Showing papers on "Trace metal published in 1980"

Trace metal analysis on polluted sediments

Abstract: Sediment analyses are used to pin‐point major sources of metal pollution and to estimate the toxicity potential of dredged materials on agricultural land. For source assessments (Part I of the present review) standardization is needed with respect to grain size effects, commonly achieved by analyzing the sieve fraction <63μm. Further aspects include sampling methods, evaluation of background data and extent of anthropogenic metal enrichment.

Trace metal analysis on polluted sediments: Part II: Evaluation of environmental impact

Abstract: Sequential extraction techniques are used to determine the chemical associations of heavy metals with specific, sedimentary phases, whereby the potential, availability of toxic compounds for biological uptake may eventually be estimated. The importance of such investigations in the classification of dredged materials is rapidly increasing. As in the case for the reduction of grain size effects (see Part I of the present review) a methodological standardization appears to be presently of special import. Available methods are discussed and a simplified scheme composed of two major extraction steps (acidified hydroxylamine and hydrogen peroxide) is proposed.

Geographical and seasonal variations in the relationship between trace metal content and body weight in Mytilus edulis.

Abstract: The relationships between trace metal content (Cd, Cu, Fe, Mn, Ni and Zn) and body weight of Mytilus edulis L. show that smaller mussels are richer in trace metal than larger ones. According to the metal, the season and the locality examined, 3 types of relationships were obtained: (1) straight lines over the whole size range of mussels; (2) curves with steeper slopes in larger mussels and (3) curves with lowering slopes in larger mussels. For most metals the slopes changed from one locality to another. A detailed analysis of the relationship between Cd content and body weight showed a gradual decrease in metal content until maturity was reached, thereafter the relationship varied significantly with the season, and 2 different types of curves were obtained. Thus, our results contradict the idea that slopes are uniform for a given metal and species. Multivariate analyses showed that weight accounted for most of the variance in metal content while age and gonad maturation explained little of the variance observed. We propose the metabolic changes associated with sexual maturity and season continually change the relative importance of the circulating and storage compartments of metals and may be responsible for the variations of slope observed.

Heavy metal inputs to Mississippi Delta sediments

Abstract: Heavy metal concentrations were determined in suspended particulates, filtered water and sediment collected in the Mississippi River and from its marine delta. More than 90% of the metal load of the river is associated with particulate matter, which is relatively constant in chemical composition with time and place. The Mississippi River suspended material is similar to average crystal rocks in Fe, Al, V, Cr, Cu, Co, Mn, and Ni concentration but is generally enriched in Zn, Cd and Pb. Sediment cores dated by the Pb 210 method show that the Cd and Pb enrichments are recent phenomenon and are most likely due to the activities of man. About 6000 tonne of Pb and 300 tonne of Cd are being added to the delta sediments by man each year, more than 30 times the amount added to the Southern California Bight. River particulate matter is essentially identical to deltaic sediments in Al, Fe, Cr, V, Cd and Pb concentration, but the sediments are depleted in Co, Cu, Mn, Ni and Zn by 20 to 40%. Chemical leaching of the solids show the metal losses to be primarily from the oxide phase, suggesting diagenetic reduction and mobilization as a mechanism. Trace metal concentrations in filtered Mississippi River water were below the limits for safe drinking water and were similar to world average river values. The abundant river suspended matter and high pH combine to keep dissolved trace metal concentrations low.

Experimental Study of Trace Metal Chemistry in Soft-Water Lakes at Different pH Levels

Abstract: The biogeochemistry of Hg, Zn, Co, Fe, Mn, Cr, V, Th, Ba, Cs, As, and Se in two soft-water lakes of the Canadian Shield was investigated by means of carrier-free γ-emitting isotopes introduced into limnocorrals in which the pH of the water was varied from 6.8 to 5.1. The residence times of the radionuclides in the water were determined, and the partitioning of the nuclides among different metal-binding agents in the water and sediments was studied with the aid of membrane filtration, dialysis, solvent extractions, and fractionation on Sephadex columns.Metal behaviour varied systematically with metal properties. Metals of high crystal field stabilization energy, high electronegativity, or small ionic radius were most readily scavenged by> 0.45 μm suspended particles and dispersed colloids in the water, disappeared most rapidly from the water column, and were preferentially accumulated by sedimentary binding agents, including organic substances. Which property of a metal had the dominant effect on metal beh...

Trace Metals in Health and Disease

Abstract: Trace elements often have a bimodal or even a trimodal effect. Severe deficiency of certain trace metals can result in death or severe crippling of an animal or in birth defects of the newborn. The next level of intake is the nutritional level where chronic deficiency over a lifetime may cause major diseases such as cancer and heart disease. The next level of intake is the toxic level which may result in severe crippling or death of the animal. The primary area of concern in this chapter will be the nutritional intake level and the deficiency level and their relationship to animal or human disease. The trace elements described in this chapter are: chromium; cobalt; copper; fluorine; iodine; iron; manganese; molybdenum; nickel; silicon; selenium; tin; vanadium; and zinc.

Trace metal cycling in tropical-subtropical estuaries dominated by the seagrass thalassia testudinum

Abstract: The present study was designed to determine the uptake and release rates of various trace metal cations by turtle grass and its community in order to provide the coefficients of our previously described computer model intended to simulate trace metal cycling in subtropical and tropical estuaries. The site of uptake in Thalassia was also examined. Microcosms of moving seawater at various salinity levels and various temperature levels were used. An equal spike of 22Na, 137Cs, 85St, 84Mn and 65Zn was added to each tank. Samples of seagrass, their epiphytes, macroalgae, animals and substrates were exposed for varying periods. Half of each sample was rinsed in unspiked seawater for a period equal to the exposure to the radionuclides prior to counting. Dried and weighed samples were counted and energy spectra determined. Activity of the different radionuclides was determined by computer analysis. Uptake was found to be asymptotic. Concentration three orders of magnitude larger than in the seawater occurred in seagrass leaves and other biological compartments of the system. Uptake of the lesser soluble radionuclides by subsediment plant parts was much less than by leaves, although the same rhizomes and roots, when exposed directly to the seawater, took up the radionuclides approximately in the same amounts as the blades. The unspiked seawater rinse removed a significant fraction of all the radionuclides taken up by the various biological components. Marine angiosperms take up substances as do terrestrial plants (root uptake) or as marine plants (leaf uptake) and, in addition, significant translocation occurs in either direction, i.e., root to leaf or leaf to root, dependent on uptake site and concentration. Subtropical and tropical populations were compared and temperature and salinity dependencies of uptake were examined. SEAGRASS ECOSYSTEMS are found throughout the world's oceans and are primarily in nearshore shallow waters where the impact of man's activities is most severe. Our attention has been focused on the seagrass systems dom

Marsh plants as vectors in trace metal transport in oregon tidal marshes

Abstract: The role of Pacific coast marsh plants as vectors in the flux of trace metals was studied in natural and perturbated situations. The flux of Cr, Cu, Fe, Mg, Sr, and Zn were studied in natural stands of Carex lyngbyei, Distichlis spicata, Potentilla pacifica, and Salicornia virginica. Seasonal fluxes of trace metals into the shoots of the living plants were measured as was their transfer to the dead plant community through mortality. Disappearance from the latter community (through fragmentation, leaching and excretion) was calculated. Seasonal data were summed to produce annual input-output budgets. The flux varied from 3 mg/n2 for Cr in a stand of Potentilla pacifica to 15,000 mg/M2 for Fe in Carex lyngbyei. The uptake of trace metals from contaminated dredged material was compared with that from natural soils using modified buckets placed in the marsh. Four plants (Carex lyngbyei, Distichlis spicata, Deschampsia cespitosa, and Salicornia virginica) were tested for Cd, Cr, Cu, Pb and Zn. Copper was the only metal accumulated from contaminated soils in the situations tested.

Trace metal cycling in the u.s. coastal zone: a synthesis

Abstract: This synthesis of trace element research in estuarine communities of the U.S. coastline and the Caribbean provides a summary applicable to the shoreline of the tropical and temperate regions of the world which have mangroves, kelp beds, riverine marshes and seagrass communities. An inventory of sediments and leaf tissues shows Mn and Fe to be the most highly concentrated elements with Hg and Cd present in lowest concentrations. Generally, trace element concentrations in roots are much higher than in leaves and other tissues above the sediment. Tissue to sediment concentration ratios show that Cd is most likely to be bioamplified and that Cu, Hg, Sr and Zn may have relatively high concentration ratios which can exceed unity. A conceptual model was constructed to integrate the forcing functions, compartmental couplings, and dynamics common to these estuarine systems. Seasonality is important for changes in some trace element concentrations in plants and litter. Trace element additions to water or sediment increased certain trace element concentrations in plants and dead organic matter. It is clear that estuarine plant communities serve as living filters of estuarine trace elements. However, increased knowledge of trace element cycling in estuarine systems and relationships between trace element concentrations in plants and the estuarine food chain is needed, particularly food chains to man. There is a need for structured long-term estuarine research to allow direct comparison of results among estuarine study sites, to identify the similarity of population and system processes among estuaries and to define the geographical scale over which estuarine research results may be generalized.

Trace metal levels in commercially prepared tissue culture media

Abstract: Four trace elements, lead, copper, tin and zinc, in addition to certain electrolytes, were measured in 11 commercially prepared tissue culture media. Glass media bottles and plastic tissue culture dishes and flasks were treated with a HCl acid solution to determine the amounts of trace metals leached from their surfaces. Zinc, lead and copper were detected in all media. Tin was detected only in RPMI Medium 1640, fetal bovine serum, minimum essential medium and penicillin-streptomycin. It is possible that a major cause of variability in tissue culture experimental results may be due to effects on growth caused by fluctuation in trace element contamination from batch to batch. Variability in establishing primary cultures of corneal endothelial cells was traced to high lead levels in commercially prepared tissue culture media. A strong case is made for continued diligent efforts to expand analytical horizons and our definition of substances in culture media.

Chemical and physical characteristics of precipitation at selected sites in Florida

Abstract: Infrequent sampling of precipitation in Florida has been conducted by the U.S. Geological Survey since 1965. A summary of the historical data from 24 sites throughout Florida indicate that the principal ionic composition of atmospheric precipitation samples is calcium sodium and bicarbonate chloride with an average specific conductance of 32 micromhos per centimeter at 25°C. Historically, much of the sampling focused on primary nutrients and selected trace elements. Historical data indicate that nitrogen and phosphorus concentrations averaged 1.1 and 0.1 milligrams per liter, respectively. The limited trace metal data indicate that motor-vehicle activity may have a significant impact on local precipitation quality. Lead, for example, was measured in concentrations of as much as 2,400 micrograms per liter in samples collected in a highly populated, commercial area in south Florida. Statistical testing indicated that most major inorganic constituents, primary nutrients, and trace metals were significantly different among the sampling sites. The pH data indicated a range of about 5.0 to 7.0, but only limited pH data were collected and analyzed at the historical sites in such a timely manner as to represent pH conditions of the atmospheric precipitation during active rainfall. A critical review of the historical data suggested that while they may reflect local atmospheric quality conditions they likely do not define baseline conditions from a regional perspective. The application of these data was limited regarding regional extrapolation due to variations in sampling techniques, methods of sample preservation, sampling intervals, sample sizes, and periods of record.

Trace Metal Speciation of USGS Reference Sample MAG‐I

Abstract: The USGS reference sample marine mud MAG-1 has been subjected to a sequential extraction procedure designed to partition the constituent trace metals into five fractions: I-exchangeable; II- bound to carbonates; III-bound to Fe-Mn oxides; IV- bound to organic matter; V- residual. The analytical approach involved successive chemical extractions and the subsequent determination of trace metal concentrations (Co, Cu, Ni, Pb, Zn; Fe, Mn) in the leachates by atomic absorption spectrophotometry. The chemical speciation results obtained on four replicate sub-samples demonstrate that the coefficients of variation for metal concentrations in the individual fractions are generally better than + 10%. Comparison with published values for total trace metal concentrations in the MAG-1 sample suggests that the overall accuracy of the chemical extraction procedure is satisfactory.

Voltammetric Determination of the Stability Constants of the Predominant Labile Lead Complexes in Sea Water

Abstract: Traces of heavy metals and other toxic trace metals occur dissolved in the sea mainly in form of labile inorganic complex species with the anionic constituents of sea water as ligands. Therefore, the identification of the preferentially by the respective metal formed complex species, their physicochemical characterization and the determination of their stability constants are important actual topics in marine trace metal chemistry. Suitable polarographic and voltammetric methods, provide a rather unique access to this kind of speciation problems. Experimental data obtained in aqueous model solutions with I of 0.7 and in artificial sea water by single sweep voltammetry and by a particular semiautomated ASV-procedure have established that the two labile complexes of Pb(II) prevailing in the sea are [PbCO 3 ] and [Pb (CO 3 ) 2 ] 2− .

Trace metal geochemistry in sediments from the Miramichi estuary, New Brunswick

Abstract: Organic matter, mineralogy, and texturally-related qualities combine to control the total concentration and reactivity of trace metals in the sediments of the Miramichi estuary. Concentrations of lignin-rich organic matter, up to 10% of the total sediment weight in the central estuary, correlate with analytical results for trace elements which show that more than 40% of the total Mn, Zn, and Cu is held in the oxidizable and organically-bound form. Mineralogical influences are most obvious in the river portion of the system where total Mn concentrations average 695 μg/g, Zn averages 282 μg/g, Cu averages 32 μg/g, and Pb averages 200 μg/g in the less than 63 μm size fraction of the sediments. In the marginal marine Miramichi Bay, total concentrations of these four trace elements in the fine sediment fraction are diminished by 9–57%, with respect to the equivalent size fraction of the river sediments.The concentration of all trace elements in the coarse fraction (> 63 μm) is considerably less as compared wit...