scispace - formally typeset
Search or ask a question
Topic

Trace metal

About: Trace metal is a research topic. Over the lifetime, 5125 publications have been published within this topic receiving 181046 citations.


Papers
More filters
Journal ArticleDOI
TL;DR: Electron paramagnetic resonance (EPR) measurements showed that the particulate samples collected during bush fires generate more toxic hydroxyl radicals than those in the background air, due to the presence of more soluble iron ions.
Abstract: Toxicological studies have implicated trace metals adsorbed onto airborne particles as possible contributors to respiratory and/or cardiovascular inflammation. In particular, the water-soluble metal content is considered to be a harmful component of airborne particulate matter. In this work, the trace metal characteristics of airborne particulate matter, PM2.5, collected in Singapore from February to March 2005 were investigated with specific reference to their bioavailability. PM2.5 mass concentrations varied between 20.9 mug/m3 and 46.3 microg/m3 with an average mass of 32.8 microg/m3. During the sampling period, there were several bushfires in Singapore that contributed to sporadic increases in the particulate air pollution, accompanied by an acrid smell and asthma-related allergies. The aerosol samples were subjected to analysis of trace elements for determining their total concentrations as well as their water soluble fractions. Our results showed an increase in concentration of several water-soluble trace metals during bushfires compared to their urban background levels in Singapore. In order to measure the human exposure to particulate air pollution, the daily respiratory uptake (DRU) of several trace metals was calculated and compared between haze and nonhaze periods. The DRU values were significantly higher for several metals, including Zn, Cu, and Fe, during bushfires. Electron paramagnetic resonance (EPR) measurements showed that the particulate samples collected during bush fires generate more toxic hydroxyl radicals (OH.) than those in the background air, due to the presence of more soluble iron ions.

66 citations

Journal ArticleDOI
TL;DR: The multivariate approach proved to be a sensitive means for the detection of trace metal contamination and factors likely to be important in determining the harmful effects of traceMetal contamination in the field include the particular metals under consideration, flow rate and stability of the substrata.
Abstract: The ecological effects of mine effluents on the South Esk River were investigated over 2 years on a 170-km section of the river. Quantitative samples of benthic macroinvertebrates were collected at eight sites (three above the trace metal inflow and five below) using an air-lift sampler. Drifting fauna were also collected in the river adjacent to the point of trace metal inflow and in a tributary entering the contaminated section. As far as 80 km downstream from the source of trace metals; the numbers of individuals and the numbers of taxa were reduced in relation to upstream sites. From the 29 most commonly occurring taxa, three groups have been defined by clustering strategies: (a) taxa that were abundant at both contaminated and uncontaminated sites (a leptocerid caddisfly and a baetid mayfly); (b) taxa that were most abundant at sites upstream of the contaminated section of river (two mollusc species, four species of leptophlebiid mayfly and five species of caddisfly); (c) taxa whose numbers were highest at sites below the source of contamination (six dipteran species, four species of caddisfly, one mollusc species, one amphipod species and one species of water mite). Factors likely to be important in determining the harmful effects of trace metal contamination in the field include the particular metals under consideration, flow rate and stability of the substrata. There is little agreement between the acute lethal concentrations of metals determined by other workers in laboratory studies and the concentrations found to produce harmful effects in the South Esk River. The multivariate approach proved to be a sensitive means for the detection of trace metal contamination. Thecomposition of the drifting fauna was also altered by the trace metal contamination. Thenumbers of rhyacophilidcaddisflies were higher in the contaminated section of river and those of the baetid mayflies and helminthid beetles were lower.

66 citations

Journal ArticleDOI
TL;DR: In this article, a model of the equilibrium speciation, kinetic reaction, and transport of trace metals in the presence of biodegradation of organic substrates in saturated porous media is formulated.
Abstract: A model has been formulated of the equilibrium speciation, kinetic reaction, and transport of trace metals in the presence of biodegradation of organic substrates in saturated porous media. Kinetics of various processes (biodegradation, chemical reactions, and precipitation and dissolution of minerals) together with transport processes (advection, bioturbation, and diffusive/dispersive mixing) are quantified in a set of coupled mass balance equations (for the organic substrate, electron acceptors, reduced species, and trace metals). These steady state, one-dimensional equations are discretized using a second-order-accurate finite difference approximation. A pE is estimated at each node in the domain on the basis the concentrations calculated and the half reaction for the dominant terminal electron acceptor at that location. The dynamic model is coupled iteratively to a modified version of the U.S. Environmental Protection Agency's MINTEQA2, which calculates equilibrium chemical speciation (including aqueous speciation, adsorption, and precipitation of minerals) at each node of the domain. The primary dependent variables are the total dissolved concentrations of the aqueous species together with the solid concentrations of the minerals. To demonstrate that this formulation can simulate biodegradation using reaction rates consistent with published values, simulations are compared to data from the sediment pore waters of a small lake. Simulations are presented of the transport and reaction of arsenic in lake sediments to illustrate how this model can be used to evaluate trends in trace metal mobility as affected by various water quality parameters through their influence on the biogeochemistry of natural systems.

66 citations

Journal ArticleDOI
TL;DR: The very impressive decrease in heavy metal concentrations within the Marseille area represents an indisputable evidence of the improvement of the seawater quality resulting from 12 years' operation of the Marseilles sewage plant and might reflect an overall improvement in the seaw water quality of the NW Mediterranean.

66 citations

Journal ArticleDOI
TL;DR: The distribution of the trace metals iron (Fe), copper (Cu) and cadmium (Cd) along with hydrological parameters (salinity, temperature and reactive phosphate) across the New Zealand continental shelf near Otago Peninsula have been studied in this article.

66 citations


Network Information
Related Topics (5)
Organic matter
45.5K papers, 1.6M citations
88% related
Sediment
48.7K papers, 1.2M citations
85% related
Water quality
67.1K papers, 945.1K citations
83% related
Sorption
45.8K papers, 1.3M citations
81% related
Groundwater
59.3K papers, 1M citations
80% related
Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202394
2022225
2021197
2020220
2019193
2018186