Milica Kašanin-Grubin

Bioaccumulation of Heavy Metals and Microelements in Silver Bream (Brama brama L.), Northern Pike (Esox lucius L.), Sterlet (Acipenser ruthenus L.), and Common Carp (Cyprinus carpio L.) From Tisza River, Serbia

The aim of this study was to determine the concentrations of Al, As, B, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Se, Sr, and Zn in liver, gills, gonads, and brain of four ecologically different fish species in Serbia: piscivorous northern pike, benthivorous sterlet and silver bream, and omnivorous common carp. Fish were caught at four sites along the stretch of the River Tisza in the Pannonian part of Serbia during October 2010. Results revealed that heavy metals and microelements with the highest values in fish samples were Fe, Al, and Zn. The highest concentration of heavy metals and microelements was recorded in omnivorous common carp, and organs that most intensively accumulated the greatest number of metals were liver and gills, whereas the locality did not exert a marked impact on level of bioaccumulation.

Metals in the sediment and liver of four fish species from different trophic levels in Tisza River, Serbia

In aquatic environments metals originate from various natural and anthropogenic sources. The degree of contamination in fish tissues depends on the pollutant, fish species, their mode of feeding, sampling site and trophic level. This study presents concentrations of Al, As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Se, Sr and Zn in sediment and liver of four ecologically different fish species: piscivorous northern pike (Esox lucius L.), benthivorous sterlet (Acipenser ruthenus L.) and silver bream (Brama brama L.), and omnivorous common carp (Cyprinus carpio L.). Fish were caught at four sites along the stretch of the River Tisza in Serbia during October 2010. The concentrations of metals have been assessed using the inductively coupled plasma – optical emission spectrometry. Results revealed that metals with the highest values in sediment and fish samples were Al and Fe, respectively and sometimes concentrations of Zn are in the same order of magnitude as Fe concentrations. The highest concentration of metals was recorded in omnivorous common carp.

The Role of Lithology

Abstract Badlands can develop on bedrock and/or weathered material, the characteristics of which play a key role on hillslope processes in a range of climate conditions. Therefore, fundamental attention should be given to badland materials, the main features of which are grain size, clay mineralogy and physico-chemical characteristics. The typical weathering profile consists of crust, subsurface and unweathered material, but depending on climatic, lithological, topographic and hydrological factors, the properties and appearance of both surface and subsurface materials change over time. Through time, regolith formed on erodible and dispersive bedrock materials tends to stabilize, again as a function of slope and climate conditions because prolonged precipitation can cause decrease in surface strength and runoff and reduce the dispersivity of the surface. Vegetation also has distinct role in stabilizing the clayey sediments due to lowering the dispersivity in the upper horizon of the badland material, even though such stabilization is often not permanent and erosion processes can sometimes reoccur. Finally, all the above cited factors and properties of badland materials play a complex and key role in the development of different geomorphic processes and related landforms.

Organic geochemical approach in the identification of oil-type pollutants in water and sediment of the River Ibar

In this paper an applied organic geochemical approach in studying the nature of organic matter (OM) in water and sediments of the River Ibar (upsteream and downstream of towns Kosovska Mitrovica and Kraljevo) was used. A forensic approach that relies on the fact that the composition of OM of recent sediments and oil varies due to geological age and maturity was applied. The content of bitumen, its group composition of saturated, aromatic and NSO compounds (nitrogen, sulphur, and oxygen compounds) and the distribution of n -alkanes in saturated fractions identified by gas chromatography-mass spectrometry (in almost all samples incorporated into the colloidal micelles formed by water and NSO compounds) could not answer the question whether OM in isolated extracts has native or anthropogenic origin. However, the presence of sterane and terpane, with the distribution of structural and stereochemical isomers characteristic of oil, as a form of most matture OM in sediments, unambiguously confirmed presence of oil type pollutants in anlayzed samples. Based on significant differences in the distributions of these polycyclic alkane (water-water, sediment-sediment and water-sediment), it was concluded that they have more than one source of pollution, and that the River Ibar is permanently exposed to this form of pollution.

Stone pillar rockfall in Danxia landform area, Mt. Langshan, Hunan Province, China

Abstract A typical Danxia stone pillar, Leipishi I, in the World Natural Heritage site at Mt. Langshan, China, collapsed on 2 November 2009. To understand the mechanism controlling this rockfall event, uniaxial compressive strength, tensile strength, resistance against sulfuric acid, and freezing and thawing properties were analyzed from 44 sandstone and conglomerate cores collected from the Lanlong Formation, the only exposed formation on Mt. Langshan. In addition, four rock slices were created for analysis under a polarizing microscope. A detailed reconstruction of the geometry and restraint conditions of the stone pillar in place before the rockfall occurred permitted an estimation of the stress state before collapse using 3D finite-element code. The results show that the rapid retreat of soft, intercalated rock layers due to weathering can profoundly change the stress state within the rock body, causing compressive or tensile stresses to rise above compressive or tensile strengths in specific sections of a rock body, and causing partial or complete collapse.