HYPERACCUMULATION OF CADMIUM IN MAIZE PLANT (Zea Mays)

Maize plant responses, in terms of growth and metal uptake, to different concentrations of cadmium ions (4, 20 µM) were analyzed in a hydroponic culture, for 2 weeks. For a 4 µM cadmium-contaminated environment, the maize plant presents the highest bioaccumulation level after 192 h, with a recovery degree of 52%, meanwhile, at a 20 µM concentration, the highest bioaccumulation was registered after 366 h, with a corresponding recovery degree after 288 h (10.56%). The translocation factor presented higher values for 20 µM induced contamination than for 4 µM, which means that increasing metal concentration in the medium increased the concentration in the upper parts of the plant. Anatomical sections of a maize plant (in a 4 and 20 µM cadmium-contaminated environment) were observed to evidence the changes in plant morphological structure. The efficiency of phytoextraction is related to the metal concentration in the environment and to the plant's ability to grow on polluted soil sites, concomitantly with a high biomass yield. Keywords: heavy metal, phytoremediation, bioaccumulation, translocation factor INTRODUCTION Heavy metal contamination is a serious environmental problem that limits crop production and threatens human health through the food chain. Cadmium, one of the most toxic environmental pollutants for plants, may interfere with numerous biochemical and physiological processes -including photosynthesis, respiration, nitrogen and protein metabolism, and nutrient uptake. Phytoremediation is an in situ nondestructive technique, characterized by the utilization of hyperaccumulator plant species to remove the heavy metals from soil. The suitability of a certain plant for heavy metal remediation is determined by various plant properties, such as heavy metal tolerance, size, growth rate and rooting depth, heavy metal accumulation in aboveground plant parts and climatic adaptation and pest resistance. 1,2 The aim of this research was to evaluate the maize plant responses to cadmium stress conditions, every 48 h, for 2 weeks, and the efficiency in phytoremediation processes. EXPERIMENTAL Maize seeds (Zea mays) were sterilized in the commercial bleaching agent HOCl (1%) for 30 min and rinsed with distilled water under stirring for 10 min, the process being repeated 3 times. The seeds were placed over moist filter paper disks in Petri dishes and stored in the dark at 25 ºC, with a view to their germination. The , 5 µM Fe) with the pH adjusted 3 to 6.8. The plastic pots were covered with an aluminum foil to prevent the development of photosynthetic algae. After 5 days of germination, seedlings of maize with the same size were assembled in each hydroponic unit. The volume of nutrient solution (150 mL) was not modified throughout the experiments, to avoid the variation of metal concentrations. Every 48 h and at the end of the assay (2 weeks), the contents of cadmium in the roots, stem and leaves, as well as the growth parameters of maize plants, were determined. The plant roots were rinsed in abundant tap and distilled water ALINA STINGU et al. 288 before mineralization. Maize plants separated into roots, stems and leaves were oven-dried at 60 ºC, until constant mass was reached, and then the plant tissues were digested 4 using HNO 3 (65%) and H 2 O 2 (30%), on a hot plate at 120 ºC, for at least 5 h. The measurement of the metal content in the solution was accomplished through AAS (using a GBC Avanta 2003 Atomic Absorption Spectrophotometer). To evaluate the growth rate of the maize plant every 48 h, in a cadmium-contaminated environment, the following formula was used: growth rate, % = 100 x (growth parameters at the beginning of the experiment -growth parameters at a considered time)/growth parameters at a considered time. Spectrophotometric quantification of heavy metal concentration in maize plant tissues permitted the evaluation of cadmium bioaccumulation, translocation factor and recovery: Bioaccumulation coefficient = (cadmium concentration µg/g dry plant tissue)/(cadmium concentration µg/mL nutrient solution); 5 Translocation factor (TF) = ratio of metal concentration in shoots/ratio of metal concentration in roots; 6 Recovery, % = metal content in shoot or root/metal content in the medium. 7 At the end of the experiment, histological cross-sections were obtained for maize roots. The sections were cut manually, using microtome and elder pith as a support. The histological sections were washed in sodium hypochlorite, then in acetic acid (to eliminate the cellular content) and distilled water. The sections were coloured with iodine green (1 min), washed in 90% ethylic alcohol and distilled water, then coloured with ruthenium red (1 min) and again washed in distilled water. RESULTS AND DISCUSSION In the first hours, under 4 µM cadmium stress conditions, an increasing trend in plant growth and development was observed, the maximum growth rate being registered at 144 h. 192 h after the beginning of the experiment, the growth process seemed to stop, being resumed after 48 h. For a 20 µM cadmium-contaminated environment, the maximum growth rate was registered in the first 48 h. After 192 h, a decreasing trend in plant growth was observed. Maize plant growth rate decreased with increasing cadmium concentration in the growth medium Cadmium concentration (μg/g dry mass) and content (μg/plant) in maize plant presented different values, as depending on metal contamination level. The highest values for cadmium concentration and content (390.04 μg/plant), under 4 µM stress conditions (15430.99 μg/g), were registered at 192 h. Reported to the 20 µM cadmiumcontaminated environment, the highest metal content (395.82 μg/plant) and concentration (22443.54 μg/g) were recorded at 228 and 336 h. These results could be correlated with the plant growth rat

A bio-based carbon rich material for efficient remediation of environmental hazardous

Spruce bark, a waste from forestry and wood industry, represent a valuable resource. Subjected to biorefinery, this feedstock leads to separation of extractibles and final conversion products. The main final product is biochar, a rich carbon material that could be efficient in environmental remediation. This study assessed the lead uptake capacity of biochar. The total Pb uptake was a quite fast process (120 min), for a sorbent dose of 0.25 g/L and pH 5. The kinetic was properly described by pseudo-second-order model. Further developments are open considering activation/functionalization of biochar as well as other hazardous pollutants and competitors’ uptake

A bio-based carbon rich material for efficient remediation of environmental hazardous

Spruce bark, a waste from forestry and wood industry, represent a valuable resource. Subjected to biorefinery, this feedstock leads to separation of extractibles and final conversion products. The main final product is biochar, a rich carbon material that could be efficient in environmental remediation. This study assessed the lead uptake capacity of biochar. The total Pb uptake was a quite fast process (120 min), for a sorbent dose of 0.25 g/L and pH 5. The kinetic was properly described by pseudo-second-order model. Further developments are open considering activation/functionalization of biochar as well as other hazardous pollutants and competitors’ uptake

Removal of lead (II) from aqueous solution by sorption on natural hemp fibers

The sorption process plays an important role in removing heavy metals such as lead from aqueous environments. In recent years, the applications of low cost sorbents have been widely studied for heavy metal ions removal from wastewaters. Natural materials that are available in large quantities or certain wastes from industrial and agricultural operations have the potential to be used as low cost sorbents, as they represent unused resources, with wide availability and are environmentally friendly. However, the necessity for investigating more and more natural and waste materials is still very important in order to obtain the best material for industrial applications. In this context, natural hemp fibers have been evaluated for Pb (II) sorption from diluted aqueous solutions. In order to establish the optimum conditions, the effect of initial pH of solution, hemp dose, Pb (II) initial concentration, and temperature and contact time of phases on the Pb (II) sorption by natural hemp has been studied. It has been found that in the studied initial pH range of 2- 5, the sorption increases with pH increasing. The values of the Pb (II) sorption percentage increase with increasing hemp dose. The amount of Pb (II) retained on hemp fibers increase with increasing Pb (II) concentration in initial solution, but the sorption percentage decreases. The temperature has a favorable effect within the batch sorption under study. The Pb (II) amounts retained on hemp increase with contact time of phases increasing. The results of this study suggest that natural hemp could be a viable and potential sorbent for the removal of Pb (II) from wastewaters with low content of the tested cation

Cellulose-Based Metallogels—Part 2: Physico-Chemical Properties and Biological Stability

Metallogels represent a class of composite materials in which a metal can be a part of the gel network as a coordinated ion, act as a cross-linker, or be incorporated as metal nanoparticles in the gel matrix. Cellulose is a natural polymer that has a set of beneficial ecological, economic, and other properties that make it sustainable: wide availability, renewability of raw materials, low-cost, biocompatibility, and biodegradability. That is why metallogels based on cellulose hydrogels and additionally enriched with new properties delivered by metals offer exciting opportunities for advanced biomaterials. Cellulosic metallogels can be either transparent or opaque, which is determined by the nature of the raw materials for the hydrogel and the metal content in the metallogel. They also exhibit a variety of colors depending on the type of metal or its compounds. Due to the introduction of metals, the mechanical strength, thermal stability, and swelling ability of cellulosic materials are improved; however, in certain conditions, metal nanoparticles can deteriorate these characteristics. The embedding of metal into the hydrogel generally does not alter the supramolecular structure of the cellulose matrix, but the crystallinity index changes after decoration with metal particles. Metallogels containing silver (0), gold (0), and Zn(II) reveal antimicrobial and antiviral properties; in some cases, promotion of cell activity and proliferation are reported. The pore system of cellulose-based metallogels allows for a prolonged biocidal effect. Thus, the incorporation of metals into cellulose-based gels introduces unique properties and functionalities of this material

A kinyerési módszer befolyása a vadkömény-illóolaj kihozatalára és főkomponenseire: The Effect of Extraction Methods on Caraway Essential Oil Yield and Composition / Influenţa metodelor de extracţie asupra gradului de extracţie şi a componenţilor majori din uleiul volatil de chimen sălbatic

The wild cumin (Carum carvi L.) samples were collected from a little meadow situated in Harghita Mountain (Csíkmadaras, Hargitafürdő), and the harvested was obtained from the market. The essential oil was obtained with Clevenger-type laboratory steam distillation equipment (both, electrically and microwave heated) and with CO2 in supercritical state, using laboratory scale SFT 100 apparatus. The variation in time of the essential oil yield directly, and the main component contents was determined by GC-FID. The highest yield was obtained by hydro-distillation, but the fastest was microwave technique. The microwave pre-treatment and supercritical extraction involves some loss of the essential oils, which influence the ratio of carvone/limonene of the extract.  In case of supercritical extraction the tapping moments and parameters affect both the yield of essential oil and the carvone/limonene ratio, which grow in time. Kivonat A vadkömény (Carum carvi L.) mintákat a Hargita hegység hegyi kaszálóiról (Csíkmadaras, Hargitafürdő) gyűjtöttük, míg a termesztett mintákat a kereskedelemből szereztük be. Az illóolaj kivonást elektromos, valamint mikrohullámú fűtésű Clevenger-típusú laboratóriumi vízgőz-desztillációs berendezéssel, valamint a szuperkritikus állapotú szén-dioxiddal végeztük az SFT 100 készülékben. Az illóolaj hozamot közvetlenül, a fő összetevő tartalmat gáz-kromatográffal határoztuk meg. Legnagyobb hozamot a hidrodesztilláció, a leggyorsabbat a mikrohullámú technika biztosítja. A mikrohullámú előkezelés és szuperkritikus extrakció némi veszteséggel jár az illóolaj kihozatal és a kivonat karvon/limonén arányát illetően. Sszuperkritikus extrakció esetében a lecsapolási paraméter és az idő befolyásolja a hozamot, valamint az illóolaj karvon/limonén arányát, amely növekszik az idő múlásával

Hizb ut-Tahrir in der Presse II : eine Exploration der Unterschiede zwischen akademischen Diskursen und redaktionellen Standpunkten in Europa and Zentralasien

This article analyzes academic discourses on Hizb u-Tahrir ai -Islami (after this HT) in various disciplines, provides an overview of media frames applied to HT in German, British and Kyrgyz quality newspapers, and examines the differences between the conclusions of scholars and mass media representations of HT. The introductory section of the paper briefly presents a group of selected authors and texts, illustrates the importance of drawing parallels between academic and journalistic discourses on HT, and explains the choice of the countries used in the study. The methodological section specifies the questions, sources and methods of research. Finally, there is a detailed presentation and discussion of the findings, followed by a summary of the conclusions

Hizb ut-Tahrir in der Presse II : Eine Exploration der Unterschiede zwischen akademischen Diskursen und redaktionellen Standpunkten in Europa and Zentralasien

Der Aufsatz analysiert den Diskurs über Hizb u-Tahrir al-Islami (HT) in verschiedenen akademischen Disziplinen, gibt einen Überblick über die Medienframes, die in der Berichterstattung über HT in der deutschen, britischen und kirgisischen Qualitätspresse angewendet werden, und untersucht die Unterschiede zwischen der wissenschaftlichen Einschätzung und der Darstellung von HT in den Massenmedien. Der einleitende Abschnitt des Aufsatzes stellt einige ausgewählte Autoren und Texte vor, erläutert die Wichtigkeit des Vergleiches zwischen akademischen und journalistischen Diskursen über HT und begründet die Auswahl der Länder, die in der vorliegenden Studie vertreten sind. Der methodologische Abschnitt beschreibt die Fragestellungen, die verwendeten Quellen und die Methoden der Untersuchung. Schließlich folgt eine detaillierte Darstellung und Diskussion der Untersuchungsergebnisse und eine Zusammenfassung der daraus gezogenen Schlussfolgerungen

Comparative quantitative and qualitative content analyses of coverage of Hizb ut-Tahrir in German, British and Kyrgyz quality newspapers in 2002-2007

This dissertation studies coverage of Hizb ut-Tahrir al Islami, the “Party of Islamic Liberation”, in German, British and Kyrgyz quality newspapers between 2002 and 2007. This Islamist organization is trans-national in its scope of influence and radical in its core ideology. In 2003 HT was banned in Germany for its anti-Semitic slogans and in Kyrgyzstan for instigating inter-ethnic conflicts. However, as of today HT operates legally and maintains its international headquarters in Great Britain. This empirical investigation employs a combination of quantitative and qualitative methods to answer four main research questions: to what extent HT was newsworthy in Germany, Great Britain and Kyrgyzstan between 2002 and 2007; are there any patterns of how different newspapers cover HT in Germany, Great Britain and Kyrgyzstan; is there a difference in how liberal and conservative newspapers cover HT in Germany and Great Britain; and, what images of HT were created in these three countries with words and pictures. The sample consisted of 947 newspaper articles and 87 visual images that appeared in five German (Die Tageszeitung, Frankfurter Rundschau, Süddeutsche Zeitung, Frankfurter Allgemeine Zeitung, Die Welt), five British (The Independent, The Guardian, Financial Times, The Times, The Daily Telegraph) and one Kyrgyz (Vecherniy Bishkek) quality newspapers during 2002-2007