GEOCHEMICAL STUDY OF THE URBAN AND SUBURBAN AREA OF NAFPLION CITY, ARGOLIDHA PREFECTURE, HELLAS

Résumé

Soil, as the primary receptor of anthropogenic urban contamination acts as a sink for a variety of toxic and other hazardous substances. It constitutes, therefore, an indicator of contamination and may be utilised geochemically to assess environmental quality of urban and suburban areas. In Nafplion, an urban and suburban area of 50 km2 , was investigated using for the first time in Hellas an integrated approach with all available geoscientific techniques to make an in-depth environmental impact assessment. One of these techniques was applied geochemistry, which mapped the geochemistry of surface soil (0-10 cm) with 144 samples, collected on a regular grid of 500 x 500 km. The following fifty determinands were measured on the soil samples: Ag, Al, As, B, Ba, Be, Bi, Ca, Cd, Ce, Co, Cr, Cu, Fe, Ga, Ge, Hg, K, La, Li, Mg, Mn, Mo, Na, Nb, Ni, P, Pb, Rb, Re, S, Sb, Sc, Se, Sn, Sr, Ta, Te, Th, Ti, Tl, U, V, W, Y, Zn, Zr, pH, electrical conductivity and grain-size distribution. The aim of the geochemical study was to distinguish, as far as possible, the origin of chemical elements, and (i) to classify them as geogenic or anthropogenic; (ii) to delineate contaminated areas, and (iii) to assess potential future impacts of human activities on soil. Interpretation of the resulting geochemical patterns has shown that those of Al, Fe, Be, Ce, Cr, Co, Ga, Ge, K, La, Li, Mg, Nb, Ni, Rb, Sc, Sr, Tl, V, Y, W and Zr are of geogenic origin, since they are directly related to parent rocks, whereas patterns of As, B, Ba, Bi, Ca, Cd, Cu, Mn, Mo, Na, P, Pb, S, Sb, Sn, Th, U and Zn are interpreted as being of dual origin, geogenic and anthropogenic. In this paper, the geochemical distribution of only five elements shall be described, i.e., Pb, Zn, Cu, Ni and Na. This case study was indeed very interesting, since for the interpretation of some patterns, even the military history of the area had to be unravelled.