Wyniki wyszukiwania - Biblioteka Nauki

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Influence of zeolites, humic acids, and selenates (VI) on lead and cadmium immobilization and selected soil properties

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Badora A.

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nr 4

EN

In order to immobilize heavy metals, sorbents that meet the following three criteria can be used: 1) they are non-toxic 2) they cannot make the physicochemical properties of soil worse, and even improve them 3) they have an immobilizing and specific impact on heavy metals. This study compares the influence of mineral and organic sorbents, as well as the presence of selenates (VI), on limiting lead toxicity in a soil. The investigations have also focused on evaluating the effects of these sorbents on select physicochemical and chemical properties of studied soil material collected during the two- year strict pot experiment. Achieved results indicate greater affinity of lead to mineral rather than organic sorbents, although it has depended on zealot and humic acid rates, as well as on physicochemical properties such as soil acidity or soil sorption capacity. Sodium selenate (VI) affected the mobilization of Pb' ions in the pot experiment and the effect was probably associated with subsoil pH changes and excessive doses of the sorbent used in the experiments. The study also has aimed at evaluating soil conditions, under which cadmium toxicity appears, as well as at presenting the possibilities of reducing their activities through the use of unconventional immobilizing agents such as zeolites, humic acids, and selenates (VI). The immobilization of Cd2 ions has been affected both by zeolites and humic acids, but only when applied at lower rates. The influences of cadmium mobilization and immobilization on changes in Cd:Zn and Fe:Mn ratios in soil also have been indicated. Clinoptilolit has appeared to be a promising binding agent for immobilizing the cadmium ions. Applying the selenium compounds has given hope as well, because the element is more often considered as required for living. However, the selenium action mechanism is complicated and not uniform, which needs to be further examined.

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Selenium as a sulphydrylic group inductor in plants

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Hawrylak B. , Szymanska M.

Cellular and Molecular Biology Letters

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2004

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tom 09

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nr 2

EN

We investigated the effect of selenium form and dose on the total glutathione and non-protein -SH group contents in the edible spinach (Spinacia oleracea L.) and ground tomato (Lycopersicon esculentum Mill.) plants. Our experiments were carried out in a hydroponic culture. Selenium was added to the culture medium in its selenite (Na2SeO3 x 5H2O) and selenate (Na2SeO4) forms. Regardless of the selenium form, we observed an increase in the non-protein thiol content. The non-protein -SH group content depended on the form and dose of selenium as well as on the organ and plant species. Regardless of the selenium form, a higher content of non-protein -SH groups were found in the spinach biomass than in the tomato biomass. Selenite contributed to a larger accumulation of non-protein -SH groups in the roots, whereas selenate contributed to their accumulation in the shoots

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Effect of Cd-Se interference on cadmium and selenium bioaccumulation in pea seedlings

80%

Śkopíková A. , Král’ová K. , Masarovičová E.

Proceedings of ECOpole

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2008

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tom Vol. 2, No. 1

135--139

EN

Effect of three cadmium compounds (CdSeO4, CdSeO3 and Cd(NCSe)2(nia)2) containing Se in different oxidation states were used for experiments. Pea seedlings (cv. Felix) cultivated in hydroponic solutions under control conditions were treated with the above-mentioned compounds for two weeks (c = 3÷120 µmol dm-3). Then root and shoot dry mass was estimated and the concentrations of Cd and Se in plant organs were determined using AAS. Bioaccumulation factors related to both investigated elements (Cd, Se) as well as translocation factors were evaluated. Higher compound concentrations were toxic and desiccation of the shoots was observed. Cd concentration in the roots reached higher levels than in the shoots and accumulated Cd amount in plant organs increased with increasing Cd concentration. Whereas treatment with CdSeO3 and Cd(NCSe)2(nia)2) resulted in expressively higher Se concentration in roots, for CdSeO4 treatment Se concentration in shoots exceeded Se concentration in the roots. Therefore treatment with CdSeO4resulted in much higher mobility of Cd and Se within the plants than the treatment with CdSeO3 and Cd(NCSe)2(nia)2).

PL

W eksperymencie wykorzystano trzy związki kadmu (CdSeO4, CdSeO3, Cd(NCSe)2(nia)2) zawierające Se w rożnych stopniach utlenienia. Wschody grochu uprawiane w wodzie w warunkach laboratoryjnych były traktowane wymienionymi związkami przez dwa tygodnie (c = 3÷120 µmol-dm-3). Następnie w próbkach korzeni i pędów roślin oznaczano stężenia Cd i Se z pomocą AAS. Dokonano oceny bioakumulacji i czynników wpływających na przemieszczanie się badanych pierwiastków. Większe stężenie związków były toksyczne i powodowały wysuszenie pędów roślin. Stężenia Cd w korzeniach były większe niż w pędach roślin, a stężenie zakumulowanego Cd w organach rośliny zwiększało się wraz ze wzrostem stężenia Cd. Podczas działania CdSeO3, Cd(NCSe)2(nia)2wyniki wyraźnie wskazywały, że stężenie Se w korzeniach wzrosło, podczas działania związkiem CdSeO4 stężenie Se w pędach było większe od stężenia Se w korzeniach. Zatem w wyniku działania CdSeO4 ma miejsce większa kumulacja Cd i Se w roślinie niż podczas działania związkami CdSeO3 i CdSeO3, Cd(NCSe)2(nia)2.

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