Presentation of the research project:Isotopic characterization of aquifers of Milano and Monza/Brianza Provinces

Marco Petitta, Mariachiara Caschetto, Alessandro Lacchini, Valentina MarinelliDipartimento di Scienze della Terra– Università degli Studi di Roma "La Sapienza", Italy

Ramon AravenaDepartment of Earth and Environmental Sciences, University of Waterloo, ON, Canada

Milano, January 15th 2016CAP Holding, WATER SAFETY PLAN

Isotopic study of groundwater used for drinking waters by CAP Holding

- Use natural isotopes in groundwater as tracers, for analyze the origin, the flowpaths, theages of groundwater, but also interactions and processes driving water/rock exchanges,including anthropic contribution of pollutants

- The acquired knowledge can be used for optimizing the water resource management,previewing the future evolution of the aquifer, taking into account changes due to naturalevents (climate changes, surface/groundwater interactions) or to human activities(withdrawals, land use changes, etc.)

- Isotope approach has enormous potentiality, but it is mandatory that collected data areplaced in a correct “hydrogeological” framework, based on a groundwater conceptual modelgenerally known, to be verified and to be detailed thanks to isotope analysis

- Results can be enhanced by a multiisotope approach, including water and other dissolvedcompounds, allowing the comparison of different groundwater flowpath hypotheses,including flow and transport models, and taking into account not only physical and chemicalprocesses, but the biogeochemical ones too

AIM OF THE RESEARCH

Water availability and groundwater exploitation in Europe

90% of drinkable waters in Italy iscoming from groundwater

(but we are using most of the renewable resources)

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Trend- and Trend reversal assessment

European Commission vision (direttive GW e WFD)

Criteria for Chemical Status Assessment

Environmental multisotope approach (CSIA FINGERPRINTING):- Deuterium & Oxigen 18 in water (origin and flowpath of groundwater)- Tritium in water (groundwater age)- N15 e O18 in nitrates: origin, transport and fate of nitrogen in groundwater-S34 e O18 in sulphates: origin and interaction between shallow groundwater anddeep aquifers- C13 e Cl37 in chlorinated solvents, for evaluating origin, transport and fate(degradation, natural attenuation) of pollutants of industrial origin showingminimum concentration in groundwater

Three sampling phases:- November 2015: characterization (about 80 wells for water isotopes, 20 wells fornitrate and sulphate isotopes, 5 for chlorinated solvents) DONE- Spring 2016: second sampling for seasonal changes and individuation of complexsituations- Summer/Fall 2016: third sampling for examination of complex situations

RESEARCH PHASES

THE CONCEPTUAL MODEL AS BASIS FOR RESEARCH

Pic modello

GROUNDWATER MANAGEMENT

AVAILABLE DATA AND REFERENCES

MONITORING NETWORK AND

STRATEGY

CONCEPTUAL MODEL REFINEMENT

COMMUNICATION AND RESULT TRANSFER

RESULT EVALUATIONFIELD

SURVEYS AND MEASUREMENTS

DATA CHECK AND ANALYSIS

POLICY, REGULATORY ACTIONS AND

DECISIONS

FIRST SAMPLINGNETWORK

FIRST SAMPLINGNETWORK

PRELIMINARY RESULTS FOR

WATER ISOTOPES

(FIRST SURVEY)

DISCUSSION AND PERSPECTIVESManagement of groundwater resource, for drinking and for different uses,requires a detailed knowledge of aquifer and hydrodynamics

A conceptual model of groundwater flow is based on hydrogeological,hydrodynamic and chemical information

This “basic” characterization is only a necessary starting point, but frequently itis not sufficient for analizing in detail the processes that affect groundwater,limiting the evaluation of future scenarios

The modern hydrogeology is adopting several different tools, primarly isotopeanalysis (as natural tracers), not only related to the “classical” water isotopes,but also several “new” compounds in water solution

Coupling a solid conceptual model with isotope results on different groundwatercompounds, allows the evaluation of the origines and of the processesinteresting flow and transport; by this way, the future evolution of the“pumped” groundwater system can be previewed and the groundwatermanagement can be significantly improved