Showing papers on "Trace metal published in 1989"

Natural trace metal concentrations in estuarine and coastal marine sediments of the southeastern United States

Abstract: Over 450 sediment samples from estuarine and coastal marine areas of the southeastern US remote from contaminant sources were analyzed for trace metals. Although these sediments are compositionally diverse, As, Co, Cr, Cu, Fe, Pb, Mn, Ni, and Zn concentrations covary significantly with aluminum, suggesting that natural aluminosilicate minerals are the dominant natural metal bearing phases. Cd and Hg do not covary with aluminum apparently due to the importance of the contribution of natural organic phases to their concentration in sediments. It is suggested that the covariance of metals with aluminum provides a useful basis for identification and comparison of anthropogenic inputs to southeastern US coastal/estuarine sediments. By use of this approach sediments from the Savannah River, Biscayne Bay, and Pensacola Bay are compared.

Preparation and chemistry of the artificial algal culture medium aquil

Abstract: The culture medium Aquil has been designed for studying trace metal physiology in algae. We describe recent modifications in the preparation of Aquil and discuss processes that affect its trace metals and their physiological effects. The major changes in Aquil preparation are purification of the Chelex column to avoid contamination by chelating agents, use of alternative sterilization procedures, and increases in the concentration of trace metal buffers. During growth, phytoplankton take up trace metals, thus continuously reducing their concentrations in the medium. Algae can also modify the redox state and degree of organic complexation of trace metals through the direct and indirect activity of cell surface enzymes and the release of metabolites. Illumination of the culture medium necessary to promote photosynthesis also promotes a variety of photochemical reactions that alter the chemistry of the medium and maintain it in a state of disequilibrium. In particular, light absorption by FeEDTA lead...

The Use of Extractants in Studies on Trace Metals in Soils, Sewage Sludges, and Sludge-Treated Soils

Abstract: When the main problems of trace metals in the soil were deficiencies, it was usually sufficient to know how much of an essential trace metal was “available” to an extractant, usually acetic acid, ethylene diamine tetracetic acid (EDTA), diethylene triamine pentacetic acid (DTPA), etc. (e.g., Lindsay and Norvell, 1969; Viets and Lindsay, 1973; Ministry of Agriculture, Fisheries and Food, 1981). This is fortunate because the soil chemistry of trace metals is rarely simple, and it is particularly obscure at deficiency levels, when even the least unavailable trace metal ions are held on “specific sites” whose character is difficult to establish or define, rather than in identifiable salts (Lindsay, 1979).

Geochemistry of recent TOC-rich sediments from the Gulf of California and the Black Sea

Abstract: Major and minor elements (incl. Ag, As, Ba, Cd, Co, Cr, Cu, Mn, Mo, Ni, Pb, Sr, V, Zn) have been determined in recent sediments from the Gulf of California upwelling area and Black Sea sapropels in order to reinterpret their chemical composition in view of reliable seawater and plankton data. The chemistry of the Gulf of California sediments reflects regeneration processes which occur in the water column; i.e. only a small fraction (<10%) of elements like Cd, which in seawater are coupled to the »labile« nutrients (C, N, P), is buried in the sedimentary column. In contrast, elements like the more resistant nutrients (Si) undergo a deeper regeneration cycle (Ba). Several trace metals which are present in comparatively higher concentrations in seawater (As, Mo, U, V) and at the same time are reactive under reducing conditions and/or are able to form stable Sulfides, are fixed in the sediments during early diagenesis. The early diagenetic behavior of Ba is closely related to bacterial sulfate reduction. The formation of barite concretions is discussed. Anoxic conditions in the water column act as ideal traps for a number of redox sensitive and/or stable sulfide forming elements. A simple trace metal balance calculation shows that the chemical composition of Black Sea sapropels is controlled by fluvial and Mediterranean seawater element input and the accumulation rate of terrigenous detrital material.

Control and fate of atmospheric trace metals

Abstract: I Presentations.- Natural Versus Anthropogenic Emissions of Trace Metals to the Atmosphere.- Technological Parameters Affecting Atmospheric Emissions if Trace Elements from Major Anthropogenic Sources.- Control of Heavy Metal Emissions from Waste Incinerators.- A Tiered-Profile Approach to a Global Trace Metal Emission Inventory.- Modelling the Atmospheric Transport of Trace Metals from Europe to the North Sea and the Baltic Sea.- Elemental Source-Receptor Techniques for Precipitation and Aerosol: Recent Experiences from Narragansett, Rhode Island.- On the Spatial Representativeness of Trace Element Ratios.- Statistical Methods to Apportion Heavy Metals.- Dry Deposition of Trace Elements.- Wet Deposition of Heavy Metals.- Behavior of Cd, Mn, and Pb in Forest - Canopy Throughfall.- Analytical Techniques for Atmospheric Trace Elements.- Cycling of Mercury in the Environment with Enphasis on the Importance of the Element in Acid Rain Studies.- Atmospheric Transformations of Trace Metals: Evidence for Aerosol Sulfur Association with Metals from Soil Minerals in Eastern North America and the Potential for Solubilization of Aluminium and Iron Before Deposition from the Atmosphere.- Biomonitors of Air Pollution by Heavy Metals.- II Working Group Summaries.- Technology Related to Sources of Heavy Metals and the Abatement Thereof.- Modelling Trace Element Transport.- Research Needs in Understanding Processes of Transformation, and Dry and Wet Deposition of Atmospheric Metals.- Special Topics Concerning Interactions of Heavy Metals with the Environment.

Trace metal associations in the water column of South San Francisco Bay, California

Abstract: Spatial distributions of copper (Cu), zinc (Zn) and cadmium (Cd) were followed along a longitudinal gradient of dissolved organic carbon (DOC) in South San Francisco Bay (herein referred to as the South Bay). Dissolved Cu, Zn and Cd concentrations ranged from 24 to 66 nM, from 20 to 107 nM and from 1·2 to 4·7 nM, respectively, in samples collected on five dates beginning with the spring phytoplankton bloom and continuing through summer,1985. Dissolved Cu and Zn concentrations varied indirectly with salinity and directly with DOC concentration which ranged from 2·1 to 4·1 mg l−1. Available thermodynamic data strongly support the hypothesis that Cu speciation may be dominated by association with dissolved organic matter. Analogous control of Zn speciation by organic complexation was, however, not indicated in our computations. Computed free ion activity estimates for Cu, Zn and Cd were of the order of 10−10, 10−8 and 10−10 M, respectively. The availability of these metals may be among the factors regulating the growth of certain phytoplankton species within this region of the estuary. In contrast to dissolved Cu, dissolved Cd was directly related to the concentration of suspended particulate matter, suggesting a source of dissolved Cd coincident with elevated particle concentrations in the South Bay (e.g. runoff and solute desorption). Consistent with work in other estuaries, partitioning of all three trace metals onto suspended particulates was negatively correlated with salinity and positively correlated with increases in particulate organic carbon associated with the phytoplankton bloom. These results for the South Bay indicate that sorption processes influence dissolved concentrations of these trace metals, the degree of this influence varies among metals, and processes controlling metal distribution in this estuary appear to be more element-specific than spatially- or temporally-specific.

Chemical Properties of Metal-Humic Acid Fractions of a Sewage Sludge-Amended Aridisol

Abstract: Humic acid (HA) was extracted from a Domino soil (Xerollic Calciorthids) cropped with barley (Hordeum vulgare L.) and sorghum [Sorghum bicolor (L.) Moench] in experimental plots that received applications of sewage sludge for 4, 5, 6, or 7 yr at rates of 0,22.5, 45, or 90 Mg ha⁻¹ yr⁻¹. The HA samples were characterized chemically by elemental and functional group analyses, total trace metal content, infrared (IR), and electron spin resonance (ESR) spectroscopy. As compared to the nonamended Domino (Xerollic Paleorthids) soil HA, the highest sludge-amended soil HA was extracted in higher yields and had higher N and S contents, lower C/N molar ratios, higher total acidity and phenolic OH content, lower organic free radical content, and higher relative intensity of the amide I and amide II IR absorption bands. These differences are believed to be caused by the incorporation of components typical of the applied sludge organic fraction into the soil HA, i.e., proteinaceous materials, sulfur-containing compounds, and phenolic components. The HA also exhibited a well-defined selectivity in respect to trace metal adsorption/desorption. Copper, Ni, Zn, Fe, and Cr were adsorbed strongly onto readily available sites, or through exchange with more weakly adsorbed trace metal ions (Mn, V, Ti, and Mo). However, the soil HA tended to reach metal saturation at the highest sludge application rates. The ESR analysis showed the presence of indigenous Cu²⁺, Fe³⁺, and VO²⁺-HA complexes in all HA samples. These complexes had similar chemical and structural properties, and were concluded to represent the speciation of the metals in association with HA. In general, the impact of the organic constituents in fresh sludge on the soil HA appeared to be mitigated somewhat by the continual tendency of soil organic matter to attain equilibrium, whereas the metal-organic portion of the soil HA was significantly affected by sludge application. Contribution from the Dep. of Soil and Environ. Sci., Univ. of California, Riverside.

Natural Versus Anthropogenic Emissions of Trace Metals to the Atmosphere

Abstract: The emissions from anthropogenic sources now exceed the flux from natural sources, implying that mankind has become the key element in the regional and global cycle of most of the trace metals. The source inventories presented suggest that the Mn/V, Mn/Sn and Mn/Ni ratios are the most useful tags of air pollution from the burning of fuel oil while the Mn/Mo ratio can be regarded as best suited for fingerprinting the contributions from coal combustion. In future, the emissions of trace metals from refuse incineration and the contributions from the developing countries are expected to be of growing concern. Biogenic processes are recognized in this report as being particularly important in the natural flux of trace metals into the atmosphere.

Comparison of different pre-concentration methods for the determination of trace levels of arsenic, cadmium, copper, mercury, lead and selenium

Abstract: Three methods have been considered for trace metal concentration: (a) liquid-liquid extraction using either ammonium pyrrolidinedithiocarbamate or 8-hydroxyquinoline-5-sulphonic acid; (b) the use of a synthetic poly(dithiocarbamate) resin; and (c) reductive precipitation with NaBH4. The suitability of method (a) for the determination of metal ions in samples with a complex matrix and high salinity has been investigated. Method (b) was especially useful for speciation studies of trace levels of AsIII, AsV, SeIV and SeVI. Method (c) gave 1000-fold pre-concentration factors with total recoveries.

Trace Metals Volatilisation in Fluidised-Bed Combustion and Gasification of Coal

Abstract: Coal contains most trace elements in the periodic table which are released by combustion and gasification and have tonic forms at certain concentrations. For metals namely: cadmium (Cd), lead (Pb), mercury (Hg) and zinc (Zn) were selected and multicomponent, multiphase equilibrium calculations were carried out for atmospheric and pressurised fluidised-bed operating conditions to determine which of the metals volatilise in the bed and which ones condense upon cooling the flue gases. It was also intended to determine the distribution and the form (compounds) of the trace metal species in the product streams. Some of the results are analysed and compared with the trace-metal content of atmospheric and pressurised fluidised-bed combustor effluent streams.

Trace metal impurities in silica as a cause of strongly interacting silanols

Abstract: The paper describes nuclear activation analysis of several chromatographic grade silicas for the determination of trace metals. The effect of acid washing is described and the effect of trace metals on the acidity of surface silanols is discussed. A correlation has been found between the concentration of metal traces in the layer of silica adjacent to the surface and the concentration of strongly interacting sites.

The Trace Metal Geochemistry of Suspended Oceanic Particulate Matter

Abstract: : Vertical profiles of suspended particulate trace metals were measured in the Sargasso Sea near Bermuda and in the California Current, northwest Pacific. Using a new in situ pump, sufficiently large samples of particulate matter (order 10mg) were collected to allow measurement of a suite of trace metals as well as major component elements, using several different leaching techniques on separate subsamples. Concentrations of particulate Copper, Zinc, Cobalt, Cadmium, Nickel, and Lead near Bermuda were determined to be substantially lower than estimates based on previously published work. Concentrations of the more abundant elements Aluminum, Fe, and Mn were similar to previous estimates. Vertical profiles of Mn, Co, Pb, Zn, Cu, and Ni (mol/l) at Bermuda displayed similar features: a relative depletion in surface waters, a relative maximum in the upper thermocline, and relatively constant deep water concentrations. The similarity in the vertical variations of dissolved/ particulate fractionation for these metals may be caused by interaction of dissolved metals with authigenic Mn phases; the fractionation is anti-correlated with other major particle components (organic carbon, calcium carbonate, opal, and aluminosilicate). The vertical profile of particulate Cd displayed a different form: enrichment at the surface and decreasing concentrations through the thermocline to constant deep water values. Theses.

Trace metal content of six Arabian Sea fish species using a direct nitric acid based wet oxidation method

Abstract: A simple wet oxidation procedure, based on the use of nitric acid alone is presented for the estimation of trace metals in marine fish by atomic absorption method. Six Arabian sea fish species, salmon, tuna, silver pomfret, black pomfret, lontail tuna and Indian Oil‐sardine were analyzed for their trace metal content. The nearshore fish species caught off the Karachi coast were analyzed for nickel, copper, manganese, mercury, iron, chromium, cadmium, lead, zinc and arsenic. The results are quoted at ±S confidence level and are compared statistically with those attained by common wet oxidation and dry ashing methods in terms of standard deviation and coefficient of variation based on replicate measurements.

Dissolved and particulate trace metals in a wetland of international importance: Lake Mikri Prespa, Greece

Abstract: This paper reports the dissolved and particulate trace metal distributions in Lake Mikri Prespa, wetland of NW Greece. The concentrations of Cu, Pb, Zn, Cd, Al, Fe, Mn, Ni and Cr were determined in surface and hypolimnetic waters as well as in the inputs and the outflow. Trace metals were connected with two major populations of suspended particles, identified by using the recovery ratio for two different leaching reagents, namely 0.5 N HCl and 1:1 hot aqueous HNO3. The first group is land derived entering the lake through runoff and plays a rather restricted role in its geochemistry. The second group which is more important includes authigenic carbonates, Fe and Mn hydroxides and oxides and organic rich particulates.

Trace Metal Interactions Involving the Intestinal Absorption Mechanisms of Iron and Zinc

Abstract: The basis for absorptive trace element interactions is given by the statement of Hill & Matrone (1970) that “those elements whose physical and chemical properties are similar will act antagonistically to each other biologically” Although the direct antagonistic competition of chemically-alike metals is a straightforward concept, an important associated view is that dietary preconditioning with an excess or deficiency of an element may reveal interactions with the metabolism of chemically-similar metals