown to be linear over the studied range of concentrations (5-100 microg/kg), exhibiting satisfactory repeatability and reaching limits of detection usually in the 0.6-4.6 microg/kg range on dry sediment basis. The method used permitted the determination of the target EDCs and their metabolites in sediment samples collected from selected study stations in the region of Epirus (N.W. Greece) at the concentration levels demanded by current legislation.

Measurement uncertainty arising from trueness of the analysis of two endocrine disruptors and their metabolites in environmental samples. Part II. Solid-phase extraction from environmental natural waters.

In this work, a preconcentration method for the simultaneous determination of the endocrine disrupting chemicals (EDCs), diuron (1-(3,4-dichlorophenyl)-3,3-dimethylurea), and linuron (3-(3,4-dichlorophenyl)-1-methoxy-1-methylurea), as well as their metabolites DCPU (1-(3,4-dichlorophenyl) urea), DCPMU (1-(3,4-dichlorophenyl)-3-methylurea) and 3,4-DCA (3,4-dichloroaniline), present in natural waters was optimized and validated. Water was subjected to solid-phase extraction (SPE) and the influence of several experimental variables affecting the extraction efficiency of the target analytes was studied, including the sorbent material, elution solvents, pH and breakthrough volume, as well as some solution parameters that is, ionic strength and organic matter content. A high-performance liquid chromatography system coupled to UV-diode array detector (DAD) was used for the target analytes quantification at the optimum conditions described in Part I. The fully nested experimental design, adapted to the new experimental parameters, was used to study the measurement uncertainty arising from trueness by estimating proportional bias (in terms of recovery). The overall recoveries of the target analytes were in the range of 71.6-90.2%, except 3,4-DCA for which a low overall recovery of 51.4% was obtained. The analytical procedure was shown to be linear over the studied range of concentration (25-400 ng/l), exhibiting satisfactory repeatability and reaching limits of detection in the 1.3-11.2 ng/l range for all, quite different in nature, water types. The SPE method was further applied for the determination of the selected EDCs and their metabolites in water samples taken from selected study stations in the region of Epirus (N.W. Greece) corresponding to the sediment samples locations (Part I).

Aqueous phototransformation of zinc pyrithione Degradation kinetics and byproduct identification by liquid chromatography--atmospheric pressure chemical ionisation mass spectrometry.

The photochemical behavior of the antifouling agent zinc pyrithione (ZnPT) was studied in aqueous media of different composition under simulated solar irradiation using a xenon light source. The influence of important constituents of natural water (dissolved organic matter and nitrate) was also examined using a multivariate kinetic model. It was found that photodegradation proceeds via a pseudo first-order reaction. Kinetic experiments were monitored by LC-MS and photolytic half-lives ranging between 9.2 and 15.1 min have been observed. The increasing concentration of dissolved organic matter (DOM) accelerates the photolysis reaction, while the effect of nitrate ions was also positive since it increased the degradation rate, but to a lesser extent. Irradiation of the aqueous ZnPT solutions gave rise to several transformation products that were isolated by means of solid-phase extraction using poly(styrene-divinylbenzene) extraction disks. These byproducts were identified using liquid chromatography-atmospheric pressure chemical ionisation mass spectrometry. Besides 2-pyridinesulfonic-acid, other degradation products formed included pyridine-N-oxide, 2-mercaptopyridine, 2,2'-dithiobis(pyridine-N-oxide), 2,2-dipyridyl disulfide and the pyridine/pyrithione mixed disulfide, 2,2'-dithiobispyridine mono-N-oxide (PPMD).

Some chemical contaminant of surface sediments at the Baltic Sea coastal region with special emphasis on androgenic and anti-androgenic compounds.

Androgenic and anti-androgenic compounds including p,p'-DDE, Diuron, Linuron, Fenarimol, Vinclozolin, 1-(3,4-dichlorophenyl) urea (DCPU), 1-(3,4-dichlorophenyl)-3-methylurea, (DCPMU), tributyltin (TBT) and triphenyltin (TPT) and their metabolites (DBT, MBT, DPT, MPT) as well as metallic elements (Ni, Cu, Zn, As, Cd, Pb, Co, Tl, Cr, Fe, Mn, Al, K, Mg, Na, Ca, Ba, Ti, Sn), PAHs (16 indicator compounds), DDTs and PCBs have been quantified in top layer (0-10 cm) of up to 37 surface sediment samples collected from several sites in costal zone of the Gulf of Gdansk, an inland freshwater area of Brdyujscie in Poland and the tidal flats of the Norderney Island, Wadden Sea in 2002-2003. These sites differed in the degree of anthropogenic activities, including chemical pollution and related impact on biota. Especially in sediments near shipyards, ship repair facilities, harbours, other industrial activities or close to municipal sewage treatment plant outlets butyltins, PAHs and some metallic elements were found at high concentrations. Diuron, Linuron and DCPMU were detected at a few sites, Fenarimol only once, while Vinclozolin and DCPU were not detected. DDT concentrations in the sediments from the Gdansk and Gdynia region of the Gulf show a stepwise decrease following the ban for production and use, while diffusion of PCBs at some industrial sites seems to continue. Elevated PAH concentrations in sediments seem to be mainly due to pyrogenic and less to mixed pyrogenic and petrogenic sources, while for a few sites rather petrogenic sources dominated. The reference sites in the Norderney Island, Wadden Sea showed similar or slightly higher loads of DDTs, BTs, PAHs, PCBs and metallic elements when compared to sediments from the least contaminated sites in the coastal Gulf of Gdansk area, while phenyltins were not detected at both spatially distant European areas.

Study of the removal of dichlorvos and dimethoate in a titanium dioxide mediated photocatalytic process through the examination of intermediates and the reaction mechanism.

The photocatalytic oxidation of two selected organophosphorous insecticides (dichlorvos and dimethoate) has been investigated. The aim of the study was the identification of the intermediates that are formed during photocatalytic treatment. Intermediate products from the slurry system were identified by means of solid-phase extraction (SPE) coupled to gas chromatography-mass spectroscopy techniques (GC-MS). Nine possible by-products were identified for dimethoate and three for dichlorvos. A proposed degradation pathway for each insecticide is presented, involving mainly oxidation and dealkylation reactions. The results demonstrated that some of the transient intermediates formed (oxon derivatives, disulfide, chlorinated fragments), were more toxic compared to parent compounds whereas most of them are less toxic than the parent compounds.

Persistent organochlorine contaminants in liver and fat of birds of prey from Greece.

The concentrations of persistent organic pollutants, such as DDT and its metabolites (DDTs), hexachlorocyclohexane isomers (HCHs), cyclodienes (Cycls), and polychlorinated biphenyls (PCBs), were measured in livers and subcutaneous fat tissues of six Accipitridae and four Falconidae bird species from different areas in Greece. This is the first report of persistent organochlorine (OC) pollutants in birds of prey tissues presented for Greece and the Eastern Mediterranean region. Accumulation patterns of OCs found in birds suggested that the predominant contaminants were p,p'-dichlorodiphenyldichloro-1,1-ethylene (DDE) and PCBs, whereas Cycls and HCHs occurred at low concentrations only. Concentration values of p,p'-DDE ranged from nondetected to 19,518.72 ng/g wet wt in livers and from nondetected to 2679.19 ng/g wet wt in fat. Total PCB levels ranged from 1.01 to 7419.43 ng/g and from 3.25 to 490.10 ng/g wet weight for liver and fat samples, respectively. Higher-chlorinated PCBs such as 118, 138, 153, and 180 predominated in both the liver and subcutaneous fat samples, a pattern comparable to that observed in birds from other European countries. No significant differences in mean concentrations of OCs are detected between species. Hepatic concentrations were in general higher than the fat concentrations showing depleted fat stores in most birds. Concentration ranges were also found in lower or similar levels to those reported for birds in other regions. Variation of OCs levels in bird tissues could be due to different causes of death, with a subsequent effect on body lipid levels, and different feeding and migration habits. The liver PCB levels reported in this study are below the concentrations currently believed to exert mortality or ecotoxicological effects. On the contrary, in some cases p,p'-DDE concentrations were higher than the reported effect values for birds of the same families and could be associated with sublethal effects.

Photolytic degradation of quinalphos in natural waters and on soil matrices under simulated solar irradiation.

The photochemical persistence of quinalphos, one of the most widely used organophosphorous insecticides, was investigated in a variety of environmental matrices such as natural waters and soils of different composition. Simulated solar irradiation was obtained using a xenon arc lamp (Suntest CPS+ apparatus) giving an irradiation intensity of 750 W m(-2) equivalent to a light dose per hour of irradiation of 2,700 kJ m(-2). The phototransformation rates were determined using solid-phase microextraction (SPME) and ultrasonic extraction (USE) coupled to GC-FTD, while the identification of photoproducts was carried out by GC-MS. In water samples, the degradation kinetics followed a pseudo-first-order reaction and photolysis half-lives ranged between 11.6 and 19.0 h depending on the constitution of the irradiated media. Dissolved organic matter (DOM) has a predominant retarding effect, while nitrate ions accelerated the photodegradation kinetics. In soil samples, the degradation kinetics was monitored on 1mm soil layer prepared on glass TLC plates. The kinetic behaviour of quinalphos was complex and characterized by a double step photoreaction, fast in the first 4h of irradiation followed by a slow degradation rate up to 64 h. The photolysis half-life of quinalphos was shorter in sandy soil compared to the rest of the soil samples, varying between 16.9 and 47.5 h, and showing a strong dependence on the composition of the irradiated media. Among the transformation products formed mainly through photohydrolysis and photoisomerization processes, some photoproduct structures were proposed according to their mass spectral information.

Accumulation profiles of persistent organochlorines in liver and fat tissues of various waterbird species from Greece.

Waterbirds are particularly subject to accumulation of persistent organic pollutants (POPs) that have been shown to constitute a major hazard for this group of birds. Liver and fat tissue from ten species belonging to the orders Ciconiformes (Ardeidae, Ciconiidae, Phoenicopteridae) and Pelicaniformes (Pelecanidae, Phalacrocoracidae) were used as bioindicators in order to assess environmental pollution by POPs (HCHs, DDTs, cyclodienes, PCBs) in Greek wetlands. To our knowledge, this is the first study on POPs in livers of water birds in Greece and Eastern Mediterranean area. The DDTs consisted mainly of p,p'-DDE with percentages over 60% in the great majority of the samples. The highest summation SigmaDDT concentrations were measured in the liver and subcutaneous fat of Phoenicopterus rubber and in Ardea purpurea liver (15565, 24706 and 10406 ng g(-1) wet weight, respectively). Low concentrations of cyclodienes (Cycls) and HCHs were detected occasionally and the contamination pattern of OCPs in most species of waterbirds followed the order summation SigmaDDTs> summation SigmaCycls> summation SigmaHCHs. Individual values of total PCBs reached the levels of 4468 and 3252 ng g(-1) wet weight, for Nycticorax nycticorax and Egretta garzetta samples respectively. Some of the recorded differences in organochlorine concentrations could be due to different causes of death, with a subsequent effect on body lipid levels. Organochlorine pesticides and PCBs residues were lower than those commonly associated with mortality and reduced reproductive success in most species. However, low level exposure to these contaminants may constitute one of the many stressors that in combination could adversely affect bird populations.

Screening method for organophosphorus insecticides and their metabolites in olive oil samples based on headspace solid-phase microextraction coupled with gas chromatography.

This work is focused on the effectiveness of headspace solid-phase microextraction (HS-SPME) for the analysis of nine organophosphorus (OPs) insecticides (dimethoate, diazinon, fenitrothion, malathion, fenthion, parathion ethyl, methyl bromophos, methidathion, ethion) and four metabolites (omethoate, malaoxon, fenthion sulfoxide and fenthion sulfone) residues in olive oil samples. The efficiency of six fibre types with different film thickness was compared. PDMS (100 microm) was found to be the most suitable fibre for the analysis of OPs in olive oils. Optimization of SPME conditions (stirring rate, extraction time, temperature, salt addition) was based on previous developed method in the laboratory that was enriched with additional analytes including major metabolites. In addition, the effect of the oil matrix on the pesticide recoveries was evaluated using spiked oil samples of different composition (acidity, fatty acids, triglycerides, sterols). It was found that only acidity and total amount of sterols are the main factors influencing the SPME efficiency. Matrix effects were compensated for, by using the internal standard method for the quantification of pesticides. The recoveries at three spiking levels were between 80% and 106% with R.S.D. (%) values below 10% in most cases. Good linearity (R2>0.985) was observed in the 0.025-0.50 mg kg(-1) concentration range with satisfactory R.S.D. (%) values of 4.5-10.4%. The method allowed detection of the tested compounds at concentrations below 0.010 mg kg(-1) with GC-FTD detection. In addition, intra- and inter-day precision was satisfactory (R.S.D. (%) <10%). The performance results confirm the usefulness of the proposed methodology for the analysis of OPs in olive oils. Moreover, the maximum residue limits required by European and international regulations can be attained without difficulty. Finally, the method was applied to 30 virgin olive oil samples from major olive production areas of Greece in the framework of an extended monitoring survey of OPs residues in olive oil. The most commonly found pesticides were fenthion, dimethoate and ethion in levels that did not exceed the MRLs.

Microbiological risk assessment of Agios Georgios source supplies in Northwestern Greece based on faecal coliforms determination and sanitary inspection survey.

The assessment of potential risks from microbiological contamination of drinking water supplies is of greatest concern to human health. The study involves the examination of water samples from Agios Georgios source that supplies the capitals, the major towns and several villages of Arta, Preveza and Lefkada prefectures, in Northwestern Greece. The study includes the sanitary inspection survey of the source and the microbiological examination of water samples on a monthly basis during the period February 1996-June 1999 except of Augusts (n=38). The microbiological risk assessment (MRA) approach of World Health Organisation (WHO) guidelines was applied to enhance the source protection. The faecal contamination of the source water was quantified using faecal coliforms (FC) as indicator bacteria. Microbiological analyses indicate that of the 38 samples analyzed the FC failure rate (positive samples) was 63.2% according to the limit set by the 98/83 directive of the European Union. The 36.8% of the source water samples was found in conformity with WHO guidelines, 42.1% of low risk, 21.1% of intermediate risk while there was not found samples of high or very high risk. Failure rates displayed a seasonal trend being greater during the winter, decreased during spring and autumn and lower during summer. This observation was explained partially by a significant positive relationship with the rainfall amount (r(Spearmann)=0.890, P=0.001). The sanitary inspection score was found 5/10 during the whole survey period that corresponds to an intermediate risk of source contamination. The color-code classification for FC contamination was found 36.8% A (blue, no risk), 42.1% B (green, low risk) and 21.1% C (yellow, intermediate risk). The previous risks were combined for the assessment of waterborne risk, which was determined as intermediate to high; therefore there is a need for high action priority. The potential remedial actions were also suggested in order to improve the source protection of such supplies.

Worldwide occurrence and effects of antifouling paint booster biocides in the aquatic environment: a review.

Organic booster biocides were recently introduced as alternatives to organotin compounds in antifouling products, after restrictions imposed on the use of tributyltin (TBT) in 1987. Replacement products are generally based on copper metal oxides and organic biocides. This ban has led to an increase in alternative coating products containing the above biocides. The most commonly used biocides in antifouling paints are: Irgarol 1051, diuron, Sea-nine 211, dichlofluanid, chlorothalonil, zinc pyrithione, TCMS (2,3,3,6-tetrachloro-4-methylsulfonyl) pyridine, TCMTB [2-(thiocyanomethylthio) benzothiazole], and zineb. Since 1993, several studies have demonstrated the presence of these biocides in European coastal environment as a result of their increased use. More recently, the presence of these biocides was also revealed in waters from Japan, United States, Singapore, Australia and Bermuda. This paper reviews the currently available data on the occurrence of these biocides in the aquatic environment. Some data dealing with the environmental fate, partitioning, behaviour and risk assessment of antifouling paint booster biocides are also reported in order to discuss the detected levels of contamination.

Aqueous photolysis of the sunscreen agent octyl-dimethyl-p-aminobenzoic acid. Formation of disinfection byproducts in chlorinated swimming pool water.

The photochemical behavior of the sunscreen agent octyl-dimethyl-p-aminobenzoic acid (ODPABA) was studied in different aqueous solutions and under different conditions. ODPABA photolysis was performed under laboratory conditions using a xenon light source and under natural sunlight conditions in sea, swimming pool as well as in distilled water. The influence of dissolved organic matter (DOM) on the degradation kinetics was also studied in the presence of various concentrations of humic acids (HA). The phototransformation was shown to proceed via pseudo-first-order reaction in all cases and the reaction rates followed the order: distilled water > swimming pool water > seawater, depending mainly on the presence of dissolved organic matter that retarded the photolysis reaction. Kinetic experiments were monitored with HPLC/UV-DAD and the half-lives (t 1/2) varied between 1.6 and 39 h in simulated solar irradiation and between 27 and 39 h in natural sunlight conditions. The product distribution during illumination was strongly dependent on the constitution of the irradiated media. Irradiation of the aqueous ODPABA solutions gave rise to several transformation products that were isolated by means of solid-phase extraction (SPE) and identified using GC-MS techniques. These were formed mainly through dealkylation and hydroxylation reactions and were detected in all aqueous solutions investigated. In the case of swimming pool water some additional byproducts were isolated and were tentatively identified as chlorinated intermediates, formed by the subsequent chlorination of the parent molecule as well as other intermediates.