115 research outputs found

    Evolucija trofičkog statusa jezera Palić, Srbija

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    The Palic Lake is a shallow lake typical for the Pannonian Plain. Due inadequate water quality, it was dried out in 1971 and re-established in 1977 and since than its trophicity has been worsening. Investigation of the long-term changes in the trophic state of this lake were tracked over the total phosphorous (TP), total nitrogen (TN), chlorophyll-a and Secchi disk transparency (SDT), expressed as the Carlson trophic state index (TSI). Regarding the TSI values, the water of the Palic Lake has been constantly evolving from eutrophic to hypereutrophic. TN/TP values lt 10 indicate that nitrogen is the limiting factor for algal growth.Jezero Palić je plitko jezero tipično za Panonsku niziju. Zbog neadekvatnog kvaliteta vode isušeno je 1971. godine i sanirano do 1977. godine i od tada se njegov trofički status pogoršava. Dugoročna ispitivanja promene trofičkog statusa, koja obuhvataju analize količine ukupnog fosfora, ukupnog azota, hlorofila-a i providnosti vode preko Secchijevog diska, izražena su preko Karlsonovog indeksa trofičkog statusa. Vrednost pomenutog indeksa ukazuje da je voda jezera Palić u eutrofičnoj i hipereutrofičnoj klasi. Odnos ukupnog azota i ukupnog fosfora, koji je manji od 10 ukazuje na to da je azot limitirajući faktor za rast algi

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

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    The Danube River is an international river, one part of which flows through Serbia. The eco-chemical status of the Danube River is a constant topic of interest both at the local level, in each country through which the Danube flows, and at the international level. General interest to ensure the sustainable and equitable use of waters and freshwater resources in the Danube River Basin led to the development of a system for monitoring the river, which has produced data sets of its eco-chemical status. These have been collected over many years in Serbia; however, the present interest was focused only on the period from 1992 until 2006, i.e., a 15-year period. The process of defining trends of selected eco-chemical parameters, using linear regression analysis with a defined level of significance, and their separation from natural variability is of the highest importance for defining the changes in the water parameters. Through them, the fate and behavior of the eco-chemical parameters of the Danube in Serbia can be recognized and the prediction of their trends in the near future can be attempted. The obtained results revealed a constant improvement and acceptable trends of the eco-chemical status of the Danube River, as well as, substantial differences in the quality of the inflowing and out flowing water

    Local electron density models for Tl to Pb conversion in lorandite

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    The nuclear conversion of 205Tl to 205Pb by neutrino capture, lorandite (TlAsS2) converts into Pb-bearing lorandite (Tl1-xPbxAsS2) where x is a very small number. Having used a highly simplified cluster model of lorandite, we intended to calculate the electron density of Tl and its neighbouring atoms by the quantum chemical discrete variational method [5,6]. Substituting Pb for Tl in the lattice site of Tl and calculating the difference existing between these two clusters, we would like to discuss the possible changes of the cluster's stability and the relative binding between TlS and PbS in lorandite. © 1988

    Procena potencijalnog rizika po zdravlje ljudi usled prisustva teških metala u zemljištu centralne zone Beograda

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    An investigation of the soil quality in the centre of Belgrade was performed to define how seriously the soil is polluted. On the basis of the heavy metal content (Zn, Cd, Pb, Co, Ni, Cu, Cr and Mn), the potential health risk assessment calculated for a lifetime of exposure (ingestion and inhalation), based on the USEPA model, was determined as the cumulative carcinogenic and non-carcinogenic risk for children and adults. The study proved that soil contamination in Belgrade is not insignificant; risk assessment indicated that the carcinogenic risk is completely insignificant but the cumulative non-carcinogenic risk tends to became significant, mainly for children, since it approaches unacceptable values. There is no particularly dangerous single heavy metal, but their cumulative effect, expressed as Child Soil Ingestion Hazardous Index, is for concern.Ispitivanje zemljišta centralne zone Beograda rađeno je sa ciljem da se odredi nivo njegove zagađenosti teškim metalima. Polazeći od sadržaja teških metala (Zn, Cd, Pb, Co, Ni, Cu, Cr i Mn) procenjen je kumulativni potencijalni kancerogeni i nekancerogeni zdravstveni rizik (za ingestiju i inhalaciju) za životni vek čoveka, dece i odraslih, polazeći od modela koji je razvila američka agencija za zaštitu životne sredine. Istraživanja pokazuju da zagađenje zemljišta u Beogradu nije zanemarljivo iako procena kancerogenog rizika ukazuje da je on zanemarljiv, ali da nekancerogeni rizik postaje značajan, posebno u slučaju dece. Za sada ne postoji određeni teški metal koji se može identifikovati kao opasan, ali kumulativni efekat svih ispitivanih metala iskazan kroz ingestioni hazardni indeks za decu postaje zabrinjavajući pošto se približava vrednostima koje se smatraju nepovoljnim

    Dugotrajni organski zagađivači (POPs)

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    Persistent organic pollutants (POPs) are ubiquitous in all environmental media. Because of their persistence, they are present even in regions where they haven't been released before. POPs are toxic even in very low concentrations, many of them being carcinogenic. Basic representatives and groups of POPs, sources in the environment, ways of transport and elimination, impact to the human health and the environment are presented in this article. At the end Stockholm Convention is mentioned, an international legally binding agreement on persistent organic pollutants.Dugotrajni organski zagađivači (persistent organic pollutants - POPs) su jedinjenja široko rasprostranjena u svim medijima životne sredine. Zbog svoje dugotrajnosti nepromenjeni prelaze velike razdaljine, usled čega se javljaju i u regionima u kojima nikad nisu bili ispuštani. Toksični su u vrlo malim koncentracijama, a mnogi od njih su kancerogeni. U članku su pobrojani osnovni predstavnici i grupe, predstavljeni su izvori emitovanja u životnu sredinu, načini transporta i eliminacije, uticaj na životnu sredinu i zdravlje. Na kraju je kratak prikaz Stokholmske konvencije, međunarodnog dokumenta nastalog radi regulacije POPs-ova

    Dugotrajni organski zagađivači (POPs)

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    Persistent organic pollutants (POPs) are ubiquitous in all environmental media. Because of their persistence, they are present even in regions where they haven't been released before. POPs are toxic even in very low concentrations, many of them being carcinogenic. Basic representatives and groups of POPs, sources in the environment, ways of transport and elimination, impact to the human health and the environment are presented in this article. At the end Stockholm Convention is mentioned, an international legally binding agreement on persistent organic pollutants.Dugotrajni organski zagađivači (persistent organic pollutants - POPs) su jedinjenja široko rasprostranjena u svim medijima životne sredine. Zbog svoje dugotrajnosti nepromenjeni prelaze velike razdaljine, usled čega se javljaju i u regionima u kojima nikad nisu bili ispuštani. Toksični su u vrlo malim koncentracijama, a mnogi od njih su kancerogeni. U članku su pobrojani osnovni predstavnici i grupe, predstavljeni su izvori emitovanja u životnu sredinu, načini transporta i eliminacije, uticaj na životnu sredinu i zdravlje. Na kraju je kratak prikaz Stokholmske konvencije, međunarodnog dokumenta nastalog radi regulacije POPs-ova

    Use of honeybees (Apis mellifera L.) as bioindicators of spatial variations and origin determination of metal pollution in Serbia

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    Honeybees have been proposed and used as bioindicators for the last few decades, because of their nature. Until now they have mostly been used to determine the present pollution and to distinguish the differences between the sampling locations and the sampling periods. With the use of multivariate statistical methods honeybees can also be used to distinguish the origin of this pollution. In this study the concentrations of Al, Ba, Ca, Cd, Co, Cr, Cu, Fe, Mg, Mn, Na, Ni, Sr and Zn were measured in the bodies of adult honeybees collected from nine different apiaries in Serbia. With the help of the statistical methods it was established that the least polluted area was the one that has no industrial activities or the intense traffic nearby. The most polluted was the urban region, followed by a region close to thermal power plants and ash disposal site. Using PCA and CA the origin of the analyzed metals were proposed. It was suggested that Al, Ba, Ca, Cd, Co, Cr, Cu, Fe, Mn and Ni have anthropogenic origin mainly from the intensive agriculture, traffic and coal combustion.Supplementary material: [http://cherry.chem.bg.ac.rs/handle/123456789/3312

    Ostracism - a powerful tool of constitutional protection in the Athenian polis or a measure with no significant effect?

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    Rad se bavi institutom ostracizma istražujući razloge njegova nastanka, svrhu koja se njime željela postići te značaj koji je imao za razvoj atenskog polisa i njegovu veličinu. Pri tome polazi od pitanja je li ostracizam bio moćno sredstvo zaštite atenskog ustava, jedna od uspješnijih reformskih mjera, oruđe jačanja osobnih moći trenutnih vođa ili tek sredstvo rješavanja nekih kriznih situacija u društvu. Prikaz okolnosti njegova donošenja, načina funkcioniranja te posljedica koje je imao za pojedine atenske građane i polis u cjelini potvrđuje da se radi o dobro osmišljenom institutu koji se kretao u granicama dovoljno širokim da se može lako primijeniti u slučaju potrebe, a istovremeno dovoljno određenim da se ne može zloupotrebljavati. Činjenica da je za ostraciranje pojedinca volja demosa bila nezaobilazna i da se ne može govoriti o velikom broju ostraciranih potvrđuje pak da je demosu bilo stalo do njegovih istaknutih i časnih građana te da je do odluke o tome treba li netko napustiti Atenu dolazilo iznimno, sa spoznajom o tome što polis dobiva, a što gubi. Iz toga treba zaključiti da su Atenjani bili svjesni opasnosti koju je ovaj institut u sebi nosio, ali i njegovih dobrih strana koje su štitile atenski predak. Nije slučajno što se kraj primjene ovog instituta poklapa s vremenom kada je atenska demokracija počela gubiti zanos. On je imao svoj smisao dok je demosu bilo stalo.This paper deals with the institute of ostracism by exploring the reasons for its occurrence, the purpose that it was supposed to attain and the significance it had to the development of the Athenian polis and its size. The starting question is whether ostracism was a powerful tool for the protection of the Athenian constitution, one of the more successful reformative measures, a tool for strengthening personal powers of the current leaders, or merely a means of solving crisis situations in the society. The account of the circumstances of its passing, the way it functioned and the consequences it had for certain citizens of Athens and the polis as a whole confirm that this is a very well-designed institute that operated within wide enough limits that made it easy to apply if the need arose, while remaining specific enough so that it could not be abused. The fact that the will of the demos was a prerequisite for ostracizing an individual and that the number of ostracized people is not large, proves that the demos cared for its distinguished and honourable citizens and that the decision on whether one of them should leave Athens was reached very rarely, with awareness of what was gained and what was lost by the polis. What can be deduced from this is that the citizens of Athens were aware of the dangers inherent to this system, but also of all of its positive sides that protected the social order in Athens. It is not a coincidence that the end of the application of this system coincides with the time when democracy in Athens started to lose its momentum. Ostracism made sense while the demos cared

    Teški metali u zemljištu Beograda

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    The main goal of our work was to determine heavy metal content (Pb, Cd, Zn Cu, Ni, Cr, Hg & As) at different soil depths (5, 10 and 50 cm) in the metropolitan area of Belgrade. The analysis was performed during several years, but our results cover only 2006. Sample selection covered areas near heavy traffic streets and urban parks. Taking in account our results (for the year 2006) and the results acquired from the Public health institute (PHI) of Belgrade (for the years 2003, 2004 and 2005), both obtained by EPA 3050b method, it was quite obvious that our results, that are associated to the depth of 5 cm, have shown that the concentrations of Pb, Zn and Cu are greater then those obtained by PHI. At the same time it could be assumed that the mobility of heavy metals from shallow to deeper depths was limited. The results for Pb (obtained in 2006) and Ni (obtained in 2003, 2005), excide the maximal aloud concentrations (MAC) set by Serbian guideline values for maximal allowed concentrations of dangerous substances in soil and irrigation waters.Usled intenzivnog tehnološkog i industrijskog razvoja u životnu sredinu na razne načine dospevaju velike količine štetnih i toksičnih sup-stanci. Među ovim supstancama značajan je udeo teških metala koji zbog svoje neuništivosti, toksičnosti i biogeohemijskog kruženja predstavljaju veliki problem za životnu sredinu. Industrija, industrijski i komunalni otpad, sagorevanje fosilnih goriva (ugalj, nafta) u industriji, saobraćaju i domaćinstvima najčešći su izvori zagađenja životne sredine teškim metalima i drugim elementima u tragovima. U današnjim uslovima ugroženost zemljišta u Beogradu je velika, a posebna opasnost preti od akcidenata koji se često dešavaju, industrije, saobraćaja, kao i sve većeg broja malih privrednih preduzeća sa značajnom količinom otpada koji predstavlja jedan od glavnih izvora zagađenja zemljišta
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