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Results for “Metals, Heavy”

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PubMed1993

Isolation of a candidate gene for Menkes disease that encodes a potential heavy metal binding protein.

Menkes disease is a lethal-X linked recessive disorder associated with copper metabolism disturbance. We have recently mapped two chromosome breakpoints related to this disease in a 1 megabase yeast artificial chromosome contig at Xq13.3. We now report the construction of a phage contig and the isolation of candidate partial cDNAs for the Menkes disease gene. The candidate gene expresses an 8 kb message in all investigated tissues, and deletions were detected in 16% of 100 unrelated Menkes patients. The deduced partial protein sequence shared the GMTCXXC motif with bacterial metal resistance operons, suggesting a potential heavy metal binding protein. These findings should lead to more accurate prenatal diagnosis of this severe disease and a better understanding of the cellular homeostasis of essential heavy metals.

Adenosine Triphosphatases↗

PubMed1994

Effects of heavy metals on motility and gravitactic orientation of the flagellate, Euglena gracilis.

The effects of copper, mercury, cadmium and lead on the gravitactic orientation of the photosynthetic flagellate Euglena gracilis were investigated. The first two heavy metals reverse the direction of downward swimming (positive gravitaxis) in young cultures (up to 8 days) to an upward swimming (negative gravitaxis); cadmium produced a less pronounced effect. Higher concentrations of heavy metals decrease the precision of orientation as compared to the control due to frequent deviations of the cells from straight paths. Higher concentrations also decrease the swimming velocity of the populations. When the cells were growing in the presence of the heavy metal, copper was effective at > or = 50 microM, cadmium at > or = 3 microM and mercury at > or = 1 microM. Since lead formed insoluble precipitations with the acetate in the growth medium it was tested after the cells were transferred into Tris buffer. Under these conditions lead did not affect the direction of movement or the precision of orientation up to a concentration of 300 microM in the time up to 24 h after the addition of the heavy metal. However, high concentrations of lead strongly decreased the swimming speed of the cells, which was partially reversed with time.

Animals↗

PubMed2003

Assessment of heavy metal contamination of seawater and marine limpet, Patella vulgata L., from Northwest Spain.

In the present work, both seawater and limpets (Patella vulgata L.) were collected from different sampling points in the Vigo estuary area (Galicia, NW Spain) and their heavy metal concentrations (Zn, Cd, Pb, Cu) were determined by means of a voltammetric technique. The results showed a direct relationship between the heavy metal levels in seawater and the content in biological samples, especially those obtained from limpet soft tissues, directly related to the increasing importance of anthropogenic environmental contamination. Heavy metal concentrations were usually higher in soft tissues than in shell, with a maximum difference corresponding to Cd and Zn (average of 93.6 and 86 folds, respectively). As expected, heavy metal content was higher in animal samples situated in inner part of the estuary zone, except for cadmium content in soft tissues, where a maximum of 5.62 ppm was quantified in limpet soft tissues collected next to the open sea area. Statistical analysis allowed the establishment of a clear relationship between Zn and Cd content in both shells and soft tissues from limpet, and especially between Zn and Cu in soft tissues (p < 0.001).

Animals↗

PubMed2004

Estimation of the mass-balance of selected metals in four sanitary landfills in Western Norway, with emphasis on the heavy metal content of the deposited waste and the leachate.

A worst-case simulation of the mass-balance for metals in the waste deposited during 1 year and the levels of cadmium (Cd), lead (Pb), mercury (Hg), chromium (Cr) and iron (Fe) in the leachate was calculated for four sanitary landfills in Western Norway. Estimates of the levels of metal content in mixed municipal solid waste (MSW) were found by using recent literature values calculated in a mass-balance study at a Norwegian waste incinerator plant. Leachate from the landfills were sampled and analyzed monthly during 1 year, and from these measurements the total annual discharge of the selected metals through the leachate was determined. The levels of the measured heavy metals in the leachate were low. For Cd less than 0.06%, for Pb less than 0.01% and for Hg less than 0.02% of the estimated year's deposited mass of metals were leached from the landfills during the year of investigation. The high retention of these metals are most likely due to sulfide precipitation, but also due to the immobile condition of the metals in their original deposited solid state (plastics, ceramics, etc.). The percentage of Cr leached was relatively higher, but less than 1.0% per year. The mass balance of Fe suggests that this element is more mobile under the prevailing conditions. The percentage of Fe leached varied and was estimated to be between 1.9% and 18%. The present study clearly supports the theory that MSW only to a small extent will lead to discharge of metals if deposited at well-constructed sanitary landfills with top layers.

Chromium↗

PubMedDate not supplied

MRI observation of heavy metal transport in aquifer matrices down to sub-mg quantities.

In this contribution, we report results from MRI studies of the propagation of heavy metal ions through columns packed with sandy aquifer materials. Both sorption of low concentrations of heavy metal ions from water flowing through the column and the formation of sorption traces produced from initially localized higher concentrations of heavy metal ions, and the remobilisation of adsorbed ions with time and changing hydrochemical conditions were studied. Multislice spin-echo and FLASH techniques were used for the imaging experiments. Advantages and problems of the different imaging protocols for the study of aquifer materials are discussed.

Adsorption↗

PubMed2006

Reproductive effects of heavy metal accumulation on breeding feral pigeons (Columba livia).

To investigate the effects of heavy metal accumulations on breeding birds, we compared the egg size, eggshell thickness and some reproductive parameters in feral pigeon populations collected from Seoul and Ansan colonies. The results showed that concentrations of Pb in bone and Cd in kidney of adult pigeons in Seoul were three times higher than in Ansan colony. Significant positive correlation was also observed between Pb and Zn in bone and Cd and Zn in kidney of adult pigeons from Seoul, but not Ansan. This indicates that pigeons at Seoul may be affected more by the toxic Pb and Cd exposure in the environment rather than those at Ansan because of the antagonistic action of Zn against Pb and Cd toxicity. No significant difference was observed in egg characteristics (egg length, width and shell thickness), clutch size (number of eggs per clutch), incubation periods and hatchability of squabs between the two study sites. Although no significant difference was observed, body weight, and primary wing, bill and tarsus lengths of nestlings from Seoul which is more polluted were rather smaller than those from Ansan. Nestlings at Seoul fledged significantly later than at the less polluted site (Ansan). We also observed significantly lower fledging success at Seoul than Ansan colony. Elevated metal exposure may thus result in decreasing growth rate in pigeon nestlings resulting in fledging length and fledging success. Our results suggest a possible effect of heavy metal bioaccumulation on breeding of feral pigeons.

Animals↗

PubMed2001

Heavy metal contents in the Delft canal sediments and suspended solids of the River Rhine: multivariate analysis for source tracing.

We have analyzed heavy metal contents in the sediments of three Delft inner city canals (Rietveld, Oude Delft and Zuiderstraat) and compared them with the heavy metal contents in the River Rhine suspended solids. All the data were examined by multivariate analysis in order to explain the behavior and sources of each metal. Correlation coefficient matrices were studied in order to find an internal structure and assist in identification of pollutant sources. The good correlation among almost all the heavy metals (except Pb) indicates that there are common sources or at least one major source for them. Based on the factor analysis technique, principal components score plots were obtained to cluster the data (63 samples from the Delft canals and 10 from the River Rhine) and describe their different characteristics. It was found in the plots that the data from the River Rhine clustered together with 2 out of the 3 Delft stations (Rietveld, Oude Delft). This supports the view that the River Rhine is an important external micropollutant source for the Delft inner city canals. The third station (Zuiderstraat) showed much higher pollution levels than the other Delft canals; apparently it has been influenced not only by the River Rhine but also by internal pollutant inputs such as metal corrosion and paints from local boathouses.

Cities↗

PubMed1990

[Distribution pattern of chemicals in surface waters as a reflexion of entry pattern--heavy metals].

The concentrations of the heavy metals lead, cadmium and mercury were measured in surface water samples of an industrialized city and its surroundings. All but one value of Cd (particular) were less than 0.5 microgram l-1, 30% of the lead (particular) values were less than 0.5 microgram l-1, 70% 0.5 ... 10 micrograms l-1, 86% of the total mercury less than 0.1 and 14% 0.1 ... 0.5 microgram l-1. By applying the differential-diagnostic assessment method it could be found that the highest values were found in the vicinity of a metal-using factory. On a sampling point near such an enterprise the part of particularly bound lead was very low, that means a recent input, whereas on another sampling point with a high total lead level 95% were particularly bound which refers to a continuous input.

Cadmium↗

PubMed2006

The risk assessment of heavy metals in the ecosystem of urban creeks.

This paper is focused on risk assessment of heavy metals in freshwater ecosystems of urban creeks. The paper reports changes in an aquatic ecosystem leading to remobilization of heavy metals and consequently to changes of bioavailability. Concentrations of metals in water, bed sediment and benthic organisms from several small urban streams are monitored and evaluated. In the small urban streams studied copper, zinc and lead were determined as the most significant hazard metals. Although concentrations of these metals in water are very low (often below the detection limit of analytical equipment), concentrations in sediment were found in risky levels mainly in sampling sites affected by CSOs and SSOs from industrial and heavy traffic areas. The benthic organisms showed different ability to accumulate heavy metals (HM). The feeding type collector gatherer had in most cases the highest body concentration of HM and the predator species cumulate, to a high level, only zinc which has a high tendency to release from sediment, hence it is the most bio-available. The collector-filterer had mostly low values. The differences among species are due to the different feeding habits of each trophic level.

Animals↗

PubMed2006

Distribution of heavy metals in freshwater ecosystem of a small stream impacted by urban drainage.

This paper focuses on the study of heavy metals' remobilisation possibilities and changes of distribution coefficients leading to remobilisation in a stream as a result of changing conditions caused by urban drainage. The paper also reports consequent changes of bioaccumulation coefficient for different species of the benthic community, which seems to be the best indicator of aquatic community quality in small urban streams. The paper presents results obtained during field monitoring as well as results obtained during laboratory experiment. The field monitoring identified in the study area (the Botic Creek) three heavy metals (Cu, Zn and Pb), which are the main sources of toxicological risk in this area. Based on the monitoring, these elements were used for laboratory experiment, where their behaviour during changing conditions was studied. The experiment shows that changing conditions in the stream, caused by urban drainage, significantly impact the fate of heavy metals in aquatic ecosystems and that these elements have different preferences to bind to a particular geochemical fraction of sediment, which consequently means different bioavailability.

Cities↗

PubMed2001

Small-scale spatial and temporal variance in the concentration of heavy metals in aquatic sediments: a review and some new concepts.

Uncertainty associated with data derived by the analyses of heavy metals in aquatic sediment is due to variance produced in the laboratory (precision), plus 'natural', small-scale spatial variance, (or field variance) at the sampling site. Precision is easily determined and is usually reported in contaminant studies, but field variance is poorly understood and seldom documented. It is important to have an understanding of the field variance because if small-scale spatial variance in the concentration of heavy metals is excessive, regional trends may be limited value. Similarly, if temporal change is large, the results of single synoptic surveys may be questionable and the ability to demonstrate anthropogenic contributions over time will be difficult. However, it is evident from the literature that the information needed to address problems of spatial and temporal variance in the field is beyond the resources of most researchers. Analytical precision of about 5% relative standard deviation (RSD) for heavy metal analysis is typical of a well-managed laboratory. Many studies of small-scale spatial variability made during the current investigation indicate that field variance is related to ambient energy and to the type of sedimentological environment. Total variance (analytical plus field variance) is approximately 10% RSD (mean for a suite of nine trace elements) for depositional parts of estuaries and the marine environment, but increases to about 20-35% RSD for the more dynamic parts of the estuarine environment and the fluvial system. Repeated sampling over periods of up to 7 years undertaken during the present study, indicate a similar order of magnitude for temporal variability in these sedimentological environments. A proposed scheme to provide information on field variance is to undertake small-scale spatial and temporal studies in discrete sedimentological environments in the study area after sediment sampling and characterisation has been completed. The comparatively large proportion of total variance associated with small-scale spatial and temporal variability in the field questions the often excessive cost and effort made in attempting minor reductions in analytical precision in contaminant investigations.

Ecosystem↗

PubMed2003

Metallothionein induction in the RTH-149 cell line as an indicator for heavy metal bioavailability in a brackish environment: assessment by RT-competitive PCR.

Estuarine and marine near-shore environments are often subjected to heavy metal pollution. We establish a bioassay using the quantitative evaluation of metallothionein (MT) transcript in the fish hepatoma cell line, RTH-149, as a tool for detecting heavy metal pollution in brackish-marine water containing other pollutants in addition to heavy metals. RT-competitive polymerase chain reaction was used for the quantitative evaluation of the transcript in absolute units. Cadmium was used as a model pollutant to optimize two parameters of the assay: exposure periods (24, 96, 144 h) and salinity (0%, 25%, 50%, 75%, 100% sea water). Results revealed that salinity at or below 25% sea water at an exposure period of 144 h are the preferable conditions for detecting MT mRNA levels for in vitro assays employed on water samples from highly polluted brackish habitats.

Animals↗

PubMed1997

Heavy metal concentrations in adult acanthocephalans and cestodes compared to their fish hosts and to established free-living bioindicators.

Intestinal helminths of fish caught from freshwater and brackish water biotopes throughout Europe were analysed by electrothermal atomic absorption spectrometry for their heavy metal (Pb and Cd) levels. The metal concentrations of the parasites were compared to those of different organs (muscle, liver, intestine) of the fish hosts and to those detected in the whole bodies of the respective intermediate hosts. The three acanthocephalan species analysed contained very high amounts of Pb and Cd. The lead level of Pomphorhynchus laevis was up to 2700 times higher and the cadmium concentration was approximately 500 times higher than the muscle of chub, its host. Concurrent analysis of larval acanthocephalans in the crustacean intermediate host indicated that the bioconcentration of heavy metals by these parasites occurs only in the final host. In two species of cestodes accumulation of metals was also recorded although the degree of bioconcentration was somewhat lower. Nevertheless, Monobothrium wageneri contained 75 times more Pb and 43 times more Cd than the muscle of its host, the tench. In contrast, no bioconcentration of heavy metals was detected in the swimbladder nematode Anguillicola crassus. It contained less lead than the muscle of its final host, the eel. In one biotope the concentration of 18 elements was compared between the whole soft tissues of the zebra mussel, Dreissena polymorpha, the parasite Acanthocephalus lucii and its final host, perch. The acanthocephalan accumulated most of the elements to considerably higher concentrations than the zebra mussel, which has been considered an effective bioindicator of heavy metals. The sessile nature of the zebra mussel may allow a better identification of small-scale local differences in environmental heavy metal contamination. However, acanthocephalan parasites will provide an ecologically-important index of average exposure of their mobile fish host to biologically-available metals within its natural range.

Acanthocephala↗

PubMed2006

Associations between shell strength, shell morphology and heavy metals in the land snail Cepaea nemoralis (Gastropoda, Helicidae).

In snails there is an intimate relation between shell size, thickness, strength and calcium content that may be influenced by environmental factors such as predation and heavy metal pollution. The snail Cepaea nemoralis shows variability for shell colour and banding pattern, and frequencies of colour morphs are highly variable in natural populations. We used C. nemoralis to investigate (i) the relations between shell morphology, shell Ca and heavy metal content (Cd, Cr, Pb, Zn), and shell strength, (ii) differences in shell morphology and shell strength among localities and yellow and pink shells and (iii) whether snails from polluted sites show increased levels of heavy metals in their shell. Larger shells were heavier, thicker, needed a higher force to be crushed but did not have a higher Ca concentration. Cd and Zn concentrations were higher in shells from polluted plots compared to shells from unpolluted plots but Ca levels in the shell were comparable among plots. Zn concentration was negatively correlated with shell traits. Although there was substantial variation in shell strength, thickness and dry weight among localities, none of the shell traits differed between individuals from polluted and reference plots nor between colour morphs. Our results suggest that the effect of heavy metal pollution on shell strength and morphology is limited in the investigated populations.

Animals↗

PubMed2001

Cell surface-engineered yeast displaying a histidine oligopeptide (hexa-His) has enhanced adsorption of and tolerance to heavy metal ions.

A histidine oligopeptide (hexa-His) with the ability to chelate divalent heavy metal ions was displayed on the yeast cell surface for the purpose of enhanced adsorption of heavy metal ions. We genetically fused a hexa-His-encoding gene with the gene encoding the C-terminal half of alpha-agglutinin that includes a glycosylphosphatidylinositol anchor attachment signal sequence and attached the hexa-His peptide on the cell wall of Saccharomyces cerevisiae. This surface-engineered yeast adsorbed three to eight times more copper ions than the parent strain and was more resistant to copper (4 mM) than the parent (below 1 mM at pH 7.8). It was possible to recover about a half of the copper ions adsorbed by whole cells with EDTA treatment without disintegrating the cells. Thus, we succeeded in constructing a novel yeast cell with both tolerance to toxic contaminants and enhanced adsorption of metal ions onto the cell surface.

Adsorption↗

PubMed2006

Distribution and accumulation of heavy metals in the sediments of Kaohsiung Harbor, Taiwan.

The distribution, enrichment, and accumulation of heavy metals in the sediments, especially those at the vicinity of tributary estuaries of Kaohsiung Harbor, Taiwan were investigated. Sediment samples from six locations in the Kaohsiung Harbor were collected quarterly in the period from 2002 to 2005 and characterized for metal content (e.g., Hg, Pb, Cd, Cr, Cu, Zn and Al), water content, organic matter, total nitrogen, total phosphorous, total grease, and grain size. Results showed that metal concentrations varied from 0.58 mg kg(-1) for Cd to 596 mg kg(-1) for Zn. Metal concentrations at the vicinity of river mouths were higher than those at other locations. All heavy metals studied, except Cr, had relatively high enrichment factors and geo-accumulation indices in the estuaries. Moreover, metal concentrations correlated closely to the physical-chemical properties of the sediments, which strongly suggested the influence of industrial and municipal wastewaters discharged from the neighboring industrial parks and river basins. Results would help develop strategies for pollution control and sediment remediation of Kaohsiung Harbor.

Environmental Monitoring↗

PubMedDate not supplied

[Search of heavy metals biosorbents among yeasts of different taxonomic groups].

The use of microbial cells as heavy metal biosorbents is a potential alternative for the existing methods of the environment treatment for pollution by these metals. Yeast may be successfully used in the metals sorption. An agar-plate screening method was used for rapid isolation of metal-accumulating strains of yeast and preliminary estimation of their biosorption capacity. The capacity to accumulate heavy metals, such as copper, zinc, lead, chrome and cobalt was estimated in 68 pigmented and pigmentless yeast strains isolated from different sources. The best capacity of copper and zinc accumulation was shown by pink-coloured Rhodotorula mucilaginosa, Rhodotorula aurantiaca, Rhodotorula glutinis and pigmentless strains of the yeast Candida krusei, Williopsis california.

Biodegradation, Environmental↗

PubMed2002

Toxicity and heavy metal contamination of surficial sediments from the Bay of Thessaloniki (Northwestern Aegean Sea) Greece.

Surficial sediments (the fraction < 2000 microm) from the Bay of Thessaloniki, in the Northwestern Aegean Sea, Greece were examined for heavy metal and organic carbon contents, as well as for acute LUMIStox toxicity of pore waters (PWs), wet sediment elutriates (WSEs) and dry sediment elutriates (DSEs) obtained from the solid material remaining after PW extraction. WSEs where not toxic. EC20/50 values could be measured in some DSE and PW samples. In all sediment samples, the DSE toxicity was greater than the corresponding PW toxicity. Sediment concentrations of total and labile Cd, Pb, Cu, Cr, Zn, Mn, Ni and Fe were determined and evaluated in relation to sediment quality guidelines. Pollution levels ranged from low to high for certain metals. A misfit between sediment toxicities calculated from heavy metal concentrations and those biologically measured was observed. Toxicity values were in general poorly correlated with sediment's heavy metal or organic carbon content. As significant correlation was however found between the DSE toxicity with total Ni and labile Fe, as well as for the PW toxicity with total Ni, labile Fe and labile Cr.

Carbon↗