Lead Aerosols Research Articles

Effect of aerosol size on the blood lead distribution of industrial workers.

The size distribution measurements of lead aerosol from a brass foundry and primary lead smelter are used to simulate blood lead distributions applying a pharmacokinetic model developed by Bernard. The predicted distribution of blood lead levels determined using the actual size distribution of lead aerosol are compared to the blood lead levels predicted according to the model assumptions adopted in setting the OSHA lead standard. In the furnace area of the smelter and the pouring area of the foundry the predicted mean blood lead level is higher than that found in the standard whereas, in the smelter's sintering and mixing operation the blood lead level is less than that suggested by the standard. The data support the conclusion that size-selective sampling needs to be considered for incorporation into the OSHA lead standard.

The use of Br/Pb ratios in atmospheric particles to discriminate between vehicular and industrial lead aerosol sources in the vicinity of a lead works—II. Ellesmere port, Cheshire

Lead and bromide in atmospheric particles were measured at two sites in the vicinity of a tetraalkyllead manufacturing plant. The Br results were used to estimate the relative proportions of vehicular and non-vehicular (presumably industrially-derived) particulate lead present in the atmosphere. The non-vehicular component was very variable over the 2-month study period, overall contributing about a quarter of the observed Pb. The relative proportions were found to be in good agreement with estimates of ground-level concentrations of Pb originating from the lead works stack derived from a Gaussian plume dispersion model.

Prediction of response of blood lead to airborne and dietary lead from volunteer experiments with lead isotopes.

To predict the response of blood lead to airborne and dietary lead requires knowledge of the rate of uptake of lead into the body from lung and gut, its subsequent partitioning between compartments, the stay time in those compartments, and its redistribution or excretion. Tracer studies with volunteers have shown no differences in systemic distribution of inorganic lead between tissues whether it is taken by inhalation, ingestion or injection. Lead is rapidly transferred from plasma to red cells, and there is slower movement thence into liver and other soft tissues, to bone, and to excreta. Work at Harwell and elsewhere with 203Pb has shown that the initial rapid distribution leaves rather over half the assimilated lead attached to red cells. The result is remarkably consistent, and applies also to dogs and baboons. The renal clearance (Vu) (ratio of U to CB, or daily urinary output expressed as mass of blood having the same lead content), and also the endogenous faecal clearance excretion rate (Vf), have been measured on human subjects with 203Pb. The results are consistent with Vu, as measured with stable lead, with many results giving Vu about 0.1 kg d-1. However, there is evidence that Vu increases when CB is elevated above the normal. This may explain the nonlinear relation between uptake of lead and the corresponding CB, which has been observed in humans exposed to environmental lead. Vf is about half Vu, and a similar result applies to calcium. The clearance rate Va of 203Pb from blood to bone has been measured, and a variety of human and animal data in the literature has been reviewed to support this result. Combined with bone turnover rates (from data on 90Sr), the postulated inputs to bone give estimates of skeletal burdens which agree with post-mortem results. The results are combined in a compartment model. The retention of lead aerosol in the lung, and uptake from the gut are then considered, with use made of radioactive tracer (203Pb), stable isotopic tracer (204Pb) and total lead measurements. Here there is great diversity of results. Particle size affects the fractional lung retention and the site of retention, which in turn affects the fractional uptake to blood. Presence or absence of food in the stomach when lead is ingested greatly affects the fractional gut uptake. Finally, a limited selection of results of volunteer exposures to stable lead in air or diet are reviewed.(ABSTRACT TRUNCATED AT 400 WORDS)

Enzymatic Changes in Alveolar Macrophages of Rats Exposed to Lead and Nickel by Inhalation

In previous inhalation studies, rats exposed to aerosol concentrations of lead oxide (Pb2O3), 150 μg/m3; lead chloride (PbCl2), 100 μg/m3; nickel oxide (NiO), 120 μg/m3; and nickel chloride (NiCl2), 109 μg/m3; significant changes were observed in the lungs and alveolar macrophages. In this study the hydroiytic enzymes, acetylesterase, acid and alkaline phos-phatases, lysozyme, and beta-glucuronidase, in alveolar macrophages and lung washout fluid from rats subjected to the inhalation of the lead and nickel aerosols were examined. Washed alveolar macrophages from animals exposed to lead and nickel aerosols were found to contain reduced quantities of the various hydrolytic enzymes (except for acetylesterase) when compared with those from control rats. On the other hand, a significant increase in enzymatic activity was noted in lung washout fluid from exposed animals. The functional efficiency of macrophages, relative enzyme changes, and the mechanism of action of metals are discussed. It is important to note that the changes observed in these studies were from animals exposed to metallic concentrations near their Threshold Limit Values.

Lead aerosol brownian collision rates at normal and elevated temperature: theory

Lifshitz-van der Waals theory including retardation is used to compute the attractive potential between pairs of lead spheres of 1-, 10-nm, and 1- and 10-nm radii at 293, 840, and 1059°K and the energies are plotted as functions of particle surface separations. These curves are then used to compute the particle collision rates using a recently published generalization of Fuchs' interpolation formula which includes the effect of particle interaction potentials. The results indicate a size-dependent enhancement of particle collision rates due to van der Waals attraction. Collision rates are shown to bracket the rate measured by Graham and Homer whose data fit a free-molecular self-preserving distribution. The effect of temperature upon collision rates is to decrease them as temperature rises despite a corresponding increase in the attractive interaction energy of the particles.

Formation of monodisperse lead aerosols and identification of particle number concentration by ice nucleation

Lead aerosols were generated to investigate the conditions for the formation of monodisperse aerosols in nitrogen stream. Aerosols of high monodispersity could be obtained by vaporizing lead at a temperature in the range of 1000° to 1150°C and by flowing nitrogen at a rte of 1.5 l/min. In order to produce “lead iodide aerosols” portions of the lead aerosols were conducted into a test chamber in which the atmosphere of iodine vapor had previously been prepared. This mixture containing the aerosols with low concentration was moderately stirred under different temperatures. “The lead iodide aerosols” were sampled with a syringe to be injected into a modified Bigg's test device for ice nucleation. The aerosols injected rapidly changed into ice crystals, which could grow in size. As the number of ice crystals could give that of lead iodide aerosols, the reactivity of lead aerosols with iodine vapor was investigated under various temperatures. An increase in temperature during the ageing of lead aerosols with iodine vapor promoted their reactivity.

Bromine to lead ratios in suspended air particulate matter in Greater Bombay

Measured ratios of Br/Pb in suspended air particulates at different locations in Greater Bombay are presented. Concentrations of Br and Pb were determined by non-destructive neutron activation analysis and by anodic stripping voltammetry, respectively. The Br/Pb ratio varied from 0.12 to 0.45 with an average of 0.25 ± 0.08, as compared to 0.39 in the antiknock fuel additive. The observed Br/Pb ratio for Bombay aerosols is in agreement with the corresponding values reported by others. The present measurements suggest that bromine loss rate is very little after the particles are deposited on the filter. The probable composition of lead aerosols is discussed.

Lead contamination of urban snow.

Lead content of newly fallen snow in an urban area ranges from 34 to 56 ppb. After falling, snow may incorporate major additional amounts of lead by dry deposition of lead aerosols from local sources. The highest concentration found was 2,700 ppb. Ingestion of lead-contaminated snow might pose a health hazard to inner city children.

Removal of lead aerosols from the exhaust gases of glassmaking furnaces

Removal of lead aerosols from the exhaust gases of glassmaking furnaces

Identification of lead compounds in urban air

IN the current controversy over the toxicity of environmental lead, one point still at issue is the efficiency of respiratory uptake of urban lead aerosol. The rate at which lead passes into the blood is a function of the particle size and the solubility of the deposited lead. Although data on the aerodynamic particle size distribution of urban lead aerosol are plentiful, little is known of the chemical nature, and thus solubility, of the lead and so this has hampered studies of respiratory uptake. Several analytical studies of fresh auto exhaust have been reported1, but Ter Haar and Bayard2 have shown that rapid changes occur after emission into the atmosphere. Although these workers characterised the major components of aged lead aerosol, limitations of the electron microprobe techniques which they used have been pointed out by Heidel and Desborough3, and considerable doubt must attach to the structural assignments. Using two techniques to enrich the lead fraction of urban aerosol, we have now identified the major components by X-ray powder diffraction (XRD).

Sonic agglomeration: a promising method of enhancing the collection efficiency of electrostatic precipitators

Experimental and theoretical studies of the effect of sound on the agglomeration of airborne particulates have been carried out to determine the feasibility of using sonic agglomeration as a means of enhancing the collection efficiency of electrostatic precipitators. Experiments were conducted using carbon black, kaolin clay, white lead, and fly ash aerosols. In each case, it was found that the rate of agglomeration increases with increasing concentration, sound pressure level, and exposure time, and with decreasing particle size. For each aerosol, there appears to be an optimum frequency at which the rate of agglomeration passes through a maximum. Experiments have also been conducted to determine if the efficiency of electrostatic precipitators, could be increased by pretreating the aerosol acoustically. Depending on the sound field conditions, the overall collection efficiency for the white lead aerosol was increased from 75% (on a mass basis) for the untreated aerosol up to as much as 90%. On the basis of these experimental results, it appears that sonic agglomeration has considerable potential for elimination of ultrafine particles prior to subsequent treatment using a conventional collection device such as the electrostatic precipitator.

Monitoring aerosol elemental composition in particle size fractions for predicting human respiratory uptake

Proton induced X-ray emission analysis is useful in measuring changes in particle size distribution of trace elements on exposure of aerosol to the human lung environment and deposition in the air-ways. PIXE analysis is also useful in detecting variations in particle size distributions of elements as they occur in the atmosphere. For the case of lead aerosol along a highway, it is shown that the extent and site of respiratory deposition of particles depend on their size, and the size distribution may vary under urban atmospheric conditions sufficiently to affect respiratory deposition efficiency.

Use of bromine levels in airborne particulate samples to infer vehicular lead concentrations in the atmosphere

X-ray fluorescence analysis has been employed to assess the feasibility of using the mean Br/Pb ratio for motor spirit to convert the Br level for atmospheric particulates to an atmospheric vehicular lead level. Analysis of air samples in Perth, Western Australia, has shown that the procedure is distinctly promising as the mean Br/Pb ratios of 0.61 ± 0.02 and 0.59 ± 0.05 for motor spirit and atmospheric particulate, respectively, are in excellent agreement. These ratio values are grossly different from the means of the corresponding values reported in a number of U.S. studies, 0.39 and 0.25 ± 0.03, respectively, due apparently to the use in Australia of lead additives which differ in composition from those employed in the U.S. This points to there being major differences in the character of vehicular lead aerosols found in Australia and the U.S. and highlights the need to determine the Br/Pb ratio for each region under study if the ratio is to be used to estimate the extent of atmospheric vehicular lead. The results indicate that PbBr 2 is amongst the most populous lead particuläte species in Perth aerosol.

Physiological effects, wind reentrainment, and rainwash of lead aerosol particulate deposited on plant leaves

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPhysiological effects, wind reentrainment, and rainwash of lead aerosol particulate deposited on plant leavesRoger W. Carlson, Fakhri A. Bazzaz, James J. Stukel, and James B. WeddingCite this: Environ. Sci. Technol. 1976, 10, 12, 1139–1142Publication Date (Print):November 1, 1976Publication History Published online1 May 2002Published inissue 1 November 1976https://doi.org/10.1021/es60122a001RIGHTS & PERMISSIONSArticle Views101Altmetric-Citations21LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (520 KB) Get e-Alerts Get e-Alerts

Lead aerosol pollution in the High Sierra overrides natural mechanism which exclude lead from a food chain.

Most of the lead contained in sedge and voles (mountain meadow mice) within one of the most pristine, remote valleys in the United States is not natural but came from smelter fumes and gasoline exhausts. In a food chain, natural mechanisms do not allow lead to accompany the bulk of the nutritive metals as they proceed to higher trophic levels. This exclusion can be expressed quantitatively by a comparison of lead/calcium ratios at successive trophic levels. This ratio decreased by an overall factor of 200 in proceeding from rock, to soil moisture, to sedge, to vole. This factor would have been 1200 if lead aerosols had not collected on sedge leaves and circtumvented the tendency by sedge to exclude lead from the nutritive metals it absorbed from soil moisture.

Regional and historical aspects of lead pollution in Britain.

Two major periods of increase in atmospheric lead concentrations have been recognized in the Northern Hemisphere—the first resulting from the rapid growth of industry during the eighteenth and nineteenth centuries, the second from the great expansion of motor vehicle traffic since the end of the Second World War1,2. There is clear evidence of lead pollution caused by motor vehicles close to busy roads2–4, and the three-fold increase in lead concentrations in snow from the Greenland ice-cap during the past 20 yr has also been correlated with the emission of lead aerosols from car exhausts1. In Britain many minerals, including lead, have been exploited over a long period of time, but some, including lead, have declined in importance in the past 100 yr after peak extraction levels in the eighteenth and nineteenth centuries. Thus it is probable that in certain areas of Britain heavy metal pollution has been worse in the past than it is now. This communication examines the historical trends in lead pollution in Britain by use of nineteenth century and present-day moss specimens, and by peat profiles—methods used also by other workers to demonstrate historical trends in heavy metal pollution in Scandinavia2,5.

An Apparatus for the Exposure of Plants to Selected Particulate Aerosols

A simple, inexpensive apparatus is described for the generation of particulate aerosols of known identity with aerodynamic size distributions characteristic of urban atmospheres. Means for using this system for the exposure of plants to selected lead aerosols are described. The design offers improvements over other systems used for similar purposes.

A study of aging of lead aerosols—I–II

These papers were of great interest to us for two reasons. We are studying the broad ecologie and epidemiologic effects of lead contamination of a valley due to a lead smelting plant, while another group is studying aerosol decontamination using the foam.

Lead aerosol baseline: concentration at White Mountain and Laguna Mountain, California.

The lead aerosol concentration at White Mountain, California, may be regarded as the present baseline concentration for atmospheric lead for the continental United States. The seasonal trend of lead aerosols at White Mountain and Laguna Mountain shows a summer maximum and a winter minimum. This is because both mountain sampling sites are well above the thermal (radiation) inversion, which normally occurs in the winter, trapping pollutants below the inversion boundary.

A study of aging of lead aerosols—I: Observations

The alteration of the size distribution of lead aerosols was studied by the sensitive analytical technique of anodic stripping voltammetry and using Andersen Samplers (multistaged cascade impactors) to collect and sort the aerosol by size. It was found that lead aerosol size distributions do not vary greatly from one source area (essentially an area of heavy automobile traffic) to another, and that the lead aerosol size distribution does not respond noticeably to change of weather within a source area for 24 h sampling times. Short-term aging in clear air was studied by comparing the lead size distributions at three locations from downtown Chicago (a source area) with those found several kilometers downwind over Lake Michigan (a non-source area). Long-term aging in clear air was studied by comparing the size distributions of lead aerosols of various ages collected on Lake Michigan. Ages were assumed to be the travel time from shore to the sampling location, computed by a simple trajectory analysis. The aging studies did not show a clear-cut systematic alteration of the lead aerosol size distribution, although the large particle end of the distribution showed reduced relative concentrations for aerosols ages of 6 h or older. These results suggest very little modification of the shape of the lead aerosol size distribution by non-precipitative atmospheric mechanisms for equivalent particle radii larger than 0.2 μm.