Impatto delle attività agronomiche sulle aree di salvaguardia delle prese da falda

The interaction between agronomic practices and the use of groundwater for drinking water, poses a problem of coexistence between fundamental productive activities for most of the Italian and European territory. The relevance of the problem is evident, just to define methods and rules for the correct management of the underground resource, expressly provided for by the law (e.g. in Italy. D.Lgs n.152 of 3 April 2006), being the task of the Regions the identification of wellhead protection areas. Within the latter several activities are restricted, including agricultural activities carried out with the accumulation and use of chemical and natural fertilizers or pesticides. What is the decay of these substances in the first layers of the soil and their ability to alter the quality of the groundwater and / or to reach an intake work for drinking water is substantially unknown, and the alarms on the presumed danger for human health enhance the need to develop of a specific research. To this aim a diffuse activity has been developed on two typical areas of the Veneto piedemont territory interested by Prosecco vineyard, Valdobbiadene (TV) and Conegliano (TV). In these areas relevant well intakes guarantee the drinking water supply to large areas of the territory. Inside each of the two sites, the infiltration and the mobility of a tracer (KBr) and a Glyphosate based herbicide commonly involved in the vineyards protection, were locally monitored and verified in two areal parcels (25 m\textsuperscript{2} each) subjected only to meteorological forcing. The study considered the infiltration process up to a depth of 70 cm, dependent on the pedologic properties of the shallower soil layers, the plant coverage and the root apparati, to obtain the calibration of a one-dimensional hydraulic model for each one of the four monitored parcels. This being the infiltration recognized as the driving mechanism of the pesticides movement. The modelling of the pesticide mobility, monitored together with and its principal metabolite on a temporal window of six months, resulted more complex suggesting a greater affinity of the observed chemical species to be adsorbed to the soil matrix rather than be dissolved in water and transported toward the deeper layers of the soil. The different results observed between parcels of the same site, suggested a dependency of the pesticide vertical mobility on the heterogeneity of soil properties. To extend the experimental evidence to the scale of the wellhead protection area, a large series of tests has been developed in each site using a double ring infiltrometer and a 30 cm deep soil sampler to evaluate the spatial variability of the infiltration capacity, the soil organic content (TOC) and the soluble phosphorous concentration ($PO_4{3-}$ ), seeming the latter apparently correlated to the GLP adsorption. By this way we try to move from a point-wise to a field scale, where the soil properties are described by pedologic maps developed by regional authorities that can be combined with the amount of plant protection products distributed on the Treviso province, to define a vulnerability map of the investigated area. The research results are at the end organized in three subjects linked together: i) modeling of the in-situ experimental evidences of the injection subjected to natural meteorological forcing; ii) characterization of soil heterogeneity based on water infiltration analysis and basic chemical properties of the soil; iii) impact of the total amount of PPPs used in the province of Treviso in the wellhead protection area risk assessment.