SEARCH · PubMed Health

Results for “Metals, Heavy”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 757 records · Page 42Linked to original sources

PubMed1997

Isolation and characterization of heavy metals resistant bacteria from Lagos Lagoon.

A total of 228 bacteria with an ability to resist toxic heavy metals were isolated from 8 selected sites of the Lagos Lagoon. The bacteria isolated were Staphylococcus sp., Bacillus sp., Pseudomonas sp., Streptococcus sp., Moraxella sp., Escherichia coli, Proteus sp., Klebsiella sp. and Salmonella sp. The heavy metals to which resistance was recorded were mercury, lead, zinc, cobalt, copper and chromium. The lagoon sites from which the highest number of resistant bacteria were isolated were Marina and Ebute-Ero. The heavy metal to which most bacteria were resistant was cobalt, while the least was chromium. The significance of the result is discussed in relation to the Nigerian environment and human health.

Chlorides↗

PubMed1994

The heavy metal subculture and suicide.

The impact of the heavy metal music subculture on suicide has been the subject of much public debate but little scholarly research. The present paper assesses this relationship with data on heavy metal magazine subscriptions and youth suicide in the 50 states. We find that, controlling for other predictors of suicide, the greater the strength of the metal subculture, the higher the youth suicide rate. The music perhaps nurtures suicidal tendencies already present in the subculture. The model explains 51% of the variance in youth suicide.

Adolescent↗

PubMed2006

Ecotoxicological assessment of the impact of residual heavy metals on soil nematodes in the Guadiamar River Basin (Southern Spain).

On 25 April 1998, as a consequence of the breaking of a dam containing the tailings of a pyrite mine, a land strip of approximately 43 km in length was covered with a layer of black sludge, containing high levels of heavy metals, along the Guadiamar River Basin (southern Spain). In this investigation we carried out an ecotoxicological assessment (field and laboratory studies) of the impact of residual heavy metals (Cu, Pb, Zn, Ni) on soil nematodes in the impacted riparian zone, two years after the huge mine spillage. Concentrations of residual heavy metals were significantly (P<0.05) higher at the impacted sampling sectors (S-2, S-3, S-4, S-5) than at the unpolluted (reference) sampling sector (S-1). Nickel however exhibited the lowest increases at the impacted sectors. As a consequence, correlation coefficients between concentrations of heavy metals and values of ecological indices were not significant for Ni. In contrast, copper, lead and zinc exhibited significant (P<0.05) negative correlation coefficients with ecological indices, particularly with diversity indices (including the~number of taxa). In addition, the toxicity of Cu and Pb to nematode test species (Aphelenchus avenae and Cephalobus persegnis) during short-term toxicity bioassays was much higher than the toxicity of Zn and Ni. We conclude that residual heavy metals were still influencing adversely the community of soil nematodes in the impacted riparian zone of the Guadiamar River Basin. Cu, Pb and, to a lesser extent, Zn would be major responsible for the observed impact.

Animals↗

PubMed2001

Risk perception of heavy metal soil contamination and attitudes toward decontamination strategies.

Contaminated soils are a common environmental risk all over the world. One major source of risk is heavy metal soil contamination caused by industrial emissions. This quasiexperimental study investigated the perception of these risks by exposed and nonexposed people, their attitudes toward bioremediation methods using hyperaccumulating plants, and the influence of long-term aspects of sustainability on the acceptance of bioremediation methods. Major findings were that people living in a contaminated area perceived the risk of the heavy metal soil contamination as higher than the general risk of contamination. Second, a factor analysis showed that the factors dread, control, and catastrophic potential were relevant for the perception and valuation of low-dose environmental risks such as the contamination of the investigated area. In addition, a cluster analysis showed that the risk of heavy metal soil contamination was perceived as similar to that of oil contamination, ozone layer, preservatives and genetic technology. It was perceived indifferently with regard to dread. The uncontrollability of heavy metal soil contamination was estimated as medium, and its catastrophic potential as low. Third, exposed and nonexposed participants preferred bioremediation methods to classical methods (e.g., excavation and chemical treatment of the soil), because they perceived the environmental and esthetical performance of the bioremediation as important criteria. Sustainability or precautionary issues, such as the prevention of harm for future generations, were highly correlated with the acceptance of the use of bioremediation methods in people's residential areas.

Adult↗

PubMed2002

Determination of total petroleum hydrocarbons and heavy metals in soils within the vicinity of facilities handling refined petroleum products in Lagos metropolis.

This article discusses the determination of total petroleum hydrocarbons (TPH) and heavy-metal contamination in soils within areas of refined petroleum products handling in Lagos metropolis. Soil samples were collected randomly from two petrol stations, two auto-mechanic workshops, and a National Electric Power Authority (NEPA) station. Control samples were taken from two low-density residential areas. TPH were estimated gravimetrically following standard methods of TPH analysis, while the heavy metals were determined by atomic absorption spectrophotometry. Sites studied had higher levels of TPH and heavy metals compared to the control samples. For TPH, the petrol stations have mean values of 399.83+/-106.19 and 450.83 +/- 90.58 microg/g, respectively; mechanic workshops, 362.60 +/- 185.84 and 428.55 +/- 119.00 microg/g, respectively; while the NEPA station has 356.20 +/- 210.30 microg/g compared to the control mean of 26.63 +/- 4.58. It revealed that the improper handling of refined petroleum products are potential sources of soil contamination in the sampled sites. This is indicated by the statistically significant levels of TPH and heavy metals observed between the control samples and those collected from the petroleum products handling sites. Bioremediation using microorganisms and plants is recommended.

Chemical Industry↗

PubMed2001

"Electro-fishing" in the lab: a new method to detect acute effects of heavy metals and organic pollutants in invertebrate indicator organisms.

Acute toxicity of heavy metals and organic pollutants was examined using Rhabditis oxycerca (Nematoda) and Paramecium spec. (Protozoa, Ciliata) as indicator organisms. The substances tested were based on the composition found in the river Odra. They were used in graduated dilution series (1000-fold, 500-, 250-, 167-, 125-, 100-, and 83-fold of the Odra concentration). In a special apparatus with an electric field the animals were induced to migrate from the anode to the cathode. Their migration activity (distance) and the number of migrating animals were influenced by the substances tested. To assess the extent of damage, results were compared with controls (tap water) and reference substances (aldicarb and chloracetamide). The investigations showed that heavy metal concentrations > 100-fold of the Odra concentration led to behavioural changes of both test organisms. The organic pollutants, in contrast, did not cause detectable changes in ciliates and only led to slight reductions in the migration activity of nematodes, without concentration-dependent gradations.

Animals↗

PubMed2006

Isolation and identification of enterococci from seawater samples: assessment of their resistance to antibiotics and heavy metals.

A hundred Enterococcus strains were isolated from seawater samples collected from coastal areas of Istanbul. Isolates were identified to the species level using standard biochemical tests specified by Facklam and Collins. The species distribution was as follows Enterococcus faecalis (96%), Enterococcus gallinarum (3%) and Enterococcus solitarius (1%). The resistance of bacteria to both heavy metals (zinc [Zn], iron [Fe], cadmium [Cd], chrome [Cr], cobalt [Co]) and antibiotics (ampicillin 10 microg [AP], penicillin G 10 Units [PG], gentamycin 10 microg [GM], streptomycin 10 microg [S], chloramphenicol 10 microg [C], erythromycin 15 microg [E], kanamycin 30 microg [K], amikacin 30 microg [AK], nalidixic acid 30 microg [NA], and vancomycin 30 microg [VA]) was evaluated. None of the strains was resistant to VA. It was found that among the 100 isolates, those that exhibit resistance to antibiotics, particularly NA, S and K, were also resistant all the heavy metals tested. To our knowledge this is the first report focusing on determination of resistance of environmental enterococci found in Istanbul against heavy metals and antibiotics. Thus, combined expressions of antibiotic and heavy metal resistance may help to reinforce ecological and epidemiological studies and to determine the role of these strains in antibiotic and heavy metal resistance dissemination.

Anti-Bacterial Agents↗

PubMed2006

Evaluation of the in situ, time-integrated DGT technique by monitoring changes in heavy metal concentrations in estuarine waters.

Various natural and anthropogenic processes influence heavy metal concentrations within estuaries. In situ, time-integrated DGT measurements made over concurrent tidal phases found significantly higher concentrations of Cu (probability p=0.017), Zn (p=0.003) and Ni (p=0.003) during the flood phase, because the incoming tide passes several point sources. DGT-reactive Cu concentrations significantly decreased with increased tidal-flushing and vice versa within a marina (correlation r=-0.788, p=0.02). DGT measurements also recorded significant increases in Cu (4 out of 4 sites, p<0.001) and Zn (3 out of 4 sites, p< or =0.015) after a 24 mm rainfall event. Finally, DGT-reactive Cu increased significantly (p<0.001) during peak boating times, due to increased numbers of Cu-antifouled boats. This study demonstrates that, with judicious selection of deployment times, DGT measurements enable changes in heavy metal concentrations to be related to various cycles and events within estuaries.

Copper↗

PubMed1999

Concentration and mobilization of Cd, Cu, Pb and Zn by meiofauna populations living in harbour sediment: their role in the heavy metal flux from sediment to food web.

The bioavailability of Cd, Cu, Pb and Zn was assessed in different harbours of the Atlantic coast (France). The responses of the two dominant meiobenthic groups (nematodes and copepods) to a heavy metal contamination gradient measured in similar subtidal sediments were observed in field surveys. Heavy metal concentrations were measured in nematodes and copepods. Nematodes have higher Cd, Cu, Pb and Zn transfer factors than copepods or other benthic species. The flux of heavy metal through nematodes was estimated and appears to be important compared to plankton in the process of heavy metal transfer to benthic or pelagic food webs.

Animals↗

PubMed1999

Mobilization of heavy metals from Le An River sediment.

The release of sediment-bound heavy metals can have a significant influence on river water quality. Generally speaking, variations of pH and oxygen are among the most important chemical factors that affect the mobility of sediment-bound metals. Recent research has indicated that sulfide, measured as acid-volatile sulfide (AVS), is an important partitioning component of heavy metals. We determined the metal release potential of sediments from the Le An River which receives drainage from a major copper mining operation. We found that the in-situ Cu, Pb, Zn, Cd and As concentrations of the Le An River sediments below the mine are much higher than are the global background values, but that Ni was not elevated. There is potential for mobilization of bound metals to the overlying water, the order of metal release ratio in terms of pH dependencies is Zn > Cu > Cd approximately Pb. Sulfide is not a major binding component for metals in Le An River sediment. It is more likely that the iron and manganese oxides are the most important metal binding components in the sediments of the Le An River.

China↗

PubMed2006

A rapid fractionation method for heavy metals in soil by continuous-flow sequential extraction assisted by focused microwaves.

A microwave-assisted continuous-flow sequential extraction system was developed for rapid fractionation analysis of heavy metals in soil. Insertion of pressure-adjusted air between the extractants provided stable flows of the extractants without mutual mixing and back-pressure influence of a column packed with soil, thereby facilitating reliable continuous-flow extractions. In addition, use of pure water as a pumping solvent removed metal contamination because of direct contact between corrosive extractants and the pump containing metallic materials. Focused microwave irradiation to the soil accelerated the selective extractions of the acid-soluble and reducible fractions of heavy metals in soil in the first and second steps of the sequential extraction conditions, as defined by the Commission of the European Bureau of Reference (BCR). The microwave-assisted continuous-flow extraction provided high correlations in amounts of six heavy metals except Zn in the first step and Cu in the second step extracted from a reference sludge soil, BCR CRM 483, with a conventional batchwise extraction proposed by BCR; continuous-flow extraction assisted by conductive heating provided lower correlations for all the six metals. The proposed method drastically reduced the time required for the sequence extraction to ca. 65 min without losing accuracy and precision of the fractionation analysis of heavy metals in soil, whereas the BCR batchwise method requires ca. 33 h.

Chemical Fractionation↗

PubMed1977

Heavy metal pollution among autoworkers. II. Cadmium, chromium, copper, manganese, and nickel.

Garages and auto-repair workshops may be polluted with other heavy metals besides lead. Blood of autoworkers with high lead content was analysed for cadmium, chromium, copper manganese, nickel, ALAD activity and carboxyhaemoglobin level. Cadmium and copper levels in blood of autoworkers were comparable with those of the control subjects while chroimium and nickel levels were significantly higher (P less than 0-01 for both metals), and scattered raised values of manganese were found. There was no significant mutual correlation between levels of various heavy metals determined in whole blood. High copper levels were slightly related to decreasing ALAD activity (P less than 0-1). Nineteen per cent of autoworkers were found to have an abnormally blood level of carboxyhaemoglobin. The amount of particulate heavy metal in autoworkshop air was not related to biochemical abnormalities found in the autoworkers. Various sources of pollution of these heavy metals in autoworkshops are discussed.

Adolescent↗

PubMed2006

Axopodial degradation in the heliozoon Raphidiophrys contractilis: a novel bioassay system for detecting heavy metal toxicity in an aquatic environment.

We observed the physiological effects of zinc, lead, mercury, copper, cadmium, and arsenic on the axopodia of the centrohelid heliozoon Raphidiophrys contractilis. In the presence of these heavy metal ions, the axopodial length of the heliozoon decreased in a concentration-dependent manner. When the heavy metal ions were examined at the same concentration, mercury produced the strongest effect on axopodia. At a high concentration (> 10-3 M) of any of the heavy metal ions examined, axopodia disappeared and cells became disrupted. Axopodia were also degraded by the addition of solutions with an acidic (< or = 6) or basic (> or = 8) pH. These observations indicate the toxic effects of heavy metal ions and non-neutral pHs on axopodial length, and also signify that R. contractilis can be used as an effective biological tool for the study of metal poisoning in eukaryotic cells.

Animals↗

PubMed2006

Effects of Glomus mosseae on the toxicity of heavy metals to Vicia faba.

A glasshouse pot experiment was conducted to investigate effects of the arbuscular mycorrhizal fungus Glomus mosseae on the growth of Vicia faba and toxicity induced by heavy metals (HMs) (Cu, Zn, Pb and Cd) in a field soil contaminated by a mixture of these metals. There was also uninoculation treatment (NM) simultaneously. Mycorrhizal (GM) plants hav e significantlyincreased growth and tolerance to toxicity induced by heavy metals compared with NM plants. P uptake was significantly increased in GM plants. Mycorrhizal symbiosis reduced the transportation of HMs from root to shoot by immobilizing HMs in the mycorrhizal, shown by increasing the ratios of HMs from root to shoot. Oxidative stress, which can induce DNA damage, is an important mechanism of heavy metal toxicity. GM treatment decreased oxidative stress by intricating antioxidative systems such as peroxidases and non-enzymic systems including soluble protein. The DNA damage induced by heavy metals was detected using comet assay, which showed DNA damage in the plants was decreased by the GM treatment.

Comet Assay↗

PubMed2001

Heavy metal localisation in mycorrhizas of Epipactis atrorubens (Hoffm.) Besser (Orchidaceae) from zinc mine tailings.

The metal distribution within mycorrhizal and nonmycorrhizal roots of Epipactis atrorubens collected from zinc mine tailings and an area rich in heavy metal ores (both located in southern Poland) was investigated. The tailings, consisting of post-flotation material, were characterised by high levels of toxic elements such as Zn, Pb, and Cd, while soil outside the tailings was also strongly enriched in heavy metals. Atomic absorption spectrometry and proton-induced X-ray emission analysis revealed that heavy metals were mostly accumulated within orchid roots. Elemental maps from proton-induced X-ray emission showed that plant root epidermis and fungal coils which had developed within cortical cells of roots collected from the zinc mine tailings were the main places of Zn and Pb accumulation, associated with increased concentrations of Fe, Cd, Ti, Mn, Si, Ca, and S. The mean content of Pb and Zn in the coils was 4 to 5 times higher than in the root epidermis. In mycorrhizal roots from the tailings a statistically significant decrease in Pb and Zn content towards the inside of the root was observed. The mean content of Pb in coils from roots of plants growing outside the tailings was about 1% of the concentration in root coils from the tailings. Coils selected from orchid roots originating from a site outside the tailings contained comparatively high concentrations of Zn, Cd, and Cu, which was probably due to the high content of these elements in the soil. The results presented suggest a biofiltering effect against heavy metals by orchid mycorrhizal fungi.

Industrial Waste↗

PubMed2005

Heavy metal concentrations in human eyes.

PURPOSE: To measure the concentration of toxic heavy metals in the fluids and tissues of human eyes. DESIGN: Laboratory investigation. METHODS: Thirty autopsy eyes of 16 subjects were dissected to obtain the aqueous, vitreous, lens, ciliary body, retina, and retinal pigment epithelium/choroid. Concentrations of lead, cadmium, mercury, and thallium in ocular tissues, ocular fluids, and blood were determined using an inductively coupled plasma-mass spectrometer and expressed as ng/g. Heavy metal concentrations in ocular tissues were compared using a paired t test. RESULTS: Lead and cadmium were found in all of the pigmented ocular tissues studied, concentrating to the greatest extent in the retinal pigment epithelium/choroid (mean, 432 +/- 485 ng/g and 2,358 +/- 1,522 ng/g). Cadmium was found in the retina in all eyes (mean, 1,072 +/- 489 ng/g) whereas lead was found in the retina in 9 (30%) of 30 eyes (mean, 53 +/- 54 ng/g). Trace concentrations of lead and cadmium were detected in the vitreous (mean, 0.5 +/- 1.0 ng/dl and 19 +/- 29 ng/dl), lens (mean, 13 +/- 18 ng/g and 20 +/- 18 ng/g), and blood (mean, 0.5 +/- 1.2 mug/dl and 3.1 +/- 4.1 mug/l) but were not detected in the aqueous. Mercury and thallium were not detected in any ocular tissues or fluids or in the blood. CONCLUSIONS: Lead and cadmium accumulate in human ocular tissues, particularly in the retinal pigment epithelium and choroid. The potential ocular toxicity of these heavy metals and their possible role in eye disease requires further study.

Aged↗

PubMed1998

Heavy metals inhibit limb regeneration in horseshoe crab larvae

We studied the effects of heavy metals on the regeneration of walking legs in horseshoe crabs (Limulus polyphemus). The second walking leg was amputated in embryos (stage 20 and 21) and first instar (trilobite) larvae, and the length and morphology of the regenerated appendage was observed after molting to the second instar stage. Regeneration following continuous exposure to TBT (0. 001-100 mg/L), mercury (0.001-100 mg/L), cadmium (0.01-100 mg/L), chromium (0.1-100 mg/L), lead (0.1-100 mg/L), and copper (1-100 mg/L) was measured relative to regeneration in seawater. Although regeneration was incomplete in controls, treatment with heavy metals led to smaller and/or malformed legs. The impacts of heavy metals on survival, molting, and regeneration of horseshoe crab larvae were ranked as follows: organotin > Hg > Cd > Cr > Zn > Pb >== Cu. Cu and Pb did not inhibit regeneration, even at 100 mg/L. TBT, Hg, Cd, Cr, and Zn inhibited the regeneration of appendages, although first instar larvae successfully molted into second instars even after treatment. Regeneration was comparable to seawater controls in less than 2.5 mg/L Zn. In 5.0 and 10.0 mg/L Zn, regeneration was inhibited and the length of regenerated appendages remained shorter in all second instars. Larvae treated with 10 mg/L Zn for 1-week intervals during the molt cycle showed similar patterns of regeneration. The regeneration of claws was not all or none, and formation of the claw was proportional to the length of regenerated appendages. Limb regeneration in horseshoe crab larvae may be a useful model system for the study of pollutant impacts.

Journal Article↗

PubMed2000

Engineering bacterial biopolymers for the biosorption of heavy metals; new products and novel formulations.

Bioremediation of heavy metal pollution remains a major challenge in environmental biotechnology. One of the approaches considered for application involves biosorption either to biomass or to isolated biopolymers. Many bacterial polysaccharides have been shown to bind heavy metals with varying degrees of specificity and affinity. While various approaches have been adopted to generate polysaccharide variants altered in both structure and activity, metal biosorption has not been examined. Polymer engineering has included structural modification through the introduction of heterologous genes of the biosynthetic pathway into specific mutants, leading either to alterations in polysaccharide backbone or side chains, or to sugar modification. In addition, novel formulations can be designed which enlarge the family of available bacterial biopolymers for metal-binding and subsequent recovery. An example discussed here is the use of amphipathic bioemulsifiers such as emulsan, produced by the oil-degrading Acinetobacter lwoffii RAG-1, that forms stable, concentrated (70%), oil-in-water emulsions (emulsanosols). In this system metal ions bind primarily at the oil/ water interface, enabling their recovery and concentration from relatively dilute solutions. In addition to the genetic modifications described above, a new approach to the generation of amphipathic bioemulsifying formulations is based on the interaction of native or recombinant esterase and its derivatives with emulsan and other water-soluble biopolymers. Cation-binding emulsions are generated from a variety of hydrophobic substrates. The features of these and other systems will be discussed, together with a brief consideration of possible applications.

Bacteria↗