Showing papers on "Trace metal published in 1978"

Growth limitation of a coastal diatom by low zinc ion activity

Abstract: THE total zinc concentration in unpolluted marine waters has been reported to be in the 10−10 M range1. Such low concentration of an essential micronutrient suggests that the growth of some phytoplankton may be zinc limited. Of the trace metals necessary for phytoplankton growth, only iron has been considered a potential limiting micronutrient in the marine environment2,3. On the basis of laboratory work which focused mostly on copper, it is well known that the toxicity of a trace metal depends on its chemical speciation and can be related uniquely to its free ion activity4,5. However, it has not been established unequivocally that the availability of some metals may also be controlled by their free ion activities and may thus be depressed by organic complexation. Here we report laboratory experiments demonstrating that the zinc ion activity (rather than the total zinc concentration) can limit the growth rate of a coastal diatom Thalassiosira weissflogii (Grun. = T. fluviatalis Hust.) and that the limitation occurs at zinc ion activities which would be present in unpolluted seawater if any organic complexation of zinc were taking place.

Trace metal-chelator interactions and phytoplankton growth in seawater media: Theoretical analysis and comparison with reported observations 1

Abstract: Effects of trace metal chelators in seawater are examined theoretically in terms of equilibrium chemical speciation in seawater; of chemical interactions between all metals, naturally occurring ligands, and added organic chelating agents of various binding strengths and total concentrations; and of transfer of trace metals to the phytoplankton cell surface. An equilibrium model involving 18 metals and 8 ligands is applied to find the metal species in natural seawater, chelator-amended seawater, and synthetic seawater media. Three mechanisms for enhanced supply of iron via chelation are examined: transport through the membrane, ligand exchange at the cell surface, and increased supply of iron to the cell surface by dissociation of a chelate. None account for the observed effects of chelator variations on growth rate. Detoxification of toxic metals via chelation shows a strong correlation between growth rate and free Cu/sup 2 +/ computed at equilibrium in solution.

The distribution of Cd, Cu, Pb and Zn in the biota of two freshwater sites with different trace metal inputs

Abstract: The concentrations of Cd, Cu, Pb, and Zn were determined in the abiotic and biotic components at two sites in the Fox River, Illinois. Analysis of the metals was completed on solutions of wet ashed or dry ashed samples with a single beam atomic absorption spectrophotometer. Despite different inputs of the trace metals there were no significant differences in the concentration of Cu or Zn in the biota between the two sites. This was postulated to be due to physiological control of these metals. However, Cd and Pb concentrations were higher in the biota and substrate at the high input site. No accumulation of Cd or Pb occurred at higher trophic levels. Cu and Zn concentrations were similar for all biota with the exception of crayfish and snails which had higher Cu and Zn concentrations, respectively.

Field investigation of trace metals in groundwater from fly ash disposal

Abstract: A ponded flyash disposal site is studied in detail. Emphasis is on the extent of trace metal migration in groundwater from natural seepage. The investigation is conducted at Northern Indiana Public Service Co.'s Michigan City coal-fired generating station. Trace metals are released into the groundwater in low concentrations. (3 diagrams, 10 graphs, 21 references, 6 tables)

Survey of Trace Metal Contents of Suspended Matter in the St. Lawrence Estuary and Saguenay Fjord

Abstract: Trace metal contents (Mn, Zn, Pb, and Cd) of suspended particulate matter were measured in the upper St. Lawrence estuary and Saguenay fjord. In the estuary, elution of the trace metal fraction adsorbed on particles seems to be mostly responsible for the significant differences in concentrations observed at the freshwater–saltwater boundary. In the Saguenay fjord, particles from deep waters are enriched with trace metals, especially Mn, compared with those from surface waters. This enrichment is probably due to Mn oxidation and simultaneous scavenging of the other trace elements. High Pb and Cd levels in particles of surface waters of the fjord seem to depend mostly on their high affinity for the rich organic matter. Key words: trace elements, suspended matter, estuaries, manganese, zinc, lead, cadmium

Trace metal enhancement in the biotic and abiotic components of an estuarine tidal front

Abstract: A frontal system of lower Delaware Bay was investigated to illustrate the role that such tidal fronts can have in concentrating trace metals and serving as a means for introducing trace metals into the trophic hierarchy of estuaries. This frontal system typically develops on ebb tide and can extend at least 32 km parallel to the central axis of Delaware Bay. In relation to samples collected on either side of the front, chlorophyll a concentrations and concentrations of selected trace metals in zooplankton, particulates, and the dissolved fraction were significantly higher in samples collected at the front. Seasonally, concentrations of cadmium and copper in all fractions were highest during the summer or fall. Differences in taxonomic composition of zooplankton assemblages, as well as differences in total numbers of organisms across the front, suggested advective transport by convergent water masses.

The distribution of rare earth, precious metal and other trace elements in Recent and fossil deep-sea manganese nodules

Abstract: Four deep-sea manganese nodules and one fossil nodule from Timor have been analysed for 45 elements (major elements, rare earths and precious metals) by X-ray fluorescence, spark source mass spectrometry and neutron activation analysis. Co-existing sediments from two nodule sites in the Southwestern Pacific Basin have also been analysed. Differences in nodule composition are apparent, particularly for the Timor nodule. The trace metal compositions of this nodule, however, reveals it to be a typical deep-sea nodule, although some element redistribution has clearly taken place since exposure of the nodule on land. The distribution of a number of elements including Tl, Ir, Pd, Au and the rare earth elements between deep-sea nodules and their associated sediments appears to be dependent on a number of factors including the major element composition of the nodule (e.g. dilution by the silicate phase of the nodule), the differing stability of various element complexes in seawater, and the influence of differences in redox states on complex stability. Au and Si, on the other hand, are positively correlated in nodules and sediments possibly because they have a common source, either submarine detritus or basalt-seawater interaction. The rare earth contents of the sediments from the N.E. sector of the Southwestern Pacific Basin are high compared with previous determinations of rare earths in marine sediments and show no evidence of Ce depletion relative to La on a shale-normalised basis. These high contents reflect the well oxidised conditions and low sedimentation rates of this environment.

Trace Metal Analysis of Water Containing Humic Substances by X-ray Fluorescence

Abstract: Chelation by oxine followed by adsorption on activated carbon results in the efficient collection of many trace metal ions, independent of the trace metal concentration and of high alkali and alkaline earth ion abundances. Preconcentration factors around 10000 are often achieved. When this preconcentration procedure is combined with energy-dispersive X-ray fluorescence, accurate and precise analysis can be carried out, as was proven in several experiments. The technique can also be applied for the determination of divalent ions in natural waters containing up to 10 ppm of humic substances. Trivalent ions can quantitatively be collected from natural water provided suKicient activated carbon is added. Omitting the oxine chelation prior to the activated carbon adsorption step still results in collection of a sometimes important fraction of the trace metal ions from natural waters. This is related to organically bound or colloidal forms of the trace metals.

Trace-metal pollutants and urban-tree leaf pathogens

Abstract: The leaf surfaces of urban trees are contaminated with particles containing numerous trace metals. Six of these metals — Al, Fe, Mn, Ni, Pb and Zn — were evaluated in a doseresponse test with the following fungi isolated from the phylloplane of mature, urban London plane trees; Aureobasidium pullulons, Chaetomium sp., Gnomonia platani and Pleurophomella sp. At low dosage none of the metals was inhibitory to linear growth of any fungus in plate culture, except low dosage inhibition of Chaetomium by Zn. Aluminum and Fe were generally fungitoxic, but only at high dosage. Direct inhibition of leaf-surface fungal growth by trace metal foliar contaminants thus appears unlikely.

Trace metals in some fish species of South Carolina.

Abstract: Samples of fish from freshwater and saltwater sources of ocean, rivers, and lakes over the state of South Carolina were collected. The fish collected were Shrimp, Silver Snapper, White Bass, Catfish, Mudfish and Trout. The sample flasks were incubated in a constant temperature stirring water bath at 58 degrees C until clear solution in reagent-grade nitric acid. Triplicate samples of fish muscle tissue were analyzed by wet digestion and dry digestion methods. Trace metal levels were determined by flame atomic absorption using a Perkin-Elmer Model 306 spectrophotometer. Mercury determination was made by Coleman MAS-50 mercury analyzer. A significant finding of this report is that saltwater fish have more trace metal levels than freshwater fish, and larger fish have higher trace metals than smaller fish. Iron and zinc levels were much higher in Shrimp than any other species analyzed.

Cycling of trace metal and chlorinated hydrocarbon wastes in the southern california bight

Abstract: Trace metals and chlorinated hydrocarbons are two important types of wastes released to the marine ecosystem off southern California. Municipal wastewater discharge is the dominant route of entry for most of the metals investigated. However, the use of vessel antifouling paints, primers, and corrosion-preventing anodes apparently can cause order of magnitude increases in metals levels for both harbor waters and mussels. Invertebrates living near highly-contaminated sediments around a major coastal municipal outfall concentrate certain metals up to ten times natural levels; in contrast, little abnormal uptake was measured in several species of fish from this region. In the past, municipal wastewater has also been the dominant source of chlorinated hydrocarbons to the Bight; however, between 1972 and 1975 these emissions decreased by an order of magnitude, and dry aerial fallout is now an equivalent input route. Despite these reductions, DDT and PCB levels in the highly-contaminated sediments and flatfish from the largest outfall zone decreased by only about a factor of 1.5 during the same period. This indicates that release of these synthetic organics to nearshore marine sediments can lead to persistent contamination of coastal ecosystems. Harbor mussels collected near sites of vessel activity in 1974 and 1977 were also contaminated by PCB's, containing up to twenty times the concentration found in coastal specimens.

Concentration of three toxic metals in oysters (Crassostrea virginica) of biloxi and pascagoula, Mississippi estuaries

Abstract: Concentrations of three toxic trace metals, Hg, Pb, and Cd in the commercial oyster Crassostrea virginica were measured by atomic absorption spectrophotometry. Oysters were collected from the Biloxi, Ocean Springs and Pascagoula, Mississippi area. Mercury concentrations were low and appeared to be natural background levels. Lead content of the Mississippi oysters compared favorably with levels in Atlantic Coast oysters, but Cd in Atlantic Coast oysters was approximately 6.7 times greater than in the local specimens. There was no definite relation between oyster size and Pb, Hg or Cd content.

Mineral and trace metal supplement for use with synthetic diets based on comminuted chicken.

Abstract: Earlier studies (Alexander et al., 1974; Lawson et al., 1977) suggested a suitable composition for a mineral and trace metal supplement for use with synthetic diets containing some natural food. Such a mixture has been evaluated in patients receiving a diet based on comminuted chicken and has been shown to be adequate. This conclusion was based on balance experiments measuring Zn, Cu, Mn, Fe, Ca, Mg, N, and P.

Analytical Acceptability of Trace Metal Levels Found in Oceanic Waters Around Australia

Abstract: Vertical profiles of trace metal levels in the water column for 16 oceanographic stations around Tasmania were determined using anodic stripping voltammetry (ASV) at a mercury-coated graphite electrode (MCGE), a rotating disc glassy carbon electrode (RDGCE) and atomic absorption spectrophotometry (AAS). Cadmium, copper, lead, and zinc were determined by ASV, and iron and nickel were determined by AAS. Variation occurred between MCGE and RDGCE results in the samples analysed for cadmium, copper, lead, and zinc. Statistical analyses of the concentrations found indicated that variations were more likely to be due to procedural blank fluctuations than to change in concentration with depth. For the AAS analyses of nickel, some variation in concentration with depth was apparent after consideration of procedural blanks. However, this variation follows a random scatter pattern.

Foliar feeding organometallic composition

Abstract: Disclosed is a foliar feeding spray composition for supplying trace metals to plants comprising a thermally-treated trace metal chelate dissolved in a hydrocarbon mineral oil carrier having a minimum gravity API of 27, a viscosity at 100° F. of between 55 and 100 Saybolt Universal Seconds, a boiling point range of between about 600° F. and 775° F. and a minimum unsulphonated residue content of 85%, the thermally-treated chelates being present in an amount ranging from 0.05 to 12.0 percent basis oil.

Geochemical aspects of atmospherically transported trace metals over the Georgia Bight

Abstract: There has been considerable evidence in recent years that a significant portion of the trace metals reaching coastal waters are transported by the atmosphere. The present study had the following three purposes: to assess trace metal concentrations and enrichment factors in the nearshore atmosphere over the Georgia Bight between Charleston, South Carolina and Jacksonville, Florida; to determine the sources of the metals; and to evaluate the solubilities of some of the metals in seawater. Atmospheric trace metal concentrations and enrichment factors generally decrease from Charleston to Jacksonville. Five metals (Cd, Zn, Cu, Ni, and Pb), were found to be anomalously enriched over the Georgia Bight. Observations from this study suggest that seawater may influence Cu and Zn concentrations in Georgia Bight air. Solubilities of Zn and Cu in seawater are source dependent, as seen by correlation with EF/sub crust/. No significant solubility of Ni in seawater was observed. Yearly fluxes of eight trace metals from atmosphere to seawater in the Georgia Bight were estimated. These trace metal fluxes are comparable to fluxes in other areas along the east coast. The fluxes of Cu, Cd, and Zn make considerable contributions to dissolved metal levels in Georgia Bight water. An attempt tomore » use trace metal concentrations in Spanish mosses as a means of tracing sources of trace metals over the Georgia bight was inconclusive.« less

Sampling Design for Some Trace Elemental Distributions in New York Bight Sediments

Abstract: The paper outlines a model to describe the spatial distribution of selected trace elements (chromium, copper, nickel, lead, and zinc) in New York Bight sediments. Empirical tests of the fit of existing data by means of cumulative probability plots on log-normal probability paper and goodness-of-fit tests demonstrate conformity to the log-normal distribution predicted by the model. An adaptive sampling strategy for describing the spatial distribution of the trace elements is developed, based on a knowledge of the sampling distributions of the elements. The spatial distribution of the sampling stations conforms to the expected nonuniformity of the trace metal concentrations of interest, providing for a more efficient allocation of sampling effort.

Contemporary and historical trace metal loadings to the sediments of four lakes of the Lake Washington drainage. Completion report

Abstract: Contemporary and historical loadings of lead, zinc, and copper to the profundal sediments of Lakes Washington, Sammamish, Chester Morse, and Findley were determined using chemical analysis and /sup 210/Pb dating of sediment cores. Elemental sedimentation rates, a cross product of the sedimentation rate, and sediment concentration of a given element, were corrected for natural background concentrations and rates, and extrapolated across established sediment accumulating areas to give a conservative estimate of the pollutional trace metal loadings to each lake. The resulting chronological loadings appeared consistent with the known cultural history of the individual watersheds. Substantial alterations in sedimentation rates were noted in all lakes where deforestation, road building, suburbanization or urbanization had occurred in the lake's watershed. The quantities, elemental ratios and pollutional histories of copper, lead and zinc in the lake sediments indicate that aeolian inputs are the dominant source of trace metal pollution to the lake sediments at the present time.

Trace metals especially Fe+++ as dietary factors for leafhoppers

Abstract: Some trace metals are required for development and reproduction, and therefore for continuous rearing of the aster leafhopper,Macrosteles fascifrons, on a holidic diet. Requirement for Fe+++ becomes apparent immediately in the 1st generation; for Cu++ and Zn++, in the 3rd. The leafhopper has grown normally and continuously for 3 generations in the absence of manganese.