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At least 109 records · Page 6Linked to original sources
PubMed1988

The asiatic clam, Corbicula fluminea: An indicator of trace metal pollution in the Shatt al-Arab River, Iraq.

The potential of Corbicula fluminea (Müller) as an indicator for trace metal pollution was investigated. Laboratory experiments show that Corbicula has the capability to accumulate and eliminate trace metals in relation to their concentrations in ambient water. However, an effect of individual size was observed. Seasonal variations in the concentrations of Cd, Co, Cu, Fe, Mn, Ni, Pb, V and Zn in Corbicula, water and particulate matter from the upper section of the Shatt al-Arab River were studied. Sediment samples were also analysed. Metal concentrations were determined by means of flameless AAS. It was found that Corbicula is a suitable bio-indicator for monitoring of trace metal pollution. Metal concentrations in Corbicula tissues correlated better with their corresponding concentrations in particulate matter than with the dissolved form. Temporal variations in metal concentrations were attributed to several factors, including fluctuations in metal inputs, and in geochemical and hydrological characteristics of the water. The obtained levels of trace metals were comparable to those reported for control sites, with the exception of Cd, Cu and Zn whose concentrations were higher in both Corbicula and particulate matter.

Journal Article↗
PubMed1983

Compartmental models for trace metals in mammals.

Kinetic models for the distribution and elimination of certain trace metals in mammals allow evaluation of metal burdens in critical target organs under time-variables exposure patterns, and thus may assist in formulating exposure standards. The linear compartmental model is described and some of its implications for conceptual models of trace metal metabolism are developed. The model is then applied to data on multiple doses of cadmium in mice. Many trace metals do not follow simple linear kinetic models because exposure to more than one metal simultaneously often results in synergistic effects.

Animals↗
PubMed1999

Turritella attenuata (Kasinathan): as biological indicator of marine pollution--a trace metal analytical study.

A study to monitor marine pollution with reference to trace elements (Fe, Zn, Mn and Cu) on T. attenuata, commonly called as screw shell over a period of one year on the whole body and various organs, viz. digestive diverticula, foot, mantle and ovary was conducted from the sandy beach of Porto Novo Coast (Lat 11 degrees 29' N Long: 79 degrees 46' E) of Peninsular India using Atomic Absorption Spectrophotometer (AAS). Higher concentration of all the four trace metals analysed were recorded in the digestive diverticula, whereas lower concentration of zinc and manganese were recorded in the ovary during the monsoon period. The higher level of trace metal concentration in the monsoon period may be due to the presence of these pollutants in large amounts in water. The accumulation of selected trace metals varies in different seasons according to the extent of pollution load in the marine environment.

Animals↗
PubMed2003

Trace metal distribution and control in the pilot-scale bubbling fluidized bed combustor equipped with the pulse-jet fabric filter, limestone injection, and the humidification reactor.

This work focused on trace metal behavior and removal in a fabric filter or in a humidification reactor during the cofiring of sawdust and refuse-derived fuels (RDFs) in a pilot-scale bubbling fluidized bed (BFB) boiler. Trace metal emissions measurements before and after the fabric filter revealed that removal efficiency in the fabric filter was in the range of 80-100%, and that the European Union (EU) Directive on Incineration of Waste restrictions for trace metal emissions are easily achieved even if addition of RDFs substantially increases the concentration of trace metals in fuel blends. Limestone injection enhanced the removal of As and Se but had no noticeable effect on the removal of other trace metals. Extensive formation of HgCl2 and condensation on fly ash particles during sawdust plus 40% RDF cofiring resulted in a 92% Hg removal efficiency in the fabric filter. Limestone injection had no effect on the Hg removal in the fabric filter but decreased the Hg removal in a humidification reactor from 40 to 28%. Results of the bed material and fly ash analysis suggested capture of Cu, Pb, Mn, Ni, and Zn in the bed material but also suggested that these metals may be released from the bed if the fuel characteristics or process conditions are changed.

Air Pollution↗
PubMed2006

Chemical speciation of trace metals in seawater: a review.

The recent development of the chemical speciation of trace metals in seawater is described. The speciation studies reveal that metal ion complexation is one of the most important processes in seawater; especially, most bioactive trace metals, such as Fe(III) and Cu, exist as complexes with ligands in dissolved organic matter. The organic ligands in seawater are characterized with metal ions selected by the HSAB concept. A strong organic ligand, which originates from marine microorganisms, is classified as a hard base including carboxylates. The free organic ligand concentrations in seawater are buffered by complexation with excess amounts of Ca and Mg in seawater. The chemical equilibrium model suggested that the concentrations of bioactive free metal ions are at an optimal level to activities of marine microorganisms. For chemical speciation, it is important to have a better understanding of the ecological roles of trace metals in seawater.

Journal Article↗
PubMed2002

Trace metal distribution coefficients in the Mersey Estuary, UK: evidence for salting out of metal complexes.

An examination of partition data for trace metals (Cd, Cr, Cu, Hg, Ni, Pb, Zn) from a number of independent studies conducted in a highly contaminated, organic-rich estuary (Mersey, UK) indicates an increase in the sediment-water distribution coefficient, KD, with increasing salinity for all metals with the excepton of Cd. This behavior is not consistent with inorganic speciation calculations or empirical modeling studies in other estuaries, which predict an inverse relationship between KD and salinity due to competitive adsorption and complexation with seawater ions. The data are, however, well-defined by an empirical model based on the salting out of neutral organic chemicals and yield salting constants in the range 0.7-2.0 L mol(-1). It is suggested that trace metals are complexed by and, subsequently, neutralize organic ligands, and that the resulting neutral assemblages are salted out, possibly via electrostriction. Examination of sorption date from other environments suggests that the effect may be more general in highly contaminated or organic-rich estuaries, and that a specific pool of relatively large, but undefined ligands, is mainly responsible.

Adsorption↗
PubMed2005

Biological factors influencing tissue compartmentalization of trace metals in the deep-sea hydrothermal vent bivalve Bathymodiolus azoricus at geochemically distinct vent sites of the Mid-Atlantic Ridge.

In this study, we investigated on concentrations of trace metals (Al, Cd, Mn, Co, and Hg) in the hydrothermal bivalve Bathymodiolus azoricus, a dominant species at most vent sites along the Mid-Atlantic Ridge (MAR), and in its endosymbiont bacteria and commensal parasite Branchipolynoe seepensis. Comparison of our results with data from the literature on non-hydrothermal bivalves suggests lack of "extreme" uptake of trace metals by B. azoricus, except for Hg concentration which exceeded manyfold previously reported values. Mussels collected from three geochemically distinct vent sites, Menez Gwen, Lucky Strike, and Rainbow, along the MAR showed significant differences in tissue concentration of metals. Proportionality of metals in soft tissues of mussels reflected variation of water chemistry at different vents, which in turn conserved the order of trace metal prevalence in undiluted fluids. There were significant tissue-specific differences in trace metal compartmentalization for all metals investigated. Byssus thread contained the highest metal concentration among examined tissues, and thus it is suggested to be an important detoxification route. Size-dependent differences in metal concentrations were detected only for Hg, revealing a general trend of small mussels accumulating more metal than big mussels. Endosymbiont bacteria are shown to exclusively sequester Al from the host gill and contribute to removal of other toxic metals in mussels from Menez Gwen. The commensal parasite present in all mussels from Lucky Strike had higher tissue concentrations of Mn, Al, and Co than the host gill, unlike Cd and Hg which were considerably lower in the former, and thus its role in detoxification remains unclear. Bioaccumulation potential of vent bivalves and associated organisms are quantified as concentration factors and compared to make inferences on the putative role of the endosymbiont bacteria and the commensal parasite in detoxification of trace metals.

Animals↗
PubMed2005

Comparison of trace metal concentrations in malign and benign human prostate.

Imbalance in the composition of trace metals, recognized to be essential to normal human homeostasis, besides the accumulation of potentially toxic or nonessential trace metals, may cause disease. Thus, there is a need for their analysis in cancerous and noncancerous human tissues to examine the relationship between cancer and these elements. Trace metal concentrations including Cd, Ni, Zn, Cu, Fe, Mg, and Ca in both malign and benign prostate samples were determined by atomic absorption spectrophotometry. The tissues were digested by using microwave energy. In contrast to the literature data for zinc, the concentrations of calcium and zinc in the malign human prostate were found to be significantly higher than those in the benign human prostate (p < 0.05 for both metals). Similarly, the concentrations of iron, nickel, and magnesium in the malign prostate were also found to be higher than those in the benign prostate (p </= 0.1). Therefore, it is understood that more studies are needed regarding the increase or decrease in the metal (particularly Ca and Zn) concentrations of malign prostate samples.

Algorithms↗
PubMed1998

Trace metals and antioxidant enzymes in gills and digestive gland of the Mediterranean mussel Mytilus galloprovincialis.

A seasonal variability of trace metal concentrations and antioxidant enzymes was observed in gills and digestive gland of the Mediterranean mussel Mytilus galloprovincialis from both a polluted and a nonpolluted population. Trace metals (As, Cu, Fe, Mn, Pb, and Zn) exhibited, in both organs, maximum values in later winter-early spring followed by a progressive decrease during the summer. While in the gills this behavior probably reflects a different bioavailability of metals, in the digestive gland it is influenced mainly by the progressive infiltration of the organ by gonadic tissues during gametogenesis. Metals, as other pollutants, are known to influence the oxidative status of these organisms and antioxidant enzymes have been often proposed as biomarkers of exposure to contaminants. In this respect, it was of interest to compare the variations of these biochemical parameters with those of metal levels in two mussel populations from a polluted and a nonpolluted site, respectively. The biochemical parameters examined included the level of glutathione and the activity of the following glutathione dependent and antioxidant enzymes: glyoxalase I, EC 4.4.1.5; glyoxalase II, EC3.1.2.6; glutathione S-transferases, EC 2.5.1.18; glutathione reductase, EC 1.6.4.2; Se-dependent, EC 1.11.1.9 and Se-independent, EC 2.5.1.18 glutathione peroxidases; catalase, EC 1. 11.1.6; superoxide dismutase, EC 1.15.1.1. Seasonal variations of trace metals did not appear to influence those of biochemical parameters, which generally showed an opposite trend with higher enzymatic activities in summer when trace metal concentrations were lower. The effects of metals on antioxidant enzymes were more evident when the two mussel populations were compared. In particular, organisms from the polluted site showed lower levels of glutathione and higher enzymatic activities of glyoxalase I even though the magnitude of these differences was not constant during the year. Moreover, native mussels from both the polluted and control populations exhibited limited differences in the activities of glutathione reductase, glutathione peroxidases, catalase, and superoxide dismutase, suggesting the possibility of some biochemical adaptation in organisms from chronically polluted environments.

Animals↗
PubMed1976

Use of pattern recognition to classify beef cardiovascular tissues on the basis of their trace metal compositions.

The pattern recognition procedure of discriminant analysis has been used to characterize the trace metal profiles created by the concentrations of 8 trace metals in 15 anatomic sites of beef heart tissue. Metals analyzed were copper, tin, lead, molybdenum, strontium, cesium, barium, and aluminum. Anatomic sites sampled included main pulmonary artery, aorta, mitral and tricuspid valves, left and right coronary arteries, os cordis, right atrium, left atrial appendage, crista supraventricularis, left bundle branch, free wall of the right and left ventricles, interventricular septum, and papillary muscle of the left ventricle. The striking features of the data were: (1) All specimens of the mitral valve, tricuspid valve, and os cordis were ambiguously described by their trace metal profiles; (2) the four blood vessels constituted two groups of two tissues each (aorta, main pulmonary artery; left and right coronary arteries); (3) tissues derived from ordinary and specialized myocardium were quite different from blood vessels, heart valves and os cordis. Using these profiles, 85% of the specimens analyzed were correctly classified by discriminant analysis with respect to their anatomic origin.

Aluminum↗
PubMed1999

Monitoring historical changes in soil and atmospheric trace metal levels by dendrochemical analysis.

The use of dendrochemistry for monitoring historical changes in trace metal deposition and mobilisation of metals in soils is evaluated. In experimental studies, mobilisation of trace metals in surface soil following deliberate acidification was recorded in sugar maple (Acer saccharum) tree-rings with minimal lateral movement between rings. Furthermore, positive correlations between wood (3 year section 1993-95) and foliar chemistry (mean concentration 1993-95) were found for Cd and Zn, but not for Cu and Ni, showing that mobility up the tree bole differs between metals. Even so, substantial lateral movement of elements between rings occurs in some species. Stable Pb isotope ratios in tree-rings were used to show that sacred fir (Abies religeosa) is not a useful monitor of Pb deposition because Pb accumulates in the heartwood. Numerous sophisticated analytical techniques are now used in dendrochemical studies, including laser ablation sampling in conjunction with inductively coupled plasma mass spectrometry that enable the multi-element analysis of extremely small tree-rings with low detection limits. Clearly, not all tree species are suitable for dendrochemical studies, but if careful sampling strategies are used and suitable tree species are chosen, the chemical analysis of tree-rings can provide information concerning historical changes in soil and atmospheric trace metal levels unavailable from any other source.

Journal Article↗
PubMedDate not supplied

Relationship of antioxidant enzymes to trace metals in premature infants.

Serum levels of the trace metals copper, zinc, and selenium were measured in premature infants. White blood cell glutathione peroxidase and superoxide dismutase levels were measured in conjunction with the trace metals. Three groups of infants were evaluated: group I was relatively healthy, group II were infants with stage 2 bronchopulmonary dysplasia (BPD) or less, group III were infants with stage 3 BPD or worse. Zinc and selenium levels declined in all groups during conventional parenteral nutrition (TPN) regimens, while copper remained stable. Copper did decline in groups I and II coincident with an acceleration in growth rate. An expected rise in antioxidant enzyme levels in infants with pulmonary oxygen toxicity was not seen. This study suggests that supplemental selenium as well as an increased zinc intake over current recommendations for premature infants receiving TPN may be indicated.

Bronchopulmonary Dysplasia↗
PubMed1979

Histochemical and atomic absorption demonstration of trace metal mobilization in the central nervous system and liver of the rat.

Histochemical and atomic absorption spectrophotometric analysis of trace metal mobilization caused by the action of ethanol in the central nervous system (CNS) and liver of the rat is described. Histochemically it has been shown that in all neurons examined (motoneurons, pyramidal and Purkinje cells) the trace metals (mainly Zn2+ and Cu2+) are mobilized. Most of the stained materials disappear from the perikaryon of the Purkinje cells, while in both the motoneurons and the pyramidal cells the trace metals are displaced from the perikaryon into the axon and axon hillock. At the same time, some of the glia cells display a high metal content. Quantitative determination of the Zn2+ and Cu2+ by means of atomic absorption spectrophotometry reveals that after 2 hours ethanol treatment both the Zn2+ and the Cu2+ levels are decreased in the archicerebellar cortex, while after 4 hours the Zn2+ levels are increased in the cerebrum and the spinal cord. The present observations on the histochemical localization and the contents of zinc and copper in different parts of the CNS and liver reveal the important role of the effect of ethanol on the trace metal mobilization.

Animals↗
PubMed2006

Total petroleum hydrocarbons and trace metals in street dusts from Tshwane Metropolitan area, South Africa.

This study reports the level of total petroleum hydrocarbons (TPHs) and trace metals in dusts from some petroleum handling facilities (gasoline stations), selected high traffic density roads and residential areas within the Tshwane Metropolitan area in South Africa. Total petroleum hydrocarbons in dust samples were extracted using soxhlet extraction and isolated gravimetrically after column cleanup, while total trace metals in dust samples were digested using mineral acid digestion and analyzed using atomic absorption spectrometry (AAS). The mean TPH level from the residential sites ranged from 206 +/- 20.3-300 +/- 36.4 microg g(-1) while those from gasoline stations and high traffic density roads varied between 562 +/- 43.9-340 +/- 62.6 microg g(-1) and 404 +/- 32.7-852 +/- 55.4 microg g(-1) respectively. Mean concentrations of analyzed trace metals at residential areas ranged from 0.04 +/- 0.02-0.07 +/- 0.03 microg g(-1); ND; 0.21 +/- 0.01-0.34 +/- 0.02 microg g(-1); 0.66 +/- 0.06-2.11 +/- 0.82 microg g(-1); 18.7 +/- 0.86-33.4 +/- 0.83 microg g(-1) and 0.07 +/- 0.04-0.23 +/- 0.01 microg g(-1) for Cd, Pb, Cu, Zn, Mn and Cr respectively. Mean levels from gasoline stations ranged between 0.05 +/- 0.02-0.17 +/- 0.07; 0.08 +/- 0.02-0.12 +/- 0.04; 0.21 +/- 0.04-4.34 +/- 0.60; 7.44 +/- 0.40-13.0 +/- 0.56; 23.36 +/- 4.37-131 +/- 10.5 and 0.05 +/- 0.02-0.17 +/- 0.05 microg g(-1) while those from high traffic density roads ranged from 0.07 +/- 0.04-0.10 +/- 0.04; ND-0.30 +/- 0.05; 0.67 +/- 0.05-3.80 +/- 0.82; 2.40 +/- 0.25-10.6 +/- 0.96; 19.8 +/- 1.03-108 +/- 4.44 and 0.06 +/- 0.02-0.12 +/- 0.04 microg g(-1) also in the above metal order. Contamination by TPH and trace metals both at gasoline stations and high traffic density roads is revealed by their significantly higher values compared to those of residential areas.

Cities↗
PubMed2005

Multielement determination of trace metals in river water (certified reference material, JSAC 0301-1) by high efficiency nebulization ICP-MS after 100-fold preconcentration with a chelating resin-packed minicolumn.

The determination of 34 trace metals in a river water certified reference material (CRM), i.e. JSAC 0301-1, which was issued by the Japan Society for Analytical Chemistry in January 2004, was performed by ICP-MS with a high efficiency nebulizer after preconcentration with a laboratory-made chelating resin-packed minicolumn, with which trace metals were concentrated 100-fold from 50 mL of a river water sample to 0.5 mL of the final analysis solution. Trace metals in JSAC 0301-1 were observed in the concentration range from 19 microg L(-1) of Al to 0.000053 microg L(-1) of Bi. It was found that most of the concentrations of trace metals, including rare earth elements (REEs), in JSAC 0301-1 were lower than those in JAC 0031, which was also a previously issued CRM prepared with water from the same river as that of JSAC 0301-1. The low concentrations of trace metals in JSAC 0301-1 might be attributed to the fact that there was a heavy rain before collecting the original water sample to prepare the present CRM. Furthermore, the REE distribution patterns of JSAC 0301-1, JAC 0031 and the average values of river water samples in Japan were parallel to each other. These results indicate that the distributions of REEs in JSAC 0301-1 and JAC 0031 were the typical ones of river water samples in Japan.

Journal Article↗
PubMed1975

Partitioning of trace metals in selective chemical fractions of nearshore sediments.

A series of chemical extraction procedures are used to obtain data on the partitioning of trace metals among the various geochemical phases of sediments. These components include intersititial water, solubility of solid minerals, ions on exchange sites, metal carbonates, easily reducible phases, organics and sulfides, iron oxides, and lithogenous (mineral residual) fractions. In general, a mass balance of less than 10% deviation can be obtained. Experimental results show very small fractions of trace metals to be in the form of interstital water or soluble ions. Trace metals in the exchangeable phase are almost negligible, and those in the mineral residual phases range from 2.5% Cd for one sediment to 98% Cu for another. The non-residual trace metals content is found to increase with decreasing sand content.

Acetates↗
PubMed1997

Assessment of trace metal distribution and contamination in surface soils of Hong Kong.

An intensive investigation was conducted to study the distribution of trace metals in surface soils of Hong Kong and to assess the soil environmental quality. From results of cluster analysis, and comparisons among soil types and areas, it is clearly shown that increases in trace metal concentrations in the soils were generally extensive and obvious in urban and orchard soils, less so in vegetable soils, whilst rural and forest soils were subjected to the least impact of anthropogenic sources of trace metals. However, some of the forest soils also contained elevated levels of As, Cu, and Pb. Urban soils in Hong Kong were heavily polluted by Pb from gasoline combustion. Agricultural soils, both orchard and vegetable soils, usually accumulated As, Cd, Cu, and Zn originating from applications of pesticides, animal manures, and fertilizers. In general, trace metal pollution in soils of the industrial areas and Pb pollution in the soils of the commercial and residential areas were obvious.

Journal Article↗