Comprehensive characterization of bentonites from Croatia and neighboring countries

Bentonites are an important industrial resource and are also interesting from the mineralogical point of view. The main component of bentonites is a mineral from the smectite group in which chemical and structural variations, influencing bentonite properties, provide a great deal of interesting research topics. The aim of this study was to better describe bentonites from 11 known deposits from Croatia and neighbouring countries: Bednja, Bunarić, Draga, Divoselo, Sjeničak, Paripovac, Lončarski Vis and Poljanska Luka (Croatia), Zaloška Gorica (Slovenia), Šipovo (Bosnia and Herzegovina) and Vranjska Banja (Serbia). Thirteen samples were analysed using several available techniques in order to obtain the data necessary for currently accepted bentonite classification. The mineralogical composition was analysed using XRD and FTIR, and crystallo-chemical properties were investigated by thermal analysis, CEC determination with ammonium index cations, chemical analyses (ICP-AES and ICP-MS) and Mössbauer spectroscopy. The results showed that the main mineral constituent of most local bentonite deposits is a Fe-poor smectite, with a predominantly medium layer charge mostly as a result of octahedral substitutions, with calcium or sodium cations occupying the interlayer. Nevertheless, the variations between samples are prominent enough to provide a good overview of the range of crystallo-chemical properties which exist in different smectites resulting in varying bentonite properties.</p

Availability of Selected (Pollutant) Elements and their Influence on Soil Composition in Urban Area

Interest in growing fruits and vegetables in private gardens is rising due to nowadays ecological awareness. Avoiding artificial fertilizers and plant protection products does not guarantee the absence of toxic substances, especially heavy metals in the soil and thus in the fruits harvested. Due to either geological bedrock weathering or environmental pollution, garden soils may be rich in certain potentially toxic elements. In the present study ten garden soils from central Croatia have been analysed by the BCR method for the contents and bioavailability of aluminium, cadmium, chromium, cobalt, copper, lead, manganese, nickel and zinc. The total amounts of the elements are in the concentration range as reported for agricultural soils in different geographical regions. Only two soils of the capital Zagreb have higher concentrations of pollutant metals, such as chromium, cobalt, copper, lead, manganese and zinc. Regarding nutrients, all soils have met the needs of common garden plants

Distribution of sulphur, phosphorous, iron, and trace elements in bottom sediment cores, mussels and fish from the Punat Bay (Island of Krk, Croatia)

Ships and associated anthropogenic activities release a number of contaminant elements into the marine environment which can be particularly concentrated in restricted circulatory environments including Bays and marinas. One such locality is a Punat Bay, situated at the southern coastline of the island of Krk (west Croatia), which is the largest Croatian marina. The aim of this study was to examine depth profiles of sulfur (S), phosporous (P), iron (Fe), and trace elements (As, Ba, Be, Cd, Co, Cr, Cu, Hg, Mn, Mo, Ni, Pb, Sn, Sr, Ti, U, V, Y, and Zn) in six sediment cores (down to 20-30 cm), and from mussels and fish from Punat Bay, by determining their levels with ICP-OES. Data analysis showed that the majority of variables were elevated in a sediment core located closest a port of the marina. Minimum to maximum S, P, and Fe levels in sediments were as follows: 0.4-2.4%, 0.04-320 mg/kg, and 0.2-2.3%, respectively. Correlations among S, P, Fe, and various trace elements were mostly positive (p<0.05). Trace elements were not increased in mussels and fish. This paper shows that the Punat marina has only a limited impact on the environmental status. Several potentially toxic trace elemens (Pb, Cu, etc.) were found to be elevated in a sediment core located closest to the marina

Environmental geochemistry of the polymetallic ore deposits: Case studies from the Rude and the Sv. Jakob historical mining sites, NW Croatia

This paper presents the results of the sampling surveys carried out in order to evaluate the environmental impact of the Rude and the Sv. Jakob historical mining sites, NW Croatia. The studied polymetallic ore deposits are differing in the mineralogical and geochemical features as well as in the host rock lithology. The Rude Fe-Cu-Pb-Zn-Ba deposit is hosted by Permian siliciclastic sediments. Siderite, hematite, galena, sphalerite, chalcopyrite, pyrite, barite and gypsum are the major ore minerals, whereas quartz is the principal gangue mineral. The Sv. Jakob Pb-Zn-Ag deposit occurs in the Middle Triassic dolostone. The most abundant ore minerals are galena, sphalerite and pyrite. Calcite and quartz represent the principal gangue minerals. Although the deposits represent the potential sources of numerous toxic metals, the pollution of the drainage streams and associated stream sediments was not recorded. The studied mining sites are characterized by the high carbonate/sulfide ratios responsible for the alkaline character of the drainage streams. Consequently, the mining sites have very low potential for generation of acid mine drainage as well as very low potential for leaching of heavy metals into the drainage systems. Furthermore, the presented study revealed that the populated areas (stream waters with decreased redox potential, increased organic matter content, high NO3-, NH4+ and PO43- concentrations; stream sediments enriched in exchangeable Pb and Zn) and the Sava river alluvium (overflowing streams enriched in Hg) represent bigger environmental threat than the investigated polymetallic ore deposits. </span

Geochemistry of Croatian superhigh-organic- sulphur Raša coal, imported low-S coal, and bottom ash: their Se and trace metal fingerprints in seawater, clover, foliage, and mushroom specimens

The Labin city area has represented the major Croatian coal mining, metal industry, and coal- fired electricity centre for more than two centuries. The domestic superhigh-organic- sulphur (SHOS) Raša coal is a unique variety compared to other coal types worldwide, based on its highest organic sulphur values, up to 11%. It was utilized in the Plomin coal-fired power plant during the period 1970-2000, and was replaced by an imported low-S coal afterwards. This paper presents the levels of S, Se, V, U, Hg, Sr, Cd, Cr, Pb, Cu, and Zn in the two coal types, their bottom ash, seawater, and plant (clover, mushroom, and foliage) specimens collected from the Labin city area, while the sulphate was measured in surface stream water. Their levels were compared with relevant legislative as well as the published data from different world localities. Data analysis was interpreted in the context of past and recent coal combustion activities

Distribution of copper and zinc in the soil of an industrial zone in the city of Garešnica, Croatia

Soils from an industrial zone in Garešnica, Croatia have been analysed by EDXRF and XRD. In the area surrounding two adjacent factories named \u27Bakrotisak\u27 and \u27Croatia Protekt\u27, thirty soil sites (depth 5-15 cm) were sampled in December 2007, together with five soil sites from the forest (check samples) situated 0.5 km away. The locality was selected for its periodical, industrially induced environmental pollution which affects nearby streams and fish ponds, resulting in occasional fish kills in the region. Analysis included the determination of the soil mineralogy, total organic matter contents, cation exchange capacity, bulk multi-element composition and heavy metal levels in leachates (exchangeable fraction). Multi-element concentrations in the check samples constituted natural levels based on their perfect normal distributions. The Kruskal-Wallis test showed higher, statistically significant (P = 0.0005) concentrations of Cu in the soil surrounding \u27Bakrotisak\u27 compared to the check samples. Furthermore, leaching analysis confirmed the copper contamination of the \u27Bakrotisak\u27 soil by highly significant positive correlation (the Kendall\u27s Tau correlation coefficient >0.99) between its extractable Cu and total Cu levels. Moreover, enrichment factors based on Al as a reference element were found to be >2 for approximately 50% samples of the \u27Bakrotisak\u27 soil, suggesting its moderate anthropogenic contamination

Kemijski oblici bakra i cinka u tlu nasada jabuka u selu Bukevje (Hrvatska) ispitivani revidiranom BCR ekstrakcijskom shemom u četiri koraka

The aim of this study was to establish the fractionation of copper and zinc in a small apple orchard using the revised (four-step) Bureau Communautaire de Référence (BCR) sequential extraction procedure and assess their potential mobility in soil. Soil samples were collected at the depth of 10 cm to 25 cm, sixteen from the orchard and five control samples from a meadow located some 200 m away from the orchard. As the distribution of trace-element concentrations in the control samples was normal, they were used for comparison as background levels. We also determined soil mineralogical composition, carbonate content, soil pH, cation exchange capacity, and soil organic matter. The extraction yields of Cu and Zn from the control soil were lower than from the orchard soil (25 % vs. 34 % and 47 % vs. 52 %, respectively), which pointed to natural processes behind metal bonding in the control soil and greater influence of man-made activities in the orchard soil. Compared to control, the orchard soil had significantly higher concentrations of total Cu (P=0.0009), possibly due to the application of Cu-based fungicides. This assumption was further supported by greater speciation variability of Cu than of zinc, which points to different origins of the two, Cu from pesticides and Zn from the parent bedrock. Copper levels significantly better (P=0.01) correlated with the oxidisable fraction of the orchard soil than of control soil. Residual and organically bound copper and zinc constituted the most important fractions in the studied soils. However, the use of Cu-based fungicides in the apple orchard did not impose environmental and health risk from Cu exposure.Analizirani su uzorci tla iz obiteljskog voćnjaka u selu Bukevju kako bi se utvrdilo ponašanje metala u tragovima u okolišu u kontekstu poljoprivrednih postupaka proteklih nekoliko desetljeća. Unos kemijskih sredstava za zaštitu bilja navodno je nizak. Nakon provedene tzv. BCR sekvencijske ekstrakcijske analize, kemijski oblici bakra i cinka razmotreni su iz geokemijskoga/geološkoga gledišta. Uzeto je šesnaest uzoraka tla iz voćnjaka te pet uzoraka kontrolnog tla s obližnje livade. Analize su obuhvaćale određivanje mineralnog sastava tla, kationsko izmjenjivačkog kompleksa (KIK), pH tla i gubitka žarenjem. Koncentracije mjerenih varijabli u kontrolnim uzorcima, određene XRF metodom, upućuju na njihove prirodne razine na temelju normalnosti raspodjela. Tlo iz voćnjaka neznatno je onečišćeno bakrom, moguće od primjene fungicida na bazi bakra, što je utvrđeno Mann-Whitneyevim U testom, koji je pokazao statistički značajno više koncentracije ukupnog Cu (P = 0.0009) u tlu voćnjaka u usporedbi s uzorcima kontrolnog tla. Učinkovitost BCR ekstrakcije bakra i cinka izračunata za kontrolno tlo (25 % odnosno 47 %) bila je niža nego ona izračunata za tlo iz voćnjaka (34 % odnosno 52 %). Bakar, potječući djelomice od fungicida, pokazao je veću specijacijsku varijabilnost u istraživanim tlima u usporedbi s cinkom, za koji se pretpostavlja da potječe uglavnom od trošenja stijenske podloge. Mann-Whitneyev U test pokazao je statistički značajno (P = 0,01) više vrijednosti Cu povezane s frakcijom tla iz voćnjaka podložnoj oksidaciji u odnosu na istu frakciju kontrolnih uzoraka. Bakar i cink u istraživanim tlima čvrsto su vezani za rezidualnu i organsku frakciju, a ukupne im vrijednosti ne premašuju maksimalno dopuštenu količinu onečišćujućih tvari u poljoprivrednom zemljištu, pa ne bi trebali predstavljati toksikološku opasnost za ljudsko zdravlje

Retrieving planktonic foraminifera from lithified rocks, examples from the Eocene limestones and marls (External Dinarides, Croatia)

Paleoecologic (paleoclimatologic) and biostratigraphic studies of pelagic and deep-water deposits rely on the identification of planktonic foraminifera. Here we report and compare the results of planktonic foraminiferal assemblages from the Middle Eocene indurated limestones and marls collected in the External Dinarides extracted with acetic acid of different concentrations (50%, 60%, 70% and 80%) and different reaction (exposure) times. The deposits originated within the Dinaric foreland basin, have been assigned to the so-called Transitional beds and Flysch, and are characterized by different ratio of carbonate content and degree of lithification. The aim of this paper is to compare the efficiency of the laboratory procedures for obtaining isolated specimens and to evaluate the impact of preparation procedure on the quality of tests (complete test vs. secondary dissolution effects). For each acetic concentration we assessed: (1) the effectiveness of the treatment in terms of the time required for successful extraction of planktonic foraminifera, and (2) the degree of dissolution by analyses of dissolution proxies, including the weight percentage of sieved residues after disaggregation and preservation features of the tests. Our results indicate that accurate taxonomic analysis of carbonate rocks requires the use of 60% acetic acid for a shorter reaction time, and hydrogen peroxide methods for marls