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Titolo:
Selenium and its redox speciation in rainwater from sites of Valparaiso region in Chile, impacted by mining activities of copper ores
Autore:
De Gregori, I; Lobos, MG; Pinochet, H;
Indirizzi:
Univ Catolica Valparaiso, Inst Quim, Valparaiso, Chile Univ Catolica Valparaiso Valparaiso Chile Inst Quim, Valparaiso, Chile
Titolo Testata:
WATER RESEARCH
fascicolo: 1, volume: 36, anno: 2002,
pagine: 115 - 122
SICI:
0043-1354(200201)36:1<115:SAIRSI>2.0.ZU;2-B
Fonte:
ISI
Lingua:
ENG
Soggetto:
HYDRIDE GENERATION; KINETICS; WATERS; SOIL; UK;
Keywords:
selenium; speciation; rainwater; differential pulse cathodic stripping voltammetry; hydride generation-atomic absorption spectrometry; hydride generation-atomic fluorescence spectrometry;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Agriculture,Biology & Environmental Sciences
Citazioni:
29
Recensione:
Indirizzi per estratti:
Indirizzo: De Gregori, I Univ Catolica Valparaiso, Inst Quim, POB 4059, Valparaiso, Chile Univ Catolica Valparaiso POB 4059 Valparaiso Chile , Chile
Citazione:
I. De Gregori et al., "Selenium and its redox speciation in rainwater from sites of Valparaiso region in Chile, impacted by mining activities of copper ores", WATER RES, 36(1), 2002, pp. 115-122

Abstract

The determination of the total concentration of selenium does not provide sufficient information about its toxicity and its bioavailability. The determination of its chemical forms is the basis for understanding the biogeochemical cycle in terrestrial and aquatic ecosystems and for detecting the species which might be toxic to biota. In this work we describe an analyticalprocedure to carry out the redox speciation of selenium present at Ultratrace levels in rainwater from sites of Valparaiso region in Chile, impacted by mining activities of copper ores. A simple preconcentration step of the rainwater sample on a rotavapor system, in vacuum at low temperature permits the concentration of the different redox selenium species until levels quantifiable by sensitive techniques such as differential pulse cathodic stripping voltammetry or by spectrometric techniques, based on the hydride generation and detection by atomic absorption or atomic fluorescence spectrometry. These techniques coupled to redox chemical reactions allow the redox speciation of selenium. The results show that the open evaporation system canbe used to concentrate water samples when the aim of the analysis is the determination of the total selenium concentration. On the contrary, to carryout its redox speciation only the preconcentration. performed on rotavaporsystem, in vacuum can be used. When synthetic solutions containing different redox species of selenium, at ultratrace levels, were slowly evaporated on open system, Se(II) and Se(IV) were oxidized. The optimized procedure was then applied to the selenium determination and its redox speciation in rainwater samples collected in sites impacted by mining activities of copper ores. It was found that the amounts of total selenium in rainwater, as copper, from Puchuncavi valley decrease exponentially with the distance from the source, indicating that these elements in this region arise from the industrial complex Las Ventanas. In the redox speciation of selenium, Se(IV) and Se(VI) were the species found in all rainwater samples analyzed, providing selenium in species which are most favorable for their uptake by the vegetation grown in these soils. (C) 2001 Elsevier Science Ltd. All rights reserved.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 30/03/20 alle ore 09:10:45