Description
From the Catasto Sorgenti (Register of Sources), the springs tapped for public drinking water were initially selected. This resulted in approximately 1600 springs. After agreeing the necessary cooperation with the respective municipalities or aqueduct management bodies, samples were taken and analyses performed.
In addition to the usual chemical-physical parameters, the analyses included numerous trace elements, including numerous metals. The importance of these elements derives both from their possible toxicity and their importance in defining the underground supply circuit of the spring.
In order to identify anomalies in the concentrations of the parameters analysed, reference was made to the threshold concentration values for the good chemical status of groundwater bodies, introduced by Legislative Decree No 30 of 16/03/2009.
The data collected
621 samples were taken from 611 sources. The subsequent analyses, carried out on purpose, represented the most important part of the volume of data examined, both in terms of quantity and homogeneity. To these were added 79 analyses (on 10 sources) carried out for the Hydrogeological Monitoring of the Brenta Group (MIB Project), 67 analyses carried out in 2007 for the Brenner Railway Special Project, and 99 analyses of uncaptured sources sampled in 2005 by the Tridentine Museum of Natural Sciences as part of the Crenodat Project. A further 236 analyses were extracted from the Catasto Sorgenti. In the case of sources with multiple analyses, the most recent and complete ones were used.
Spatial Dissemination
The development of the RIASPAT project, which necessarily required the collaboration of the competent municipalities, could not be extended to the entire territory of the Province of Trento.
I comuni coinvolti nel progetto
In the attached image, the municipalities that responded positively and are therefore included in the study are indicated in hatches. Note that the municipalities referred to are those present in 2006. Some of them have since merged. The borders of the municipalities that later merged into larger municipalities are shown in black.
Description of the reports
The reports are generally organised by municipality. Occasionally, municipalities that are not too large and have sources with homogenous characteristics have been merged into one report. Sometimes, springs located outside the municipality have also been included in a report of a municipality, if they are used for drinking purposes by that municipality.
In order to be able to better find the report for each municipality, a special municipality-report table was prepared.
In each report, the data peculiar to each source are given in a very concise manner. The analytical results of the sampled waters are given at the bottom of each report.
For each source, the official name (if any) and the unique code is given.
In order to illustrate both the position of each spring examined and the geological context in which it is located, two maps have generally been included in the report: the first illustrates the position of each spring in relation to the surveys, towns and municipal boundaries, while the second shows a simplified lithological framework with the major structural features. The first map also shows the hydrogeological buffer areas defined by the PAT Water Resources Map. These areas have been identified for all the springs captured for public drinking use, and the constraints indicated by the PUP apply in them. This is the map legend .
For each source described, an average flow rate value is indicated: this is an indicative value, often based on a few measurements, but nevertheless useful for estimating at least an order of magnitude of the resource. In the presence of numerous flow measurements, an attempt has been made to give an indication of the stability or variability of the flow.
Potential vulnerability factors, which emerged both during the surveys and from reading the analyses, were sometimes highlighted.
The ratios between the concentrations of the main cations and anions are generally shown in the Piper diagram, which represents the chemism of each water analysed with a point in each of the three parts of the diagram. The different areas of the diagram thus identify 'families' of waters with similar chemical characteristics, generally well correlated with the lithologies of the feeding basins.
The concentrations determined by the analyses were finally compared with the threshold values listed in the table below to assess whether they belonged to the good chemical quality status.
| Chemical species | threshold value | unit of measurement | |
| Aluminium | Al | 200 | µg/l |
| Arsenic | As | 10 | µg/l |
| Cadmium | Cd | 5 | µg/l |
| Chromium | Cr | 50 | µg/l |
| Copper | Cu | 1000 | µg/l |
| Iron | Fe | 200 | µg/l |
| Mercury | Hg | 1 | µg/l |
| Nickel | Ni | 20 | µg/l |
| Lead | Pb | 10 | µg/l |
| Antimony | Sb | 5 | µg/l |
| Selenium | Se | 10 | µg/l |
| Vanadium | V | 50 | µg/l |
| Zinc | Zn | 3000 | µg/l |
| Boron | B | 1000 | µg/l |
| Fluorides | F | 1.5 | mg/l |
| Chlorides | Cl | 250 | mg/l |
| Ammonia nitrogen | NH4 | 0.5 | mg/l |
| Nitrites | NO2 | 0.5 | mg/l |
| Nitrates | NO3 | 50 | mg/l |
| Sulphates | SO4 | 250 | mg/l |
Threshold values for the 'good chemical status' of groundwater bodies, according to Legislative Decree No 30 of 16/03/2009.
Validity limits of the analyses
The analyses taken into consideration were performed using modern analytical methods and have a good level of precision. It should be noted that the samples were taken over a period of three years, at different stages of the hydrogeological cycle. We thus find ourselves comparing analyses carried out in different seasons, and this calls for caution: in fact, during the groundwater recharge seasons, the supply of fresh water from the surface often results in the release of less mineralised water due to the reduced contact time with the rock.
It should also be remembered that methods for quantitative analysis have evolved over time and may differ from one laboratory to another. Analytical values may therefore have different accuracies, and different detection limits.
Cases of values considered to be abnormal are also highlighted. In the absence of counter-analyses or time series, it was not possible to attribute a certain meaning to these values. In some cases, certain parameters, especially among the trace elements, were likely to be overestimated, and this emerged due to their inconsistency with the geological context and their relationships with other associated chemical species.
People involved in the project
This project arose from the idea of critically interpreting the data collected in the Sources Cadastre.
An initial study was carried out by Claudia Tomazzolli in 1999, with a degree thesis at the University of Trento entitled: Le sorgenti nel Trentino Tomazzolli C. (1999) - supervisor G. Stoppa.
Roberto Laveder completed his doctoral thesis at the Ca' Foscari University of Venice in 2006 with the title: Hydrogeochemical characterisation of ground waters in the Province of Trento (Alps, Northern Italy) - supervisor G.M. Zuppi. The same Dr. Laveder then developed the RIASPAT project, under the coordination of Dr. Mauro Zambotto, with a collaboration contract at the Geological Service of the P.A.T.. An initial revision of the work was carried out by Dr Mariangela Balboni of the P.A.T. Geological Service. The final drafting of the reports was taken care of by Dr Gianluca Tommasi of the Geological Service P.A.T..