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At the Stable Isotope Laboratory at Rijeka University (SILab Rijeka) we monitor the stable isotope composition (δ18O, δ2H) of precipitation in Croatia. Our data base contains about 50 stations distributed all around the country. Their different latitudes, longitudes and altitudes give information in great detail, including the influence of the topographic structure on the precipitation in this south-eastern part of Europe, as well as the complex interplay of the different climate conditions in the area. Within a few hundred kilometers, the stable isotope values display a significant change from the maritime character in the South (mean δ18O around –6 to –8 ‰) to the continental behavior in the North (mean δ18O around –8 to -11 ‰). In addition, depending on the location, the mean δ18O values vary with altitude at a rate between approximately −0.2‰ /100m to −0.4‰ /100m, respectively. Particular attention is given to the correlation between δ18O and δ2H (the Local Meteoric Water Line, LMWL), as well as the d-excess d = δ2H − 8٠δ18O.

Mt. Velebit is a 145 km long mountain in the Croatian Dinaric Karst lying between Adriatic Sea and the Ličko and Gacko Polje fields. The massif is built of thick carbonate deposits from the upper Triassic, Jurassic and Cretaceous ages. In higher parts of the massif, the mentioned rocks are covered with younger Oligocene to Lower Miocene carbonate breccias, probably deposited on the flanks of tectonically uplifted areas during older tectonic phases. Owing to its position between Adriatic Sea and continental Lika region, as well as altitudes up to 1757 m, the mountain also serves as an important climatological border causing high precipitation rates (>3500 mm/y). A more than 2000 meters thick karst rock succession caused very deep karstification was controlled by Adriatic Sea level during Pleistocene and tectonic structures of the massif. The discovery of many vertical and deep caves in last decades (including the deepest and longest caves in Dinaric karst: 1431 m deep Lukina jama, 1321 m deep Slovačka jama and 1026 m deep Cave system Velebita) gives us the opportunity of gathering new insights on karst hydrology. We used stable isotopes of oxygen (18O, 16O) and hydrogen (2H, 1H) in water as environmental tracers to get an insight into the functioning of different karst subsystems of Mt. Velebit. Ratios of these isotopes (18O/16O, 2H/1H), and consequently δ18O and δ2H water values, depend on various factors: precipitation origin, re- evaporation, re-condensation, season, terrain altitude, etc. Therefore, the stable isotope composition of precipitation and karst groundwater may reveal information such as: mean recharge area elevation, importance of winter and summer recharge precipitation of a karst system and average duration of water retention in a system. We compared the stable isotope content of monthly precipitation samples with that of groundwater samples collected in caves, and spring water samples collected at the main discharge points of this complex karst system that belongs to the massif. The stable isotope measurements were conducted using the water equilibration technique performed on Delta plus XP isotope ratio mass spectrometer (Thermo Finnigan) in conjunction with HDOeq42/24 (IsoCal) equilibration unit and Dual Inlet system (Thermo Finnigan) peripherals.

Several karst springs in the Gacka area of Croatia were studied using environmental tracers (stable isotopes (18O, 2H), tritium (3H), chlorofluorocarbons (CFCs) and noble gases (3He, 4He, Ar, Ne, Kr, Xe)). They provided valuable information regarding the mean residence time and age distribution of the spring waters. The variation of the precipitation’s isotopic signal in spring discharge indicates mixing of waters with different transit times. Comparison of CFC and 3H/3He data reveals that during the dry weather period some space in the karst groundwater systems is not filled with water. The results show that compared to single-tracer studies, multitracer techniques may allow a better understanding and characterization of the system.

Upotreba H2, O18, tricija, helija3, rijetkih plinova i CFC za određivanje starosti podzemnih voda nova je tehnika čije su prednosti i ograničenja tek istražuju. Primijenili smo je na istraživanja izvora Gacke (hrvatski krš) i dobivene procjene starosti usporedili sa rezultatima modela izračunatog pomoću stabilnih izotopa H2 i O18 i tricija.

The upper (northern) Adriatic is very rich in precipitation. This input into the water system and its stable isotope composition is a basic factor, knowledge of which is required for proper use and management of water resources. The geomorphology of the region (e.g., mountains of 1400 m next to the sea) can cause specific local conditions. The isotopic composition of precipitation has been measured in various locations at different altitudes. For δ18O this ‘altitude effect’ is found to lie around −0.2‰ /100 m ; its exact value depends on the specific location and the season. The δ2H values and the d-excess vary correspondingly.

Sanitary protection zones of potable water springs in karst areas represent the most widespread protection areas related to protection of the water systems. Karst aquifers are, due to the rapid reaction to the precipitation inputs and weak self-purification capacity, highly vulnerable to pollution. Determining the water origin and aquifer recharge areas is important for karst aquifer protection. Stable isotopes of hydrogen and oxygen, as natural tracers, have been proven to be useful in determination of the above mentioned parameters. We present an example of stable isotopes study for springs Zvir and Marganovo and six wells of Zvir II that are located in an underground gallery. All of them are connected to the river Rječina system. The spring Izvor Rječine is the backbone of Rijeka town’s water supply during the periods of high water and the spring Zvir during the dry months. Zvir II and Marganovo are not included in the water supply system.

The precipitation as input into the water system and its stable isotope composition has to be known for the proper use and management of water resources. The Kvarner bay is a particularly interesting example due to its climate and the geomorphology, featuring high mountains quite close to the Adriatic Sea. The influence of elevation on the isotopic composition has already been examined for Mountain Učka ; a mixing layer of the precipitating air mass on the very top has been found to cause a deviation from the approximately linear behaviour of the δ18O altitude effect. A further specific local condition in the area is the comparatively large amount of precipitation (up to about 1600 mm/year, usually concentrated in a few months during the colder season). This amount effect is known to have a significant influence on the isotope composition of the precipitation, too, in general causing a depletion of the heavier isotopes δ18O in the order of −0.1‰ /100mm. We have now established a rather large density of precipitation collection stations in this area to obtain a better insight into the expected and possibly strong δ18O variations within short spatial distances. Depending on the exact location, the mean δ18O values vary with altitude at a rate of approximately −0.2‰ /100m. Also δ2H and the deuterium excess d = δ2H − 8δ18O is found to depend on location and altitude.

This is a comment on the paper "Definition of the river Gacka springs subcatchment areas on the basis of hydrogeological parameters"

Opća skupština Ujedinjenih naroda je 2013. godinu proglasila Međunarodnom godinom suradnje na području voda. Cilj ove međunarodne godine je potaknuti razvoj multidisciplinarnog pristupa u proučavanju voda i implementaciju saznanja dobivenih znanstvenim istraživanjima u gospodarstvo, međunarodnu suradnju, obrazovanje, komunikaciju i kulturu. Laboratorij za Stabilne Izotope Medicinskog fakulteta u Rijeci od 2010. godine surađuje s komunalnim društvom zaduženim za vodoopskrbu riječkog područja i Zavodom za hidrotehniku i geotehniku Građevinskog fakulteta u Rijeci na istraživanju izvorišta pitke vode grada Rijeke i okolice. Ova suradnja rezultirala je s nekoliko znanstveno-stručnih publikacija i kongresnih priopćenja. U razdoblju od dvije godine prikupljeno je više od tisuću uzoraka oborina i izvorske vode, čiji je izotopni sastav mjeren na masenom spektrometru izotopnih omjera DeltaplusXP, uz prethodno prevođenje uzoraka u plinovito stanje na perifernoj jedinici HDOeq48/24. Na taj način dobivene vremenske serije stabilnih izotopa analizirane su statističkim metodama koje uključuju Box-Jenkins modeliranje i dekompoziciju gustoća vjerojatnosti. Takva analiza omogućila je dobivanje informacija o retencijskim sposobnostima vodonosnika, brzini rekacije na oborinske ulaze, međusobnoj povezanosti izvora, te su, u skaldu sa dopuštenom analitičkom pogreškom, identificirane vodne mase koje doprinose ukupnom toku na izvorima. Vrijeme prikupljanja uzoraka obuhvatilo je periode visokih voda kao i periode suše što je dalo uvid u ponašanje sustava u ekstremnim uvjetima. Dobivena saznanja važna su sa akademskog gledišta u smislu da je na navedenim izvorištima po prvi puta provedeno sistematsko istraživanje stabilnog izotopnog sastava vode, ali i sa praktičarskog aspekta što će biti prikazano na primjerima njihove primjene u vodnom gospodarstvu, javnom zdravstvu, ekologiji i medicini.

Karst water systems are notoriously difficult to describe due to their complex subterranean networks ; springs may be fed not only by large reservoirs, but also through fast channels. This requires an analysis of many experimentally accessible quantities together with rather elaborate model calculations. The Gacka River area is an important Croatian karst water system with multiple springs, exposed to a complex mountain-continental climate with Maritime influence. In a combination of isotopic, meteorological and hydrological data we were able to extract quite detailed information. Gacka River has over 20 (partly intermittent) springs, of which the eight most important ones were sampled in this study. Beside the usual quantities as temperature, pH value and electrical conductivity, the sampled waters were analyzed for their 2H, 18O, noble gas, 3H and CFC content The stable isotopes δ2H and δ18O were analyzed at the Stable Isotope Laboratory SILab ; the CFC, 3He and 3H analyses have been performed by the IAEA Vienna. Five out of eight springs have nearly identical delta values indicating that they are connected to the same reservoir. The δ18O values were used to determine the mean catchment altitudes. The stable isotope delta values of all springs are varying in a narrow range although the recharge isotope signal has a time variable oscillation. This dampened stable isotope signal of the karst groundwater demonstrates the good mixing in the aquifer. In addition, it gives a first indication that the mean ground water residence time MRT of most springs is longer than a few years, with only one of the studied springs having a short MRT of about 1 year. Quantitative MRT values for karst springs can be obtained from unsteady state lumped tracer modeling applications.

The water supply system of the city of Rijeka and surrounding towns mostly relies on the biggest spring in the Kvarner area: Izvor Rjecine. In dry periods, however, when demands for potable water are increased, Izvor Rjecine dries out and several other springs are included into the water supply system. Big amounts of rain after the dry period are characteristic for the area under investigation, and that is when karst springs are most sensitive to potential contamination. Groundwater samples from the above mentioned springs were collected at weekly intervals over a 20-month period. During the same period, monthly and daily precipitation samples were collected. The data set includes a period of above-average precipitation in September 2010, as well as an extremely dry period in August 2011. The stable isotope composition of precipitation was analysed. In groundwater, beside stable isotopes, we also measured the temperature, electrical conductivity, hardness, turbidity, salinity and BOD5. The statistical interpretation of the obtained time series includes multivariate analysis, cross-correlation and Box-Jenkins method for ARIMA process modelling. Information about springs’ reaction time on the meteorological input and therefore on the possible contamination input were obtained. Seasonal behaviour of the stable isotope composition of spring water indicates MRT of the water shorter than 5 years. Reaction of the springs on storm events confirms the dual porosity concept of the karst system. Isotopic altitude effect of precipitation was used to determine mean recharge altitudes of the springs.

U kršu su smještene velike svjetske zalihe podzemnih voda. Zbog posebnosti i kompleksnosti krša znastvenici u njegovu opisivanju pribjegavaju modelima crne kutije u kojem ulazni podatak čine oborine, a izlazni podatak se dobiva na izvorima. Stabilni izotopi kisika i vodika služe kao idelani prirodni obilježivači vode. Poznavanje stabilnog izotopnog sastava oborina i podzemne vode, između ostaloga, omogućuje zaključke o srednjoj visini prihranjivanja vodonsonika, o podrijetlu vode i mogućim povezanostima među izvorima. Uzorkovanje podzemnih voda u dubokom kršu može predstavljati most između ulaznih i izlaznih podataka i tako pridonijeti boljem razumijevanju podzeminih procesa. Duboke jame u kršu kao prirodni fenomen su od izuzetne važnosti jer omogućuju prirodan ulaz i uvid u svijet krških posebnosti. U radu ćemo prikazati vremensku seriju podataka stabilnog izotopnog sastava kiše i vremensku seriju stabilnog izotopnog sastava podzemne vode u kršu. Diskutirat ćemo pitanja koja se nameću u analizi tih vremenskih serija, a na koja bi odgovore dala uzorkovanja u dubokom kršu.

A simple rainwater collector has been developed that allows virtually evaporation-free monthly rain sampling for subsequent water stable isotope analysis. It is designed for collecting composite monthly samples as required for global monitoring of the isotopic composition of precipitation, like the Global Network for Isotopes in Precipitation (GNIP) as operated jointly by the International Atomic Energy Agency (IAEA) and the World Meteorological Organisation (WMO). The new collector has the advantages to minimize necessary staff time for sampling by easy and fast changes of sample bottles, to avoid any need of oil for prevention of evaporation, to be cheap in construction, and to be easily installed and used in remote areas (unattended during on month). Tests performed at the IAEA have proven that water stored in the sampler for nearly one year did not suffer significantly from any evaporation effect. Further comparisons performed at GNIP sampling stations show excellent performance of the new collector with advantages over some conventional precipitation samplers. Slightly more negative delta-values in the new collector than in conventional sampler types could indicate lower evaporation effects.

The precipitation as the input into the water system and its stable isotope composition is a basic part whose knowledge is required for proper use and management of water resources. The geomorphology of Croatia (e.g., high mountains next to the sea) can cause specific local conditions. We have monitored the stable isotopic composition (δ18O and δ2H) of precipitation in more than 25 stations in various locations at different altitudes. For the work reported here, only those data sets are used that span at least one year, altogether 22 stations. The δ18O, δ2H and d-excess altitude effects have been extracted from the measured data base of precipitation isotope ratios. This data base has been used to produce a gridded map of δ18O for Croatia.

Stabilni izotopi kisika i vodika su idealni prirodni obilježivači: kao sastavni dio molekule vode već se nalaze u hidrološkom sustavu i mogu se pouzdano mjeriti u njegovim različitim dijelovima. Proučavajući izotopne signale u oborinama i izvorskoj vodi dolazi se do informacija o zalihama i porijeklu vode u vodonosniku, kao i srednjem vremenu koje je potrebno molekuli vode da prođe put od oborinskog ulaza do izlaza iz podzemlja. Područje prihranjivanja izvora pitke vode koji se koriste za vodoopskrbu grada Rijeke pokriva površinu od oko 400 km2, pripada Dinaridskom kršu, a proteže se i na područje Republike Slovenije. Kako bi se po prvi puta provela karakterizacija izvora pitke vode grada Rijeke stabilnim izotopima Laboratorij za spektroskopiju stabilnih izotopa pokrenuo sustavno praćenje δ18O i δ2H signala u oborinama i izvorskoj vodi na navedenom području. U radu su prikazani odabrani rezultati spomenutog projekta.

The use and protection of the karst aquifers in the border area of Slovenia and Croatia require knowledge of the trans-boundary hydrological conditions. Three out of seven catchment areas between Kvarner and Trieste bay belong to trans-boundary aquifers. Rijeka, the third-largest city in Croatia, is located in this region. The precipitation as input into the water system and its stable isotope composition is a basic part whose knowledge is required for proper use and management of the water resources. The geomorphology of the region (e.g. mountains of 1400 m next to the sea) causes specific local conditions. We have measured the isotopic composition in various locations at different altitudes. For δ18O this ‘altitude effect’ is found to lie between approximately -0.14‰/100m and -0.3‰/100m, depending on the specific location and on the season. Correspondingly, also δD and the d-excess vary.

Fizika predstavlja važnu osnovu specijalističkih medicinskih struka (radiologije, nuklearne medicine, radiološke tehnologije, fizioterapije, itd.), te se iz tih razloga sluša na svim sveučilišnim i stručnim studijima Medicinskog fakulteta u Rijeci. U cilju kvalitetne pripreme studenata za tržište rada na različitim studijskim grupama, a u ovisnosti o budućoj profesiji nastava fizike prilagođena je tako da studenti stječu potrebna specifična znanja i vještine. Kako je nastava fizike prilagođena Stručnom studiju radiološke tehnologije, koja je veza kolegija Fizike i ostalih kolegija na studiju, te kako izgleda detaljni izvedbeni plan prilagođen ovom studijskom programu, na kojem se fizika sluša 120 sati nastave bit će izloženo u ovom radu i ilustrirano primjerima iz nastavne prakse.

U radu donosimo neke od primjera korištenih u izvođenju nastave fizike na Medicinskom fakultetu u Rijeci. Naime, studenti prve godine Stručnog studija Fizioterapije u prvom trimestru, uz temeljne medicinske predmete kao što su Biomehanika i Anatomija, slušaju i predmet Fizika. Naglasak u izvođenju nastave fizike je stavljen na slikovite i stvarne, struci bliske probleme ponašanja bioloških sustava. Na taj način ostvaruje se povezivanje gradiva fizike sa ostalim medicinskim predmetima, te se problemi iz fizike približavaju studentima odnosno pozivu za koji se školuju. Tako se u okviru kinematike izučava gibanje tijela, u dinamici proučava djelovanje mišićne sile, a u statici se rješavaju problemi koštanih poluga. Prilagodbe su učinjene i u drugim studijskim programima. Primjerice, studenti Dentalne medicine u statici se upoznaju sa donjom vilicom kao polugom prvog reda.

Poznavanje vrijednosti δ18O u prostoru ima raznovrsne primjene od hidrologije, geologije do praćenja klimatskih promjena i ekologije. Razvojem GLOBE projekta omogućeno je uzorkovanje na različitim lokacijama u Hrvatskoj, što je uvelike prodonjelo nastanku preliminarne karte stabilnih izotopa Hrvatske. Prvi korak prema razumjevanju prostorne distribucije vrijednosti δ18O u oborinama je povezivanje vrijednosti δ18O sa geografskim parametrima, visinom i širinom. U slijedećem koraku korišten je empirijski model kojeg je razvio Bowen sa suradnicima. Model u kojem su korištene poznate vrijednosti δ18O u oborinama i geografskih parametara pokazuje dobru povezanost tih parametara. Prikazani su preliminarni rezultati dobiveni temeljem empirijskog modela i podataka dobivenih iz GLOBE projekta, te uljnih kišomjera koji su postavljeni najvećim djelom na Kvarnerskom području. Već iz preliminarnih rezultata vide se glavne karakteristike promijene vrijednosti δ18O sa temperaturom (sezonski efekt) i sa visinom (visinski efekt). Cilj korištenja ovakvog modela je mogučnost predviđanja vrijednosti δ18O u prostoru obzirom na to da postoje ograničenja pri uzorkovanju, kako financijska tako i geografska. Kao konačni produkt dobivena je preliminarna karta stabilnih izotopa Hrvatske.

Rezultati monitoringa količina i kakvoće vodnih resursa interesantni su s dva aspekta – na dugoročnoj vremenskoj skali u smislu uočavanja generalnih trendova mogućih promjena, te na kraćoj, unutragodišnjoj skali kao podloga za operativno korištenje i primjerenu zaštitu vodnih zaliha. U radu je utvrđeno da je na duljoj vremenskoj skali prisutan trend opadanja srednjih godišnjih protoka kojima Izvor Rječine i Zvir i prihranjuju tok Rječine. Mogući razlozi postojanja takvog trenda mogu biti promijenjene hidrološke prilike, kao i povećanje zahvaćenih količina voda. Među recentnim promjenama u vodnom režimu navedenih izvorišta za istaknuti je i prisutno povećanje učestalosti i intenziteta zamućenja izvorskih voda. Osim interesa za rezultatima tradicionalnih pokazatelja promjena količina i kakvoće voda, sve složeniji uvjeti na izvorištima zahtijevaju poznavanje i do sada manje korištenih pokazatelja dinamike i zadržavanja podzemnih voda u krškim vodonosnicima. U radu su prikazani prvi rezultati odnedavno pokrenutog projekta istraživanja prihranjivanja riječkih izvora pomoću stabilnih izotopa.

U svijetu je, tijekom hidrogeoloških istraživanja nekog područja, praksa uz klasične hidrogeološke metode istraživanja prostora koristiti hidrokemijske metode, odnosno mjerenja fizikalnih, fizikalno-kemijskih, kemijskih i izotopnih pokazatelja u podzemnim vodama. Slijev izvorišta rijeke Gacke nalazi se na području dinaridskog krša koji je u svjetskim razmjerima poznat kao locus typicus, odnosno klasični krš. Gacka je tipična krška rijeka, ponornica. Ističe se vrlo povoljnim hidrološkim uvjetima. Tijekom godine ne dolazi do znatnih kolebanja količina protoka kroz korito te joj je, za kršku ponornicu, režim ujednačen. S obzirom na to da se u Hrvatskoj 90% vode za potrebe vodoopskrbe dobiva iz zahvata podzemne vode na crpilištima i kaptiranim izvorištima, podzemna voda u kršu je od posebnog značenja jer se gotovo 50% teritorija države nalazi upravo na takvim terenima. Sustav izvora rijeke Gacke po količini i kakvoći može zadovoljiti potrebe vodoopskrbe regije i osigurati značajan ekonomski i socijalni razvoj tog prostora. Zbog očuvanja ovako značajnog prirodnog resursa tijekom 2008. godine, u sklopu međunarodnog projekta, načinjena su hidrokemijska i izotopna istraživanja na sljedećim izvorima rijeke Gacke: Majerovom vrilu, Klancu, Tonkovića vrilu, Knjapovcu, Pećini, Marusinom vrilu, Grabi i Jazu. Na terenu prilikom uzimanja uzoraka izvorskih voda mjereni su ''in situ'' sljedeći fizikalni, fizikalno-kemijski parametri: elektrolitička vodljivost (EC), ukupno otopljene krute tvari (TDS), temperatura vode (T), zasićenost kisikom vode (O2), pH-vrijednost vode i mutnoća vode. Koncentracije fluorida, klorida, nitrata, bromida i sulfata su mjerene metodom ionske kromatografije. Prilikom mjerenja aniona korišten je ionski kromatograf tvrtke LabAlliance, a mjerenja su učinjena u Hidrokemijskom laboratoriju Zavoda za hidrogeologiju i inženjersku geologiju, Hrvatskog geološkog instituta. U istom laboratoriju su izmjerene koncentracije natrija, kalija, magnezija i kalcija metodom atomske adsorbcije pomoću adsorbera tvrtke Perkin Elmer. Sadržaj hidrogenkarbonatnih iona mjeren je titrimetrijskom metodom. Korišteni postupci pripreme i mjerenja uzoraka uobičajeni su u hidrokemiji, a kemikalije korištene za pripremu uzoraka i standardne otopine proizvodi su tvrtke HACH i AccuStandard. Omjeri stabilnih izotopa kisika (18O) i vodika (D) mjereni su u Laboratoriju Zavoda za fiziku, Medicinskog fakulteta u Rijeci. D mjeren je metodom Cr u kontinuiranom toku He u GasBench II koji je spojen s DELTA plus XP masenim spektrometrom tvrtke Finnigan. 18O mjeren je metodom ravnoteže u modu dualnog inleta na masenom spektrometru DELTA plus XP tvrtke Finnigan. Omjeri stabilnih izotopa kisika (18O) i vodika (D) u istraživanju podzemnih voda koriste se za određivanje podrijetla podzemnih voda, područja prihranjivanja, hidrodinamičkih uvjeta, odnosno brzine izmjene voda u pojedinim dijelovima vodonosnika i hidrauličke povezanosti među pojedinim slojevima/vodonosnicima. U prirodi se razlike u omjerima javljaju u vodenom mediju pri faznim prijelazima. Odjeljivanje (frakcioniranje) kod stabilnih izotopa kisika i vodika najviše ovisi o temperaturi faznog prijelaza, tlaku i izotopnom sastavu vode (IAEA/UNESCO, 2001). Tako se, na primjer, prilikom isparavanja iz vodene otopine više izdvajaju lakši izotopi, a sama voda ostaje obogaćena težim izotopima. Također, što je temperatura faznog prijelaza niža, veći je efekt frakcionacije između tekuće i plinovite faze. Rezultat ovisnosti stupnja frakcionacije o temperaturi i tlaku razlika je u omjerima tih izotopa u oborinama (IAEA, 1981.). Tako utvrđene varijacije omjera izotopa u podzemnoj vodi odraz su promjene godišnjih doba, nadmorskih visina područja prihranjivanja, blizine mora, jakih kišnih pljuskova i izotopnih izmjena sa stijenskom masom. Linearnu zavisnost između sadržaja stabilnih izotopa kisika i vodika u većini oborina utvrdio je FRIEDMAN (1953.), a CRAIG (1961.) definirao tu zavisnost formulom: D = 8 18O + 10 i nazvao je GMWL (global meteoric water line). GMWL je izračunata za srednje omjere izotopa vodika i kisika u oborinama cijelog svijeta. Međutim, omjeri stabilnih izotopa vodika i kisika neke regije mogu biti drugačiji od globalnih zbog različitih meteoroloških uvjeta u regiji pa se tada može izračunati LMWL (local meteoric water line). Rezultati mjerenja fizikalnih, fizikalno-kemijskih i kemijskih pokazatelja upućuju da su izvorske vode rijeke Gacke izvrsne kakvoće. Prema svom osnovnom ionskom sastavu izvorske pripadaju CaMg-HCO3 tipu voda što je posljedica otapanja karbonatnih minerala u području prihranjivanja izvora. Izmjereni omjeri stabilnih izotopa kisika (18O) i vodika (D) ukazuju na prihranjivanje izvora padalinama. Isto tako, svi izmjereni hidrokemijski pokazatelja upućuju na grupiranje pojedinih izvorišta (slika 1).

U radu su uspoređene dvije tehnike mjerenja stabilnih izotopa vode: 1) Masena spektrometrija: spektrometrija iona nastalih dekompozicijom H2O na fragmente koji sadrže izotope 16O i 18O, odnosno izotope 1H i 2H, dugo je vremena vodeća tehnika u mjerenju stabilnih izotopa u vode. Tehnika je testirana u studiji koja je uključivala interlaboratorijsku usporedbu. Standardna devijacija delta-vrijednosti je manja od 1 promil za delta2H, te manja od 0, 1 promil za delta18O. 2) Laserska spektroskopija: Nova tehnika u području mjerenja stabilnih izotopa. Mjerenje apsorpcije laserskog svjetla u šupljini koja je ispunjena vodenom parom ispitivanog uzorka. U Laboratoriju za spektrometriju stabilnih izotopa (SILab Rijeka) Zavoda za fiziku Medicinskog fakulteta u Rijeci nalaze se instrumenti za izvođenje mjerenja objema tehnikama što je omogućilo njihovu direktnu usporedbu. Izvedena su mjerenja nepoznatih uzoraka vode kao i mjerenje odgovarajućeg standarda poznate delta-vrijednosti. Rezultati usporedbe vrlo su važni za daljnja istraživanja: poznavanje stabilnih izotopa je od ključne važnosti za meteorološka i klimatološka istraživanja, kao i za istraživanja iz podrčja hidrogeologije i ekologije.

Pb-Zn-Ag deposit Crnac, located within Western Vardar zone, comprises epithermal vein type mineralization and mineralized listwaenites. Fluid inclusion study on carbonates indicate significant drop of temperature and salinities comparing to the pre- and syn-mineralization phase, suggesting involvement of meteoric water within the system.

Water resources in karst areas are very sensitive to pollution. This is of particular significance for Croatia, since about 50% of the country is karst, and the country's water management is a national priority. It is thus of vital interest to have as complete as possible knowledge of all factors which have input into the water system, including precipitation. Besides meteorological data, the isotopic tracers 2H and 18O are important tools to understand and quantify this complex problem.

Comparision of magnetic and laser spectroscopy for stable isotope composition measurement. Analysis of advantages and disadvantages of laser spectroscopy. Presentation of first measurements with Los Gatos LWIA. Report of some technical problems and difficulties in analysis.

Medicinski fakultet u Rijeci u preddiplomskoj i diplomskoj nastavi ima četiri sveučilišna studija i pet stručnih studija. Studijski programi na prvoj godini obuhvaćaju ukupno deset različitih kolegija iz fizike, što iznosi ukupno 520 sati. Od akademske godine 2008./2009. u potpunosti je promijenjen izvedbeni plan nastave. Nastava se organizira u tri trimestra. Ispitni rokovi se održavaju odmah nakon završetka pojedinog trimestra i u mjesecu rujnu. Ustroj i izvedba studija kao i ocjenjivanje i vrednovanje studenata unutar Europskog sustava prijenosa bodova u skladu je s Pravilnikom o studijima koji je na Sveučilištu u Rijeci stupio na snagu 1.07.2008. Analizirali smo i usporedili uspješnost polaganja ispita iz Medicinske fizike i biofizike na studiju medicine za akademsku godinu 2007./2008 i za tekuću 2008./2009. akademsku godinu. Osim toga za navedene akademske godine usporedili smo i uspješnost studenata stomatologije na kolegiju Biofizike. Pokazalo se da postoji statistički značajna razlika u uspješnosti studenata ocjenjenih, na prijašnji, nama poznati način, i onih u skladu s novim Pravilnikom.

Plitvice Lakes, situated in the Dinaric karst, Central Croatia, consist of 16 lakes of different sizes and positioned at different altitudes, connected by waterfalls and streams. The precipitation of calcite from water in the form of tufa and lake sediments is very intensive. The results of delta13C values of dissolved inorganic carbon (DIC) in the Plitvice Lakes water collected at 17 sampling points (springs, tributaries and lakes) in the period 2004-2007, were used for the study of carbon isotope exchange processes between the atmospheric CO2 and the DIC, the equilibrium/non-equilibrium conditions of calcite precipitation (comparison with delta13C of calcite), as well as for the study of the origin of carbon in the lake sediments (autochthon/allochthon). The influence of temperature and amount of precipitation on the delta13CDIC values as well as the influence of some other processes, e.g. primary productivity on the delta13CDIC were also studied. The delta13CDIC values showed a steady increase in the downstream direction, rising from the springs (mean delta13CDIC -12.3‰ ) to the lakes (up to -8.3‰ ). The increase is due to carbon exchange between the DIC and the atmospheric CO2, as well as to photosynthesis process in the lake waters. The more negative delta13CDIC values in springs and tributaries show a higher influence of the CO2 of biogenic origin on the DIC composition. The downstream increase of delta13CDIC correlates with the increase of the delta13C values of calcite in the lake sediments in the same direction, showing that calcite is mainly of autochthonous origin precipitated under equilibrium conditions. Seasonal measurements of delta13CDIC show variations of delta13CDIC in the lake waters influenced by temperature variation, and more stable delta13CDIC values in the spring and tributary waters. The delta13CDIC values of the Plitvice Lakes water measured for the period 2004 -2007 were compared with those for the period 1984 – 2002, and correlated with mean annual air temperature and annual precipitation amount. The most positive delta13CDIC values for majority sampling points were observed in the year 1984 and 2004. These years were characterized by higher air temperature, lower amount of precipitation and lower water outflow. Higher air temperature caused higher water temperature and increase of water evaporation, as well as the acceleration of the process of photosynthesis/primary productivity. The final effect was the increase of delta13CDIC values. The rise of the delta13CDIC values was also reflected in the increase of the delta13C values of the surface lake carbonate, particularly in small lakes. The correlation between the delta13CDIC values and the concentration of the dissolved organic carbon (DOC) in the Plitvice Lakes water showed that in this eco-system photosynthesis is the dominant process in the lakes, with enhanced process of decay of organic material in the spring and tributary waters.

The isotopical composition of recrystallized host limestone corresponds well to the world-wide Phanerozoic marine carbonates. The average delta18O suggests precipitation from the Triassic seawater. Obviously isotopic composition of carbonates was not significantly disturbed by recrystallization. The absence of fluid inclusions within the barren limestone points to recrystallization without involment of neither H2O nor CO2.

Important physico-chemical differences (mobility, rovibrational levels) exist between molecules of different isotopic composition (“ isotopologues” ). This leads to separation effects in their physical and chemical behaviour (“ fractionation” ) which directly influence the isotopic composition of a substance. Evidently, a measurement of this isotopic composition (usually expressed in terms of the so-called “ ä-value” /1/) can therefore tell us something about the processes acting in the system.

Generiranje zvuka i njegova analiza odvajkada je interesirala fizičare, liječnike i obične ljude. Još je od početaka učenja fizike bilo poznato da razumijevanje fizičkih sadržaja ovisi o stupnju uključivanja eksperimenta u nastavu fizike. Veliki broj starih učila iz akustike koja se danas uglavnom ne koriste (Helmholtzovi rezonatori, Koeningov aparat, Chladnijeve ploče, Savartova i Doveova sirena) svjedoče o velikom interesu i trudu tadašnjih profesora fizike za proučavanje i analizu zvuka. U ovom radu biti će dan kratak osvrt na način na koji se analiza zvuka radila nekad i kako se to može vrlo jednostavno napraviti danas uz pomoć računala. Svako periodičko gibanje, pa tako i zvuk, može se prikazati kao superpozicija harmonijskih valova različitih frekvencija. Spektralna (Fourierova ili harmonijska) analiza zvuka je postupak kojim se zvučni val razlaže na njegove sastavne frekvencije. U radu će se prezentirati eksperiment kojim ispitujemo fizikalne karakteristike zvuka, koristeći se pri tome osobnim računalom sa priključenim mikrofonom i katodnim osciloskopom. Spektralnu analizu zvuka izvodi u stvarnom vremenu računalo putem brzih Fourierovih transformacija (eng. FFT – Fast Fourier Transform), a na ekranu se, također u stvarnom vremenu iscrtava graf spektralne analize i očitava se osnovna frekvencija kao i viši harmonici. Koristeći navedenu aparaturu učenicima se mogu objasniti i pokazati osnovne fizikalne karakteristike zvuka kao što su boja, intenzitet i visina. Kvaliteta i boja zvuka ovise o broju i tipu viših harmonika koji se u njemu pojavljuju. Po boji zvuka razlikujemo različite muzičke instrumente, kao i različite ljudske glasove, a to se može vizualizirati opisanim pokusom.

Speleothems are used in climate change studies. In order to reconstruct palaeo-environmental settings on the eastern Adriatic coast during the Late Pleistocene and Holocene, stable isotope analyses of carbonate speleothems, of rain and of drip water in the Modrič Cave were conducted. In this investigation an estimate of the equilibrium isotope condition during the formation of paleothems is required. The cave is situated 120 m from the Adriatic coast in the Southern part of Croatia at an altitude of 32 m a.s.l. Due to its position of the SW slope of the Dinaric mountain range, the Mediterranean climatic influence (humid, hot summers, moderate winters) is dominant. The precipitation is about 1200 mm/a.

In order to reconstruct palaeoenvironmental settings on the eastern Adriatic coast during the Late Pleistocene and Holocene, stable isotope analyses of carbonate speleothems, rain and drip water in Modric Cave were conducted. The cave entrance is located only 120 m from the coast at the altitude of 32 m a.s.l. and due to its position on the SW slope of Dinaric mountain range, Mediterranean climatic influence is dominant. Two stalagmites (22.6 and 20.6 cm long) were collected from the channel with 20-25 m of overlaying bedrock and sparely bush vegetation and terra rossa soil on the surface. According to their overlapped ages, stable isotopes ratios and distinctive hiati, several significant palaeoenvironmental changes could be revealed. Shifts of δ 13C and δ 18O toward more positive values were followed by non-depositional phases. In northern Europe such situation would be interpreted as warming and possible flooding of the cave. On the other hand, in southern regions like in SE Spain, SE Italian Alps (Grotta Savi) and Israel (Soreq Cave), positive shifts indicate cooling and predominance of marine influence within isotope signals. We presume that the latter effect could be recorded in eastern Adriatic speleothems, but it is yet to be confirmed.

Praktikum fizikalnih mjerenja Medicinskog fakulteta Sveučilišta u Rijeci djeluje u sklopu kolegija Medicinska fizika i biofizika prve godine preddiplomskog i diplomskog sveučilišnog studija medicine. Svake godine više od stotinu studenata kolokvira na vježbama u praktikumu. U duhu Bolonjskog procesa, neposredno po završetku vježbi, zadnje dvije akademske godine proveli smo anketu među studentima. Između ostaloga, želja nam je bila saznati kakva su njihova iskustva s obzirom na način izvođenja nastave fizike s kojim su se susretali prije upisa na fakultet, jesu li već upoznati s eksperimentalnim radom u fizici, te koje je njihovo mišljenje o praktikumu i fizici

Students interested in the GLOBE program collect and determine amounts of daily precipitation, measure air temperature and send monthly averaged water samples to the Stable Isotope Laboratory (SILab)at Rijeka University. At the SILab, samples are analysed for their conductivity, pH, dissolved oxygen, salinity and isotopic composition in regards to delta2H and delta18O. The delta-values are determined in a Thermo-Finnigan DeltaplusXP mass spectrometer. The first results of this projects already demonstarte the complexity of the meteorological situation in the country, it is appropriate to briefly look at the location of the country and corresponding implications.

U cilju stvaranja jedinstvenog europskog visokoškolskog sustava Hrvatska je deklaraciju pod nazivom Europski prostor visokog obrazovanja, danas popularno nazvanu Bolonjska deklaraciju, potpisala 2001. godine na ministarskoj konferenciji u Pragu i time preuzela obvezu prilagodbe visokog školstva njezinim zahtjevima. 2006/2007. akademsku godinu upisala je druga generacija studenata po reformiranim ili posve novim studijskim programima. U ovom radu, a na osnovi stečenih iskustava na stručnim studijima Medicinskog fakulteta u Rijeci, ukazali bi na potrebu prilagodbe nastavnih programa srednjih strukovnih škola programima stručnih studija po Bolonjskom procesu.

The water management in Croatia is a national priority since about 50% of the country consists of karst. It is thus of vital interest to have a complete as possible knowledge of all related factors, including the precipitation as the input into the water system. Besides meteorological data, isotopic tracers are important tools to understand and quantify this complex problem. Very little information exists, however, about the isotopic composition of precipitation in Croatia. Therefore, we propose to collect precipitation through the GLOBE program in order to establish an atlas of the isotopic composition of precipitation for as wide an area of Croatia as possible. GLOBE (Global Learning and Observations to Benefit the Environment) is a worldwide primary and secondary school-based science and education program. In Croatia, about 100 schools are involved in GLOBE, and about 25 contribute in this nationwide collection of precipitation. These samples are then sent to and analysed in the Stable Isotope Laboratory at Rijeka University (SILab Rijeka). First results will be shown at the Conference.

Na Sveučilištu u Rijeci osnovan je prvi hrvatski laboratorij za masenu spektroskopiju stabilnih izotopa s ciljem istraživanja krškog područja te proučavanja procesa u hidrološkim, hidrogeološkim i meteorološkim ciklusima. U radu su izneseni preliminarni rezultati mjerenja δ 18O u vodi za tri izvora rijeke Gacke. Interpretaciju rezultata mjerenja upotpunjuju podaci iz Državnog hidrometeorološkog zavoda.

Na savjetovanju ravnatelja i nastavnika o provedbi programa GLOBE predstavljena je ideja o uključivanju novih mjerenja u laboratoriju za stabilne izotope u Rijeci. Zadatak učenika bi bio da po protokolu GLOBE programa rade meterološka opažanja uz dodatak sakupljanja oborinske vode. Sakupljenu vodu potrebno je nakon mjesec dana poslati na adresu laboratorija. Potreban materijal za uzorkovanje biti će dostavljen školama.

A large fraction of Croatia (nearly 50%) consists of Karst, and the study of related hydrogeological problems are high on the country’ s priority list. Therefore, Croatia’ s first laboratory for stable isotope mass spectrometry has been set up at Rijeka University. It features a Delta+XP , fitted with a Gas Bench (incl. a 96-position autosampler, generally used for δ 18O analysis in water and carbonates) and a Dual Inlet. Addition of an Equilibration Unit is planned for high-precision δ D measurement. Several home standards (ca. 40 l each) covering a δ 18O range between – 1.6 and -26, 4 have been calibrated against standardized samples. First δ 18O measurements serve as examples for the application of IRMS data to determine the dominant recharge areas of Gacka river and Vrana lake. We gratefully acknowledge supported by the MZOS in project 0062011 and by the IAEA in project CRO/8/006.

The aim of our work was to point out some issues regarding physics education in secondary professional medical schools in Croatia and to initiate the development and harmonization of new curricula in secondary professional medical schools with corresponding physics courses taught in professional studies at the higher level.

Croatia signed the Declaration of the European Higher Area, known as the Bologna Declaration, at the ministerial conference in Prague in 2001, taking the obligation to adopt the Croatian system or higher education of European standards. In the academic year 2006/2007, the second generation of students enrolled in the reformed or completely new study programs. According to the experience obtained from professional studies at the Faculty of Medicine Rijeka, the author point to the need of the adoption of secondary professional schools curricula to the programs of professional studies based on the Bologna process.

The main springs of the Gacka river drainage area (Majerovo vrelo, Tonković vrelo and Pećina) have been studied by means of stable (18O) and radioactive (3H) isotope measurement. This area is situated in the Dinaric karst that comprises very important groundwater storage reservoirs. Since karst is characterized by high permeability, porosity and crevices in which water moves in complex subterranean networks, it is very sensitive to any kind of pollution. Gacka river is located in the Lika region at an altitude of about 400 m above sea level. Although its climatic conditions are mainly continental, the situation is complicated by the occasional influence of maritime Adriatic air masses. Water samples from the three springs (continuous sampling, some other springs occasionally) as well as precipitation were collected monthly in the period 2005-2006. Tritium measurements have been performed at the Laboratory for Measurements of Low-level Radioactivity of the Rudjer Bosković Institute, Zagreb, while stable isotope δ 18O measurements were carried out at the new stable isotope facility (Environmental Physics Laboratory) at Rijeka University. In the time period under study, δ 18O in the Gacka precipitation is (– 8.7 ± 2.1) ‰ with seasonal fluctuations typical for continental stations in the area . δ 18O fluctuations in the spring waters are much smaller, indicating well-mixed waters. The three springs have fairly different δ 18O -values although they are located at approximately the same altitude. This indicates that their catchments lie at different altitudes. The spring water temperatures and flow rates show no direct correlation with the ambient temperature and the amount of precipitation. Large precipitation amounts in August and December 2005 have apparently no immediate effect on the spring δ 18O - values. A weak seasonal variation again indicates a delayed response and good mixing. The seasonal tritium distribution for the precipitation in the Gacka area is well correlated with that in Zagreb, the closest GNIP continental station. All three main springs show similar mean tritium concentrations, but much smaller seasonal variations than precipitation, indicating a short mean residence time and good mixing of infiltrated and ground water.

The results of the questionnaire presented at the 8th Croatian Symposium on Teaching in Physics showed that the most popular form of physics teaching, within a population sample of first year medical students, is laboratory class. The work presented at the poster is a further evaluation of the above mentioned questionnaire and tries to distinguish the lab experiments that non-physics graduates (medical students) like, the ones they find difficult, the reasons for that, and their view of the purpose of laboratory class in physics at the School of Medicine in the first place.

Hydrogeological investigations using hydrochemical and isotopic methods have been performed to determine the sanitary protection areas of springs in the drainage area of the Vransko Polje near Biograd (North Dalmatia) and main springs in the drainage area of the Gacka River (Lika region). The two investigated areas are situated in the Dinaric Karst that comprises very important groundwater storage reservoirs in Croatia. The chemical composition of spring waters from the Gacka River recharge area shows low concentration of total dissolved salts. Low concentrations of nitrates, amonium and phosphates indicate non-polluted ground waters in this area. Hydrochemical composition of spring waters in the Vransko Polje recharge area shows seasonal vegetation and hydrological variations (Cl-, SO42-, NO3-) closely related with the sea water influence and anthropogenic activities. The sewage waters from settlements and agriculture activity affect the quality of spring waters mainly after a dry season when the precipitation washes out soil and the unsaturated zone of karst aquifers. The mean 3H activity in all main springs in the Gacka River area is similar to that of precipitation, while in the springs of Vransko Polje the mean 3H activity is lower if compared with precipitation due to sea water infiltration. There is no seasonal fluctuation of 3H activity in all springs indicating fast circulation and good mixing of precipitation and ground waters. Correlation between d2H and d18O in both areas showed the values close to the MWL but with distinguish differences with lower values for Gacka river springs (higher altitude, continental climate) and higher for Vransko Polje springs (Mediterranean climate, low altitude). Also the stable isotope data show only weak seasonal variations, again indicating a fairly short mean residence time and good ground water homogenization. Stable as well as radioactive isotope data indicate that both areas are very sensitive to any kind of pollution and the response to the pollution will be very fast. The results of this project will be used in definition of protection measures for the water supply for the recharge areas of Gacka River and Vransko polje springs and establishment of close cooperation between hydrogeolgists from Hrvatske vode, Environmental Geochemical Laboratory and institutions that perform the isotope analyses such as Rudjer Bošković Institute, Zagreb and Stable Isotope Laboratory, Rijeka.

Toksični spojevi koji se pušenjem cigareta unose u organizam uzrokom su oboljenja među kojima je i ateroskleroza. Tu bolest krvožilnog sustava karakterizira nakupljanje ateroma uz stijenke arterija što dovodi do smanjenja njihove elastičnosti. Fizikalno gledajući krvotok predstavlja složen problem iz područja mehanike fluida. U pokusu se uspoređuje volumni protok tekućine, u danom vremenu, kroz cijev elastičnih i cijev krutih stijenki. Cijevi predstavljaju pojednostavljen model zdrave arterije i arterije čije su stijenke izgubile elastičnost. Pokus potvrđuje fiziološka promatranja da je elastičnost krvnih žila jedan od najvažnijih faktora za normalan krvotok.

Bolonjska deklaracija predstavlja ključni dokument i prekretnicu u razvoju visokog obrazovanja u Europi. Zemlje potpisnice među kojima je i Hrvatska obvezale su se pristupiti zajedničkoj reformi strukture sustava visokog obrazovanja. Cilj je stvaranje europskog prostora za visoko obrazovanje u kojemu će stupnjevi obrazovanja biti međusobno usporedivi. To će se postići uvođenjem dodiplomskog i poslijediplomskog studija u svim zemljama, s tim da se prvi stupnjevi stječu nakon najmanje 3 godine. Bolonjska deklaracija nas obvezuje da i mi uskladimo svoje programe i stvorimo nove curriculume svih studija, pa tako i fizike. U radu će biti prikazan probni model SR Njemačke konsekutivnog obrazovanja nastavnika sa stupnjevima "Bachelor" i "Master", koji je pokušaj prilagodbe na Bolonjsku deklaraciju.