Geochemical and mineralogical characteristics of soil from the Petruševec well field area : master’s thesis

Predmet ovog diplomskog rada su uzorci tla prikupljeni na području vodocrpilišta Petruševec. Cilj je bio odrediti geokemijske i mineraloške karakteristike tla u svrhu karakterizacije mogućeg onečišćenja podzemne vode s potencijalno toksičnim metalima. Uzorkovanje tla je izvršeno u drugoj zoni sanitarne zaštite vodocrpilišta Petruševec. Nakon provedenog terenskog istraživanja, uzorci tla su u proljeće, ljeto i jesen 2018. godine analizirani u laboratoriju na Zavodu za mineralogiju, petrologiju i mineralne sirovine, Rudarsko-geološko-naftnog fakulteta u Zagrebu. Atomskom apsorpcijskom spektrometrijom (AAS) izvršeno je mjerenje koncentracije Zn, Mn, Cu, Cr, Ni, Fe, Pb i Cd. Izuzev povišenih koncentracija Fe i Mn utvrđene su značajne koncentracije Cr i Ni. Ni u analiziranim uzorcima višestruko prelazi zakonom propisane vrijednosti pri čemu je najveća izmjerena koncentracija na dubini od 190 cm. Koncentracije kroma slično je raspoređena po profilu tla, a uočeno je kako su koncentracije nikla i kroma veće na dubini od 70 do 190 cm s najvećim vrijednostima na 190 cm dubine. Izvor nikla i kroma je moguće antropogenog podrijetla vezan za aerodepoziciju s obližnje zračne luke, otpad koji odložen u blizini područja uzorkovanja ili prirodnog podrijetla iz stijena bogatih ovim metalima.The subject of this thesis are soil samples collected at the Petruševec well field area. The aim of this research was to determine geochemical and mineralogical characteristics of soil to determine a possible groundwater contamination with toxic metals. Soil sampling took place in the second zone of sanitary protection of the Petruševec water well field. After fieldwork, soil samples were analyzed during spring, summer and autumn of 2018 at the Department of Mineralogy, Petrology and Mineral Resources at the Faculty of Mining, Geology and Petroleum Engineering, University of Zagreb. Measurement of concentration of Zn, Mn, Cu, Cr, Ni, Fe, Pb and Cd was conducted using atomic absorption spectroscopy (AAS). Except high concentrations of Fe and Mn, significant concentrations of Cr and Ni were also detected. In analyzed samples Ni exceeds values provided by the law multiple times and highest measured concentration was determined at depth of 190 cm. Concentrations of chromium are similarly distributed over the soil profile, and it can be noticed that chromium and nickel concentrations are higher in the depth range from 70 to 190 cm while the highest values were recorded at the depth of 190 cm. The source of chromium and nickel could be anthropogenic, related to aero deposition from the airport, from waste near sampling area, or natural from rocks rich with these metals

Estimation of precipitation fraction in the soil water of the Hillslope Vineyard using stable isotopes of water

This paper presents research related to the estimation of the precipitation fraction in the soil water of a sloped vineyard at the SUPREHILL Critical Zone Observatory (CZO) in Zagreb, Croatia. Numerous investigations have shown that exploration of hillslope soils can be very challenging due to the existence of heterogeneity and different soil properties, as well as due to anthropogenically induced processes, which can affect precipitation infiltration and soil water flow. Within this research, physicochemical soil properties, soil water content (SWC), and isotopic composition of soil water and precipitation

La Patrie : journal quotidien, politique, commercial et littéraire

20 octobre 18631863/10/20 (A23)

Implementacija Ti(III) redukcijske metode u svrhu određivanja izotopnog sastava dušika (δ15N) i kisika (δ18O) iz nitrata

Pollution of surface and groundwater by nitrate (NO3–) is one of the most serious environmental problems worldwide. The crucial isotopes for the sources and dynamics of nitrogen (N) in the aquatic environment are the nitrogen and oxygen isotope data of NO3-. The stable isotope of nitrogen (δ15N) in dissolved nitrate has been most commonly used to estimate NO3- sources in groundwater. However, measurement of the stable nitrogen isotope alone does not provide a definitive determination of NO3– origin, so the stable oxygen isotope (δ18O) must be used, i.e., a dual isotope approach. The analysis of NO3- for both δ15N and δ18O has been made possible by the development of various laboratory methods for sample preparation, each with its own advantages and disadvantages. Current methods such as the cadmium reduction method (Azide method) or the bacterial denitrification method require toxic chemicals or anaerobic bacterial cultures for NO3- reduction to N2O gas. In 2019, a new sample preparation method was developed (ALTABET et al., 2019), which is a simple one-step conversion method that utilizes Titanium( III) chloride reagent to reduce NO3– to N2O within septum sample vials: 2NO3 – (aq) + 8Ti+3 + 10H+ → N2O(g) +8Ti+4 + 5H2O A single sample preparation takes only a few minutes, followed by a 24-h reaction that generates N2O headspace gas for δ15N and δ18O analysis by IRMS or laser spectrometer. Briefly, Ti(III) chloride is preconditioned with zinc metal powder about 30 minutes before sample preparation to ensure efficiency by removing Ti(IV). The volume ratio of sample to reagent for groundwater samples is 10:1, 20:1, or 40:1. We found that higher amounts of Ti(III) reagent (10:1 and 20:1 ratios) gave slightly more accurate δ18O values. The δ15N values were most inaccurate at ratios of 10:1 and 40:1, but were more accurate at a 20:1 ratio of sample to reagent. Therefore, a 20:1 ratio is considered practical for further measurements. To ensure consistent N2O yields and 15N and 18O results, the N concentrations in each vial must be identical for all samples, laboratory controls, and standards. This is achieved by adding an appropriate volume of sample, degassed deionized water, 10% hydrochloric acid, and the preconditioned Ti(III) chloride reagent. The δ15N and δ18O isotope analyses were performed using the Isotopic N2O Laser Analyzer (GLA451-N2OI3), which was acquired as part of the CRO7002 project “Using Nitrogen and Oxygen Stable Isotopes in the Determination of Nitrate Origin in the Unsaturated and Saturated Zone of the Velika Gorica Wellfield”, funded by the International Atomic Energy Agency (IAEA). The described method is very competitive (simple, faster and more cost-effective) compared to the existing methods currently used in most laboratories worldwide, and its implementation at the Faculty of Mining, Geology and Petroleum Engineering (University of Zagreb) enabled the development of new research on the estimation of the origin of nitrate in groundwater

Implementacija Ti(III) redukcijske metode u svrhu određivanja izotopnog sastava dušika (δ15N) i kisika (δ18O) iz nitrata

Pollution of surface and groundwater by nitrate (NO3–) is one of the most serious environmental problems worldwide. The crucial isotopes for the sources and dynamics of nitrogen (N) in the aquatic environment are the nitrogen and oxygen isotope data of NO3-. The stable isotope of nitrogen (δ15N) in dissolved nitrate has been most commonly used to estimate NO3- sources in groundwater. However, measurement of the stable nitrogen isotope alone does not provide a definitive determination of NO3– origin, so the stable oxygen isotope (δ18O) must be used, i.e., a dual isotope approach. The analysis of NO3- for both δ15N and δ18O has been made possible by the development of various laboratory methods for sample preparation, each with its own advantages and disadvantages. Current methods such as the cadmium reduction method (Azide method) or the bacterial denitrification method require toxic chemicals or anaerobic bacterial cultures for NO3- reduction to N2O gas. In 2019, a new sample preparation method was developed (ALTABET et al., 2019), which is a simple one-step conversion method that utilizes Titanium( III) chloride reagent to reduce NO3– to N2O within septum sample vials: 2NO3 – (aq) + 8Ti+3 + 10H+ → N2O(g) +8Ti+4 + 5H2O A single sample preparation takes only a few minutes, followed by a 24-h reaction that generates N2O headspace gas for δ15N and δ18O analysis by IRMS or laser spectrometer. Briefly, Ti(III) chloride is preconditioned with zinc metal powder about 30 minutes before sample preparation to ensure efficiency by removing Ti(IV). The volume ratio of sample to reagent for groundwater samples is 10:1, 20:1, or 40:1. We found that higher amounts of Ti(III) reagent (10:1 and 20:1 ratios) gave slightly more accurate δ18O values. The δ15N values were most inaccurate at ratios of 10:1 and 40:1, but were more accurate at a 20:1 ratio of sample to reagent. Therefore, a 20:1 ratio is considered practical for further measurements. To ensure consistent N2O yields and 15N and 18O results, the N concentrations in each vial must be identical for all samples, laboratory controls, and standards. This is achieved by adding an appropriate volume of sample, degassed deionized water, 10% hydrochloric acid, and the preconditioned Ti(III) chloride reagent. The δ15N and δ18O isotope analyses were performed using the Isotopic N2O Laser Analyzer (GLA451-N2OI3), which was acquired as part of the CRO7002 project “Using Nitrogen and Oxygen Stable Isotopes in the Determination of Nitrate Origin in the Unsaturated and Saturated Zone of the Velika Gorica Wellfield”, funded by the International Atomic Energy Agency (IAEA). The described method is very competitive (simple, faster and more cost-effective) compared to the existing methods currently used in most laboratories worldwide, and its implementation at the Faculty of Mining, Geology and Petroleum Engineering (University of Zagreb) enabled the development of new research on the estimation of the origin of nitrate in groundwater