RESUMO
ABSTRACT A hydroponic experiment was carried out to investigate the effect of phosphorus (P) nutrition on arsenic (As) uptake and translocation within the seedlings of rice cultivars. The experiment occurred in three stages: I 5 days of acclimatization (nutritive solution); II 10 days under P (0.0 and 0.09 mM) and As (0.0 and 100 mM) treatments; III 5 days under recovery. The As exposure had significant effect reducing dry weights of shoots or roots, resulted in elevated concentrations of As in shoot tissues. BR-IRGA 409 showed the highest susceptibility to As in biomass production and root system parameters regardless the P level. This cultivar showed contrasting responses of As translocation to shoot tissue dependent on P levels, with the highest As concentration under low P and lowest under normal P levels. P nutrition was most striking on plants recovery for all cultivars under As exposure. Clearer separation of cultivars for phosphorus use efficiency (PUE) occurred at lower shoot P contents, that was, at higher levels of P deficiency stress. IRGA 424 showed higher PUE as compared to the others cultivars. Our results go some way to understanding the role of P nutrition in controlling the effects of As in rice shoots.
Assuntos
Fósforo/farmacologia , Arsênio/farmacocinética , Oryza/efeitos dos fármacos , Oryza/metabolismo , Fósforo/análise , Arsênio/análise , Valores de Referência , Sementes/efeitos dos fármacos , Sementes/metabolismo , Fatores de Tempo , Transporte Biológico , Reprodutibilidade dos Testes , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/metabolismo , Hidroponia/métodos , Biomassa , FertilizantesRESUMO
Arsenic is a major environmental pollutant and exposure occurs through environmental, occupational and medicinal sources. The contaminated drinking water is the main source of exposure and affected countries are India (West Bengal), Bangladesh, China, Taiwan, Thailand, Chile, Argentina and Romania. Concentrations of arsenic in affected areas are several times higher than the maximum contamination level (MCL) (10 microg/l). Arsenic exposure to human results in degenerative, inflammatory and neoplastic changes of skin, respiratory system, blood, lymphatic system, nervous system and reproductive system. There is no particular remedial action for chronic arsenic poisoning. Low socioeconomic status and malnutrition may increase the risk of chronic toxicity. Early intervention and prevention can give the relief to the affected population.
Assuntos
Animais , Arsênio/farmacocinética , Intoxicação por Arsênico/tratamento farmacológico , Quelantes/uso terapêutico , Terapia por Quelação , Exposição Ambiental/efeitos adversos , Poluentes Ambientais/farmacocinética , Humanos , Pneumopatias/induzido quimicamente , Doenças do Sistema Nervoso Periférico/induzido quimicamente , Dermatopatias/induzido quimicamenteRESUMO
Humans can be exposed to arsenic from a variety of environmental, occupational and medicinal sources. Exposure from drinking water is the most common source nowadays. Inorganic arsenic is metabolized by two main biochemical reactions: reduction and oxidative methylation. Recent studies have confirmed a reactivation of the toxic effects of arsenic associated with such methylation process, because the methylated metabolites, especially the trivalent forms, are more toxic than the inorganic arsenicals. Chronic exposure to arsenic can cause a variety of cancerous and noncancerous health hazards in humans. The main non-cancerous health hazards include cardiovascular disease, skin lesions, neurological problems, diabetes mellitus and hypertension.
Assuntos
Animais , Arsênio/farmacocinética , Doenças Cardiovasculares/induzido quimicamente , Exposição Ambiental/efeitos adversos , Poluentes Ambientais/farmacocinética , Humanos , Inteligência/efeitos dos fármacos , Doenças do Sistema Nervoso Periférico/induzido quimicamente , Dermatopatias/induzido quimicamenteRESUMO
Se ha cuantificado arsénico por el método espectrofotométrico de Vasac y Sedivec en tubérculos de papas de cultivos expuestos. Las muestras proceden del Valle del Mantaro (Junín) y de las zonas de Cañete, Barranca, Puente Piedra y Huachipa (Lima). La investigación se realizó en 50 tubérculos de diferentes variedades y formas de riego. El nivel medio de Arsénico en las muetras fue de 0,2572 ppm ñ 0,0132, con una desviación standard de 0,0927ñ0,0093 y cifras extremas de 0,095-0.500 ppm. Los valores promedios obtenidos de arsenico en los tubérculos es menos que los valores máximos aceptables de Canadá ya que solo constituyen el 25,72 por ciento de 1ppn, que es la cantidad máxima de arsénico aceptada en la papa, ya que a partir de ella produce efectos nocivos y tóxicos.
Assuntos
Produção Agrícola , Produção Agrícola/normas , Arsênio/isolamento & purificação , Arsênio/análise , Arsênio/efeitos adversos , Arsênio/farmacocinética , Arsênio/farmacologia , Arsênio/toxicidade , Solanum tuberosum/química , Solanum tuberosum/efeitos dos fármacos , Solanum tuberosum/toxicidadeRESUMO
Se determinó que del total de muestras analizadas el 84.90 por ciento se encuentran sobre el límite permisible por la OMS (0.05 mg/lt). Se determinó, que no existe diferencia sustancial en concentraciones de arsénico como contaminante, en aguas de consumo humano que superan el nivel permitido entre: Agua potable (81,48 por ciento), agua rio, agua manantial, agua pozo (88,46 por ciento).