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Metal Contamination (metal + contamination)

Distribution by Scientific Domains

Life Sciences	59%
Earth and Environmental Science	18%
Engineering	9%
3 Other Domains	14%

Kinds of Metal Contamination

heavy metal contamination

Selected Abstracts

Metal contamination in aquatic environments: Science and lateral management by Samuel N. Luoma and Phillip S. Rainbow

INTEGRATED ENVIRONMENTAL ASSESSMENT AND MANAGEMENT, Issue 3 2009
Glenn Suter SETAC Reviews Editor
No abstract is available for this article. [source]

Contamination by nickel, copper and zinc during the handling of euro coins

CONTACT DERMATITIS, Issue 4 2003
Paul-Guy Fournier
The introduction of the euro has revived interest in the risk of nickel allergy due to the handling of coins. In the present work, the transfer of metallic contamination during the manipulation of coins is examined by means of leaching experiments and manipulation tests. It is shown that pre-existing metallic species present on the surface of the coins are the major source of contamination during manipulation, and that friction inherent to everyday usage contributes predominantly to their transfer to the hands. The comparison of coins as to their relative risks of metal contamination should therefore rely on tests that simulate the friction inherent in everyday human handling. Carrying out such tests with the newly issued 1, and 2, pieces, we find, contrary to long-term leaching measurements, that the euros release less nickel than previously circulated pure-nickel coins, but that this decrease is less pronounced than might have been hoped for on the basis of their surface composition. When the coins are rubbed to a shiny polish before manipulation, contamination of the fingers is reduced by more than a factor of 10. A comparison of coins used in France indicates that the introduction of the common currency has led to a fourfold reduction in contamination by nickel, while causing a 45% increase in contamination by copper. [source]

Direct Simultaneous Determination of Cu, Ni and V in Seawater Using Adsorptive Cathodic Stripping Voltammetry with Mixed Ligands

ELECTROANALYSIS, Issue 10 2005
A. Cobelo-García
Abstract An analytical procedure is proposed for the direct simultaneous determination in a single scan of Cu, Ni and V in seawater by means of adsorptive cathodic stripping voltammetry (ACSV) with mixed ligands (DMG and catechol). Optimum conditions for the determination of these three elements were studied. Detection limits of the technique depended upon the reproducibility of the procedura blank, and were found to be 0.5,nM for Cu, 0.4,nM for Ni and 0.3,nM for V. The method is suitable for the analysis of estuarine, coastal and open-ocean waters, and especially to study the metal contamination in areas subject to oil spill events. [source]

Metal concentrations, sperm motility, and RNA/DNA ratio in two echinoderm species from a highly contaminated fjord (the Sørfjord, Norway),

ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 7 2008
Ana I. Catarino
Abstract The present study evaluated the effects of field metal contamination on sperm motility and the RNA/DNA ratio in echinoderms. Populations of Asterias rubens and Echinus acutus that occur naturally along a contamination gradient of sediments by cadmium, copper, lead, and zinc in a Norwegian fjord (the Sørfjord) were studied. Sperm motility, a measure of sperm quality, was quantified using a computer-assisted sperm analysis system. The RNA/DNA ratio, a measure of protein synthesis, was assessed by a one-dye (ethidium bromide)/one-enzyme (RNase), 96-well microplate fluorometric assay. Although both species accumulate metals at high concentrations, neither sperm motility parameters in A. rubens nor the RNA/DNA ratio in both species were affected. The Sørfjord is still one of the most metal-contaminated marine sites in Europe, but even so, populations of A. rubens and E. acutus are able to endure under these conditions. [source]

In situ and laboratory bioassays with Chironomus riparius larvae to assess toxicity of metal contamination in rivers: The relative toxic effect of sediment versus water contamination

ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 9 2007
Mafalda S. Faria
Abstract We used bioassays employing head capsule width and body length increase of Chironomus riparius larvae as end points to evaluate metal contamination in streams. Bioassays were performed in situ near an abandoned Portuguese goldmine in the spring of 2003 and 2004. Bioassays also were performed under laboratory conditions with water and sediment collected from each stream to verify if laboratory bioassays could detect in situ toxicity and to evaluate the relative contribution of sediment and water to overall toxicity. We used field sediments with control water and control sediments with field water to discriminate between metal contamination in water and sediment. Field water with dry and sieved, organic matter,free, and nontreated sediments was used to determine the toxicity of heavy metals that enter the organism through ingested material. In both in situ and laboratory bioassays, body length increase was significantly inhibited by metal contamination, whereas head capsule width was not affected. Body length increase was more affected by contaminated sediment compared to contaminated water. The lowest-effect level of heavy metals was observed in the dry and sieved sediment that prevented ingestion of sediment particles by larvae. These results suggest that body length increase of C. riparius larvae can be used to indicate the impact of metal contamination in rivers. Chironomus riparius larvae are more affected by heavy metals that enter the organism through ingested sediment than by heavy metals dissolved in the water column. Nevertheless, several factors, such as the particle size and organic matter of sediment, must be taken into account. [source]

Differential tolerance among cryptic species: A potential cause of pollutant-related reductions in genetic diversity

ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 9 2004
Axayácatl Rocha-Olivares
Abstract Differential mortality of cryptic species (i.e., morphologically similar but genetically distinct sibling species) may contribute to observed reductions in genetic diversity at contaminated sites if the members of a complex of cryptic species exhibit differential responses to the contaminants that are present. We conducted toxicity bioassays with both polynuclear aromatic hydrocarbon and metal contamination on Cletocamptus fourchensis and C. stimpsoni from two intensively sampled locations. Previous molecular and detailed morphological analyses segregated these as cryptic species from the cosmopolitan C. deitersi. We found that these species occur together at two field sites and that they exhibit unique toxic responses to heavy metals, suggesting differential tolerances at contaminated sites. These findings suggest that reported losses of genetic diversity at contaminated sites may represent a reduction in species diversity rather than a loss of the presumed less-tolerant genotypes within a species. They also suggest that members of a cryptic species complex should not be used in laboratory toxicity tests unless populations are genetically characterized. Future studies using genetic diversity as a marker of contaminant effects should consider the possibility of undetected cryptic species. [source]

The influence of pH and salinity on the toxicity of heavy metals in sediment to the estuarine clam Ruditapes philippinarum,

ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 5 2004
Inmaculada Riba
Abstract An approach is presented for determining the influence of two key variables, pH and salinity(S), on the toxicity of four common heavy metals bound to sediments in estuaries. Two samples of environmental sediment taken from two estuaries in southern Spain (the Huelva estuary and the Guadalquivir River estuary), together with a dilution of toxic mud from the Aznalcóllar (Spain) mining spill (April 1998) were used to determine their toxicity at different values of pH (6.5, 7.5, and 8.5) and salinity (10, 20, and 30) on the estuarine clam Ruditapes philippinarum. Two different endpoints, sublethal, indicated by clam reburial (median effective burial time [ET50]), and relative mortality (median lethal concentration [LC50]), were used to quantify the toxicity associated with the heavy metals. Neither salinity nor pH was found to influence the toxic responses measured by the behavioral endpoint (ET50). However, a strong effect on the LC50 related to pH and salinity was detected, with the toxicity of the heavy metals being increased at low values of both variables (pH = 6.5 and S = 10). The mechanism of heavy metals uptake through water may explain this influence of pH and salinity on the lethal toxicity detected. The results show differences in the toxicity of these heavy metals bound to sediments depending on whether the origin of metal contamination is chronic or acute. [source]

Developing transgenic arabidopsis plants to be metal-specific bioindicators

ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 1 2003
Beth A. Krizek
Abstract Deoxyribonucleic acid (DNA) microarrays provide a means to assess genome-wide expression patterns after exposure of an organism to different xenobiotics. Potential uses for this technology include identification of unknown toxicants, assessment of toxicity of new compounds, and characterization of the cellular mechanisms of toxicant action. Here we describe another use of DNA microarrays in toxicant-specific gene discovery. Combining results from two DNA microarray experiments, we have identified genes from the model plant Arabidopsis thaliana that are induced in response to one but not other heavy metals. The promoters of these genes should be useful in developing metal-specific transgenic biomonitors. To test this idea, we have fused the promoter of one of the newly identified Ni-inducible genes (AHB1) to the ,-glucuronidase (GUS) reporter gene. Arabidopsis plants containing the AHB1::GUS transgene show reporter gene activity when they are grown on media containing Ni but not when grown on media containing Cd, Cu, Zn, or without added metals. Thus, this approach has resulted in the creation of a transgenic strain of Arabidopsis that can report on the presence and concentration of Ni in plant growth media. Such transgenic models can serve as cheap and efficient biomonitors of bioavailable heavy metal contamination in soils and sediments. [source]

Transgenic strains of the nematode Caenorhabditis elegans as biomonitors of metal contamination

ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 8 2000
L. K. Cioci
Abstract Transition metal contamination poses a serious environmental and human health threat. The bioavailability of transition metals in environmental samples can best be assessed with living organisms. A transgenic strain of the free-living soil nematode Caenorhabditis elegans has been engineered for monitoring the bioavailability of metals. A reporter transgene consisting of a fragment of the promoter from the C. elegans metallothionein-2 gene (mtl-2) that controls the transcription of a ,-galactosidase reporter (lacZ) has been integrated into the genome of this organism. By using these transgenic C. elegans, the toxicological response to metals in samples can be quickly measured with a simple histochemical staining assay. The C. elegans that contain the mtl-2:lacZ transgene provide a more sensitive assay of exposure to cadmium, mercury, zinc, and nickel than 24-h LC50 assays or those using nematodes with heat-shock protein,based reporter transgenes. This study demonstrates that C. elegans that contain mtl-2:lacZ transgenes can function as sensitive toxicological indicators of metals. [source]

Decline in the quality of suspended fine particulate matter as a food resource for chironomids downstream of an urban area

FRESHWATER BIOLOGY, Issue 5 2004
Emma J. Rosi-MarshallArticle first published online: 16 APR 200
Summary 1. Urbanization and its associated contamination could degrade the quality of suspended fine particulate organic matter (SFPM) (20 ,m to 1 mm) as a food resource for aquatic insects. SFPM was collected at four sites along the main stem of the Chattahoochee River, which drains metropolitan Atlanta at base and high flow during four seasons. 2. Composition of SFPM was estimated using measures conventionally associated with food quality: bacteria, N/C ratio, caloric content, % inorganic, and % lipids, and metal (Cd, Cu, Pb, and Zn) concentration. In SFPM collected during base flow, % inorganic matter, calories, Cu, Pb, and Zn concentrations increased with cumulative permitted wastewater treatment discharge (an indicator of extent of urbanization upstream). In SFPM samples collected during high flow, % diatoms, Cu, Pb and Zn concentrations increased with urbanization. 3. A growth assay was used as an integrated and direct measure of SFPM quality as a food resource. The instantaneous growth rate (IGR) of chironomids fed SFPM collected during base flow declined downstream of the city. IGRs of chironomids fed SFPM collected at all sites during high flow were as low as the lowest IGR measured during base flow. 4. Insects fed SFPM collected from the Chattahoochee River had IGRs only 20% of those of chironomids fed SFPM collected from the Little Tennessee River, a relatively undisturbed river in North Carolina. The mortality rate of chironomids fed SFPM was not different among sites or rivers. While the decline in SFPM quality in the Chattahoochee River is probably attributable to some aspect of urbanization, the decline was not related to conventional measures of food quality or metal contamination. [source]

Magnetic investigation of heavy metals contamination in urban topsoils around the East Lake, Wuhan, China

GEOPHYSICAL JOURNAL INTERNATIONAL, Issue 2 2007
Tao Yang
SUMMARY Magnetic measurements and heavy metal analyses were performed on 133 samples from the urban soils around the East Lake in Wuhan, China. Samples were collected from four areas with different environmental settings: a heavy industrial area well known for thermal power generation and steel works; villages located in the downwind area of the industrial area; a main road with heavy traffic and roads around the East Lake. Results show that concentrations of magnetic particle and heavy metals in urban topsoils are significantly elevated due to the input of coarser-grained magnetite from industrial (e.g. power generation and steel production) and other anthropogenic activities (e.g. vehicle emissions). Concentration-related magnetic parameters, for example, magnetic susceptibility, saturation isothermal remanent magnetization and anhysteretic remanent magnetization, significantly correlate with the concentration of heavy metals. Moreover, in terms of grain sizes, the magnetic particles of different origins can be efficiently discriminated at the studied region. Therefore, magnetic measurements provide a basis for discrimination and identification of different contamination sources, and can be used as an economic alternative to chemical analysis when mapping heavy metal contamination in urban soil around the East Lake region, Wuhan, China. [source]

Removal of chromium (VI) through biosorption by the Pseudomonas spp. isolated from tannery effluent

JOURNAL OF BASIC MICROBIOLOGY, Issue 2 2008
Jatin Srivastava Dr.
Abstract Heavy metal contamination of the rivers is a world wide environmental problem and its removal is a great challenge. Kanpur and Unnao two closely located districts of Uttar Pradesh India are known for their leather industries. The tanneries release their treated effluent in the near by water ways containing Cr metal that eventually merges with the river Ganges. Untreated tannery effluent contains 2.673 ± 0.32 to 3.268 ± 0.73 mg l,1 Cr. Microbes were isolated, keeping the natural selection in the view, from the tannery effluent since microbes present in the effluent exposed to the various types of stresses and metal stress is one of them. Investigations include the exposure of higher concentrations of Cr(VI) 1.0 to 4.0 mg l,1 to the bacteria (presumably the Pseudomonas spp.) predominant on the agar plate. The short termed study (72 h) of biosorption showed significant reduction of metal in the media especially in the higher concentrations with a value from 1.0 ± 0.02, 2.0 ± 0.01, 3.0 ± 0, and 4.0 ± 0.09 at zero h to 0.873 ± 0.55, 1.840 ± 1.31, 2.780 ± 0.03 and 3.502 ± 0.68 at 72 h respectively. The biosorption of metal show in the present study that the naturally occurring microbes have enough potential to mitigate the excessive contamination of their surroundings and can be used to reduce the metal concentrations in aqueous solutions in a specific time frame. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Selection favours low hsp70 levels in chronically metal-stressed soil arthropods

JOURNAL OF EVOLUTIONARY BIOLOGY, Issue 4 2000
KÖhler
Thirty-eight populations of woodlice (Oniscus asellus, Porcellio scaber) and millipedes (Julus scandinavius) from 28 differently metal-polluted field sites were analysed for their 70-kDa stress protein (hsp70) level. Although ANOVA revealed significant dependence of the hsp70 level on the concentrations of water-soluble lead, cadmium and zinc and the soil pH, each of these parameters accounted for at most 18% of the intersite variability of the stress protein level only. A multivariate model based on multiple regression analysis explained more than 96% of hsp70 variance and revealed both the pollution history of a site (strong metal contamination for more than 70 years) and invertebrate species identity to act as the most important parameters. The model accounted for the observation that most of the populations from long-term polluted sites exhibited comparatively low stress protein levels in response to their own (contaminated) habitats. In contrast, isopods (O. asellus) from a control site were not able to maintain a low hsp70 level when they were exposed to either an artificial metal cocktail or soil taken from one of the contaminated field sites. They did not acclimatize to the exposure conditions within 3 months. We propose that selection of insensitive phenotypes in long-term polluted soils has taken place so as to minimize the stress protein level which, in turn, is indicative of high intracellular protein integrity. Long-term selection for a high hsp70 level to compensate for adverse metal impact was not observed, which suggests that such a strategy may trade off against other fitness consequences. In this context, insensitivity to metal stress involved increased selectivity in food choice and reduced variability in stress response. Multiple regression models showed species-specificity in those abiotic factors which determined (1) high hsp70 levels in sensitive populations as well as (2) low hsp70 levels in insensitive ones. Therefore, abiotic factors can be assigned to act as the main components of selection: lead and cadmium for J. scandinavius and O. asellus, zinc for P. scaber. [source]

SCANNING ELECTRON MICROSCOPY OBSERVATIONS OF DEFORMITIES IN SMALL PENNATE DIATOMS EXPOSED TO HIGH CADMIUM CONCENTRATIONS,

JOURNAL OF PHYCOLOGY, Issue 6 2008
Soizic Morin
Different types of malformations are likely to affect the morphology of diatoms when exposed to particularly unstable environmental conditions, the most easily identifiable being distortion of the whole frustule. In the present study, we investigated, by means of SEM, valve abnormalities induced by high cadmium contamination (100 ,g · L,1) in small pennate diatoms. Changes in the shape of Amphora pediculus (Kütz.) Grunow and anomalous sculpturing of the cell wall of many species, such as Encyonema minutum (Hilse) D. G. Mann, Mayamaea agrestris (Hust.) Lange-Bert., Gomphonema parvulum (Kütz.) Kütz., or Eolimna minima (Grunow) Lange-Bert., were observed, which were not, or almost not, noticeable in the LM. With consideration to current knowledge of diatom morphogenesis, metal uptake by the cell would induce, directly or indirectly, damage to many cytoplasmic components (e.g., microtubules, cytoskeleton, Golgi-derived vesicles) involved in the precisely organized silica deposition. This study confirms that many species, whatever their size, are likely to exhibit morphological abnormalities under cadmium stress, and that this indicator may be valuable for the biomonitoring of metal contamination, even if SEM observations are not necessary for routine studies. [source]

Assessment of element distribution and heavy metal contamination in Chilika Lake sediments (India)

LAKES & RESERVOIRS: RESEARCH AND MANAGEMENT, Issue 2 2009
D. W. Zachmann
Abstract Chilika Lake is situated on the Indian east coast. It is one of the largest lagoons in the world, with a unique assemblage of marine, brackish water and freshwater species. Due to the opening of new connections to the sea in the years 2000 and 2008, an environmental change is expected in the lagoon. The study gives an assessment of sediment contamination by heavy metals on the verge of this change (sampling campaign in 2000). Sediment samples from two surface levels (0,5 and 30,35 cm), and from depth profiles, were analysed for mineralogical composition, main and trace element concentrations, and element bonding forms. Background concentrations from a depth profile were also examined. The profile spans a time of ,13 500 years. Age determinations by radiocarbon dating and the 137Cs- and 210Pb-method were carried out. The composition of the surface sediments is generally uniform. The heavy metals exhibit slightly decreasing concentrations from NE to SW, thus indicating the supply of contaminants from the Mahanadi River. The anthropogenic portion of the heavy metal supply is mainly bound to Fe-oxide-hydroxides. Phosphorus is enriched in the sediments of the southern lake sector. Changes in element concentrations in the last 13 500 years have occurred mainly in two steps. The long-term variations exceed the anthropogenic changes caused by the Mahanadi River inputs. The very sensitive response of coastal area fabrics on climate changes also causes fast geogenic changes in element concentrations in sediments (similar grain sizes). This prevents the use of element concentrations from deep sediment horizons to define contaminations in those areas. [source]

Effects of heavy metal contamination from anthropogenic sources on Dasarahalli tank, India

LAKES & RESERVOIRS: RESEARCH AND MANAGEMENT, Issue 3 2007
H. Lokeshwari
Abstract This study examines the concentrations of various heavy metals, and their distribution in a hyper-eutrophic urban Dasarahalli tank system, which is being polluted from industrial, domestic and sewage effluents. The concentration of iron (Fe), zinc (Zn), copper (Cu), nickel (Ni), chromium (Cr), lead (Pb) and cadmium (Cd) in water, plant (Alternanthera philoxeroides) and sediment samples was determined. The water-soluble (bioavailable) fractions of heavy metals correlated positively with their total concentration, exhibiting the following sequence of bioavailability: Zn > Cd > Ni > Fe > Cu > Pb > Cr. A. philoxeroides exhibited a maximum bioaccumulation factor for cadmium (3913). The mean values of all types of collected samples were correlated with the corresponding mean values in a control tank (Vasanthapura tank). The sequence of the order of the concentrations of the metals in water, plant and sediment samples exhibiting higher values than those observed in the control tank was as follows: Cr > Ni > Pb > Cu > Fe > Zn, Cd > Cr > Fe , Zn , Cu , Pb and Pb > Cu , Cr > Zn , Ni > Fe, respectively. The geoaccumulation indices of the heavy metals revealed that the tank is moderately contaminated. As A. philoxeroides is extensively used for human consumption and also as cattle fodder, there is a growing health risk that these metals could find their way into the human food chain. [source]

Shape-selective synthesis of II,VI semiconductor nanowires

PHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 13 2006
A. Fasoli
Abstract Polar II,VI semiconductors can nucleate in complex shapes ranging from nanowires to nanoribbons, nanosaws and multipods. Here we demonstrate the deterministic and fully reproducible shape-selective growth of several morphologies of CdSe and ZnTe nanocrystals by a steady-state vapour transport process. A simple pressure-based precursor-flow shutter excludes any effects of temperature ramping, ensuring reproducible shape selectivity for each set of deposition parameters. Once thermal gradients are eliminated, we show that the transition from one nanocrystal shape to another is controlled just by the interplay of precursor impinging on the substrate (ruled by the powder temperature TP) and sample surface kinetics (ruled by the sample temperature TS). Furthermore, a regime is found where seeded, epitaxial growth of CdSe nanorods becomes dominant over the conventional catalyst-assisted nucleation. This allows the fabrication of vertical nanorod arrays free of any metal contamination. Seeded growth of branched and tetrapod-like nanocrystals is also possible by further optimisation of the growth parameters. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Chemical natures and distributions of metal impurities in multicrystalline silicon materials

PROGRESS IN PHOTOVOLTAICS: RESEARCH & APPLICATIONS, Issue 6 2006
T. Buonassisi
Abstract We present a comprehensive summary of our observations of metal-rich particles in multicrystalline silicon (mc-Si) solar cell materials from multiple vendors, including directionally-solidified ingot-grown, sheet, and ribbon, as well as multicrystalline float zone materials contaminated during growth. In each material, the elemental nature, chemical states, and distributions of metal-rich particles are assessed by synchrotron-based analytical x-ray microprobe techniques. Certain universal physical principles appear to govern the behavior of metals in nearly all materials: (a) Two types of metal-rich particles can be observed (metal silicide nanoprecipitates and metal-rich inclusions up to tens of microns in size, frequently oxidized), (b) spatial distributions of individual elements strongly depend on their solubility and diffusivity, and (c) strong interactions exist between metals and certain types of structural defects. Differences in the distribution and elemental nature of metal contamination between different mc-Si materials can largely be explained by variations in crystal growth parameters, structural defect types, and contamination sources. Copyright © 2006 John Wiley & Sons, Ltd. [source]

Trends in metals in urban and reference lake sediments across the United States, 1970 to 2001

ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 7 2006
Barbara J. Mahler
Abstract Trends in metals concentrations in sediment cores from 35 reservoirs and lakes in urban and reference settings were analyzed to determine the effects of three decades of legislation, regulation, and changing demographics and industrial practices in the United States on concentrations of metals in the environment. Decreasing trends outnumber increasing trends for all seven metals analyzed (Cd, Cr, Cu, Pb, Hg, Ni, and Zn). The most consistent trends are for Pb and Cr: For Pb, 83% of the lakes have decreasing trends and 6% have increasing trends; for Cr, 54% of the lakes have decreasing trends and none have increasing trends. Mass accumulation rates of metals in cores, adjusted for background concentrations, decrease from the 1970s to the 1990s, with median changes ranging from ,46% (Pb) to ,3% (Hg and Zn). The largest decreases are from lakes in dense urban watersheds where the overall metals contamination in recently deposited sediments has decreased to one-half its 1970s median value. However, anthropogenic mass accumulation rates in dense urban lakes remain elevated over those in lakes in undeveloped watersheds, in some cases by as much as two orders of magnitude (Cr, Cu, and Zn), indicating that urban fluvial source signals can overwhelm those from regional atmospheric sources. [source]