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PubMed2001

Heavy metals affect the circulating haemocyte number in the shrimp Palaemon elegans.

Environmental contamination by heavy metals produced by either anthropogenic or natural activities represents a threat to many species of aquatic animals worldwide. This study investigates the effect of short-term (96 h) exposure to dissolved heavy metals on the number of circulating haemocytes in the shrimp, Palaemon elegans (Rathke). Changes in haemocyte counts were determined in relation to time of exposure and with heavy metal concentration, relating the results to toxicity. It was found that immersion in artificial seawater containing Hg, Cd, Cu, Cr, Zn or Pb caused a decrease in the haemocyte count during the first 8 h exposure, although the haemocyte number returned to the initial (time 0) levels over the following 16 h immersion. In each case, the decrease in circulating haemocyte count induced by these metals was significantly different from the controls. The greatest decrease in haemocyte numbers (haemocytopenia) was induced by Pb, followed, in descending order, by Zn, Hg, Cr, Cu and Cd. The lethal level of haemocytopenia for the shrimps, defined as the number of haemocytes ml remaining in moribund animals (i.e. threshold of mortality) was found to be significantly lower than the levels tolerated by surviving shrimps (i.e. the limit of survival). The percentage of haemocytes remaining in the circulation at the threshold of mortality as a function of the number at time 0 was 56.6 +/- 8.8%. By contrast, the equivalent value for the threshold of survival was 63.7 +/- 12.4%. Importantly, the percentage decrease in haemocyte counts tolerated by P. elegans appears to vary with the metal. Animals treated with Pb or Zn survived with a lower number of circulating haemocytes than animals exposed to the other heavy metals.

Animals↗

PubMed2003

Modeling heavy metal uptake by sludge particulates in the presence of dissolved organic matter.

The uptake of the seven heavy metal ions Cd(II), Co(II), Cr(III), Cu(II), Ni(II), Pb(II), and Zn(II) by sludge particulates in single-metal systems was investigated. Results showed that under acidic and neutral pH conditions, the uptake of all heavy metals by sludge particulates increases with the increase of pH. However, in the alkaline pH region, the uptake of Cu(II), Ni(II), and Co(II) decreases with the increase of pH, primarily due to the high dissolved organic matter (DOM) concentration in high pH conditions. Based on chemical reactions among heavy metal, sludge solids, and DOM, a mathematical model describing metal uptake as functions of DOM and pH was developed. The stability constants of metal-sludge and metal-DOM complexes can be determined using this model in conjunction with experimental metal uptake data. Results showed that, for the secondary sludge sample collected from Baltimore Back River Wastewater Treatment plant on March 1997, the stability constants of Cu(II)-sludge complex (log K(S)) and Cu(II)-DOM complex (log K(L)) are 5.3+/-0.2 and 4.7+/-0.3, respectively; for Ni(II), they are 4.0+/-0.2 and 3.9+/-0.2, respectively. Results also showed that under neutral and low pH conditions (pH<8), the DOM effects on metal uptake for all heavy metals are insignificant. Therefore, the DOM term in the model can be ignored. Results showed that, for the secondary sludge sample collected from Baltimore Back River Wastewater Treatment plant on December 1996, the estimated log K(S) values of metal-sludge complexes for Cd(II), Co(II), Cr(III), Cu(II), Ni(II), Pb(II), and Zn(II) are, respectively, 3.6+/-0.2, 3.0+/-0.1, 5.5+/-0.1, 4.8+/-0.1, 3.1+/-0.1, 5.1+/-0.1, and 4.4+/-0.3.

Hydrogen-Ion Concentration↗

PubMed1996

External quality assessment scheme in Belgium. Heavy metal analyses.

An external quality assessment scheme for heavy metal analyses has been implemented in Belgium (quality control in Belgium, QCB) by the Epidemiology Unit of the Institute of Hygiene and Epidemiology since 1993. Aims of the scheme are to improve laboratories performances by means of interlaboratory comparisons and to provide national authority with information about the dispersion of results for heavy metal analyses in Belgium. The analytes included in the QCB are lead, cadmium and selenium in blood. Control samples are in-house prepared from human blood, spiked with appropriate amounts of Pb, Cd and Se. Four exercises are performed every year and participants receive three samples to analyze. Target values are calculated for each element from the regression lines obtained by plotting the results of a reference laboratory against the added amounts. The QCB does not yet include acceptability criteria of the results and no measures are taken against poor performers at this stage, although advice is available by personal contacts with the organisers.

Belgium↗

PubMed2002

[Study of image quality (contrast) and reduction of patient dose by using heavy metal filters].

We studied image quality (contrast) and patient dose reduction using heavy metal filters in lumbar spine and abdomen x-ray examination. Heavy metal filters used in this study are gadolinium, holmium and ytterbium and these combinations. These filters have k-absorption edge in the range from 50 to 70 keV. Image quality and patient dose in 70-90 kV tube voltage with heavy metal filters were compared with 80 kV tube voltage without filter. Image quality was improved in four percent and patient dose could be reduced by 30%. However, tube loading increased from 1.6 to 2.2 times. It was found that the best filter choices gave better image and reduced patient dose compared to without filter.

Filtration↗

PubMed1990

Effects of heavy metal on rat liver microsomal Ca2(+)-ATPase and Ca2+ sequestering. Relation to SH groups.

In isolated hepatic microsomal vesicles the heavy metals Cd2+, Cu2+, and Zn2+ inhibit Ca2+ uptake and evoke a prompt efflux of Ca2+ from preloaded vesicles in a dose-dependent manner. N-Ethylmaleimide also inhibits Ca2+ uptake and causes Ca2+ release, but it is less effective in these respects than the heavy metals. Measurement of mannose-6-phosphatase activity indicate that the heavy metal-induced Ca2+ efflux is not caused by a general increase in membrane permeability. Heavy metals also inhibit the Ca2(+)-ATPase activity and the formation of the phosphorylated intermediate of the enzyme. In contrast, the sulfhydryl modifying reagent, N-ethylmaleimide inhibits the Ca2(+)-ATPase activity while it has a relatively small effect on Ca2+ release. Thus, the effects of these agents on Ca2+ sequestering and Ca2(+)-ATPase activity are not strictly proportional. The sulfhydryl group reducing agent dithiothreitol protects the microsomes from the effects of heavy metals, while glutathione is less protective. Addition of vanadate to vesicles, at a concentration which completely blocked the activity of the Ca2(+)-ATPase, resulted in a small and slow release of the accumulated Ca2+. Subsequent additions of heavy metals evoked a massive Ca2+ release. Thus, the effects of heavy metals on Ca2+ efflux cannot be due entirely to their inhibition of the Ca2+ pump. The heavy metal-induced Ca2+ efflux is not inhibited either by ruthenium red or tetracaine.

Animals↗

PubMed2001

Influence of heavy metals on the accumulation of trimethylglycine, putrescine and spermine in food plants.

Increased contents of cadmium (Cd), lead (Pb), zinc (Zn) and other heavy metals in barley plants enhanced the accumulation of trimethylglycine (betaine), putrescine and spermine. Higher contents of heavy metals in barley were caused by soil enrichment with heavy metals and by soil salinity. The highest accumulation of spermine and betaine (increase 3-fold or 5-fold in comparison to untreated soil substrates) was obtained at the highest concentration of heavy metals in plants. Consequently the betaine-N/protein-N-ratio and the spermine-N/protein-N-quotient increased 3-fold in plants with high heavy metal contents. The biomass formation was not changed significantly by the different experimental treatments.

Betaine↗

PubMed2005

Heavy metal concentrations in redeveloping soil of mine spoil under plantations of certain native woody species in dry tropical environment, India.

Total concentration of heavy metals (Cd, Cr, Cu, Fe, Pb, Ni, Mn and Zn) was estimated in the redeveloping soil of mine spoil under 5-yr old plantations of four woody species namely: Albizia lebbeck, Albizia procera, Tectona grandis and Dendrocalamus strictus. The data recorded in the present study were compared with other unplanted coal mine spoil colliery, which was around to the study site and adjoining area of dry tropical forest. Among all the heavy metals, the maximum concentration was found for Fe and minimum for Cd. However, among all four species, total concentrations of these heavy metals were recorded maximally in the plantation plots of T. grandis except for Fe, while minimally in A. lebbeck except for Zn, whereas, the maximum concentration of Fe and Zn was in the plantation plots of D. strictus and A. procera. Statistical analysis revealed significant differences due to species for all the heavy metals except Cu. Among four species, A. lebbeck, A. procera and D. strictus showed more efficient for reducing heavy metal concentrations whereas T. grandis was not more effective to reduce heavy metal concentrations in redeveloping soil of mine spoil.

Agriculture↗

PubMed1999

Ecotoxicological hazard and risk assessment of heavy metal contents in agricultural soils of central Germany.

Heavy metal content of agricultural topsoils has been experimentally determined at 14 areas in the German Leipzig-Halle-Bitterfeld region covering ca. 3700 km2. For most of the locations and elements, the contamination levels are comparable to those of other agricultural sites in Germany and Europe. Application of a sequential extraction technique revealed relatively low contamination levels in the mobile fractions, which indicates a correspondingly low degree of bioavailability of the heavy metals under the current milieu conditions. In contrast, acidification of the soil due to a drastic decrease in the deposition of calciferous fly ash would lead to a significantly increased ecotoxicological hazard potential, as is analyzed by a probabilistic distribution method that quantifies the overlap of normalized exposure and effect data. The discussion includes recommendations for further improvement of risk assessment schemes addressing soil contamination.

Acid Rain↗

PubMed2001

Comparison of microbial and meiofaunal community analyses for determining impact of heavy metal contamination.

The impact of long-term heavy metal contamination on soil communities was assessed by a number of methods. These included plate counts of culturable bacteria, community level physiological profiling (CLPP) by analysis of the utilization of multiple carbon sources in BIOLOG plates, community fatty acid methyl ester (C-FAME) profiling and dehydrogenase enzyme activity measurements. These approaches were complemented with microscopic assessments of the diversity of the nematode community. Samples from two sites with different histories of heavy-metal input were assessed. Major differences in microbial and meiofaunal parameters were observed both between and within the sites. There was a large degree of congruence between each of the microbiological approaches. In particular, one sample appeared to be distinguished by a reduction in culturable bacteria (especially pseudomonads), limited response to carbon sources in CLPP, and major differences in extracted fatty acid profiles. The use of multivariate analysis to examine the relationship between microbial and physicochemical measurements revealed that CLPP and plate counts were useful for determining the gross effect of metals on soil microbial communities, whereas proportions of metal-resistant bacteria and dehydrogenase activity differentiated between the two sites. Copper and zinc concentrations and pH all showed significant correlation with the microbial parameters. Nematode community structure was affected to a greater extent by soil pH than by metal content, but the within-site rankings were the same as those achieved for microbiological analyses. The use of these methods for field evaluation of the impact of industrial pollution may be possible provided care is taken when interpreting the data.

Animals↗

PubMed1979

Influence of the acute intoxication with salts of some heavy metals on hexobarbital sleep and hexobarbital metabolism.

The effect of acute intoxication with salts of ten heavy metals on hexobarbital sleep and the dependence of this effect on the time of application and the dose of the heavy metal are studied in experiments on male albino rats. Two hours after subcutaneous injection of toxic doses, only cobalt nitrate significantly prolongs hexobarbital sleep. Significant prolongation of the sleep is observed at the 24th hour in intoxication with CuSO4, CdSO4, Co(NO3)2, Pb(CH3COO)2, ZnSO4, NiSO4, while As2O3, HgCl2, Bi(NO3)2 and SnCl2 do not change it. All heavy metals (with the exception of NiSO4) prolong significantly hexobarbital sleep 96 hours after the intoxication. At the 24th hour after intoxication with salts of heavy metals, the hexobarbital level in the blood serum at the 30th min after its administration is significantly higher for Co(NO3)2, CdSO4, NiSO4, and it tends to be higher for CuSO4 and Pb(CH3COO)2. This, together with the significant inhibition of the hexobarbital-oxidizing enzyme system in the case of Cu, Co, Cd and Pb, suggests that in the case of these heavy metals potentiation of the hexobarbital sleep is largely due to inhibition of the hexobarbital metabolism. No significant prolongation of hexobarbital sleep or changes in hexobarbital metabolism are found in intoxication with Hg, As, Bi and Sn salts. The definitely lower hexobarbital level in the blood serum and brain at the waking moment, as well as the lower threshold hypnotic doses, suggest the interference of pharmacodynamic mechanisms at the level of the central nervous system in the prolongation of hexobarbital sleep after acute intoxication with CuSO4, CdSO4 and NiSO4.

Acute Disease↗

PubMedDate not supplied

Chemical analyses of heavy metal contamination in sediments of the Venice Lagoon and toxicological implications.

Heavy metals are extracted from sediments using 1 M HCl; then, solutions are neutralised with 1 M NaOH, to fit the conditions suitable for the Vibrio Fischeri test. In the neutralised solutions different percentages of initial metal concentration are present, depending on the individual solubilities. The chemical investigation of the metal fraction extracted from the sediment with this procedure and the different metal bioavailability depending on the presence of natural complexing agents are the subject of this work. The results obtained confirm the good agreement between heavy metal fraction extracted using 1 M HCl and the anthropogenic component in the sediment. The use of voltammetric techniques, and the addition of low molecular weight humic acids into extracts show the ability of natural complexing agents in affecting heavy metal bioavailability and toxicity.

Biological Assay↗

PubMed2006

Occurrence of platinum and additional traffic related heavy metals in sediments and biota.

Non-point sources play an important role in metal emissions into surface waters. One of the most important non-point sources is automobile traffic. Recent studies determining traffic related heavy metals in surface waters have concentrated mainly on worst case scenarios by analyzing heavy metal loads in waters and sediments close to storm-water overflow inlets. The present study aims at identifying traffic related heavy metals in moderately polluted sites, as they occur in highly urbanized regions. Therefore, the concentrations of eight traffic related metals (Pt, Sb, Mo, Cd, Pb, Cu, Cr and Zn) were determined in sediment and crustacean samples from eight different aquatic habitats in the Ruhr district, Germany. Traffic related heavy metals could be identified in sediment and biota samples as a combination of heavy metals (Pt, Sb, Cd, Pb for sediments and Pt and Sb for crustacean samples). Pt concentrations received special attention due to the relatively recent occurrence of anthropogenically emitted Pt in the environment. At six sampling sites, Pt was detected in sediment and/or biota samples. The uptake of Pt compared to other traffic related heavy metals by Asellus aquaticus and Gammarus pulex is relatively high and can be compared with the uptake rates of essential metals like Zn.

Animals↗

PubMed2005

The yeast ubiquitin ligase SCFMet30 regulates heavy metal response.

Cells have developed a variety of mechanisms to respond to heavy metal exposure. Here, we show that the yeast ubiquitin ligase SCF(Met30) plays a central role in the response to two of the most toxic environmental heavy metal contaminants, namely, cadmium and arsenic. SCF(Met30) inactivates the transcription factor Met4 by proteolysis-independent polyubiquitination. Exposure of yeast cells to heavy metals led to activation of Met4 as indicated by a complete loss of ubiquitinated Met4 species. The association of Met30 with Skp1 but not with its substrate Met4 was inhibited in cells treated with cadmium. Cadmium-activated Met4 induced glutathione biosynthesis as well as genes involved in sulfuramino acid synthesis. Met4 activation was important for the cellular response to cadmium because mutations in various components of the Met4-transcription complex were hypersensitive to cadmium. In addition, cell cycle analyses revealed that cadmium induced a delay in the transition from G(1) to S phase of the cell cycle and slow progression through S phase. Both cadmium and arsenic induced phosphorylation of the cell cycle checkpoint protein Rad53. Genetic analyses demonstrated a complex effect of cadmium on cell cycle regulation that might be important to safeguard cellular and genetic integrity when cells are exposed to heavy metals.

Adaptor Proteins, Signal Transducing↗

PubMed2003

An inventory of heavy metals inputs to agricultural soils in England and Wales.

An inventory of heavy metal inputs (Zn, Cu, Ni, Pb, Cd, Cr, As and Hg) to agricultural soils in England and Wales in 2000 is presented, accounting for major sources including atmospheric deposition, sewage sludge, livestock manures, inorganic fertilisers and lime, agrochemicals, irrigation water, industrial by-product 'wastes' and composts. Across the whole agricultural land area, atmospheric deposition was the main source of most metals, ranging from 25 to 85% of total inputs. Livestock manures and sewage sludge were also important sources, responsible for an estimated 37-40 and 8-17% of total Zn and Cu inputs, respectively. However, at the individual field scale sewage sludge, livestock manures and industrial wastes could be the major source of many metals where these materials are applied. This work will assist in developing strategies for reducing heavy metal inputs to agricultural land and effectively targeting policies to protect soils from long-term heavy metal accumulation.

Agriculture↗

PubMed2004

Heavy-metal pollution and its state in algae in Kakehashi river and Godani river at the foot of Ogoya mine, Ishikawa Prefecture.

Alga as Achnanthes minutissima among diatoms is a widely adaptable taxon on the state of an aquatic environment. In this study, it was found that diatom had a specific tolerance to heavy metals (Cu, Zn, Pb, and Cd etc.) in river water samples, because the diatom assemblage consisted of almost only Achnanthes minutissima in Kakehashi river and Godani river, which were polluted with waste water from Ogoya copper mine. The relationship between the concentrations of heavy metals (Cu, Zn, Pb and Cd) in river water and the attached substances (algae and silt etc.) and the relative abundances of diatom taxa were investigated in detail. The results indicated that the higher is the concentration of heavy metals in the river environment, the higher is only the relative abundances of Achnanthes minutissima. Thus, the taxon can be used as a bioindicator of heavy metal pollution. The relative rates of toxic chemical forms of copper in algae were 61 - 92% in the attached substances and 49-70% in the sediment on the river bed, respectively. Therefore, it was found that diatom as Achnanthes minutissima had a tolerance to heavy metals in river water, being able to live in such an environment. Since the water treated with calcium hydroxide from the deposition reservoir of Ogoya mine enters in Godani river, the river is polluted by heavy metals (Cu, Zn, Pb and Cd etc.). From the viewpoint of both biological and chemical analyses, Godani river is still polluted with heavy metals, because their concentrations in the river samples were very high. On the other hand, in Kakehashi river, the concentrations of heavy metals were very low and the distributions of some diatoms appeared in an unpolluted Nishimata river were observed. Therefore, Kakehashi river seems to be considerably recovered from heavy-metal pollution after closing the Ogoya mine.

Eukaryota↗

PubMed1998

Mobilization of heavy metals and arsenic in polluted wetland soils and its dependence on dissolved organic matter.

The wetland soils of the Mulde river in the industrial district of Bitterfeld-Wolfen (Germany) are highly contaminated with heavy metals and arsenic. We studied the mobility of accumulated heavy metals and arsenic and the influence of dissolved organic matter (DOM) on element mobility. Undisturbed soil cores were taken from five different sites to represent a wide range of heavy-metal contamination, soil properties and dissolved organic carbon (DOC) concentrations. The acid-soluble concentrations (mostly equal to the total content) were up to 1100 mg kg-1 for Zn, 800 mg kg-1 for Cr, 364 mg kg-1 for Cu, 265 mg kg-1 for As and 37 mg kg-1 for Hg, depending on the sampling site. Percolation experiments using small lysimeters with undisturbed topsoil cores illustrated a considerable mobilization of Zn, Cd, Cu, Cr and Hg, depending on soil properties. Up to 80 micrograms l-1 Cd, 8 mg 1-1 Zn, 130 micrograms l-1 Cr, 160 micrograms l-1 Cu and 7 micrograms l-1 Hg were detected in the soil percolates. Arsenic mobilization was low. The concentration of Cr, Hg, Cu and As in the soil percolates was positively correlated with DOM. Besides the element content (mobile or acid-soluble), soil pH and soil characteristics describing the soil potential for heavy-metal adsorption (clay, oxides, cation exchange capacity), the DOC concentration in the soil solution should be known to access the potential mobilization of Hg, Cr, Cu and As. In contrast, Cd and Zn mobilization depends on soil pH and mobile element content, but not on DOM. Additional studies on two soil profiles (down to 1.5 m) confirmed the translocation of heavy metals from the highly contaminated topsoil into deeper soil horizons and into the groundwater and the influence of DOM as revealed with the percolation experiment. Our results also showed that DOM is of minor importance on the mobilization of heavy metals in soils with a low soil pH (< 4.5).

Adsorption↗

PubMed2003

Release of heavy metals from Tunisian traditional earthenware.

Lead and other heavy metals are found to leach from the glazes of some Tunisian glazed earthenware in concentrations high enough to constitute a serious health hazard. When yellow/green and white/green colored mugs available on the Tunisian market were filled with acetic acid solutions, concentrations of up to 51 microg lead per ml of leachate were measured. The values greatly exceed the limit allowed by the US Food and Drug Administration (FDA) regulations for a 24-h leaching test. The use of a traditional milk derivative (leben) widely consumed as a beverage in Tunisia as a leaching agent shows that amounts as high as 1407 microg of lead is ingested per mug of milk derivative consumed. The use of such utensils may constitute a serious health hazard to the Tunisian consumer. Stringent regulations and controls are therefore required to protect the consumer against lead and other heavy metals of non-occupational origin.

Acetic Acid↗

PubMed2001

Heavy Metal Resistance of the Extreme Acidotolerant Filamentous Fungus Bispora sp.

To obtain information on the importance of membrane and zeta potentials as repelling or facilitating forces during the uptake of cationic trace elements, the heavy metal content and the growth resistance of the acidotolerant fungus Bispora. sp. to heavy metals were compared at pH 1.0 and pH 7.0. Cu, Co, Ni, Cd, Cr, and La contents of the fungus were significantly lower at pH 1.0 than at pH 7.0. A similar pH effect occurred with cationic macro elements such as Na, Mg, Ca, Fe, and Mn. Only K and Zn exhibited higher levels at pH 1.0 in the fungus than at pH 7.0. Macro and micro elements present in the medium in anionic form (sulfate, chloride) showed the opposite pattern to cations: Contents were higher at pH 1.0 than at pH 7.0. Minerals present at pH 1.0 predominantly in the electrical neutral, protonated form (phosphate, borate) exhibited a similar cell content at both acid and neutral pH (P) or a higher content at neutral pH than at acid pH (B). The resistance of fungal growth to the cations Cu, Zn, Ni, Co, Cr, and Cd was significantly higher at pH 1.0 than at pH 7.0. Such a difference was not observed with Hg, present in the medium at both pH values as electrically silent HgCl2. The anionic tungstate exhibited the opposite pattern to cationic heavy metals: The resistance of growth was higher at pH 7.0 than at pH 1.0. A greater growth resistance to heavy metals was correlated with a lower uptake of these elements, and vice versa; Uptake of heavy metals correlated with a lower resistance of fungal growth to these elements. The results are in agreement with the hypothesis that membrane and zeta potentials of the fungus are important factors controlling the uptake of heavy metals and thereby the resistance of growth to these elements: At pH 1.0 positive potentials of fungal hyphae impede the uptake of cationic heavy metals, but facilitate the uptake of anionic species. At neutral pH values the negative potentials facilitate the uptake of cations, but impede the uptake of anions.

Journal Article↗