Kathe K. Bertine

Fossil Fuel Combustion and the Major Sedimentary Cycle

The combustion of the fossil fuels coal, oil, and lignite potentially can mobilize many elements into the atmosphere at rates, in general, less than but comparable to their rates of flow through natural waters during the weathering cycle. Since the principal sites of fossil fuel combustion are in the mid-latitudes of the Northern Hemisphere, changes in the composition of natural waters and air, as a consequence of this activity, will be most evident at these latitudes.

Some comparative marine chemistries of rhenium, gold, silver and molybdenum

Abstract Four metals, Re, Au, Ag and Mo, whose dissolved forms in seawater can potentially be reduced to insoluble states, have been measured in a variety of solids depositing under anoxic conditions: hydrothermal sulfides; coastal sediments; and phosphorites. For comparative purposes these elements have also been determined in ferromanganese minerals and pelagic sediments which have accumulated under oxidizing conditions. Rhenium appears to be a unique sentinel for identifying reducing depositional environments, where enrichments of greater than three orders of magnitude above crustal concentrations are found. Molybdenum follows Re in these sediments but Mo is enriched also in those that accumulate under oxidizing conditions. The reported Mo crustal concentrations appear low in comparison to our measured sedimentary values. Gold and Ag are concentrated in hydrothermal deposits and sulfides appear to be involved in the precipitation of these elements. Coastal sediments adjacent to a domestic outfall of Los Angeles, California contain extraordinary high accumulations of anthropogenic Au, Ag and Pt. The study seeks an understanding of the mobilities and sinks of these metals in the marine environment during the major weathering cycle. Further, anthropogenic contributions to their sedimentary concentrations are identified.

The240Pu239Pu ratio, a potential geochronometer

Abstract The Arctic and Antarctic ice sheets maintain records of the atmospheric fallout in their datable strata. The 240Pu239Pu ratios in these polar reservoirs uniquely distinguish particulate fallout from the pre-moratorium nuclear atmospheric weapons tests, dominated by the U.S., and the post-moratorium atmospheric weapons tests, dominated by the U.S.S.R. Thus, they offer the possibility of use as a geochronological tool for some marine, glacial, lacustrine and soil systems.

Magnetite in sediments as an indicator of coal combustion

Abstract Magnetic susceptibility gives an accurate measurement of the magnetite concentration in sediments. In all geographical areas studied, the magnetite concentration in recent lake, estuarine and ocean sediments has been affected by coal burning which releases magnetite spheres to the atmosphere. Graphs of percent magnetite and percent spheres vs depth (age) in the various sediments can be used to give information on the history of coal burning in an area as well as the efficiency of air pollution controlling devices. Chromium, Zn, Ti and Fe concentrations in the sediments were affected by the input of magnetic spheres. Cadmium, Cu, Mn, Ni and Pb concentrations were not affected.

Osmium in marine sediments

Osmium is enriched in ferromanganese minerals, and its concentrations follow those of other Pt-group metals except Pd. Oxidative capture during solid formation is the probable mechanism for uptake. In some sediments forming under reducing conditions (phosphorites and anoxic coastal deposits) there is also an enrichment. This may relate to reductive capture, although deposits also formed under reducing conditions from hydrothermal areas are depleted in osmium.

Comparative marine chemistries of some trivalent metals—bismuth, rhodium and rare earth elements

Abstract The differing marine chemical behaviors of some trivalent elements are compared on the bases of their crustal rock concentrations and of those in various marine compartments. At one extreme, the platinum group element rhodium has a remarkable stability in seawater, perhaps attributable to kinetically hindered complex formation. On the other hand, bismuth is far more reactive as evidenced by its unusual enrichments in ferromanganese minerals and by its depletion in deep waters. The rare earth elements, lanthanum, samarium and lutetium show behaviors intermediate between those of rhodium and bismuth.

Gold in seawater: a conservative view

Abstract Gold concentrations in filtered and unfiltered open ocean Pacific waters give an average of 29 ± 9 pg/l by an atomic absorption/graphite furnace technique preceded by an anion exchange preconcentration step. Similar values (average 37 ± 8 pg/l) were found in nearshore unfiltered waters. These values are geochemically in line with those of golds periodic table neighbors, Pt, Pd and Ag, which also form strong chloro-complexes. On the basis of its more uniform values with depth in seawaters, Au is less reactive in the ocean system than these other metals.

Plutonium isotopes in the environment: some existing problems and some new ocean results

Marine sediments, terrestrial soils and polar glaciers yield different average values for the 240Pu/239Pu ratio resulting from the introduction of the actinide to the environment from weapons tests. The average value of the ratio in two sea water profiles from the North Pacific Ocean is 0·23, which is similar to that calculated from Arctic and Antarctic glaciers but differs considerably from the soil-derived average of 0·18. With the exception of near-surface waters, the sea water values of the 240Pu/239Pu ratio were nearly invariant with depth indicating that plutonium has been homogenized in the water column for a time period of decades. This contrasts with the glacial strata where there were systeamtic changes in the ratio with time of deposition.

Elemental composition of the colloidal phase isolated by cross-flow filtration from coastal seawater samples

Abstract The colloidal fraction was isolated to a solid using cross-flow filtration from 165 1 of Massachusetts coastal seawater taken as part of the WHOI Intercomparison exercise in August 1994. The elemental composition of this sample was determined by ICP-MS. Comparisons to analyses made part way through the isolation process as part of the colloid intercomparison exercise, indicate that loss due to break-through and/or adsorption occurred primarily when the 1-kD Millipore membranes were used to concentrate the colloidal fraction. Retention of the colloidal material was relatively high when the Desalinization membranes were used to concentrate the colloidal material. Overall loss for the complete isolation of the colloidal phase to a solid is estimated to be ~ 90%. Despite, this high degree of loss, it is still possible to measure a large suite of elements using ICP-MS because of the removal of interfering sea salts. Elemental concentrations in the colloidal isolate are generally similar to those found previously in isolates from coastal waters off southern California except for elements such as U, I, Mo, and As which are greatly enriched, possibly due to the longer processing time of the WHOI sample or higher organic content of the colloidal material. Elements presumed to exist as neutral or positively charged hydroxy species and those known to be complexed with organic ligands have the highest relative concentrations when compared to seawater values in the colloidal phase. Reducible elements which are normally present largely as oxyanions, such as Mo, As, V, W, U and I, have high colloidal concentrations but small enrichments. These elements are enriched in the WHOI sample compared to SIO samples. When normalized to average shale, rare-earth elements (REE) in the colloidal material exhibit a pattern similar to that of Buzzards Bay seawater with a flat light REE (LREE) pattern and an enrichment in heavy REE (HREE). When normalized to this seawater, there is an enrichment in the HREE and a negative Gd anomaly characteristic of uptake on organic material.

Organic and Inorganic Characterization of Marine Colloids

Abstract Isolates of the organic matter in the particulate, colloidal and dissolved states were obtained by tangential flow ultrafiltration through 0.40 μm polycarbonate and ∼ 1 nm (1000 NMWL∗) regenerated cellulose membranes and by solid-liquid reverse phase extraction techniques. the material was analyzed qualitatively by mass spectroscopy, proton nuclear magnetic resonance, Fourier transform infrared spectroscopy, high performance liquid chromatography with fluorescence detection of labelled primary amines and amino acids, and inductively coupled plasma/mass spectroscopy. All three states are characterized by similar organic chemistries. the marine colloidal state in coastal waters off the Californian coast contains primarily carbohydrates, fatty acids, minor amounts of proteinaceous compounds and electropositive elements including aluminium and iron. Aromatic molecules and olefinic functional groups are in low concentration. the colloidal state differs qualitatively from the particulate and dissolved ...