نتایج جستجو برای: trace metals

تعداد نتایج: 126654  

Journal: :Environmental pollution 2007
Neal W Menzies Michael J Donn Peter M Kopittke

Despite its environmental (and financial) importance, there is no agreement in the literature as to which extractant most accurately estimates the phytoavailability of trace metals in soils. A large data set was taken from the literature, and the effectiveness of various extractants to predict the phytoavailability of Cd, Zn, Ni, Cu, and Pb examined across a range of soil types and contaminatio...

2015
Patrycja Siudek Marcin Frankowski Jerzy Siepak

This work presents the first results from winter field campaigns focusing on trace metals and metalloid chemistry in the snow cover from an urbanized region in central Poland. Samples were collected between January and March 2013 and trace element concentrations were determined using GF-AAS. A large inter-seasonal variability depending on anthropogenic emission, depositional processes, and mete...

Journal: :Marine pollution bulletin 2014
B Lourino-Cabana G Billon L Lesven K Sabbe D-C Gillan Y Gao M Leermakers W Baeyens

Seasonal variation in trace metal contamination in surface sediments was studied through high resolution profiles assessed monthly by DGT probes in muddy sediments of the North Sea. General parameters such as pH, temperature, dissolved oxygen and sulfides were also recorded to estimate their role in the speciation of trace metals. Experimental data were included in a thermodynamic equilibrium m...

2006
R. Dobrowolski M. Skowrońska

The content of selected trace metals (Cd, Cr, Hg, Pb, Zn) and their distribution in superficial water, bottom sediments and in muscular tissue of fishes (roach, perch, bream) and mollusks (taken from the Zemborzyce Reservoir) were examined using atomic absorption spectrometry (AAS). A comparison of the trace elements content in investigated constituents of the Zemborzyce Reservoir was carried o...

Journal: :Applied biochemistry and biotechnology 2004
Douglas C Elliott Keith L Peterson Danielle S Muzatko Eric V Alderson Todd R Hart Gary G Neuenschwander

Model compound testing was conducted in a batch reactor to evaluate the effects of trace contaminant components on catalytic hydrogenation of sugars. Trace components are potential catalyst poisons when processing biomass feedstocks to value-added chemical products. Trace components include inorganic elements such as alkali metals and alkaline earths, phosphorus, sulfur, aluminum, silicon, chlo...

2013
Nsikak U. Benson Winifred U. Anake Ifedolapo O. Olanrewaju

This article presents a review of the analytical relevance of trace metal speciation analysis, which must be considered in environmental and biophysicochemical systems for reliable and efficient assessment and monitoring of trace metals. Examples are given of methodological approaches used for speciation analysis. An overview of speciation analysis in sediments, aquatic ecosystems and agrosyste...

Journal: :Applied and environmental microbiology 1982
R C Strachan H Aranha J S Lodge J E Arceneaux B R Byers

A teflon chemostat constructed for studies of microbial trace metal metabolism is described. The utility of this continuous culture system was demonstrated with Streptococcus mutans, in which iron and manganese stimulated growth in ranges of 0.18 to 0.45 and 18 to 54 microM, respectively. This device should facilitate studies of the effect of trace metals on a variety of physiological functions.

2014
V Nisha

Present study consists geochemical variations and spatial distribution of trace elements (Fe, Mn, Cr, Co, Cu, Ni, Pb and Zn) of the ocean floor sediments collected along the continental shelf off East coast Tamil Nadu (Chennai to Velanganni) during the 2009 southwest monsoon period. Results indicate sand dominance with abundant calcareous debris and shell fragments. Normalisation of trace metal...

Journal: :Journal of trace elements in medicine and biology : organ of the Society for Minerals and Trace Elements 2005
Zhenli L He Xiaoe E Yang Peter J Stoffella

Trace elements mean elements present at low concentrations (mg kg-1 or less) in agroecosystems. Some trace elements, including copper (Cu), zinc (Zn), manganese (Mn), iron (Fe), molybdenum (Mo), and boron (B) are essential to plant growth and are called micronutrients. Except for B, these elements are also heavy metals, and are toxic to plants at high concentrations. Some trace elements, such a...

2013
Stephen Juma Mulware

Cancer is known to be a multi-step process, which involves different stages including initiation, promotion, progression and metastasis. Chemical carcinogens including most trace elements can change any of these processes to induce their carcinogenic effects. Various studies confirm that cancer arises from the accumulation of irreversible DNA damage, which results from multiple mutations in cri...

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