Comparison between urban Toronto PM and selected materials: aerosol characterization using laser ablation/ionization mass spectrometry (LAMS).

Laser ablation/ionization mass spectrometry (LAMS) of particulate matter (PM) was undertaken on-line in order to extend and contrast PM characterization. Qualitative on-line LAMS results for certified materials and Toronto source materials demonstrated the versatility and limitations of the technique. The observation of organic and inorganic components of certified materials verified the proper working condition of the in-house on-line LAMS. Organic and inorganic components of Toronto source materials were also observed with the on-line LAMS. Common components identified from both types of materials were Na, Al, Ca, Fe, and K. Other recognized components were compared with marker elements reported for some common PM emission sources. An in-house off-line LAMS was used to analyze urban Toronto PM deposited on glass substrates, while the on-line LAMS analyzed individual urban Toronto PM particles that were introduced directly into the instrument. Scanning electron microscopy (SEM), X-ray spectrometry and inductively coupled plasma atomic emission spectrometry (ICP-AES) were used for confirmatory purposes. Organic and inorganic components of urban Toronto PM at their typical ng/m3 concentrations were successfully observed in mass spectra using both off-line LAMS and on-line LAMS. Identified ions unique to each analyzed material were compared to identified ions of urban Toronto PM. The ability of LAMS to analyze individual respirable PM particles (viz. < 2 microns), both for inorganic trace elements and for organic components, greatly extended our capability to characterize PM and also to achieve estimates of concentration contributions of each material.

Measurement of PM10/2.5 fractionated respirable particles in urban Toronto by INAA, PIXE, ICP-AES, and LAMS. A comparison.

The chemical analysis of urban Toronto airborne particulate matter (PM), size segregated into respirable PM10/2.5, is presented. The characterization of PM by use of proton-induced X-ray emission analysis (PIXE), and inductively coupled plasma-atomic emission spectrometry revealed elemental information; a newer laser ablation-ionization mass spectrometry approach has the potential to expand the chemical information from PM by analyzing both the inorganic and organic species. These PM analytical approaches will be continued in the future for studying (1) emission source identification, (2) inhalation health hazards, and (3) urban smog chemistry.

A nuclear mass spectrometer for studying radon progeny clusters.

A Nuclear Mass Spectrometer (NMS) system was developed and used to investigate the cluster formation of radon progeny (218Po) in gaseous H2O and H2O-SO2 environments. This NMS combines the mass-separation ability of a mass spectrometer and the low detection limit of a surface barrier detector for alpha particles and enables the detection of individual radon progeny cluster ions of defined mass at the molecular level. Clusters in the form of 218Po+(H2O)n were experimentally observed for 218Po at a relative humidity of 0.1%. The number n ranged from 1 to 7 with 4 being the most abundant peak under these conditions. No charged cluster of 218Po was detected when the relative humidity was 90%, possibly due to a neutralization process. On addition of SO2 at a low relative humidity, 218Po+(H2O)n (H2SO4)m clusters were experimentally detected for the first time by the NMS system in this study with n from 0-4 and m from 0-3. The maximum distribution occurs at a radius of about 3.65 angstrom or a mobility of about 2.00 cm2 V-1 s-1. These maximum clusters correspond to a composition of 218Po+(H2SO4)2 or 218Po+(H20)2 (H2SO4)1.

Nuclear analytical techniques in environmental studies.

Nuclear analytical techniques are particularly suitable for measuring trace components in a wide variety of environmental samples, and for that reason, the techniques have made a significant contribution to environmental research. Presently, at a time when biosphere contamination and threats of global change in the atmosphere are of widespread concern, there exist an impressive array of specialized instrumental methods available to life scientists engaged in environmental studies; however, the nuclear techniques will probably continue to play a useful role in the future, notwithstanding the decreasing availability of necessary facilities, such as research reactors and accelerators. Reasons for the particular suitability of radionanalytical techniques are reviewed and illustrated by examples of recent applications to solid wastes, biomonitoring, and urban aerosol source identification in this laboratory.

Studies of incinerator ashes and environmental effects using radioanalytical techniques.

We have studied solid waste incinerator ashes to understand the leaching mechanism and speciation of toxic and other elements in them. Leaching media, such as water and acetate buffer, at various pHs were used. Incinerator ashes generally contain concentrations of many toxic elements, such as Cd, As, Hg, and Se. These elements are leached out rather easily. Many of the elements are leached within the first few minutes to an hour, and the majority of the elements reach peak equilibrium concentrations within 200 h. The pH and nature of the leaching medium are important factors in the leaching of the elements.

Hair trace elements in kidney dialysis patients by INAA.

INAA was used to determine selected trace elements--Ca, Al, P, and S--in 104 cleaned scalp hair samples from kidney dialysis patients (n = 54) and healthy controls (n = 50) in order to explore any differences in these elements that might be related to prolonged dialysis and/or associated medication in comparison with blood serum levels of Al and P measured in the same clinic at the time of hair sampling. After correction for P (and Si) interference in Al content, it was observed that there were no significant differences (at 95% confidence level) in hair Al and Ca, which had been expected, whereas while there were definite increases in P and S. Multivariant factor analysis applied to the same data set, however, showed some multiple correlations among four variables: serum Al, duration of dialysis, medication, and hair Al.

Studies of cadmium uptake in bone and its environmental distribution.

Rat experiments indicate that oral ingestion of cadmium through drinking water leads to an accumulation of cadmium in bone, in addition to liver and kidney. After five weeks of cadmium intake in drinking water (50 to 100 mg/L), the bone cadmium levels increased in proportion to the intake concentration. Bone and kidney histology showed no signs of bone or kidney damage up to 5 wk of cadmium ingestion. Cadmium accumulation in bone was a primary phenomenon and not secondary to renal failure. In addition, cadmium levels have been estimated in a variety of sources, e.g., foodstuff, fertilizer, and sewage sludge, using neutron and proton activation analyses and atomic absorption spectrophotometry. Cadmium levels of Canadian foods are in the range of 0.002-0.07 mg/kg, and soils are in the range of 0.55 to 1.72 mg/kg. Fertilizers contain cadmium from 0.3 to 1.25 mg/kg, whereas sewage sludge contains up to 122 mg/kg.

Waste water treatment for heavy metal toxins using plant and hair as adsorbents.

The adsorption of cadmium, mercury and lead by Cattails (Typha Plant) and human hair has been investigated to assess their possible use as adsorbents in the treatment of industrial wastewater. Capacity experiments were performed, and it was found that significant amounts of cadmium, mercury and lead were adsorbed by Cattails, while only mercury was adsorbed by hair. Depending upon the concentration, adsorption capacities varied from 1 to 27 mg of metal per gram of adsorbent. The relatively fast uptake of cadmium and lead by Cattail leaves suggests that a continuous process is viable. The results are similar in the case of hair and mercury.

Scalp hair as a monitor of community exposure to lead.

Lead was measured by photon activation analysis in scalp hair from three population groups with varied types of environmental exposure. Concentrations of lead in hair increased from rural to urban to smelter areas with medians of 9.1, 15.3, and 48.5 ppm, respectively. Boys under 16 residing near smelters showed consistently higher lead levels than girls of the same age group and from the same area. A history of exposure to lead was deduced from the distribution of concentration along the hair length by analyzing 1-or 2-cm segments of hair strands. A reasonably good blood lead-hair lead correlation was obtained for individuals who appeared to be in a steady state with respect to intake and excretion of lead. The analytical method for the photonuclear determination of lead in hair, the hair washing procedure, and the advantages of using hair as an epidemiologic monitor are described.

Lead contamination around secondary smelters: estimation of dispersal and accumulation by humans.

A high rate of lead fallout around two secondary lead smelters originated mainly from episodal large-particulate emissions from low-level fugitive sources rather than from stack fumes. The lead content of dustfall, and consequently of soil, vegetation, and outdoor dust, decreased exponentially with distance from the two smelters. Between 13 and 30 percent of the children living in the contaminated areas had absorbed excessive amounts of lead (more than 40 micrograms per 100 milliliters of blood and more than 100 micrograms per gram of hair) as compared with less than 1 percent in a control group. A relationship between blood and hair was established which indicated that the absorption was fairly constant for most children examined. It seemned that the ingestion of contaminated dirt and dusts rather than "paint pica" was the major route of lead intake. Metabolic changes were found in most of 21 children selected from those with excessive lead absorption; 10 to 15 percent of this group showed subtle neurological dysfunctions and minor psychomotor abnormalities.