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Comparative studies to model bioavailability of pesticides in distinctive soil types
17-23Views:97Bioavailability of pesticides is determined by two major factors: soil characteristics and pesticides’ chemical feature. These factors result in a definite adsorption capability whose extent varies on a large scale. By revealing interactions between pesticides and soils it is of high interest to model bioavailability of widely used pesticides, as it is a key element in terms of prospective toxicological aspects. Our work signifies steps forward improving pesticide soil mobility prediction models as we created model systems representing correctly natural relations. Comparison of different solvent extraction methods proved to be an efficient tool to gain information on the bioavailability of some widely used pesticides as well as to model actual environmental processes.
Comprehensive comparison has been made between different experimental methods by applying 5 extraction models showing diverse efficiency in extracting capability of pesticides. In some cases chloroform excelled in mobilizing pesticides from soil, however mostly application of humic acid solution as extraction model was found to be at least as efficient as methanol, chloroform or CaCl2-solution.
Four chemically much different pesticide (simazine, acetochlor, chlorpyrifos and diuron) were applied to two soil types (both sandy and brown forest). The extracted amounts were determined by GC/MS technique. Adsorption coefficients (Kd) were also calculated for the examined samples.
Obtained results for Kd indicated that chemical feature of pesticides seemed to be of utmost importance in terms of soil binding capability preceding the relevance of soil characteristics. Adsorption capability of chlorpyrifos proved to be the most pronounced preceding simazine and the least prone to bind to soil acetochlor and diuron -
Modern approaches to assessment of PAHs bioavailability in soil for environmental toxicology research
35-36Views:119The efficiency of TENAX beads sorption method enabling to separate the bioavailable fraction of PAHs in the soil has been estimated. Due to the method the PAHs effects on soil biota have been explored. Laboratory investigations have ascertained possibility of application of TENAX beads sorption for soil quality assessment.
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Spatial Relationships Between pH and Vegetation Pattern in an Area Contaminated with Heavy Metals
140-143Views:102It is not possible to gain information on the risk factor representing the bioavailability and the mobility of the contaminants only on the basis of their total concentrations. Especially, in case of heavy metals, which can be charaterised with very different chemical forms and their mobil and mobilizable parts are determined by complex balances highly sensitive to the changing environmental conditions. Considering mine tailings, however, the toxic elements are basically in ore forms having low adsorption capacity, thus the heavy metal ion concentration in solution is governed mainly by the pH conditions. In Gyöngyösoroszi, the spatial distribution of the total heavy metal concentrations as well as that of pH values determining the bioavailable part of the toxic elements were estimated and by mapping the vegetation pattern, relationship was analysed among the total Zn, Cu, Pb and As concentrations, the pH and the species present. Results show that the presence of the certain plant species is highly determined by the pH on the mine tailing material, the highest vegetation density was found where the bioavailability of the toxic elements were considered the smallest as a result of the neutral pH. As a result, high diversity could be found even in places where the total zinc, copper, lead and arsenic concentrations were extreme. In addition, plant species could be identified, which are tolerant to toxic elements and present even if the pH is low and the bioavailable part of the heavy metals is relatively high.
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Harnessing diversity in durum wheat (Triticum turgidum L.) to enhance climate resilience and micronutrient concentration through genetic and agronomic biofortification
9-20Views:241Huge consumption of wheat-driven food products with low bioavailability and small concentrations of zinc is responsible for zinc-induced malnutrition and associated health complications. The contemporary durum wheat varieties have inherently tiny zinc concentrations in developing grain, which cannot meet the daily human zinc demand. Despite the fact that over two billion people are suffering from iron and zinc-induced malnutrition, various intervention measures have been deployed to reverse the effect of zinc-induced malnutrition on humans. There are evidences that agronomic and genetic biofortification approaches can increase grain yield and nutritional quality (i.e. zinc, iron, protein, and vitamins) of durum wheat to a greater extent. However, there is a lack of direct empirical evidence for which the influence of both biofortification approaches on improving human health. Application of micronutrient-containing fertilizers either in the soil or foliarly is effective in combination with NPK, organic fertilizers coupled with efficient durum wheat varieties, emphasizing the need for integrated soil fertility management (ISFM). Although genetic biofortification is a cost-effective and sustainable approach, agronomic biofortification provides an immediate and effective route to enhancing micronutrient concentrations in durum wheat grain. The application of zinc-containing fertilizers is more effective under drought conditions than in normal growing situations. Hence, this article provides a key information for agronomists and breeders about the potential of biofortification interventions to improve durum wheat yield and enrich the grain qualitative traits to ensure food and nutritional security of the ever-increasing world population.
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Assessment and comparison of selenium-enriched maize with sodium selenite and sodium selenate
11-15Views:195Selenium is an element of environmental interest owing to the narrow range between its nutritionally required and toxic concentrations in many organisms. Its mobility and bioavailability differ greatly depending on individual Se species. In this regard, in present study, the uptake and distribution of Se, the changes in Se content, and the effects of different concentration of Se in two forms of sodium selenite and sodium selenate on maize plants were measured in nutrient solution experiments to clarify their response to the two forms of Se. The results revealed that the Se content in shoots and roots of maize plants significantly increased as the Se level increased. Two Se forms behaved differently and the effects of toxic damage in samples which had been treated with selenite were much more than in the selenate treatments.
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A simple method for preparing elemental selenium nano- coating inside a silicone surface
35-43Views:274Selenium 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.