RESUMO
Arsenic is the most important contaminant of the environment in northern Chile. Soil samples and plant organs from three native plant species, Pluchea absinthioides, Atriplex atacamensis and Lupinus microcarpus, were collected from arid zones in order to determine the total and bioavailable arsenic concentrations in soils and to assess the bioconcentration factor (BCF) and transport index (Ti) of arsenic in the plants. Total arsenic concentrations in soils (pH 8.3-8.5) where A. atacamensis and P. absinthioides were collected, reached levels considered to be contaminated (54.3 ± 15.4 and 52.9 ± 9.9 mg kg⻹, respectively), and these values were approximately ten times higher than in soils (pH 7.6) where L. microcarpus was collected. Bioavailable arsenic ranged from 0.18 to 0.42% of total arsenic concentration. In the three plant species, arsenic concentration in leaves were significantly (p ≤ 0.05) higher than in roots. L. microcarpus showed the highest arsenic concentration in its leaves (9.7 ± 1.6 mg kg⻹) and higher values of BCF (1.8) and Ti (6.1), indicating that this species has a greater capacity to accumulate and translocate the metalloid to the leaf than do the other species.
Assuntos
Arsênio/análise , Gleiquênias/metabolismo , Poluentes do Solo/análise , Solo/química , Arsênio/metabolismo , Chile , Monitoramento Ambiental , Concentração de Íons de Hidrogênio , Folhas de Planta/metabolismo , Raízes de Plantas/metabolismo , Caules de Planta/metabolismo , Poluentes do Solo/metabolismoRESUMO
Rh(I) complexes adsorbed on polymers, as a way to improve their transport and solubility properties, were studied as antitumor agents. The binding constants of the complexes to the polymer were evaluated in order to determine the conditions for maximum association to the vehicle. The toxicity of the pure complexes and those bound were determined in vivo using female mice. [Rh(NBD)(2,4N)]CIO4, complex A; where NBD = norbornadiene, (2,4N) = 3,3'-dimethylene-2,2'-di-1,8-naphthyridine, was investigated on primary solid tumors and ascitic tumors. [Rh(NBD)(3,4N)]CIO4, complex B; where (3,4N) = 3,3'-trimethylene-2,2'-di-1,8-naphthyridine, was investigated on ascitic tumors. These Rh(I) complexes appear to be promising drugs because of their solubility in aqueous polymer, which make them easier to handle in comparison with the neutral species. These complexes show a similarity to cisplatin by reducing tumor growth and by increasing the survival life span of mice. Poly (oxyethylene) was used to solubilize these poorly water-soluble compounds and to stabilize the compounds in the solution before injection. These studies suggest that both complexes, A and B, are good candidates for tumor control growth and increase the survival time.