Environmental and Economic Criteria in Ranking of Copper Concentrates

Influence of the economic criterion, called Profit, on the ranking of copper concentrates is investigated. Values of the criterion, which correspond to alternatives, are derived as earning values obtained by the exploitation of individual concentrates. Various scenarios with respect to the weight w ₁₄, corresponding to the additional economical criterion, are defined and solved. A discrete set of results is generated, applying DECISION LAB software implementation of the PROMETHEE-GAIA methodology. Interpolating these results, we derived continuous interpolation functions which compute necessary quantities of concentrates for each real value of w ₁₄ within the interval [0, 100].     

Long-term seasonal changes of the Danube River eco-chemical status in the region of Serbia

Seasonal spatial and temporal changes of selected eco-chemical parameters in section of the Danube River flowing through Serbia were analyzed. Data for electrical conductivity (EC), dry and suspended matter, residue on ignition, chemical oxygen demand (COD), biochemical oxygen demand (BOD-5), ultraviolet extinction, dissolved oxygen (DO), oxygen saturation, pH, nitrates, total phosphorus, and nitrogen were collected between 1992 and 2006. The use of monthly medians combined with linear regression and two-sided t test has been proven to be the best approach for resolving trends from natural variability of investigated parameters and for determining trend significance. Patterns of temporal changes between different months were examined. It was also determined that spatial trends of some parameters oscillate in predictable manner, increasing in one part of the year and declining in the other. Regression slope coefficients, an excellent indicator for determining when the water quality is changing the most along the course of the Danube, reach their maximum during summer for temperature (t), electric conductivity, nitrates, and total N, while in the same season suspended matter, COD, BOD-5, DO, and oxygen saturation coefficients reach their minimum. Correlations for used data sets of selected parameters were analyzed for better understanding of their behavior and mutual relations. It was observed that as Danube flows through Serbia, its general eco-chemical status either stagnates or improves, but the rate of river self-purification often depends on the season of the year.     

The responses of the hepatosomatic index (HSI), 7-ethoxyresorufin-O-deethylase (EROD) activity and glutathione-S-transferase (GST) activity in sea bass (Dicentrarchus labrax, Linnaeus 1758) caged at a polluted site: implications for their use in environmental risk assessment

The present study investigates the response of three hepatic biomarkers in adult sea bass (Dicentrarchus labrax, Linnaeus 1758) caged at a wastewater outlet of an oil refinery with fish caged at a pristine site used as controls. The biomarkers that were investigated were the hepatosomatic index (HSI), 7-ethoxyresorufin-O-deethylase (EROD) activity and glutathione-S-transferase (GST) activity. In addition, we have measured the levels of polycyclic aromatic hydrocarbons (PAHs) and selected heavy metals (lead, cadmium, mercury, copper and zinc) in sediment samples at the polluted site. Although the polluted site had high environmental levels of PAHs and heavy metals, there was no difference in hepatic EROD activity and HSI between fish caged at the polluted site and controls. On the other hand, GST activity was significantly lower in fish caged at the polluted site compared to controls. Our results point out that the studied biomarkers have limited use in environmental risk assessment studies, at least when caged adult sea bass is used as the sentinel species and complex toxicant mixtures are involved.     

Socio-economic features of commercial fishery in the bordering upper Danube River area of Serbia

The multidisciplinary socio-economic study of fisheries in the bordering part of the Danube River between Serbia and Croatia (at the following sites: Apatin, Ba?ka Palanka, Ba?ko Novo Selo, Bezdan, and Sombor) that was performed in order to investigate various aspects of fish resource utilization (management, policy of protection and exploitation of freshwater fishery resources, present fisheries legislation, catch statistics), was realized during 2004 and 2005. Data were collected via survey with a structured interview. Socio-economic circumstances, together with ecological factors, have had an influence on the fish stock and number of commercial fishermen. Awareness of the occurring problems, both economic and ecological ones, is apparent, regardless of whether it is assessed in the field of commercial or recreational fishing. Fishery sector in Serbia is in a prolonged process of transition, with the enforcement of fishing regulations, but also the lack of control that leaves space for illegal commercial fishing. The statements, consciousness, experience and behavior of commercial fishermen represent a good basis for planning the sustainable development of fishing in this section of the Danube River.     

Edaphic factors affecting the vertical distribution of radionuclides in the different soil types of Belgrade, Serbia

The specific activities of natural radionuclides ((40)K, (226)Ra and (232)Th) and Chernobyl-derived (137)Cs were measured in soil profiles representing typical soil types of Belgrade (Serbia): chernozems, fluvisols, humic gleysols, eutric cambisols, vertisols and gleyic fluvisols. The influence of soil properties and content of stable elements on radionuclide distribution down the soil profiles (at 5 cm intervals up to 50 cm depth) was analysed. Correlation analysis identified associations of (40)K, (226)Ra and (137)Cs with fine-grained soil fractions. Significant positive correlations were found between (137)Cs specific activity and both organic matter content and cation exchange capacity. Saturated hydraulic conductivity and specific electrical conductivity were also positively correlated with the specific activity of (137)Cs. The strong positive correlations between (226)Ra and (232)Th specific activities and Fe and Mn indicate an association with oxides of these elements in soil. The correlations observed between (40)K and Cr, Ni, Pb and Zn and also between (137)Cs and Cd, Cr, Pb and Zn could be attributed to their common affinity for clay minerals. These results provide insight into the main factors that affect radionuclide migration in the soil, which contributes to knowledge about radionuclide behaviour in the environment and factors governing their mobility within terrestrial ecosystems.     

The determination of the extractability of selected elements from agricultural soil

Concentrations of Ag, Al, Ba, Cd, Co, Cr, Cu, Fe, K, Mn, Na, Ni, Pb, Sr, and Zn—isolated by sequential extraction steps from apple orchard soil—were analyzed by inductively coupled plasma-atomic emission spectroscopy and compared to the total amount of metal in soil determined by XRF. The extractable amount of each metal was calculated by the extraction yields of the four steps. The LODs of the different elements in all extracts ware below 3 μg/L except for Ba (steps 1 and 2), Cu (step 1), Fe (all steps), K (steps 1–3), Mn (step 2), Na (steps 1–3), Ni (step 1), Pb (steps 1 and 4), and Zn (steps 1 and 2). The highest LOD (>10 μg/L) was found for Fe, K, and Na (step 1). The recovery of all metals after four sequential extraction steps was 90–112%. The repeatability (<1.1%), the intermediate precision (<5.3%), the day-to-day reproducibility (<6.2%), and the overall uncertainty of measurement (approximately 4–8.5%) for all analyzed metals supports the choice of the method used.     

The assessment and prediction of temporal variations in surface water quality—a case study

In order to optimize the processes of sampling, monitoring, and management, the initial aim of this paper was to develop a model for the definition and prediction of temporal changes of water quality. In the case of the Morava River Basin (Serbia), the patterns of temporal changes have been recognized by applying different multivariate statistical techniques. The results of the conducted cluster analysis are the indicators of the existence of the three monitoring periods: the low-water, transitional, and high-water periods, which is in accordance with changes in the water flow in the analyzed river basin. A possibility of reducing the initial data set and recognizing the main pollution sources was examined by carrying out the principal component/factor analysis. The results indicate that the natural factor has a dominant influence in temporal groups. In order to recognize the discriminatory water quality parameters, a discriminant analysis (DA) was carried out. Conducting the DA enabled a significant reduction in the data set by the extraction of two parameters (the water temperature and electrical conductivity). Furthermore, the artificial neural network technique was used for testing the possibility of predicting changes in the values of the discriminant factors in the monitoring periods. The reliability of this method for the prediction of temporal variations of both extracted parameters within all temporal clusters has been proven.     

Periphyton Developed on Artificial Substrates: Effect of Substrate Type and Incubation Depth

The aim of this study was to assess the effect of substrate type and incubation depth on periphyton that had developed on artificial substrates. Uniform rectangular tiles made out of artificial substrates: glass, ceramic, willow tree and yew tree, were fixed on a floating buoy and deployed at three different depths in a photic zone of the Sava Lake (Belgrade, Serbia). Non-taxonomic attributes in the developed biofilm were estimated week-by-week from the start of the experiment in July, until its end in September 2014. Through assessment of substrate type and depth of incubation effect we concluded that these parameters for the fact influence periphyton development and composition. Glass was preferred by autotrophic component over ceramic and wooden substrates. In general, substrate type effect was diminished by increasing incubation depth. When non-taxonomic parameters are to be used in biomonitoring studies, our results suggest that glass substrate and shallow layer of water column (up to 50 cm) for incubation should be preferred.     

Evaluation and validation of two different chromatographic methods (HPLC and LC-MS/MS) for the determination and confirmation of ochratoxin A in pig tissues

This study was undertaken to compare two different analytical methods for the determination and confirmation of ochratoxin A (OTA) in blood serum, kidney and liver of pigs. Sample clean-up was based on liquid-liquid phase extraction. The detection of OTA was accomplished with high-performance liquid chromatography (HPLC) combined either with fluorescence detection (FL) or electro spray ionization (ESI+) tandem mass spectrometry (MS–MS). Comparative method evaluation was based on the investigation of 90 samples of blood serum, kidney and liver per animal originating from different regions of Serbia. The analytical results are discussed in view of the respective method validation data and the corresponding experimental protocols. In general, analytical data obtained with (LC–MS–MS) liquid chromatography electro spray tandem mass spectro metry detection offered comparable good results at the sub-ppb concentration level. The results indicate that the liquid chromatography electro spray tandem mass spectrometric (LC-MS/MS) method was more specific and sensitive for the analysis and confirmation of ochratoxin A in pig tissues then high pressure liquid chromatography (HPLC) method after methylation of OTA.