Ines Krajcar Bronić

Ruđer Bošković Institute | RBI · Division of Experimental Physics

For more than 40 years, isotope research of environmental compartments has been conducted at the Plitvice Lakes. Though it started with initial idea to radiocarbon date tufa, the emerged problems regarding tufa dating eventually led to isotope research of water and carbon cycles, dating of tufa and sediments by other isotopes, using sediment and tu...

Recently developed direct LSC method for the biogenic fraction determination in biodiesel samples was evaluated. Intercomparison samples had the unknown composition of biomaterials/fossil fuels and a broad range of quench levels. Reliable results were obtained with the direct two-step LSC method for the samples with a quench level of roughly 50 cha...

Carbonization, i.e., turning organic sample to carbon, was validated for the benzene synthesis for the radiocarbon liquid scintillation measurement. Tests of sample preparation by combustion, carbonization followed by combustion and carbonization followed by a direct reaction with lithium were performed. Wood and charcoal samples were good for carb...

The Athos peninsula is located in Northern Greece and constitutes one of the last unexplored areas of Greece regarding hydrogeological conditions. This study is focused on the Hydrosystem of the Holy Monastery of Simonos Petra with the aim of determining the hydrochemical regime of the fracture zone aquifer.

In this paper we present dating of archaeological samples from Croatia only performed since our last reports (Obelić et al. 2011; Horvatinčić et al. 2012). Liquid scintillation radiometric measurement technique with benzene synthesis (LSC-B) and accelerator mass spectrometry (AMS) technique were applied.

Air temperature and precipitation data (1976–2021), stable isotope composition (δ18O, δ2H) data, and deuterium excess (1980–2021) data were analyzed using principal component analysis (PCA), Fourier analysis (FA), and wavelet analysis (WA). The PCA represented each month by a single dot in the diagram, and month 1 and month 7 were clearly distingui...

Determination of fraction of biogenic component in liquid fuels by a direct radiocarbon measurement in liquid scintillation counter (direct-LSC method) has been validated by participation in the international intercomparison exercise. All the results for samples with the standard quench parameter SQP(E) value above ≈ 650 were accepted. Highly quenc...

Past environments of the Earth's surface may be deciphered and modelled using stable isotopes along with mineralogical, sedimentological, biological, palaeontological, chemical and climatological methodologies. This volume is devoted to studies investigating the distribution of stable isotopes in precipitation and groundwaters and their interaction...

Tufa is a fresh-water surface calcium carbonate deposit precipitated at or near ambient temperature, and commonly contains the remains of macro- and microphytes. Many Holocene tufas are found along the Zrmanja River, Dalmatian karst, Croatia. In this work we present radiocarbon dating results of older tufa that was found for the first time at the Z...

Karst environments preserve some of the best archives of past climate, vegetation, hydrology, anthropogenic impact, and landscape evolution providing that a reliable chronology can be established. Here we present an example of the system of the Plitvice Lakes (Dinaric karst, Croatia), which is characterized by intensive tufa and lake sediment forma...

Dušan Srdoč was born on January 11, 1929 in Rijeka, Croatia. He graduated at the Technical Faculty of the University of Zagreb in 1953 and was employed at the Ruđer Bošković Institute (RBI) in Zagreb, Croatia, where he founded Laboratory for development and production of detectors of ionizing radiation. He defended his Ph.D. dissertation in 1965 wi...

It has been expected that the solar cycle may have an influence on the production rate of cosmogenic tritium. However, prevailing anthropogenic bomb tritium in precipitation in the second half of the 20th century prevented such studies. We analyzed long-term data (1976–2020) of tritium activity concentration in precipitation at Zagreb, Croatia, by...

The availability and quality of freshwater currently represent one of the great issues for mankind [...]

An underwater survey was conducted in September of 2020 on several locations in Kaštela Bay, mainly around the area of Pantan near Trogir, with the aim of assessing the potential of these locations for more detailed investigations. The limited survey gave positive results, as the collected prehistoric and Roman material pointed to a great potential...

Radiocarbon activity (a 14 C) and 13 C composition (δ 13 C) were measured in hygrophyte and mesophyte (land) mosses collected in the natural habitat of the Plitvice Lakes and along the Zrmanja and Krupa Rivers (typical continental and Mediterranean climates, respectively), Croatia. a 14 C and δ 13 C values of mosses, of atmospheric CO2 and dissolve...

Tritium (3H) as a constituent of the water molecule is an important natural tracer in hydrological sciences. The anthropogenic tritium introduced into the atmosphere unintentionally became an excellent tracer of processes on a time scale of up to 100 years. A prerequisite for tritium applications is to know the distribution of tritium activity in p...

The application of tritium, 2H, and 18O in the characterization of the precipitation, groundwater, and surface and lake water of the Plitvice Lakes (PL), Croatia, over the 1979–2019 period is presented. An increase in the mean annual air temperature of 0.06 °C/year and in the annual precipitation amount of 10 mm/year is observed. The good correlati...

Carbon isotope composition of dissolved inorganic carbon (DIC) was studied at springs, lakes and tributaries of the Plitvice Lakes. The Plitvice Lakes are a unique and complex karst lakes system consisting of 16 flow-through lakes connected by waterfalls and streams and characterized by intense calcium carbonate precipitation in the form of tufa an...

Abstract. Tritium (³H) as a constituent of the water molecule is an important natural tracer in hydrological sciences. The anthropogenic tritium introduced into the atmosphere became unintentionally an excellent tracer of processes on the time scale of up to a 100 years. A prerequisite for tritium applications is to know the distribution...

The isotope composition of precipitation has been monitored in monthly precipitation at Zagreb, Croatia, since 1976. Here, we present a statistical analysis of available long-term isotope data (3H activity concentration, 2H, 18O, and deuterium excess) and compare them to basic meteorological data. The aim was to see whether isotope composition re...

The Aqueduct is one of the city landmarks of Skopje, Republic of North Macedonia. It was part of a water-supply system, with a total original length of about 10 km, while its surface remains are about 385 m long. The age of the Aqueduct is not known—several hypotheses place it to periods between the 6th and 16th centuries. Six mortar samples from d...

Isotopes of hydrogen (3H, 2H) and oxygen (18O) are perfect candidates for groundwater tracers. A survey of isotopic composition of 34 groundwater samples and one Lake from Vojvodina region (Serbia) is presented here. Tritium activity concentration and stable isotope composition (δ2H, δ18O), as well as deuterium excess, were determined. The groundwa...

Summary Nikolina Topić, Ines Krajcar Bronić, Andreja Sironić RESULTS OF ARCHAEOLOGICAL SURVEILLANCE AND DATING OF WOODEN FOUNDATION BEAMS FROM THE ATRIUM OF THE RECTOR’S PALACE IN DUBROVNIK The Rector’s Palace in Dubrovnik is one of the most prominent Gothic-Renaissance buildings on the Adriatic coast. It was transformed from a defensive buildin...

This paper explores the possibility of a direct measurement of ¹⁴C activity concentration in wastewater without chemical pretreatment of samples, which would provide the advantages such as rapidity, low-cost, and simplicity of radioanalysis that is desirable in the case of nuclear emergencies. A method via Liquid Scintillation Counting (LSC) techni...

The Conference is a conclusion of the five-year-long conservation-restoration project of the Croatian Conservation Institute and the Ministry of Culture of the Republic of Croatia, presented to the public in an international multimedia exhibition, too. Adding to the contributions of the conservator and principal researcher, Žana Matulić Bilač (Croa...

Liquid scintillation counting (LSC) is the most commonly used technique for measurement of tritium activity concentration in aqueous samples. This chapter offers an overview of the advances made in the measurement methods and applications of different LSC methods for tritium determination, as well as developments and optimization of said methods. F...

Tritium is a radioactive isotope of hydrogen with a physical half-life of 4500±8 days that behaves like stable hydrogen and is usually found attached to molecules replacing hydrogen. This radioactive isotope is directly incorporated into the water molecule (H3HO or HTO) and therefore it can be detected in all waters. This radionuclide occurs in nat...

A method of direct measurement of 14 C activity concentration via liquid scintillation counting (LSC) is recognized as good and fast methodfor determination of biogenic component in liquid fuels. Two laboratories that used this 14 C technique participated in this survey: Laboratory from University of Novi Sad (UNS), Serbia and Laboratory from Ruđer...

The first monitoring of isotope composition of precipitation in Slovenia was performed in the period 1972–1975 in the frame of Ljubljanica River drainage basin investigations while regular and systematic monitoring began in 1981 in Ljubljana. The Slovenian Network of Isotopes in Precipitation (SLONIP) monitoring network has been extended during the...

Determination of biogenic fraction in liquid fuels by direct measurement of the 14C activity concentration via liquid scintillation counting (LSC) technique has been adopted in few laboratories worldwide. This method is regarded as fast, simple, accurate and sensitive determination procedure for the mass assessment of biogenic fraction in biofuels...

Six sediment cores, the top 30–40 cm, from two lakes of different sizes, Lake Prošće and Lake Kaluđerovac, situated in the karst region of the Plitvice Lakes system, Croatia, were studied by mineralogical and structural, C/N and total organic carbon (TOC) and isotopic analyses (a¹⁴C and δ¹³C of carbonate and organic fractions). The study of the two...

The fraction of biogenic component within various types of materials that can be used as fuels for energy production and transport can be determined by measuring their 14C activity. The method is based on different 14C signatures of the biogenic and the fossil components: while the biogenic component reflects the modern atmospheric 14C activity, no...

The stable isotopic composition of oxygen and hydrogen (δ18O and δ2H) and the tritium activity (A) were monitored in precipitation at synoptic station Portorož (Slovenia) during the period 2007–2010. Monthly and yearly isotope variations are discussed and compared with those observed over the period 2001–2006 and with the basic meteorological param...

The stable isotopic composition of hydrogen and oxygen (δ2H and δ18O) and the tritium activity (A) were monitored in monthly collected precipitation at Ljubljana (Reaktor) during the period 2007–2010. Monthly and yearly isotope variations are discussed and compared with those observed over the period 1981–2006 and with the basic meteorological para...

The analyses of radioactive isotopes 14C, 137Cs and 210Pb, and stable isotope 13C were performed in the sediment cores, top 40 cm, taken in 2011 from karst lakes Prošće and Kozjak in the Plitvice Lakes National Park, central Croatia. Frozen sediment cores were cut into 1 cm thick layers and dried. 14C activity in both carbonate and organic fraction...

Partial pressure of CO2 (pCO2) and its isotopic composition (δ13CairCO2) were measured in Postojnska jama, Slovenia, at 10 locations inside the cave and outside the cave during a one-year period. At all interior locations the pCO2 was higher and δ13CairCO2 lower than in the outside atmosphere. Strong seasonal fluctuations in both parameters were ob...

Postojna Cave (Slovenia) is one of the most famous karst caves in South Eastern Europe. Drip water is one of the factors that determines cave interior. During 2010 and 2011 monitoring of drip water in Postojna Cave was performed at 9 locations within the Cave. Drip rate was measured and the isotopic composition (delta 18O) of drip water was determi...

A new line for preparation of the graphite samples for 14C dating by Accelerator Mass Spectrometry (AMS) in the Zagreb Radiocarbon Laboratory has been validated by preparing graphite from various materials distributed within the Fifth International Radiocarbon Intercomparison (VIRI) study. 14C activity of prepared graphite was measured at the SUERC...

OD ZRAČENJA s međunarodnim sudjelovanjem Krk, otok Krk, 10. – 12. travnja 2013. U gradu Krku na otoku Krku od 10. do 12. travnja 2013. održan je Deveti simpozij Hrvatskog društva za zaštitu od zračenja (HDZZ) s međunarodnim sudjelovanjem. Skup je organizirao HDZZ uz pomoć suorganizatora Instituta Ruđer Bošković, Instituta za medicinska istraživanja...

This paper presents dating results of geological (speleothems, tufa, soil, and sediment), biological (mollusks and botanical), as well as hydrogeological samples from Croatia, Slovenia, Bosnia and Herzegovina, Turkey, and China. Included are results of samples measured by gas proportional counting (GPC) in the Zagreb lab until abandonment of this t...

δ(13)C values of various plants (apples, wheat, and maize) collected in the vicinity of the Krško Nuclear Power Plant (Slovenia) during 2008 and 2009 were determined. By measuring dried samples and their carbonized counterparts we showed that no significant isotopic fractionation occurs during the carbonization phase of the sample preparation proce...

Recent archeaological excavations of the church of St. Stepehen in Pustijerna, Dubrovnik, Croatia, undertaken in 2011/2012, comprised all cultural layers inside the church area and a segment of church cemetary underneath the church courtyard resulting in some important new findings. Several phases of the church development were documented, from the...

This paper presents dating results of geological (speleothems, tufa, soil, and sediment), biological (mollusks and botanical), as well as hydrogeological samples from Croatia, Slovenia, Bosnia and Herzegovina, Turkey, and China. Included arc results of samples measured by gas proportional counting (GPC) in the Zagreb lab until abandonment of this t...

The stable isotopic composition of hydrogen and oxygen (d2H and d18O) and tritium activity (3H) have been monitored in monthly precipitation at Portorož airport meteorological station since October 2000. Here we present a complete set of numerical data and a statistical analysis for the period 2000–2006. Seasonal variations of d2H and d18O were obs...

Radioactive isotope tritium (3H) and stable isotopes of hydrogen (2H/1H) and oxygen (18O/16O) were measured during 2010 in the Sava River, precipitation and groundwater at 3 monitoring wells and 1 production well of the Petruševec aquifer, close to the Sava River in the Zagreb area. Significant increase of 3H activity in the Sava River was observed...

In this paper, we present dating of archaeological samples performed since our last report (Obelić et al. 2002). Included are results of samples measured by the gas proportional counting (GPC) method until the abandonment of this technique in 2007, as well as results of several series measured by both GPC and liquid scintillation counting (LSC) met...

After introducing the liquid scintillation counting (LSC) method and graphite target preparation for accelerator mass spectrometry (AMS) measurements in the Zagreb Radiocarbon Laboratory, the existing database software designed only for gas proportional counting (GPC) (using a DOS operating system) could not satisfy the requirements for parallel co...

Radiocarbon is a cosmogenic radioisotope equally distributed throughout the troposphere and biosphere. This fact enables its most common application—radiocarbon dating. Natural equilibrium of radiocarbon has been disturbed by diverse anthropogenic activities during the last ∼150 years, enabling also the use of 14C in various environmental applicati...

Modrič Cave is a shallow horizontal cave situated in the middle of the eastern Adriatic coast (Croatia). The cave entrance is located 120 m from the coast at an altitude of 32 m above sea level, and due to its position on the SW slope of the Dinaridic mountain range, a Mediterranean climatic influence is dominant. Due to the stable environmental co...

The new line for preparation of graphite samples for 14C dating by AMS has been constructed in the Zagreb Radiocarbon Laboratory. The performance of the rig and sample preparation procedure has been validated by preparing graphites from various reference materials of known 14C activity. The yield of the graphitization was good and the measured frac...

ENVIRONMENTAL 14C ACTIVITY: THE ATMOSPHERE AND THE BIOSPHERE The natural equilibrium of 14C activity in atmospheric CO2 and in the biosphere has been disturbed globally by various anthropogenic activities. Intensive atmospheric thermonuclear bomb tests in the mid 20th century doubled the natural 14C activity in the atmosphere. Since the bomb test b...

Croatian Radiation Protection Association (CRPA, www.hdzz.hr/) was founded in 1979 and in 1992 became a regular member of the International Radiation Protection Association (IRPA). The 30 th anniversary of CRPA is an opportunity to review the work of the society and to point out the main goals for the future. Seven national symposia of CRPA with in...

Monitoring 14 C activity in the atmospheric CO 2 and in biological samples (fruits and vegetables) in the close vicinity of the NPPK was performed regularly since 2006 to estimate the possible influence of the plant on environmental 14 C levels and the possible contribution to the effective dose of local population through food chain. Mean values o...

Measurement of low-level tritium activities in natural/non-polluted waters, e.g. in precipitation and groundwater, requires special techniques for water pretreatment and detection of low-level radioactivity. Two methods for low-level tritium measurement have been developed in Zagreb Radiocarbon and Tritium Laboratory: gas proportional counting (GPC...

Determination of the initial 14 C activity (a 0) of the spelean calcite in the Modrič Cave, Croatia, was performed by measurement of 14 C activity of carbonate collected on a nylon sheet in the period 1999-2007 ((106.2 ± 1.1) pMC) and comparing it with the mean atmospheric 14 C activity of the period covering calcite formation. Due to the damping e...

Traditional investigations of groundwater resources in karstic areas usually utilize geological, hydrogeological and water quality data in order to establish a conceptual model for the investigated aquifer. Sometimes, such data are not always fully available. In order to overcome these obstacles the combined hydrogeological and geochemical approach...

Measurement of (14)C activity in various types of samples has been performed in the Zagreb Radiocarbon Laboratory since 1968 by proportional counting technique and since 2001 by liquid scintillation counting (LSC) technique by using LSC Quantulus 1220. We either prepare benzene or absorb CO(2) obtained from the sample in a scintillation cocktail. V...

The stable isotopic composition of hydrogen and oxygen (δ2H and δ18O) and tritium activity (3H) are monitored in monthly precipitation at Ljubljana since 1981. Here we present complete set of numerical data and the statistical analysis for period 1981–2006. Seasonal variations of δ2H and δ18O are observed and are typical for continental stations of...

Five short cores (top 40-45 cm of sediment) from 4 lakes of the Plitvice Lakes system (Croatia) were measured for 210Pb, 137Cs, a14C, δ13C, and δ18O in order to study the influence of environmental changes on the sediment system in small and large lakes. Sediment chronology based on the constant flux (CF) 210Pb model was the most reliable. Lake sed...

We present the first results of a study of the Gacka River spring area, an important Croatian drinking water resource. Stable isotope data (obtained at the Stable Isotope Laboratory SILab in Rijeka) are used in combination with hydrological and meteorological data. The delta18O values give information on the mean catchment altitudes of the three ma...

Heavy ions, such as carbon and oxygen ions, are classified as high-LET radiations, and produce a characteristic dose-depth distribution different from that of low-LET radiations such as γ-rays, xrays and electrons. Heavy ions lose less energy at the entrance to an irradiated biological system up to some depth than the low-LET radiations, while they...

The famous single-arch stone bridge over the Neretva River in Mostar, Bosnia and Herzegovina, was built in 1557–1566 by the order of Ottoman Sultan Süleyman the Magnificent. During the reconstruction of the Old Bridge, which was destroyed during the war in 1993, remnants of 2 older wooden bridges were found at the same location. Six wood and 2 char...

In Northern Croatia, more than hundred settlements are known from the period of the Starčevo culture, the first Neolithic period in south-east (SE) Europe. Here we present the 14C dating of nine charcoal samples from the Neolithic settlement Galovo in Slavonski Brod. According to archaeological findings, it belongs to the early phase (Linear A) of...

The results of radiocarbon dating of several Late Neolithic archaeological sites in Slavonia, eastern Croatia, are presented. According to the archaeological findings, the sites belong to the Sopot culture. Stages I-B, II-A, II-B, and III were identified at the eponym site Sopot near Vinkovci, stages I-B and II at the site Dubovo-Košno near éupanja...