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Papers by Emmanouela Remoundaki

$Research paper thumbnail of Dry deposition of mineral aerosol particles in the marine atmosphere: significance of the large-size fraction$

Paleoclimatology and Paleometeorology: Modern and Past Patterns of Global Atmospheric Transport, 1989

Science of the Total Environment, 2011

The influence of Saharan dust on the air quality of Southern European big cities became a priorit... more The influence of Saharan dust on the air quality of Southern European big cities became a priority during the last decade. The present study reports results on PM(10) monitored at an urban site at 14 m above ground level during an intense Saharan dust transport event. The elemental composition was determined by Energy Dispersive X-ray Fluorescence Spectrometry (EDXRF) for 12 elements: Si, Al, Fe, K, Ca, Mg, Ti, S, Ni, Cu, Zn and Mn. PM(10) concentrations exceeded the EU limit (50 μg/m(3)) several times during the sampling period. Simultaneous maxima have been observed for the elements of crustal origin. The concentrations of all the elements presented a common maximum, corresponding to the date where the atmosphere was heavily charged with particulate matter permanently for an interval of about 10h. Sulfur and heavy metal concentrations were also associated to local emissions. Mineral dust represented the largest fraction of PM(10) reaching 79%. Seven days back trajectories have shown that the air masses arriving over Athens, originated from Western Sahara. Scanning Electron Microscopy coupled with Energy Dispersive X-ray analysis (SEM-EDX) revealed that particle agglomerates were abundant, most of them having sizes <2 μm. Aluminosilicates were predominant in dust particles also rich in calcium which was distributed between calcite, dolomite, gypsum and Ca-Si particles. These results were consistent with the origin of the dust particles and the elemental composition results. Sulfur and heavy metals were associated to very fine particles <1 μm.

Atmospheric Environment. Part A. General Topics, 1991

AMtraet--Daily 24-h aerosol samples have been collected at a coastal location in northwestern Cor... more AMtraet--Daily 24-h aerosol samples have been collected at a coastal location in northwestern Corsica, between February 1985 and March 1988. Total deposition has been sampled between February 1985 and October 1987 with a time span of about 15 days.

Water, Air, & Soil Pollution, 2010

Humic substances are characterized by a strong binding capacity for both metals and organic pollu... more Humic substances are characterized by a strong binding capacity for both metals and organic pollutants, affecting their mobility and bioavailability.

Water, Air, & Soil Pollution, 2013

ABSTRACT The evaluation of the contribution of natural sources to PM10 and PM2.5 concentrations i... more ABSTRACT The evaluation of the contribution of natural sources to PM10 and PM2.5 concentrations is a priority especially for the countries of European south strongly influenced by Saharan dust transport events. Daily PM2.5 concentrations and composition were monitored at an urban site at 14 m above ground level, at the National Technical University of Athens campus from February to December 2010. The typical dust constituents Si, Al, Fe, K, Ca, Mg, and Ti were determined by wavelength dispersive X-ray fluorescence spectrometry (WDXRF). Sulfur, a tracer of anthropogenic origin and major constituent of PM2.5, was determined by both WDXRF and ionic chromatography. The contribution of dust and sulfates in PM2.5 was calculated from the analytical determinations. An annual mean of 20 μg/m3 was calculated from the mean daily PM2.5 concentrations data. Twenty-two per cent of daily concentrations of PM2.5 reached or exceeded the EU annual target concentration of 25 μg/m3. The exceedances occurred during 13 short periods of 1–4 days. Back-trajectory analysis was performed for these periods in order to identify the air masses origin. From these periods, ten periods were associated to Saharan dust transport events. The most intense dust transport event occurred between February 17th and 20th and was responsible for the highest recorded PM2.5 concentration of 100 μg/m3 where the dust contribution in PM2.5 reached 96 %. The other dust transport events were less intense and corresponded to less pronounced enhancements of PM2.5 concentrations, and their contribution ranged from 15 to 39 % in PM2.5 concentrations. Air masses originated from northwest Africa while the influence of central Sahara was quite smaller.

Water Science and Technology, 1996

ABSTRACT

Tellus B, 1989

Beginning in 1985, a continuous aerosol sampling program has been undertaken at a coastal locatio... more Beginning in 1985, a continuous aerosol sampling program has been undertaken at a coastal location in northwestern Corsica. This site is 300 m above sea-level and at least 20 km from local pollution sources. It is exposed during 80% or more of the time to maritime air masses which have travelled over the western Mediterranean from southern, western and northern directions. Daily 24-h aerosol samples were collected on 0.4 pm pore size nuclepore filters from a 10 m high tower and analysed for Al, Si, P, S, K, Ca, Ti, Mn, Fe and Zn by X-ray fluorescence, and for Na, Cu and Pb by flameless atomic absorption. The data obtained up to now, from April 1985 to April 1986, show that the temporal variability of the concentrations displays 2 distinctive patterns. First, a seasonal pattern is observed for the elements of continental origin, either natural (e.g.. Al, Si) or anthropogenic (e.g., S, Pb). This pattern is inversely related to the frequency and amount of rainfall such that the highest concentrations are observed between May and October. Estimates based on these data indicate an average time of 2 days to reload that atmospheric environment with aerosol particles from continental sources. This seasonal pattern is not observed for locally produced sea-salt aerosol particles (index Na), whose concentration is related to local wind speed. Elements associated with mineral aerosol particles exhibit sporadic but intense concentration peaks that are superimposed on this general pattern. 20 of these events were recorded for the sampling period considered with their frequency being maximal in spring and summer. 3-D air-mass trajectories show that all these events are associated with transport of soil dust from Africa.

Industrial effluents containing Cr(VI) introduce significant toxicity in the environment. Treatme... more Industrial effluents containing Cr(VI) introduce significant toxicity in the environment. Treatment purposes are (i) the reduction of toxic chromium (VI) to the less toxic Chromium(III) and (ii) the precipitation of trivalent chromium. Metabolically mediated reduction of hexavalent chromium by microbial biomass is now well documented and, if applied successfully in an effluent treatment scheme, offers an efficient and low cost alternative avoiding the consumption of chemicals and energy. Positive results of complete biological reduction of hexavalent chromium are reported in the literature from the successful operation of pilot scale biological reactors. Organic compounds are often simultaneously present with chromium, in the solution under treatment, having three possible origins: (i) organic compounds co-existing with chromium in the effluent (e.g. leather tanning), (ii) organic compounds metabolically produced by the microbial biomass used for chromium (VI) reduction (EPS and oth...

Journal of Hazardous Materials, 2008

The characteristics of the biofilm and the solids formed during the operation of a sulphate-reduc... more The characteristics of the biofilm and the solids formed during the operation of a sulphate-reducing fixed-bed reactor, fed with a moderately acidic synthetic effluent containing zinc and iron, are presented. A diverse population of ␦-Proteobacteria SRB, affiliated to four distinct genera, colonized the system. The morphology, mineralogy and surface chemistry of the precipitates were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray (EDX). The XRD patterns observed are characteristic of amorphous solid phases. Peaks corresponding to crystalline iron sulphide, marcasite, sphalerite and wurtzite were also identified. SEM-EDX results confirm the predominance of amorphous phases appearing as a cloudy haze. EDX spectra of spots on the surface of these amorphous phases reveal the predominance of iron, zinc and sulphur indicating the formation of iron and zinc sulphides. The predominance of these amorphous phases and the formation of very fine particles, during the operation of the SRB column, are in agreement and can be explained by the formation pathways of metal sulphides at ambient temperature, alkaline pH and reducing conditions. Solids are precipitated either as (i) amorphous phases deposited on the bed material, as well as on surface of crystals, e.g. Mg 3 (PO 4 ) 2 and (ii) as rod-shaped solids characterized by a rough hazy surface, indicating the encapsulation of bacterial cells by amorphous metal sulphides.

Journal of Hazardous Materials, 2011

A batch upflow fixed-bed sulphate-reducing bioreactor has been set up and monitored for the treat... more A batch upflow fixed-bed sulphate-reducing bioreactor has been set up and monitored for the treatment of synthetic solutions containing divalent iron (100mg/L and 200mg/L), zinc (100mg/L and 200mg/L), copper (100mg/L and 200mg/L), nickel (100mg/L and 200mg/L) and sulphate (1700 mg/L and 2130 mg/L) at initial pH 3-3.5, using ethanol as the sole electron donor. The reactor has been operated at the theoretical stoichiometric ethanol/sulphate ratio. Complete oxidation of ethanol has been achieved through complete oxidation of the intermediately, microbially produced acetate. This is mainly attributed to the presence of Desulfobacter postgatei species which dominated the sulphate-reducing community in the reactor. The reduction of sulphate was limited to about 85%. Quantitative precipitation of the soluble metal ions has been achieved. XRD and SEM-EDS analyses performed on samples of the produced sludge showed poorly crystalline phases of marcasite, covellite and wurtzite as well as several mixed metal sulphides.