Trace Metal Profiles Research Articles

A new teflon sampler for trace metal studies in seawater — ·wates’

A 2.3-1 sampler is described which passes the atmosphere/water interface in a closed position, so that the enclosed water is only in contact with easily cleaned PTFE (polytetrafluoroethylene). This seems to minimize contamination risks for investigations on trace metals, e.g. mercury, in deep, open ocean waters where it is often several hours before the samples can be drained into pre-cleaned bottles suitable for further treatment and storage. Five trace metal profiles determined in 1983 at stations in the Bay of Biscay are tabulated and preliminary interpretations made to demonstrate the suitability of the new sampling device.

Diagenetic trace-metal profiles in Arctic lake sediments

Heterogeneous trace-metal profiles have been found in the slowly accumulating sediments of Toolik Lake, AK. Elevated Ba, Co, Cu, Mo, and Ni concentrations near the sediment-water interface are inconsistent with inputs from recent watershed disturbances. The apparent cause of trace-metal enrichment is comigration with Mn and Fe in pore water resulting in narrow bands of trace-metal enrichment associated with high (>15%) concentrations of Mn and Fe. The misinterpretation of diagenetic enrichments as anthropogenic features is a potential problem in mildly reducing, Mn- and Fe-rich lake sediments.

Trace metal enrichments in the Mediterranean Sea

Copper, nickel, and cadmium occur at higher concentrations in the surface waters of the Mediterranean than in nutrient-depleted waters of the open ocean. Trace metal profiles have been taken on both sides of the Strait of Gibraltar to constrain a mass balance. Deep Mediterranean waters have trace metal levels comparable to surface waters in regions of Mediterranean deep water formation, implying a minimal role for vertical transport by biological activity. Excess trace metals are not present in open-Atlantic source waters, but a detailed map of trace metal distributions in the Alboran Sea (immediately east of the Strait) reveals a metal-enriched plume with concentrations as high as copper, 3.6 nmol/kg; nickel, 2.8 nmol/kg; and cadmium, 120 pmol/kg. A substantial enrichment in trace metal concentrations therefore can occur in transit from the open Atlantic through the coastal zone into the Strait. This trace metal enrichment may derive either from river inflow (masked by evaporation), diffusion out of continental shelf sediments, eolian particulate fallout, or anthropogenic sources. Metal sources (fluvial, sedimentary, or atmospheric; natural or anthropogenic) are difficult to discern from the large-scale oceanographic distribution. Metal retention in nutrient-depleted surface waters is not due to unusual metal fluxes relative to nutrients, but instead is a consequence of less frequent recycling of nutrients in the Mediterranean compared to the open ocean. Metal enrichments would be expected before human intervention, with anthropogenic input reflected in proportion to the relative augmentation of inputs over natural levels. Mediterranean water produces small trace metal anomalies in the outflow core (positive for Ni, negative for Cd). Present observations are consistent with this prediction, but high precision data would be necessary to observe these at distance from Gibraltar.

Trace metals and radium in the Gulf of Mexico: An evaluation of river and continental shelf sources

Several studies have provided evidence for the enrichment of trace elements in coastal waters, particularly for copper. These enrichments have been attributed to diffusion from continental shelf sediments and to an influx of river water. We attempted to resolve between these sources by undertaking an extensive suite of measurements of trace metals (Cu, Ni, Cd), 226Ra and 228Ra in the surface waters of the Gulf of Mexico, along with trace metal profiles at 6 stations (April 1981 and December 1982). These data establish that enrichments of copper, nickel and cadmium occur in the shallow waters of the Gulf of Mexico. On the Mississippi continental shelf, high trace element concentrations (Cu, Ni: ∼ 9 nmol/kg; Cd: ∼ 200 pmol/kg) in lower-salinity waters (26‰) are similar to those observed in the Mississippi plume at the same salinity. This evidence suggests a river water source. On the other hand, trace element enrichments are also observed in the northern Gulf (Cu: +0.4 nmol/kg; Ni: +0.5 nmol/kg; Cd: +20 pmol/kg) which coincide with an increase in 228Ra but are not accompanied by decreased salinity. The excess of evaporation over precipitation in this region makes it possible that this water could be evaporated estuarine water; therefore, hydrographic observations cannot distinguish readily between river and shelf sources. A regional flux balance shows that most of the excess copper in the surface waters of the Florida Current can be supplied by the river-borne dissolved copper flux. Within the uncertainties of such calculations, the continental shelf copper flux must be less than or equal to the river flux.

Trace Metal Profiles in the Forest Floor of New England

AbstractPrevious studies in New England have revealed high levels of trace metals in the forest floor of remote regions and evidence of increases in trace metal concentrations and amounts over time. In this study, forest floor profiles collected from a boreal forest in Vermont, a northern hardwood forest in New Hampshire and white pine (Pinus strobus L.) stands in Massachusetts were analyzed for Pb, Cu, Zn, Ni, Cd, and organic matter. Concentrations of Pb, Cu, Zn, Ni, and percent organic matter showed similar trends with depth in all three forests. Cadmium occurrence differed according to site. Concentrations of Pb, Cu, Zn, and Ni were greatest 2 to 4 cm below the surface of the forest floor in all three forests. As expected, percent organic matter decreased with depth in the profile. Concentration and accumulation of trace metals appear to occur in the Oe horizon.

The Distribution of Selected Trace Metals in United Kingdom Shelf Waters and the North Atlantic

The distribution of dissolved and suspended particulate Cd, Cu, Mn, Ni, and Zn was surveyed in the water of the North Atlantic and adjacent European shelf seas. The exercise was conducted by the Lowestoft Fisheries Laboratory and was part of a broad program coordinated by the International Council for the Exploration of the Sea (ICES) Working Groups concerned with pollution baseline and monitoring studies. The distribution of dissolved metals was enriched in coastal waters up to an order of magnitude compared with the offshore shelf seas. Both anthropogenic and natural sources of metal were considered in relation to the elevated inshore values. The suspended particulate phase of trace metals present in coastal and shelf waters was often a significant proportion (between 5 and 70%) of the total metal present. Oceanic values of dissolved metal were comparable with concentrations measured in offshore shelf seas. Deep vertical profiles of trace metals resembled the distribution of nutrient salts, thus indicating biological mobilization. The validity of all data was discussed in relation to current sampling and analytical techniques. The degree of sampling and analytical sophistication employed must relate to the basic requirements of the exercise.

Anthropogenic Changes in Organic Carbon and Trace Metal Input to Lake Washington

An example of how man's contaminants are introduced, deposited, and retained in sediments giving a chronological record of events has been developed for Lake Washington, Seattle. Significant amounts of both inorganic and organic compounds in the environment originate from fossil fuel sources, such as power plants and motor vehicles. Many organic compounds are introduced also from contemporary biogenic materials. Through the combined carbon isotope analysis technique (CCIA), we can distinguish between fossil and contemporary carbon sources classes (using14C), as well as sources within each class (using13C). To establish the chronology of the organic carbon pollutant input to the lake sediment, the ages of the layers were determined using210pb dating techniques. Sediment profiles of trace metals and a fallout radionuclide plutonium were also obtained and compared with the carbon isotope profiles. The results show that the total organic carbon (TOC) concentration correspond to 93% modern carbon before 1905. This14C concentration in TOC decreased to ∼60% modern in the 1930's and now is between 95 and 80% modern. The lipid fraction is ca 30% modern and the total aromatic hydrocarbon fraction reached a minimum of 5% modern in 1954. The large decrease in14C of TOC around 1930 is believed to be due to coal dust or fly ash. The trace metal concentration also increased substantially at this time. The pattern observed in the sediment thus reflects the change in the local energy consumption pattern from a predominately coal to an oil-based economy. From the plutonium profile we infer that mixing occurs for 3 or 4 years before the sediment layers are compacted.

Anthropogenically derived changes in the sedimentary flux of magnesium, chromium, nickel, copper, zinc, mercury, lead, and phosphorus in Lough Neagh, Northern Ireland

The concentration-depth behavior of Mg, Cr, Ni, Cu, Zn, Hg, Pb, and P in three sediment cores from a central site in Lough Neagh, Northern Ireland, was examined for changes in the sedimentary flux of these elements. Two main periods of change were found. A change in the catchment erosion-leaching regime in the 17th century, caused by widespread and comprehensive woodland clearance, produced increased sedimentary Mg, Cu, and Pb concentrations. A second and larger change occurred after about 1880 A.D. Cr, Cu, Zn, Hg, Pb, and P, and , to a lesser extent, Ni concentrations increase toward the sediment surface. Differing P and trace-metal profiles, a comparison of the estimated anthropogenic sedimentary flux with background atmospheric contributions, and a general comparison with other situations all suggest that background atmospheric sources make a substantial contribution to the more recent Cu, Zn, Hg, and Pb sedimentary contamination. The trace-metal contamination of Lough Neagh is part of a global pattern.

Polarized Zeeman-effect flameless atomic absorption spectrometry of cadmium, copper, lead, and manganese in human kidney cortex.

We used polarized Zeeman-effect flameless atomic absorption spectroscopy to quantitatively measure cadmium, copper, lead, and manganese in a nitric acid digest of lyophilized human kidney cortex. Within-run coefficients of variation for cadmium, copper, lead, and manganese, 15.3, 177.2, 84.2, and 56.3 microgram/L, respectively, were 4.1, 6.3, 3.7, and 5.6%, respectively. Between-run coefficients of variation were 6.9, 5.5, 5.9, and 6.3%, respectively, for cadmium, copper, lead, and manganese concentrations of 135.1, 12.8, 2.72, and 3.80 microgram/g, respectively. For cadmium, copper, lead, and manganese digest concentrations (mean +/- SE) of 15.3 +/- 0.6, 41.4 +/- 2.6, 9.4 +/- 0.6, and 20.9 +/- 0.4 microgram/L, respectively, the detection limits were 5.2 microgram/L for copper, 1.2 microgram/L for both cadmium and lead, and 0.8 microgram/L for manganese. Assays were linear to 75 microgram/L for cadmium, 100 microgram/L for manganese, and 200 microgram/L for copper and lead. Average analytical recoveries for the four metals ranged between 95 and 101%. Because these metals were quantitated in the same digest of kidney cortex, the values for each digest gave a trace-metal profile for each autopsy specimen.

Geochemical Evidence for Modern Sediment Accumulation on the Continental Shelf off Southern New England

ABSTRACT An area of fine-grained sediment approximately 170 km 74 km in size, located in water depths between 60 m and 150 m, south of Martha's Vineyard, Mass., is a site of modern sediment deposition. The 14C ages systematically increase with sediment depth from about 1,300 years B.P. at the surface to 8,000-10,000 years B.P. at the depth of maximum core penetration. The old age for the surface sediments probably results from a combination of deposition of old carbon and faunal mixing. In the finest sediments, the sedimentation rates were approximately 130 cm/1,000 yrs when deposition began and have decreased to about 25 cm/1,000 yrs. The decreasing sedimentation rate reflects a diminishing source of fine sediments, which presuma ly came from the Georges Bank and Nantucket Shoals area. Inventories of excess 210Pb in undisturbed cores average 70 dpm/cm2 (disintegrations per minute per square centimeter), more than two times higher than the flux of 210Pb from the atmosphere and from 226Ra decay in the overlying water. This additional influx of 210Pb either must be with new fine-grained sediment material or from solutions that are stripped of their 210Pb by particulates in the bottom nepheloid layer. Stable Pb concentrations in surface sediments are about 28 ppm, as much as two times higher than concentrations at depth. The high accumulation rates, 210Pb inventories, and trace-metal profiles imply that this area is a modern sink for fine-grained sediments and for pollutants associated with particulate matter in the water column. To our knowledge, this is the only site of present-day natural deposition on the Continental Shelf off the eastern United States, exclusive of the Gulf of Maine. Because the net currents on the outer half of this Continental Shelf flow from northeast to southwest, this fine-grained deposit may receive its sediments and possible contaminants from the Nantucket Shoals and Georges Bank regions.

Distribution of 9 trace metals in 17 anatomic sites of dog heart tissue and their classification using pattern recognition

The concentrations (geometric means of 11 determinations) of 9 trace metals in 17 anatomic regions of dog heart tissue and blood vessels were determined. The relationships recognized within the set of trace metal profiles were comparable to those reported earlier for the cardiovascular systems of pig [ J. Mol. Cell. Cardiol. 6, 383 (1974)] and those of beef [ Bioinorg. Chem. ( in press)]. These included differences in trace metal concentrations that allowed differentaition of the following tissues from each other: (1) ordinary and specialized myocardium from blood vessels and heart valves, (2) blood vessels from heart valves and (3) arterial from venous tissues.

Analysis by pattern recognition techniques of changes in serum levels of 14 trace metals after acute myocardial infarction

Serial changes in the concentrations of 14 trace metals (Cu, Fe, Al, Ni, Sr, Ba, Mn, Cs, Sn, Cr, Zn, Pb, Mo, and Cd) in blood serum of patients who had sustained an acute myocardial infarction and in patients who had sustained other cardiac trauma were determined by emission spectrometry. Comparable data for both patient groups were obtained for the serum enzymes, creatine phosphokinase, glutamic oxaloacetic transaminase, and lactic dehydrogenase. Multivariate analysis of variance indicated that changes in serum levels of copper, iron, aluminum, and nickel during the first 7 days following an acute myocardial infarction might be useful in the classification of patients. Using such a trace-metal profile, the discriminant analysis technique of pattern recognition provided almost complete (91%) success in distinguishing the two patient groups. Complete discrimination was achieved when the covariates age, race, and sex were included pairwise with the four trace metals, Cu, Fe, Al, and Ni. The studies suggest that trace metals may play an important role in cardiovascular metabolism and the chemical pathology of myocardial infarction.

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.

Novel classification scheme of cardiovascular tissues using trace metal compositions

Statistical methods of pattern recognition have been employed to characterize the trace metal profiles created by the concentrations (the geometric means of 11 determinations) of 13 trace metals for 17 anatomic regions of pig heart tissue. Metals analyzed were zinc, copper, tin, aluminum, lead, cadmium, manganese, molybdenum, nickel, strontium, barium, cesium and chromium. Anatomic sites sampled included main pulmonary artery, aorta, mitral valve, tricuspid valve, aortic valve, pulmonary valve, right superior vena cava, right atrium, sinus node, crista supraventricularis, left bundle branch, atrioventricular node and His bundle, left ventricle-papillary muscle, right ventricle (free wall), left ventricle (free wall), interventricular septum, and left atrial appendage. Both techniques of pattern recognition used, namely cluster analysis and discriminant analysis, recognized similar relationships among the tissues, including differences between: (1) arterial and venous tissues; (2) semilunar and atrioventricular valves; and (3) tissues derived from ordinary and specialized myocardium and those derived from blood vessels and heart valves. The pulmonary valve was found to concentrate many trace metals relative to other anatomic sites. The differences among the tissues were sufficiently striking that, using the profiles, 65% of the specimens analyzed were correctly classified with respect to their anatomic origin.