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Sixteen profiles have been characterized from a pedologic point of view: nine in a coastal pinewood, five in agricultural sites and two in a city park. The profiles have been described, sampled and analysed to the purpose of giving a first outline of the pedological complexity of area. Inside the pinewood, soils are affected by the topographical position and the closeness of the surface aquifer. Ustipsamments/ Arenosols occur where the groundwater depth is more than one meter, while at lower groundwater depth Psammaquents/Gleysols are present. Agricultural soils are directly affected by geological characteristics and human land reclamation, and fall within the Haplustepts/Cambisols great groups, with a few distinctions due to the different utilisation of the soil and to the depositional origin. Also the two soils of the city park fall in the Haplustepts/Cambisols great group; however, in this case, the anthropic interference, suggested by the plenty brick fragments detected in the profiles, is quite evident. .

Potentially toxic elements (PTEs) abundances in top soil and along the soil profiles from areas affected by different anthropogenic inputs were investigated. The study area is located within the Ravenna Municipality, a complex territorial system highly affected by industrial (a large petrolchemical complex) agricultural activi-ties. Three zones with distinct environmental features were identified: the San Vitale Pinewood affected by atmospheric deposition pollutans from the industrial complex (PW1, PW4, PW6 and PW8 soil profiles); a public garden within the Ra-venna city center, mainly affected by traffic pollution (GP1 soil profile); the "Luigi Perdisa" farm located immediately northwards Ravenna was selected due to the use of fertilizers as well as atmospheric deposition (PER2 soil profile). The total con-centration of PTEs (Ba, Cr, Cu, Cr, Ni, Pb, Zn) was determined by X ray fluores-cence spectrometry (XRF), and the pseudo-total concentration with aqua regia di-gestion (AR) and ICP-OES quantification in order to evaluate the extractability of the elements. Results showed a significant increase of some PTEs (Cu, Pb, Zn) in the top soil compared to the endopedon. In the Ravenna urban park (GP1 station), Pb and Zn concentrations exceeded the threshold values established by current Ital-ian laws for soils from "public, residential and private areas" (D. Lgs 152/2006). The correlation between top soil and the subsoil highlighted that some PTEs, such as Cu, Pb and Zn, are anthropogenic and they are mainly associated to the deposi-tion of airborne pollutants, whereas other elements (Cr and Ni) are lithogenic.

The hazard assessment of some potentially toxic chemicals assumes significance in view of Italian and Community legislation concerning the protection of human health, water and land pollution (use of compost in agriculture, spreading of sludge and water, relapse fine particles, etc.). This chapter explained the environmental role of several potentially toxic elements. In this regard, the knowledge of the speciation of elements in the environment is important to identify not only the absolute concentrations (mg / kg soil) but also the relationship of the element accumulation in plant tissues and the hazard in the food chain

This paper is focused on the multicomponent exchange processes and elemental cycling in the subsurface and superficial environments which constitute the area of the Pineta di San Vitale and nearby farmlands. The coastal aquifers in the area of the Pineta underwent severe seawater intrusion due to subsidence and over-pumping, yielding a decline in the water quality and driving a number of processes in aquifers and soils. These include cation-exchange reactions by clay minerals, even if the cation exchange capacity of the aquifer is probably low; iron oxy-hydroxides extensive precipitation due to oxic seawater recirculation; adsorption processes of both essential micronutrient and potentially toxic elements on the sur-face of Fe and Al hydroxides. The development of local anoxic conditions due to respiration and decomposition of organic matter allows the reductive dissolution of the iron oxy-hydroxides, which liberate the sorbed elements to porewaters. This re-dox cycling appears to be important in the bioavailability and geochemical cycling of a number of trace metals in the subterranean environment of the Pineta. CO2 charged waters in soils account for the high alkalinity observed in most water sam-ples, through the role of carbonates and the control of pH and the Ca2+ content. The active processes in the surface ecosystem of the plain bordering the Pineta di San Vitale, exploited for agricultural uses, include dry and wet atmospheric deposi-tion from marine and anthropogenic sources, leaching processes during runoff and retention and transport of trace elements by Fe and Mn oxides colloidal particles, through the network of canals and ditches towards the coastland. These processes are sensitive to flow fluctuations, and are deeply influenced by the management of water resources during summer, when a high water supply in irrigated crops is re-quired. Using geochemical simulation codes it is highlighted that the reverse phe-nomenon to salinization, leading to groundwater freshening, is a long process, also depending on the low cation exchange capacity of the site. Even if a detailed study concerning the recharge rate of the aquifers would be necessary, these preliminary observation indicate that attenuation planning for salinization is urgent.

Résumé Il n'y a pas longtemps, le développement socio-économique des lieux était conditionné uniquement par la disponibilité (ou non) d'eau. Pendant ces dernières années, le problème de la pollution des eaux, causé par les quantités considérables de produits toxiques reversés dans les cours d'eaux, a presque dépassé par son importance le problème de la quantité d'eau. Intervenir pour résoudre ce problème est désormais une obligation pour la majorité des pays à haute densité de population et à fort développement industriel. La résolution du problème impose qu’à côté des technologies et des études qui visent à l'assainissement des cours d'eaux dégradés, soient développées des normes et des réglementations législatives pour sauvegarder la ressource d'eau. Ici, on reparcourt l'iter législatif en matière de qualité des eaux qui, commencé en Italie à partir du Décret Legislatif 152/2006, représente aujourd'hui le Texte Unique en matière d'environnement. En s'inspirant du même décret, on fait une comparaison entre les normes à propos de la réutilisation des eaux usées, et les normes proposées par la communauté EU et par l'Environmental Protection Agency (EPA) des Etats Unis, qui en 1992 a publié le « Guidelines for Water Reuse ». Les contenus de cet écrit sont considérés novateurs par rapport aux précédents documents sur le thème, puisqu'ils sont destinés à diffuser le concept de la réutilisation de l’eau en dehors du secteur agricole. Mots-clés: legislation, ressource en eau, eaux usées, épuration, qualité des eaux