O arsênio (As) é um elemento não essencial ao homem, encontrado na natureza nas formas inorgânicas (As-i) e orgânicas (As-o). As espécies inorgânicas, arsenito e arsenato (As3+ e As5+), são as mais tóxicas, podendo interferir em reações bioquímicas, estado redox das células, formação de trifosfato de adenosina (ATP) e gerar danos oxidativos, ocasionando proliferação celular e câncer. O As-i pode sofrer metilação no organismo e no ambiente, gerando metabólitos que são menos reativos com componentes do tecido e mais facilmente excretados na urina, principalmente ácido monometilarsônico (MMA) e ácido dimetilarsínico (DMA). O As-i é encontrado no arroz (Oryza sativa L.), principalmente quando o cultivo ocorre pelo método irrigado, que leva a uma maior mobilização de elementos presentes no solo. Neste estudo, foram avaliadas 6 diferentes cultivares brasileiras de arroz quanto à predileção pela captação de As (EPAGRI 109, EPAGRI 108, SCS BRS Tiotaka, SCS 114 Andosan, Maranhão e Cáqui). Para cada cultivar foram plantados grupos controles (não expostos, n=4) e expostos (n=4). No grupo exposto, para cada kg de solo, foram adicionados 10 mg de As5+. Nos grupos controle não adicionou-se As5+, sendo submetidos às mesmas condições de solo, irrigação, temperatura e umidade. Após a completa maturação das plantas foram feitas determinações de As total (As-t) em raízes, solo, colmos e grãos por espectrometria de massas com plasma indutivamente acoplado (ICP-MS) e a especiação química de As nos grãos foi feita por HPLC-ICP-MS. Uma elevada capacidade de captação do As foi observada na seguinte ordem crescente: grãos

Title in English

Uptake and accumulation evaluation of arsenic in different Brazilian rice cultivars

Keywords in English

arsenic
Brazilian cultivars
chemical speciation
ICP-MS
Rice (Oryza sativa L.)

Abstract in English

Arsenic (As) is a nonessential element to man, found in the environment in inorganic (As-i) and organic forms (As-o). Inorganic species, arsenite and arsenate (As3+ and As5+) are the most toxic, and may interfere in biochemical reactions, cellular redox status, formation of adenosine triphosphate (ATP) and generate oxidative damage leading to cell proliferation and cancer. As-i can be methylated in the body and in the environment generating metabolites which are less reactive with components of organisms and more easily excreted in the urine, mainly monomethylarsonous acid (MMA) and dimethylarsinous acid (DMA). As-i is found in rice (Oryza sativa L.), especially when the crop is flooded, which leads to greater mobilization of elements present in the soil. In this study, Brazilian rice varieties were evaluated and the predilection for As uptake in 6 different cultivars (EPAGRI 109, EPAGRI 108, BRS Tiotaka SCS, SCS 114 Andosan, Maranhão and Cáqui). For each cultivar it were planted controls (untreated, n = 4) and exposed (n = 4). In the group exposed, for each kg of soil was added 10 mg of As5+. Control groups were not added As5+, being submitted to the same conditions of soil, irrigation, temperature and humidity. After complete plant maturation were made determinations of the total Arsenic (As-t) in soil, roots, shoots and grains were performed by Inductively Coupled Plasma Mass Spectrometry (ICP-MS) and the chemical speciation of the grains was performed by HPLC-ICP-MS. A high As uptake ability was observed in the following order: grain

 

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Publishing Date

2015-11-04

 

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