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PubMed2005

Trace metals, stable isotope ratios, and trophic relations in seabirds from the North Pacific Ocean.

Trace elements including mercury, cadmium, selenium, and stable nitrogen isotope ratios (sigma15N) were measured in tissues of Pacific seabirds. Two species of albatross (Diomedea immutabilis, Diomedea nigripes), four species of shearwaters (Puffinus bulleri, Puffinus carneipes, Puffinus griseus, Puffinus tenuirostris), northern fulmar (Fulmarus glacialis), and horned puffin (Fratercula corniculata) were collected opportunistically by an experimental fishery in the North Pacific Ocean. Two species each of petrels (Oceanodroma leucorhoa, Oceanodroma furcata) and auklets (Ptychoramphus aleuticus, Cerorhinca monocerata) were collected at breeding colonies on the north coast of British Columbia, Canada. Concentrations of toxic trace metals varied considerably among the pelagic nonbreeders; highest concentrations consistently were in D. nigripes (e.g., Hg), 70-fold greater than F. corniculata (e.g., Cd), eightfold greater than P. tenuirostris (e.g., Se), and fourfold greater than F. corniculata. Most essential trace elements varied little among species, consistent with physiological regulation. Values for sigma15N correlated positively with hepatic Se (r = 0.771, p = 0.025) and negatively with Co (r = 0.817, p = 0.013). Among the four breeding species, there were significant positive associations for sigma15N in muscle and hepatic Se (r = 0.822, p = 0.002), Hg (r = 0.744, p = 0.0001), and Cd (r = 0.589, p = 0.003). Differences in time scales integrated by sigma15N versus trace metals in tissues probably reduced the apparent associations between trace-metal exposure and diet.

Animals↗

PubMed2002

A dynamic leaching method for the assessment of trace metals released from hydraulic binders.

With respect to sustainable development, the leachability of trace metal from solid materials in contact with water has focused much attention over the years. Portland cements produced in industrial kilns generally contain from 10 to 300 mg/kg of trace metals. The behaviour of these endogenous metals has been, in this regard, the target of different leaching studies. Many of these researches concluded that heavy metals release are lower than analytical detection limits. Although satisfying from an environmental point of view, it induces a lack in the knowledge about the trace metals behavior during the leaching of cement based material. Accordingly, we designed the CTG-LEACHCRETE device, a dynamic leaching system (modified Soxhlet type) that overcomes this difficulty and allows long term monitoring. The experimental procedure is presented and preliminary results are discussed.

Manufactured Materials↗

PubMed1992

[Investigation of the profile of selected trace metals in genetically obese (ob/ob) and lean (+/?) mice].

Trace metals are known to have important effects on the activity of metalloenzymes and insulin secretion and to be involved in the etiology of various diseases. This study was designed to investigate the distribution and concentration of selected trace metals in the tissues of genetically obese mice, which were known to have hyperinsulinemia. Different phenotypes (ob/ob; +/?) and sexes of 4, 8, 12 week-old mice were killed by decapitation. Metal levels (Zn, Cu, Cd, Cr) in the brain, liver, serum, hair and carcass were determined by an atomic absorption spectrometer. The results showed that obese mice had lower concentrations of zinc in the serum, hair, liver and carcass than lean controls (p less than 0.05), but there was no difference in the brain. Obese mice also had a low carcass cadmium concentration (p less than 0.01), which depended on the sex-age interaction. When expressed in terms of total content, obese mice had higher total liver zinc and carcass chromium contents (p less than 0.05). Obese mice had a higher total carcass copper content at 8 weeks of age. Serum and carcass zinc were showed to be inversely related to body fat in obese mice. The results indicate that zinc may play a special role in thermoregulation and fat metabolism in the liver of obese mice. The tissue distribution and absorption of zinc may have an important correlation in the development of obesity. The roles of copper, cadmium and chromium are still obscure, the related regulations are still open for further questions.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMedDate not supplied

Electrothermal atomic absorption spectrometry of trace metals in biological fluids.

Electrothermal atomic absorption spectrometry has five major advantages for measurements of trace metals in biological materials, in comparison to measurements by conventional flame atomic absorption analysis: (1) Trace metal contamination is minimized by avoidance of preliminary chemical extractions and additions of reagents; (2) Sample volumes are small (1 to 50 mu1). The entire sample is vaporized in electrothermal atomization, whereas in most flame nebulization systems only a small fraction of the sample enters the flame; (3) Atoms are released in higher concentrations. In electrothermal atomization, the atom cloud is released into a relatively small volume of gas. In contrast, in flame atomization, the atom cloud is diluted by the high flow rate of gases and by expansion of gases during combustion; (4) Molecular recombination of atoms is retarded by the atmosphere of inert gas which restricts chemical reactions (e.g., oxidation). In contrast, in flame atomization, oxidation occurs very rapidly; and (5) By programmed increments in temperature, electrothermal atomization permits organic constituents to be pyrolyzed prior to vaporization and atomization of metals. Despite these advantages, electrothermal atomic absorption is particularly subject to interferences and sources of imprecision which necessitate critical evaluations in the prospective analyst's laboratory before an electrothermal method can be confidently employed for diagnostic measurements of a specific trace metal in body fluids.

Body Fluids↗

PubMedDate not supplied

Selenium supplementation in low-birthweight premature infants: relationship to trace metals and antioxidant enzymes.

We attempted to study the effect of selenium supplementation upon trace metal metabolism in low-birthweight infants less than 1000 g birthweight. Serum levels of the trace metals copper, zinc, and selenium; and white blood cell glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) activities were measured in conjunction with the trace metals when parenteral nutrition (TPN) was begun (sample A), at the initiation of enteral nutrition (sample B), and when TPN was discontinued (sample C). Two randomly selected groups of infants were evaluated: group S received selenium supplementation (1.34 micrograms/kg per d) in their parenteral nutrition solutions; group C was a control which did not receive selenium supplementation. Selenium levels declined to equally low levels in both groups by sample C, but were significantly higher in group S at sample B. GSH-Px activities demonstrated a significant increase at sample B in group S and then tended to decrease. In group C, GSH-Px tended to increase, then decreased significantly by sample C. Both groups received 20 micrograms/kg per d of copper in TPN, however, serum copper declined significantly at sample B in group S whereas there were no significant changes in group C. There were no significant changes in zinc and SOD levels. There were no significant differences between groups in clinical characteristics or outcome. This study suggests that a dose of supplemental selenium of 1.34 micrograms/kg per d in TPN is inadequate for low-birthweight premature infants. Selenium supplementation may also affect copper metabolism.

Copper↗

PubMed2003

The distribution of trace metals in Florida Bay sediments.

The distribution of trace metals based on surface sediments collected at 40 stations across Florida Bay was done in June, November and February 2000-2001. Concentrations of Sc, V, Ba, Cd, Cr, Co, Cu, Pb, Mn, Ni, Zn, Al and Mg were determined by ICP-MS, and the total Fe was determined by spectrophotometry. Organic carbon (OC), nitrogen (N), and calcium carbonate (CaCO3) were also measured. Eleven of 13 metals showed a similar distribution pattern for the various months studied. Maximum concentrations of metals were lower than those found in most estuarine systems and were concentrated in the north-central and western zones of the Bay. The Mn and Fe concentrations, unlike the other metals, gradually decreased from north (Everglades) to south (Florida Keys). Some metals (Ni, Zn, Cu, Cr, Pb and Ba) associated with petroleum use showed high concentrations at stations near the Tavernier marina. Florida Bay sediments are predominately CaCO3 (65.9-92.5%). The greatest value for OC (5.5%) and the lowest value of CaCO3 (65.9%) were found in the western zone. Trace metal distribution patterns are similar to the OC and N in the sediments. There was a strong correlation between most metals (V>Cu>Ni>Cr>Al>Co>Ba>Zn>Pb>Mg) and the percentage of OC. The maximum C/N values (9-12) were observed at the stations with the highest OC, where dense colonies of seagrass are found and most of the metals are concentrated. All metals except Mg, Mn and Co showed a strong correlation with Al and the fine fraction of the sediments (aluminosilicates) associated with continental input and river runoff.

Calcium Carbonate↗

PubMed2002

Waste ashes for use in agricultural production: II. Contents of minor and trace metals.

The present study was carried out to examine the contents of 18 minor and trace metals in five typical municipal waste ashes in Japan. In the waste ashes, Li, Ga, Rb, Y, Zr had relatively higher concentrations, approximately 5-300 mg kg(-1), the remaining metal concentrations were generally approximately 0.05-20 mg kg(-1). A comparison of the metal concentrations in the waste ashes and in Japanese agricultural soils indicated that the ratios for Ga, Mo, Ag, Sb, W, Bi between sewage sludge ash (SSA) and the soils were approximately 10-100 and for the remaining metals approximately 0.2-2; the ratios between food scrap ash (FSA), animal waste ash (AWA), horticulture waste ash (HWA) and incinerator bottom ash (IBA) and the soils were approximately 0.2-5. Furthermore, an overall evaluation on the waste ashes was also carried out using factor analysis with the addition of the other 21 elements examined in a companion paper. In the waste ashes, the major nutrient elements and heavy metals were mainly described by four factors: factors 1 and 2 explained the main information of the minor and trace metals while factors 3 and 4 explained that of the major nutrient elements. Factor 2 in the score plots could be used to evaluate the potential risk of the waste ashes to agricultural soils. Of the five types of waste ashes, SSA and IBA were abundant with minor and trace metals; AWA was relatively abundant with major nutrient elements especially for K; FSA was relatively abundant with major nutrient elements except for K, while HWA was not abundant with either of them.

Agriculture↗

PubMed1980

Myocardial cations and trace metals in cardioplegia: a clinical study.

Cations and trace metals play important roles in the pathophysiology of myocardium, and understanding their changes during cardioplegia may be important in further refining the technique of myocardial protection. Serial myocardial, blood and urine samples were taken from 12 patients undergoing cardiac operation under cold cardioplegia. The concentrations of calcium, magnesium, zinc and copper were measured with an atomic absorption spectrometer. Myocardial magnesium levels were found to be significantly (P less than 0.05) depleted when the "cardioplegic" solution contained 0.69 mmol/l of magnesium, but this could be prevented by increasing the magnesium concentration of the infusate to 2.2 mmol/l. With calcium-free infusate, the myocardial calcium concentration decreased, but zinc and copper values did not change significantly. There were decreased serum concentrations of these cations and trace metals during tbe hemodilution cardiopulmonary bypass but their 24-hour excretions in urine were within normal range. Although the clinical importance of such changes remains to be elucidated, the information may be valuable in designing future cardioplegic solutions with optimal compositions.

Calcium↗

PubMed2004

A study of Nafion-coated bismuth-film electrodes for the determination of trace metals by anodic stripping voltammetry.

This work reports on the fabrication, characterization and applications of Nafion-coated bismuth-film electrodes (NCBFE's) for the determination of trace metals by anodic stripping voltammetry (ASV). A NCBFE was typically prepared by first applying a 5 microl drop of a 1% Nafion solution onto the surface of a glassy-carbon rotating-disk electrode. After evaporation of the solvent, the Bi film was plated on the electrode in situ(i.e. by spiking the sample with 1000 microg l(-1) of Bi(iii) and simultaneous electrolytic deposition of the metal ions and bismuth film on the electrode surface at -1.4 V) or ex-situ(i.e. by electrolytic deposition of the bismuth film in a separate solution containing 1000 microg l(-1) of Bi(iii), followed by the ASV measurement step in the sample solution). Various fabrication and operational parameters were thoroughly investigated and discussed in terms of their effect on the ASV signals. It was found that this voltammetric sensor was suitable for the determination of metals at trace levels by square-wave ASV (SWASV) due to its multi-element detection potential, improved analytical sensitivity, high resistance to surfactants, low cost, ease of fabrication, robustness, speed of analysis and low toxicity (as compared to traditional mercury electrodes). In the presence of 4 mg l(-1) of Triton X-100, the NCBFE afforded a 10-fold peak height enhancement for the Pb peak and a 14-fold enhancement for the Cd peak over a bare BFE while the determination of Zn was feasible only on the NCBFE. The limits of detection (at a signal-to-noise ratio of 3) were 0.1 microg l(-1) for Cd and Pb and 0.4 microg l(-1) for Zn for a deposition time of 10 min. Finally, the electrode was applied to different real samples (tap-water, urine and wine) for the analysis of trace metals with satisfactory results.

Bismuth↗

PubMed1977

The role of trace metals in calcium urolithiasis.

Ten urinary stones composed of calcium oxalate or a mixture of calcium oxalate and calcium phosphate were analyzed for trace metal content by emission spectroscopy. Trace metals found in amounts of 0.001 per cent or more were iron, copper, zinic, tin, lead, and aluminum. The inhibitory effect of each of these trace metals on the crystal growth of calcium oxalate and calcium phosphate was tested. Results indicated that none of the metal affect the crystal growth of calcium oxalate at concentrations approximating those found in normal urine. The metal ions copper (II), zinc (II), tin (II), and aluminum (III) did affect the crystal growth of calcium phosphate when present at physiologic concentrations; however, their contribution to the total calcium phosphate inhibitor activity in urine was estimated to be insufficient to have a regulatory role in urinary stone growth.

Aluminum↗

PubMed1998

Twenty years of trace metal analyses of marine mammals in Alaska: evaluation and summation.

The compilation of existing data on contaminants in the marine food chain is essential in addressing concerns regarding the magnitude of potential human exposures and in the evaluation of subsistence food safety. This paper presents a summary of studies on trace metals in tissues of Alaska marine mammals from the 1970s to the present, along with derived mean tissue trace metal concentrations. The derived mean can serve as a norm against which future monitoring results may be compared, and may be used to estimate human exposure to trace metals through the consumption of marine mammals. Additionally, the variation among studies in the reported mean tissue concentrations has been described through a derived standard deviation. Sufficient analytical and methodological details were available to derive means and standard deviations for tissues in bearded seal, bowhead whale, beluga whale, fur seal, harbor seal, Pacific walrus, and ringed seal. A high concordance between trace metal values reported in tissues (i.e., liver, kidney, muscle) was observed despite significant differences in reported sampling and analytical methodologies. Consistent with other reviews of trace metal concentrations in marine species, the standard deviation of tissue metal concentrations was generally < or = 100% of the reported mean. Significant gaps in available information remain, particularly for muscle tissues and for methylmercury, despite the considerable efforts to monitor marine mammal species in Alaska.

Alaska↗

PubMedDate not supplied

Distribution and movement of sludge-derived trace metals in selected Nigerian soils.

Use of metal-rich sewage sludge as soil fertilizer may result in trace- metal contamination of soils. This study was conducted to evaluate the effects of long-term sludge application on trace-metal (Zn, Cu, Pb, and Ni) distribution and potential bioavailability in Nigerian soils under a tropical wet-dry climate. Total metal analyses, sequential chemical fractionation, and DTPA extractions were carried out on samples of control and sludge-amended pedons in Nigeria (a Rhodic Kandiustult and two Rhodic Kandiustalfs from Nigeria, respectively). The sewage sludge applied to the soils contained higher levels of Zn and Cu than Pb and Ni. The control pedon contained low levels of all four metals. Soil enrichment factors (EF) were calculated for each metal in the sludge-amended pedons. Compared with the control soil, the sludge-amended pedons showed elevated levels of Zn and Cu, reflecting the trace-metal composition of the sewage sludge. Zinc and Cu in the sludge-amended soils were strongly enriched at all depths in the profile, indicating that they had moved below the zone of sludge application. The sequential extraction and DTPA analyses indicated that the sludge-amended soils contained more readily extractable and bioavailable metal ions than the unamended soil.

Agriculture↗

PubMedDate not supplied

Trace metal leaching through a soil-grassland system after sewage sludge application.

To determine whether sludge applications to soil would lead in the short term to toxicity to plants and trace metal leaching to ground water, we studied the fate of some trace and major elements in a brown soil-meadow system just after repeated sewage sludge applications. The main pathways were quantified over a 37-mo period with undisturbed monolith lysimeters including two controls, four lysimeters treated with 3 x 100 m3 ha-1, and four with 3 x 400 m3 ha-1 of sewage sludge. In drainage waters the effect was limited in time and, in the case of NO3-N and Cl, delayed by 1 to 4 mo and lasted several months before returning to background conditions. Nickel and Cu concentrations in solution increased also after sludge application and had not return to background conditions after 20 mo. Trace metal concentrations did not reach toxic levels in herbage and N, Cu, Cd, and Zn concentrations were correlated with the first sludge input only. Calculated over a 37-mo period, total element output was significantly increased for Ca, NO3-N, and Ni only, because of the time-dependent response to sludge application and high variability between replicates. Output was maximal for Cd, with 1.5% of total input for the 100 m3 ha-1 treatment. Particulate matter in drainage water accounted for an average of 20% of trace metal leaching. The main long-term risk was the rapid increase in trace metal concentrations in the topsoil, which may eventually lead to toxic levels in herbage.

Conservation of Natural Resources↗

PubMed2006

Bioavailability of trace metals to aquatic microorganisms: importance of chemical, biological and physical processes on biouptake.

An important challenge in environmental biogeochemistry is the determination of the bioavailability of toxic and essential trace compounds in natural media. For trace metals, it is now clear that chemical speciation must be taken into account when predicting bioavailability. Over the past 20 years, equilibrium models (free ion activity model (FIAM), biotic ligand model (BLM)) have been increasingly developed to describe metal bioavailability in environmental systems, despite the fact that environmental systems are always dynamic and rarely at equilibrium. In these simple (relatively successful) models, any reduction in the available, reactive species of the metal due to competition, complexation or other reactions will reduce metal bioaccumulation and thus biological effects. Recently, it has become clear that biological, physical and chemical reactions occurring in the immediate proximity of the biological surface also play an important role in controlling trace metal bioavailability through shifts in the limiting biouptake fluxes. Indeed, for microorganisms, examples of biological (transport across membrane), chemical (dissociation kinetics of metal complexes) and physical (diffusion) limitation can be demonstrated. Furthermore, the organism can employ a number of biological internalization strategies to get around limitations that are imposed on it by the physicochemistry of the medium. The use of a single transport site by several metals or the use of several transport sites by a single metal further complicates the prediction of uptake or effects using the simple chemical models. Finally, once inside the microorganism the cell is able to employ a large number of strategies including complexation, compartmentalization, efflux or the production of extracellular ligands to minimize or optimize the reactivity of the metal. The prediction of trace metal bioavailability will thus require multidisciplinary advances in our understanding of the reactions occurring at and near the biological interface. By taking into account medium constraints and biological adaptability, future bioavailability modeling will certainly become more robust.

Bacteria↗

PubMed1998

Differential cytotoxicity of trace metals in cisplatin-sensitive and -resistant human ovarian cancer cells.

Cellular resistance of cisplatin is related to various factors such as membrane transformations, changes in cellular transport systems, and an increased efflux of cisplatin by the tumor cells. Deficiencies of one or more trace metals can affect normal physiological functions, leading to altered enzymatic activities and a reduction in immune responses. This in vitro investigation was undertaken to study and determine the differential cytotoxicity of certain trace metals in human ovarian cancer cells that were sensitive and resistant to cisplatin. Standard cytotoxicity assays were performed using the neutral red assay. In general, the cisplatin-resistant cells exhibited an increased resistance to the externally supplied trace metals. For both cell lines the rank order of cytotoxicity from greatest to least with the non-essential metals was Cd2+ > Bi3+, and for the macrometals, Ca2+ > K+ > Mg2+. The transition metals and selenium exhibited a slight difference between the two cell lines with respect to the order of cytotoxicity. The cisplatin-sensitive cells had a rank order of V5+ > Se6+ > Cu2+ > Zn2+ > Fe3+, from greatest to least toxicity. The cisplatin-resistant cells had a rank order of Cu2+ > V5+ > Se6+ > Zn2+ > Fe3+. Since trace metals have various functions in maintaining normal health, these results provide key baseline cytotoxicity data and show that, in general, cytotoxic resistance to the trace metals tested followed a pattern similar to cellular cisplatin resistance.

Antineoplastic Agents↗

PubMed2005

Feeding ecology of five commercial shark species of the Celtic Sea through stable isotope and trace metal analysis.

In order to trace their feeding habits, stable carbon and nitrogen isotope ratios (delta15N and delta13C), as well as trace metal concentrations (Zn, Cd, Fe, Cu, Se and Hg) were analysed in the tissues of five commercial shark species from the Celtic Sea: the tope shark Galeorhinus galeus, the black-mouthed catshark Galeus melastomus, the starry smooth hound Mustelus asterias, the spiny dogfish Squalus acanthias and the lesser-spotted dogfish Scyliorhinus canicula. Our results were compared to previously described stomach contents and isotopic composition of potential preys. Isotopic ratio delta15N suggested that tope sharks fed at a higher trophic level (16.7 per thousand in the muscle) than the other species, reflecting its piscivorous diet. The lower values of spiny dogfish (11.6 per thousand in the muscle) might be explained, amongst other things, by either its migratory behaviour or its preference for preys from lower trophic levels. Cd and Hg were correlated with isotopic ratios delta13C and delta15N, and were shown to be diet-related whereas Zn, Fe and Cu seemed much more linked to species-specific metabolism. Although this multidisciplinary approach is revealed as a useful tool for the study of shark ecology, the lack of known trophic fractionation suggests that isotopic data be compared to traditional diet analyses.

Animals↗

PubMed2004

Historical trace metal fluxes in the Mexico City Metropolitan Zone as evidenced by a sedimentary record from the Espejo de los Lirios lake.

The accumulation of selected trace metals (Ag, Cd, Co, Cr, Cu, Hg, Ni, Pb, V and Zn) was studied in a sediment core collected at Espejo de los Lirios lake, a precipitation-dominated seepage lake in Northern Mexico City Metropolitan Zone (MCMZ). A (210)Pb-derived chronology, obtained from the same core, was used to reconstruct the historical metal fluxes at the site, allowing evaluation of the impact of environmental changes promoted by the development of the City during the last approximately 125 years. The highest levels of metal enrichment above natural concentration levels (NCL) in the sediments from Espejo de los Lirios lake were found for Ag and Pb (approximately 250%) as well as a slight enrichment for Cd (55%), Cr (84%), Co (20%), Cu (60%), Hg (47%), Ni (45%), V (59%) and Zn (66%). Fluxes of trace metals appeared to have noticeably increased from the last 45 years showing the maximum increments for Cd, Co, Cr, Ni, V and Zn during the 1980's (9 to 13 fold natural fluxes), for Ag and Cu (17 and 12 fold, respectively) during the 1990's and for Hg and Pb (2 and 13 fold) during the middle 1970's. Low levels of metal enrichment observed have evidenced that the most conspicuous consequences of the expansive growth of this area of the MCMZ, are mostly related to deforestation and erosion of the surrounding areas, rather than to trace metal pollution. Based on PCA, it can be assumed that atmospheric deposition, weathering of bedrock and soil within the watershed and authigenic production, are the most important processes that explain the trace metal distribution in the site.

Calcium Carbonate↗

PubMed2004

Effect of trace metal availability on coccolithophorid calcification.

The deposition of atmospheric dust into the ocean has varied considerably over geological time. Because some of the trace metals contained in dust are essential plant nutrients which can limit phytoplankton growth in parts of the ocean, it has been suggested that variations in dust supply to the surface ocean might influence primary production. Whereas the role of trace metal availability in photosynthetic carbon fixation has received considerable attention, its effect on biogenic calcification is virtually unknown. The production of both particulate organic carbon and calcium carbonate (CaCO3) drives the ocean's biological carbon pump. The ratio of particulate organic carbon to CaCO3 export, the so-called rain ratio, is one of the factors determining CO2 sequestration in the deep ocean. Here we investigate the influence of the essential trace metals iron and zinc on the prominent CaCO3-producing microalga Emiliania huxleyi. We show that whereas at low iron concentrations growth and calcification are equally reduced, low zinc concentrations result in a de-coupling of the two processes. Despite the reduced growth rate of zinc-limited cells, CaCO3 production rates per cell remain unaffected, thus leading to highly calcified cells. These results suggest that changes in dust deposition can affect biogenic calcification in oceanic regions characterized by trace metal limitation, with possible consequences for CO2 partitioning between the atmosphere and the ocean.

Atmosphere↗