ENVIRONMENTAL IMPACT ASSESSMENT OF A METRO INFRASTRUCTURE FACILITY CONSTRUCTION BY MODELLING WATER AND SOIL POLLUTION

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1 Global NEST Journal, Vol 16, No X, pp XX-XX, 2014 Copyright 2014 Global NEST Printed in Greee. All rights reserved ENVIRONMENTAL IMPACT ASSESSMENT OF A METRO INFRASTRUCTURE FACILITY CONSTRUCTION BY MODELLING WATER AND SOIL POLLUTION GEORGE DIMITRIOU 1,2 1 Shool of Siene and Tehnology, Helleni Open University PAPADOPOULOU M.P 1,3,* 18 Aristotelous Parodos, Patra Engineering Geology Department ATTIKO METRO SA, Mesogion , Athens Shool of Rural and Surveying Engineering National Tehnial University of Athens 9 Iroon Polytehniou, Zografou 15780, Athens, Greee Reeived: 17/01/2014 Aepted: 21/07/2014 Available online: 24/07/2014 *to whom all orrespondene should be addressed: mpapadop@mail.ntua.gr ABSTRACT The onstrution of large infrastruture projets suh as highways, railroads, landfills, airports, harbours offers great soial-eonomi opportunities for the development of a region; it is also mainly responsible for the deterioration of natural environment in the greater areas where these projets are loated. The goal of environmental impat assessment (EIA) that is arried out before the onstrution of suh a projet is to propose measures and ations that will limit negative environmental impats during its onstrution and operation phases. The ommon pereption is that large sale infrastruture projets an only damage natural environment even though very strit environmental requirements are imposed by the Authorities. This was not the ase in Eleonas Attikis region in Greee where METRO failities were built. During the onstrution phase, hazardous solid wastes were found buried in the urban area where METRO failities (station, tunnel and depot) were loated, raising serious environmental issues in natural and human environment in the region. The protetion and restoration of environment in an unontrolled waste dumpsite require aurate estimation of subsurfae pollution extent and intensity. The sope of the present analysis is to map the ontamination in the aquifer of Eleona Attikis where METRO failities (station, tunnel and depot) were built. Numerial modelling approahes were used to estimate environmental impats of this projet to soil and water resoures in the greater region. The results have shown that the removal of buried solid wastes to onstrut METRO station and depot was ruial in order to eliminate negative impats in soil and subsurfae water resoures. An impat assessment of hazardous solid wastes buried for many years in the aquifer was also performed. The findings of this analysis proved that the implementation of a large infrastruture projet suh as the one in Eleona Attikis Greee was environmentally benefiial for the region. Keywords: Environmental impat assessment, soil and subsurfae water map pollution, METRO infrastruture faility, unontrolled solid wastes disposal, aquifer remediation ations, numerial modelling and pollution monitoring 1. Introdution Previous researh works have shown that implementation of large sale infrastruture works may ause hanges in the environmental onditions of a region. For that reason, an environmental assessment Dimitriou G. and Papadopoulou M.P. (2014), Environmental impat assessment of a METRO infrastruture faility onstrution by modelling water and soil pollution, Global NEST Journal, 16(X), XX-XX.

2 2 DIMITRIOU and PAPADOPOULOU should be undertaken for a) individual projets, suh as dams, highways, airports or fatories, on the basis of Diretive 85/337/EEC (known as 'Environmental Impat Assessment' EIA Diretive) and b) plans or programmes on the basis of Diretive 2001/42/EC (known as 'Strategi Environmental Assessment' SEA Diretive) in order to first assess impats and then propose speifi ations to ontrol them. The goal of both Diretives is to ensure that plans, programmes and projets with signifiant impats on natural and human environment are designed subjet to an environmental assessment, prior to their approval and implementation. Due to eonomi growth and population inrease the last few deades, solid wastes volume has inreased and environmental impats from their unontrolled disposal were more intense. Illegal dumpsites are soures of air, soil and water pollution and therefore they should stop operating or should be replaed immediately by sanitary landfills (Thobanoglous and O Leary, 2002). The main environmental problems aused by unontrolled dumpsites are mainly due to lak of a) water proof systems at the bottom and the slopes of a landfill, b) leahate drainage system, ) biogas management system, d) flood ontrol, e) fire protetion system, f) site fening, g) visual sreening and landsape improvement works and h) environmental monitoring (Lolos et al., 2007). Colletion and management of leahate produed in a landfill is a key fator to obtain protetion and remediation of the aquifer. Therefore, the development and appliation of methodologies for preise traking of possible ontamination soure and leakage due to onstrution failures are very important. 1.1 Previous Experiene Although speifi proedures that take plae during ontaminant mass transport in the ground, have already been desribed with good auray in lab sale (Nelson et al. 2003; Wei, 2006; Sharma and Dixit, 2013; Chang and Clement, 2013) however there is an ambiguity of the way that a ontaminant is diffused and dispersed in an aquifer underneath a landfill. This is mainly due to the unertainty related to the determination of neessary aquifer parameters to desribe the omplex physial, hemial and biologial proesses that take plae in a landfill (El-Fadel et al., 1997). In 1999, Mato (1999) presented the key features of a EIA proedure involving the establishment of sanitary landfills in five muniipalities in Tanzania. The risk of potential soil and groundwater ontamination was onsidered extremely high sine the sites were omposed of high permeability sand soil allowing pollutants to travel great distanes in the aquifer. Several ases determining groundwater leahate pollution using analytial, geophysial and hemial methods were reported in the literature (MaFarlane et al. 1983; Reinhard et al. 1984; Albaiges et al. 1986; Pastor and Hernández, 2012). There are limited referenes to experimental or mathematial modeling setups that were used to determine groundwater ontamination due to unontrolled solid wastes disposal. An experimental setup was built by Vourdias (2001) to assess the effets of ontaminant desorption on the effetiveness of pump - and - treat remediation system in a shallow homogeneous aquifer ontaminated by hazardous waste materials illegally disposed in dumpsites. Verwiel et al. (2001) have also developed a groundwater flow model of Gray Wolf aquifer in Central Arizona U.S., to study the most effetive way of groundwater drainage in this speifi area where a sanitary landfill was operating and more spae was needed to dispose urban solid wastes. Additionally Abu-Rukah and Al-Kofahi (2001), after monitoring several physial and hemial parameters in a landfill in El-Akader in Northen Jordan, onluded that the quality of groundwater had been signifiantly deteriorated due to leahate ontamination and as impat, water resoures in the region ould not be used any more. Aording to Fatta et al. (2002), the unontrolled infiltration of leahate into vadose zone and then into saturated zone was onsidered to be the most serious environmental impat in Ano Liosia Landfill in Greee. In their analysis a groundwater flow and ontaminant mass transport model of the region in ombination with Eosim system have been developed, to propose an integrated environmental monitoring and modeling system. Papadopoulou et al. (2007) developed a mathematial model in order to evaluate the degradation risk of groundwater quality in areas with important soial and eonomi interest, in ase of landfill leahate ontamination. Their results showed that, in ase of a toxi groundwater ontamination, the ontaminant plume, due to the hydrogeologial onditions in the

3 ENVIRONMENTAL IMPACT ASSESSMENT OF A METRO INFRASTRUCTURE FACILITY CONSTRUCTION 3 region suh as high hydrauli gradient and permeability, ould affet the quality of extrated groundwater. Rouholahnejad and Sadrnejad (2009) estimated leahate quantities that might infiltrate into the aquifer where a landfill in Lebanon was loated based on Hydrologial Evaluation of Landfill Performane (HELP) model. The sensitivity analysis showed that hanges in the origin of ontamination, hydrauli permeability and ontaminant dispersion ould signifiantly affet ontaminant mass transport. A numerial solution of finite differene ontaminant transport equation was also arried by Jhamnani and Singh (2009) to model Bhalaswa aquifer in New Delhi, India where an unontrolled landfill was operating, without any aquifer protetion measurements. The results were in agreement with the observed hloride onentrations in groundwater highlighting serious ontamination problems. The inability of Indian administration to aount for environmental damages in groundwater resoures in the state of Tamil Nadu India was investigated by Venkatahalam (2004). Finally, the evaluation of surfae and subsurfae water quality in Lagos, Nigeria, proved that unontrolled wastes disposal in water hannels in ombination with buried wastes ontribute to heavy metal groundwater ontamination by violating EPA limits either in maximum values or in time levels (Odukoya and Abimbola, 2010). 2. MATHEMATICAL MODELING ESTIMATION OF CONTAMINANT PLUME Mathematial modeling is used to desribe and analyze mehanisms that ontrol groundwater flow and mass transport in order to first determine ontaminant plume extent due to leahate prodution and then propose neessary ations to resolve possible ontamination issues. In this analysis groundwater modeling is used to first ahieve a good understanding of the physial proesses that take plae in Eleonas aquifer and then estimate the response of the aquifer after the onstrution and during the operation of the proposed METRO failities. The area of interest is loated in the North Northwest setion of Eleonas region in Attikis Prefeture (Greee), east of National highway of Athens Lamia (Kifissos river), west of Profiti Daniel stream, south of Iera Odos street and north of Orfeos street (Figure 1a). The simulated area was approximately 0.8 km 2 (1000m x 800m). Aording to the available historial data, until 1945 agriultural ativities were taking plae in the area, the following deades there was a dramati hange in land uses onsidering mainly industrial and ommerial ativities. In partiular, a part of this area was used to quarry lay for the adjaent erami industries. After lay was fully exavated at early 80 s, the area then was used as an unontrolled wastes dumpsite where urban solid wastes mixed with manmade fill material were disposed. a) b) Figure 1. a) Area of study - Solid lines indiating the loations of METRO tunnel and depot b) Loation of buried solid wastes within the area of interest - Dash line (ΑΤΤΙΚΟ ΜΕΤRΟ S.A., 2005; 2009) In 2000, the onstrution of the underground tunnel to extent METRO line 3 to Egaleo Town was planned. The projet also inluded the onstrution of Eleonas station and a METRO depot within the

4 4 DIMITRIOU and PAPADOPOULOU area of interest. Geologial investigation indiated the existene of wastes overed by manmade deposits (Figure 1b). The urrent onditions were estimated to be very hazardous sine solid wastes were found within a high ultural value urban area lose to the historial Athens ity enter. In addition the existene of an unontrolled landfill reated serious environmental issues to natural environment as well as to publi health in terms of drinking water and irrigation quality. Based on the olleted ontamination data, ammonia mass transport was hosen to be modeled as it was onsidered the main soluble groundwater ontaminant in the region. Ammonia deprotonates a small fration of the water to produe ammonium whih is an indiator of possible baterial, sewage and animal waste pollution (WHO, 2003). Following hronologially the onstrution ativities that took plae in the area, the developed groundwater model was divided in four stages. In this way, an aurate representation of the hanges in the aquifer was obtained. In the first stage, the initial onditions in the region prior to any onstrution were ahieved for a period of one year ( ). During the seond stage, the onstrution of METRO tunnel from 2002 till 2006 as an impermeable boundary signifiantly hanged groundwater hydrauli field. In the third stage, the onstrution of METRO depot was ompleted within a 3-year period ( ). Finally in the fourth stage, a predition of aquifer response under the new onditions from 2009 until 2012 was onsidered. An additional senario (Zero Senario) was also developed to simulate aquifer behavior if no onstrution ativity was onsidered for a 10-year period during whih the onstrution of the proposed METRO failities ould be ahieved. In-situ geologial investigation inluding a series of sampling boreholes brought into light the existene of a ontaminated soil layer under a waste material layer. Numerous sampling boreholes were neessary to aurately determine geologial formations, the thikness and extent of waste material with a high level of auray despite the great inongruity and anisotropy of the areas geology (ATTIKO METRO S.A. 2005). In this study, Prineton Transport Code (PTC), a 3-D mathemati algorithm was used to determine the physial harateristis of groundwater flow and ontaminant mass transport in the area of interest solving the respetive partial differential equations (Eq.1-3) based on a hybrid algorithm solving a finite elements system in horizontal and a finite differenes system in vertial diretion respetively (Babu et al, 1997; Pinder, 2002). x (K xx H ) (Kyy h y ) z (K zz h z ) S h t r i (x x i ) i 1 (y y i ) (z z i ) 0 (1) K h 0 (2) x [ xx x xy y xz z ] y [ yx x yy y yz z ] z [ zx x (3) zy y zz z ] (w ) ( x x y y z z ) [1 E()] ( t ) 0 where h is the hydrauli head, K xx, K yy, K zz is the hydrauli ondutivity in the diretion x, y and z, S is the storage oeffiient, Q i is the flow of water (pumping or supplying) at the position i, δ() is the funtion delta of Dira, r is the number of soures of pumping or supplying water, is the onentration of a ontaminant at a point (x, y, z) at time t, θ is the porosity of the aquifer, E() is the absorption equation, Q is the pumping apability, w is the onentration of pumping water at point (x i, y i, z i ), V x, V y, V z, are the omponents of veloity vetor and D xx, D yy, D zz are the dispersion oeffiients alulated by the following equations: xx (a x 2 a 2 T y a z 2 ) yy (a 2 T x a y 2 a z 2 ) xx (a x 2 a 2 T y a z 2 ) yx xy (a -a T ) x y = yz zy (a a T ) y z zx xz (a a T ) z y (4)

5 ENVIRONMENTAL IMPACT ASSESSMENT OF A METRO INFRASTRUCTURE FACILITY CONSTRUCTION 5 where D M is the moleular diffusion oeffiient, α L is the longitudinal dispersion, α Τ is the horizontal omponent of the traverse dispersion, α V is the vertial omponent of the traverse dispersion. In Figure 3, a simplified geologial NW-SE ross setion is presented, showing the geologial layer disreatization in the developed simulation model. The waste material was not present in the entire modeled area therefore it was hosen to be desribed not as a layer but as a lens of material with different hydrauli and soil harateristis at a speifi area within layer 3. The depth of the various geologial formations was imported into the model onsidering that PTC algorithm aepts only positive elevation values. For that reason, a zero elevation level was set (0.00m) and absolute elevation values for all layers were properly modified. The different geologial formations present in the modeled area are haraterized as (ATTIKO METRO S.A., 1997): Geologial basement: Impermeable Athenian shist, Layer 1: Low permeability neogene deposits inluding marls and siltstones, Layer 2: High permeability in the upper part of the neogene deposits and in the lower part quaternary deposits (onsisted of sand gravel, layey sand and gravel), Layer 3: Low permeability quaternary deposits (onsisted of sandy gravel and silt), Layer 4: High permeability manmade deposits. Figure 2. Simplified geologial ross setion (no sale) In order to determine flow and mass transport boundary onditions, water level, ontaminant onentration field measurements and pumping data were olleted. No-flow boundary onditions (b) were set in the southern, eastern and western boundaries of model domain whereas in the northern and southeastern part of the domain, a 1 st type flow b was set based on water level values observed in existing piezometers in the modeled area prior to any onstrution works. The existing pumping ativity inside the modeled area was set as 2 nd type flow b. Also, the ontaminant plume evolution was approximated onsidering buried solid wastes as a onstant soure of ammonium. Table 1. Hydrauli parameters for eah layer of the model Hydrauli Condutivity K (m day -1 ) Storage Coeffiient S Porosity n Dispersivity layer layer layer layer

6 Depth Field 6 DIMITRIOU and PAPADOPOULOU The physial system was estimated to reah steady state onditions very fast so initial onditions were assumed onstant over the entire domain. Model parameters were obtained from in-situ field measurements and water sample hemial analyses and they were deterministially set (Table 1). Additionally the simulated aquifer was onsidered as onfined and preipitation rate was set equal to 400mm yr Simulation stages a) 1 st Stage The alibration of the developed groundwater simulation model was obtained based on onditions observed prior to any onstrution ativity (ATTIKO METRO S.A., 1997) Field vs Simulated R² 0, Simulated (a) 30 1st stage Calibration Points Field measurements Depth (m) Simulated values Depth (m) Figure 3. Field water level measurements vs. simulated water level values (b)

7 ENVIRONMENTAL IMPACT ASSESSMENT OF A METRO INFRASTRUCTURE FACILITY CONSTRUCTION 7 Calibration results (Figure 3a) showed a good orrelation between field water level measurements and simulated water level values (R 2 = 0.8), mainly in the high interest entral part of the modeled area (e.g. points 5, 6, 11, 13, 18, 26, 27, 28 and 29) while there were some deviations in the Northern and Southern sides of the model domain (e.g. points 9, 10, 15, 17, 25 and 30) due to the imposed boundary onditions (Figure 4). As Konikow and Bredehoeft (1992) pointed out in their analysis: The model is onsidered alibrated when it reprodues historial data within some subjetively aeptable level of oherene based on one s judgment. Simulated and observed data urves follow a similar trend (Figure 3b). Unfortunately, the lak of piezometri data in the extended region surrounding the modeled area was ruial in order to aurately desribe the aquifer behavior at the boundaries. The unertainty assoiated with the imposed boundary onditions affets in some degree the differentiation between simulated and observed water level measurements at the boundaries. N Green olor: good orrelation Red olor: moderate to bad orrelation b) 2 nd Stage Figure 4. Piezometri map Calibration results (after ATTIKO METRO, 1997) During the 2 nd stage, the onstrution of METRO tunnel from 2003 until 2006 was implemented. The tunnel was represented as impermeable segments plaed in layers 2 and 3 along the Northern boundary (zero flow ondition Neumann b). The rest of the model setup remained as in Stage 1 for a 3-year simulation period. ) 3 rd Stage In the 3 rd Stage, groundwater flow and ammonium mass transport were simulated after the onstrution of METRO depot and the removal of solid wastes ( ). It should be notied that buried wastes were only removed from the area where the depot was onstruted therefore small but signifiant quantities of wastes remained buried elsewhere. The depot impermeable walls were imported into the model (layers 2 and 3) as zero permeability soil lenses. d) 4 th Stage Up to date model predition Groundwater flow and ammonium mass transport onditions were simulated for an additional 3-year period in order to update aquifer s behavior up to e) Zero Senario No onstrution Zero senario was developed to simulate aquifer s behavior in ase that METRO failities were not implemented in the region. In this senario, the evolution of ammonium plume in the region for a 10- year period due to produed waste leahate was estimated. A omparison of ammonium plume evolution with (4 th stage) and without (Zero Senario) METRO failities proved that aquifer soil and groundwater onditions were signifiantly improved by METRO projet implementation due to the

8 8 DIMITRIOU and PAPADOPOULOU removal of large volumes of wastes from the soil and the ontainment of subsurfae water pollution that was ahieved. 3. Results analysis estimation of ontaminant plume evolution During the 1 st Stage, groundwater flow had a general Northwest to Southeast diretion. The main drainage axis ran in the entral part of the model from N-NW to S-SE diretion and the seondary along Profiti Daniel stream (Figure 5). N Watershed ---- Drainage axis Figure 5. Groundwater flow (Layer 2) Figure 6. Conentration of ammonium in the 3-D model (Stage 1) blue line indiates ammonium onentration >10mg l -1 The mapping of ammonium plume was based on the maximum allowed value for disposal in natural reservoirs (10 mg l -1 ) aording to Greek legislation. The simulation results of ammonium ontaminant

9 ENVIRONMENTAL IMPACT ASSESSMENT OF A METRO INFRASTRUCTURE FACILITY CONSTRUCTION 9 transport in layer 3 (where solid wastes were found) showed that ontamination has moved few hundred meters from the main soure of pollution following the main groundwater flow diretion. The highest value of ammonium onentration in layer 4 was observed south of the main soures of ontamination and ammonium plume had the same diretion as in layer 3. In the deepest layers 1 and 2, smaller values of ammonium were simulated (~25 mg l -1 in layer 2 and almost zero in layer 1) indiating limited ontaminant leahate from layer 3 downwards due to the existene of low permeability geologial formations in these two layers. In layer 2, ammonium onentrations were alulated south of main ontamination soure, following the main groundwater flow diretion (Figure 6). During the 2 nd stage, METRO tunnel has been onstruted along the Northern part of the modeled area and an impermeable boundary (zero flow b) at layers 1, 2 and 3 was imposed. As result, a signifiant hange in hydrauli field (piezometri lines) in the North part of the onstrution site has been observed. Espeially in layer 2, where the main part of impermeable struture was imposed, signifiant groundwater flow redution has been observed due to the existene of underground tunnel that works as a barrier (Figure 7). By slowing down groundwater flow, a limited development of ammonium plume in layer 3 was observed as well as in layer 4 where buried wastes were loated (Figure 8). Figure 7. Piezometri field during the 1 st and the 2 nd simulation stages (Layer 2) During the 3rd simulation stage, the impermeable walls of METRO depot were inserted into the model. In order for the depot to be onstruted, buried wastes should be prior removed so the soures of ontamination within onstrution zone have been removed whereas outside the depot s perimeter solid wastes still remain buried. The ammonium plume development in this stage was slow with a limited spread of ontamination. The maximum value of ammonium (300mg l -1 ) was alulated in layer 3 at loations south of depot walls while dispersion was quite low. The low observed onentration values as well as the small plume extent were due to the onstrution of depot walls that were working as a barrier to groundwater flow south of the depot. It should be mentioned that small but signifiant quantities of wastes remained in the area but due to the underground tunnel onstrution; groundwater flow was signifiantly redued resulting to limited ammonium plume spread. In the final 4 th stage of simulation, the behavior of the physial system after the ompletion of METRO infrastruture projet was simulated. During this 3-year period, groundwater flow was onstant and ammonium ontamination problem was mostly solved even though small quantities of wastes in layer 3 have not been removed ausing a limited ontamination (Figure 9).

10 10 DIMITRIOU and PAPADOPOULOU Figure 8. Conentrations of ammonium at the 4-layer model (2 nd stage) Figure 9. Ammonium plume spread during the 4 stages of simulation model (Layer 3)

11 ENVIRONMENTAL IMPACT ASSESSMENT OF A METRO INFRASTRUCTURE FACILITY CONSTRUCTION Disussion Most of the times, the ost of preventive measures is 10 to 20 times lower than the neessary funds to lean up a polluted aquifer (Rasula and Rasula, 2001). Therefore the development of a monitoring system that will regularly reord the quality of territorial and water resoures in a large sale infrastruture projet suh as a highway, a sanitary landfill and an industrial zone is mandatory in order to meet the imposed environmental requirements. Rasula and Rasula (2001) proposed a hydrogeologial approah for the establishment of an ative groundwater quality monitoring system in linear zones of infrastruture failities. Calo and Parise (2009) highlighted the need for a monitoring groundwater system in karstified areas that are partiular vulnerable to groundwater pollution. The risk of pollution is extremely high in areas like the one in Mostar, Bosnia-Herzegovina, where for many priorand post- war years hundreds of tons of solid and toxi wastes have been disharged in abandoned mining areas operating as unontrolled dumpsites. As far as monitoring groundwater quality in an infrastruture faility, Pandey et al. (2011) went a step forward by proposing a groundwater sustainability infrastruture index (GSII) as a measure of groundwater sustainability. The GSII is omposed by five omponents related to groundwater monitoring, knowledge generation and dissemination, regulatory interventions, publi partiipation and institutional responsibility. Even though the omponents of GSII are quite universal, their study have shown that in order to obtain omparable results between different ases a sensitivity analysis of GSII is mandatory The onstrution works that took plae from 2002 till 2009 in the greater Eleonas region in Attikis Greee showed that the removal of solid wastes in ombination with remedial ations suh as soil replaement signifiantly improved the environmental onditions in this aquifer. In the ase of no METRO projet implementation (Zero senario) the plume extent would have been muh larger (Figure 10). It should be notied that after the end of the onstrution during the 4 th stage of simulation, small quantities of wastes south of METRO depot remained buried into the aquifer justifying the existene of low onentration ammonium values there. In onlusion the ontainment of the ammonium plume was obtained after remedial ations taking to protet the territorial resoures of the region during the infrastruture projet. Otherwise, if the onstrution of METRO depot has being postponed ammonium plume would had been extended outside the property boundaries reating serious environmental problems in the greater region. Figure 10. The simulated ammonium plume extent with (4 th Stage) and without (Zero senario) the implementation of the METRO infrastruture faility (Layer 3) 5. Evaluation of methodologial approah - Suggestions The simulation results were in a good agreement with the results of the environmental investigation obtained by ATTIKO METRO S.A. even though the boundaries of ATTIKO METRO S.A. property where the environmental investigation took plae do not oinide with the boundaries of the modeled area.

12 12 DIMITRIOU and PAPADOPOULOU By using PTC mathematial algorithm, the area of interest was well enough simulated as far as groundwater flow and ammonium mass transport fields. Nevertheless, in order to reate a realisti model, ertain assumptions were made. The hanges in groundwater flow and ontaminant mass transport proesses were gradually obtained sine the transition of the physial system from one implementation stage to another was not instantaneous; there was always a time period of onstrution works between the various onstrution phases that ould not be easily represented during the simulation proess. Additionally, there was limited quantitative and qualitative groundwater data for the period after wastes removal. Some suggestions oming out from this analysis as far the protetion of the environment in the greater area of interest are: a) the design of an environmental monitoring program in order to analyze soil and water quality data in a regular basis and b) the implementation of a groundwater quality monitoring system, espeially in the region south of METRO depot that ould deisively ontribute in an aurate model verifiation and an environmental impat assessment of the onstrution ativities. Finally, among the priorities of ATTIKO METRO S.A. is the onstrution of a water runoff network whih will dramatially ontribute to the improvement of water quality in the surrounding area (ATTIKO METRO S.A., 2009). 6. Conlusions In onlusion, the findings of this analysis proved that the implementation of a large transport infrastruture projet like the onstrution of METRO failities (tunnel, station and depot) in Eleona Attikis Greee ould at environmentally benefiial for the region. On the oasion of the onstrution of METRO depot, a large sale ontamination problem of soil and water resoures in the region was revealed. The existene of buried wastes poses serious risks to the quality of soil and subsurfae water resoures in the region resulting in signifiant impat on publi health. The projet implementation imposed removal of signifiant amounts of buried solid wastes reduing environmental burden in the aquifer. In the authors knowledge there is no doumented ase in the literature of suh a large transportation infrastruture projet whih may have signifiant effets on the improvement of soil and water resoures in an urban area. Aknowledgements: The authors would like to thank the ATTIKO METRO S.A. for providing them the neessary data for the implementation of this study Referenes Abu-Rukah Y. and Al-Kofahi O. (2001), The assessment of the effet of landfill leahate on ground-water quality a ase study. El-Akader landfille site- north Jordan, Journal of Arid Environments, 49, Albaiges J., Casado F. and Ventura F. (1986), Organi indiators of groundwater pollution by a sanitary landfill, Water Researh, 20, ΑΤΤΙΚΟ ΜΕΤRΟ S.A., Geologial and Hydrogeologial Study, - Extension Projet Phase 1, Western Extension of line 3 Keramikos Egaleo, Edafomihaniki EPE (in Greek) ΑΤΤΙΚΟ ΜΕΤRΟ S.A, Final Report of Presentation of Environmental Investigation, Edafomihaniki EPE (in Greek) ΑΤΤΙΚΟ ΜΕΤRΟ S.A, Engineering Geology Study and Hydrogeologial Study, Edafomihaniki EPE (in Greek) Babu D.K., Pinder G.F., Niemi A., Ahlfeld D.P. and Stothoff S.A., Chemial Transport by Three-Dimensional Groundwater Flows, Prineton University, 84-WR-3, USA.

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