Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 2 de 2
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Environ Monit Assess ; 143(1-3): 345-54, 2008 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-17987397

RESUMO

Water from 15 sampling stations in Tasik Chini (Chini Lake), Peninsular Malaysia were sampled for 12 months from September 2004 until August 2005 and analyzed for 11 metals including iron (Fe), aluminum (Al), manganese (Mn), barium (Ba), zinc (Zn), lead (Pb), copper (Cu), cadmium (Cd), nickel (Ni), chromium (Cr) and cobalt (Co). Results showed that the mean (min-max) metal concentrations (in micrograms per liter) in Tasik Chini waters for the 12 months sampling based on 15 sampling stations (in descending order) for Fe, Al, Mn, Ba, Zn, Pb, Cu and Cd were 794.84 (309.33-1609.07), 194.53 (62.37-665.93), 29.16 (16.68-79.85), 22.07 (15.64-29.71), 5.12 (2.224-6.553), 2.36 (1.165-4.240), 0.832 (0.362-1.443) and 0.421 (0.254-0.696) respectively. Concentration for three metals i.e. Ni, Cr and Co were too low and not detected by the graphite furnace Atomic Absorption Spectrophotometry (AAS). Comparison with various water quality standards showed that the mean metals concentration in surface water of Tasik Chini were low and within the range of natural background except for Fe and Al. In general, metal concentrations in Tasik Chini water varied temporally and spatially. The main factors influencing these metal concentrations in the water were the raining season and mining activities. Stations located at Tanjung Jerangking and Melai areas were the most effected due to those factors.


Assuntos
Água Doce/análise , Metais Pesados/análise , Estações do Ano , Poluição da Água/análise , Alumínio/análise , Cádmio/análise , Cromo/análise , Cobalto/análise , Cobre/análise , Monitoramento Ambiental/métodos , Ferro/análise , Chumbo/análise , Malásia , Manganês/análise , Níquel/análise , Poluição da Água/prevenção & controle , Zinco/análise
2.
Cell Mol Biol (Noisy-le-grand) ; 45(4): 413-22, 1999 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-10432188

RESUMO

Received January 4, 1999; Accepted March 25, 1999 Secondary ion mass spectrometry (SIMS), electron probe X-ray microanalysis (EPMA) and transmission electron microscopy (TEM) were used to study the tissular distribution and subcellular localization of aluminium (Al) precipitate in roots of Viciafaba. The broad bean plant, grown in nitrate solution with 193 microM Al3+ at pH 4.8, for 15 days showed Al deposits in the roots. Al accumulation was not detected in the stems nor in the leaves. Al was found mainly localized on the root's surfaces and within the cell walls of the cortical cells. Al signal was not detected in the vascular tissues. Two weeks exposure to Al caused ultrastructural changes in cortical cells and sometimes a complete disruption of these cells. Deposition of Al in form of insoluble complexes associated with phosphorus, appeared as electron opaque materials in the vacuoles of disrupted cortex cells and in the intercellular inclusions. The leaves turned yellowish at the end of 15 days exposure. The use of electron microprobe, to investigate the same tissues as the ones investigated by SIMS, provided complementary results on aluminium allocation.


Assuntos
Alumínio/análise , Fabaceae/metabolismo , Plantas Medicinais , Microanálise por Sonda Eletrônica , Microscopia Eletrônica , Raízes de Plantas/citologia , Raízes de Plantas/metabolismo , Espectrometria de Massa de Íon Secundário , Frações Subcelulares
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...