نتایج جستجو برای: metals

تعداد نتایج: 63791  

2007
Robert O. Wright Andrea Baccarelli

Metals are ubiquitous and play a critical role in neurobiology. Transition metals are important because they alter the redox state of the physical environment. Biologically, transition metals catalyze redox reactions that are critical to cellular respiration, chemical detoxification, metabolism, and even neurotransmitter synthesis. Many metals are both nutrients and neurotoxicants, such as iron...

Journal: :Environmental Health Perspectives 1998
M A Peraza F Ayala-Fierro D S Barber E Casarez L T Rael

There is growing evidence that micronutrient intake has a significant effect on the toxicity and carcinogenesis caused by various chemicals. This paper examines the effect of micronutrient status on the toxicity of four nonessential metals: cadmium, lead, mercury, and arsenic. Unfortunately, few studies have directly examined the effect of dietary deficiency or supplementation on metal toxicity...

Journal: :Journal of environmental monitoring : JEM 2009
Jaehyun Lim Cheolsoo Lim Liya E Yu

This study characterizes the size distribution and composition of metals in diesel exhaust particulates (DEPs) emitting from four driving conditions. We quantified 17 metals in DEPs (34-1000 nm) with a total concentration ranging from 5.4-7.0 microg/m(3). Depending on driving conditions, ultrafine (<100 nm) and accumulation-mode DEPs carried up to 41% and 75% of the quantified metals, respectiv...

2014
Pandey Govind

The heavy metals chiefly include Pb, Hg, Cd, Cr, Cu, Zn, Mn, Ni, Ag, etc. The heavy metals, viz., As, Cd, Pb and Hg are considered most toxic to humans, animals, fishes and environment. Excessive concentrations of heavy metals are detrimental. They destabilize ecosystems because of their bioaccumulation in organisms, and toxic effects on biota and even death in most living beings. All heavy met...

Journal: :Environment international 2004
Judith S Weis Peddrick Weis

Marshes have been proposed as sites for phytoremediation of metals. The fate of metals within plant tissues is a critical issue for effectiveness of this process. In this paper we review studies that investigate the effects of plants on metals in wetlands. While most of these marsh plant species are similar in metal uptake patterns and in concentrating metals primarily in roots, some species re...

2002

Metals are essential cofactors for bio-chemical processes, including oxidative phosphorylation, gene regulation and free-radical homeostasis. Abnormalities in metal ions concentration in organisms, lead towards the eco-physiological hazards in the aquatics. In aquatic organisms, metal absorption involves transfer of metals to the circulatory system following: uptake by the apical membrane; move...

Journal: :Environmental Health Perspectives 1995
T Clarkson

Metals have been mined and used since ancient times. The industrial era has seen a sharp increase in both the amounts and variety of metals that find applications in industry. The inadvertent release of metals, such as from fossil fuel consumption, also adds to the global burden. A number of catastrophic outbreaks have alerted us to the occupational and environmental health risks. Life on this ...

2013
Linxian Liao Junzeng Xu Shizhang Peng Zhenfang Qiao Xiaoli Gao

To reveal the impact of Non-Flooding controlled Irrigation (NFI) on the bioavailability and bioaccumulation of metals (Cu, Pb, Cd and Cr) in rice fields, metals concentration in different organs of rice plant growing under both Flooding Irrigation (FI) and NFI were measured. It indicated that metals concentrations in root are always the highest one among all the plant organs and in the spike is...

1997
J. P. Dekker A. Lodder

A multiple scattering formulation for the electromigration wind force on atoms in dilute alloys is developed. The theory describes electromigration via a vacancy mechanism. The method is used to calculate the wind valence for electromigration in various host metals having a close-packed lattice structure, namely aluminum, the noble metals copper, silver, and gold, and the 4d transition metals. ...

Journal: :Waste management 2017
Magnus Andersson Maria Ljunggren Söderman Björn A Sandén

Improved recycling of end-of-life vehicles (ELVs) may serve as an important strategy to address resource security risks related to increased global demand for scarce metals. However, in-depth knowledge of the magnitude and fate of such metals entering ELV recycling is lacking. This paper quantifies input of 25 scarce metals to Swedish ELV recycling, and estimates the extent to which they are re...

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