K. Fytianos

Occurrence and distribution of selected heavy metals in the surface sediments of Thermaikos Gulf, N. Greece. Assessment using pollution indicators.

Forty sediment samples and fifteen water samples were collected from the Gulf of Thermaikos and the Bay of Thessaloniki in order to determine the concentration of Zn, Cu, Pb and Cr and measure various seawater parameters. The level of pollution attributed to heavy metals was evaluated using several pollution indicators in order to determine anthropogenically derived sediment contamination. Enrichment Factors, Contamination Factors, Modified Contamination Degree, and Geoaccumulation Indexes for the sediments were used to assess and visualize using GIS. Association with adverse effects to aquatic organisms was determined, using the classification of the sediments according to the Sediment Quality Guidelines (SQGs). The highest metal levels were concentrated along the shoreline of the Bay of Thessaloniki, reflecting long-term exposure to anthropogenic activities. Enrichment Factors reveal the anthropogenic sources for chromium and lead. This is supported by separate Contamination Factors, the mean Contamination Degree, and the Geoaccumulation Index. The majority of the sediment samples can be occasionally and frequently associated to toxic biological effects, according to the effect-range classification for Zn, Cu and Pb. Based on the analysis of the overlying seawater columns it appears that under the present physicochemical conditions, dissolution of the accumulated metals from the sediments is unlikely. Although the total metal content in the sediments has decreased with time, the long-term effect of the industrial and urban activities in the area is still reflected in sediments from the gulf.

Speciation of elements in sediment samples collected at lakes Volvi and Koronia, N. Greece

A five-step sequential extraction procedure was applied for the determination of the distribution of seven elements (Cd, Pb, Cr, Cu, Mn, Zn, Fe) in sediment samples collected at two lakes, Volvi and Koronia, located in N. Greece. Samples were taken in two seasons, and the average concentration of the elements was calculated. The accuracy evaluated by comparing total trace metal concentrations with the sum of the five individual fractions proved to be satisfactory. Based on the results determined at one sampling point in Koronia and two sampling points along the lake Volvi, it seems that the two lakes have not yet been polluted. There were no significant changes in the individual seasonal concentrations of elements in this monitoring period. Cd, Pb, Cu and Cr are associated with the oxidizable, carbonates and residual fractions. Zn and Fe are associated with residual and reducible fractions. The metals that we most easily extracted in the samples analysed in both lakes are Pb, Cr, Cd, Cu and also Mn in the case of Koronia lake.

Leachability of heavy metals in Greek fly ash from coal combustion

A laboratory leaching test was used to determine the potential mobility of Pb, Cd, Cr, Cu, Zn, Ca, and Mn in fly ash samples, originated from four locations in Northern Greece, in order to assess their leachability when these wastes are disposed of. The cascade leaching test was used at liquid to solid ratios (LS) ranging between 5 and 100. All fly ash samples exhibited strong alkaline reaction, as indicated by pH values > 11.75 at LS = 10 and contact time of 10 min. In general, Ca showed the highest leachability and Mn the lowest in all samples. The percentage of leached amounts follows the trend Ca > Cd > Cr > Pb > Zn > Cu > Mn for samples from Kardia and Agios Dimitrios, Ca > Pb > Cd > Cr > Cu > Zn > Mn for the sample from Ptolemais, and Ca > Cu > Cd > Pb > Cr > Zn > Cu > Mn for the sample from Amideo. The six metals studied (Cd, Cr, Zn, Mn, and Cu) in fly ash from Amideo exhibited an increase in the leachate concentration as the leachant pH was reduced from 8 to 4. Pb followed by Cd exhibited the maximum extractability at all pH values. The least leachable components were Cu and Mn.

Vortex‐assisted liquid–liquid microextraction combined with gas chromatography‐mass spectrometry for the determination of organophosphate pesticides in environmental water samples and wines

A simple vortex-assisted liquid-liquid microextraction protocol followed by GC-MS is proposed for the determination of 12 organophosphate pesticides residues in environmental water samples and wines. The sample pretreatment employs the usage of low-density organic solvent. The parameters affecting the extraction efficiency (type and volume of organic extraction solvent, sample pH, ionic strength, extraction time, and centrifugation speed) were carefully examined. A mild emulsification process was involved by the addition of 40 μL toluene into 10 mL sample followed by sequential vortex-based agitation and manual shaking for 3 min. Following the extraction, the pesticide-rich organic solvent was recovered by centrifugation at 4000 rpm for 5 min. A fraction of the floated toluene was then collected and analyzed by GC-MS in SIM mode. Under the optimized conditions, the enrichment factor ranged between 65 and 389. Satisfactory linearity was observed for all pesticides tested with correlation coefficients higher than 0.9945 while the LODs were in the range of 2-11 ng L(-1) . The main advantages of the proposed method are the simplicity of operation, rapidity, low cost, and high sensitivity.

Fenton and Fenton-like oxidation of pesticide acetamiprid in water samples: Kinetic study of the degradation and optimization using response surface methodology

The aims of this study were (a) to evaluate the degradation of acetamiprid with the use of Fenton reaction, (b) to investigate the effect of different concentrations of H2O2 and Fe(2+), initial pH and various iron salts, on the degradation of acetamiprid and (c) to apply response surface methodology for the evaluation of degradation kinetics. The kinetic study revealed a two-stage process, described by pseudo- first and second order kinetics. Different H2O2:Fe(2+) molar ratios were examined for their effect on acetamiprid degradation kinetics. The ratio of 3 mg L(-1) Fe(2+): 40 mg L(-1) H2O2 was found to completely remove acetamiprid at less than 10 min. Degradation rate was faster at lower pH, with the optimal value at pH 2.9, while Mohr salt appeared to degrade acetamiprid faster. A central composite design was selected in order to observe the effects of Fe(2+) and H2O2 initial concentration on acetamiprid degradation kinetics. A quadratic model fitted the experimental data, with satisfactory regression and fit. The most significant effect on the degradation of acetamiprid, was induced by ferrous iron concentration followed by H2O2. Optimization, aiming to minimize the applied ferrous concentration and the process time, proposed a ratio of 7.76 mg L(-1) Fe(II): 19.78 mg L(-1) H2O2. DOC is reduced much more slowly and requires more than 6h of processing for 50% degradation. The use to zero valent iron, demonstrated fast kinetic rates with acetamiprid degradation occurring in 10 min and effective DOC removal.

Partitioning of heavy metals into selective chemical fractions in sediments from rivers in northern Greece

Abstract A five-step sequential extraction technique was used to determine the chemical association of heavy metals (Pb, Cd, Cu, Fe, Mn, Zn, Cr) with major sedimentary phases (exchangeable cations, easily reducible compounds, organic sulfidic phases, carbonates and residual components) in samples from rivers in northern Greece (Axios and Aliakmon). From the obtained data it can be seen that the surplus of metal contaminants introduced into the aquatic system from anthropogenic sources usually exists in relatively unstable chemical forms. A high proportion of the elements studied remains in the residual fraction for the Axios river and in the organic fraction for the Aliakmon. Most of the non-residual portion is bound to ferromanganese oxides and to organic matter.

Photochemical decomposition of carbamate pesticides in natural waters of northern Greece

Abstract The photochemical decomposition of the carbamate pesticides carbofuran, carbaryl and thiram was examined in natural waters of northern Greece under the influence of solar and UV ( λ > 290 nm) radiation. Different major photoproducts were detected by GC/MS. The result of continuous irradiation was almost total degradation of the pesticides examined.

Photo-Fenton decomposition of β-blockers atenolol and metoprolol; study and optimization of system parameters and identification of intermediates

Active pharmaceutical compounds reach the wastewater treatment plants mainly through excretion and improper disposal, and, because of insufficient treating methods, they end up to surface water or even potable water in some cases. Atenolol and metoprolol are β-blockers, members of cardiovascular pharmaceuticals group. They are generally used in the treatment of disorders such as hypertension, angina and arrhythmias. They have been in long-term use in Europe and North America, and they have also been detected in the aquatic environment. In this study the degradation of atenolol and metoprolol in aqueous solutions by means of the photo-Fenton reaction was investigated. The purpose of this study was: (i) to investigate the influence of the concentrations of iron and hydrogen peroxide, by means of central composite design, (ii) to study the degradation kinetics in aqueous solutions, (iii) to evaluate the mineralization and the toxicity evolution of the target compounds and (iv) to identify the degradation products. It has been found that increase of iron and hydrogen peroxide concentration accelerate the degradation of atenolol and metoprolol, while the kinetics of the process can be characterized as pseudo-first order. In general the photo-Fenton method has proved to be effective in decomposing and mineralizing the target compounds. The determination of the by-products formed during the degradation using LC-MS/MS equipment and the evaluation of the toxicity of the treated solution in different stages of the process would offer significant, innovative information regarding the treatment of water and wastewater containing active pharmaceutical compounds, especially of the β-blocker group.

Assessment of the Quality Characteristics of Pinios River, Greece

The results of a one-year detailed water quality study of the Pinios river are presented. Physicochemical parameters (pH, conductivity, DO) did not show significant differences neitherbetween sampling sites, nor between sampling periods. Nutrients(nitrogen and phosphorus compounds) showed temporal variationsprobably caused by seasonal variations in runoff nutrient fromweather events. Heavy metals (Pb, Cd, Cr, Cu, Ni) were determinedin the dissolved fraction and the variations observed were related to the geology of the examined area and the influence from anthropogenic sources. Statistical analysis of variance ofthe most important chemical parameters and heavy metals showedsignificant variation between sampling periods, but insignificantones between sampling sites.

Determination of non-ionic surfactants (polyethoxylated-nonylphenols) by HPLC in waste waters

High Performance Liquid Chromatography (HPLC) for the quantitative determination of nonylphenol polyethoxylates (NPE) in wastewater is described. The ethoxy chain length distribution was performed by normal phase HPLC using a UV detector. Two techniques for the isolation of APE from wastewater were compared: gaseous stripping into ethyl acetate to extract the analytes from the samples, and a column method. The mean values of influents and effluents were 1406 ~tg/L and 62 I-tg/L respectively. The removal of NPE ranged from 92 to 97%.