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Biomedical subjects

J C Méranger

Publications and source records attributed to J C Méranger.

14 recordsLinked to original sources
PubMed1989

Non-asbestos fibre content of selected consumer products.

The use of asbestos in consumer products such as joint compounds and modelling clays has been banned since these products, in normal use, have the potential to produce high levels of fibrous dusts in ambient air. However, we were concerned that the asbestos fibres present in these products would be replaced by other fibrous materials. X-ray diffraction and transmission electron microscopy analyses were performed to identify the crystalline components, including mineral fibres, in a selection of 45 samples. Using quantitative X-ray diffractometry, it was established that the fibrous content of several consumer products was in the range of 1-5%. The widespread use of attapulgite in cat litters, joint and spackling compounds and to a lesser extent in art supplies was confirmed. It was also shown that the attapulgite fibres detected were generally in the same size range as chrysotile, with diameters of 0.03-0.5 microns and lengths up to 4 microns.

Canada↗
PubMed1987

Indoor-outdoor levels of nitrogen and sulphur species and their relation to air flow in Antigonish, Nova Scotia.

A study was conducted in Antigonish, Nova Scotia, to determine the extent to which acid rain related pollutants are present in indoor ambient air. The pollutant study included: fine (0 to 2.5 micron) and coarse (2.5 to 10 micron) particulates, sulphates, nitrates, acidity (H2SO4 and HNO3), SO2 and NO2. During the 3 1/2 month study, maximum levels of 173n equivalent/m3 fine sulphate and 55 n equivalent/m3 H2SO4 were recorded for outdoor air within the town site compared to corresponding values of 110 n equivalent/m3 and 13 n equivalent/m3 for indoor air. Based on back trajectory analysis, wind direction, and sulphuric acid content, it was postulated that local or medium range pollution sources are predominant in the winter while long range transport originating from the United States produces the major episodes when SW winds are persistent.

Air Movements↗
PubMed1985

Preconcentration of cadmium, chromium, copper and lead in drinking water on the polyacrylic ester resin, XAD-7.

The conditions (e.g. pH, resin, particle size, foreign ions) affecting the uptake of Cd(II), Cr(III), Cu(II) and Pb(II) from aqueous solution by the SM-7 (also called XAD-7) resin, were studied. Based on these studies, a two-column method was developed to overcome the effect of complexation by humic substances. The method was successfully tested with the NBS multielement water standard, SRM 1643a, and was subsequently applied to enrich Cd(II), Cr(III), Cu(II) and Pb(II) in 15 drinking water samples from Hamilton, Ontario. The metals were determined using graphite furnace atomic absorption spectrometry. The results for the drinking water samples showed that leaching of copper and lead occurred from the distribution system.

Acrylic Resins↗
PubMed1982

Simultaneous determination of 20 elements in some human kidney and liver autopsy samples by inductively-coupled plasma atomic emission spectrometry.

The argon supported inductively coupled plasma--atomic emission spectrometer (ICP--AES) is found to be an attractive analytical tool for the simultaneous multi-element determination of major, minor and trace elements in human liver and kidney specimens. The sample is digested with a mixture of HNO3--HClO4. The damp residue is taken up in HCl, aspirated into the plasma and the resulting emission signals are detected by a polychromator where the analytical lines of the 20 elements determined are included as fixed channels. The method is rapid, precise, sensitive, less subject to interferences and cost-effective. A total of 20 elements in about 40 autopsy samples of human kidney (cortex and medulla) and liver taken from Canadian adults living in the Great Lakes Region of Ontario were determined using the wet digestion-ICP--AES technique.

Adult↗
PubMed1981

Survey for cadmium, cobalt, chromium, copper, nickel, lead, zinc, calcium, and magnesium in Canadian drinking water supplies.

A second national survey was done to ascertain the levels of Cd, Co, Cr, Cu, Ni, Pb, Zn, Ca, and Mg in Canadian drinking water supplies. Raw, treated, and distributed water samples collected from 71 municipalities across Canada were analyzed both by atomic absorption spectrophotometry using the direct method and by an APDC-MIBK extraction procedure. As in the first national survey, the amounts of trace metals found in the 3 types of water samples were essentially the same. Contamination of the water supplies with these metals except Cu and Zn was minimal during treatment and distribution. For Canadian drinking water, the median and extreme values expressed as ng metal/mL water were: Cd less than or equal to 0.02 (less than or equal to 0.02-0.07), Co less than or equal to 2.0 (less than or equal to 2.0-6.0), Cr less than or equal to 2.0 (less than or equal to 2.0-4.1), Cu less than 10 (less than or equal to 10-900), Ni less than or equal to 2.0 (less than or equal to 2.0-69.0), Pb less than or equal to 1.0 (less than or equal to 1.0-79.7), and Zn less than or equal to 10 (less than or equal to 10-750). Hardness values as mg CaCO3/L ranged from 6.7 in St. John's, Newfoundland, to 328.3 in Portage La Prairie, Manitoba. The median values for the Canadian drinking water supplies were well below the maximum permissible limits set by Health and Welfare Canada and the World Health Organization.

Canada↗
PubMed1980

Direct methods for the determination of lead in whole blood by anodic stripping voltammetry.

Two methods for the direct determination of lead in whole blood by anodic stripping voltammetry (ASV) are described. The procedure in both methods involved the mixing of micro blood samples with a metal releasing reagent, Metexchange, and electrochemical analysis using carbon electrodes. A multiple Anodic Stripping Analyzer equipped with composite graphite mercury electrodes and a Charge Transfer Analyzer equipped with a mercury film electrode were employed. The standard addition method was used to minimize the matrix effects of whole blood. The ASV results correlated well with those obtained by flameless atomic absorption analysis. The methods are simple, reliable, and suitable for applications in the clinical field. The procedure using the Charge Transfer Analyzer is recommended because of its sensitivity and rapidity.

Adult↗
PubMed1977

Implications of inorganic/organic interconversion on fluxes of arsenic in marine food webs.

An organic form of arsenic is commonly encountered in marine organisms; in greysole and shrimp, it accounted for all arsenic found in muscle tissue. It has been isolated from flounder tissue by two independent procedures; it was hydrophilic, cationic, and was not decomposed to inorganic arsenic by hot nitric and sulfuric acids. NMR spectroscopy indicated all nonexchangeable protons to be equivalent; they behaved more like N-methyl protons than As-methyl protons. High-resolution mass spectroscopy from a heated probe yielded a spectrum corresponding to tetramethylarsonium (AsMe4+); the authentic ion, however, had TLC and ion-exchange behavior different from that of the natural product. Infrared spectrometry likewise produced conflicting or uninterpretable data. Decomposition of the compound for analytical purposes was accomplished by dry ashing under oxidizing conditions. Sea urchins, like trout, converted arsenic to an organic form, but to a more limited degree. Arsenic found naturally in sea urchins and in a species of macroalga was also organic. In individual containers, sea urchins were fed on the alga for 7 weeks. During this time they consumed 0.203 +/- 0.075 mg total As and excreted only 0.036 +/- 0.015 mg as feces. Measurement of inorganic As in the seawater did not account for the discrepancy, but measurements of total As did (0.202 +/- 0.095 mg). Sea urchins, like humans, appear to be able to rapidly excrete these organic forms of arsenic.

Animals↗
PubMedDate not supplied

The effects of storage times, temperatures and container types on the accuracy of atomic-absorption determinations of Cd, Cu, Hg, Pb and Zn in whole heparinized blood.

The concentration changes of five different heavy metals in whole blood were tested under a variety of storage conditions. Changes were observed for hourly, daily and weekly periods at four temperatures (-70, -10, 4 and 22 degrees C) and in six different container types, (pyrex and soda glass, two polyethylene, polypropylene, polystyrene and polycarbonate). Rapid, direct-dilution, heated graphite furnace atomic absorption (AA) techniques were developed for analysis of cadmium, copper, lead, and zinc, while mercury was analyzed by the cold vapor flame atomic absorption spectroscopy (FAAS) method. The levels of all metals changed significantly in one week at almost all temperatures in all containers. Concentrations of cadmium, copper and zinc increased probably through leaching processes while lead and mercury decreased through probable hydrolysis and vaporization, respectively. Commercially cleaned polypropylene tubes did not perform significantly better than acid washed vessels. In the absence of better vessels, storage must be as short as possible for meaningful metal concentration determinations.

Animals↗