Changes in Soil Properties Under the Influence of Microplastics in Plastic and Open Field Production in Three Serbian Valleys

Crop production in plastic greenhouses is one of the major sources of plastic pollution worldwide. The main hypothesis of this study is that the regular use of mulch film in greenhouses leads to the cumulative accumulation of microplastic particles (MPs) in the soil, which ultimately leads to changes in the soil properties. Therefore, the main objective of this study was to identify the possible changes in the physical, chemical, and biological properties of soil in greenhouses in three regions of Serbia. The following chemical parameters were determined: electrical conductivity, soil acidity, cation exchange capacity (CEC), total carbon (TC) and nitrogen (TN) content, plant-available phosphorus and potassium content, and trace element content. The following physical parameters were determined: particle size distribution, volumetric mass, specific mass, and porosity; the biological parameters that were determined were microbial respiration and labile carbon. The obtained data were processed using network analysis (NA) to identify the complex relationships between MP content and soil parameters. The NA results support the main findings that the presence of microplastics leads to the destruction of soil structure, which reduces bulk density and increases soil porosity. A strong positive correlation of MPs with soil particles < 0.02 mm and a negative correlation with CEC were found. In the Danube Valley, soil respiration was 78% higher in the open ground compared to a plastic greenhouse. The results contribute to a better understanding of the influence of MPs on soil properties and its ecological functions

Degradation of fluoroquinolone antibiotic levofloxacin by UV-induced ferric ion photolysis in aqueous medium: the role of pH and chelation

The increased use of fluoroquinolone antibiotic levofloxacin (LVX) contributes to its significant presence as a pollutant in water and soil environments and the consequent need for developing efficient water processing methods for its degradation and removal. The understanding of coordination and photo-chemistry of LVX in the presence of ferric ions enables potential improvements of iron-based advanced oxidation processes (AOPs) for wastewater treatment. Herein, the pH-dependence of LVX chelation with ferric ions was investigated by UV–Vis and fluorescence spectroscopy at pH 2, pH 5, and pH 7. The results obtained for examined pHs showed pH 5 as optimal for forming LVX-Fe3+ complex. The formation of LVX-Fe3+ complex makes coordinated LVX more susceptible to oxidation. Photosensitivity of LVX and LVX/Fe3+ system to UV irradiation was examined at acidic pHs, using UV–Vis spectroscopy and HPLC analysis. In acidic aqueous solutions, LVX remains unchanged after UV irradiation, while the presence of ferric ions promotes its UV-induced photodegradation. The investigated UV/Fe(III)-based AOP for degradation of LVX showed the best performance at pH 5 in the presence of Fe3+ ions in excess due to LVX-Fe3+ complex formation and sufficient amount of Fe3+–OH− species available for photolysis and production of OH• radical

Biocontrol of Seedborne Fungi on Small-Grained Cereals Using Bacillus halotolerans Strain B33

The development of biological pesticides is rapidly becoming an integral aspect of pest management in sustainable agriculture. This study was conducted to evaluate the effectiveness of Bacillus halotolerans strain B33 against three common seedborne fungal pathogens—Fusarium graminearum, Alternaria alternata, and Aspergillus flavus. B33 strain identity was determined using the 16S rRNA and tuf gene sequences. Commercial wheat, barley, oat, and rye seeds were artificially infected by fungal isolates and then treated with B33 overnight culture in Nutrient Broth. The obtained results indicate high efficacy against F. graminearum (83.55–94.38%) and A. alternata (85.05–96.70%), whereby the highest efficacy was noted on wheat seed and the lowest was detected on rye seed. On the other hand, B33 achieved 100% efficacy against A. flavus on barley, rye, and oat seeds, while being 96.24% effective against this pathogen on wheat. Principal component analysis indicated the highest treatment influence on A. flavus. The effect of all tested treatments on seed germination was statistically significant compared to the controls, whereby the number of germinated seeds declined as the seed infection rate increased. B. halotolerans strain B33 effectively managed seedborne fungal pathogens, thereby enhancing seed germination

Natural Sunlight Driven Photocatalytic Degradation of Methylene Blue and Rhodamine B over Nanocrystalline Zn2SnO4/SnO2

The natural sunlight driven photocatalytic degradation of organic pollutants is a sustainable solution for water purification. The use of heterojunction nanocomposites in this process shows promise for improved photodegradation efficiency. In this work, nanocrystalline Zn2SnO4/SnO2 obtained by the solid-state synthesis method was tested as a heterojunction photocatalyst material for the degradation of methylene blue (MB) and Rhodamine B (RhB) dyes as single and multicomponent systems in natural sunlight. Characterization of the structure and morphology of the synthesized nanocomposite using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) combined with energy dispersive X-ray spectroscopy (EDS), and photoluminescence (PL) spectroscopy confirmed the formation of Zn2SnO4/SnO2 and heterojunctions between Zn2SnO4 and the SnO2 nanoparticles. A photodegradation efficiency of 99.1% was achieved in 120 min with 50 mg of the photocatalyst for the degradation of MB and 70.6% for the degradation of RhB under the same conditions. In the multicomponent system, the degradation efficiency of 97.9% for MB and 53.2% for RhB was obtained with only 15 mg of the photocatalyst. The degradation of MB occurred through N-demethylation and the formation of azure intermediates and degradation of RhB occurred through sequential deethylation and fragmentation of the xanthene ring, both in single and multicomponent systems

Reconstruction of the enigmatic pre-Variscan paleogeographic configuration of the western peri-Moesian realm (Carpathian-Balkans, eastern Serbia): An insight into Devonian small-scale continental and paleo-oceanic units

The Carpathian-Balkans provide insight into how two distinct but limited-sized north Gondwanan ribbon-shaped paleocontinents interacted prior to the Variscan Devonian collisional onset: (i) the drifted “Carpathian-Balkan microcontinent” (Serbo-Macedonian/Supragetic/Getic(Kučaj)) and (ii) the already amalgamated Avalonian Danubian-Moesian basement fragment with its Devonian suture elements. These two crustal fragments were separated by the intervening Rheic Ocean during the Devonian. Despite the investigated eastern Variscan collisional assembly being stacked near the overprinted promontory of the East European Craton, its sliced basement segments and their Devonian record are well exposed in eastern Serbia. The synthesis reveals that the sliced Carpathian-Balkan inliers play a crucial role in understanding the lithospheric-scale movement of smaller continental terranes from north Gondwana and their suturing modes related to the surrounding Paleozoic oceans. An analysis of geochemical, paleogeographic, and regional geological data reveals that continental and oceanic paleoenvironments existed prior to and during the Devonian period, merging with the already amalgamated Danubian block and the Moesian microplate. Nonetheless, despite the well-preserved Devonian record found in eastern Serbia, the Romanian South Carpathians, and western Bulgaria, only a limited number of reconstructions clarify the pre-Variscan tectono-paleogeographic setting. After a few rift-drift cycles connecting north Gondwana and southern Laurussia, the tectonic transport of Cadomian to Cenerian peripheral terranes from northern Gondwana begun with the post-Ordovician rifting off. The rifting led to the formation of narrow, elongated crustal segments. The outboard Lower Paleozoic ribbon-shaped paleocontinent, including its Carpathian-Balkan continental fragment, occupied a position between two principal Paleozoic oceans. On the southern flank of the exotic narrow Lower Paleozoic microcontinent, we demonstrate for the first time the presence of a continental extension of Devonian age, likely associated with the adjacent Paleotethyan Ocean. The synthesis further demonstrates that the volcano-sedimentary protoliths of Devonian-aged greenschist facies rocks, which traverse the continental Serbo-Macedonian/Supragetic/Getic Devonian microcontinent, serve as markers of Early Devonian (back-arc) rifting. On its opposite Eurasian flank towards Danubian/Moesia, following the accumulation of Silurian–Early Devonian deep-water sediments, the Kučaj(Getic) turbidites, along with the expanding Middle to Late Devonian oceanic crust (Danubian ophiolites), belonged to the Rheic Ocean. The geochemical modeling of Devonian ophiolites reveals that this Balkan-Carpathian ocean displays both mid-ocean ridge basaltic (Tisoviţa Iuţi, Deli Jovan) and volcanic arc/back-arc signatures (Zaglavak, Tcherni Vrah). The extracted petrographic and regional geological constraints confirm the short transport of eroded material from the eroded Serbo-Macedonian/Supragetic narrow elongated landmass into the Late Devonian (Carboniferous) Kučaj(Getic) trench turbidites. Geochemical signatures outline the intraoceanic character of this frontal pre-Variscan subduction-driven active margin. The proposed new Devonian reconstruction updates the existing paleogeographic constraints on the opposite Avalonian block, revealing that the narrow Devonian ocean and its subduction beneath the Avalonian “micro-terranes” (Danubian/Moesia) produced an epicontinental basin with Devonian volcanism assigned to the Hanseatic-type rifting off processes

Convergent evidence for the temperature- dependent emergence of silici cation in terrestrial plants

Research on silicon (Si) biogeochemistry and its beneficial effects for plants has received significant attention over several decades, but the reasons for the emergence of high-Si plants remain unclear. Here, we combine experimentation, eld studies and analysis of existing databases to test the role of temperature on the expression and emergence of silicification in terrestrial plants. We first show that Si is beneficial for rice under high temperature (40 °C), but harmful under low temperature (0 °C), whilst a 2 °C increase results in a 37% increase in leaf Si concentrations. We then find that, globally, the average distribution temperature of high-Si plant clades is 1.2 °C higher than that of low-Si clades. Across China, leaf Si concentrations increase with temperature in high-Si plants (wheat and rice), but not in low-Si plants (weeping willow and winter jasmine). From an evolutionary perspective, 77% of high-Si families (>10 mg Si g−1 DW) originate during warming episodes, while 86% of low-Si families (<1 mg Si g−1 DW) originate during cooling episodes. On average, Earth’s temperature during the emergence of high-Si families is 3 °C higher than that of low-Si families. Taken together, our evidence suggests that plant Si variation is closely related to global and long-term climate change

An Estimate of Penetration Depth of Rigid Rods Through Materials Susceptible to Microcracking: Part 1 - Theory

The present study proposes an approximate model focused on a simplified estimate of depth of penetration of rigid projectiles into quasibrittle solids. Penetration at normal incidence of a slender, rigid rod into massive targets, made of materials predisposed to microcracking due to their inferior tensile strength and heterogeneous structure, is an event characterized by a high level of aleatory variability and epistemic uncertainty. This inherent stochasticity is incorporated into a model developed based on particle dynamics simulations that provide the key modeling ingredient – an estimate of the radial traction necessary to dynamically expand a cylindrical cavity. The penetration depth expressions are derived for the conical and ogive nose projectiles. The related theoretical considerations for spherical nose projectiles are developed to the point where using the cylindrical cavity approximation becomes debatable. The novel use of the power-law radial traction dependence upon the expansion rate yields equations of penetration resistance and penetration depth defined in terms of hypergeometric functions. These expressions are readily evaluated by modern tools for technical computing

Modified Z-scheme heterojunction of TiO2/polypyrrole recyclable photocatalyst

A straightforward physical mixing method was used to prepare the highly efficient TiO2/polypyrrole (PPy) photocatalysts of hydrothermally prepared TiO2 and PPy, obtained by the chemical oxidative polymerization, with different amounts of PPy (0, 0.5, 1, 1.5, 3, and 5 wt.%). Synthesized composites were characterized by XRPD, FTIR, FESEM, EDS, BET, and UV–Vis methods, while their photocatalytic activity was estimated towards the degradation of toxic dye Reactive Orange 16 (RO16) based on UV–Vis and TOC. XRPD showed that the TiO2 was obtained as nanoanatase with crystallites of 26 nm. Band gap energies of the nanocomposites decreased with the PPy content increase from 3.11(3) to 2.94(3) eV. The TiO2/1%PPy demonstrated the highest photocatalytic activity by completely degrading RO16 for 120 min under simulated solar light with degradation described by the pseudo-first reaction order with the rate constant of 0.056(5) min−1. It was established that 73% of the total reactive oxidative species were h+ and that the photodegradation mechanism followed a slightly modified direct Z-scheme in which PPy played an active and irreplaceable role by opening a new reaction path. Besides extremely high photocatalytic efficiency, the recyclability of TiO2/1%PPy was confirmed since no decrease in efficiency was found after several runs of photocatalysis

Temperature and frequency tuned study of electrical properties of M-type strontium hexaferrite

Strontium hexaferrite (SrFe12O19) nanoparticles were prepared by the green sol-gel auto combustion method with mandarin orange peel extract acting as the reducing/chelating agent and combustion fuel. X-ray diffraction analysis confirmed the formation of an M-type magnetoplumbite phase consisting of randomly oriented hexagonal crystallite platelets 38 nm thick and 47 nm wide. The dielectric, conductivity, and impedance metrics were examined in the frequency range of 8 Hz to 5 MHz with temperature variation from 20 to 55 oC. The dielectric constant and loss decreased with frequency increment in conjunction with the Maxwell-Wagner model. An increase in temperature caused activation and accumulation of activated charge carriers at grain boundaries enhancing polarization and increasing dielectric parameters in the low-frequency region. Cole-Cole plots for electrical modulus revealed the role of both grain and grain boundaries behind the charge transport phenomenon. Increase in temperature activated the charge carriers and reduced the relaxation time. The variation of electrical parameters of grains/grain boundary aligned with simulated values derived from the equivalent circuit model. The Jonscher power law governed polaron hopping through the correlated barrier hopping model of the conduction. The Kohlrausch, Williams, and Watts function demonstrated non-Debye relaxation for peaks observed in the imaginary part of the electric modulus. Both the real and imaginary parts of complex impedance decreased with the rise in temperature due to thermal agitation of charge carriers and their release, while increasing SrFe12O19 conductivity. The grain and grain boundary resistances reduced from 6.52 Mohm to 3.80 M, 55.59 to 7.33 Mohm, respectively, while the grain boundary capacitance increased from 74.14 to 130.45 pF in the temperature range 20 - 55 oC

Assessment of the ecological status of five water supply reservoirs based on the fish community

Cilj ovog istraživanja bio је da se uporedi status i kvalitet vode u akumulacijama Gruža, Garaši, Stubo-Rovni, Ribnica i Brestovac, na osnovu kvalitativnog i kvantitaivnog sastava riblje zajednice. Ustanovljeno je prisustvo 17 vrsta iz devet familija. Najveći broj vrsta zabeležen je u akumulaciji Gruža, a najmanji u akumulaciji Stubo-Rovni. Vode svih ispitivanih akumulacija pripadaju polisaprobnim vodama, osim Gruže koja pripada β mezosaprobnim vodama II klase boniteta. Akumulacije Gruža, Garaši i Ribnica imale su kvalitet vode koji spada u II-III klasu, dok je kod akumulacija Stubo-Rovni i Brestovac zabeležena III-IV klasa. Kvalitet vode u ispitivanim akumulacijama nije na zadovoljavajućem nivou.This study aimed to compare the status and water quality (WQ) in five reservoirs (Gruža, Garaša, Stubo-Rovni, Ribnica, Brestovac) based on the qualitative and quantitative composition of the fish community. The presence of 17 species from nine families was established. The greatest number of species was recorded in Gruža, and the lowest in Stubo-Rovni. The waters of all reservoirs belong to polysaprobic waters, except for Gruža, which belongs to β-mesosaprobic waters of class II. Gruža, Garaši and Ribnica had WQ that belongs to class II-III, while in Stubo-Rovni and Brestovac class III-IV was recorded. The WQ in the studied reservoirs is unsatisfactory