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Use of isotopes for groundwater (pollution tracing) Philip Taylor. Aim of this talk …. Isotopes : mature scientific domain … …but ‘underdeveloped’ as far as a policy support tool sporadic use not systematic Showing you some examples. Mission of the JRC.
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Use of isotopes for groundwater (pollution tracing)Philip Taylor
Aim of this talk … • Isotopes : mature scientific domain … • …but ‘underdeveloped’ as far as a policy support tool • sporadic use • not systematic • Showing you some examples
Mission of the JRC … to provide customer-driven scientific and technical support for the conception, development, implementation and monitoring of EU policies … … the JRC functions as a centre of science and technology reference for the EU, independent of private and national interests… “A research based, policy support Institution”
7 Institutes in 5 Member States IRMM – Geel, Belgium - Institute for Reference Materials and Measurements Staff: 280 IE – Petten, The Netherlands - Institute for EnergyStaff: 180 ITU – Karlsruhe, Germany - Institute for Transuranium elements Staff: 250 IPSC - IHCP - IES – Ispra, Italy - Institute for the Protection and the Security of the Citizen - Institute for Health and Consumer Protection - Institute for Environment and Sustainability Staff: 350, 250, 370 IPTS – Seville, Spain - Institute for Prospective Technological StudiesStaff: 100 Total staff: ~ 2300 people Structure of the DG-JRC
Sources of groundwater pollution Isotopic/radionuclideApplications Groundwater Sustainability Groundwater contamination
Why underdeveloped ? • sophisticated equipment used to be required • not compliance issue • Thinking in isotopes is different • Multi disciplinary : geochemistry-modeling-hydrology-isotope science
Sources of groundwater recharge and pollution • Identification pollution source • Groundwater pollutant attenuation • Aquifer recharge from leaking mains • Aquifer recharge from in situ sanitation • Origin/fate N and DOC in groundwater • Origin/genesis landfill leachates • Landfill evolution stability indicators • Vulnerability groundwater source protection areas
Major perturbation of aquifer flow systems • Penetration of Aquifer flow systems • Paleo-freshwater depletion • Aquifer saline intrusion
Urban run-off and sewer flow analysis • Surface water rainfall-runoff analysis • Streambed sediment residence times • Water balance problems in sewerage systems • Origin and interconnection of sewer flows
The power of isotopes • Atoms building blocks of molecules (NaNO3) • isotopes • have different mass (14N, 15N ; 16O, 17O, 18O) • Their relative occurrence changes depending on origin of material (N in manure, sewage, mineral fertilizer, …) • Because they behave differently in nature linked to process/pathways • evaporation/condensation, change in redox state of element, radical reactions … • Radionuclides : 137Cs, 3H
Isotopic information • Qualitative : carries a signature of the origin/process • Also as quantitative tool : how much is this contributing
The ‘isotopic signal’ • ‘delta’ : e.g. 15N, 18O, 34S, 2H …(conventional scale ; how much heavier compared to some reference)
Nitrogen isotope ratio BRGM Orleans : David Widory, et al , J Contam. Hydrology
Additional information brought by multi-isotope approach • Implementation of the method with the addition of d18O(NO3) measurements. • Identification of the pollution sources using N and O isotopes, even in case of the presence of natural denitrification.
multi-tracer approach to tracing nutrient and organic matter sources/sinks in aquatic system • Tracers of NO3 sources and sinks: • 15N, 18O, 17O • Tracers of NH4 sources and sinks: • 15N • Tracers of PO4 sources and sinks: • 18O • Tracers of SO42sources and sinks: • δ34S in SO42- • Tracers of POM and DOM sources and sinks: • 15N, 13C, 34S, etc • Tracers of O producing and consuming reactions: • 18O, 17O of O2 • 13C of CO2 and DIC
Point Recharge using tritium Distance travelled is proportional to recharge from river to groundwater (IAEA, Herczeg)
Example: what is source of groundwater replenishment? Isotopes tell us recharge is by intermittent heavy floods d2H
Soler, Otero et al. Grup de Mineralogia Aplicada i Medi Ambient Dept. Cristal·lografia, Mineralogia i Dipòsits Minerals Facultat de Geologia Universitat de Barcelona
Nitrogen vulnerable zones Pig Manure Osona n i a p S Maresme Chemical Fertilizers Nitrate contamination: 50 mg/l of NO3
Nitrogen vulnerable zones Osona Treatment Plants n i a p S Pig Manure Maresme (a 3% in 2001) Field application as fertiliser or… Fertilization In Osona (1264 km2): ~ 1.000.000 pigs ~ 1.000 pig farms ~ 1.000 pigs/km2 > 10.000 tones of N / year Reverse K K P P N N Osmosis Pumping Infiltration INFILTRATION PUMPING - NO DENITRIFICACION ... dumped in an uncontrolled way in fields
Maresme FERTIIRRIGATION FERTILIZATION VOLATILIZATION REVERSE K K P P N N OSMOSIS NITRIFICATION NITRIFICATION INFILTRATION INFILTRATION PUMPING PUMPING - - NO NO - - NO NO 3 3 - - Cl Cl 3 3 - - Cl Cl DENITRIFICACION DENITRIFICATION Cl- The intensive pumping provokes a recirculation that does not allow denitrification
Maresme: D and O 18 O ( ‰ ) d Seawater 0 -14 -12 -10 -8 -6 -4 -2 0 Rains >20 mm -20 Rains <20 mm Local Meteoric Water Line Groundwater Mai 01 -40 Groundwater Oct 00 D (‰) Weighted Local Rain -7 -6.5 -6 -5.5 -5 -4.5 -60 -25 -30 -80 -35 -40 -100 -45 (δD, δ18O)H2O indicate a rainwater origin, with no marine contribution
Maresme: δ34S Marine sulphate Fertilizers n Maresme n δ34SSO4 suggests that SO42- is linked to fertilisers δ34S (‰) VCDT
June 2006 Wienlaunchof a JRC Institutional NetworkIsotopes for Improved management aquaeous resourcesIFIMAR
IFIMAR • To share scientific and technical knowledge (both theoretical and practical) regarding isotopic measurements for the better management of surface and groundwater resources • To promote the use of this methodology across Europe, via the member states and • To set up possible research projects in this domain, funded from European or national funding • To exchange staff • To train newcomers in this area, so this methodology becomes more common place in the water management domain • To share best practice on how to communicate with water authorities on these issues
N2O formation in terrestrial ecosystems Denitrification NO2- NO N2O N2 NO3- Nitrification N2O Nitrifier-denitrification NH3 NH2OH NO2- NO N2O N2