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The toxicity of different selenium forms and compounds – Review
33-38Views:1268Selenium (Se) is an unusual metalloid of considerable interest from both a toxicological and a nutritional perspective, with a very narrow safe range of intake. Although there are many reports about its detoxification properties, toxicity aspects of it have also been tracked for several decades. Lots of studies demonstrated that low Se is an efficacious avail whereas high Se can induce toxicity and the significant toxicity of selenium emphasizes the need to assess the health risk of various selenocompounds as nutritional supplements. The toxicity of different forms and compounds of selenium is also summarized in this review.
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Management of phytopathogens by application of green nanobiotechnology: Emerging trends and challenges
15-22Views:251Nanotechnology is highly interdisciplinary and important research area in modern science. The use of nanomaterials offer major advantages due to their unique size, shape and significantly improved physical, chemical, biological and antimicrobial properties. Physicochemical and antimicrobial properties of metal nanoparticles have received much attention of researchers. There are different methods i.e. chemical, physical and biological for synthesis of nanoparticles. Chemical and physical methods have some limitations, and therefore, biological methods are needed to develop environment-friendly synthesis of nanoparticles. Moreover, biological method for the production of nanoparticles is simpler than chemical method as biological agents secrete large amount of enzymes, which reduce metals and can be responsible for the synthesis and capping on nanoparticles.
Biological systems for nanoparticle synthesis include plants, fungi, bacteria, yeasts, and actinomycetes. Many plant species including Opuntia ficus-indica, Azardirachta indica, Lawsonia inermis, Triticum aestivum, Hydrilla verticillata, Citrus medica, Catharanthus roseus, Avena sativa, etc., bacteria, such as Bacillus subtilis, Sulfate-Reducing Bacteria, Pseudomonas stutzeri, Lactobacillus sp., Klebsiella aerogenes, Torulopsis sp., and fungi, like Fusarium spp. Aspergillus spp., Verticillium spp., Saccharomyces cerevisae MKY3, Phoma spp. etc. have been exploited for the synthesis of different nanoparticles. Among all biological systems, fungi have been found to be more efficient system for synthesis of metal nanoparticles as they are easy to grow, produce more biomass and secret many enzymes. We proposed the term myconanotechnology (myco = fungi, nanotechnology = the creation and exploitation of materials in the size range of 1–100 nm). Myconanotechnology is the interface between mycology and nanotechnology, and is an exciting new applied interdisciplinary science that may have considerable potential, partly due to the wide range and diversity of fungi.
Nanotechnology is the promising tool to improve agricultural productivity though delivery of genes and drug molecules to target sites at cellular levels, genetic improvement, and nano-array based gene-technologies for gene expressions in plants and also use of nanoparticles-based gene transfer for breeding of varieties resistant to different pathogens and pests. The nanoparticles like copper (Cu), silver (Ag), titanium (Ti) and chitosan have shown their potential as novel antimicrobials for the management of pathogenic microorganisms affecting agricultural crops. Different experiments confirmed that fungal hyphae and conidial germination of pathogenic fungi are significantly inhibited by copper nanoparticles. The nanotechnologies can be used for the disease detection and also for its management. The progress in development of nano-herbicides, nano-fungicides and nano-pesticides will open up new avenues in the field of management of plant pathogens. The use of different nanoparticles in agriculture will increase productivity of crop. It is the necessity of time to use nanotechnology in agriculture with extensive experimental trials. However, there are challenges particularly the toxicity, which is not a big issue as compared to fungicides and pesticides.
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Effect of Copper, Zinc and Lead and Their Combinations on the Germination Capacity of Two Cereals
39-42Views:427The majority of researchers have studied the following group of microelements: B, Zn, Mn, Cu, Na, Co, Mo, I, Sn, Cl, Al, V, F, Cr, Hg, Cs, Li, Cd, As, Th, Rb, Cr, W, Ti, Sn, Se, Ba, Br. Sporadically, the following elements have been mentioned too: Au, Ra, Hg and Pb. In this study, the effects of copper treatments and their combination with zinc and lead microelements on the germination of maize and barley were investigated using different concentrations of these microelements. Six treatments were used: 1. Copper-sulphate (CuSO4) applied alone, 2. Zinc-sulphate (ZnSO4) applied alone, 3. Copper applied with zinc, 4. Lead-nitrate (Pb(NO3)2) applied alone, 5. Copper applied with lead and 6. Untreated control. Maize (Kiskun SC 297) and barley caryopsis were treated with copper and zinc solutions in the following concentrations: 0.03%, 0.003% and 0.0003%. Maize and barley caryopsis were treated with these solutions for 12 and 24 hours. Maize and barley caryopsis were also treated with lead solutions Pb(NO3)2 with different concentrations: 0.0005%, 0.005% and 0.05%. Maize and barley were treated with these solutions for 12 and 24 hours. In the combined treatments (3 and 5), the same concentration was used for each microelement as in treatments 1, 2 and 4. Control treatments were treated with water for both plant species. Our results showed that copper microelements significantly inhibit germination compared to the untreated control. The toxicity of copper is higher if concentration increases. Zinc microelements also inhibit germination, however its effect highly depends on the microelement concentration. Treatments of copper + zinc also inhibit germination. The two microelements applied together cause more phytotoxicity than they do alone. Lead is highly toxic to plants even in low concentrations. The toxic effect on germination dramatically increased when lead was applied with copper.
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Utilization and examination of red, elemental selenium nano spheres, produced by fermentation technology, in animal tests
245-247Views:108In our experiments we tested the toxicity of Nano-Se and LactoMicroSel® compared with other organic and inorganic selenium forms, in case of a subakut animal test. We produced the Nano-Se and LactoMicroSel® by probiotic lactic acid bacteria in our laboratory. (Prokisch et al., 2010; Eszenyi et al., 2011). We mixed the inorganic selenium forms, selenite and selenate, the organic form, Sel-Plex® and our products, Nano-Se and LactoMicroSel® into the standard food of laboratory mice and we fed them for two consecutive weeks. After the extermination we observed mortality, the change of body mass,and measured the blood antioxidant capacity with FRAP method.
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Heavy Metals in Agricultural Soils
85-89Views:69The soil constitutes the basis of the food chain. To keep soil conditions in a good trim is very important, it’s part of the sustainable development and of producing food supply harmless to health.
In some cases, soil productivity is the only important part, qualitative requirements or economical characteristics can improve it. The soil is threatened by two danger factors: the soil degradation and the soil pollution. The accumulation of different harmful and/or toxic substances in the soil is well known. Heavy metals constitute a part of it. Metals in the soil and in the soil-solution are balanced. This balance depends on the type of the metal, on the pH, on the cation-band capacity of the soil, on the redox relations and the concentration of cations in the soil.
To be able to handle the metal contamination of the soil, it is important to estimate the form, the possible extension and the concentration of metals.
Of course, the different types of soils have different physical-chemical, biological and buffer capacity, they can moderate or reinforce the harmful effects of heavy metals. To draw general conclusion of the dispersion and quantitative relations on the metals originated from different contamination sources is hard, because in some emissive sources contamination is limited in small areas but on a high level, some others usually expand on larger areas, and as a result of equal dispersion, the contamination’s level is lower.
Heavy metals – unlike alkali ions – strongly bond to organic materials, or infiltrate in a kelát form. Their outstanding characteristic is the tendency to create metal-complex forms. Kelats take part in the uptaking and transportation of heavy metals. Heavy metals exert their effects mostly as enzyme-activators.
The metals cannot degrade in an organic way, they accumulate in living organisms, and they can form toxic compounds through biochemical reactions.
Lot of the heavy metals accumulate on the boundaries of the abiotic systems (air/soil, water/sediment), when physical or chemical parameters change, and this influences their remobilization.
Human activity plays a great part in heavy metal mobilization, results in the human origin of most biochemical process of metals.
To understand the toxic influence of accumulated metals of high concentration, their transportation from soils to plants or their damage in human health, must clearly defined and investigated.
For effective protection against soil pollution, the types and levels of harmful pollution to soil must identified, regarding legal, technical and soil-science aspects, preferable in a single way. Difficulties in this area mean that toxicity depends on loading, uptake, soil characteristics and living organisms (species, age, condition etc.), furthermore, local and economic conditions considerably differ. -
Optimization of inductively coupled plasma mass spectrometer parameter’s to measuring arsenic and selenium
59-64Views:159In the last decades an increased interest has been evolved about arsenic and selenium. The aim is to understand the environmental, agricultural and biological role of the these elements. In case of arsenic the mayor reasons are the relatively high concentration of arsenic in marine biota (mg kg-1) and the arsenic contaminated drinking waterbases of some Asian countries besides Hungary. The toxicity of higher level selenium content is also known, nevertheless selenium is essential for some biological functions. Considering its esssentiality, in our country the insufficient selenium intake rate couse lack of selenium. Measuring the concentrations of these elements are cruital but not satisfactory information, but the speciation, that is the form of an element presented in a sample is also required.
In both cases the most suitable method to determine concentration is the inductively coupled plasma mass spectrimetry. My objective was to optimase the changeable parameters of the ICP-MS for reaching the lowest (the best) detection limit. For this porpuse I have investigated the effect of parameter change on nett signal intensity and relative signal intensity. With the optimased parameter settings the limit of detection for arsenic and selenium were determined, which are 0,032 ng cm-3 for arsenic, and 0,097 ng cm-3 for
selenium. -
Assessment of Environmental Susceptibility/Vulnerability of Soils
62-74Views:86Soils represent a considerable part of the natural resources of Hungary. Consequently, rational land use and proper soil management – to guarantee normal soil functions – are important elements of sustainable (agricultural) development, having special importance both in the national economy and in environment protection.
The main soil functions in the biosphere are as follows: conditionally renewable natural resource; reactor, transformer and integrator of the combined influences of other natural resources (solar radiation, atmosphere, surface and subsurface waters, biological resources), place of „sphere-interactions”; medium for biomass production, primary food-source of the biosphere; storage of heat, water and plant nutrients; natural filter and detoxication system, which may prevent the deeper geological formations and the subsurface waters from various pollutants; high capacity buffer medium, which may prevent or moderate the unfavourable consequences of various environmental stresses; significant gene-reservoir, an important element of biodiversity.
Society utilizes these functions in different ways (rate, method, efficiency) throughout history, depending on the given natural conditions and socio-economic circumstances. In many cases the character of the particular functions was not properly taken into consideration during the utilization of soil resources, and the misguided management resulted in their over-exploitation, decreasing efficiency of one or more soil functions, and – over a certain limit – serious environmental deterioration.
Soil resources are threatened by the following environmental stresses:
– soil degradation processes;
– extreme moisture regime;
– nutrient stresses (deficiency or toxicity);
– environmental pollution.
Environmental stresses caused by natural factors or human activities represent an increasing ecological threat to the biosphere, as well as a socio-economic risk for sustainable development, including rational land use and soil management.
The stresses are caused by the integrated impacts of various soil properties, which are the results of soil processes (mass and energy regimes, abiotic and biotic transport and transformation and their interactions) under the combined influences of soil forming factors. Consequently, the control of soil processes is a great challenge and the main task of soil science and soil management in sustainable development.
The efficient control of these processes necessitates the following consecutive steps:
• registration of facts and consequences (information on land and soil characteristics, land use, cropping pattern, applied agrotechnics, yields, with their spatial and temporal variability);
• evaluation of potential reasons (definition and quantification of soil processes, analysis of influencing factors and their mechanisms);
• assessment of the theoretical, real, rational and economic possibilities for the control of soil processes (including their risk-assessment and impact analysis);
• elaboration of efficient technologies for the „best” control alternatives (best management practice).
Scientifically based planning and implementation of sustainable land use and rational soil management to ensure desirable soil functions, without any undesirable environmental side-effects, require adequate soil information. In the last years such data were organized into a computer-based GIS soil database in Hungary, giving opportunities for the quantification, analysis, modelling and forecasting of the studied environmental stresses and for the efficient and scientifically based prevention, elimination or reduction of environmental stresses and their unfavourable ecological and economical consequences.
Special attention was paid to the assessment of various soil degradation processes, as: (1) soil erosion by water or wind; (2) soil acidification; (3) salinization and/or alkalization; (4) physical degradation (structure destruction, compaction); (5) extreme moisture regime: drought sensitivity and waterlogging hazard; (6) biological degradation; (7) unfavourable changes in the plant nutrient regime; (8) decrease of natural buffering capacity, (9) soil (and water) pollution.
The actions against undesirable environmental stresses and their unfavourable consequences are important elements of sustainable, efficient, economically viable, socially acceptable and environmentally sound crop production and agricultural development. These are joint tasks of the state, decision makers on various levels, the land owners, the land users and – to a certain extent – of each member of the society. -
Parameter optimization of an inductively coupled plasma mass spectrometer for measuring arsenic and selenium
81-85Views:143In the last decades, an increased interest has evolved in arsenic and selenium. The aim is to understand the environmental, agricultural and biological roles of these elements. In the case of arsenic, the major reasons are the relatively high concentration of arsenic in marine biota (mg kg-1) and the arsenic contaminated drinking water bases of some Asian countries, as well as Hungary. The toxicity of higher level selenium content is also known; nevertheless, selenium is essential for several biological functions. Considering its essentialness, in our country, the insufficient selenium intake rate causes a lack of selenium. Measuring the concentrations of these elements provides crucial, but unsatisfactory information, as the speciation, i.e. the form of an element presented in a sample is also required.
In both cases, the most suitable method to determine concentration is inductively coupled plasma mass spectrometry (ICP-MS). Our objective was to optimize the variable parameters of the ICP-MS to attain the lowest (the best) detection limit. For this purpose, we investigated the effect of parameter change on net signal intensity and relative signal intensity. With the optimized parameter settings, the limits of detection for arsenic and selenium were determined, which are 0,032 ng dm-3 for arsenic, and 0,097 ng dm-3 for selenium. -
Selenium speciation analysis of selenium-enriched food sprouts
23-28Views:183In this present study, we prepared selenium-enriched pea and wheat sprouts. During our research we aimed not only to measure the total selenium content of the sprouts but to identify different selenium species.
Scientifical researches show why the analytical examination of different selenium (Se) species is necessary: consumption of all kind of Se-species is useful for a person who suffers in selenium deficit, while there is significant difference between effects of different Se-species on person, in whose body the Se-level is just satisfactory. Biological availability, capitalization, accumulation, toxicity of Se-species are different, but the main difference was manifested in the anti-cancer effect of selenium.
During our research selenium was used in form of sodium selenite and sodium selenate, the concentration of the solutions used for germination was 10 mg dm-3. Control treatment meant germination in distilled water. Total selenium content of sprout samples was measured after microwave digestion by inductively coupled plasma mass spectrometry (ICP-MS). Different extraction solvents were applied during sample preparation in order to separate different Se-species (0.1 M and 0.2 M HCl or 10 mM citric acid buffer). We wanted the following question to be answered: Which extraction solvent resulted the best extraction efficiency? Selenium speciation analysis of sprout sample extracts was performed by high performance liquid chromatography with anion exchange column, detection of selenium species was performed by ICP-MS.
Evaluating our experimental results we have been found that significant amount of selenium of inorganic forms used during germination transformed into organic selenium compounds. There was difference between the amount of Se-species in pea and wheat sprouts and selenium uptake and repartition of selenium species were depended on Se-form used during germination. In addition the chromatogram analysis made us clear as well, that the citric acid solvent proved to be the most effective extraction solvent during sample preparation int he view of organic Se species.
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Risk effects of the spread route of mycotoxins
90-95Views:89In Hungary the mycotoxin is a great problem, because there are many natural toxins in wheat and maize. These cereals can be found on
considerable proportion of the country’s sowing area, and they are deterministic food for the population. The direct human and animal
utilization of the contaminated cereals mean a serious risk in the food chain. In Hungary’s climate the soil is contaminated with pathogen
moulds, particularly Fusarium species, which increase by respective temperature and moisture content in cereals. The Fusarium can
decrease the quality of the wheat in different ways: decrease the germination capability and cause visible discoloration and appearance of
mould, reduces the dry material and nutrient content of the grain. From the toxins produced by the Fusarium genus, the trichotecene (T-2,
HT-2, deoxinivalenol, nivalenol, diacetoxyscxirpenol, Fusarenon-X) and the estrogenic zearalenon (F-2) are the most common in Hungary.
The fumonisins (FB1, FB2, FB3) first identified in 1988, relatively newly discovered, are also important. Major proportion of mycotoxins in a
healthy organization is metabolized by the enzyme system of liver and intestinal bacteria. The toxicity is reduced or even leaves off.
However, more toxic and biologically active compounds can be formed. For the reduction of mycotoxin-contamination several possibilities
are available in the case of storage, processing and feeding. -
GC-MS studies to map mechanistic aspects of photolytic decomposition of pesticides
11-16Views:78Transformation of pesticides in the environment is a highly complex process affected by different factors. Both biological and physical-chemical factors may play a role in the degradation, whose ratio depends on the actual environmental conditions.
Our study aims to reveal specific details of photolytic degradation of pesticides as important soil contaminants. Significance of these studies is enhanced by the fact that pesticide decomposition may contribute to soil degradation, and have harmful biological effects by degrading to toxic products. The toxicity of the examined pesticides is well known, however very little information is available regarding their natural degradation processes, the quality, structure and biological impact of the degradation products.
The photolytic degradation of frequently applied pesticides of distinctive types (acetochlor – acetanilide, simazine – triazine, chlorpyrifos – organophosphate, carbendazim – benzimidazole) was investigated. A special, immerseable UV-light source was applied in order to carry out photodegradation. The degradation processes were followed by thin layer chromatography (TLC) and mass spectrometry coupled with gas chromatography (GC/MS). EI mass spectrometry was used to identify the degradation species.
Each of the studied pesticides underwent photolytic decomposition, and the detailed mechanism of photolytic transformation was established. At least four degradation species were detected and identified in each case. Loss of alkyl, alkyloxy, amino-alkyl and chloro groups might be regarded as typical decomposition patterns. Deamination occurred at the last stage of decomposition. -
Aflatoxin production on agricultural products
67-71Views:139Aflatoxins due to their toxicity pose significant economic and human health threat; therefore, it is important to avoid this type of contamination in agricultural products. Until now significant aflatoxin contamination occurred mainly in foods of tropical and subtropical origin because the optimal growth of the producer Aspergillus species is between 32–38 ºC. Nowadays the aflatoxin contamination is becoming higher threat in Hungary, due to the imported products, the rising average temperature and the climatic changes. There is a significant knowledge on the genetic and environmental effectors of the aflatoxin production; however, it is remained a great problem to control mold contamination and toxin production in farming and stock-raising. Here we attempted to summarize the knowledge on aflatoxin production and attempts of the elimination.
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A simple method for preparing elemental selenium nano- coating inside a silicone surface
35-43Views:205Selenium nanoparticles (SeNPs) with a bright red colour have aroused worldwide attention due to their unique properties in selenium supplementation because of their low toxicity and favourable bioavailability. A simple method was developed for making a red selenium nanolayer on the inner surface of Polyvinyl chloride (PVC) and silicone tube. The selenium nanoparticles were produced by the reaction of sodium selenite and ascorbic acid. Red amorphous selenium nanoparticles have been successfully synthesized by the reaction of 500 mg dm-3 Se (sodium selenite) solution with 10 g dm-3 ascorbic acid solution at room temperature, and morphology was confirmed by X-ray diffraction analysis (XRD). The coating density was compared on PVC and silicone surfaces by using Scanning Electron Microscopy (SEM) and Energy-dispersive X-ray (EDS) analysis. The nanolayer with about 16 µm thickness on the silicone surface significantly evenly distributed compared to the PVC surface. The selenium coated silicone tube could be a good source of selenium for a continuous, low-level selenium supplementation of farm animals via drinking water.
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The importance of selenium in the living world and in the scientific research
278-286Views:137Presently, selenium (Se) is one of the most investigated microelements. It has an important proven role in many vital processes. Directly or indirectly, selenium deficiency can play a role in the development of many diseases. On the other hand, the concentration range in which selenium is essential is narrow; there is a narrow gap between necessary and toxic content in dietary intake. In this context, selenium contamination poses a further health risk for people if they live near the industrial areas and mining activity.
In this paper, we comprehensively introduce the very important trace element selenium. We studied the base parameters, deposit, analytic and deficiencies, problem of contamination and also the solution of contamination problems of selenium. -
The synthesis of selenium nаnоpаrtiсle (SeNPs) – Review
5-8Views:355Selenium is an important dietary miсrоnutriеnt required for the nоrmаl physiоlоgy and mеtаbоlism of humans and аnimаls. The biоlоgicаl prоperties оf selenium nаnо pаrticle depend оn their size аnd fоrms. Sеlenium nаnоpаrticle (SeNPs) аttrасts еvеn mоrе аttеntiоn, thanks to its high biоаvаilаbility аnd muсh lоwеr tохiсity thаn inоrgаniс аnd оrgаniс fоrms. In this review, I summаrized the infоrmаtiоn аnd wаys оf prоductiоn оf selenium nаnоpаrticle. SeNPs hаve been prоduced in chemicаl, physicаl, аnd biоlоgicаl wаys. In recent years, biоlоgicаl wаys hаve been especially important in the prоductiоn оf selenium nanoparticles.
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The effect of gossypol acetate on the fertility of boars
47-55Views:121This study evaluated the effect of gossypol acetate, a potential antifertility compound, on semen quality and testicular histopathology of boars. Six boars were allotted into two experimental groups. Half of the animals were fed a diet that was supplemented with 2 mg of gossypol acetate per kg body weight per day for 9 weeks, control animals received a gossypol acetate-free feed. During the experimental period, semen was collected weekly from each boar and semen parameters were recorded. The animals were then euthanized, testicular samples were collected and histopathological examination of the testicular cells, as well as morphometrical analysis of the seminiferous tubules, were performed. The percentage of spermatozoa showing tail abnormalities increased significantly (P=0.017) in the semen of boars fed gossypol acetate-supplemented feed, while several other semen parameters deteriorated without showing statistical significance. Gossypol acetate supplementation also led to a decrease (P=0.042) in the number of spermatogonia in the seminiferous tubules and an increase (P=0.020) in the number of vacuoles in the seminiferous epithelium, consistent with changes seen in cases of male reproductive toxicity. In conclusion, gossypol acetate negatively affected a number of semen characteristics and also had detrimental effects on the histopathology of the testes.
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The Role and Significance of Soil Analyses in Plant Nutrition and Environmental Protection
3-8Views:80Hungary has a rich history of soil analyses and soil mapping. Our main tasks today are the preservation of soil fertility as well as balancing the goals of production and environmental protection. The main requirement of agricultural production is to adapt to ecological and economic conditions.
In a series of consultative meetings in the past seven years, representatives from Central and Eastern Europe have analyzed nutrient management practices in their respective countries. According to a joint memorandum agreed upon in 2000, in the countries awaiting accession, the quantity of nutrients used per hectare is considerably smaller than the Western-European usage targeted through special subsidies. The current low nutrient usage contradicts the principles of sustainability and that of the efficient use of resources, jeopardizing soil fertility.
In Hungary, the use of inorganic fertilizers underwent a dynamic development, which manifested itself in an almost tenfold usage growth between 1960 and 1985. This growth slowed down somewhat between 1985 and 1990 and then reduced dramatically after 1990, reaching record lows at the usage levels of the 60s. The nutrient supply has had a negative balance for the last 15 years.
The increasing and then decreasing usage trends can equally be detected in the domestic yield averages of wheat and corn as well as in the nutrient supply of soils. Yields were the largest when usage levels were the highest, and decreased thereafter. Draughts have also contributed to smaller yields. The dramatic decrease in the use of inorganic fertilizers when adequate organic fertilizers are lacking endangers our soils’ fertility.
About 50% of soils in Hungary are acidic. Acidity is mostly determined by soil formation, but especially on soils with a low buffering capacity, this acidity may intensify due to inorganic fertilizers. Sustainable agriculture requires the chemical improvement of acidic soils. According to their y1 values, the majority of our acidic soils need to be improved. This chemical soil remediation is required in 15% of the acidic soils, while it’s recommended for another 20% of these soils.
Results of the analyses conducted in the framework of the soil-monitoring system set up in Hungary in 1992 show that in 95% of the analyzed samples, the toxic element content is below the allowable limit. Cultivated areas are not contaminated; toxicity above the legal level was found only in specific high-risk sampling areas: in the vicinity of industry, due to local overload. The basic principle of sustainable agriculture is to preserve soil fertility without undue strain on the environment. The intensity of the production needs to be considered according to the conditions of the site; i.e.; nutrient management needs to be site-specific. It is recommended to differentiate three types of cultivated land in terms of environmental sensitivity: areas with favorable conditions, endangered areas, and protected areas, and then to adopt nutrient management practices accordingly. To meet all the above-mentioned goals is impossible without systematic soil analysis. Tests conducted by the national monitoring system cannot replace regular field measurements. -
Changes in toxic elements content of soil after sewage sludge treatment in energy willow plantation
7-10Views:116The primary purpose of our experiment was the solution of municipal excess sludge treatment by a renewable energy resource used willow (Salix viminalis L.) plantation. Tests were carried out to state whether the applied sewage sludge has caused any accumulation of the toxic elements in the studied soil layers, and - based on the results –to see whether the plantation is suitable for the treatment of municipal sewage sludge.
The excess sludge (sludge before dewatering) is beneficial for the willow, because it contains a 3–5% dry matter and therefore, a lot of water, too. This high water content ensures the high water amount needed for the intensive growth of the willow. On the other hand, the wastewater treatment plant can save the dewatering cost which corresponds to about 30% of the water treatment process costs. The amounts of the sprinkled sewage sludge were calculated on the basis of its total nitrogen content. Treatments were the followings: control, 170 N kg ha-1 year-1 and 250 N kg ha-1 year-1. The mean values of the toxic element concentrations in the sewage sludge did not cross the permitted limits of the land accommodating.The measured toxic element values of the soil were compared to the limits of the 50/2001. (IV.3.) Government Regulation.The sprinkled sewage sludge on the bases of the total N content did not cause accumulation of heavy metals in the soil and the treated plants were also healthy without any signs of toxicity.
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Effect of arsenic treatments on physiological parameters of sunflower and maize plants
81-84Views:155The environment is contaminated with heavy metals and other toxic compounds. One of the most important toxic element is the arsenic (As).
The objective of our study was to investigate the effect of As on fresh and dry weight of sunflower and maize in the early growth phases.
Seedlings were grown in climate room on nutrient solution which were treated with 3, 10 and 30 mg kg-1 arsenic. The plants were treated separately with As(III) and As(V). After 14 day, changes in fresh and dry weight of maize shoots and roots were recorded. In the case of sunflower these parameters were measured after 21 day.
The applied As(III) and As(V) decreased the fresh and dry mass of the shoots and roots of seedlings, especially at concentration 30 mg kg-1. We can draw the conclusion that the treatments of the maize and sunflower roots with arsenic had negative effects on the biomass accumulation. We found that the sunflower plants are more sensitive to arsenic toxicity than maize plants, and all data demonstrate that the As(III) is more toxic to these plants than the As(V).