Showing papers on "Trace metal published in 1986"

Effect of Sequence in Extraction of Trace Metals from Soils

Abstract: While many workers have utilized various reagents for sequential extraction of soil trace metals, few studies have examined the order of extraction for key steps in the sequential procedure In this study, several sequences involving both adsorbed and structural (occluded) metal extractants were evaluated to determine the most appropriate sequential methodology for extracting different forms of Cu, Fe, and Mn For "specifically adsorbed" metals, Pb(NO3)2 and CH3COOH were used The results showed that the former reagent extracted less Cu, Mn, and Fe and was probably more specific in replacing metals covalently bound to adsorption sites Lead nitrate was therefore placed before CH3COOH extraction in the sequence Chao's NH2OHHCl reagent and K4P2O7, used for Mn oxide and organic metal removal, respectively, were found to solubilize significantly different amounts of Cu and Mn depending on sequence, with K4P2O7 extracting more metal when used first As NH2OH • HCl has little effect on organic metals, it should be used before K4P2O7 Noncrystalline and crystalline Fe compounds are solubilized next, using a variety of reagents, and residual (silicate lattice) metals are dissolved in the final step A nine-step sequential method is proposed to characterize trace metals in agricultural, polluted, and wasteamended soils Additional Index Words: sequential extraction, trace metal fractionation, soil Cu, soil Mn, soil Fe View complete article To view this complete article, insert Disc 4 then click button8

Toxic metals in the atmosphere

Abstract: Emission Factors of Atmospheric Elements (J. M. Pacyna). Atmospheric Trace Elements from Natural and Anthorpogenic Sources (J. M. Pacyna). Sampling and Measurement of Trace Element Emissions from Particulate Control Devices (A.D. Shendrikar & D. S. Emsor). Smelting Operations and Trace Metals in Air and Precipitation in the Sudbury Basin, (W. H. Chan & M. A. Lusis). Emissions and Air Quality Relationships for Atmospheric Trace Metals (G. R. Cass & G. R. McRae). Quantitative Source Attribution of Metals in the Air Using Receptor Models (P. K. Hopke). Trace Metals in the Atmosphere of Rural and Remote Areas (G. B. Wiersma and C. I. Davidson). Trace Metals in the Arctic Aerosol (N. Z. Heidam). Chemical Elements as Tracers of Pollutant Transport to a Rural Area (L. Husain). Chemical Speciation and Reaction Pathways of Metals in the Atomspere, (R. M. Harrison). Characterization of Trace Metal Compounds in the Atmosphere in Terms of Density (A. Sugimae). The Sizes of Airborne Trace Metal-Containing Particles (C. I. Davidson & J. F. Osborn). Metal Solubility in Atmospheric Deposition (D. F. Gatz & L.-C. Chu). Impact of Atmospheric Inputs on the Hydrospheric Trace Metal Cycle (W. Salomons). Atmospheric Toxic Metals and Metalloids in the Snow and Ice Layers Deposited in Greenland and Antarctica from Prehistoric Times to Present (C. F. Boutron). Monitoring the Atmospheric Depostion of Metals by Use of Bog Vegetation and Peat Profiles (W. A. Glooschenko). Mercury Vapor in the Atmosphere: Three Case Studies on Emission, Deposition, and Plant Uptake (S. E.. Lindberg). Biogeochemical Cycling of Organic Lead Compunds (W. R. A. De Jonghe & F. C. Adams). Airbone Lead in the Environment in France (J. Servant).

Sorption of trace metals by humic materials in soils and natural waters

Abstract: Trace metal sorption by coagulated humic acid and peat materials can be described macroscopically either as a complexation or a cation exchange phenomenon. Model equilibrium constants or selectivity coefficients for trace metal sorption by H‐form humic materials are special cases of two general models which do not depend on the sorption mechanism. Sorption mechanisms can be elucidated by spectroscopic techniques, both optical and magnetic resonance, but no information about mechanisms can be inferred from equilbrium constants.

Response of Radioactive Trace Metals to Acid–Base Titrations in Controlled Experimental Ecosystems: Evaluation of Transport Parameters for Application to Whole-Lake Radiotracer Experiments

Abstract: Radiotracer experiments were carried out in 20 enclosures located in two lakes at the Experimental Lakes Area (ELA), northwestern Ontario, to study pathways of trace metal removal from the water column of shallow lakes. Two removal mechanisms were characterized: (1) sorption to and subsequent transport with falling particles and (2) direct adsorption to surface sediments. Our approach was to measure independently the kinetics of radiotracer sorption, fluxes and concentrations for particles, particle settling velocities, and the "equivalent stagnant boundary film." Our radiotracer results enabled us to test the sensitivity of the tracer removal rates on these rate-determining processes using a numerical transport model. Acid titrations of whole ecosystems revealed that some trace metals (e.g. Mn, Co, and Zn) can diffuse back to the water column as the pH is lowered from 6.5 to 4.8 after 18 d, while others remain tightly bound (e.g. Sn, Fe, Se, Cr, Ag, and Hg isotopes). Subsequent CaCO3 additions to bring b...

Effect of seasonally changing tissue weight on trace metal concentrations in the bivalve Macoma balthica in San Francisco Bay

Abstract: The influence of seasonal changes in the weight of soft tissues on temporal fluctuations in tissue concentrations of Cu and Zn was examined in 4 populations of the clam Macoma balthica sampled in San Francisco Bay for a period of 2 to 5 yr. Fluctuations in metal concentration expected from changes in tissue weight between sampling dates were estimated by assuming that whole body metal burden was constant during the sampling interval. Comparison of estimated and actual metal concentrations showed that the degree to which fluctuations in trace metal concentrations were driven by weight changes d~ffered considerably among stations, among years at a single station, and between metals.

Concentration and deposition of trace metals in Ontario-1982

Abstract: Results of trace metal concentrations in air and precipitation and the corresponding wet and dry deposition in Ontario in 1982 arc reported. In terms of the spatial patterns, in general, there was a decreasing gradient from south-to-north in both concentration and deposition. Patterns differed with each parameter although certain groups of metals (e.g., Fe and Al; Pb, Zn, and Mn) displayed similar patterns. In general, wet deposition was greater than dry deposition at all sites. Geographically, the variability in the wet to dry deposition ratio for coarse particles (MMD > 2.5 μm) was small. However, it increased from the south to the north for fine particles (MMD < 2.5 μm), being higher away from the source areas. Scavenging ratios (W) have been derived from the precipitation and air concentrations of trace metals. The scatter in W is quite large for all trace metals, up to 2 orders of magnitude. There was little seasonal variability in W for fine particles (Pb, Mn, Zn, and Cd). However, coarse particles (Fe, Al, and Cu) were more efficiently scavenged by snow than by rain.

Trace metal solubility in salt marsh sediments contaminated with sewage sludge

Abstract: As part of a study to investigate the effect of nutrient and metal pollution on salt marshes, a sewage sludge fertilizer has been applied to experimental plots in Great Sippewissett Marsh, MA, since 1974. The concentration of nutrients, soluble sulfides, and metals were measured in porewater from these plots every 4–6 weeks from April to December in 1980. Metal and nutrient concentrations in these plots were consistently greater than in corresponding control plots. Nutrients stimulated growth of Spartina alterniflora, the dominant vegetation on these plots, and higher grass production increased sediment oxidation. Concentrations of soluble sulfide in fertilized plots were an order of magnitude lower than in surrounding areas. For much of the year sulfides could not be detected in porewater from surface sediments of fertilized plots. The solubility of metals in sediments in fertilized plots was greatly increased by the decrease in sulfide concentrations. For much of the year, the top 4 cm of the sediments in fertilized plots were undersaturated with respect to all metal sulfide minerals. This undersaturation may account for the large loss of metals observed on these plots. It appears that in the surface sediments of these plots the retention of metals may be governed in part by adsorption onto iron oxyhydroxides. Precipitation of metal sulfides may be important in limiting the penetration of metals deeper into the sediment. At 6 cm, Zn and Cd were always close to the solubility of their respective sulfide minerals. Below 4 cm, iron was undersaturated with respect to all iron monosulfide minerals but supersaturated with respect to pyrite. Copper was supersaturated with respect to CuS and Cu2S in all samples where sulfide was above the detection limit. Gel filtration experiments indicated that significant amounts of iron and copper were organically complexed in the porewater and may have been partially responsible for the large supersaturations.

Trace metal monitoring of pelagic organisms from the open Mediterranean sea

Abstract: During the periods 1974–75 and 1977 mixed microplankton and individual species of macrozooplankton and nekton were sampled from a number of areas in the mediterranean Sea in order to establish baseline levels of selected trace elements in pelagic species from the open Mediterranean. Trace elements analyzed were Ag, As, Cd, Co, Cs, Cu, Fe, Hg, Mn, Rb, Sc, Se, V, and Zn. Variability for concentrations of many of the trace elements was high, and broadly speaking if trace element concentrations in all species examined from any one area in the Mediterranean are considered, no general regional differences in element levels were evident. On the other hand, metal concentrations in certain individual pelagic species did suggest limited regional variations. No significant differences between metal concentrations in organisms collected in 1974–75 and 1977 were noted. For most of the elements, similar data for the same species collected in other years do not exist, therefore at present it is not possible to establish temporal trends for metals in pelagic Mediterranean organisms. Comparison of these results with data reported for similar species from other oceanic regions suggests that metal levels in open ocean organisms are no higher in the Mediterranean than elsewhere. It is concluded that long-term, open ocean ecological monitoring programmes, while useful and possible to carry out technically, may be severely limited by the high costs of shiptime and lack of long-term commitment and financial support from both national and international bodies.

Trace metal distribution in different chemical fractions of nearshore marine sediments

Abstract: The major objective of this study was to carry out sequential chemical extractions for the partitioning of particulate trace metals in sediment samples, collected from False Bay Eight metals, Cd, Cu, Cr, Fe, Mn, Ni, Pb and Zn, were examined in each of 65 samples Three chemical fractions of the sediments were separated and the concentrations of the trace metals were determined in each, by atomic absorption techniques The three different leaches used were hydroxylamine hydrochloride-acetic acid, hydrogen peroxide, and nitricperchloric acids Fe and Pb were concentrated mainly in the fraction extracted by nitric-perchloric acid, while Cu, Zn and Ni were found mainly in the peroxide fraction Most of the metals in the peroxide phase were found in the finer sediments in the central area of the bay, where the concentration of organic meterial was high The metal concentrations (except for Pb) correlated well with the organic content of the sediments

Zinc Cu, Ni and Cd in the forest floor in the Northeastern United States

Abstract: A regional study was conducted to assess current levels of trace metals in the forest floor, and to establish a baseline for future studies of metal accumulation. Quantitative forest floor samples collected from 78 sites in 9 states in the northeastern United States in 1978 and 1980 were analyzed for Zn, Cu, Ni, and Cd. Mean amounts present in the forest floor were 9.8 ± 1.9 (standard error of the mean), 1.7 ± 0.2, 0.86 ± 0.08, and 0.13 ± 0.01 kg ha−1, for Zn, Cu, Ni, and Cd, respectively. Mean concentrations were 133 ± 25, 19.5 ± 1.6, 11 ± 0.8, and 1.7 ± 0.1 mg kg−1, respectively. Differences in metal and organic matter concentrations and amounts among forest types were attributed to geographic location of specific forest types rather than to direct biotic influence. No element was strongly correlated with elevation for the entire sample area. Regional patterns of elemental amounts showed that trace metal levels are slightly higher in the southern part than in the northern part of the study region. Regional variation of Zn, Cu, Ni, and Cd in the forest floor was not indicative of atmospheric deposition except near point sources of pollution.

The geochemistry of trace metals in the Brazos River estuary

Abstract: A seasonal study of trace metal behavior and transport in the Brazos River estuary was conducted in the winter, spring and fall of 1981. Surface water was analyzed for total dissolved Pb, Cu, Mn and Fe, and particulate Cd, Pb, Cu, Mn and Fe. Ancillary data included river discharge, total suspended matter, pH, major ions, nutrients, dissolved and particulate organic carbon and humic acid. The major ions were generally conservative across the river water-seawater mixing zone; however, a significant input of alkalinity and Ca was measured in the spring, attributable to cation exchange on clays and sediment diagenetic processes. Distinct concentration maxima were found in the 3–10‰ chlorinity range for dissolved Pb (0·06–0·9 n m ), Cu (6–42 n m ), Mn (2–290 n m ) and Fe (5–80 n m ). Particulate metal concentrations showed significant seasonal and spatial variations: Cd, 0·09–0·57 ppm; Pb, 15–43 ppm; Cu, 12–32 ppm; Mn, 250–1990 ppm and Fe 0·5–5·4%. Reducing conditions leading to diagenetic remobilization in estuarine sediments are proposed to be an important source of dissolved metals for estuarine water. Calculations of dissolved riverine metal transport to the ocean that include estuarine metal input are as much as 40 times greater than when estuarine processes are ignored.

Mn, Fe, Cu and Cd distributions and residence times in closed basin Lake Vanda (Wright Valley, Antarctica)

Abstract: Mn, Fe, Cu, and Cd concentrations are reported for Lake Vanda, a closed-basin, meromictic, Antarctic lake and for its single major inflow, the Onyx River. Trace metal distributions in the upper lake and annual metal fluxes from the Onyx River were used to estimate chemical residence times in the mixed zone above the chemocline. Residence times, based on total metal loads, were 9.4 years for Mn; 1.4 years for iron; 174 years for copper; and 82 years for cadmium. Controls on the steady state concentrations of metals in this system are likely to include: particle settling of Fe and Mn; scavenging of minor elements on metal oxide surfaces; sulfide precipitation from the anoxic brine; and possibly uptake of metals on the surface of benthic algal mats. Model calculations show that metal removal by sinking phytoplankton can account for only a small fraction of the annual loss.

Trace metals in mussels (Mytilus edulis) from the Waddenzee, coastal North Sea and the estuaries of ems, Western and Eastern Scheldt

Abstract: Since 1979 the trace metal content of mussels in the Netherlands has been monitored as part of the Joint Monitoring Program for the assessment of the level of marine pollution and the effectiveness of measures taken for its reduction. The Joint Monitoring Program includes the coordinated monitoring activities of the Conventions of Oslo (1972) and Paris (1974). The results of the Dutch contribution are given in this paper.

Trace metal concentrations in marine organisms from St. Vincent Gulf, South Australia

Abstract: Trace metal concentrations were measured in the tissues of fish, molluscs, crustaceans and macrophytes from St. Vincent Gulf, South Australia. The concentrations of the measured metals (Cd < 0.025 to 2.1 μg g−1; Cu 0.51 to 9l μg g−1 5 Pb 0.02 to 3.6 ⧎g g−1; Zn l5 to 110 μg g−1)are similar to those from unpolluted areas and thus give no indication of pollution.

Variation in trace metal exports from small Canadian shield watersheds

Abstract: Annual exports of Cu, Pb, and Cd were estimated for eleven headwater and two lake outflow streams in the District of Muskoka, Ontario, Canada. COCl2-APDC coprecipitation coupled with anodic stripping voltammetry was used to determine metal concentrations. Concentrations of all three metals were similar to those reported from other temperate forested ecosystems, being usually less than 1 ug L−1 with Cd undetectable (<25 ng L−1) in many samples. There was limited evidence for a spring peak in metal concentrations associated with the snowpack melt. Annual export (mass per unit area per year) of each metal was calculated; variability between streams was small. Exports of Pb appear to be related to the organic content of the water. Copper export was correlated with watershed area, not with organic acids, implying that a different transport mechanism and possibly a different source are important for this metal. The exports of Pb and Cu were much lower in all streams than the estimated annual atmospheric metal depositions reported for this area in the literature. Terrestrial retention was higher than 95% for all catchments, while lake retention was slightly lower in some cases. Despite the small fractional loss of trace metal from the watersheds, terrestrial inputs can comprise a significant portion of the total metal load to typical lakes in this region because of size of the catchments relative to the lake areas.

Air to Sea Transfer of Anthropogenic Trace Metals

Abstract: There is more and more evidence that, at least in the Northern hemisphere, the atmospheric cycles of some trace metals, especially heavy metals such as Pb, Cd, Sb, As, Sn, are now strongly perturbed by human activities (Andreae et al., 1984). How such a geochemical perturbation in the atmosphere interacts with the oceanic cycles of these elements is a matter of crucial interest since many trace metals are both essential for the development of marine life and potentially toxic for marine life above certain concentration levels. This induced shift of the cycles of some trace metals in surface and deep waters from a steady to a transient state offers also the perspective of using new oceanic tracers for improvements in ocean circulation models. Such a shift is still extremely difficult to model because of the lack of accurate knowledge of a) the temporal and spatial distribution of the atmospheric deposition of these elements b) the scale of anthropogenic perturbations in the atmosphere and c) the biogeochemical processes which drive the fate of trace metals in the ocean.

Manganese and antibiotic biosynthesis. I. A specific manganese requirement for patulin production in Penicillium urticae

Abstract: The effect of trace metal nutrition on the functioning of the patulin biosynthetic pathway in submerged cultures of Penicillium urticae (NRRL 2159A) was examined by both chromatographic and enzymol...

Beaufort Sea monitoring program: analysis of trace metals and hydrocarbons from Outer Continental Shelf (OCS) activities. Final report, 1983-1986

Abstract: An environmental-monitoring program, designed to detect and quantify long-term changes in sediment and tissue concentrations of metals and hydrocarbons potentially due to oil and gas exploration and development on the U.S. Beaufort Sea continental shelf, was initiated in 1984. In Year-1 of the three-year study, a series of benthic stations was established in the nearshore area between Barter Island and Cape Halkett. In Year-2 of the study, areal coverage of the Study Area was increased to 39 marine stations and 10 shoreline and river stations. Analysis of six replicate sediment samples for trace metals, and saturated and aromatic hydrocarbons revealed a wide range of concentrations. Both trace metal and hydrocarbon analyses of bivalve and crustacean tissues indicated concentrations differences between species but no apparent relationship between animal body burdens and sediment concentrations.