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WATER & ENVIRONMENT NEWS

Quarterly No. 8 / 9, December 1999 -

WATER &ENVIRONMENT

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CONTENTS

Isotope techniques in lake waterstudies 3

Lake Titicaca : history and currentstudies 6

The evaporation pan techniquerevisited 9

Groundwater renewal in waterscarce areas 11

Isotope response to dynamicchanges in groundwater systemsdue to long- term exploitation 11

Isotope Hydrology Calendar 11

Geothermal energy resources -Results and achievements ofregional project RAS/8/075 13

Isotopes for improved drinkingwater resources management 13

Workshop on isotope data inter-pretation and integration in site-conceptual models 13

2nd Interlaboratory comparison fordeuterium and oxygen 18 analysisof water samples 14

Challenges and new techniques forlight element stable isotopes 15

Issue No. 8/9, December 1999

Issued by the

Vienna, Austria

International Atomic Energy Agency

A Quarterly Newsletter of the Isotope Hydrology Section

NEWS

ISSN 1020–7120



EDITORIAL

Since its inception in 1997, Water and Environ-ment News has been well received by its read-

ers and has improved the dissemination of currentnews and developments in Isotope Hydrology inour Member States. It also appears to capture adesirable readership, as there is an increased inter-est expressed for participation in upcoming co-ordinated research programmes and other activi-ties.

We recognize that publication of the 3rd issue of1999 of the News has been delayed. This delayresulted from key staff changes in this past year.Although periodic staff rotation is an essential com-ponent of the Agency’s policies, there are occa-sions when some schedules are interrupted. Weintend to minimize these interruptions as much aspossible.

After a nearly 10 years tenure, the last five asSection Head, Dr. Klaus Froehlich retired from theAgency at the end of July. During Klaus’ tenure,the Section‘s contributions to the Agency‘s techni-cal cooperation programme were better reco-gnized and Isotope Hydrology was recognized bythe Member States as a significant priority pro-gramme of the Agency. We wish Klaus a veryhappy and productive retirement and look forwardto benefiting from his advice from time to time.

I am privileged to have been selected to replaceKlaus as the Section Head. Although it is a toughact to follow, I hope to successfully lead the Sectionin increasing the role of Isotope Hydrology in water

resources management and in advancing the under-lying science.

This issue of the News focuses on isotope studiesrelated to lakes. Physical and bio-geochemical pro-cesses occurring at and below the surface of lakewater influence lake – atmosphere interactions, sur-face and groundwater hydrology, and climaticarchives in lake sediments. Dr. L. Gourcy has pro-vided a review of some of the Agency’s activities inthe development and application of isotope tech-niques to study lake processes. Dr. J. Gibson andDr. T. Edwards from the University of Waterloo de-scribe an improved technique for measuring panevaporation rates. Dr. M. A. Paredes Riveros fromthe Proyecto Especial del Lago Titicaca (PELT) ,Puno, Peru, and Dr. R. Gonfiantini from the Istituto diGeocronologia e Geochimica Isotopica del CNR,Pisa, Italy, describe the use of multiple isotope trac-ers to study the dynamics of Lake Titicaca. I wouldlike to thank all our colleagues for giving so gener-ously of their time to improve the quality of the News.

On behalf of myself and the Section, I wish you all avery happy New Year!

Pradeep AggarwalHead, Isotope Hydrology Section

Contact Us

Isotope Hydrology SectionInternational Atomic Energy AgencyP.O. Box 100, Wagramer Strasse 5

A-1400, ViennaAUSTRIA

Tel. +43-1-2600 + ext Fax: +43-1-26007

Mr. Pradeep Aggarwal , Section Head ,ext. 21735e-mail: [email protected]

Mr. Edmundo Garcia-Agudo, ext. 21739e-mail: [email protected]

Mr. Cheikh B. Gaye, ext. 21733e-mail: [email protected]

Mrs. Jane Gerardo-Abaya, ext. 21742e-mail: [email protected]

Mrs. Laurence Gourcy, ext. 21734e-mail: [email protected]

Mr. Manfred Groening, ext. 21740e-mail: [email protected]

Mr. Yucel Yurtsever, ext. 21732e-mail: [email protected]

Visit Us on the Internethttp://www.iaea.org/programmes/ripc/ih/index.html



Scientific ScopeLakes in a variety of environments (tectonic inclu-ding rift, glacial, coastal, volcanic and fluvial) cover asignificant portion of the surface area of the conti-nent. Freshwater lakes are among the most easilyexploitable freshwater resources. Lakes are alsorecognized as major sedimentological features inwhich stored material can be used to study recentclimate and pollution evolution. To adequately pre-serve these important landscape features, and to usethem as climatic archives, an improved understand-ing of processes controlling their hydrologic and bio-geochemical environments is necessary. The studiesof lake processes can be separated in three cate-gories, with specific isotope applications (Table 1) :

IAEA activities relatedto the study of lakes

Research and Development

The first Advisory Group Meeting (AGM) on the appli-cation of nuclear techniques to study lake dynamicswas held in 1977 at the IAEA Headquarters in Vi-enna. Twenty-four specialists reviewed current re-search trends in order to obtain indications andguidelines for future activities in the field of isotopelimnology. In 1992, a joint UNESCO/IAEA consul-tants’ meeting assessed the new state of the art ofisotope techniques in limnological studies and re-commended a new Co-ordinated Research Pro-gramme. This Co-ordinated Research Programmeon the “Use of Isotope Techniques in Lake DynamicsInvestigations” was initiated in 1994. The programmewas aimed at assessing the potential of environmen-tal isotope techniques in studying the dynamics oflakes and related problems such as solute dynamics,sediment focusing, establishing the water balancecomponents, and vulnerability of surface water bod-ies to pollution. The CRP enabled a number of iso-tope and geochemical studies to be carried out onsmall and large surface water bodies, with the gen-eral aim to better understand the dynamics of thesesystems under growing anthropogenic influence. Acompilation (TECDOC) of the results of this CRP is inpress and is expected to be available in the year2000.

Further improvement of the techniques used for lakestudies is continuing in many laboratories. For waterbalance studies, sampling of water vapour to deter-mine the evaporation factor is difficult to carry out inremote areas where no power supply is available.Development and testing of new techniques for watervapour sampling are on-going at the IAEA and insome other European laboratories. The tritium-heliumisotopes and chlorofluorocarbon concentration meth-

ods have recently been used in many studies todetermine the mixing processes and the apparentage of lake water. For the first time in 1999, suchtechniques were tried in Lake Titicaca where waterbalance parameters are difficult to obtain. Thesedevelopments are expected to provide a better un-derstanding of the lake processes.

Technical assistance on isotopic lake studies

The support of the IAEA to its Member States in lakestudies, through the Technical Cooperation Pro-gramme, is often related to the protection of thewater reservoirs and to understanding the waterdynamics and contamination problems (Table 2).Lakes representing local or regional interests havebeen studied, like lakes Mogan and Eymir in Turkey,Beseka in Ethiopia, Manzala in Egypt, Titicaca inBolivia and Peru, Prespa in the Republic of Macedo-nia, Greece and Albania, and Chapala in Mexico.

Project NIC/8/010 on the study of the water balanceof Lake Xolotlan was of particular interest for thepossibility of determining underground components(groundwater inflow and outflow rates). The waterstable isotopes were used successfully together withpollen, 137Cs and 210Pb of the bottom sediment.Artificial tracers have been used in various countries(Chile, Turkey) to study seepage flow, to determinethe turnover time in lakes, and to identify the possi-ble pollution path.

Another important problem encountered in lake sys-tem is the water level variations. The Caspian Sea isthe world's largest closed basin. The fact that thedrainage basins of its major tributaries (Volga,Ural..) are located in humid climatic regions,whereas the Sea is in the semi-arid zone, makes theCaspian Sea sensitive to hydroclimatic changes.This climatic sensitivity is evidenced above all, in thecontinuous fluctuations of the sea level. Its rapid rise(about 2.25 metres since 1978) is causing greatconcern to all five riparian countries: Azerbaijan,Iran, Kazakhstan, Russia and Turkmenistan. De-spite many years of study, knowledge of the causesof the Sea's water-level rise and fall is still limited,although it has been demonstrated that the waterbudget fluctuations are likely climatically induced. Aregional West Asian project (RAW/8/004) providedsupport for the use of isotopic techniques in tacklingsea level rise and its negative consequences on theeconomies of the riparian countries.

On the other hand, Lake Beseka in Ethiopia pre-sents the particularity of having extended at anastounding rate for three decades. The continuousrise of the lake level creates problem for highways,

ISOTOPE TECHNIQUES IN LAKE WATER STUDIES

Programme Review



Table 1: Role and application areas of isotopesin limnology

Lake Budget* evaporation rate estimation

- 18O, 2H, 3H, 36Cl* precipitation

- 18O, 2H, 3H* underground and subsurface inflow and outflow, origin of water

- 18O, 2H, 3H, 37Cl, 87Sr/86SrLake Dynamics

* horizontal and vertical mixing rates, transit time and water veloc-ity

- artificial tracers; 3H- rare gases; 3He/4He, 20Ne, 222Rn- 226Ra/222Rn- 18O, 2H, 3H

* apparent age/time of segregation of deep water from the atmosphere

- 3H/3He, 36Cl- freons (CCl2F2 and CCl3F)

* redox processes and recycling carbon and lake ventilation- 13C, 14C in DOC and DIC, 3H

* sedimentation rate and migration of sediments on the lake floor (sediment dating)

- 210Pb, 137Cs, 14C, 32Si, 10Be, U/Th series- 13C and 18O of carbonates and dissolved water

* migration of chemical species in sediments and the exchange of different substances between sediments and overlying water

- artificial tracers 3H- anthropogenic radionuclides; 90Sr, 137Cs, 144Ce, 239Pu- natural radionuclides; 7Be, 40K, 210Pb

Contamination- 34S- 15N, 18O

Paleolimnological investigation- reconstructing hydrological conditions; 18O, 13C- ice formation; 18O, 2H

Country Title started

Turkey Study of lakes usingisotope techniques

1993

Nicaragua Evaluation of anthro-pogenic impact onLake Xolotlan

1995

Peru andBolivia

Isotopic and hydro-chemical study of theLake Titicaca

1997

Turkey Nuclear techniques forlake and marine pollu-tion studies

1997

Ethiopia Use of isotopes in thestudy of Lake Beseka

1997

Colombia Hydrodynamics ofLake Tota and theireffect on pollution

1999

MacedoniaGreeceAlbania

Study of the Prespalake using nuclear andrelated techniques

1999

Table 2: IAEA-ongoing TC projectsrelated to lake studies

Programme Review

COUNTRIES W ITH NATIONAL TC PROJECTS IN ISOTOPE LIMNOLOGY (Since 1976)COUNTRIES W ITH NATIONAL TC PROJECTS IN ISOTOPE LIMNOLOGY (Since 1976)

((Source: IAEA TC-Pride Database)Source: IAEA TC-Pride Database)* * former USSR is representedformer USSR is represented

Programme Review



railways and farm lands. Due to high salinity andfluoride concentration, waters of this lake are notconsidered potable. Stable water isotopes, tritiumand carbon-14 of dissolved inorganic carbon wereused to provide conclusive evidence that the lakelevel rise occurred due to a decrease in the lakeoutflow. This outflow decrease resulted from anincrease in the groundwater elevation to the southand east of the lake, most probably due to in-creased irrigation return over the last three

The highly contaminated PunoBay (photo credit : L. Gourcy/IAEA)

decades.

Laurence Gourcy

Serma dam, Yogyakarta, IndonesiaView of the artificial lake. (Photocredit: E. Garcia-Agudo/IAEA)

Serma dam, Yogyakarta, IndonesiaDischarge gauging with artificialtracers. (Photo credit: E. Garcia-Agudo/ IAEA)

Programme Review



LAKE TITICACA: HISTORY AND CURRENT STUDIES

From the early Quaternary, theAltiplano, the flat region at

about 4000 m a.s.l. in Peru andBolivia between the eastern andwestern Andean Cordilleras, wasoccupied by lakes, in shape andextent different from the presentones. The history of these lakes isdocumented by lacustrine sedi-ments.

After the end of the last glaciation,during the Holocene, the Lake Titi-caca attained its present shape, ata mean altitude of 3810 m a.s.l., atotal surface of 8400 km2, and avolume of 930 km3. It consists ofthree main water bodies, thelargest (approx. 6500 km2) anddeepest (288 m) of which is by farthe Lago Mayor in the North, mainlyin Peruvian territory. The LagoMenor (approx. 1400 km2) in theSouth, with a depth of 20-30 m, ismostly located in Bolivia and con-nected to the Lago Mayor throughthe Tiquina Strait which is 850 mwide. The third lake region is theBahia de Puno, a large (approx.500 km2), shallow, highly contami-nated bay in front of the town ofPuno on the western coast of LagoMayor.

Lake Titicaca is the major watersource for about 1,000,000 peopleliving in the lake region. In the na-tive tradition the lake is consi-dereda gift of god, and is invoked byriparians as father of life.

Water balance of Lake Titicaca

As in all closed lakes, the waterbalance of Lake Titicaca is unsta-ble, as indicated by the lake leveloscillations of up to 5 m recorded inthe current century. The minimumlevel (3807 m a.s.l.) was attainedduring the long drought of 1940-1945, and the maximum level(3812 m a.s.l.) was reached in1987 after some rainy years. It istherefore of interest to briefly dis-cuss here the water balance ofLake Titicaca. In fact, a good as-sessment of water inflow and out-flow is of paramount importance forthe lake water management.

Direct precipitation over the lake

provides about 55 % of the waterinflow. On the Altiplano, precipita-tion mainly occurs from Decemberto March, in correspondence withthe astronomic summer and thesouthern shift of the ITCZ(Intertropical convergence zone).The yearly precipitation amounts toabout 700 mm around the LakeTiticaca, and decreases to about400 mm in the South at the latitudeof the town of Oruro, and to 200mm in the salares (salt plains) re-gion. Rains are more abundant onthe lake where they range from 800to 1400 mm/a: this is possibly anindication that part of the waterremoved by evaporation returns tothe lake as rain.

Rivers and streams provide about45 % of the water inflow to LakeTiticaca, i.e. about 20 % less thandirect precipitation, and almost thewhole salt inflow. The major riversare Rio Ramis (mean discharge 74m3/s), Rio Coata (47 m3/s), RioIlave (38 m3/s), Rio Huancané (19m3/s), Rio Suches (11 m3/s), RioKeka, all flowing into the LagoMayor; and Rio Tiwanacu whichflows in the Lago Menor. The dis-charge varies largely in the courseof the year, from practically zeroduring the dry season up to 10times the average discharge in therainy season.

Diffuse groundwater leakage intothe lake from coastal aquifers isbelieved to represent a negligibleterm of water balance.

Evaporation from the lake is strongand accounts for more than 95 % ofthe water losses. Data provided byClass A evaporation pans rangefrom about 2000 mm/a at SuanaIsland and Puno, to 1300 mm/a atConima and Copacabana and 1200mm/a at Isla del Sol. However,these evaporation data are affectedby the pan conditions and tempera-ture variations, which may differconsiderably among stations.Therefore, it is difficult to assessthe lake evaporation rate with suffi-cient accuracy from these data.

Water is removed by Rio De-saguadero (literally: river whichremoves water) from the LagoMenor, which accounts for themissing 5 % of water losses. RioDesaguadero works as an over-flow for the lake and helps toreduce the lake level changes. Itflows towards the South acrossthe Bolivian Altiplano and after400 km reaches the Lake Poopó(3686 m a.s.l.), south of Oruro;the excess water ends up in thesouth-western salar de Coipasa(3657 m a.s.l.). With its limiteddischarge (mean value 30 m3/safter collecting water from smalltributaries all the way from LakeTiticaca to Lake Poopó), the RioDesaguadero is the most impor-tant water resource for the aridBolivian Altiplano.

Evaporation is therefore thelargest water balance term andpossibly the one which shows theleast interannual variability. Un-fortunately, evaporation is alsothe most difficult parameter tomeasure with good accuracy.

The Autoridad Autónoma Bina-cional del Lago Titicaca (ALT)[Binational Autonomous Au-thority for Lake Titicaca]

After the strong drought whichstruck the Altiplano in summer1982-1983 – the rains were lessthan the half of the averageamount, in a possibly fortuitouscoincidence with a strong El Niñoevent – the Peruvian Governmentestablished the Proyecto Especialdel Lago Titicaca (PELT), withHeadquarters in Puno, with thegeneral task of fostering studiesand activities leading to a betterassessment, exploitation andmanagement of the resources ofthe region, including farming, cat-tle breeding, fishery, water re-sources, etc.

About the same time the prepara-tion of a Binational Master Planfor water resources managementand protection-prevention offloods, started with the support of



the European Community. In thefollowing year the Governments ofPeru and Bolivia established theAutoridad Autónoma Binacionaldel Lago Titicaca (ALT) with Head-quarters in La Paz, Bolivia. PELTbecame the executive arm of ALTand was converted into a bina-tional body. The zone of activitywas extended to the whole LakeTiticaca basin which has a surfaceof 144,000 km2 including the Boli-vian Altiplano. Among the PELTundertakings, worthy of mention isthe creation of the lake researchcentre in Chucuito, about 20 kmSouth-east of Puno.

The IAEA Technical CooperationProject RLA/08/022

In December 1997, the Interna-tional Atomic Energy Agencylaunched the Technical Coopera-tion Project RLA/08/022 for the ap-plication of isotope techniques tothe investigation of Lake Titicaca,for which ALT and PELT were themajor counterparts. Other impor-tant counterparts were the InstitutoPeruano de Energia Nuclear(IPEN) in Lima and the Instituto deInvestigaciones Químicas (IIQ) ofthe Universidad Mayor de San An-drés in La Paz. The major objec-tive of the project was to improvethe lake chemical and isotopic bal-ances in order to better assess thewater resources available from thelake. This objective implied the or-ganization of an extensive networkof stations for sampling the lakeand its major tributaries, precipita-tion, groundwater, and the execu-tion of experiments to improve theevaporation estimate. The sam-pling network and frequency wereestablished in 1997, it includes 18lake sites to be sampled bi-annually at various depths, 9 riversand 11 precipitation stations formonthly sampling, and a number ofwells and springs for groundwatersampling.

The activities carried out to presentwith the IAEA support are summa-rized below.

1. About 800 water samples werecollected and their chemical andisotopic composition determined.A first assessment of chemical and

isotopic results is being made. Itwould be desirable, however, thatsampling and measurements con-tinue for some years in order toobtain statistically meaningful data.

2. The PELT boat was equippedwith a new system for deep watersampling by Nansen bottles andwith probes to measure water tem-perature and conductivity at depth.

3. A new evaporation pan was con-structed, in which the water temper-ature is fixed by using the lakewater as thermostatic fluid. The en-ergy for the lake water circulationpump is provided by solar panels.The whole system is now installedand tested in the Taquile island.

4. The equipment of the Instituto deInvestigaciones Químicas was up-graded and strengthened with anew ion chromatograph to copewith the high number of chemicalanalyses to be done. Intercalibra-tion with the chemical laboratory ofthe Istituto di Geocronologia eGeochimica Isotopica (Pisa) is go-ing on.

5. In April 1999, a Regional Courseon Isotope Limnology was held inChucuito on the Lake Titicaca,which was attended by scientistsand technicians from Columbia,Cuba, Mexico, Nicaragua, andVenezuela, in addition of thosefrom Peru and Bolivia.

6. Lake samples were taken for de-termining the freon concentrationderiving from dissolution of anthro-pogenic freon present in the atmo-sphere. Freon concentration is de-termined by gas chromatography atthe IAEA Isotope Hydrology labora-tory.

7. Various fellowships have beenawarded and the training for staffwill continue in 2000.

Preliminary short discussion ofthe Lake Titicaca data

Isotopic and chemical data on LakeTiticaca, obtained within the frameof the IAEA Technical Co-operationproject RLA/08/022 are accumulat-ing, and a preliminary, qualitative

interpretation can be attempted.We summarize below the majorobservations and conclusions, andindicate activities to continue orinitiate.

Closed lakes, where the majorfraction of the inflowing water isremoved by evaporation, exhibit asignificant enrichment in heavyisotopes. This is due to the factthat the isotopically light watermolecules (1H2

16O) evaporatefrom the liquid surface at higherrate than those containing heavyisotopes (2H or 18O), the concen-tration of which increases in theresidual liquid phase. Therefore,Lake Titicaca water, like all closedlakes, is enriched in heavy iso-topes. In particular, the LagoMayor is enriched by about 60 ‰in 2H and 12 ‰ in 18O with respectto rivers and precipitation feedingthe lake. Due to the large size anddepth, and the relatively long resi-dence time of water, the isotopicand chemical composition of theLago Mayor is very uniform andconstant in time.

A further enrichment of about 10-20 ‰ in 2H and 2-3 ‰ in 18O isobserved in water of Lago Menorwith respect to the Lago Mayor,accompanied by a salt concentra-tion and conductivity increase ofabout 20-30 %. The isotopic andchemical composition of the LakeMenor is less stable and uniformthan that of Lago Mayor, due tothe shallow depth and short resi-dence time of water. Isotopic andchemical values similar to those ofLago Mayor are found in theTiquina Strait, while intermediatevalues are observed at the sam-pling site closest to the Strait in theLake Menor. This indicates thatthe water movement is essentiallyunidirectional from the Lago Mayorto the Lago Menor, and there is nosignificant return of water from theLago Menor.

On the contrary, the bulk of PunoBay water is isotopically andchemically almost undistinguish-able from the Lake Mayor, indicat-ing that the water moves in bothdirections, i.e. from the lake intothe bay and vice-versa. The identi-fication of lake water major circu-lation patterns is important not



only for making water balances butalso for predicting the contaminantdispersion and fate.

In all cases, the lake is isotopicallyquite different from groundwater incoastal aquifers (typical values vs.V-SMOW: δ18O –15 ‰ and δ2H–120 ‰), where in principle signifi-cant lake water contributions couldbe easily identified.

As already said, the isotopic andchemical composition values arequite uniform throughout the wholeLago Mayor indicating that the lakeis vertically and horizontally wellmixed. Thus, the application ofmodels based on the isotopic andchemical material balances is quitestraightforward.

More difficult is the estimate ofmean values of input waters, andin particular the mean isotopiccomposition of rains and rivers andthe chemical composition of rivers.Large variations occur for the rainisotopic composition as well as for

the river, in spite of the fact thatchemistry and isotopic composi-tion of rivers are to some extentbuffered by groundwater. This mayrequire a long period of observa-tion, in order to fully understandthe processes governing the iso-topic and chemical variations as afunction of river discharge. To thisaim, the sampling frequency mayneed to be increased duringfloods. Generally speaking, the de-sign, installation and managementof the sampling network may needto be revised on the basis of theacquired experience.

Evaporation rate is the major un-known in the Lake Titicaca bal-ance. Evaporation experiments willbe carried out in the special evapo-ration pans being built for the pro-ject (one is already installed in theTaquile Island). The scope is toestablish the steady state isotopiccomposition of the evaporating wa-ter, and from this to contribute toassessing the characteristics ofthe evaporation pans for determin-

ing the evaporation rate. The newevaporation pans, when availablein sufficient number, will hopefullycontribute to reduce the currentdiscrepancies between measure-ments carried out at different lakestations, thus improving the relia-bility of evaporation rate measure-ments.

Marco A. Paredes Riveros1 &Roberto Gonfiantini2

(1) PELT, Puno, Peru(2) Istituto di Geocronologia eGeochimica Isotopica del CNR,Pisa, Italia

For more information see C. Dejoux and A.Iltis (Editors): Lake Titicaca. A Synthesisof Limnological Knowledge, Kluwier Aca-demic Publishers, Dordrecht, 1992.

Meteorogical station in TaquileIsland, Lake Titicaca (Photocredit : PELT)

ALT/IAEA joint Course on IsotopeLimnology, Chucuito, Peru, 1999Openning ceremony(Photo credit : PELT)



Reliable and consistent characterization of thestable isotope composition of atmospheric wa-

ter vapour and its temporal variability are importantprerequisites to the wider application of isotopemass balance methods in atmospheric and waterbalance studies, at scales ranging from the typicalatmospheric general circulation model (GCM) grid-square domain down to and including field-basedstudies conducted in small watersheds or at pointsnear the ground surface. Precipitation samplingconducted within the WMO/IAEA Global Networkfor Isotopes in Precipitation (GNIP) and affiliatednational networks has made significant contribu-tions to our understanding of temporal and spatialvariations in the isotopic composition of atmo-spheric moisture using the equilibrium assumption,i.e., that the isotope distribution in precipitation is an“equilibrium proxy” for that in vapour, based onassumed temperature-dependent equilibrium iso-tope exchange effects. However, because precipi-tation predominantly occurs as discrete events sep-arated in time, especially in arid or seasonally-aridclimates, liquid-phase sampling may not provide agood time-weighted estimate of vapour-phase iso-topic composition, nor does it provide informationon changes occurring between precipitation events.This is further complicated by uncertainty in therelation between cloud temperature and climatolog-ical temperature, which is difficult to ascertain with-out specific knowledge of the atmospheric bound-ary layer structure. Conversely, improved under-standing of the isotopic relations between precipita-tion and vapour could potentially provide importanthydroclimatological insight, for example yieldingclues about the nature and causes of variations inthe slope of local evaporation lines in δ18O - δ2Hspace, or providing information for evaluation ofatmospheric feedback or throughput in coupledevaporative systems (e.g. Gat and Bowser 1991).

Routine sampling of atmospheric water vapour us-ing cryogenic traps has not been widely adopted infield studies, primarily due to logistical constraints,and it has rarely been integrated within precipitationsampling networks. Moreover, field-based sam-pling campaigns are commonly of rather limitedduration, yielding short-term data sets that mayhave limited applicability at water balance time-scales or may be poorly suited for meaningful com-parison with records of precipitation isotope compo-sition. Challenges also exist to design efficienttrapping systems, because of the potential for frac-tionation arising from incomplete vapour recovery.

Field work in remote areas of continental northern

THE EVAPORATION PAN TECHNIQUE REVISITED: OLDTHEORY AND A NEW APPLICATION FOR TIME-

WEIGHTED SYNOPTIC TRACING OF THE ISOTOPIC COMPOSITION OF ATMOSPHERIC VAPOUR

Canada, an arid region that is typically characterizedby 15-20% wetland area because of underlying per-mafrost, has prompted development of a new ap-proach for characterizing the isotopic composition ofvapour-phase atmospheric moisture and its variability.The method employs conventional evaporation pansand is especially suitable for use in water balancestudies of lakes at local to regional scales. Due to thepronounced seasonality of precipitation, proportion-ately large snowmelt input and short thaw season,lakes in the region rarely attain isotopic steady state,but instead often display systematic seasonal enrich-ments and spatial trends that are strongly dependenton the shifting isotopic composition of local atmo-spheric vapour.

Intensive experiments (Gibson et al. 1999) havedemonstrated that five- to ten-day flux-weightedrecords of the stable isotope content of ambient atmo-spheric vapour can be obtained through careful moni-toring of the isotope and mass budgets of evaporationpans, coupled with the well-known layered resistancemodel of Craig and Gordon (1965). This conclusion isreinforced by successful use of pan-derived vapourδ18O and δ2H values in a detailed isotope-mass bal-ance analysis of a small lake at Lupin, Nunavut, whichyielded evaporation rates in close agreement (±10%)with results based on Bowen ratio energy balance andaerodynamic profile calculations (Gibson et al.1996a,b).

Previous evaporation pan experiments mainly fo-cused on investigation of isotope exchange parame-ters using relatively small pans sensitive to rapidchanges in ambient conditions (e.g. Gat 1970; Wel-han and Fritz 1977; Allison et al. 1979; Allison andLeaney 1982). In contrast, the new approach utilizesstandard class-A pans, which have sufficient volume(220 l) to buffer short-term transient variations inatmospheric conditions, justifying the assumption ofconstant kinetic isotopic fractionation effects in con-cert with precisely measured temperature and relativehumidity to derive vapour isotopic composition.

A major strength of the method is that pan-derivedvapour isotopic compositions are naturally flux-weighted, as represented in the Craig and Gordon(1965) model, and can thus be applied directly toisotope mass-balance analysis of nearby lakes. For-tunately, although the use of kinetic isotope effectsthat are inherently dependent on the turbulenceregime of the boundary layer is a potential weakness,

Technical Review



Technical Review

this factor seems to be remarkably uniform onsynoptic time scales or, alternatively, it can beindexed on the basis of other routinely measuredclimatological data.

As an example, Figure 1 shows a comparison ofpan-derived atmospheric vapour δ18O and δ2H atthe Lupin study site with data obtained from cyro-genically trapped vapour during the daytime andcalculated vapour δ18O and δ2H assuming isotopicequilibrium with discrete occurrences of precipita-tion. The pan-derived values clearly provide com-parable records of temporal changes in atmo-spheric moisture δ18O and δ2H. Note that thedaytime vapour-trap estimates are biased relativeto the daily pan-derived estimates because of theinfluence of vapour from local lakes and tundrabryophytes.

The results suggest that isotopic sampling of exist-ing, conventionally operated class-A evaporationpans could offer a straightforward and cost-effective solution to the problem of documenting theshifting isotopic distribution in atmospheric mois-ture. The method could provide continuously-weighted records of vapour δ18O and δ2H for use inisotope-climate research, which would be of partic-

ular value for stations receiving little or highly variableprecipitation. As studies in Canada have shown,such data are applicable in hydrometeorological stud-ies at various spatial and temporal scales. Significantpotential also exists for incorporation into major inter-national hydroscience initiatives, like the ongoingcontinental-scale regional hydrologic studies withinthe Global Energy and Water Cycle Experiment(GEWEX), as well as being a resource for validationof the global isotope field as depicted by atmosphericGCMs field as depicted by atmospheric GCMs.

References

Allison, G.B. and Leaney, F.W. 1982. Journal of Hydrology 55,

151-161.

Allison, G.B., Brown, R.M. and Fritz, P. 1979. Journal of Hydrol-

ogy 42, 109-127.

Craig, H. and Gordon, L.I. 1965. In: E. Tongiorgi (Editor), Stable

Isotopes in Oceanographic Studies and Paleotemperatures,

Lab. Geologia Nucleare, Pisa, 9-130.

Gat, J.R. 1970. In: Isotopes in Hydrology, 1970. IAEA, Vienna,

151-162.

Gat, J.R. and Bowser, C.J. 1991. . In: H.P. Taylor, J.R., O’Neil,

and I.R. Kaplan (Editors), Stable Isotope Geochemistry: A

Tribute to Samuel Epstein, Special Publication No. 3, The

Geochemical Society, San Antonio, Texas, 159-168.

Gibson, J.J., Prowse, T.D. and Edwards, T.W.D. 1996a. Hydro-

logical Processes 10, 1369-1382.

Gibson, J.J., Prowse, T.D. and Edwards, T.W.D. 1996b. Nordic

Hydrology 27, 1-24.

Gibson, J.J., T.W.D. Edwards and Prowse, T.D. 1999. Journal of

Hydrology 217, 55-74.

Welhan, J.A. and Fritz, P. 1977. Geochimica et Cosmochimica

Acta 41, 682-686.

J.J. Gibson and T.W.D. EdwardsDepartment of Earth Sciences

and Environmental Isotope LaboratoryUniversity of Waterloo,

Waterloo ON N2L 3G1 CANADA

δ 1

8 O (‰

)

- 4 2

- 3 8

- 3 4

- 3 0

- 2 6

1 9 9 2

1 8 0 1 9 0 2 0 0 2 1 0 2 2 0 2 3 0 2 4 0

δ

2 H (‰

)

- 2 6 0

- 2 3 0

- 2 0 0

- 1 7 0

δ 18

O (‰

)

- 4 2

- 3 8

- 3 4

- 3 0

- 2 6

1 9 9 3

1 9 0 2 0 0 2 1 0 2 2 0 2 3 0 2 4 0

δ 2

H (‰

)

- 2 6 0

- 2 3 0

- 2 0 0

- 1 7 0V A P O U R T R A P

D a y o f Y e a r

Figure 1. Time-series of step-wise atmosphericvapour δ18O and δ2H values derived from class-Apans (solid lines), average of moisture collected dailyin vapour trap at height of 6-m over tundra (boldlines), and estimates of vapour δ18O and δ2H basedon the assumption of isotopic equilibrium with dis-crete occurrences of precipitation (diamonds). (SeeGibson et al. 1999.)

Technica Reviewl



GROUNDWATER RENEWAL IN WATERSCARCE AREAS

The final coordination meeting of the CRP enti-tled “Isotope based assessment of groundwa-

ter renewal rate in water scarce areas” was held inVienna, from 18 to 21 October 1999. FourteenInstitutes were involved in this project which is nowclosed. Detailed information on physiography,lithology, rainfall, unsaturated zone moisture con-tent and a variety of chemical and isotopic con-stituents was collected at a total of 44 benchmarksites located mainly in arid regions. The purposewas to evaluate the use of chemical and isotopictools to understand history of recharge and to esti-mate recharge rates. Evaluation of chloride andtritium concentrations from unsaturated zone pro-files (up to a depth of 45 m) provided recharge rateestimates ranging from fractions of a millimetre totens of millimetres per annum. The methodologyadopted and verified through applied field researchhas proved the applicability of unsaturated zoneisotopic/hydrochemical profiles for estimation ofnatural renewal rate of aquifers in such arid re-gions, and has provided a unique approach for thispurpose. The results and findings of the CRP will bepublished as a TECDOC by the Agency in 2000.

Y. Yurtsever

ISOTOPE RESPONSE TO DYNAMIC CHANGESIN GROUNDWATER SYSTEMS DUE TO

LONG-TERM EXPLOITATION

The first Research Co-ordination Meeting of therecently initiated CRP entitled “Isotope response

to dynamic changes in groundwater systems due tolong-term exploitation” was held in Vienna, from 8 to12 November 1999. The main motivation for theinitiation of this CRP was the fact that during the lastfew decades major sources of freshwater have beenexploited to meet the ever increasing demand forwater supply to different sectors (domestic, agricul-tural and industrial). The stresses imposed on theavailable water resources due to man’s impact(exploitation, release of pollutants through domestic/industrial waste waters, and agricultural practices)have resulted in many parts of the world in depletionof the available reserves as well as the deteriorationof water quality. This impact is more pronounced inarid and semi-arid regions. Therefore, the CRP isdirected mainly towards making an assessment of thepotential utility of isotopes in the quantitative under-standing of the long-term changes induced by ex-ploitation. Furthermore, applied field research in se-lected bench-mark systems with different hydrogeo-logical settings and spatial scales will enable method-ological developments for more reliable predictions offuture behaviour of the systems under different ex-ploitation scenarios.

Y. Yurtsever

CRP NEWS

ISOTOPE HYDROLOGY CALENDAR

2000

IAEA MEETINGS AND TRAINING

February

Advanced course on numerical modelling -RAS8084 - Bangkok, Thailand, 14 - 25

IAEA Meeting Categories

AGM: Advisory Group Meeting;RCM: Research Co-ordination Meeting;CS: Consultants Service;CM: Consultants Meeting;SYM: International Symposium

March

RCM on The use of tracers and stable isotopes insurface water pollution, RC-701.2 - Vienna,13 - 17

April

Executive Meeting for Water Resources Managers,RAS/8/084 - Taejon, ROK



GNIP-SCIENTIFIC STEERING COMMITTEE MEETING

On 1 and 2 July 1999, the firstmeeting of the Global Network

for Isotopes in Precipitation - Scien-tific Steering Committee (GNIP-SSC) was held at the IAEA Head-quarters in Vienna. The scope ofthe GNIP-SSC, as defined in theMemorandum of Understanding re-lating to GNIP signed by the IAEAand the WMO, is to “provide adviceto the IAEA and WMO on mattersrelated to the GNIP and to theGNIP Data Base”.

The main recommendationsmade by the Steering Committeeare:

- WMO/IAEA should consider ap-proaching meteorological/hydrolog-ical services to help in the manage-ment of national networks.

- A list of national networks onisotopes in precipitation should becompleted.

- IAEA should compile all the publi-cations using the GNIP data, andthis list should complete the infor-mation given to the national net-works and GNIP stations.

- The SSC recommended includingscientists from other continents(Asia, Australia, South America) inthe SSC.- The SSC asked that a task group

be formed to consider the gapsand needs for more stations.

- Some regions have already beenidentified and should be contactedin order to start/continue sampling(Brazil, tropical Andes, WestAfrica, India, Central Asia).

- The SSC recommended that thenetworks of Global AtmosphereWatch (GAW) of WMO be used asmuch as possible for the GNIPnetworks.

Composition of the first GNIP-Scientific Steering Committee

The first committee members havebeen selected in order to present agood equilibrium between scien-tifics from the United Nationsagencies and scientifics from re-search institutes. Both climatolo-gists and hydrologists are repre-sented. The SSC expressed inter-est in having additional membersof the hydrological/hydrogeologi-cal communities in the GNIP com-mittee.

* IAEA

- Head of the Isotope HydrologySection

- Isotope Hydrology Section staffin charge of the GNIP

* WMO

- Director of the WCRP

- to be suggested by WMO

* IGBP / PAGES

- to be suggested by PAGES

* Experts representing the sci-entific community

- Environmental Physics:U.Schotterer, ISOHYC, Switzer-land

- Meteorology:S. Hastenrath, University ofWisconsin-Madison, USA

- Climatology:M. Latif, Max Planck Institute forMeteorology, Germany

The full report of the first GNIP-SSC and more information aboutthe Global Network for Isotopes inPrecipitation can be requestedfrom Laurence Gourcy

[email protected]

ISOTOPE HYDROLOGY INFORMATION SYSTEM ISOHIS

The ISOHIS database allow gathering, storageand dissemination of isotope, chemical, hydroge-

ological and geographical data from water studiesaround the world. The software for entering andverifying records, and for managing local/regionaldatabases called Data Entry Module is availablesince May 1999.

You can download directly the software and UserManual in ftp://ftp.iaea.org/dist/isohis/ or requestthe CD-ROM from Laurence Gourcy.



GEOTHERMAL ENERGYRESOURCES - RESULTSAND ACHIEVEMENTS

Aworkshop to assess this re-gional project was held in

November 1999 in Indonesia.The workshop was attended byrepresentatives from China, In-donesia, Philippines and Thai-land, who collaborated in theproject, as well as by counter-parts of on-going IAEA Techni-cal Cooperation projects ongeothermal energy in El Sal-vador, Costa Rica, Ecuador,Peru and Guatemala.

Regional Project RAS/8/075was implemented with the gen-eral objective to support the uti-lization of isotope and geochem-ical techniques for geothermal

reservoir management.The project included three sets ofactivities :

• Field investigations using isotopeand geochemical techniques for theexploration of low-medium tempera-ture geothermal systems, commonlyoccurring hydrological problems as-sociated with exploitation and rein-jection in high temperature systems,as well as environmental impactsdue to waste water reinjection on theshallow groundwater.

• Interlaboratory comparison whichassessed the quality of chemical andisotope analyses in the participatinglaboratories.

• Development of a regionaldatabase on geothermal waters as apre-requisite to planning and ma-

ISOTOPE FOR IMPROVEDDRINKING WATER

REOURCES MANAGEMENT

The first assessment work-shop of the UNDP/IAEA/RCA

Project RAS/8/084 was held inVietnam from 27 September to 8October 1999.

A workshop reviewed the resultsof Interlaboratory comparison forchemistry. The role, strategy, de-sign and concepts in isotope in-vestigations, formulations of con-ceptual models for quantitativeinterpretation of isotope data inhydrology, and general modelling

concepts for isotope data interpre-tation in groundwater hydrologywere discussed. The various ap-proaches to data processing andinterpretation were exposed duringthe presentations and will be usefulfor participants to consider in theircontinuing investigations.

The participating countries are en-couraged to facilitate transfer oftechnology through regular com-munication. Countries with estab-lished expertise in the fields of iso-tope hydrology and modelling reit-erated their willingness to impartinformation to less experiencedMember States.

nagement of the geothermal re-sources.

The regional programme reco-gnized the availability of scientificexpertise in the countries of theregion. Manpower resources havebeen developed, information ex-changed and disseminated, and theapplications of isotope techniquesto practical hydrological and geo-chemical problems associated withexploration and management ofgeothermal reservoirs accelerated.The regional collaboration has har-nessed and optimized the availableexpertise in participating countriesconsistent with the intentions ofTCDC.

J. Gerardo-Abaya

The initial training and hands-onexercises on numerical modellingwere provided on MODFLOW andMT3D which will be used in theproject for development of site-specific dynamic simulation modelsfor groundwater flow and transportfor the study sites included into theproject. The lectures and computerexercises provided the capabilitiesfor use of the software, includingdata input, simulation, calibrationand post-processing of the simula-tion results.

Y. Yurtsever/J. Gerardo-Abaya

WORKSHOP ON ISOTOPEDATA INTERPRETATION -

PROJECT RAF/8/029

Aregional workshop on IsotopeData Interpretation and Inte-

gration in site conceptual modelswas held from 27 September to 8October at the Schonland Re-search Centre, University of Wit-watersrand, Johannesburg, SouthAfrica. The Course was organisedwithin the framework of the ongo-

ing regional Technical Co-operationModel Project RAF/8/029 and wasattended by 14 participants fromthe 7 countries involved in the re-gional project, namely Kenya,Madagascar, Namibia, SouthAfrica, Tanzania, Uganda and Zim-babwe. In addition to provision oftraining, the workshop was alsoaimed at reviewing the status of theModel Project and updating theworkplan.The workshop provided a detailed

overview of the principles and ap-plications of isotope hydrology.Lumped parameter models to in-terpret groundwater isotopic dataas well as hydrologic models wereintroduced with emphasis on thehands-on use of MULTIS andVISUAL MODFLOW. The IsotopeHydrology Data base (ISOHIS) de-veloped by the Isotope Hydro-logySection of the IAEA was also intro-duced.

C. B. Gaye

TC ACTIVITIES



2nd INTERLABORATORY COMPARISON FORDEUTERIUM AND OXYGEN-18

ANALYSIS OF WATER SAMPLES

The IAEA Isotope Hydrology Laboratory orga-nised in 1998/99 the 2nd interlaboratory com-

parison test for the analyses of hydrogen andoxygen isotope composition of water. The test wasopen to all laboratories engaged in isotope analy-ses of water samples world-wide.

The main objective of this exercise was to help thelaboratories to assess their precision and accuracyfor the range of δ

18O and δ

2H values normally

observed in meteoric waters. More than 115 labo-ratories from 43 countries indicated their willing-ness to participate in the exercise and receivedfour water samples (OH-1 to OH-4) for analysis.

STATISTICAL EVALUATION OF THE RESULTS

During this intercomparison exercise all partici-pants remained anonymous. Their full addressesare listed in the Annex of the Report, but no link totheir identifying lab number used in the data pre-sentation is given (except the IAEA laboratory,ID no. 10). Only the participants were able to iden-tify themselves. By the end of April 1999, 87 of theparticipating laboratories had reported their data.

Results of seven laboratories, selected by theIAEA for their high analytical quality, were used toassign a “consensus” value for the analyses withthe lowest attainable uncertainty.

Figure 1 is an example of the way the evaluateddata set was presented in the IAEA report. Theδ18O-values of the sample OH-1 are sorted inascending order and plotted versus the laboratoryID numbers. Vertical bars indicate the standarduncertainty (1 σ) quoted by each laboratory. Thesolid line represents the adopted consensus value.The dotted line represents the weighted meanvalue as calculated from the whole set of laborato-ries with the standard uncertainty indicated by thetwo dotted lines. The data presentation in such anS-shaped plot shows the large number of laborato-ries participating in the intercomparison exerciseand the range of values reported by these laborato-ries. Full circles indicate the accepted values, opencircles indicate the rejected outliers. Visually, onemight notice the importance of the reported stan-dard uncertainty of each laboratory in respect tothe rejection of values: Deviating values might stillbe accepted as long as the laboratories state areasonable uncertainty and vice versa.Finally, one should realise the shift between theconsensus value (solid line) and the weighted

mean of the whole group (dashed line). This shifttowards more depleted values is systematically foundfor all four water samples and might be explained byevaporation of improperly stored internal standards.

CONCLUSIONS

The participating laboratories are a representativeportion of the entire analytical community engaged inthis type of measurements. Therefore, it is believedthat the results of this test properly reflect the currentsituation with respect to accuracy and precision ofstable isotope analyses of water samples.

The apparent interlaboratory precision (one-sigmalevel), derived from the whole pool of the analysedresults, is in the order of 0.11 ‰ for δ

18O and 1.3 ‰

for δ2H. This is comparable with the typical standard

precision reported by the majority of the laboratories.

• No major improvement of this performance indica-tor could be detected with respect to that in 1995 (1st

interlaboratory comparison).

• At least 25% of the participating laboratories under-estimate their overall standard uncertainty and/orsuffer from systematic effects of varying nature andare therefore identified as outliers (fig. 1, open cir-cles).

• No significant dependence of the obtained δ-valueson the type of the sample preparation procedurecould be detected.

LABORATORY ACTIVITIES

105 21 106

107

136

128 25 93 33 69 131 42 83 75 114 64 16 14 47 73 88 28 123

116

117 79 113 27 52 61 109 15 71 132 96 24 126 36 46 17 32 53 78 129 82 58 111 62 39 44 101 54 26 31 99 121 10 13 125

34a

67a 19 115 43 65 55 51 29 108 72 68 35 97 22 127

137 86 12 122 45 85

Laboratory identification number-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

δ18O

[‰]

accepted values

rejected outliersWeighted mean value

Standard deviation (1σ)of the weighted mean value

Consensus Value

IC-OH-1 δ18O [‰]: - 0.05 +/- 0.01 [‰]

reported standard uncertainty (1σ)

Figure 1: S-shape plot of δ Deuterium values sample OH-1 in ascending order versus the Laboratory Identification numbers. For explanations see text.



• The results for the entire population do not shownormal distribution. A small but significant shifttowards more negative δ-values between the con-sensus value and the weighted mean value of theentire population is identified. Since an evapora-tive loss of only 0.1% of the initial mass of the usedinternal standard or of an improperly stored VS-MOW sample would be sufficient to explain theobserved isotope shift in the observed order of0.04 ‰ for δ

18O and 0.3 ‰ for δ

2H, such an evapo-

rative enrichment with time after the calibrationagainst VSMOW might be one possible explana-tion.

The final report “IAEA 2nd Interlaboratory Compari-son for Deuterium and Oxygen-18 Analysis of WaterSamples” will be made available as PDF documentfor download on the homepage of the IAEA IsotopeHydrology Laboratory under: http://www.iaea.or.at/ programmes/rial/pci/isotopehydrology/hydrology_ main.htm

J. Lippmann / M. Gröning

AGM NEWS

CHALLENGES AND NEW TECHNIQUES FOR LIGHT ELEMENTSTABLE ISOTOPE MEASUREMENTS

An Advisory Group Meeting on Stable IsotopeRatio Measurements by GC-IRMS and Laser

Spectroscopy was held from 20-23 September1999 in Vienna. The meeting aimed to review thecurrent status of emerging techniques for the deter-mination of stable isotope ratios of light elements.Besides isotope hydrology and isotope geoche-mistry, the range of disciplines using isotope signa-tures has broadened significantly during the lastyears, adapting and using isotopes to, for example,characterise physiochemical or biological path-ways, fingerprint substances and trace materialfluxes. As a consequence, the requirements of theinstruments have changed significantly in somefields. Several new instrumental developmentswere discussed in the meeting with a focus on (1)Continuous Flow-Isotope Ratio Mass Spectrome-ters (CF-IRMS) and (2) optical techniques for sta-ble isotope determinations.

Continuous Flow IRMS is a generic term for IRMSinstruments coupled on-line to preparation or sepa-ration systems like Elementary Analysers, GasChromatographs, and Combustion or ReductionInterfaces. The key features of CF-IRMS includereduced sample size and analysis time and isotopemeasurements of individual compounds in com-plex mixtures.

Optical techniques use laser beams for measuringthe absorbance of different spectral lines for thevarious isotope species, e.g. 12C16O16O vs.13C16O18O, in the infrared region or for measuringthe electrical response of gas discharge to opticalperturbation. Various detection techniques areused, with significant improvements realised re-cently, offering some operational advantages suchas simplified instrumentation, multiple simulta-

neous measurements, non-destructive determina-tions and reduced contamination risks, e.g. avoidingany isobaric interference. Even though tey are rela-tively young techniques, the analytical precision isnot far from that achievable with mass spectrometrytechniques. Further improvements are expected inthe future, which will make these techniques widelycompetitive to mass spectrometry. Despite recentimprovements, the measurement of stable isotopesis still reported as ratios relative to standards ofknown isotope ratio. The creation of reliable isotopestandards or international reference materials forboth techniques is critical not only to compare re-sults between runs on a single machine, but also torelate them to other machines and laboratories. Therequirements for isotope standards have increaseddramatically with the new technologies, also due tothe wider range of applications. As a result, there arenew challenges for the isotope community to extendthe availability of international reference materials.This meeting defined the most urgent needs for suchmaterials and gave a starting point for a new fieldand direction for the Stable Isotope Reference Mate-rials Program of the IAEA.

M. Gröning



Water and Environment News, Isotope Hydrology Section, International Atomic Energy Agency, WagramerStrasse 5, P.O.Box 100, A-1400, Vienna, Austria. Printed by IAEA in Vienna

STAFF CHANGES IN THE ISOTOPE HYDROLOGY SECTION

Dr. Klaus Froehlich retired from the Agency at theend of July. Dr. Froehlich joined the Agency in1988 as senior staff of the IHS and served asSection Head for the last five years. During histenure as Section Head, he facilitated efficientcollaboration with colleagues world-wide to fosterfurther development and application of isotopetechniques in hydrology and related environmentalfields. Isotope Hydrology has increased its visibilityamong the Member States, and the programmewas recognized by the General Conference as asignificant achievement of the Agency. Amongother initiatives, he was responsible for conceivingand launching Water and Environment News, es-tablishing a Memorandum of Understanding on theGlobal Network for Isotopes in Precipitation (GNIP)between the IAEA and the WMO, and providing theGNIP database through Internet to the scientificcommunity. He also initiated the setting up of theIsotope Hydrology Information System (ISOHIS).During the last two years he enhanced effortstowards launching a long-term Inter-Agency(UNESCO, WMO, WCRP etc.) collaborative pro-gramme called International Programme for Iso-topes in the Hydrological Cycle.

He can be contacted at the following address :Viktor-Wittner-Gasse 63/7A-1220, Vienna, Austriae-mail : [email protected]

Mira Gattin left the IAEA at the end of December1999 after working in the Isotope Hydrology Labora-tory for more than 30 years. As a chemical engineershe started to work on tritium analysis and switchedlater to stable isotope mass spectrometry, where shewas responsible mainly for sample analyses for δD,δ13C and δ18O. At the same time she was responsiblefor the training of many dozens of fellows in the fieldof stable isotope mass spectrometry. Her engage-ment, careful work attitude and friendly personalitycontributed considerably to the success of the labo-ratory. We wish her all the best for the new phase oflife after her retirement.

99-0

0301

Departures:

Arrival:

Michael van Duren joined the Isotope HydrologyLaboratory in December 1999. By profession, he isa food chemist and previously worked in variousbranches of the Agency’s Laboratories in Seibers-dorf for the past 15 years. He will ensure thecontinuity in mass spectrometric measurements inthe Isotope Hydrology Laboratory.

He can be contacted at :Telephone : +43-1-2600-21765e-mail : [email protected]

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