Showing papers on "Particulates published in 1982"

Distribution of thorium isotopes between dissolved and particulate forms in the deep sea

Abstract: The distribution of 234Th, 230Th, and 228Th between dissolved and particulate forms was determined in 17 seawater samples from the Guatemala and Panama basins. Sampling was carried out in situ with battery-powered, submersible pumping systems in which the seawater first passed through a Nuclepore filter (1.0-μm pore size) and then through a cartridge packed with Nitex netting that was impregnated with MnO2 to scavenge the dissolved Th isotopes. Natural 234Th was used as the tracer for monitoring the efficiency of scavenging. For all three isotopes, most of the activity was found in the dissolved form. On the average 4% of the 234Th, 15% of the 228Th, and 17% of the 230Th occurred in the particulate form, though the percentages were found to be strongly dependent on particle concentration. These distributions are not consistent with chemical scavenging models that assume irreversible uptake of Th on particle surfaces. The results can be explained, however, if continuous exchange of Th isotopes between seawater and the particle surfaces is assumed. Vertical profiles of both particulate and dissolved 230Th show increasing concentrations with depth, as required by the assumption of reversible exchange. Some of the dissolved 230Th profiles, however, show a reversal of this trend near the bottom, indicating accelerated scavenging near the water/sediment interface. Kinetics of both adsorption and desorption can be examined if at least two Th isotopes are measured in the same samples. Results show that reaction times are short (a few months) compared to the residence time of suspended matter in the deep ocean (several years), indicating that particles suspended in the deep sea are close to equilibrium with respect to exchange of metals at their surfaces.

Particulate Matter Associated with Vehicles on the Road

Abstract: Experiments at the Allegheny and Tuscarora Mountain Tunnels of the Pennsylvania Turnpike in 1975–1979 have resulted in a comprehensive description of the airborne particulate matter associated with highway traffic. Because of strong variations of traffic composition with time, emission rates of most species were resolvable into emission rates for each of the two vehicle categories: gasoline-powered vehicles and heavy-duty diesels. Thirty-four elements were identified, accounting for all of the vehicle-derived airborne particulate mass. The principal component was carbon (elemental and organic) from exhausts of heavy-duty diesels, which comprised on the average 10%–15% of the traffic. Per vehicle-kilometer, diesels were the preponderant source of most of the other species as well. Other emissions resulted from oxidation of diesel-fuel sulfur to H2SO4 (5% of the particulate mass total for traffic overall), inorganic additives and adventitious components of fuels and motor oils (10% of the overall mass total...

Identification of atmospheric particulate sources in Washington, D.C. using chemical element balances

Abstract: During the summer of 1976, 130 air-filter samples were collected at 10 sites in the Washington, D.C., area and analyzed for 39 elements, with 37 samples also being analyzed for SO/sub 4//sup 2 -/, NO/sub 3//sup -/, and NH/sub 4//sup +/. Concentration patterns were interpreted by using chemical element balances for seven sources: coal, oil and refuse combustion, soil dust, motor-vehicle emissions, limestone, and marine aerosols. For 35 nonvolatile elements, predicted concentrations were, on the average, within a factor of 1.93 of observed values. Predicted concentrations of primary particulate matter plus SO/sub 4//sup 2 -/, NO/sub 3//sup -/, and NH/sub 4//sup +/ account for 65% of measured total suspended particulate (TSP) matter, the remainder presumably being condensed water, organic material, and sources not included. The largest fraction of primary TSP matter is soil, dust, much of which is entrained by urban activities. The limestone component may originate from agricultural liming, construction projects, or abrasion of concrete. Most elements are reasonably well fitted, major exceptions being Cr, Cu, Ni, and a small-particle component of Mn.

Uptake of trace metals by sediments and suspended particulates: a review

Abstract: This review addresses three of the possible mechanisms by which trace metals can be concentrated by sediments and suspended particulate matter. These are physic-chemical adsorption from the water column, biological uptake particularly by bacteria and algae, and the sedimentation and physical entrapment of enriched particulate matter. The relative importance of these three mechanisms will be different, depending upon the aqueous system, but there have been insufficient studies to allow the establishment of even ‘rule-of-thumb’ guidelines, as yet, about their quantitative importance under different conditions.

Turbulence in two-phase dispersed flows

Abstract: Turbulence measurements in dispersed-bubble two-phase pipe flow, using laser velocimetry techniques, are presented. The turbulence-intensity measurements show a strong dependence on the quality of the flow. A theoretical basis for the prediction of turbulence levels in two-phase flows is proposed. The approach is applied to dispersed-gas/liquid (bubbly) and solid/gas (particulate) two-phase flows, for which experimental data are available, with excellent results.

Lipids in aerosols from the tropical North Pacific: Temporal variability

Abstract: Lipid components in air masses were sampled during 1979 at Enewetak Atoll as part of the Sea-Air Exchange Program (SEAREX). The investigation was designed to determine the terrestrial and marine sources and to search for atmospheric transformation processes of oceanic aerosols. Four particulate lipid compound classes (aliphatic hydrocarbons, fatty alcohols, fatty acid esters, and salts) all unequivocally show a terrestrial vascular plant source. Their temporal trends correlate well with those of other continental source indicators, such as particulate Al and 210Pb. These particulate lipids originate from wind erosion of Eurasian soil and direct emission from vegetation rather than from biomass burning, anthropogenic sources, or evaporation/condensation processes. A series of apparently marine-derived lower molecular weight alcohols and fatty acid salts and esters are also present. The more typically marine polyunsaturated acids are absent, probably due to their rapid rates of atmospheric degradation. A marine origin for the fatty acid salts

The dynamics of estuarine manganese cycling

Abstract: Seasonal observations of dissolved managnese in the Tamar Estuary,south-west England have demonstrated pronounced temporal and spatial variability in the distribution of this component. Simultaneous observations of physical and physico-chemical properties of the estuarine system, together with kinetic measurements of dissolved managenese behaviour in isolated samples, have demonstrated that the observed distributions are the instantaneous product of dynamic interactions involving external sources and internal input and removal processes. Dissolved manganese is mobilized internally from reduced sedimentsduring advective resuspension of bed material so that this input is regulated by temporal and spatial variations in tidal stress. Manganese is returned to the sediments by continuous uptake on to suspended particles. The rate of this process is responsive to changes in suspended particulate load, ionic strength pH and temperature. The reaction changes from zero-order kinetics in freshwater to first-order kinetics characteristic of the saline medium, with marked deceleration in effective, removal rate, following small increases in salt concentration. Relative changes in the first-order removal rate throughout the estuary are consistent, but there are considerable temporal variations in the absolute rates. This is partially attributable to variations in the quality, as well as the quantity, of the suspended particles. These results indicate that changes in the relative effectiveness of both the input and removal mechanisms, which lead to internal cycling of manganese and to variable distributions of dissolved managanese within the estuary, are closely coupled to the internal behaviour of particles and hence to the tidally-induced oscillations in bed stress. This observation has been confirmed by sequential recordings of dissolved manganese distributions through a spring tide to neap tide period. Furthermore, climatic events producing enhanced disturbance of bed sediment have been shown to induce a similar sequence of events to that arising from tidally induced net mobilization of bed material.

Identification of nitroaromatics in diesel exhaust particulate using gas chromatography/negative ion chemical ionization mass spectrometry and other techniques

Abstract: A series of nitroaromatic compounds were identified in diesel exhaust particulate extract. Isomers of nitroanthracene (and/or nitrophenanthrene) and nitropyrene (and/or nitrofluoranthene) were unequivocally identified. Alkyl homologues of nitroanthracene through C/sub 3/-alkyl-nitroanthracene were tentatively identified. In addition, a C/sub 18/H/sub 11/NO/sub 2/ isomer was tentatively identified. The nitro-substituted polynuclear aromatic hydrocarbons (PAHs) were found in two fractions of diesel exhaust particulate extract collected from a low-pressure liquid chromatography (LPLC) column. One of the two fractions containing nitroaromatic constitutents accounted for a large percentage of the mutagenicity of the crude particulate extract. Initial identification were made by using high-resolution gas chromatography/electron impact mass spectrometry/computer (GC/EIMS) and negative ion chemical ionization mass specrometry/computer (GC/NICIMS). These identifications were confirmed by direct probe high-resolution mass spectrometry (HRMS) and gas chromatography/Fourier transform infrared spectrometry (GC/FT IR). The relative merit of each analytical technique for the determination of nitroaromatics is discussed with emphasis on the usefulness of GC/NICIMS as a means of analyzing for nitro-substituted PAHs.

Chemical Characterization of Organic Adsorbates on Diesel Particulate Matter

Abstract: The organic adsorbates on diesel particulate matter are characterized by a combination of chromatographic and mass spectrometric techniques. These data are obtained for particulate matter generated under constant engine operating conditions using a model fuel and a synthetic lubricant, with air or argon/oxygen as the oxidant systems. The significance of these results is that the polycyclic aromatic compounds which were produced by these experiments are the inherent products from the diffusion controlled combustion in a diesel engine. Also, these results suggest that there are common intermediates which produce the polycyclic aromatic compounds that are independent of the structure and chain length of the hydrocarbon fuel. 27 refs.

Particulate Carbon at Various Locations in the United States

Abstract: Particulate elemental and organic carbon concentrations were determined on filters collected between 1972 and 1980 at ten United States’ sites representing urban, suburban, rural, and remote areas. The results showed that particulate elemental carbon is ubiquitous with mean concentrations ranging from 1.1 micrograms per cubic meter at the remote site in South Dakota to 13.3 micrograms per cubic meter in a congested area in New York City. About 80% of the elemental carbon mass consists of particles with a diameter of less than 2.5 micrometers. Particulates in this size range are responsible for most pollutant-related visibility reductions. Since it appears that elemental carbon is the only light-absorbing particulate species, the specific light-absorption coefficient for elemental carbon was calculated to be 12.7 m2/g while the specific light-scattering coefficient was 3.2 m2/g. Using these coefficients, the contributions of elemental carbon to the observed visibility reduction at the various sites are estimated. These range from 6 to 38%. Also discussed are the seasonal and diurnal variations of particulate elemental and organic carbon as well as the contribution from secondary organic particulates. In addition, an updated carbon-source apportionment, based on recent analytical developments, is presented for the Denver area.

Emissions and Air Quality Relationships for Atmospheric Carbon Particles in Los Angeles

Abstract: An emission inventory for fine particle aerosol carbon has been constructed for the Metropolitan Los Angeles area and compared to the results of ambient sampling. Information on the level of source activity, total aerosol emission rate, particle size and chemical composition was used to estimate the mass emission rate of particulate organic and elemental carbon in this urban area. It was found that carbonaceous particle emissions to the atmosphere arise from more than fifty classes of mobile and stationary air pollution sources. Emission data for elemental carbon at present contain significant uncertainties. Methods for verifying the consistency of carbonaceous aerosol emission inventories thus are important. Verification tests based on comparison of the ratio of organic carbon to elemental carbon and lead in source emissions versus that measured in the atmosphere were developed in this paper. Using these tests, excellent agreement was found between the emission inventory and results of ambient sampling in Los Angeles during January and February 1980.

Particulate Emission Factors for Small Wood and Coal Stoves

Abstract: Emission factors for particulate matter and carbon monoxide have been measured for wood, anthracite coal, and bituminous coal burned in residential heaters operated at less than 15 kW (50,000 Btu/hr). In these studies the stove effluent is mixed with about four volumes of outside air and samples are collected about two minutes after mixing. The main purpose of using this sampling method is to simulate atmospheric conditions more closely. Particulate samples are collected on 20 × 25 cm filters after cyclone preseparation of particles larger than 4 μm. Carbon monoxide concentrations are measured with Draeger tubes. Particulate emission factors for wood ranged from 1.6 to 6.4 g/kg (fuel) and were found to depend on the fuel load and the firing rate, as indicated by earlier studies. These values are substantially less than the values obtained previously for stoves operated under similar conditions. The average particulate emission factors for bituminous and anthracite coal are 10.4 and 0.50 g/kg, respectively...

Algal-availability of particulate phosphorus from diffuse and point sources in the lower Great Lakes basin

Abstract: Control of phytoplankton production in the Great Lakes can be achieved most efficiently by limiting inputs of biologically available P. We report the results of studies performed to characterize the chemical forms and availability of particulate P in wastewater and tributaries which enter the lower Lakes, the eroding bluffs which border Lake Erie, and bottom samples from the near-shore of western Lake Erie. Rates of release of available P were estimated from a simple first-order model of the process, as observed during algal bioassays. Available P in wastewater samples, as a fraction of total particulate P, was affected minimally by wastewater treatment, including chemical precipitation and filtration; it correlated well with levels of total particulate P. Available particulate P levels in fluvial suspended sediments showed regional uniformity, but appeared to be strongly dependent on levels of both NaOH-P and CDB-P. Rates of release of available P decreased during wastewater treatment to values which were similar in magnitude to those observed for fluvial sediments. Release rates, however, were not related to any of the particulate P fractions which were measured. Analysis of the bluff and bottom samples indicated that P availability in the former was negligible, but the latter contained levels which approached those of wastewater particulates, though available P was released from the bottom sediments at relatively low rates.

The input of atmospheric n-C10 to n-C30 alkanes to the ocean

Abstract: There are few data on organic compounds in the marine atmosphere. The only class for which any significant data base exists is the n-alkanes. Using available data on n-C10 to n-C30 alkanes in aerosols, rain, and in the gas phase from Atlantic, Pacific, and Indian Ocean regions, crude estimates of the deposition of n-alkanes to the world ocean are made. Deposition of gaseous and particulate n-alkanes by rain scavenging, of particulate n-alkanes by dry deposition, and of gaseous n-alkanes by direct vapor exchange with the ocean are evaluated. Rain scavenging of particulate n-alkanes appears to be the primary transport path to the ocean from the atmosphere. The total input of n-alkanes to the ocean from the atmosphere is estimated to be from 0.04 to 0.4 Tg/yr. The accuracy of these estimates could be evaluated by the analysis of carefully collected rain samples over several oceanic regions. More precise estimates of the atmospheric input of organic material to the ocean will have to await more information on the inputs of the various organic compound classes to the sea surface and further understanding of the reaction products, pathways, and rates of transformation of these compounds in the atmosphere.

Seasonal and vertical variations in the chemical composition of suspended particulate matter in an oxygen-deficient fjord

Abstract: Chemical analysis of suspended particulate matter in marine waters gives insight into important geochemical processes. Additionally, fjords offer suitable locations to study these processes. The Bunnefjord in south-east Norway was selected for a 1-year study of the vertical and seasonal variations in the particulate matter chemistry. Analysis of particulate Al, Si, P, Fe and Mn on Nuclepore membrane filters by X-ray fluorescence spectrometry elucidates the distribution of various particulate matter phases in the water column. While particulate Al, Si and P are abundant above the halocline due to the influence of river water (Al), diatoms (Si) and organic matter (P), particulate Fe and Mn phases preferentially occur in the lowoxygenated bottom water. The latter is a result of redox reactions at or near the sediment-water interface. The mobility of Mn is particularly well demonstrated, showing a rapid loss of Mn from the sediments when the oxygen concentration in the bottom water dropped below 1 ml l−1. The flux of Mn from the sediments to the water and the conversion of dissolved Mn to a particulate phase was estimated to a minimum of 0·7 μg cm−2 day−1.

Fireplaces, Furnaces and Vehicles as Emission Sources of Particulate Carbon

Abstract: Particulate carbon in the atmosphere results from the incomplete combustion of fossil and contemporary fuels. Fuel-specific emission rates of elemental and organic carbon are presented for residential wood-burning fireplaces and gas furnaces as well as precatalyst, catalyst, and diesel automobiles. The fireplace emissions from several types of wood were collected from residential chimneys using standard EPA source-sampling procedures. Furnace emissions were collected with a laboratory setup and the effects of variations in stoichiometry and cycling rate were evaluated. Automotive emissions were collected from a dilution tunnel using two driving cycles both at sea level and high altitude. Carbon analysis was performed by several methods, including temperature programming, combustion analysis, and solvent extraction. Organic carbon associated with the particulate emissions was also tested for benzo(a)pyrene content. The emission rates and annual fuel consumption data were used to estimate the relative strength of these particulate carbon sources on a national basis.

Process for cleaning an oil-contaminated brine containing particulate drill cutting solids

Abstract: A process for cleaning oil-contaminated well bore fluids, and particulate solids. An oil-contaminated well bore fluid, or particulate solids, or both, is admixed with an aqueous polymeric solution and diatomaceous earth, and the admixture filtered to free the oil-contaminated well bore fluid, or solids, of oil which is separated therefrom. The oil-decontaminated well bore fluid is thereby rendered suitable for reuse, and residual solids useful for reblending with the original well bore fluid, or rendered environmentally acceptable for discharge.

Calcined, high surface area, particulate matter, processes using this matter, and admixtures with other agents

Abstract: This invention is concerned with production and use of high surface area particulate matter by calcining a charge of clay mineral, feldspar, zeolite, coal ash, fly ash, pozzolan or volcanic ash for a time to develop fractures which increase the surface area of the particles. Vacuum calcining decreases the calcining time. The calcined matter desirably has an analysis including: calcium oxide, about 20-40 weight %; aluminum oxide, about 15-35 weight %; and silicon oxide, about 20-40 weight %. The calcined particulate matter can be used in the treatment of impure aqueous materials; the matter is denser than water and sludge settles rapidly and completely. The calcined matter interacts with heavy metal ions to form tightly bound sludge that is nonhazardous for landfill disposal. The calcined matter can be combined with conventual coagulants, flocculants, filter aids, or activated carbon to obtain a multipurpose treating agent. The calcined particulate matter can be combined with exotic waste water treating agents obtaining results not attainable by these exotic agents alone. The exotic agents are borohydride, dialkyldithiocarbamates where alkyl has 1-5 carbon atoms and `carbamate` has alkali metal or ammonium, dithionites, glycine, hydrazine salts, metabisulfites, polygalacturonic acid, water soluble sulfides and sulfites, and cellulose and starch xanthates.