نتایج جستجو برای: trace metals

تعداد نتایج: 126654  

2016
Aimée Mudekereza Musimwa Gray Wakamb Kanteng Hermann Tamubango Kitoko Oscar Numbi Luboya

INTRODUCTION The role of trace metals elements in human nutrition can no longer be ignored. Deficiency caused by inadequate dietary intake, secondary deficiencies often under - estimated, and iatrogenic deficiencies lead to pathologies such as infections and others. For this reason their dosages are particularly important to assess disease severity and to facilitate early treatment or improve p...

Journal: :Water science and technology : a journal of the International Association on Water Pollution Research 2013
Li Jing Li Fadong Liu Qiang Song Shuai Zhao Guangshuai

For this study, 34 water samples were collected along the Wei River and its tributaries. Multivariate statistical analyses were employed to interpret the environmental data and to identify the natural and anthropogenic trace metal inputs to the surface waters of the river. Our results revealed that Zn, Se, B, Ba, Fe, Mn, Mo, Ni and V were all detected in the Wei River. Compared to drinking wate...

2009
Jorge Herrera Susana Rodriguez Armando P. Baez

Measurements of trace metals and inorganic ions were carried out on PM10 aerosols sampled at two sites in the city of San Jose, Costa Rica. Samples were collected with a Thermo Andersen high volume PM10 sampler on glass fiber and quartz filters. The ions SO4 2, NO3 , Cl , F , PO4 3, NH4 + , K + , Na + , Ca 2+ and Mg 2+ were analyzed by ion chromatography and the trace metals V, Cu, Cr, Pb, Ni, ...

2003
S. Sadasivan R. M. Tripathi

Trace metals are intrinsic, natural constituents of our environment. Apart from the natural sources, several anthropogenic ones also contribute to metal concentrations in the environment. Some of the anthropogenic sources of the metals in the environment are: mining, smelting, production and use of the compounds and materials containing the metals, burning of fossil fuels, waste dumping and lea...

Journal: :The Proceedings of the Nutrition Society 1995
I Bremner J H Beattie

It has long been evident that the metabolism of trace elements cannot be considered in isolation. A wide range of nutritional and physiological factors can influence their uptake, transport and storage, with subsequent enhancement of susceptibility to deficiency or toxicity states. Interactions occur with other trace elements and these can be classified as competitive or non-competitive, direct...

2004
K. W. Bruland

Since the early 1970s, marine chemists have gained a first-order understanding of the concentrations, distributions, and chemical behaviors of trace metals in seawater. Important factors initiating this quantum leap in knowledge were major advances in modern analytical chemistry and instrumentation, along with the development and adoption of clean techniques. An instrumental development in the ...

Journal: :Plant physiology 1950
W W Heck L F Bailey

Plant nutrition studies frequently require nearly complete elimination of trace metals from the nutrient media in which the plants are to be grown. Conventional methods of purification by recrystallization and precipitation have been used for this purpose in some studies. These have proved more difficult and less effective than the adsorption technique developed by STEINBERG (11) and improved b...

پورمقدس, حسین, پیشکار, احمدرضا, کاوه زاده, فخرالملوک,

Introduction: Recent investigations have detected the presence of significant levels of heavy metals (chromium, lead and cadmium) in toys and other PVC products manufactured for children. In some countries, addition of compounds containing toxic metals to toys are limited or prohibited. Methods: To evaluate the safety of some of the plastic toys in the city of Isfahan with respect to toxic tr...

2007
G. S. Toor B. E. Haggard A. M. Donoghue

Poultry litter contains many trace elements such as As, Cu, and Zn, and its land application may lead to the accumulation of these elements in soils, especially near the soil surface. The objectives of this study were to determine the total amount of trace elements and evaluate the effect of litter granulation and various litter to water extraction ratios on water extractable trace elements in ...

1999
Roberta A. Carvalho Mark C. Benfield Peter H. Santschi

A large fraction of the trace metal pool in estuarine and coastal waters is complexed with colloidal-sized macromolecular organic matter. Bioaccumulation and bioavailability studies of trace metals have generally utilized freeionic dissolved metal ions. Consequently, little is known about the uptake and depuration kinetics of the colloidally bound species. Chemical characteristics such as the r...

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