UTJECAJ ONEČIŠĆENOSTI TLA TEŠKIM METALIMA NA KLONOVE TOPOLA IZ SRBIJE

Oxidative stress is known as disturbed balance between antioxidative protection mechanism and production of reactive oxygen species, which can negatively influence on normal biological and metabolical processes in living organisms, such as poplar species. Phytoremediation is promising biotechnical method of cleaning of polluted soils by various pollutants: heavy metals, organic contaminants, pesticides, oil etc. Until today, poplars showed potential for regenerating polluted soils during phytoremediation process. This study represents results of oxidative stress profiles of three poplar clones (M1, B229 and PE 19/66) shoots from Institute of Lowland Forestry and Environment, University of Novi Sad, Serbia, while being treated by different concentration of three heavy metals in soil: Ni3+, Cu2+ and Cd2+. Biochemical parameters of oxidative stress which have been analyzed were: content of soluble proteins, intensity of lipid peroxidation, antioxidative capacity by ferric reducing antioxidative power assay and activity of superoxid dismutase. Results showed that the most acceptable phytoremediation response to heavy metal pollution in soil showed clone M1. Great differences between B229 and PE 19/66 clones were in response on soil heavy metal contamination, directly suggesting of not being suitable for possible phytoremediation application.Oksidacijski stres je poznat kao narušena ravnoteža između antioksidacijskog mehanizma zaštite i proizvodnje reaktivnih kisikovih vrsta, što može negativno utjecati na normalne biološke i metaboličke procese u živim organizmima, kao na primjer kod topola. U cilju opstanka, aerobni organizmi su stekli mehanizme antioksidacijske zaštite, gdje su od enzimskih najistraženije aktivnosti antioksidativnih enzima kao što su katalaze, peroksidaze, glutation peroksidaze i superoksid dismutaza. Fitoremedijacija je obećavajuća biotehnička metoda čišćenja zagađenih tala raznim onečišćujućim tvarima poput: teških kovina, organskih kontaminanata, pesticida i dr. Do danas, topole su pokazale potencijal za regeneraciju onečišćenih tala tijekom fitoremedijacijskog procesa.Biokemijsko profiliranje statusa oksidacijskog stresa u drvenastim biljkama nije često istraživana u Srbiji i stoga je cilj ovoga pokusa bio ispitati utjecaj različitih koncentracija tri jona teških kovina, Ni3+, Cu2+ i Cd2+ na razinu oksidacijskog stresa tri klona, dvije različite vrste topole (Populus euramericana-M1; PE 19/66 i B-229 oba Populus deltoides vrsta). Biokemijski parametri za određivanje razine oksidacijskog stresa su: lipidna peroksi­dacija (LPx), test redukcijske snage željeza (FRAP), superoksid dismutaze (SOD) aktivnost i sadržina topivih bjelančevina. Ovi rezultati mogli bi dati smjernice u odabiru klonova iz kolekcije Instituta za nizijsko šumarstvo i životnu sredinu Univerziteta u Novom Sadu za buduće fitoremedijacijske uporabe ovih genotipova topola. Pješčano fluvisol tlo u pokusnim posudama je zagađeno različitim tretmanima teških kovina, koji su prikazani u tablici 1. Biljni ekstrakti izrađeni su od 2 g biljnog materijala (izbojci) i homogenizirani s kvarcnim pijeskom i suspenzirani u 10 cm3 0,1 mol/dm3 K2HPO4 pH 7,0. Homogenati su centrifugirani za 10 min na 4000 g (Quy Hai sur., 1975). Sva očitavanja apsorbancija za sadržaj topivih proteina, SOD i FRAP odrađeno pomoću Janway UV / VIS spektrofotometra 6505 i za čitanje količine nastalog MDA korišten je višefrekvencijski Spectrum Termo Corporation.Sve analize izvedene su u tri ponavljanja. Statistička usporedba između uzoraka izvedena je u programu Statistica 9, koristeći Duncan test, s statističkom značajnosti p <0,05. Dobiveni rezultati prikazani su grafički preko histograma (slike 1. do 4.) i iznad njih su slova koja označuju statistički značajne razlike između rezultata i kontrola (od a do e).Usporedni postotak je izračunat prema formuli: Δ (%) = (100 * uzorak / kontrola) –100, gdje vrijednosti mogu rezultirati pozitivno (+) ako je došlo do povećanja u odnosu na kontrolu i rezultiralo negativno (–), ako je došlo do smanjenja u odnosu na kontrolu.Trudić i sur. (2012) analizirali su kroz iste metode okdisacijskog stresa ekstrakte lišća i korijena spomenutih klonova topola. Uspoređujući ove rezultate, B229 klon je kroz lišće i korijenje pokazao više prihvatljiv antioksidacijski odgovor, dok je, u ovom istraživanju, M1 klon pokazao najprihvatljivije antioksidacijske odgovore kroz ekstrakte izbojaka. Parametri iz Pilipović i sur. (2012), Trudić i sur. (2012) i naše studije, mogu predstavljati udružen fiziološki i antioksidacijski marker sustav za buduće različite fitoremedijacijske primjene ovih klonova na tlima onečišćenim raznim tvarima.Rezultati ovog istraživanja mogu ukazati na genotipske specifičnosti svih ispitivanih biokemijskih parametara i obilježava klonove topola, kao što je M1 kao primarni, a B229 klon kao potencijalno sljedeći u primjeni fitoremedijacije tala onečišćenih teškim kovinama. Ipak, za stjecanje novih, dubljih rezultata u vezi s oksidacijskim stresom izazvanim onečišćavanjem tala teškim kovinama, potrebne su dalje in vitro antioksidacijske analize

CO2 Emission Factors for Coals

Za izračunavanje emisije ugljikova dioksida zbog izgaranja ugljena, emisijski faktor CO2 važan je ulazni parametar. Referentni emisijski faktori prema Uputama Međuvladinog tijela za klimatske promjene iz 2006. godine (engl. Intergovernmental Panel on Climate Change, IPCC) specificirani su prema stupnju pougljenja (coal rank), ali se pri izradi nacionalnog izvješća o stakleničkim plinovima preporučuje primjena nacionalnih emisijskih faktora. Sadržaj ugljika najvažnije je svojstvo ugljena i pokazatelj je stupnja pougljenja (karbonizacije). Međutim mnoga svojstva ugljena vrlo su specifična (npr. sadržaj sumpora, pepela, vlage i macerala) te emisijski faktori CO2 ugljena ne ovise samo o stupnju pougljenja već i o njegovu geografskom porijeklu. U preliminarnom istraživanju, temeljem podataka dobivenih analizom goriva, izračunati su emisijski faktori CO2 za ugljene i treset s područja Livna, BiH: 147,9 t TJ−1 za treset, 109,5 t TJ−1 za lignit i 98,7 t TJ−1 za smeđi ugljen, što odgovara sljedećim donjim ogrjevnim vrijednostima (Hd): 3,6 MJ kg−1, 11,5MJ kg−1 i 20,6 MJ kg−1. Razlika u ogrjevnoj vrijednosti može se djelomično objasniti različitim udjelom ukupne vlage u ispitivanim uzorcima. Usporedba izračunatih emisijskih faktora s referentnim vrijednostima, pokazala je najveća odstupanja kod treseta (39,5 %), potom kod lignita (8,2 %) i smeđeg ugljena (4,3 %).Emission factors are used in greenhouse gas inventories to estimate emissions from coal combustion. In the absence of direct measures, emissions factors are frequently used as a quick, low cost way to estimate emissions values. Coal combustion has been a major contributor to the CO2 flux into the atmosphere. Nearly all of the fuel carbon (99 %) in coal is converted to CO2 during the combustion process. The carbon content is the most important coal parameter which is the measure of the degree of coalification (coal rank). Coalification is the alteration of vegetation to form peat, succeeded by the transformation of peat through lignite, sub-bituminous, bituminous to anthracite coal. During the geochemical or metamorphic stage, the progressive changes that occur within the coal are an increase in the carbon content and a decrease in the hydrogen and oxygen content resulting in a loss of volatiles. Heterogeneous composition of coal causes variation in CO2 emission from different coals. The IPCC (Intergovernmental Panel on Climate Change) has produced guidelines on how to produce emission inventories which includes emission factors. Although 2006 IPCC Guidelines provided the default values specified according to the rank of the coal, the application of country-specific emission factors was recommended when estimating the national greenhouse gas emissions. This paper discusses the differences between country-specific emission factors and default IPCC CO2 emission factors, EF(CO2), for coals. Also, this study estimated EF(CO2) for two different types of coals and peat from B&H, on the basis fuel analyses. Carbon emission factors for coal mainly depend on the carbon content of the fuel and vary with both rank and geographic origin, which supports the idea of provincial variation of carbon emission factors. Also, various other factors, such as content of sulphur, minerals and macerals play an important role and influence EF(CO2) from coal. Carbonate minerals (calcite and siderite) directly contribute CO2 when they decompose during coal combustion. Variations in the maceral content can also influence CO2 emissions; high inertinite contents increase CO2 emissions. Sulphur in coal reduces EF(CO2). Fuel analysis is very important when estimating greenhouse gas emissions and emission factors. In this preliminary study, based on the results of the fuel analysis, CO2 emission factors for coals and peat from Livno, B&H have been calculated. EF(CO2) is defined as the amount of carbon dioxide emission per unit net calorific values of the fuel. Net calorific value (the lower heating value) corresponds to the heat produced by combustion where total water in the combustion products exists as water vapour. The EF(CO2) obtained for sub-bituminous coal, lignite and peat were: 98.7, 109.5, and 147.9 t TJ−1, respectively, which correspond to the following net calorific values: 20.6, 11.5 and 3.6 MJ kg−1. The heating value is generally known to increase with the increase in carbon content (this parameter is connected with the degree of coalification, coal age). The other indispensable parameters are hydrogen, which has a positive effect on the net calorific value, and oxygen and water which impact the net calorific value negatively. The differences in net calorific values can be explained in part by the difference of total moisture content among the different fuel types. The CO2 emission factors calculated in this study were compared with those of IPCC. A significant difference was observed for peat (39.5 %), followed by lignite (8.2 %) and sub-bituminous coal (4.3 %)

Identification and Perceived Value of Ecosystem Services of Urban Green Areas. Case Study: Kamenički Park in Novi Sad, Serbia

Urban parks, as one of the most significant urban green areas (UGA), bring many direct or indirect benefits, including but not limited to ecosystem services (ES) (Mexia et al. 2018). These services are often generalized, unquantified and poorly supported by empirical evidence and their negative consequences – disservices are rarely mentioned (Roman et al., 2021; Pataki et al., 2011). In order to improve planning, design and management of UGA that can increase their environmental benefits (Xie et al. 2019), better understanding and additional field research of ES and disservices is required. As a result of a survey of employees of the Institute for Nature Conservation of Vojvodina Province that manages the park and on-site users, this study represents a research of the perceived value of generated ES on the example of Kamenički park in Novi Sad, as there are no studies on the actual value of those ES. After identifying major ES, the employees and users evaluated them by their perception on a scale of 1 – the ES is well provided, 2 – service is provided but can be enhanced and 3 – the service is not provided, but has potential. Employees mainly emphasized regulation and supporting services (regulation of air quality, noise reduction, wind protection, maintaining biodiversity), but also cultural services (educational role, recreation and enjoying nature, spiritual peace and prosperity). Users opted mainly for cultural services (recreation and enjoying nature and inspiration for culture, art and design), but also for supporting services like maintaining biodiversity. The specific location, valuable natural and cultural-historical characteristics of Kamenički park contribute to the provision of numerous ES, but also offer the opportunity to develop additional ones that are currently not represented or are not sufficiently provided. The opinions and needs of stakeholders and users regarding ES can be a guideline in planning in accordance with the ES, which is a step to sustainable cities. Quantifying the degree to which various ES are related to plant diversity and structure would provide evidence of the ability to manipulate designed ecosystems to maximize the benefits they provide to urban landscapes (Nighswander et al. 2021)

Chemical parameters of oxidative stress adaptability in beech

e antioxidant activity, lipid peroxidation, and contents of free proline and soluble proteins were investigated on six-year-old beech plants. Provenance Avala, in Serbia, had the best adaptability to environmental factors on locality Fruska Gora due to low lipid peroxidation, high FRAP value, and free proline and soluble proteins contents. Provenances Scharnstein and Mitterndorf, in Austria, had the best adaptability to environmental factors on locality Debeli Lug due to high FRAP value and free proline and soluble proteins contents. FRAP values in majority of provenances from locality Debeli Lug were higher. Correlations parameters were much higher between provenances in locality Debeli Lug, situated at higher altitude, which is the consequence of better adaption to environmental factors in�uence

Biochemical and gene expression analyses in different poplar clones: the selection tools for afforestation of halomorphic environments

Halomorphic soils cover a significant area in the Vojvodina region and represent ecological and economic challenges for agricultural and forestry sectors. In this study, four economically important Serbian poplar clones were compared according to their biochemical and transcriptomic responses towards mild and severe salt stress to select the most tolerant clones for afforestation of halomorphic soils. Three prospective clones of Populus deltoides (Bora-B229, Antonije-182/81 and PE19/66) and one of hybrid genetic background P. nigraxP. deltoides, e.g., P. x euramericana (Pannonia-M1) were hydroponically subjected to NaCl as a salt stress agent in a concentration range from 150 mM to 450 mM. Plant responses were measured at different time periods in the leaves. Biochemical response of poplar clones to salt stress was estimated by tracking several parameters such as different radical scavenging capacities (estimated by DPPH, FRAP and ABTS assays), accumulation of total phenolic content and flavonoids. Furthermore, accumulation of two osmolytes, glycine betaine and proline, were quantified. The genetic difference of those clones has been already shown by single nucleotide polymorphisms (SNPs) but this paper emphasized their differences regarding biochemical and transcriptomic salt stress responses. Five candidate genes, two putative poplar homologues of GRAS family TFs (PtGRAS17 and PtGRAS16), PtDREB2 of DREB family TFs and two abiotic stress-inducible genes (PtP5SC1, PtSOS1), were examined for their expression profiles. Results show that most salt stress-responsive genes were induced in clones M1 and PE19/66, thus showing they can tolerate salt environments with high concentrations and could be efficient in phytoremediation of salt environments. Clone M1 and PE19/66 has ABA-dependent mechanisms expressing the PtP5CS1 gene while clone 182/81 could regulate the expression of the same gene by ABA-independent pathway. To improve salt tolerance in poplar, two putative GRAS/SCL TFs and PtDREB2 gene seem to be promising candidates for genetic engineering of salt-tolerant poplar clones

Modeling a Catalytic Reactor for Hydrotreating of Straight-Run Gas Oil Blended with Fluid Catalytic Cracking Naphtha and Light Cycle Oil: Influence of Vapor-Liquid Equilibrium

Reducing the sulfur content of diesel fuels may require adjusted operation of low-pressure hydrotreater units. A mathematical model for co-hydrotreating of straight run gas oil blended with fluid catalytic cracking naphtha and light cycle oil was developed using an axial distribution of phase equilibrium and effective wetting in the catalytic reactor. The model assumes that hydrodesulfurization (HDS) and hydrodearomatization reactions occur on the catalyst surface which is in contact with the vapor or liquid phase. Kinetic equations of HougenWatson type were used to describe HDS reactions for different classes of sulfur compounds. Model results were validated using the industrial test run data, and very good predictions of overall sulfur conversion and reactor temperature were obtained. Simulations of reactor operation at different pressures, temperatures, and H-2 purities confirm that reaction pressures of around 100 bar and high-purity hydrogen streams are required for almost complete removal of sulfur compounds

Analiza uticaja ovlaženosti katalizatora u industrijskom TBR reaktoru na reakcije hidrodesulfurizacije i hidrodearomatizacije

Many industrial scale trickle bed reactors (TBR) operate at lower liquid superficial velocities ( lt 0.5 cm/s) at which the catalyst particle are not completely wetted. This phenomenon of incomplete wetting has therefore received significant attention and numerous studies have addressed the influence of wetting on the overall rate, conversion/selectivity behavior, and heat effects in TBR. The incomplete wetting conditions correspond to stagnant liquid pockets due to lower liquid superficial velocity which could cause significant influence on reactor performances. In this paper, several models for wetting efficiency in TBR on industrial level are examined and influence on reaction rate and reactor performance is discussed.Mnogi reaktori sa pakovanim slojem katalizatora (TBR) u industrijskim procesima za hidroobradu rade pri malim površinskim brzinama tečne faze ( lt 0,5 cm/s) pri čemu su čestice katalizatora samo delimično ovlažene. Ovaj fenomen delimične ovlaženosti katalizatora detaljno je ispitivan, kao i uticaj stepena ovlaženosti na brzine reakcija koje se odvijaju u procesu, na konverzije, selektivnost, i na porast temperature u reaktoru. U ovom radu upoređeni su rezultati nekoliko različitih modela za izračunavanje ovlaženosti u industrijskom reaktoru sa pakovanim slojem katalizatora, kao i uticaj ovlaženosti na brzine hemijskih reakcija i na rad industrijskog rektora