Konstruktionselemente

Vetter, Max

doi:10.1007/978-3-663-05742-0_2

Cited by 2 publications

(2 citation statements)

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“…The lichen, Usnea barbota, found at forest canopy level in Sri Lanka, is reported to accumulate arsenic from the atmosphere (49) with a concentration of 134 ng/g, six times greater than other species in the forest. High concentrations of arsenic have also been found in a number of mushrooms (50)(51)(52)(53). Dandelion, Taraxacum officinale, growing around smelters in Bulgaria has concentrations of As up to 16 μg/g (54).…”

Section: Uptake Of Arsenic By Plantsmentioning

confidence: 99%

Uptake of Arsenic by Plants in Southwest England

Farago¹,

Kavanagh²,

Leite³

et al. 2002

ACS Symposium Series

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The literature concerning arsenic in soils and plants is reviewed briefly. The uptake of arsenic by a number of plants that colonize sites, contaminated by arsenic from past mining and smelting activities, is described. Plants growing on soil with high As were stunted and displayed a red coloration. Armeria martima operates an exclusion mechanism, with low root/soil concentration ratios. Uptake of arsenic from soil in Calluna vulgaris and Agrostis tenuis show weak correlations with Fe in soil and soil pH. The relative accumulation (leaf/soil ratio) of As in Calluna at one site plotted against soil concentration approximated to a hyberbolic curve.The sources of naturally occurring arsenic in the environment are primary minerals including arsenopyrite (FeAsS), orpiment (As 2 S 3 ), realgar (As 4 S 4 ) and secondary minerals of arsenic (1,2). The geochemistry of arsenic has recently been reviewed (3-5), including estimates of the arsenic global cycle (5).Arsenic concentrations in uncontaminated soils have been reported in the range 0.1-40 μg/g worldwide (6,7) with an average of 5-6 μg/g (8) and 5-100 μg/g for the UK (9). High concentrations in soils, relative to these values, can occur in many areas; these arise from (4): naturally occurring arsenic-rich minerals and rocks, such as pyrite; waste materials resulting from mining and smelting activities; the burning of arsenic-rich coal; arsenic-containing agrochemicals (10), and organoarsenic-based warfare agents (//).Depending on pH and Eh, arsenic is present in soils as As(III) or As(V) (2). Microbial activity within the soil gives rise to a number of reactions, including methylation, demethylation, oxidation and reduction (2). Under aerobic conditions arsenate(V) is precipitated as ferric arsenate in horizons rich in iron. Both As(III) and As(V) complex with hydrous oxides of Fe, Mn and Al (12, 13). The sorption of As by hydrous iron oxides occurs both in acid and in alkaline soils, whereas sorption by hydrous oxides of Al is reported to be important only in acidic soils (14)(15)(16). Under reducing sulfidic conditions, As(III) associates with metal sulfides, sulfidic minerals being formed under extreme reducing conditions. Clay minerals and organic ligands can also influence the species of arsenic present in soil.Many authors have sought to discover the species of arsenic present in soil, the leachability and the potential bioavailability of arsenic to biota, including post-ingestion bioavailability to humans. Arsenic-bearing phases in soils and waste materials have been characterized using electron microprobe analysis (EMPA) (17) and extended X-ray absorption fine-structure spectroscopy (EXAFS) (18). Single (19) and sequential (20-25), extraction schemes have been developed leading to operationally determined associations between arsenic oxyanions and other soil constituents, many based on the similar chemistry of As and Ρ (26,27). The introduction of chromatographic separation coupled with inductively coupled plasma -mass spectrometry (ICP-MS) has lead to the i...

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Section: Uptake Of Arsenic By Plantsmentioning

confidence: 99%

Uptake of Arsenic by Plants in Southwest England

Farago¹,

Kavanagh²,

Leite³

et al. 2002

ACS Symposium Series

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“…This is the most widely produced mushroom of the world (4 million tons per year). There has been a growing interest in this mushroom for the past few years [19]. The study of Spolar et al proved that the consumption of Se-enriched Agaricus bisporus is an effective means of retarding the growth of chemically induced tumors [20].…”

Section: Introductionmentioning

confidence: 99%

Improving selenium extraction by sequential enzymatic processes for Se-speciation of selenium-enriched Agaricus bisporus

2001

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Sample preparation methods based on the use of proteolytic and cell wall digesting enzymes for the speciation analysis of selenized mushroom were investigated. The sample (Agaricus bisporus; 160 microg total Se per g sample) was grown on compost supplemented with selenized yeast. Experiments were carried out to elucidate the possible role of the cell wall digesting enzymes--Lysing enzyme and Driselase--in the improvement of extraction efficiency with and without inhibiting proteolysis during cell wall digestion. A 3-step procedure applying Lysing enzyme and pronase gave the highest extraction efficiency (89%); however, the best species recovery was achieved by a one-step proteolytic procedure. All the procedures of selenium speciation were controlled by independent ICP-AES analysis measuring the total amount of selenium.

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Konstruktionselemente

Cited by 2 publications

References 0 publications

Uptake of Arsenic by Plants in Southwest England

Uptake of Arsenic by Plants in Southwest England

Improving selenium extraction by sequential enzymatic processes for Se-speciation of selenium-enriched Agaricus bisporus

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