Karakterizacija šljake i pepela odloženog u Kaštel Gomilici

The objective of this study was to determine the chemical, radiological and leaching properties of slag and ash produced by a thermoelectric unit of a former factory Adriavinil and deposited in the area of Kaštel Gomilica near Split, Croatia. A total of 33 samples were analysed. The bioavailable fraction of the slag and ash was estimated using different leaching tests. The waste material was characterized by a high activity of naturally occurring radionuclides 238U, 235U and 226Ra and by elevated concentrations of heavy metals. The concentrations of most heavy metals were three to four times as high as in the common soil. Uranium slag and ash concentration was almost 40 times higher than in control soil. More than 37 % of the total U could be removed from the slag and ash with the sea water.U radu su kemijski i radiološki okarakterizirani uzorci šljake i pepela. Otpadni materijal je nastao radom termoelektričnog postrojenja bivše tvornice “Adriavinil”, a odložen je u Kaštel Gomilici u Hrvatskoj. Ukupno su analizirana 33 uzorka. Biodostupnost frakcija šljake i pepela određena je različitim testovima za izluživanje. U otpadnome materijalu određena je velika aktivnost radionuklida iz prirodnog niza, 238U, 235U i 226Ra, i povišene koncentracije teških metala. Koncentracije veæine teških metala 3 do 4 puta su veæe nego u kontrolnim uzorcima, dok je koncentracija urana veæa 40 puta. Utvrđeno je da se više od 37 % ukupnog urana iz uzorka može ukloniti izluživanjem u morskoj vodi

Long-Term Isotope Records of Precipitation in Zagreb, Croatia

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, delta2H, delta18O, and deuterium excess) and compare them to basic meteorological data. The aim was to see whether isotope composition reflected observed climate changes in Zagreb: a significant increase in the annual air temperature and larger variations in the precipitation amount. Annual mean delta18O and delta2H values showed an increase of 0.017 ‰ and 0.14 ‰ per year, respectively, with larger differences in monthly mean values in the first half of the year than in the second half. Mean annual d-excess remained constant over the whole long-term period, with a tendency for monthly mean d-excess values to decrease in the first half of the year and increase in the second half due to the influence of air masses originating from the eastern Mediterranean. Changes in the stable isotope composition of precipitation thus resembled changes in the temperature, the circulation pattern of air masses, and the precipitation regime. A local meteoric water line was obtained using different regression methods, which did not result in significant differences between nonweighted and precipitation-weighted slope and intercept values. Deviations from the Global Meteoric Water Line GMWL (lower slopes and intercepts) were observed in two recent periods and could be explained by changes in climate parameters. The temperature gradient of delta18O was 0.33 ‰/°C. The tritium activity concentrations in precipitation showed slight decreases during the last two decades, and the mean A in the most recent period, 2012–2018, was 7.6 ± 0.8 Tritium Units (TU)

Isotope Composition of Precipitation, Groundwater, and Surface and Lake Waters from the Plitvice Lakes, Croatia

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 correlation of the tritium activity concentration in the PL and Zagreb precipitation implies that the tritium data for Zagreb are applicable for the study of the PL area. The best local meteoric water line at PL was obtained by the reduced major axis regression (RMA) and precipitation-weighted ordinary least squares regression (PWLSR) approaches: δ2HPWLSR = (7.97 ± 0.12) δ18O + (13.8 ± 1.3). The higher deuterium excess at PL (14.0 ± 2.2 ‰) than that at Zagreb reflects the higher altitude and influence of the Mediterranean precipitation. The δ2H in precipitation ranges from −132.4‰ to −22.3‰ and δ18O from −18.3 ‰ to −4.1‰. The much narrower ranges in the groundwater (<1‰ in δ18O, <10‰ in δ2H) indicate the good mixing of waters in aquifers and short mean residence times. The higher average δ2H in all three karst springs observed after 2003 can be attributed to the increase in the mean air temperature. The mean δ2H and δ18O values in the surface and lake water increase downstream due to the evaporation of surface waters. There is no significant difference between the surface water line and the lake water line (2011–2014). The stable isotope composition of the surface and lake waters reacts to extreme hydrological conditions

Inertizacija galvanskog mulja s pomoću kalcijeva oksida, aktivnog ugljena i fosforne kiseline

In this study we compared three methods for the treatment of electroplating sludge highly loaded with zinc and iron: (1) calcium oxide-based solidifi cation/stabilisation; (2) conversion into inert material by adsorption of organic and inorganic pollutants onto activated carbon; and (3) conversion of mobile waste components into insoluble phosphates. All three methods proved highly efficient in the conversion of hazardous waste into inert material. Under optimum treatment conditions zinc concentration in the leachate of solidified waste was reduced by 99.7 % compared to untreated sludge. Zinc retention effi ciency in the waste treated with activated carbon and phosphoric acid was 99.9 % and 98.7 %, respectively. The advantages of electroplating sludge treatment with activated carbon over the other two methods are high sorption capacity, insignificant pH and volume changes of the sludge, and simple use.U radu su prikazani i uspoređeni rezultati triju metoda obrade galvanskog mulja visoko opterećenog cinkom i željezom: (1) solidifi kacija/stabilizacija otpada primjenom kalcijeva oksida; (2) inertizacija otpada adsorpcijom organskog i anorganskog opterećenja na aktivni ugljen; (3) prevođenje mobilnih komponenata otpada u teško topljive fosfate. Sve tri metode pokazale su se efikasnima u prevođenju opasnog otpada u inertno stanje. Kod optimalnih uvjeta koncentracija cinka u eluatu solidificiranog otpada snizila se za 99,7 % u odnosu prema neobrađenom otpadu. Efikasnost retencije cinka u otpadu inertiziranom aktivnim ugljenom iznosila je 99,9 %, a fosfornom kiselinom 98,7 %. Prednost inertizacije aktivnim ugljenom u odnosu prema ostalim dvjema metodama očituje se visokim sorpcijskim kapacitetom, neznatnim promjenama pH-vrijednosti i volumena tretiranog otpada, kao i jednostavnošću primjene

137Cs Sediment Profiles as a Tracer of Marine Sedimentation Processes in a Semi-Enclosed Bay Affected by Anthropogenic Releases—Example of Kaštela Bay (Adriatic Sea, Croatia)

Kaštela Bay was taken as a model to study sedimentation processes using the vertical sediment profiles of 137Cs massic activities. The aim was to distinguish the sedimentation conditions in different parts of the Bay and to partly determine the pathways of terrigenous input into the Bay. The purpose was to demonstrate that 137Cs profiles are applicable in differentiating sedimentation processes. It was found that mostly continuous, undisturbed sedimentation takes place in the central and south parts of the Bay ; the sedimentation conditions in the west part of the Bay are more complicated. The west part is characterised by the extremely slow sedimentation of the coarse-grained sediment or even by erosion and selective resuspension of the fine-grained particles followed by resedimentation in other parts of the Bay. It was also observed that the upper 10 cm of the sediment is the most exposed to homogenisation. The strong influence of the Jadro River and anthropogenic activities in the east part of the Bay are reflected in the higher 137Cs activities, strong sediment mixing, and increased sediment input. This study shows that the 137Cs profiles can provide comprehensive insights for the whole study region when a sophisticated sampling layout is deployed. The results of the study are applicable to other aquatic environments with comparable processes and sedimentary environments