Geochemical evolution of the Thriassion Plain groundwaters, Attica, Greece
- PDF / 5,632,437 Bytes
- 21 Pages / 547.087 x 737.008 pts Page_size
- 48 Downloads / 188 Views
Geochemical evolution of the Thriassion Plain groundwaters, Attica, Greece D. Hermides
&
D. Kyriazis & P. Makri & A. Ermidou
Received: 18 March 2019 / Accepted: 13 July 2020 # Springer Nature Switzerland AG 2020
Abstract 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 D. Hermides (*) : D. Kyriazis : A. Ermidou Agricultural University of Athens, Athens, Greece e-mail: [email protected]
D. Kyriazis e-mail: [email protected] A. Ermidou e-mail: [email protected] P. Makri (*) University of Athens, Athens, Greece e-mail: [email protected]
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. Keywords Groundwater . Seawater intrusion . Contamination . Hydrogeochemistry . Thriassion Plain
Introduction Geochemical processes occurring within groundwater and chemical reactions with rock minerals decisively influence water quality (Appelo and Postma 1993, Freeze and Cherry 1979). The chemical composition of groundwater is mainly influenced by anthropogenic factors creating serious environmental problems (Lloyd and Heathcote 1985). In addition, the composition of groundwater is a function of a large number of factors, for example, the partial pressures of the gas phase, the pH and the oxidation potential of the water (Fetter 2001). Groundwater composition in coastal aquifers is affected by seawater intrusion, due mainly to overpumping conditions or other sources caused by either geological factors or human activities. These sources include entrapped fossil seawater, evaporites dissolution, leakages through overlying aquifers, thermal inflows and sewage pollution (Li et al. 2016, Alam 2010, Alcala and Custodio 2008, Post 2004, Andreasen and Fleck 1997, Heathcote and Lloyd 1984). Knowledge of geochemical processes that control groundwater
561
Page 2 of 21
composition is required for integrated water resources management (Hem 1985). Thriassion Plain is a coastal area located close to Athens. It i
Data Loading...
