The GEOBASI (Geochemical Database of Tuscany) open source tools

13 The tools implemented for the new Regional Geochemical Database, called GEOBASI, are hereafter 14 presented. The database has permitted the construction of a repository where the geochemical 15 information (compositional and isotopic) has been stored in a structured way so that it can be available 16 for different groups of users (e.g. institutional, public and private companies). The information 17 contained in the database can in fact be downloaded freely and queried to correlate geochemistry to 18 other non compositional variables. 19 The repository has been aimed at promoting the use of the geochemical data already available from 20 previous investigations through a powerful Web-GIS interface. The resulting graphical-numerical 21 tools in such a complex database have been developed to: 1) analyse the spatial variability of the 22 investigated context, 2) highlight the geographic location of data pertaining to classes of values or 23 single cases, 3) compare the results of different analytical methodologies applied to the determination 24 of the same element and/or chemical species, 4) extract the geochemical data related to specific 25 monitoring plans and/or geographical areas, and finally 5) recover information about data below the 26 detection limit to understand their impact on the behaviour of the investigated variable. 27