Thriassion Plain Research Articles

Integrated Ecological Assessment of Heavily Polluted Sedimentary Basin within the Broader Industrialized Area of Thriassion Plain (Western Attica, Greece)

The Thriassion Plain, the Saronikos Gulf and Eleusis Bay, Western Attica in Greece, receive pressures from the enormous industrial activity, as well as the Athens metropolitan area and the Piraeus port. Therefore, it is considered as brownfield in the Eastern Mediterranean Sea. The multi-component industrial activity has impacted the soil, the groundwater of Thriassion Plain and the coastal marine sediments of the adjacent Eleusis Bay, part of Saronikos Gulf as well as a brackish lagoon, Koumoundourou Lake. The industrial activity is expressed by high contents of metals, and oil products. This study presents the pollution record of selected published papers that indicate the temporal evolution of legislated polluting compounds, supporting researchers to provide solutions and policy makers to focus on the whole spectrum of potential policy alternatives.

Atmospheric Concentrations and Health Implications of PAHs, PCBs and PCDD/Fs in the Vicinity of a Heavily Industrialized Site in Greece

Background: Thriassion Plain is considered the most industrialized area in Greece and thus a place where emissions of pollutants are expected to be elevated, leading to the degradation of air quality. Methods: Simultaneous determination of polycyclic aromatic hydrocarbons (PAHs), polychlorinated dibenzo-p-dioxins/dibenzofurans (PCDD/Fs), and polychlorinated biphenyls (PCBs) was performed in PM10 samples. SPSS statistical package was employed for statistical analysis and source apportionment purposes. Cancer risk was estimated from total persistent organic pollutants’ (POPs) dataset according to the available literature. Results: POPs concentrations in particulate matter were measured in similar levels compared to other studies in Greece and worldwide, with mean concentrations of ΣPAHs, ΣPCDD/Fs, dioxin like PCBs, and indicator PCBs being 7.07 ng m−3, 479 fg m−3, 1634 fg m−3, and 18.1 pg m−3, respectively. Seasonal variations were observed only for PAHS with higher concentrations during cold period. MDRs, D/F ratios, and principal component analysis (PCA) highlighted combustions as the main source of POPs’ emissions. Estimation of particles’ carcinogenic and mutagenic potential indicates the increased toxicity of PM10 during cold periods, and cancer risk assessment concludes that 3 to 4 people out of 100,000 may suffer from cancer due to POPs’ inhalation. Conclusions: Increased cancer risk for citizens leads to the necessity of chronic POPs’ monitoring in Thriassion Plain, and such strategies have to be a priority for Greek environmental authorities.

The Environmental Impact of a Complex Hydrogeological System on Hydrocarbon-Pollutants’ Natural Attenuation: The Case of the Coastal Aquifers in Eleusis, West Attica, Greece

The study area is the Thriassion Plain, an important area, in antiquity, surrounding the famous ancient town of Eleusis, 20 km west of Athens. The modern town and port and the entire area were heavily industrialized (1965–1995) coupled with unregulated urban and agricultural development. The presence of two crude oil refineries and other oil-related industries have strongly impacted the entire environment, including soils, waters and sediments of the broader area. The purpose of this work is to better understand how a multi-layered groundwater system affects the potential underground spread of certain fuel volatile compounds, namely the BTEX (benzene, toluene, ethylbenzene and total xylenes) as well as their attenuation after their direct or indirect release into the aquifer system. The spatial distribution of BTEX in groundwaters show that they were concentrated mainly in four rather restricted locations. Three of them were spotted, as expected, in the close vicinity of known pollution sources (a military airfield and two crude oil refineries). The other one corresponds to an abandoned site with no outstanding pollution sources where wells exist, eventually used for illegal dumping of oily wastes. It is important that the concentrations decrease significantly from autumn to spring. This decline could be characterized as natural attenuation, related to natural dilution phenomena and a flushing out of pollutants discharging through underwater springs to the sea during the rainy period (October to April). This, in turn, could be associated to the specific geological conditions affecting the hydrology, such as the unconsolidated non-permeable deposits and the multi layered formations of the area’s aquifers.

Advances in the Coastal and Submarine Groundwater Processes: Controls and Environmental Impact on the Thriassion Plain and Eleusis Gulf (Attica, Greece)

This study focuses on the hydrogeological conditions in the coastal (Thriassion plain) and submarine (Eleusis Gulf) environment of West Attica, Greece. Up to now, the predominant aspect for the Thriassion plain groundwater—hosted within the Neogene-Quaternary sediments—was its direct hydraulic contact with the seawater. Due to that, the coastal plain groundwater is strongly believed to be of brackish quality irrespective of the local hydrodynamic conditions. Our major goal is to evaluate the actual mechanism controlling the groundwater flow, the origin and distribution of saline water, and the existence of fresh groundwater in the submarine environment. We summarize the following: (1) groundwater of the Thriassion plain is partly discharged as an upwards leakage from deeper aquifers, (2) modern direct seawater intrusion is not possible in the Neogene-Quaternary sediments, and (3) fresh groundwater possibly exists below the sea floor of the Eleusis Gulf. The results may serve as hint of further research in groundwater resources below the Mediterranean Sea floor, and, consequently, a new perspective on water resource management could emerge.

Geochemical evolution of the Thriassion Plain groundwaters, Attica, Greece.

The geochemical evolution of groundwater in the coastal area of the Thriassion Plain, Attica, Greece, has been investigated using major and trace elements of chemical analyses. The groundwater of good quality (total dissolved solids TDS between 400 and 1100 mg/l) has been found in the Plio-Pleistocene sediments up to the depth of 90 m below sea level. Moreover, the existing contamination of groundwater in the Pleistocene-Holocene sediments possibly originates from the pumping of the old brackish water of the upper aquifers and the returns of the irrigation water as well as the possible occurrence of palaeo-seawater in the aquifers. A five-stage conceptual model is suggested for groundwater geochemical evolution from the main recharge area to the main discharge area. Limestone and dolomite dissolution in the recharge area leads to one end member of the Ca-Mg-HCO3 type. These waters evolve to Ca-Mg-Cl-HCO3 along their flow path possibly due to the dissolution of relics of evaporites, as well as mixing with seawater that is Na-Cl type, the other end member. Two more hydrogeochemical processes have also been identified; possibly gypsum, anhydrite, halite and fluorite dissolution; calcite, aragonite and dolomite precipitation.

The use of geochemical ratios in groundwater quality assessment: the case of the Thriassion Plain, Attica, Greece

This paper is an effort to assess the groundwater quality and the geochemical processes mainly using the Chadha’s diagram which classifies natural waters and documents the Piper and extended Durov diagrams. Chadha’s diagram is a useful tool to interpret groundwater geochemical processes because it is produced by simple spreadsheets excel files. The example of hydrochemical analyses were given from groundwater samples of the Thriassion Plain. To attend our objective, 38 groundwater samples were collected. Hydrochemical sections, XY diagrams, distribution maps of ionic ratios as well as the Gibbs diagrams were used to identify origin of salinity and the hydrogeochemical processes that have taken place. The Gibbs diagrams have shown that evapotranspiration (ET) and rock-water interaction play an important role to the increase of groundwater salinity. The interpretation of Chadha diagram highlights that the stratigraphic factors and especially the clay strata occurrence have isolated fresh groundwater from seawater. The abundant occurrence of clay deposits to the depth of the plain work as barriers to direct seawater intrusion. Good quality groundwater identified confirms the important role of clay strata. Reverse cation exchange, is the predominant geochemical process in the Thriassion Plain aquifers, whereas evapotranspiration (ET) and rock-water interaction play an important role to the increase of groundwater salinity.

Tectonic structure of Central-Western Attica (Greece) based on geophysical in vestigations-Preliminary results

In an effort to investigate the deep geological structure in the broader area of central-western Attica, that suffered severe damage during the destructive Athens earthquake of September 7th, 1999, the Department of Geophysics-Geothermics of the Faculty of Geology and Geoenvironment of Athens University, in collaboration with the Geodynamic Institute of National Observatory of Athens and the Department of Geological Sciences of Durham University, carried out a combined geophysical survey. For the first time in Attica, seismic and gravity geophysical methods were applied along profiles, in such an extensive scale. Within the framework of this investigation the following tasL· were accomplished: a) Three (3) seismic lines of about 30 kilometres of total length, two (2) in the area of Thriassion plain and one (1) along the Parnitha-Krioneri-Drosia-Ekali-Dionysos axis (Attica plain) and b) 338 gravity measurements distributed along eight (8) gravity profiles, four (4) of which in Thriassion plain, three (3) in Petroupoli-Aharnes-Thrakomakedones region (Attica plain) and one (1) along Parnitha-Krioneri-Drosia-Ekali-Dionysos axis (Attica plain). Preliminary results of the geophysical investigation combined with existing geological and tectonic data are presented in this paper. Significant variation in the elevation of the alpine basement has been detected, expressed by manifestation of low and high subsurface areas which are well correlated with existing fault zones. In the area of Thriassion plain the thickness of post-alpine sediments is estimated of a few hundred meters (<500 meters) and huge thickness of several hundred meters (-800 meters) of post-alpine sediments were detected in Thrakemakedones and Krioneri areas. The relief of alpine basement is more intense in fault zones areas, such as Thriassion plain (WNW-ESE), Pathitha and Kifissos (NE-SW) as well as along the fault zone outline the Fili and Aharnes graben and is covered by postalpine formations

CONTRIBUTION TO HYDRAULIC CHARACTERISTICS OF PLIO-PLEISTOCENE DEPOSITS OF THRIASSION PLAIN OF ATTICA

The geological structure of Thriassion Plain is generally complex and has been affected at different times by many tectonic activities. The last ones are the neotectonic, which caused horsts and grabens structures. Geologic and tectonic structures have influenced the hydrogeological conditions and the groundwater flow. Hydraulic characteristics of Plio-Pleistocene deposits differ throughout their extent. In this study, pumping tests in Plio-Pleistocene deposits are represented and the hydraulic characteristics transmissivity T, storativity S and hydraulic conductivity K are assigned. Pumping tests, in 8 totally wells, were conducted in the dry period. Methods as Cooper-Jacob’s, Theis’s, Papadopoulos Cooper’s and Neuman’s and last the Recovery method, are used to assign the hydraulic characteristics. These tests highlighted the Recovery method as the most reliable. Transmissivity T: 18-279.1 m2/d, storativity S: 2.5*10-3 3*10-2and hydraulic conductivity K: 0.4-25.1 m/d. Specific capacity is also determined ranging between 16-360 m3/d/m. This study contributes, essentially, in the approach of hydrogeological conditions of Thriassion Plain.

Origin of halogens and their use as environmental tracers in aquifers of Thriassion Plain, Attica, Greece

The processes that control halide concentrations in coastal aquifers of the Thriassion Plain in Greece include both natural and anthropogenic factors as follows: evapotranspiration, dissolution of evaporites, domestic sewage as well as dissolution of minerals containing fluoride. Groundwater monitoring data indicate that the Cl−/Br− mass ratio ranges between 43 and 1510. Ratios ranging round the value 292 are attributed to sea intrusion; 300–600 to domestic sewage; and 900–1510 to dissolution of evaporites. The evaporation of irrigated water plays an important role as well. Fluoride concentrations ranging from 0.1 up to 9.94 mg/l possibly originate from Holocene as well as Plio–Pleistocene sediments which contain organic material. It is also likely that fluoride originates from fluorite dissolution or comes from Palaeozoic-Middle Triassic volcano-sedimentary rocks which occur around the wider area and constitute the basement of the study area. In those rocks, the alteration of biotite to chlorite takes place under the influence of hydrothermal fluids, as the Thriassion Plain is close to South Aegean volcanic arc where volcanic activity exists.

Environmental Management Approaches and Water Resources in the stessed region of Thriassion, Greece

The present attempt has a two prong-emphasis. On the one hand it demarcates the physical, structural, social and economic parameters and the eliciting environmental problems in Thriassion Plain, the main industrial area of metropolitan Athens, Greece. On the other hand it attempts to delineate a framework of total unit management in terms of actions that may make possible the solution of long term pollution problems focusing on the whole spectrum of potential policy alternatives. Such an approach could contribute in presenting some options, for water resources management in particular and in general for natural resources management efforts, that may outline an environmental management framework necessary for a continuous, comprehensive and future oriented development of the area.

Biometeorological and air quality assessment in an industrialized area of eastern Mediterranean: the Thriassion Plain, Greece

Evidence that heat wave events are associated with poor air quality conditions and health hazards has become stronger in recent years. In this study, the impact of two heat wave episodes on human thermal discomfort and air quality is examined during summer 2007, in an industrial plain of eastern Mediterranean: the Thriassion Plain, Greece. For this purpose, two biometeorological indices-Discomfort Index (DI) and Heat Load (HL)-as well as an air quality index-Air Quality Stress Index (AQSI)-were calculated using data from seven measuring sites. A land-use map was procured in order to examine the effect of different land cover types on human thermal comfort. The results indicated high level of thermal discomfort and increased air pollution levels, while a significant correlation between the DI and the AQSI was identified.

A case of nighttime high ozone concentration over the greater Athens area

A cas e of abrupt and significant increase of surface ozone was examined, which is recorded during the night of October 9 th , 2003, over the area of the Thriassion Plain – Greece, being acco mpanied by the occurrence of a wind outbreak during the same period. As this increase cannot be explained by the ordinary diurnal evolution of tropospheric ozone concentration, the possibility of downward stratospheric ozone transport was investigated. It was indeed found that the case is associated with tropopause folding and subsequent stratospheric air intrusion in the upper troposphere over Greece. With the aid of mesoscale modeling, being also supported by the hydraulic theory, it was found that the intense wind outbreak is associated with the development of disturbances in the lee side of the neighbouring mountain ranges. These disturbances contribute to the free troposphere – atmospheric boundary layer interaction, facilitating the transportation of stratospheric air close to the surface, thus resulting to the observed tropospheric ozone increase. Zusammenfassung

Predicting photochemical pollution in an industrial area

In order to confront pollution events concerning the city of Elefsis, in the environmentally aggravated area of Thriassion Plain, an effort is undertaken to create a model forecasting maximal daily concentrations of NO(x) (NO(2)+NO), NO(2) and O(3). The data analyzed were obtained from the Bureau of Pollution Control and Environments Quality based in Elefsis. The model in question uses hourly values of the pollutants as well as meteorological data recorded at the center of the city of Elefsis from 1993 to 1999. Three fitting methods are utilized, namely ordinary least squares, piecewise, and quantile regression. The verification and reliability of the forecasting models are based on the measurements of the year 2000. The results are considered to be satisfactory, with the forecasted values following the general tendencies.

Influence of sea breeze flows on air pollution over the attica peninsula

In the frame of the APSIS project (Athenian Photochemical Smog Intercomparison of Simulations) simulations of the flow and the air pollution over the Attica Peninsula have been carried out. The simulations are performed with the model system KAMM/DRAIS for 25 May 1990, using the RADM gas-phase chemical mechanism. They show the influence of the sea breeze on the diurnal cycle of the NO, NO 2 and O 3 concentrations in the Greater Athens Area. The formation of ozone due to industrial emissions at the coast of the Thriassion plain and from the traffic emissions in the city of Athens leads to peak ozone concentrations of nearly 400 μg m −3 northeast of the centre of the city. Measurements of wind speed, wind direction and temperature support that the development of the sea breeze in the basin of Athens is well described by the model. The comparison between the measured and calculated concentrations shows at most of the stations a satisfying agreement.

An experimental study of nightime air-pollutant transport over complex terrain in Athens

The Thriassion plain is a heavily industrialized area to the west of the Athens basin, separated from it by Mount Aegaleo, a 468-m high ridge about 15 km long. Three field experiments were performed to determine the possibility of air pollutant transport into the Athens basin. Sulphur hexafluoride (SF 6) was released from one of the stacks of the Hellenic Oil Refineries, situated in the eastern part of the Thriassion plain, together with several releases of tetroons. These experiments revealed two mechanisms of air mass transport from the Thriassion plain, a daytime mechanism, when the air mass is transported along the Mount Aegaleo ridge and through the passage between Mount Aegaleo and Mount Parnitha to the north, and a nighttime mechanism, when transport occurs over Mount Aegaleo. SF 6 was released only during the night and although in all three occassions it reached the western suburbs of Athens, it did so by different simultaneous mechanisms. Furthermore its advection-diffusion once in the basin showed large variability, whose cause was the details of the flow field as it developed under the influence of the thermal stratification. The experiments demonstrate the complexity of the diffusion of air pollutants in complex terrain and the influence of both the details of the flow field and the stratification in determining the local ground-level concentrations. They also point out the need for simultaneous modelling of both factors, for the correct computation of pollution levels.